Patterns of Aortic Dilation in Tetralogy of Fallot: An Analysis of 100 Fetal Echocardiograms Compared With Matched Controls

Background Although aortic dilation is common in tetralogy of Fallot (TOF), its progression and risk of dissection are not well understood. The mechanism of dilation is primarily attributed to increased flow in utero; an alternative is unequal septation of the truncus arteriosus resulting in a larger aorta and inherently hypoplastic pulmonary artery (PA). If the latter is true, we hypothesize the aorta to PA ratio in TOF is stable throughout gestation, and sums of great artery dimensions are similar to controls. Methods and Results We performed a single-center retrospective study of fetuses with TOF (2014-2020) and matched controls. We compared sums of diameters, circumferences, and cross-sectional areas of the aorta and PA and evaluated the aorta to PA ratio across gestation in 2 TOF subtypes: pulmonary stenosis and atresia (TOF-PA). There were 100 echocardiograms with TOF (36% TOF-PA) with median gestational age of 31 weeks (interquartile range 26.5-34.4) and median maternal age of 34 years (interquartile range 30-37). There were no differences in sums of great artery dimensions between TOF-pulmonary stenosis and controls. In TOF-PA, sums were significantly lower than controls (P values <0.01). The aorta to PA ratio was stable throughout gestation (Pearson's r=0.08 [95% CI, -0.12 to 0.27], -0.06 [95% CI, -0.25 to 0.14]). Conclusions The aorta in fetal TOF is large but grows proportionally throughout gestation, with sums of great artery dimensions similar to controls. TOF-PA appears distinct from TOF-pulmonary stenosis (with smaller sums), warranting further investigation. In conclusion, our findings suggest an intrinsic developmental mechanism contributes to aortic dilation in TOF.

ACR Appropriateness Criteria® Congenital or Acquired Heart Disease

Pediatric heart disease is a large and diverse field with an overall prevalence estimated at 6 to 13 per 1,000 live births. This document discusses appropriateness of advanced imaging for a broad range of variants. Diseases covered include tetralogy of Fallot, transposition of great arteries, congenital or acquired pediatric coronary artery abnormality, single ventricle, aortopathy, anomalous pulmonary venous return, aortopathy and aortic coarctation, with indications for advanced imaging spanning the entire natural history of the disease in children and adults, including initial diagnosis, treatment planning, treatment monitoring, and early detection of complications. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Unrepaired tetralogy of Fallot in a 71 years old woman: A case report and review of the literature

Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease (CHD) in infants. The four components that constitute ToF are an overriding aorta over the crest of the interventricular septum, obstruction in the right ventricular outflow tract, right ventricular hypertrophy, and a typically large non-restricted ventricular septal defect. ToF may also be associated with other extracardiac abnormalities, including patent ductus arteriosus or multiple aortopulmonary collateral arteries, which can impact the patient's survival. Patients with unoperated ToF rarely reach adulthood, and it is extremely rare to discover undiagnosed ToF in individuals over 60 years old. In this report, we describe an unusual case of a woman with unrepaired ToF who survived until the age of 71. She was fairly asymptomatic until the 7th decade of her life and complained only of dyspnea on exertion. The patient declined corrective cardiac surgery and preferred conservative management.

P-wave asystole after a tetralogy of Fallot correction surgery

A rarely seen arrhythmia is the p-wave asystole also mentioned ventricular asystole, ventricular standstill, or third-degree atrioventricular block with no ventricular escape rhythm. It is the result of the lack of impulse formation in ventricles (absence of idioventricular automaticity) or the failure of impulse transmission to ventricles (conduction disturbance)(1). As the name implies, the ventricles stop pumping, resulting in no effective cardiac output during the phenomenon. It is a potentially fatal rhythm disorder and need immediate diagnosis and treatment. We planned to present a case of p-wave asystole, which developed after tetralogy of Fallot total correction surgery.

