Improvement of ejection fraction and mortality in ischaemic heart failure

Myocardial Recovery and Relapse in Heart Failure With Improved Ejection Fraction

Purpose of review

The purpose of this review is to discuss myocardial recovery in heart failure with reduced ejection fraction (HFrEF) and to summarize the contemporary insights regarding heart failure with improved ejection fraction (HFimpEF).

Recent findings

Improvement in left ventricular ejection fraction (LVEF ≥ 40%) with improved prognosis can be achieved in one out of three (10-40%) patients with HFrEF treated with guideline-directed medical therapy. Clinical predictors include non-ischemic etiology of HFrEF, less abnormal blood or imaging biomarkers, and lack of specific pathogenic genetic variants. However, a subset of patients may ultimately relapse, suggesting that many patients are merely in remission rather than having fully recovered.

Summary

Patients with HFimpEF have improved prognosis but nonetheless remain at risk of relapse and long-term adverse events. Future studies will hopefully chart the natural history of HFimpEF and identify clinical predictors such as blood or novel imaging biomarkers that distinguish subgroups of patients based on differential trajectory and prognosis.

Selecting the appropriate patients for coronary artery bypass grafting in ischemic cardiomyopathy-importance of myocardial viability

Patients who undergo coronary artery bypass graft (CABG) surgery in ischemic cardiomyopathy have a survival advantage over medical therapy at 10 years. The survival advantage of CABG over medical therapy is due to its ability to reduce future myocardial infarction, and by conferring electrical stability. The presence of myocardial viability does not provide a differential survival advantage for CABG over medical therapy. Presence of angina and inducible ischemia are also less predictive of outcome. Moreover, CABG is associated with significant early mortality. Hence, careful patient selection is more important for reducing the early mortality and improving the long-term outcome than relying on results of myocardial viability. Younger patients with good exercise tolerance benefit the most, while patients who are frail and patients with renal dysfunction and dysfunctional right ventricle seem to have very high operative mortality. Elderly patients, because of poor life expectancy, do not benefit from CABG, but the age cutoff is not clear. Patients also need to have revascularizable targets, but this decision is often based on experience of the surgical team and heart team discussion. These recommendations are irrespective of the myocardial viability tests. Optimal medical treatment remains the cornerstone for management of ischemic cardiomyopathy.

Heart failure with improved ejection fraction: Beyond diagnosis to trajectory analysis

Left ventricular (LV) systolic dysfunction represents a highly treatable cause of heart failure (HF). A substantial proportion of patients with HF with reduced ejection fraction (EF;HFrEF) demonstrate improvement in LV systolic function (termed HF with improved EF [HFimpEF]), either spontaneously or when treated with guideline-directed medical therapy (GDMT). Although it is a relatively new HF classification, HFimpEF has emerged in recent years as an important and distinct clinical entity. Improvement in LVEF leads to decreased rates of mortality and adverse HF-related outcomes compared to patients with sustained LV systolic dysfunction (HFrEF). While numerous clinical and imaging factors have been associated with HFimpEF, identification of which patients do and do not improve requires further investigation. In addition, patients improve at different rates, and what determines the trajectory of HFimpEF patients after improvement is incompletely characterized. A proportion of patients maintain improvement in LV systolic function, while others experience a recrudescence of systolic dysfunction, especially with GDMT discontinuation. In this review we discuss the contemporary guideline-recommended classification definition of HFimpEF, the epidemiology of improvement in LV systolic function, and the clinical course of this unique patient population. We also offer evidence-based recommendations for the clinical management of HFimpEF and provide a roadmap for future directions in understanding and improving outcomes in the care of patients with HFimpEF.

Parameters associated with improvement of systolic function in patients with heart failure

AIMS

Identifying clinical and echocardiographic parameters associated with improvement in systolic function in outpatients with heart failure with reduced ejection fraction (HFrEF) could lead to more targeted treatment improving systolic function and outcome.

METHODS

In a retrospective cohort study, echocardiographic examinations from the first and final visit of 686 patients with HFrEF at the heart failure clinic at Gentofte Hospital were retrieved and analysed. Parameters associated with left ventricular ejection fraction (LVEF) improvement and survival according to LVEF improvement were assessed using linear regression and Cox regression, respectively. Beta-coefficients (β-coef) are standardised. Strain values are absolute.

