Abstract 1147: Drug Eluting Stents Do Not Delay Early Endothelialization But Show Distinct Differences In Endothelial Function

Late stent thrombosis and impaired endothelium dependent vasodilation in Cypher and Taxus are often attributed to delayed re-endothelialization. Data to support this hypothesis is scarce and the functional status of endothelium within these drug eluting stents is unknown. We compared 3 DES (Paclitaxel; Sirolimus (-limus via mTOR) and Tacrolimus (-limus via calcineurin)) to BMS in swine coronary arteries with respect to early endothelialization (%EC) at 5 days and function as assessed by immunocytochemistry for eNOS and vWF expression at 28 days (semiquantitative score) and in vitro vasoreactivity at 5 and 28 days. Results. There were no significant differences in %EC between DES and BMS at 5 days (Anova, p=0.7). While vWF expression was similar for all DES, PES showed diminished eNOS expression at 28 days. Microvascular function showed no overt impairment distal to both DES in EC-dependent dilation to bradykinin at 5 and 28 days. However, eNOS blockade by L-NAME uncovered a strongly depressed NO production in both DES at 5 days which recovered at 28 days. Conclusion. DES show no differences in re-endothelialization as compared to BMS. In vitro data showed that both DES induced a temporary reduction in NO production. However, only Paclitaxel showed a prolonged reduction in eNOS expression at 28 days. planimetry of endothelial presence and function