Iron and heart failure

Iron deficiency has become a new target to improve functional outcomes in patients with heart failure, and intravenous preparations seem to be the only effective treatment for that purpose. However, the relation among iron and oxygen in this population is far from understood as hepcidin is generally upregulated, potentially avoiding iron availability and harm in the context of excess oxidative stress. Laboratory markers used to detect tissue iron deficiency are highly dependent on needs for hemoglobin synthesis, so that reaching peak hemoglobin for each individual should rationally be the first goal of any attempt with therapeutic iron. A subset of patients receiving intravenous iron may have a worse outcome related to admissions and mortality compared to placebo, suggesting that the laboratory thresholds used to detect iron deficiency in heart failure are highly sensitive but less specific to identify patients that would not benefit of this therapy. A gradual delivery of iron over time with parallel measurement of its uptake for hemoglobin synthesis could therefore be recommended to fulfill tissue needs. Standard oral iron therapy should not be dismissed in heart failure patients with anemia and depleted iron stores (ferritin <30 ng/ml) as, contrary to intravenous iron trials, these patients were not included in a trial resulting in neglectable effect of oral iron on exercise capacity.