Impairment of flow-dependent coronary dilation in hypertensive patients: Demonstration by cold pressor test induced flow velocity increase

In normal coronary arteries, increased flow velocity induces endothelium-dependent dilation, and dilation in response to sympathetic stimulation evoked by the cold pressor test is partly due to increased flow velocity. In arterial hypertension, angiographically normal coronary arteries were constricted by acetylcholine, an endothelium-dependent vasodilator. To assess the epicardial coronary artery response to the increased blood flow velocity induced by the cold pressor test in hypertensive patients with angiographically normal coronary arteries, coronary artery diameters and flow velocity were measured during cold pressor test in 12 untreated hypertensive patients and in 10 control subjects. Diameters were determined by quantitative angiography on proximal and distal segments of the left anterior descending coronary artery, and flow velocity measurements were made by Doppler testing in the distal segment. In control subjects, the proximal and distal segments dilated dur ing cold pressor test by 12.0 ± 4.5% and 13.9 ± 6.5%, respectively (both P P P P P