POS1417 CHOROIDAL THICKNESS AS A NOVEL IMAGING MICROVASCULAR BIOMARKER FOR DISEASE PHENOTYPE IN SYSTEMIC SCLEROSIS: INSIGHTS FROM OCTA, LASCA AND NVC ANALYSES
Authors: C. A. Cutolo, E. Hysa, A. Cere, P. Toma, T. Cannavacciuolo, C. Toma, S. Balito, V. Gerli, V. Smith, A. Sulli, S. Paolino, E. Gotelli, C. E. Traverso, M. Nicolò, M. Cutolo
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Systemic sclerosis (SSc) is a complex systemic disease featured by immune dysregulation, vasculopathy and fibrosis. The identification of disease phenotypes through the clinical, autoantibody and microvascular profiles might help stratifying patients and target treatment. From a vascular perspective, the involvement of the ocular microcirculation has been described in SSc but its correlations with clinical clusters and peripheral microcirculation, assessed with nailfold capillaroscopy (NVC) and laser speckle contrast analysis (LASCA), has been minimally explored [1]. <h3>Objectives:</h3> We compared Optical Coherence Tomography Angiography (OCTA) variables in SSc vs age- and sex- matched healthy controls (HCs). OCTA data were correlated with the clinical phenotype of patients with SSc and with the morphological peripheral microvascular status, assessed by NVC, and the functional perfusion, analysed by LASCA. We aimed also to evaluate the performance degree of the combination of OCTA +/- LASCA as classifiers to distinguish patients with limited (lcSSc) and diffuse cutaneous systemic sclerosis (dcSSc), subdivided as per Leroy's criteria [2]. <h3>Methods:</h3> We included 35 SSc patients (mean age 62.4 ± 11.7 years, mean disease duration 8.4 ± 5 years) and 35 HCs in a single centre from March to October 2022. The patients were classified by the ACR/EULAR 2013 criteria, and the assessments were performed, at the same day, including ophthalmological examinations, OCTA, NVC and LASCA. Patients were under standard treatment for SSc and those requiring endovenous prostanoids were evaluated for the study assessment at least one month after the last infusion. <h3>Results:</h3> DcSSc patients exhibited a lower choroidal perfusion (p=0.03) but an increased choroidal thickness (CT) than lcSSc (306 ± 43 µm vs 172 ± 63 µm, p &lt; 0.001, Figure 1). CT was increased also in patients with positive Scl70 antibodies (p = 0.001) and with a history of digital ulcers (p = 0.03) directly correlating with disease duration (r = 0.72, p = 0.001). Significant direct correlations were observed between the mean capillary number (at NVC) and the mean perfusion of fingers (at LASCA) with the retinal and choroidal perfusion (at OCTA) (all p &lt; 0.05). Additionally, a significantly reduced retinal and choroidal perfusion was detected in SSc patients versus controls (all p &lt; 0.05). Interestingly, there were no significant differences between the ocular variables of SSc patients compared to HCs, except for a significantly higher intra-ocular pressure observed in SSc patients (p = 0.006). This increase, however, did not correspond with any change in the thickness of the retinal nerve fiber layer, which remained similar between SSc patients and HCs (p = 0.7). In the context of discerning between patients with dcSSc and lcSSc, only the measurement of the CT exhibited a noteworthy area under the curve (AUC) value of 0.84. A threshold value of 211 μm in CT was identified as the optimal point of demarcation, yielding sensitivity and specificity values of 85% and 69%, respectively, in the differentiation of dcSSc from lcSSc (Figure 2). <h3>Conclusion:</h3> The increased CT, limited to dcSSc and more frequent with longstanding disease, Scl70 positivity and a history of digital ulcers, might be related to the more intense fibrotic process, observed in several tissues of such patients. The altered morphological and functional microvascular status at nailfold correlate with an impairment of the retinal and choriocapillaris microvasculature in SSc patients. This suggests that the ocular microvascular alterations observed in SSc patients mirror the peripheral microvascular involvement, even though these changes may not present with overt clinical symptoms. <h3>REFERENCES:</h3> [1] Kreps et al. Semin Arthr Rheum 2019. [2] LeRoy et al. J. Rheumatol 1988. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>