Impact of Iron Deficiency on Response to and Remodeling After Cardiac Resynchronization Therapy

The Impact of Iron Deficiency on Disease Severity and Myocardial Function in Cardiac Amyloidosis

Background

Reduced cardiac energy is a hallmark feature of heart failure and is common in cardiac amyloidosis (CA) and can be aggravated by the presence of iron deficiency.

Methods

Retrospective analysis of a single tertiary care center CA registry. Prevalence of iron deficiency was determined based on two definitions: (1) Classic definition, ferritin < 100 µg/L irrespective of transferin saturation (TSAT) or ferritin between 100 and 300 µg/L with a TSAT < 20%, and (2) TSAT-based definition, TSAT < 20%.

Results

Out of a total of 393 CA patients who had a full set of iron indices (44% light chain [AL]-CA, 50% transthyretin [ATTR]-CA, remainder other or unspecified CA subtype), 56% had iron deficiency according to the classic definition and 58% according to the TSAT definition, with similar prevalence in AL-CA vs ATTR-CA (p = .135). Per both definitions 58% had anemia. Only the TSAT-based definition was associated with worse functional status (p = .039) and worse cardiac function. CA patients with a TSAT < 20% illustrated features of more pronounced right ventricular (RV) failure including lower TAPSE on echocardiography, lower RV ejection fraction and RV stroke volume index on CMR, increased right-sided filling pressures, lower pulmonary artery pulsatility index, and higher RAP/PCWP ratio by right heart catheterization. Neither the classic nor the TSAT-based definition was associated with a higher risk of all-cause mortality after covariate adjustment.

Conclusion

Iron deficiency is common in cardiac amyloidosis and, when identified with a TSAT < 20%, is associated with worse functional status and more pronounced RV disease, but not with a higher risk of all-cause mortality.

Intravenous iron for acute and chronic heart failure with reduced ejection fraction (HFrEF) patients with iron deficiency: An updated systematic review and meta-analysis

Patients with heart failure (HF) and iron deficiency are at increased risk of adverse clinical outcomes. We searched databases for randomised controlled trials that compared IV iron to placebo, in patients with HF with reduced ejection fraction (HFrEF). A total of 7,813 participants, all having HFrEF with 3,998 receiving IV iron therapy, and 3,815 control recipients were included. There was a significant improvement in Kansas City Cardiomyopathy Questionnaire favouring IV iron with MD 7.39, 95% CI [3.55, 11.22], p = 0.0002. Subgroup analysis, based on acute and chronic HF, has displayed a sustained statistical significance. Additionally, a significant increase in the left ventricular ejection fraction % was observed, with MD 3.76, 95% CI [2.32, 5.21], p < 0.00001. A significant improvement in 6-min walk test was noted, with MD 34.87, 95% CI [20.02, 49.72], p < 0.00001. Furthermore, IV iron showed significant improvement in NYHA class, peak VO2, serum ferritin, and haemoglobin levels. Finally, despite the lack of difference in terms of all-cause hospitalisation and HF-related death, IV iron was associated with a significant reduction in HF-related, any cardiovascular reason hospitalisations, and all-cause death; which supports the need for implementation of IV iron as a standard of care in patients with HF and iron deficiency.

Meta-Analysis and Metaregression of the Treatment Effect of Intravenous Iron in Iron-Deficient Heart Failure

BACKGROUND

Guidelines recommend that intravenous iron should be considered to improve symptoms of heart failure (HF) and reduce the risk for HF admissions in patients after acute HF.

OBJECTIVES

This study sought to analyze the effect of intravenous iron on cardiovascular (CV) death and HF admissions in a broad population of HF patients with iron deficiency and the relation with baseline transferrin saturation (TSAT).

METHODS

A systematic review of all published randomized controlled trials assessing the effect of intravenous iron in patients with iron deficiency and HF between January 1, 2000, and August 26, 2023, was performed. The overall treatment effect was estimated using a fixed effect model for: 1) CV death; 2) CV death and HF admission; 3) first HF admission; and 4) total HF admissions. Metaregression through a mixed effect model was used to explore the impact of baseline TSAT in case of heterogeneity among trial results.

RESULTS

A total of 14 randomized controlled trials were identified in the systematic review and retained in the meta-analysis. Aggregate-level data were included on 6,624 HF patients, 3,407 of whom were randomized to intravenous iron and 3,217 to placebo. Treatment with intravenous iron resulted in a lower risk for CV death (OR: 0.867 [95% CI: 0.755-0.955]; P = 0.0427), combined CV death and HF admission (OR: 0.838 [95% CI: 0.751-0.936]; P = 0.0015), first HF admission (OR: 0.855 [95% CI: 0.744-0.983]; P = 0.0281), and total HF admissions (rate ratio: 0.739 [95% CI: 0.661-0.827]; P < 0.0001). Significant heterogeneity among trial results was observed for first and total HF admissions. Metaregression suggested that some of the heterogeneity was related to the baseline TSAT of the enrolled population, with trials enrolling patients with lower TSAT exhibiting a large effect size on HF-related events.

