Left ventricular outflow tract obstruction in children.

ABSTRACT

Left ventricular outflow tract obstruction is classified by site of presentation into valvular, subvalvular, and supravalvular forms. This disorder affects multiple age groups, and success rates of operative therapies vary dramatically. Abnormalities in any of the three principal anatomic sites of the LV outflow tract can lead to obstruction. Valvular stenosis is the most common, and when present in infants, carries a high mortality rate. Subvalvular stenosis is much less common and may present as a discrete ring or a diffuse tunnel. Supravalvular stenosis is the least common and likewise has discrete and diffuse forms. These various forms of obstruction require surgical relief. Each operation must be tailored to the individual patient and may comprise simple valvotomy for bicuspid aortic valve or complex intraventricular manipulations to ameliorate diffuse subaortic tunnel. The mortality for valvotomy alone can range from 0 to 70%, depending on the age of the patient at the time of surgery. Additionally, the possibility for recurrent stenoses after operation is always present. For these reasons, therapy and interventions directed toward relief of LVOTO must be considered palliative, and lifelong patient follow-up is necessary.