Increased RDW has been found to be a marker of adverse outcomes in cardiovascular disease (CVD), although the exact mechanism remains unclear. Recently, several authors have found that higher RDW is associated with decreased erythrocyte deformability, which can impair blood flow through microcirculation, a fact which may explain the increased risk for CVD events associated with elevated RDW. The aim of the present study was to investigate the association between RDW and erythrocyte deformability in patients with acute myocardial infarction (AMI). The study group comprised 60 AMI patients and 72 gender- and age-matched controls, in whom erythrocyte deformability was determined by means of the elongation index (EI) in a Rheodyn SSD, along with haematological, biochemical and inflammatory parameters. Patients showed higher RDW (p = 0.012) and lower EI (p < 0.05) than controls. When anaemic patients were removed from the study, AMI showed still lower EI than controls (p < 0.05), but no differences in RDW were observed (p = 0.141). RDW correlated inversely with haematimetric indices (p < 0.001), but not with inflammatory and biochemical parameters (p > 0.05). EI correlated inversely with Hb, MCHC (p < 0.001) and directly with MCV (p < 0.05). EI also correlated inversely with glucose (p < 0.05) and directly with HDL-cholesterol (p < 0.05). The multivariate regression model showed that only MCV and Hb were independent predictors of RDW (beta coefficients: -0.383, -0.208; p < 0.001, p = 0.050, respectively). In addition, MCV, MCHC and hyperlipidaemia were independent predictors of EI (beta coefficients: 0.366, -0.533, -0.192; p < 0.001, p < 0.001, p = 0.019 respectively). In AMI patients, increased RDW is not related with EI, so this mechanism does not seem to be responsible for an increased CDV risk in these patients.
Keywords: Red blood cell distribution width; acute myocardial infarction; erythrocyte deformability.