Variable depression stents (vds) and billowing graft assemblies

Abstract

A stent assembly includes support rings each having interconnected circumferentially alternating inner prongs and outer prongs. The inner prongs define an inner diameter around a longitudinal axis. The outer prongs define an outer diameter greater than the inner diameter. A graft engages the support rings and follows a waving peripheral path. The graft may be a billowing graft. A second graft may surround the first graft such that tunnels are defined between the first graft and second graft. A method of making a stent assembly includes diametrically expanding the support rings onto a mandrel, engaging a graft with the support rings, and removing the support rings and graft from the mandrel permitting the stent assembly to contract to a neutral state.

What is claimed is: 
     
         1 . A stent assembly comprising:
 a first support ring having interconnected circumferentially alternating first inner prongs and first outer prongs, the first inner prongs defining a first inner diameter around a central longitudinal axis, and the first outer prongs defining a first outer diameter around the central longitudinal axis greater than the first inner diameter;   a second support ring spaced from the first support ring along the central longitudinal axis, the second support ring having interconnected circumferentially alternating second inner prongs and second outer prongs, the second inner prongs defining a second inner diameter around the central longitudinal axis, and the second outer prongs defining a second outer diameter around the central longitudinal axis greater than the second inner diameter, wherein, in cooperation, a radially recessed portion of the first support ring and the second support ring defines at least one channel;   a billowing graft engaging at least a portion of one or more of the first support ring and the second support ring, the billowing graft following a waving peripheral path and creating longitudinal grooves at least partially around the at least one channel of the first support ring and second support ring, wherein at least one of the longitudinal grooves extends in a direction that is parallel to a direction of a central axis extending along a length of the stent assembly.   
     
     
         2 . The stent assembly according to  claim 1 , wherein:
 a circumferential position of a particular first inner prong is aligned with a circumferential position of a particular second inner prong;   circumferential positions of two first outer prongs adjacent the particular first inner prong are aligned respectively with circumferential positions of two second outer prongs adjacent the particular second inner prong such that the at least one longitudinal channel is defined along the aligned circumferential positions of the particular first inner prong and particular second inner prong.   
     
     
         3 . The stent assembly according to  claim 2 , wherein the billowing graft billows along the longitudinal channel. 
     
     
         4 . The stent assembly according to  claim 2 , wherein the billowing graft is selectively attached to the two first outer prongs adjacent the particular first inner prong and to the two second outer prongs adjacent the particular second inner prong. 
     
     
         5 . The stent assembly according to  claim 4 , wherein the billowing graft is free to billow radially outward from and radially inward toward the particular first inner prong along the longitudinal groove in response to pressurization from fluid flow therein. 
     
     
         6 . The stent assembly according to  claim 1 , further comprising at least one side stent positioned at least partially within the longitudinal groove. 
     
     
         7 . The stent assembly according to  claim 1 , wherein;
 the first inner prongs have tips directed in a first longitudinal direction; and   the first outer prongs have tips directed in a second longitudinal direction opposite the first longitudinal direction.   
     
     
         8 . The stent assembly according to  claim 7 , wherein the first support ring further has a portion defined by at least two prongs that extend in opposite longitudinal directions, the portion of the first support ring being equidistant from the central longitudinal axis. 
     
     
         9 . The stent assembly according to  claim 8 , wherein the first outer prongs and the at least two prongs of the portion of the first support ring are equidistant from the central longitudinal axis. 
     
     
         10 . The stent assembly according to  claim 8 , wherein the second support ring further has a portion defined by at least two prongs that extend in opposite longitudinal directions, the at least two prongs of the portion of the second support ring being equidistant from the central longitudinal axis. 
     
     
         11 . The stent assembly according to  claim 10 , wherein the portion of the first support ring has a circumferential position aligned with a circumferential position of the portion of the second support ring. 
     
     
         12 . The stent assembly according to  claim 11 , wherein an angle subtended partially around the central longitudinal axis by the portion of the first support ring is approximately equal to an angle subtended partially around the central longitudinal axis by the portion of the second support ring. 
     
     
         13 . The stent assembly according to  claim 12 , wherein the angle subtended partially around the central longitudinal axis by the portion of the first support ring is less than one hundred and eighty degrees. 
     
     
         14 . The stent assembly according to  claim 13 , wherein:
 the first inner prongs and first outer prongs are connected together by intermediate connecting segments; and   the first inner prongs, first outer prongs and intermediate connecting segments together subtend a summation angle of greater than one hundred and eighty degrees around the central longitudinal axis.   
     
