Association of blunted nocturnal blood pressure dip with intracerebral hemorrhage

OBJECTIVES: Nondipping pattern of nocturnal blood pressure is associated with silent ischemic cerebrovascular lesions and lacunar infarctions. In this case-control study, we aimed to evaluate the association of diurnal blood pressure variation with the occurrence of intracerebral hemorrhage. METHODS: Ambulatory blood pressure monitoring was performed at 21-28 days after ictus in 78 first-ever unselective consecutive patients with intracerebral hemorrhage and in 80 age-adjusted and sex-adjusted controls who were referred to the hypertension center of our institution. The degree of nocturnal blood pressure dip was calculated as [(mean daytime values-mean night-time values)/mean daytime values]x100. Nondippers were defined as patients who exhibited a <10% nocturnal dip in systolic blood pressure. Logistic regression models were constructed to assess the association of nondipping status with intracerebral hemorrhage after adjusting for potential confounders (cardiovascular risk factors, office and ambulatory blood pressure levels). RESULTS: Prevalence of nondipping was significantly greater among cases than among controls (74.4% vs. 43.8%, P<0.001). Nondipping status was independently (P=0.033) associated with intracerebral hemorrhage (OR: 2.326, 95% CI: 1.068-5.050) in a multiple variable logistic regression model that adjusted for baseline characteristics, cardiovascular risk factors, office and ambulatory blood pressure variables. The magnitude of the nocturnal systolic blood pressure dipping was inversely related to the risk of intracerebral bleeding; the odds ratio for intracerebral hemorrhage associated with every 1% decrease in nocturnal systolic blood pressure dip was 1.143 (95% CI: 1.058-1.235, P=0.001). CONCLUSIONS: Given the previous reports that nondipping contributes to the risk of cerebral infarction, our results indicate that blunted nocturnal blood pressure dip may be also associated with the occurrence of intracerebral hemorrhage.