Method and system for fixation of endoluminal devices

Abstract

A system and method employs collar stents to implant an endoluminal device, such as a stent-graft, in a lumen. The system comprises at least one collar stent adapted to precondition a portion of the lumen for anchoring an endoluminal device having at least a portion adapted to be deployed radially within the collar stent. The method comprises first deploying one or more collar stents, and then deploying the endoluminal device radially within the one or more collar stents. In various embodiments, the collar stent may be radiopaque, may have inwardly protruding barbs for engaging the endoluminal device, and may have a region having a relatively low percentage of open area for bridging a portion of the main lumen having an intersecting lumen. The preconditioning step of implanting the collar stent may change the morphology of the lumen to more favorable morphology, such as from a non-circumferential geometry to a circumferential geometry.

What is claimed:  
     
         1 . A method for deploying an endoluminal device in a lumen, the method comprising the steps of: 
 (a) first deploying one or more collar stents in one or more anchor locations in the lumen; and then    (b) deploying the endoluminal device radially within the one or more collar stents.    
     
     
         2 . The method of  claim 1  further comprising allowing a period of time between steps (a) and (b) for intravascular tissue growth around the one or more collar stents.  
     
     
         3 . The method of  claim 2 , wherein the period of time is at least about 2 weeks.  
     
     
         4 . The method of  claim 1 , wherein the endoluminal device is a stent-graft having a distal end adapted to be deployed upstream relative to endoluminal fluid flow of one or more proximal ends of the stent-graft, wherein the method comprises implanting a first of the collar stents in a first of the anchor locations aligned with the distal end of the stent-graft.  
     
     
         5 . The method of  claim 4 , wherein the stent-graft has a single proximal end and the method further comprises implanting a second of the collar stents in a second of the anchor locations aligned with the single proximal end.  
     
     
         6 . The method of  claim 4 , wherein the stent-graft branches into at least two proximal portions, each portion having a proximal end, the method further comprising implanting a second of the collar stents in a second of the anchor locations aligned with a first proximal end of the stent-graft and implanting a third of the collar stents in a third of the anchor locations aligned with a second proximal end of the stent-graft.  
     
     
         7 . The method of  claim 6 , wherein the lumen is an aorta having a main body, one or more renal arteries that branch off of the main body at a renal intersection, a neck downstream of the renal intersection, and two iliac arteries that branch from the main body, the method comprising deploying the first collar stent in the neck, deploying the second collar stent in one of the iliac arteries, and deploying the third collar stent in another of the iliac arteries.  
     
     
         8 . The method of  claim 7 , wherein the first collar stent comprises a first region having a first stent geometry with a first percentage of open area, a second region having a second stent geometry with a second percentage of open area greater than the first percentage, and a third region having the third stent geometry with a third percentage of open area less than the second percentage, the second region located intermediate the first region and the third region, the method comprising implanting the first collar stent so that the second region bridges the renal intersection.  
     
     
         9 . The method of  claim 8 , wherein the second stent geometry comprises a set of bridging struts.  
     
     
         10 . The method of  claim 8 , wherein the third stent geometry is essentially identical to the first stent geometry.  
     
     
         11 . The method of  claim 1 , wherein a first of the collar stents comprises a first region having a first stent geometry with a first percentage of open area, a second region having a second stent geometry with a second percentage of open area greater than the first percentage, and a third region having a third stent geometry with a third percentage of open area less than the second percentage, the second region located intermediate the first region and the third region, the method comprising implanting the first collar stent so that the second region bridges a portion of the lumen where one or more branch lumen intersect the lumen.  
     
     
         12 . The method of  claim 11 , wherein the second stent geometry comprises a set of bridging struts.  
     
     
         13 . The method of  claim 11 , wherein the third stent geometry is essentially identical to the first stent geometry.  
     
     
         14 . The method of  claim 1 , wherein a first of the collar stents comprises a plurality of barbs that protrude radially inward from the stent, the method comprising implanting the endoluminal device so that the barbs engage the endoluminal device.  
     
     
         15 . The method of  claim 1 , wherein the lumen at the anchor location is initially non-circumferential, the method comprising implanting the collar stent to conform the anchor location to a circumferential geometry.  
     
     
         16 . The method of  claim 1 , wherein the lumen at the anchor location initially has an angular inflection, the method comprising implanting the collar stent to straighten the angular inflection.  
     
     
         17 . A method for implantation of a stent-graft in a lumen, the method comprising preconditioning a portion of the lumen by implanting a collar stent prior to implanting the stent-graft, and then implanting the stent-graft so that at least a portion of the stent-graft overlaps the collar stent.  
     
     
         18 . The method of  claim 17 , wherein the lumen has a first morphology, and the preconditioning step changes the first morphology to a second morphology closer to circumferential than the first morphology.  
     
     
         19 . The method of  claim 17 , wherein the collar stent has a greater radiopacity than the lumen such that implantation of the collar stent enhances viewability of the portion of the lumen.  
     
     
         20 . A system for implantation of an endoluminal device in a lumen, the system comprising: 
 at least one collar stent adapted to precondition a portion of the lumen for anchoring the endoluminal device; and    the endoluminal device having at least a portion adapted to be deployed radially within of the collar stent.    
     
