Improved Outcomes After Pulmonary Valve Replacement in Repaired Tetralogy of Fallot

Development and Validation of a Mortality Risk Score for Repaired Tetralogy of Fallot

BACKGROUND

Robust risk assessment is crucial for the growing repaired tetralogy of Fallot population at risk of major adverse clinical outcomes; however, current tools are hindered by lack of validation. This study aims to develop and validate a risk prediction model for death in the repaired tetralogy of Fallot population.

METHODS AND RESULTS

Patients with repaired tetralogy of Fallot enrolled in the INDICATOR (International Multicenter Tetralogy of Fallot Registry) cohort with clinical, arrhythmia, cardiac magnetic resonance, and outcome data were included. Patients from London, Amsterdam, and Boston sites were placed in the development cohort; patients from the Toronto site were used for external validation. Multivariable Cox regression was used to evaluate factors associated with time from cardiac magnetic resonance until the primary outcome: all-cause death. Of 1552 eligible patients (n=1221 in development, n=331 in validation; median age at cardiac magnetic resonance 23.4 [interquartile range, 15.6-35.6] years; median follow up 9.5 years), 102 (6.6%) experienced the primary outcome. The multivariable Cox model performed similarly during development (concordance index, 0.83 [95% CI, 0.78-0.88]) and external validation (concordance index, 0.80 [95% CI, 0.71-0.90]) and identified older age at cardiac magnetic resonance, obesity, type of tetralogy of Fallot repair, higher right ventricular end-systolic volume index, and lower biventricular global function index as independent predictors of death. A risk-scoring algorithm dividing patients into low-risk (score ≤4) versus high-risk (score >4) groups was validated to effectively discriminate risk of death (15-year survival of 95% versus 74%, respectively; P<0.001).

CONCLUSIONS

This externally validated mortality risk prediction algorithm can help identify vulnerable patients with repaired tetralogy of Fallot who may benefit from targeted interventions.

Contemporary multimodality non-invasive cardiac imaging protocols for tetralogy of Fallot

Tetralogy of Fallot is the most prevalent cyanotic congenital heart disease, requiring lifelong multimodality non-invasive cardiac imaging, such as echocardiography, cardiothoracic computed tomography, and cardiac magnetic resonance imaging. As imaging techniques continuously evolve and are gradually integrated into clinical practice, there is a critical need to update multimodality imaging protocols. Over the last two decades, cardiothoracic computed tomography imaging techniques have advanced remarkably, significantly enhancing its role in evaluating patients with tetralogy of Fallot. In this review, we describe contemporary multimodality non-invasive cardiac imaging protocols for tetralogy of Fallot, emphasizing the expanding role of cardiothoracic computed tomography. Additionally, we present standardized reporting forms designed to facilitate the clinical adoption of these protocols.

Repaired Tetralogy of Fallot: Have We Understood the Right Timing of PVR?

Despite many advances in surgical repair during the past few decades, the majority of tetralogy of Fallot patients continue to experience residual hemodynamic and electrophysiological abnormalities. The actual issue, which has yet to be solved, is understanding how this disease evolves in each individual patient and, as a result, who is truly at risk of sudden death, as well as the proper timing of pulmonary valve replacement (PVR). Our responsibility should be to select the most appropriate time for each patient, going above and beyond imaging criteria used up to now to make such a clinically crucial decision. Despite several studies on timing, indications, procedures, and outcomes of PVR, there is still much uncertainty about whether PVR reduces arrhythmia burden or improves survival in these patients and how to appropriately manage this population. This review summarizes the most recent research on the evolution of repaired tetralogy of Fallot (from adolescence onwards) and risk factor variables that may favor or delay PVR.

Impact of pulmonary valve replacement on ventricular function and cardiac events in patients with tetralogy of Fallot. A retrospective cohort study

INTRODUCTION AND OBJECTIVES

Our aim was to assess the impact of prosthetic pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot (rTOF) on changes in biventricular volumes and function and on adverse cardiac events.

METHODS

Adults with rTOF were identified from the SACHER-registry. Data from serial cardiac magnetic resonance imaging, echocardiography, exercise capacity and n-terminal pro b-type natriuretic peptide (NT-proBNP) were collected. The primary endpoint was right ventricular ejection fraction (RVEF) as measured by cardiac magnetic resonance. Secondary endpoints were biventricular volumes, left ventricular ejection fraction, exercise capacity and NT-proBNP levels, and time to adverse cardiac outcomes (atrial and ventricular arrhythmia, endocarditis). Associations between previous PVR and longitudinal changes in functional outcomes and time to adverse cardiac outcomes were analyzed using linear mixed-effects models and Cox proportional hazards models, respectively.

