Abstract:
Methods for accessing the common and internal iliac arteries and delivering and deploying an endovascular graft therein utilizing an ipsilateral approach are disclosed. A system including a pre-loaded delivery and deployment device to enable such a method to be practiced is also disclosed.

Description:
BACKGROUND 
     This invention relates generally to medical devices and methods of using the same, and more particularly, to an endovascular stent graft and methods for placement and deployment of the graft in the lumen of a branched vessel. 
     Stent grafts may be inserted into an anatomical vessel or duct for various purposes. For example, stent grafts are used for treatment of vasculature in the human or animal body to bypass a repair or defect in the vasculature or to maintain or restore patency in a formerly blocked or constricted passageway, such as following a balloon angioplasty procedure. For example, a stent graft may extend proximally and/or distally away from a vascular defect, including a diseased portion of an aneurysm, and engage a healthy portion of a vessel wall. In many cases, however, such a damaged or defective portion of the vasculature may include a branch or side vessel such as an internal iliac artery extending from the common iliac artery. Thus, it has been proposed to provide a stent graft having a side branch which, when deployed, is positioned over the opening to the internal iliac artery and then, if desired, another stent graft can be deployed through the side branch into the internal iliac artery to bypass a diseased portion thereof and restore the blood flow path to the internal iliac artery. 
     Generally, when deploying an endovascular stent graft into a vessel lumen, it is possible to obtain access to such a lumen from one or both ends of the vessel where necessary, thereby facilitating placement of a graft in the desired portion of the lumen. However, the internal iliac artery, which extends from the common iliac artery below the aortic bifurcation, is a blind vessel because there is no practical way of performing a minimally invasive endovascular procedure into that vessel other than by entry from the common iliac artery. 
     Access to and introduction of a stent graft into the common and/or internal iliac arteries and successful deployment of a stent graft in such vessels may often depend upon a favorable layout of the arteries and, in many cases, access is difficult. One known approach that has been used includes accessing the target location(s) within the vessels by a contralateral or crossover approach. In other words, a guide wire and/or sheath may be first introduced into a common iliac artery and then snared or pulled from the contralateral side so that the wire and/or sheath extends across the aortic bifurcation where it can be positioned proximal to the opening of the internal iliac artery in which treatment or repair is desired. In this way, a pathway is created to facilitate the introduction and deployment of a stent graft to the target location in the contralateral internal iliac artery. 
     As endovascular techniques become more refined, physicians continue to seek novel alternative approaches to treating diseased vessels, including blind vessels that are difficult to access and traverse. For example, accessing the target location(s) within the internal iliac artery using an ipsilateral approach (as opposed to the contralateral approach) and therefore avoiding the above-described “crossover” manipulation of a guide wire or sheath over the aortic bifurcation is desirable. Accordingly, a method for accessing the internal iliac arteries utilizing an ipsilateral approach and a pre-loaded deployment system to enable such a method to be practiced is described herein. 
     While this invention will be generally discussed in relation to a stent graft and method of deployment thereof into a common iliac artery where it is necessary to extend a side branch from a main portion or body of the graft into an internal iliac artery, it is also contemplated that the invention is not so limited and may relate to any body or vessel lumen in which such a deployment is necessary or desired. 
     SUMMARY 
     The present disclosure provides a system and method for delivering and deploying an endovascular graft into one or more branched vessels using an ipsilateral approach. 
     In one example, the system comprises a delivery device comprising a pusher catheter having a proximal end portion and a distal end portion and a first, second and third lumen extending at least partially between the proximal and distal end portions. An auxiliary sheath having a proximal end portion and a distal end portion extends longitudinally within the first lumen of the pusher catheter and a guide wire cannula having a proximal end portion and a distal end portion extends longitudinally within the second lumen of the pusher catheter. 
     The system further preferably comprises a stent graft carried on the delivery device. In one example, the stent graft has a main tubular body of a biocompatible graft material having a proximal end and a distal end defining a main lumen therebetween. A side branch extends from the main tubular body and has a lumen extending therethrough and in fluid communication with the main lumen. Preferably, the stent graft is configured to be deployed into the vasculature of a patient with the main tubular body being located in the common iliac artery and the side branch being directed towards an internal iliac artery of the common iliac artery. An auxiliary guide wire extends proximally within the lumen of the auxiliary sheath and into the distal end of the main tubular body of the stent graft, and further extends distally through at least a portion of the lumen of the side branch and through the third lumen of the pusher catheter. 
