Abstract:
An introduction arrangement for a fenestrated or branched stent graft ( 13 ) intended for deployment into the lumen of a vessel having a blind vessel extending from it. The introducer ( 1 ) has a distal end intended to remain outside a patient in use and a proximal end with a nose cone dilator ( 11 ) and an arrangement to retain the branched stent graft distally of the nose cone dilator. A sheath ( 15 ) on the introducer extends over the branched stent graft to the nose cone dilator. An indwelling catheter ( 22 ) extends from the distal end of the introducer and enters the fenestration or side arm and through to the nose cone dilator, the indwelling catheter has a guide wire ( 29 ) extending through it. The guide wire can be extended beyond the nose cone dilator in use before the sheath is withdrawn from the branched stent graft so that it can be snared from the contra-lateral artery.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation of U.S. Ser. No. 13/181,249 filed Jul. 12, 2011, which is a Division of U.S. Ser. No. 10/962,763, filed Oct. 12, 2004, now U.S. Pat. No. 8,012,193, and claims priority to provisional applications Ser. No. 60/510,823 filed Oct. 14, 2003 and Ser. No. 60/601,485 filed Aug. 13, 2004, all of which are incorporated by reference herein in their entireties. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to a medical device and more particularly to a medical device adapted for deployment of a stent graft within a human or animal body. 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention will be generally discussed in relation to deployment of a stent graft into an iliac artery where it is necessary to extend a side branch from a stent graft into an internal iliac artery but it is to be understood that the invention is not so limited and may relate to any body lumen in which such a deployment is required. 
         [0004]    Throughout this specification the term distal with respect to a portion of the aorta, a deployment device or a prosthesis is the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart and the term proximal means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood. 
         [0005]    Stent grafts are used for treatment of vasculature in the human or animal body to bypass a repair or defect in the vasculature. For instance, a stent graft may be used to span an aneurism which has occurred in or associated with the iliac artery. In many cases, however, such a damaged or defective portion of the vasculature may include a branch vessel such as an internal iliac artery. Bypassing such a branch vessel without providing blood flow into it can cause problems and hence it has been proposed to provide a side branch on a stent graft which when deployed is positioned over the opening to the internal iliac artery and then another stent graft can be deployed through the side branch into the internal iliac artery to provide a blood flow path to the internal iliac artery. 
         [0006]    Generally, when deploying an endovascular stent graft into a body lumen, it is possible to obtain access to such a body lumen from each end of the lumen where necessary, thereby facilitating placement of a device in the lumen. The internal iliac artery which extends from the common iliac artery below the aortic bifurcation is for all intents and purposes a blind vessel because there is no practical way of performing an endovascular minimally invasive procedure into that vessel other than by entry from the common iliac artery. The term blind vessel is used herein to describe such a vessel. 
         [0007]    There have been proposals to deploy a branched stent graft into the common iliac artery via a femoral artery from a femoral incision with the branched stent graft having a side arm to extend into or at least adjacent the internal iliac artery, however, the use of such devices is very dependent upon favourable layout of the arteries and in many cases, access is extremely difficult. This invention proposes an alternative method for approaching the common iliac artery and a deployment device to enable such a method to be practised. 
         [0008]    It is the object of this invention therefore to provide an improved deployment device or at least to provide a physician with a useful alternative. 
       SUMMARY OF THE INVENTION 
       [0009]    In one form therefore, although this may not necessarily be the only or broadest form, the invention is said to reside in an arrangement for introducing a stent graft into an internal iliac artery, the arrangement having means to enable a guide wire to be extended so that it can be snared from a contra-lateral iliac artery so as to enable access to the internal iliac artery via an aortic bifurcation from the contra-lateral iliac artery. 
         [0010]    Generally it will be seen that by the use of such a device, the deployment of a stent graft into the internal iliac is more favourable when approached from the aortic bifurcation because the geometry of the branch between the common iliac artery and the internal iliac artery is more favourable when approached from that direction. 
         [0011]    In an alternative form, the invention is said to reside in an introducer device having arrangement for retaining a stent graft thereon, an indwelling catheter having a guide wire therethrough associated with the introducer device, the indwelling catheter extending to the proximal end of the introducer device whereby the guide wire can be advanced beyond the proximal end of the introducer device so that it can be snared. 
