Left Ventricular Thrombus After Acute Myocardial Infarction

Importance

Left ventricular (LV) thrombus is a complication of acute myocardial infarction (MI) and is associated with systemic thromboembolism. With randomized clinical trials investigating the optimal antithrombotic regimen in patients with MI who require concomitant chronic anticoagulation and with the emergence of the direct-acting oral anticoagulants, treatment options for post-MI LV thrombus have become more complicated. Herein, we review the epidemiology, pathogenesis, diagnosis, prevention, and treatment of LV thrombus after acute MI.

Observations

Contemporary epidemiologic data suggest the incidence of LV thrombus, detected using optimal imaging modalities, may be as high as 15% in patients with ST-segment elevation MI and up to 25% in patients with anterior MI. While a standard transthoracic echocardiogram is commonly used for screening, it is limited by low sensitivity for LV thrombus detection, necessitating the addition of contrast (unless contraindicated) and/or use of cardiac magnetic resonance imaging when pretest probability is high. To our knowledge, there are no existing randomized clinical trials evaluating the safety and efficacy of anticoagulation in the prevention or treatment of LV thrombus after MI, and clinicians must rely on available epidemiologic and trial-generated data from related entities to guide treatment. Randomized clinical trials have confirmed that triple therapy increases bleeding rates compared with less potent antithrombotic regimens after MI, and observational data suggest that triple therapy regimens may not prevent LV thrombus formation. On the other hand, if an LV thrombus is detected, anticoagulation is essential to prevent systemic thromboembolism. We offer 1 approach to treatment, grounded in the best available data.

Conclusions and Relevance

Uncertainties remain regarding the optimal screening pathway, frequency of follow-up imaging, candidate selection for thromboprophylaxis, and treatment strategies for post-MI LV thrombus. Ongoing studies from related therapeutic areas of varying antithrombotic regimens will continue to inform the optimal approach to treatment; however, more dedicated study of this clinical conundrum is also needed.