Circulating endothelin in patients undergoing coronary artery bypass grafting

Increased synthesis of endothelin, (a powerful physiologicalvasoconstrictor), is a uniform response to endothelial injury and has beenassociated with myocardial ischemia and reperfusion. This study tests thehypothesis that coronary artery bypass grafting (CABG) affects endothelinplasma concentrations in various vascular beds. Twenty-four CABG patientswere included in this study. Endothelin was determined in multiple plasmaspecimens obtained from superior vena cava, aortic root and coronary sinus(CS). Venous endothelin plasma concentrations collected in CABG patientsbefore surgery were 1.16 +/- 0.18 pg/ml. They increased after sternotomy(1.71 +/- 0.12 pg/ml) and during (2.97 +/- 0.27 pg/ml) and aftercardiopulmonary bypass (CPB, 2.72 +/- 0.21 pg/ml). There is no net releaseof endothelin from the coronary circulation before (aorta 2.26 +/- 0.13pg/ml vs CS 2.44 +/- 0.17 pg/ml, not significant (n.s.), during(cardioplegia 2.55 +/- 0.17 pg/ml vs CS 2.45 +/- 0.15 pg/ml, n.s.), andafter aortic cross-clamping (aorta 2.95 +/- 0.23 pg/ml vs coronary sinus2.71 +/- 0.18 pg/ml, n.s.). Pulmonary endothelin clearance is preserved onpartial bypass (aorta 2.26 +/- 0.13 pg/ml vs vena cava 2.86 +/- 0.18 pg/ml,P < 0.003), but remains inhibited even 10-30 min after release of theaortic cross-clamp (aorta 2.95 +/- 0.23 pg/ml vs vena cava 2.97 +/- 0.27pg/ml, n.s.). Two out of 24 patients had severe myocardial ischemia. Thesepatients showed particularly high endothelin concentrations.(ABSTRACTTRUNCATED AT 250 WORDS)