Predictors of Left Atrial Thrombi for Subsequent Thromboembolisms: Risk Factors Derived from Echocardiography

Background: Evidence regarding the management of left atrial thrombi (LATs) is limited.

Objectives: We aimed to investigate factors associated with subsequent thromboembolism in patients with LATs and explored potential management approaches.

Methods: This multicenter retrospective study consecutively enrolled patients who underwent morphological assessment of LAT using echocardiography. We evaluated associations between clinical and echocardiographic variables and the occurrence of symptomatic thromboembolism.

Results: 206 patients from 15 centers were enrolled. During follow-up period after echocardiography diagnosis (651 [interquartile range, 174-1,316] days), 19 patients (9.2%) developed thromboembolism. Cox regression analysis identified three independent predictors of thromboembolism: LAT maximum length >20 mm (hazard ratio [HR]: 2.63, 95% confidence interval [CI]: 1.03-6.68, P=0.043), reduced left ventricular ejection fraction (LVEF; ≤40%) (HR 2.95, CI 1.14-7.63, P=0.026), and thrombus mobility (HR 3.40, CI 1.27-9.11, P=0.015). Patients with ≥2 of these factors (n=52) were categorized as the high-risk group, while those with <2 factors (n=154) formed the low-risk group. Patients in the high-risk group had a higher incidence of thromboembolism (23.1% vs. 4.5%, P<0.001), despite a greater proportion undergoing urgent surgical thrombectomy (UST; 17.3% vs. 5.8%, P=0.025) compared to the low-risk group. Among the high-risk patients, UST was associated with a significantly lower rate of adverse outcomes, including all-cause mortality, heart failure hospitalizations, major bleedings, and thromboembolisms, at 90 days (0% vs. 35.6%, log-rank P=0.048).

Conclusions: In patients with LATs, large thrombus size, reduced LVEF, and thrombus mobility were associated with subsequent thromboembolism. UST was associated with fewer adverse clinical outcomes in patients with ≥2 risk factors.