The combination of laser Doppler perfusion imaging and photoplethysmography is useful in the characterization of scleroderma and primary Raynaud's phenomenon

Abstract

Objective: To investigate simultaneously skin perfusion and digital artery pulsatility of hands in patients with primary Raynaud's phenomenon (PRP) and systemic sclerosis (SSc).Methods: In 100 SSc patients, 92 PRP patients, and 80 healthy controls, perfusion and digital artery pulsatility of the hands were investigated by laser Doppler perfusion imaging (LDPI) and photoplethysmography (PPG), respectively.Results: Both the mean value of mean perfusion and the mean value of sphygmic wave amplitude were lower (p < 0.0001) in the PRP group than in the SSc group, and also in the SSc group compared with the healthy controls. A positive correlation (r = 0.95) was found between the mean value of mean perfusion and the mean value of sphygmic wave amplitude. A homogeneous perfusion distribution pattern was present in 95% of the healthy controls, 93% of the PRP patients, and 4% of the SSc patients. PPG shows a homogeneous pattern in 95% of the healthy controls, 93% of the PRP patients, and 28% of the SSc patients. LDPI and PPG showed a positive concordance (p < 0.05) in homogeneous pattern evaluation. In the SSc patients, no correlation (r = 0.38) was observed between the mean value of sphygmic wave amplitude and the mean value of mean perfusion of each finger.Conclusion: LDPI and PPG can provide useful information in distinguishing patients with PRP and SSc, although nailfold videocapillaroscopy (NVC) is the best method for analysing microvascular damage in rheumatic diseases.