title: Intensive blood pressure lowering increases cerebral blood flow in older subjects with hypertension.
abstract: Hypertension is associated with reduced cerebral blood flow (CBF). Intensive (<130/80 mm Hg) blood pressure (BP) lowering in older people might give greater reduction in cardiovascular risk, but there are concerns that this might produce hypoperfusion which may precipitate falls and possibly stroke. We determined the effect of intensive compared with usual BP lowering on CBF in hypertensive older subjects. Individuals aged >70 years with a history of systolic hypertension on 1 or no BP lowering drugs were recruited from primary care (n=37; age, 75±4 years; systolic BP, >150 mm Hg) and randomized to receive intensive (target BP, <130/80 mm Hg) or usual (target BP, <140/85 mm Hg) BP lowering for 12 weeks, with reviews every 2 weeks. CBF, determined using 3T arterial spin labeling MRI, and 24-hour ambulatory BP were performed at baseline and after 12 weeks of treatment. Baseline BP (ambulatory or in clinic) and baseline gray matter CBF were not significantly different between the groups. After treatment, BP was reduced significantly in both groups but fell more in the intensive group (26/17 versus 15/5 mm Hg; P<0.01). Over the same period, gray matter CBF increased significantly in the intensive group (7±11 mL/min per 100 g; P=0.013) but was unchanged in the usual BP target group (-3±9 mL/min per 100 g; P=0.23); P<0.01 for comparison. Intensive BP lowering in older people with hypertension increases CBF, compared with BP lowering to usual target. These findings suggest hypertension in older people shifts the autoregulatory CBF curve rightward and downward and is reversible with BP lowering.
authors.affiliation: Institute for Ageing and Health, Newcastle University, Stroke Research Group, Level 6, Leazes Wing, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, UK.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Tryambake
authors.forename: Jiabao
authors.initials: J
authors.lastname: He
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Firbank
authors.forename: John T
authors.initials: JT
authors.lastname: O'Brien
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Blamire
authors.forename: Gary A
authors.initials: GA
authors.lastname: Ford
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D001921:Brain / Q000098:blood supply* / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D012039:Regional Blood Flow / Q000187:drug effects* / Q000502:physiology; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents
keywords: MRI; aging; blood flow; blood pressure; cardiovascular disease