Optical Coherence Tomography Angiography in Patients with Systemic Lupus Erythematodes

PURPOSE: Systemic lupus erythematodes (SLE) is a connective tissue disorder with multisystem involvement that leads to an immune complex-mediated angiopathy with deposition in the endothelial cells of small blood vessels. The purpose of this study was to analyse the retinal vasculature, using optical coherence tomography angiography (OCTA) in patients with SLE.

METHODS: This is a single-institution cross-sectional study. Macular OCTA images (6 × 6 and 3 × 3 mm) were acquired in healthy controls (HC) and patients with SLE. En face images of the retinal vasculature were generated from the superficial and deep capillary plexus (SCP/DCP). The vessel density (VD) and vessel length density (VLD) were measured by previously published methods. VD was assessed as the ratio of the retinal area occupied by vessels. VLD was measured as the total length of the skeletonised vessels using 1-pixel center line extraction of the blood vessels. Quantitative analysis of the VD, VLD, and the foveal avascular zone FAZ was performed.

RESULTS: 25 patients (49 eyes) with clinically established SLE and 80 eyes of 66 healthy controls (HC) were included. Among the patients with SLE, the mean age was 41.47 (± 9.27 SD) years with 92% female patients and in the healthy individuals 37.1 years (± 14.33 SD) with 56% female patients. The mean VD of the SCP in the SLE-group was 0.34 ± 0.02, the VLD of SCP was 17.08 ± 1.58 mm^-1, the VD of DCP was 0.28 ± 0.03 and the VLD of DCP was 14.21 ± 1.76 mm^-1 in the 3 × 3 mm scans. In the control group, the mean VD of SCP was 0.36 ± 0.03, the VLD of SCP was 17.50 ± 1.97 mm^-1, the VD of DCP was 0.31 ± 0.04 and the VLD of DCP was 15.86 ± 4.19 mm^-1. There was a statistically significant reduction in both VD of SCP and DCP and of the VLD of the SCP in SLE group (p < 0.05) compared to controls.

CONCLUSIONS: Swept-source OCTA of the microcirculation in eyes of patients with SLE can be used to quantitatively demonstrate a reduction in VD in SCP and DCP and VLD in SCP compared to healthy eyes. The reduction of the capillary network in the superficial and deep capillary plexus indicates an association with SLE disease status and future longitudinal studies may use these metrics to evaluate changes over time and its correlation to disease severity. Further studies are warranted to evaluate the relevance of these microvascular alterations in the setting of SLE and its correlation to disease severity.