Method for implanting a stent graft

Abstract

A delivery system and method for implanting a stent graft prostheses includes and employs a torque component at a distal end of the stent graft prosthesis, whereby following advancement of the stent graft to a surgical site in a constrained or partially constrained configuration, torque is applied to the torque component and, consequently, to the stent graft to rotationally align the stent graft about a longitudinal axis of the stent graft, followed by deployment of the stent graft in correct rotational alignment, and subsequent retraction of the delivery device from the deployed stent graft and the subject. The torque component includes a pushrod and at least two arms.

What is claimed is: 
     
         1 . A method of implanting a stent graft at an aneurysm site of a subject, comprising the steps of:
 a) directing a stent graft to an aneurysm site of the subject, the stent graft being held in a constricted position by a radial constraint, and extending circumferentially about a guidewire catheter that extends distally from a distal handle of a longitudinal body of a delivery device and is within the stent graft, the stent graft having a proximal end and a distal end, and wherein the distal end of the stent graft is rotationally fixed relative to a torque component, the torque component including a pushrod extending about the guidewire catheter and at least two arms and extending distally and radially from the pushrod, each arm being moveable from a constricted state to an expanded state, whereby the torque component exhibits radial expansion;   b) rotating a proximal handle of the longitudinal body to thereby rotate the pushrod and rotationally align the stent graft within the aneurysm site;   c) retracting the radial constraint, thereby releasing the stent graft at the aneurysm site; and   d) retracting the guidewire catheter and the torque component from the subject, thereby implanting the stent graft at the aneurysm site of the subject.   
     
     
         2 . The method of  claim 1 , wherein the radial constraint of the delivery device includes an introducer sheath that extends distally from the longitudinal body and about the stent graft, and wherein the stent graft, prior to being directed to the aneurysm site, is constrained within the introducer sheath, and further including the step of at least partially exposing the stent graft, whereby the stent graft radially expands to a second constrained position prior to the step of rotating the proximal handle and the pushrod to thereby rotationally align the stent graft within the aneurysm. 
     
     
         3 . The method of  claim 2 , wherein the stent graft is at least partially exposed by advancing the stent graft from the introducer sheath and from a position distal to the aneurysm site to the aneurysm site. 
     
     
         4 . The method of  claim 2 , wherein the stent graft is at least partially exposed by retracting the introducer sheath from the stent graft. 
     
     
         5 . The method of  claim 1 , wherein at least a portion of the arms of the torque component are articulated. 
     
     
         6 . The method of  claim 1 , wherein the torque component further includes a hub linking the pushrod to the at least two or arms, the hub defining a lumen about the longitudinal axis and wherein each of the at least two arms, when viewed at an angle normal to the longitudinal axis of the hub, has a curvilinear shape in the expanded state. 
     
     
         7 . The method of  claim 1 , wherein the radial constraint includes at least one thread and wire combination, and a flexible sheath extending about the stent graft, whereby the stent graft can be released from radial constraint by retracting the wire from the thread or the flexible sheath toward the longitudinal body. 
     
     
         8 . The method of  claim 7 , wherein the radial constraint includes both the thread and wire combination, and the flexible sheath extending about the stent graft, whereby the stent graft can be released from constraint by removing the flexible sheath in one stage, and the wire can be withdrawn from the thread in another stage. 
     
     
         9 . The method of  claim 1 , wherein at least one of the arms defines an opening at a distal end, whereby a suture in the stent graft can be threaded through the opening, and a wire extending from the longitudinal body and through the suture secures the stent graft to the arm, whereby retraction of the wire toward the handle releases the stent graft from the arm. 
     
     
         10 . The method of  claim 1 , further including an apex capture catheter extending distally from the distal handle of the longitudinal body and about the guidewire catheter, the apex capture catheter being moveable between a first position and a second position, and an apex capture device having a distal capture component at the distal end of the guidewire catheter, and a proximal capture component at a distal end of the apex capture catheter, wherein the distal capture component and the proximal capture component together define an interior space that captures a proximal stent of the stent graft when the apex capture catheter is in the second position. 
     
     
         11 . The method of  claim 1 , wherein the radial constraint of the delivery device includes an introducer sheath extending about and constraining the torque component and the stent graft, the introducer sheath being retractable from the stent graft and at least a portion of the torque component by at least one of retraction of the introducer sheath and advancement of the pushrod and guidewire catheter. 
     
