Choroid structure analysis following initiation of hemodialysis by using swept-source optical coherence tomography in patients with and without diabetes

The Impact of a Single Haemodialysis Session on the Retinal Thickness and Optic Nerve Morphology

BACKGROUND

The aim of the study was to assess the influence of a single haemodialysis (HD) session on the retinal and optic nerve morphology in end-stage kidney disease (ESKD) patients.

METHODS

It is a prospective study including only the right eye of 35 chronic kidney disease (CKD) patients subjected to HD. Each patient underwent a full eye examination 30 min before HD (8 a.m.) and 15 min after HD. Optical coherence tomography (OCT) was used to assess the peripapillary retinal nerve fibre layer (pRNFL) thickness, macular nerve fibre layer (mRNFL) thickness, ganglion cell layer with inner plexiform layer thickness (GCL+), GCL++ (mRNFL and GCL+) thickness, total retinal thickness (RT) and total macular volume (TMV). The correlation was tested between such systemic parameters changes as systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), body weight, plasma osmolarity and ocular perfusion pressure (OPP) and ultrafiltration volume with total RT and pRNFL thickness changes during HD.

RESULTS

In the results of a single HD session, we could observe a statistically significant increase in the total RT thickness (pre-HD 270.4 ± 19.94 μm, post-HD 272.14 ± 20.11 μm; p = 0.0014), TMV (pre-HD 7.48 ± 0.53 mm3, post-HD 7.52 ± 0.55 mm3; p = 0.0006), total pRNFL thickness (pre-HD 97.46 ± 15.71 μm, post-HD 100.23 ± 14.7 μm; p = 0.0039), total GCL+ thickness (pre-HD 70.11 ± 9.24 μm, post-HD 70.6 ± 9.7 μm; p = 0.0044), and GCL++ thickness (pre-HD 97.46 ± 12.56 μm, post-HD 97.9 ± 12.94 μm; p = 0.0081). We observed a significant correlation between the change in total RT and DBP change, as well as between body weight change and the change in total pRNFL thickness. There was also a correlation between total pRNFL thickness change and the presence of diabetes mellitus.

CONCLUSION

Even a single HD session affects the retinal and pRNFL thickness, which should be taken into account when interpreting the OCT results in patients subjected to HD. The impact of changes after a single HD session on selected parameters requires further assessment in subsequent studies, including long-term observation.

The Haemodialysis Session Effect on the Choroidal Thickness and Retinal and Choroidal Microcirculation-A Literature Review

Haemodialysis (HD) is currently the most commonly used method of renal replacement therapy. The process of dialysis involves numerous changes that affect many systems, including the eye. The changes occurring in the course of HD may affect the ocular parameters, such as intraocular pressure, central corneal thickness, retinal thickness, retinal nerve fibre layer thickness, and choroidal thickness (CT). The choroid, being one of the most vascularized tissues, is characterized by the highest ratio of blood flow to tissue volume in the entire body, may be particularly susceptible to changes occurring during HD, and at the same time reflect the microcirculatory status and its response to HD. Patients with end-stage renal disease subjected to dialysis are highly susceptible to systemic microvascular dysfunction. Moreover, it is considered that the process of HD itself contributes to vascular dysfunction. Nowadays, thanks to the development of imaging techniques, the widely available optical coherence tomography (OCT) tests allow for the assessment of CT, while OCT-angiography allows for a quick, non-invasive, and repeatable assessment of the condition of retinal and choroidal microcirculation, which significantly expands our knowledge regarding the reaction of ocular microcirculation due to HD. The assessment of both retinal and choroidal circulation is even more attractive because retinal circulation is autoregulated, while choroidal circulation is mainly controlled by extrinsic autonomic innervation. Thus, assessment of the choroidal response to an HD session may provide the possibility to indirectly evaluate the functions of the autonomic system in patients subjected to HD. At a time when the importance of microcirculation in systemic and renal diseases is becoming increasingly evident, the assessment of ocular microcirculation appears to be a potential biomarker for assessing the condition of systemic microcirculation. In this work, we present a review of the literature on the effect of the HD session on CT and the retinal and choroidal microcirculation.

Optical coherence tomography angiography analysis of changes in the retina and the choroid after hemodialysis for end stage kidney disease

PURPOSE

To study effects of hemodialysis (HD) on retinal and choroidal vasculature in patients with end-stage kidney disease (ESKD) using optical coherence tomography angiography (OCTA).

METHODS

In this prospective study, we investigated eyes of patients undergoing hemodialysis for ESKD from Mondor University Hospital. Only one eye/patient was considered. Subfoveal choroidal thickness (SCT) was measured on enhanced-depth imaging optical coherence tomography (EDI-OCT) before and after the hemodialysis session. OCTA was used to extract retinal vascular density (superficial and deep capillary plexus, SCP, DCP) and choriocapillaris non-perfusion. Clinical, demographic and biological parameters (Blood B-Nitric Peptid rate prior to HD session) were reviewed.

