Iron Deficiency in Heart Failure: A Scientific Statement from the Heart Failure Society of America

Metabolic cycles: A unifying concept for energy transfer in the heart

It is still debated whether changes in metabolic flux are cause or consequence of contractile dysfunction in non-ischemic heart disease. We have previously proposed a model of cardiac metabolism grounded in a series of six moiety-conserved, interconnected cycles. In view of a recent interest to augment oxygen availability in heart failure through iron supplementation, we integrated this intervention in terms of moiety conservation. Examining published work from both human and murine models, we argue this strategy restores a mitochondrial cycle of energy transfer by enhancing mitochondrial pyruvate carrier (MPC) expression and providing pyruvate as a substrate for carboxylation and anaplerosis. Metabolomic data from failing heart muscle reveal elevated pyruvate levels with a concomitant decrease in the levels of Krebs cycle intermediates. Additionally, MPC is downregulated in the same failing hearts, as well as under hypoxic conditions. MPC expression increases upon mechanical unloading in the failing human heart, as does contractile function. We note that MPC deficiency also alters expression of enzymes involved in pyruvate carboxylation and decarboxylation, increases intermediates of biosynthetic pathways, and eventually leads to cardiac hypertrophy and dilated cardiomyopathy. Collectively, we propose that an unbroken chain of moiety-conserved cycles facilitates energy transfer in the heart. We refer to the transport and subsequent carboxylation of pyruvate in the mitochondrial matrix as an example and a proposed target for metabolic support to reverse impaired contractile function.

Association of Iron Therapy with Mortality in Patients with Acute Myocardial Infarction and Iron Deficiency

Iron deficiency (ID) is common in patients with acute myocardial infarction (AMI). It is unknown whether patients with AMI combined with ID will benefit from iron supplementation therapy. This study aimed to assess the relationship between iron therapy and mortality in AMI patients. Retrospective analysis was performed in subjects screened from the Medical Information Mart in Intensive Care-IV database. The data were obtained from ICU patients admitted to Beth Israel Deaconess Medical Center between 2008 and 2019. The patients were divided into two groups according to iron treatment exposure. Propensity score matching (PSM) was performed in the original cohort at a 1:1 ratio. Univariate and multivariate analyses were performed to adjust for confounding factors. The primary outcome was 28-day mortality. A total of 426 patients were included in this study. After 1:1 PSM, 208 patients were analyzed. Iron treatment was associated with a lower risk of 28-day mortality (9 deaths (8.65%) in the iron treatment group vs. 21 deaths (20.19%) in the non-iron treatment group; HR = 0.39; 95% CI = 0.17-0.89; p = 0.025) and in-hospital mortality (4 deaths (3.85%) in the iron treatment group vs. 12 deaths (11.54%) in the non-iron treatment group; OR, 0.15; 95% CI, 0.03-0.74; p = 0.029). Iron treatment was associated with reduced 28-day mortality in patients with AMI combined with ID. Iron treatment had no significant effect on the length of hospitalization or the length of ICU stay. Prospective studies are needed to verify this conclusion.

Associations of iron metabolism and inflammation with all-cause and cardiovascular mortality in a large NHANES community sample: Moderating and mediating effects

BACKGROUND AND AIMS

This study aimed to assess the associations between serum iron concentration, C-reactive protein (CRP) concentration and the risk of all-cause mortality and cardiovascular mortality in the general population and to explore potential mediating and moderating effects.

METHODS AND RESULTS

This study analyzed data from the National Health and Nutrition Examination Survey spanning the years 1999-2010, encompassing 23,634 participants. Cox proportional hazards regression models were employed to investigate the independent associations of serum iron and CRP with all-cause and cardiovascular mortality. Moderation and mediation analyses explored the moderating effect of CRP on the association between the serum iron concentration and all-cause and cardiovascular mortality, and the mediating role of the serum iron concentration in the association between the CRP concentration and all-cause and cardiovascular mortality. After multivariate adjustments in the Cox model, serum iron and CRP levels were independently correlated with both all-cause and cardiovascular mortality risk. Moderation analyses revealed a more pronounced correlation between the serum iron concentration and both all-cause and cardiovascular mortality in participants with higher CRP levels. Mediation analysis indicated that the serum iron concentration partly mediated the impact of CRP on the risk of all-cause mortality (13.79%) and cardiovascular mortality (24.12%).

