Which of the following statements about subvalvular aortic stenosis are true?

C. The subaortic membrane is approached surgically via the aorta and aortic valve.

D. A concomitant septal myectomy decreases the incidence of recurrent subaortic stenosis.

DISCUSSION: Subaortic stenosis is rarely encountered in neonates. Most often it is discovered in an asymptomatic child during a routine physical examination. A loud crescendo–decrescendo systolic murmur without an ejection click is usually noted. The presence of an ejection click is more consistent with isolated valvular aortic stenosis. Discrete subaortic stenosis is approached surgically with cardiopulmonary bypass, aortic cross-clamping, and cardioplegic arrest. The aorta is opened and the aortic valve leaflets are retracted, exposing the fibrous membrane. The fibrous ring is carefully excised, taking care to avoid injury to the anterior leaflet of the mitral valve and the penetrating conduction bundle. Once the subaortic membrane is excised a septal myectomy further opens the left ventricular outflow tract and diminishes the likelihood of recurrent subaortic stenosis.