# Long-Term Outcome Following Prenatal Diagnosis of Transposition of the Great Arteries

## TL;DR

Prenatal diagnosis of d-TGA leads to good survival and outcomes similar to postnatal diagnosis after arterial switch surgery.

## Contribution

The study provides detailed long-term outcomes for prenatally diagnosed d-TGA patients to support prenatal counseling.

## Key findings

- 92.5% survival rate in prenatally diagnosed d-TGA patients after arterial switch operation.
- Reintervention rates were 9.2% in prenatally diagnosed patients, not significantly different from postnatal cases.
- Neurological and behavioral issues affected about 1 in 20 prenatally diagnosed patients.

## Abstract

Outcomes following the arterial switch operation (ASO) are well documented. Survival and long-term morbidity for fetuses diagnosed with dextro-transposition of the great arteries (d-TGA) are less reported. We aimed to document survival, reinterventions and morbidity for prenatally diagnosed d-TGA to inform prenatal counseling. Fetuses with d-TGA with or without ventricular septal defect (VSD) diagnosed between 1995 and 2022 at our institution were reviewed. Outcomes were compared to postnatally diagnosed patients undergoing intervention during the same era. Two hundred and seven fetuses were diagnosed resulting in 201 livebirths, 2 intrauterine demise, and 4 pregnancy terminations. There were 137 (68.2%) with isolated d-TGA and 64 (31.8%) with d-TGA-VSD. Median birthweight 3.21 kg (IQR 2.94–3.5 kg), and median birth gestation 38 weeks (IQR 38–39). Preoperative balloon atrial septostomy (BAS) was performed in 126/201(62.7%). No patients died prior to BAS. Three died before ASO following BAS. ASO was performed in 198/201(98.5%) with 45/198(22.7%) having concomitant VSD closure. Thirty-day survival for ASO was 95.5%. Survival over the study period was 186/201(92.5%). During the same period, 91 infants were referred for surgery with postnatal diagnosis, and 90 underwent ASO. There was no significant difference in 30-day or long-term survival following ASO according to timing of diagnosis. Three prenatally diagnosed patients undergoing the ASO were lost to follow up. There was no significant difference in reintervention rates (prenatal: 18/195 (9.2%); postnatal: 12/86 (13.9%) p = 0.24). Morbidity in prenatally diagnosed patients included myocardial dysfunction 3/195(1.5%), pulmonary hypertension 1/195(0.5%), supraventricular tachycardia 3/195(1.5%), neurological morbidity 9/195(4.6%), and autism 11/195(5.6%), and none were statistically different to the postnatal group. Survival following prenatal diagnosis of d-TGA is good. In the prenatally diagnosed cohort there were no deaths prior to BAS. Three died after BAS, with one of these deaths attributable to newborn hypoxia between BAS and ASO. Following ASO, most patients survive into third decade following prenatal diagnosis. Reintervention occurred in 9.2%. Neurological and behavioral morbidity affected approximately 1 in 20 patients. Outcomes for those with prenatal diagnosis of d-TGA are comparable with the patients that undergo ASO following postnatal diagnosis, but this excludes patients with a postnatal diangosis who did not survive to cardiac intervention. This data will be helpful for prenatal counseling.

The online version contains supplementary material available at 10.1007/s00246-025-03939-w.