     
         12 . The method of  claim 1 , further including a nose cone at the distal end of the guidewire catheter. 
     
     
         13 . The method of  claim 1 , wherein each arm has a cross section that has radial height less than a width at the cross section along at least a portion of a length of the at least one arm. 
     
     
         14 . The method of  claim 1 , wherein two arms extend distally from the pushrod. 
     
     
         15 . The method of  claim 14 , wherein each of the two arms are evenly spaced relative to each other about a longitudinal axis of the pushrod. 
     
     
         16 . The method of  claim 1 , wherein three arms extend distally from the pushrod. 
     
     
         17 . The method of  claim 16 , wherein each of the three arms are evenly spaced relative to each other about a longitudinal axis of the pushrod. 
     
     
         18 . The method of  claim 1 , wherein four arms extend distally from the pushrod. 
     
     
         19 . The method of  claim 18 , wherein each of the four arms are evenly spaced relative to each other about a longitudinal axis of the pushrod. 
     
     
         20 . The method of  claim 1 , wherein the stent graft includes a proximal end captured at the interior space of an apex capture assembly and a distal end extending about the arms, and wherein the stent graft is radially constrained by the radial constraint. 
     
     
         21 . The method of  claim 20 , wherein the stent graft includes a suture that secures at least a portion of the arms from rotational movement relative to the stent graft, whereby the torque component is substantially prevented from rotating within the stent graft before deployment. 
     
     
         22 . A method of implanting a stent graft at an aneurysm site of a subject, comprising the steps of:
 a) advancing a stent graft that is maintained in a constricted state by a radial constraint to an aneurysm site;   b) rotationally aligning the stent graft by rotation of the stent graft with at least partial assistance of a torque component at a distal end of the stent graft; and   c) removing the radial constraint from the stent graft, thereby implanting the stent graft at the aneurysm site.   
     
     
         23 . A method of implanting a stent graft at an aneurysm of a subject, comprising the steps of:
 a) directing a stent graft to an aneurysm of the subject, the stent graft including a luminal graft component and a plurality of radial stents distributed longitudinally along the luminal graft component, at least one of the stents having struts that are joined to define proximal and distal apices, the stent graft being held in a constrained position by a radial constraint, the radial constraint including at least one ligature traversing at least a portion of the struts of the stents of the stent graft, the ligature including ends that, when linked, at least partially radially constrict the stents, the radial constraint also including a wire extending longitudinally along the luminal graft component and linking the ligature ends and thereby radially constricting at least a portion of the stents of the stent graft, whereby retraction of the wire from the ends of the at least one ligature releases the radial constriction by the at least one ligature; and extending circumferentially about a guidewire catheter that extends distally from a distal handle of a longitudinal body of a delivery device and is within the stent graft, the stent graft having a proximal end and a distal end, and wherein the distal end of the stent graft is rotationally fixed relative to a torque component fixed to a pushrod that extends proximally from and circumferentially about the guidewire catheter and within the stent graft;   b) rotating a proximal handle of the longitudinal body to thereby rotate the pushrod and rotationally align the stent graft within the aneurysm site;   c) retracting the radial constraint, thereby releasing the stent graft at the aneurysm site; and   d) retracting the guidewire catheter and the torque component from the subject, thereby implanting the stent graft at the aneurysm site of the subject.   
     
     
         24 . The method of  claim 23  further including a pair of anchor loops at the luminal graft component that longitudinally span the ends of each associated ligature when linked to radially constrict the corresponding stent. 
     
     
         25 . The method of  claim 24 , wherein at least a portion of the ligatures are each circular and are linked at diametrically opposed points by the wire threading the anchor loops when the ligature is radially constricting the luminal graft component. 
     
     
         26 . The method of  claim 23 , wherein the radial constraint includes at least one of a thread and wire combination, and a flexible sheath extending about the stent graft, whereby the stent graft can be released from constraint by withdrawing the wire from the thread or the flexible sheath from the stent graft. 
     
     
         27 . The method of  claim 26 , wherein the radial constraint includes both of the thread and wire combination, and the flexible sheath extending about the stent graft, whereby the stent graft can be released from constraint by removing the flexible sheath in one stage, and the wire can be withdrawn from the thread in another stage.