Natural history of prenatal ventricular septal defects and their association with foetal echocardiographic features

To describe the evolution of ventricular septal defects in infants from intra-uterine diagnosis to the age of 3 years or until documented echocardiographic closure of the defect, as well as any relationship between closure rate, time and foetal echocardiographic features.

Between January, 2004 and December, 2006, 268 cases of congenital cardiac defect were detected in 14,993 pregnancies referred to our hospital for routine foetal echocardiography; of these cases, 125 had isolated ventricular septal defect. The mothers were scheduled for regular ultrasonography every 2 weeks from diagnosis until the ventricular septal defect closed or 3 years postnatally.

Of the 125 cases of ventricular septal defects, the pregnancy was terminated in 25, four resulted in death, two defects closed spontaneously in utero, 55 closed at a mean age of 13.7 months postnatally, 17 were treated with surgery, nine remained unclosed, and 13 cases were lost to follow-up. Only 7.7% of muscular ventricular septal defects remained patent as compared with 35.7% of perimembranous ventricular septal defects (p is less than 0.01). Muscular ventricular septal defects closed earlier than perimembranous ventricular septal defects. All the ventricular septal defects less than or equal to 3 millimetres closed, whereas only 79.5% of the defects greater than 3 millimetres closed before the age of 3 years; 60.9% of the defects less than or equal to 3 millimetres closed before the age of 1 year as compared with 41.7% of the defects greater than 3 millimetres. The velocity of right-to-left flow was negatively correlated with closure rate but not related to closure period.

Ventricular septal defects can close in utero or during the postnatal period, and both the size and site play a role in the natural history, with small and muscular ventricular septal defects having a high closure rate and early closure.