Abstract 2403: Reproducibility and Consequence of Orthostatic Hypertension Detected by Self-measured Home Blood Pressure Monitoring, and its Control by Alpha-adrenergic Blockade
Objective: Orthostatic blood pressure (BP) dysregulation is a risk factor for falls and cardiovascular events. Self-measured BP at home is highly reproducible, and is useful for evaluating antihypertensive treatment. However, there have been few reports on the clinical implications of orthostatic BP change in home BP measurement (HBPM).
Methods: We developed a new semi-automatic HPBM device (Japan Patent Office No. 2002–307787) to semiautomatedly measure orthostatic BP change at home, and compared orthostatic BP changes measured at home and by a head-up tilt test (HUT) in 65 hypertensive subjects. In addition, we recruited 611 medicated hypertensive outpatients in a part of Japan Morning Surge-1 (JMS-1) study, and monitored home BP in the sitting and standing positions both in the morning and evening for 6 months. An independent study control center randomly allocated these patients to the experimental group, who received bedtime administration of doxazosin (1– 4 mg, DOX group), or to the control group, who continued without any add-on medication.
Results: Orthostatic BP change evaluated using the HPBM device was positively correlated with orthostatic BP change evaluated by the HUT (r=0.49, p<0.001). Monthly value of baseline home BP level in sitting position and orthostatic BP change were reproducible over 6 months (r=0.61– 0.72, p<0.001). When the patients were divided into 10 groups according to orthostatic BP change, those in the top decile (n=60: orthostatic BP increase ≥ 7.5mmHg) had a higher urinary albumin excretion (UAE) than the others (geometric mean: 57.5 vs. 27.7 mg/gCre, p<0.001, adjusted for age, sex, body mass index, and home sitting BP level. In DOX group, orthostatic BP change (13±3.8 vs. 1.0±11mmHg, p<0.001) and UAE (geometric mean: 78.1 vs. 42.7mg/gCre, p<0.001) of the top decile group were significantly reduced.
Conclusion: Orthostatic BP change detected by self-measured home BP monitoring is highly reproducible, and orthostatic hypertension evaluated at home was associated with hypertensive target organ damage independently of home sitting BP level. Administration of doxazosin might suppress orthostatic hypertension and consequently prevent target organ damage.