Mesh graft and stent for increased flexibility
View Patent ↗A composite stent-graft tubular prosthesis includes an inner PTFE tubular structure, an outer PTFE tubular structure positioned about the inner PTFE tubular structure and a diametrically deformable stent interposed between the inner and outer PTFE tubular structures. The interposed stent is formed from an elongate wire helically wound with a plurality of longitudinally spaced turns into an open configuration. Each of the turns includes successive aligned upper and lower wave-like peaks. Selective ones of said upper and lower peaks are exposed exteriorly of the outer PTFE structure to render the composite prosthesis longitudinally flexible.
1. A method of forming a stent-graft prosthesis comprising the step of:
forming a first PTFE tubular structure;
positioning a stent over said first PTFE tubular structure, said stent having a tubular configuration formed of a plurality of turns of a helically wound wire, each of said turns including successive upper and lower wave-like peaks;
forming a second PTFE tubular structure over said stent; and
exposing selective ones of said upper and lower wave-like peaks through said second PTFE tubular structure, wherein exposing includes placing a plurality of slits through said second PTFE tubular structure at a location aligned with said selective upper and lower peaks of said stent; and extending said upper and lower peaks of said stent through said slits.
2. A method of claim 1 further including the step of adheringly securing said first PTFE tubular stent to said second PTFE tubular structure through spaces between said wound wire.
3. A method of claim 2 wherein said extending step includes:
lifting said selective upper and lower peaks;
tucking a portion of said second PTFE tubular structure adjacent said slit, under said upper and lower peaks.
4. A method of claim 2 wherein said placing step includes:
cutting said slits using a cutting tool.
5. A method of claim 2 wherein said placing step includes:
laser burning said slits through said second PTFE tubular structure.
6. A method of claim 2 wherein said exposing step includes:
forming said second PTFE tubular structure with a plurality of apertures, said apertures being at a location adjacent said selective upper and lower peaks.
7. A method of claim 1 wherein said second PTFE tubular structure is sintered prior to said exposing step.
8. A method of claim 1 wherein said second PTFE tubular structure is sintered subsequent to said exposing step.