NOCTURNAL BLOOD-PRESSURE AND SILENT CEREBROVASCULAR LESIONS IN ELDERLY JAPANESE

Background and Purpose We conducted a cross-sectional epidemiological survey using ambulatory blood pressure monitoring and brain MRI in a c ohort from northern Japan to determine whether an inappropriately low nocturnal blood pressure, or an excess fall in nocturnal blood pressur e, might be responsible for silent cerebrovascular lesions in the elde rly. Methods Untreated subjects over 55 years and under 64 years of ag e (late middle age; 24 men and 46 women, 60% of eligible people) and o ver 65 years and under 75 years of age (elderly; 29 men and 52 women, 91% of eligible people) participated in the study. We evaluated the re lationship between the amplitude (Daytime Average-Nighttime Average) o r the rate ([Daytime Average-Nighttime Average]/Daytime Average) of th e fall in nocturnal blood pressure and the incidence of silent cerebro vascular lesions on MRI (number of lacunar infarctions or extent of pe riventricular hyperintensity). Results The amplitude or the rate of th e fall in nocturnal blood pressure in elderly women with one or two la cunar infarctions was significantly higher than that in those without such infarctions. There was a significant positive correlation between the amplitude or the rate of the fall in nocturnal blood pressure and the extent of periventricular hyperintensity in the elderly women. Th is relationship was observed in women, but not in men, of late middle age; this was not seen in elderly men. Conclusions Results indicate th at an inappropriately low nocturnal blood pressure, or an excessive fa ll in nocturnal blood pressure, is associated with ischemic silent cer ebrovascular lesions, at least in elderly women. Treatment of hyperten sion in such women should be administered with care and with regard to nocturnal blood pressure.