     The system may also preferably include a second delivery device. In one example, the second delivery device comprises a second guide wire cannula having a proximal end portion and a distal end portion and a lumen extending therebetween. A second stent graft is carried on the proximal end portion of the second delivery device. The second stent graft has a tubular body of a biocompatible graft material defining a main lumen and is configured to be deployed into the internal iliac artery. A second sheath is mounted coaxially over and radially outside at least a portion of the second stent graft. 
     A method for treating a diseased vessel is also described. In one example, the method comprises the steps of introducing a first delivery device into a patient&#39;s vasculature, such as a common iliac artery. The delivery device preferably comprises a pusher catheter having a proximal end portion and a distal end portion and at least two lumens extending therebetween; an auxiliary sheath having a proximal end portion and a distal end portion extending longitudinally within one of the at least two lumens of the pusher catheter and a first prosthesis carried on the first delivery device. The first prosthesis has a main tubular body of a biocompatible graft material having a proximal end portion and a distal end portion defining a main lumen therebetween, and a side branch extending from the main tubular body. The side branch has a lumen extending therethrough and is in fluid communication with the main lumen. Preferably, the first prosthesis is configured to be deployed into the vasculature of a patient with the main tubular body being located in the common iliac artery and the side branch being directed towards an internal iliac artery of the common iliac artery. An auxiliary guide wire extends longitudinally in a proximal direction within the lumen of the auxiliary sheath and into the distal end of the main tubular body of the stent graft, the auxiliary guide wire further extending through at least a portion of the lumen of the side branch and extending longitudinally in a distal direction through the other of the at least two lumens of the pusher catheter. 
     The method also preferably comprises at least partially deploying the first prosthesis in the common iliac artery; introducing a second delivery device ipsilaterally though the lumen of the main tubular body of the first prosthesis and the lumen of the side branch of the first prosthesis, the second delivery device carrying a second prosthesis thereon, the second prosthesis comprising a tubular body defining a lumen; positioning the second prosthesis within the internal iliac artery; and at least partially deploying the second prosthesis in the internal iliac artery. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side view of one example of a pre-loaded delivery and deployment system with a stent graft mounted thereon. 
         FIG. 2  is a perspective view of one example of the proximal end portion of a pre-loaded delivery device with a stent graft mounted thereon. 
         FIG. 3  is a perspective view of the pre-loaded delivery device shown in  FIG. 2  with a further delivery device carrying a leg extension stent graft extending through the side branch lumen and positioned for insertion into an internal iliac artery. 
         FIG. 4  is a perspective view of another example of the proximal end portion of a pre-loaded delivery device with a stent graft mounted thereon. 
         FIG. 5  is a perspective view of the pre-loaded delivery device shown in  FIG. 4  with a further delivery device carrying a leg extension stent graft extending through the side branch lumen and positioned for insertion into an internal iliac artery. 
         FIGS. 6-11  show an example of the various stages of the introduction, placement and deployment of a stent graft into a common iliac artery and an internal iliac artery using an ipsilateral approach. 
         FIG. 12  is a perspective view of one example of proximal retention of a stent graft to a delivery device. 
         FIG. 13  is a cross-sectional view of the arrangement shown in  FIG. 12 . 
         FIG. 14  is a perspective view of one example of distal retention of a stent graft to a delivery device. 
         FIG. 15  is a perspective view of another example of distal retention of a stent graft to a delivery device. 
     
    
    
     DETAILED DESCRIPTION 
     Throughout this specification the terms “proximal” and “proximally” are used for a position or direction towards the patient&#39;s heart and the terms “distal” and “distally” are used for a position or direction away the patient&#39;s heart. The term “ipsilateral” is used to indicate that the diseased vessel(s) being accessed during a given procedure are on the same side of the body (right or left) as the vascular access device/introducer, while “contralateral” signifies that the vessel(s) of interest are on the opposite side of the body. 
