Mitral valve replacement for idiopathic hypertrophic subaortic stenosis. Results in 27 patients.

Treatment of idiopathic hypertrophic subaortic stenosis (IHSS) remains a controversial problem and depending upon many factors, medical or surgical treatment may be elected. When medical therapy fails and surgery is recommended, choice of an appropriate surgical technique may be difficult. An analysis is given of 27 patients who have undergone only mitral valve replacement as definitive treatment. Twenty-six patients were dismissed from the hospital with good or excellent results and one died (3.7 percent mortality). Pressure gradients across the left ventricular outflow tract after operation were eliminated in every instance. The mean preoperative gradient was 74 mm Hg and postoperatively was 6.9 mm Hg. Advantages and disadvantages of mitral valve replacement as definitive treatment of IHSS are presented. This method of treatment should be reserved for patients with incapacitating symptoms, congestive heart failure, severe left ventricular hypertension, unusual electrocardiographic findings or in patients who have failed to respond favorably to previous septectomy.