Abstract 4713: Stent Degradation of Novel Fully Bioabsorbable Salicylate-Based Sirolimus-Eluting Stent: Assessment by Optical Coherence Tomography in Pig Coronary Artery
Background: Fully biodegradable stent is an alternative strategy for permanent metallic stents. We evaluated fully bioabsorbable sirolimus-eluting stent synthesized from salicylic-acid polymer in a pig model. In vitro studies showed sirolimus elution over 30 days and complete stent degradation in 9 –12 months.
Methods: Bioabsorbable stents (n=33) were implanted in pig coronaries using quantitative angiography to optimize stent apposition. Pigs were underwent restudy and terminated at 1 month (1M), 3 month (3M), 6 month (6M) and for histopathology. Thickness and area of each strut (implant: 1273 struts, 1M: 640 struts, 3M: 585 struts and 6M: 625 struts) were measured. And Intensity of each strut was also measured by OCT.
Results: Average strut thickness and area at 1M was similar to post implantation (implant: 0.25±0.001mm, 0.14±0.018mm2, 1M: 0.26±0.002mm, 0.12±0.002mm2, respectively, P=NS,). Strut Thickness and area gradually decreased over time (3M: 0.23±0.002mm and 0.09±0.002mm2, respectively, P<0.0001; 6M: 0.186±0.001mm and 0.07±0.001mm2, respectively, P<0.0001). On the other hands, once OCT signal intensity gradually become lower from 1M to 3M (1M: 6.06±0.019W, 3M; 5.92±0.020W, P<0.001), then gradually become higher from 3M to 6 M again (6M: 6.16±0.017W, P<0.001). Histopathology demonstrated gradual decrease in the size of strut void through 6 M and some tissue infiltrated to inside of the stent strut at 6M.
Conclusions: Degradation of fully bioabsorbable salicylate-based stent and replacement by neointimal tissue proliferation were illustrated by OCT. The size of this stent was decreased from 1M to 3M, 6M.