OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY (OCTA) METRICS PREDICT INTRADIALYTIC HYPOTENSION EPISODES IN CHRONIC HEMODIALYSIS PATIENTS: A PILOT, PROSPECTIVE STUDY

Abstract Background and Aims In chronic hemodialysis (HD) patients, intradialytic hypotension (IDH) is a complication that increases mortality risk. The pathogenesis of this condition remains partly unexplained although dysfunctions of the nervous autonomous system and various factors related to the hemodialytic procedure like rapid or excessive ultrafiltration, excessive reduction in osmolality and reaction to the dialyzer membrane or machine tubing, seem to play a key role. The observation of ocular microcirculation gives us an exceptional chance to directly evaluate in vivo the reactions of human circulation to stress stimuli. Indeed, the ocular microcirculation is involved in systemic disease and early changes in vascular structures may predict the development of systemic vascular disorders. We run a pilot study to analyzing possible relationships between optical coherence tomography angiography (OCT-A) metrics and IDH and to evaluate whether OCT-A could represent a useful tool to stratify the hypotensive risk in dialysis patients. Method a total of 35 eyes (35 patients) being correctly analyzed. OCT-A was performed before and after a single dialysis session. Patients were then followed up to 30 days (10 HD sessions) and a total of 73 IDHs were recorded with 12 patients (60%) experiencing at least one IDH. Results Central choroid thickness (CCT), 6x6 mm whole vessel density (VD) of superficial capillary plexus (SPC) and 6x6 mm foveal VD of deep capillary plexus (DCP) were reduced after dialysis (Figure 1). At logistic regression analysis, IDH was positively associated with baseline foveal VD of SCP and DCP, while an inverse association was found with the choroid (Figure 2). In Kaplan-Meier analyses of patients categorized according to the ROC-derived optimal thresholds, CCT, the 3x3 foveal VD of SCP, the 3x3 mm and 6x6 mm foveal VD of DCP and the 6x6 mm foveal VD of SCP were strongly associated with a higher risk of IDH over the 30-days follow-up. Conclusion In our study, we demonstrated that HD patients experiencing frequent IDH episodes showed a different ocular pattern with respect to those not facing with this complication. Furthermore, a simple measurement of retinal and choroid parameters by OCT-A before a single dialysis session may help predicting the risk of following IDH in the short-term. In HD patients, a single OCT-A measurement may represent a non-invasive, rapid tool to evaluate the compliance of vascular bed to HD stress and to stratify the risk of IDH in the short term.