Abstract:
An endoluminal prosthesis is provided with an improved fixation system for coupling the endoluminal prosthesis to an inner wall of a lumen and to reduce distal migration. According to an embodiment of the present invention, a laterally protruding member atraumatically engages the ostium of a side or branch vessel. The protruding member may be fixed to a portion of a prosthesis. In one embodiment the protruding member is provided on a modular fixation device for initial fixation within the body lumen with the finger member within the side or branch vessel. A primary endoluminal prosthesis is then fixed to the modular fixation device to bypass a diseased portion of the anatomy.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to tubular prostheses such as grafts and endoluminal prostheses including, for example, stent-grafts and aneurysm exclusion devices, and methods for placement of such grafts and endoluminal structures. In particular, the present invention relates to a system for intraostial endoluminal prosthesis fixation.  
         BACKGROUND OF THE INVENTION  
         [0002]    A wide range of medical treatments have been previously developed using “endoluminal prostheses,” which terms are herein intended to mean medical devices which are adapted for temporary or permanent implantation within a body lumen, including both naturally occurring or artificially made lumens. Examples of lumens in which endoluminal prostheses may be implanted include, without limitation: arteries such as those located within coronary, mesentery, peripheral, or cerebral vasculature; veins; gastrointestinal tract; biliary tract; urethra; trachea; hepatic shunts; and fallopian tubes. Various types of endoluminal prostheses have also been developed, each providing a uniquely beneficial structure to modify the mechanics of the targeted luminal wall.  
           [0003]    A number of vascular devices have been developed for replacing, supplementing or excluding portions of blood vessels. These vascular grafts may include but are not limited to endoluminal vascular prostheses and stent grafts, for example, aneurysm exclusion devices such as abdominal aortic aneurysm (“AAA”) devices that are used to exclude aneurysms and provide a prosthetic lumen for the flow of blood. Typically these endoluminal prostheses or stent grafts are constructed of graft materials such as woven polymer materials (e.g., Dacron,) or polytetrafluoroethylene (“PTFE”) and a support structure. The stent-grafts typically have graft material such as a woven polymer, secured onto the inner diameter or outer diameter of a support structure that supports the graft material and/or holds it in place against a luminal wall.  
           [0004]    One very significant use for endoluminal or vascular prostheses is in treating aneurysms. Vascular aneurysms are the result of abnormal dilation of a blood vessel, usually resulting from disease or a genetic predisposition, which can weaken the arterial wall and allow it to expand. While aneurysms can occur in any blood vessel, most occur in the aorta and peripheral arteries, with the majority of aneurysms occurring in the abdominal aorta. Typically an abdominal aneurysm will begin below the renal arteries and may extend into one or both of the iliac arteries.  
           [0005]    Aneurysms, especially abdominal aortic aneurysms, have been treated in open surgery procedures where the diseased vessel segment is bypassed and repaired with an artificial vascular graft. While considered to be an effective surgical technique in view of the alternative of a fatal ruptured abdominal aortic aneurysm, the open surgical technique suffers from a number of disadvantages. The surgical procedure is complex and requires long hospital stays due to serious complications and long recovery times and has high mortality rates. In order to reduce the mortality rates, complications and duration of hospital stays, less invasive devices and techniques have been developed. The improved devices include tubular prostheses that provide a lumen or lumens for blood flow while excluding blood flow to the aneurysm site. They are introduced into the blood vessel using a catheter in a less or minimally invasive technique. Although frequently referred to as stent-grafts, these devices differ from covered stents in that they are not used to mechanically prop open natural blood vessels. Rather, they are used to secure an artificial lumen in a sealing engagement with the vessel wall without further opening the natural blood vessel that is already abnormally dilated.  
           [0006]    Most currently used AAA devices comprise a main body portion fixed at the infrarenal aorta junction. The prostheses are typically secured to a vessel wall above and below the aneurysm site with at least one attached expandable annular spring member that provides sufficient radial force so that the prosthesis engages the inner lumen wall of the body lumen to seal the prosthetic lumen from the aneurysm. The devices are typically delivered by initially placing a main body endoluminally and engaging the device to the aorta wall by a series of self-expanding annular spring members. The main body is frequently a bifurcated device with a long and short iliac leg for directing blood flow through the iliac arteries. A contralateral leg is delivered and coupled to the short leg of the bifurcated main body graft. Iliac and/or aortic cuffs then may be delivered if desired to improve or extend deployment or fixation through desired regions.  
