Mechanisms for heart failure in systemic right ventricle

Contemporary treatment of right ventricular failure

Right ventricular failure (RVF) is a clinical syndrome resulting from structural and functional changes in the right ventricle (RV), leading to inadequate blood flow to the pulmonary circulation and elevated systemic venous pressures. Factors modulating RV function include afterload, preload, contractility, and interventricular dependency. The pathophysiology of RVF involves complex interactions, such as maladaptive hypertrophy, metabolic reprogramming, inflammation, fibrosis, apoptosis, and endothelial dysfunction. Therapeutic strategies are limited for RVF, as basic and clinical research has historically focused mainly on the left ventricle. Novel pharmacological interventions targeting metabolism, calcium homeostasis, oxidative stress, extracellular matrix remodeling, endothelial function, and inflammation are needed to address RVF effectively. This review explores the etiology, mechanisms, and pathophysiology of RVF, drugs directly targeting the RV myocardium, the intricate biological processes between RV and pulmonary vascular remodeling, surgical and device therapies, and future perspectives on managing RVF.

Right Ventricular Remodeling in Complex Congenital Heart Disease

In congenital heart diseases (CHDs) of moderate to great complexity involving the right ventricle (RV), the morphologic RV can be exposed to significant stressors across the lifespan, either in a biventricular circulation in a subpulmonary or subaortic position or as part of a univentricular circulation. These include pressure and/or volume overload, hypoxia, ischemia, and periprocedural surgical stress, leading to remodeling, maladaptation, dilation, hypertrophy, and dysfunction. In this review we examine the macroscopic remodeling of the RV in various forms of CHD and explore remodeling trajectories, along with the effects of surgeries and residual lesion repair, in tetralogy of Fallot, Ebstein anomaly, congenitally corrected transposition of the great arteries, transposition of the great arteries with atrial switch surgery, and single ventricle palliated by Fontan. In addition, the role of metabolism, genetic markers, and imaging criteria of RV remodeling are explored. Finally, the optimal timing for addressing residual lesions in CHD through surgery or percutaneous interventions is discussed, along with advanced heart failure management strategies and medical therapy aimed at preventing further RV dilation and/or systolic deterioration or promoting reverse remodeling.

Propensity Score Analysis of Possible Medication Effects on Outcomes in Patients With Systemic Right Ventricles

Background

Patients with systemic right ventricle (SRV), either d-transposition of the great arteries following an atrial switch procedure or congenitally corrected transposition of the great arteries, develop severe right ventricular dysfunction, prompting appropriate medical therapy. However, the efficacy of beta-blockers and angiotensin receptor blockers or angiotensin-converting enzyme inhibitors (ACEI) in SRV patients is unproven.

Objectives

The objective of this study was to determine the effects of ACEI/ARB and beta-blockers on outcomes in SRV patients after accounting for likely cofounders affecting their use.

Methods

From a retrospective, multicenter study on heart failure-related outcome in individuals with SRV, those who were taking an ACEI/ARB, beta-blocker, or both of these medication were identified. We performed a propensity analysis to match them to those not using these medications at their initial visit. Matching was based on a propensity score, which captured co-morbidities, demographics, and baseline echocardiographic parameters. Primary outcome of death, transplant, or mechanical circulatory support, and secondary outcomes of heart failure hospitalizations/atrial arrhythmias were analyzed respectively.

Results

We identified 393 patients taking ACEI/ARB or beta-blocker, or taking both a beta-blocker and ACEI/ARB (62.1% male, median age 31.3 years) and 484 patients (56.4% male, median age of 26.0 years) who were neither on a beta-blocker nor on ACEI/ARB at the time of initial clinic visit. Median follow-up was ∼8 years. After propensity matching, medication use was not associated with decreased mortality, heart failure hospitalizations, or arrhythmias. Hazard ratios remained positive for beta blockers, implying potential harm rather than benefit.

Conclusions

In this large multicenter propensity-matched observational study, patients with SRV taking beta-blockers or ACEI/ARB did not have a benefit in survival or reduced hospitalization. The likelihood of demonstrating favorable effects in larger studies appears remote.

