IMPORTANCE OF INFARCT-RELATED ARTERY PATENCY FOR RECOVERY OF LEFT-VENTRICULAR FUNCTION AND LATE SURVIVAL AFTER PRIMARY ANGIOPLASTY FOR ACUTE MYOCARDIAL-INFARCTION

Objectives. The purpose of this study was to evaluate the importance o f late infarct-related artery patency for recovery of left ventricular function and late survival after primary angioplasty for acute myocar dial infarction, Background. Infarct-related artery patency is thought to improve late survival by its effect on preservation of left ventri cular function. Patency may also enhance late survival by preventing l eft ventricular dilation and reducing arrhythmias, independent of myoc ardial salvage. However, most studies have not shown patency to be an independent predictor of survival when late left ventricular function is taken into account. Methods. We followed up 576 hospital survivors of acute myocardial infarction treated with primary angioplasty for 5. 3 years. Ejection fraction and infarct-related artery patency were det ermined at follow-up catheterization at 6 months. Predictors of late c ardiac survival were determined using Cox regression mod els. Results. Patients with patent arteries had more improvement and a better late ejection fraction than patients with occluded arteries (56.3% vs. 47.9 %, p = 0.001). In patients with acute ejection fraction <45%, late sur vival was better in those with patent versus occluded arteries (89% vs . 44%, p = 0.003), but patency was not a significant predictor after i mprovement in ejection fraction was taken into account. In patients wi th a large anterior infarction, patency was a significant independent predictor of late survival. Conclusions. Infarct-related artery patenc y is important for recovery of left ventricular function, and in patie nts with acute ejection fraction <45%, patency is important for late s urvival. Our data are consistent with the hypothesis that the survival benefit is due primarily to the effect of patency on recovery of left ventricular function, In patients,vith a large anterior infarction, p atency appears to provide an additional late survival benefit independ ent of myocardial salvage, These observations support the need for add itional clinical trials of late reperfusion in patients with a large a nterior infarction.