           [0007]    In general, in many diseased vessels, the area for prosthesis fixation above an aneurysm or other diseased portion may be limited, making secure fixation of the prosthesis more difficult. In addition, over time there is a possibility that the prosthesis may migrate. A number of devices or solutions have been proposed to improve fixation super renal fixation has been provided to improve fixation. However, particularly in a diseased patient, there may be suprarenal cholesterol or atheroma plaques that may dislodge, fragment or release from the supra renal area. In other devices, other mechanisms have also been used to engage the vessel walls such as, for example, hook like members that puncture the vessel wall. The hooks traumatize the tissue and therefore may be undesirable. Increased radial force has been proposed to improve fixation as well. However, in some patients, migration may occur when the neck or region in which the graft is deployed expands or otherwise changes over time and thus increased radial force may not prevent migration in such a situation.  
           [0008]    It would accordingly be desirable to provide a stent graft fixation system that provides improved fixation with a confined or limited area upstream of an aneurysm site. It would also be desirable to provide a device that reduces migration of the stent graft. It would also be desirable to provide an improved fixation system for an endoluminal prosthesis that reduces trauma to tissue.  
         SUMMARY OF THE INVENTION  
         [0009]    An embodiment according to present invention provides an endoluminal prosthesis with an improved fixation system for deploying the endoluminal prosthesis within a body lumen and reducing distal migration of the prosthesis. The fixation system comprises at least one laterally extending member or finger member extending from a portion of a prosthesis, where the finger member is to be deployed within a proximal branch lumen. The finger member may be incorporated into the main prosthesis or may be included with a modular portion of the prosthesis such as a short cuff that is initially deployed within the body lumen, with the longer main prosthesis subsequently fixed to the cuff. The finger member is configured to be non-piercing or relatively atraumatic to tissue. The finger member may be a self-expanding so that it tends to open or extend laterally when not constrained. In one embodiment, the finger member extends laterally at about 90 degrees from the prosthesis.  
           [0010]    In one embodiment a modular fixation device or cuff is provided with at least one intraostial finger member. The cuff is configured for initial fixation to a lumen wall. A longer endoluminal prosthesis is provided and is coupled to the cuff to bypass a diseased portion of the anatomy. The cuff may provide a more reliable landing zone for the prosthesis and a more predictable, consistent engagement area, while the finger further prevents distal migration of the cuff. In one embodiment, the cuff comprises one or more support structures and a graft material surrounding at least a portion of a support structure. The cuff is arranged to engage the inner lumen wall at a fixation site and form a leak resistant seal with the inner wall of the body lumen. The finger member when deployed extends laterally from the sidewall of the tubular member and into the branch vessel.  
           [0011]    The cuff and finger member initially secure the proximal fixation area. Then, when an adequate seal and fixation is made available through the cuff and finger member, the main body of the prosthesis is delivered inside the cuff and deployed in a manner that provides fixation and seal between the prosthesis and the cuff. An example of such cuff and prosthesis is described in U.S. Application entitled “ENDOVASCULAR STENT GRAFT AND FIXATION CUFF” filed on Apr. 25, 2002 and incorporated herein by reference.  
           [0012]    In one embodiment, the prosthesis is constructed of a tubular graft material (such as a woven polymer for conducting fluid) supported by annular spring members. According to one variation, the finger member is coupled to the cuff and is constructed of loop of a spring like material such as a Nickel Titanium alloy having superelastic properties. The finger member may also be coated by a material such as a polymer film to protect adjacent tissue. The finger member has one portion coupled to the prosthesis (for example, by welding onto the annular spring member) and a free end that is free from the prosthesis. The spring finger member tends towards a lateral position with respect to the sidewall of the prosthesis. Prior to deployment, the finger member is confined or restrained into a position substantially parallel to the prosthesis sidewall. When initially, partially deployed, the finger member is released and positioned above or at an ostium of a branch vessel. The prosthesis, partially deployed and partially retained by a deliver catheter, is drawn distally with the catheter and the free end of the finger member is positioned over the ostium, it springs towards an open position and catches the ostium. The prosthesis is drawn distally until the finger member is located within the branch vessel and then is fully released from the catheter  
           [0013]    When deployed, the annular members of the prosthesis expand to maintain the prosthesis in a conformed, sealing arrangement with the inner wall of the body lumen. The finger member is positioned so that the free end is within the ostium of a side branch vessel as described above. If the prosthesis is a fixation cuff, an endoluminal prosthesis is then deployed within the cuff. The annular members of the prosthesis support the tubular graft and maintain the lumen provided by the prosthesis, open and in a conformed, sealing arrangement with the inner wall of the cuff, providing a lumen through which body fluids may flow.  