CONCLUSIONS

The totality of data suggests that treatment with intravenous iron reduces both CV death and HF-related events in a broad population with HF. A lower baseline TSAT might be important for the effect on HF-related events.

Pre-emptive iron supplementation prevents myocardial iron deficiency and attenuates adverse remodelling after myocardial infarction

AIMS

Heart failure (HF) after myocardial infarction (MI) is a major cause of morbidity and mortality. We sought to investigate the functional importance of cardiac iron status after MI and the potential of pre-emptive iron supplementation in preventing cardiac iron deficiency (ID) and attenuating left ventricular (LV) remodelling.

METHODS AND RESULTS

MI was induced in C57BL/6J male mice by left anterior descending coronary artery ligation. Cardiac iron status in the non-infarcted LV myocardium was dynamically regulated after MI: non-haem iron and ferritin increased at 4 weeks but decreased at 24 weeks after MI. Cardiac ID at 24 weeks was associated with reduced expression of iron-dependent electron transport chain (ETC) Complex I compared with sham-operated mice. Hepcidin expression in the non-infarcted LV myocardium was elevated at 4 weeks and suppressed at 24 weeks. Hepcidin suppression at 24 weeks was accompanied by more abundant expression of membrane-localized ferroportin, the iron exporter, in the non-infarcted LV myocardium. Notably, similarly dysregulated iron homeostasis was observed in LV myocardium from failing human hearts, which displayed lower iron content, reduced hepcidin expression, and increased membrane-bound ferroportin. Injecting ferric carboxymaltose (15 µg/g body weight) intravenously at 12, 16, and 20 weeks after MI preserved cardiac iron content and attenuated LV remodelling and dysfunction at 24 weeks compared with saline-injected mice.

CONCLUSION

We demonstrate, for the first time, that dynamic changes in cardiac iron status after MI are associated with local hepcidin suppression, leading to cardiac ID long term after MI. Pre-emptive iron supplementation maintained cardiac iron content and attenuated adverse remodelling after MI. Our results identify the spontaneous development of cardiac ID as a novel disease mechanism and therapeutic target in post-infarction LV remodelling and HF.

Iron Deficiency in Heart Failure and Pulmonary Hypertension

Purpose of review

To describe the role of iron deficiency in both heart failure and pulmonary hypertension.

Recent findings

To role of iron deficiency in heart failure is well established and pathophysiologic overlap with pulmonary hypertension exists.

Summary

Iron deficiency is common co-morbidity in heart failure and pulmonary hypertension. The high prevalence is intertwined into the pathophysiology of these conditions (e.g., neurohormonal activation, inflammation). The presence of iron deficiency has a negative impact on cardiomyocytes and cardiac function, skeletal muscle function, and pulmonary vascular function. In heart failure data from over 2000 randomized patients with iron deficiency using a uniform diagnosis, have illustrated beneficial effects on functional status, quality of life, reverse cardiac remodeling, and heart failure admissions. While iron deficiency is recognized to be prevalent in pulmonary hypertension and associated with worse functional status, the absence of a uniform definition and the absence of large prospective randomized controlled trials with iron therapies limits the conclusions on the causal role of iron deficiency such as observed in heart failure.

Why Iron Deficiency in Acute Heart Failure Should Be Treated: A Real-World Clinical Practice Study

Background. This study aims to determine whether the administration of ferric carboxymaltose (FCM) in patients with acute heart failure (AHF) and iron deficiency (ID) improves morbidity and mortality. Methods. We studied 890 consecutive patients admitted for AHF. Patients were divided into six groups according to reduced left ventricular ejection fraction (HFrEF) or preserved (HFpEF), presence of ID, and administration of FCM. Emergency visits, re-admissions, and all-cause mortality were assessed at 6 months. Results. The overall prevalence of ID was 91.2%. In the HFrEF group, no differences were found in isolated events when patients with untreated vs. treated ID were compared, while differences were found in the combined event rate (p = 0.049). The risk calculation showed an absolute risk reduction (ARR) of 10% and relative risk reduction (RRR) of 18%. In HFpEF there was a positive trend with regard to the combined event (p = 0.107), with an ARR of 9% and an RRR of 15%. The number of patients we needed to treat to prevent a combined event was 10.5 in HFrEF and 10.8 in HFpEF. Conclusions. FCM in AHF reduced the combined event rate of emergency visits, re-admission, and all-cause death at 6 months in HF with left ventricular ejection fraction <50%, and showed a positive trend in HFpEF.

Multidisciplinary heart failure care program: an experience from Colombia

The prevalence of Heart Failure is growing alarmingly; its treatment consumes health resources and affects the quality of life of patients.

OBJECTIVE

to describe the changes in NYHA functional Class, ejection fraction, hospitalizations and mortality after 8 years of follow up in a multidisciplinary heart failure program in Colombia as a model for lower and middle income countries.

