Red cell distribution width as a predictor of left atrial spontaneous echo contrast in echocardiography

Red cell distribution width (RDW) represents the heterogeneity of red blood cells (anisocytosis). Spontaneous echo contrast (SEC) is thought to be a manifestation of red cell aggregation and it has been linked to the development of thromboemboli. The aim of this study was to evaluate the association between RDW levels and the presence of left atrial SEC (LASEC). One-hundred and 72 patients who underwent transesophageal echocardiography for various indications were enrolled in the study. All patients were categorized into 2 groups according to the presence of LASEC and into 4 groups according to the severity of LASEC. The baseline clinical characteristics, echocardiographic measurements, and laboratory findings, including RDW, were compared between the groups. The RDW (%) level was higher in the LASEC group (14.95 ± 1.32) compared with the non-LASEC group (12.20 ± 1.45; P = 0.0001). When the relationship between RDW and SEC was evaluated according to the increasing grade of SEC, a significant positive correlation was found (r = 0.645, P < 0.0001). In the ROC analysis, an RDW level >13.8% had 70% sensitivity and 89.2% specificity in predicting LASEC (area under the curve = 0.834, P < 0.0001, 95% CI 0.656-0.773). In multivariate analysis, RDW levels >13.8% and the presence of atrial fibrillation were independently associated with LASEC (odds ratio [OR] 1.697; 95% confidence interval [CI] 1.198-2.085; P = 0.001 and OR 1.586; 95% CI 1.195-2.098; P = 0.003, respectively]. Elevated RDW value is associated with the presence and the severity of SEC. RDW may be a useful marker and independent predictor for the presence of SEC.