Physiologic role of coronary PGI2 and PGE2 in modulating coronary vascular response to sympathetic stimulation.

To investigate a physiologic role of coronary prostacyclin (PGI2) and prostaglandin E2 (PGE2) 30 patients who were not affected by coronary heart disease were evaluated for coronary hemodynamics and coronary PGI2 and PGE2 production. Inhibition of coronary prostaglandin biosynthesis by ketoprofen (1 mg/kg) or aspirin (15 mg/kg) administered intravenously did not significantly change coronary hemodynamics in resting conditions. In all patients cold pressor tests induced significant increases in coronary blood flow (p less than 0.001) and decreases in coronary vascular resistance (p less than 0.001) without changes in cardiac oxygen extraction and with consequent increases in calculated myocardial oxygen consumption. Simultaneously, a marked increase in coronary PGI2 (as 6-keto-PGF1 alpha) and PGE2 formation was observed (p less than 0.001). Both ketoprofen (1 mg/kg) and aspirin (15 mg/kg) administration completely abolished PGI2 and PGE2 formation that was induced by cold pressor test and caused a paradoxical increase in coronary vascular resistance (ketoprofen: p less than 0.02; aspirin: p less than 0.05). The results of this study support a physiologic role for the coronary prostaglandins in modulating coronary vascular response to sympathetic stimulation in nonischemic patients.