Endoprosthesis having multiple helically wound flexible framework elements
The present invention is directed to an implantable medical device having two or more flexible framework elements helically disposed around a common central axis. Each framework element has a configuration having a series of apices alternating in direction. The framework elements are arranged together in the helical winding so the apices are in a nested relationship. Adjacent apices are connected to one another with flexible linkage elements. Each linkage element follows a distinct pathway or course through the framework elements. The elements can each be made of the same or different materials.
1 . An implantable medical device comprising:
a first framework element having a length and a series of apices oriented in opposite directions along the length of the first framework element, wherein said first framework element is helically disposed around a common central axis;
a second framework element having a length and a series of apices oriented in opposite directions along the length of the second framework element, wherein said second framework element is helically disposed around the common central axis and positioned together with the first framework element so that apices of the first framework element and apices of the second framework element are located adjacent to one another;
a first flexible linkage element linking the first framework element to the second framework element along a first course; and
a second flexible linkage element linking the first framework element to the second framework element along a second course distinct from the first course.
2 . The implantable medical device of claim 1 wherein the first flexible linkage connects at least two adjacent apices of the first framework element and the second framework element.
3 . The implantable medical device of claim 1 wherein the second flexible linkage connects at least two adjacent apices of the first framework element and the second framework element.
4 . The implantable medical device of claim 1 wherein the first framework element is made of a material exhibiting different physical properties than those of the second framework element.
5 . The implantable medical device of claim 1 wherein the first flexible linkage is made of a material exhibiting different physical properties than those of the second flexible linkage.
6 . The implantable medical device of claim 1 wherein the first framework element has a cross-sectional profile exhibiting different physical properties than those of the second framework element.
7 . The implantable medical device of claim 1 wherein the first flexible linkage has a cross-sectional profile exhibiting different physical properties than those of the second flexible linkage.
8 . The implantable medical device of claim 1 further comprising a third framework element having a length and a series of apices oriented in opposite directions along the length of the third framework element.
9 . The implantable medical device of claim 8 further comprising a third flexible linkage element.
10 . The implantable medical device of claim 1 further comprising a covering.
11 . The implantable medical device of claim 10 further comprising a bioactive material releasably combined with said covering.
12 . An implantable medical device comprising:
a first framework element having a length and a series of apices oriented in opposite directions along the length of the first framework element, wherein said first framework element is helically disposed around a common central axis;
a second framework element having a length and a series of apices oriented in opposite directions along the length of the second framework element, wherein said second framework element is helically disposed around the common central axis and positioned together with the first framework element so that apices of the first framework element and apices of the second framework element are located adjacent to one another;
a first flexible linkage element linking the first framework element to the second framework element along a first course;
a second flexible linkage element linking the first framework element to the second framework element along a second course distinct from the first course; and
a covering placed on at least a portion of said device.
13 . The implantable medical device of claim 12 further comprising a bioactive material releasably combined with said covering.
14 . The implantable medical device of claim 12 wherein the first flexible linkage connects at least two adjacent apices of the first framework element and the second framework element.
15 . The implantable medical device of claim 12 wherein the second flexible linkage connects at least two adjacent apices of the first framework element and the second framework element.
16 . The implantable medical device of claim 12 wherein the first framework element is made of a material exhibiting different physical properties than those of the second framework element.
17 . The implantable medical device of claim 12 wherein the first flexible linkage is made of a material exhibiting different physical properties than those of the second flexible linkage.
18 . The implantable medical device of claim 12 wherein the first framework element has a cross-sectional profile exhibiting different physical properties than those of the second framework element.
19 . The implantable medical device of claim 12 wherein the first flexible linkage has a cross-sectional profile exhibiting different physical properties than those of the second flexible linkage.
20 . The implantable medical device of claim 12 further comprising a third framework element having a length and a series of apices oriented in opposite directions along the length of the third framework element.
21 . The implantable medical device of claim 20 further comprising a third flexible linkage element.