Impact of symptom-to-balloon time on long-term prognosis: a 3-year follow-up study in non-st-segment elevation myocardial infarction patients with complex lesions

Abstract Background Because no data are available, we compared clinical outcomes in patients with non-ST-segment elevation myocardial infarction (NSTEMI), stratified based on the presence of complex lesions, according to symptom-to-balloon time (SBT, <48 h versus ≥48 h), undergoing newer-generation drug-eluting stents. Methods From the KAMIR (Korea Acute Myocardial Infarction Registry)-NIH dataset, a total of 4373 patients diagnosed with NSTEMI were enrolled and stratified into two groups: the complex group (2106 patients; SBT <48 h, 1365; SBT ≥48 h, 741) and the non-complex group (2267 patients, SBT <48 h, 1573; SBT ≥48 h, 694). The primary outcome was the 3-year all-cause death rate, and the secondary outcome was major adverse cardiac events (MACE), including cardiac death (CD), recurrent MI, and any repeat revascularization. Results The rates of all-cause death (adjusted hazard ratio [aHR], 0.656; p = 0.009) and cardiac death (aHR, 0.633; p = 0.037) in the complex group, and the rate of all-cause death (aHR, 0.773; p = 0.036) in the total study population, were significantly lower for patients with SBT <48 h than for those with SBT ≥48 h. In the non-complex group, all clinical outcomes were not significantly different between the SBT <48 h and SBT ≥48 h groups. In the SBT ≥48 h group, the complex group exhibits higher rates of all-cause death, any repeat revascularization, and MACE than those of the non-complex group Conclusions Reducing SBT was more effective in decreasing 3-year mortality in NSTEMI patients with a complex group compared to the non-complex group.