Patent Publication Number: US-2006009833-A1

Title: Delivery system and method for bifurcated graft

Description:
RELATED APPLICATIONS  
      This application is a continuation-in-part of U.S. patent application Ser. No. 09/917,371, filed Jul. 27, 2001, by Michael V. Chobotov et al., entitled “Delivery System and Method for Bifurcated Endovascular Graft”, which is a continuation-in-part of U.S. patent application Ser. No. 09/834,278, filed Apr. 11, 2001, by Michael V. Chobotov et al., entitled “Delivery System and Method for Endovascular Graft,” Each application is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND  
      The present invention relates generally to a system and method for the treatment of disorders of the vasculature. More specifically, a system and method for treatment of thoracic or abdominal aortic aneurysm and the like, which is a condition manifested by expansion and weakening of the aorta. Prior methods of treating aneurysms have consisted of invasive surgical methods with graft placement within the affected vessel as a reinforcing member of the artery. However, such a procedure requires a surgical cut down to access the vessel, which in turn can result in a catastrophic rupture of the aneurysm due to the decreased external pressure from the surrounding organs and tissues, which are moved during the procedure to gain access to the vessel. Accordingly, surgical procedures can have a high mortality rate due to the possibility of the rupture discussed above in addition to other factors. Other risk factors for surgical treatment of aortic aneurysms can include poor physical condition of the patient due to blood loss, anuria, and low blood pressure associated with the aortic abdominal aneurysm. An example of a surgical procedure is described in a book entitled  Surgical Treatment of Aortic Aneurysms  by Cooley published in 1986 by W.B. Saunders Company.  
      Due to the inherent risks and complexities of surgical intervention, various attempts have been made to develop alternative methods for deployment of grafts within aortic aneurysms. One such method is the non-invasive technique of percutaneous delivery by a catheter-based system. Such a method is described in Lawrence, Jr. et al. in “Percutaneous endovascular graft: experimental evaluation”,  Radiology  (May 1987). Lawrence described therein the use of a Gianturco stent as disclosed in U.S. Pat. No. 4,580,568. The stent is used to position a Dacron fabric graft within the vessel. The Dacron graft is compressed within the catheter and then deployed within the vessel to be treated. A similar procedure has also been described by Mirich et al. in “Percutaneously placed endovascular grafts for aortic aneurysms: feasibility study,”  Radiology  (March 1989). Mirich describes therein a self-expanding metallic structure covered by a nylon fabric, with said structure being anchored by barbs at the proximal and distal ends.  
      One of the primary deficiencies of the existing percutaneous devices and methods has been that the grafts and the delivery systems used to deliver the grafts are relatively large in profile, often up to 24 French, and stiff in longitudinal bending. The large profile and relatively high bending stiffness of existing delivery systems makes delivery through the vessels of a patient difficult and can pose the risk of dissection or other trauma to the patient&#39;s vessels. In particular, the iliac arteries of a patient are often too narrow or irregular for the passage of existing percutaneous devices. Because of this, non-invasive percutaneous graft delivery for treatment of aortic aneurysm is contraindicated for many patients who would otherwise benefit from it.  
      What is needed is an endovascular graft and delivery system having a small outer diameter relative to existing systems and high flexibility to facilitate percutaneous delivery in patients who require such treatment. What is also needed is a delivery system for an endovascular graft that is simple, reliable and that can accurately and safely deploy an endovascular graft within a patient&#39;s body, lumen or vessel.  
     SUMMARY  
      The invention is directed generally to a delivery system for delivery of an expandable intracorporeal device, specifically, an endovascular graft. Embodiments of the invention are directed to percutaneous non-invasive delivery of endovascular grafts which eliminate the need for a surgical cut-down in order to access the afflicted artery or other intracorporeal conduit of the patient being treated. Such a non-invasive delivery system and method result in shorter procedure duration, expedited recovery times and lower risk of complication. The flexible low profile properties of some embodiments of the invention also make percutaneous non-invasive procedures for delivery of endovascular grafts available to patient populations that may not otherwise have such treatment available. For example, patients with small anatomies or particularly tortuous vasculature may be contraindicated for procedures that involve the use of delivery systems that do not have the flexible or low profile characteristics of embodiments of the present invention.  
      In one embodiment, the delivery system has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft includes a portion having an expandable intracorporeal device. An elongate belt support member is disposed adjacent a portion of the expandable intracorporeal device and a belt is secured to the belt support member and circumferentially disposed about the expandable intracorporeal device. The belt member constrains at least a portion of the expandable intracorporeal device. A release member releasably secures the belt in the constraining configuration.  
      Another embodiment of the invention is directed to a delivery system that has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed adjacent a portion of the expandable intracorporeal device. A belt is secured to the belt support member and is circumferentially disposed about the expandable intracorporeal device. The belt has a configuration which constrains the expandable intracorporeal device and a release member releasably secures the belt in the constraining configuration. The belt may constrain any portion of the expandable intracorporeal device, such as a self-expanding portion of the expandable intracorporeal device. A self-expanding portion of the device may include a self-expanding member such as a tubular stent.  
      In a particular embodiment of the invention, a plurality of belts are secured to various axial positions on the belt support member, are circumferentially disposed about the expandable intracorporeal device and have a configuration which constrains the expandable intracorporeal device. At least one release member releasably secures the belts in the constraining configuration. Each belt can be released by a single separate release member which engages each belt separately, or multiple belts can be released by a single release member. The order in which the belts are released can be determined by the axial position of the belts and the direction of movement of the release member.  
      Another embodiment of the invention is directed to a delivery system for delivery of a self-expanding endovascular graft with a flexible tubular body portion and at least one self-expanding member secured to an end of the endovascular graft. The delivery system has an elongate shaft having a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed within the self-expanding member of the endovascular graft and a belt that is secured to the belt support member adjacent the self-expanding member. The belt is also circumferentially disposed about the self-expanding member and has a configuration that constrains the self-expanding member. A release wire releasably secures ends of the belt in the constraining configuration.  
      A further embodiment of the invention includes a delivery system for delivery of an endovascular graft with a flexible tubular body portion and a plurality of self-expanding members secured to ends of the endovascular graft. The delivery system has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft has an elongate guidewire tube disposed within the endovascular graft in a constrained state. A plurality of shape memory thin wire belts are secured to the guidewire tube respectively adjacent the self-expanding members. The belts are circumferentially disposed about the respective self-expanding members and have a configuration that constrains the respective self-expanding members. A first release wire releasably secures ends of the belts disposed about the self-expanding members at the proximal end of the endovascular graft in a constraining configuration. A second release wire releasably secures ends of the belts disposed about the self-expanding members at a distal end of the endovascular graft in the constraining configuration.  
      The invention also is directed to a method for deploying an expandable intracorporeal device within a patient&#39;s body. The method includes providing a delivery system for delivery of an expandable intracorporeal device including an elongate shaft having a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed adjacent a portion of the expandable intracorporeal device and a belt which is secured to the belt support member. The belt is circumferentially disposed about the expandable intracorporeal device and has a configuration that constrains the expandable intracorporeal device. A release member releasably secures the belt in the constraining configuration.  
      Next, the distal end of the delivery system is introduced into the patient&#39;s body and advanced to a desired site within the patient&#39;s body. The release member is then activated, releasing the belt from the constraining configuration. Optionally, the delivery system may also have an outer protective sheath disposed about the endovascular graft in a constrained state, the belt in its constraining configuration and at least a portion of the release wire disposed at the belt. In such an embodiment, the method of deployment of an expandable intracorporeal device also includes retraction of the outer protective sheath from the endovascular graft prior to activation of the release member.  
      In an embodiment of the invention directed to delivery of bifurcated intracorporeal device, an elongate shaft has a proximal section and a distal section. The distal section of the shaft has an elongate primary belt support member and at least one primary belt disposed on the primary belt support member. The primary belt support member is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A primary release member is configured to engage and releasably secure the primary belt in a constraining configuration. At least one elongate secondary belt support member is disposed adjacent the elongate primary belt support member. At least one secondary belt is disposed on the secondary belt support member. This at least one secondary belt is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A secondary release member is configured to engage and releasably secure the secondary belt in a constraining configuration.  
      In a method for deploying a bifurcated intracorporeal device within a patient&#39;s body, a delivery system for delivery and deployment of a bifuircated intracorporeal device is provided. The delivery system includes an elongate shaft having a proximal section and a distal section. The bifurcated intracorporeal device is disposed on the distal section of the elongate shaft. The distal section of the elongate shaft also includes an elongate primary belt support member and at least one primary belt secured to the primary belt support member. The primary belt is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A primary release member engages and releasably secures the primary belt in the constraining configuration. The distal section of the elongate shaft also includes at least one elongate secondary belt support member disposed adjacent the elongate primary belt support member. At least one secondary belt is secured to the secondary belt support member and is configured to be circumferentially disposed about a bifurcated intracorporeal device to at least partially constrain the device. A secondary release member engages and releasably secures the secondary belt in a constraining configuration.  
      The distal end of the delivery system is introduced into the patient&#39;s body and advanced to a desired site within the patient&#39;s body. The release members are then activated to release the belts from the constraining configuration and the device is deployed. Thereafter, the delivery system can be removed from the patient&#39;s body. In some embodiments of the invention, the secondary belt support member is detached and removed from the delivery system prior to withdrawal of the delivery system from the patient. In another embodiment, the secondary belt support member is displaced laterally towards the primary belt support member so as to be substantially parallel to the primary belt support member and enable withdrawal of the delivery system through an ipsilateral side of the bifurcated intracorporeal device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an elevational view in partial longitudinal section illustrating an embodiment of a delivery system for an expandable intracorporeal device having features of the invention.  
       FIG. 2  is a transverse cross sectional view of the delivery system of  FIG. 1  taken along lines  2 - 2  of  FIG. 1 .  
       FIG. 3  is a transverse cross sectional view of the delivery system of  FIG. 1  taken along lines  3 - 3  of  FIG. 1 .  
       FIG. 4  is a transverse cross sectional view of the delivery system of  FIG. 1  taken along lines  4 - 4  of  FIG. 1 .  
       FIG. 5  is a transverse cross sectional view of the delivery system of  FIG. 1  taken along lines  5 - 5  of  FIG. 1 .  
       FIG. 6A  is an enlarged elevational view in partial section of the delivery system in  FIG. 1 .  
       FIG. 6B  is an enlarged elevational view in partial section of the delivery system of  FIG. 1  with portions of the graft and self-expanding members cut away for clarity of view of the belt bushings.  
       FIG. 7A  is a perspective view showing release belt configurations having features of the invention.  
       FIG. 7B  is a perspective view showing an alternative embodiment of release belts.  
       FIG. 7C  is an end view showing an alternative embodiment of release belts.  
       FIG. 7D  is a perspective view of the embodiment of  FIG. 7C .  
       FIG. 7E  is an enlarged view of a particular coupling configuration between end loops of release belts.  
       FIG. 7F  is a perspective view, partially cut away, of a particular embodiment of an end loop of a release belt.  
       FIG. 7G  is a perspective view of an alternative embodiment of a release belt.  
       FIG. 7H  is a perspective view of an alternative embodiment of a release belt.  
       FIG. 7I  is a perspective view of an alternative embodiment of a branched release wire.  
       FIG. 7J  is an end view showing an alternative embodiment of a release belt.  
       FIG. 7K  is a transverse cross sectional view showing the alternative embodiment of the release belt configuration of  FIG. 7J  constraining a self-expanding member.  
       FIG. 7L  is a detail of the connection formed where a release wire is used with the alternative release belt embodiment of  FIGS. 7J-7K .  
       FIG. 8  is an elevational view in partial section of the proximal adapter shown in  FIG. 1 .  
       FIG. 9  is a diagrammatic view of a patient&#39;s body illustrating the patient&#39;s heart, aorta, iliac arteries, femoral arteries, and a delivery system having features of the invention disposed within the femoral artery and aorta.  
       FIG. 10  is a diagrammatic view of a delivery system having features of the invention disposed within an artery of a patient with an expandable intracorporeal device being deployed within the artery.  
       FIG. 11  is a diagrammatic view of a delivery system having features of the invention disposed within an artery of a patient with an expandable intracorporeal device being deployed within the artery.  
       FIG. 12  is an enlarged diagrammatic view of a delivery system having features of the invention disposed within an artery of a patient with an expandable intracorporeal device being deployed within the artery.  
       FIG. 13  is an elevational view in partial section of a connection between an inflation tube and an inflation port of an endovascular graft.  
       FIG. 14  is an elevational view in partial longitudinal section illustrating an embodiment of a delivery system for an expandable intracorporeal device having features of the invention.  
       FIG. 15  is a transverse cross sectional view of the delivery system of  FIG. 14  taken along lines  15 - 15  in  FIG. 14 .  
       FIG. 16  is an enlarged elevational view in partial section of the delivery system shown in  FIG. 14 .  
       FIG. 17  is an elevational view in partial section of the proximal adapter of the delivery system shown in  FIG. 14 .  
       FIG. 18  is an elevational view in partial section of an alternative embodiment of the proximal adapter of the delivery system shown in  FIG. 14  with a nested handle configuration.  
       FIG. 19  is an elevational view of a bifurcated stent graft suitable for delivery and deployment by embodiments of the invention.  
       FIG. 20  is a transverse cross sectional view of the stent graft of  FIG. 19  taken along lines  20 - 20  in  FIG. 19 .  
       FIG. 21  is a transverse cross sectional view of the stent graft of  FIG. 19  taken along lines  21 - 21  of  FIG. 19 .  
       FIG. 22  is a transverse cross sectional view of the stent graft of  FIG. 19  taken along lines  22 - 22  of  FIG. 19 .  
       FIG. 23  is an elevational view in partial section of an embodiment of a delivery system having features of the invention.  
       FIG. 24  is a transverse cross sectional view of the delivery system of  FIG. 23  taken along lines  24 - 24  of  FIG. 23 .  
       FIG. 25  is a transverse cross sectional view of the delivery system of  FIG. 23  taken along lines  25 - 25  of  FIG. 23 .  
       FIG. 26  is an elevational view in partial section showing an enlarged view of a distal portion of the delivery system of  FIG. 23 .  
       FIG. 27  is a transverse cross sectional view of the delivery system of  FIG. 26  taken along lines  27 - 27  of  FIG. 26 .  
       FIG. 28  is a transverse cross sectional view of the delivery system of  FIG. 26  taken along lines  28 - 28  of  FIG. 26 .  
       FIG. 28A  is a transverse cross sectional view of an alternative embodiment of a secondary belt support member of a delivery system similar in function to that shown in  FIG. 28 .  
       FIG. 28B  is an elevational view of the alternative embodiment of the secondary belt support member of  FIG. 28A .  
       FIG. 29  is a transverse cross sectional view of the delivery system of  FIG. 26  taken along lines  29 - 29  of  FIG. 26 .  
       FIG. 30  is a transverse cross sectional view of the delivery system of  FIG. 26  taken along lines  30 - 30  in  FIG. 26 .  
       FIG. 31  is an elevational view in partial section of the proximal adapter of the delivery system of  FIG. 23 .  
       FIG. 31A  is an elevational view in partial section of the proximal adapter of the delivery system of  FIG. 23 , showing an optional ripcord and flexible fill cathether.  
       FIG. 31B  is a simpler cross sectional schematic view of a bent or angled contralateral leg inflatable channel having a bead or lumen patency member disposed in a channel lumen taken along line  31 B- 31 B in  FIG. 19 .  
       FIG. 32  is a perspective view of the belt support member assembly at a distal portion of the delivery system of  FIG. 23 .  
       FIG. 33  illustrates a portion of the internal vasculature of a patient, including the aorta, iliac and femoral arteries branching therefrom.  
       FIG. 34  is a magnified view of the abdominal aorta area of the patient shown in  FIG. 33  and shows a guidewire positioned in the aorta from the right iliac artery.  
       FIGS. 35-37  illustrate the magnified view of the abdominal aorta of the patient shown in  FIG. 33  and depict a deployment sequence of the bifurcated endovascular stent graft of  FIG. 19  with the delivery system of  FIG. 23 .  
       FIG. 37A  is a perspective view of a marker disposed on the delivery system distal section in the vicinity of the nosepiece.  
       FIG. 37B  is a perspective view of an alternative embodiment of a marker for use in the delivery system of the present invention.  
       FIGS. 38-52  continue to illustrate a deployment sequence of the bifurcated endovascular stent graft of  FIG. 19 .  
       FIGS. 53-57  illustrate a number of alternative catheter distal shaft arrangements in which a well is provided to facilitate the orderly and tangle-free withdrawal of the release strand from the delivery catheter.  
       FIGS. 58-60  illustrate a further alternative belt support member and contralateral leg delivery system configurations and operation. 
    
    
     DETAILED DESCRIPTION  
       FIGS. 1-8  and  10  illustrate an embodiment of delivery system  10  for delivering a variety of expandable intracorporeal devices; specifically, an expandable endovascular graft  11 . One such expandable endovascular graft  11  useful for delivery and deployment at a desired site within a patient is disclosed in co-pending U.S. patent application Ser. No. 09/133,978, filed Aug. 14, 1998, by M. Chobotov, which is hereby incorporated by reference in its entirety.  
      Delivery system  10  in  FIG. 1  has an elongate shaft  12  with a proximal section  13 , a distal section  14 , a proximal end  15  and a distal end  16 . The distal section  14  has an elongate belt support member in the form of a guidewire tube  17  disposed adjacent a portion of the expandable endovascular graft  11 . A guidewire  18  is disposed within guidewire tube  17 . A plurality of belts  21 ,  22 , and  23  are secured to the guidewire tube  17  and are circumferentially disposed about portions of the endovascular graft  11 .  FIG. 1  shows the belts in a configuration that constrains the endovascular graft  11 . First and second release members  24  and  25  releasably secure belts  21 ,  22 , and  23  in a constraining configuration as shown.  