         [0012]    By this arrangement, the guide wire can be extended beyond the introducer device so that it can be snared from the contra-lateral iliac artery and drawn over the aortic bifurcation and down the contra-lateral iliac artery so that the guide wire can be used to enter the internal iliac artery from over the aortic bifurcation. 
         [0013]    Preferably the stent graft is of a type which includes a fenestration or a branch extending therefrom and the indwelling catheter extends through the fenestration or branch whereby a deployment device for a side arm can be deployed over the guide wire, once snared, to enter the fenestration or branch so that the side arm can be deployed into and extending from the fenestration or branch. 
         [0014]    In a further form, the invention is said to reside in an introduction arrangement for a branched stent graft intended for deployment into the lumen of a vessel having a blind vessel extending therefrom; the branched stent graft having a main tubular body having a distal end and a proximal end with a main lumen therethrough, a side arm extending from the main body and having a side arm lumen therethrough and in fluid communication with the main lumen, the introduction arrangement including an introducer, the introducer having a distal end intended to remain outside a patient in use and a proximal end, the proximal end having a nose cone dilator and an arrangement to retain the branched stent graft distally of the nose cone dilator, the branched stent graft being retained on the introducer and a sheath on the introducer extending over the branched stent graft to the nose cone dilator, an indwelling catheter extending from the distal end of the introducer through an introducer lumen in the introducer to the branched stent graft; exiting from the introducer lumen at a distal end of the branched stent graft and entering the distal end of the side arm through the side arm lumen to the main lumen and extending out of the proximal end of the branched stent graft to the nose cone dilator, the indwelling catheter having a guide wire extending therethrough, whereby the guide wire can be extended beyond the nose cone dilator in use before the sheath is withdrawn from the branched stent graft. 
         [0015]    It will be noted that by this form of introducer and branched stent graft assembly the indwelling catheter is external of the stent graft for part of its extent but during deployment it is covered by the introducer sheath. 
         [0016]    It will be seen that by this arrangement, an introducer can be introduced into an artery such as an iliac artery and before the stent graft is exposed by retraction of the sheath the guide wire can be extended beyond the nose cone dilator to enable it to be snared from the contralateral iliac artery and then the guide wire can be used as will be discussed below for deployment of a leg extension or side arm stent graft into the internal iliac artery. 
         [0017]    Preferably the nose cone dilator has a longitudinal groove thereon to receive the indwelling catheter. 
         [0018]    The means to retain the branched stent graft on the introducer may include trigger wires extending to the distal end of the introducer and release arrangements for separate release of the proximal and distal ends of the stent graft from the introducer. 
         [0019]    In a further form the invention is said to reside in an introducer device and a stent graft retained thereon, the stent graft comprising a tubular body and a fenestration in the tubular body, an indwelling catheter having a guide wire extending therethrough and associated with the introducer device, the indwelling catheter extending through the stent graft and the fenestration and to the proximal end of the introducer device whereby the guide wire can be advanced beyond the proximal end of the introducer device so that it can be snared and a deployment device for a side arm can be deployed over the guide wire, once snared, to enter the fenestration. 
         [0020]    Preferably the stent graft has a proximal end and a distal end and the indwelling catheter extends outside of the stent graft distally of the fenestration and through the fenestration into the stent graft and towards the proximal end. 
         [0021]    The fenestration can includes a side arm extending therefrom towards either the proximal or distal ends thereof. Alternatively the side arm extending from the fenestration extends inside the stent graft towards either the proximal or distal ends thereof. 
         [0022]    The indwelling catheter can extend inside of the stent graft distally of the fenestration and through the fenestration out of the stent graft and towards the proximal end thereof. 
         [0023]    In an alternative form the invention is said to reside in an introduction arrangement for a fenestrated graft intended for deployment into the lumen of a vessel having a blind vessel extending therefrom; the fenestrated stent graft having a main tubular body having a distal end and a proximal end with a main lumen therethrough, a fenestration in the main body, the introduction arrangement including an introducer, the introducer having a distal end intended to remain outside a patient in use and a proximal end, the proximal end having a nose cone dilator and an arrangement to retain the fenestrated stent graft distally of the nose cone dilator, the fenestrated stent graft being retained on the introducer and a sheath on the introducer extending over the fenestrated stent graft to the nose cone dilator, an indwelling catheter extending from the distal end of the introducer through an introducer lumen in the introducer to the fenestrated stent graft, exiting from the introducer lumen at a distal end of the fenestrated stent graft and entering the fenestration to the main lumen and extending out of the proximal end of the fenestrated stent graft to the nose cone dilator, the indwelling catheter having a guide wire extending therethrough, whereby the guide wire can be extended beyond the nose cone dilator in use before the sheath is withdrawn from the fenestrated stent graft. 
