Background No-reflow occurring during percutaneous coronary intervention (PCI) has been associated with poor inhospital outcomes. The objectives of this analysis were to evaluate the occurrence of no-reflow as an independent predictor of adverse events and to determine whether treatment with intracoronary vasodilator therapy affected clinical outcomes.Methods We prospectively collected data from 4264 consecutive patients undergoing PCI, identifying those with no-reflow, and analyzed their treatments and clinical outcomes.Results No-reflow was identified in 135 of 4264 patients (3.2%). Baseline demographics were comparable, but patients with no-reflow were more likely to have acute myocardial infarction, unstable angina, and cardiogenic shock and to have undergone saphenous vein graft interventions. No-reflow was highly predictive of postprocedural myocardial infarction (17.7% vs 3.5% in patients without no-reflow, P < .001) and death (7.4% vs 2.0%, P < .001) and remained a strong independent predictor of death or myocardial infarction after multivariate analysis (odds ratio 3.6, P < .001). The administration of intracoronary verapamil, sodium nitroprusside, or both was not associated with a reduction in the rate of death or myocardial infarction (adjusted odds ratio of death or myocardial infarction 1.04, P = .945 for nitroprusside; and adjusted odds ratio of death or myocardial infarction 0.94, P = .91 for verapamil), despite an improvement in angiographic flow rates for patients treated with sodium nitroprusside.Conclusions No-reflow is a strong independent predictor of inhospital mortality and postprocedural myocardial infarction. Administration of verapamil or sodium nitroprusside was not associated with improved inhospital outcomes in patients with no-reflow, although anterograde flow rates were improved in patients treated with sodium nitroprusside. (Am Heart J 2003;145:42-6.)