METHODS

An observational study was performed with the retrospective analysis of the information RESULTS: 1757 patients were included, The NYHA functional class at the beginning of the program was: NYHA I 23.5%, NYHA II 50.3%, NYHA class Improvement was observed at the end of the follow-up with an increase in the percentage of patients in Functional Class NYHA I and II. The reduction in hospitalizations were 35% less (mean: 0.68 ± 0.95, p < 0.0001), a reduction in the length of stay in the hospital was 13.2% (before: 4.46 ± 7.16, after 3.87 ± 8.1 days, p < 0.001). The total mortality after eight years of follow-up was 6.6 % (n = 116).

CONCLUSION

Multidisciplinary follow-up in HF programs improves Functional Class and EF, decreases hospital admissions as well as hospitalization and the length of stay. This is a very simple and successful model of care for this disease that can be implemented for countries of lower- and middle-income countries.

What Have We Learned in the Last 20 Years About CRT Non-Responders?

Although cardiac resynchronization therapy (CRT) has become well established in the treatment of heart failure, the management of patients who do not respond after CRT remains a key challenge. This review will summarize what we have learned about non-responders over the last 20 years and discuss methods for optimizing response, including the introduction of novel therapies.

The Effect of Iron Deficiency on Cardiac Function and Structure in Heart Failure with Reduced Ejection Fraction

Over the past decade, the detrimental impact of iron deficiency in heart failure with reduced ejection fraction has become abundantly clear, showing a negative impact on functional status, quality of life, cardiac function and structure, exercise capacity and an increased risk of hospitalisation due to heart failure. Mechanistic studies have shown the impact of iron deficiency in altering mitochondrial function and negatively affecting the already altered cardiac energetics in heart failure with reduced ejection fraction. Such failing energetics form the basis of the alterations to cellular myocyte shortening, culminating in reduced systolic function and cardiac performance. The IRON-CRT trials show that ferric carboxymaltose is capable of improving cardiac structure and cardiac performance. This article discusses the effect of iron deficiency on cardiac function and structure and how it can be alleviated.

Towards a Common Definition for the Diagnosis of Iron Deficiency in Chronic Inflammatory Diseases

Iron deficiency (ID) in patients with chronic inflammatory diseases is frequent. However, under-diagnosis is also frequent due to the heterogeneity between guidelines from different medical societies. We applied a common definition for the diagnosis of ID to a large panel of patients with cancer, heart failure (HF), inflammatory bowel disease (IBD), and chronic kidney disease (CKD), where ID was defined as serum ferritin concentration <100 μg/L and/or a transferrin saturation (TSAT) index <20%. Prevalence estimates using this common definition were compared with that obtained with officially accepted definitions (ESMO 2018, ESC 2016, ECCO 2015, and ERBP 2013). For that purpose, we used data collected during the French CARENFER studies, which included 1232, 1733, 1090, and 1245 patients with cancer, HF, IBD, and CKD, respectively. When applying the common definition, ID prevalence increased to 58.1% (vs. 57.9%), 62.8% (49.6%), and 61.2% (23.7%) in cancer, HF, and IBD patients, respectively. Both prevalence estimates were similar (47.1%) in CKD patients. Based on our results, we recommend combining both ferritin concentration and TSAT index to define ID in patients with chronic inflammatory diseases. In those patients, adopting this common definition of ID should contribute to a better screening for ID, whatever the condition.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

Optimized implementation of cardiac resynchronization therapy: a call for action for referral and optimization of care

Cardiac resynchronization therapy (CRT) is one of the most effective therapies for heart failure with reduced ejection fraction and leads to improved quality of life, reductions in heart failure hospitalization rates and all-cause mortality. Nevertheless, up to two-thirds of eligible patients are not referred for CRT. Furthermore, post-implantation follow-up is often fragmented and suboptimal, hampering the potential maximal treatment effect. This joint position statement from three European Society of Cardiology Associations, Heart Failure Association (HFA), European Heart Rhythm Association (EHRA) and European Association of Cardiovascular Imaging (EACVI), focuses on optimized implementation of CRT. We offer theoretical and practical strategies to achieve more comprehensive CRT referral and post-procedural care by focusing on four actionable domains: (i) overcoming CRT under-utilization, (ii) better understanding of pre-implant characteristics, (iii) abandoning the term 'non-response' and replacing this by the concept of disease modification, and (iv) implementing a dedicated post-implant CRT care pathway.

The effect of intravenous ferric carboxymaltose on cardiac reverse remodelling following cardiac resynchronization therapy-the IRON-CRT trial

Aims

Iron deficiency is common in heart failure with reduced ejection fraction (HFrEF) and negatively affects cardiac function and structure. The study the effect of ferric carboxymaltose (FCM) on cardiac reverse remodelling and contractile status in HFrEF.