CONCLUSION

Serum iron and CRP are independently associated with all-cause and cardiovascular mortality. Moreover, the associations between serum iron concentrations and both all-cause and cardiovascular mortality are more pronounced in individuals with elevated CRP. Serum iron partially mediates the effect of CRP on all-cause and cardiovascular mortality.

Iron deficiency and all-cause mortality after myocardial infarction

BACKGROUND

Data on the clinical significance of iron deficiency (ID) in patients with myocardial infarction (MI) are conflicting. This may be related to the use of various ID criteria. We aimed to compare the association of different ID criteria with all-cause mortality after MI.

METHODS

Consecutive patients hospitalized for their first MI at a large tertiary heart center were included. We evaluated the association of different iron metabolism parameters measured on the first day after hospital admission with all-cause mortality.

RESULTS

From the 1,156 patients included (aged 64±12 years, 25 % women), 194 (16.8 %) patients died during the median follow-up of 3.4 years. After multivariate adjustment, iron level ≤13 µmol/L (HR 1.67, 95 % CI 1.19-2.34) and the combination of iron level ≤12.8 µmol/L and soluble transferrin receptor (sTfR) ≥3 mg/L (HR 2.56, 95 % CI 1.64-3.99) termed as PragueID criteria were associated with increased mortality risk and had additional predictive value to the GRACE score. Compared to the model including iron level, the addition of sTfR improved risk stratification (net reclassification improvement 0.61, 95 % CI 0.52-0.69) by reclassifying patients into a higher-risk group. No association between ferritin level and mortality was found. 51 % of patients had low iron levels, and 58 % fulfilled the PragueID criteria.

CONCLUSION

Iron deficiency is common among patients with the first MI. The PragueID criteria based on iron and soluble transferrin receptor levels provide the best prediction of mortality and should be evaluated in future interventional studies for the identification of patients potentially benefiting from intravenous iron therapy.

Management of Iron Deficiency in Heart Failure: Practical Considerations and Implementation of Evidence-Based Iron Supplementation

Iron deficiency (ID) is present in approximately 50% of patients with heart failure (HF) and even higher prevalence rate up to 80% in post-acute HF setting. The current guidelines for HF recommend intravenous (IV) iron replacement in HF with reduced or mildly reduced ejection fraction and ID based on clinical trials showing improvements in quality of life and exercise capacity, and an overall treatment benefit for recurrent HF hospitalization. However, several barriers cause challenges in implementing IV iron supplementation in practice due, in part, to clinician knowledge gaps and limited resource availability to protocolize routine utilization in appropriate patients. Thus, the current review will discuss practical considerations in ID treatment, implementation of evidence-based ID treatment to improve regional health disparities with toolkits, inclusion/exclusion criteria of IV iron supplementation, and clinical controversies in ID treatment, as well as gaps in evidence and questions to be answered.

Critical re-evaluation of the identification of iron deficiency states and effective iron repletion strategies in patients with chronic heart failure

