[Nitrate derivatives and coronary vasomotricity]

Abstract

The action of nitrate derivatives on the coronary arterioles is weak and very short lasting which avoids the phenomenon of a coronary steal syndrome. Investigations of the epicardial coronary vessels require vasoconstriction stress tests, usually using ergometrine, and vasodilatation tests, mainly using isosorbide dinitrate (ISDN). The combination of the two tests allows evaluation of global coronary vasomotricity which is less than 100% variation of diameter. In coronary spasm, ISDN relieves the stenosis in less than 2 minutes in nearly all cases. An infusion of ISDN also prevents most cases of arterial spasm. In effort angina, it has been possible to demonstrate paradoxal vasoconstriction during exercise due to endothelial dysfunction. The direct action of nitrate derivatives on smooth muscle which is not endothelium dependent, prevents the vasoconstriction and increases oxygen supply during exercise.