Billowing graft assemblies formed form one or more advantageously selected structural features

Abstract

A prosthetic device for the treatment of an anatomic organ in a patient is provided. The prosthetic device includes a main body having a height and a circumference and formed from a plurality of circumferentially extending wires and configured for being received in the organ of the patient, wherein the main body defines a portion extending along a length thereof that has a reduced hoop stress relative to the remainder of the main body when in a relaxed state and a covering extending over the main body and forming a billowing recess along the length of the frame in the main body due to the portion having reduced hoop stress. The anatomic organ may be an aorta of a patient.

What is claimed is: 
     
         1 . A prosthetic device for the treatment of an anatomic organ in a patient, the device comprising:
 a main body having a height and a circumference and formed from a plurality of circumferentially extending wires and configured for being received in the organ of the patient, wherein the main body defines a portion extending along a length thereof that has a reduced hoop stress relative to a remainder of the main body when in a relaxed state; and   a covering extending over the main body and forming a billowing recess along the length thereof due to the portion having reduced hoop stress.   
     
     
         2 . The prosthetic device of  claim 1 , wherein the main body is formed from a wire frame having leg portions connected at respective apices and bases, wherein the wire frame forms a Z stent frame. 
     
     
         3 . The prosthetic device of  claim 2 , wherein at least one pair of respective leg portions defines a structural feature of one of a height between a respective apex and base of the respective leg portions that is different from a height of the remaining apices and bases. 
     
     
         4 . The prosthetic device of  claim 2 , wherein a distance between two respective apices or bases is different than the distance between the apices and bases of the remaining leg portions. 
     
     
         5 . The prosthetic device of  claim 1 , wherein the portion having a reduced hoop stress comprises a portion of reduced thickness wire frame relative to the remaining wire frame of the main body. 
     
     
         6 . The prosthetic device of  claim 1 , wherein the portion having a reduced hoop stress has a metal forming process applied thereto in order to form the portion having a reduced hoop stress. 
     
     
         7 . The prosthetic device of  claim 6  wherein the metal forming process is electropolishing a portion of the main body to form the portion having a reduced hoop stress. 
     
     
         8 . The prosthetic device of  claim 1 , wherein the covering has a circumference that is larger than that of the main body when the main body is in a relaxed state. 
     
     
         9 . The prosthetic device of  claim 1 , wherein one or more stent or graft members are aligned longitudinally within the billowing recess. 
     
     
         10 . The prosthetic device of  claim 1 , wherein the billowing recess is formed adjacent the portion having a reduced hoop stress. 
     
     
         11 . The prosthetic device of  claim 1 , wherein the main body defines two portions extending along a length thereof that have a reduced hoop stress relative to the remainder of the main body when in a relaxed state, and further wherein two billowing recesses are formed along respective lengths of the main body due to the portion having reduced hoop stress. 
     
     
         12 . The prosthetic device of  claim 1 , wherein the main body is configured for engaging with a further stent or graft member at a proximal end thereof. 
     
     
         13 . The prosthetic device of  claim 1 , wherein the main body is configured for engaging with a further stent or graft member at a distal end thereof. 
     
     
         14 . The prosthetic device of  claim 1 , wherein the cover is oversized relative to the circumference of the main body. 
     
     
         15 . The prosthetic device of  claim 1 , wherein the portion having a reduced hoop stress comprises a portion made from a different material than the remainder of the main body. 
     
     
         16 . The prosthetic device of  claim 15 , wherein the different material is crimped with the remainder of the main body to form a continuous wire frame. 
     
     
         17 . A method of forming a stent comprising:
 determining a desired structural characteristic of at least two portions of a stent frame main body that collectively form the entirety of the frame;   selecting a construction of a first portion and a construction of a second portion; and   forming the stent with the first portion and the second portion,   wherein the main body defines a portion extending along a length thereof that has a reduced hoop stress relative to the remainder of the main body when in a relaxed state.   
     
     
         18 . The method of  claim 17 , wherein selecting a construction of the first portion includes electropolishing the first portion in a different manner than electropolishing the second portion. 
     
     
         19 . The method of  claim 17 , wherein selecting a construction of the first portion includes selecting a different material than a second material selected for the second portion. 
     
     
         20 . The method of  claim 18 , wherein selecting a different material includes selecting a material having a different thickness or thickness selected for the second portion. 
     
     
         21 . The method of  claim 17 , wherein selecting a construction of a first portion includes selecting a different frequency of apices for the first portion than selected for the second portion. 
     
     
         22 . The method of  claim 17 , wherein selecting a construction of a first portion includes selecting a greater height distance between respective apices than selected for the second portion. 
     
     
         23 . The method of  claim 17 , wherein selecting a construction of a first portion includes selecting one portion of a frame having a sharper bend in a respective apex than the bend in a respective apex of the second portion.