According to current guidelines, iron deficiency is defined by a serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 μg/L. These criteria were developed to encourage the use of intravenous iron as an adjunct to erythropoiesis-stimulating agents in the treatment of renal anaemia. However, in patients with heart failure, these criteria are not supported by any pathophysiological or clinical evidence that they identify an absolute or functional iron deficiency state. A low baseline TSAT-but not serum ferritin level-appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events. In randomized controlled trials, intravenous iron decreased the risk of cardiovascular death or total heart failure hospitalization in patients with a TSAT <20% (risk ratio 0.67 [0.49-0.92]) but not in patients with a TSAT ≥20% (risk ratio 0.99 [0.74-1.30]), with the magnitude of the risk reduction being proportional to the severity of hypoferraemia. Patients who were enrolled in clinical trials solely because they had a serum ferritin level <100 μg/L showed no significant benefit on heart failure outcomes, and it is noteworthy that serum ferritin levels of 20-300 μg/L lie entirely within the range of normal values for healthy adults. Current guidelines reflect the eligibility criteria of clinical trials, which inadvertently adopted unvalidated criteria to define iron deficiency. Reliance on these guidelines would lead to the treatment of many patients who are not iron deficient (serum ferritin level <100 μg/L but normal TSAT) and ignores the possibility of iron deficiency in patients with a low TSAT but with serum ferritin level of >300 μg/L. Importantly, analyses of benefit based on trial eligibility-driven guidelines substantially underestimate the magnitude of heart-failure-event risk reduction with intravenous iron in patients who are truly iron deficient. Based on all available data, we recommend a new mechanism-based and trial-tested approach that reflects the totality of evidence more faithfully than the historical process adopted by clinical investigators and by the guidelines. Until additional evidence is forthcoming, an iron deficiency state in patients with heart failure should be defined by a TSAT <20% (as long as the serum ferritin level is <400 μg/L), and furthermore, the use of a serum ferritin level <100 μg/L alone as a diagnostic criterion should be discarded.

Challenges and opportunities in patients with adult congenital heart disease, a narrative review

Adult congenital heart disease Pregnancy Transition of care Challenges heart failure.

Analysis of Genes Involved in Oxidative Stress and Iron Metabolism in Heart Failure: A Step Forward in Risk Stratification

INTRODUCTION

Heart failure (HF) is a clinical syndrome characterized by cardinal symptoms that may be accompanied by signs. It results from structural and/or functional abnormalities of the heart leading to elevated intracardiac pressures and/or inadequate cardiac output at rest and/or during exercise. The prevalence of iron deficiency and anemia justifies the current guidelines recommendation of screening. Genes HP, ACE, MTHFR, HFE, and CYBA are involved in oxidative mechanisms, iron metabolism, and hematologic homeostasis. This study investigates the contribution of variants Hp1/2 (HP), I/D (ACE), C677T (MTHFR), C282Y and H63D (HFE), and C242T (CYBA) to the development of HF, either independently or in epistasis.

METHODS

We used a database of 389 individuals, 143 HF patients, and 246 healthy controls. Genotypes were characterized through PAGE electrophoresis, PCR, PCR-RFLP, and multiplex-ARMS. Data analysis was performed with the SPSS® 26.0 software (IBM Corp., Armonk, NY).

RESULTS

We observed a significant association between the MTHFR gene and HF predisposition. The presence of allele T and genotype CT constituted risk, while genotype CC granted protection. Epistatic interactions revealed risk between genotype II of the ACE gene and genotypes CC (C282Y) or HH (H63D) of the HFE gene. Risk was also observed for interactions between genotype CC (CYBA)and genotypes 2-2 (HP), CT (MTHFR), or HH (HFE-H63D).

CONCLUSION

We concluded that genes HP, ACE, MTHFR, HFE, and CYBA contribute to the susceptibility for HF, individually or in epistasis. This study contributes to the clarification of the role that genes involved in oxidative mechanisms and iron metabolism play in the physiopathology of HF. It is, therefore, a step forward in risk stratification and personalized medicine.

Intravenous iron in patients with iron deficiency and heart failure: a review of modern evidence

PURPOSE OF REVIEW

Iron deficiency is common in patients with heart failure, affecting up to half of ambulatory patients and an even greater percentage of patients admitted for acute decompensation. Iron deficiency in this population is also associated with poor outcomes, including worse quality of life in addition to increased hospitalizations for heart failure and mortality. Evidence suggests that patients with iron deficiency in heart failure may benefit from repletion with IV iron.