           [0014]    The annular support members each comprise an annular expandable member formed by a series of connected compressible diamond structures. The finger member is preferably coupled to the proximal most annular support member and may be integrally formed therewith so that it extends about 1 or 2 millimeters above the renal ostium, which is not to be blocked by the prosthesis. Alternatively, for example, the expandable member may be formed of an undulating or sinusoidal-like patterned wire ring or other compressible spring member. Preferably the annular support members are radially compressible springs biased in a radially outward direction, which when released, bias the prosthesis into conforming fixed engagement with an interior surface of the vessel. Annular support members are used to create a seal between the prosthesis and the inner wall of a body lumen, as well as to support the tubular graft structures. The annular springs are preferably constructed of Nitinol. Examples of such annular support structures are described, for example, in U.S. Pat. Nos. 5,713,917 and 5,824,041 incorporated herein by reference. When used in an aneurysm exclusion device, the springs have sufficient radial spring force and flexibility to conformingly engage the body lumen inner wall to avoid excessive leakage, and prevent pressurization of the aneurysm, i.e., to provide a leak resistant seal. Although some leakage of blood or other body fluid may occur into the aneurysm isolated by the prosthesis, an optimal seal will reduce the chances of aneurysm pressurization and the possible resulting rupture. The annular support members are attached or mechanically coupled to the graft material along the tubular graft by various means, such as, for example, by stitching onto either the inside or outside of the tubular graft.  
           [0015]    An aneurysm exclusion device according to the invention may be used in other regions such as the thoracic region.  
           [0016]    The endoluminal prosthesis may be in the form of either a straight single-limb tubular member or a generally Y-shaped bifurcated tubular member having a trunk joining at a graft junction with a pair of lateral limbs, namely an ipsilateral limb and a contralateral limb. In an abdominal aneurysm, a bifurcated device is frequently preferred. In such a bifurcated prosthesis, the proximal portion of the prosthesis comprises a trunk with a proximal opening, and a distal portion branched into at least two branches with distal openings. Thus, body fluids may flow from the proximal opening through the distal openings of the branches. Preferably the ipsilateral limb is longer so that when deployed, it extends into the common iliac. A single limb extension member is provided having a mating portion for coupling with a lateral limb of a bifurcated member and an adjustable length portion extending coaxially from a distal end of the mating portion.  
           [0017]    The compressed profile of the prosthesis with the finger member is sufficiently low to allow the prosthesis to be placed into the vasculature using a low profile delivery catheter. The prosthesis can be placed within a diseased vessel via deployment means at the location of an aneurysm. Various means for delivery of a prosthesis through the vasculature to the site for deployment, are well known in the art and may be found for example is U.S. Pat. Nos. 5,713,917 and 5,824,041. In general, the prosthesis is radially compressed and loaded in or on the distal end of the catheter for delivery to the deployment site. The aneurysm site is located using an imaging technique such as fluoroscopy, and the catheter is guided through a femoral iliac artery with the use of a guide wire to the aneurysm site.  
           [0018]    A guide wire may be initially inserted through the femoral artery to the aorta and into the renal artery where the finger of the prosthesis is to be deployed. This may assist in locating the distal end of the sheath at the ostium of the renal artery where the finger member of the prosthesis is to be deployed Once appropriately located, a sheath on the catheter covering or restraining the prosthesis is retracted to release the finger member. Once the finger member is appropriately located in the ostium, the sheath may be further retracted releasing the prosthesis, allowing the annular springs to expand and attach or engage the prosthesis to the inner wall of the body lumen. Alternatively, the prosthesis may be positioned and released with the finger member slightly above the ostium. The finger member expands when released and may be constrained to some extent by the inner wall of the lumen. The free end of the finger member is located at the ostium of a branch vessel by drawing the prosthesis distally until the finger member is located in the ostium. Once the finger member is in position, the prosthesis may be fully deployed and released from the catheter. A marker may be placed on the prosthesis so that the circumferential orientation of the finger member may be determined for positioning it at the ostium of the side or branch vessel.  
           [0019]    These and further aspects of the invention are exemplified and in the detailed description of embodiments according to the invention described below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1A is a side view of a cuff according to an embodiment according to the invention initially deployed in an aorta, proximal of its intended final deployment position.  
         [0021]    [0021]FIG. 1B is an enlarged perspective view of a portion of the cuff and anatomy of FIG. 1A.  