      The endovascular graft  11  has a proximal end  26 , a distal end  27 , a proximal inflatable cuff  28 , a distal inflatable cuff  30 , a proximal self-expanding member  31 , a first distal self-expanding member  32  and a second distal self-expanding member  33 . As defined herein, the proximal end of the elongate shaft is the end  15  proximal to an operator of the delivery system  10  during use. The distal end of the elongate shaft is the end  16  that enters and extends into the patient&#39;s body. The proximal and distal directions for the delivery system  10  and endovascular graft  11  loaded within the delivery system  10  as used herein are the same. This convention is used throughout the specification for the purposes of clarity, although other conventions are commonly used. For example, another useful convention defines the proximal end of an endovascular graft as that end of the graft that is proximal to the source of blood flow going into the graft. Such a convention is used in the previously discussed co-pending patent application Ser. No. 09/133,978, although that convention is not adopted herein.  
      The guidewire tube  17  has an inner lumen  34 , as shown in  FIG. 2 , a distal section  35 , a proximal end  36 , as shown in  FIG. 8 , and a distal end  37 . The inner lumen  34  of the guidewire tube  17  terminates at the distal end  37  with a distal guidewire tube port  38 , as shown in  FIG. 10 . As seen in  FIG. 8 , the proximal end  36  of guidewire tube  17  terminates in a port  41  disposed in the proximal adapter  42 . The port  41  is typically a tapered fitting such as a Luer lock fitting which facilitates the attachment of a hemostasis valve (not shown). The guidewire tube  17  is a hollow tubular member that normally has an annular cross section, although oval cross-sectional profiles and others are also suitable.  
      A portion of the distal section  35  of the guidewire tube  17 , shown in  FIG. 1 , is disposed within an inner lumen  43  of a distal nose piece  44 , as shown in  FIG. 5 . Distal nose piece  44  is configured in a streamlined bullet shape for easy passage within a patient lumen or vessel such as aorta  45 . Guidewire tube  17  may be bonded to the inner lumen  43  of the nose piece  44 , or it may be molded into the nose piece  44  during manufacture. Referring to  FIG. 1 , the nose piece  44  has a distal portion  46 , an intermediate portion  47  and a proximal shoulder portion  48  configured to slidingly engage the distal portion  51  of an inner lumen  52  of an outer tubular member  53 .  
      Referring to  FIGS. 1, 6A ,  6 B and  7 A, on the distal section  35  of guidewire tube  17 , proximal to the proximal shoulder portion  48  of nose piece  44 , a first distal belt  21  is secured to the guidewire tube  17 . The first distal belt may be secured to the guidewire tube  17  with any suitable adhesive such as cyanoacrylate, epoxy or the like. Both free ends  55  and  56  of the first distal belt  21  are secured to the guidewire tube  17 . The guidewire tube  17  may be made from a variety of suitable materials including polyethylene, teflon, polyimide and the like.  
      Referring to  FIGS. 2-5 , the inner lumen  34  of the guidewire tube  17  has an inside diameter that can accommodate a guidewire suitable for guiding a device such as delivery system  10 . The inner lumen  34  of the guidewire tube  17  may have an inside diameter of about 0.015 inch to about 0.045 inch; specifically, about 0.020 inch to about 0.040 inch. The outer diameter of the guidewire tube  17  may range from about 0.020 inch to about 0.060 inch; specifically, about 0.025 inch to about 0.045 inch.  
      Referring again to  FIGS. 6A, 6B  and  7 A, an optional first distal belt bushing  57  is disposed about the guidewire tube  17  so as to cover the portions of the free ends  55  and  56  of the first distal belt  21  that are secured to the distal section  35  of the guidewire tube  17 . This bushing  57  may also serve to control the constrained configuration of the belted self-expanding members, and may include geometric features to engage or support the belted members. A similar configuration is present at a second distal belt  22  which has free ends secured to the guidewire tube  17  proximal to the first distal belt  21 . A second distal belt bushing  63  is disposed about the guidewire tube  17  so as to cover the portions of the free ends of the second distal belt  22  that are secured to the guidewire tube  17 . A proximal belt  23  has free ends secured to the guidewire tube  17  proximal to the second distal belt  22  and has an optional proximal belt bushing  67 , as shown in  FIG. 6 , configured similarly to the first and second distal belt bushings  57  and  63 .  
      The belts  21 ,  22  and  23  can be made from any high strength, resilient material that can accommodate the tensile requirements of the belt members and remain flexible after being set in a constraining configuration. Typically, belts  21 ,  22  and  23  are made from solid ribbon or wire of a shape memory alloy such as nickel titanium or the like, although other metallic or polymeric materials are possible. Belts  21 ,  22  and  23  may also be made of braided metal filaments or braided or solid filaments of high strength synthetic fibers such as Dacron®, Spectra or the like. An outside transverse cross section of the belts  21 ,  22  and  23  may range from about 0.002 to about 0.012 inch, specifically, about 0.004 to about 0.007 inch. The cross sections of belts  21 ,  22  and  23  may generally take on any shape, including rectangular (in the case of a ribbon), circular, elliptical, square, etc.  
      In general, we have found that a ratio of a cross sectional area of the belts to a cross sectional area of the release members,  24  and  25 , of about 1:2 is useful to balance the relative strength and stiffness requirements. Other ratios, however, may also be used depending on the desired performance characteristics.  
      The inner diameters of belt bushings  57 ,  63  and  67  are sized to have a close fit over the guidewire tube  17  and secured portion  71 , as shown in  FIG. 7A , of the free ends of the belts  21 ,  22  and  23  that are secured to the guidewire tube  17 . Typically, the inner diameter of the belt bushings  57 ,  63  and  67  range from about 0.025 inch to about 0.065 inch; specifically, about 0.030 inch to about 0.050 inch. In addition, the outer diameter of belt bushing  57  may be sized to approximate an inner diameter  70 , as shown in  FIG. 4 , of the respective first distal self-expanding member  32  of the endovascular graft  11  when the member  32  is in a fully constrained state. The other belt bushings  63  and  67  may be similarly configured with respect to the second distal self-expanding member  33  and the proximal self-expanding member  31 .  
      Such an arrangement keeps the self-expanding members  31 ,  32  and  33  properly situated when in a constrained state and prevents the various portions of the self-expanding members  31 ,  32  and  33  from overlapping or otherwise entangling portions thereof while in a constrained state. The outer diameter of the belt bushings  57 ,  63  and  67  may range from about 0.040 inch to about 0.200 inch; specifically, about 0.060 inch to about 0.090 inch. The material of the belt bushings  57 ,  63  and  67  may be any suitable polymer, metal, alloy or the like that is bondable. Generally, the belt bushings  57 ,  63  and  67  are made from a polymer such as polyurethane, silicone rubber or PVC plastic.  
      As shown in  FIG. 7A , belts  21 ,  22  and  23  extend radially from the guidewire tube  17  through optional standoff tubes  72 ,  73  and  74 . Standoff tubes  72 ,  73  and  74  are disposed about belts  21 - 23  adjacent the guidewire tube  17  and act to prevent separation of belts  21 - 23  in a circumferential direction as tension is applied to the belts. Standoff tubes  72 - 74  also prevent belts  21 - 23  from applying other undesirable forces on portions of the endovascular graft  11  that are constrained by the belts. Specifically, the standoff tubes  72 - 74  prevent the belts  21 - 23  from spreading the self-expanding members  31 - 33 , or portions thereof, at those locations where the belts  21 - 23  extend radially through the self-expanding members.  
      The standoff tubes  72 - 74  typically have a length substantially equal to a single wall thickness of the self-expanding members  31 ,  32  and  33 . The length of the standoff tubes  72 - 74  may range from about 0.010 inch to about 0.030 inch. An inner diameter of an inner lumen  75  of the standoff tubes, as shown in  FIG. 4 , may range from about 0.004 to about 0.024 inch, with a wall thickness of the standoff tubes being about 0.002 inch to about 0.006 inch. Typically, the standoff tubes  72 - 74  are made from a high strength metal or alloy such as stainless steel, although they may be polymeric as well.  
      Belts  21 - 23  exit the outer apertures of standoff tubes  72 - 74  and extend circumferentially about the respective portions of the expandable intracorporeal device  11 . The term “circumferential extension” as used with regard to extension of the belts  21 - 23  is meant to encompass any extension of a belt in a circumferential direction. The belts may extend circumferentially a full 360 degrees, or any portion thereof. For example, belts or belt segments may extend partially about an endovascular device, and may be combined with other belts or belt segments that also partially extend circumferentially about an endovascular device. Typically, a plane formed by each of the belts  21 - 23  when in a constraining configuration is generally perpendicular to a longitudinal axis  76 , shown in  FIG. 1 , of the distal section  14  of shaft  12 . As shown in  FIGS. 6A and 6B , loop ends  81 ,  82  and  83  of the belts  21 ,  22  and  23 , respectively, are releasably locked together by one or more release members. For example, in the embodiment shown in  FIG. 1 , a release member in the form of a first release wire  24  is shown disposed within end loops  81  of the first distal belt  21  and end loops  82  of the second distal belt  22  so as to secure the first and second distal belts  21  and  22  in a constraining configuration about the endovascular graft  11 . Another release member in the form of a second release wire  25  is shown disposed within end loops  83  of the proximal belt  23  so as to secure the proximal belt  23  in a constraining configuration about the endovascular graft  11 .  
      A single release wire may also be used to perform the function of each of the first and second release wires,  24  and  25 , so that first distal belt  21 , second distal belt  22 , and proximal belt  23  may be releasably secured by a single release wire. A highly controlled, sequential belt deployment scheme may be realized with the use of a single release wire.  
      Any number of release wires and belts as may be needed to effectively secure and deploy graft  11 , in combination, are within the scope of the present invention.  
      In some embodiments of the invention, when constrained, the end loops of any single belt touch each other or are spaced closely together such that the belt as a whole forms a substantially circular constraint lying substantially in a plane. Release wire  24  and  25  may be made from suitable high strength materials such as a metal or alloy (e.g., stainless steel) which can accommodate the torque force applied to the release wire by the belt end loops  83  when the belts  23  are under tension from the outward radial force of the constrained portions of the endovascular graft  11 , i.e., the self-expanding members  32  and  33 .  
      The release wires  24  and  25  may generally have an outer diameter ranging from about 0.006 to about 0.014 inch. Distal end portions  84  and  85  of release wires  24  and  25 , respectively, may terminate at any appropriate site distal of the end loops  81 - 83  of belts  21 - 23 . As shown in  FIG. 8 , the proximal ends  86  and  87  of the release wires  24  and  25  extend through the elongate shaft  12  of the delivery system  10  through proximal ports  91  and  92  on the proximal adapter  42 , respectively, and terminate at respective release wire handles  93  and  94  which are releasably secured to the proximal adapter  42 .  
       FIG. 7B  illustrates an alternative embodiment of the belts  21 - 23  of  FIG. 7A . In  FIG. 7A , belts  21 - 23  are shown as each consisting of a single strand of wire formed into the end loops  81 - 83 , respectively, with the end loops in an overlapping configuration. Free ends  55  and  56  of belt  81  are shown secured to the distal section  35  of the guidewire tube  17 . In contrast,  FIG. 7B , wherein like elements with regard to  FIG. 7A  are shown with like reference numerals, shows belts  21 B,  22 B and  23 B formed of two strands of wire, with each strand formed into a single loop which overlaps a loop of the other strand to form end loops  81 B,  82 B and  83 B. The free ends of the belts  21 B- 23 B may be secured in a similar manner to those of free ends  55  and  56  of  FIG. 7A .  
      Turning now to  FIGS. 7C and 7D , alternative embodiments for portions of the delivery system of the present invention are shown.  FIGS. 7C and 7D  illustrate alternative belts  21 C,  22 C and  23 C disposed on guidewire tube  17 . Single or multiple belts  21 C- 23 C may be deployed at various locations along guidewire tube  17  as desired. In addition, the members comprising belts  21 C- 23 C are shown as a single line. However, belts  21 C- 23 C may be of a single- or multiple strand or filament design with various cross-sectional shapes as previously described. A single solid ribbon or wire is particularly useful.  
      Belts  21 C- 23 C shown in  FIGS. 7C and 7D  are a single strand filament wrapped around guidewire tube  17  and fixed thereon via any number of suitable techniques, such as gluing with adhesive, mechanical fixation, etc. Especially useful is fixing the belt with an ultraviolet-curable adhesive.  
      Alternatively, belts  21 C- 23 C may comprise two strand filaments each wrapped around guidewire tube  17  so that, for instance, belt  21 C is a two-filament component.  
      Belt  21 C includes belt arms  112  and  114 , each of which, in the embodiments shown, is a loop of filament twisted upon itself to form a helix. Any number of twists may be imparted to arms  112  and  114  to provide a relatively loose or relatively tight helix as desired. Typically the number of twists (with a single twist being defined as a single overlap of wire segment) in each belt arm  112  and  114  numbers from zero to about  50  or more; specifically, about two to about  10 . The choice of material used for belt  21 C is an important factor in determining the optimum number of twists for each belt arm. Belt arms  112  and  114  may be formed into other configurations (e.g., braid, double helix, etc.) as well.  
      Disposed within the end loops of the belt arms  112  and  114  are distal apertures or openings  120 ,  122 , respectively. During assembly of the delivery system, a release wire (such as wire  24 ) is passed through each aperture  120 ,  122  after the belt arms are wrapped around the graft self-expanding member, preferably in a circumferential groove as further described below. The release wire may also be disposed through any aperture created along the length of belt arms  112 ,  114  by each helix twist, although the distal-most apertures  120 ,  122  are preferred.  
      The wire optionally may be welded, glued, or otherwise fixed to itself at discrete points or along all or any portion of belt arms  112 ,  114 , save their corresponding apertures  120  and  122 . For instance, the belt arm wire may be glued or welded to itself at the overlap or twist points, such as points  124 .  
       FIG. 7D  shows an optional belt arm sleeve  126  that may be used to enclose a portion of one or both belt arms  112 ,  114 , or any of the other belt embodiments contemplated herein. Belt  112  is shown in  FIG. 7D  being constrained or covered over a length thereof by a flexible sleeve or coating  126  (or alternatively, a coil wrapping or by fixing the loop to itself by adhesives, welding, soldering, brazing, etc.). Sleeve or coating  126  may optionally be shrink-wrapped, crimped, or otherwise configured to constrain or cover belt arm  112  therein. These fixation and sleeve features help to minimize the potential of belt arm untwisting and tend to close or block some or all of the helix apertures along the length except those through which the release wire are intended to pass. They can also provide greater structural and operational stability to the catheter system as a whole.  
      Belt arm sleeve  126  can be configured to have a transverse dimension that is sized to fit a twisted belt arm with fixed nodal points such as the belt arm  112  shown in  FIG. 7D . In order to accommodate such a twisted belt arm  112 , the inner diameter and outer diameter would be large relative to a transverse dimension of the wire material that forms the belt arm  112 . However, the belt arm sleeve  126  can also be only slightly larger in transverse dimension that the wire that forms the belt arm. For example, embodiments of belt arms that do not have twisted wires may have a sleeve  126  that fits closely or tightly over two strands of wire forming a belt arm. The sleeve  126  can cover substantially the entire length of such an untwisted belt arm from at least the guidewire tube to just proximal of the distal loop, such as distal loop  120 . The distal loop should remain exposed for engagement by a release wire. In such an embodiment, the sleeve covered portion of the belt arm may also be wrapped around and secured to the guidewire tube just as the unsleeved belt portion of the belt arm  112  shown in  FIG. 7D  is shown at  71 C. This type of low profile belt arm sleeve may also be used to cover twisted belt arm embodiments, although a slightly larger diameter sleeve would be required.  
      It may be desirable to impart a particular free resting angle to the belt arms  112 ,  114  to improve the reliability of the system and further reduce the possibility of the arms  112  and  114  interfering with other components of the prosthesis or delivery system. The  FIG. 7C  view shows belt arms  112 ,  114  symmetrically disposed at an angle a as measured from a horizontal plane  125 . This angle a may range from zero to 180 degrees. For example, one or both belt arm  112 ,  114  may lie along plane  125  or they may rest in the configuration shown (α=45 degrees). Any known techniques may be used to impart a desired resting configuration to the system, such as, for example, cold working or shape-setting by way of an athermal phase transformation (in the case of shape memory alloys).  
       FIG. 7J  shows a single belt example of the version shown in  FIGS. 7C and 7D . Here, a single belt arm  113  is shown disposed about the distal end  35  of guidewire tube  17 . Belt arm  113  is significantly longer than either belt arm  112  or  114  of the  FIGS. 7C-7D  embodiment so that it may extend at least around the circumference of any one of self-expanding members  31 ,  32 , or  33 . The distal portion  115  of belt arm  113  meets a more proximal portion  117  where one or both strands (when the belt arm  113  is a twisted variety) extends through an end loop  119  in the belt arm  115  distal portion. As discussed with other embodiments, a release member such as release wire  24  may be inserted through end loop  119  and the intersecting portion of the belt arm proximal portion  117  to releasably secure belt arm  113  in a constraining configuration about the endovascular graft  11 .  FIG. 7K  depicts a simplified schematic cross-sectional view of belt arm  113  (shown here untwisted) held in place by a release wire  24  about an exemplary self-expanding member  32 .  FIG. 7L  is a detail of the connection formed where release wire  24  intersects the distal and proximal portions,  115  and  117 , respectively, of belt arm  113 .  