     The embodiments described below are in connection with systems and methods for the introduction and deployment of an implantable medical device in a vessel, such as endovascular prosthesis, but could also be used for deploying a range of implantable medical devices including, but not limited to, stents, stent grafts, occlusion devices and the like. 
     Referring to  FIG. 1 , an example of a stent graft delivery device, also referred to herein as an “introducer”, is shown generally at  2  with a stent graft  4  mounted onto it. During the medical procedure to position and deploy the stent graft, the proximal end  6  of the device  2  will travel through the vessel lumen to a desired deployment site. The distal external manipulation section  8  which may include a handle portion, which is acted upon by a user to manipulate the device, remains outside of the patient throughout the procedure. The delivery device  2  is preferably “pre-loaded”, or in other words, before the delivery device is introduced into the patient&#39;s vasculature, it is pre-assembled with mechanisms that facilitate graft delivery and deployment already arranged thereon. The delivery and deployment mechanisms may include, for example, one or more guide wires, catheters, sheaths, stent grafts and combinations thereof, which are arranged on and/or are carried by the device  2 . 
     In one non-limiting example, the pre-loaded device  2  preferably includes a mechanism, such as one or more catheters, sheaths and/or guide wires, which extend from a distal external manipulation portion  8  to a proximal end portion  6  where the stent graft  4  is carried. The pre-loaded guide wire(s), catheter(s) and/or sheath(s) remain in place during delivery of the stent graft  4  into a patient&#39;s vasculature and aid in placement and deployment of one or more additional or side branch extension stent grafts in a desired location in accordance with the systems and methods described herein. 
     More specifically, as shown in  FIG. 1 , the device  2  includes a pusher catheter  10  having a proximal end portion  12  and a distal end portion  14 . In one example, the pusher catheter  10  has at least one, but preferably, more than one lumen extending between the proximal  12  and distal  14  end portions. For example, the pusher catheter  10  may have three separate lumens extending longitudinally at least partially between the proximal and distal end portions  12 ,  14  of the pusher catheter. A sleeve or sheath  16 , which may be operated by a sheath manipulator  18 , is preferably mounted co-axially over the pusher catheter  10 . In the ready-to-deploy position, the sheath  16  extends proximally to the nose cone dilator  20  and covers a stent graft  4  carried on the device  2 . As illustrated in  FIG. 1 , however, the sheath  16  is withdrawn so that the stent graft  4  is exposed to show detail of the assembly. A handle  22  at the distal end  14  of the pusher catheter  10  enables manipulation of various components of the device  2 . 
     As shown in  FIG. 1 , a guide wire cannula  24  extends through one of the lumens of the pusher catheter  10 , from the distal end  8  of the device to immediately distal of the nose cone dilator  20 . A branched stent graft  4  may be retained on the device  2 , and, in one example, the proximal end of the graft  3  may be secured to the guide wire cannula  24 , by a retention arrangement (see  FIGS. 12 and 13  for one example of a proximal retention arrangement) immediately distal of the nose cone dilator  20 . The branched stent graft  4  may also be retained at its distal end  5  by another retention arrangement (see  FIGS. 14 and 15  for examples of a distal retention arrangement) on the device  2 . 
     As shown in  FIGS. 2 and 4 , an auxiliary sheath  26  preferably extends through another of the multiple (e.g. three) lumens of the pusher catheter  10  and exits from the pusher catheter  10  (in the pre-deployment state) so that the proximal end or tip  28  of the auxiliary sheath  26  is adjacent the distal end  5  of the branched stent graft  4 . The stent graft  4  carried on the device  2  preferably has a substantially tubular main body  30  having a proximal end portion  3  and a distal end portion  5  with a main lumen  32  extending through the main tubular body  30 . A side branch  34 , also preferably having a substantially tubular body defining a lumen  36 , preferably extends from the main body  30  and may be integrally formed with the main body, or alternatively, the side branch  34  may be a separately formed component that is secured to the main body  30  such as by stitching, bonding, adhesive or the like. In either case, the side branch  34  is preferably formed with and/or secured to the main body  30  adjacent a fenestration  38  or opening in the main body  30  so as provide fluid communication between the lumen  32  of the main body and the lumen  36  of the side branch. In one example, both the main body  30  and the side branch  34  are preferably comprised of one or more biocompatible materials including, but not limited to, polyesters, fluorinated polymers and polyurethanes and/or may be made from natural or organic materials. The materials may also be subjected to surface modifications or coatings. 
