Bioptome-assisted blunt dissection facilitates endovascular retrieval of a chronically embolized stent.

We present a 19-year-old female with history of d-transposition of the great arteries status post-arterial switch operation.

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.

Management of congenitally corrected transposition from fetal diagnosis to adulthood.

INTRODUCTION: Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart defect characterized by atrioventricular and ventriculo-arterial discordance. CcTGA can be diagnosed at any stage of life. The natural history of the disease depends on concomitant anomalies present in most of the cases, progression of systemic ventricular dysfunction and conduction disturbances. AREAS COVERED: This review describes diagnosis of the anomaly and summarizes the current knowledge on etiology and prognosis in ccTGA patients. Furthermore, interventional and pharmacological approaches to ccTGA management are discussed. The areas requiring further research are highlighted. EXPERT OPINION: Although advances in diagnosis and treatment continue to improve outcomes for ccTGA, patients are burdened with significant morbidity and mortality. Optimal approaches to surgical management of the anomaly, as well as prevention and management of heart failure, are still not established. Future research should focus on the long-term effect of anatomic repair, potential benefits of novel pharmacological strategies for heart failure therapy, and the optimal mode of pacing in ccTGA patients. However, the issues might be difficult to address due to rarity of the disease and its heterogenous clinical presentation. As the life-expectancy of ccTGA patients improves, acquired cardiovascular disorders will become another serious concern.

Corrected Transposition of Great Arteries with Cor Triatriatum and Atrial Septal Defect-Case Report.

A 37-year-old male patient with corrected transposition of great arteries (ccTGA) with cor triatriatum sinister (CTS), left superior vena cava, and atrial septal defects is reported in our case. None of these impacted the patient's growth or development, nor daily work until age 33. Later, the patient developed symptoms of obvious impaired heart function, which improved after medical treatment. However, the symptoms reappeared and gradually worsened two years later, and we decided to treat it with surgery. In this case, we selected tricuspid mechanical valve replacement, cor triatriatum correction, and atrial septal defect repair. During the follow-up of five years, the patient had no obvious symptoms, ECG did not change significantly from five years ago, and the cardiac color Doppler ultrasound showed RVEF 0.51.

Familial Recurrence Patterns in Congenitally Corrected Transposition of the Great Arteries: An International Study.

BACKGROUND: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns. METHODS: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands. RESULTS: Laterality defects and atrioventricular block at diagnosis were observed in 29.9% and 9.3%, respectively. ccTGA was associated with primary ciliary dyskinesia in 11 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (28.4%), laterality defects (13.6%), and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and dextro-transposition of the great arteries, and 9 familial co-segregation of ccTGA and laterality defects. In one family co-segregation of ccTGA, dextro-transposition of the great arteries and heterotaxy syndrome in 3 distinct relatives was found. In another family, twins both displayed ccTGA and primary ciliary dyskinesia. CONCLUSIONS: ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, dextro-transposition of the great arteries, laterality defects and in some cases primary ciliary dyskinesia, strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

Associations between IL-1α, IL-1ß, TNFα, and IL-6 variations, and susceptibility to transposition of the great arteries.

BACKGROUND: To evaluate the relationship between IL-1α -889C/T (rs1800587), IL-1ß -511C > T (rs16944), TNFα -308G > A (rs1800629), TNFα -238G > A (rs361525), IL-6 -174G > C (rs1800795), and IL-6 -572G > C (rs1800796) polymorphisms and the susceptibility to transposition of the great arteries (TGA). METHODS: A prospective analysis was performed on mothers whose newborns were diagnosed as having TGA. For each case of TGA, a mother who gave birth to a healthy neonate in the same period was randomly selected for the control group. The sample size was calculated before planning the study with 80% power and 5% alpha. RESULTS: Twenty-seven mothers whose newborn had TGA anomalies (group 1) and 27 mothers whose newborn had no TGA (group 2) were included in the study. There were no significant differences between the groups in terms of maternal age, pregestational body mass index, gestational age at birth and infant sex (p > 0.05). The genotype and allele distributions of IL-1α -889C/T (rs1800587), IL-1ß -511C > T (rs16944), TNFα -308G > A (rs1800629), TNFα -238G > A (rs361525), IL-6 -174G > C (rs1800795) and IL-6 -572G > C (rs1800796) gene variants were not different between the two groups (p > 0.05). CONCLUSIONS: There was no relation between IL-1α, IL-1ß, IL-6, and TNFα promoter gene polymorphisms and TGA occurrence in our study group. TRIAL REGISTRATION: This present prospective case-control study was conducted in Baskent University Hospital, Ankara, Turkey, between May 2020 and November 2021. Ethical approval was obtained from the university's Clinical Research Ethics Commitee (No: KA20/211) in accordance with the Declaration of Helsinki.