Pathogenesis and Surgical Treatment of Dextro-Transposition of the Great Arteries (D-TGA): Part II

Dextro-transposition of the great arteries (D-TGA) is the second most common cyanotic heart disease, accounting for 5-7% of all congenital heart defects (CHDs). It is characterized by ventriculoarterial (VA) connection discordance, atrioventricular (AV) concordance, and a parallel relationship with D-TGA. As a result, the pulmonary and systemic circulations are separated [the morphological right ventricle (RV) is connected to the aorta and the morphological left ventricle (LV) is connected to the pulmonary artery]. This anomaly is included in the group of developmental disorders of embryonic heart conotruncal irregularities, and their pathogenesis is multifactorial. The anomaly's development is influenced by genetic, epigenetic, and environmental factors. It can occur either as an isolated anomaly, or in association with other cardiac defects. The typical concomitant cardiac anomalies that may occur in patients with D-TGA include ventriculoseptal defects, patent ductus arteriosus, left ventricular outflow tract obstruction (LVOTO), mitral and tricuspid valve abnormalities, and coronary artery variations. Correction of the defect during infancy is the preferred treatment for D-TGA. Balloon atrial septostomy (BAS) is necessary prior to the operation. The recommended surgical correction methods include arterial switch operation (ASO) and atrial switch operation (AtrSR), as well as the Rastelli and Nikaidoh procedures. The most common postoperative complications include coronary artery stenosis, neoaortic root dilation, neoaortic insufficiency and neopulmonic stenosis, right ventricular (RV) outflow tract obstruction (RVOTO), left ventricular (LV) dysfunction, arrhythmias, and heart failure. Early diagnosis and treatment of D-TGA is paramount to the prognosis of the patient. Improved surgical techniques have made it possible for patients with D-TGA to survive into adulthood.

Clinical Factors Affecting Survival in Patients with Congenitally Corrected Transposition of the Great Arteries: A Systematic Review and Meta-Analysis

Background: Congenitally corrected transposition of the great arteries (cc-TGA) is a defect characterized by arterio-ventricular and atrioventricular disconcordance. Most patients have co-existing cardiac abnormalities that warrant further treatment. Some patients do not require surgical intervention, but most undergo physiological repair or anatomical surgery, which enables them to reach adulthood. Aims: We aimed to evaluate mortality risk factors in patients with cc-TGA. Results: We searched the PubMed database and included 10 retrospective cohort studies with at least a 5-year follow-up time with an end-point of cardiovascular death a minimum of 30 days after surgery. We enrolled 532 patients, and 83 met the end-point of cardiovascular death or equivalent event. As a risk factor for long-term mortality, we identified New York Heart Association (NYHA) class ≥III/heart failure hospitalization (OR = 10.53; 95% CI, 3.17-34.98) and systemic ventricle dysfunction (SVD; OR = 4.95; 95% CI, 2.55-9.64). We did not show history of supraventricular arrhythmia (OR = 2.78; 95% CI, 0.94-8.24), systemic valve regurgitation ≥moderate (SVR; OR = 4.02; 95% Cl, 0.84-19.18), and pacemaker implantation (OR = 1.48; 95% Cl, 0.12-18.82) to affect the long-term survival. In operated patients only, SVD (OR = 4.69; 95% CI, 2.06-10.71) and SVR (OR = 3.85; 95% CI, 1.5-9.85) showed a statistically significant impact on survival. Conclusions: The risk factors for long-term mortality for the entire cc-TGA population are NYHA class ≥III/heart failure hospitalization and systemic ventricle dysfunction. In operated patients, systemic ventricle dysfunction and at least moderate systemic valve regurgitation were found to affect survival.

External Validation of a Risk Score Model for Predicting Major Clinical Events in Adults After Atrial Switch

BACKGROUND

A risk model has been proposed to provide a patient individualized estimation of risk for major clinical events (heart failure events, ventricular arrhythmia, all-cause mortality) in patients with transposition of the great arteries and atrial switch surgery. We aimed to externally validate the model.

