Natural history and surgical outcomes for isolated discrete subaortic stenosis in children

Objective-To document the natural history and surgical outcomes for discret e subaortic stenosis in children. Design-Retrospective review. Setting-Tertiary care paediatric cardiology centres. Patients-92 children diagnosed between 1985 and 1998. Main outcome measures-Echocardiographic left ventricular outflow gradient ( echograd), and aortic insufficiency (AI). Results-The mean (SEM) age at diagnosis was 5.3 (0.4) years; the mean echog rad was 30 (2) mm Hg, with Al in 22% (19/87) of patients. The echograd and incidence of AI increased to 35 (3) nun Hg and 53% (36/68) (p < 0.05) 3.6 ( 0.3) years later. The echograd at diagnosis predicted echograd progression and appearance of AI. 42 patients underwent surgery 2.2 (0.4) years after d iagnosis. Preoperatively echograd and AT incidence increased to 58 (6) nun Hg and 76% (19/25) (p < 0.05). The echograd was 26 (4) nun Hg 3.7 (0.4) yea rs postoperatively, with Al in 82% (31/38) of patients. Surgical morbiditie s included complete heart block, need for prosthetic valves, and iatrogenic ventricular septal defects. Eight patients underwent reoperation for recur rent subaortic stenosis. The age at diagnosis of 44 patients followed medic ally and 42 patients operated on did not differ (5.5 (0.6) v 5.0 (0.6) year s, p < 0.05). However, the echograd at diagnosis in the former was less (21 (2) v 40 (5) nun Hg, p < 0.05) and did not increase (23 (2) mm Hg) despite longer follow up (4.1 (0.4) v 2.2 (0.4) years, p < 0.05). The incidence of AI at diagnosis and at last medical follow up was also less (14% (6/44) v 34% (13/38); 40% (17/43) v 76% (19/25), p < 0.05). Conclusions-Many children with mild subaortic stenosis exhibit little progr ession of obstruction or AI and need not undergo immediate surgery. Others with more severe subaortic stenosis may progress precipitously and will ben efit from early resection despite risks of surgical morbidity and recurrenc e.