RESULTS

A total of 308 patients (153 with and 155 without PVR) with 887 study visits were analyzed. Previous PVR was not significantly associated with changes in RVEF (CE, -1.33; 95%CI, -5.87 to 3.21; P=.566). Previous PVR was associated with lower right ventricular end-diastolic volume but had no significant effect on left ventricular ejection fraction, exercise capacity, or NT-proBNP-levels. Previous PVR was associated with an increased hazard of atrial arrhythmias (HR, 2.09; 95%CI, 1.17-3.72; P=.012) and infective endocarditis (HR, 12.72; 95%CI, 4.69-34.49; P<.0001) but not with an increased hazard of sustained ventricular arrhythmias (HR, 0.64; 95%CI, 0.18-2.27; P=.490).

CONCLUSIONS

Previous PVR was not significantly associated with changes in RVEF but was associated with an increased risk of atrial arrhythmias and infective endocarditis.

Incremental value of machine learning for risk prediction in tetralogy of Fallot

OBJECTIVE

Machine learning (ML) can facilitate prediction of major adverse cardiovascular events (MACEs) in repaired tetralogy of Fallot (rTOF). We sought to determine the incremental value of ML above expert clinical judgement for risk prediction in rTOF.

METHODS

Adult congenital heart disease (ACHD) clinicians (≥10 years of experience) participated (one cardiac surgeon and four cardiologists (two paediatric and two adult cardiology trained) with expertise in heart failure (HF), electrophysiology, imaging and intervention). Clinicians identified 10 high-yield variables for 5-year MACE prediction (defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia and HF). Risk for MACE (low, moderate or high) was assigned by clinicians blinded to outcome for adults with rTOF identified from an institutional database (n=25 patient reviews conducted by five independent observers). A validated ML model identified 10 variables for risk prediction in the same population.

RESULTS

Prediction by ML was similar to the aggregate score of all experts (area under the curve (AUC) 0.85 (95% CI 0.58 to 0.96) vs 0.92 (0.72 to 0.98), p=0.315). Experts with ≥20 years of experience had superior discriminative capacity compared with <20 years (AUC 0.98 (95% CI 0.86 to 0.99) vs 0.80 (0.56 to 0.93), p=0.027). In those with <20 years of experience, ML provided incremental value such that the combined (clinical+ML) AUC approached ≥20 years (AUC 0.85 (95% CI 0.61 to 0.95), p=0.055).

CONCLUSIONS

Robust prediction of 5-year MACE in rTOF was achieved using either ML or a multidisciplinary team of ACHD experts. Risk prediction of some clinicians was enhanced by incorporation of ML suggesting that there may be incremental value for ML in select circumstances.

Editor-in-Chief's Top Picks From 2023

Each week, I record audio summaries for every paper in JACC, as well as an issue summary. This process has become a true labor of love due to the time they require, but I am motivated by the sheer number of listeners (16M+), and it has allowed me to familiarize myself with every paper that we publish. Thus, I have selected the top 100 papers (Original Investigations, Review Articles, Society Documents, and the Global Burden of Diseases) from distinct specialties each year. In addition to my personal choices, I have included papers that have been the most accessed or downloaded on our websites, as well as those selected by the JACC Editorial Board members. In order to present the full breadth of this important research in a consumable fashion, we will present these abstracts in this issue of JACC, as well as their Central Illustrations∗ and podcasts. The highlights comprise the following sections: Aorta; Basic and Translational Science; Cardiac Failure, Myocarditis, and Pericarditis; Cardiomyopathies and Genetics; Congenital Heart Disease; Coronary, Peripheral, and Structural Interventions; Coronavirus; Health Promotion and Preventive Cardiology; Imaging; Metabolic and Lipid Disorders; Neurovascular Disease and Dementia; Rhythm Disorders and Thromboembolism; and Valvular Heart Disease.1-104 ∗ To view the full manuscript, including the full-sized Central Illustration, please refer to the original publication in JACC.