Methods and results

Symptomatic HFrEF patients with iron deficiency and a persistently reduced left ventricular ejection fraction (LVEF <45%) at least 6 months after cardiac resynchronization therapy (CRT) implant were prospectively randomized to FCM or standard of care (SOC) in a double-blind manner. The primary endpoint was the change in LVEF from baseline to 3-month follow-up assessed by three-dimensional echocardiography. Secondary endpoints included the change in left ventricular end-systolic (LVESV) and end-diastolic volume (LVEDV) from baseline to 3-month follow-up. Cardiac performance was evaluated by the force–frequency relationship as assessed by the slope change of the cardiac contractility index (CCI = systolic blood pressure/LVESV index) at 70, 90, and 110 beats of biventricular pacing. A total of 75 patients were randomized to FCM (n = 37) or SOC (n = 38). At baseline, both treatment groups were well matched including baseline LVEF (34 ± 7 vs. 33 ± 8, P = 0.411). After 3 months, the change in LVEF was significantly higher in the FMC group [+4.22%, 95% confidence interval (CI) +3.05%; +5.38%] than in the SOC group (−0.23%, 95% CI −1.44%; +0.97%; P < 0.001). Similarly, LVESV (−9.72 mL, 95% CI −13.5 mL; −5.93 mL vs. −1.83 mL, 95% CI −5.7 mL; 2.1 mL; P = 0.001), but not LVEDV (P = 0.748), improved in the FCM vs. the SOC group. At baseline, both treatment groups demonstrated a negative force–frequency relationship, as defined by a decrease in CCI at higher heart rates (negative slope). FCM resulted in an improvement in the CCI slope during incremental biventricular pacing, with a positive force–frequency relationship at 3 months. Functional status and exercise capacity, as measured by the Kansas City Cardiomyopathy Questionnaire and peak oxygen consumption, were improved by FCM.

Conclusions

Treatment with FCM in HFrEF patients with iron deficiency and persistently reduced LVEF after CRT results in an improvement of cardiac function measured by LVEF, LVESV, and cardiac force–frequency relationship.

Optimized implementation of cardiac resynchronization therapy: a call for action for referral and optimization of care: A joint position statement from the Heart Failure Association (HFA), European Heart Rhythm Association (EHRA), and European Association of Cardiovascular Imaging (EACVI) of the European Society of Cardiology

Cardiac resynchronization therapy (CRT) is one of the most effective therapies for heart failure with reduced ejection fraction and leads to improved quality of life, reductions in heart failure hospitalization rates and all-cause mortality. Nevertheless, up to two-thirds of eligible patients are not referred for CRT. Furthermore, post-implantation follow-up is often fragmented and suboptimal, hampering the potential maximal treatment effect. This joint position statement from three European Society of Cardiology Associations, Heart Failure Association (HFA), European Heart Rhythm Association (EHRA) and European Association of Cardiovascular Imaging (EACVI), focuses on optimized implementation of CRT. We offer theoretical and practical strategies to achieve more comprehensive CRT referral and post-procedural care by focusing on four actionable domains: (i) overcoming CRT under-utilization, (ii) better understanding of pre-implant characteristics, (iii) abandoning the term 'non-response' and replacing this by the concept of disease modification, and (iv) implementing a dedicated post-implant CRT care pathway.

Iron Deficiency Is Associated With Impaired Biventricular Reserve and Reduced Exercise Capacity in Patients With Unexplained Dyspnea

BACKGROUND

Iron deficiency (ID) is frequent and associated with diminished exercise capacity in heart failure (HF), but its contribution to unexplained dyspnea without a HF diagnosis at rest remains unclear.

METHODS AND RESULTS

Consecutive patients with unexplained dyspnea and normal echocardiography and pulmonary function tests at rest underwent prospective standardized cardiopulmonary exercise testing with echocardiography in a tertiary care dyspnea clinic. ID was defined as ferritin of <300 µg/L and a transferrin saturation of <20% and its impact on peak oxygen uptake (peakVO₂), biventricular response to exercise, and peripheral oxygen extraction was assessed. Of 272 patients who underwent cardiopulmonary exercise testing with echocardiography, 63 (23%) had ID. For a similar respiratory exchange ratio, patients with ID had lower peakVO₂ (14.6 ± 7.6 mL/kg/minvs 17.8 ± 8.8 mL/kg/min; P = .009) and maximal workload (89 ± 50 watt vs 108 ± 56 watt P = .047), even after adjustment for the presence of anemia. At rest, patients with ID had a similar left ventricular and right ventricular (RV) contractile function. During exercise, patients with ID had lower cardiac output reserve (P < .05) and depressed RV function by tricuspid s' (P = .004), tricuspid annular plane systolic excursion (P = .034), and RV end-systolic pressure-area ratio (P = .038), with more RV-pulmonary artery uncoupling measured by tricuspid annular plane systolic excursion/systolic pulmonary arterial pressure ratio (P = .023). RV end-systolic pressure-area ratio change from rest to peak exercise, as a load-insensitive metric of RV contractility, was lower in patients with ID (2.09 ± 0.72 mm Hg/cm² vs 2.58 ± 1.14 mm Hg/cm²; P < .001). ID was associated with impaired peripheral oxygen extraction (peakVO₂/peak cardiac output; P = .036). Cardiopulmonary exercise testing with echocardiography resulted in a diagnosis of HF with preserved ejection fraction in 71 patients (26%) based on an exercise E/e' ratio of >14, with equal distribution in patients with (28.6%) or without ID (25.4%, P = .611). None of these findings were influenced in a sensitivity analysis adjusted for a final diagnosis of HFpEF as etiology for the unexplained dyspnea.

