Medical implant
Disclosed is a self-expanding medical implant for placement within a lumen of a patient. The implant comprises a woven or non-woven structure having a substantially tubular configuration, and is designed to be low-profile such that it is deliverable with a small diameter catheter. The implant has a high recoverability and desired mechanical properties.
1. An implantable medical device, comprising:
a self-expanding tubular structure comprising at least one strand comprising a first polymer characterized by a modulus of elasticity greater than about 1 GPa; and
a second polymer at least partially and conformally coating said strand, said second polymer being an elastomeric thermoset polymer characterized by a percent elongation to break that is greater than about 150 percent at 37° C.;
wherein the second polymer increases the mass of said self-expanding tubular structure by at least about 20 percent.
2. The implantable medical device of claim 1 , wherein said first polymer is biodegradable.
3. The implantable medical device of claim 2 , wherein said first polymer comprises poly(lactic acid co-glycolic acid).
4. The implantable medical device of claim 3 , wherein said poly(lactic acid co-glycolic acid) comprises at least about 75 weight percent of lactic acid.
5. The implantable medical device of claim 4 , wherein said poly(lactic acid co-glycolic acid) comprises about 85 weight percent of lactic acid.
6. The implantable medical device of claim 4 , wherein said second polymer is poly(lactic acid-co-caprolactone) comprising about 50 to 70 weight percent lactic acid, wherein said polymer is cross-linked.
7. The implantable medical device of claim 6 , wherein said poly(lactic acid-cocaprolactone) is crosslinked with hexamethylene diisocyanate.
8. The implantable medical device of claim 6 , wherein the number average molecular weight (Mn) of said second polymer is greater than about 24,000 Da and less than about 100,000 Da.
9. The implantable medical device of claim 3 , wherein said poly(lactic acid co-glycolic acid) comprises up to about 20 weight percent of lactic acid.
10. The implantable medical device of claim 1 , wherein said first polymer is characterized by a modulus of elasticity greater than about 6 GPa.
11. The implantable medical device of claim 1 , wherein said second polymer is biodegradable.
12. The implantable medical device of claim 11 , wherein said second polymer is a random copolymer that is crosslinked.
13. The implantable medical device of claim 11 , wherein said second polymer is selected from the group consisting of poly(lactic acid-co-caprolactone), poly(glycolide-co-caprolactone, poly trimethylene carbonate, and poly(lactic acid-co-dioxanone) and wherein said second polymer is cross-linked.
14. The implantable medical device of claim 1 , wherein said second polymer is characterized by an elastic segment having a glass transition temperature less than about 5, degree. C.
15. The implantable medical device of claim 1 wherein said self-expanding tubular structure is a braided structure.
16. The implantable medical device of claim 15 , wherein said braided structure comprises between 16 and 48 strands.
17. The implantable medical device of claim 16 , wherein said strands form an average braid angle of between about 90 degrees and about 135 degrees.
18. The implantable medical device of claim 17 , wherein said strands form an average braid angle of between about 110 degrees and about 135 degrees.
19. The implantable medical device of claim 1 , further comprising a therapeutic agent within at least one of said first polymer material and said second polymer material.
20. The implantable medical device of claim 1 , wherein the second polymer increases the mass of said self-expanding tubular structure by at least about 30 percent.
21. The implantable medical device of claim 1 , further comprising a third polymer at least partially coating said second polymer.
22. The implantable medical device of claim 21 , further comprising a therapeutic agent within said third polymer.
23. The implantable medical device of claim 1 , wherein said second polymer comprises a first segment having a Tg less than about 5.degree. C. and a second segment that is harder than the first segment.
24. The implantable medical device of claim 1 , wherein said self expanding tubular structure has a first end and a second end.
25. An implantable medical device, comprising:
a self-expanding tubular structure comprising:
at least one biodegradable strand comprising poly(lactic acid-co-glycolic acid) comprising at least 75 weight percent of lactic acid; and
poly(lactic acid-co-caprolactine) at least partially coating said strand;
wherein said poly9lactic acid-co-caprolactone) is cross-linked and has a number average molecular weight (Mn) greater than 30,000 Da;
wherein said poly(lactic acid co-caprolactone) increases the mass of said self-expanding tubular structure by at least 24 percent;
wherein said self-expanding tubular structure is a braided structure comprising between 16 and 48 strands forming an average braid angle of between 110 degrees and 135 degrees.