Predictive value of laser speckle contrast analysis in systemic sclerosis. A systematic review and pilot study.

Objectives: To assess whether tools to functionally examine the microcirculation, such as laser speckle contrast analysis (LASCA), are predictive of ischaemic digital trophic lesions ([i]DTL) in patients with systemic sclerosis (SSc).

Methods: First, a systematic review (according to PRISMA) was conducted to identify studies describing a link between LASCA and SSc-related (i)DTL. In the additional pilot study, consecutive SSc patients underwent clinical and LASCA examinations (to assess the peripheral blood perfusion [PBP] of both hands) at enrolment. For one year, a monthly telephone survey was conducted to investigate (i)DTL occurrence. Logistic regression and ROC analysis were performed.

Results: None of the three manuscripts retained through the systematic review examined the predictive value of LASCA for future (i)DTL. In our pilot study, 7/106 (6.6%) SSc patients developed at least one iDTL during follow-up, with PBP not found to be predictive (OR = 0.995, p = .418; ROC-AUC = 0.597). Post hoc, when only patients not taking vasodilators were analysed (n = 57), all three who developed iDTL had an average PBP ≤ 70 PU, while only 9/54 (16.7%) patients without iDTL occurrence had such values.

Conclusion: A predictive role of LASCA for (i)DTL has not yet been described in the literature and could also not be attested by our additional pilot study, due to a lower-than-expected iDTL incidence in our day-to-day SSc population in which patients were allowed to continue their vasodilator medication. However, the promising observations in the subgroup of vasodilator-naïve patients encourage further investigation of this potential added value of LASCA.