Intravenous iron infusion in patients with heart failure: a systematic review and study-level meta-analysis

Editors' highlight picks from 2023 in ESC heart failure

Heart failure is a devastating syndrome affecting an increasingly high number of patients worldwide. Its aetiology and pathogenesis are complex with the involvement of factors ranging from the genetic material through valvular dysfunctions to numerous organs beyond the entire cardiovascular system. Based on continuous efforts of the heart failure scientific community we have witnessed major advances in many related disciplines during the last year. For example, epidemiological aspects-paving the road for improved risk prevention-have been thoroughly analysed for various geographical regions. Additionally, evidence-based approaches now allow the introduction of novel guideline recommended medical therapies (i.e. sodium-glucose transporter 2 inhibitors, and iron supplementation) while basic and translational research aim to explore additional molecular targets for future heart failure diagnostics and medications. All above aspects are addressed in this article, where a selection of articles published in the ESC Heart Failure journal in 2023 are highlighted. The editors are confident that the scientific contributions of ESC Heart Failure effectively served a highly relevant area of cardiovascular research last year.

2024 update in heart failure

In the last years, major progress has occurred in heart failure (HF) management. The 2023 ESC focused update of the 2021 HF guidelines introduced new key recommendations based on the results of the last years of science. First, two drugs, sodium-glucose co-transporter-2 (SGLT2) inhibitors and finerenone, a novel nonsteroidal, selective mineralocorticoid receptor antagonist (MRA), are recommended for the prevention of HF in patients with diabetic chronic kidney disease (CKD). Second, SGLT2 inhibitors are now recommended for the treatment of HF across the entire left ventricular ejection fraction spectrum. The benefits of quadruple therapy in patients with HF with reduced ejection fraction (HFrEF) are well established. Its rapid and early up-titration along with a close follow-up with frequent clinical and laboratory re-assessment after an episode of acute HF (the so-called 'high-intensity care' strategy) was associated with better outcomes in the STRONG-HF trial. Patients experiencing an episode of worsening HF might require a fifth drug, vericiguat. In the STEP-HFpEF-DM and STEP-HFpEF trials, semaglutide 2.4 mg once weekly administered for 1 year decreased body weight and significantly improved quality of life and the 6 min walk distance in obese patients with HF with preserved ejection fraction (HFpEF) with or without a history of diabetes. Further data on safety and efficacy, including also hard endpoints, are needed to support the addition of acetazolamide or hydrochlorothiazide to a standard diuretic regimen in patients hospitalized due to acute HF. In the meantime, PUSH-AHF supported the use of natriuresis-guided diuretic therapy. Further options and most recent evidence for the treatment of HF, including specific drugs for cardiomyopathies (i.e., mavacamten in hypertrophic cardiomyopathy and tafamidis in transthyretin cardiac amyloidosis), device therapies, cardiac contractility modulation and percutaneous treatment of valvulopathies, with the recent finding from the TRILUMINATE Pivotal trial, are also reviewed in this article.

Expert recommendations for the management of iron deficiency in patients with heart failure in Asia

BACKGROUND

Iron deficiency is a common comorbidity in heart failure (HF) and is independently associated with a worse quality-of-life and exercise capacity, as well as increased risk of hospitalization, regardless of anemia status. Although international guidelines have provided recommendations for the management of iron deficiency in patients with HF, guidelines in Asia are less established, and practical use of guidelines for management of iron deficiency is limited in the region.

METHODS

A panel comprising cardiologists from China, Hong Kong, India, Japan, Malaysia, Pakistan, Philippines, Singapore, South Korea, Taiwan, and Thailand convened to share insights and provide guidance for the optimal management of iron deficiency in patients with HF, tailored for the Asian community.

RESULTS

Expert opinions were provided for the screening, diagnosis, treatment and monitoring of iron deficiency in patients with HF. It was recommended that all patients with HF with reduced ejection fraction should be screened for iron deficiency, and iron-deficient patients should be treated with intravenous iron. Monitoring of iron levels in patients with HF should be carried out once or twice yearly. Barriers to the management of iron deficiency in patients with HF in the region include low awareness of iron deficiency amongst general physicians, lack of reimbursement for screening and treatment, and lack of proper facilities for administration of intravenous iron.

