Fate of polytetrafluoroethylene monocusp pulmonary valves in an animal model.

Creation of a competent pulmonary monocusp valve facilitates transition from pressure to volume overload following right ventricular outflow tract reconstruction. To determine intermediate-term results and performance of the different types of polytetrafluoroethylene membrane used to construct monocusp valves and transannular patches, 12 infant lambs underwent excision of the native pulmonary valve and insertion of a monocusp valve and transannular patch made from one of 4 types of membrane. Echocardiography was performed after 3, 6, 9, and 12 months, and cardiac catheterization was carried out prior to animal sacrifice at 6 (n = 4) or 12 (n = 8) months. There was no postoperative morbidity or mortality. On echocardiography, 6 valves were mobile (50%), 4 had diminished mobility (33%), and 2 were fixed (17%) prior to sacrifice. At catheterization, mild, moderate, and severe pulmonary regurgitation was observed in 4 valves each (33%), with no stenosis. Right ventricular outflow tract reconstruction with polytetrafluoroethylene monocusp valves can be safely accomplished with good early competence, variable degrees of late insufficiency, and no stenosis. Compared to an open microstructure, the closed polytetrafluoroethylene microstructure showed a milder fibroinflammatory reaction and fewer foci of microcalcification, with sparing of the free edge of the monocusp; this correlated with better intermediate-term hemodynamic performance.