ABSTRACT
OBJECTIVE: To study the incidence and onset of aortic valve prolapse (AVP) and aortic regurgitation (AR) in the ventricular septal defect (VSD). STUDY DESIGN: A prospective cohort study POPULATION: The less than one-year-old children with diagnosis of isolated VSD were studied from October 2000 to September 2006 at Queen Sirikit National Institute of Child Health. Clinical follow-up and echocardiographic studies were scheduled every 2-3 months in the first year of age and then every 6 months to evaluate the size, location, flow across VSD, aortic valve morphology and aortic regurgitation. RESULTS: Three hundred and twenty-one cases of VSD were followed up. One was excluded due to associated hypoplastic RV An overall of 2,644 echocardiograms were performed. The percentage of perimembranous, subpulmonic, muscular inlet and multiple types were 70.3%, 19.4%, 5.6%, 3.1% and 1.6%, respectively. Size of the VSD was diagnosed to be small, moderate, and large VSD in 62.5%, 15.9% and 21.6% respectively. At the end of the study, the incidence of AVP in subpulmonic VSD was 87.1% compared to 16.4% in perimembranous VSD, with a relative risk of 5.30 and the incidence of AR in subpulmonic VSD was 37.1% compared to 5.3% in perimembranous VSD, with a relative risk of 6.95. From the survival analysis, the patient with subpulmonic VSD developed AVP at 46%, 77%, 90% and 94% compare to 8%, 13%, 20% and 23% of perimembranous VSD at 12, 24, 36 and 48 months of age respectively (p < 0.001). The patient with subpulmonic VSD developed AR at 8%, 17%, 35% and 38% compare to 2%, 4%, 5% and 7% of perimembranous VSD at 12, 24, 36 and 48 months of age respectively (p < 0.001). At the end of the study, ninety-six cases (30%) underwent cardiac operation with the indication of heart failure or the occurrence of AR. Sixty one cases (19.1%), including two cases of subpulmonic type had spontaneous closure of VSD. Seven cases (2.2%) had lost to follow up and five cases (1.6%) died during the follow up period. CONCLUSION: The incidence of AVP and AR are high in subpulmonic VSD being much higher than perimembranous VSD with a relative risk of 5.30 and 6.95 respectively. These complications are significantly from infancy period and are an indication for early cardiac surgery.