Congenitally Corrected Transposition of the Great Arteries: Fetal Diagnosis, Associations, and Postnatal Outcome: A Fetal Heart Society Research Collaborative Study.

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Congenitally Corrected Transposition of the Great Arteries: Fetal Diagnosis, Associations, and Postnatal Outcome: A Fetal Heart Society Research Collaborative Study.

Cohen J, Arya B, Caplan R, Donofrio MT, Ferdman D, Harrington JK, Ho DY, Hogan W, Hornberger LK, Jhaveri S, Killen SAS, Lindblade CL, Michelfelder E, Moon-Grady AJ, Patel S, Quezada E, Ronai C, Sanchez Mejia AA, Schidlow DN, Stiver C, Thakur V, Srivastava S.J Am Heart Assoc. 2023 Jun 6;12(11):e029706. doi: 10.1161/JAHA.122.029706.

Take home points:

  • Genetic abnormalities and extracardiac anomalies occurred in ≈6%.
  • Associated defects are common with isolated congenitally corrected transposition of the great arteries in only 22%, and fetal atrioventricular block occurred in 11% and is a risk factor for fetal death (10.5%).
  • Serial fetal echocardiograms are important given that hemodynamic progression. Diagnostic change were common, with most common changes being an increase in tricuspid regurgitation or pulmonary outflow tract obstruction.
  • Overall risk of fetal death was low (1.5%) and short-term outcomes good with death/transplant by 1year of ≈7%, with risk factors including fetal tricuspid regurgitation (>mild), any arrhythmia, aortic obstruction, and worsening hemodynamics on serial echocardiograms.
Manoj Gupta

Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch.

Introduction:

Fetal diagnosis of congenitally corrected transposition of the great arteries (ccTGA) has been increasingly reported; however, predictors of clinical outcomes remain underexplored.  CcTGA is characterized by atrioventricular and ventriculoarterial discordance. Associated cardiac defects are common, particularly ventricular septal defects (VSD), pulmonary outflow tract obstruction, tricuspid valve (TV) abnormalities, abnormal cardiac position (dextro-mesocardiac), and aortic arch abnormalities. Rhythm abnormalities are also important associations, particularly atrioventricular block (AVB) and supraventricular tachycardia (SVT).

Cardiac Pathology on First and Serial Fetal Echocardiography

Abnormal cardiac position was noted in 67 (32.7%), with 39 (19.0%) fetuses having dextrocardia (34 with situs solitus and 5 situs inversus). The most common associated defects were VSD, pulmonary outflow tract obstruction, and TV structural abnormalities. TV abnormalities were less common in situs inversus, with none of the 15 situs inversus {I,D,D} patients having a TV structural abnormality (P=0.045).

Fetal AVB of any degree was diagnosed in 23 (11.3%): 22 on initial fetal echocardiogram and 1 on follow-up. Gestational age at AVB diagnosis was a median of 25 (IQR, 23–28, full range, 20–37) weeks. Patients with isolated ccTGA were more likely to have fetal AVB when compared with those with associated intracardiac defects (OR, 2.8 [95% CI, 1.1–7.1], P=0.03)

Postnatal Clinical Course

Postnatal clinical data for the 158 live births. By last follow-up, 103 (65%) patients had undergone surgical intervention. Of the 55 (35%) patients who did not have surgery by last follow-up, 28 had isolated ccTGA, 10 had ccTGA with VSD, 9 had ccTGA with VSD and pulmonary outflow obstruction, 4 had ccTGA with pulmonary outflow obstruction, 2 had ccTGA and Ebstein anomaly, and 2 died before intervention. RV failure requiring medication or hospitalization at any time was noted in 21 (14.2%) patients. Of these, 4 had isolated ccTGA (2 of whom had mild TR with normal valve morphology on first fetal echocardiogram). Anatomic repair was performed in 43 (27.2%) patients and was more common than physiologic repair, which was performed in 8 (5.1%) patients. Twenty-four patients had SV palliation at last follow-up. All these patients were thought to be candidates for 1.5- or 2-ventricle repair on first fetal echocardiogram.

Postnatal AVB was present in 43 patients (28.4%) by most recent follow-up. Seventeen of these patients had prenatal AVB, and 26 developed AVB postnatally. Of those who developed AVB postnatally, 8 were spontaneous (median age of 30months, IQR, 5–117months, full range, 0.5–450months), and 18 were associated with a procedure. Procedures included 6 with double switch operations (Senning atrial switch with an arterial switch) with VSD closure, 6 with Senning/Rastelli, 1 with Senning/ Nikaidoh, 1 with double switch without VSD closure, 2 with VSD closure, 1 with a pulmonary artery band, and 1 with cardiac catheterization. There were 3 patients with first-degree AVB, none of which progressed.

Preexcitation on ECG was noted in 8 (5.3%) patients; of these, 3 had tachycardia by last follow-up. Patients with a TV structural abnormality were more likely to have preexcitation on ECG (OR, 4.9 [95% CI, 1.2–24.9], P=0.035). There were 11 patients listed for heart transplantation: 6 for RV failure, 3 for left ventricular failure, 1 for severe TR, and 1 with bilateral restrictive physiology.

DISCUSSION

This study suggests that ccTGA is associated with a low rate of FD (1.5%) and a low rate of mortality or need for heart transplantation within the first year of life (occurring in <7%). Cardiac pathology conferring a higher risk of mortality on univariable analysis included mild or greater TR, any fetal arrhythmia, aortic outflow obstruction, pulmonary atresia, and the composite of worsening RV function, TR, or pericardial effusion in utero. Fetal AVB, which occurred in 11.3%, and observed most in isolated ccTGA, was an important risk factor for FD (FD occurred in 11% of those with fetal AVB).

Conclusions

This large multicenter study elucidates the spectrum and clinical outcome of fetal ccTGA, defining prenatal factors associated with worse outcomes. Associated cardiac lesions and arrhythmias are common in fetuses with ccTGA, whereas genetic syndromes and extracardiac defects are not. This study suggests overall good short-term outcomes, with poor outcome most associated with fetal TR, rhythm abnormalities, aortic outflow tract obstruction, pulmonary atresia, or worsening hemodynamics on serial prenatal assessment. Serial fetal echocardiography is important given the risks of hemodynamic progression, and it permits further detailed assessment of the cardiac structures, enhancing diagnostic accuracy. These findings can inform prenatal counseling as well as prenatal follow-up and delivery planning.

Pediatric Cardiac Professionals