Partial atrioventricular septal defect in the fetus: Diagnostic features and associations in a multicenter series of 30 cases

Objective: To assess the anatomical features and the associations of partial atrioventricular septal defect (pAVSD) in the fetus. Methods: This was a retrospective multicenter study of 30 cases of confirmed pAVSD seen since 1996 at two referral centers. The following variables were available for analysis in all cases: indications for fetal echocardiography, diagnostic features, associated cardiac, extracardiac and chromosomal anomalies and fetoneonatal outcome. At fetal echocardiography, the echocardiographic features deemed indicative of pAVSD were: 1) ostium primum atrial septal defect and 2) loss of the normal offset appearance of the atrioventricular valves. Results: Eighteen of the 30 (60%) cases were diagnosed before 24 weeks of gestation and 12 were diagnosed later. Suspicion of congenital heart disease and known aneuploidy (trisomy 21) accounted for 60% of the referral indications. The two anatomical landmarks deemed indicative of pAVSD were detected in all cases at echocardiography. Twelve cases were isolated (one with increased nuchal transluceny at the 12-week scan, one with polyhydramnios, one with fetal growth restriction) including four that were detected on routine ultrasound examination by the authors. Additional cardiac anomalies were present in five (17%) cases, four of which involved aortic coarctation. There were associated chromosomal anomalies in 13 (43%); however, excluding the six cases referred because of known Down syndrome, the adjusted association rate with aneuploidy was 29.2% (7/24). Extracardiac anomalies, including non-chromosomal syndromes, were present in 10 cases (33.3%). Regarding fetoneonatal outcome, there were 13 terminations of pregnancy, one early neonatal death and 16 survivors, including four with mild to severe neurodevelopmental delay due to associated syndromic conditions. Conclusions: We describe the key echocardiographic features of pAVSD in the fetus. In addition, we have confirmed that the association with trisomy 21 holds also for pAVSD, though to a lesser extent, with a 12.5% association rate in this series. In the fetus, pAVSD seems to be associated with a high rate of chromosomal/nonchromosomal syndromic conditions, including skeletal dysplasias. In utero, aortic coarctation represents themost frequently associated cardiac lesion (13.3%).