From Other Journals: A Review of Recent Articles by Our Editorial Team

In this review, we provide a brief description of recently published articles addressing topics relevant to pediatric cardiologists. Our hope is to provide a summary of the latest articles published recently in other journals in our field. The articles address (1) A new index for prenatal diagnosis of total anomalous pulmonary venous return, (2) Outcomes of patients with Tetralogy of Fallot after pulmonary valve replacement (PVR), and (3) Short-term outcomes of the self expanding Harmony valve for transcatheter PVR.

Pulmonary Valve Replacement in Tetralogy of Fallot: Procedural Volume and Durability of Bioprosthetic Pulmonary Valves

BACKGROUND

Robust data on changes in pulmonary valve replacement (PVR) procedural volume and predictors of bioprosthetic pulmonary valve (BPV) durability in patients with tetralogy of Fallot (TOF) are scarce.

OBJECTIVES

This study sought to assess temporal trends in PVR procedural volume and BPV durability in a nationwide, retrospective TOF cohort.

METHODS

Data were obtained from patient records. Robust linear regression was used to assess temporal trends in PVR procedural volume. Piecewise exponential additive mixed models were used to estimate BPV durability, defined as the time from implantation to redo PVR with death as a competing risk, and to assess risk factors for reduced durability.

RESULTS

In total, 546 PVR were performed in 384 patients from 1976 to 2021. The annual number of PVR increased from 0.4 to 6.0 per million population (P < 0.001). In the last decade, the transcatheter PVR volume increased by 20% annually (P < 0.001), whereas the surgical PVR volume did not change significantly. The median BPV durability was 17 years (Q1: 10-Q3: 10 years-not applicable). There was no significant difference in the durability of different BPV after adjustment for confounders. Age at PVR (HR: 0.78 per 10 years from <1 year; 95% CI: 0.63-0.96; P = 0.02) and true inner valve diameter (9-17 mm vs 18-22 mm HR: 0.40; 95% CI: 0.22-0.73; P = 0.003 and 18-22 mm vs 23-30 mm HR: 0.59; 95% CI: 0.25-1.39; P = 0.23) were associated with reduced BPV durability in multivariate models.

CONCLUSIONS

The PVR procedural volume has increased over time, with a greater increment in transcatheter than surgical PVR during the last decade. Younger patient age at PVR and a smaller true inner valve diameter predicted reduced BPV durability.

Prognostic value of right ventricular dyssynchrony in adults with repaired tetralogy of Fallot

OBJECTIVE

Residual sequelae after surgical repair of tetralogy of Fallot (rTOF) affect clinical outcome. We investigated the prognostic impact of right ventricular (RV) dyssynchrony in adults with rTOF years after the surgical repair.

METHODS

Patients from the Swiss Adult Congenital HEart disease Registry were included. NT-proBNP levels, echocardiography, exercise testing and MRI data were collected. An offline strain analysis to quantify RV-ventricular and interventricular dyssynchrony was performed. The standard deviation of the time-to-peak shortening (TTP) of six RV segments defined the RV Dyssynchrony Index (RVDI). Maximal difference of TTP between RV and left ventricular segments defined the interventricular shortening delay (IVSD). Predictors of a composite adverse event (arrhythmias, hospitalisation for heart failure and death) were identified by multivariate Cox regression analysis. Their median values were used to create a risk score.

RESULTS

Out of 285 included patients (mean age 34±14 years), 33 patients (12%) experienced an adverse event during a mean follow-up of 48±21 months. No correlation was found between RVDI, IVSD and clinical events. NT-proBNP, right atrial area and peak heart rate were independent predictors of outcomes. After 4 years-follow-up, no adverse events occurred in patients at low risk (score=0 points), while an adverse event occurred in 62% of patients at high risk (score=3 points, p<0.001).

CONCLUSION

In our cohort of adults with rTOF, surrogates of RV dyssynchrony did not correlate with outcomes. A multimodality approach was effective in predicting the risk for adverse events.

