ABSTRACT

Animal and imaging study evidence favors early reperfusion for acute myocardial infarction. However, in clinical trials, the effect of symptom-onset-to-balloon (S2B) time on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) has been inconsistent. Moreover, there are few data regarding the ischemic time in China. A total of 3,877 consecutive patients with STEMI with available S2B time undergoing pPCI from January 2013 to September 2014 at 108 hospitals that participated in the China Acute Myocardial Infarction registry were included and stratified into 3 S2B groups: <6 hours, 6 to 12 hours, >12 hours S2B time was tested in multivariate logistic regression analyses as an independent risk factor of mortality (primary outcome), major adverse cardiovascular and cerebrovascular events (MACCE), and impaired myocardial perfusion (secondary outcomes). The median S2B time was 5.5 (3.75 to 8.50) hours. Longer S2B time was associated with higher in-hospital mortality (<6 hours: 2.7%; 6 to 12 hours: 3.4%; >12 hours: 4.9%; p = 0.047) and ST-segment resolution <50% (<6 hours: 16.7%; 6 to 12 hours: 19.2%; >12 hours: 24.3%; p = 0.002) but not MACCE. In multivariate-adjusted analysis, S2B >12 hours remained associated with ST-segment resolution <50% (odds ratio 1.53, 95% confidence interval 1.16 to 2.01, p = 0.002) but not with in-hospital mortality (odds ratio 1.673, 95% confidence interval 0.95 to 2.94, p = 0.073). In conclusion, median S2B time in patients with STEMI undergoing pPCI was longer than that in registry studies from other countries. Longer S2B time was associated with impaired myocardial perfusion but not with in-hospital mortality or MACCE.