Association of increased red blood cell distribution width with adverse cardiorenal outcomes after cardiac surgery

Perioperative risk stratification remains an important and unmet need in adult cardiac surgery. Red blood cell distribution width (RDW) quantifies the variability in red blood cell (RBC) size and has gained recognition as a potential biomarker across a wide range of clinical conditions.¹ RDW is calculated by dividing the standard deviation of RBC volume by the mean corpuscular volume, yielding a normal range of 11% to 15%. Elevated RDW values indicate anisocytosis, which may be reflective of disruptions in RBC production or increased RBC destruction. RDW is increasingly recognized as a marker of conditions associated with inflammation, anemia, and systemic stress, and recent studies highlight its potential role as a prognostic marker in coronary artery disease, atherosclerosis, acute coronary syndrome, heart failure, and congenital heart disease. Given the routine availability and cost-effectiveness of conducting RDW measurements, RDW may be a valuable tool for perioperative risk stratification. We evaluated the association of RDW with cardiorenal outcomes in adults undergoing cardiac surgery who were part of the large, contemporary Transfusion Requirements in Cardiac Surgery (TRICS) III trial.^2,3