Long-term outcomes of the modest stent expansion strategy for the culprit lesion of acute myocardial infarction.

Slow flow during primary percutaneous coronary intervention (PCI) is a common complication. Our group showed that the stent (or post-balloon) diameter-to-vessel diameter ratio was inversely associated with slow flow phenomenon. We advocated the utility of modest stent expansion strategy, which was defined as the stent (or post-balloon) diameter-to-culprit vessel diameter ratio < 0.71, for prevention of slow flow phenomenon. This study aimed to compare the long-term outcomes in patients with acute myocardial infarction (AMI) between the modest stent expansion strategy and the aggressive stent expansion strategy (the stent diameter-to-culprit vessel diameter ratio ≥ 0.71). We included 584 AMI patients, which were divided 177 patients in the modest stent expansion group and 146 patients in the aggressive stent expansion group. The primary endpoint was major adverse cardiac events (MACE), which was defined as a composite of cardiac death, ischemia driven target vessel revascularization, and stent thrombosis. The slow flow after stent deployment was more frequently observed in the aggressive stent expansion group (24.0%) than in the modest stent expansion group (4.0%) (P < 0.001). The Kaplan-Meier curves revealed that MACE was comparable between the two groups (P = 0.64). The multivariate COX hazard model showed the non-significant association between the modest stent expansion strategy and MACE (vs. aggressive stent expansion: hazard ratio 1.005, 95% confidence interval 0.619-3.242, P = 0.41). In conclusion, the modest stent expansion strategy was not associated with long-term MACE. Therefore, the modest stent expansion strategy may be a good choice for the culprit lesion of AMI.