Abstract
Objective Immediate primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction is closely associated with better clinical outcomes. However, the optimal timing of PCI for the culprit lesion in non-ST-elevation myocardial infarction (NSTEMI) is not fully understood. The aim of this study was to compare clinical outcomes between patients with early and delayed PCI and to investigate whether early PCI within 24 hours of admission can improve long-term clinical outcomes in patients with NSTEMI. Methods This was a single-center, retrospective study. The primary endpoint was major adverse cardiovascular events (MACE), which was defined as the composite of all-cause death, non-fatal MI, and re-admission for heart failure. Results We included 816 patients with NSTEMI and divided them into an early PCI group (n=446) and a delayed PCI group (n=370). The median follow-up period was 856 days. The median age was lower in the early PCI group [73 (65-79) years] than in the delayed PCI group [76 (69-81)] (p<0.001). Shock at admission was more frequently observed in the early PCI group (11.9%) than in the delayed PCI group (3.2%) (p=0.001). The incidence of MACE in the delayed PCI group (40.8%) was higher than that in the early PCI group (28.5%) (p<0.001). However, a multivariate Cox hazard analysis revealed that early PCI was not associated with MACE after controlling for multiple confounding factors (hazard ratio 1.005, 95% confidence interval 0.763-1.322, p=0.973). Conclusion The timing of PCI may not be important in hemodynamically stable patients with NSTEMI, as long as primary PCI is performed.