Does Orthostatic Testing Have Any Role in the Evaluation of the Young Subject With Mild Hypertension?: An Insight From the HARVEST Study

The aim of the study was to assess the clinical significance of the blood pressure (BP) reaction to standing in 1029 stage I hypertensives. Office BP was measured six times in the supine position and six times after 2 min of standing. All subjects underwent 24-h ambulatory BP monitoring, and measurements of 24-h urinary epinephrine and norepinephrine excretion. Echocardiography was performed in 636 patients. With use of mixture analysis we could single out a population with abnormal diastolic BP response to standing (hyperreactors, n = 95). These subjects had a diastolic BP increase from lying to standing of >11 mm Hg. The other subjects were defined as normoreactors (n = 934). Office systolic BP was similar in the two groups. Diastolic BP was lower (91 ± 6 mm Hg v</it> 95 ± 5 mm Hg, P</it> < .0001) and heart rate was higher in the hyperreactors (77 ± 10 beats/min v</it> 75 ± 9 beats/min, P</it> = .004). After adjusting for age, gender, and smoking habits the statistical significance did not change. Adjusted 24-h systolic BP (P</it> = .02) and diastolic BP (P</it> = .02) were higher in the hyperreactors than in the normoreactors. Hyperreactors were characterized by higher cardiac index (3.2 ± 0.8 L/min/m2 v</it> 3.0 ± 0.7 L/min/m2, P</it> = .008 for adjusted values), lower total peripheral resistance (1420 ± 330 dyne/sec/cm-5 v</it> 1600 ± 380 dyne/sec/cm-5, P</it> = .003), and higher urinary norepinephrine output (114.9 ± 80.3 µ</it>g/24 h v</it> 90.6 ± 78.5 µ</it>g/24 h, P</it> = .03). Dimensional echocardiographic data and albumin excretion rate did not differ between the two groups. In conclusion, mixture analysis allowed us to identify a population of young mild hypertensives with exaggerated BP response to standing. Hyperreactors were characterized by higher whole-day BP and by a hyperkinetic hemodynamic pattern as a result of increased sympathetic tone. Am J Hypertens 1997;10:546–551 © 1997 American Journal of Hypertension, Ltd.