Right ventricular outflow obstruction with intact ventricular septum in adults.

Cardiothoracic surgeons whose practice is limited to adults rarely see patients with right ventricular outflow obstruction and an intact ventricular septum. Of more than 10,000 open-heart procedures performed at our institution from 1983 to 1993 (in patients 18 to 75 years old), only 5 procedures were for correction of this problem. Both the pulmonary valve and the subvalvular area were abnormal in these 5 patients, and 4 of the 5 had subvalvular stenosis. The gradient across the right ventricular outflow tract was measured by cardiac catheterization before repair in all patients and averaged 118 mmHg. Various surgical approaches were used for repair. In the 2 patients whose pressures were measured postoperatively, the gradients were 25 mmHg and 45 mmHg, respectively. There were no operative deaths. At follow-up (range, 2 months to 5 years after surgery), all patients were in New York Heart Association functional class I and all had murmurs. Those who underwent echocardiography were found to have minimal gradients across the right ventricular outflow tract.