Aortic regurgitation after surgical relief of subvalvular membranous stenosis. A long-term follow-up study.

A postoperative follow-up study of 21 cases of discrete membranous subvalvular aortic stenosis is presented. The age at operation was 6-47 (mean 16) years, and the follow-up time 0.6-16 (mean 6.7) years. Preoperatively most patients were in NYHA function class II or III and had high peak systolic pressure gradient, left ventricular hypertrophy and/or cardiothoracic index greater than 0.50. At follow-up all but six patients were in NYHA class I, the Doppler-estimated peak systolic gradient was 0-36 (mean 18) mmHg, the cardiothoracic index unchanged and the mean left ventricular hypertrophy score had declined from 4.3 to 2.3. Of 13 patients without aortic regurgitation preoperatively, eight had regurgitation at follow-up (group I) and five did not (group II). The interval to follow-up was significantly longer and the preoperative peak systolic gradient was greater in group I than in group II. Aortic regurgitation may develop even after surgical relief of discrete membranous subvalvular aortic stenosis, possibly associated with high preoperative pressure gradient and time from operation. Regular postoperative Doppler echocardiography is therefore recommended.