The role of plasma endothelin in the Fontan circulation

BACKGROUND: Various vasoactive substances are released during cardiopulmonary bypass. They may deteriorate pulmonary circulation after the Fontan operation. Effects of plasma endothelin-1 (ET-1), a vasoconstricting peptide, on the Fontan circulation have not been investigated. METHODS: Eleven patients (aged 11.1+/-7.5 years) who underwent the modified Fontan operation (group F) and seven patients (aged 9.9+/-6.0 years) who underwent the biventricular repair (group C) were studied. Plasma samples were obtained for measuring ET-1 on the first postoperative day (Early I), on returning to floor care from the intensive care unit (Early II), and during postoperative cardiac catheterization (Late). RESULTS: Plasma concentrations of ET-1 increased in group F (Early I, 4.37+/-1.78 pg/ml; Early II, 4.07+/-1.90 pg/ml) as compared with the basal value of 1.0+/-0.5 pg/ml. The central venous pressure, which reflects the pulmonary circulatory state, soon after the Fontan operation correlated significantly with the increased ET-1 concentration (y=1.809 x+6.484; r=0.809; p=0.0026). Although the Late ET-1 concentrations in group F were significantly decreased, the central venous pressure and the ET-1 concentrations demonstrated a significant correlation (y=3.074 x +5.427; r=0.740; p=0.0227). CONCLUSIONS: The increased humoral vasoactive substances such as ET-1, which induces pulmonary vasoconstriction following the Fontan operation, may have important implications for the Fontan circulation.