Abstract 2567: Late Catch-Up Recovery from Endothelial Vasomotor Dysfunction in Infarct-Related Coronary Artery Treated with Sirolimus-Eluting Stent in Patients with Acute Myocardial Infarction
Myocardial ischemia-reperfusion causes endothelial injury in the infarct-related coronary artery. We have previously shown that sirolimus-eluting stent (SES) implantation can aggravate endothelium-dependent vasomotor dysfunction in infarct-related coronary arteries. This study examined effects of SES implantation on duration of reperfusion-induced endothelial dysfunction in infarct-related coronary arteries. This study enrolled 44 patients with a first acute myocardial infarction (AMI) due to occlusion of the left anterior descending coronary artery (LAD) and successful reperfusion therapy using SESs (n = 22) or bare metal stents (BMS, n = 22). Vasomotor function of LAD in response to acetylcholine (ACh) was repeated 2 weeks, 6 months, and 9 months after AMI. Patients with either residual stenosis or in-stent restenosis in LAD were not included in this study. The vasomotor function was also assessed in 20 control subjects for comparison with that in AMI patients. The SES and BMS groups were similar in terms of AMI-related variables including peak CK levels and 2 week LVEF. At 2 weeks after AMI, SES-treated LAD had greater impairment of epicardial dilation and less blood flow increase in response to ACh than BMS-treated LAD (diameter response; 12% vs. 34% of controls, blood flow response; 23% vs. 76% of controls, at 10 μg/min of ACh, respectively). In BMS-treated LAD, the responses of epicardial diameter and blood flow to ACh had recovered to levels similar to those of controls at 6 months (diameter response; 94% of controls, blood flow response; 92% of controls), and the responses showed no further improvement from 6 to 9 months. In SES-treated LAD, the responses were improved but remained lowered compared with BMS-treated LAD at 6 months (diameter response; 58% of controls, blood flow response; 74% of controls). However, the responses in SES-treated LAD at 9 months showed further improvement to levels near to those of BMS-treated LAD or controls (diameter response; 79% of controls, blood flow response; 88% of controls). Although incomplete, the adverse effects of SES on endothelium-dependent vasomotor function in infarct-related coronary arteries were restored through late catch-up recovery after stent implantation.