Impact of symptom-to-balloon time in patients with non-ST-segment elevation myocardial infarction and complex lesions

Aims Considering the limited data regarding clinical outcomes of patients with non-ST-segment on the ECG elevation myocardial infarction (NSTEMI), this study compared the outcomes of patients undergoing percutaneous coronary intervention with newer-generation drug-eluting stents stratified by the presence/absence of complex lesions and symptom-to-balloon time (SBT; <48 h or ≥48 h). Methods We enrolled 4373 patients with NSTEMI from the Korea Acute Myocardial Infarction Registry-National Institute of Health dataset and stratified them into the complex group (2106 patients; SBT < 48 h, n = 1365; SBT ≥48 h, n = 741) and the noncomplex group (2267 patients; SBT < 48 h, n = 1573; SBT ≥48 h, n = 694). The primary outcome was the 3-year all-cause mortality rate. The secondary outcomes were any major adverse cardiac events (MACE), including cardiac death (CD), recurrent myocardial infarction, and stroke. Results The incidence of all-cause mortality (adjusted hazard ratio, 0.656; P = 0.009), CD ( P = 0.037), and MACE ( P = 0.047) in the complex group and of stroke in the noncomplex group ( P = 0.020) were significantly lower in patients with SBT < 48 h than in those with SBT ≥48 h. Among patients with SBT < 48 h, the stroke incidence ( P = 0.019) was higher in the complex group than in the noncomplex group, while among patients with SBT ≥48 h, the MACE incidence ( P = 0.011) was higher in the former than in the latter. Conclusion SBT reduction effectively decreased the 3-year mortality in patients with NSTEMI in the complex group compared with the noncomplex group.