Left ventricular thrombus (LVT) is a frequent complication after an acute myocardial infarction (MI) and is associated with systemic thromboembolism. Cardiovascular magnetic resonance imaging (CMR) is the diagnostic gold-standard, but its limited availability makes screening tools necessary. This study sought to identify the clinical and imaging determinants of LVT early and late after an acute MI.

The study grouped the data of 2 observational cohorts of patients with reperfused ST-segment elevation MI patients, including a longitudinal and prospective CMR assessment at baseline, and 3 to 6 months after the inaugural event.

An LVT was found in 51 patients out of the 700 (7.3%) baseline CMR scans, and in 26 out of the 607 (4.3%) at follow-up. LVT patients presented higher rates of anterior infarction, greater infarct size and left ventricular (LV) volumes, and lower LV ejection fraction (LVEF), but similar age, cardiovascular risk factors, and MVO prevalence. At baseline Multivariable analysis showed anterior infarction (OR=5.216 [1.156-23.538] P<0.05) and LV end-systolic volume (LVESV) (OR=1.045 [1.026 - 1.064], P-value <0.001) to be the best correlates among clinical, biological and CMR parameters. At follow-up, LVEF was the best correlate (OR=0.911 [0.867-0.958] P<0.001). At baseline LVESV index lower than 50ml/m² presented a negative predictive value (NPV) of 98.78% [CI: 96.70-99.60] to exclude LVT presence. The specificity to detect an LVT by the use of an LVESV index of 50mL/m² was 50.07% [80.25-97.45]. At follow up LVEF>50% had a NPV of 98.26% [96.06-99.29] and a specificity of 58.44% {54.30-62.47] (Figure 1).

The prevalence of left ventricular thrombus reached 10.6% of STEMI patients. We identified an anterior infarction and greater LV end-systolic volume to be the best determinants of LV thrombus occurrence at baseline, while LVEF was the best predictor at follow-up.