Treatment Windows and Clinical Outcomes in Late-Presenting Patients with ST-Segment Elevation Myocardial Infarction

Background: Percutaneous coronary intervention (PCI) is the reperfusion strategy typically used in patients with ST-segment elevation myocardial infarction (STEMI) who present with prolonged ischemic symptoms (>12 hours after onset). However, there is no consensus on an optimal time window for PCI. We examined a real-world cohort, assessing time from symptom onset to balloon inflation in relation to long-term nonfatal recurrent myocardial infarction (MI) or all-cause mortality. Materials and Methods: A total of 825 consecutive patients presenting with ischemic symptoms of STEMI >12 hours after symptom onset and undergoing subsequent primary PCI were grouped by time-to-treatment status (<= 7 days or >7 days post-MI). Primary endpoints were nonfatal recurrent MI and all-cause mortality. Results: Cumulative rates of recurrent nonfatal MI at 2 years were 4.1% and 3.3% in patients with symptom-onset-to-balloon inflation times of <= 7 days and >7 days, respectively (P = 0.049); and corresponding mortality rates were 3.4% and 4.7% (P = 0.238). In Cox multivariate analyses, syndrome-onset-to-balloon-inflation time was not independently predictive of recurrent MI (P = 0.052) or mortality (P = 0.651) at 2 years, once adjusted for certain clinical and angiographic variables known to influence patient outcomes. The 2-year rate of recurrent MI was highest in patients with multivessel coronary artery diseases undergoing primary PCI <= 7 days after symptom onset to balloon inflation (P = 0.005). Conclusions: In patients presenting with ischemic signs or symptoms of STEMI >12 hours after initial symptom onset and treated by PCI, symptom-onset-to-balloon-inflation times <= 7 days showed no relation to nonfatal recurrent MI, unless in the presence of multivessel coronary artery diseases.