METHODS AND RESULTS

A retrospective, multicentric, longitudinal cohort of 417 patients with transposition of the great arteries (median age, 24 years at baseline [interquartile range, 18-30]; 63% men) independent of the model development and internal validation cohort was studied. The performance of the prediction model in predicting risk at 5 years was assessed, and additional predictors of major clinical events were evaluated separately in our cohort. Twenty-five patients (5.9%) met the major clinical events end point within 5 years. Model validation showed good discrimination between high and low 5-year risk patients (Harrell C index of 0.73 [95% CI, 0.65-0.81]) but tended to overestimate this risk (calibration slope of 0.20 [95% CI, 0.03-0.36]). In our population, the strongest independent predictors of major clinical events were a history of heart failure and at least mild impairment of the subpulmonary left ventricle function.

CONCLUSIONS

We reported the first external validation of a major clinical events risk model in a large cohort of adults with transposition of the great arteries. The model allows for distinguishing patients at low risk from those at intermediate to high risk. Previous episode of heart failure and subpulmonary left ventricle dysfunction appear to be key markers in the prognosis of patients. Further optimizing risk models are needed to individualize risk predictions in patients with transposition of the great arteries.

Arrhythmias in Adult Congenital Heart Disease Heart Failure

Heart failure and arrhythmias represent 2 major causes of mortality and morbidity in adults with congenital heart disease. Arrhythmias and heart failure are interdependent, and one may exacerbate the other. Treatment of one also has a positive impact on the other. Management approaches need to be multifaceted, including pharmacotherapy, optimization of hemodynamic status with catheter-based or surgical interventions, and specific management of arrhythmia with device or catheter ablation therapy.

Trends in prevalence of major etiologies leading to heart failure in young patients: An integrative review

The prevalence of Heart failure (HF) is increasing with the aging of the population but it is estimated that 10% of HF patients are younger than 50 years-old. HF development in this population is characterized with a fast-growing prevalence, and important disparities according to underlying etiologies or gender. These observations highlight the need to identify specific and preventable factors in these patients, a topic that is under-studied. Here we provide an overview of trends in prevalence of major etiologies leading to HF in young subjects, including genetic factors associated with cardiomyopathies, premature vascular dysfunction and related ischemia, metabolic stress, cardio-toxic responses to different agents, and myocarditis. We also highlight the increasing influence of major risk factors that are driving HF in younger patients, such as obesity, diabetes or arterial hypertension.

Valvular Regurgitation in Adults with Congenital Heart Disease and Heart Failure: Current Status and Potential Interventions

The great majority of patients born with congenital heart disease (CHD) are living well into adulthood, yet they often have residual hemodynamic lesions, including valvar regurgitation. As these complex patients grow older, they are at risk of developing heart failure, which can be exacerbated by the underlying valvular regurgitation. In this review, we describe the etiologies of heart failure related to valvular regurgitation in the CHD population and discuss potential interventions.

Overview of Long-Term Outcome in Adults with Systemic Right Ventricle and Transposition of the Great Arteries: A Review

The population of patients with a systemic right ventricle (sRV) in biventricular circulation includes those who have undergone an atrial switch operation for destro-transposition of the great arteries (d-TGA) and those with congenitally corrected transposition of the great arteries (ccTGA). Despite the life expectancy of these patients is significantly increased, the long-term prognosis remains suboptimal due to late complications such as heart failure, arrhythmias, and premature death. These patients, therefore, need a close follow-up to early identify predictive factors of adverse outcomes and to implement all preventive therapeutic strategies. This review analyzes the late complications of adult patients with an sRV and TGA and clarifies which are risk factors for adverse prognosis and which are the therapeutic strategies that improve the long-term outcomes. For prognostic purposes, it is necessary to monitor sRV size and function, the tricuspid valve regurgitation, the functional class, the occurrence of syncope, the QRS duration, N-terminal pro B-type natriuretic peptide levels, and the development of arrhythmias. Furthermore, pregnancy should be discouraged in women with risk factors. Tricuspid valve replacement/repair, biventricular pacing, and implantable cardioverter defibrillator are the most important therapeutic strategies that have been shown, when used correctly, to improve long-term outcomes.

