Pulmonary stenosis with intact ventricular septum: assessment and indication of reconstructive surgery for residual right-ventricular outflow tract obstruction.

If not all of the right ventricular outflow tract obstruction (RVOTO) is removed in the operation for pulmonary stenosis, high right ventricular pressure can sometimes occur afterward. However, it is not easy to assess the amount of RVOTO that is to be removed, and there is no quantifiable method for selecting operative procedures. The aim of this report is to discuss the formulation of a numerical indicator, based on the parameters peak systolic right-ventricular pressure (RVP), systolic systemic arterial pressure (AP), pulmonary valvular orifice size (VS), and body surface area (BSA), from the results obtained in sixty-four open heart surgeries for pulmonary stenosis with intact ventricular septum. A group, in which an outflow tract patch was not used and which had a higher pre-operative RVP/AP ratio, had a tendency to have a correspondingly higher RVP/AP ratio one month after the operation. Most patients with a high RVP/AP ratio one month after the operation showed a significant decrease in this ratio a long time after the operation. But, there were exceptions to this rule where the ratio remained high. Reconstruction of the right ventricular outflow was considered for some patients whose RVP/AP ratios remained high. Reconstruction of the RVOT by using an outflow tract patch worked well for patients with an associated infundibular stenosis. A subannular patch was used for patients with infundibular stenosis, and a transannular patch was used for patients with annular stenosis. The optimal annulus size was such that VS/BSA was not less than 2 cm2/m2. A transannular monocusp patch was applied to an area which was more than 10 mm wide.(ABSTRACT TRUNCATED AT 250 WORDS)