In the past, cases of pulmonary stenosis have been surgically corrected by variations of the Brock1 procedure, with instrumentation through the right ventricle to open the stenosed pulmonary valve. Swan2 has demonstrated by postoperative cardiac catheterization studies that a valvulotomy so performed may be inadequate and responsible for failure of reduction of right ventricular pressure as compared to those performed by the open method through the pulmonary artery with the patient under hypothermia.
We have attempted to ensure an adequate valvulotomy by the use of direct-pressure measurements taken in the right ventricle and pulmonary artery at the operating table both before and after the valvulotomy in order to evaluate the effectiveness of the technical maneuver and adequacy of the opening.3 If sufficient equalization of the two pressures on opposite sides of the pulmonary valve failed to occur, further attempts were made to open the pulmonary valve until
Kay EB, Zimmerman HA, Cross FS. DIRECT-VISION INTRACARDIAC SURGERY FOR PULMONARY STENOSIS. JAMA. 1956;162(6):563-564. doi:10.1001/jama.1956.72970230005009b