     In a preferred example, the stent graft  4  is configured to be deployed into the vasculature of a patient with the main tubular body  30  being located in the common iliac artery and the side branch being directed towards an internal iliac artery of the common iliac artery, although other stent graft configurations for deployment into various other body vessels are also contemplated depending on various factors including, but not limited to the particular vessel(s) being treated and/or the location of a particular damaged or diseased portion of a vessel. 
     Turning to  FIGS. 2-5 , within the auxiliary sheath  26  there is an auxiliary guide wire  40  extending therethrough. This auxiliary guide wire  40  extends beyond the proximal tip  28  of the auxiliary sheath  26  and through the lumen  32  of the graft main body  30  and at least partially through the lumen  36  of the side branch  34 . For example, a pre-loaded delivery device which has particular application in the delivery and deployment of a stent graft into the internal iliac artery is shown in exemplary  FIGS. 2-5 . In a first “pre-deployment” position, the auxiliary guide wire  40  extends proximally beyond the distal tip  28  of the auxiliary sheath  26 . The auxiliary guide wire  40  enters the main lumen  32  of the stent graft  4  through the graft distal end  5 . The auxiliary guide wire  40  then bends in a “U-turn” fashion over the graft bifurcation  42  to enter the side branch  34 . The auxiliary guide wire  40  thus enters the lumen  36  of the side branch through a proximal end portion  44  of the branch  34 , and hence, it passes through a portion of the main lumen  32  of the stent graft  4  before it bends and enters the lumen  36  of the side branch  34 . 
     In one example of the pre-loaded delivery device  2  as shown in  FIGS. 2 and 3 , the auxiliary guide wire  40  extends through the entire longitudinal length of the side branch lumen  36  before exiting the branch at distal end  46  and continuing distally along the outside of the main body  30  of the stent graft  4 . The auxiliary wire  40  then re-enters a separate or third lumen of pusher catheter  10  (the first and second lumens of the pusher catheter having the auxiliary sheath  26  and the guide wire cannula  24 , respectively, extending longitudinally therethough as described above), and the auxiliary guide wire  40  runs distally through the third lumen, back towards the distal end  8  of the device  2 . 
     An alternative example of a pre-loaded delivery device is illustrated in  FIGS. 4 and 5 . The same reference numerals are used for corresponding features to those of  FIGS. 2 and 3 . Like  FIG. 2 , the auxiliary wire  40  enters the main lumen  32  of the stent graft  4  through the graft distal end  5 . The auxiliary wire  40  then extends partially into the proximal end portion  44  of the side branch lumen  36  and then pierces through the graft material near the proximal end portion  44  of the side branch  34 . The auxiliary wire  40  then continues in a generally distal direction along the outside of the side branch  34  and main graft body  30 , where it preferably re-enters the third lumen of pusher catheter  10  and extends back towards the distal end of the device  8 . 
     Thus,  FIGS. 2 through 5  and show several non-limiting examples of a device  2  with a stent graft  4  carried thereon that has been “pre-loaded” with a delivery and deployment mechanism that includes the auxiliary guide wire  40  running through the auxiliary sheath  26  and pusher catheter  10 , respectively, through the stent graft lumen  32  and back though a separate lumen of the pusher catheter  10  to the distal end of the device  8 . 
     As illustrated in  FIGS. 3 and 5 , the auxiliary sheath  26  may be advanced over the auxiliary wire  40  through the main lumen  32  of the graft and at least partially advanced into the proximal end portion  44  of the side branch lumen  36 . More specifically, in one example, the auxiliary sheath  26  may be advanced from the first “pre-deployment” position described above and shown in  FIG. 2  (in which the proximal end portion  28  of the sheath  26  is located distally of the distal end  5  of the graft) to a second position shown in  FIG. 3  in which the sheath  26  has been advanced proximally over the auxiliary wire  40  though the main body lumen  32  and then generally distally though the side branch lumen  36 , such that the tip  28  of the auxiliary sheath  26  has exited the distal end  46  of the side branch lumen  36 . As such, if the main graft body  30  were located in the lumen of a common iliac artery in the arrangement shown in  FIG. 3 , the auxiliary sheath  26  would preferably be positioned or directed towards an internal iliac artery of the common iliac artery. 