         [0022]    [0022]FIG. 2 is a perspective view of a portion of the cuff of FIG. 1A with the free end of the finger located at the ostium of a renal artery.  
         [0023]    [0023]FIG. 3 is a perspective view of the cuff of FIG. 1A as the cuff is further moved distally to a fully deployed position in the aorta.  
         [0024]    [0024]FIG. 4A is a side view of another embodiment according to the invention with the cuff covered by a sheath in place for deployment in an aorta.  
         [0025]    [0025]FIG. 4B is a side view of the cuff of FIG. 4A as the sheath is initially retracted.  
         [0026]    [0026]FIG. 4C is a side view of the cuff of FIG. 4A as the sheath is further retracted and the finger is located in the ostium.  
         [0027]    [0027]FIG. 5A is a partial cross section of another embodiment according to the invention with the cuff covered by a sheath in place for deployment in an aorta.  
         [0028]    [0028]FIG. 5B is a partial cross section of the cuff of FIG. 5A as the sheath is initially retracted.  
         [0029]    [0029]FIG. 5C is a partial cross section of the cuff of FIG. 5A as the sheath is further retracted and the finger is located in the ostium.  
         [0030]    [0030]FIG. 6 is a side view with a partial cross section of an another embodiment of a prosthesis according to the invention.  
         [0031]    [0031]FIG. 7 is a side view with a partial cross section of an another embodiment of a prosthesis according to the invention.  
         [0032]    [0032]FIG. 8 is a side view and partial cross section of a long prosthesis in place in the cuff of FIGS.  1 A- 3  located in an aorta. 
     
    
     DETAILED DESCRIPTION  
       [0033]    FIGS.  1 A- 8  illustrate various embodiments of a cuff with a finger member or extension, and endoluminal prosthesis, a delivery system and a method according to the present invention. Although a fixation cuff, endoluminal prosthesis, delivery system and method according to the invention may be used in any body lumen that conducts body fluid and may be used as a single lumen prosthesis or a multibranch prosthesis, they are described herein with reference to treatment of an aortic aneurysm, in particular in the abdomen of a patient using a bifurcated prosthesis.  
         [0034]    FIGS.  1 A- 3  and  7  illustrate a an embodiment of a fixation cuff according to the present invention. The cuff  110  comprises a tubular graft layer  115 , a series of radially compressible annular support members  112  attached to the tubular graft layer  115 , and a finger member  116  extending laterally of the proximal most support member  112   a . The finger member  116  is welded to the proximal most support member  112   a  and is configured to extend 1 or 2 millimeters above the cuff  110  when in its deployed position. The annular support members  112  are attached to the tubular graft member  115  using sutures or other coupling means. The cuff  110  is generally between about 5 and 20 mm in length so that when the finger is located in a renal artery, it may be placed from the aorta renal junction and extend towards the aortic aneurysm  18 . The cuff  110  provides an inner circumferential area to which the prosthesis  210  (FIGS. 6 and 7) may be secured.  
         [0035]    The finger member  116  is preferably a spring loop made of a Nitinol wire and having a thin layer or film about the wire loop to provide a relatively atraumatic member and to protect adjacent tissue. The finger member  116  has a first portion comprised of members  117   a ,  117   b  attached to the distal portion of the support member  112   a , and coupled by spring loops  118   a ,  118   b  to a free end  119 , free from the cuff  110 . The finger member  116  is shape set to a position extending laterally from the centerline of the cuff  110 . The spring loops  118   a ,  118   b  provide flexibility to the finger member  116  and also permit variations in length of the finger member  116 . The finger member  116 , when loaded in a catheter or otherwise restrained, is compressed into a position that is substantially parallel to the sidewall  115   a  of the tubular graft  115 . In this position, the free end  119  extends towards the distal portion  110   d  of the cuff  110 . When released, the free end  119  tends to spring towards a position extending laterally of the sidewall  115   a  of the tubular graft  115 .  
         [0036]    The annular support members  112  are preferably spring members having predetermined radii and are preferably constructed of a material such as Nitinol in a superelastic, straight annealed condition. The support members  112  comprise a series of connected diamond structures  111  around the circumference of the annular member  112  that form peaks  113  and valleys  114 . Other annular support structures may be used as well, such as a sinusoidal or undulating wire spring member. In FIGS.  1 A- 3 , the annular support members  112  are in an expanded position. Prior to deployment the annular members  112  are compressed. The annular members  112  are configured to support the cuff and  110  and/or bias the cuff  110  into conforming fixed engagement with the inner wall of the aorta  10 .  
