The potential of optical coherence tomography angiography in progressive multiple sclerosis

Early detection and monitoring of neurodegenerative processes in persons with multiple sclerosis (PwMS) is currently a major challenge. Optical coherence tomography angiography (OCTA) is an emerging method to visualize retinal vascular architecture. However, its use has mainly been investigated in relapsing MS. We evaluated OCTA as a possible complementary method in progressive MS (PMS) in a monocentric, retrospective, cross-sectional study. Eyes with evidence of optic neuritis were excluded from analysis. OCTA images acquired using a Spectralis OCT (Heidelberg Engineering) were analyzed with an established deep learning-based segmentation algorithm. After rigorous quality control, 85 eyes of 62 PwPMS were compared with 64 eyes of 43 age and gender-matched healthy controls (HC). The vessel density in the superficial vascular complex (VD_SVC (%)) was reduced in PMS compared to HC (p = 0.018). VD_SVC correlated negatively with age in PwPMS and HC. Using a Johnson-Neyman analysis, we identified that the disease duration influences the VD_SVC in PMS individuals < 57.5 years of age. PwPMS with disease duration > 10 years had reduced VD_SVC compared to subjects with ≤ 5 years of disease duration (p = 0.049) (corrected for age). Clinical disability (EDSS) negatively correlated with VD_SVC in PwPMS (β = -0.487, p = 0.010). These results suggest that OCTA might be suitable to detect retinal vascular changes in PwPMS. One consequence could be structured and harmonized OCTA investigations as part of routine clinical practice. External validation and longitudinal studies are necessary to further elaborate OCTA´s potential in monitoring PwPMS.