Discrete Subaortic Stenosis: Long-Term Prognosis on the Progression of the Obstruction and of the Aortic Insufficiency

Abstract

We sought to determine the long-term rate of progression of left ventricular outflow tract (LVOT) obstruction and aortic insufficiency (AI) in adult patients operated on for discrete subaortic stenosis (DSS). Between 1975 and 1995, 52 patients underwent surgery for DSS; their mean age was 25.4 +/- 14.8 years. Mean preoperative LVOT gradient was 72.8 +/- 25.7 mm Hg. Excision of the subaortic membrane was carried out in all patients, myectomy of the interventricular septum was additionally carried out in 8 patients (15.4 %), and aortic valve replacement (AVR) was performed in 15 patients (28.8 %). There were 2 operative deaths (3.8 %). Early postoperative LVOT gradient was 9.7 +/- 6.5 mm Hg. Follow-up ranged from 8.1 to 26.6 years. There were 8 late deaths (16.3 %), and mean LVOT gradient was 13.3 +/- 10.7 mm Hg. Five patients required reoperation for recurrent obstruction; 4 patients had a gradient of more than 30 mm Hg. The AI, in patients who did not undergo aortic valve replacement, did not substantially change during follow-up. DSS is a variable, unpredictable and progressive disease; recurrent obstruction may reappear despite the adequacy of surgical excision, and is not related to preoperative gradient. Mild AI remains substantially unchanged and AVR is indicated in severe AI.