Intravenous iron supplement for iron deficiency in patients with severe aortic stenosis scheduled for TAVI Results of the IIISAS randomised trial

Pharmacotherapy for Reducing RBC Transfusion for Patients in the ICU: A Systematic Review and Network Meta-Analysis

OBJECTIVES

To determine optional therapeutic strategies by comparing monotherapies and combination therapies to reduce RBC transfusion requirement for patients in the ICU.

DATA SOURCES

MEDLINE, CENTRAL, and Embase were searched for studies published from database inception until July 2023.

DATA EXTRACTION

We included randomized controlled trials comparing erythropoiesis-stimulating agents (Epo), iron, combination therapy with iron and Epo, hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI), vitamin D 3 (VD3), and placebo/no treatment. A frequentist network meta-analysis (NMA) was performed using a random effects model, and the confidence in NMA was rated.

DATA SYNTHESIS

Of 117 eligible studies, 75 studies (15,091 patients) were included in the quantitative analysis. Compared with placebo/no treatment, the combination therapy reduces the requirement for RBC transfusion (risk ratio [RR]: 0.60; 95% CI, 0.49-0.74; confidence rating: moderate). The Epo or iron monotherapy may reduce the requirement for RBC transfusion (RR: 0.81; 95% CI, 0.63-1.04; confidence rating: low; RR: 0.83; 95% CI, 0.70-0.98; confidence rating: low, respectively). Combination therapy may not increase the prevalence of both venous thromboembolism (VTE) (RR: 0.73; 95% CI, 0.25-2.08; confidence rating: low) and infection. Epo monotherapy may not increase the prevalence of VTE but may increase that of infections (RR: 1.27; 95% CI, 0.94-1.73; confidence rating: low). Iron monotherapy may not increase the prevalence of both VTE and infection. Evidence for VD3 and HIF-PHI remains uncertain.

CONCLUSIONS

Combination therapy with iron and Epo likely reduces the requirement for RBC transfusion and may be less harmful than other therapies.

Iron deficiency and cardiovascular disease

Iron deficiency (ID) is common in patients with cardiovascular disease. Up to 60% of patients with coronary artery disease, and an even higher proportion of those with heart failure (HF) or pulmonary hypertension have ID; the evidence for cerebrovascular disease, aortic stenosis and atrial fibrillation is less robust. The prevalence of ID increases with the severity of cardiac and renal dysfunction and is probably more common amongst women. Insufficient dietary iron, reduced iron absorption due to increases in hepcidin secondary to the low-grade inflammation associated with atherosclerosis and congestion or reduced gastric acidity, and increased blood loss due to anti-thrombotic therapy or gastro-intestinal or renal disease may all cause ID. For older people in the general population and patients with HF with reduced ejection fraction (HFrEF), both anaemia and ID are associated with a poor prognosis; each may confer independent risk. There is growing evidence that ID is an important therapeutic target for patients with HFrEF, even if they do not have anaemia. Whether this is also true for other HF phenotypes or patients with cardiovascular disease in general is currently unknown. Randomized trials showed that intravenous ferric carboxymaltose improved symptoms, health-related quality of life and exercise capacity and reduced hospitalizations for worsening HF in patients with HFrEF and mildly reduced ejection fraction (<50%). Since ID is easy to treat and is effective for patients with HFrEF, such patients should be investigated for possible ID. This recommendation may extend to other populations in the light of evidence from future trials.

Iron deficiency in cardiac surgical patients

Iron is an essential element and involved in a variety of metabolic processes including oxygen transport, cellular energy production, energy metabolism of heart muscles, brain function, cell growth and cell differentiation. Preoperative anaemia is an independent risk factor for poor outcome. Recently, iron deficiency was considered only in the context of anaemia. However, negative consequences of iron deficiency in the absence of anaemia have been described for patients undergoing cardiac surgery. To date, the benefit of intravenous iron supplementation in these patients has been controversially debated. In this review, we discuss the latest progress in studies of intravenous iron supplementation in iron deficient cardiac surgical patients.