LONG-TERM PROGNOSTIC IMPORTANCE OF PATENCY OF THE INFARCT-RELATED CORONARY-ARTERY AFTER THROMBOLYTIC THERAPY FOR ACUTE MYOCARDIAL-INFARCTION

Background After thrombolytic therapy, long-term patency of the infarct-related artery may reduce arrhythmias, limit ventricular dilatation, and provide collaterals to another infarct zone if further infarction occurs. However, independent long-term prognostic value of infarct artery patency has not been shown. Methods and Results We 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 how 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=.O8) 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 occluded artery, P=.01 and <.05). When the ejection fraction was greater than or equal to 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. Conclusions Ventricular function and infarct-related artery patency are independent prognostic factors after thrombolytic therapy for acute myocardial infarction.