OP0311 DETECTION OF SUBCLINICAL SKIN MANIFESTATION IN PATIENTS WITH PSORIASIS AND PSORIATIC ARTHRITIS BY FLUORESCENCE OPTICAL IMAGING
Authors: A. Schmidt, A. M. Glimm, P. Hoff, G. Schmittat, G. R. Burmester, J. Klotsche, S. Ohrndorf
Journal: Annals of the Rheumatic Diseases (2020)

Background: Fluorescence optical imaging (FOI) as new imaging technique enables visualization of an impaired microcirculation in both hands caused by joint inflammation. A detection of psoriatic skin inflammation which may also signify an altered vessel composition via FOI has not yet been examined. Objectives: The aim of the present study was to investigate potential subclinical skin inflammation in both hands of psoriasis (Pso) and psoriatic arthritis (PsA) patients in comparison to rheumatoid arthritis (RA) and healthy individuals by FOI, and to correlate these findings with cardiovascular risk factors or events, since a connection to Psoriasis skin involvement is assumed. Methods: FOI scans of patients with Pso and PsA as well as RA and healthy subjects were analyzed retrospectively to detect subclinical skin enhancement in both hands that did not clinically show overt psoriasis skin changes. According to the ‘fluorescence optical imaging activity score’ (FOIAS) (1) used for evaluation of joint enhancement so far, a standardized definition was set in order to describe the degree of skin enhancement via a semi-quantitative (0-3) score (see Figure ). The score was applied for the first third of the FOI exam sequence (0-120 sec.). To be scored as potential subdermal skin enhancement, it had to be localized on the back of the hands without relationship to an underlying joint or blood vessel since the ICG enhancement was then most likely localized in the area of the (sub)dermis. Using this analysis method, we further characterized the patterns and sorted the scans into the groups PsA/Pso, RA and healthy controls to compare these with the final physician’s diagnosis. Furthermore, cardiovascular risk factors (e.g. obesity, smoking status, hypertension) were collected and correlated to imaging findings. Results: We included FOI scans of patients with PsA/Pso (n=80), patients with RA (n=78) and healthy controls (n=25). Significantly more PsA/Pso patients showed subclinical skin enhancement on the back of their hands than RA and healthy individuals (PsA/Pso: 72.5%, RA: 20.5%, healthy controls: 28.0%; p&lt;0.001). By using the pattern of skin enhancement, it was possible to categorize 58 of 80 patients correctly as PsA/Pso (72.5%), 60 out of 78 as RA (76.9%) and seventeen out of 25 as healthy controls (68.0%; p-value &lt;0.001). We could show an influence of the body weight (kg) (p&lt;0.001, OR 1.04, CI 1.02; 1.06) on the FOI results; no further correlation with cardiovascular risk factors was detected. Conclusion: We were able to proof our primary hypothesis that it is possible to visualize subclinical subdermal skin inflammation in PsA/Pso patients using FOI. Furthermore, we were also able to categorize PsA/Pso and RA patients correctly by using our newly developed method. Although we could not establish a correlation between subdermal skin enhancement and cardiovascular risk factors, we demonstrated an important influence of the body weight on our FOI results. FOI may be a helpful novel tool to study microcirculation in rheumatic diseases with skin involvement. References: [1]Werner SG, et al. Inflammation assessment in patients with arthritis using a novel in vivo fluorescence optical imaging technology. Ann Rheum Dis. 2012;71(4):504-10. Figure. Left picture: The enhancement is mostly yellow on green ground classified as grade 1. Middle picture: The enhancement is red with minimal white signals classified as grade 2. Right picture: The enhancement in the marked area shows more white than red signals which presents grade 3. Disclosure of Interests: Angelique Schmidt Speakers bureau: Speakers fee from Novartis, Roche, Abbvie, BMS, Anne-Marie Glimm: None declared, Paula Hoff: None declared, Gabriela Schmittat: None declared, Gerd Rüdiger Burmester Consultant of: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Speakers bureau: AbbVie Inc, Eli Lilly, Gilead, Janssen, Merck, Roche, Pfizer, and UCB Pharma, Jens Klotsche: None declared, Sarah Ohrndorf: None declared