Right ventricular outflow tract obstruction associated with neointimal tissue accumulation and distortion of the Harmony TPV25 stent frame: Potential mechanisms and treatment

BACKGROUND

The Harmony TPV25 transcatheter pulmonary valve (Medtronic Inc.) is constructed with a self-expanding stent frame comprising six zigged nitinol wires sewn together and covered with knitted polyester fabric, with flared inflow and outflow ends and a porcine pericardial valve sutured to the central portion of the device. It was approved for treatment of pulmonary regurgitation after prior right ventricular outflow tract repair in 2021. Early outcomes of this procedure have been excellent, but little is known about valve durability or ultimate mechanisms of dysfunction.

METHODS

We collected data on patients who underwent reintervention for TPV25 dysfunction and described findings related to distortion of the stent frame and tissue accumulation.

RESULTS

We describe six patients who underwent valve-in-valve implant for TPV25 obstruction (peak catheterization gradient peak 28-73 mmHg) 10-28 months after implant. In all cases, there was tissue accumulation within the inflow and valve-housing segments of the device and deformation of the self-expanding valve frame characterized by variable circumferential narrowing at the junction between the valve housing and the inflow and outflow portions of the device, with additional geometric changes in all segments. All six patients underwent valve-in-valve implant that results in a final peak gradient ≤10 mmHg and no regurgitation.

DISCUSSION

The occurrence of short-term Harmony TPV25 dysfunction in multiple patients with a similar appearance of frame distortion and tissue accumulation within the inflow and valve housing portions of the device suggests that this may be an important failure mechanism for this valve. Potential causes of the observed findings are discussed. It is possible to treat this mechanism of TPV25 dysfunction with valve-in-valve implant using balloon expandable transcatheter valves.

Anomalous right coronary artery from the pulmonary artery in an infant with tetralogy of Fallot

An anomalous right coronary artery from the pulmonary artery (ARCAPA) is a rare congenital anomaly that does not have the typical presentation of the more common anomalous left coronary artery. We present an infant with tetralogy of Fallot with atypical findings on the preoperative echocardiogram. A cardiac computerized tomographic (CT) scan showed ARCAPA. This was confirmed intraoperatively and repaired successfully. Close attention to coronaries on echocardiography and a low threshold for additional imaging can successfully diagnose ARCAPA in the presence of additional congenital heart defects.

Overcoming Underpowering in the Outcome Analysis of Repaired-Tetralogy of Fallot: A Multicenter Database from the CMR/CT Working Group of the Italian Pediatric Cardiology Society (SICPed)

Background: Managing repaired tetralogy of Fallot (TOF) patients is still challenging despite the fact that published studies identified prognostic clinical or imaging data with rather good negative predictive accuracy but weak positive predictive accuracy. Heterogeneity of the initial anatomy, the surgical approach, and the complexity of the mechanism leading to dilation and ventricular dysfunction explain the challenge of predicting the adverse event in this population. Therefore, risk stratification and management of this population remain poorly standardized. Design: The CMR/CT WG of the Italian Pediatric Cardiology Society set up a multicenter observational clinical database of repaired TOF evaluations. This registry will enroll patients retrospectively and prospectively assessed by CMR for clinical indication in many congenital heart diseases (CHD) Italian centers. Data collection in a dedicated platform will include surgical history, clinical data, imaging data, and adverse cardiac events at 6 years of follow-up. Summary: The multicenter repaired TOF clinical database will collect data on patients evaluated by CMR in many CHD centers in Italy. The registry has been set up to allow future research studies in this population to improve clinical/surgical management and risk stratification of this population.

