Implantable medical device having reduced chance of late inflammatory response
AssigneeAbbott Cardiovascular Systems Inc.
InventorsBin Huang, David C. Gale
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Abstract
The invention provides a method for fabricating an implantable medical device to increase biocompatibility of the device, the method comprising: heat setting a polymer construct, wherein the polymer construct is at a temperature range of from about Tg to about 0.6(Tm−Tg)+Tg such that the set polymer construct comprises a crystalline structure having crystals at a size less than about 2 microns; and fabricating an implantable medical device from the heat set polymer construct.
Claims8
1-18. (canceled)
A biodegradable stent comprising:
- a cylindrically-shaped scaffold comprising a biodegradable polymer including a poly(L-lactide) based polymer,
- wherein the scaffold includes a pattern comprising a network of interconnected struts, the pattern formed by cutting a tube including the poly(L-lactide) based polymer,
- wherein a crystallinity of the tube is increased by processing, the processing comprising heating and radially expanding the tube prior to forming the pattern,
- wherein the scaffold has induced molecular orientation in the circumferential direction due to the radially expanding,
- wherein the biodegradable polymer after the processing has a crystallinity between 5% and 60% and comprises crystals dispersed in an amorphous domain, the crystals having a size less than 10 microns, and
- wherein the scaffold is radially expandable and has adequate radial strength from the increased crystallinity and induced circumferential orientation to hold open a blood vessel in a body when the scaffold is radially expanded in a blood vessel.
A method of treating atherosclerotic stenosis in a blood vessel with a biodegradable stent comprising:
- identifying a patient in need of treatment of atherosclerotic stenosis having an atherosclerotic segment in a blood vessel;
- and
- expanding the segment with a biodegradable stent including a cylindrically-shaped scaffold comprising a biodegradable polymer including a poly(L-lactide) based polymer,
- wherein the scaffold includes a pattern comprising a network of interconnected struts, the pattern formed by cutting a tube including the poly(L-lactide) based polymer,
- wherein the biodegradable polymer of the scaffold has a crystallinity between 5% and 60% and comprises crystals that are less than 2 microns dispersed in an amorphous domain,
- wherein when the amorphous domain is preferentially eroded compared to the crystals, the crystals that are left behind of less than 2 microns are small enough to be digested by macrophages which reduces a late inflammatory reaction, and
- wherein the scaffold has adequate radial strength from the crystallinity to hold open the blood vessel.
Dependencies are inferred from the claim text.