         [0024]    U.S. Pat. No. 5,387,235 entitled “Endovascular Transluminal Prosthesis For Repair Of Aneurysms” discloses apparatus and methods of retaining grafts onto deployment devices. These features and other features disclosed in U.S. Pat. No. 5,387,235 could be used with the present invention and the disclosure of U.S. Pat. No. 5,387,235 is herewith incorporated in its entirety into this specification. 
         [0025]    U.S. Pat. No. 5,720,776 entitled “Barb and Expandable Transluminal Graft Prosthesis For Repair of Aneurysm” discloses improved barbs with various forms of mechanical attachment to a stent. These features and other features disclosed in U.S. Pat. No. 5,720,776 could be used with the present invention and the disclosure of U.S. Pat. No. 5,720,776 is herewith incorporated in its entirety into this specification. 
         [0026]    U.S. Pat. No. 6,206,931 entitled “Graft Prosthesis Materials” discloses graft prosthesis materials and a method for implanting, transplanting replacing and repairing a part of a patient and particularly the manufacture and use of a purified, collagen based matrix structure removed from a submucosa tissue source. These features and other features disclosed in U.S. Pat. No. 6,206,931 could be used with the present invention and the disclosure of U.S. Pat. No. 6,206,931 is herewith incorporated in its entirety into this specification. 
         [0027]    PCT Patent Publication No. WO98/53761 entitled “A Prosthesis and a Method of Deploying a Prosthesis” discloses an introducer for a prosthesis which retains the prosthesis so that each end can be moved independently. These features and other features disclosed in PCT Patent Publication No. WO98/53761 could be used with the present invention and the disclosure of PCT Patent Publication No. WO98/53761 is herewith incorporated in its entirety into this specification. 
         [0028]    U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262 entitled “Endoluminal Aortic Stents” disclose a fenestrated prosthesis for placement where there are intersecting arteries. This feature and other features disclosed in U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262 could be used with the present invention and the disclosure of U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262 is herewith incorporated in its entirety into this specification. 
         [0029]    U.S. patent application Ser. No. 10/280,486, filed Oct. 25, 2002 and published on May 8, 2003 as U.S. Patent Application Publication No. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 entitled “Prostheses For Curved Lumens” discloses prostheses with arrangements for bending the prosthesis for placement into curved lumens. This feature and other features disclosed in U.S. patent application Ser. No. 10/280,486, and U.S. Patent Application Publication No. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 could be used with the present invention and the disclosure of U.S. patent application Ser. No. 10/280,486, and U.S. Patent Application Publication No. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 is herewith incorporated in its entirety into this specification. 
         [0030]    U.S. Provisional Patent Application Ser. No. 60/392,682, filed Jun. 28, 2002, U.S. patent application Ser. No. 10/447,406, filed May 29, 2003, and Published on Dec. 18, 2003, as U.S. Patent Application Publication No. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518 entitled “Trigger Wires” disclose release wire systems for the release of stent grafts retained on introducer devices. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/392,682, U.S. patent application Ser. No. 10/447,406, and U.S. Patent Application Publication No. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/392,682, U.S. Patent Application Serial No. 10/447,406, and U.S. Patent Application Publication No. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518 is herewith incorporated in its entirety into this specification. 
         [0031]    U.S. Provisional Patent Application Ser. No. 60/392,667, filed Jun. 28, 2002, and U.S. patent application Ser. No. 10/609,846, filed Jun. 30, 2003, and Published on May 20, 2004, as US Patent Application Publication No. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 entitled “Thoracic Deployment Device” disclose introducer devices adapted for deployment of stent grafts particularly in the thoracic arch. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/392,667, U.S. patent application Ser. No. 10/609,846, and US Patent Application Publication No. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/392,667, U.S. patent application Ser. No. 10/609,846, and US Patent Application Publication No. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 is herewith incorporated in its entirety into this specification. 