Evaluation and Management of Sudden Death Risk in Repaired Tetralogy of Fallot

Although substantial progress has been made to prevent sudden cardiac death in repaired tetralogy of Fallot patients, ventricular arrhythmia and sudden death continue to be major causes of morbidity and mortality in these patients. Greater survival in contemporary cohorts has been attributed to enhanced surgical techniques, more effective management of heart failure, and increased efforts in risk stratification and management of ventricular arrhythmias. More recently, our understanding of predictive risk factors has evolved into personalized risk prediction tools that rely on comprehensive demographic, imaging, functional, and electrophysiological data. However, the universal applicability of these different scoring systems is limited due to differences between study cohorts, types of anatomic repair, imaging modalities, and disease complexity. Noninvasive risk stratification is critical to identify those who may derive benefit from catheter ablation or cardioverter defibrillator implantation for primary prevention. Ultimately, assessment and risk stratification by a multidisciplinary team is crucial to analyze the various complex factors for every individual patient and discuss further options with patients and their families.

Tetralogy of Fallot Across the Lifespan: A Focus on the Right Ventricle

Tetralogy of Fallot is a cyanotic congenital heart disease, for which various surgical techniques allow patients to survive to adulthood. Currently, the natural history of corrected tetralogy of Fallot is underlined by progressive right ventricular (RV) failure due to pulmonic regurgitation and other residual lesions. The underlying cellular mechanisms that lead to RV failure from chronic volume overload are characterized by microvascular and mitochondrial dysfunction through various regulatory molecules. On a clinical level, these cardiac alterations are commonly manifested as exercise intolerance. The degree of exercise intolerance can be objectified and aid in prognostication through cardiopulmonary exercise testing. The timing for reintervention on residual lesions contributing to RV volume overload remains controversial; however, interval assessment of cardiac function and volumes by echocardiography and magnetic resonance imaging may be helpful. In patients who develop clinically important RV failure, clinicians should aim to maintain a euvolemic state through the use of diuretics while paying particular attention to preload and kidney function. In patients who develop signs of cardiogenic shock from right heart failure, stabilization through the use of inotropes and pressor is indicated. In special circumstances, the use of mechanical support may be appropriate. However, cardiologists should pay particular attention to residual lesions that may impact the efficacy of the selected device.

Risk Stratification for Sudden Cardiac Death in Repaired Tetralogy of Fallot

There has been significant progress in the prevention of sudden cardiac death in repaired tetralogy of Fallot. Contemporary cohorts report greater survival attributable to improved surgical techniques, heart failure management, and proactive strategies for risk stratification and management of ventricular arrhythmias including defibrillator implantation and ablation technology. Over the last 25 years, our understanding of predictive risk factors has also improved from invasive and more limited measures to individualized risk prediction scores based on extensive demographic, imaging, electrophysiological, and functional data. Although each of these contemporary scoring systems improves prediction, there are important differences between the study cohorts, included risk factors, and imaging modalities that can significantly affect interpretation and implementation for the individual patient. In addition, accurate phenotyping of disease complexity and anatomic repair substantially modulates this risk and the mechanism of sudden death. Routine implementation of risk stratification within repaired tetralogy of Fallot management is important and directly informs primary prevention defibrillator implantation as well as consideration for proactive invasive strategies including ventricular tachycardia ablation and pulmonary valve replacement. Assessment and risk stratification by a multidisciplinary team of experts in adult congenital heart disease are crucial and critical. Although we have increased understanding, reconciliation of these complex factors for the individual patient remains challenging and often requires careful consideration and discussion with multidisciplinary teams, patients, and their families.

From Other Journals: A Review of Recent Articles by Our Editorial Team

In this review, we provide a brief description of recently published articles addressing topics relevant to pediatric cardiologists. This review includes (1) Fetal diagnosis, associated anomalies, and factors affecting outcomes in fetal congenitally corrected transposition of the great arteries (ccTGA), (2) The impact of Fontan-associated liver disease on heart and heart/liver transplant, (3) 1-year outcomes of the Harmony transcatheter pulmonary valve, (4) Risk factors associated with major adverse cardiac events in patients with pulmonary atresia and intact ventricular septum undergoing intervention, and (5) Benefits of pulmonary valve replacement in tetralogy of Fallot patients.

