Cerebral blood flow changes with diuretic therapy in elderly subjects with systolic hypertension.
It has been feared that lowering the blood pressure (BP) of elderly patients with systolic hypertension (SH) may compromise cerebral perfusion. To test this hypothesis, BP, cerebral blood flow (CBF), plasma renin activity (PRA), blood counts, urinary and serum electrolytes and other blood chemistries were measured in fifteen elderly patients (ages 61-76 years) with SH (systolic BP greater than 170 and diastolic BP less than 100 mmHg). Gray matter flow (Fg) was calculated from clearance curves of inhaled 133-Xenon. All subjects were studied while untreated, as well as during long-term treatment (average 15 weeks) with hydrochlorothiazide. BP fell during treatment from 186/90 to 160/86 while average Fg and cerebrovascular resistance (CVR) were not significantly changed. There was some suggestion, however, that in patients who became normotensive the CVR decreased (p less than 0.05) while in those who did not Fg fell (p less than 0.05). Cerebrovascular response to 5% CO2 inhalation was impaired during both the treated and untreated states. Individual changes in Fg and CVR did not correlate with changes in BP or with changes in PRA, electrolytes or other chemistries. In general, cautious, gradual reduction of BP with a thiazide diuretic in SH of the elderly seems not to impair cerebral perfusion, but individual differences exist and further studies are needed to characterize them.
D000368:Aged; D000804:Angiotensin II / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood; D013599:Systole / Q000187:drug effects; D014527:Uric Acid / Q000097:blood
D006852:Hydrochlorothiazide; D000804:Angiotensin II; D014527:Uric Acid; D012083:Renin; D011188:Potassium