      All of the features discussed herein with respect to the  FIGS. 7C-7D  embodiment may be employed in the embodiment of  FIGS. 7J-7K  as well.  
      This helix configuration shown in the embodiments of  FIGS. 7C-7D  and  7 J- 7 L is a particularly reliable configuration. It reduces the possibility that a portion of belt  21 C becomes entangled with a self-expanding member (such as members  31 ,  32  and  33 ) or otherwise interferes with the safe and effective deployment of the prosthesis.  
       FIG. 7E  depicts a particularly useful arrangement for configuring the belt end loops  81 - 83  with release wires  24 - 25  during assembly of delivery system  10 . In this example, first and second end loops  81 ′ and  81 ″ of belt  21  are shown connected via release wire  24 . To achieve the configuration of  FIG. 7E , first end loop  81 ′ is passed through aperture  88  disposed in second end loop  81 ″. A portion of aperture  89  disposed in first end loop  81 ′ should extend through the plane created by second end loop  81 ″ as shown in  FIG. 7E .  
      Next, release wire  24  is passed through the portion of aperture  89  that extends beyond this plane so that wire  24  “locks” the two looped ends  81 ′ and  81 ″ together as shown. We have found that this is a stable configuration that lends itself well to a reliable and safe deployment protocol.  
      Other techniques for assembling wire  24  and first and second end loops  81 ′ and  81 ″ may be used; the method described above is merely exemplary. Wire  24  may simply pass through loop ends as configured and as shown at reference numerals  81 ,  82  and  83  in  FIG. 7A , and  81 B,  82 B and  83 B of  FIG. 7B  as well.  
      In the embodiment of  FIG. 7F , belt  110  is a member in the shape of a wire formed into an end loop  116 B having an aperture  120  for receiving a release wire. This arrangement may be used on one or both ends of belt  110  or, alone if belt  110  is in the form of a single belt arm as discussed above. Connection  123  is shown in  FIG. 7F  as a simple wrapping of the distal end  116 A of the wire comprising belt  110 . Connection  123  need not be limited to such a tapered or cylindrical sleeve or coating, however. Other methods to form end loop  116 B are contemplated, including, for example, the use of adhesives, welding, brazing, soldering, crimping, etc. An optional protective sleeve or coating  127  (shown in sectional view in  FIG. 7F ) covers or is part of connection  123  and serves to protect the patient as well as components of the delivery system and prosthesis from damage.  
      Turning now to  FIGS. 7G and 7H , two alternative embodiments of a ribbon-like belt  81 G and  81 H are shown. In  FIG. 7G , a section  128  of material has been partially displaced from belt  81 G distal end  116 C and worked into a loop-like member  129  such that two generally orthogonal apertures  130 ,  132  are formed in belt distal end  116 C. A set of hinges or other protective mechanism or material may be used on each end of this member  128  so that further tearing or peeling of this member may be prevented. Section  128  may be formed integrally from the belt distal end  116 C as shown in  FIG. 7G  or may be a separate component that is attached to the belt distal end by any suitable means.  
      Second belt distal end  118 C in  FIG. 7G  is shown as having an aperture  133  disposed therein. In use, a half-twist is imparted to the ribbon-like belt  81 G as the second distal end  118 C is brought through aperture  130  such that apertures  132  and  133  are at least partially aligned. A release wire (such as wire  24 ) is then brought through apertures  132  and  133  to releasably join ends  116 C and  118 C.  
       FIG. 7H  shows yet another embodiment of a belt  81 H where a simple rectangular aperture  133 A is disposed in the distal end  117  of belt  81 H through which another belt end and release wire may be disposed as taught herein. As with the embodiment of  FIG. 7G , a half-twist is imparted to the belt  81 H in use so that the second distal end  118 D is brought through aperture  133 . A release wire may then be threaded through apertures  132  and  133  to releasably join ends  117  and  118 D. In this embodiment, aperture  132  should be large enough to accommodate both second distal end  118 D and a release wire.  
       FIG. 7I  shows a perspective view of a belt assembly similar to that shown in  FIG. 7A , wherein like elements are shown with like reference numerals. An alternative embodiment of a release wire consisting of a branched release wire  150  is illustrated in  FIG. 7I . The branched release wire  150  engages belts  21 - 23  and is configured to release belts  21 - 23  at different times with a proximal withdrawal movement of the branched release wire  150 , the direction of which is indicated by arrow  151 . Branched release wire  150  has a main portion  152  and a branch portion  153 . Branch portion  153  is secured to main portion  152  by a solder joint  154 . The joint  154  could also be made by any other suitable means, such as welding, bonding with an epoxy, mechanically binding the joint, or the like. The embodiment of the branched release wire shown in  FIG. 7I  consists of wire which is generally round in cross section. The wire of the branched release wire can have the same or similar material and mechanical properties to the wire of the release wires  24  and  25  discussed above. Branch portion  153  engages first distal belt  21  and second distal belt  22 . A distal segment  155  has a length L indicated by arrow  156  which extends distally from first distal belt  21  to the distal end  157  of branch portion  153 .  
      Main portion  152  of the branched release wire  150  engages the proximal belt  23  and has a distal segment  158  that extends distally from the proximal belt  23  to a distal end  161  of the main portion. The length L′ of the distal segment  158  of the main portion  152  is indicated by arrow  162 . Length L of distal segment  155  is greater than length L′ of distal segment  158 . In this way, as the branched release wire is withdrawn proximally, proximal belt  23  is released first, first distal belt  21  is released second and second distal belt is released last. Such a branched release wire allows a wide variety of belt release timing with a single continuous withdrawal or movement of a proximal end (not shown) of the branched release wire  150 . The proximal end of the branched release wire may be terminated and secured to a release wire handle or the like, as discussed herein with regard to other embodiments of release wires. The ability to deploy multiple release wires in a desired timing sequence with a single branched release wire  150  gives the designer of the delivery system great flexibility and control over the deployment sequence while making the deployment of the belts simple and reliable for the operator of the delivery system. Although the branched release wire  150  has been shown with only a single branch, any number of branches or desired configuration could be used to achieve the deployment sequence required for a given embodiment of a delivery system. For example, a separate branch could be used for each belt in a multiple belt system, with varying distal segment length used to control the sequence of deployment. Also, multiple branched release wires, or the like, could be used in a single delivery system to achieve the desired results.  
      A number of embodiments for the belt and belt arm components of the present invention are described herein. In general, however, we contemplate any belt or belt arm configuration in which the belt may be used to releasably hold or restrain an implant member in conjunction with a release member. The particular embodiments disclosed herein are not meant to be limiting, and other variations not explicitly disclosed herein, such as those in which multiple apertures (which may have varying shapes and sizes) are disposed along the belt length, those in which the belt or belt arm distal ends comprises a separate material or element that is affixed to the belt or belt arm, etc. are within the scope of the invention. Furthermore, various embodiments of the ends of the belts or belt arms taught herein may exist in any combination in a single delivery system.  
      Turning now to  FIG. 6A , belts  21 - 23  lie within circumferential grooves or channels  95 ,  96  and  97 , respectively, formed into the respective self-expanding members  31 ,  32  and  33 . Grooves  95 - 97  prevent axial displacement of the belts  21 - 23  prior to activation or release of the releasable members  24  and  25 , i.e., proximal retraction of the first and second release wires. Although grooves  95 - 97  are illustrated in the embodiment shown, other alternatives are possible to achieve the same or similar function of the grooves. For example, abutments extending slightly from the self-expanding members  31 - 33  on either side of the belts  21 - 23  in their constraining configuration could prevent axial movement of the belts. A detachable adhesive or the like could also be used.  
      As shown in  FIG. 10 , the release of end loops  81 - 83  occurs when the distal end portions  84  and  85  of the release wires  24  and  25 , respectively, pass from within the overlapped end loops  81 - 83 . If the end loops  81 - 83  move axially in response to movement of the release wires  24  and  25  due to frictional forces imposed on the end loops  81 - 83  by the release wires, the point at which the distal ends of the release wires  84  and  85  pass from within the end loops  81 - 83  would vary depending on the amount of movement of the end loops  81 - 83 .  
      If the end loops  81 - 83  were to be axially displaced from their normal position relative to the distal ends of the release wires prior to deployment, the timing of the release of the belts  21 - 23  could be adversely affected. Thus, the prevention of axial displacement of the belts  21 - 23  during proximal retraction of the release wires  24  and  25  facilitates accurate release of the belts by keeping the overlap joint of the belt looped end portions in a constant axial position during such retraction.  
      In addition, it may be desirable to keep belts  21 - 23  positioned at or near the general center of a given constrained self-expanding members  31 - 33  so that the self-expanding member  31 - 33  is substantially uniformly and evenly constrained over its axial length. If belts  21 - 23  constrain the self-expanding members  31 - 33  at a non-centered axial position on the member, an end of the member opposite that of the non-centered position may be less constrained and may interfere with axial movement of the outer tubular member  53  (and consequently deployment of the endovascular graft  11 ).  
      Tubular body member  205  of the endovascular graft  11  is disposed between and secured to the second distal self-expanding member  33  and the proximal self-expanding member  31 . The tubular body member comprised of flexible material  204 , is shown constrained in an idealized view in  FIGS. 1, 3  and  6 , for clarity. In practice, tubular body member  205  while constrained is tightly compressed with minimal air space between layers of flexible material  204  so as to form a tightly packed configuration as shown in  FIG. 3 . Tubular body member  205  is optionally radially constrained by an inside surface  206  of the inner lumen  52  of outer tubular member  53 .  
      An inner tubular member  207  is slidably disposed within the inner lumen  52  of outer tubular member  53 . Release wires  24  and  25 , guidewire tube  17  and an inflation tube  211  are disposed within an inner lumen  212  of the inner tubular member  207 . Inner lumen  212  is optionally sealed with a sealing compound, depicted in  FIGS. 1, 2  and  6  by reference numeral  213  at distal end  214 . The sealing compound  213  prevents leakage of fluids such as blood, etc., from a proximal end  215 , shown in  FIG. 8 , of the inner tubular member  207 . Sealing compound  213  fills the space within the inner lumen  212  of the inner tubular member  207  between an outer surface  216  of the guidewire tube  17 , the outer surface  217  of the inflation tube  211  and outer surfaces  221  and  222  of a tubular guide  223  for the first release wire  24  and a tubular guide  224  for the second release wire  25 . The sealing compound  213  can be any suitable material, including epoxies, silicone sealer, ultraviolet cured polymers, or the like.  
      In  FIG. 2 , the tubular guides  223  and  224  for the first release wire  24  and the second release wire  25  allow axial movement of the release wires with respect to the sealing compound  213  and inner tubular member  207 . The inside diameter of the inner lumens of the tubular guides  223  and  224  are sized to fit closely with an outer diameter or transverse dimension of the release wires  24  and  25 . Alternatively, tubular guides  223  and  224  may be replaced by a single tubular guide that houses one or more release wires, such as wires  24  and  25 .  
      Turning to  FIG. 8 , the inner tubular member  207  terminates proximally with the proximal adapter  42  having a plurality of side arms  225 ,  226  and  227  and a proximal exit port  231  for the inner lumen  34  of the guidewire tube  17 . First release wire side arm  225  branches from a proximal adapter body portion  233  and has an inner lumen  234  and proximal end  86  of the first release wire  24 . A proximal extremity  236  of the first release wire  24  is anchored to the first release wire proximal handle  93  which is threaded onto the proximal end  238  of the first release wire side arm  225 . The proximal extremity  236  of first release wire  24  is configured as an expanded bushing or other abutment that captures the handle  93  and translates proximal axial movement of the handle  93  to the first release wire  24  but allows relative rotational movement between the handle  93  and the proximal end  86  of the first release wire  24 .  
      A similar configuration exists for the proximal end  87  of the second release wire  25 . There, a second release wire side arm  226  branches from the proximal adapter body portion  233  and has an inner lumen  244  that houses the proximal end  87  of the second release wire  25  which is free to slide in an axial orientation within the lumen  244 . A proximal extremity  246  of the second release wire  25  is configured as an expanded bushing or other abutment that captures the second release wire handle and translates axial proximal movement of the second release wire handle  94  to the second release wire  25 , but allows relative rotational movement between the proximal end  87  of the second release wire  25  and the second release wire handle  94 .  
      The first release wire handle  93  and second release wire handle  94  may optionally be color coded by making each, or at least two, release wire handles a color that is distinctly different from the other. For example, the first release wire handle  93  could be made green in color with the second release wire handle  94  being red in color. This configuration allows the operator to quickly distinguish between the two release wire handles and facilitates deployment of the belts in the desired order.  
      In another embodiment, instead of color coding of the release wire handles  93  and  94 , the spatial location of the handles can be configured to convey the proper order of deployment of the release wires to the operator of the delivery system. For example, if three release wire handles are required for a particular embodiment, the corresponding three side arms can be positioned along one side of the proximal adapter. In this configuration, the release wire handle that needs to be deployed first can extend from the distal-most side arm. The release wire handle that needs to be deployed second can extend from the middle side arm. The release wire handle that is to be deployed last can extend from the proximal-most side arm. For such a configuration, the operator is merely instructed to start deployment of the release wires at the distal-most release wire handle and work backward in a proximal direction to each adjacent release wire handle until all are deployed. Of course, an opposite or any other suitable configuration could be adopted. The configuration should adopt some type of spatially linear deployment order, either from distal to proximal or proximal to distal, in order to make reliable deployment of the release wires in the proper order easy to understand and repeat for the operator of the delivery system. Other types of release order indicators such as those discussed above could also be used, such as numbering each release wire handle or side arm with a number that indicates the order in which that handle is to be deployed.  
      The proximal end  36  of the guidewire tube  17  terminates and is secured to an inner lumen  251  of the proximal end  259  of the proximal adapter  42 . Inner lumen  251  typically has a longitudinal axis  253  that is aligned with a longitudinal axis  254  of the proximal section  13  elongate shaft  12  so as to allow a guidewire to exit the proximal end  15  of the elongate shaft  12  without undergoing bending which could create frictional resistance to axial movement of the guidewire. A proximal port  255  of the proximal adapter  42  may be directly fitted with a hemostasis valve, or it may be fitted with a Luer lock fitting which can accept a hemostasis valve or the like (not shown).  
      The proximal adapter  42  may be secured to the proximal end  215  of the inner tubular member  207  by adhesive bonding or other suitable method. A strain relief member  256  is secured to the distal end  257  of the proximal adapter  42  and the inner tubular member  207  to prevent kinking or distortion of the inner tubular member  207  at the joint.  
      As seen in  FIG. 1 , the proximal end  261  of the outer tubular member  53  is secured to a proximal fitting  262  that slides over an outer surface  258  of the inner tubular member  207 . A seal  263  located in proximal fitting  262  provides a fluid seal for the lumen  265  formed between the outer surface  258  of the inner tubular member  207  and the inner surface  206  of the inner lumen  52  of the outer tubular member  53 . The fit between the outer surface  258  of the inner tubular member  207  and the inner surface  206  of the outer tubular member  53  is typically close, but still allows for easy relative axial movement between outer tubular member  53  and inner tubular member  207 . A stop  266  is disposed and secured to the outer surface  258  of the inner tubular member  207  distal of the proximal adapter  42  to limit the amount of proximal axial movement of the outer tubular member  53  relative to the inner tubular member  207 .  
      When the outer tubular member  53  is positioned on the proximal shoulder  48  of the distal nose piece  44  prior to deployment of endovascular graft  11 , the distance between a proximal extremity  267  of proximal fitting  262  and a distal extremity  268  of stop  266  is approximately equal to or slightly greater than an axial length of the endovascular graft  11  in a constrained state. This configuration allows the outer tubular member  53  to be proximally retracted to fully expose the endovascular graft  11  in a constrained state prior to deployment of the graft. This distance may be greater, but should not be less than the length of the endovascular graft  11  in a constrained state in order to completely free the constrained graft  11  for radial expansion and deployment.  
      Retraction limiters may alternatively be used to prevent excessive axial movement of the release wires  24  and  25  in a proximal direction during deployment. Particularly in embodiments of the invention where single release wires are used to constrain and deploy multiple belts such as with first release wire  24 , retraction limiters may be used to allow enough axial movement of the release wire  24  to deploy a first belt  21 , but prevent deployment of a second more proximally located belt  22 . For example, as shown in  FIG. 8 , a retraction limiter in the form of a filament  268  could be disposed between the proximal adapter  42  and the handle  93  of the first release wire  24  such that proximal retraction of the first release wire  24  sufficient for deployment of the first distal belt  21  could be achieved, but not so much as to allow deployment of the second distal belt  22 . In order to deploy the second distal belt  22 , the filament  268  would have to be severed or otherwise released. This type of configuration can allow more control over deployment of the endovascular graft  11  and allow deployment in stages which are sequentially controlled to prevent inadvertent deployment of a portion of the graft  11  in an undesirable location within the patient&#39;s vessels.  
