[Subaortic stenosis associated with perimembranous ventricular septal defect. Clinical follow-up of 36 patients].

Objective: To study the clinical pattern of subaortic stenosis associated with perimembranous ventricular septal defect.

Methods: From January 1979 to June 2000, 36 children with perimembranous ventricular septal defect and fixed subaortic stenosis were followed-up regarding anatomic characteristics, evolvement, and clinical events.

Results: Age at diagnosis of subaortic stenosis ranged from 6 months to 170 months, and it was less than 1 year in only 2 children. Regarding sex, the distribution was 2:1 with a greater predominance of males. Ventricular septal defect was small in 61.0% of cases, medium in 30.56%, and large in 8.40%; the size of the septal defect decreased during follow-up in 30.56% (11 cases). In all patients, subaortic stenosis was membranous and fixed. During follow-up, 23 patients experienced evolvement of the stenosis. Surgical treatment was performed in 21 cases, and one patient underwent surgery for restenosis. Infectious endocarditis occurred in 2 patients; one of the patients died.

Conclusion: Subaortic stenosis occurs in the natural history of ventricular septal defect usually after the first year of life, and it is progressive and requires surgery in most cases.