Evolution of left ventricular thrombus on serial cardiovascular magnetic resonance imaging

AIMS: Current management of left ventricular (LV) thrombus relies on limited, non-contemporary, echocardiography-based studies. Data on LV thrombus evolution and the associated embolic risk are scarce. We aimed to describe the evolution of LV thrombus on serial cardiovascular magnetic resonance imaging (CMR)-the current reference standard for the detection of LV thrombus-and identify correlates of no resolution and the embolic risk associated with resolution status. METHODS AND RESULTS: We conducted a retrospective cohort study of 107 consecutive patients with LV thrombus who had 213 serial CMRs at a median of 255 days after the index CMR. Of these, 97.2% were anticoagulated. At 3 months after detection by CMR, 75% (47/63) had no resolution of LV thrombus; at 6 months, 53% (35/66) had no resolution; and at 12 months, 37% (23/63) had no resolution. Correlates of no resolution at 6 months included a history of myocardial infarction, LV aneurysm, ischaemic aetiology of cardiomyopathy, and larger thrombus volume. Recurrence of LV thrombus was rare at 5.3%. On survival analysis using the landmark analysis method, embolic events often occurred beyond 6 months, more frequently in patients with unresolved LV thrombus. CONCLUSION: Our findings challenge previous literature by demonstrating a lower rate of resolution of LV thrombus and substantial embolic risk beyond 6 months associated with unresolved LV thrombus on serial CMR. Our findings advocate for extended anticoagulation, particularly in patients with markers associated with no resolution. These findings have important implications for clinical practice and research into managing patients with LV thrombus.