Common arterial trunk in the fetus: characteristics, associations, and outcome in a multicentre series of 23 cases.

OBJECTIVE: To assess the accuracy of prenatal diagnosis, the incidence of extracardiac and chromosomal anomalies, and the perinatal outcome in a population of fetuses with common arterial trunk (CAT).

DESIGN: Observational study of 23 fetuses from three referral centres with a confirmed diagnosis of CAT. All underwent fetal echocardiography, detailed anatomical scanning, and karyotyping. In 19 cases, FISH analysis was done to detect 22q11 microdeletion. The following variables were evaluated: gestational age at diagnosis, anatomical variants of the CAT, presence of extracardiac and chromosomal anomalies, pregnancy, and fetal-neonatal outcome. Necropsy reports and postnatal files were available for confirmation of the prenatal diagnosis in all cases.

RESULTS: The prenatal diagnosis proved correct in 23 of 24 cases, the last being pulmonary atresia with ventricular septal defect (PAVSD). A second cardiovascular anomaly was present in eight cases (34.8%); extracardiac anomalies were found in 10 (43.4%). FISH analysis showed 22q11 microdeletion in six of 19 cases (31.6%). Outcomes were as follows: eight terminations of pregnancy (34.8%), two intrauterine deaths (8.7%), five postnatal deaths (before or after surgery) (21.7%); the remaining eight neonates (34.8%) are alive and thriving after surgery (six) or awaiting surgery (two).

CONCLUSIONS: CAT can be reliably diagnosed and characterised in prenatal life, although differentiation from PAVSD may be challenging. The association with chromosomal anomalies is consistent (8.7%), but there is a higher risk of 22q11 microdeletion (31.6%), in agreement with postnatal studies. The relatively poor survival rate (34.8%) reflects the high rate of terminations and the unfavourable cardiac anatomy in some cases.