         [0037]    The tubular graft  115  is preferably formed of a biocompatible material with a textured inner surface such as velour so that it better engages the outer circumference of a prosthesis fixed to the cuff  110  and provides a better seal. Alternatively or in addition, an outer tubular graft may also be provided and may be formed of a textured surface such as velour to better engage the inner wall of the aorta  10  and provide a better seal. The velour also is a low porosity woven fabric to provide a leak resistant seal. The graft material is relatively thin-walled so that it may be compressed into a small diameter, yet capable of acting as a strong, leak-resistant, fluid conduit when in tubular form.  
         [0038]    Referring to FIGS.  1 A- 3 , the cuff  110  is illustrated located in an aorta  10  after being deployed by a catheter. The aorta  10  is joined by renal arteries  12  and  14  at the aorto-renal junction  16 . In the ostia  22 ,  24  (the portion of the renal arteries  12 ,  14  respectively where the aorta  10  joins the arteries  12 ,  14 ) the arteries  12 ,  14  are slightly enlarged. Just below the aorta-renal junction  16  is an aneurysm  18 , a diseased region where the vessel wall is weakened and expanded. Below the aneurysm  18 , the aorta  10  bifurcates into right and left iliac vessels  11 ,  13 , respectively. The finger member  116  is to be located, for example, within one of the renal arteries  12 ,  14 . The renal arteries  12 ,  14  typically are not directly across from each other, one being located distal of the other. The finger member  116  is preferably to be placed in the distal-most renal artery  14  so that the cuff  110  does not block either of the renal arteries  12 ,  14 . The selection of the renal artery into which the finger  116  is deployed may occur prior to surgery using imaging to determine which renal artery would be appropriate for this purpose.  
         [0039]    Referring to FIG. 1A, the prosthesis, in the embodiment a cuff  110 , is delivered into the abdominal aorta  10  using a catheter  105  including a sheath  106  used to retrain the cuff  110  until deployed. In FIG. 1A, the cuff  110  is partially deployed within an aorta  10  above the aneurysm  18  by partially retracting the sheath  106 . The proximal most portion  110   a  of the cuff  110  is located above the renal artery  14 , which in this instance is the distal most of the renal arteries  12 ,  14 . The finger  116  is located above the renal artery  14 , which defines an ostium  24  at its junction with the aorta  10 . The free end  119  of the finger member  116  is just proximal of the ostium  24 .  
         [0040]    Referring to FIG. 2, the cuff  110  is drawn in a proximal direction until the free end  119  is at the opening into the ostium  24  where it catches the ostium  24   
         [0041]    In FIG. 3, the finger member  116  is located within the renal artery  14  where the finger member  116  extends in a direction substantially laterally and radially of the sidewall  115   a  of the cuff  110 . The finger member  116  will engage the ostium  24  of the renal artery  14  thus preventing distal migration of the cuff  110  (as the force to re-bend the finger to release it from the ostium will be generally higher than needed to prevent the cuff&#39;s release and migration—the finger acts as a stop to limit the possibility of migration).  
         [0042]    Between the aorta-renal junction  16  and the aneurysm  18  is a region of the aorta  10  where the cuff  110  is engaged with the inner wall of the aorta  10 . Annular support members  112  are designed to exert a radially outward force sufficient to bias the cuff  110  into conforming fixed engagement with the inner wall of the aorta above aneurysm  18  to support the tubular graft  115  and to provide a leak resistant seal between the cuff  110  and the inner wall of the aorta  10 . The cuff  110  may be slightly longer or shorter than the area between the aorta-renal junction  16  and the aneurysm  18 , which varies from patient to patient. As such the cuff  110  provides more predictable area for deploying the endoluminal prosthesis.  
         [0043]    To deploy the cuff  110 , it may be loaded into a catheter in a collapsed small diameter configuration. Annular members  112  are held in a radially compressed position by a sheath or cover placed over the cuff  110  to facilitate its delivery. The cuff  110  is delivered in a collapsed constrained configuration via the catheter through a surgically accessed femoral artery, to the desired deployment site below the aorta-renal junction  16 . The sheath of the catheter positioned over the cuff  110  is retracted when the distal end of the catheter is located at the deployment site within the cuff  110  releasing the annular members  112  from the compressed position to an expanded position engaging the inner wall of the aorta  10 . The cuff  110  is positioned as described herein with respect to FIGS.  1 A- 3 .  
