Subvalvular Aortic Stenosis.

Subvalvular aortic stenosis (SAS) is a congenital heart defect that causes fixed form of hemodynamically significant left ventricular outflow tract (LVOT) obstruction with progressive course. It has a spectrum of anatomy. It appears usually beyond infancy, causes left ventricular hypertrophy and myocardial dysfunction, and tends to involve the aortic and mitral valves in its progressive course. Although most of the patients are asymptomatic, careful monitoring is essential. Moderate to severe SAS requires surgical resection and septal myomectomy. There is a high rate of postoperative recurrence of the lesion. Recurrent lesions and the complex type of lesions with aortic valve involvement should have aortoseptoplasty (to enlarge the outflow tract) and Ross procedure (removal of the damaged aortic valve and placement of a pulmonary autograft in the aortic position and a pulmonary homograft in the pulmonary position).