Medical implants
Disclosed are self-expanding medical implants for placement within a lumen of a patient. The implants comprise a woven or non-woven structure having a substantially tubular configuration, and are designed to be low-profile such that they are deliverable with a small diameter catheter. The implants have a high recoverability and desired mechanical properties.
1. A medical implant comprising:
a tubular structure being characterized, as manufactured and when unconstrained, by a first diameter and comprising a first polymeric material;
a conformal coating comprising a second polymeric material, said coating at least partially coating said tubular structure;
wherein said coating increases the mass of said tubular structure by at least 15%;
wherein said tubular structure is characterized by a radial resistive force that does not decrease by more than 50% after being placed into a configuration that is 55% to 90% of said first diameter in an aqueous environment at 37° C. for eight weeks.
2. The medical implant of claim 1 , wherein said second polymeric material is a thermoset elastomer.
3. The medical implant of claim 2 , wherein said thermoset elastomer is a polyester urethane.
4. The medical implant of claim 3 , wherein the thermoset elastomer is poly (lactic acid-co-caprolactone).
5. The medical implant of claim 4 , wherein said poly (lactic acid-co-caprolactone) comprises about 50weight percent of lactic acid and about 50 weight percent of caprolactone.
6. The medical implant of claim 2 , wherein said thermoset elastomer is prepared by a process that comprises the steps of:
at least partially dissolving a polyester polymer in a solvent to form a solution;
adding a diisocyanate crosslinker to said solution;
adding a chain terminator to said solution; and
curing said solution.
7. The medical implant of claim 6 , wherein said diisocyanate crosslinker is hexamethylene diisocyanate.
8. The medical implant of claim 6 , wherein said chain terminator comprises a monoisocyanate.
9. The medical implant of claim 8 , wherein said monoisocyanate is 1-dodecylisocyanate.
10. The medical implant of claim 6 , wherein said chain terminator comprises a monoalcohol.
11. The medical implant of claim 10 , wherein said monoalcohol is 1-dodecanol.
12. The medical implant of claim 2 , wherein said first polymeric material comprises poly(lactic acid co-glycolic acid).
13. The medical implant of claim 6 , wherein said thermoset elastomer comprises at least 1.5 wt % of said chain terminator.
14. The medical implant of claim 13 , wherein said thermoset elastomer comprises at least 2.0 wt % of said chain terminator.
15. The medical implant of claim 13 , wherein said thermoset elastomer comprises at least 4.0 wt % of said chain terminator.
16. The medical implant of claim 1 , wherein said tubular structure is characterized by a chronic outward force that does not decrease by more than 50% after being placed into a configuration that is 55% to 90% of said first diameter in an aqueous environment at 37° C. for twelve weeks.
17. The medical implant of claim 1 , wherein said tubular structure is characterized by a radial resistive force that does not decrease by more than 50% after being placed into a configuration that is not greater than 75 % of said first diameter in an aqueous environment at 37° C. for twelve weeks.
18. The medical implant of claim 17 , wherein said tubular structure is characterized by a chronic outward force that does not decrease by more than 50% after being placed into a configuration that is not greater than 75% of said first diameter in an aqueous environment at 37° C. for twelve weeks.
19. The medical implant of claim 1 , wherein said tubular structure is characterized by a chronic outward force that does not decrease by more than 25% after being placed into a configuration that is 55% to 90% of said first diameter in an aqueous environment at 37° C. for eight weeks.