Increased circulating endothelins are not of cardiopulmonary origin in heart failure patients.

Objective: Plasma concentrations of endothelin-1 and big-endothelin are increased in heart failure patients. However, the precise contribution of endothelin secretion from the cardiopulmonary system remains unresolved. The aim of this study was to investigate whether the cardiopulmonary system contributes to the circulating endothelin-1 and big-endothelin concentrations in heart failure patients.

Material And Methods: Blood samples were obtained at right heart catheterization from different cardiovascular regions including the coronary sinus in chronic heart failure patients (n=12) and from age-matched control subjects (n=12).

Results: The peripheral plasma concentrations of endothelin-1 were almost 3-fold higher in heart failure patients compared with the control subjects (1.25 pmol/l, 0.30-8.20 pmol/l (median, range) versus 0.46 pmol/l, 0.10-0.88 pmol/l, p<0.01). However, the endothelin-1 concentration was approximately 25% lower in plasma samples from the coronary sinus than in plasma from the inferior caval vein (p<0.05) in the heart failure patients. There were no differences in big-endothelin concentrations between any of the cardiovascular regions.

Conclusions: In heart failure patients, increased plasma concentrations of endothelin-1 and big-endothelin mainly reflect an increased secretion from the peripheral endothelium.