Heart failure in systemic right ventricle: Mechanisms and therapeutic options

d-loop transposition of the great arteries (d-TGA) and congenitally corrected transposition of the great arteries (cc-TGA) feature a right ventricle attempting to sustain the systemic circulation. A systemic right ventricle (sRV) cannot support cardiac output in the long run, eventually decompensating and causing heart failure. The burden of d-TGA patients with previous atrial switch repair and cc-TGA patients with heart failure will only increase in the coming years due to the aging adult congenital heart disease population and improvements in the management of advanced heart failure. Clinical data still lags behind in developing evidence-based guidelines for risk stratification and management of sRV patients, and clinical trials for heart failure in these patients are underrepresented. Recent studies have provided foundational data for the commencement of robust clinical trials in d-TGA and cc-TGA patients. Further insights into the multifactorial nature of sRV failure can only be provided by the results of such studies. This review discusses the mechanisms of heart failure in sRV patients with biventricular circulation and how these mediators may be targeted clinically to alleviate sRV failure.

Clinical Modelling of RVHF Using Pre-Operative Variables: A Direct and Inverse Feature Extraction Technique

Right ventricular heart failure (RVHF) mostly occurs due to the failure of the left-side of the heart. RVHF is a serious disease that leads to swelling of the abdomen, ankles, liver, kidneys, and gastrointestinal (GI) tract. A total of 506 heart-failure subjects from the Faculty of Medicine, Cardiovascular Surgery Department, Ege University, Turkey, who suffered from a severe heart failure and are currently receiving support from a ventricular assistance device, were involved in the current study. Therefore, the current study explored the application of both the direct and inverse modelling approaches, based on the correlation analysis feature extraction performance of various pre-operative variables of the subjects, for the prediction of RVHF. The study equally employs both single and hybrid paradigms for the prediction of RVHF using different pre-operative variables. The visualized and quantitative performance of the direct and inverse modelling approach indicates the robust prediction performance of the hybrid paradigms over the single techniques in both the calibration and validation steps. Whereby, the quantitative performance of the hybrid techniques, based on the Nash-Sutcliffe coefficient (NC) metric, depicts its superiority over the single paradigms by up to 58.7%/75.5% and 80.3%/51% for the calibration/validation phases in the direct and inverse modelling approaches, respectively. Moreover, to the best knowledge of the authors, this is the first study to report the implementation of direct and inverse modelling on clinical data. The findings of the current study indicates the possibility of applying these novel hybridised paradigms for the prediction of RVHF using pre-operative variables.

Heart Failure in Complex Congenital Heart Disease of the Adult

PURPOSE OF REVIEW

Adult congenital heart disease (ACHD) patients have demonstrated improved survival, especially those with severely complex disease, mainly single-ventricle/Fontan physiology and those with a systemic right ventricle. We describe the heart failure phenotypes of complex CHD, reversible causes for heart failure, and considerations for advanced therapy.

RECENT FINDINGS

While initially marketed for application to patients with acquired causes for heart failure, newer devices and technologies have started to be used in the ACHD population. After reversible causes for heart failure in CHD are addressed, it is reasonable to consider use of new device-based technologies and orthotopic heart transplant (OHT) for end-stage disease. New heart failure technology and organ transplant should carefully be considered and applied in complex ACHD, where there may be significant improvement in morbidity and mortality.

A practical guideline for performing a comprehensive transthoracic echocardiogram in the congenital heart disease patient: consensus recommendations from the British Society of Echocardiography

Transthoracic echocardiography is an essential tool in the diagnosis, assessment, and management of paediatric and adult populations with suspected or confirmed congenital heart disease. Congenital echocardiography is highly operator-dependent, requiring advanced technical acquisition and interpretative skill levels. This document is designed to complement previous congenital echocardiography literature by providing detailed practical echocardiography imaging guidance on sequential segmental analysis, and is intended for implementation predominantly, but not exclusively, within adult congenital heart disease settings. It encompasses the recommended dataset to be performed and is structured in the preferred order for a complete anatomical and functional sequential segmental congenital echocardiogram. It is recommended that this level of study be performed at least once on all patients being assessed by a specialist congenital cardiology service. This document will be supplemented by a series of practical pathology specific congenital echocardiography guidelines. Collectively, these will provide structure and standardisation to image acquisition and reporting, to ensure that all important information is collected and interpreted appropriately.

