Association of Postural Blood Pressure Response With Disease Severity in Primary Open Angle Glaucoma.

PRCIS: Patients with primary open angle glaucoma (POAG) demonstrated exaggerated postural blood pressure dip in recumbency that was positively correlated with the severity of glaucomatous optic neuropathy (GON). Postural dip testing can be used clinically as a marker of systemic vascular dysregulation in GON risk assessment. OBJECTIVE: To investigate whether patients with POAG demonstrated abnormal postural blood pressure response to recumbency and whether such abnormal postural response correlated with GON severity. PATIENTS AND METHODS: This is a prospective observational study where 47 patients with POAG underwent intraocular pressure and systemic arterial blood pressure, systolic blood pressure (SBP) and diastolic blood pressure (DBP), measurement in seated and after 20-minute recumbency positions. Mean arterial blood pressure (MABP) was calculated for seated and recumbent positions. The percentage difference between seated and recumbent SBP, DBP, and MABP was calculated according to which participants were divided into 3 groups, that is, nondippers, normal dippers, and exaggerated dippers with percentage dips of <10%, ≥10%≤20%, >20%, respectively. Participants underwent optical coherence tomography of optic nerve head to measure retinal nerve fiber layer thickness (RNFLT) which was used as a structural biomarker of GON. RESULTS: RNFLT was lower in exaggerated dippers than in nondippers and normal dippers. There was a negative correlation between postural dip and average RNFLT. Linear regression showed that postural dip was associated with lower RNFLT independent of age and intraocular pressure. The χ 2 independence test demonstrated a strong relation among corresponding dip groups for SBP, DBP, and MABP. However, it showed no significant relation between hypertension and postural dip. Fisher exact test showed no relation between antihypertensive medication and postural dip. CONCLUSIONS: Patients with POAG demonstrated abnormal postural blood pressure response comprising exaggerated recumbent dip which was positively correlated with disease severity. Postural dip assessment may serve as a simple clinic-based test of systemic vascular dysregulation as part of GON risk evaluation.