Cerebral hemodynamics in hypertensive patients compared with normotensive volunteers. A transcranial Doppler study.

BACKGROUND AND PURPOSE

The present study was designed to examine cerebral hemodynamics in early and chronic stages of hypertension using transcranial Doppler sonography.

METHODS

Our study population consisted of 16 chronic hypertensive patients with chronic and small deep brain infarction, 10 young early-stage hypertensive subjects, and 16 young normotensive healthy volunteers. Using three-dimensional mapping techniques, we identified the M1 portion of the middle cerebral arteries and measured mean blood flow velocity, and we calculated the Gosling pulsatility index (PI), Fourier PI of the first harmonic (Fourier PI1), and cerebrovascular resistance.

RESULTS

Mean blood flow velocity in the young hypertensive group was statistically higher (71.7 +/- 11.7 cm/s [mean +/- SD]) than among chronic hypertensive subjects (56.9 +/- 21.4 cm/s, P < .01) and normotensive subjects (63.2 +/- 11.8 cm/s, P < .05). Gosling PI presented a mirror image of mean blood flow velocity in both hypertensive and normotensive subjects. Chronic hypertensive subjects showed significantly higher Fourier PI1 (0.32 +/- 0.05) and cerebrovascular resistance (2.08 +/- 0.82 mm Hg/cm per second) than normotensive subjects (0.25 +/- 0.03 and 1.31 +/- 0.23 mm Hg/cm per second [P < .005], respectively) or early-stage hypertensive subjects (0.25 +/- 0.04 and 1.44 +/- 0.26 mm Hg/cm per second [P < .02], respectively).

CONCLUSIONS

Early-stage hypertensive subjects demonstrated higher velocity, normal Fourier PI1, and near normal vascular resistance, whereas chronic hypertensive subjects showed near normal velocity, higher Fourier PI, and greater vascular resistance. Results may indicate different degrees of cerebral arteriopathy and arteriolopathy between early and late stages of hypertension.