Objective: Iron supplementation may reduce postoperative anemia, blood transfusions, and infections in patients undergoing surgery. We sought to assess efficacy and safety of prophylactic intravenous iron supplementation in patients without anemia undergoing cardiac surgery.

Methods: In this investigator-initiated industry-sponsored single-center randomized double-blind parallel group trial, we enrolled patients undergoing coronary bypass, aortic or mitral valve or ascending aortic surgery who fulfilled prespecified iron blood test safety criteria. Patients were randomized to receive either a single intravenous 1000 mg dose of ferric carboxymaltose (FCM) or placebo (saline only). Independent unblinded study nurse administered the infusion with masked lines and cannula 2 to 21 days before surgery. Primary efficacy end point was a composite of in-hospital blood transfusions >2 U and nosocomial infection. The trial was registered in Eudract (2017-004901-41).

Results: Altogether 171 patients were screened and 78 randomly assigned to FCM (n = 39) or placebo (n = 39). Trial was prematurely discontinued for futility with regard to reaching the primary end point by the recommendation of the independent data monitoring committee. The primary end point occurred in 3 (7.7%) versus 3 (7.7%) (P = 1.00) of patients assigned to FCM and placebo, respectively, with no difference in blood transfusions >2 U. Fewer hospital readmissions by 3 months follow-up (1 [2.6%] vs 8 [20.5%]; P = .028) were noted in FCM group in a post hoc analysis. Ferritin levels were higher in the FCM group at 3 months indicating more preserved iron stores.

Conclusions: Prophylactic treatment with FCM was safe but did not reduce the need for blood transfusions or postoperative infections at index hospitalization in patients without anemia undergoing cardiac surgery.