RESULTS

While undergoing heart failure treatment, 559 (81.5%) patients improved systolic function ( Δ LVEF >0%), with 100 (14.6%) being super responders defined by LVEF improvement >20%. After multivariable adjustment, LVEF improvement was significantly associated with a less impaired global longitudinal strain (β-coef 0.25, p<0.001), higher tricuspid annular plane systolic excursion (β-coef 0.09, p=0.018), smaller left ventricular internal dimension in diastole (β-coef -0.15, p=0.011), lower E-wave/A-wave ratio (β-coef -0.13, p=0.003), higher heart rate (β-coef 0.18, p<0.001) and absence of ischaemic cardiomyopathy (β-coef -0.11, p=0.010) and diabetes (β-coef -0.081, p=0.033) at baseline. Mortality incidence rates differed with LVEF improvement ( Δ LVEF <0% vs Δ LVEF >0%, 8.3 vs 4.3 per 100 person years, p=0.012). Greater improvement in LVEF was associated with significantly lower mortality risk (tertile 1 vs tertile 3, HR 3.23, 95% CI 1.39 to 7.51, p=0.006).

CONCLUSION

In this outpatient HFrEF cohort, most patients improved systolic function. Heart failure aetiology, comorbidities and echocardiographic measures of heart structure and function were significantly, independently associated with future LVEF improvement. Greater LVEF improvement was significantly associated with lower mortality.

The Evolving Paradigm of Revascularization in Ischemic Cardiomyopathy: from Recovery of Systolic Function to Protection Against Future Ischemic Events

PURPOSE OF REVIEW

We aim to reevaluate how the assessment of myocardial viability can guide optimal treatment strategies for patients with ischemic cardiomyopathy (ICM) based on a more contemporary understanding of the mechanism of benefit of revascularization.

RECENT FINDINGS

The assessment of viability in left ventricular (LV) segments with diminished contraction has been proposed as key to predict the benefit of revascularization and, therefore, as a requisite for the selection of patients to undergo this form of treatment. However, data from prospective trials have diverged from earlier retrospective studies. Traditional binary viability assessment may oversimplify ICM's complexity and the nuances of revascularization benefits. A conceptual shift from the traditional paradigm centered on the assessment of viability as a dichotomous variable to a more comprehensive approach encompassing a thorough understanding of ICM's complex pathophysiology and the salutary effect of revascularization in the prevention of myocardial infarction and ventricular arrhythmias is required.

Sudden Cardiac Death in Ischaemic Cardiomyopathy and the Primary Prevention ICD: Time for a More a Personalised Approach?

Guidelines recommend primary prevention implantable cardioverter defibrillator (PPICD) for left ventricular ejection fraction (LVEF) <35% only after 3 months of optimal medical therapy (OMT) or 6 weeks after acute MI with persistent LVEF dysfunction. A 73-year-old woman presented with decompensated heart failure secondary to ischaemic cardiomyopathy. Severe coronary disease with sufficient dysfunctional myocardial segments on cardiac MRI suggested potential benefit from revascularisation. Following discussion with the heart team, she underwent percutaneous coronary intervention (PCI). PPICD implantation was deferred as per guideline recommendations. However, 20 days post-PCI, the patient died from malignant ventricular arrhythmia captured on a Holter monitor. This case demonstrates that some high-risk patients may not receive a potentially life-saving PPICD if guidelines are stringently adhered to. We highlight evidence that LVEF alone is of limited value in a risk assessment of arrhythmogenic death, and postulate that a more personalised ICD prescription should be considered using scar characteristics on cardiac MRI to prompt upstream ICD implantation in high-risk patients.