RECENT FINDINGS

In this review, we outline the etiology and pathophysiology of iron deficiency in heart failure as well as various iron formulations available. We discuss evidence for intravenous iron repletion with a particular focus on recent studies that have evaluated its effects on hospitalizations and mortality. Finally, we discuss areas of uncertainty and future study and provide practical guidance for iron repletion.

SUMMARY

In summary, there is overwhelming evidence that intravenous iron repletion in patients with iron deficiency in heart failure is both beneficial and safe. However, further evidence is needed to better identify which patients would most benefit from iron repletion as well as the ideal repletion strategy.

Acute Heart Failure: From The Emergency Department to the Intensive Care Unit

Acute heart failure (AHF) is a frequent cause of hospitalization around the world and is associated with high in-hospital and post-discharge morbidity and mortality. This review summarizes data on diagnosis and management of AHF from the emergency department to the intensive care unit. While more evidence is needed to guide risk stratification and care of patients with AHF, hospitalization is a key opportunity to optimize evidence-based medical therapy for heart failure. Close linkage to outpatient care is essential to improve post-hospitalization outcomes.

Temporal Analysis in Outcomes of Long-Term Mechanical Circulatory Support: Retrospective Study

BACKGROUND

 Mechanical assist device indications have changed in recent years. Reduced incidence of complications, better survival, and the third generation of mechanical support devices contributed to this change. In this single-center study, we focused on two time periods that are characterized by the use of different types of mechanical support devices, different patient characteristics, and change in the indications.

METHODS

 The data were processed from the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). We retrospectively defined two time intervals to reflect changes in ventricular assist device technology (period 1: 2007-2015; period 2: 2016-20222). A total of 181 patients underwent left ventricular assist device implantation. Device utilization was the following: HeartMate II = 52 (76.4%) and HeartWare = 16 (23.6%) in period 1 and HeartMate II = 2 (1.8%), HeartMate 3 = 70 (61:9%), HeartWare = 29 (25.7%), SynCardia TAH = 10 (8.8%), and BerlinHeart EXCOR = 2 (1.8%) in period 2. The outcomes of the time intervals were analyzed and evaluated.

RESULTS

 Survival was significantly higher during the second time period. Multivariate analysis revealed that age and bypass pump time are independent predictors of mortality. Idiopathic cardiomyopathy, bypass time, and the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) score are independent predictors of adverse events. Furthermore, the first period was noted to be at an increased risk of the following adverse events: pump thrombosis, gastrointestinal bleeding, and bleeding events.

CONCLUSION

 Despite the higher risk profile of the patients and persistent challenges, during the second period, there was a significant decrease in mortality and morbidity. The use of the HeartMate 3 device may have contributed to this result.

Iron Metabolic Biomarkers and the Mortality Risk in the General Population: A Nationwide Population-Based Cohort Study

Context

Iron is an essential element in the human body and plays a critical role in many physiological and cellular processes. However, the association between iron status and the risk of all-cause or cause-specific mortality has not been well-investigated. And it is unclear whether the association between iron metabolic biomarkers and the risk of mortality differs between people with and without diabetes mellitus (DM).

Objective

This work aimed to investigate associations between iron metabolic biomarkers and all-cause and cause-specific mortality risk in the general population, and heterogeneities in the associations among population with and without DM..

Methods

A total of 29 166 adults from the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999 to 2010 were included, with linkage to the National Death Index to December 31, 2019. Cox proportional-hazard models and Fine-Gray subdistribution hazard models were used to estimate associations between iron metabolic biomarkers and outcomes.