CONCLUSIONS

These recommendations provide a structured approach to the management of iron deficiency in patients with HF in Asia.

Latest pharmaceutical approaches across the spectrum of heart failure

Despite major advances in prevention and medical therapy, heart failure (HF) remains associated with high morbidity and mortality, especially in older and frailer patients. Therefore, a complete, guideline-based treatment is essential, even in HF patients with conditions traditionally associated with a problematic initiation and escalation of the medical HF therapy, such as chronic kidney disease and arterial hypotension, as the potential adverse effects are overcome by the overall decrease of the absolute risk. Furthermore, since the latest data suggest that the benefit of a combined medical therapy (MRA, ARNI, SGLT2i, beta-blocker) may extend up to a LVEF of 65%, further trials on these subgroups of patients (HFmrEF, HFpEF) are needed to re-evaluate the guideline-directed medical therapy across the HF spectrum. In particular, the use of SGLT2i was recently extended to HFpEF patients, as evidenced by the DELIVER and EMPEROR-preserved trials. Moreover, the indication for other conservative treatments in HF patients, such as the intravenous iron supplementation, was accordingly strengthened in the latest guidelines. Finally, the possible implementation of newer substances, such as finerenone, in guideline-directed medical practice for HF is anticipated with great interest.

Efficacy of Intravenous Iron in Patients with Heart Failure with Reduced Ejection Fraction and Iron Deficiency: A Systematic Review and Meta-Analysis of Randomized Control Trials

BACKGROUND

The European Society of Cardiology (ESC) provided a focused update to the 2021 Guideline for the Management of Heart Failure, now providing a 1A recommendation for intravenous iron in patients with heart failure with reduced ejection fraction (HFrEF) and iron deficiency (ID). However, the findings from randomized controlled trials (RCT) are mixed. This systematic review of RCTs aims to provide an update and synthesize the evidence addressing the association of intravenous iron with patient-based outcomes in patients with HFrEF and ID.

METHODS

Any RCT evaluating the effect of intravenous iron in patients with HFrEF and ID was eligible for inclusion. A complete search of the EMBASE and PubMed databases was conducted from inception until 15 September 2023. The primary outcome was the composite of the quality of life (QoL) questionnaires, while the secondary outcomes included first heart failure (HF) hospitalizations and all-cause mortality. Data extraction was performed independently by two reviewers. Data were pooled using a random-effects model.

RESULTS

Of the 1035 references, 15 RCTs enrolling 6649 patients were included in this study. Intravenous iron was associated with significant improvement in the composite of QoL (standardized mean difference - 1.36, 95% confidence interval [CI] - 2.24 to - 0.48; p = 0.002), a significant reduction in first HF hospitalizations (hazard ratio [HR] 0.73, 95% CI 0.56-0.95; p = 0.02), and with no change in all-cause mortality (HR 0.90, 95% CI 0.79-1.03; p = 0.12). The certainty of the evidence ranged from moderate to very low.

CONCLUSION

Intravenous iron is possibly associated with improved QoL and reduced HF hospitalizations, without impacting all-cause mortality. These findings not only support the use of intravenous iron in patients with HFrEF but also emphasize the need for well-designed and executed RCTs with granular outcome reporting and powered sufficiently to address the impact of intravenous iron on mortality in patients with HFrEF and ID.

REGISTRATION

PROSPERO identifier number CRD42023389.

Considerations Regarding Management of Heart Failure in Older Adults

Understanding noncardiovascular comorbidities and geriatric syndromes in elderly patients with heart failure (HF) is important as the average age of the population increases. Healthcare professionals need to consider these complex dynamics when managing older adults with HF, especially those older than 80. A number of small studies have described associations between HF and major geriatric domains. With information on patients' cognitive, functional decline, and ability to adhere to therapy, physicians can plan for individualized treatment goals and recommendations for these patients.

