Assessing the effects of antihypertensive medication on cerebral blood flow: demonstration in internal carotid artery occlusion.
Dynamic cerebral blood flow (CBF) studies using acetazolamide or hypercapnia as a vasodilatory challenge have attempted to evaluate intracranial hemodynamics. We report two patients with asymptomatic internal carotid artery occlusion in whom the vasodilatory stimulus was a single oral dose of antihypertensive medication (prazosin hydrochloride or enalapril maleate). In both patients, changes in regional CBF occurred that were larger than those seen in nine normal controls. One patient experienced an improvement in regional CBF with a reduction in probe pair asymmetry. In the other patient, who had bilateral carotid artery disease, a decrease in regional CBF in all 16 probes (mean decrease 12 percent) and an accentuation of the predose asymmetry were observed. Both patients remained asymptomatic throughout the study. Assessing these effects on cerebral circulation may help identify patients at risk for iatrogenic focal cerebral ischemia and provide information regarding the functional status of the cerebral vasculature.
Fagan
S C
SC
College of Pharmacy, Wayne State University, Detroit, MI 48202.
Ewing
J R
JR
Levine
S R
SR
Tietjen
G E
GE
Ramadan
N M
NM
Welch
K M
KM
D000368:Aged; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000503:physiopathology*; D002340:Carotid Artery Diseases / Q000150:complications / Q000503:physiopathology*; D002343:Carotid Artery, Internal; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004656:Enalapril / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D011224:Prazosin / Q000008:administration & dosage / Q000494:pharmacology*
D004656:Enalapril; D011224:Prazosin