Morning blood pressure surge and hypertensive cerebrovascular disease: role of the alpha adrenergic sympathetic nervous system.
BACKGROUND
The morning surge of blood pressure (BP) is associated with alpha-adrenergic activity. We studied the association between the alpha-adrenergic morning surge in BP and silent cerebrovascular disease in elderly patients with hypertension.


METHODS
We conducted ambulatory BP monitoring three times (twice at baseline and after nighttime dosing of the alpha1-blocker doxazosin) in 98 elderly hypertensive patients in whom the presence of silent cerebral infarcts (SCI) was assessed by brain magnetic resonance imaging. The morning BP surge (MBPS) was calculated as the mean systolic BP during the 2 h after waking minus the mean systolic BP during 1 h that included the lowest sleep BP. The alpha-adrenergic MBPS was calculated as the reduction of MBPS by doxazosin.


RESULTS
The prevalence of multiple SCI was higher in the Surge group (top quartile: MBPS > or = 45 mm Hg, n = 24) than in the Nonsurge group (MBPS < 45 mm Hg, n = 74) (54% v 31%, P = .04), and in the higher alpha-adrenergic surge group (top quartile: alpha-adrenergic MBPS > or = 28 mm Hg, n = 25) than in the lower alpha-adrenergic surge group (< 28 mm Hg, n = 73) (68% v 26%, P < .0001). In the Surge group, subjects with higher alpha-adrenergic surge (n = 17) had a markedly higher frequency of multiple SCI, whereas none in the lower alpha-adrenergic surge group had multiple SCI (n = 7) (77% v 0%, P = .001). The alpha-adrenergic MBPS was closely associated with multiple SCI (10 mm Hg increase: OR = 1.96, P = .006), independently of age, MBPS, 24-h systolic BP, and other confounding factors.


CONCLUSIONS
The morning BP surge, particularly that dependent on alpha-adrenergic activity, is closely associated with advanced silent hypertensive cerebrovascular disease in elderly individuals.
Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical School, Tochigi, Japan. kkario@jichi.ac.jp
Kazuomi
K
Kario
Thomas G
TG
Pickering
Satoshi
S
Hoshide
Kazuo
K
Eguchi
Joji
J
Ishikawa
Masato
M
Morinari
Yoko
Y
Hoshide
Kazuyuki
K
Shimada
D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage; D000368:Aged; D000375:Aging; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D020520:Brain Infarction / Q000453:epidemiology / Q000473:pathology; D002940:Circadian Rhythm; D017292:Doxazosin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology*
D000317:Adrenergic alpha-Antagonists; D017292:Doxazosin