Cardiorenal syndrome and iron supplementation-more benefits than risks: a narrative review

Intravenous iron administration has emerged as a crucial intervention for managing patients with cardiorenal syndrome (CRS) and iron deficiency, with or without the presence of anemia. Multiple studies have demonstrated the benefits of intravenous iron supplementation in improving anemia, symptoms, and functional capacity in patients with HF and iron deficiency. Furthermore, iron supplementation has been associated with a reduction in hospitalizations for HF exacerbation and the improvement of patients' quality of life and clinical outcomes. In addition to its effects on HF management, emerging evidence suggests a potential positive impact on kidney function in patients with CRS. Studies have shown an increase in estimated glomerular filtration rate and improvements in renal function markers in patients receiving intravenous iron therapy, highlighting the potential of this intervention in patients with CRS. This paper reviews the existing literature on the impact of intravenous iron therapy in these patient populations and explores its effects on various clinical outcomes. Future research endeavors are eagerly awaited to further improve our understanding of its clinical implications and optimize patient outcomes.

2023 Focused Update of the 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: Developed by the task force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC) With the special contribution of the Heart Failure Association (HFA) of the ESC

Document Reviewers: Rudolf A. de Boer (CPG Review Co-ordinator) (Netherlands), P. Christian Schulze (CPG Review Co-ordinator) (Germany), Elena Arbelo (Spain), Jozef Bartunek (Belgium), Johann Bauersachs (Germany), Michael A. Borger (Germany), Sergio Buccheri (Sweden), Elisabetta Cerbai (Italy), Erwan Donal (France), Frank Edelmann (Germany), Gloria Färber (Germany), Bettina Heidecker (Germany), Borja Ibanez (Spain), Stefan James (Sweden), Lars Køber (Denmark), Konstantinos C. Koskinas (Switzerland), Josep Masip (Spain), John William McEvoy (Ireland), Robert Mentz (United States of America), Borislava Mihaylova (United Kingdom), Jacob Eifer Møller (Denmark), Wilfried Mullens (Belgium), Lis Neubeck (United Kingdom), Jens Cosedis Nielsen (Denmark), Agnes A. Pasquet (Belgium), Piotr Ponikowski (Poland), Eva Prescott (Denmark), Amina Rakisheva (Kazakhstan), Bianca Rocca (Italy), Xavier Rossello (Spain), Leyla Elif Sade (United States of America/Türkiye), Hannah Schaubroeck (Belgium), Elena Tessitore (Switzerland), Mariya Tokmakova (Bulgaria), Peter van der Meer (Netherlands), Isabelle C. Van Gelder (Netherlands), Mattias Van Heetvelde (Belgium), Christiaan Vrints (Belgium), Matthias Wilhelm (Switzerland), Adam Witkowski (Poland), and Katja Zeppenfeld (Netherlands) All experts involved in the development of this Focused Update have submitted declarations of interest. These have been compiled in a report and simultaneously published in a supplementary document to the Focused Update. The report is also available on the ESC website www.escardio.org/guidelines See the European Heart Journal online for supplementary documents that include evidence tables.

Iron Dyshomeostasis and Mitochondrial Function in the Failing Heart: A Review of the Literature

Cardiac contraction and relaxation require a substantial amount of energy provided by the mitochondria. The failing heart is adenosine triphosphate (ATP)- and creatine-depleted. Studies have found iron is involved in almost every aspect of mitochondrial function, and previous studies have shown myocardial iron deficiency in heart failure (HF). Many clinicians advocated intravenous iron repletion for HF patients meeting the conventional criteria for systemic iron deficiency. While clinical trials showed improved quality of life, iron repletion failed to significantly impact survival or significant cardiovascular adverse events. There is evidence that in HF, labile iron is trapped inside the mitochondria causing oxidative stress and lipid peroxidation. There is also compelling preclinical evidence demonstrating the detrimental effects of both iron overload and depletion on cardiomyocyte function. We reviewed the mechanisms governing myocardial and mitochondrial iron content. Mitochondrial dynamics (i.e., fusion, fission, mitophagy) and the role of iron were also investigated. Ferroptosis, as an important regulated cell death mechanism involved in cardiomyocyte loss, was reviewed along with agents used to manipulate it. The membrane stability and iron content of mitochondria can be altered by many agents. Some studies are showing promising improvement in the cardiomyocyte function after iron chelation by deferiprone; however, whether the in vitro and in vivo findings will be reflected on on clinical grounds is still unclear. Finally, we briefly reviewed the clinical trials on intravenous iron repletion. There is a need for more well-simulated animal studies to shed light on the safety and efficacy of chelation agents and pave the road for clinical studies.

