Prognostic value of minimal blood flow restoration in patients with acute myocardial infarction after reperfusion therapy

Purpose: The prognostic impact of low-flow reperfusion after percutaneous coronary intervention (PCI) in patients with ST-segment elevation acute myocardial infarction (STEMI) is unknown. The aim of the study was to investigate the impact of low-flow reperfusion after PCI in patients with STEMI. Methods: This study included 1,761 patients with STEMI with a baseline thrombolysis in myocardial infarction (TIMI) flow grade 0 and no collateral circulation to the infarcted region before primary PCI. The primary outcome was 1-year mortality. Results: At the end of PCI procedure there were 115 patients with post-PCI TIMI flow grade 0; 57 patients with TIMI flow grade 1; 218 patients with TIMI flow grade 2; and 1,371 patients with TIMI flow grade 3. At 1 year there were 36 deaths in patients with TIMI grade 0; 28 deaths in patients with TIMI grade 1; 42 deaths in patients with TIMI grade 2; and 162 deaths in patients with TIMI grade 3 [estimates of mortality 32.6, 49.1, 19.6 and 12.1%, respectively; odds ratio (OR) = 1.76, 95% CI 1.08-2.86, P = 0.02, for TIMI flow grade 1 vs. TIMI flow grade 0]. The Cox proportional hazards model identified post-PCI TIMI flow grade as an independent predictor of 1-year mortality [hazard ratio (HR) = 1.99, 95% CI 1.17-3.28; P = 0.01 for TIMI flow grade 1 vs. TIMI flow grade 0]. Conclusions: Patients with STEMI with totally occluded infarct-related arteries and no collateral blood flow to the infarcted region show a greater mortality with post-PCI TIMI flow grade 1 than TIMI flow grade 0.