Background: The number of studies of long-term follow up to adolescence is very low on spontaneous closure (SC) of perimembranous ventricular septal defects (P-VSD) in children not undergoing surgical closure because of small left-to-right shunting.
Methods: Seventy patients with a P-VSD with pulmonary-to-systemic flow ratio (Qp/Qs) < 1.7 underwent cardiac catheterization at the age of 2-10 years (mean, 5.1 years). Excluding 22 patients who dropped out by 15 years, 48 were selected. Qp/Qs ranged from 1.00 to 1.68 (mean, 1.17). The average follow-up period of 37 patients excluding the SC patients was 17.8 years. They were classified according to Qp/Qs into three groups: group I, 1.4 <or= Qp/Qs < 1.7; group II, 1.2 <or= Qp/Qs < 1.4; and group III, 1.0 <or= Qp/Qs < 1.2.
Results: SC occurred in 11 patients (23%). SC rates in group I and II were lower than those in group III (I, 0/8 0%; II, 1/10 10%; III, 10/30 33%). In 23 patients (48%), an aneurysm of the ventricular membranous septum (AVMS) was detected, but no significant relationship was found between the presence of AVMS and SC rate.
Conclusions: SC occurred in 23% of patients with a P-VSD of Qp/Qs < 1.7 up to adolescence. But a P-VSD of Qp/Qs >or= 1.2 showed no tendency to close spontaneously. The factor most influencing SC of P-VSD after school age seemed to be the shunt ratio.