CONCLUSIONS

In patients with unexplained dyspnea without clear HF at rest, ID is common and associated with decreased exercise capacity, diminished biventricular contractile reserve, and decreased peripheral oxygen extraction.

Relationship of anemia and clinical outcome in heart failure patients with preserved versus reduced ejection fraction in a rural area of Thailand

Background

Heart failure (HF) has become a significant health burden in developing countries where anemia is highly prevalent. Limited data exists on the effects of anemia on HF in these population.

Methods

A retrospective observational study was conducted in all adult patients hospitalized due to HF at Buriram Hospital in Thailand, during July 2010 to June 2015. Survival analysis was performed to evaluate the impact of anemia on 1- year all-cause mortality for the overall cohort, patients with HF with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF).

Results

A total of 414 HF patients including 287 HFpEF patients (69.3%) and 127 HFrEF patients (30.7%) were included in our analysis. Mean age was 62.51 ± 14.89 years, with 55% female. Overall prevalence of anemia in HF was 62.6% (259 patients). One-year all-cause mortality was significantly higher in patients with anemia than in non-anemia groups (20.08% vs 12.26%, p = 0.041). When analyzed based on types of HF, anemia significantly increased mortality risk in HFpEF group [adjusted hazard ratio (HR) 2.667, 95%CI, 1.216–5.853, p = 0.014] but not with HFrEF group (adjusted HR 0.901, 95%CI, 0.376–2.155, p = 0.804). The mortality of anemic patients who were left untreated was significantly higher than those who were treated (adjusted HR 2.13, 95%CI, 1.13–3.99, p = 0.027).

Conclusion

Anemia significantly increased mortality in HF patients, especially among HFpEF. Attempts to identify, diagnose and manage anemia should be integrated in HF care plan in developing countries with high prevalence of anemia.

Association of iron deficiency, anaemia, and functional outcomes in patients undergoing edge-to-edge mitral valve repair

AIMS

Patients undergoing percutaneous mitral valve repair (PMVR) show a substantial heterogeneity of prognostic and symptomatic benefit. Iron deficiency and anaemia are associated with worse outcomes in heart failure patients. We investigated the impact of these comorbidities on functional and clinical outcome after PMVR.

METHODS AND RESULTS

Iron deficiency and anaemia were prospectively assessed in 130 patients undergoing PMVR with MitraClip. Associations with functional outcomes at 6 weeks [6 min walking distance (6MWD), Short-Form-36 physical component score, and Minnesota Living with Heart Failure Questionnaire score, New York Heart Association class] and long-term clinical outcome were examined. Iron deficiency and anaemia were frequent with 52% and 50%, respectively. Patients with anaemia showed significant worse baseline functional measures, whereas patients with iron deficiency showed only a trend for lower baseline 6MWD. The benefit in functional outcomes after PMVR was notable and did not differ significantly by iron deficiency or anaemia status (range of median changes in 6MWD 35 to 45 m, physical component score 5.6 to 7.2, Minnesota Living with Heart Failure Questionnaire -8.0 to -10.5; improvement of ≥1 New York Heart Association class 69% to 80%). Anaemia was associated with higher risk for the combined endpoint of mortality and heart failure hospitalization (hazard ratio: 2.51; 95% confidence interval: 1.24-5.1; P = 0.01), whereas iron deficiency showed a trend towards more heart failure hospitalizations (hazard ratio: 2.94; 95% confidence interval: 0.94-9.03; P = 0.09).

CONCLUSIONS

The prevalence of iron deficiency and anaemia is high in patients undergoing MitraClip. Clinical baseline status and long-term outcome were worse particularly in patients with anaemia. However, the functional benefit of PMVR was equal in patients with and without iron deficiency and anaemia.

The effect of iron deficiency on cardiac resynchronization therapy: results from the RIDE-CRT Study

Aims

Cardiac resynchronization therapy (CRT) improves functional status, induces reverse left ventricular remodelling, and reduces hospitalization and mortality in patients with symptomatic heart failure, left ventricular systolic dysfunction, and QRS prolongation. However, the impact of iron deficiency on CRT response remains largely unclear. The purpose of the study was to assess the effect of functional and absolute iron deficiency on reverse cardiac remodelling, clinical response, and outcome after CRT implantation.

