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

Treatment of Iron Deficiency in Heart Failure

PURPOSE OF REVIEW

Heart failure (HF) is commonly associated with iron deficiency (ID), defined as insufficient levels of iron to meet physiological demands. ID's association with anaemia is well understood but it is increasingly recognised as an important comorbidity in HF, even in the absence of anaemia. This review summarises contemporary evidence for the measurement and treatment of ID, in both HFrEF and HFpEF, and specific HF aetiologies, and highlights important gaps in the evidence-base.

RECENT FINDINGS

ID is common among patients with HF and associated with increased morbidity and mortality. Correcting ID in patients with HF can impact upon functional status, exercise tolerance, symptoms, and overall quality of life, irrespective of anaemia status. ID is a modifiable comorbidity in HF. Therefore, recognising and treating ID has emerging therapeutic potential and is important for all clinicians who care for patients with HF to understand the rationale and approach to treatment.

Cardiac contractility modulation in heart failure with reduced ejection fraction treatment

Heart failure with reduced left ventricular ejection fraction (LV EF) (HFrEF) is a significant issue of health care due to increasing indexes of morbidity and mortality. The emergence of a number of drugs and implantable devices for the treatment of HFrEF has allowed improvement of patients’ well-being and prognosis. However, high mortality and recurrent decompensated heart failure remain a substantial issue and stimulate the search for new methods of CHF treatment. Cardiac contractility modulation (CCM) is a method of managing patients with HFrEF. Available data from randomized clinical trials (RCT) indicate the efficacy of CCM in improvement of patients’ well-being and quality of life. The question remains open: what effect does CCM have on LV reverse remodeling? Experimental data and results of observational studies suggest a possibility of reverse remodeling by CCM; however, this has not been confirmed in RCT. Also, it remains unclear how CCM influences the frequency of hospitalizations for decompensated heart failure and the death rate of patients with HFrEF. Results of both RCTs and observational studies have shown a moderate improvement of quality of life associated with CCM. Furthermore, RCTs have not found any increase in LV EF due to the therapy, nor has a meta-analysis of RCTs revealed any improvement of the prognosis associated with CCM.  Further RCTs are needed to evaluate the effect of CCM on reverse remodeling, survival rate, and to determine the place of CCM in the treatment of patients with CHF.

The effect of Intravenous ferric-carboxymaltose on right ventricular function - insights from the IRON-CRT trial

BACKGROUND

Ferric carboxymaltose (FCM) improves left ventricular (LV) function in heart failure with reduced ejection fraction (HFrEF). Yet, the effect of FCM on right ventricular (RV) function remains insufficiently elucidated.

METHODS

This is a predefined analysis of the IRON-CRT trial in which symptomatic HFrEF patients with iron deficiency and reduced LV ejection (LVEF) despite optimal medical therapy and cardiac resynchronization therapy (CRT) underwent 1:1-randomization to FCM or placebo in a double blind fashion. RV function was measured as the change from baseline to 3-month follow-up of RV fractional area change (FAC), TAPSE and RV S', systolic pulmonary artery pressure (SPAP) and its coupling to the RV (TAPSE/SPAP-ratio). The RV-contractile reserve was measured as the change in TAPSE during incremental pacing at 70, 90 and 110 Bpm.

RESULTS

A total of 75 patients underwent randomization and received FCM(n= 37) or placebo(n=38). At baseline 72.5% had RV dysfunction and 70% had RV dilatation. At 3-month follow-up patients receiving FCM had a significant improvement in RV FAC (Placebo=-2.2%[-4.9%-+0.6%] vs FCM=+4.1%[+1.4%-+6.9%], p=0.002) and TAPSE (placebo=-0.19mm[-0.85mm-+0.48mm] vs FCM=+0.98mm[+0.28mm-+1.62mm], p=0.020), but not RV S'. Patients receiving FCM had a numerically lower SPAP (p=0.073) and significant improvement in TAPSE/SPAP-ratio (placebo= +0.002[-0.046-+0.051] vs FCM= +0.097[+0.048-+0.146], p=0.008). At baseline both groups had diminished RV-contractile reserve during incremental pacing, which was attenuated at 3-month follow-up in the FCM group (p=0.004). Patients manifesting more RV function improvement were more likely to exhibit higher degrees of LVEF-improvement (p<0.05 for all).

CONCLUSIONS

Treatment with FCM in HFrEF patients results in an improvement in RV function and structure and improves the RV-contractile reserve.

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.

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 in heart failure

Iron deficiency is a major heart failure co‐morbidity present in about 50% of patients with stable heart failure irrespective of the left ventricular function. Along with compromise of daily activities, it also increases patient morbidity and mortality, which is independent of anaemia. Several trials have established parenteral iron supplementation as an important complimentary therapy to improve patient well‐being and physical performance. Intravenous iron preparations, in the first‐line ferric carboxymaltose, demonstrated in previous clinical trials superior clinical effect in comparison with oral iron preparations, improving New York Heart Association functional class, 6 min walk test distance, peak oxygen consumption, and quality of life in patients with chronic heart failure. Beneficial effect of iron deficiency treatment on morbidity and mortality of heart failure patients is waiting for conformation in ongoing trials. Although the current guidelines for treatment of chronic and acute heart failure acknowledge importance of iron deficiency correction and recommend intravenous iron supplementation for its treatment, iron deficiency remains frequently undertreated and insufficiently diagnosed in setting of the chronic heart failure. This paper highlights the current state of the art in the pathophysiology of iron deficiency, associations with heart failure trajectory and outcome, and an overview of current guideline‐suggested treatment options.

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.

Short-term changes in left and right systolic function following ferric carboxymaltose: a substudy of the Myocardial-IRON trial

AIMS

The mechanisms underlying the beneficial effect of ferric carboxymaltose (FCM) in patients with heart failure (HF) and iron deficiency (ID) have not been completely characterized. The Myocardial-IRON trial was a double-blind, randomized trial that evaluated myocardial iron repletion following FCM vs. placebo in 53 patients with HF and ID. In this post hoc analysis, we evaluated whether treatment with FCM was associated with cardiac magnetic resonance changes in left and right ventricular function (LVEF and RVEF, respectively) at different points of systolic dysfunction.

METHODS AND RESULTS

We included patients from the Myocardial-IRON trial with left and right ventricular systolic dysfunction (LVSD and RVSD, respectively) at enrolment. Linear mixed regression models were used to evaluate changes at 7 and 30 days on LVEF and RVEF at cardiac magnetic resonance. At enrolment, 27 (50.9%) and 38 (71.7%) patients had LVEF < 40% (LVSD1 ) or <45% (LVSD2 ), respectively, and 10 (18.9%) and 17 (32.1%) patients had RVEF < 45% (RVSD1 ) or <51% in women and <52% in men (RVSD2) , respectively. Treatment with FCM was associated with a significant improvement in LVEF at 30 days (LVSD1 : Δ2.3%, P < 0.001; LVSD2 : Δ4.1, P = 0.014). FCM was also associated with a significant and early improvement in RVEF at 7 days (RVSD1 : Δ6.9%, P = 0.003; RVSD2 : Δ3.2%, P = 0.003) that persisted at 30 days (RVSD1 : Δ8.1%, P < 0.001; RVSD2 : Δ4.7%, P < 0.001).

CONCLUSIONS

In patients with HF and systolic dysfunction with ID, FCM was associated with short-term improvement in LVEF and, especially, in RVEF.

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.