Survival and Freedom From Reinterventions in Patients With Repaired Tetralogy of Fallot: Up to 42-Year Follow-Up of 917 Patients

Background To evaluate long-term outcome of tetralogy of Fallot repair analyzing an unbiased country-wide surgically treated population with tetralogy of Fallot. Methods and Results Retrospective analysis of consecutive patients aged <18 years who underwent tetralogy of Fallot repair at a single nationwide pediatric cardiac center. Death from any cause and need for surgical or catheter reintervention were the study end points. Cox regression analysis was used to identify related risk factors. A total of 917 patients (male, 56.3%) were analyzed. Staged repair was performed in 16.9%. Early mortality (24/917, 2.62% patients) was confined to the early surgical eras. Late mortality was 4.5% (40/893 patients). Survival probability was 95.1%, 93.8% and 91.9% at 10, 20 and 30 years after repair, respectively. Early surgical era (P=0.013) and surgical/catheter reinterventions (P<0.001) were multivariable predictors of late death. A total of 487 reinterventions were performed after initial repair in 253/917 patients (27.6%), with pulmonary artery revalvulation (196/917 patients, 21.4%) being most frequent. Probability of freedom from first reintervention was 89.0%, 73.3%, and 55.1% at 10, 20, and 30 years after primary repair, respectively. Transannular repair was associated with the need for pulmonary artery revalvulation (P<0.001). Patients who underwent staged repair were more likely to need reinterventions on pulmonary arteries (P<0.001). Conclusions In an unbiased nationwide cohort, tetralogy of Fallot repair carried a favorable survival of >90% at 30 years. Each reintervention significantly incrementally increased the risk of mortality. Type of initial repair predicted the need for specific surgical or catheter reinterventions.

Rationale and Design of the Multicenter Catheter Ablation of Ventricular Tachycardia Before Transcatheter Pulmonary Valve Replacement in Repaired Tetralogy of Fallot Study

Patients with repaired tetralogy of Fallot are at elevated risk for ventricular arrhythmia and sudden cardiac death. Over the past decade, the pathogenesis and natural history of ventricular tachycardia has become increasingly understood, and catheter ablation has emerged as an effective treatment modality. Concurrently, there has been great progress in the development of a versatile array of transcatheter valves that can be placed in the native right ventricular outflow tract for the treatment of long-standing pulmonary regurgitation. Although such valve platforms may eliminate the need for repeat cardiac operations, they may also impede catheter access to the myocardial substrates responsible for sustained macro-reentrant ventricular tachycardia. This manuscript provides the rationale and design of a recently devised multicenter study that will examine the clinical outcomes of a uniform, preemptive strategy to eliminate ventricular tachycardia substrates before transcatheter pulmonary valve implantation in patients with tetralogy of Fallot.

Right Aortic Arch with Bicarotid Trunk and Isolated Left Subclavian Artery: Hitherto Unreported Pattern

Variant arch anatomy may be seen associated with many congenital heart diseases. Its accurate preoperative identification is of paramount importance in optimal surgical planning of such cases. This case describes one such variant arch anatomy with two vessel right aortic arch, comprising of bicarotid trunk (giving rise to bilateral common carotid arteries) and right subclavian artery with isolation of the left subclavian artery, in a patient with tetralogy of Fallot. Right aortic arch with isolated left subclavian artery has already been described in association with tetralogy of Fallot. However, to the best of our knowledge, present arch pattern consisting of right aortic arch with bicarotid trunk and isolated left subclavian artery has not been reported in literature so far. Moreover, this case highlights the utility of multidetector computed tomography in accurate identification of variant arch anatomy in addition to delineation of cardiac and extracardiac details.

Association Between Preoperative Sarcopenia and Early Postoperative Outcomes in Pediatric Patients Undergoing Total Correction of Tetralogy of Fallot: A Retrospective Cohort Study

OBJECTIVES

To identify the association between preoperative low muscle mass and early postoperative outcomes in pediatric patients undergoing total correction of tetralogy of Fallot (TOF).

DESIGN

A retrospective cohort study.

SETTING

A single university hospital in Seoul, South Korea.