         [0032]    U.S. Provisional Patent Application Ser. No. 60/392,599, filed Jun. 28, 2002, and U.S. patent application Ser. No. 10/609,835, filed Jun. 30, 2003, and published on Jun. 3, 2004, as U.S. Patent Application Publication No. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 entitled “Thoracic Aortic Aneurysm Stent Graft” disclose stent grafts that are useful in treating aortic aneurysms particularly in the thoracic arch. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No 60/392,599, U.S. patent application Ser. No. 10/609,835, and U.S. Patent Application Publication No. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 could be used with the present invention, and the disclosure of U.S. Provisional Patent Application Ser. No. 60/392,599, U.S. patent application Ser. No. 10/609,835, and U.S. Patent Application Publication No. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 is herewith incorporated in its entirety into this specification. 
         [0033]    U.S. Provisional Patent Application Ser. No. 60/391,737, filed Jun. 26, 2002, U.S. patent application Ser. No. 10/602,930, filed Jun. 24, 2003, and published on Mar. 18, 2004, as U.S. Patent Application Publication No. US-2004-0054396-A1, and PCT Patent Publication No. WO 2004/002365 entitled “Stent-Graft Fastening” disclose arrangements for fastening stents onto grafts particularly for exposed stents. This feature and other features disclosed in U.S. Provisional Patent Application No. 60/391,737, U.S. patent application Ser. No. 10/602,930, and U.S. Patent Application Publication No. US-2004-0054396-A1, and PCT Patent Publication No. WO 2004/002365 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/391,73, U.S. patent application Ser. No. 10/602,930, and U.S. Patent Application Publication No. US-2004-0054396-A1, and PCT Patent Publication No. WO 2004/002365 is herewith incorporated in its entirety into this specification. 
         [0034]    U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23,2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25, 2003, and PCT Patent Publication No. WO 2004/017868 entitled “Asymmetric Stent Graft Attachment” disclose retention arrangements for retaining onto and releasing prostheses from introducer devices. This feature and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25, 2003, and PCT Patent Publication No. WO 2004/017868 could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23, 2002, U.S. Patent Application Ser. No. 10/647,642, filed Aug. 25, 2003, and PCT Patent Publication No. WO 2004/017868 are herewith incorporated in its entirety into this specification. 
         [0035]    U.S. Patent Application Ser. No. 10/322,862, filed Dec. 18, 2002 and published as Publication No. US2003-0120332, and PCT Patent Publication No. WO003/053287 entitled “Stent Graft With Improved Adhesion” disclose arrangements on stent grafts for enhancing the adhesion of such stent grafts into walls of vessels in which they are deployed. This feature and other features disclosed in U.S. patent application Ser. No. 10/322,862, filed Dec. 18, 2002 and published as Publication No. US2003-0120332, and PCT Patent Publication No. WO03/053287 could be used with the present invention and the disclosure of U.S. patent application Ser. No. 10/322,862, filed Dec. 18, 2002 and published as Publication No. US2003-0120332, and PCT Patent Publication No. WO03/053287 are herewith incorporated in its entirety into this specification. 
         [0036]    U.S. Provisional Patent Application Ser. No. 60/405,769, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/645,095, filed Aug. 23, 2003, and PCT Patent Publication Number WO 2004/017867 entitled “Composite Prostheses” discloses prostheses or stent grafts suitable for endoluminal deployment. These prostheses and other features disclosed in U.S. Provisional Patent Application Ser. No. 60/405,769, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/645,095, filed Aug. 23, 2003, and PCT Patent Publication Number WO 2004/017867, could be used with the present invention and the disclosure of U.S. Provisional Patent Application Ser. No. 60/405,769, filed Aug. 23, 2002, U.S. patent application Ser. No. 10/645,095, filed Aug. 23, 2003, and PCT Patent Publication Number WO 2004/017867 are herewith incorporated in its entirety into this specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0037]    This then generally describes the invention but to assist with the understanding, reference will now be made to the accompanying drawings which show a preferred embodiment of the invention and a method by which the preferred embodiment of the invention may be used to deploy a stent graft into the internal iliac artery. 