     
         15 . The stent assembly according to  claim 13 , wherein:
 the first support ring comprises a first portion including the first inner prongs and first outer prongs and a second portion including a radially flat portion of the first support ring; and   the first portion of the first support ring is C-shaped and subtends an angle of greater than one hundred and eighty degrees around the central longitudinal axis.   
     
     
         16 . The stent assembly according to  claim 1 , wherein:
 the second inner prongs have tips directed in the first longitudinal direction; and   the second outer prongs have tips directed in the second longitudinal direction opposite the first longitudinal direction.   
     
     
         17 . The stent assembly according to  claim 1 , wherein:
 the second outer prongs have tips directed in the first longitudinal direction; and   the second inner prongs have tips directed in the second longitudinal direction opposite the first longitudinal direction.   
     
     
         18 . The stent assembly according to  claim 1 , wherein at least one fenestration for receiving a vessel is formed through the billowing graft. 
     
     
         19 . The stent assembly according to  claim 18 , further comprising a radio-opaque marker placed around the at least one fenestration. 
     
     
         20 . The stent assembly according to  claim 18 , wherein the at least one fenestration is formed through the billowing graft at a circumferential position corresponding to a circumferential position of a radially flat portion of the first support ring and a circumferential position of a radially flat portion of the second support ring. 
     
     
         21 . A prosthetic device for the treatment of abdominal aortic aneurysms in a patient, comprising:
 a main body formed from a plurality of circumferentially extending wires and configured for being received in an abdominal artery of the patient, wherein the main body includes a graft member covering the circumferentially extending wires and the graft member defines one or more longitudinally extending grooves, the longitudinally extending grooves expandable radially upon pressurization and configured for engaging with a stent member along a length thereof.   
     
     
         22 . The device according to  claim 21 , wherein, the one or more grooves are formed when the prosthetic device is in a relaxed state, and when the prosthetic device is in an expanded state, the one or more grooves of the at least one grooves expands radially such that at least a portion of the prosthetic device defines a generally continuous arcuate surface extending between adjacently positioned grooves. 
     
     
         23 . The device according to  claim 21 , wherein, a longitudinally extending stent that is configured for allowing fluid flow therethrough extends within at least one groove of the one or more grooves. 
     
     
         24 . The device according to  claim 23 , wherein the stent is placed within the at least one groove while the prosthetic device is in a relaxed state, and the longitudinally extending channel is secured within the at least one groove when the prosthetic device is in an expanded state and secured within the abdominal artery of the patient. 
     
     
         25 . The device according to  claim 23 , wherein the at least one groove extends beyond at least two adjacent rows of circumferentially extending wires. 
     
     
         26 . The device according to  claim 24 , wherein the prosthetic device is in the expanded state in response to pressure from fluid flow within the abdominal artery of the patient. 
     
     
         27 . The device according to  claim 22 , wherein the at least one groove is defined when the prosthetic device is in the relaxed state, and the at least one groove is not defined when the prosthetic device is in an expanded state. 
     
     
         28 . The device according to  claim 21 , wherein the circumferentially extending wires are engaged with the graft member, and the circumferentially extending wires have a relaxed state which causes formation of the at least one groove about an inner radially facing portion of the circumferentially extending wires. 
     
     
         29 . The device according to  claim 28 , wherein pressure from fluid flow within the prosthetic device causes outward expansion of the graft member and the one or more longitudinal grooves such that at least one groove of the one or more grooves is no longer defined. 
     
     
         30 . The device according to  claim 21 , wherein at least one of the longitudinally extending grooves extends in a direction that is parallel to a direction of a central axis extending along a total length thereof. 
     
     
         31 . A prosthetic device for treatment of abdominal aortic aneurisms in a patient, comprising:
 a main body for being receiving in an abdominal artery of the patient, the main body including a plurality of circumferentially extending wires;   a graft member at least partially engaged with the plurality of circumferentially extending wires,   wherein the circumferentially extending wires form at least one portion that extends radially inward when the device is in a relaxed state and the graft member is engaged to the at least one portion to form a longitudinal groove in the graft member at the at least one portion;   wherein, after implantation in the abdominal artery, pressurization from fluid flow expands the longitudinal groove into engagement with the abdominal artery.   
     
     
         32 . The prosthetic device according to  claim 31 , wherein a stent member is placed between the longitudinal groove and the abdominal artery.