Fetal Complete Common Atrioventricular Canal Defect: Spontaneous Closure of the Ventricular Septal Defect—In Utero Anatomic Evolution and Postnatal Outcomes

We describe in utero anatomic evolution and postnatal outcome of complete common atrioventricular canal defect (CCAVCD). Retrospective data on 31 fetuses with CCAVCD were analyzed. We reviewed prenatal and postnatal echocardiograms, karyotype, and postnatal outcomes. A total of 20 fetuses had complete data, 18 with serial fetal echocardiograms and postnatal data and 2 terminations. At initial examination, isolated CCAVCD was seen in 12 (67%) fetuses while 6 (33%) were associated with heterotaxy syndrome. On follow-up, 4 fetuses (22%) had spontaneous closure of the inlet ventricular septal defect (VSD) component of the CCAVCD, seen both at 30 to 35 weeks of gestation and on postnatal echocardiograms. These 4 fetuses had previously demonstrated CCAVCD between 18 and 25 weeks of gestation. A total of 15 (83%) patients underwent operative correction, 10 with isolated complete atrioventricular septal defect and 5 with heterotaxy had surgical repair. Four infants in whom spontaneous intrauterine closure of the VSD component was observed had no VSD noted at surgery and underwent closure of primum atrial septal defect and repair of the left atrioventricular (AV) valve cleft. Our data demonstrate that CCAVCD diagnosed during fetal life is not a static anomaly. In our series, an inlet VSD less than 4mm and Rastelli type A anatomy (AV valve attachment to septal crest) during second trimester may evolve during third trimester by formation of AV sulcus pouch and spontaneous closure of the VSD. To the best of our knowledge, this is the first study to report such anatomic evolution of CCAVCD in the fetus. This information is vital for appropriate counseling for expectant parents.