Nocturnal dip in patients with cerebrovascular disease occurring during sleep: prospective assessment by using Ambulatory Blood Pressure Monitoring

ABSTRACT

BACKGROUND:There is little knowledge regarding the possible pathogenetic mechanism of cerebrovascular disease occurring during sleep. We conducted a prospective study using ambulatory blood pressure monitoring to elucidate the specific characteristics and mechanism in cerebrovascular disease occurrence during sleep. METHODS: Stroke were cat-egorized into the small artery disease and large artery disease, cardiogenic disease, and intracerebral hemorrhage. 24- hour ambulatory blood pressure was carried out within 7 days after stroke onset in 20 patients (11 small artery disease, 7 large artery disease, 1 hemorrhage, 1 Moyamoya disease), and in 21 control patients (10 small artery disease, 9 large artery disease, 2 hemorrhage), that were admitted with stroke occuring during awakening time. The mean day-time and night-time systolic and diastolic blood pressure, mean day-time and night-time pulse rate, percentage of nocturnal blood pressure ([mean daytime BP - mean nighttime BP / average BP for the entire 24 hour] x100) were calculated. RESULTS: There was no significant difference between patients with cerebrovascular disease occurring during sleep and controls in mean day-time and night-time systolic and diastolic blood pressure, mean day-time and night-time pulse rate. Absence of normal nocturnal blood pressure dip in all stroke subtypes was noted. But, the magnitude of reduced nocturnal blood pressure decline in small artery disease group was significant smaller than in large artery disease and control groups (p<.005). CONCLUSIONS: Relatively preserved nocturnal blood pressure dip in small artery disease group with cerebrovascular disease occurring during sleep is thought that the cerebral ischemia in this subgroup is produced by excessive falls in the nighttime blood pressure or lowering of night-time blood pressure by antihypertensive agents.