Pre-percutaneous coronary intervention (PCI) Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow has been identified as a predictor of final TIMI grade 3 flow and better survival. Yet pharmacologic strategies increasing the rates of pre-PCI TIMI grade 3 flow resulted in more bleeding, without a benefit in survival. The aim of this study was to identify the predictors and implications of spontaneous reperfusion before primary PCI in patients with ST-segment elevation myocardial infarction. The Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) and Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trials were combined, and the predictors of core laboratory-determined baseline TIMI grade 3 flow and 1-year outcomes were analyzed according to baseline TIMI flow. Baseline TIMI grade 3 flow was present in 932 of 5,332 patients (17.5%). The independent predictors of baseline TIMI grade 3 flow were diabetes, longer delay to PCI, smoking, and more extensive coronary disease. Patients with compared to those without baseline TIMI grade 3 flow had significantly higher rates of post-PCI TIMI grade 3 flow (99.1% vs 91.4%, p <0.0001) and lower 1-year all-cause mortality (2.7% vs 4.3%, p = 0.02). By multivariate analysis, baseline TIMI grade 3 flow (hazard ratio 1.65, 95% confidence interval 1.01 to 2.71, p = 0.046) and final TIMI grade 3 flow (hazard ratio 3.67, 95% confidence interval 2.45 to 5.48, p <0.001) were significant independent predictors of 1-year survival. In conclusion, TIMI grade 3 flow is present in about 1 in every 6 patients before PCI and paradoxically is more common in patients with higher risk characteristics. TIMI grade 3 flow before as well as after PCI is an independent predictor of greater 1-year survival. These data should inform future trials of ST-segment elevation myocardial infarction with respect to improvement in outcomes.
Copyright © 2011 Elsevier Inc. All rights reserved.