Management of Hypertrophic Cardiomyopathy in a Newborn with Dextro-Transposition of the Great Arteries.

Impaired maternal glucose metabolism during pregnancy can have significant effects on the cardiovascular system of the developing fetus. Early in pregnancy the teratogenic effects may lead to structural heart defects, while later in gestation a form of hypertrophic cardiomyopathy can develop due to overgrowth driven by fetal hyperinsulinism. We describe an infant with the uncommon combination of both dextro-transposition of the great arteries and hypertrophic cardiomyopathy. We emphasize the importance of a longitudinal multi-disciplinary approach, from fetal diagnosis to post-operative management, that allowed for an excellent outcome in this rare combination of severe cardiac malformations.

Does a prenatal diagnosis affect mortality and morbidity for neonatal arterial switch operation.

BACKGROUND: The effect of prenatal diagnosis on prognosis in patients with transposition of the great arteries is not clear. In this study, we compared the outcomes after arterial switch operation. METHODS: Outcome of 112 patients who had arterial switch operation in the neonatal period were analysed. The patients were divided into two groups: those who had prenatal diagnosis (Group 1; n = 34) and those who did not (Group 2; n = 78). The patients were also classified based on their diagnosis: simple transposition, transposition with ventricular septal defect and/or aortic arch hypoplasia, and Taussig-Bing anomaly. RESULTS: In Group 1, the C-section delivery rate was higher (82% vs. 44%; p = 0.004), and it was observed that patients in Group 1 were more often intubated upon admission to the neonatal ICU (38% vs. 9%; p = 0.005). No differences were found between the two groups in terms of operation time, cardiopulmonary bypass time, post-operative invasive respiratory support duration, or extracorporeal membrane oxygenation support. It was observed that those who had Taussig-Bing anomaly had a higher mortality. CONCLUSIONS: Timely treatment have a positive effect on neonatal mortality and morbidity. That's why all families with prenatal diagnosis of critical CHD should be recommended to have the delivery in a tertiary care hospital. Although it could not be demonstrated in this study, prenatal diagnosis has a potential to improve surgical results especially in countries or cities, which does not have enough resources for transfer and surgical units. Further efforts are needed to improve prenatal screening programmes.

Medication in adults after atrial switch for transposition of the great arteries: clinical practice and recommendations.

AIMS: Heart failure is the main threat to long-term health in adults with transposition of the great arteries (TGA) corrected by an atrial switch operation (AtrSO). Current guidelines refrain from recommending heart failure medication in TGA-AtrSO, as there is insufficient data to support the hypothesis that it is beneficial. Medication is therefore prescribed based on personal judgements. We aimed to evaluate medication use in TGA-AtrSO patients and examine the association of use of renin-angiotensin-aldosterone system (RAAS) inhibitors and ß-blockers with long-term survival. METHODS AND RESULTS: We identified 150 TGA-AtrSO patients [median age 30 years (interquartile range 25-35), 63% male] included in the CONCOR registry from five tertiary medical centres with subsequent linkage to the Dutch Dispensed Drug Register for the years 2006-2014. Use of RAAS inhibitors, ß-blockers, and diuretics increased with age, from, respectively, 21% [95% confidence interval (CI) 14-40], 12% (95% CI 7-21), and 3% (95% CI 2-7) at age 25, to 49% (95% CI 38-60), 51% (95% CI 38-63), and 41% (95% CI 29-54) at age 45. Time-varying Cox marginal structural models that adjusted for confounding medication showed a lower mortality risk with use of RAAS inhibitors and ß-blockers in symptomatic patients [hazard ratio (HR) = 0.13 (95% CI 0.03-0.73); P = 0.020 and HR = 0.12 (95% CI 0.02-0.17); P = 0.019, respectively]. However, in the overall cohort, no benefit of RAAS inhibitors and ß-blockers was seen [HR = 0.93 (95% CI 0.24-3.63); P = 0.92 and HR = 0.98 (0.23-4.17); P = 0.98, respectively]. CONCLUSION: The use of heart failure medication is high in TGA-AtrSO patients, although evidence of its benefit is limited. This study showed lower risk of mortality with use of RAAS inhibitors and ß-blockers in symptomatic patients only. These findings can direct future guidelines, supporting use of RAAS inhibitors and ß-blockers in symptomatic, but not asymptomatic patients.

