Progressive discrete subaortic stenosis developed after successful primary repair of the supravalvular aortic stenosis in Williams syndrome.

Discrete subaortic stenosis is a rare, late complication of the surgical repair of congenital heart defects. Secondary subaortic stenosis late after surgical repair of supravalvular aortic stenosis in Williams syndrome has not previously been described. A 20 year-old female patient with Williams syndrome became symptomatic eight years after subaortic membrane resection. A discrete subaortic stenosis was identified by echocardiography. She was indicated for a Konno operation with a 19-mm Sorin SL valve inserted in the aortic position, along with ventricular septal defect closure with a pericardial patch. She produced a transient slight hypocalcemia after the operation. She was discharged home in a good condition on the fourth post-operative day. Intracardiac morphological and hemodynamic factors have been suggested as responsible for such a late complication. Our case study suggests the need for regular follow-up in patients with Williams syndrome, even after primary surgical repair.