      In use, the delivery system  10  is advanced into a patient&#39;s arterial system  271  percutaneously as shown in  FIG. 9  and positioned so that the endovascular graft  11  spans an aneurysm  272  in the patient&#39;s aorta  45  as illustrated in  FIGS. 1 and 9 - 12 . It is generally desirable to have the tubular body portion  205  of the graft  11  positioned below the renal arteries  273  in order to prevent significant occlusion of the renal arteries. The procedure typically begins with the placement of guidewire  18  into the patient&#39;s target vessel  45  across the target location, e.g., the aneurysm  272 . Common percutaneous techniques known in the art may be used for the initial placement of the guidewire  18 . For example, as shown in  FIG. 9 , percutaneous access to the aorta may be had through the femoral or iliac artery, although other access sites may be used. The delivery system  10  may then be advanced over the guidewire  18  to a desired position within the patient&#39;s vessel  45 . Alternatively, delivery system  10  and guidewire  18  could be advanced together into the patient&#39;s vasculature  272  with the guidewire  18  extending distally from the distal port  38  of the guidewire tube  17 . In addition, it may be desirable in some cases to advance the delivery system  10  to a desired location within the patient without the use of a guidewire  18 .  
      Generally, the position of the delivery system  10  is determined using fluoroscopic imaging or the like. As such, it may be desirable to have one or more radiopaque markers (not shown) secured to the delivery system at various locations. For example, markers may be placed longitudinally coextensive with the respective distal and proximal extremities  274  and  275 , as shown in  FIG. 11 . In this way, it can be readily determined whether the graft  11  is spanning the aneurysm  272  of the patient&#39;s artery. Imaging markers, such as radiopaque markers, may also be secured to desirable positions on the endovascular graft  11  itself. Other types of imaging and marking systems may be used such as computed tomography (CT), magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) imaging systems and markers.  
      Once the distal section  14  of the delivery system  10  is properly positioned within the patient&#39;s artery  45 , the operator moves the proximal end  261  of outer tubular member  53  in a proximal direction relative to inner tubular member  207 . The relative axial movement is carried out by grasping the proximal end  215  of the inner tubular member  207  or proximal adapter  42 , and grasping the proximal end  261  of the outer tubular member  53 , and moving the respective proximal ends towards each other. This retracts the distal section  276  of the outer tubular member  53  from the constrained endovascular graft  11  and frees the graft for outward radial expansion and deployment. However, in this deployment scheme, note that the operator is free to reinsert graft  11  back into the outer tubular member  53  if necessary, as the release bands have not yet released the graft.  
      Once the distal section  276  of the outer tubular member  53  has been retracted, handle  93  of the first release wire  24  may then be unscrewed or otherwise freed from the proximal adapter  42  and retracted in a proximal direction indicated by arrow  279  in  FIG. 10  until the distal end  84  of the first release wire  24  passes from within the end loops  81  of the first distal belt  21 . When this occurs, the looped ends  81  of the first distal belt  21  are released and the first distal belt  21  ceases to radially constrain the first distal self-expanding member  32  which thereafter self-expands in a radial direction into an inner surface  278  of the patient&#39;s aorta  45  as shown in  FIG. 10 .  
      If the operator of the delivery system  10  is not satisfied with the position, particularly the axial position, of the endovascular graft  11  after deployment of the first distal self-expanding member  32 , it may then be possible to re-position the endovascular graft  11  by manipulating the proximal end  15  of the elongate shaft  15 . Movement of the elongate shaft  12  can move the endovascular graft  11 , even though physical contact between the expanded member  32  and the vessel inner surface  278  generates some static frictional forces that resist such movement. It has been found that the endovascular graft  11  can be safely moved within a blood vessel  45  even in the state of partial deployment discussed above, if necessary.  
      Once the operator is satisfied with the position of the graft  11 , the first release wire  24  may then be further proximally retracted so as to deploy the second distal belt  22  in a manner similar to the deployment of the first distal belt  21 . The deployment of the second distal belt  22  occurs when the distal end  84  of the first release wire  24  passes from within end loops  82  of the second distal belt  22  which are held in a radially constraining configuration by the first release wire  24 . Upon release of the second distal belt  22 , the second distal self-expanding member  33  expands in a radial direction such that it may engage inner surface  278  of the patient&#39;s aorta  45 . The amount of outward radial force exerted by the self-expanding members  32  and  33  on the inside surface  278  of the patient&#39;s aorta  45 , which may vary between members  32  and  33 , is dependent upon a number of parameters such as the thickness of the material which comprises the self-expanding members  32  and  33 , the nominal diameter which the self-expanding members  32  and  33  would assume in a free unconstrained state with no inward radial force applied, material properties of the members and other factors as well.  
      Once the distal members  32  and  33  are deployed, the handle  94  for the second release wire  25  can be disengaged and axially retracted in a proximal direction from the proximal adapter  42  until the distal end  85  of the second release wire  25  passes from within the end loops  83  of the proximal belt  23 . Once the proximal belt  23  is released, the proximal self-expanding member  31  is deployed and expands in an outward radial direction, such that it may engage or be in apposition with the inner surface  278  of the patient&#39;s aorta  45  as shown in  FIG. 11 . Thereafter, the endovascular graft  11  may be inflated with an inflation material (not shown) introduced into the proximal injection port  282  in the proximal adapter  42 , through the inflation tube  211 , and into the inflation port  283  of the endovascular graft  11 . Inflation material may be injected or introduced into the inflation port  283  until the proximal and distal inflatable cuffs  28  and  30  and inflatable channels  284  of the graft  11  have been filled to a sufficient level to meet sealing and other structural requirements necessary for the tubular body to meet clinical performance criteria.  
      Before or during the deployment process, and preferably prior to or simultaneous with the step of inflating the endovascular graft  11 , it may be beneficial to optionally treat vessel  45  in which the graft  11  is deployed so to obtain a better seal between the graft  11  and the vessel inner surface  278 , thus improving the clinical result and helping to ensure a long term cure.  
      One approach to this treatment is to administer a vasodilator, or spasmolytic, to the patient prior to deploying graft  11 . This has the effect of reducing the tone of the smooth muscle tissue in the patient&#39;s arteries; specifically, the smooth muscle tissue in the wall of vessel  45  into which graft  11  is to be deployed. Such tone reduction in turn induces the dilation of vessel  45 , reducing the patient&#39;s blood pressure. Any number of appropriate vasoactive antagonists, including the direct acting organic nitrates (e.g., nitroglycerin, isosorbide dinitrate, nitroprusside), calcium channel blocking agents (e.g., nifedipine), angiotensin-converting enzyme inhibitors (e.g., captopril), alpha-adrenergic blockers (e.g., phenoxybenzamine, phentolamine, prasozin), beta-adrenergic blockers (e.g., esmolol) and other drugs may be used as appropriate. Particularly useful are those vasodilators that can be administered intravenously and that do not have unacceptable contraindications such as aoritic aneurysm dissection, tachycardia, arrhythmia, etc.  
      The degree of vasodilatation and hypotensive effect will depend in part on the particular vessel in which graft  11  is to be placed and the amount of smooth muscle cell content. Generally, the smaller the vessel, the larger percentage of smooth muscle cell present and thus the larger effect the vasodilator will have in dilating the vessel. Other factors that will effect the degree of vasodilatation is the health of the patient; in particular, the condition of the vessel  11  into which graft  11  is to be placed.  
      In practice, once the vasodilator has been administered to the patient, graft  11  may be deployed and filled with inflation material so that graft  11  reaches a larger diameter than would otherwise be possible if such a vasodilator was not used. This allows the inflation material to expand the diameter of graft  11 , for a given inflation pressure, beyond that which would be achievable if the vessel  45  were in a non-dilated state (and nominal diameter). Alternatively, a larger diameter graft  11  may be chosen for deployment. We anticipate that an increased vessel diameter of between two and twenty percent during vasodilatation may be optimal for achieving an improved seal.  
      The vessel  45  in which graft  11  is to be placed may optionally be monitored pre- and/or post-dilation but before deployment of graft  11  (via computed tomography, magnetic resonance, intravenous ultrasound, angiography, blood pressure, etc.) so to measure the degree of vasodilatation or simply to confirm that the vasodilator has acted on the vessel  45  prior to deploying graft  11 .  
      Once the vasodilator wears off, preferably after between about five and thirty minutes from the time the drug is administered, the vessel  45  surrounding graft  11  returns to its normal diameter. The resultant graft-vessel configuration now contains an enhanced seal between graft  11  and vessel inner surface  278  and provides for reduced luminal intrusion by graft  11 , presenting an improved barrier against leakage and perigraft blood flow compared to that obtainable without the sue of vasodilators or the like.  
      Such vasodilating techniques may be used with all of the embodiments of the present invention, including the tubular graft  11  as well as a bifurcated graft version of the expandable intracorporeal device of the present invention as is discussed in detail below.  
      Once graft  11  is fully deployed, a restraining or retention device, such as retention wire  285  that binds the distal end  286  of the inflation tube  111  to the inflation port  283 , as shown in  FIGS. 12 and 13 , is activated. The retention wire  185  is activated by pulling the proximal end of the wire in a proximal direction so as to disengage the distal ends  293  and  294  from the holes  295  and  296 . This eliminates the shear pin function of the distal ends  293  and  294  and allows the distal end  286  of the inflation tube  211  to be disengaged from the inflation port  283 . The release wires  24  and  25  may then be fully retracted from the elongate shaft  12  in a proximal direction and the delivery system  10  retracted in a proximal direction from the deployed endovascular graft  11 . The unconstrained distal belts  21 - 23  slip through the openings in the expanded members  31 ,  32  and  33  as the delivery system  10  is retracted and are withdrawn through the inner passageway  287  of the deployed graft  11 . The distal nosepiece  44  is also withdrawn through the inner passageway  287  of the deployed graft  11  as the delivery system  10  is withdrawn as shown in  FIG. 10-12 .  
       FIG. 13  illustrates the junction between the distal end  286  of inflation tube  211  and inflation port  283 . Typically, retention wire  285  extends from the inflation port  283  proximally to the proximal end  15  of delivery system  10 . In this way, an operator can disengage the distal end  286  of the inflation tube  211  from the inflation port  283  by pulling on the proximal end  283  of retention wire  285  from a proximal end  15  of delivery system  10 . The retention wire  285  can be a small diameter wire made from a material such as a polymer, stainless steel, nickel titanium, or other alloy or metal; in a particular embodiment of the invention, retention wire  285  may be a spring formed of a variety of suitable spring materials. Alternatively retention wire  285  may have a braided or stranded configuration.  
       FIG. 13  shows a single retention filament or wire  285  disposed within the lumen  291  of the inflation tube  211 . The distal end  292  of retention wire  285  may have one or more loops  293  and  294 , respectively, disposed within one or more side holes disposed in the inflation port  283  of the distal end  286  of the inflation tube  211 . A number of side hole configurations may be utilized. The embodiment of  FIG. 13  has two sets of opposed side hole locations  295  and  296 . The distal loops  293  and  294  of the retention wire  285  act to interlock the side holes  295  and  296  by creating a removable shear pin element which prevents relative axial movement between the distal end  286  of the inflation tube  211  and the inflation port  283 . Alternate embodiments may include multiple retention filaments or wires disposed within the lumen  291  of the inflation tube  211 . An external sleeve (not shown) may be added over this assembly to further secure the interface and prevent leakage of inflation material through side holes  295  and  296 . This sleeve is attached to inflation tube  211  and is received with it.  
       FIGS. 14-17  illustrate an alternative embodiment of the delivery system shown in  FIG. 1 . In  FIGS. 14-17 , like elements with respect to the embodiment of  FIG. 1  will be shown with like reference numerals where appropriate. The delivery system  300  has an outer tubular member  53  and inner tubular member  207  at a distal section  303  of the delivery system  300 . An endovascular graft  11  is disposed within the outer tubular member in the distal section  303 . An inflation tube  305 , similar to that of the embodiment shown in  FIG. 1  is coupled to an inflation port  283  of the endovascular graft  11 . However, the inflation tube  305 , having a proximal end  307  and a distal end  308 , does not extend the majority of the length of the delivery system  300 . Instead, the proximal end  307  of the inflation tube  305  terminates at a proximal end  311  of the potted section  213  as shown in  FIGS. 14-16 .  
      Referring to  FIG. 14  and  16 , first release wire  312  having distal end  313  engages end loops  82  of second distal belt  22 . The second distal belt  22  is disposed about and constrains the second distal self-expanding member  33 . A second release wire  316  having a distal end  317  engages the end loops  81  of the first distal belt  21  and the end loops  83  of the proximal belt  23 . The first distal belt  21  is disposed about and constrains the first distal self-expanding member  32 . The proximal belt  23  is disposed about and constrains the proximal self-expanding member  31 . A release wire tube  318 , having a proximal end  321 , as shown in  FIG. 17 , and a distal end  322 , shown in  FIG. 16 , extends from the potted section  213  of the distal section  303  of the delivery system  300  to the proximal adapter  323  shown in  FIG. 17 . The release wire tube  318  has a lumen  324 , as shown in  FIG. 15 , which contains the first release wire  312  and the second release wire  316 .  
      The proximal adapter  323  has a first side arm  324  with an inner lumen  325  that secures the proximal end  321  of the release wire tube  318 . A threaded end cap  326  is secured to a proximal end  327  of the first side arm  324  and has a threaded portion  328 . A second release wire handle  331 , having a distal threaded portion  332  and a proximal threaded portion  333 , is threaded onto the threaded end cap  326 . A proximal end  334  of the second release wire  316  is secured to the second release wire handle  331 . A first release wire handle  335  has a threaded portion  336  that is releasably threaded onto the proximal threaded portion  333  of the second release wire handle  331 . A proximal end  337  of the first release wire  312  is secured to the first release wire handle  335 .  
      Once the outer tubular member  53  has been proximally retracted, belts  21 - 23  can be released. This configuration allows the operator of the delivery system  300  to first disengage and proximally retract the first release wire handle  335  so as to first release the second distal self-expanding member  33  without releasing or otherwise disturbing the constrained state of the first distal self-expanding member  32  or the proximal self-expanding member  31 . Once the second distal self-expanding member  33  has been deployed or released, the endovascular graft  11  may be axially moved or repositioned to allow the operator to adjust the position of the graft  11  for final deployment.  
      This is advantageous, particularly in the treatment of abdominal aortic aneurysms, because it allows the physician to accurately place graft  11  into position. In many cases, it is desirable for the physician to place the graft  11  such that the distal end of the tubular body portion  205  of the graft is just below the renal arteries  273 , shown in  FIG. 9 , to prevent occlusion of the renal arteries by the tubular body portion  205 . If a self-expanding member, such as self-expanding member  32  is radiopaque and the delivery procedure is performed using fluoroscopic imaging, adjustment of the position of the graft after release of self-expanding member is readily achievable. Because self-expanding member  32  is immediately adjacent the distal end of the tubular body portion  205  of the graft  11 , the ability to visualize and reposition the self-expanding member  32  is particularly useful in order to position the distal end of the tubular body portion  205  just below the renal arteries without occluding the renal arteries, if such positioning is indicated for the patient being treated.  
      Thereafter, the second release wire handle  331  may be unscrewed or otherwise released from the end cap  326  and proximally retracted so as to first release the first distal belt end loops  81  and then the proximal belt end loops  83 . Of course, the position of the graft  11  may still be adjustable even with both distal self-expanding members  32  and  33  deployed, depending on the particular configuration of the graft  11  and the self-expanding members  32  and  33 . The release of the belts  21 ,  22  and  23  is the same or similar to that of the belts of the embodiment of  FIG. 1  and occurs when the distal end of the release wires  313  and  317  which lock the end loops  81 - 83  together is proximally retracted past the end loops  81 - 83  of the belts  21 - 23  which are constrained.  
      Once the self-expanding members  31 - 33  of the endovascular graft  11  have been deployed or released, and the graft  11  is in a desired location, the graft  11  can then be inflated by injection of an inflation material (not shown) into the injection port  338  on a second side arm  341  of the proximal adapter  323 . The inflation material is introduced or injected directly into an inner lumen  212  of the inner tubular member  207 , as shown in  FIG. 17 , and travels distally between an inside surface  342  of the inner tubular member  207 , outside surface  343  of the release wire tube  318  and outside surface  216  of the guidewire tube  17 . This allows the inflation material, which can be highly viscous, to flow through the cross sectional area between the inside surface  342  of the inner tubular member  207  and the outside surfaces  216  and  343  of the release wire tube  318  and guidewire tube  17 . This cross sectional area is large relative to the cross sectional area of the inner lumen of the inflation tube  211  of the embodiment of  FIG. 1 . This results in more rapid flow of inflation material to the inflatable cuffs  28  and  30  and channels  284  of the endovascular graft  11  and decreases inflation time.  
      Once the inflation material, which is travelling distally in the delivery system  300  during inflation, reaches the potted portion  213  of the distal section  303  of the delivery system, it then enters and flows through a lumen  344 , as shown in  FIG. 16 , at the proximal end  307  of the inflation tube  305  and into the inflation port  283  of the graft  11 . Upon inflation of the graft  11  with an inflation material, a release device, such as retention wire  285  can be retracted or otherwise activated so as to de-couple the inflation tube  305  from the inflation port  283  of the endovascular graft  11 .  
      A proximal end  36  of the guidewire tube  17  is secured within a central arm  345  of the proximal adapter  323  that has a potted section  346 . A seal  349  is disposed on a proximal end  347  of the central arm  345  for sealing around the guidewire  18  and preventing a backflow of blood around the guidewire. A hemostasis adapter (not shown) can be coupled to the proximal end  347  of the central arm  345  in order to introduce fluids through the guidewire tube lumen  348 , as shown in  FIG. 15 , around an outside surface of the guidewire  18 . The potted section  346  of the central arm  345  prevents any fluids injected through the hemostatis adapter from passing into the inflation material lumen  351  within the proximal adapter  323  or the inner tubular member  207 .  
