Filling defects in the left atrial appendage restricted to the early phase of cardiac computed tomography as a potential risk of left atrial appendage dysfunction

Abstract

Background: Filling defects within the left atrial appendage (LAA) restricted to the early phase of computed tomography (CT) are not highly specific to the presence of thrombosis. The true significance of LAA early filling defects without thrombus remains uncertain. We evaluated the predictors of LAA early filling defects on echocardiography and cardiac CT findings in patients with atrial fibrillation (AF).

Methods: Cardiac CT findings of 641 patients with AF who underwent transesophageal echocardiography prior to pulmonary vein isolation from 6 January 2013 to 16 December 2019 at our institution were retrospectively analyzed. We investigated potential predictors of LAA early filling defects and computed the receiver operator characteristics, choosing a threshold value at which the likelihood of LAA early filling defects could be predicted.

Results: Early filling defects within the LAA correlated significantly with a history of persistent AF [p = 0.014; odds ratio (OR), 2.36; 95% confidence interval (CI), 1.19-4.66), low left ventricular ejection fraction (p = 0.009; OR, 2.62; 95% CI, 1.28-5.38), diminished LAA flow velocity (p < 0.001; OR, 0.97; 95% CI, 0.96-0.99) below 45.3 cm/s (sensitivity, 63.6%; specificity, 72.4%), and increased indexed LAA volume (p = 0.001; OR, 1.18; 95% CI, 1.07-1.30) ≥7.64 cm3/m2 (sensitivity, 70.5%; specificity, 69.0%).

Conclusion: Early filling defects within the LAA on cardiac CT were associated with LAA function including risk factors for thrombus development, which could lead to noninvasive estimation of LAA function and additional information for risk stratification of thromboembolic events in patients with AF.

Keywords: Atrial fibrillation; Cardiac computed tomography; Early filling defects; Left atrial appendage.