Left Atrial Appendage Thrombus in Transcatheter Aortic Valve Replacement: Incidence, Clinical Impact, and the Role of Cardiac Computed Tomography.

Objectives: The aim of this study was to describe the incidence and clinical impact of left atrial appendage thrombus (LAAT) in a population referred for transcatheter aortic valve replacement (TAVR) and to examine the role of cardiac computed tomography (CCT) in the diagnosis of LAAT.

Background: Atrial fibrillation is common in patients undergoing TAVR. Embolization of LAAT is a potential mechanism of periprocedural stroke. The incidence and clinical impact of LAAT in a TAVR cohort have not been reported, and the optimal method for diagnosing LAAT remains unclear.

Methods: Dual-phase cardiac computed tomographic scans were examined for the presence of LAAT in 198 consecutive patients referred for consideration of TAVR. Findings on CCT were compared with those on transesophageal echocardiography (TEE) when both modalities were available.

Results: The incidence of LAAT on CCT was 11% in the overall cohort and 32% in patients with atrial fibrillation. Two patients (1.6%) had LAAT on CCT but were not known to have histories of atrial fibrillation. Ninety-eight patients also underwent TEE. Compared with TEE, CCT had sensitivity and specificity of 100% and 98%, respectively, and a negative predictive value of 100%. In the 124 patients who underwent TAVR, the in-hospital stroke rate was 4.8%. The risk for stroke appeared higher in patients with LAAT (20% [2 of 10]) compared with patients without LAAT (3.8% [4 of 105]).

Conclusions: The incidence of LAAT in patients considered for TAVR is high, and LAAT embolization may represent a clinically relevant cause of periprocedural stroke. Dual-phase CCT is an accurate modality for the diagnosis of LAAT. It may obviate the need for pre-procedural TEE. The presence of LAAT should be examined in all patients undergoing TAVR and strategies developed for those patients in whom LAAT is identified.