         [0044]    [0044]FIG. 8 illustrates an endoluminal prosthesis  210  after it has been deployed within the cuff  110  of FIGS.  1 A- 3 . A similar prosthesis may be deployed in the cuffs  120 ,  140  and  190  of FIGS.  4 A- 4 C,  5 A- 5 C and  6  respectively.  
         [0045]    In FIG. 8, the prosthesis  210  comprises a tubular graft  215  and a series of radially compressible annular support members  212  attached to tubular graft  215 . In FIG. 6, the annular support members  212  are in an expanded position. Prior to deployment the annular members  212  are compressed. The annular members  212  support the graft and/or bias the prosthesis  210  into conforming fixed engagement with an interior surface of the cuff  110 . The annular support members  212  are preferably spring members having predetermined radii and are preferably constructed of a material such as Nitinol in a superelastic, straight annealed condition.  
         [0046]    The tubular graft  215  is preferably formed of a biocompatible, low-porosity woven fabric, such as a woven polyester. The graft material is thin-walled so that it may be compressed into a small diameter, yet capable of acting as a strong, leak-resistant, fluid conduit when in tubular form. In this embodiment, the annular support members  212  are sewn on to the outside of the tubular graft  215  material by sutures. Alternative mechanisms of attachment may be used and the annular support members  212  may be attached to the inside of the tubular graft  215 . The support members  212  comprise a series of connected diamond structures  211  around the circumference of the annular member  212  that form peaks  213  and valleys  214 .  
         [0047]    The prosthesis  210  includes a main body portion  216  and a contralateral iliac extension limb  220 . The main body portion  216  is a tubular bifurcated member having has an aortic portion  217 , a long ipsilateral iliac limb portion  218 , and a short iliac portion  219 . The diamond structures  211  a around the circumference of the proximal most annular member  212   a  form peaks  213   a  and valleys  214   a  where the valleys  214   a  form protrusions (not shown) extending in a circumferential direction from the tubular graft  215 . When deployed, the prosthesis  210  may be maneuvered so that the protrusions (not shown) engage the graft material or threads of the graft material of the tubular member  115  of the cuff  110   
         [0048]    As illustrated in FIG. 8. The proximal end  222  of the prosthesis  210  is placed within the cuff  110 , which is placed within the aorta-renal junction  16  in the abdominal aorta  10  as described herein with reference to FIGS.  1 A- 3 . Annular support members  212  are designed to exert a radially outward force sufficient to bias the tubular graft  215  of the endoluminal prosthesis  210  into conforming fixed engagement with the interior surface of the cuff  110  to support the tubular graft  215 , and/or to provide a leak resistant seal between the prosthesis  210  and the cuff  110  which provides a seal between itself and the inner wall of the aorta  10 . The proximal aortic portion  222  of the prosthesis  210  is located within cuff  110 , and the long ipsilateral iliac portion limb  218  is located within the right iliac vessel  11 . After deployment of the main body portion  216 , the contralateral iliac extension limb  220  is located within left iliac vessel  13 , and near the graft junction  221  within the short iliac portion  219 . The proximal end  220   a  of the contralateral iliac extension limb  220  includes a proximal support member (not shown) biasing the proximal end  220   a  into conforming fixed engagement with the interior surface the short iliac portion  219 .  
         [0049]    To deploy the prosthesis  210 , the main body portion  216  of the prosthesis may be loaded into a catheter a collapsed configuration where a sheath or cover placed over the prosthesis  210  holds the annular members  212  in a radially compressed position. The main body portion  216  is delivered in a compressed configuration via the catheter through a surgically accessed femoral artery, to the desired deployment site. The sheath  10  placed over the prosthesis  210  is retracted when the distal end of the catheter is located at the deployment site within the cuff  110 . The annular members  212  are then released from the compressed position to an expanded position. The proximal annular members  212  engage the inner wall of the cuff  110  while the remaining portion extends distally through the aorta  10  beyond the aneurysm  18  with the long ipsilateral limb portion  218  extending into the right iliac vessel  11 . Protrusions  223  from the annular support member  212   a  of the prosthesis  210  may engage the material of the inner tubular graft  115  of the cuff  110  as the prosthesis  210  is pulled distally through the cuff  110  to position the prosthesis to provide additional fixation.  
