The impact of anaemia and intravenous iron replacement therapy on outcomes in cardiac surgery

Anaemia is common in patients with cardiac disease and also in those undergoing cardiac surgery. There is increasing evidence that preoperative anaemia is associated with increased patient morbidity and mortality following surgery. We performed a systematic literature review to assess the impact of anaemia and intravenous (IV) iron supplementation on outcomes in cardiac surgery. Sixteen studies examined preoperative anaemia in detail. One study examined the role of preoperative IV iron administration and a further three, the effect of postoperative iron supplementation on haemoglobin (Hb) levels and the need for transfusion. Preoperative anaemia was associated with higher mortality, more postoperative blood transfusions, longer intensive care unit (ICU) and total hospital stay and also a greater incidence of postoperative cardiovascular events. In the single study that examined preoperative IV iron in combination with erythropoietin treatment, there was decreased blood transfusion, shorter hospital stay and an increase in patient survival. However, this was a small retrospective cohort study, with the observation and treatment groups analysed over different time periods. Postoperative administration of IV iron therapy, either alone or in combination with erythropoietin, was not effective in raising Hb levels or reducing red cell concentrate transfusion. On the basis of currently available evidence, the effect of perioperative administration of IV iron to cardiac surgery patients, alone or in combination with erythropoietin, remains unproven. Well-designed and appropriately powered prospective randomized controlled trials are needed to evaluate perioperative iron supplementation in the context of cardiac surgery.