Perioperative iron – There is no easy answer
Intravenous (IV) iron is a major cornerstone of every PBM programme. It has been shown in many clinical situations that IV iron increases the haemoglobin concentration, decreases the number of RBC transfusions but has no impact on perioperative mortality. However, taking into account this study by Richards and coworkers, it seems as if the tables have turned. They published in the Lancet a high-quality RCT enrolling 487 participants undergoing major abdominal surgery, in which preoperative administration of intravenous iron did not result in a reduction of allogeneic blood transfusions.
Does this mean that we have to rethink the usage of IV iron in the future?
In my opinion, no. The clinical circumstances of this study were rather special. The inclusion criteria included patients with anaemia, but not necessarily iron deficiency anaemia. Although a subgroup analysis revealed that, even in patients with low ferritin and transferrin levels, IV iron was ineffective, it must be stated that there is no single guideline where the administration of iron is recommended when no iron deficiency is present. Furthermore, EPO was not part of the protocol, since this indication (preoperative preparation in major abdominal surgery) is not approved. It has been demonstrated by others that the combination of iron and EPO in orthopaedic and cardiac surgery can be very efficient in increasing perioperative haemoglobin levels and, by that, reducing transfusion needs. One further drawback of the study is that “a blood transfusion was defined as receiving 1 unit (or part thereof) of packed red blood cells or any other blood component.” It is very difficult to imagine how the administration of iron could influence the amount of FFP or platelets given, and therefore the results might be diluted by this rather arbitrary outcome. However, all these shortcomings are discussed in the manuscript and do not render the study useless.
Does the study warrant us to reanalyze our daily clinical strategy?
In my opinion, clearly yes. The results could warrant us to use IV iron only in patients with iron deficiency anaemia. Also, they clearly raise the question whether convincing effects on erythropoiesis can be achieved solely with iron, or whether the full potential of iron can only be revealed in combination with EPO, at least in some clinical indications. This opens the field for several new clinical studies that will help us find the optimal indication for iron and guide the development of useful clinical guidelines. Although recently everything seemed to be known about perioperative iron, there still seems to be room for improvement in our knowledge and in our clinical practice.
– Jens Meier