Covered endoprosthesis and delivery system
View Patent ↗The present invention is an improved endovascular device particularly useful for use in transjugular intrahepatic portosystemic shunt (TIPS) procedures. The device employs a two-part stent-graft construction that provides a low permeability membrane to line the shunt and an uncovered stent portion designed to reside in the portal vein. The device provides numerous benefits over previous stents and stent-grafts used in TIPS procedures, including being more compact to deliver, being easier to accurately deploy, a controlled compacted surface with tucked apices, an improved stent winding pattern, and being more flexible in delivery and use.
1. An endoprosthesis comprising
a cover on at least a portion of a stent element, the cover including a fluoropolymer film that is substantially impermeable to both air and water, such impermeability comprising an air impermeability time measurement of greater than 60 seconds per 100 cc air per 1 cm 2 of material at 1.2 kPa differential pressure and a water entry pressure through the cover of at least 5 psi (34 KPa).
2. The endoprosthesis of claim 1 wherein the cover includes a stored length.
3. The endoprosthesis of claim 1 wherein the cover comprises expanded polytetrafluoroethylene.
4. The endoprosthesis of claim 3 wherein the stent element includes at least a first segment and a second segment, and wherein the cover is attached to only the first segment.
5. The endoprosthesis of claim 4 wherein the second segment includes an interlocked stent pattern that resists uncontrolled elongation.
6. The endoprosthesis of claim 1 wherein the cover includes a structure having stored length, assisting the covered first segment in bending without kinking.
7. The endoprosthesis of claim 1 wherein the endoprosthesis is delivered at a compacted diameter and the endoprosthesis self-expands to an enlarged deployed diameter.
8. The endoprosthesis of claim 7 wherein the endoprosthesis at its compacted diameter is no more than 12 French.
9. The endoprosthesis of claim 7 wherein the stent element is folded into multiple pleats in its compacted diameter.
10. The endoprosthesis of claim 9 wherein
the stent element comprises a series of forward facing and rearward facing undulations; and
one series of undulations is folded within the pleats.
11. The endoprosthesis of claim 1 wherein the stent element has a radial stiffness of at least 0.1 kg/mm of diameter with a 1 cm wide loop-test.
12. The endoprosthesis of claim 1 wherein the cover has a thickness of no more than 0.4 mm.