Ultrasound classification of finger pulp blood flow in patients with systemic sclerosis: A pilot study.

OBJECTIVES To define a semi-quantitative classification of FPBF and to evaluate whether this classification could be used to assess FPBF in healthy controls and in SSc patients. METHODS 30 controls and 86 SSc patients were consecutively included. A classification of FPBF including 5 grades (from grade 0 (No signal) to 4 (signal detected on the entire finger pulp, including the sub-epidermal vascular network) was evaluated. This classification was explored in basal conditions and after hand baths in hot and cold water in controls. Its relevance was also assessed at room temperature in SSc patients. RESULTS In controls, PDUS FPBF was improved after hot challenge (p=0.024), whereas cold challenge decreased FPBF (p=0.001). FPBF correlated with the vasodilation status assessed by the resistivity index of radial arteries (R=-0.50, P=0.0049). Grade 0 was more frequent in SSc patients than in controls (22.1% versus 3.3% (p<0.05)). In SSc patients, Grade 0 was associated with severity markers of the digital vasculopathy such as digital ulcers (DU) (current or past) (p<0.05) or ulnar artery occlusion (p<0.05). On the contrary DU were less frequent in patients with Grade 4 (p<0.05). A pathological threshold of less than 2 (grade 0 or 1) was significantly associated with DU (OR=6.67, IC95% (2.31-19.21), p<0.0001). CONCLUSIONS PDUS allowed a semi-quantitative evaluation of FBPF in SSc and controls. Further studies are warranted to validate these results in independent SSc populations and to compare PDUS to existing tools assessing digital blood flow.