Association between Red Cell Distribution Width and Left Atrial Thrombus in Patients with Valvular Atrial Fibrillation

Background: Red cell distribution width (RDW) is a quantitative measure of variability in the size of circulating erythrocytes and previously shown to provide information concerning the prothrombotic status or adverse outcome of cardiovascular disease. Left atrial thrombus (LAT) is commonly detected in patients with valvular atrial fibrillation (VAF) due to rheumatic mitral valve stenosis (RMVS) but there is very limited data regarding the predictive value of RDW for the development of LAT in these patients. Aim: To determine the association between RDW and LAT in VAF patients. Methods: A total of 58 patients were included in a retrospective observational study between January 2016 to December 2016 in patients who admitted to Dr. Moewardi General Hospital, due to symptomatic VAF. Blood examination and transthoracic echocardiography were performed to all patients. LAT was defined as a fixed or mobile echogenic mass within left atrium (LA) and left atrial appendage (LAA). The RDW was compared between a patient with LAT or without LAT. Results: There were 28 patients (mean age: 46.2±13.3 years) in LAT(+) group and 30 patients (mean age: 45.6±11.5 years) in LAT(-) group. RDW was significantly higher in LAT(+) group (14.4±1.8% vs. 13.3±1.5%, p=0.010). The RDW was independent predictor of LAT by multivariate analysis (OR 1.619; p=0.020; 95% CI: 1.079-2.429). The cut-off RDW value for LAT was >13.5% with a sensitivity of 73.3% and a specificity of 64.3% (area under curve=0.700; 95% CI: 0.562-0.838; p=0.009). The prevalence of LAT was significantly higher in patient with an RDW >13.5% than in those with an RDW <13.5 % (64.3% and 35.7%, p=0.002), with prevalence ratio 5.91. Conclusion: This study shows that a higher level of RDW has an association with the presence of LAT and an independent risk factor of LAT formation in patients with VAF.