Blood Pressure Variability and Ocular Vestibular-Evoked Myogenic Potentials Are Independently Associated With Orthostatic Hypotension.

BACKGROUND AND PURPOSE

We delineated the association between otolithic dysfunction and blood pressure (BP) variability.

METHODS

We prospectively recruited 145 consecutive patients (age=71 [59-79] years, median [interquartile range]; 76 females) with orthostatic intolerance between December 2021 and December 2023 at a tertiary hospital in South Korea. Each patient underwent evaluations of cervical and ocular vestibular-evoked myogenic potentials (oVEMPs), 24-h noninvasive ambulatory BP monitoring (ABPM), and a head-up tilt-table test using the Finometer device. As measures of BP variability, the standard deviations (SDs) of the systolic BP (SBP) and the diastolic BP were calculated based on serial ABPM recordings. Patients were divided into those with orthostatic hypotension (OH, =68) and those with a normal head-up tilt-table test despite orthostatic intolerance (NOI, =77) groups.

RESULTS

A multivariable logistic regression analysis showed that OH was associated with bilateral oVEMP abnormalities (=0.021), SBP (=0.012), and female sex (=0.004). SBP was higher in patients with OH than in those with NOI (<0.001), and was not correlated with n1-p1 amplitude (=0.491) or normalized p13-n23 amplitude (=0.193) in patients with OH. The sensitivity and specificity for differentiating OH from NOI were 72.1% and 67.5%, respectively, at a cutoff value of 12.7 mm Hg for SBP, with an area under the receiver operating characteristic curve of 0.73.

CONCLUSIONS

Bilaterally deficient oVEMP responses may be associated with OH regardless of 24-h BP variability, reflecting the integrity of the otolith-autonomic reflex during orthostasis. Alternatively, 24-h BP variability is predominantly regulated by the baroreflex, which also participates in securing orthostatic tolerance complementary to the vestibulo-autonomic reflex.