Real-world incidence and predictors of left atrial thrombus detected in transesophageal echocardiography before atrial fibrillation ablation procedures

BACKGROUND: Transesophageal echocardiography (TEE) is routinely performed before atrial fibrillation (AF) electrotherapy to exclude left atrial thrombus. AIMS: The aim of this study is to assess the real-world prevalence of left atrial appendage thrombus (LAAT) and improve risk stratification to limit the number of unnecessary TEE studies. METHODS: We retrospectively analysed 7357 TEE exams at high-volume hospital to assess LAAT prevalence. Subsequently, we prospectively studied 517 consecutive patients in whom TEE was routinely performed prior to elective AF ablation to assess LAAT and spontaneous echocardiographic contrast (SEC) prevalence. RESULTS: LAAT was detected in only 1.5% (108/7357) of all TEE studies performed for various indications. In elective AF ablation patients, LAAT or dense SEC was found in only 1.6% of cases (8/511). Predictors of LAAT/SEC were: persistent AF over one year (odds ratio [OR], 0.20; 95% confidence interval [CI], 0.05-0.7; P = 0.012), at least moderate valvular heart disease or post-valve repair/replacement status (OR, 0.46; 95% CI, 0.22-0.98; P = 0.044). Conversely, the identified protective factors included: CHA2DS2-VA score <4 points (OR, 2.1; 95% CI, 1.01-4.32; P = 0.046), left atrial volume index <51.5 ml/m2 (OR, 2.9; 95% CI, 1.37-6.14; P = 0.005), N-terminal pro-B-type natriuretic peptide <956.5 pg/ml (OR, 4.2; 95% CI, 1.98-9.12; P <0.001), and left ventricular ejection fraction >40% (OR, 9.5; 95% CI, 4.29-20.86; P <0.001). A point score and nomogram were developed to predict the odds of absence of LAAT/SEC. CONCLUSIONS: Among the patients referred to AF ablation, easily accessible clinical data may improve selection of patients who truly require TEE to exclude LAAT prior to the procedure. Further studies are needed to independently validate the proposed risk assessment model.