Blood transfusions during cardiac surgery carry underappreciated risks — from immune sensitization to increased infection susceptibility and longer ICU stays. If a simple iron infusion given before surgery can reduce those transfusions even in patients who are not clinically anaemic, the implications for perioperative care would be substantial and could reshape standard preoperative optimization protocols.
This systematic review and meta-analysis, adhering to PRISMA 2020 standards, pooled data from randomized controlled trials identified across PubMed, Embase, Scopus, Web of Science, and the Cochrane Library through October 2025. The researchers restricted eligibility to adults with baseline hemoglobin meeting WHO criteria for non-anaemia who were scheduled for cardiac surgery. Preoperative intravenous iron was compared against placebo, saline, or standard care. Primary endpoints centered on postoperative red blood cell transfusion incidence and units transfused, while secondary endpoints included postoperative hemoglobin, iron indices, ICU and hospital length of stay, infection rates, all-cause mortality, and adverse events such as hypersensitivity or anaphylaxis. Risk ratios, odds ratios, mean differences, and standardized mean differences with 95% confidence intervals were calculated, and bias was assessed using the Cochrane ROB 2 tool.
The clinical logic here is compelling: even patients with normal hemoglobin can harbor depleted iron stores, and the acute blood loss of cardiopulmonary bypass rapidly unmasks subclinical iron deficiency. Prior meta-analyses focused heavily on anaemic surgical populations; this review targets a broader and arguably undertreated group. That said, the excerpt stops short of reporting pooled effect estimates, which are essential for gauging clinical magnitude. Key limitations to anticipate include heterogeneity in iron formulations, dosing timing, and surgical complexity across included trials. The safety signal around IV iron — particularly cardiovascular events in iron-replete individuals — deserves close scrutiny in this context. If the pooled data confirm meaningful transfusion reduction without disproportionate adverse events, this meta-analysis could offer moderate-certainty evidence supporting routine preoperative iron optimization beyond anaemic thresholds.