RESULTS

Twenty patients (mean age 53.2 ± 13.6 years, 10 males and 10 females) were included in this prospective study. SCT significantly decreased after the HD session (234.3 ± 56.14 µm before HD to 211.9 ± 60.79 µm after hemodialysis (Wilcoxon signed-rank test, p = 0.003)). Non-perfusion in the choriocapillaris significantly increased after HD (41.65 ± 3.58 before HD, 42.95 ± 3.19 after HD, p = 0.036) while no significant modification of the vascular density was observed in the retinal vasculature (SCP, DCP) around the macular zone or the optic nerve. An increased plasma B-Nitric Peptide (BNP) level prior to the onset of the HD session was significantly correlated with the decrease of the SCT (r = 0.45, p = 0.043).

CONCLUSION

Hemodialysis in patients with ESKD is associated with a significant decrease in SCT and an increase in non-perfusion in the choriocapillaris on OCTA. A High BNP level prior to the onset of the hemodialysis appears to be correlated with the decrease in SCT.

Evaluation of an Automated Choroid Segmentation Algorithm in a Longitudinal Kidney Donor and Recipient Cohort

Purpose

To evaluate the performance of an automated choroid segmentation algorithm in optical coherence tomography (OCT) data using a longitudinal kidney donor and recipient cohort.

Methods

We assessed 22 donors and 23 patients requiring renal transplantation over up to 1 year posttransplant. We measured choroidal thickness (CT) and area and compared our automated CT measurements to manual ones at the same locations. We estimated associations between choroidal measurements and markers of renal function (estimated glomerular filtration rate [eGFR], serum creatinine, and urea) using correlation and linear mixed-effects (LME) modeling.

Results

There was good agreement between manual and automated CT. Automated measures were more precise because of smaller measurement error over time. External adjudication of major discrepancies was in favor of automated measures. Significant differences were observed in the choroid pre- and posttransplant in both cohorts, and LME modeling revealed significant linear associations observed between choroidal measures and renal function in recipients. Significant associations were mostly stronger with automated CT (eGFR, P < 0.001; creatinine, P = 0.004; urea, P = 0.04) compared to manual CT (eGFR, P = 0.002; creatinine, P = 0.01; urea, P = 0.03).

Conclusions

Our automated approach has greater precision than human-performed manual measurements, which may explain stronger associations with renal function compared to manual measurements. To improve detection of meaningful associations with clinical endpoints in longitudinal studies of OCT, reducing measurement error should be a priority, and automated measurements help achieve this.

Translational Relevance

We introduce a novel choroid segmentation algorithm that can replace manual grading for studying the choroid in renal disease and other clinical conditions.

Impact of Hemodialysis on Subfoveal Choroidal Thickness Measured by Optical Coherence Tomography: A Systematic Review and a Pooled Analysis of Self-Controlled Case Series

INTRODUCTION

Hemodialysis (HD) has various effects on the body, including optimizing body fluid composition and volume, which may have an impact on subfoveal choroidal thickness (SCT) in individuals with end-stage kidney disease (ESKD). However, previous studies have produced conflicting results regarding the effect of HD on SCT in patients with ESKD. Therefore, we conducted a meta-analysis to investigate the influence of HD on SCT.

METHODS

A comprehensive search of relevant studies and bibliographies was conducted using Embase, PubMed, and Web of Science databases up to September 2022. Weighted mean difference (WMD) and 95% confidence interval (CI) were used to summarize the SCT change. Heterogeneity and publication bias were assessed, and a random-effects model was employed for the meta-analysis. Subgroup analyses were also performed to evaluate the influence of factors such as diabetes mellitus (DM), the severity of diabetic retinopathy (DR), diurnal variation adjustment, optical coherence tomography (OCT) types, and OCT scan modes.

RESULTS

A total of 15 studies involving 1010 eyes were eligible for this meta-analysis, including 552 diabetic eyes, 230 non-diabetic eyes, and the remaining 228 eyes were uncategorized. The meta-analysis revealed a significant reduction in SCT after HD (WMD = -13.66 μm; 95% CI -24.29 to -3.03 μm; z = -5.115, P < 0.0001). Subgroup analysis indicated a significant difference between the DM and non-DM groups (WMD = -24.10 μm vs. -15.37 μm, 95% CI -27.39 to -20.80 μm vs. -19.07 to -11.66 μm; P = 0.001). Additionally, the group with proliferative diabetic retinopathy (PDR) exhibited a more pronounced reduction in SCT (WMD =  -28.66 μm; 95% CI -37.10 to -20.23; z = -6.660, P < 0.0001). Adjusting for diurnal variation, different types or scan modes of OCT did not significantly affect the results.

CONCLUSION

HD leads to a significant decrease in SCT among patients with ESKD, especially in patients with DM with PDR.