Red Blood Cell Distribution Width in Heart Failure: Pathophysiology, Prognostic Role, Controversies and Dilemmas

Abstract

Red blood cell distribution width (RDW), an integral parameter of the complete blood count (CBC), has been traditionally used for the classification of several types of anemia. However, over the last decade RDW has been associated with outcome in patients with several cardiovascular diseases including heart failure. The role of RDW in acute, chronic and advanced heart failure is the focus of the present work. Several pathophysiological mechanisms of RDW’s increase in heart failure have been proposed (i.e., inflammation, oxidative stress, adrenergic stimulation, undernutrition, ineffective erythropoiesis, reduced iron mobilization, etc.); however, the exact mechanism remains unknown. Although high RDW values at admission and discharge have been associated with adverse prognosis in hospitalized heart failure patients, the prognostic role of in-hospital RDW changes (ΔRDW) remains debatable. RDW has been incorporated in recent heart failure prognostic models. Utilizing RDW as a treatment target in heart failure may be a promising area of research.

Prognostic value of RDW alone and in combination with NT‐proBNP in patients with heart failure

“…This may reduce peripheral and myocardial tissue oxygenation, and contribute to HF. 24 On the other hand, HF itself may impact RDW. HF involves activation of inflammatory pathways.…”

“… 25 Also, inflammation may impair bone marrow function resulting in release of premature erythrocytes into circulation and increased RDW. 24 , 26 Impaired iron metabolism, which elevates RDW, is also common in HF and contributes to increased hospitalizations. 27 , 28 Vitamin D influences RDW by increasing iron availability and down‐regulating proinflammatory cytokines and hepcidin.…”

“…ANS dysregulation, a contributor to HF progression, may also lead to increased RDW. 24 It is apparent that increased RDW may reflect multiple pathological processes that culminate in HF progression. Summarily, RDW serves as a widely available and cheap way to integrate complex interactions into a single, well validated prognostic biomarker.…”

“…With high anisocytosis, erythrocyte deformability and oxygen‐carrying capacity decrease. This may reduce peripheral and myocardial tissue oxygenation, and contribute to HF 24 . On the other hand, HF itself may impact RDW.…”

“…Inflammatory markers including tumor necrosis factor‐α and interleukin‐6 are increased and may negatively impact prognosis 25 . Also, inflammation may impair bone marrow function resulting in release of premature erythrocytes into circulation and increased RDW 24,26 . Impaired iron metabolism, which elevates RDW, is also common in HF and contributes to increased hospitalizations 27,28 .…”