Background: It remains uncertain which is the stronger predictor for stroke in older hypertensives, ambulatory pulse pressure (PP) or mean blood pressure (MBP).
Methods: We studied the prognosis for stroke in 811 older hypertensives in whom ambulatory BP monitoring was performed. We also assessed silent cerebral infarct (SCI) by brain magnetic resonance imaging.
Results: Silent cerebral infarcts were found in 50% of 515 subjects (64% of the total population) in whom we assessed SCI using brain magnetic resonance imaging. During a mean of a 42-month follow-up period, stroke events occurred in 59 subjects. After adjustment for covariates, for each 10 mm Hg increase in sleep PP, there was an independent 43% (95% confidence interval [CI]:16%-75%, P =.001) increase in the stroke risk, and sleep MBP was not a significant factor after controlling for sleep PP. On the other hand, for each 10 mm Hg increase in awake MBP, there was an independent 48% (95% CI: 21%-81%, P =.0002) increase in the stroke risk, and awake PP was not a significant factor after controlling for awake MBP. After adjusting for SCI (a strong predictor, P <.0001) at baseline, the effects of awake MBP (38% risk increase for each 10 mm Hg, P =.007) and sleep PP (32% risk increase for each 10 mm Hg, P =.016) remained significant.
Conclusions: In older hypertensives, the impacts of PP and MBP on stroke risk are different during sleep and awake periods. Sleep PP and awake MBP are both predictors of stroke events independently of SCI.