Geographic Distribution of Congenital Heart Disease: A Single Surgical Center Experience.

OBJECTIVE: To determine presence of spatial clustering or dispersion of pre and postnatally detected hypoplastic left heart syndrome (HLHS) and d-transposition of the great arteries (TGA) cases. STUDY DESIGN: This retrospective study examined all patients with a prenatal or postnatal diagnosis of HLHS or TGA who had an initial visit or hospitalization at our tertiary care center over a 5-year period from 2012 to 2016 (n = 105). Using geographic information systems software, the nearest neighbor ratio (NNR) tool was used to determine whether statistically significant clustering or dispersion occurred. RESULTS: Geographic clustering was observed among prenatally diagnosed pooled cases of HLHS and TGA and all total cases (NNR = 0.73 and 0.66, respectively), but not postnatally detected cases (NNR = 1.08). Notably, there was significant dispersion of postnatally detected TGA cases (NNR = 1.22) There was no pattern for prenatally detected TGA or HLHS when analyzed individually. CONCLUSIONS: The spatial distribution of HLHS and TGA is not random; these conditions occur in geographic clusters. Clustering of all patients in the study population and dispersion of postnatal diagnosis of TGA represent opportunities for improved delivery of fetal cardiac care.

Baffle Complications in Adults After Atrial Switch for Transposition of the Great Arteries.

BACKGROUND: Baffle complications, ie, leakage or stenosis, after an atrial switch operation (AtrSO) for transposition of the great arteries (TGA) are difficult to detect with the use of routine transthoracic echocardiography (TTE). We examined baffle interventions and the prevalence of baffle complications. METHODS: This dual-centre study followed TGA-AtrSO patients for the occurrence of baffle interventions. In addition, in 2017-2019, prevalence of baffle complications was determined in patients undergoing routine contrast-enhanced (CE) TTE including various hemodynamic conditions and computed tomography (CT). Baffle leaks were defined as right-to-left shunting on CE-TTE and baffle stenosis as a systemic venous baffle diameter of < 10 mm on CT. RESULTS: In total, 67 TGA-AtrSO patients were followed to a median age of 38 (interquartile range 34-42) years, for a median of 9 (6-13) years. Baffle interventions were documented in 24 patients (36%). Cumulative risk of baffle interventions was 25% after 15 years of follow-up. Prevalence of baffle complications was determined in 29/67 patients. In total, 4 (14%) had patent baffles, 11 (38%) had leakage only, 5 (17%) had stenosis only, and 9 (31%) had both, while 24/29 (84%) were asymptomatic. Although baffle leaks were not associated with clinical characteristics, peak work rate during exercise TTE was lower in patients with vs without stenosis (89 ± 24 W vs 123 ± 21 W; P < 0.001). CONCLUSIONS: Baffle complications are common in TGA-AtrSO. The cumulative risk of baffle interventions was 25% after 15 years of follow-up. CE-TTE uncovered asymptomatic baffle leakage in the majority of patients, especially with examination during exercise. CT revealed baffle stenosis in almost half of the patients, which was associated with decreased exercise tolerance. Awareness of these findings may alter clinical follow-up.

Clinical RNA sequencing confirms compound heterozygous intronic variants in RYR1 in a patient with congenital myopathy, respiratory failure, neonatal brain hemorrhage, and d-transposition of the great arteries.