Predicting left ventricular functional recovery in ischaemic cardiomyopathy: needs and challenges

Left ventricular (LV) systolic function is an essential parameter for the evaluation of patients with ischaemic heart disease, and therapeutic choices are significantly driven by LV ejection fraction (LVEF) in the early stage of the disease and during follow-up. After an acute coronary syndrome, ventricular dysfunction may be reversible when caused by transient myocardial stunning. Therefore, the identification of clinical, laboratory, and instrumental predictors of improvement in LV systolic function (in addition to LVEF) is essential for an adequate prognostic stratification. In the setting of chronic ischaemic heart disease, there is no evidence that an improvement in LV systolic function is invariably associated with a better prognosis and LVEF is only one of many parameters that should be considered for the risk stratification. This state-of-the-art review will critically analyse the scientific evidence regarding known predictors of LVEF recovery, trying to elucidate their pathophysiological principles and clinical value.

Determinants of ejection fraction improvement in heart failure patients with reduced ejection fraction

AIMS

This study aimed to investigate the prognostic value of dynamic changes in left ventricular ejection fraction (EF) for cardiovascular (CV) outcomes in an all-comer heart failure (HF) population with reduced EF (HFrEF, EF < 40%). We sought to identify independent factors related to improvement in EF and to identify risk factors for increased risk of CV events in the subgroups of improved EF (iEF) and non-improved EF (niEF), respecively.

METHODS AND RESULTS

This is a retrospective sub-analysis from the REDEAL HF trial, which included consecutive patients with chronic HF who were hospitalized from July 2009 to December 2017. Baseline and follow-up echocardiography data (interval ≥12 months) of 573 consecutive patients with HFrEF were analysed. iEF was defined as absolute improvement in EF ≥ 10% and follow-up EF over 40%. The primary endpoint was defined as a composite endpoint of cardiovascular (CV) death, CV hospitalization, or appropriate implantable cardioverter-defibrillator (ICD) therapy for ventricular arrhythmia. EF improved in 37.2% of patients with HFrEF during follow-up (median period of 17 months). iEF was independently associated with shorter HF duration (>4 vs. ≤4 years, odd ratio [OR] = 0.477, 95% CI 0.305-0.745), no coronary artery disease (CAD vs. no CAD, OR = 0.583, 95% CI 0.396-0.858), and no ICD implantation (ICD vs. no ICD, OR = 0.341, 95% CI 0.228-0.511). Compared with niEF, iEF was significantly and independently associated with lower all-cause mortality (22.1% vs. 31.1%, P = 0.019; hazard ratio [HR] = 0.674, 95% CI 0.469-0.968), lower CV mortality (8.9% vs. 16.1%, P = 0.015; HR = 0.539, 95% CI 0.317-0.916), and lower CV events risk (27.2% vs. 49.2%, P < 0.001; HR 0.519, 95% CI 0.381-0.708), after adjustment for age, sex, duration of HF, and other clinical risk factors. Hypertension (HR = 2.452, P = 0.032) and elevated N-terminal prohormone of brain natriuretic peptide (NT-proBNP >1153 pg/mL, HR = 4.372, P < 0.001) were identified as independent risk factors for CV events in the iEF subgroup. ICD implantation (HR = 1.533, P = 0.011), elevated NT-proBNP (HR = 1.626, P = 0.018), increased left atrial volume index (HR = 1.461, P = 0.021), reduced lateral mitral annular plane systolic excursion (HR = 1.478, P = 0.025), and reduced tricuspid plane systolic excursion (HR = 1.491, P = 0.039) were identified as risk factors for CV events in the niEF subgroup.

CONCLUSIONS

Improvement in EF is independently related to the longer survival and lower CV related mortality and hospitalization rate of HFrEF. Elevated baseline NT-proBNP is identified as the strongest prognostic factor associated with increased CV events risk in HFrEF patients both with and without improved EF, regardless of age, sex, duration of HF, and other clinical risk factors.

Perioperative changes in left ventricular systolic function following surgical revascularization

Background

Nearly 1/3^rd of patients undergoing coronary artery bypass graft surgery (CABG) have left ventricular systolic dysfunction. However, the extent, direction and implications of perioperative changes in left ventricular ejection fraction (LVEF) have not been well characterized in these patients.

Methods

We studied the changes in LVEF among 549 patients with left ventricular systolic dysfunction (LVEF <50%) who underwent CABG as part of the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Patients had pre- and post-CABG (4 month) LVEF assessments using identical cardiac imaging modality, interpreted at a core laboratory. An absolute change of >10% in LVEF was considered clinically significant.

