Evaluation of optical coherence tomography angiography findings in anti-neutrophil cytoplasmic antibody-associated vasculitis patients

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides are small vessel vasculitides with a severe course and systemic involvement. It is divided into three subtypes: Granulomatous polyangiitis (GPA), Eosinophilic Granulomatous polyangiitis (EGPA) and Microscopic polyangiitis (1). In ANCA-associated vasculitis, autoantibodies usually develop against Proteinase 3 (PR3) and Myeloperoxidase (MPO), but coexistence of these autoantibodies to both was not been reported. Ninety-five percent of patients with GPA have ANCA positivity at the time of diagnosis, this rate is ninety percent in microscopic polyangiitis and forty percent in EGPA (2). Although ocular involvement is more common in GPA patients, it is usually in the form of anterior segment involvement. The most common findings are conjunctivitis, episcleritis, lacrimal system involvement and retroorbital involvement (3). The aim of the study is to investigate the presence of ocular inflammation accompanying systemic inflammation in ANCA-related vasculitis patients with no previous ocular involvement by optical coherence tomography angiography (OCT-A) and to compare the findings with those of in healthy patients. In the study, OCT (Heidelberg Spectralis), OCTA (Zeiss Angioplex), biometry (ZEISS IOLMaster 700), topography (Corneal Topographer Sirius for Sirius System) examinations were performed for each eye and compared between both groups. Central macular thickness was measured automatically with OCT via the software of the device, and subfoveal choroidal thickness measurement was calculated manually by taking the average of repeated measurements on EDI-OCT enhanced depth imaging. Choroidal vascular index calculation was performed with ImageJ software v 1.51 (National Institutes of Health, Bethesda, MD).. With OCTA, vascular and perfusion densities (mm / mm2 and %) and foveal avascular zone parameters were measured in 6x6 images for the superficial plexus using the software of the device (Angioplex Metrix). Deep capillary plexus vessel densities (mm/mm2) and foveal avascular zone parameters were calculated with ImageJ software v 1.51 (National Institutes of Health, Bethesda, MD). In the study, 104 eyes of 52 patients diagnosed with ANCA-related vasculitis were examined and the date were compared with 104 eyes of 52 participants in the healthy control group. Best-corrected visual acuity was 1.0 in all eyes. Central macular thickness in patients diagnosed with ANCA-related vasculitis was found to be statistically significantly lower than in the control group. Superficial and deep plexus vascular densities and superficial plexus perfusion percentages were found to be lower in patients diagnosed with ANCA-related vasculitis compared to the control group. Foveal avascular zone area and perimeter were higher in the patient group than in the control group. In conclusion, patients with ANCA-related vasculitis without ocular involvement have vascular changes that can be identified by optical coherence tomography angiography.