         [0050]    FIGS.  4 A- 4 C illustrate another embodiment of a cuff according to the invention. The cuff  120  comprises a tubular graft layer  125 , a series of radially compressible annular support members  122  attached to the tubular graft layer  125 , and a finger member  126  tending to extend laterally of the proximal most support member  122   a . The finger member  126  is welded to the proximal most support member  122   a  and is configured to extend 1 or 2 millimeters above the cuff  120  when in its deployed position. The cuff  120  is constructed in a similar manner as the cuff  110  described above with reference to FIGS.  1 A- 3  and is used with a prosthesis in a manner similar to the use of the cuff  110  with prosthesis  210  described herein with reference to FIG. 8.  
         [0051]    The finger member  126  is preferably a spring wire made of a having a first portion  127  attached to the distal portion of the support member  122   a , an elbow  128  where the finger member bends, and a free end  129 , free from the cuff  120 . The finger member  126  is illustrated in FIG. 4A in a position in which it is constrained by a sheath  121  of a catheter into which the cuff  120  is loaded. In this position the free end  129  extends in a direction proximal of the proximal end  120   a  of the cuff  120 .  
         [0052]    As illustrated in FIG. 4A, a guidewire  130  is inserted within the aorta, along the side of the sheath  121 , and into the renal artery  14 . The guidewire  130  which can be seen by fluoroscopy, provides a mechanism for locating the renal artery when deploying the finger  126  into the renal artery  14 . The cuff  120  is located so that the finger is adjacent the renal artery  14 . Various imaging techniques may be used to orient the catheter sheath  121  including various radiopaque markers (not shown) on the cuff  120  and/or sheath  121 .  
         [0053]    Referring to FIG. 4B, the sheath  121  is retracted and the finger member  126  tends to rotate towards a lateral position illustrated in FIG. 4B until the free end  129  is at the opening into the ostium  24  of the renal artery  14 . At this time the catheter may be repositioned so that the finger  126  is more precisely located at the ostium  24 . (The length of the finger in a pivoting configuration is no longer than the diameter of the branch vessel into which the finger is to be pivoted into place, and is usually somewhat shorter than the diameter of the branch vessel (otherwise pivoting of the finger may be prevented)).  
         [0054]    Referring to FIG. 4C, the sheath  121  is then further retracted to deploy the cuff  120 . The support members  122  expand to engage the inner wall of the aorta  10  at the aorta-renal junction  16  while the finger member  126  is located within the renal artery  14  where the finger member  126  extends slightly above the cuff  120  with the free end  129  extending in a direction laterally (radially of the cuff  120 ) of the elbow  128  of the finger member  126  to engage the ostium  24 .  
         [0055]    FIGS.  5 A- 5 C illustrate another embodiment of a cuff according to the invention. The cuff  140  comprises a tubular graft layer  145 , a series of radially compressible annular support members  142  attached to the tubular graft layer  145 , and a finger member  146  tending to extend laterally of the proximal most support member  142   a . The finger member  146  is welded to the proximal most support member  142   a  and is configured to extend 1 or 2 millimeters above the cuff  140  when in its deployed position. The cuff  140  is constructed in a similar manner as the cuff  110  described above with reference to FIGS.  1 A- 3  and is used with a prosthesis in a manner similar to the use of the cuff  110  with prosthesis  210  described herein with reference to FIG. 8.  
         [0056]    The finger member  146  is preferably spring loop made of a Nitinol wire and having a thin layer or film about the wire loop to protect adjacent tissue. The thin layer or film may be a macroporous material such as a textile or a microporous material such as a polymer film, e.g., PTFE. The textile or fiber may be wrapped around, bonded or sutured onto the loop. The finger member  146  has a first portion  147  with members  147   a ,  147   b  attached to the distal portion of the support member  142   a , and coupled by spring loops  148   a ,  148   b  to a free end  149 , free from the cuff  140 . The finger member  146  is shape set to a position extending laterally of the cuff  140 . The spring loops  148   a ,  148   b  provide flexibility to the finger member  146  and also permit variations in length of the finger member  146 . The finger member  146 , when loaded in a catheter or otherwise restrained, is compressed into a position that is substantially parallel to the sidewall  145   a  of the tubular graft  145 . The finger member  146  is illustrated in FIG. 5A in a position in which it is constrained by a sheath  141  of a catheter into which the cuff  140  is loaded. In this position, the free end  149  extends proximally of the proximal end  140  of the cuff  140 . When released, the free end  149  tends to spring towards a position extending laterally of the sidewall  145   a  of the tubular graft  145 .  
