REGIONAL CEREBRAL BLOOD-FLOW IN FAMILIAL HYPERCHOLESTEROLEMIA

Background and Purpose Although epidemiologic investigations are tryin g to clarify the role of plasma lipid concentrations (primarily choles terol and its subfractions) as risk factors for both ischemic and hemo rrhagic stroke, little information is available regarding the effect o f sustained hypercholesterolemia on cerebral perfusion. Methods Region al cerebral blood flow (CBF) was measured by the Xe-133 inhalation met hod in 25 heterozygous patients (four untreated) affected with familia l hypercholesterolemia. In 15 patients regional CBF was repeated 20 mi nutes after intravenous administration of acetazolamide (10 mg/kg body wt) to evaluate cerebrovascular reactivity. Correlations among cerebr al perfusion data, present or pretreatment plasma lipid concentrations , and certain other clinical features were assessed by ANOVA. Results Both basal regional CBF and cerebrovascular reactivity were normal in the vast majority of patients compared with age- and sex-matched norma l control subjects. CBF was significantly dependent on pretreatment lo w-density lipoprotein cholesterol (LDL-C) concentration (P=.005) and t he presence of symptomatic ischemic heart disease (P=.015). CBF was on ly slightly dependent on age (P=.05) and was not dependent on either l ipoprotein(a) or present LDL-C concentration. CBF did not differ betwe en treated and untreated patients, and the perfusional increase induce d by acetazolamide was not related to any other variable. Conclusions Cerebral perfusion and cerebrovascular reactivity were maintained with in the normal range despite longlasting, severe hypercholesterolemia, even if a somewhat lower CBF was found in those patients with the high est LDL-C pretreatment levels. These results are in accord with the ep idemiologic data that implicate hypercholesterolemia as a minor risk f actor, if a risk factor at all, for intracranial atherosclerosis and i schemic stroke.