       FIG. 18  illustrates an alternative embodiment to the proximal adapters  42  and  323  used in the embodiments of the invention of  FIG. 1  and  FIG. 14 . In this embodiment, the proximal adapter  360  has a first release wire handle  361  and a second release wire handle  362  which are in a nested configuration. The proximal end  334  of the second release wire  316  is secured to the second release wire handle  362 . The proximal end  337  of the first release wire  312  is secured to the first release wire handle  361 . This configuration prevents the operator from inadvertently deploying or activating the second release wire  316  prior to deployment or activation of the first release wire  312  which could result in an undesirable endovascular graft deployment sequence.  
      In use, the operator first unscrews or otherwise detaches a threaded portion  363  of the first release wire handle  361  from an outer threaded portion  364  of a first side arm end cap  365  of a first side arm  366 . The first release wire handle  361  is then proximally retracted which releases the end loops  82  of the second distal belt  22  as discussed above with regard to the embodiment of the invention shown in  FIG. 14 .  
      Once the first release wire handle  361  is removed from the first side arm end cap  365 , the second release wire handle  362  is exposed and accessible to the operator of the delivery system. A threaded portion  367  of the second release wire handle  362  can then be unscrewed or otherwise detached from an inner threaded portion  368  of the first side arm end cap  365 . The second release wire handle  362  can then be retracted proximally so as to sequentially deploy the first distal belt  21  and self-expanding member  32  and proximal belt  23  and proximal self-expanding member  31 , respectively. The other functions and features of the proximal adapter  360  can be the same or similar to those of the proximal adapters  42  and  323  shown in  FIG. 1  and  FIG. 17  and discussed above.  
      Optionally, this embodiment may comprise reverse or oppositely threaded portions,  363  and  367  respectively, of the first and second release wire handles  361  and  362 . Thus, for instance, a counter-clockwise motion may be required to unthread threaded portion  363  of the first release wire handle  361  from the outer threaded portion  364 , while a clockwise motion is in contrast required to unthread threaded portion  367  of the second release wire handle  367  from the inner threaded portion  368 . This feature serves as a check on the overzealous operator who might otherwise prematurely unscrew or detach the threaded portion  367  of the second release wire handle  362  by unscrewing in the same direction as required to release the threaded portion  363  of the first release wire handle  361 .  
      In another aspect of the invention, a delivery system  400  for delivery and deployment of a bifurcated intracorporeal device, specifically, an embodiment of the invention directed to delivery and deployment of a bifurcated endovascular graft or stent is contemplated. As with all the delivery systems disclosed herein, the delivery system  400  for a bifurcated device is configured for delivery and deployment a wide variety of intracorporeal devices. Although the focus of the specific embodiments are directed to systems for delivery of endovascular grafts or stent grafts, embodiments of the delivery systems disclosed herein can are also suitable for delivery of intravascular filters, stents, including coronary stents, other types of shunts for intracorporeal channels, aneurysm or vessel occluding devices and the like.  
      The structure, materials and dimensions of the delivery system  400  for bifurcated devices can be the same or similar to the structure, materials and dimensions of the delivery systems discussed above. In addition, the structure, materials and dimensions of bifurcated grafts contemplated herein can have structure, materials and dimensions similar to those of grafts having a primarily tubular shape discussed above.  
       FIGS. 19-22  illustrate an embodiment of an expandable intracorporeal device in the form of a bifurcated stent-graft  401 . This embodiment includes a main body portion  402  at a distal end  403  of the graft  401  that has a generally tubular cross-sectional profile when the graft takes on an expanded or deployed configuration. An ipsilateral leg  404  and contralateral leg  405  (short leg), both having a substantially tubular configuration when expanded or deployed, branch from the main body portion  402  at bifurcation  406  and extend in a proximal direction from the bifurcation  406 . The ipsilateral leg  404  terminates proximally with a proximal self-expanding member  407  and the contralateral leg  405  terminates proximally with a proximal self-expanding member  408 .  
      The main body portion  402  of the graft may have a transverse dimension when in an expanded or deployed state ranging from about 10 mm to about 40 mm, specifically from about 15 mm to about 30 mm. The legs  404  and  405  of the graft  401  may have a transverse dimension when in an expanded or deployed state ranging from about 5 mm to about 16 mm, specifically from about 8 mm to about 14 mm. The main body portion  402  of the graft  401  may have a length ranging from about 2 cm to about 12 cm, specifically from about 4 cm to about 8 cm.  
      A second distal self-expanding member  411  is disposed at a distal end  412  of the main body portion  402  of the graft  401  as with the graft embodiments previously discussed. Also, as with other endovascular graft embodiments discussed herein, the graft  401  may have inflatable channels and inflatable cuffs that serve, among other functions, to provide support for the graft  401  and the inflatable channels and cuffs can have configurations which are the same or similar to those inflatable channels and cuffs of other graft embodiments discussed herein, as well as other configurations. A distal inflatable cuff  413  is disposed at the distal end  412  of the main body portion  402 . Proximal inflatable cuffs  414  and  415  are disposed on a proximal end  416  of the ipsilateral leg  404  and a proximal end  417  of the contralateral leg  405  respectively. Inflatable channels  418  are fluid tight conduits which connect the inflatable cuffs  413 ,  414  and  415 . The inflatable channels  418  and inflatable cuffs  413  and  414  are inflatable through an inflation port  421  that may be disposed at or near the proximal end  416  of the ipsilateral leg  404 . The inflation port  421  may also be disposed at or near the proximal end  417  of the contralateral leg  405 , or it may be disposed on other portions of the device as necessary. Generally, the structure and the materials used in the graft  401  (both the graft portion and the self-expanding members) can be similar to the structure and materials of the other graft embodiments discussed above. In one particular embodiment, the main body portion and legs of the graft are made of expanded polytetrafluoroethylene (ePTFE) and the self-expanding members are made of nickel titanium, stainless steel or the like.  
      A first distal self-expanding member  422  is secured to the second distal self-expanding member  411  as shown in  FIG. 19 . This configuration is similar to that of endovascular graft  11  illustrated in  FIGS. 1-6B ,  10 - 12  and  14 - 16  above. Graft  11  has first and second distal self-expanding members  32  and  33  that may be deployed in any desired sequence. In a particular embodiment having first and second distal self-expanding members, it may be desirable to first deploy the second distal self-expanding member  33  prior to deploying the first distal self-expanding member  32 . As discussed above, deploying the second distal self-expanding member  33  first may allow the operator to accurately adjust the axial position of the graft in the body lumen or vessel to within one to several millimeters before deploying the first distal self-expanding member  32 . Using this technique, deployment of the second distal self-expanding member  33  alone provides sufficient resistance to axial displacement of the graft  11  for the graft position to be maintained in normal blood flow, but still allows deliberate axial displacement by the operator to achieve a desired axial position. This may be particularly important if tissue-penetrating members are included on the distal-most or first distal self-expanding member  32 . If such tissue penetrating members are used on the first distal self-expanding member  32 , axial movement may be difficult or even impossible once this member  32  is deployed without risking damage to the body lumen or vessel. As such, accurate axial placement of the graft  11  prior to deployment of the first distal self-expanding member  32  can be critical.  
      In addition, although not shown in the figures, this graft embodiment  401  may include two or more proximal self-expanding members disposed on one or both of the ipsilateral leg  404  and/or contralateral leg  405 . These self-expanding members may have a configuration similar to that of the first and second distal self-expanding members  411  and  422   
       FIGS. 23-32  illustrate an embodiment of a delivery system  400  having features of the invention.  FIG. 23  shows delivery system  400  in partial section having an elongate shaft  423  with a proximal end  424 , a distal end  425  and a distal section  426 . A proximal adapter  427  is disposed at the proximal end  424  of the elongate shaft  423  and houses the controls that enable the operator to manipulate elements at the distal section  426  of delivery system  400  to release and deploy the graft  401 , including inflating the graft channels  418  and cuffs  413 ,  414  and  415 . The elongate shaft  423  has an inner tubular member  430  and an outer tubular member  431  disposed about the inner tubular member  430 . The outer tubular member  431  is generally configured to slide in an axial direction over the inner tubular member  430 . A proximal end  432  of the inner tubular member  430  is secured to or disposed on the proximal adapter  427 . The inner and outer tubular members  430  and  431  may be made of polymeric materials, e.g., polyimides, polyester elastomers (HYTREL®), or polyether block amides (PEBAX®), and other thermoplastics and polymers. The outside diameter of the outer tubular member  431  may range from about 0.1 inch to about 0.4 inch; specifically from about 0.15 inch to about 0.20 inch. The wall thickness of the outer tubular member  431  may range from about 0.002 inch to about 0.015 inch, specifically from about 0.004 inch to about 0.008 inch. The proximal adapter  427  is generally fabricated from a polymeric material such as polyethylene, acetal resins (DELRIN®), etc., but can also be made from any other suitable material.  
      Bifurcated stent graft  401  is shown in  FIGS. 23-28  disposed within the distal section  426  of the elongate shaft  423  in a constrained configuration. The outer tubular member  431  is disposed about the graft  401  in the constrained state but can be retracted proximally so as to expose the constrained graft  401  by proximally retracting a proximal end  433  of the outer tubular member  431 . As illustrated more fully in  FIG. 37 , a distal nosepiece  434  may be disposed on a distal end  435  of the outer tubular member  431  and forms a smooth tapered transition from a guidewire tube  436  to the outer tubular member  431 . This transition helps to facilitate the tracking of the outer tubular member  431  over a guidewire  437 . In order to form this smooth transition, the nosepiece  434  may have a length to major diameter ratio ranging from about 3:1 to about 10:1 (the “major diameter” being defined as the largest diameter of the nosepiece). The outer tubular member  431  is not typically permanently secured to the nosepiece  434  and may be retractable from the nosepiece  434  during the deployment sequence. A secondary release cable  438  extends from an opening in the distal section of the elongate shaft. Nosepiece  434  may be grooved to receive secondary release cable  438  if desired.  
       FIG. 24  shows the inner tubular member  430  disposed within the outer tubular member  431  and the guidewire tube  436  disposed within the inner tubular member  430 . The guidewire tube  436  may be made from polymeric materials such as polyimide, polyethylene, polyetheretherketones (PEEK™), or other suitable polymers, and may have an outside diameter ranging from about 0.02 inch to about 0.08 inch, specifically about 0.035 inch to about 0.055 inch. The guidewire tube  436  wall thickness may range from about 0.002 inch to about 0.025 inch, specifically from about 0.004 inch to about 0.010 inch.  
      A release member tube in the form of a release wire tube  441  is disposed about a distal primary release member in the form of a distal primary release wire  442 . The release wire tube  441  is also disposed about a proximal primary release member in the form of a proximal primary release wire  443 . Both the release member tube  441  and an inflation tube  444  are disposed within an inner lumen  445  of the inner tubular member  430 . The outside diameter of the release wire tube  441  may range from about 0.01 inch to about 0.05 inch, specifically about 0.015 inch to about 0.025 inch. The wall thickness of the release wire tube  441  may range from about 0.001 inch to about 0.006 inch, specifically from about 0.002 inch to about 0.004 inch.  
      The outside diameter of the inflation tube  444  may range from about 0.02 inch to about 0.10 inch; specifically from about 0.04 inch to about 0.08 inch. The inflation tube  444  wall thickness may range from about 0.002 inch to about 0.025 inch; specifically from about 0.003 inch to about 0.010 inch.  
      In  FIG. 25 , a potted portion  446  is disposed between an inner surface  447  of a distal end  448  of the inner tubular member  430 , the release wire tube  441 , the guidewire tube  436  and the inflation tube  444 . The potted portion  446  seals the inner lumen  445  of the inner tubular member  430  from bodily fluids that are exposed to the constrained graft  401  and potted portion  446  once the outer tubular member  431  is proximally retracted. The potted portion  446  may be made from adhesives, thermoforming plastics, epoxy, metals, or any other suitable potting material. Alternatively, a molded or machined plug may be bonded or affixed to the distal end of the inner tubular member, with lumens to accommodate the passage of tubes  441 ,  436  and  444 .  
      A more detailed view of the distal section  426  of the elongate shaft  423  is shown in partial section in  FIGS. 26-30 . A distal section  451  of the guidewire tube  436  serves as a primary belt support member  452  and is disposed within the main body portion  402  and ipsilateral leg  404  of the graft  401 . Alternatively, the primary belt support member  452  may be disposed adjacent the graft main body portion  402  and ipsilateral leg  404 . A secondary belt support member housing  453  is secured to the primary belt support member  452 . An additional length of guidewire tube or other elongate member serving as a secondary belt support member  454  is slidably disposed within an appropriately configured lumen  455  of the housing  453 . The secondary belt support member  454  is shown in  FIG. 26  disposed within the graft main body portion  402  and contralateral leg  405 ; however, the secondary belt support member  454  may also be disposed adjacent the contralateral leg  405 , regardless of whether the primary belt support member  452  is disposed adjacent or within the main body portion  402  and ipsilateral leg  404 .  
      The secondary belt support member housing lumen  455  and secondary support member  454  cross sections may be keyed, singly or in combination, to allow relative sliding motion without relative rotation motion and therefore limit any twisting of the secondary support member  454  and the contralateral leg  405 . The secondary belt support member  454  may be made from alloys such as nickel titanium, stainless steel, or polymeric materials such as polyimide and can have an outside transverse dimension ranging from about 0.01 inch to about 0.06 inch.  
      A proximal primary belt  456  is shown in  FIG. 26  disposed about and radially constraining the proximal self-expanding member  407  of the ipsilateral leg  404 . This proximal self-expanding member  407  in turn is disposed about a bushing  457  that is shown as cylindrical in form, but which may have other configurations as well. The bushing  457  is secured to the primary belt support member  452  adjacent the proximal self-expanding member  407  of the ipsilateral leg  404 .  
      A first distal primary belt  458  is disposed about and radially constraining the first distal self-expanding member  422 , which itself is disposed about a cylindrical bushing  461 . A second distal primary belt  462  is disposed about and radially constraining the second distal self-expanding member  411  and the second distal self-expanding member  411  is disposed about a cylindrical bushing  463 .  
      A secondary belt  464  is shown disposed about and radially constraining the proximal self-expanding member  408  of the contralateral leg  405 . This proximal self-expanding member  408  is disposed about a bushing  465  that is cylindrical in shape.  
      As with the other embodiments of the present invention, the belts  456 ,  458 ,  462  and  464  are typically made from nickel titanium, an alloy that is capable of exhibiting a unique combination of high strain without elastic deformation, high strength and biocompatability. However, any other suitable materials may be used including other metallic alloys such as stainless steel, high strength fibers such as carbon, KEVLAR®, polytetrafluoroethylene (PTFE), polyimide, or the like. The outer transverse dimension or diameter of the belts  456 ,  458 ,  462  and  464  can be from about 0.002 inch to about 0.012 inch; specifically about 0.004 inch to about 0.007 inch.  
      A distal portion  466  of the proximal primary release wire  443  is disposed within end loops  468  of the proximal primary belt  456  so as to releasably secure the proximal self-expanding member  407  of the ipsilateral leg  404  in a constrained state. The proximal primary belt  456  may be disposed about the self-expanding member  407  in a hoop-like configuration. The proximal self-expanding member  407  exerts outward radial pressure on the releasably secured belt  456 . The primary proximal release wire  443  is axially moveable within the end loops  468  of the proximal primary belt  456  to allow for release of the belt by proximal retraction of the primary proximal release wire  443  in the same manner as described above with respect to other embodiments of the present invention.  
      Likewise, a distal portion  471  of the distal primary release wire  442  is disposed within end loops  472  of the second distal primary belt  462  that radially constrains the second distal self-expanding member  411 . The second distal primary belt  462  is formed in a hoop configuration about the second distal self-expanding member  411  and the second distal self-expanding member  411  exerts outward radial force on the second distal primary belt  462 . The distal primary release wire  442  is axially moveable within the end loops  472  of the second distal primary belt  462  to allow for release of the radial constraint as discussed above with respect to the proximal primary release wire  443  and as discussed above for other embodiments of the present invention. The distal portion  471  of the distal primary release wire  442  is also disposed within end loops  473  of the first distal primary belt  458  and radially constrains the first distal self-expanding member  422  in a similar fashion.  
      Although the distal primary release wire  442  and proximal primary release wire  443  are shown as two separate components, the release wires  442  and  443  could be combined into a single release member, such as the branched release wire  150  shown in  FIG. 7I  above. A branched release wire is capable of releasing multiple belts in a desired sequence by proper configuration of the lengths of the various branches of the wire. The relative amount of the release wire extending beyond the looped ends of the belt as indicated by reference numeral  156  in  FIG. 7I  controls the timing of the release of the belts. Alternatively, a single release wire may engage both distal and proximal primary belts  456 ,  458  and  462 . As this single release wire  150  is moved proximally, the first distal primary belt  458  is first released, followed by the release of the second distal primary belt  462  and then release of the proximal primary belt  456 .  
      A distal portion  474  of a secondary release member in the form of a secondary release wire  475  is disposed within end loops  476  of a secondary belt  464  that radially constrains the proximal self-expanding member  408  of the contralateral leg  405 . The proximal self-expanding member  408  of the contralateral leg  405  exerts outward radial force on the secondary belt  464  when the self-expanding member  408  is in a constrained configuration. The secondary release wire  475  is axially moveable within the end loops  476  of the secondary belt  464 .  