     
         21 . The system of  claim 20 , wherein the endoluminal device comprises a stent-graft.  
     
     
         22 . The system of  claim 21 , wherein the stent-graft has a distal end and a proximal end, and the kit comprises a first collar stent for alignment with the distal end and a second collar stent for alignment with the proximal end.  
     
     
         23 . The system of  claim 21 , wherein the stent-graft has a distal end and branches into at least two proximal portions, each portion having a proximal end, the at least one collar stent comprises a first collar stent for alignment with the distal end, a second collar stent for alignment with a first proximal end, and a third collar stent for alignment with a second proximal end.  
     
     
         24 . The system of  claim 23 , wherein the stent-graft is adapted for deployment in an aorta having a main body, one or more renal arteries that branch off of the main body at a renal intersection, a neck downstream of the renal intersection, and two iliac arteries that branch from the main body, the first collar stent adapted to be deployed in the neck, the second collar stent adapted to be deployed in one of the iliac arteries, and the third collar stent adapted to be deployed in another of the iliac arteries.  
     
     
         25 . The system of  claim 24 , wherein the first collar stent comprises a first region having a first stent geometry with a first percentage of open area, a second region having a second stent geometry with a second percentage of open area greater than the first percentage, and a third region having the third stent geometry with a third percentage of open area less than the second percentage, the second region located intermediate the first region and the third region, the second region having a length sufficient to bridge the renal intersection.  
     
     
         26 . The system of  claim 25 , wherein the second stent geometry comprises a set of bridging struts.  
     
     
         27 . The system of  claim 25 , wherein the third stent geometry is essentially identical to the first stent geometry.  
     
     
         28 . The system of  claim 20 , wherein the collar stent comprises a first region having a first stent geometry with a first percentage of open area, a second region having a second stent geometry with a second percentage of open area greater than the first percentage, and a third region having the third stent geometry with a third percentage of open area less than the second percentage, the second region located intermediate the first region and the third region.  
     
     
         29 . The system of  claim 28 , wherein second stent geometry comprises a set of bridging struts.  
     
     
         30 . The system of  claim 28 , wherein the third stent geometry is essentially identical to the first stent geometry.  
     
     
         31 . The system of  claim 20 , wherein the collar stent comprises a plurality of barbs that protrude radially inward from the stent for engaging the endoluminal device.  
     
     
         32 . The system of  claim 20 , wherein the collar stent is radiopaque.  
     
     
         33 . The system of  claim 20 , wherein the collar stent has a radial strength sufficient to modify a morphology of the lumen into which it is adapted to be implanted.  
     
     
         34 . The collar stent of  claim 33 , wherein the radial strength is sufficient to change a non-circumferential morphology to a circumferential morphology, change an angularly inflected morphology to a straight morphology, or both.  
     
     
         35 . The system of  claim 20 , wherein the collar stent is uncoated.  
     
     
         36 . The system of  claim 20 , wherein the collar stent is coated with a material that encourages intravascular tissue growth.  
     
     
         37 . A collar stent for preconditioning a lumen for implantation of an endoluminal device overtop of the collar stent, the collar stent comprising a plurality of barbs that protrude radially inward from the stent adapted to engage the endoluminal device.  
     
     
         38 . A collar stent for preconditioning a first lumen for implantation of an endoluminal device radially within the collar stent, the collar stent comprising a first region having a first stent geometry with a first percentage of open area, a second region having a second stent geometry with a second percentage of open area greater than the first percentage, and a third region having the third stent geometry with a third percentage of open area less than the second percentage, the second region located intermediate the first region and the third region, the second region having a length sufficient to bridge a portion of the first lumen where one or more intersecting lumen meet the first lumen.  
     
     
         39 . The collar stent of  claim 38 , wherein the first lumen is an aorta and the intersecting lumen are renal arteries that intersect the aorta at a renal intersection, in which the collar stent intermediate region length is sufficient to bridge the renal intersection.  
     
     
         40 . The collar stent of  claim 38 , wherein the collar stent is radiopaque.  
     
     
         41 . The collar stent of  claim 38 , wherein the collar stent has a radial strength sufficient to modify a morphology of the lumen into which it is adapted to be implanted.  
     
     
         42 . The collar stent of  claim 41 , wherein the radial strength is sufficient to change a non-circumferential morphology to a circumferential morphology, change an angularly inflected morphology to a straight morphology, or both.  
     
     
         43 . The collar stent of  claim 38  further comprising a plurality of barbs that protrude radially inward from the stent for engaging the endoluminal device.  
     
     
         44 . A method for deploying an endoluminal device in a lumen having an anchor location with an inadequate amount of available fixation length in a wall of the lumen for implantation of the device, the method comprising the steps of: 
 (a) deploying a stent in the anchor location with a first portion of the stent in contact with the lumen wall and a second portion of the stent positioned radially inward of the lumen wall, leaving a gap between the stent and the wall;    (b) allowing passage of a sufficient period of time for intravascular tissue growth to fill-in the gap between the stent and the lumen wall to increase the available fixation length; and then    (c) deploying the endoluminal device radially inward of the stent.    
     
     
         45 . The method of  claim 44 , wherein the anchor location is in a neck of an aorta.