Update on tetralogy of Fallot for the adult cardiologist including a brief historical and surgical perspective

The challenges of an aging tetralogy of Fallot population

Introduction: Advancements in surgery and management have resulted in a growing population of aging adults with tetralogy of Fallot (TOF). As a result, there has been a parallel growth in late complications associated with the sequelae from the underlying cardiac anomalies as well as the surgical and other interventional treatments.Areas covered: Here, we review challenges related to an aging population of patients with TOF, particularly late complications, and highlight advances in management and key areas for future research. Pulmonary regurgitation, heart failure, arrhythmias, and aortic complications are some of these late complications. There is also a growing incidence of acquired cardiovascular disease, obesity, and diabetes associated with aging. Management of these late complications and acquired comorbidities continues to evolve as research provides insights into long-term outcomes from medical therapies and surgical interventions.Expert opinion: The management of an aging TOF population will continue to transform with advances in imaging technologies to identify subclinical disease and valve replacement technologies that will prevent and mitigate disease progression. In the coming years, we speculate that there will be more data to support the use of novel heart failure therapies in TOF and consensus guidelines on the management of refractory arrhythmias and aortic complications.

The Optimal Tetralogy of Fallot Repair Using Generative Adversarial Networks

Background

Tetralogy of Fallot (TOF) is a type of congenital cardiac disease with pulmonary artery (PA) stenosis being the most common defect. Repair surgery needs an appropriate patch to enlarge the narrowed artery from the right ventricular (RV) to the PA.

Methods

In this work, we proposed a generative adversarial networks (GANs) based method to optimize the patch size, shape, and location. Firstly, we built the 3D PA of patients by segmentation from cardiac computed tomography angiography. After that, normal and stenotic areas of each PA were detected and labeled into two sub-images groups. Then a GAN was trained based on these sub-images. Finally, an optimal prediction model was utilized to repair the PA with patch augmentation in the new patient.

Results

The fivefold cross-validation (CV) was performed for optimal patch prediction based on GANs in the repair of TOF and the CV accuracy was 93.33%, followed by the clinical outcome. This showed that the GAN model has a significant advantage in finding the best balance point of patch optimization.

Conclusion

This approach has the potential to reduce the intraoperative misjudgment rate, thereby providing a detailed surgical plan in patients with TOF.

Comparison of right ventricular outflow tract gradient under anesthesia with post-operative gradient in patients undergoing tetralogy of Fallot repair

Background:

Intra-cardiac repair for tetralogy of Fallot has some degree of residual right ventricular outflow tract (RVOT) obstruction. However, the measurement of this gradient intra-operatively might get affected by the depth of anesthesia which is important for the long-term outcome.

Aims:

The primary aim was to compare intraoperative RVOT gradient post repair under two different anesthetic depths of 1% and 2% end-tidal sevoflurane. The secondary objective was to follow up the changes in RVOT gradient till 1 month postoperatively. Design: Observational study. Setting : Advanced Cardiac Centre of PGIMER, Chandigarh.

Methods:

Following intracardiac repair, RVOT gradient was measured directly by placing needle into the right ventricle and pulmonary artery at sevoflurane 1%, and subsequently, at 2% end.tidal concentration while maintaining hemodynamic stability. These gradients were also measured using transesophageal echocardiography (TEE) (ClinicalTrials.gov NCT03234582).

Results:

Twenty-one patients were included in this study that had intra-cardiac repair, of which pulmonary annulus was preserved for 15 cases. Mean RVOT gradients measured invasively and by TEE at end-tidal sevoflurane concentration of 1% and 2% were not significantly different (6.67 ± 4.16 mmHg vs. 6.76 ± 3.82 mmHg, P > 0.05 invasively and 13.01 ± 7.40 mmHg vs. 12.53 ± 7.11 mmHg, P > 0.05 by TEE, respectively). RVOT gradient measured by trans-thoracic echocardiography (TTE) postoperatively at the time of extubation and during follow-up at 1 month showed significant reduction (11.37 ± 6.00 mmHg, P < 0.05 and 9.23 ± 4.92 mmHg, P < 0.01 respectively). Six patients who underwent repair with transannular patch had significant pulmonary regurgitation (PR) following surgery, with no significant change in PR severity or RVOT gradient on increasing anesthetic depth.

