Long-term Implications of Reocclusion on Left Ventricular Size and Function After Successful Thrombolysis for First Anterior Myocardial Infarction

Abstract

Background Successful thrombolysis can prevent left ventricular dilatation after acute myocardial infarction. However, in almost 30% of patients, reocclusion occurs. The aim of this study was to assess the long-term implications of reocclusion on left ventricular size and function. Methods and Results Fifty-six patients were studied with two-dimensional echocardiography at baseline (2±1.6 days) and 5.0±1.4 years after first anterior myocardial infarction. All patients (a subset of those enrolled in the APRICOT trial) had a patent infarct-related artery when studied <48 hours after thrombolysis and underwent repeat coronary angiography at 3 months. Baseline characteristics were comparable in patients with (n=17) and without reocclusion (n=39). Left ventricular volume indexes were stable in patients without reocclusion. Patients with reocclusion, however, showed a significant increase in end-diastolic volume index (EDVI; P =.008) and end-systolic volume index (ESVI; P =.039). Furthermore, patients without reocclusion demonstrated improvement in wall motion score index (WMSI; P =.0001) and ejection fraction (EF; P =.016), whereas patients with reocclusion did not. After 5 years, patients with reocclusion had significantly larger volume indexes (EDVI, 99±41 versus 76±22 mL/m 2 , P =.007; ESVI, 59±40 versus 39±20 mL/m 2 , P =.017) and more compromised left ventricular function (WMSI, 1.63±0.33 versus 1.39±0.32, P =.013; EF, 45±13% versus 51±11%, P =.077) than patients without reocclusion. Multivariate analysis identified baseline WMSI and reocclusion as significant independent predictors of left ventricular dilatation. Conclusions Reocclusion of the infarct-related artery within 3 months of successful thrombolysis is associated with left ventricular dilatation and is detrimental to functional recovery of left ventricular function 5 years after first anterior myocardial infarction.