Microvascular markers in systemic sclerosis: a comparative OCT-angiography and nailfold videocapillaroscopy study

To investigate the effect of disease duration on retinal microvasculature in patients with systemic sclerosis (SSc), and to explore its correlation with nailfold videocapillaroscopy (NFC) findings and systemic organ involvement. Patients were divided into subgroups according to disease duration (≤5 years, >5 years, <10 years, ≥10 years). Retinal microvasculature was evaluated by OCT-A in the superficial (SCP) and deep (DCP) plexuses, and peripheral microcirculation was assessed by NFC. Correlations between retinal microvascular parameters, disease duration, systemic involvement, and nailfold capillary density were analyzed. This cross-sectional study included 37 SSc patients without retinopathy and 37 healthy controls. The mean duration of disease was 10.5±7.4 (1-30, median: 10.5 years). Central foveal thickness was significantly higher in the SSc group than in controls (p < 0.001). The VD values of SSc patients in both plexuses were significantly lower compared to the healthy control group (p < 0.05, for all). In subgroup analyses, SCP VD was significantly higher in the whole, parafoveal, and perifoveal areas in the SSc-<10y group compared with the SSc-≥10y group (p=0.03, p=0.025, p=0.005). NFC data revealed that the mean capillary number was significantly higher in SSc-<10 y compared to SSc≥10 y (p=0.043). Capillary density was positively correlated with SCP VD (whole; r = 0.606, p < 0.001, parafovea; r=0.487 p=0.002, perifovea, r=0.603 p<0.001). The study findings indicate that SCP-VD may serve as a surrogate quantitative marker of systemic vascular involvement during the progressive course of SSc. OCT-A holds promise as a robust, non-invasive modality for disease monitoring and prognosis.