Status of adult outpatients with congenital heart disease in Japan: The Japanese Network of Cardiovascular Departments for Adult Congenital Heart Disease Registry

BACKGROUND

The Japanese Network of Cardiovascular Departments for Adult Congenital Heart Disease (JNCVD-ACHD) was founded in 2011 for the lifelong care of adult patients with congenital heart disease (ACHD patients). This network maintains the first Japanese ACHD registry.

METHODS AND RESULTS

From 2011 to 2019, the JNCVD-ACHD registered 54 institutions providing specialized care for ACHD patients in 32 of the 47 prefectures in Japan. The registry collected data on the disease profile for 24,048 patients from 50 institutions and the patient characteristics for 9743 patients from 24 institutions. The most common ACHDs were atrial septal defect (20.5 %), ventricular septal defect (20.5 %), tetralogy of Fallot (12.9 %), and univentricular heart (UVH)/single ventricle (SV; 6.6 %). ACHD patients without biventricular repair accounted for 37.0 % of the population. Also examined were the serious anatomical and/or pathophysiological disorders such as pulmonary arterial hypertension (3.0 %) including Eisenmenger syndrome (1.2 %), systemic right ventricle under biventricular circulation (sRV-2VC; 2.8 %), and Fontan physiology (6.0 %). The sRV-2VC cases comprised congenitally corrected transposition of the great arteries without anatomical repair (61.9 %) and transposition of the great arteries with atrial switching surgery (38.1 %). The primary etiology (86.4 %) for Fontan physiology was UVH/SV. In addition, developmental/chromosomal/genetic disorders were heterotaxy syndromes (asplenia, 0.9 %; polysplenia, 0.7 %), trisomy 21 (4.0 %), 22q11.2 deletion (0.9 %), Turner syndrome (0.2 %), and Marfan syndrome (1.1 %).

CONCLUSIONS

Although the specific management of ACHD has systematically progressed in Japan, this approach is still evolving. For ideal ACHD care, the prospective goals for the JNCVD-ACHD are to create local networks and provide a resource for multicenter clinical trials to support evidence-based practice.

Comparing Long-Term Sequelae of the Systemic Right Ventricle: An Overview of Single Versus Biventricular Arrangements

Patients with systemic right ventricles (RV) are at risk for heart failure and sudden cardiac death. Contributing factors to RV dysfunction include increased afterload from the systemic circulation, coronary insufficiency, progressive tricuspid valve regurgitation, the presence of residual lesions after palliation and arrhythmias. While all patients with a systemic right ventricle (SRV) are vulnerable to heart failure, there are distinct differences between patients with congenital dextro-transpostion of the great arteries (d-TGA) repaired by atrial switch, unrepaired congenitally corrected transposition of the great arteries (cc-TGA) and single systemic right ventricles palliated with a Fontan operation. Herein, we explore both the similarities and differences in progression of heart failure by phenotype as well as both the advancements and limitations in treatment options by each type of SRV.

Impact of pregnancy on natural history of systemic right ventricle in women with transposition of the great arteries

In the recent years, the pregnancy trend among women with Congenital Heart Disease (CHD) has increased; this has leaded to a growing demand for specialized care both in mother and in children. Although pregnancy is often well tolerated, maternal CHD may affect in some cases a maladaptive hemodynamic response carrying additional risks of cardiovascular events like arrhythmias, heart failure and, in rare cases, death. The impaired utero-placental perfusion due to maternal cardiac status may result in placental dysfunction, which may be associated with fetal growth restriction, preeclampsia, premature birth and perinatal morbidity. Systemic Right Ventricle (SRV) is one of the main conditions under which pregnancy is challenging. The sub-aortic position of morphological Right Ventricle (RV) is "physiologically" predisposed to fail at the adult age and may be potentially inadequate to support the hemodynamic stress of the pregnancy. Current literature about pregnancy in women with SRV consists of small retrospective series not providing conclusive evidence about the feasibility of a successful pregnancy outcomes. In addition, the long-term effects of pregnancy on SVR are not still adequately investigated and it remains unclear if maternal complications reported are due to pregnancy or to natural history of SVR. The aim of this paper is to offer a critical review of the knowledges at regard and to provide a practice update on the risk assessment and the pregnancy management in women with SRV in order to support the decision making and to optimize outcomes in these patients.