      A proximal end  477  of the secondary release wire  475  is secured to an actuator hub  478 . A release strand  481  is secured to the actuator hub  478  and is attached to the secondary belt support member  454 , and is shown by way of example in the embodiment of  FIG. 26  as being looped through a hole  482  in the proximal end  483  of the secondary belt support member  454 . Both portions of the release strand  481  that are looped through the proximal end  483  of the secondary belt support member  454  pass into an inner lumen  484  of a release strand tube  485  as seen in  FIG. 27 . The release strand tube  485  passes through an aperture  486  in the distal end  435  of the outer tubular member  431 . Release strand  481  may comprise any filamentary thread or wire, metallic, polymeric, or otherwise, suitable for manipulation as will be herein described. It also may be braided or twisted if desired. The release strand  481  may be made of a filamentary thread of ePTFE.  
      As discussed above with respect to other embodiments, the release wires  442 ,  443  and  475  are generally made from a biocompatible high strength alloy such as stainless steel, but can also be made from any other suitable materials. Examples include other metallic alloys such as nickel titanium, non-metallic fibers such as carbon, polymeric materials, composites thereof, and the like. As discussed above, the diameter and stiffness of the release wires  442 ,  443  and  475  can be important with respect to the diameter and stiffness of the belts  456 ,  458 ,  462  and  464 .  
      The configuration of the end loops  468 ,  472 ,  473  and  476  of the belts  456 ,  458 ,  462  and  464  may vary to suit the particular embodiment of the delivery system  400  and device to be delivered. For example,  FIGS. 7C-7H  illustrate a variety of belt and end loop configurations that may be suitable for delivery systems for bifurcated devices. Referring to  FIG. 7C , belts  112  and  114  are shown having a twisted configuration that has a tendency to reduce snagging or entanglement of the belts  112  and  114  after deployment and release of the belts from a constrained configuration. In addition,  FIG. 7C  illustrates an angle a that belts  112  and  114  make with respect to line  125 . In one embodiment, belts  112  and  114  would be substantially parallel to each other when in an unconstrained state such that this angle is approximately ninety degrees. It may also be desirable to use belts that have end loops that have different cross sectional areas (or transverse dimensions). For example,  FIG. 7E  shows end loops  81 ′ and  81 ″ constrained by release wire  24 . We have found that, depending on the transverse dimension and material of loop  81 ′ disposed within loop  81 ″, elastic deformation of loop  81 ′ can hinder the release process when release wire  24  is proximally retracted. Therefore, it may be desirable to make loop  81 ′ from a material that is substantially smaller in cross sectional area or transverse dimension that that of loop  81 ″. In a particular example, loop  81 ′ is made from nickel titanium wire having a diameter of about 0.003 to about 0.005 inch, and loop  81 ″ is made from the same material having a diameter ranging from about 0.005 to about 0.007 inch.  
      Inflation port  421  extends proximally from the proximal end  416  of the ipsilateral leg  404  of the graft  401 . The inflation port  421  is coupled to a distal end  487  of the inflation tube  444  by a retention mechanism, such as a retention wire  488 , the operation of which can be the same or similar to like embodiments of retention wire  285  discussed above. Typically, the retention wire  488  extends from the inflation port  421  proximally to the proximal adapter  427  of delivery system  400 . The distal end  487  of the inflation tube  444  can be disengaged from the inflation port  421  by pulling on a proximal end  491  of retention wire  488 , as shown in  FIGS. 23, 26  and  31 . The retention wire  488  may be a small diameter wire made from a material such as a polymer, stainless steel, nickel titanium, other alloy or metal, or composite; in a particular embodiment of the invention, retention wire  488  may be a spring formed of a variety of suitable spring materials. Alternatively, the retention wire  488  may have a braided or stranded configuration.  
       FIG. 31  illustrates proximal adapter  427  which is suitable for use with embodiments of the present invention. The proximal adapter  427  houses the proximal termination of the primary release wires  442  and  443 , guidewire tube  436 , retention wire  488  and release wire tube  441 . The proximal adapter  427  has a first side arm  492  with an inner lumen  493  that secures the proximal end  494  of the release wire tube  441  and second side arm  499  having an inner lumen in fluid communication with inflation material lumen  506  that houses proximal end  491  of retention wire  488 . The proximal adapter  427  has a distal primary release wire handle  495  and a proximal primary release wire handle  496  that are disposed in a nested configuration on the first side arm  492 . A proximal end  497  of the proximal primary release wire  443  is secured to the proximal primary release-wire handle  496 . A proximal end  498  of the distal primary release wire  442  is secured to the distal primary release wire handle  495 . This configuration prevents the operator from inadvertently deploying or activating the proximal primary release wire  443  prior to deployment or activation of the distal primary release wire  442  which could result in an undesirable graft  401  deployment sequence.  
      A proximal end  501  of the guidewire tube  436  is secured within a central arm  502  of the proximal adapter  427  that has a potted section  503 . A seal  504  may be disposed on a proximal end  505  of the central arm  502  for sealing around the guidewire lumen and preventing a backflow of fluid. The potted section  503  of the central arm  502  prevents any injected fluids from passing into the inflation material lumen  506  within the proximal adapter  427  or the inner tubular member  430 . The other functions and features of the proximal adapter  427  may be the same or similar to those of the proximal adapters  42  and  323  shown in  FIG. 1  and  FIG. 17  and discussed above.  
       FIG. 32  illustrates a belt support member assembly  507  of the delivery system  400 . The distal end  508  of the secondary belt support member  454  is slidingly disposed within the secondary belt support member housing  453  that is secured to the primary belt support member  452 . The second distal primary belt  462  is secured to the primary belt support member  452  (which in this embodiment is the guidewire tube  436 ) and extends radially therefrom through an optional second distal primary standoff tube  511 . Similar optional first distal primary standoff tube  512 , proximal primary standoff tube  513  and optional secondary standoff tube  514  are disposed on the first distal primary belt  458 , proximal primary belt  456  and secondary belt  464 , respectively.  
      In general, the various features and components (including, e.g., details of various embodiments of the release wires, the self-expanding members, belts, inflation port and tube, guidewire tube, standoff tubes, proximal adapter and its associated components, the materials and dimensions for each of the various components, etc.) as discussed herein with respect to those embodiments of  FIGS. 1-18  may be used in the bifurcated embodiments of the present invention as discussed herein and as illustrated in  FIGS. 19-32 .  
      In use, the delivery system  400  for delivery of a bifurcated intracorporeal device, specifically, a bifurcated graft  401 , can be operated in a similar fashion to the delivery systems discussed above.  FIG. 33  illustrates generally the anatomy of a patient&#39;s heart  515 , aorta  516  and iliac arteries  517 . The aorta extends from the heart  515  and descends into the abdomen of the patient&#39;s body. An aneurysm  518  is disposed in the aorta  516  just below the renal arteries  519 . The aorta  516  branches into the right and left iliac arteries  517  below the aneurysm, which then become the femoral arteries  520 .  
      One delivery procedure of the present invention begins with delivery of a first guidewire  530  into an access hole  531  in a femoral artery, the right femoral artery  532  for the procedure depicted in  FIG. 34 , and advanced distally through the iliac artery  517  and into the patient&#39;s aorta  516 . Access into the femoral artery  532  is generally accomplished with a standard sheath and trocar kit, although sheathless access may also be employed. It should be noted that although the procedure described herein and illustrated in  FIGS. 34-52  is initiated in the right femoral artery  532 , the same procedure could be carried out beginning in the left femoral artery  533  with the orientation reversed. A vasodilator may optionally be administered to the patient at this point as previously discussed. If desired, a vasodilator may also be administered later in the procedure, but preferably prior to or simultaneous with the step of introducing inflation material into the graft  401 .  
      With the first guidewire  530  positioned across the aneurysm  518 , a second guidewire  534  is then introduced into the ipsilateral or right femoral artery  532  and guided into the iliacs  517  and then back down into the contralateral or left femoral artery  533  as shown in  FIG. 35 . A distal end  535  of the second guidewire  534  may then be captured with a snare  536  or similar device inserted through an access hole  537  in the left femoral artery  533 . The distal end  535  of the second guidewire  534  may then be pulled out of the left femoral artery  533  through the same left femoral artery access hole  537 , providing a continuous length of wire passing through each iliac artery  517  via the left and right femoral artery access holes  537  and  531  as shown in  FIG. 35 .  
      Once the second guidewire  534  exits the access hole  537  in the left femoral artery  533 , a tubular catheter  538  may be advanced over the second guidewire  534  through the left femoral artery access hole  537  so as to extend out of the body from the access hole  531  in the right femoral artery  532  as shown in  FIG. 36 . This provides a continuous conduit between the right and left iliac arteries  517 . With a distal end  541  of the tubular catheter  538  extending from the access hole  531  in the right femoral artery  532 , a distal end  542  of the secondary release cable  438  may then be affixed to a proximal end  543  of the second guidewire  534  as shown in  FIG. 37 . For purposes of simplicity, the secondary release cable  438  is shown in, e.g.,  FIGS. 37-40  in schematic form as a single strand. However, it is understood that the term “secondary release cable” encompasses a single or multiple-component feature of the present invention that may be used to assist in the deployment of the graft. For instance, in the embodiment depicted herein, the secondary release cable  438  represents the combination of the release strand  481  and release strand tube  441  discussed above in conjunction with, e.g.,  FIG. 26 . Other variations of this combination are within the scope of the present invention.  
      The second guidewire  534  is then pulled out of the tubular catheter  538  from the left femoral artery access hole  537 , in the direction indicated by the arrow  544  in  FIG. 37 , so that the secondary release cable  438  then extends through the tubular catheter  538  from the right iliac artery to the left iliac artery. The tubular catheter  538  may then be withdrawn, leaving the secondary release cable  438  extending through the left and right iliac arteries  517  from the access hole  531  in the right femoral artery  532  to the access hole  537  in the left femoral artery  533  as shown in  FIG. 38 . The first guidewire  530  remains in position across the aneurysm  518 .  
      The delivery system  400  is then advanced into the patient&#39;s right femoral artery  532  through the access hole  531  over the first guidewire  530  as shown in  FIG. 39 . It may be desirable to apply tension to the secondary release cable  438  as the delivery system  400  is advanced to the vicinity of the aneurysm  518  so as to remove slack in the cable  438  and prevent tangling of the cable  438  or the like. Tension on the secondary release cable  438  may also help to prevent twisting of the delivery system  400  during insertion.  
      FIGS.  37 A-B show an optional marker band that may disposed adjacent nosepiece  434  or generally in the vicinity of the distal end of the delivery system  425 . Such a marker band  551  may also be integral with the delivery system  400 ; for example, it may be incorporated as part of the distal nosepiece  434 . A useful marker  551  can be one that does not add to the profile of the delivery system  400  as shown in  FIG. 37A  (i.e., one that does not give the delivery system  400  a higher diameter). The embodiments of FIGS.  37 A-B are useful in the present embodiment, although they may be used in the embodiments discussed above. Such a marker may be used to aid the operator in introducing the delivery system  400  without twisting.  
      For example, the marker embodiment  551  of  FIG. 37A  comprises a marker body  552  in the form of a simple discontinuous ring made of an appropriate radiopaque material (e.g., platinum, gold, etc.) visible under fluoroscopy, etc. The cross section of the ring may be asymmetric so that under fluoroscopy the cross section may be seen in the vicinity of the discontinuity  553 . The operator will be able to tell if the delivery system  400  is twisted by how the ring  552  is presented under fluoroscopy. Alternatively, ring  552  may be continuous but have a notch or similar cutout to serve the same purpose.  
      The embodiment  554  of  FIG. 37B  is an example of such a marker. Here, both a notch  555  and two circular holes  556  have been cut out of the marker body  557  for easier determination of its orientation when disposed on the notch or other part of the delivery system  400 . For instance, in an orientation where the two circular holes  556  are aligned with respect to the fluoroscope field of view, the user will see a single circular hole to the left of a triangular or vee-shape cutout  555  on the side of the marker  554 . As the angular orientation of the device  400  (and thus the marker  554 ) about the longitudinal axis changes, the appearance of the two circular holes  556  and side notch  555  will change. If the device is twisted clockwise ninety degrees from this orientation along its central longitudinal axis  554 A, for instance, the circles  556  will largely disappear from view and the side notch  555  will generally appear in the front of the field of view as a symmetric diamond. Comparing these views will allow the user to know that the entire delivery system  400  has twisted about ninety degrees. Keeping the same orientation, then, will be made easier with such a marker  554 .  
      For each of the embodiments of FIGS.  37 A-B, variations in the shape, number, orientation, pattern and location of the notch  553  and  555 , holes  556  or other discontinuity, as well as various marker body dimensions cross sectional shape, etc., may be realized, as long as the marker  551  and  554  is configured so that the angular orientation of the delivery system  400  may readily be determined by the user under fluoroscopy or similar imaging technique.  
      The delivery system  400  is positioned in a location suitable for initiating the deployment process, such as one in which the distal end  425  of the delivery system  400  is disposed beyond, or distal to the position in which the graft  401  will be placed, as shown in  FIG. 40 . This position allows the proximal end  483  of the secondary belt support member  454  to be laterally displaced without mechanical interference from the patient&#39;s vasculature. Such clearance for lateral displacement is shown in  FIG. 44 .  
      Once the distal section  426  of the elongate shaft  423  and the endovascular graft  401  are positioned, the deployment process is initiated. First, the outer tubular member  431  is proximally retracted by pulling on the proximal end  433  of the outer tubular member  431  relative to the inner tubular member  430 . The inner tubular member  430  should be maintained in a stable axial position, as the position of the inner tubular member  430  determines the position of the constrained bifurcated graft  401  prior to deployment. Upon retraction of the outer tubular member  431 , the constrained bifurcated graft  401  is exposed and additional slack is created in the secondary release cable  438  as shown in more detail in  FIG. 41 .  
      Alternatively, a variety of different components may be substituted for the outer tubular member  431  in some of the embodiments of the invention. For instance, a shroud, corset, mummy-wrap, or other cover may be released or actuated to expose the constrained graft  401  after the delivering system  400  is introduced into the vasculature.  
      The slack in the secondary release cable  438  is taken up by applying tension to both lengths  561  and  562  of the release strand  481  as shown by the arrows  563  in  FIG. 41 . In alternative embodiments, release strand is not continuous such that lengths  561  and  562  each has a free end, each of which may be manipulated by the operator. As tension continues to be applied to both lengths  561  and  562  of the release strand  481 , the secondary belt support member  454  begins to slide within the secondary belt support member housing  453  in a proximal direction as shown by the arrow  564  in  FIG. 42 . The secondary belt support member  454  continues to slide proximally until all the slack is removed from an axially compressed or folded portion  565  of the contralateral leg  405  of the graft  401  shown in  FIG. 41  and the primary and secondary belt support members  452  and  454  are oriented relative to the secondary belt support member housing  453  as generally shown in  FIG. 43 . Rotational movement of the secondary belt support member  454  relative to the secondary belt support member housing  453  is prevented by the non-circular or asymmetric cross section of the member  454  as shown in  FIGS. 28-28B . This prevents the contralateral leg  405  from twisting or becoming entangled with other components of the graft  401  or delivery system  400  during deployment.  
      Axial compression of all or a portion of the contralateral leg  405  while the graft  401  is in a constrained state within the delivery system  400  prior to deployment allows the axial position of the two proximal self-expanding members  407  and  408  to be axially offset from each other. Alternatively, graft legs  404  and  405  having different lengths may be used to prevent overlap of the self-expanding members  407  and  408  within the delivery system  400 . The cross sectional profile or area of the overlap self-expanding members  407  and  408  is generally greater than that of the adjacent polymer material portion of the legs  404  and  405  of the graft  401 , so eliminating the overlap can be desirable. The self-expanding members  407  and  408  are typically made of a metal or metallic alloy and maintain a cylindrical configuration, even when in a constrained state. The polymer material of the legs  404  and  405  or main body portion  402  of the graft  401 , by contrast, is relatively soft and malleable and can conform to the shape of whatever lumen in which it may be constrained. Placing both proximal self-expanding members  407  and  408  adjacent each other in a compressed state at a single axial position within the delivery system  400  would require a configuration in which two objects having an approximately circular cross section are being placed within another circular lumen. Such a configuration generates a significant amount of wasted or unused cross sectional area within that axial position of the delivery system  400  and would likely result in less flexibility and greater cross section than a delivery system  400  in which the proximal self-expanding members  407  and  408  are axially offset.  
      A gap  566  indicated by the arrows  567  in  FIG. 44  allows the proximal end  483  of the secondary belt support member  454  and secondary release wire actuator hub  478  to move in a lateral direction without mechanical interference from the carina  568  of the iliac artery bifurcation  569 . Gap  566  may vary depending on the patient&#39;s particular anatomy and the specific circumstances of the procedure.  
      The lateral movement of the contralateral leg  405  and secondary belt support member  454  is accomplished by application of tension on both lengths  561  and  562  of the release strand  481  as shown by the arrows  571  in  FIG. 44 . This movement away from the primary belt support member  452  allows the secondary belt support member  454  to transition from alignment with the right iliac artery  572  to alignment with the left iliac artery  573  as shown in  FIG. 44 .  
      Once the ipsilateral leg  404  of the graft  401  and contralateral leg  405  of the graft  401  are aligned with the right and left iliac arteries  572  and  573 , respectively, the delivery system  400  may then be retracted proximally, as shown by the arrow  574  in  FIG. 45 , so as to reposition the distal section  426  of the elongate shaft  423  and the bifurcated graft  401  into the desired position for deployment as shown in  FIG. 45 .  