Intravenous Iron for Heart Failure: Updated Systematic Review and Meta-Analysis

While the administration of intravenous (IV) iron to those with heart failure has been implicated to be associated with a possible reduction in hospitalizations and improvement in symptoms, a recent large multicenter trial only showed modest benefits in reducing hospitalization, necessitating the updated systematic review. We conducted a systematic review and meta-analysis, searching the MEDLINE and EMBASE database until January 9, 2023. Outcomes included total heart failure hospitalizations, first heart failure hospitalization, six-minute walk test (6MWT) distance, and incidence of infection. There were 13 studies with 3410 participants (1,790 with IV iron). Pooled analysis that reported the incidence of cardiovascular death showed that patients with IV iron did not have significantly lower odds of cardiovascular death or first heart failure hospitalization. In contrast, those who received IV iron had significantly lower total heart failure hospitalization (pooled odds ratio (OR) 0.63, 95% confidence interval (CI) 0.44-0.90, I2 59.0%, P = .017) and a composite of cardiovascular death and first heart failure hospitalization (pooled OR 0.55, 95% CI 0.47-0.64, I2 0%, P = .656). While the efficacy is modest, IV iron therapy could be associated with reduced hospitalization for heart failure without significant adverse events.

Understanding the Interplay between Iron Deficiency and Congestive Heart Failure: A comprehensive review

Iron is an essential micronutrient for abounding physiological processes in the body, and its deficiency can be caused by various factors, such as low iron intake due to economic difficulties or loss of appetite, decreased iron absorption due to gastrointestinal issues, or increased iron loss due to hemorrhages or proteinuria. Iron deficiency is a prevalent issue among heart failure (HF) patients and is a significant contributor to anemia, affecting 30-50% of patients regardless of their gender, ethnicity, or left ventricular ejection fraction. Individuals with HF have high levels of pro-inflammatory cytokines, which can inhibit erythropoiesis by degrading the membrane iron exporter ferroportin, mediated by an increased release of hepcidin. In addition, elevated sympathetic and renin-angiotensin-aldosterone system activity retains salt and water, resulting in high cardiac output HF in people with normal left ventricular function. This review provides an overview of iron deficiency and HF.

Effect of intravenous iron replacement on recurrent heart failure hospitalizations and cardiovascular mortality in patients with heart failure and iron deficiency: A Bayesian meta-analysis

AIMS

Iron deficiency is common in patients with heart failure (HF) and reduced ejection fraction (HFrEF) and is associated with a poor prognosis. Whether intravenous iron replacement improves recurrent HF hospitalizations and cardiovascular mortality of these patients is uncertain although several trials were conducted. Moreover, none of the trials were powered to assess the effect of intravenous iron in clinically important subgroups. Therefore, we conducted a Bayesian analysis to derive precise estimates of the effect of intravenous iron replacement on recurrent HF hospitalizations and cardiovascular mortality in iron-deficient HFrEF patients using consistent subgroup definitions across trials.

