Natural Aortic Valve Complications of Ventricular Septal Defect: A Prospective Cohort Study
Thanarat Layangool MD*, Tawatchai Kirawittaya MD*, Chaisit Sangtawesin MD*, Vichow Kojaranjit MD*, Perapat Makarapong MD**, Amornrat Pechdamrongsakul RN*, Yanisa Intasorn RN*, Putra Noisang RN*
Affiliation : * Cardiology Unit, Queen Sirikit National Institute of Child Health, Department of Medical Services, College of Medicine, Rangsit University, Bangkok ** Cardiovascular Unit, Rajavithi Hospital, Bangkok
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.
Keywords : Ventricular septal defect, Aortic valve prolapse, Aortic regurgitation, Subpulmonic, Perimembranous, Natural complications, Relative risk
