Medical devices having a bioresorbable coating layer with a pre-determined pattern for fragmentation
Intravascular medical devices comprising a coating layer disposed on a substrate associated with the medical device, wherein the coating layer has a pre-determined fragmentation pattern. At least a portion of the coating layer comprises a plurality of discontinuous bioresorbable members, wherein the discontinuous bioresorbable members have a size less than the luminal diameter of an arteriole. The coating layer may be formed by excavating portions of a coating layer (e.g., by laser ablation) to create gaps which define the discontinuous bioresorbable members. In certain embodiments, the coating layer is formed of a heat-bondable material. In such embodiments, the discontinuous bioresorbable members may be adhered to the substrate via heat bonds. Also disclosed are methods of forming a coating layer on medical devices and methods of treating intravascular sites.
1. An intravascular medical device comprising:
a coating layer disposed on a substrate associated with the medical device;
wherein at least a portion of the coating layer comprises a plurality of discontinuous bioresorbable members that define a preferential pattern of fragmentation upon degradation of the coating layer, and wherein the discontinuous bioresorbable members have a size less than the luminal diameter of an arteriole.
2. The medical device of claim 1 , wherein the discontinuous bioresorbable members have a size less than 30 μm.
3. The medical device of claim 1 , wherein the discontinuous bioresorbable members have a size less than 10 μm.
4. The medical device of claim 1 , wherein the discontinuous bioresorbable members have a size approximately that of a red blood cell or smaller.
5. The medical device of claim 1 , wherein the substrate is another coating over a surface of the medical device.
6. The medical device of claim 1 , wherein the substrate is a surface of the medical device.
7. The medical device of claim 1 , wherein the coating layer comprises a polymer.
8. The medical device of claim 7 , wherein the polymer is a bioresorbable polymer.
9. The medical device of claim 1 , wherein the coating layer comprises a heat-bondable material.
10. The medical device of claim 9 , wherein the substrate comprises a heat-bondable material.
11. The medical device of claim 10 , wherein the substrate comprises a polymer.
12. The medical device of claim 9 , wherein at least some of the discontinuous bioresorbable members have heat-bonded portions at the interface of the discontinuous bioresorbable members and the substrate.
13. The medical device of claim 1 , wherein the substrate has a non-smooth surface.
14. The medical device of claim 13 , wherein at least some of the discontinuous bioresorbable members have interlocking portions that mechanically interlock with the non-smooth surface of the substrate.
15. The medical device of claim 1 , wherein the coating layer contains a therapeutic agent.
16. A method of forming a coating layer on a medical device, comprising:
disposing a coating layer on a substrate associated with the medical device; and
excavating portions of the coating layer to form a plurality of discontinuous bioresorbable members in the coating layer, wherein the discontinuous bioresorbable members define a preferential pattern of fragmentation upon degradation of the coating layer, and wherein the discontinuous bioresorbable members have a size less than the luminal diameter of an arteriole.
17. The method of claim 16 , wherein the discontinuous bioresorbable members have a size less than 30 μm.
18. The method of claim 16 , wherein the discontinuous bioresorbable members have a size less than 10 μm.
19. The method of claim 16 , wherein the discontinuous bioresorbable members have a size approximately that of a red blood cell or smaller.
20. The method of claim 16 , wherein the step of excavating is performed using an energetic beam.
21. The method of claim 20 , wherein the coating layer comprises a heat-bondable material, and wherein the step of excavating further comprises heating a localized area of the coating layer and/or substrate.
22. The method of claim 21 , wherein the step of heating the localized area results in the formation of heat bonds at the interface of the discontinuous bioresorbable members and the substrate.
23. A method of treating an intravascular site, comprising:
(a) providing a medical device comprising:
a coating layer disposed on a substrate associated with the medical device;
wherein at least a portion of the coating layer comprises a plurality of discontinuous bioresorbable members that define a preferential pattern of fragmentation upon degradation of the coating layer, and wherein the discontinuous bioresorbable members have a size less than the luminal diameter of an arteriole;
(b) delivering the medical device to the intravascular site.
24. The method of claim 23 , wherein the step of delivering the medical device further comprises implanting the medical device at the intravascular site.
25. The method of claim 23 , wherein the coating layer comprises a therapeutic agent.
26. The method of claim 23 , wherein the discontinuous bioresorbable members have a size less than 30 μm.
27. The method of claim 23 , wherein the discontinuous bioresorbable members have a size less than 10 μm.
28. The method of claim 23 , wherein the discontinuous bioresorbable members have a size approximately that of a red blood cell or smaller.