Influence of thrombolytic therapy on the incidence of left ventricular thrombi after acute anterior myocardial infarction: Role of successful reperfusion

Background: Previous studies have reported controversial results regarding the effectiveness of systemic thrombolysis in preventing left ventricular ( LV) thrombus after acute myocardial infarction (MI). Hypothesis: This study was performed to evaluate the influences of thrombol ysis, and particularly successful reperfusion, on the incidence of LV throm bus formation after acute anterior MI. Methods: In all, 191 patients suffering from a first attack of acute anteri or MI were prospectively evaluated by two-dimensional echocardiography and coronary angiography, performed at the end of the first week and within the first two weeks of MI, respectively. Of these, 98 who presented within 12 h of onset of symptoms received intravenous streptokinase (1.5 million IU), while the remaining 93 patients who, either because of contraindications o r late admission, did not receive thrombolytic treatment served as control group. All patients received aspirin and full-dose anticoagulation with int ravenous heparin. Successful reperfusion in the streptokinase group was ass essed by enzymatic and electrocardiographic evidence. Results: The overall incidence of LV thrombi was 24.6% (47/191). When all p atients were evaluated, no statistically significant difference was found b etween the frequency of LV thrombi in the patients who had thrombolysis (22 .4%) and those who did not (26.8%), despite a trend toward the formation of fewer thrombi in the initial group (p > 0.05). However, the patients who h ad successful reperfusion with streptokinase (n = 64) had significantly red uced incidence of LV thrombi compared with those who did not receive thromb olytic therapy (20 vs. 26.8%, p < 0.05). Stepwise multivariate analysis sug gested that LV abnormal wall motion score (p = 0.01) and presence of LV ane urysm were independent predictors of LV thrombus formation in patients with acute anterior MI. Conclusion: Not all patients who received streptokinase for acute anterior MI, but only those with successful reperfusion had reduced incidence of LV thrombi. The favorable effects of thrombolysis on LV thrombus formation are probably due to the preservation of global LV systolic function.