Heart failure in systemic right ventricle: Mechanisms and therapeutic options

Diagnosis, management, and outcome of heart failure in congenitally corrected transposition of the great arteries (ccTGA)-a narrative review

Background and Objective

Congenitally corrected transposition of the great arteries (ccTGA) remains a rare congenital disorder with a wide range of manifestations. The management of heart failure (HF) of the systemic right ventricle (RV), arrhythmias, heart block, and acquired cardiac conditions require a complex and multi-faceted approach. The objective of this manuscript is to present the current evidence regarding diagnostic, treatment, and management strategies for HF in ccTGA, including ventricular assist device (VAD) therapy and heart transplantation.

Methods

A systematic review of the literature was conducted using PubMed, covering the period between 2010 and 2024. The search terms included "heart failure", "ccTGA", "VAD", "heart transplantation", and "systemic RV failure". Two clinical cases were included for illustrative purposes.

Key Content and Findings

HF is a common occurrence in the context of ccTGA, primarily driven by progressive pressure and volume overload of the systemic RV, regurgitation of the systemic atrio-ventricular (AV) valve, and the development of arrhythmias, including complete heart block and (supra-)ventricular tachycardia. The use of HF medication is indicated for symptomatic patients, however, data on the efficacy of standardized HF medication remains limited. Timing of AV-valve replacement is essential to prevent further progression of HF.

Conclusions

In ccTGA, the timing of surgery and interventional treatment approaches, the effect of pharmacological treatment in the context of HF, as well as the timing of initiation of a mechanical circulatory support, VAD and heart transplantation, are based on individualised consensus-level decisions. Optimal management remains a topic of debate due to the scarcity of outcome data. Future investigations should focus on identifying surrogate parameters for guiding treatment.

Heart failure in patients with a systemic right ventricle: A multicentre study with long-term follow-up

AIMS

Adult patients with transposition of the great arteries (TGA) and an systemic right ventricle (sRV) are at risk for heart failure (HF). In this study, we investigated risk factors for HF hospitalization and developed a novel risk stratification tool to optimize risk prediction for clinical practice.

METHODS AND RESULTS

In this international multicentre study, 522 patients with TGA and an sRV, without history of HF hospitalization, were followed retrospectively for a median of 17.9 years (interquartile range [IQR] 12.9-22.1). HF hospitalization was defined as a hospital admission for HF signs and symptoms with initiation or increase of HF medication. Predictors for HF hospitalization were established using a Cox regression analysis and were used to build a 10-year risk score. Of the 522 patients, 70% had an atrial switch operation and 30% had a congenitally corrected TGA. The median age at time of enrolment was 23.7 years (IQR 19.9-32.1) and 64% were male. During follow-up, 127 patients (24.3%) had at least one HF hospitalization. A risk stratification tool was built using the following independent predictors associated with a 10-year risk of HF hospitalization: age, New York Heart Association functional class ≥II, QRS duration >120 ms, atrial fibrillation, moderate/severe right ventricular dysfunction, with a C-statistic of 0.868 (95% confidence interval 0.823-0.913).

CONCLUSION

During follow-up, 24.3% of sRV patients had at least one HF hospitalization. Five simple, clinically-accessible variables can be used as a risk score tool to identify patients at higher risk of HF hospitalization.

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.

Novel Therapies for Right Ventricular Failure

PURPOSE OF REVIEW

Traditionally viewed as a passive player in circulation, the right ventricle (RV) has become a pivotal force in hemodynamics. RV failure (RVF) is a recognized complication of primary cardiac and pulmonary vascular disorders and is associated with a poor prognosis. Unlike treatments for left ventricular failure (LVF), strategies such as adrenoceptor signaling inhibition and renin-angiotensin system modulation have shown limited success in RVF. This review aims to reassure about the progress in RVF treatment by exploring the potential of contemporary therapies for heart failure, including angiotensin receptor and neprilysin inhibitors, sodium-glucose co-transporter 2 inhibitors, and soluble guanylate cyclase stimulators, which may be beneficial for treating RV failure, particularly when associated with left heart failure. Additionally, it examines novel therapies currently in the pipeline.

RECENT FINDINGS

Over the past decade, a new wave of RVF therapies has emerged, both pharmacological and device-centered. Novel pharmacological interventions targeting metabolism, calcium homeostasis, oxidative stress, extracellular matrix remodeling, endothelial function, and inflammation have shown significant promise in preclinical studies. There is also a burgeoning interest in the potential of epigenetic modifications as therapeutic targets for RVF. Undoubtedly, a deeper understanding of the mechanisms underlying RV failure, both with and without pulmonary hypertension, is urgently needed. This knowledge is not just a theoretical pursuit, but a crucial step that could lead to the development of pharmacological and cell-based therapeutic options that directly target the RV and pulmonary vasculature, aligning with the principles of precision medicine.

