Blood flow velocity changes in the middle cerebral artery as an index of the chronicity of hypertension.

This study was designed to demonstrate cerebral hemodynamic changes related to hypertension using transcranial Doppler ultrasonography. We measured the flow velocities and the Gosling pulsatility index of the middle cerebral artery and the internal carotid artery in 94 stroke-free, hypertensive patients and 81 age- and gender-matched healthy controls. Compared with the control subjects, patients with a longer duration (> or = 5 years) of hypertension showed significantly lower flow velocities of the middle cerebral artery and a higher Gosling pulsatility index of the middle cerebral- and the internal carotid artery. These differences were not observed in patients with a shorter duration of hypertension (<5 years). In the patient group, the mean velocity of the middle cerebral artery was significantly and inversely correlated with the duration of hypertension. Decreased flow velocity with increased pulsatility observed in this study suggest that alterations in the small cerebral vessels and arterioles contribute primarily to cerebral hemodynamic changes occurring in long-standing hypertension and also suggest the possible usefulness of transcranial Doppler in monitoring the progression of cerebral atherogenesis related to hypertension.