In-vivo biocompatibility evaluation of stents coated with a new biodegradable elastomeric and functional polymer.

Background: In-stent restenosis may be prevented by impregnating an antiproliferative agent in a polymer from a stent platform. This approach requires both an antiproliferative agent effective in small doses and a biocompatible polymer.

Methods: A series of new biodegradable elastomeric poly(ester-amide)(co-PEA) polymers having functional carboxyl groups for drug conjugation were synthesized from non-toxic building blocks. The in-vivo biocompatibility was tested in porcine coronary arteries, by comparing the polymer-coated stents with bare metal stents in 10 pigs.

Results: All animals survived until sacrifice 28 days later and follow-up angiography prior to sacrifice revealed identical diameter stenosis (21 +/- 23%) in both groups. Histology confirmed similar injury scores (0.34 +/- 0.34 compared with 0.34 +/- 0.32), inflammatory reaction (1.18 +/- 0.38 compared with 1.11 +/- 0.32) and area stenosis (26 +/- 17% compared with 28 +/- 22%).

Conclusions: This study suggests that the newly developed copoly(ester-amide) elastomers may be suitable for stent-based local drug delivery.