Results

Of the 549 patients (mean age 61.4±9.55 years, and 72 [13.1%] women), 145 (26.4%) had a >10% improvement in LVEF, 369 (67.2%) had no change and 35 (6.4%) had >10% worsening of LVEF following CABG. Patients with lower preoperative LVEF were more likely to experience an improvement after CABG (odds ratio 1.36; 95% CI 1.21–1.53; per 5% lower preoperative LVEF; p <0.001). Notably, incidence of postoperative improvement in LVEF was not influenced by presence, nor absence, of myocardial viability (25.5% vs. 28.3% respectively, p = 0.67). After adjusting for age, sex, baseline LVEF, and NYHA Class, a >10% improvement in LVEF after CABG was associated with a 57% lower risk of all-cause mortality (HR: 0.43, 95% CI: 0.26–0.71).

Conclusions

Among patients with ischemic cardiomyopathy undergoing CABG, 26.4% had >10% improvement in LVEF. An improvement in LVEF was more likely in patients with lower preoperative LVEF and was associated with improved long-term survival.

Effect of metformin on left ventricular mass and functional parameters in non-diabetic patients: a meta-analysis of randomized clinical trials

Background

Left ventricular hypertrophy is a common finding in patients with ischemic heart disease and is associated with mortality in patients with cardiovascular disease (CVD). Metformin, an antidiabetic drug, has been shown to reduce oxidative stress and left ventricular mass index (LVMI) in animal hypertrophy models. We summarized evidence regarding the effect of metformin on LVMI and LVEF.

Methods

Electronic databases were searched for randomized clinical trials (RCTs) that used metformin in non-diabetic patients with or without pre-existing CVD. The standardized mean change using change score standardization (SMCC) was calculated for each study. The random-effects model was used to pool the SMCC across studies. Meta-regression analysis was used to assess the association of heart failure (HF), metformin dose, and duration with the SMCC.

Results

Data synthesis from nine RCTs (754 patients) showed that metformin use resulted in higher reduction in LVMI after 12 months (SMCC = −0.63, 95% CI − 1.23; − 0.04, p = 0.04) and an overall higher reduction in LVMI (SMCC = −0.5, 95% CI − 0.84; − 0.16, p < 0.01). These values equate to absolute values of 11.3 (95% CI 22.1–0.72) and 8.97 (95% CI 15.06–2.87) g/m², respectively. The overall improvement in LVEF was also higher in metformin users after excluding one outlier (SMCC = 0.26, 95% CI 0.03–0.49, P = 0.03) which translates to a higher absolute improvement of 2.99% (95% CI 0.34; 5.63). Subgroup analysis revealed a favorable effect for metformin on LVEF in patients who received > 1000 mg/day (SMCC = 0.28, 95% CI 0.04; 0.52, P = 0.04), and patients with HF (SMCC = 0.23; 95% CI 0.1; 0.36; P = 0.004). These values translate to a higher increase of 2.64% and 3.21%, respectively.

Conclusion

Results suggest a favorable effect for metformin on LVMI and LVEF in patients with or without pre-existing CVD. Additional trials are needed to address the long-term effect of metformin.

Registration The study was registered on the PROSPERO database with the registration number CRD42021239368 (https://www.crd.york.ac.uk/prospero).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02845-w.

Metformin therapy regresses LVH by approximately 10 g/m² in non-diabetic patients after 12 months of use (SMCC = −0.63, 95% CI − 1.23; − 0.04, p = 0.04).

Metformin therapy was associated with a modest (2–3%) but greater overall improvement in LVEF.

Higher dose (> 1000 mg/day) and longer treatment duration were associated with a significant effect for metformin on LVMI and LVEF.

Metformin use in HF patients was associated with an absolute increase of 3.21% in LVEF (SMCC = 0.23; 95% CI 0.1; 0.36, P = 0.004).