BACKGROUND: Defects in the RYR1 (OMIM#180901) gene lead to Ryanodine receptor type 1-related myopathies (RYR1-RM); the most common subgroup of congenital myopathies. METHODS: Congenital myopathy presents a diagnostic challenge due to the need for multiple testing modalities to identify the many different genetic etiologies. In this case, the patient remained undiagnosed after whole-exome sequencing (WES), chromosomal microarray, methylation analysis, targeted deletion and duplication studies, and targeted repeat expansion studies. Clinical whole-genome sequencing (WGS) was then pursued as part of a research study to identify a diagnosis. RESULTS: WGS identified compound heterozygous RYR1 intronic variants, RNA sequencing confirmed both variants to be pathogenic causing RYR1-RM in a phenotype of severe congenital hypotonia with respiratory failure from birth, neonatal brain hemorrhage, and congenital heart disease involving transposition of the great arteries. CONCLUSION: While there is an ongoing debate about the clinical superiority of WGS versus WES for patients with a suspected genetic condition, this scenario highlights a weakness of WES as well as the added cost and delay in diagnosis timing with having WGS follow WES or even ending further genetic testing with a negative WES. While knowledge gaps still exist for many intronic variants, transcriptome analysis provides a way of validating the resulting dysfunction caused by these variants and thus allowing for appropriate pathogenicity classification. This is the second published case report of a patient with pathogenic intronic variants in RYR1-RM, with clinical RNA testing confirming variant pathogenicity and therefore the diagnosis suggesting that for some patients careful analysis of a patient's genome and transcriptome are required for a complete genetic evaluation. The diagnostic odyssey experienced by this patient highlights the importance of early, rapid WGS.

Ventricular and atrial function and deformation is largely preserved after arterial switch operation.

OBJECTIVE: To test the hypothesis that ventricular and atrial function are different between patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) and healthy controls. METHODS: 103 consecutive patients with TGA (median age: 16.7 years, 4.3-39.6 years, 71.8% male) were compared with 77 controls (median age: 15.4 years, 6.3-43.2 years, 66.2% male). Biventricular and biatrial function were assessed using standard cardiovascular magnetic resonance (CMR) techniques and feature tracking. Group comparison was performed with conventional non-parametrical statistics and machine learning methods to find the variables most discriminative between patients and controls. These variables were used to build a multivariable logistic regression model to assess the case-control status. RESULTS: Markers of left and right ventricular function (LV; RV) (ejection fraction, MAPSE, TAPSE, LV long-axis strain) as well as LV global longitudinal (-20.7 (-24.1; -17.9) vs -23.7 (-26.1; -21.6), p<0.001), circumferential (-29.4 (-32.2; -26.5) vs -30.5 (-33.6; 29), p=0.001) and atrial longitudinal strain (left atrium (LA): 23.3 (18.6; 28.8) vs 36.7 (30.7; 44), p<0001; right atrium: 21.7 (18.2; 27.8) vs 34.9 (26.9; 40.3), p<0.001) were reduced in patients compared with controls using non-parametrical testing. The logistic regression model including the most discriminative variables from univariate and machine learning analysis demonstrated significant differences between patients and controls only for TAPSE and LA global longitudinal strain. CONCLUSIONS: Biventricular and biatrial function are largely preserved after ASO for TGA. Using a comprehensive CMR protocol along with statistical machine learning methods and a regression approach, only RV longitudinal function and LA function are significantly impaired.

Management considerations in the adult with surgically modified d-transposition of the great arteries.

Dextro-transposition of the great arteries (D-TGA) has undergone a significant evolution in surgical repair, leading to survivors with vastly different postsurgical anatomy which in turn guides their long-term cardiovascular morbidity and mortality. Atrial switch repair survivors are limited by a right ventricle in the systemic position, arrhythmia and atrial baffles prone to obstruction or leak. Functional assessment of the systemic right ventricle is complex, requiring multimodality imaging to include specialised echocardiography and cross-sectional imaging (MRI and CT). In the current era, most neonates undergo the arterial switch operation with increasing understanding of near-term and long-term outcomes specific to their cardiac anatomy. Long-term observations of the Lecompte manoeuvre or coronary stenoses following transfer continue, with evolving understanding to improve surveillance. Ultimately, an understanding of postsurgical anatomy, specialised imaging techniques and interventional and electrophysiological procedures is essential to comprehensive care of D-TGA survivors.