PARTICIPANTS

Pediatric patients (≤3 years) who underwent total correction of TOF between May 2008 and February 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cross-sectional areas of the pectoralis and erector spinae muscles were measured using preoperative chest computed tomography (CT) scans, and adjusted to body surface area to define muscle mass index. The patients were divided into sarcopenia, presarcopenia, and no sarcopenia groups based on cutoff values determined using the mean and SD of the muscle mass index in the third z-weight quintile. Of a total of 330 patients included in the final analysis, 13 were associated with the sarcopenia group, 57 in the presarcopenia group, and 260 in the no sarcopenia group. The sarcopenia group exhibited a higher incidence of major adverse events than the presarcopenia and no sarcopenia groups, respectively (38% v 25% v 18%; p = 0.033). Logistic regression analyses revealed that only younger age at the time of surgery was significantly associated with major adverse events (odds ratio 0.82; 95% CI 0.72-0.94, p = 0.003).

CONCLUSIONS

The incidence of sarcopenia, as assessed by preoperative chest CT, was low in pediatric patients undergoing total correction of TOF, and preoperative sarcopenia did not predict early postoperative major adverse events.

20-Year Experience With Repair of Pulmonary Atresia or Stenosis and Major Aortopulmonary Collateral Arteries

BACKGROUND

We have followed a consistent, albeit evolving, strategy for the management of patients with pulmonary atresia or severe stenosis and major aortopulmonary collateral arteries (MAPCAs) that aims to achieve complete repair with low right ventricular pressure by completely incorporating blood supply and relieving stenoses to all lung segments.

OBJECTIVES

The purpose of this study was to characterize our 20-year institutional experience managing patients with MAPCAs.

METHODS

We reviewed all patients who underwent surgery for MAPCAs and biventricular heart disease from November 2001 through December 2021.

RESULTS

During the study period, 780 unique patients underwent surgery. The number of new patients undergoing surgery annually was relatively steady during the first 15 years, then increased substantially thereafter. Surgery before referral had been performed in almost 40% of patients, more often in our recent experience than earlier. Complete repair was achieved in 704 patients (90%), 521 (67%) during the first surgery at our center, with a median right ventricular to aortic pressure ratio of 0.34 (25th, 75th percentiles: 0.28, 0.40). The cumulative incidence of mortality was 15% (95% CI: 12%-19%) at 10 years, with no difference according to era of surgery (P = 0.53). On multivariable Cox regression, Alagille syndrome (HR: 2.8; 95% CI: 1.4-5.7; P = 0.004), preoperative respiratory support (HR: 2.0; 95% CI: 1.2-3.3; P = 0.008), and palliative first surgery at our center (HR: 3.5; 95% CI: 2.3-5.4; P < 0.001) were associated with higher risk of death.

CONCLUSIONS

In a growing pulmonary artery reconstruction program, with increasing volumes and an expanding population of patients who underwent prior surgery, outcomes of patients with pulmonary atresia or stenosis and MAPCAs have continued to improve.

Genetic Risk Score Constructed from Polymorphisms in the VEGFA, TBX5, and SMAD7 Genes Provides Novel Insights into the Molecular Mechanisms of the Tetralogy of Fallot and Ventricular Septal Defect (Case-Control Study from the Pakistani Population)

Congenital heart defects are common and complex birth-defect malformations in developed and developing countries. It is a multifactorial disease that involves the interaction of either gene-gene or gene-environment. This comparative study was the first report on the genotypic-phenotypic correlation in the Pakistani population. The single nucleotide polymorphisms (SNPs) were further tested for association with maternal diabetes mellitus or hypertension. In addition, the cumulative genetic risk score (GRS) for low to moderately-associated SNPs was calculated for each study subject, which can ultimately guide us for better therapeutic options and prevention strategies. According to the predefined selection criteria, 376 subjects were recruited. The multiplex mini-sequencing genotyping technique opted for the cost-effective genotyping of selected loci. The association of variants with the disease was examined using logistic regression analysis. The statistical and graphical analysis was conducted using SPSS, Haploview, SNPStats, and GraphPad Prism. The results for all SNPs analysis suggested a nonsignificant association with overall congenital heart defect risk except rs3809923. However, interestingly on stratified analysis variants, rs3809923 and rs3809922 showed an association only with tetralogy of Fallot. The remaining risk factor analysis for maternal hypertension and diabetes mellitus association with SNPs were nonsignificant. The GRS was the first time constructed for this low to moderately-associated variants. Interestingly, the cumulative GRS was significantly different from the control group revealing the cumulative effect of these polymorphisms panel in patients. In conclusion, the use of GRS in the clinical setting can predict better risk association and patient outcomes.

Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part I: JACC State-of-the-Art Review

Patients with congenital heart disease associated with a higher risk for ventricular arrhythmias (VA) and sudden cardiac death (SCD) can be divided conceptually into those with discrete mechanisms for reentrant monomorphic ventricular tachycardia (VT) (Group A) and those with more diffuse substrates (Group B). Part I of this review addresses Group A lesions, which predominantly consist of tetralogy of Fallot and related variants. Well-defined anatomic isthmuses for reentrant monomorphic VT are interposed between surgical scars and the pulmonary or tricuspid annulus. The most commonly implicated critical isthmus for VT is the conal septum that divides subpulmonary from subaortic outlets. Programmed ventricular stimulation can be helpful in risk stratification. Although catheter ablation is not generally considered an alternative to the implantable cardioverter-defibrillator (ICD) for prevention of SCD, emerging data suggest that there is a subset of carefully selected patients who may not require ICDs after successful monomorphic VT ablation.

Mycobacteroides abscessus infection in a patient with tetralogy of Fallot

A 58-year-old woman with tetralogy of Fallot was referred to our hospital with a 2-month history of hemoptysis and low-grade fever. The sputum smear on admission showed positive results for acid-fast bacilli, and comparative genomic analysis of the cultured sputum confirmed Mycobacteroides abscessus subsp. abscessus infection. Long-term combination antimicrobial therapy gradually improved the patient's symptoms. Although non-tuberculous mycobacteria infection is rarely observed in patients with cyanotic congenital heart disease, a worldwide increase in non-tuberculous mycobacteria infections may increase the incidence of this rare combination.

Comparison of treatment strategies for neonates with tetralogy of Fallot and pulmonary atresia

OBJECTIVE

Neonates with tetralogy of Fallot and pulmonary atresia (TOF/PA) but no major aorta-pulmonary collaterals are dependent on the arterial duct for pulmonary blood flow and require early intervention, either by primary (PR) or staged repair (SR) with initial palliation (IP) followed by complete repair (CR). The optimal approach has not been established.

METHODS

Neonates with TOF/PA who underwent PR or SR were retrospectively reviewed from the Congenital Cardiac Research Collaborative. Outcomes were compared between PR and SR (IP + CR) strategies. Propensity scoring was used to adjust for baseline differences. The primary outcome was mortality. Secondary outcomes included complications, length of stay, cardiopulmonary bypass and anesthesia times, reintervention (RI), and pulmonary artery (PA) growth.

RESULTS

Of 282 neonates, 106 underwent PR and 176 underwent SR (IP: 144 surgical, 32 transcatheter). Patients who underwent SR were more likely to have DiGeorge syndrome and greater rates of mechanical ventilation before the initial intervention. Mortality was not significantly different. Duration of mechanical ventilation, inotrope use, and complication rates were similar. Cumulative length of stay, cardiopulmonary bypass, and anesthesia times favored PR (P ≤ .001). Early RI was more common in patients who underwent SR (rate ratio, 1.42; P = .003) but was similar after CR (P = .837). Conduit size at the time of CR was larger with SR. Right PA growth was greater with PR.