Methods and results

The relation of iron deficiency and cardiac resynchronization therapy response (RIDE‐CRT) study is a prospective observational study. We enrolled 77 consecutive CRT recipients (mean age 71.3 ± 10.2 years) with short‐term follow‐up of 3.3 ± 1.9 months and long‐term follow‐up of 13.0 ± 3.2 months. Primary endpoints were reverse cardiac remodelling on echocardiography and clinical CRT response, assessed by change in New York Heart Association classification. Echocardiographic CRT response was defined as relative improvement of left ventricular ejection fraction ≥ 20% or left ventricular global longitudinal strain ≥ 20%. Secondary endpoints were hospitalization for heart failure and all‐cause mortality (mean follow‐up of 29.0 ± 8.4 months). At multivariate analysis, iron deficiency was identified as independent predictor of echocardiographic (hazard ratio 4.97; 95% confidence interval 1.15–21.51; P = 0.03) and clinical non‐response to CRT (hazard ratio 4.79; 95% confidence interval 1.30–17.72, P = 0.02). We found a significant linear‐by‐linear association between CRT response and type of iron deficiency (P = 0.004 for left ventricular ejection fraction improvement, P = 0.02 for left ventricular global longitudinal strain improvement, and P = 0.003 for New York Heart Association response). Iron deficiency was also significantly associated with an increase in all‐cause mortality (P = 0.045) but not with heart failure hospitalization.

Conclusions

Iron deficiency is a negative predictor of effective CRT therapy as assessed by reverse cardiac remodelling and clinical response. Assessment of iron substitution might be a relevant treatment target to increase CRT response and outcome in chronic heart failure patients.

Association Between Norepinephrine Levels and Abnormal Iron Status in Patients With Chronic Heart Failure: Is Iron Deficiency More Than a Comorbidity?

Background

Mechanisms underlying iron homeostasis dysregulation in patients with chronic heart failure remain unsettled. In cardiomyocyte models, norepinephrine may lead to intracellular iron depletion, but the potential association between catecholamines (sympathetic activation markers) and iron metabolism biomarkers in chronic heart failure is unknown.

Methods and Results

In this cross‐sectional analysis, we studied the association between plasma norepinephrine levels and serum iron status biomarkers indicating iron storage (ferritin), iron transport (transferrin saturation), and iron demand (soluble transferrin receptor) in a prospective cohort of 742 chronic heart failure patients (mean age, 72±11 years; 56% male). Impaired iron status was defined as ferritin <100 μg/L or transferrin saturation <20%. Impaired iron status was observed in 69% of patients. In multivariate models, greater norepinephrine levels were associated with impaired iron transport (transferrin saturation <20%, odds ratio=2.28; 95% CI [1.19–4.35]; P=0.013), but not with impaired iron storage (ferritin <100 μg/L, odds ratio=1.25; 95% CI [0.73–2.16]; P=0.415). Norepinephrine was a significant predictor of increased iron demand (soluble transferrin receptor, standardized β‐coefficient=0.12; P=0.006) and low transferrin saturation (standardized β‐coefficient=−0.12; P=0.003). However, norepinephrine levels were not associated with iron or ferritin levels (P>0.05). Adjusted norepinephrine marginal means were significantly higher in patients with impaired iron status compared with those with normal iron status (528 pg/mL [505–551] versus 482 pg/mL [448–518], respectively; P=0.038).

Conclusions

In chronic heart failure patients, increased sympathetic activation estimated with norepinephrine levels is associated with impaired iron status and, particularly, dysregulation of biomarkers suggesting impaired iron transport and increased iron demand. Whether the relationship between norepinephrine and iron metabolism is bidirectional and entails causality need to be elucidated in future research.

Iron Deficiency in Acute Decompensated Heart Failure

The aim of this study was to characterize iron deficiency (ID) in acutely decompensated heart failure (ADHF) and identify whether ID is associated with dyspnea class, length of stay (LOS), biomarker levels, and echocardiographic indices of diastolic function in patients with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF). Consecutive patients admitted with ADHF at a single tertiary center were included. Demographic information, pathology investigations, and metrics regarding hospital stay and readmission were recorded. Patients were classified as having 'absolute' ID if they had a ferritin level <100 ng/mL; or 'functional' ID if they had a ferritin 100-200 ng/mL and a transferrin saturation <20%. Of 503 patients that were recruited, 270 (55%) had HFpEF, 160 (33%) had HFREF, and 57 (12%) had heart failure with mid-range ejection fraction. ID was present in 54% of patients with HFrEF and 56% of patients with HFpEF. In the HFpEF group, ID was associated with a LOS of 11 ± 7.7 vs. 9 ± 6 days in iron replete patients, p = 0.036, and remained an independent predictor of increased LOS in a multivariate linear regression incorporating comorbidities, age, and ID status. This study corroborates a high prevalence of ID in both HFrEF and HFpEF, and further shows that in patients with HFpEF there is a prolongation of LOS not seen in HFrEF which may indicate a more prominent role for ID in HFpEF.

