Digital laser doppler flowmetry may discriminate "limited" from "diffuse" systemic sclerosis

Abstract OBJECTIVES: To investigate skin blood flux and microvascular functional changes by laser Doppler flowmetry (LD) in patients with systemic sclerosis (SSc) at baseline and following dynamic stimulations. METHODS: Skin blood flux of the dorsal hands was recorded by LD at baseline and after the cold test and the post-occlusive hyperemia test in 59 SSc patients (49 limited cutaneous, 10 diffuse cutaneous). Twenty-five patients with primary Raynaud's phenomenon (PRP), and 31 healthy donors (HD) were studied as controls. RESULTS: After the cold test, SSc patients had a significantly higher reduction of the blood flux (-38.4%+/-28) than PRP (-21.1%+/-37) and HD (-22.1%+/-23) subjects (p<0.05). Within the SSc group, the cold test flux was significantly reduced in limited-SSc (-399%+/-28, p<0.05), but not in diffuse-SSc (-31.2%+/-29), whereas, the time needed to recover the basal flux after the occlusive/ischemic test was significantly longer in diffuse-SSc (18.8s+/-21)than in limited-SSc (4.5s+/-4, p<0.01) or HD (2.2s+/-2, p<0.01) or PRP (0.4s+/-0.7, p<0.01). CONCLUSIONS: These data clearly indicate an impairment of vascular tone regulatory mechanisms in SSc and suggest that a peculiar pathogenic mechanism may be involved in different SSc subset. Nevertheless, it has clear that PRP and SSc-associated RP have a distinct pattern at LD evaluation, and monitoring patients with PRP could be helpful to understand whether a change in the LD pattern might predict the development of SSc.