Congenitally corrected transposition of great arteries: a case series of five unoperated African children

Background

Congenitally corrected transposition of great arteries (ccTGA) is rare. It is commonly associated with ventricular septal defect (VSD), pulmonary stenosis and heart block. Early anatomic repair is recommended between 3 and 6 months of age to prevent development of tricuspid valve regurgitation and systemic right ventricular failure.

Case presentation

We retrospectively identified five cases of ccTGA. Cases were between one and 13 years of age. All the cases were unoperated. Four of the five cases had associated intracardiac defects/complications. These included: VSD, pulmonary stenosis, tricuspid valve regurgitation, right ventricular systolic dysfunction and heart block.

Conclusion

These cases demonstrate the challenges of access to early diagnosis and surgery in a low resource setting. This delay in anatomic repair leads to complications of tricuspid valve regurgitation and systemic right ventricular failure.

Clinical characteristics and outcomes of patients with adult congenital heart disease listed for heart and heart‒lung transplantation in the Eurotransplant region

BACKGROUND

The therapeutic success in patients with congenital heart disease (CHD) leads to a growing number of adults with CHD (adult CHD [ACHD]) who develop end-stage heart failure. We aimed to determine patient characteristics and outcomes of ACHD listed for heart transplantation.

METHODS

Using data from all the patients with ACHD in 20 transplant centers in the Eurotransplant region from 1999 to 2015, we analyzed patient characteristics, waiting list, and post-transplantation outcomes.

RESULTS

A total of 204 patients with ACHD were listed during the study period. The median age was 38 years, and 62.3% of the patients were listed in high urgency (HU), and 37.7% of the patients were in transplantable (T)-listing status. A total of 23.5% of the patients died or were delisted owing to clinical worsening, and 75% of the patients underwent transplantation. Median waiting time for patients with HU-listing status was 4.18 months and with T-listing status 9.07 months. There was no difference in crude mortality or delisting between patients who were HU status listed and T status listed (p = 0.65). In multivariable regression analysis, markers for respiratory failure (mechanical ventilation, hazard ratio [HR]: 1.41, 95% CI: 1.11-1.81, p = 0.006) and arrhythmias (anti-arrhythmic medication, HR: 1.42, 95% CI: 1.01-2.01, p = 0.044) were associated with a higher risk of death or delisting. In the overall cohort, post-transplantation mortality was 26.8% after 1 year and 33.4% after 5 years.

CONCLUSIONS

Listed patients are at high risk of death without differences in the urgency of listing. Respiratory failure requiring invasive ventilation and possibly arrhythmias requiring anti-arrhythmic medication indicate worse outcomes on waiting list.

Association between reduced heart rate variability components and supraventricular tachyarrhythmias in patients with a systemic right ventricle

BACKGROUND

Patients with a systemic right ventricle are prone to develop heart failure. Abnormal heart rate variability (HRV), a measure of autonomic dysfunction, is associated with morbidity and mortality in patients with left ventricular failure. The association between HRV and supraventricular arrhythmias (SVTs), which are associated with adverse events in this population, was assessed.

METHODS

24-Hour Holter recordings of patients with a systemic right ventricle and healthy controls were analysed in a retrospective cohort study. HRV was calculated and compared between groups. Correlation coefficients were determined for HRV variables and clinical characteristics. The relation between HRV and SVTs was investigated with linear regression.

RESULTS

The patient group included 29 patients (69%) late after Mustard or Senning correction for transposition of the great arteries, and 13 patients with congenitally corrected transposition of the great arteries (31%). The control group included 38 subjects. HRV was significantly lower in patients compared with controls. In the patient group, lower SDANN (standard deviation of the average NN intervals calculated over 5-minute intervals) was independently associated with a higher number of supraventricular arrhythmias (95% CI -0.03 to -0.0004, p = 0.045). In exploratory correlation analysis, several HRV variables correlated with echocardiographic systemic right ventricular function (rho = 0.36, p = 0.02 for SDANN), and exercise capacity (rho = 0.39, p = 0.05 for SDANN).

CONCLUSION

In patients with a systemic right ventricle, HRV is lower compared with controls and (SDANN) is independently associated with supraventricular arrhythmias.