Plasma endothelin-1 in patients with stable or unstable angina

Background: It has been documented that an elevated endothelin-1 (ET-1) plasma concentration is associated with an increased risk of serious coronary events and the presence of angiographically documented coronary artery disease (CAD). The results of a few studies which examined ET-1 plasma level in patients with stable or unstable angina, were inconclusive. Aim: To assess whether ET-1 blood concentration measured in the coronary sinus and peripheral vein is associated with clinical symptoms in patients with multi-vessel CAD. Methods: The study group consisted of 23 patients with multi-vessel CAD of whom 11 had unstable angina and 12 - stable angina. Both groups were matched with regard to age, gender and the presence of cardio-vascular risk factors. Blood samples for ET-1 assessment were taken during coronary angiography simultaneously from the coronary sinus and femoral vein. ET-1 was measured using an immunoenzymatic method. Results: ET-1 plasma level in the peripheral venous circultion was similar in patients with unstable or stable angina (0.45±0.18 pmol/L versus 0.46±0.14 pmol/L, NS) whereas ET-1 level in the coronary sinus was significantly higher in patients with unstable angina (1.44±0.47 pmol/L versus 0.34±0.17 pmol/L, p Conclusions: ET-1 concentration in the coronary sinus is significantly higher in patients with unstable rather than stable angina which confirms the role of ET-1 in the pathogenesis of CAD. Our results suggest a possible future role of endothelin receptor blockers in the treatment of patients with unstable angina.