           [0038]    In the drawings; 
           [0039]      FIGS. 1 to 6  show the various stages of deployment of a stent graft on a deployment device into an iliac artery according to one embodiment of the present invention; 
           [0040]      FIG. 7  shows a schematic view of a deployment device with a stent graft mounted thereon according to one embodiment of the invention;  FIG. 8  shows a schematic view of a deployment device with a stent graft mounted thereon according to an alternative embodiment of the invention; 
           [0041]      FIG. 9  shows a further schematic view of the deployment device shown in  FIG. 8 ; 
           [0042]      FIG. 10  shows a stage of deployment of the stent graft as shown in  FIGS. 8 and 9  corresponding to the stage of deployment shown in  FIG. 5  above; 
           [0043]      FIG. 11  shows a schematic view of a deployment device with a stent graft mounted thereon according to a further embodiment of the invention; 
           [0044]      FIG. 12  shows a side view of one method of proximal retention suitable for the present invention; 
           [0045]      FIG. 13  shows a cross sectional view of the arrangement shown in  FIG. 12 ; 
           [0046]      FIG. 14  shows a side view of one method of distal retention suitable for the present invention; and 
           [0047]      FIG. 15  shows a side view of an alternative method of distal retention suitable for the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0048]    Now looking first at  FIG. 7 , the introducer with a stent graft mounted onto it according to one embodiment of the present invention is shown schematically. 
         [0049]    The introducer generally shown as  1  has an introducer catheter  3  extending over a guide wire catheter  5 . The guide wire catheter  5  extends from the distal end  7  of the introducer  1  to immediately distal of the nose cone dilator  11 . A branched stent graft  13  is retained at its proximal end by a retention arrangement (see  FIGS. 12 and 13  for one example of a proximal retention arrangement) onto the introducer immediately distal of the nose cone dilator  11 . The branched stent graft  13  is retained at its distal end by another retention arrangement (see  FIGS. 14 and 15  for examples of a proximal retention arrangement) onto the introducer. A sleeve  15  operated by a sleeve manipulator  17  is mounted on the introducer catheter  3  and in the ready to deploy position the sleeve  15  extends over the branched stent graft  13  to the nose cone dilator  11 . As illustrated in  FIG. 7 , however, the sleeve  15  is withdrawn so that the branched stent graft is exposed to show detail of the assembly. A handle  19  at the distal end of the introducer catheter  3  enables manipulation of the introducer  1 . An indwelling catheter  21  enters a lumen (not shown) of the introducer catheter  3  at the handle  19  and exits from the introducer catheter  3  at the distal end  23  of the branched stent graft  13 . 
         [0050]    The branched stent graft  13  has a substantially tubular body with a main lumen through the main tubular body and a side lumen through the branch  25 . The indwelling catheter  21  enters the lumen of the branch  25  from its distal end  26  and hence it passes outside the main tubular body of the branched stent graft before it enters the branch lumen. The indwelling catheter then exits from the main body adjacent the nose cone dilator and extends along the side of the nose cone dilator in a groove  27  in the nose cone dilator. 
         [0051]    Within the indwelling catheter  21 , there is a guide wire  29 . This guide wire  29  can be pushed through the indwelling catheter so that it extends beyond the tip  31  of the nose cone dilator so that it can be snared as will be discussed in relation to  FIGS. 1 to 6  showing one embodiment of the stent graft placement procedure. Preferably the tip  32  of the indwelling catheter is tapered around the guide wire  29  to prevent blood loss through the indwelling catheter. 
         [0052]    Now looking at  FIGS. 1 to 6 , it will be seen that there is schematically illustrated a series of arteries within the human body, although as discussed earlier, the invention is not restricted to this particular application. 
         [0053]    A descending aorta  40  extends down to an aortic bifurcation  42  from which extend common iliac arteries  44  and  46 . From each of the common iliac arteries an internal iliac artery  48  and  50 , respectively, extends. As discussed earlier, the internal iliac arteries  48  and  50  cannot be practically accessed from their distal ends remote from the junction with the common iliac artery. 
         [0054]    As shown in  FIG. 1 , a guide wire  50  for the deployment device  52  has been extended into a femoral artery via a femoral incision (not shown) and extended up beyond the aortic bifurcation  42  to the aorta  40 . The introducer  1  has then been deployed over the guide wire with the nose cone dilator  11  extending nearly up to the aortic bifurcation. At this stage, the sleeve  15  on the deployment device extends up to the nose cone dilator  11  but has been withdrawn slightly to expose the proximal end  32  of the indwelling catheter  21 . 
         [0055]    As can be seen in  FIG. 2 , the guide wire  29  from the indwelling catheter  21  has been extended so that it extends up beyond the aortic bifurcation but only a short distance up the aorta  40 . A snare catheter  52  has been deployed via the contra-lateral iliac artery  46  and by suitable radiographic techniques the loop  54  of the snare catheter  52  is used to catch the guide wire  29 . 
