Benefit of Four-Dimensional Computed Tomography Derived Ejection Fraction of the Left Atrial Appendage to Predict Thromboembolic Risk in the Patients with Valvular Heart Disease.

Background And Objectives: Decreased left atrial appendage (LAA) emptying velocity in transesophageal echocardiography (TEE) is related with higher incidence of thrombus and increased risk of stroke. Patients with valve disease are at higher risk of thrombus formation before and after surgery. The aim of this study was to investigate the role of 4-dimensional cardiac computed tomography (4DCT) to predict the risk of thrombus formation.

Methods: Between March 2010 to March 2015, total of 62 patients (mean 60±15 years old, male: 53.2%) who underwent 4DCT and TEE for cardiac valve evaluation before surgery were retrospectively included in the current study. Fractional area change in TEE view and emptying velocity at left atrial appendage in TEE view (Ve) were measured. Ejection fraction (EF) of left atrial appendage in computed tomography (EF) was calculated by 4DCT with full volume analysis. The best cut-off value of EF predicting presence of spontaneous echo contrast (SEC) or thrombus was evaluated, and correlation between the parameters were also estimated.

Results: SEC or thrombus was observed in 45.2%. EF and Ve were significantly correlated (r=0.452, p<0.001). However, fractional area change measured by TEE showed no correlation with Ve (r=0.085, p=0.512). EF <37.5% best predicted SEC or thrombus in the patients with valve disease who underwent 4DCT and TEE (area under the curve, 0.654; p=0.038).

Conclusions: In the patients who underwent 4DCT for cardiac valve evaluation before surgery, EF by volume analysis might have additional role to evaluate LAA function and estimate the risk of thrombus.