Atrial Thrombosis Prevalence Before Cardioversion or Catheter Ablation of Atrial Fibrillation: An Updated Systematic Review and Meta-Analysis of Direct Oral Anticoagulants Versus Vitamin K Antagonists

: Left atrial or left atrial appendage thrombosis (LAT) is contraindicated for cardiac ablation (CA) or cardioversion (CV) of atrial fibrillation (AF). This study was aimed to compare the frequency of LAT detected by transesophageal echocardiography (TEE) before CA or CV in patients with AF treated with direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs). We searched PubMed, Scopus, Web of Science, and Cochran Library databases from inception through July 13, 2023 to select studies reporting data on LAT identification before CA or CV using TEE in patients with AF treated with DOACs or VKAs. Pooled odds ratios (ORs) with 95% confidence interval were calculated with a random-effects model. Studies retrieved were 50 (38 observational), 29 on CA, 15 on CV, and 6 on both procedures (17,096 patients on DOACs and 13,666 on VKAs). The overall prevalence of LAT was smaller in DOACs than in VKAs, with an OR of 0.66 (0.52 to 0.84), confirmed at sensitivity analysis and in most subgroups. This finding was consistent for the 3 most reported DOACs: the pooled OR for LAT was 0.68 (0.50 to 0.90) in apixaban, 0.67 (0.51 to 0.88) in dabigatran, 0.61 (0.43 to 0.89) in rivaroxaban, and 1.10 (0.74 to 1.64) in edoxaban (not significant). In conclusion, in this large meta-analysis in patients with AF, the prevalence of LAT by TEE evaluation performed before CV or CA appears lower in those treated with DOACs than in those on VKAs. Additional research may help in better understanding differences between these classes of anticoagulant drugs in the setting of protection against AF-related left atrial thrombotic formation.