      As discussed above with respect to placement of a tubular graft  11  embodiment of the present invention, when deploying the graft  401  in the abdominal aorta  516  it is generally desirable to ensure that the distal end  403  of the graft main body portion  402  is installed proximal to, or below, the renal arteries  519  in order to prevent their significant occlusion. However, the distal self-expanding members  411  and  422  of the graft  401  may, depending upon the anatomy of the patient and the location of the aneurysm  518 , partially or completely span the ostia  575  of one or both renal arteries  519 . It can be desirable, however, to ensure that ostia  575  of the renal arteries  519  are not blocked by the distal end  403  of the graft main body portion  402 . As discussed previously, a variety of imaging markers  551  and  554  may be used on either or both the delivery system  400  and the graft  401  itself to help guide the operator during the graft positioning process.  
      After proper positioning, the first and second distal self-expanding members  411  and  422  may then be deployed. The operator first unscrews or otherwise detaches a threaded portion  576  of the distal primary release wire handle  495  from an outer threaded portion  577  of a first side arm end cap  578  shown in  FIG. 31 . Next, the distal primary release wire handle  495  is proximally retracted, which in turn retracts the distal primary release wire  442  in a proximal direction, as shown by the arrow  581  in  FIG. 46 . As the distal end  582  of the distal primary release wire  442  passes through the end loops  472  and  473  of the first distal primary belt  458  and second distal primary belt  462 , the end loops  472  and  473  are released, freeing the first distal self-expanding member  422  and second distal self-expanding member  411  to self-expand in an outward radial direction so to contact an inner surface  583  of the patient&#39;s aorta  516 . The first and second distal primary belts  458  and  462  remain secured to the primary belt support member  452  and will eventually be retracted from the patient with the delivery system  400  after deployment is complete.  
      As the first and second distal self-expanding members  411  and  422  expand and contact the aorta  516 , a distal end  403  of the graft main body portion  402  opens with the self-expanding members  411  and  422  and promotes opening of the graft polymer material portion from the flow of blood into the distal end  403  of the graft main body portion  402  with a “windsock” effect. As a result, once the first and second distal self-expanding members  411  and  422  are expanded to contact the aorta inner surface  583 , the graft main body portion  402  and legs  404  and  405  balloon out or expand while the proximal ends  416  and  417  of the legs  404  and  405  of the graft  401  remain constricted due to the constrained configuration of the proximal self-expanding members  407  and  408  of the ipsilateral and contralateral legs  404  and  405 , as shown in  FIG. 46 . At this point, there typically will be partial or restricted blood flow through and around the graft  401 .  
      Bifurcated graft  401  may then be optionally be inflated with an inflation material via inflation tube  444  and inflation port  421  until the inflatable channels  418  and inflatable cuffs  413 ,  414  and  415  have been filled to a sufficient level to meet sealing and other structural requirements necessary for the bifurcated graft main body portion  402  and the ipsilateral and contralateral legs  404  and  405  to meet clinical performance criteria. As described in later conjunction with an alternative embodiment of the present invention, inflating the graft  401  prior to deploying the proximal and distal self-expanding members  407  and  408 , respectively, is useful in anatomies where the vasculature is tortuous or angled.  
      Next, the proximal self-expanding member  407  of the ipsilateral leg  404  is deployed. Deployment of the first and second distal self-expanding member  411  and  422  has exposed the proximal primary release wire handle  496 , making it accessible to the operator. A threaded portion  584  of the proximal primary release wire handle  496  is unscrewed or otherwise detached from an inner threaded portion  585  of the first side arm end cap  578 . The proximal primary release wire handle  496  may then be retracted proximally so as to deploy the proximal primary belt  456  and proximal self-expanding member  407  of the ipsilateral leg  404  as shown in  FIG. 47 .  
       FIG. 48  depicts an enlarged view of the proximal end  483  of the secondary belt support member  454 . The proximal self-expanding member  408  of the contralateral leg  405  is secured to the proximal end  417  of the contralateral leg  405 . The proximal self-expanding member  408  is constrained in a radial direction by the secondary belt  464 , which has end loops  476  releasably constrained by the distal end  587  of the secondary release wire  475 . The proximal end  477  of the secondary release wire  475  terminates with and is secured to the actuator hub  478 . The release strand is secured to the actuator hub  478  and loops through an aperture or hole  482  in the proximal end  483  of the secondary belt support member  454 . As discussed above, a portion of the release strand  481  is disposed within the release strand tube  485  to form the secondary release cable  438 .  
      When both a first length  561  and second length  562  of the release strand  481  are pulled together in a proximal direction from a proximal end  588  of the secondary release cable  438 , the entire pulling force is exerted on the proximal end  483  of the secondary belt support member  454  because the looped distal end  542  of the release strand  481  pulls on the proximal end  483  of the secondary belt support member  454  without displacing the actuator hub  478 .  
      When deployment of the proximal self-expanding member  408  of the contralateral leg  405  is desired, the operator applies tension in a proximal direction only to the first length  561  of the release strand  481 , which extends proximally from the actuator hub  478 . The direction of such tension is indicated in  FIG. 48  by the arrows  591 . Upon the application of this proximal tension, the actuator hub  478  is moved proximally, as is the secondary release wire  475  that is secured to the actuator hub  478 . The proximal self-expanding member  408  of the contralateral leg  405  deploys when the distal end  587  of the secondary release wire  475  passes through the end loops  468  of the secondary belt  464  so as to release the radial constraint on the proximal self-expanding member  408  imposed by the secondary belt  464 . Upon release of the radial constraint, the proximal self-expanding member  408  expands so as to contact an inside surface  592  of the left iliac artery  573  as shown in  FIG. 49 . Once the proximal self-expanding member  408  of the contralateral leg  405  is expanded, the operator may then apply tension to both lengths  561  and  562  of the release strand  481  to withdraw the secondary belt support member  454  from the housing  453  (as shown in  FIG. 50 ) and remove it from the patient&#39;s vasculature through the left femoral artery access hole  537 .  
       FIG. 51  depicts an alternative embodiment of a belt support member assembly  600  in which the secondary belt support member  601  is detached from the primary belt support member  602  by withdrawal of a latch wire  603 . Generally, all other features of the delivery system  604  of the embodiment of  FIG. 51  can be the same as the delivery systems discussed above. It should be noted, however, that the embodiment shown in  FIG. 51  does not allow the secondary belt support member  601  to slide in an axial direction relative to the primary belt support member  602 . As such, it may be desirable to use this embodiment to deliver and deploy a graft having legs that are not substantially equal in length. Otherwise, if proximal self-expanding members are to be axially offset, the secondary belt support member  601  would have to be detached from the primary belt support member  602  prior to deploying and releasing the secondary belt (not shown).  
      In another configuration (not shown), a similar retention or latch wire  603  passes through aligned aperatures in the secondary belt support member  454  and a housing, such as secondary belt support member housing  453  of  FIG. 43 . Linear and rotational motion of secondary belt support member  454  relative to primary belt support member  452  is prevented until wire  603  is withdrawn, freeing member  454  to be removed from housing  453 . Typically the aperatures are disposed at an angle (such as about 45 degrees) relative to the surface of the members through which they reside so to minimize the angles through which retention wire  603  turn as is passes through the apertures. Retention wire may double as the primary proximal release wire for one or both of proximal self-expanding members  411  and  422 .  
       FIG. 52  shows an alternative belt support member assembly  606  wherein the secondary belt support member  607  is laterally displaced and locked into a position parallel with the primary belt support member  608  prior to removal of the delivery system  609  from the patient&#39;s vasculature. All other features of the delivery system  609  of the embodiment of  FIG. 52  can be the same as the delivery systems discussed above. In use, after all self-expanding members have been deployed, the delivery system  609  is advanced distally into the patient&#39;s vasculature, as shown by the arrow  610  in  FIG. 52 , in order to achieve a gap between a proximal end  611  of the secondary belt support member  607  and the patient&#39;s vasculature as shown by the arrows  612  in  FIG. 52 . A constraining ring  613  is then retracted proximally, as indicated by the arrow  614 , so as to force the secondary belt support member  607  to be laterally displaced as shown by the arrow  615 , also in  FIG. 52 . Once the secondary belt support member  607  has been fully retracted in a lateral direction so as to be substantially parallel to the primary belt support member  608 , the delivery system  609  can then be retracted from the patient&#39;s vasculature.  
      If not previously filled, the bifurcated graft  401  may thereafter be inflated with an inflation material described with respect to the tubular graft embodiment  11 .  
      For all the embodiments described, both tubular and bifurcated, inflation is generally accomplished by inserting or injecting, via one or more device such as a syringe or other suitable mechanism, the inflation material under a pressure- or volume-control environment.  
      For instance, in one embodiment of a pressure-control technique, a volume of inflation material is first injected into the delivery system  400  (which at this point may include the graft, but may also include the inflation tube  444 ). The particular desired volume of inflation material will depend on several factors, including, e.g., the composition and nature of the inflation and polymer graft material, the size of the graft  401  to be deployed, the vessel or lumen diameter into which the graft  401  is deployed, the configuration of the graft  401  (tubular, bifurcated, etc.), the features of the graft main body  402  and (if present) legs  404  and  405 , and the conditions during the procedure (such as temperature).  
      Thereafter, the operator may affix a pressure control device, such as an inflation syringe, to the injection port  621  of the proximal adapter  427  of the inflation tube and apply a pressure to the delivery system  400  and a graft  401  for a period of time. This serves to ensure that the fill material previously introduced enters the graft  401  and fills it to the desired pressure level.  
      We have found that a useful pressure-control approach involves a series of such constant pressure applications, each for a period of time. For instance, the graft  401  may first be pressurized at a level from about 5 psi to about 12 psi or higher, preferably about 9 psi, for between about 5 seconds and 5 minutes, preferably about 3 minutes or more. Optional monitoring of the fluid and the device during the fill procedure may be used to help ensure a proper fill. Such monitoring may be accomplished under fluoroscopy or other technique, for instance, if the fill material is radiopaque.  
      Thereafter, the fill protocol may be completed, or the pressure may be increased to between about 10 psi and about 15 psi or higher, preferably about 12 psi, for an additional period of time ranging from between about 5 seconds and 5 minutes or more, preferably about 1 minute. If the graft  401  so requires, the pressure may be increased one or more additional times in the same fashion to effect the proper fill. For instance, subsequent pressure may be applied between about 12 and 20 psi or more, preferably about 16 psi to 18 psi, for the time required to satisfy the operator that the graft  401  is sufficiently filled.  
      The details of particular pressure-time profiles, as well as whether a single pressure-time application or a series of such applications is used to fill embodiments of the graft  401  will depend on the factors described above with respect to the volume of fill material used; the properties and composition of the fill material tend to be of significance in optimizing the fill protocol. For example, a stepped series of pressure-time profiles as described above is useful when the fill material comprises a hardenable or curable material whose physical properties may be time-dependent and which change after being introduced into the graft  401  and its delivery system  400 .  
      Alternatively, a volume-control method may be utilized to fill embodiments of the grafts  11  and  401 , including both tubular and bifurcated. Here, a volume of fill material is again introduced into the delivery system  400  as described above. In this method, however, the volume of fill material used is precisely enough material to fill the graft  401 , the inflation tube  444 , and any other component in the delivery system  400  through which the fill fluid may travel on its way to the graft  401 . The operator introduces the predetermined quantity of fill material, preferably with a syringe or similar mechanism, into the inflation tube  444  and graft  401 . A precise amount of fill material may be measured into a syringe, for example, so that when the syringe is emptied into the delivery system  400  and graft  401 , the exact desired amount of fill material has reached the graft  401 . After a period of time (which period will depend on the factors previously discussed), the syringe or equivalent may be removed from the inflation tube  444  or injection port  621  of proximal adapter  427  and the procedure completed.  
      A pressurized cartridge of gas or other fluid may be used in lieu of a syringe to introduce the fill material into the delivery system and graft under this volume-control regime so to provide a consistent and reliable force for moving the fill material into the graft  401 . This minimizes the chance that variations in the force and rate of fill material introduction via a syringe-based technique affect the fill protocol and possibly the clinical efficacy of the graft  401  itself.  
      For each of the pressure- and volume-control configurations, an optional pressure relief system may be included so to bleed any air or other fluid existing in the delivery system  400  prior to the introduction of the fill material (such as the inflation tube  444  or graft  401 ) so to avoid introducing such fluid into the patient. Such an optional system may, for example, comprise a pressure relief valve at the graft  401 /inflation tube  444  interface and a pressure relief tube disposed through the delivery system  400  (e.g., adjacent the inflation tube  444 ) terminating at the proximal adapter  427  and vented to the atmosphere.  
      When graft  401  is deployed in certain anatomies, such as those where the iliac arteries are tortuous or otherwise angled, the lumen of one or more of graft inflatable cuffs  413 ,  414  and  415  and channels  418  of may become pinched or restricted in those portions of the graft  401  experiencing a moderate or high-angle bend due to the tortuosity of the vessel into which that portion of graft  401  is deployed. This reduction or even elimination of cuff/channel patency can hinder and sometimes prevent adequate cuff and channel inflation.  
      In addition, graft  401  main body  402  and/or legs  404 ,  405  may, upon initial retraction of outer tubular member  431  and deployment into the vasculature, resist the “windsock” effect that tends to open up the graft to its nominal diameter. Then in turn may lead to inadequate cuff  413 ,  414 , and  415  and channel  418  patency prior to their injection with inflation material. The windsock effect has a higher likelihood of being hindered when graft  401  is deployed in relatively tortuous or angled anatomies; however, it may also be made more difficult when graft  401  (and even tubular graft embodiments such as graft  11 ) is deployed in relatively non-tortuous anatomies.  
      To address this issue, we have found it useful to incorporate an optional ripcord or monofilament into the inflatable channel  418 . Pre-loading such a ripcord  510  into all or a portion of the channel  418  that runs along graft ipsilateral leg  404  and main body portion  402  promotes effective inflation of the graft cuffs and channels as will be described below in detail.  
      Ripcord  510  extends in one embodiment from distal cuff  413  through channel  418 , proximal cuff  414  and inflation port  421 , and continues through inflation tube  444  and through second side arm  499  of proximal adapter  427  as shown in  FIG. 31A . A flexible fill catheter  523  may be affixed to end of second side arm  499  at injection port  509 . Ripcord  510  extends through injection port  509  and catheter  523  where it is affixed to a removable Luer-type fitting or cap  521  at catheter  523  terminus  525  (which can serve as an injection port). Alternatively, in lieu of catheter  523 , fitting  521  may be removably connected directly to injection port  509 . Fill catheter may compromise an optional pressure relief valve (not shown).  
      In use, after graft  401  has been deployed into the vasculature but prior to injecting the inflation material through second side arm  499 , the operator removes fitting  521  from catheter  523  and pulls ripcord  510  proximally out of the ipsilateral graft channel  418 , second side arm  499  and out through the end of catheter  523 . This leaves behind an unobstructed lumen in channel  418  through which inflation material may pass as it is injected into the device, despite any folds, wrinkles, or angles that may exist in graft  401  due to vessel tortuosity or angulation, lack of windsocking, or other phenomena. Inflation material may then be injected into channel  418  and cuffs  413 ,  414  and  415  through second side arm  499  as described elsewhere herein. Inflation material passes through the lumen in channel  418  left behind after ripcord  510  is removed and reaches distal cuff  413 . As cuff  413  fills, a hemostatic seal is created at distal end of graft  401  which promotes the desired windsocking of the graft. This in turn promotes the effective filling of the rest of the cuffs  414 ,  415  and channels  418  and any other lumens in which the inflation material may be directed.  
      Suitable materials for ripcord  510  include polymeric monofilaments, such as PTFE, Polypropylene, nVion, etc. Metallic filaments such as stainless steel, nickel titanium, etc. may be used as well. The diameter of ripcord  510  should be small compared to the diameter of channel  418  lumen to minimize impact on delivery system profile, yet large enough to permit reasonable flow of inflation material into channel  418  lumen following its removal. We have found that a ripcord  510  diameter of between about 0.005 inch and 0.025 inch to be appropriate; in particular, a ripcord diameter of about 0.015 inch is suitable.  
      Alternatively, or in conjunction with ripcord  510 , one or more permanent monofilament lumen patency members or beads may be incorporated into one or more of the cuffs and channels to facilitate the inflation process. We have found it useful to incorporate a single bead into graft contralateral leg  405  channel  418  along with ripcord  510  in the graft ipsilateral leg  404  channel  418 .  
       FIG. 311B  is a simplified cross sectional schematic view of contralateral leg  405  inflatable channel  418  having a bead  520  disposed in a lumen  522  of channel  418 , taken along line  311 B- 311 B in  FIG. 19 . Typically bead  520  extends from proximal cuff  414  to distal cuff  413 , although it may be disposed in only a portion of channel  418  or in other cuffs or channels of graft  401 .  
      Channel  418  is shown in  FIG. 31B  as bent or angled out of the plane of the page to simulate contralateral limb  405  placement in a highly angled iliac artery. Under such bending forces, the walls  524  of channel  418  tend to close on lumen patency member  520 , reducing the size of lumen  522  to be confined to the areas indicated in  FIG. 311B . As can be seen, bead  520  prevents the lumen  522  from collapsing to the point where lumen  522  loses patency sufficient for satisfactory passage of inflation material.  
      Bead  520  may have the same dimensions and comprise materials the same as or similar to ripcord  510 . In particular, we have found a PTFE bead having a diameter of about 0.020 inch to be useful in the channel  418  embodiments of the present invention.  
      We have found that incorporating a ripcord  510  and/or one or more lumen patency members  520  in the system of the present invention enhances the likelihood that graft cuffs and channels will reliably and sufficiently fill with inflation material. In one extreme experiment designed to test the feasibility of this concept, a bifurcated graft contralateral leg  405  having a bead  520  disposed in the contralateral limb channel  418  was tied into a knot at the leg proximal end  417 . Inflation material was injected through ipsilateral leg inflation port  421  under a pressure-control protocol. All cuffs and channels of graft  401 , including contralateral leg channel  418  and proximal cuff  415 , filled completely without having to increase the fill pressure beyond normal levels.  
