Influence of the orthostatic decrease in blood pressure and vertebral arterial hemodynamics on orthostatic vertigo

Abstract

Orthostatic vertigo (OV) is believed to occur due to hypoperfusion of the brain with the orthostatic decrease in blood pressure (BP). However, in some cases the orthostatic decrease in blood pressure is not directly involved in the onset of OV. Since the vertebral artery (VA) supplies the central vestibular system, which is involved in the onset of vertigo, we investigated the relationship between the orthostatic changes in blood pressure and the changes in VA hemodynamics to determine whether those could affect the incidence of OV. In 251 subjects, extracranial ultrasonic doppler sonography (ECD) was performed to measure the VA blood flow velocity (VAFV) in the supine and standing position, and we also examined the orthostatic changes in BP. Orthostatic hypotension (OH) was defined as a systolic BP decrease of more than 20 mmHg when standing. All subjects were classified as the OH group and the non-OH group, and the orthostatic decrease in VAFV were evaluated in the cases with OV and without OV about each group, respectively. In the OH group, the cases with OV exhibited a great orthostatic decrease in VAFV compared with those without OV. In the non-OH group, the orthostatic decrease in VAFV was significantly greater in cases with OV than those without OV. These results suggest that the decrease in VAFV induced by standing involves the incidence of OV.