CONCLUSIONS

In neonates with TOF/PA, SR is more common in greater-risk patients. Accounting for this, SR and PR strategies have similar mortality. Perioperative morbidities, RI, and right PA growth generally favor PR, whereas SR allows for larger initial conduit implantation.

Prenatal diagnosis, management, and outcomes of fetuses with tetralogy of Fallot in China after prenatal counseling: a prospective cohort study

Objective

The study aimed to monitor fetuses with tetralogy of Fallot (TOF) after prenatal counseling and how it influenced the decision of parents to terminate the pregnancy.

Methods

Fetuses with isolated TOF diagnosed between January 2019 and December 2021 were prospectively enrolled. The follow-up period extended until termination or 6 months after the operation.

Results

Of the 1,026 fetuses diagnosed with cardiac defects, 129 were identified to have isolated TOF and completed the follow-up. A total of 55 (42.6%) fetuses were terminated, with larger maternal age (odds ratio: 0.893, 95% confidence interval: 0.806-0.989, P = 0.031) as the protective factor. The maternal anxiety score, gestational weeks, and pulmonary-to-aortic-diameter ratio lost significance in multivariate analysis. Subjectively, the two most common reasons for terminating the pregnancy were worries about the prognosis (41.8%) and concerns about the possible suffering of the unborn child (18.2%). The prenatal diagnosis was accurate in 73 of the 74 (98.6%) live births. Out of the 64 live births that underwent surgical repair in our center, 57 (89.1%) received primary repair, with a median age of 104 days, and 49 (76.6%) underwent valve-sparing repair. No perioperative death occurred.

Conclusions

Termination for fetuses with TOF remains common in China. Live births with TOF can be safely and effectively managed.

Unique Pulmonary Hypertensive Vascular Diseases Associated with Heart and Lung Developmental Defects

Although pediatric pulmonary hypertension (PH) shares features and mechanisms with adult PH, there are also some significant differences between the two conditions. Segmental PH is a unique pediatric subtype of PH with unclear and/or multifactorial pathophysiological mechanisms, and is often associated with complex congenital heart disease (CHD), pulmonary atresia with ventricular septal defect, and aortopulmonary collateral arteries. Some cases of complex CHD, associated with a single ventricle after Fontan operation, show pathological changes in the small peripheral pulmonary arteries and pulmonary vascular resistance similar to those observed in pulmonary arterial hypertension (PAH). This condition is termed as the pediatric pulmonary hypertensive vascular disease (PPHVD). Recent advances in genetics have identified the genes responsible for PAH associated with developmental defects of the heart and lungs, such as TBX4 and SOX17. Targeted therapies for PAH have been developed; however, their effects on PH associated with developmental heart and lung defects remain to be established. Real-world data analyses on the anatomy, pathophysiology, genetics, and molecular biology of unique PPHVD cases associated with developmental defects of the heart and lungs, using nationwide and/or international registries, should be conducted in order to improve the treatments and prognosis of patients with these types of pediatric PH.

Intravascular Lithotripsy for Severe RVOT Calcification to Optimize Transcatheter Pulmonary Valve Replacement

The presence of severe right ventricular outflow tract calcification may preclude safe and effective transcatheter pulmonary valve replacement in patients with pulmonary allograft stenosis owing to the risk of conduit tear and suboptimal annular expansion. Debulking calcium using intravascular lithotripsy within the right ventricular outflow tract may mitigate this risk and improve valve hemodynamics. (Level of Difficulty: Advanced.).

Management of tetralogy of Fallot in the pediatric intensive care unit

Tetralogy of Fallot (ToF) is one of the most common congenital cyanotic heart lesions and can present to a variety of health care professionals, including teams working in pediatric intensive care. Pediatric intensive care teams may care for a child with ToF pre-operatively, peri-operatively, and post-operatively. Each stage of management presents its own unique challenges. In this paper we discuss the role of pediatric intensive care in each stage of management.

