Usefulness of apical area index to predict left ventricular thrombus in patients with systolic dysfunction: a novel index from cardiac magnetic resonance

BACKGROUND: LV systolic dysfunction presents an elevated risk of thromboembolism. Previous studies demonstrated low left ventricular ejection fraction (LVEF), ischemic cardiomyopathy and increased myocardial scarring as independent risk factors for LV thrombus formation. Structural changes that alter the size and shape of LV apex may have a significant role in predicting LV thrombus, but there is no definite evidence exists in this entity. METHODS: A case-control cardiac magnetic resonance (CMR) study of 150 patients with LV systolic dysfunction (LVEF < 40%; 30 patients with LV thrombus and 120 patients without thrombus) was performed. Factors associated with thrombus including sphericity index and ‘new’ apical area index (ratio of apical area to entire LV area from a cine four-chamber view) were evaluated. RESULTS: Average age was 63.48 ± 12.82 years and mean LVEF was 29.22 ± 8.53%. Patients with LV thrombus had significantly higher apical area index than those without thrombus (46.5 ± 3.27 vs. 42.71 ± 3.02, p < 0.001) while sphericity index in both groups was not different (1.63 ± 0.27 vs. 1.67 ± 0.19, p = 0.57). Univariate analysis revealed that male gender, prior myocardial infarction, presence of apical aneurysm, ischemic-typed scar, apical scar and apical area index were associated with thrombus. Further, multivariate analysis showed only apical area index and apical scar as independent predictors for thrombus formation. CONCLUSION: Apical area index from CMR is a new index to predict LV thrombus in patients with LV systolic dysfunction and may have a future role in early anticoagulant therapy.