Relationship between extreme dippers and orthostatic hypertension in elderly hypertensive patients.

Abstract

Among elderly hypertensive subjects, extreme dippers with marked nocturnal fall in blood pressure (BP) as well as nondippers with absent nocturnal fall in BP are more prone to cerebrovascular disease when compared with those with appropriate nocturnal BP fall. However, the relationship between these abnormal diurnal BP variation patterns and postural BP variation has not been investigated. We investigated the diurnal BP variation by ambulatory BP monitoring and postural BP variation during 70 degrees head-up tilt in 110 asymptomatic hypertensive elderly subjects, who consisted of 29 subjects with white-coat hypertension and 81 with sustained hypertension with various patterns of nocturnal fall in BP (14 extreme dippers, with asleep systolic BP decrease by > or =20% of awake systolic BP; 56 dippers, with decrease by > or =0% to <20%; 11 nondippers, with decrease by <0%). During tilt, the mean (SD) systolic BP increased 10 (19) mm Hg in the extreme dippers (P<.02), and it decreased by 7.5 (13) mm Hg in the nondippers (P<.05), whereas it did not change in the dippers and white-coat hypertensive subjects. The heart rate increased in all four groups to similar degrees during tilt. Orthostatic hypertension defined as systolic BP rise of 10 mm Hg or more during tilt was found in 10 (72%) of the 14 extreme dippers, 6 (11%) of the 56 dippers, and 1 (9%) of the 11 nondippers, while orthostatic hypotension defined as systolic BP decrease of 20 mm Hg or more was found in 3 (27%), 5 (9%), and 1 (7%) of the nondippers, dippers, and extreme dippers, respectively (chi2=29.3, P<.0001). In conclusion, the abnormal diurnal BP variation is closely related to the abnormal postural BP variation in elderly hypertensive patients, with extreme dippers showing orthostatic hypertension and nondippers showing orthostatic hypotension. The upright position during the daytime, which increases the BP in the extreme dippers and decreases it in the nondippers, may in part produce abnormal diurnal BP variation.