Orthostatic Hypertension: Another Orthostatic Disorder to Be Aware Of

To the Editor: Orthostatic dysregulation of blood pressure is a disorder observed commonly in older people., – Orthostatic hypotension has become the focus of much research, since epidemiological studies have revealed that orthostatic hypotension is associated with increased risk of death. Less attention has been paid, however, to the finding of orthostatic hypertension in routine examinations. Recently, an association between orthostatic increase in blood pressure and higher predicted risk of developing coronary heart disease was reported in the ARIC study. In addition, orthostatic hypertension has been demonstrated to be related to cognitive impairment and asymptomatic cerebrovascular damage detected by MRI. These findings suggest that orthostatic dysregulation of blood pressure may be associated with atherosclerosis, although recent study has revealed that orthostatic hypotension was not associated with cognitive deterioration. We evaluated the prevalence of orthostatic dysregulation of blood pressure and its relationship with carotid atherosclerosis in 154 community-dwelling healthy subjects aged 65 years and older and free from any history or symptoms of cardiovascular disease and medications. After 10 minutes of rest in the supine position, brachial blood pressure was measured twice to obtain the mean basal blood pressure during ultrasound measurement of intima-media thickness (IMT) of the common carotid artery. Then blood pressure measurements were repeated at 1 and 3 minutes after standing up, using an automated blood pressure recorder, OMRON HEM-705CP, which fulfills the AAMI criteria for accuracy for both systolic and diastolic pressure. The maximum change in systolic blood pressure (SBP) was obtained for each subject. Twenty-four subjects (15.6%) showed an orthostatic increase of SBP more than 20 mm Hg, and nine subjects (5.8%) showed a more than 20 mm Hg decrease in SBP after standing. The subjects were divided into four groups according to the degree of orthostatic change in SBP. Analysis of variance showed that theie was a significant J-shaped relationship between orthostatic change in SBP and IMT (F(3,150) = 4.00, P = .009) (Figure 1). Stepwise regression analysis for IMT with parameters including age, body mass index, LDL and HDL cholesterol, plasma glucose, basal SBP, and orthostatic change in SBP revealed that orthostatic change in SBP was independently associated with IMT in addition to age, basal SBP, and glucose. These findings suggest that orthostatic hypertension, as well as orthostatic hypotension, is a disorder to be aware of in evaluating the postural change in blood pressure in older people. Values are mean ± SD. Subjects were divided into four groups according to their systolic blood pressure change after standing. Mean IMT was significantly different among the four groups. Number in the box indicates number of subjects.