     In another alternative example, as illustrated in  FIG. 5 , the auxiliary sheath  26  can also be advanced over the auxiliary wire  40  though the main body lumen  32 . However, the sheath  26  can only be tracked over the wire  40  and extend partially into the proximal end portion  44  of the side branch lumen  36 , until the tip  28  of the sheath abuts the interior surface of the side branch lumen  36  adjacent to the point where the auxiliary guide wire  40  pierces though the wall and exits the side branch lumen  36 . 
     Now looking at  FIGS. 6 through 11 , it will be seen that there is schematically illustrated a series of vessels within the human body, including the common iliac arteries  48  and  50  and the respective internal iliac arteries  52  and  54 . The systems and methods described herein find particular application in the delivery, placement and deployment of one or more stent grafts therein, although as discussed earlier, the disclosed systems and methods are not restricted to this particular purpose and may be used in a variety of applications as will be appreciated by one of skill in the art. 
     Turning to  FIG. 6 , a descending aorta  56  extends down to an aortic bifurcation  58  from which extend common iliac arteries  48  and  50 . From each of the common iliac arteries an internal iliac artery  52  and  54 , respectively, extends. In most cases, the internal iliac arteries  52  and  54  cannot be practically accessed from their distal ends remote from the junction with the common iliac artery. For illustrative purposes, internal iliac artery  52  is shown as having a diseased portion, including an aneurysm  60  in  FIGS. 6 through 11 , although, it will be appreciated that one or both common iliac arteries  48 ,  50  and/or one or both internal iliac arteries  52 ,  54  may also include diseased portions that may be treated in accordance with the systems and methods described herein. 
     As shown in  FIG. 6 , a guide wire  62  has been extended into a femoral artery via a femoral incision (not shown) and extended proximally beyond the aortic bifurcation  58  to the descending aorta  56 . The device  2  has then been introduced into the common iliac artery  48  over the guide wire  56  with the nose cone dilator  20  extending nearly up to the aortic bifurcation  58 . Preferably, the delivery device  2  as described herein carries a stent graft  4  thereon that has been “pre-loaded” with a delivery and deployment mechanism. At this stage, a sheath  16 , extending proximally up to the nose cone dilator  20  covers the branched stent graft  4  that is carried on the device  2 , so that the stent graft  4  is not visible in  FIG. 6 . With the device  2  in this position within the lumen of common iliac artery  48 , the stent graft  4  (enclosed within the sheath  16 ) is preferably adjacent to the opening of the internal iliac artery  52 . 
     As shown in  FIG. 7 , the sheath  16  has been withdrawn (in a distal direction) to expose the branched stent graft  4  so that the sheath  16  is just distal of the proximal end portions  12 ,  28  of pusher catheter  10  and the auxiliary sheath  26 , respectively. At this stage the branched stent graft  4  is partially unconstrained in that it has been freed from the confines of the sheath  16 , but it is still retained by a retention mechanism at one or both of the proximal  3  and distal  5  ends of the stent graft. Accordingly, the stent graft  4  is not yet in a fully expanded condition within the lumen of the common iliac artery  48 . It can be seen that the stent graft  4  carried on the device  2  is pre-loaded in one exemplary arrangement. More specifically, the device  2 , with the stent graft  4  carried thereon, is pre-loaded as described above in connection with  FIG. 2 , but it is contemplated that the device can be pre-loaded in a variety of acceptable ways, including, but not limited to, the configuration described and shown in connection with  FIG. 4  and/or a combined or modified version of one or more of the previously described configurations. 
