Fixed subaortic stenosis. Natural history of patients with mild obstruction and follow-up of operated patients.

Abstract

Fifty-five patients, 37 men and 18 women, aged 8 to 71 years (median 23) with a diagnosis of fixed subaortic stenosis were seen in our institution between January 1966 and December 1983. Their subvalvular gradient varied between 0 and 135 mmHg. Aortic regurgitation was present in 44 patients. Thirty-eight patients were operated on. Sixteen patients had some additional cardiac disease, either congenital, or acquired. There were 2 early and 2 late deaths. Fifteen patients were studied again after surgery: the average peak-to-peak gradient has decreased from 88 +/- 28 to 19 +/- 16 mmHg and is zero in 5. No patient has needed a reoperation, so far. Of the 17 non-operated patients, 13 had a gradient of less than 50 mmHg; they are all in Class I-II after 1-5 years. The gradient has increased to 70 mmHg in 1 of the 4 recatheterised cases. Four patients have died, 2 suddenly, 2 of congestive heart failure. They all had a gradient of 55 mmHg or more. In conclusion, in asymptomatic patients of a somewhat "older" age, with a high prevalence of a discrete form of subaortic stenosis, an operation can be deferred if the pressure gradient is less than 50 mmHg, and there are no associated lesions. Identification of patients running the risk of sudden death remains elusive.