[Involvement of endothelin and prostanoids in coronary vasospasm]

The involvement of endothelin, an important endogenous vascular constrictor, and prostanoids in coronary vasospasm was evaluated in 14 patients with and 12 patients without coronary vasospasm who had normal coronary angiograms. Coronary vasospasm was defined as a total or subtotal occlusion or diffuse and intense constriction of the left coronary artery provoked by intracoronary acetylcholine administration and associated with electrocardiographic ischemic ST-segment shifts. Blood samples were taken from the left coronary ostium and the coronary sinus before and during coronary spasm. The blood concentrations of endothelin, 6-keto-PGF1 alpha, and thromboxane B2 were measured. Patients with and without coronary vasospasm demonstrated no significant changes in endothelin and thromboxane B2 concentrations in the coronary sinus blood, or in the difference between left coronary ostium and coronary sinus blood. Patients with coronary vasospasm had 6-keto-PGF1 alpha concentrations in the coronary sinus before and during coronary vasospasm of 133.6 +/- 32.5 and 179.4 +/- 46.7 pg/ml, respectively (p < 0.05), and the differences between coronary sinus and coronary ostium concentrations were -25.7 +/- 29.5 and 41.6 +/- 22.6 pg/ml, respectively (p < 0.05). Patients without coronary vasospasm showed no significant changes in 6-keto-PGF1 alpha concentration. Endothelin and thromboxane A2 are not involved in coronary vasospasm, while prostacyclin concentration rises during coronary vasospasm provoked by acetylcholine.