TCT-458: Which Genes of the Nitric Oxide Pathway Contribute to Vascular Dysfunction Following DES Implantation in Swine Coronary Arteries?

Background: Thrombosis remains a risk following all types of endovascular intervention. Though considerable advances have been made in stent design, the design factors leading to stent thrombosis—stent design, drug elution, and coatings—continue to be improved and evaluated. It is critical that stents exhibit minimal surface thrombogenicity to reduce the incidence of device-induced vessel thrombosis. Methods: The left and right femoral artery of five domestic Yorkshire swine were cannulated to create to an ex vivo blood shunt through polyethylene tubing with silicone tubing sections to allow stent deployment before re-entry to the femoral vein. 3.0x18mm stents in the following groups were evaluated: bare metal stent (BMS, ML VISION®), collagen coated BMS (BMS-c), XIENCE V® (XV), and Endeavor Resolute (Res), and unstented silicone tubing (negative control). Six stents from each group were inserted into the ex-vivo shunt system randomized in sequence. No anticoagulation or antiplatelet agents were administered to the animals. Blood was allowed to circulate through the shunt for 30 minutes, following which stents were weighted for gravimetric assessment of thrombus burden and images were obtained. Results: As expected, positive control collagen coated BMS exhibited the greatest amount of thrombus, followed by BMS, then Endeavor Resolute. Xience V and unstented silicone tubing had the least thrombus. The pre-stenting to post-stenting weight differential of each was—BMS: 0.06±0.04, BMS-c: 0.10±0.02, Res: 0.021±0.003 (p<0.05 vs BMS, BMS-c), XV: 0.012±0.007 (p<0.05 vs BMS, BMS-c, Res), Silicone tube: 0.010±0.011 (p<0.05 vs BMS, BMS-c, Res). Conclusion: In a model of acute thrombogenicity, Xience V demonstrated the least amount of thrombus in comparison to other second generation DES and BMS. This preclinical thrombogenicity data appears to corroborate the low acute thrombosis rates observed with Xience V in clinical practice.