Marginal anaemia and perioperative transfusion in female patients undergoing cardiac surgery

Females undergoing cardiac surgery frequently require allogeneic blood transfusion, yet sex-specific haemoglobin (Hb) thresholds may underestimate physiological vulnerability in these patients. Recent evidence suggests that Hb values between 12.0 and 12.9 g/dL may represent marginal anaemia with clinically relevant consequences. This study assessed the impact of preoperative Hb on perioperative transfusion in females undergoing elective cardiac surgery. Anaemia categories were defined as follows: World Health Organization (WHO) anaemia (<12 g/dL in females); marginal anaemia (Hb 12.0-12.9 g/dL in females); and patient blood management (PBM)-defined anaemia (<13 g/dL irrespective of sex).

We conducted a retrospective analysis of 1174 cardiac surgery patients, including 399 females. Females were stratified into three groups: Hb ≥13 g/dL, 12-13 g/dL and <12 g/dL. Perioperative outcomes and predictors of packed red blood cell (PRBC) transfusion were evaluated using multivariable logistic regression. Model performance was assessed using receiver operating characteristic (ROC) curve analysis.

Transfusion rates increased stepwise across Hb strata: 57.3% (≥13 g/dL), 69.6% (12.0-12.9 g/dL) and 87.0% (<12 g/dL) (p <0.001). Females with marginal anaemia (12.0-12.9 g/dL) received more PRBC units per patient than both non-anaemic females and males in the same Hb range. In multivariable analysis, marginal anaemia (odds ratio [OR] 2.05; 95% confidence interval [CI]: 1.39-3.03) and overt anaemia (OR 6.33; 95% CI: 4.40-9.97) remained independent predictors of transfusion.

Marginal anaemia in females undergoing cardiac surgery is associated with an increased risk of perioperative transfusion. Females with marginal anaemia had higher transfusion rates than those with Hb ≥13 g/dL, although quantitatively distinct from overt anaemia.