REFLEX INCREASE IN CORONARY VASCULAR-RESISTANCE IN PATIENTS WITH ISCHEMIC HEART-DISEASE

To assess possible coronary vasoconstriction in patients with ischemic heart disease, coronary vascular resistance was measured in 12 patients with normal hearts and in 12 with coronary disease before and during the initial 50 s of cold pressor test, a stimulus known to produce systemic vasoconstriction. Control coronary vascular resistance was similar in the 2 groups, and although it did not change in patients with normal vessels, it rose by 27% (P < 0.005) in the group with coronary disease during the cold pressor test. In 3 of 12 patients with coronary disease, coronary flow declined despite an increase in arterial pressure; in 4, angina was precipitated. Phentolamine abolished increases in arterial pressure and coronary vascular resistance during the test in 3 patients with coronary disease. Adrenergically mediated coronary vascular tone may be an important determinant of coronary blood flow and may contribute to ischemia in patients with coronary disease.