Natural history of prenatal ventricular septal defects and their association with foetal echocardiographic features.
Objective: 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.
Methods: 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.
Results: 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.
Conclusions: 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.