Ischemic Cardiomyopathy and Heart Failure After Acute Myocardial Infarction

Purpose of Review

Ischemic cardiomyopathy refers to systolic left ventricular dysfunction in the setting of obstructive coronary artery disease and represents the most common cause of heart failure worldwide. It is often the combination of an irreversible loss of viable mass following an acute myocardial infarction (AMI) with a dysfunctional, but still viable, myocardium in the context of a chronically reduced myocardial blood flow and reduced coronary reserve. Medical treatments aiming at modulating neurohumoral response and restoring blood flow to the ischemic cardiomyocytes were shown to dramatically abate the occurrence of ventricular dysfunction and adverse remodeling in ischemic cardiomyopathy.

Recent Findings

Novel therapeutic approaches, such as mechanical unloading and modulation of the inflammatory response, appear to be promising. Furthermore, the understanding of the mechanisms by which, despite optimal treatment, heart failure ensues after AMI, with or without adverse remodeling and systolic dysfunction, is a critical step in the search for novel ways to tackle heart failure risk beyond preservation of left ventricular volumes and systolic function.

Summary

In this review article, we explore the principal pathophysiological mechanisms and pathways of heart failure in ischemic cardiomyopathy, therapeutic opportunities, and knowledge gaps in this area.

A Cardiac Surgeon's Viewpoint of Myocardial Viability in the Era of Multimodality Imaging

The relationship between myocardial viability and the benefit of revascularization has been tested in observational studies and prospective trials, with conflicting results. Despite the controversies, viability imaging to guide decision-making with respect to surgical revascularization in ischemic cardiomyopathy remains a valid concept. We present a modern paradigm for viability testing which centers around myocardial protection rather than improvement of contractility.

Myocardial viability testing: all STICHed up, or about to be REVIVED?

Patients with ischaemic left ventricular dysfunction frequently undergo myocardial viability testing. The historical model presumes that those who have extensive areas of dysfunctional-yet-viable myocardium derive particular benefit from revascularization, whilst those without extensive viability do not. These suppositions rely on the theory of hibernation and are based on data of low quality: taking a dogmatic approach may therefore lead to patients being refused appropriate, prognostically important treatment. Recent data from a sub-study of the randomized STICH trial challenges these historical concepts, as the volume of viable myocardium failed to predict the effectiveness of coronary artery bypass grafting. Should the Heart Team now abandon viability testing, or are new paradigms needed in the way we interpret viability? This state-of-the-art review critically examines the evidence base for viability testing, focusing in particular on the presumed interactions between viability, functional recovery, revascularization and prognosis which underly the traditional model. We consider whether viability should relate solely to dysfunctional myocardium or be considered more broadly and explore wider uses of viability testingoutside of revascularization decision-making. Finally, we look forward to ongoing and future randomized trials, which will shape evidence-based clinical practice in the future.

A Universal New Definition of Heart Failure With Improved Ejection Fraction for Patients With Coronary Artery Disease

Aims: The aims of this study were to describe the characteristics and outcomes of the universal new definition of heart failure with improved ejection fraction (HFimpEF) and to identify predictors for HFimpEF among patients with coronary artery disease (CAD).

Methods: CAD subjects with heart failure with reduced ejection fraction (HFrEF) (EF ≤ 40%) at baseline were enrolled from the real-world registry of the Cardiorenal ImprovemeNt study from January 2007 to December 2018. The new definition of HFimpEF was defined as left ventricular EF (LVEF) of≤40% at baseline and with improvement of up to 40% and at least a ≥ 10% increase during 1 month to 1 year after discharge.

Results: Of the 747 CAD patients with HFrEF (86.7% males, mean age: 61.4 ± 11 years), 267 (35.7%) patients conformed to the new HFimpEF definition. Patients with HFimpEF were younger (adjusted odds ratio [aOR]: 0.98 [0.97–0.99]) and had a higher rate of hypertension (aOR:1.43 [1.04–1.98]), lower rate of percutaneous coronary intervention (PCI) treatment at the time of detection of HFrEF (aOR: 0.48 [0.34–0.69]), history of PCI (aOR: 0.51 [0.28–0.88]), history of acute myocardial infarction (aOR: 0.40 [0.21–0.70]), and lower left ventricular end diastolic diameter (aOR: 0.92 [0.90–0.95]). During 3.3-year follow-up, patients with HFimpEF demonstrated lower rates of long-term all-cause mortality (13.1% vs. 20.8%, aHR: 0.61[0.41–0.90]).

