Left atrial thrombosis in patients with atrial fibrillation during uninterrupted oral anticoagulation

Atrial fi brillation (AF) is the most common arrhythmia in adults and requires permanent anticoagulation in the presence of risk factors. Left atrial (LA) thrombus is found in a signifi cant minority of patients despite anticoagulant treatment. We aimed to estimate the prevalence of LA thrombosis on uninterrupted oral anticoagulation (OAC) in AF patients and to determine associated demographic, clinical, echocardiographic and tomographic parameters. Material and methods: We present retrospective study of 702 hospitalizations in 582 patients (397 males, 68.2%) with AF and/or atrial fl utter on uninterrupted OAC for at least 3 weeks, assessed for LA thrombosis with transoesophageal echocardiography and/or cardiac computed tomography. Probability value of p < 0.05 was considered signifi cant for all statistical analyses. Results: The prevalence of LA thrombosis was 6.2%, without signifi cant difference between patients on direct OAC (DOAC) or acenocoumarol (VKA). Non-paroxysmal arrhythmia was signifi cantly associated with LA thrombus, OR 0.369, 95% CI 0.159-0.857, p = 0.02. The proportion of patients on VKA with subtherapeutic INR was signifi cantly higher (30.7%), than the proportion of patients receiving too low dose of DOAC (9.7%), OR 4.1, 95%, CI 2 CI 2.7-6.23, р < 0.001. No association was found between the LA appendage morphology type and the presence of LA thrombus. During a median follow-up of 30 days new stroke/transitory ischemic attack (TIA)/systemic embolism (SE) was registered in seven patients (1.34%), none of them with LA thrombus. Conclusion: The prevalence of LA thrombosis in the studied cohort is comparable to the published data and seemingly had no association with the OAC type. The incidence of stroke/TIA/SE was low on uninterrupted oral anticoagulation during short-term follow-up and there was no association between the presence of LA thrombus and thromboembolic event on follow-up.