Prevalence and risk factors of left atrial thrombus in patients with atrial fibrillation and lower class (IIa) recommendation to anticoagulants

Background: Oral anticoagulation therapy (OAT) prevents ischaemic incidents in patients with atrial fibrillation (AF). CHA(2),DS2-VASc risk score >= 2 of points in men and >= 3 in women is a class I indication for OAT. OAT should also be considered as a prevention of thromboembolism in AF men with a CHA(2)DS(2)-VASc score of 1 point and women with 2 points, but the class of recommendation is lower (Ha). This study aims to assess the occurrence of left atrial appendage thrombus (LAAT) and risk factors of its formation in patients with lower class recommendation to oral antiocoagulation treatment. Methods: The study group consisted of 1,858 patients: 555 patients with class IIa indication to OAT (Ha group) and 1,303 patients with class I indication as a control group (I group). Patients were admitted to three cardiology departments. All subjects underwent transoesophageal echocardiography. Results: The incidence of LAAT was comparable in both IIa and I group: LAAT was confirmed in 30 (5.4%) subjects of IIa group and in 77 (5.9%) of I group. The prevalence of LAAT in IIa group was higher on treatment with VKAs (in comparison to NOACs) (8.4% vs. 3.4%, P=0.010), and lower in case of paroxysmal AF (in comparison to non-paroxysmal AF) (2.4% vs. 9.8%, P=0.0002). Multivariate logistic regression revealed the following variables as the independent predictors of LAAT in Ha group: treatment with VKAs (OR 2.99, 95% CI: 1.33-6.69; P=0.007), paroxysmal AF (OR 0.26, 95% CI: 0.11-0.62; P=0.002) and eGFR <60 InUrnin/1.73 m(2) (OR 3.19, 95% CI: 1.42-7.16; P=0.005). Conclusions: The prevalence of LAAT in AF patients with lower class (IIa) recommendation to anticoagulants was comparable to higher (I). Treatment with VKAs, along with non-paroxysmal type of AF and eGFR <60 mL/min/1.72 m(2) were identified as the strongest predictors of LAAT in Ha group.