Conclusion: In our study, CAD patients with HFimpEF achieved a better prognosis compared to those with persistent HFrEF. Patients with CAD meeting the criteria for the universal definition of HFimpEF tended to be younger, presented fewer clinical comorbidities, and had lower left ventricular end diastolic diameter.

Prevalence and Prognosis of HFimpEF Developed From Patients With Heart Failure With Reduced Ejection Fraction: Systematic Review and Meta-Analysis

Background: Heart failure with improved ejection fraction (HFimpEF) is classified as a new type of heart failure, and its prevalence and prognosis are not consistent in previous studies. There is no systematic review and meta-analysis regarding the prevalence and prognosis of the HFimpEF.

Method: A systematic search was performed in MEDLINE, EMBASE, and Cochrane Library from inception to May 22, 2021 (PROSPERO registration: CRD42021260422). Studies were included for analysis if the prognosis of mortality or hospitalization were reported in HFimpEF or in patients with heart failure with recovered ejection fraction (HFrecEF). The primary outcome was all-cause mortality. Cardiac hospitalization, all-cause hospitalization, and composite events of mortality and hospitalization were considered as secondary outcomes.

Result: Nine studies consisting of 9,491 heart failure patients were eventually included. During an average follow-up of 3.8 years, the pooled prevalence of HFimpEF was 22.64%. HFimpEF had a lower risk of mortality compared with heart failure patients with reduced ejection fraction (HFrEF) (adjusted HR: 0.44, 95% CI: 0.33–0.60). HFimpEF was also associated with a lower risk of cardiac hospitalization (HR: 0.40, 95% CI: 0.20–0.82) and the composite endpoint of mortality and hospitalization (HR: 0.56, 95% CI: 0.44–0.73). Compared with patients with preserved ejection fraction (HFpEF), HFimpEF was associated with a moderately lower risk of mortality (HR: 0.42, 95% CI: 0.32–0.55) and hospitalization (HR: 0.73, 95% CI: 0.58–0.92).

Conclusion: Around 22.64% of patients with HFrEF would be treated to become HFimpEF, who would then obtain a 56% decrease in mortality risk. Meanwhile, HFimpEF is associated with lower heart failure hospitalization. Further studies are required to explore how to promote left ventricular ejection fraction improvement and improve the prognosis of persistent HFrEF in patients.

Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021260422, identifier: CRD42021260422.

Association of early versus delayed normalisation of left ventricular ejection fraction with mortality in ischemic cardiomyopathy

Objective

In patients with non-ischaemic cardiomyopathy and reduced left ventricular ejection fraction (LVEF), normalisation of LVEF is associated with improved outcomes. However, data on patients with ischaemic cardiomyopathy and recovered LVEF are lacking. The goal of this study was to assess the prognostic significance of normalisation of the LVEF in patients with ischaemic cardiomyopathy.

Methods/Results

We performed a non-prespecified post hoc analysis of the Surgical Treatment for Ischaemic Heart Failure (STICH) trial to determine the association between normalisation of LVEF (>50%) and mortality during follow-up. Of the 1212 patients with LVEF <35% enroled in the STICH trial, 932 underwent assessment of LVEF at 4 months and/or 2 years after enrolment. Among them, 18 patients experienced normalisation in LVEF at 4-month follow-up and 35 patients experienced recovery in LVEF at 2 years. Recovery of LVEF at 4 months and recovery of LVEF at 2 years were not correlated. Recovery of LVEF at 4 months was not associated with reduced all-cause mortality in unadjusted analysis (log-rank test p=0.54) or in Cox proportional hazards analysis (HR: 0.93; 95% CI: 0.48 to 1.80; p=0.82). Ejection fraction recovery at 2 years was associated with a reduction in all-cause mortality, both in unadjusted analysis (log-rank test p=0.004) and in the Cox proportional hazard model (HR: 0.41; 95% CI: 0.21 to 0.80; p=0.009).

Conclusions

In patients with ischaemic cardiomyopathy, delayed normalisation of LVEF is associated with reduced mortality, whereas early recovery of LVEF is not. Further studies are needed to confirm these findings.