Frequency and correlates of early left ventricular thrombus formation following anterior wall acute myocardial infarction treated with primary percutaneous coronary intervention

Abstract

The introduction of primary percutaneous coronary intervention (PPCI) for the treatment of patients with acute ST-segment elevation myocardial infarctions has resulted in a significant decrease in the prevalence of diagnosed left ventricular (LV) thrombus. However, reported rates are still as high as 10% to 20% in patients when followed up to 30 days. The aim of this study was to assess the frequency and predictors of early (<7 days after admission) LV thrombus formation in patients with acute anterior ST-segment elevation myocardial infarctions treated with PPCI. The cohort included 429 consecutive patients with documented acute anterior ST-segment elevation myocardial infarctions, who were treated with PPCI from January 2006 to July 2012. All patients underwent cardiac echocardiography on the first or second day of admission and repeat echocardiography 5 to 7 days after admission. Correlates of LV thrombus were estimated using a logistic multivariate regression model. LV thrombus formations were found in 18 of 429 patients (4%) during hospitalization. The first echocardiographic study diagnosed 11 of 18 LV thrombus formations. Patients with identified LV thrombus had significantly lower LV ejection fractions than those without LV thrombus at admission (p = 0.005) and at discharge (p <0.001). Lower admission LV ejection fractions, Thrombolysis In Myocardial Infarction (TIMI) flow grade ≤1 before angioplasty, and a longer time from symptom onset to PPCI were independent predictors of early LV thrombus formation. In conclusion, late reperfusion, a lower LV ejection fraction, and a lower TIMI score significantly increased the risk for early LV thrombus formations, even in the era of PPCI. Early echocardiographic assessment is warranted when admission test results identify at-risk patients.