         [0056]      FIG. 2A  shows an alternative step in the process. I this step the indwelling catheter  21  and the guide wire  29  have been advanced together to the aortic bifurcation  42  and so that the indwelling catheter  21  is beyond the nose cone dilator  11 . The guide wire  29  is then advance so that it can be snared by the loop  54  of the snare catheter. By this alternative step the guide wire  29  is held more firmly and there is less likelihood that it will become entangled with the main guide wire  50 . 
         [0057]    As shown in  FIG. 3 , the guide wire  29  has been withdrawn through the contra-lateral iliac artery  46  and the indwelling catheter  21  has been advanced over the guide wire so that it extends over the aortic bifurcation  42  and down the contra-lateral iliac artery  46 . To assist this process, the sheath  15  has been withdrawn to the distal end  23  of the branched stent graft  13  so that it is just distal of the proximal end of the introducer catheter  3 . At this stage the branched stent graft  13  is partially freed but is still retained by retention arrangements at at least the proximal and distal ends of the branched stent graft and is hence in an unexpanded or not fully expanded condition. 
         [0058]      FIG. 4  shows the next stage of the process where a sheath  58  of a suitable size has been advanced over the guide wire  29  via the contra-lateral artery and indwelling catheter  21  so that it enters the proximal end  60  of the branched stent graft  13 . At this stage, the indwelling catheter and guide wire  29  still extends down the iliac artery  44  on the introducer  1  so that the sheath  58  can be manipulated to successfully enter the proximal end of the branched stent graft so that it extends towards and into the branch  25  on the stent graft  13 . At this stage, the indwelling catheter  21  and guide wire  19  can be withdrawn either from the contra-lateral iliac artery  46  or from the iliac artery  44  and another guide wire  62  introduced via the sheath  58 . This guide wire  62  can then be manipulated so that it enters the internal iliac artery  48 . 
         [0059]    As shown in  FIG. 5 , a further deployment device  63  can then be introduced via the sheath  58  from the contra-lateral iliac artery  46  to extend out of the distal end of the branch  25  of the branched stent graft  13  so that a leg extension  64  can be deployed to extend from the branch  25  of the branched stent graft  13 . 
         [0060]    As shown in  FIG. 6 , the sheath  58  from the contra-lateral iliac artery  46  can then be withdrawn and the release mechanisms at each end of the stent graft  13  can be released and the leg extension  64  released so that the branched stent graft with leg extension is then deployed in the common iliac artery. 
         [0061]    The introducer  1  can then be withdrawn although in some situations it may be desirable to leave the sleeve  15  in position so that further deployment of a stent graft into the aorta such as a bifurcated stent graft can be achieved through the sheath  15 . 
         [0062]    In summary therefore, the steps in the graft placement procedure accordingly using the device of the present invention may be as follows: 
         [0063]    1. Deploy an introducer into a femoral artery via a femoral incision and extend the introducer up to the aortic bifurcation. 
         [0064]    2. Withdraw the sheath to expose the proximal end of an indwelling catheter associated with the introducer. 
         [0065]    3. Advance an indwelling guide wire through the indwelling catheter beyond the nose cone dilator of the introducer. 
         [0066]    4. Introduce a snare catheter into the contra-lateral iliac artery via a femoral route and snare the indwelling guide wire. 
         [0067]    5. Withdraw the indwelling guide wire through the contra-lateral iliac artery and advance the indwelling catheter around the aortic bifurcation to protect the aortic bifurcation during subsequent steps. 
         [0068]    6. Withdraw the main sheath to expose the branched stent graft but still have the branched stent graft retained at each of its ends. 
         [0069]    7. Deploy an auxiliary sheath over the indwelling guide wire up the contra-lateral iliac artery and into the branched stent graft via the proximal end of the branched stent graft. 
         [0070]    8. Advance the auxiliary sheath into the short leg of the branched stent graft via the indwelling catheter guide wire or another guide wire which has been deployed through the sheath which has been placed via the contra-lateral iliac artery. 
         [0071]    9. Remove the indwelling catheter and indwelling guide wire. 
         [0072]    10. Advance a guide wire through the auxiliary sheath via the contra-lateral iliac artery and manipulate it into the internal iliac artery. At this stage, it may be necessary to withdraw the deployment device or rotate it slightly to guide the branch of the branched stent graft towards the internal iliac artery. 
         [0073]    11. Advance a short leg introducer with a leg stent graft over the guide wire in the contra-lateral iliac artery and through the auxiliary sheath and into the internal iliac artery. 