Pregnancy Considerations in Tetralogy of Fallot

The majority of women with repaired tetralogy of Fallot are able to tolerate pregnancy with a low risk of cardiovascular events. However, proactive contraceptive advice, prepregnancy counselling, and care by a pregnancy heart team with expertise in congenital heart disease are key to ensuring a good outcome for mother and baby. Maternal and fetal risks are increased in the presence of severe valvular stenosis, poorly tolerated arrhythmia, significant ventricular dysfunction, and cyanosis. It is unusual to see cyanotic adults with tetralogy of Fallot, whether unoperated or shunt palliated; pregnancy risks are greatly reduced by completing their repair before pregnancy is undertaken. The multidisciplinary pregnancy heart team should make a risk-stratified pregnancy care plan using a combination of published scoring systems and an individualized assessment of the patient's comorbidities. Low-risk patients may have the majority of their care and give birth in local units, whereas those at high risk should be managed and give birth in a tertiary centre with high-level expertise and intensive care facilities. Age-appropriate conversations about future childbearing and safe and reliable contraception should be part of routine follow-up from teenage years, so that women with tetralogy of Fallot can control their own fertility and make informed decisions about having children.

Use of Cardiovascular Magnetic Resonance for Risk Stratification in Repaired Tetralogy of Fallot

The risk of premature death in adult patients with repaired tetralogy of Fallot is real and not inconsiderable. From the third decade of life, the incidence of malignant ventricular arrhythmia (VA) is known to exponentially rise. Progressive adverse mechanoelectrical modelling because of years of volume and/or pressure overload from residual pulmonary valve dysfunction and ventricular scar creates the perfect catalyst for VA. Although potentially lifesaving, implantable cardiac defibrillators are associated with substantial psychological and physical morbidity. Better selection of patients most at risk of VA, so that implantable cardiac defibrillators are not inflicted on patients who will never need them, is therefore crucial and has inspired research on this topic for several decades. Cardiovascular magnetic resonance (CMR) enables noninvasive, radiation-free clinical assessment of anatomy and function, making it ideal for the lifelong surveillance of patients with congenital heart disease. Gold standard measurements of ventricular volumes and systolic function can be derived from CMR. Tissue characterization using CMR can identify a VA substrate and provides insight into myocardial disease. We detail risk factors for VA identified using currently available CMR techniques. We also discuss emerging and advanced CMR techniques that have not all yet translated into routine clinical practice. We review how CMR-defined predictors of VA in repaired tetralogy of Fallot can be incorporated into risk scores with other clinical factors to improve the accuracy of risk prediction and to allow for pragmatic clinical application. Finally, we discuss what the future may hold.

Advanced Imaging Technologies for Assessing Tetralogy of Fallot: Insights Into Flow Dynamics

Tetralogy of Fallot is the most common cyanotic congenital heart defect requiring surgical repair. Although surgical interventions have significantly reduced mortality, postrepair complications, such as pulmonary valve regurgitation and stenosis, may lead to adverse outcomes, including right ventricular dysfunction and increased risks of morbidity and mortality. This review explores the potential of advanced imaging technologies, including 4-dimensional-flow magnetic resonance imaging and high-frame-rate echocardiography, in providing valuable insights into blood flow dynamics and energy parameters. Quantitative measures, such as energy loss and vorticity, along with qualitative flow analysis, can provide additional insights into adverse haemodynamics at a potentially earlier and more reversible stage. Furthermore, personalized patient-specific information from these imaging modalities aids in guiding treatment decisions and monitoring postoperative interventions effectively. By characterizing flow patterns, these advanced imaging techniques hold great promise in improving the assessment and management of tetralogy of Fallot, providing tailored insights. However, further research and longitudinal studies are required to fully establish their clinical utility and potential impact on patient care.

Novel Therapeutic Strategies in Heart Failure in Adult Congenital Heart Disease: of Medicines and Devices

PURPOSE OF REVIEW

This paper reviews the latest literature on the growing field of heart failure in the adult congenital heart disease population.

RECENT FINDINGS

After highlighting the increasing prevalence and a few of the unique potential causes, including the concept of early senescence, this review begins with novel medical management strategies such as the angiotensin II receptor blocker and neprilysin inhibitors and sodium glucose cotransporter-2 inhibitors. Then, it addresses the latest applications of percutaneous techniques like implantable hemodynamic monitoring, transcatheter pulmonary and aortic valve replacement, and mitral clips. Cardiac resynchronization therapy and novel lymphatic system imaging and intervention are then described. Finally, the use of mechanical support devices, temporary and durable, is discussed as well as heart and combined heart and liver transplantation. There have been recent exciting advances in the strategies used to manage adult congenital heart disease patients with heart failure. As this population continues to grow, it is likely we will see further rapid evolution in this field.