      Although the benefits of ripcord  510  and one or more beads  520  (together or in combination) may be most readily gained when graft  401  is deployed in tortuous or highly angled anatomies, these components are also useful in grafts deployed in relatively straight and non-tortuous anatomies. They may also be used in tubular stent-grafts of the present invention.  
      Turning now to  FIG. 53 , an embodiment of a bifurcated graft delivery system  625  and method is illustrated. This embodiment is tailored to provide for a controlled withdrawal of a secondary release cable from a lumen of an inner tubular member  628  so to help eliminate the possibility that the release cable  626  becomes entangled or otherwise twisted during deployment.  
      Shown in  FIG. 53  is a well  633  is disposed in the inner tubular member  628 . Well  633  contains a release strand  629  that is looped at its proximal end  634  outside the well  633  through an aperture  635  in the secondary belt support member  636  and that is affixed or attached at its distal end  637  to a second guidewire  638 . The second guidewire  638  is shown in the embodiment of  FIG. 53  as disposed in its own optional lumen  639  within the inner tubular member  628 .  
      Within the well  633 , the release strand  629  is arranged to form a “u-turn” in which it changes direction to double back on itself at juncture  641  as shown in  FIG. 53 . At juncture  641 , a friction line  642  is looped around all or a portion of the release strand  629 . This friction line  642  is fixed to the bottom of the well  633  on one end  642 A and is free on another end  642 B. The friction line  642  is preferably a polymeric monofilament such as polyimide, etc., but may be metallic and may be braided as necessary to achieve the desired friction characteristic needed to interact with release strand  629 . Friction line  642  has a length sufficient to interact with the release strand  629  during the deployment process until the release strand  629  has been completely removed from the well  633  as will now be described in detail.  
      In use, the configuration of  FIG. 53  works as follows. Once the left and right femoral access holes  531  and  537 , discussed above, have been created, the delivery system  625  is introduced into and through the patient&#39;s vasculature. A snare catheter  643  is introduced into the left femoral artery access hole, such as the left femoral artery access hole  537  discussed above. The operator then captures the tip  644  of the second guidewire  638  with the snare  643 . In the embodiment of  FIG. 53 , the second guidewire  638  is shown as pre-attached to the release strand  629  at the distal end  637 .  
      A ball capture tip  638 A or similar member may optionally be disposed on the tip  644  of second guidewire  638  to facilitate its capture by snare catheter  643  and prevent possible injury to the vessel intima. In addition, tip  638 A may be made radiopaque so that it may be readily located by the operator during the procedure. When in the form of a ball, tip  638 A may have a diameter ranging from between about 0.020 inch to about 0.120 inch, specifically, between about 0.040 inch to about 0.060 inch. Although not shown in the figures, second guidewire  638  may also have one or more additional sections branching therefrom, each having a tip or member similar to tip  644 , including tip  638 A, so to provide the operator with one or more alternative sites for capture with snare  643  in case tip  638 A is inaccessible.  
      An angled extension  639 A may optionally be provided on one or both of the top of optional lumen  639  and/or the top of well  633 . Angled extension  639 A may be made of any suitable polymeric or metallic material such as stainless steel. As seen in  FIGS. 53-54 , extension  639 A disposed on the top of lumen  639  is generally biased towards the artery in which snare  643  is disposed at an angle of between about 20 degrees and about 120 degrees, specifically, between about 40 degrees and about 95 degrees, so to guide the release strand  629  and  653  in the proper direction and thus facilitate ease of capture by snare  643 .  
      As the second guidewire  638  is pulled out of the inner tubular member  628  from the left femoral artery access hole  537  in the direction shown by the arrow  544  in  FIG. 37 , the release strand  629  feeds out of the well  633  in an orderly and linear fashion in a direction from the release strand distal end  637  to its proximal end  634 . This is made possible by the forces created at the “u-turn” or juncture  641  by the physical interface with the friction line  642 . The friction force (which can be tailored by the proper combination of release strand  629  and friction line  642  diameters and their materials and by properly dimensioning of the well  633 , for example) provides enough resistance to counter the force applied by the operator so that the “u-turn” or juncture  641  moves in an orderly fashion in a direction from the well bottom  633  to the distal end  646  of the inner tubular member  628  until it exits out of the outer tubular member  628 . At this point, any remaining friction line  642  at the juncture  641  is superfluous as it has served its purpose of facilitating an orderly withdrawal of the release strand  629 . The operator continues to pull on the second guidewire  638  as previously described so that the release strand  629  extends through the left femoral artery access port  537 . We have found the embodiment of  FIG. 53  to be useful in achieving an orderly and tangle-free deployment.  
      Alternatively, any number of other arrangements in which the release strand  629  may be fed out of the outer tubular member  628  in an orderly manner is within the scope of the present invention. For instance, the well  651  shown in  FIGS. 54-56  is, for instance, an extruded polymeric part having a unique cross-sectional configuration that eliminates the need for the friction line  642  in the embodiment shown in  FIG. 53 . Here, a narrowing constraint or gap  652  runs the length of the well interior  651 , forming a physical barrier between first and second opposing portions  654  and  655  of the release strand  653 , shown in  FIGS. 54-56 . The constraint or gap  652  is sized to allow the passage therethrough of the release strand juncture or “u-turn”  656 . As the operator pulls the release strand  653  out of the well  651 , the constraint or gap  652  prevents the opposing portions  654  and  655  of the release strand  653  from crossing into the other side of the well  651 . Said another way, the constraint or gap  652  keeps the juncture or “u-turn”  656  within its vicinity to facilitate an orderly withdrawal of the release strand  653  from the well  651 . In this embodiment, the release strand  653  can have a diameter of between about 0.004 and 0.010 inch; specifically between about 0.006 and 0.007 inch. The gap or constraint  652  should be between about 0.003 and about 0.009 inch; preferably between about 0.005 and about 0.006 inch.  
      Yet another variation of this embodiment, shown in  FIG. 57 , includes a post  661  disposed in a well  652  around which the release strand  663  is wound such that as the operator pulls the distal portion  664  of the release strand  663  out of the distal end  665  of the well  652 , the release strand  663  unwinds in an orderly fashion from the post  661 . The post  661  may be optionally configured to spin on its longitudinal axis, similar to that of a fishing reel spinner, to facilitate the exit of the release strand  663 .  
      Other variations, such as a block and tackle arrangement (not shown), are envisioned in which the release strand  663  is looped through a grommet or similar feature. The grommet provides the necessary friction to prevent the entire release strand  663  from pulling out of the well  652  in one mass as soon as the operator applies a force on a distal end thereof. Any arrangement in which a frictional or similar force is utilized to allow for the orderly dispensation of the release strand  663  from the shaft or post  661  is within the scope of the embodiment contemplated.  
       FIG. 58  depicts an optional hinged design for the belt support members that is particularly useful for deploying the bifurcated stent-graft in tortuous and/or angled anatomies, although it may be used in all anatomies. Bifurcated graft  401  is depicted in phantom for reference. A hinge body  700  is affixed to guide wire tube  436  or primary belt support member  452 . Aperture  702  disposed on one side of primary belt support member  452  is configured to receive hinge attachment member  704 , which in this embodiment is a wire that is looped through aperture  702  and fixed to secondary belt support member  454 . The hinge created at aperture  702  allows support member  454  to swing away from and towards primary belt support member  452  in the direction indicated by arrows  708  in  FIG. 58 .  
      As shown in  FIG. 58 , aperture  702  is disposed on the side of primary belt support member  452  opposite that on which secondary belt support member  454  resides to facilitate extraction of the belt support members from the graft and the patient&#39;s body after graft deployment. However, aperture  702  may also be disposed on the same side of primary belt support member  452  as that of secondary belt support member  454  or in any suitable orientation around member  452 .  
      Release strand  710  is affixed to release strand attachment member  706  at secondary belt support member proximal end  714  and is preferably a stainless steel wire having a diameter of between about 0.004 inch and 0.010 inch, although other materials and diameters may be used. Secondary belt  716  is shown disposed on support member  454  along with optional silicone tubing  711 .  
      Chiefly in tortuous or angled anatomies, but also in straighter vessels, it is useful to allow for a degree of slack in the contralateral limb  405  to be loaded into the elongate shaft  423 . Such slack helps the contralateral leg  405  negotiate various bends in the iliac and/or femoral arteries. The total amount of slack ΔI ideally necessary for a graft limb such as limb  405  to negotiate an angle ΔΘ is represented by the equation: 
 
ΔI=dΔΘ
 
      where “ΔΘ” is the cumulative angle change (the sum of the absolute value of the angles through which the limb must negotiate) along its length, measured in radians, and where “d” is the diameter of the graft limb.  
      The hinge design of  FIG. 58  allows the necessary amount of slack ΔI to be maintained in the contralateral leg  405  both during the step of loading graft  401  in shaft  423  and during graft deployment and placement. Note that in an embodiment of the present invention, a predetermined amount of slack may also be built into the ipsilateral leg  404  as it is assembled for delivery. By building a predetermined amount of slack in each of the legs of graft  401 , the most prevalent patient anatomies may, for instance, be targeted so that the average graft delivery procedure will require the smallest amount of leg adjustment or manipulation by the operator.  
      After graft  401  has been deployed, the apparatus of  FIG. 58  is next withdrawn from the graft and the patient&#39;s vasculature in the direction of arrows  712  as shown in  FIG. 59  over guide wire  530 . During this withdrawal, secondary belt support member  454  rotates about aperture  702  and pivots towards primary belt support member  452  in the direction of arrow  713 . An optional buttress may be employed as described later to facilitate the withdrawal process.  
      Both primary and secondary belt support members are ideally radiopaque to facilitate withdrawal from the vasculature. Secondary belt support member  454  and hinge attachment member  704  should be flexible enough to turn the corner around graft bifurcation  406  with little or no permanent deformation as the operator withdraws the primary belt support member  452  in the direction of arrows  712 .  
      Withdrawal of member  452  causes secondary belt support member  454  to first retreat from contralateral limb  405  until the proximal end  714  of secondary belt support member  454  clears the graft walls in the vicinity of bifurcation  406 , allowing the hinge to further act to align secondary belt support member in a generally parallel relationship with primary belt support member  452  as both are then withdrawn through the ipsilateral leg  404  and eventually out of the patient&#39;s body through right femoral access hole  531 . Release strand  710  follows secondary belt support member  454  out of the body.  
      FIGS.  59 A-B depict a variation of this hinge design that limits rotation of the secondary belt support member  454  to a single plane. Here, hinge body  732  is fixedly disposed on a distal portion  451  of primary belt support member  452  and comprises an offset flanged pin  734  or like element. Pin  734  is disposed in an aperture  736  that runs through the distal end  508  of secondary belt support member  454  and hinge body  732 . In this configuration, secondary belt support member  454  is rotatably secured to pin  734  by optional flange  738  and is free to rotate about pin  734  in the direction indicated by arrows  740  to facilitate withdrawal of the delivery apparatus from the patient. The optional offset feature of pin  734  assists in the extraction of the belt support members from the graft and the Patient&#39;s body after graft deployment.  
       FIG. 60  shows a close up partial cross-sectional view of the proximal end  417  of graft contralateral leg  405  disposed on the  FIGS. 58-59  (or alternatively FIGS.  59 A-B) secondary belt support member  454 . Release strand tube  718 , part of secondary release cable  721 , houses release strand  710 , a secondary release wire  719  (which holds secondary belt  716  around contralateral proximal self expanding member  408 ), and a shield line  720  that is fixedly attached at its distal end  722  to optional contralateral self-expanding member shield  724 .  
      Optional expanding member shield  724  comprises PET or similar polymeric material. Shield  724  acts as a shroud to cover proximal self-expanding member  408 , protecting ipsilateral leg  404  from being damaged by self-expanding member  408  during delivery system assembly and graft deployment. Further, shield  724  prevents direct contact between contralateral self-expanding member  408  and ipsilateral self-expanding member  407 , keeping the various self expanding member components from snaring one another or otherwise getting entangled. The exact position of graft contralateral proximal self-expanding member  408  relative to graft ipsilateral leg  404  and self-expanding member  407  will depend on several factors, one of which is the degree of slack built into the graft legs  404 ,  405  on members  452  and  454 .  
      Shield  724  may be removed prior to retraction of secondary release wire  719  by retracting shield line  720  in the direction indicated by arrow  729 , typically after release strand tube  718  has been removed, and ultimately out of the patient&#39;s body through left femoral artery access hole  537 . As shield  724  is retracted, release strand  710  and secondary release wire  719  pass through wire apertures  728  and  730 , respectively. Alternatively, a single wire aperture may be disposed on shield  724  through which both release strand  710  and secondary release wire  719  pass.  
      A variation in the deployment sequence that may be used with any of the sequences and equipment described above may be appropriate in certain clinical settings when the patient&#39;s vasculature exhibits a degree of tortuosity and/or angulation.  
      Related to the cuff and channel lumen patency matter discussed above are at least two additional considerations when deploying a device such as bifurcated graft  401  in tortuous or angled anatomies. First, it can be more challenging to maintain the patency of either or both the blood flow passageways formed by the walls of graft contralateral leg  405  and/or ipsilateral leg  404 . Such challenges may also be presented in the blood flow passageways defined by graft main body  402  of the bifurcated graft  401  and tubular graft  11  embodiments. This may in turn negatively affect the patency of the cuff and channel lumens such that the cuffs and channels cannot adequately be filled with inflation material. Second, the outer tubular member  431  can be more difficult to retract proximally relative to inner tubular member  430  when the delivery system  400  is disposed in such angled and/or tortuous anatomies.  
      The delivery method discussed with respect to  FIGS. 34-50  teaches that the steps of deploying the distal and proximal self-expanding members are accomplished prior to the step of inflating the graft cuffs and channels. A variation in this deployment sequence that is useful for tortuous or angled patient anatomies is discussed below in conjunction with the delivery system components of  FIGS. 31A, 31B  and  58 - 60 , although any of the delivery systems or their components described herein may employ this sequence variation.  
      During the delivery procedure, after the first and second distal self expanding members  411  and  412  have been released, the operator removes release strand tube  718  from the body through the left femoral access hole  537 . This exposes release strand  710 , secondary release wire  719 , and shield line  720 .  
      Next, the shield line  720  is pulled in a proximal direction  729  by the operator to remove shield  724  from the contralateral leg proximal end  417 , exposing self-expanding member  408 . A buttress, which can be a tubular member such as a catheter or the like, is threaded on the remaining secondary release wire  719  and release strand  710  and advanced distally until it physically abuts the proximal end  483  of the secondary belt support member  454 . This provides a relatively stiff column that the operator may use to move the graft contralateral leq  405  in a distal direction as well as react the force necessary to deploy self-expanding member  408  by retracting release wire  719 .  
      The operator next detaches Luer-type fitting or cap  521  from flexible fill catheter  523  and removes ripcord  510  from channel  418 . Graft  401  cuffs and channels may then be filled with inflation material as previously described. When the inflation material is radiopaque or otherwise observable in vivo, the operator may interrogate the shape of the graft  401  and the various cuffs and channels under fluoroscopy or other suitable imaging technique to determine qraft limb patency, the sufficiency of graft cuff and channel inflation, and whether any folds or other irregularities in the graft exist so that they may be corrected. When observed under fluoroscopy, the operator may adjust the C-arm of the fluoroscope to interrogate graft  401  from a number of angles.  
      If necessary, and after cuff and channel inflation but before proximal self-expanding member deployment, the operator may manipulate both the buttress catheter and/or release strand  710  to push or pull, respectively, the qraft contralateral leq into. the proper position. By making fine adjustments in either direction, the operator may remove or add slack in the graft contralateral leg  405  and ensure optimal qraft placement and patency. To minimize operator confusion, the release strand  710  and stent release wire  719  may be different lenqths, color coded, flagged or otherwise labeled, etc. We have found that making the stent release wire  719  shorter than release strand  710  helps in maintaining optimal operator orientation with respect to the various components of the qraft delivery system.  
      When the operator is satisfied with the position, patency, and appearance of graft  401 , contralateral self-expanding member  408  may be deployed by applying tension in the proximal direction  729  on secondary release wire  719  so that secondary belt  716  releases proximal self-expanding member  408  in the manner previously described.  
      Similarly, the operator next may adjust the position of the ipsilateral leg  404  of graft  401  by adjusting the position of primary belt support member  452  and then release proximal self-expanding member  407  of the ipsilateral leg  404  as described herein.  
      To withdraw the delivery apparatus, guide wire  530  is partially withdrawn in the proximal direction through nosepiece  434  into guide wire tube  436  to a point proximal of cuff  413 . This prevents the guide wire  530  from possible interference with proper inflation of cuff  413 . Next, the distal end  487  of the inflation tube  444  may be disengaged from the inflation port  421  by pulling on a proximal end  491  of retention wire  488  as previously discussed. Using the buttress to push on belt support member proximal portion  483  if necessary, the operator may then proximally withdraw the primary belt support member  452  over guide wire  530  with the secondary belt support member  454  following. Finally, guide wire  530  is removed through left and right femoral access holes  537 ,  531 , which may then be repaired using conventional techniques.  
      It is clear to those of skill in the art that although particular techniques and steps are described herein that we have found to be useful, variations in the order and techniques in which the various deployment steps described herein are within the scope of the present invention.  
      While particular forms of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be so limited.