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

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).

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.

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.

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.