Effect of Angiotensin Converting Enzyme Inhibitor (Captopril) on Cerebral Blood Flow in Hypertensive Patients without a History of Stroke

Abstract

The effect of the angiotensin converting enzyme inhibitor, captopril, on cerebral blood flow (CBF) was studied in 11 hypertensives without a history of stroke. Mean hemispheric CBF (mCBF) was measured in each patient by Xe-133 inhalation method before and after 7 days of captopril administration. Blood pressure (BP) both in the control state and at the time of CBF measurement decreased significantly after drug administration. mCBF, however, did not show any significant change. When percent changes in mCBF before and after the administration were plotted against those of mean arterial BP, significant inverse correlations were obtained in both hemispheres; the larger the BP decrease, the more increase in CBF was observed.

It is concluded that captopril lowers systemic BP without concomitant decrease in CBF in hypertensive subjects with no history of stroke. Furthermore, the results suggest that captopril may have a vasodilating action on cerebral blood vessels.

Key Words:

• Autoregulation
• captopril
• cerebral blood flow
• converting enzyme inhibitor
• hypertension
• Xe-133 inhalation