Monitoring of peripheral blood flow in patients with systemic lupus erythematosus by using laser speckle contrast analysis

Abstract

Objective To noninvasively assess peripheral blood flow changes in patients with systemic lupus erythematosus (SLE) before and after treatments by using laser speckle contrast analysis (LSCA), to compare eripheral blood flow between SLE patients and healthy controls, and to evaluate effects of air temperature, age and gender on peripheral blood flow changes. Methods Clinical data on air temperature at the first visit (groups of ≥ 20 ℃ and < 20 ℃ ), age (groups of < 20, 20-< 40 and ≥ 40 years), gender, blood and urine routine test results, complement levels and immunologic test findings were collected from 47 patients with SLE. The patients' condition was evaluated by systemic lupus erythematosus disease activity index (SLEDAI), and Spearman's correlation analysis was carried out to assess its correlation with peripheral blood flow changes (expressed as changes in speckle flow index [△SFI]values) measured by LSCA. Peripheral blood flow was compared between the 47 patients and 30 healthy human controls. Results Compared with healthy controls, SLE patients showed significantly lower subungual SFI values (7.017 ± 0.356 vs. 9.765 ± 0.337, t = 5.182, P 0.05) compared with those at the baseline. Air temperature affected subungual blood flow significantly (t = 2.415, P 0.05). In addition, neither gender nor age had obvious effects on subungual or periungual blood flow. Conclusions Compared with healthy controls, peripheral blood flow significantly changed in patients with SLE, and was improved to a certain extent after treatment. Air temperature markedly affects subungual blood flow. LSCA may be a supplementary approach to more convenient and quantitative assessment of the severity of SLE. Key words: Lupus erythematosus, systemic; Blood flow velocity; Laser speckle contrast analysis