Pregnancy Outcomes in Women with Biventricular Circulation and a Systemic Right Ventricle: A Systematic Review

Background: Pregnancy in women with biventricular circulation and a systemic right ventricle (sRV) is considered high risk, with limited data available on pregnancy outcomes. This study aimed to investigate pregnancy outcomes in this population. Materials and Methods: A systematic review was conducted using four major electronic databases. Pregnant women with a complete transposition of great arteries (d-TGA) after an atrial switch operation or a congenitally corrected transposition of the great arteries (ccTGA) were included. Results: In total, 15 studies including 632 pregnancies in 415 women with an sRV and biventricular circulation were identified, of whom 299 (72%) had d-TGA and 116 (28%) ccTGA. Maternal mortality or cardiac transplantation occurred in 0.8% of pregnancies. The most frequent maternal complications were the worsening of systemic atrioventricular valve regurgitation [pooled estimate (PE): 16%, 95% CI: 5;26], the deterioration of sRV function (PE: 15%, 95% CI: 2;27), the worsening of the NYHA class (PE: 13%, 95% CI: 6;20), all-cause hospitalization (PE): 10%, 95% CI: 7;12), arrhythmias (PE: 8%, 95% CI: 5;11), and symptomatic heart failure (PE: 6%, 95% CI: 3;10). Stillbirth occurred in 0.7% of pregnancies and neonatal death in 0.4%. Small-for-gestational-age neonates were encountered in 36% (95% CI: 21;52) of pregnancies and preterm delivery in 22% (95% CI: 14;30). A subgroup analysis showed no significant difference in outcomes between women with d-TGA and those with ccTGA, except for the worsening of the NYHA class, which occurred more often in d-TGA (18%, 95% CI: 12;27 vs. 6%, 95% CI: 3;15, respectively, p = 0.03). Conclusions: Maternal and fetal/neonatal mortality are low among pregnant women with biventricular circulation and an sRV. However, significant maternal morbidity and poor neonatal outcomes are frequently encountered, rendering management in specialized centers imperative.

Brazilian Guideline for Exercise Testing in Children and Adolescents - 2024

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Pathogenesis and Surgical Treatment of Congenitally Corrected Transposition of the Great Arteries (ccTGA): Part III

Congenitally corrected transposition of the great arteries (ccTGA) is an infrequent and complex congenital malformation, which accounts for approximately 0.5% of all congenital heart defects. This defect is characterized by both atrioventricular and ventriculoarterial discordance, with the right atrium connected to the morphological left ventricle (LV), ejecting blood into the pulmonary artery, while the left atrium is connected to the morphological right ventricle (RV), ejecting blood into the aorta. Due to this double discordance, the blood flow is physiologically normal. Most patients have coexisting cardiac abnormalities that require further treatment. Untreated natural course is often associated with progressive failure of the systemic right ventricle (RV), tricuspid valve (TV) regurgitation, arrhythmia, and sudden cardiac death, which occurs in approximately 50% of patients below the age of 40. Some patients do not require surgical intervention, but most undergo physiological repair leaving the right ventricle in the systemic position, anatomical surgery which restores the left ventricle as the systemic ventricle, or univentricular palliation. Various types of anatomic repair have been proposed for the correction of double discordance. They combine an atrial switch (Senning or Mustard procedure) with either an arterial switch operation (ASO) as a double-switch operation or, in the cases of relevant left ventricular outflow tract obstruction (LVOTO) and ventricular septal defect (VSD), intra-ventricular rerouting by a Rastelli procedure. More recently implemented procedures, variations of aortic root translocations such as the Nikaidoh or the half-turned truncal switch/en bloc rotation, improve left ventricular outflow tract (LVOT) geometry and supposedly prevent the recurrence of LVOTO. Anatomic repair for congenitally corrected ccTGA has been shown to enable patients to survive into adulthood.

Importance of Cardiovascular Magnetic Resonance Applied to Congenital Heart Diseases in Pediatric Age: A Narrative Review

