Common carotid blood flow in patients with hypertension and stenosis of the internal carotid artery.

Common carotid blood flow has been measured using pulsed Doppler techniques in hypertensive patients over 45 years of age, with and without stenosis of the internal carotid artery. In hypertensive patients without stenosis, arterial diameter remained within the normal range, whereas blood flow velocity and blood flow were significantly reduced. Vascular resistance was significantly increased but did not change markedly after administration of the vasodilating drug isosorbid dinitrate. Patients with hypertension and stenosis of the internal carotid artery were compared with two different populations used as controls: In comparison with hypertensive patients without stenosis of the internal carotid artery, both arterial diameter and blood flow velocity were reduced, leading to a more pronounced decrease in blood flow; and in comparison with normotensive patients with stenosis of the internal carotid artery, common carotid blood flow was more reduced at any degree of stenosis. In a subset of patients, blood flow returned toward normal ranges after endarterectomy. The study suggested that in patients with hypertension without stenosis of the internal carotid artery, the decrease in blood flow is due to a decrease in blood flow velocity with normal arterial diameter despite the elevated blood pressure, and in patients with hypertension and stenosis of the internal carotid artery, blood flow was more reduced than in the normotensive patients with stenosis of the internal carotid artery, suggesting that caution must be taken with indications of antihypertensive treatment.