Ab0805 description in flow in early versus clinically overt systemic sclerosis. laser speckle contrast analysis: a descriptive study on the peripheral blood of the different subtypes of systemic sclerosis

Background

Description of flow, measured by laser speckle contrast analysis (LASCA), in ‘early’ systemic sclerosis (SSc) versus ‘clinically overt’ SSc (diffuse cutaneous SSc [DcSSc] and limited cutaneous SSc [LcSSc]) has not yet been described [1].

Objectives

To investigate in an unselected, SSc cohort if baseline LASCA PBP-measurements differ between ‘early’ SSc and ‘clinically overt’ SSc.

Methods

Between September 2019 and December 2022, patients with SSc (as defined by the 2013 ACR/EULAR criteria and/or the 2001 LeRoy and Medsger criteria) were included [1,2]. A group of 20 consecutive ‘early’ SSc, LcSSc and DcSSc patients were recruited. Vasoactive medication was continued. LASCA was performed at baseline in standardized instrumental and environmental conditions [3]. PBP was assessed by marking regions of interest (ROI’s) with fixed 1 cm diameters at the fingertips of the 2nd through 5th digit volary bilaterally. The adjusted mean PBP was calculated (expressed in perfusion units [PU]). A linear mixed model was fit with a random intercept per patient, together with a linear covariance structure to capture the residual correlations between fingers. Fixed effect terms included subset, side, finger, vasoactive medication, active smoking, history or presence of digital trophic lesions (DTL), and disease duration. Significance level was set at 0.05 and no correction for multiple testing was applied.

Results

Sixty patients with SSc (75% female, mean age 53 years, mean disease duration 73.1 months) were enrolled (table 1). Comparing the adjusted mean PBP at baseline in ‘early’ versus ‘clinically overt’ SSc, no statistical significant difference was found (144 vs. 150 PU, p=0.77) (figure 1A). Additionally within the ‘clinically overt’ group no significant difference was perceived between DcSSc and LcSSc (157 vs. 141, p=0.53). A wide variability was noted when observing the individual measurements of each subset (figure 1B).

Conclusion

This study with an unselected day-to-day SSc population, where patients were allowed to continue their vasoactive medication, showed there was no difference in PBP at baseline between ‘early’ SSc and ‘clinically overt SSc’ when corrected for subset, vasoactive medication, active smoking, history or presence of DTL and disease duration. Interestingly a wide variation of individual datapoints was noted in each subset, which emphasizes the heterogeneity of SSc. In conclusion, there is no inter-individual variation between the different subsets of SSc, as measured with LASCA. Future investigation is needed to enlighten us about the intra-individual changes over time.

References

[1]E.C. LeRoy, T.A. Medsger Jr. J Rheumatol. 2001; 28(7):1573-1576. [2]van den Hoogen F, Khanna D, et al. Arthritis Rheum. 2013;65(11):2737–47. [3]Cutolo M, Vanhaecke A, et al. Autoimmun Rev. 2018;17(8):775-80.

Acknowledgements:

NIL.

Disclosure of Interests

None Declared.