Accuracy of prenatal echocardiographic diagnosis and prognosis of fetuses with conotruncal anomalies.

OBJECTIVES: The purpose of the study was to determine the accuracy of the prenatal echocardiographic diagnosis and prognosis of fetuses with conotruncal anomalies.

BACKGROUND: The accuracy of prenatal echocardiographic diagnoses of cardiac lesions has been reported, but no previous reports specifically address fetal conotruncal anomalies.

METHODS: Medical records of 61 fetuses, in which a fetal diagnosis of a conotruncal anomaly was made, were reviewed. Disease entities included were tetralogy of Fallot (TOF), double outlet right ventricle (DORV), transposition of the great arteries (TGA), and truncus arteriosus (TA).

RESULTS: Fetal diagnosis was established at a median of 24.5 weeks' gestation. Termination of pregnancy was chosen in 31% (19/61) of cases. Postnatal assessment of the diagnosis was not obtained in 12 cases. Excluding two sets of conjoined twins, accurate prenatal diagnosis including definition of the great artery orientation was achieved in 36 of 47 cases (77%). Seven of 17 fetuses with DORV anatomy, of which 6 were thought to have a subpulmonary ventricular septal defect (VSD), had incorrect prenatal assessment of the great artery relationships. One fetus thought to show features of TA had aortic atresia with VSD and normal-sized left ventricle. Of the 42 pregnancies that continued, 15 had major extracardiac malformations and/or chromosomal abnormalities of which one died in utero with trisomy-13 and TA. A further nine died within the neonatal period. Among the 27 fetuses without a documented chromosomal or major extracardiac anomaly, 13 (48%) died. Overall, the survival rate beyond 28 days of life was 52% (22/42). In contrast, 75% (6/8) of fetuses with TOF, excluding the absent pulmonary valve syndrome, survived.

CONCLUSIONS: Conotruncal anomalies can be diagnosed by prenatal echocardiography with a high degree of accuracy. Defining the exact spatial relationship of the great arteries is problematic in some fetuses. The overall prognosis for fetuses with a conotruncal anomaly is poor, with the exception of uncomplicated TOF.