Morning blood pressure surge and hypertensive cerebrovascular disease: Role of the alpha adrenergic sympathetic nervous system

Abstract Background The morning surge of blood pressure (BP) is associated with α-adrenergic activity. We studied the association between the α-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 α1-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 α-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 ≥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 α-adrenergic surge group (top quartile: α-adrenergic MBPS ≥28 mm Hg, n = 25) than in the lower α-adrenergic surge group (<28 mm Hg, n = 73) (68% v 26%, P< .0001). In the Surge group, subjects with higher α-adrenergic surge (n = 17) had a markedly higher frequency of multiple SCI, whereas none in the lower α-adrenergic surge group had multiple SCI (n = 7) (77% v 0%, P = .001). The α-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. Conclusion The morning BP surge, particularly that dependent on α-adrenergic activity, is closely associated with advanced silent hypertensive cerebrovascular disease in elderly individuals.