Resolution of left ventricular thrombus assessed by echocardiography: insights from a contemporary multicentre prospective registry

Background: How to detect and monitor left ventricular thrombus (LVT) remains complex since clinicians can rely only on retrospective, single-center data. Objectives: To characterize the incidence and independent associates of LVT resolution (assessed with echocardiography) and its clinical implications on long-term follow-up in a contemporary cohort of consecutive patients with LVT. Methods: Ten centers were involved in this observational prospective multicenter study. The use of different antithrombotic regimens and ultrasound contrast was left at the discretion of attending physicians. Echocardiographic follow-up was performed on days 16±8, 48±13, and 132±99 days from LVT detection. Resolution was defined as a complete disappearance of LVT on all echocardiographic views at the last available follow-up. Clinical endpoints included all-cause mortality, embolic complications, and bleeding events. Results: From October 2020 to September 2022, 154 consecutive patients with LVT (mean age 67±11 years, 79% men) were enrolled. Different anticoagulant regimens were used, and the median duration of anticoagulation was 6 (3-12) months. LVT resolution was achieved in 68% at a median follow-up of 36 (IQR15-74) days. At baseline assessment, LVT characteristics like smaller LVT area and mobile LVT were independent predictors of LVT resolution. At follow-up echocardiogram, greater LV global and apical mechanical function were independently associated with LVT resolution (OR, 1.04, 95%CI 1.01-1.07, p=0.026 for LVEF and 0.94, 95%CI 0.89-0.99, p=0.025 for apical wall motion score index). During a median follow-up of 1.91 (IQR, 1.32-2.83) years, patients with LVT resolution showed a significantly lower risk of embolic events (adjusted HR, 0.36 95%CI 0.13-0.99, p=0.04) and death (adjusted HR, 0.36 95%CI 0.14-0.95, p=0.03) compared with those without resolution. Moreover, LVT resolution was not associated with bleeding complications. Conclusions: The present longitudinal multicenter registry reveals that LVT persists in nearly one-third of patients after initial detection, even with anticoagulation therapy, and is associated with a poorer prognosis. Additionally, it offers valuable insights into echocardiographic predictors of LVT persistence, which could inform personalized follow-up strategies and treatment approaches.