Subaortic Stenosis

Clinico-Anatomic Study and Results of Surgery in 17 Cases

¹ Department of Surgery, University of Minnesota Medical Center and Variety Club, Heart Hospital

Seventeen cases of subaortic stenosis operated between 1956-64 had been reviewed. Their age ranged between four and 41 years. Ten were females and seven males.

Sixteen patients presented congenital lesions and one acquired. Discrete, fibrous ring type obstruction was found in nine, diffuse muscular hypertrophy in six, accessory mitral valvular tissue was encountered in one and calcific subaortic stenosis in one. Associated valvular disease was frequently present. The most common was mitral insufficiency in five patients, with aortic valvular stenosis being present in four.

The clinical, radiographic, and electrocardiographic features of subaortic obstruction have been briefly reviewed.

Each of the patients was operated utilizing cardiopulmonary bypass. The subaortic stenosis was approached by the left ventricle in two and though the left atrium in three. As a result of this experience, the trans-atrial approach is recommended as the one choice for the diffuse muscular type of subaotic obstruction and the transaortic for the discrete fibrous type when located high in the ventricular outflow track.

Two operative and two late deaths at home constituted the mortality. Thirteen patients are alive and have been followed for from one month to six years after surgery. Eleven patients are well. One patient continues to have symptoms and a significant gradient following surgery and one patient developed a ventricular aneurysm at the site left ventriculotomy. As a result of operation, the systolic gradient across the subaortic area has been significantly reduced in the majority of patients and abolished completely in four.