Association of blood pressure elevation and nocturnal dipping with brain atrophy, perfusion and functional measures in stroke and nonstroke individuals.

BACKGROUND: Although both blood pressure elevation and lower nocturnal dipping increase vascular risk, it is not known whether either or both are also associated with brain atrophy, cerebral perfusion, and functional status.
METHODS: We investigated the association of elevated blood pressure and nocturnal dipping based on 24-h ambulatory recordings with brain atrophy and perfusion and functional status in 80 older adults with and without stroke (age 66.4 +/- 0.8 years, 51% women, 16% nonwhite, 46% prior ischemic stroke, 55% hypertension). Anatomical and three-dimensional continuous arterial spin labeling (CASL) brain magnetic resonance imaging (MRI) measuring volumes and perfusion and 24-h ambulatory blood pressure readings were completed.
RESULTS: Nocturnal dipping of lesser magnitude in systolic (nonstroke: P = 0.03; stroke: P = 0.005) and pulse pressure (PP; nonstroke: P = 0.002; stroke: P = 0.01) was associated with greater brain atrophy, affecting preferentially the fronto-parietal regions. Dipping of lesser magnitude in systolic blood pressure (SBP; nonstroke: P = 0.01; stroke: P = 0.03) and greater brain atrophy (nonstroke: P = 0.04; stroke: P = 0.05) were also associated with slower gait speed and worse functional outcome after stroke. Higher 24-h blood pressure averages were associated with lower cerebral perfusion but not atrophy in those with and without stroke.
CONCLUSIONS: In those with and without stroke, dipping of lesser magnitude in systolic and PP is associated with brain atrophy and worse functional status. Nocturnal dipping, in addition to elevated blood pressure, should be considered as an additional important target in the clinical evaluation of those at risk for cerebrovascular disease or functional loss.