Prevalence of Left Atrial Appendage in Patients Anticoagulated with Direct Oral Anticoagulants: Systematic Review and Meta analysis.

Background Multiple studies have examined the prevalence of left atrial appendage thrombus (LAAT) in patients anticoagulated with direct oral anticoagulants (DOACs) and have reported conflicting results. Methods Studies reporting the prevalence of LAAT on transesophageal echocardiography (TEE) after 3 or more weeks of DOAC therapy were identified. The proportions of anticoagulated patients diagnosed with LAAT were pooled using random-effects models. Pre-specified subgroup analyses by the indication of TEE (pre-atrial fibrillation (AF) ablation versus cardioversion) and TEE strategy (routine use versus selective) were conducted via stratification. Results Forty studies were identified: 22 full manuscripts and 18 abstracts. Only 11 studies performed TEE routinely. Most studies included patients with paroxysmal AF and low thromboembolic risk. The pooled prevalence of LAAT was 2.5% [95%CI (1.6% – 3.4%)]. The prevalence of LAAT is lower in the pre-AF ablation group compared with pre-cardioversion (1.1% versus 4.0%, P=0.033). Routine TEE strategy yielded a lower LAAT prevalence in both groups (0.1% versus 2.3%, P=0.002 and 3.2% versus 5.8%, P=0.432; respectively). Conclusion The reported prevalence of LAAT on TEE in patients treated with DOACs is highly variable. Factors associated with high LAAT prevalence were pre-cardioversion indication and selective TEE strategy. Routine use of TEE before AF ablation may not be warranted.