Rationale and design of the IRON-CRT trial: effect of intravenous ferric carboxymaltose on reverse remodelling following cardiac resynchronization therapy

AIMS

Iron deficiency is common in heart failure with reduced ejection fraction (HFrEF). In patients with cardiac resynchronization therapy (CRT), it is associated with a diminished reverse remodelling response and poor functional improvement. The latter is partially related to a loss in contractile force at higher heart rates (negative force-frequency relationship).

METHODS AND RESULTS

The effect of intravenous ferric carboxymaltose on reverse remodelling following cardiac resynchronization therapy (IRON-CRT) trial is a multicentre, prospective, randomized, double-blind controlled trial in HFrEF patients who experienced incomplete reverse remodelling (defined as a left ventricular ejection fraction below <45%) at least 6 months after CRT. Additionally, patients need to have iron deficiency defined as a ferritin below 100 μg/L irrespective of transferrin saturation or a ferritin between 100 and 300 μg/L with a transferrin saturation <20%. Patients will be randomized to either intravenous ferric carboxymaltose (dose based according to Summary of Product Characteristics) or intravenous placebo. The primary objective is to evaluate the effect of ferric carboxymaltose on metrics of cardiac reverse remodelling and contractility, measured by the primary endpoint, change in left ventricular ejection fraction assessed by three-dimensional (3D) echo from baseline to 3 month follow-up and the secondary endpoints change in left ventricular end-systolic and end-diastolic volume. The secondary objective is to determine if ferric carboxymaltose is capable of improving cardiac contractility in vivo, by assessing the force-frequency relationship through incremental biventricular pacing. A total of 100 patients will be randomized in a 1:1 fashion.

CONCLUSIONS

The IRON-CRT trial will determine the effect of ferric carboxymaltose on cardiac reverse remodelling and rate-dependent cardiac contractility in HFrEF patients.

CRT Optimization: What Is New? What Is Necessary?

Cardiac resynchronization therapy (CRT) has proven to improve quality of life, reduce heart failure hospitalization, and prolong life in selected heart failure patients with reduced ejection fraction, on optimal medical therapy and with electrical dyssynchrony. To ensure maximal benefit for CRT patients, optimization of care should be implemented. This begins with appropriate referring as well as selecting patients, knowing that the presence of left bundle branch block and QRS ≥ 150 ms is associated with the greatest reverse remodeling. The LV lead, preferably quadripolar, is best targeted in a postero-lateral position. After implantation, optimal device programming should aim for maximal biventricular pacing and in selected cases further electrical delay optimization might be of use. Even as important, is the implementation of thorough multidisciplinary heart failure care with medication uptitration, remote monitoring, rehabilitation, and patient education. The role of newer pacing strategies as endocardial or His-bundle pacing remains the subject of ongoing investigation.

Iron deficiency in heart failure with preserved ejection fraction: a systematic review and meta-analysis

Objective

Iron deficiency (ID) has an established impact on outcomes in patients with heart failure with reduced ejection fraction; however, there is a lack of conclusive evidence in patients with heart failure with preserved ejection fraction (HFpEF). We sought to clarify the prevalence and impact of ID in patients with HFpEF.

Methods

A systematic search of Cohcrane, MEDLINE, EMBASE, Web of Science and CINAHL electronic databases was performed to identify relevant studies. Included studies defined HFpEF as heart failure with an ejection fraction ≥50%. We used a random-effects meta-analysis to determine the composite prevalence of ID in patients with HFpEF across the included studies. Other outcomes were assessed with qualitative analysis due to a paucity of studies with comparable outcome measures.

Results

The prevalence of ID in the included studies was 59% (95% CI 52% to 65%). ID was associated with lower VO₂ max in three of four studies reporting VO₂ max as an outcome measure, lower functional status as determined by dyspnoea class or 6 min walk test in two of three studies, and worse health-related quality of life in both studies reporting on this outcome. Conversely, ID had no impact on death or hospitalisation in three of the four studies investigating this.

Conclusions

ID is highly prevalent in patients with HFpEF and is associated with worse exercise capacity and functional outcomes, but not hospitalisation or mortality. Our study establishes that ID may play an important a role in HFpEF.

Prevalence of underlying gastrointestinal malignancies in iron-deficient heart failure

Aims

Anaemia and iron deficiency (ferritin level < 100 or 100–300 μg/L with transferrin saturation < 20%) are prevalent in heart failure. Mechanistically, iron deficiency is linked to poor intestinal uptake, increased intestinal loss, and chronic inflammation. However, the prevalence of underlying gastrointestinal malignancies is not established in iron‐deficient heart failure with or without anaemia.

