Long-Term Pediatric Outcome of Isolated Discrete Subaortic Stenosis

Background: The management of pediatric discrete subaortic stenosis remains controversial. Objectives: Document the natural history and surgical outcomes for discrete subaortic stenosis to adolescence. Methods: Retrospective review of clinical and echocardiographic findings in 74 patients diagnosed in childhood between 1985 and 1998. Results: Twenty-five patients were followed only medically for 9.4 +/- 0.9 years to 15.9 +/- 0.6 years of age. Their echocardiographic left ventricular outflow peak gradient did not progress, 19 +/- 1.4 (SEM) vs 20 +/- 2.3 mm Hg. The proportion with aortic insufficiency (AI) increased (4% to 52%). Forty-nine patients were operated for discrete subaortic stenosis at 7.8 +/- 0.6 years. Their peak gradient at diagnosis was 36 +/- 3 mm Hg with AI in 33%. Preoperatively their peak gradient progressed to 60 +/- 5 mm Hg with AI in 82%. Assessment 6.2 +/- 0.5 years postoperativly showed a peak gradient of 14 +/- 2 mm Hg with AI in 88%. Ten patients required reoperation for recurrent discrete subaortic stenosis, 3 acquired complete heart block, and 1 developed endocarditis. There was no mortality. At diagnosis, surgical patients were younger, had greater peak gradients, and greater incidence of AI, than those followed only medically. The progression of discrete subaortic stenosis was positively associated with severity of obstruction and negatively associated with older age at diagnosis. The risk of having surgery over time was associated with greater preoperative obstruction and presence of AI. Conclusions: Many pediatric patients with mild discrete subaortic stenosis exhibit little progression of obstruction and need not undergo immediate surgery. Others with more severe stenosis may progress precipitously and will benefit from early resection.