         [0074]    12. Release the proximal distal ends of the branched stent graft 
         [0075]    13. Release the leg stent graft from the short leg introducer or balloon expand the leg stent graft. 
         [0076]    14. Withdraw the contra-lateral iliac artery auxiliary sheath, introducer and guide wire. 
         [0077]    15. Withdraw the main introducer. 
         [0078]    As discussed earlier it may be necessary or desirable to leave the sheath of the main introducer and/or the main guide wire to enable deployment of further stent grafts within the aorta and aortic bifurcation. 
         [0079]    Now looking at  FIGS. 8 and 9 , an introducer with a stent graft mounted onto it according to an alternative embodiment of the present invention is shown schematically. The same reference numerals are used for corresponding features to those of  FIG. 7 . 
         [0080]    The introducer generally shown as  1  has an introducer catheter  3  extending over a guide wire catheter  5 . The guide wire catheter  5  extends from the distal end  7  of the introducer  1  to immediately distal of the nose cone dilator  11  which is at the proximal end  9  of the introducer. A fenestrated stent graft  70  is retained by a retention arrangement (not shown) onto the introducer immediately distal of the nose cone dilator  11 . A sleeve  15  operated by a sleeve manipulator  17  is mounted on the introducer catheter  3  and in the ready to deploy position the sleeve  15  extends over the stent graft  70  to the nose cone dilator  11 . As illustrated in  FIG. 7 , however, the sleeve  15  is withdrawn so that the stent graft is exposed to show detail of the assembly. A handle  19  at the distal end of the introducer catheter  3  enables manipulation of the introducer  1 . An indwelling catheter  21  enters a lumen (not shown) of the introducer catheter  3  at the handle  19  and exits from the introducer catheter at the distal end  23  of the stent graft  70 . 
         [0081]    The stent graft  70  has a substantially tubular body with a main lumen through the main tubular body and a fenestration  71 . The indwelling catheter  21  enters the fenestration  71  from outside the stent graft and hence it passes outside the main tubular body of the stent graft at the distal end thereof, before it enters fenestration. The indwelling catheter then passes through the main lumen of the stent graft to its proximal end and exits from the main body adjacent the nose cone dilator  11  and extends along the side of the nose cone dilator in a groove  27  in the nose cone dilator. 
         [0082]    Within the indwelling catheter  21 , there is a guide wire  29 . This guide wire  29  can be pushed through the indwelling catheter so that it extends beyond the tip  31  of the nose cone dilator so that it can be snared as discussed in relation to  FIGS. 1 to 6  showing a stent graft placement procedure. Preferably the tip  32  of the indwelling catheter is tapered around the guide wire  29  to prevent blood loss through the indwelling catheter. 
         [0083]      FIG. 10  shows a stage of deployment of the stent graft as shown in  FIGS. 8 and 9  corresponding to the stage of deployment shown in  FIG. 5  above. The same reference numeral are used for corresponding features to those of  FIGS. 1 to 6 . 
         [0084]    Prior to the stage shown in  FIG. 10  a guide wire  50  for the deployment device  52  has been extended into a femoral artery via a femoral incision (not shown) and extended up beyond the aortic bifurcation  42  into the aorta  40 . An introducer  1  has then been deployed over the guide wire with the nose cone dilator  11  extending nearly up to the aortic bifurcation. At this stage, the sleeve  15  on the deployment device extends up to the nose cone dilator but has been withdrawn slightly to expose the proximal end of the indwelling catheter  21 . Next a guide wire from an indwelling catheter (not shown in  FIG. 10 ) has been extended so that it extends up beyond the aortic bifurcation but only a short distance up the aorta  40 . A snare catheter has been deployed via the contra-lateral iliac artery  46  and by suitable radiographic techniques the loop of the snare catheter has been used to catch the guide wire. The guide wire has then been withdrawn through the contra-lateral iliac artery  46  and the indwelling catheter has been advanced over the guide wire so that it extends over the aortic bifurcation  42  and down the contra-lateral iliac artery  46 . To assist this process, the sheath  15  has been withdrawn to just distal of the fenestration  25  and still covering the distal end  23  of the stent graft  70 . At this stage the stent graft  13  is partially freed but is still retained by a retention arrangements at the proximal end  60  of the stent graft and by the sheath at the distal end. The exposed portion of the stent graft between the proximal end and the fenestration can expand although there may be diameter reducing ties (not shown) to restrict the amount of expansion. Next a sheath  58  of a suitable size has been advanced over the guide wire  29  and indwelling catheter  21  so that it enters the proximal end  60  of the branched stent graft  70 . At this stage, the indwelling catheter and guide wire  29  still extends down the iliac artery  44  on the introducer  1  so that the sheath  58  can be manipulated to successfully enter the proximal end of the branched stent graft  60  so that it extends towards and into the fenestration  71  on the stent graft  70 . At this stage, the indwelling catheter  21  and guide wire  19  can be withdrawn, either from the contra-lateral iliac artery  46 , or from the iliac artery  44  and another guide wire  62  introduced via the sheath  58 . This guide wire  62  can then be manipulated so that it enters the internal iliac artery  48 . 
