Anemia in heart failure: still an unsolved enigma

Abstract

Background Anemia affects one-third of heart failure patients and is associated with increased morbidity and mortality. Despite being one of the commonest comorbidities associated with heart failure, there is a significant knowledge gap about management of anemia in the setting of heart failure due to conflicting evidence from recent trials. Main body The etiology of anemia in heart failure is multifactorial, with absolute and functional iron deficiency, decreased erythropoietin levels and erythropoietin resistance, inflammatory state and heart failure medications being the important causative factors. Anemia adversely affects the already compromised hemodynamics in heart failure, besides being commonly associated with more comorbidities and more severe disease. Though low hemoglobin levels are associated with poor outcomes, the correction of anemia has not been consistently associated with improved outcomes. Parenteral iron improves the functional capacity in iron deficient heart failure patients, the effects are independent of hemoglobin levels, and also the evidence on hard clinical outcomes is yet to be ascertained. Conclusion Despite all the research, anemia in heart failure remains an enigma. Perhaps, anemia is a marker of severe disease, rather than the cause of poor outcome in these patients. In this review, we discuss the current understanding of anemia in heart failure, its management and the newer therapies being studied.

Impact of anemia on clinical outcomes in patients with acute heart failure: A systematic review and meta‐analysis

“…The associated hemodynamic mechanisms are slower and more complex and produce adverse effects. The reduced number of circulating red blood cells results in a decrease in whole blood viscosity leading to a decrease in systemic peripheral vascular resistance, while low hemoglobin further activates nitric oxide‐mediated vasodilation leading to hypotension, which reflexively stimulates pressure receptors to activate pressor hormones to maintain peripheral tissue perfusion 5,30,34,35 . The heart is chronically overworked, which eventually leads to ventricular hypertrophy and myocardial remodeling.…”

“…DISCUSSIONBased on a large amount of clinical and basic research data, patients with heart failure are more likely to have combined anemia, of which the most important pathophysiological mechanisms are iron deficiency and insufficient erythropoietin synthesis 25. The reasons for the increased incidence of anemia in heart failure patients are related to the following5,[25][26][27][28][29][30] : (1) Inadequate food intake and hypothalamic appetite regulation dysfunction lead to reduced iron intake; (2) irritation of the gastrointestinal mucosa after treatment with antiplatelet and or anticoagulant drugs, resulting in microscopic blood flow loss in the gastrointestinal system. At the same time, edema of the intestinal mucosa in the late stage of heart failure inhibits iron absorption; (3) plasma levels of inflammatory factors such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) are elevated in patients with heart failure.…”

Heart Failure Treatments Such As Angiotensin Receptor/Neprilysin Inhibitor Improve Heart Failure Status and Glucose Metabolism

“…In patients with heart failure, anemia adversely affects the hemodynamics, and parenteral iron replacement therapy was shown to improve subjective symptoms and exercise capacity [19]. A previous report showed that intravenous iron infusion improved abnormal glucose metabolism in patients with type 2 diabetes and iron deficiency [20].…”

A Case Report on an Underappreciated Cause of Heart Failure: Chronic Viral Myocarditis

“…In fact, viral myocarditis is an underdiagnosed cause of acute heart failure and chronic dilated cardiomyopathy. Another commonly missed trigger of acute heart failure in patients with dilated cardiomyopathy is iron deficiency anemia [4].…”