Congenital heart diseases (CHDs) represent a heterogeneous group of congenital defects, with high prevalence worldwide. Non-invasive imaging is essential to guide medical and surgical planning, to follow the patient over time in the evolution of the disease, and to reveal potential complications of the chosen treatment. The application of cardiac magnetic resonance imaging (CMRI) in this population allows for obtaining detailed information on the defects without the necessity of ionizing radiations. This review emphasizes the central role of CMR in the overall assessment of CHDs, considering also the limitations and challenges of this imaging technique. CMR, with the application of two-dimensional (2D) and tri-dimensional (3D) steady-state free precession (SSFP), permits the obtaining of very detailed and accurate images about the cardiac anatomy, global function, and volumes' chambers, giving essential information in the intervention planning and optimal awareness of the postoperative anatomy. Nevertheless, CMR supplies tissue characterization, identifying the presence of fat, fibrosis, or oedema in the myocardial tissue. Using a contrast agent for angiography sequences or 2D/four-dimensional (4D) flows offers information about the vascular, valvular blood flow, and, in general, the cardiovascular system hemodynamics. Furthermore, 3D SSFP CMR acquisitions allow the identification of coronary artery abnormalities as an alternative to invasive angiography and cardiovascular computed tomography (CCT). However, CMR requires expertise in CHDs, and it can be contraindicated in patients with non-conditional devices. Furthermore, its relatively longer acquisition time and the necessity of breath-holding may limit its use, particularly in children under eight years old, sometimes requiring anesthesia. The purpose of this review is to elucidate the application of CMR during the pediatric age.

Approach to Decompensated Right Heart Failure in the Acute Setting

Acute right heart failure (ARHF) arises when the right ventricle fails to pump blood efficiently to the pulmonary circulation. This inefficiency leads to a decreased blood supply to various organs. ARHF is a significant health concern, often leading to increased hospital admissions and being associated with a higher risk of mortality. This condition underscores the importance of effective cardiac care and timely intervention to manage its complications and improve patient outcomes. Diagnosing ARHF involves a comprehensive approach that includes a physical examination to evaluate the patient's fluid status and heart-lung function, blood tests to identify potential triggers and help forecast patient outcomes and various imaging techniques. These imaging techniques include electrocardiograms, point-of-care ultrasounds, computed tomography, cardiac magnetic resonance imaging, and other advanced monitoring methods. These diagnostic tools collectively aid in a detailed assessment of the patient's cardiac and pulmonary health, essential for effective management of ARHF. The management of ARHF focuses on addressing the underlying causes, regulating fluid balance, and enhancing cardiac function through pharmacological treatments or mechanical support aimed at boosting right heart performance. This management strategy includes the use of medications that modulate preload, afterload, and inotropy; vasopressors; anti-arrhythmic drugs; ensuring proper oxygenation and ventilation; and the utilization of heart and lung assist devices as a bridge to potential transplantation. This review article is dedicated to exploring the pathophysiology of ARHF, examining its associated morbidity and mortality, evaluating the various diagnostic tools available, and discussing the diverse treatment modalities. The article seeks to provide a comprehensive understanding of ARHF, its impact on health, and the current strategies for its management.

Complex Congenital Heart Disease in the Adult

Congenital heart disease (CHD), a heterogeneous group of structural abnormalities of the cardiovascular system, is the most frequent cause of severe birth defects. Related to improved pediatric outcomes, there are now more adults living with CHD, including complex lesions, than children. Adults with CHD are at high risk for complications related to their underlying anatomy and past surgical palliative interventions. Adults with CHD require close monitoring and proactive management strategies to improve outcomes.

Long-term outcome of patients with transposition of the great arteries and a systemic right ventricle: A systematic review and meta-analysis

BACKGROUND

Patients with a transposition of the great arteries (TGA) and a systemic right ventricle are at risk of heart failure (HF) development, arrhythmia and early mortality. Prognostic evaluations in clinical studies are hampered by small sample sizes and single-centred approaches. We aimed to investigate yearly rate of outcome and factors affecting it.

METHODS

A systematic literature search of four electronic databases (PubMed, EMBASE, Web of Science and Scopus) was conducted from inception to June 2022. Studies reporting the association of a systemic right ventricle with mortality with a minimal follow-up of 2 years during adulthood were selected. Incidence of HF hospitalization and/or arrhythmia were captured as additional endpoints. For each outcome, a summary effect estimate was calculated.

RESULTS

From a total of 3891 identified records, 56 studies met the selection criteria. These studies described the follow-up (on average 7.27 years) of 5358 systemic right ventricle patients. The mortality incidence was 1.3 (1-1.7) per 100 patients/year. The incidence of HF hospitalization was 2.6 (1.9-3.7) per 100 patients/year. Predictors of poor outcome were a lower left ventricular (LV) and right ventricular ejection fraction (RVEF) (standardized mean differences (SMD) of -0.43 (-0.77 to -0.09) and - 0.85 (-1.35 to -0.35), respectively), higher plasma concentrations of NT-proBNP (SMD of 1.24 (0.49-1.99)), and NYHA class ≥2 (risk ratio of 2.17 (1.40-3.35)).

CONCLUSIONS

TGA patients with a systemic right ventricle have increased incidence of mortality and HF hospitalization. A lower LVEF and RVEF, higher levels of NT-proBNP and NYHA class ≥2 are associated with poor outcome.