title: Losartan, an angiotensin II (AT1) receptor antagonist, preserves cerebral blood flow in hypertensive patients with a history of stroke.
abstract: In patients with severe hypertension, chronic heart failure or a history of stroke, the lower limit of autoregulation of cerebral blood flow (CBF) is shifted to higher levels of blood pressure (BP) than those observed in healthy subjects. The aim of pharmacotherapy for hypertensive patients with an impaired autoregulation of CBF should be to reduce BP while preserving an appropriate CBF. In the present study, 16 hypertensive patients who had had an episode of stroke more than 4 weeks previously were administered the angiotensin II (AT1) receptor antagonist losartan at daily doses of 25-100 mg for 4 weeks. Systolic and diastolic blood pressures were recorded for 24 h using an ambulatory BP monitoring system. CBF in both hemispheres of the cerebrum and cerebellum was quantified using single photon emission tomography with N-isopropyl-p-[123I]iodoamphetamine. At baseline, CBF was 29.7 +/- 6.7 ml/min/100 g in the cerebrum and 31.5 +/- 7.5 ml/min/100 g in the cerebellum. At the end of treatment, BP was lower, while CBF increased by 7.7% in the cerebrum, and remained at the baseline level in the cerebellum. Thus, CBF was preserved despite the reduction in BP. We consider the use of losartan is advantageous for hypertensive patients with a history of stroke in whom autoregulation of CBF is potentially impaired.
authors.affiliation: Department of Cerebrovascular Medicine, National Cardiovascular Center, Suita, Osaka, Japan. hmoriwa@hsp.ncvc.go.jp
authors.forename: H
authors.initials: H
authors.lastname: Moriwaki
authors.forename: H
authors.initials: H
authors.lastname: Uno
authors.forename: Y
authors.initials: Y
authors.lastname: Nagakane
authors.forename: K
authors.initials: K
authors.lastname: Hayashida
authors.forename: K
authors.initials: K
authors.lastname: Miyashita
authors.forename: H
authors.initials: H
authors.lastname: Naritomi
mesh_terms: D000368:Aged; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D018660:Blood Pressure Monitoring, Ambulatory; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D020367:Iofetamine; D019808:Losartan / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D020521:Stroke / Q000150:complications / Q000188:drug therapy*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D016896:Treatment Outcome
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D019275:Radiopharmaceuticals; D020367:Iofetamine; D019808:Losartan