Results

During a median follow-up of 18.83 years, 9378 deaths were observed, including 3420 cardiovascular disease (CVD) deaths and 1969 cancer deaths. A significant linear association between serum ferritin (SF) and all-cause mortality was observed among the overall population and those without DM. J-shaped associations between transferrin saturation (TSAT) and all-cause and CVD mortality were observed among all populations. In the overall population, compared to the first quartile (Q1) group, the adjusted hazard ratio (HR) (95% CI) for all-cause mortality was 1.07 (1.00-1.15), 1.05 (0.98-1.12), 1.13 (1.05-1.21) in Q2, Q3, and Q4 groups for SF, while the HR was 0.94 (0.88-0.99), 0.92 (0.86-0.97), and 0.93 (0.88-0.99) for TSAT. In individuals without DM, the adjusted HR of the Q4 of SF were 1.19 (1.03-1.37) for CVD mortality and 1.25 (1.05-1.48) for cancer mortality. In individuals with DM, the adjusted HRs of the Q4 of TSAT were 0.76 (0.62-0.93) for CVD mortality and 1.47 (1.07-2.03) for cancer mortality.

Conclusion

Iron metabolism abnormalities increase mortality risk in the general population. The associations of iron status with mortality were significantly different between individuals with and without DM, which indicated tailored strategies for iron homeostasis are needed.

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.

[The Effects of Therapy for Iron Deficiency in Patients With Different Etiologies of Heart Failure and Concomitant Diseases]

Iron deficiency (ID) in patients with heart failure (HF) is a factor for unfavorable course and prognosis of the disease. The significance of ID in the diagnosis and treatment of HF has previously been demonstrated by multiple studies and meta-analyses. Therapy for ID in patients with HF is one of the most relevant and discussed issues. The use of intravenous iron medicinal products for the treatment of ID is currently being actively studied in patients of various categories; attempts are being made to specify the indications for use to produce the greatest effect on the prognosis and quality of life of HF patients.

Ferric Carboxymaltose in Heart Failure with Iron Deficiency

BACKGROUND

Ferric carboxymaltose therapy reduces symptoms and improves quality of life in patients who have heart failure with a reduced ejection fraction and iron deficiency. Additional evidence about the effects of ferric carboxymaltose on clinical events is needed.

METHODS

In this double-blind, randomized trial, we assigned ambulatory patients with heart failure, a left ventricular ejection fraction of 40% or less, and iron deficiency, in a 1:1 ratio, to receive intravenous ferric carboxymaltose or placebo, in addition to standard therapy for heart failure. Ferric carboxymaltose or placebo was given every 6 months as needed on the basis of iron indexes and hemoglobin levels. The primary outcome was a hierarchical composite of death within 12 months after randomization, hospitalizations for heart failure within 12 months after randomization, or change from baseline to 6 months in the 6-minute walk distance. The significance level was set at 0.01.

RESULTS

We enrolled 3065 patients, of whom 1532 were randomly assigned to the ferric carboxymaltose group and 1533 to the placebo group. Death by month 12 occurred in 131 patients (8.6%) in the ferric carboxymaltose group and 158 (10.3%) in the placebo group; a total of 297 and 332 hospitalizations for heart failure, respectively, occurred by month 12; and the mean (±SD) change from baseline to 6 months in the 6-minute walk distance was 8±60 and 4±59 m, respectively (Wilcoxon-Mann-Whitney P = 0.02; unmatched win ratio, 1.10; 99% confidence interval, 0.99 to 1.23). Repeated dosing of ferric carboxymaltose appeared to be safe with an acceptable adverse-event profile in the majority of patients. The number of patients with serious adverse events occurring during the treatment period was similar in the two groups (413 patients [27.0%] in the ferric carboxymaltose group and 401 [26.2%] in the placebo group).

CONCLUSIONS

Among ambulatory patients who had heart failure with a reduced ejection fraction and iron deficiency, there was no apparent difference between ferric carboxymaltose and placebo with respect to the hierarchical composite of death, hospitalizations for heart failure, or 6-minute walk distance. (Funded by American Regent, a Daiichi Sankyo Group company; HEART-FID ClinicalTrials.gov number, NCT03037931.).