Methods and results

Patients followed up in a single‐centre, heart failure database with baseline registration of haemoglobin and iron status were retrospectively evaluated. The proportion of patients undergoing upper and lower gastrointestinal endoscopy between inclusion and censoring was determined. Afterwards, the prevalence of biopsy that confirmed intestinal malignancies in relation to baseline iron and haemoglobin status was determined. Anaemia was defined as a haemoglobin level <12 g/dL, and iron deficiency according to the aforementioned criteria. Of the 1197 patients in the database, 699 (59%) patients underwent full endoscopic workup over a mean follow‐up of 50 ± 27 months. A total of 50 intestinal malignancies were identified (n = 42, 84%, in iron‐deficient vs. n = 8, 16%, non‐iron‐deficient patients; P < 0.001). The prevalence of intestinal malignancies was non‐statistically different in iron‐deficient patients with anaemia (n = 12/129, 9.3%) or without anaemia (n = 30/287, 10.5%; P = 0.551). The prevalence was much lower in patients without iron deficiency with anaemia (n = 5/83, 6%) or without anaemia (n = 3/200, 1.5%). In patients with iron deficiency but without anaemia (a group in which the role of endoscopic workup is less established), ferritin levels carried an inverse diagnostic capacity in detecting patients with an underlying malignancy (area under the curve = 0.741, P < 0.001). A ferritin level < 56 μg/L had the best acuity, detecting malignancies with a sensitivity of 80% and a specificity of 71%.

Conclusions

Endoscopic evaluation is warranted in heart failure patients with iron‐deficient anaemia given the high prevalence of underlying intestinal malignancies, as advised by gastroenterology guidelines. However, additional research is needed assessing the best approach to patients with iron deficiency without anaemia, given the high occurrence of intestinal malignancies in these patients. A lower ferritin level could potentially help stratify the need for an endoscopic workup in these patients.

Iron deficiency in chronic and acute heart failure: A contemporary review on intertwined conditions

Iron Deficiency (ID) is increasingly recognized as a prevalent comorbid condition in Heart Failure (HF). Despite this, the pathophysiological mechanisms for progressive ID in either chronic or acute HF are still poorly understood. Beyond the traditional factors for iron deficit in the general population, we ought to review the specificities of such paucity in the HF patient, particularly focusing on the interplay between heightened inflammation, overactivity of the sympathetic nervous system and the so-called cardio-renal-anaemia-ID syndrome. Currently, ID constitutes not only an independent prognostic marker but also a novel safe therapeutic target. Particularly, in selected stable HF patients with reduced left ventricular ejection fraction, intravenous (IV) iron improves symptomatic burden and reduces hospitalizations due to worsening HF. On this topic, the main trials of IV iron with either iron sucrose (Toblli et al., FERRIC-HF and IRON-HF) or ferric carboxymaltose (FAIR-HF, CONFIRM-HF and EFFECT-HF) will be summarized and discussed. Finally, we debate the gaps in knowledge of ID in special populations, namely the unreliability of routine plasmatic surrogate markers to assess iron status in acute and advanced HF, the challenging patient with both HF and Chronic Kidney Disease, as well as efficacy and safety concerns in these settings and the potential role of iron correction in cardiac resynchronization therapy candidates.

Echocardiography for the management of patients with biventricular pacing: Possible roles in cardiac resynchronization therapy implementation

Cardiac resynchronization therapy (CRT) is an established therapeutic option for the subset of patients with heart failure (HF), reduced ejection fraction (EF), and dyssynchrony evidenced by electrocardiography. Benefit from CRT has been proven in many clinical trials, yet a sizeable proportion of these patients with wide QRS do not respond to this intervention, despite the updated practice guidelines. Several echocardiographic indices, targeting mechanical rather than electrical dyssynchrony, have been suggested to address this issue, but research so far has not succeeded in providing a single and simple measurement with adequate sensitivity and specificity for identification of responders. While there is still ongoing research in this field, echocardiography proves helpful in other aspects of CRT implementation, such as site selection for left ventricular (LV) lead pacing and optimization of pacing parameters during follow-up visits.

Iron Therapy in Heart Failure: Ready for Primetime?

There is an increasing awareness of the prevalence of iron deficiency (ID) in patients with heart failure (HF) and its contributory role in the morbidity and mortality of HF. It is important to note that many HF patients have ID without being anaemic, hence it is vital to screen for ID even in patients with haemoglobin within the normal laboratory range. This review summarises the pathophysiology and epidemiology of ID in HF before discussing the evidence for iron replacement therapy in HF patients. Finally, it discusses the ongoing large outcome trials evaluating iron replacement in HF.

Bridging the gap between heart failure and the device clinic

INTRODUCTION

While cardiac resynchronization therapy (CRT) is a mainstay in the management of selected patients with chronic systolic dysfunction, many patients are noted to experience less than expected or no benefit at all from the therapy. Multidisciplinary care has been shown to provide benefit in follow up for patients receiving CRT devices. Areas covered: This review will focus on the apparent reasons behind less than optimal outcomes following CRT as well as multidisciplinary approaches to treating patients with CRT devices. The literature review focused mainly on the data behind multidisciplinary care of CRT patients. Expert commentary: A multidisciplinary approach incorporating input from various cardiology backgrounds is an important strategy in ensuring optimal outcomes in patients receiving CRT devices. Breaking down the 'silo' effect amongst cardiac subspecialties is vital in achieving high level multidisciplinary care.