BackgroundAfter thrombolytic therapy, long-term patency of the infarct-related artery may reduce arrhythmias, limit ventricular dilatation, and provide collaterals to another in-farct zone if further infarction occurs. However, independent long-term prognostic value of infarct artery patency has not been shown.Methods and ResultsWe followed 312 patients with first myocardial infarction treated < 4 hours after pain onset with thrombolysis (streptokinase [n=188] or recombinant tissue-type plasminogen activator [n=124]). At 28±11 days, cardiac catheterization was performed. Flow of the infarct-related artery was assessed by the TIMI scoring system, and a scoring system relating coronary stenoses and flow to the amount of myocardium supplied was also used. Follow-up was for 39 + 13 months. Cardiac death occurred in 5.8% of patients, and there were two noncardiac deaths. Revascularization was performed in 11.5% of patients. On univariate and multivariate analysis, ventricular function (ejection fraction,P= .006 and .02, or end-systolic volume index,P= .01 and .06) was the most important prognostic factor. Patency of the infarct-related artery measured as TIMI 3 flow was marginally significant on univariate analysis (P= .08) but not on multivariate analysis (P= .2). Patency was an independent prognostic factor in univariate and multivariate analysis when measured as an occlusion score (amount of myocardium supplied by an oc-cluded artery,P= .01 and < .05). When the ejection fraction was .50%, only occluded arteries supplying > 25% of the left ventricle affected prognosis adversely. If the ejection fraction was < 50%, occluded arteries supplying < 25% of myocardium also adversely affected prognosis. Treadmill exercise duration 4 weeks after infarction was the only other prognostic factor identified.ConclusionsVentricular function and infarct-related artery patency are independent prognostic factors after thrombolytic therapy for acute myocardial infarction.