Laser speckle contrast analysis predicts major vascular complications and mortality of patients with systemic sclerosis

Objectives. The aim of study was to evaluate peripheral blood perfusion and the proximal-distal gradient (PDG) of the hands as biomarkers of SSc major vascular complications (digital ulcers, pulmonary arterial hypertension, scleroderma renal crisis) and mortality by laser speckle contrast analysis.Methods. In this retrospective observational study, 176 SSc patients [158 female, median age 53 (51-57) years] and 142 healthy controls [115 female, median age 53 (48-55) years] were enrolled. Clinical data were collected at baseline and annually through 5 years of follow-up. Hand dorsum perfusion images were divided into three regions of interest (ROI): ROI1 included the second, third, and fourth fingers distal to the proximal interphalangeal finger joint; ROI2 included the area between the proximal interphalangeal finger joint and the metacarpophalangeal joint; ROI3 included the hand dorsum. PDG was identified when the perfusion mean difference between ROI1 and ROI2 was >30 perfusion units.Results. Median peripheral blood perfusion was significantly lower for SSc patients than healthy controls. PDG was present in 51.5% of SSc patients and in 98.6% of healthy controls. Using the final multivariate model, nailfold videocapillaroscopy (NVC) pattern [hazard ratio (HR) 0.065 (0.015-0.283), P <0.0001] and PDG [HR 0.376 (0.194-0.727), P <0.01] were found to be risk factors for major vascular complications. By multivariate analysis, age [HR 1.051 (1.014-1.088), P <0.01), NVC pattern [HR 0.001 (0.000-3.111), P >0.05], and PDG [HR 0.207 (0.073-0.589), P <0.01] were found to be risk factors for 5-year SSc mortality.Conclusion. PDG predicts major vascular complication and 5-year mortality of SSc patients.