         [0057]    As illustrated in FIG. 5A, a guidewire  150  is inserted within the aorta  10 , along the side of the sheath  141 , and into the renal artery  14 . The guidewire  150  provides a mechanism for locating the renal artery when deploying the finger  146  into the renal artery  14 . The cuff  140  is located so that the finger  146  is adjacent the renal artery  14 . Various imaging techniques may be used to orient the catheter sheath  141  including various radiopaque markers (not shown) on the cuff  140  and/or sheath  141 .  
         [0058]    Referring to FIG. 5B, the sheath  141  is retracted and the finger member  146  tends to spring towards a lateral position illustrated in FIG. 5B until the free end  149  is at the opening into the ostium  24  of the renal artery  14 . At this time the catheter may be repositioned so that the finger  146  is more precisely located at the ostium  24 .  
         [0059]    Referring to FIG. 5C, the sheath  141  is then further retracted to deploy the cuff  140 . The support members  142  expand to engage the inner wall of the aorta  10  at the aorta-renal junction  16  while the finger member  146  is located within the renal artery  14  where the finger member  146  extends slightly above the cuff  140  with the free end  149  extending in a direction laterally or radially of the sidewall  145   a  of the tubular graft  145  into the ostium  24 .  
         [0060]    [0060]FIG. 6 illustrates another embodiment of a cuff. The cuff  190  comprises a tubular graft layer  195 , a series of radially compressible annular support members  192  attached to the tubular graft layer  195 , and a finger member  196  extending laterally of the proximal most support member  192   a . The annular support members  192  and tubular graft member  195  are constructed and attached in a similar manner as the annular support members  112  and graft  115  of cuff  110  described above with reference to FIGS.  1 A- 3 . The cuff  190  may be secured with the prosthesis  210  in a similar manner as the cuff  110  and prostheses  210  are fixed as described below.  
         [0061]    The finger member  196  is preferably a wire made of a shape memory alloy having a first portion  198  attached to the cuff  190  and a free end  199 , free from the cuff  190 . The finger member is constructed of a Nickel-Titanium alloy and is welded to one or more of diamond structures  191  that form the proximal support member  192   a . The wire member is preferably coated with a biocompatible material that provides a thrombo-resistant or non-thrombogenic surface, such as silicone, polyethylene, polypropylene or other polymer. The finger member  196 , when loaded in a catheter or otherwise restrained, is compressed into a position that is substantially parallel to the sidewall  195   a  of the tubular graft  195 . In this position, the free end  199  extends towards the distal portion  190   d  of the cuff  190 . When released, the free end  199  tends to spring towards a position extending laterally of the sidewall  195   a  of the tubular graft  195 . The cuff  190  and finger member  196  are positioned in a similar manner as cuff  110  and finger member  116  as described with reference to FIGS.  1 A- 3 . The cuff  190  is used with a prosthesis in a manner similar to the use of the cuff  110  with prosthesis  210  described herein with reference to FIG. 8.  
         [0062]    [0062]FIG. 7 illustrates an alternative embodiment of the invention in which a prosthesis  310  constructed in a similar manner as prosthesis  210  (FIG. 8) includes a finger member  316  for engaging an ostium of a renal artery to prevent distal migration of the prosthesis  310 . The prosthesis  310  comprises a tubular graft  315  and a series of radially compressible annular support members  312  attached to tubular graft  315 . In this embodiment, the annular support members  312  are sewn on to the outside of the tubular graft  315  material by sutures. The support members  312  comprise a series of connected diamond structures  311  around the circumference of the annular member  312  that form peaks  313  and valleys  314 . The prosthesis  310  includes a main body portion  316  and a contralateral iliac extension limb  320 . The main body portion  316  is a tubular bifurcated member having has an aortic portion  317 , a long ipsilateral iliac limb portion  318 , and a short iliac portion  319 . When the prosthesis  310  is fully deployed, the contralateral extensions  320  extends from the short iliac portion  319  of the main body  316 .  
         [0063]    The finger member  316  is constructed in a similar manner as finger member  116  (FIGS.  1 A- 3  and  8 ) and is welded to a proximal most support structure  312   a . The finger member  316  and the prosthesis  310  are deployed in a similar manner as the finger member  116  and cuff  110  described herein except that the prosthesis  310  is deployed to completely bypass the aneurysm.  
         [0064]    In the embodiments described herein, the prosthesis may include radiopaque markers that are positioned in a manner in which rotational alignment may be determined prior to deploying the finger member. Such markers are generally know to one of skill in the art.  
         [0065]    While the invention has been described with reference to particular embodiments, it will be understood to one skilled in the art that variations and modifications may be made in form and detail without departing from the spirit and scope of the invention.