Clinical Course Long After Atrial Switch: A Novel Risk Score for Major Clinical Events.

Background Patients with transposition of the great arteries corrected by an atrial switch operation experience major clinical events during adulthood, mainly heart failure (HF) and arrhythmias, but data on the emerging risks remain scarce. We assessed the risk for events during the clinical course in adulthood, and provided a novel risk score for event-free survival. Methods and Results This multicenter study observed 167 patients with transposition of the great arteries corrected by an atrial switch operation (61% Mustard procedure; age, 28 [interquartile range, 24-36] years) for 13 (interquartile range, 9-16) years, during which 16 (10%) patients died, 33 (20%) had HF events, defined as HF hospitalizations, heart transplantation, ventricular assist device implantation, or HF-related death, and 15 (9%) had symptomatic ventricular arrhythmias. Five-year risk of mortality, first HF event, and first ventricular arrhythmia increased from 1% each at age 25 years, to 6% (95% CI, 4%-9%), 23% (95% CI, 17%-28%), and 5% (95% CI, 2%-8%), respectively, at age 50 years. Predictors for event-free survival were examined to construct a prediction model using bootstrapping techniques. A prediction model combining age >30 years, prior ventricular arrhythmia, age >1 year at repair, moderate or greater right ventricular dysfunction, severe tricuspid regurgitation, and mild or greater left ventricular dysfunction discriminated well between patients at low (<5%), intermediate (5%-20%), and high (>20%) 5-year risk (optimism-corrected C-statistic, 0.86 [95% CI, 0.82-0.90]). Observed 5- and 10-year event-free survival rates in low-risk patients were 100% and 97%, respectively, compared with only 31% and 8%, respectively, in high-risk patients. Conclusions The clinical course of patients undergoing atrial switch increasingly consists of major clinical events, especially HF. A novel risk score stratifying patients as low, intermediate, and high risk for event-free survival provides information on absolute individual risks, which may support decisions for pharmacological and interventional management.

Regional Brain Growth Trajectories in Fetuses with Congenital Heart Disease.

OBJECTIVE: Congenital heart disease (CHD) is associated with abnormal brain development in utero. We applied innovative fetal magnetic resonance imaging (MRI) techniques to determine whether reduced fetal cerebral substrate delivery impacts the brain globally, or in a region-specific pattern. Our novel design included two control groups, one with and the other without a family history of CHD, to explore the contribution of shared genes and/or fetal environment to brain development. METHODS: From 2014 to 2018, we enrolled 179 pregnant women into 4 groups: "HLHS/TGA" fetuses with hypoplastic left heart syndrome (HLHS) or transposition of the great arteries (TGA), diagnoses with lowest fetal cerebral substrate delivery; "CHD-other," with other CHD diagnoses; "CHD-related," healthy with a CHD family history; and "optimal control," healthy without a family history. Two MRIs were obtained between 18 and 40 weeks gestation. Random effect regression models assessed group differences in brain volumes and relationships to hemodynamic variables. RESULTS: HLHS/TGA (n = 24), CHD-other (50), and CHD-related (34) groups each had generally smaller brain volumes than the optimal controls (71). Compared with CHD-related, the HLHS/TGA group had smaller subplate (-13.3% [standard error = 4.3%], p < 0.01) and intermediate (-13.7% [4.3%], p < 0.01) zones, with a similar trend in ventricular zone (-7.1% [1.9%], p = 0.07). These volumetric reductions were associated with lower cerebral substrate delivery. INTERPRETATION: Fetuses with CHD, especially those with lowest cerebral substrate delivery, show a region-specific pattern of small brain volumes and impaired brain growth before 32 weeks gestation. The brains of fetuses with CHD were more similar to those of CHD-related than optimal controls, suggesting genetic or environmental factors also contribute. ANN NEUROL 2021;89:143-157.

Fetal Umbilical Arterial Pulsatility Correlates With 2-Year Growth and Neurodevelopmental Outcomes in Congenital Heart Disease.

