A Clinical Trial Assessing the Efficacy of Intravenous Iron for the Treatment of Anemia Following Cardiac Surgery

BACKGROUND Anemia and iron deficiency are highly prevalent in cardiac surgery patients. Both conditions may adversely affect postoperative rehabilitation.

At hospital discharge, anemia is almost invariably present due to perioperative blood loss and frequent blood sampling. Two previous analyses demonstrated a prevalence of anemia early after coronary artery bypass grafting (CABG) of 94% and 98%, respectively. Almost half of CABG patients had persistent anemia two months after surgery. Postoperative anemia may result in debilitating symptoms, like dyspnoea, fatigue and poor exercise tolerance, and is associated with an increased likelihood of cardiovascular events and death after cardiac surgery.

Mild to moderate anemia is commonly corrected with oral iron supplements. Oral iron is however poorly absorbed in patients with chronic diseases, and about 40% of patients suffer from debilitating gastrointestinal side-effects. As iron stores are frequently reduced or depleted after cardiac surgery, treatment with oral iron supplements may take several months.

In patients with chronic heart failure (CHF), iron deficiency is associated with reduced exercise capacity, quality of life and survival even in the absence of anemia. Several large randomised trials demonstrated that treatment with intravenous iron improved clinical symptoms, exercise capacity and quality of life of CHF patients.

RATIONALE It is desirable to replenish body iron stores rapidly after cardiac surgery with the aim to effectively correct anemia, optimize exercise tolerance and improve patient wellbeing.

Modern intravenous iron formulations permit fast replenishment of body iron stores and have emerged as potential alternatives to oral iron. These formulations are well-tolerated and have become an established therapeutic option in anemic patients with reduced intestinal iron absorption. Several studies have demonstrated the efficacy of intravenous iron for the treatment of anemia following major non-cardiac surgery.

Data regarding the efficacy of intravenous iron in cardiac surgery, however, are conflicting.

HYPOTHESIS Single-dose intravenous iron therapy with ferric derisomaltose/iron isomaltoside is superior to oral iron supplementation for the correction of anemia following cardiac surgery. Moreover, single-dose intravenous iron therapy with ferric derisomaltose/iron isomaltoside results in a greater postoperative exercise capacity, an improved quality of life and less fatigue.