         [0085]    As shown in  FIG. 10 , a further deployment device  63  has then been introduced via the sheath  58  from the contra-lateral iliac artery  46  to extend out of the fenestration  71  of the stent graft  70 . The further deployment device  63  carries a leg extension  64 . The leg extension  64  can be deployed to extend from the fenestration  71  of the stent graft  70 . The leg extension  64  can be a covered balloon expandable stent for instance, which is carried on a balloon in the deployment device so that it can be deployed and expanded with its proximal end retained in the fenestration and extending into the internal iliac artery  48 . 
         [0086]    Now looking at  FIG. 11 , an introducer with a stent graft mounted onto it according to an alternative embodiment of the present invention is shown schematically. 
         [0087]    In this embodiment the stent graft  90  has a fenestration  94  in the wall of the stent graft  90  and an internal leg extension  92  extending inwardly and toward the proximal end  74  of the stent graft  90  from the fenestration  94 . The indwelling catheter  80  extends into the fenestration  94  and into the internal leg extension  92  and toward the proximal end  74  of the stent graft  90 . The indwelling catheter  80  then exits from the main body adjacent the nose cone dilator  82  and extends along the side of the nose cone dilator  82  in a groove  81  in the nose cone dilator  82 . 
         [0088]      FIGS. 8 to 11  show various embodiments of the present invention in a stylised manner. It should be noted that the configuration with the main sheath withdrawn completely off the stent graft but with the indwelling catheter and guide wire in its initial position would not occur in practice. 
         [0089]      FIG. 12  shows a side view of one method of proximal retention suitable for the present invention and  FIG. 13  shows a cross sectional view of the arrangement shown in  FIG. 12 . The same reference numerals are used for corresponding features to those of  FIG. 7  for corresponding items. 
         [0090]    The guide wire catheter  5  extends to a nose cone dilator  11  and the proximal end of the stent graft  13  is retained onto the guide wire catheter just distal of the nose cone dilator. Retention is by means of a pair loops of suture material  101  each of which is engaged with a trigger wire  103  extending from an aperture in the guide wire catheter  5 . The loops are placed so that there is formed a smaller  105  and larger fold  107  of the stent graft  13  at its proximal end. The indwelling catheter passes through the region defined by the larger fold  107  and therefore when the sheath  58  (see  FIG. 4 ) has been advanced over the guide wire then it can more easily enter the lumen of the stent graft. 
         [0091]      FIG. 14  shows a side view of one method of distal retention suitable for the present invention. The same reference numerals are used for corresponding features to those of  FIG. 7  for corresponding items. In this embodiment the distal end  23  of the stent graft  13  is retained onto the guide wire catheter  5  just proximal of the deployment catheter  3  by means of a suture loop  109  engaged into the stent graft  13  and a loop of trigger wire  111  extending from the deployment catheter  3 . Removal of the trigger wire  111  when required will release the distal end  23  of the stent graft  13 . 
         [0092]      FIG. 15  shows a side view of an alternative method of distal retention suitable for the present invention. The same reference numerals are used for corresponding features to those of  FIG. 7  for corresponding items. In this embodiment the distal end  23  of the stent graft  13  is retained onto the guide wire catheter  5  just proximal of the deployment catheter  3  by means a loop of trigger wire  113  extending from the deployment catheter  3  and passing through a portion of the stent graft  13 . Removal of the trigger wire  113  when required will release the distal end  23  of the stent graft  13 . 
         [0093]    Throughout this specification various indications have been given as to the scope of this invention but the invention is not limited to anyone of these but may reside in two or more of these combined together. The examples are given for illustration only and not for limitation. 
         [0094]    Throughout this specification and the claims that follow, 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 a stated integer or group of integers but not the exclusion of any other integer or group of integers.