Retinal microvasculature damage associated with orthostatic hypotension in Parkinson’s disease

Abstract Orthostatic hypotension (OH) is a common non-motor symptom in Parkinson’s disease (PD). OH can cause cerebral and retinal hypoperfusion and is associated with microvascular damage in PD. Optical coherence tomography angiography (OCTA) is a non-invasive technology that can be used to visualise the retinal microvasculature and detect the microvascular damage in PD. In the present study, 51 PD patients (OH+, n = 19; OH−, n = 32) and 40 healthy controls were evaluated. The Unified Parkinson’s Disease Rating Scale (UPDRS) III, Hoehn and Yahr (H&Y) scale, Montreal Cognitive Assessment (MoCA), levodopa equivalent daily dose (LEDD) and vascular risk factors including hypertension, diabetes, and dyslipidaemia, were investigated. The PD patients underwent a head-up tilt (HUT) test. The PD patients had a lower superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP) vessel densities in the central region than controls. The PDOH + group had lower vessel density in the SRCP central region compared with the control group, and lower vessel density in the DRCP central region than the PDOH − and control groups. The changes in diastolic blood pressure (DBP) during the HUT test in PD patients showed a negative correlation with the vessel density in the DRCP central region. The results showed the presence of OH was a critical factor associated with the microvasculature damage in PD. The findings indicate that OCTA can be a useful and non-invasive tool for detecting microvasculature damage in PD patients.