Conclusions:

Postoperative RVOT gradient was not altered by changing depth of anesthesia provided systemic blood pressure was maintained. One month postrepair RVOT gradients were significantly reduced as compared to the intraoperative values.

Preprocedural Imaging Evaluation of Pulmonary Valve Replacement After Repair of Tetralogy of Fallot: What the Radiologist Needs to Know

Tetrallogy of Fallot (TOF) is the most frequent form of cyanotic congenital heart disease. Despite advances in surgical and medical treatment, mortality remains high. Residual dysfunction of the pulmonary valve (PV) after correction of right ventricular outflow tract obstruction is an important cause of morbidity, leading to irreversible right ventricular dysfunction, arrhythmias, heart failure and occasionally, death. The strategies for PVR have evolved over the last decades, and the timing of the intervention remains the foundation of the decision-making process. Symptoms of heart failure are unreliable indicators for optimal timing of repair. Imaging plays an essential role in the assessment of PV integrity and dysfunction. The identification of the best timing for PVR requires a multimodality approach. Transthoracic echocardiography is the most commonly used imaging modality for the initial assessment and follow-up of TOF patients, although its utility has technical limitations, especially in adults. Cardiac computed tomography and magnetic resonance imaging are now routinely used for preoperative and postoperative evaluation of these patients, and provide highly valuable information about the anatomy and pathophysiology. Imaging evidence of disease progression is now part of the major guidelines to define the best timing for reintervention. The purpose of this article is to review the pathophysiology after TOF repair, identify the main imaging anatomic and physiologic features, describe the indications for PVR and recognize the role of imaging in the assessment of these patients to define the appropriate timing of PVR.

Management of an Adult Patient With Congenital Heart Disease

The health care environment in the United States heralds changing population demographics, presenting challenges for modern health care systems. The most remarkable impetus for prodigious medical luminary attention is the expanding growth of aging adults in the population. Individuals born with congenital heart disease (CHD) are a subset of this demographic evolution reflecting current health care trends. Where historically limited prognoses underscored the expansion and quality of life for individuals born with CHD, current technological advancements now pave the road to lengthy existence for these individuals, creating an aging population of patients with CHD needing access to health care. The advanced practice registered nurse (APRN) is called on to fill gaps in health care access issues and should be prepared to serve this population.

Microvolt T-wave alternans in adult patients with repaired tetralogy of Fallot

OBJECTIVE

Indications for sudden cardiac death (SCD) primary prevention are unknown in patients with repaired tetralogy of Fallot (ToF). The role of microvolt T-wave alternans (MTWA) in SCD risk stratification was documented. However, the prevalence of spectral MTWA and its association with ventricular arrhythmia (VA) in adults after ToF repair were not elucidated.

DESIGN

Microvolt T-wave alternans, electrocardiogram (ECG), ambulatory ECG monitoring, echocardiography, and spiroergometry were evaluated in 102 adults after ToF repair. Microvolt T-wave alternans results were classified as normal: negative(-), abnormal: positive(+), and indeterminate(ind). Owing to similar prognostic significance, MTWA(+) and MTWA(ind) due to patient factors were combined into nonnegative group: MTWA(abnormal).

RESULTS

Microvolt T-wave alternans(abnormal) was more frequent in the studied group as compared with controls (P = .0005). The MTWA(abnormal) group had greater right ventricular end-diastolic diameter (P = .005), higher incidence of pulmonary regurgitation (P = .015), lower peak oxygen consumption (P = .01), and higher VE/VCO2 slope (P = .04) in comparison with MTWA(normal). Univariate logistic regression proved pulmonary regurgitation (OR = 3.57, 95% CI 1.27-10.04), VA (OR = 3.26, 95% CI 1.06-10.05), right ventricular end-diastolic enlargement (OR = 1.11, 95% CI 1.03-1.2), increase in VE/VCO2 slope (OR = 1.08, 95% CI 1.01-1.17), and decrease in peak oxygen uptake (OR = .91, 95% CI 0.83-0.99) to increase MTWA(abnormal) prevalence.

CONCLUSIONS

In adults after ToF repair, abnormal MTWA occurred more often than in controls. Probability of abnormal MTWA did not rise with prevalence of malignant VA; however, presence of abnormal MTWA was associated with VA risk factors: pulmonary regurgitation, right ventricular enlargement, and consequent heart failure. The role of MTWA in selecting patients late after ToF repair at risk of SCD needs further observation.