Hematinic and Iron Optimization in Peri-operative Anemia and Iron Deficiency.

Abstract

Preoperative anemia is independently associated with worse postoperative outcomes following cardiac and noncardiac surgery. This article explores the current understanding of perioperative anemia and iron deficiency with reference to definition, diagnosis, and treatment. Iron deficiency is the most common cause of anemia. It can arise from reduced iron intake, poor absorption, or excess iron loss. Inflammation throughout the preoperative period can drive iron sequestration, leading to a functional deficiency of iron and the development of what was referred to until recently as the "anemia of chronic disease." Current best practice guidance supports the routine administration of preoperative intravenous iron to treat anemia despite limited evidence. This "one size fits all" approach has been called into question following results from a recent large, randomized trial (the PREVENTT trial) that assessed the use of a single dose of intravenous iron compared to placebo 10-42 days before major abdominal surgery. Although there were no improvements in patient-centered outcomes apparent during the initial hospital stay, secondary endpoints of this trial suggested there may be some late benefit after discharge from the hospital (8 weeks postoperatively). This trial raises questions on (1) the mechanisms of iron deficiency in the perioperative patient; (2) the need to reassess our opinions on generic anemia management; and (3) the need to address patient outcomes after discharge from hospital. Despite the known associations between preoperative anemia (particularly iron deficiency anemia) and poor postoperative outcome, recent evidence suggests that administering intravenous iron relatively close to surgery does not yield a tangible short-term benefit. This is made more complex by the interplay between iron and innate immunity. Iron deficiency irrespective of hemoglobin concentration may also impact postoperative outcomes. Therefore, further research into associations between iron deficiency and postoperative outcomes, and between postoperative anemia, delayed outcomes (hospital readmission), and the efficacy of postoperative intravenous iron is required.