Natural History in Isolated Ventricular Septal Defect

Three-hundred-fifty-five children with isolated ventricular septal defect (VSD) from the Cerrahpaşa Pediatric Clinic were followed up for 1701 patient years in order to determine the natural course of specific hemodynamic classes. The results were compared with 288 patients who could not be followed up. The natural course was represented well, because the patient material disclosed a wide spectrum of the disease, and also losses due to operation (2.8 %) or to mortality (1.7 %) were very low. According to the distribution of the hemodynamic classes in relation to age, the high rate of pulmonary hypertension (PH) (75-80 %) observed under 6 months of age decreased to 5 %, and the rate of those with small defects increased from 5 % to 67 % with the increase of age. There was a decrease of left to right shunt and an increase of spontaneous closure with incerasing age. PH patients were divided into two left to right shunt groups: (a) those with mild and (b) those with moderate to severe shunts. In both groups while the rate of PH decreased, the rate of those with either small shunts or with spontaneous closure increased with age. In the group with mild shunt (II a), the persistence of PH decreased to 0 % in those who could be followed up more than 5 years. The mild degree of left to righ shunt persisted in the majorirty of patients (64 %), and the rate of spontaneous closure was 33 %. In group II b, however, the rate of persistence of PH was 9 %, abundant left to right shunt continued in anather 20 %. The shunt decreased significantly in 70 %: II b's were transformed to I a in 51 %, and defects closed spontaneously in 18 %. In the group of 81 patients with abundant shunt but no PH (I b), 63 were followed up since age ? 2 years, and 48 since age ? 1 year. The following results were obtained: 1) PH did not develop in any of them; 2) The incidence of those remaining in the same group varied between 12 to 20% according to the follow-up period. The shunt decreased significantly in 65 %, and sontaneous closure of the defects was observed in 20 %. In the group with small left to right shunt and no PH (I a): 1) defect closed spontaneously in the majority (50-62.5 %); 2) the VSD persisted with a small shunt in 30-35 %; none developed PH.