Consideration of non-valvular atrial fibrillation with left atrial appendage thrombus formation despite under appropriate oral anticoagulation therapy

Abstract

Background Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia, with a prevalence of about 2–3% in the general population. In accordance with CHADS2 or CHA2DS2-VASc score, appropriate oral anticoagulation therapy such as warfarin or direct oral anticoagulants (DOAC) significantly reduced the risk of thromboembolic events. However, left atrial (LA) thrombus can be detected in the LA appendage (LAA) in AF patients despite appropriate oral anticoagulation therapy. Purpose Our purpose was to investigate the associated factors of LAA thrombus formation in non-valvular atrial fibrillation (NVAF) patients despite under appropriate oral anticoagulation therapy. Methods We retrospectively studied consecutive 286 NVAF patients for scheduled catheter ablation or electrical cardioversion for AF in our institution between February 2017 and September 2019. Mean age was 67.1±9.4 years, 79 patients (29.5%) were female, and 140 (52.2%) were paroxysmal AF. All patients underwent transthoracic and transesophageal echocardiography before catheter ablation or electrical cardioversion. All patients received appropriate oral anticoagulation therapy including warfarin or DOAC for at least 3 weeks prior to transesophageal echocardiography based on the current guidelines. LAA thrombus was defined as an echodense intracavitary mass distinct from the underlying endocardium and not caused by pectinate muscles by at least three senior echocardiologists. Results Of 286 NVAF patients with under appropriate oral anticoagulation therapy, LAA thrombus was observed in 9 patients (3.3%). Univariate logistic regression analysis showed that age, paroxysmal AF, CHADS2 score ≥3, left ventricular end-diastolic volume index (LVEDVI), left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), LA volume index (LAVI), mitral inflow E and mitral e' annular velocities ratio (E/e'), and LAA flow were associated with LAA thrombus formation. It was noteworthy that multivariate logistic regression analysis showed that LAA flow was independent predictor of LAA thrombus (OR: 0.72, 95% CI: 0.59–0.89, p<0.005) as well as LVEF. Furthermore, receiver operating characteristic (ROC) curve analysis identified the optimal cutoff value of LAA flow for predicting LAA thrombus as ≤15cm/s, with a sensitivity of 88%, specificity of 93%, and area under the curve (AUC) of 0.95. Conclusions LAA flow was strongly associated with LAA thrombus formation even in NVAF patients with appropriate oral anticoagulation therapy. According to our findings, further strengthen of oral anticoagulation therapy or percutaneous transcatheter closure of the LAA may be considered in NVAF patients with appropriate oral anticoagulation therapy but low LAA flow, especially <15cm/s. Funding Acknowledgement Type of funding source: None

A gray zone: Role of transesophageal echocardiography before atrial tachycardia catheter ablation

“…Increased LAVI indicating significant LA enlargement is associated with the presence of thrombus along with well-known risk factors such as age, gender, and type of arrhythmia. 24 Finally, our study suggests that AT may lead to LA stasis, as evidenced by a statistically significant association between AT and SEC. However, we did not find a statistically significant difference between AT and the presence of thrombus in the LA/LAA.…”

“…However, due to the small number of patients, it is not possible to draw definitive conclusions. Increased LAVI indicating significant LA enlargement is associated with the presence of thrombus along with well‐known risk factors such as age, gender, and type of arrhythmia 24 . In this context, in patients planned for catheter ablation for AT, in addition to clinical factors including increased age, female gender, heart failure, and sustained tachycardia, decision‐making regarding the necessity of preprocedural TEE can be made based on LAVI measurements performed during TTE procedures.…”