BACKGROUND: Children with congenital heart disease (CHD) are at risk of adverse long-term neurodevelopmental outcomes, believed to be, in part, secondary to prenatal insults. Placental pathology and altered fetal middle cerebral arterial (MCA) flow suggestive of brain sparing have been documented in fetal CHD. In the present study we investigated the relationship between MCA and umbilical arterial (UA) flow patterns in fetal transposition of the great arteries (d-TGA) and hypoplastic left heart syndrome (HLHS) and growth and 2-year neurodevelopmental outcomes. METHODS: We included children with d-TGA and HLHS who had third-trimester fetal echocardiograms between 2004 and 2014, at which time umbilical artery (UA) and MCA pulsatility indices (PIs) were measured, and who underwent 2-year growth and neurodevelopmental assessments. RESULTS: We identified 24 children with d-TGA and 36 with HLHS. Mean age at fetal echocardiography was 33.8 ± 3.5 weeks. At 2-year follow-up, head circumference z score (standard deviation [SD]) was -0.09 (1.07) and 0.17 (1.7) for the d-TGA and HLHS groups, respectively. Bayley III mean (SD) cognitive, language, and motor scores were 97.7 (10.8), 94.7 (13.4), and 98.6 (8.6) for the d-TGA group and 90.3 (13.9), 87.2 (17.5), and 85.3 (16.2) for the HLHS group. On multivariate linear regression analysis, UA-PI was associated (effect sizes [95% CI]) with length (-1.45 [-2.7, -0.17], P = 0.027), weight (-1.46 [-2.6 to -0.30], P = 0.015) and cognitive scores (-14.86 [-29.95 to 0.23], P = 0.05) at 2 years of age. MCA PI showed no statistically significant correlation. CONCLUSIONS: In fetal d-TGA and HLHS, a higher UA-PI in the third trimester, suggestive of placental insufficiency-but not MCA-PI-is associated with worse 2-year growth and neurodevelopment.

Prenatal diagnosis and planned peripartum care improve perinatal outcome of fetuses with transposition of the great arteries and intact ventricular septum in low-resource settings.

OBJECTIVE: To report on the feasibility of establishing a regional prenatal referral network for critical congenital heart defects (CHDs) and its impact on perinatal outcome of fetuses with transposition of the great arteries and intact ventricular septum (TGA-IVS) in low-resource settings. METHODS: This was a retrospective study of consecutive fetuses with a diagnosis of TGA-IVS between January 2011 and December 2019 in Kochi, Kerala, India. A regional network for prenatal diagnosis and referral of patients with critical CHDs was initiated in 2011. Pregnancy and early neonatal outcomes were reported. The impact of the timing of diagnosis (prenatal or after birth) on age at surgery, perinatal mortality and postoperative recovery was evaluated. RESULTS: A total of 82 fetuses with TGA-IVS were included. Diagnosis typically occurred later on in gestation, at a median of 25 (interquartile range (IQR), 21-32) weeks. The majority (78.0%) of affected pregnancies resulted in live birth, most (84.4%) of which occurred in a specialist pediatric cardiac centers. Delivery in a specialist center, compared with delivery in a local maternity center, was associated with a significantly higher rate of surgical correction (98.1% vs 70.0%; P = 0.01) and overall lower neonatal mortality (3.7% vs 50%; P = 0.001). The proportion of cases undergoing arterial switch operation after prenatal diagnosis of TGA-IVS increased significantly, along with the prenatal detection rate, over the study period (2011-2015, 11.1% vs 2016-2019, 29.4%; P = 0.001). Median age at surgery was significantly lower in the prenatally diagnosed group than that in the postnatally diagnosed group (4 days (IQR, 1-23 days) vs 10 days (IQR, 1-91 days); P < 0.001). There was no significant difference in postoperative mortality (2.0% vs 3.6%; P = 0.49) between the two groups. CONCLUSIONS: This study demonstrates the feasibility of creating a network for prenatal diagnosis and referral of patients with critical CHDs, such as TGA, in low-resource settings, that enables planned peripartum care in specialist pediatric cardiac centers and improved neonatal survival. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.