Right ventricular outflow tract prosthesis in total correction of tetralogy of Fallot

Abstract

Right ventricular outflow tract obstruction was relieved by placing outflow patches across the pulmonary annulus in 39 of 195 patients who underwent total correction of tetralogy of Fallot. The mortality rate in these 39 patients was 12.8%, which did not differ significantly from the overall mortality of 11.3% (p=1.00). The ratio of the pulse pressure to pulmonary artery systolic pressure as an index of pulmonary insufficiency was dependent on the cross-sectional area index (CSAI) of the pulmonary annulus after enlargement, as shown in the regression equation Y=1-0.63/(X-0.07) (r=0.79, p<0.05). When the CSAI was 2.5 cm2/m2 or less and a single cusp was mounted on the outflow patch, the pulmonary insufficiency was negligible and the right ventricular end-diastolic pressure was 10 mm Hg or less. In patients without outflow patches, the right ventricular-to-pulmonary arterial systolic pressure gradient and the right ventricular-to-aortic systolic pressure ratio 1 month after surgery was dependent on the CSAI, as shown in the regression equations Y=54.0/X2 + 5.6 (r=0.76, p<0.01) and Y=0.42/X2 + 0.36 (r=0.72, p<0.01), respectively. These two equations may also be applied in the case of patients with outflow patches with a single cusp. Thus, when the outflow patch is used, the CSAI must be larger than 1.75 cm2/m2 and less than 2.5 cm2/m2, and a single cusp should be mounted on the outflow patch.