Red Cell Distribution Width in Cardiac Diseases: Role of Hemorheology and Chronic Inflammation

Red cell distribution width (RDW) is a simple, inexpensive, and unique laboratory parameter. This hematologic parameter reflecting the heterogeneity of red cell size was used conventionally to differentiate anemic diseases but is used currently as a prognostic marker of common as well as cardiac diseases. Higher RDW is associated with lower therapeutic response in patients with acute myocardial infarction undergoing percutaneous coronary intervention, those with atrial fibrillation undergoing catheter ablation, and those with heart failure under drug therapy. RDW showing such wide usefulness is linked to the chronic inflammation, which dysregulates normal erythropoiesis and impairs deformability of red cells within the microcirculation. Disturbed microcirculation causes persistent and systemic tissue hypoxia-reoxygenation insult impairing redox homeostasis, which induces chronic inflammation and clonal hematopoiesis of intermediate potential as a stress memory. Therefore, higher RDW is sustained in many cardiac diseases by hemorheological insult causing chronic inflammation under the clonal expansion of erythroid cells leading to the reduced deformability and increased RDW of red cells by unknown mechanisms.