       FIG. 8  shows the next stage of one example of a graft delivery and deployment sequence where the auxiliary sheath  26  is advanced over the auxiliary guide wire  40  so that the sheath enters the distal end  5  of the branched stent graft  4 . The auxiliary sheath  40  is further advanced over the auxiliary wire  40 , over stent bifurcation  42  and into the lumen of the side branch  36 , until the tip  28  of the auxiliary sheath  26  extends out of the distal end of branch  48 . (Or, alternatively, as described in connection with the embodiment shown in  FIG. 5 , the auxiliary sheath  26  would only be advanced a short distance into the proximal end portion  44  of the side branch lumen  36  until it abuts the interior lumen wall where the auxiliary wire  40  pierces and exits the branch lumen  36 .) At this stage, the auxiliary guide wire  40  is still preferably in place such that it extends out of the distal end  46  of the side branch  34  and runs distally along the outside of the stent graft  4  through the common iliac artery  48  where the wire re-enters the lumen at proximal end  12  of pusher catheter  10  and extends back to the distal external manipulation section  8  of the device  2 . 
     As shown in  FIGS. 3 and 9 , an additional stent graft or leg extension (ultimately intended for introduction and deployment in the internal iliac artery  52 ) is then preferably introduced into the internal iliac artery  52  using an ipsilateral approach. In one example, this may be accomplished by inserting a further delivery device  64  carrying a leg extension stent graft through the device  2 . More particularly, as  FIGS. 3 and 9  show, extension graft  66 , covered by an appropriately sized sheath  68  (so that the graft  66  is not visible in  FIGS. 3 and 9 ), is carried by further delivery device  64 , and the device  64  is preferably tracked through the lumen of the auxiliary sheath  26  so that the further delivery device  64  extend towards and into the side branch lumen  36 . As  FIG. 9  shows, the graft  66 , covered by sheath  68 , extends distally beyond the tip  28  of the auxiliary sheath  26  and can be manipulated so that it enters the internal iliac artery  52 . Preferably, as shown in  FIGS. 10 and 11 , extension graft  66  is positioned so that it extends both proximally and distally away from the location of aneurysm  60 , therefore, spanning and bypassing the diseased portion of the vessel  52 . At this stage, the further delivery device  64 , extension sheath  68 , and auxiliary sheath  26  can be withdrawn, preferably in a distal direction, from the common iliac artery  48 , leaving the graft  66  in place in the internal iliac artery  52 . 
     Further, as shown in  FIGS. 10 and 11 , the leg extension graft  66  preferably extends from the side branch  34  of the stent graft  4  into the internal iliac artery  52  and can be at least partially deployed in the internal iliac artery  52 . In one example, as shown in  FIG. 11 , the release mechanism(s) at one or both ends of the stent graft  4 , if present, can be released and the sheath  68  withdrawn from the leg extension graft  66  so that the branched stent graft  4  with the leg extension  66  is ready to be fully deployed in the common iliac artery  48  and internal iliac artery  52 , respectively. The device  2  can also be withdrawn, if desired, although in some situations, it may be desirable to leave one or more components, such as pusher catheter  10  and/or the sheath  16  in position within the common iliac artery  48  so that further introduction and deployment of a stent graft into the aorta  56 , such as a bifurcated stent graft, can be facilitated through the pusher  10  and/or sheath  16 . 
     Turning to  FIG. 12 , a perspective view of one suitable method of proximal retention of the stent graft  4  on the device  2  is shown, while  FIG. 13  shows a cross sectional view of the arrangement shown in  FIG. 12 . The guide wire catheter  24  extends to the nose cone dilator  20  and, in one example, the proximal end portion  3  of the stent graft  4  is retained onto the guide wire catheter  24  just distal of the nose cone dilator  20 . Retention may be by various means, and in one non-limiting example, may include one or more loops or stitches of suture material  70  which are engaged with a trigger wire  72  extending from an aperture in the guide wire catheter  24 . However, it is also contemplated that other types and methods of proximal restraint may be used including various diameter reducing ties, fasteners or the like that are suitable for removably securing the stent graft  4  on the device  2 . 
     The sutures  70  may be placed on one wall of the stent graft  4  or, alternatively, as shown in  FIG. 13 , may be placed on generally opposing walls of the tubular graft body  30 . The sutures  70  may be placed in any suitable arrangement or location so that the graft  4  is removably secured to the device  2 , and as  FIGS. 12 and 13  show, they may be placed so that there is formed a smaller and larger lobe or fold of the stent graft at its proximal end  3 . The proximal end  3  of the stent graft  4  may be released from this retention arrangement by releasing the one or more sutures  70 , or any other type of proximal retention mechanism that may be used in combination with or in place of such sutures, during deployment of the graft within a vessel lumen. 
