Effects of an angiotensin-converting enzyme inhibitor, lisinopril, on cerebral blood flow autoregulation in healthy volunteers.

The effects of a single oral dose (20 mg) of lisinopril on systemic, carotid (pulsed Doppler), and cerebral (middle cerebral artery, transcranial Doppler) hemodynamics have been investigated over an 8-h period in eight healthy volunteers in a double-blind placebo-controlled crossover study. In addition, cerebral vasodilatory reserve was measured (acetazolamide test). Lisinopril did not affect systemic hemodynamics but it increased both common carotid artery blood flow (+26.2%, p < 0.01) and diameter (+4.5%, p < 0.05) after 8 h. Lisinopril did not affect middle cerebral artery mean blood flow velocity but increased cerebral resistance index (+8.1%, p < 0.05) at 4 h and cerebral vasodilatory reserve (+24.8%, p < 0.05). These data suggest that lisinopril produces a paradoxical vasoconstriction of the small cerebral arterioles. This vasoconstriction might be a compensatory mechanism to a dilation of large cerebral arteries, thus resulting in an unchanged cerebral blood flow.

RCT Entities:   Population Interventions Outcomes