Impaired Distensibility of the Proximal Aorta in Fetuses With Tetralogy of Fallot

Background Increased aortic wall stiffness, which even persists after repair, has been reported in patients with tetralogy of Fallot (TOF). We aimed to observe the distensibility of the ascending aorta and descending aorta in fetuses with TOF and explore its relation with aortic blood flow volume and aortic and pulmonary annular size. Methods and Results Twenty-three fetuses with TOF and 23 gestational age-matched normal fetuses were included in this prospective cross-sectional study. The distensibilities of the ascending aorta and descending aorta were assessed by aortic strain (AS), which was defined as follows: 100×(maximum internal diameter in the systolic phase-minimum internal diameter in the diastolic phase)/minimum internal diameter in the diastolic phase. The maximum internal diameter in the systolic phase and minimum internal diameter in the diastolic phase of the ascending aorta and descending aorta were measured by M-mode echocardiography. Associations between AS and aortic blood flow volume and aortic and pulmonary valve diameters were assessed in both groups. AS of the ascending aorta in TOF group was lower than that in controls (20.48%±4.19% versus 28.17%±4.54%; P<0.001), whereas there was no significant difference in the descending aorta. The multivariate regression model demonstrated that AS was significantly related to aortic valve size (P=0.014) and aortic blood flow volume (P=0.022) in fetuses with TOF, whereas only aortic blood flow volume was significantly correlated with AS in the control group (P=0.01). No significant association was found between AS and pulmonary valve size. Conclusions Impaired distensibility of proximal aorta was observed in fetuses with TOF. Both intrinsic abnormalities of the aortic wall and aortic volume overload probably play roles in the altered aortic distensibility.

Machine Learning for Prediction of Adverse Cardiovascular Events in Adults With Repaired Tetralogy of Fallot Using Clinical and Cardiovascular Magnetic Resonance Imaging Variables

BACKGROUND

Existing models for prediction of major adverse cardiovascular events (MACE) after repair of tetralogy of Fallot have been limited by modest predictive capacity and limited applicability to routine clinical practice. We hypothesized that an artificial intelligence model using an array of parameters would enhance 5-year MACE prediction in adults with repaired tetralogy of Fallot.

METHODS

A machine learning algorithm was applied to 2 nonoverlapping, institutional databases of adults with repaired tetralogy of Fallot: (1) for model development, a prospectively constructed clinical and cardiovascular magnetic resonance registry; (2) for model validation, a retrospective database comprised of variables extracted from the electronic health record. The MACE composite outcome included mortality, resuscitated sudden death, sustained ventricular tachycardia and heart failure. Analysis was restricted to individuals with MACE or followed ≥5 years. A random forest model was trained using machine learning (n=57 variables). Repeated random sub-sampling validation was sequentially applied to the development dataset followed by application to the validation dataset.

RESULTS

We identified 804 individuals (n=312 for development and n=492 for validation). Model prediction (area under the curve [95% CI]) for MACE in the validation dataset was strong (0.82 [0.74-0.89]) with superior performance to a conventional Cox multivariable model (0.63 [0.51-0.75]; P=0.003). Model performance did not change significantly with input restricted to the 10 strongest features (decreasing order of strength: right ventricular end-systolic volume indexed, right ventricular ejection fraction, age at cardiovascular magnetic resonance imaging, age at repair, absolute ventilatory anaerobic threshold, right ventricular end-diastolic volume indexed, ventilatory anaerobic threshold % predicted, peak aerobic capacity, left ventricular ejection fraction, and pulmonary regurgitation fraction; 0.81 [0.72-0.89]; P=0.232). Removing exercise parameters resulted in inferior model performance (0.75 [0.65-0.84]; P=0.002).

CONCLUSIONS

In this single-center study, a machine learning-based prediction model comprised of readily available clinical and cardiovascular magnetic resonance imaging variables performed well in an independent validation cohort. Further study will determine the value of this model for risk stratification in adults with repared tetralogy of Fallot.