       FIG. 14  shows a perspective view of one suitable method of distal retention of the stent graft on the device  2 . In this non-limiting example, the distal end  5  of the stent graft  4  may be retained onto the guide wire catheter  24  just proximal of the pusher catheter  10  by one or more sutures  74  which are engaged with a trigger wire  76  extending from an aperture in the guide wire catheter  24 . However, like the proximal retention mechanism described above, it is also contemplated that other types and methods of distal restraint may be used including various diameter reducing ties, fasteners or the like that are suitable for removably securing the stent graft on the introducer. In another example shown in  FIG. 15 , the trigger wire  76  may pierce or be woven through the distal end  5  of the stent graft  4  directly, thus, retaining the graft against the guide wire catheter  24  until the trigger wire(s)  76  is removed. Removal of the trigger wire(s)  76  when desired or required will release the distal retention mechanism, thereby facilitating at least partial deployment of the distal end  5  of the stent graft  4  within a vessel lumen. Alternatively, one of the retention mechanisms may not be present and the stent graft  4  may be removably retained on the device  2  by the proximal end retention mechanism alone. 
     It is also contemplated that the leg extension graft  66  may also preferably include proximal and/or distal retention mechanisms that secure it to the further delivery device  64 . Proximal and/or distal retention of graft  66  may include the same or similar retention mechanisms as those described above in connection with the retention of stent graft  4  on delivery device  2 , such that graft  66  may be retained on further delivery device  64  in a manner similar to that shown in  FIGS. 12-15 . Of course, other types and methods of proximal and/or distal restraint of extension graft  66  may be used including various diameter reducing ties, fasteners or the like that are suitable for removably securing the extension graft  66  on the further delivery device  64 . Proximal and/or distal retention of extension graft  66  may be in addition to or in combination with sheath  68  which also secures the graft  66  to further delivery device  64  and holds it in a radially inwardly compressed “pre-deployment” condition. 
     Once the proximal and/or distal retention mechanisms have been removed, the stent graft  4  and/or extension graft  66  may be radially expanded or deployed within the respective vessels. In one example, a “self-expanding” stent expands primarily based on its own expansive force without the need for further mechanical expansion. More particularly, a stent made of a shape-memory alloy such as Nitinol may allow the stent graft  4 ,  66  to return to a predetermined expanded configuration upon removal of a sheath (e.g., sheath  16  or  68 ) or other mechanism that maintains the stent graft in its compressed, pre-deployment configuration. In another example, stents made of materials such as stainless steel may expand on their own accord once released from constraints holding them in their compressed state. Alternatively, a stent graft  4 ,  66  may require further manipulation, mechanical or manual expansion, such as by balloon expansion by the user. In either case, it is contemplated that the stent graft  4 ,  66  may expand or deploy only partially within the vessel lumen after removal of one or both of the proximal and distal retention mechanisms, such that additional expansion of the stent graft may be desired or required, at which time the user may implement various known and acceptable techniques to fully deploy the stent graft  4 ,  66  in the main and/or branched vessel. Such fully deployed stent grafts  4  and  66  are illustrated in exemplary  FIG. 11 . 
     Thus, the pre-loaded delivery device described herein successfully facilitates the introduction, placement and deployment of a stent graft into one or more branched vessels using an ipsilateral approach, including, but not limited to a common iliac artery  48  and an internal iliac artery  52  extending therefrom, in order to treat and/or restore patency to one or both of such vessels. 
     Throughout this specification, unless the context requires otherwise, the words “comprise” and “include” and variations such as “comprising” and “including” will be understood to imply the inclusion of an item or group of items, but not the exclusion of any other item or group items. 
     While various examples of the invention have been described, it will be apparent to those of ordinary skill in the art that many more examples and implementations are possible within the scope of the invention. Furthermore, although various indications have been given as to the scope of this invention, the invention is not limited to any one of these but may reside in two or more of these combined together. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.