METHODS AND RESULTS

Individual participant data were used from the FAIR-HF (n = 459), CONFIRM-HF (n = 304) and AFFIRM-AHF (n = 1108) trials. These data were re-analysed following as closely as possible the approach taken in the analyses of IRONMAN (n = 1137), for which study level data were used. Definitions of outcomes and subgroups from the FAIR-HF, CONFIRM-HF and AFFIRM-AHF were matched with those used in IRONMAN. The primary endpoint was recurrent HF hospitalizations and cardiovascular mortality. The analysis of recurrent events was based on rate ratios (RR) derived from the Lin-Wei-Yang-Ying model, and the data were pooled using Bayesian random-effects meta-analysis. Compared with placebo, intravenous iron significantly reduced the rates of recurrent HF hospitalizations and cardiovascular mortality (RR 0.73, 95% credible interval [CI] 0.48-0.99; between-trial heterogeneity tau = 0.16). The pooled treatment effects did not provide evidence for any differential effects for subgroups based on sex (ratio of rate ratios [RRR] 1.49 [95% CI 0.95-2.37], age <69.4 vs. ≥69.4 years) (RRR 0.68 [0.40-1.15]), ischaemic versus non-ischaemic aetiology of HF (RRR 0.73 [0.42-1.33]), transferrin saturation <20% vs. ≥20% (RRR 0.75 [0.40-1.34]), estimated glomerular filtration rate ≤60 versus >60 ml/min/1.73 m2 (RRR 0.97 [0.56-1.68]), haemoglobin <11.8 versus ≥11.8 (RRR 0.95 [0.53-1.60]), ferritin <35 versus ≥35 μg/L (RRR 1.26 [0.72-2.48]) and New York Heart Association class II versus III/IV (RRR 0.91 [0.54-1.56]).

CONCLUSIONS

Treatment of iron-deficient HFrEF patients with intravenous iron - namely with ferric carboxymaltose or ferric derisomaltose - results in significant reduction in recurrent HF hospitalizations and cardiovascular mortality. Results were nominally consistent across the subgroups studied, but for several of these subgroups uncertainty remains present.

Intravenous iron therapy among patients with heart failure and iron deficiency: An updated meta-analysis of randomized controlled trials

Background

Randomized clinical trials (RCTs) evaluating the role of intravenous (IV) iron administration in patients with heart failure (HF) and iron deficiency (ID) have yielded inconsistent results.

Methods

Electronic search of MEDLINE, EMBASE and OVID databases was performed until November 2022 for RCTs that evaluated the role of IV iron administration in patients with HF and ID. The main study outcomes were the composite of HF hospitalization or cardiovascular mortality, and individual outcome of HF hospitalization. Summary estimates were evaluated using random effects model.

Results

The final analysis included 12 RCTs with 3,492 patients (1,831 patients in the IV iron group and 1,661 patients in the control group). The mean follow-up was 8.3 months. IV iron was associated with a lower incidence in the composite of HF hospitalization or cardiovascular mortality (31.9% vs. 45.3%; relative risk [RR] 0.72; 95% confidence interval [CI] 0.59-0.88) and individual outcome of HF hospitalization (28.4% vs. 42.2; RR 0.69; 95% CI 0.57-0.85). There was no significant difference between both groups in cardiovascular mortality (RR 0.88; 95% CI 0.75-1.04) and all-cause mortality (RR 0.95; 95% CI 0.83-1.09). IV iron was associated with lower New York Heart Association class and higher left ventricular ejection fraction (LVEF). Meta-regression analyses showed no effect modification for the main outcomes based on age, hemoglobin level, ferritin level or LVEF.

Conclusion

Among patients with HF and ID, IV iron administration was associated with reduction in the composite of HF hospitalization or cardiovascular mortality and driven by a reduction in HF hospitalization.

Nutritional Aspects of Iron in Health and Disease

Dietary iron assimilation is critical for health and essential to prevent iron-deficient states and related comorbidities, such as anemia. The bioavailability of iron is generally low, while its absorption and metabolism are tightly controlled to satisfy metabolic needs and prevent toxicity of excessive iron accumulation. Iron entry into the bloodstream is limited by hepcidin, the iron regulatory hormone. Hepcidin deficiency due to loss-of-function mutations in upstream gene regulators causes hereditary hemochromatosis, an endocrine disorder of iron overload characterized by chronic hyperabsorption of dietary iron, with deleterious clinical complications if untreated. The impact of high dietary iron intake and elevated body iron stores in the general population is not well understood. Herein, we summarize epidemiological data suggesting that a high intake of heme iron, which is abundant in meat products, poses a risk factor for metabolic syndrome pathologies, cardiovascular diseases, and some cancers. We discuss the clinical relevance and potential limitations of data from cohort studies, as well as the need to establish causality and elucidate molecular mechanisms.