Abnormal pressure passive dilatation of cerebral arterioles in the elderly with isolated systolic hypertension.
The aim of this study was to investigate the cerebrovascular adaptability to 2 sequential pressor stimuli in elderly patients with isolated systolic hypertension. Ten healthy elderly normotensive subjects (68 to 82 years), 10 elderly subjects with isolated systolic hypertension (63 to 82 years), and 10 young normotensive subjects (24 to 40 years) took part in the study. A pressor reaction, using sequential cold pressor and handgrip stimulation, was induced. The cerebrovascular response to the pressor stimulation was measured by transcranial Doppler determination of the mean flow velocity in the middle cerebral arteries. In all of the subjects, blood pressure increased during handgrip (+12 mm Hg, P<0.001 in the young; +18 mm Hg, P<0.01 in the elderly normotensive subjects; +19 mm Hg, P<0.001 in the hypertensive patients versus baseline). In the hypertensive subjects, the pressure increase persisted well into the recovery period. The pressure increase caused a significant increase in mean flow velocity in the middle cerebral arteries only in the elderly subjects. Cold pressor test increased blood pressure in all of the subjects during stimulation and the first 2 minutes of the recovery period (at whole-curve ANOVA: F=22.03, P<0.001 in the young participants; F=18.3, P<0.001 in the normotensive elderly; and F=13.04, P<0.001 in the hypertensive elderly). Mean flow velocity in the middle cerebral arteries significantly increased only in the hypertensive subjects. In the elderly hypertensive patients, the cerebrovascular reaction to adrenergic stimuli was more impaired than in the elderly normotensive subjects. This event can amplify the pressure insult on cerebral hemodynamics and increase the predisposition to cerebral damage, such as vascular cognitive impairment or stroke.
Castellani
Sergio
S
Institute of Internal Medicine and Cardiology, Department of Critical Care Medicine and Surgery, University of Florence, and Azienda Ospedaliera-Universitaria Careggi, Florence, Italy. sergio.castellani@unifi.it
Bacci
Marzia
M
Ungar
Andrea
A
Prati
Patrizio
P
Di Serio
Claudia
C
Geppetti
Pierangelo
P
Masotti
Giulio
G
Neri Serneri
Gian Gastone
GG
Gensini
Gian Franco
GF
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001160:Arterioles / Q000503:physiopathology; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003080:Cold Temperature; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D020768:Middle Cerebral Artery / Q000503:physiopathology*; D013599:Systole; D014661:Vasoconstriction / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*