Microvascular Response in Patients with Complex Regional Pain Syndrome as Measured by Laser Doppler Imaging.
Our aim was to investigate the hypothesis that microvascular dysfunction occurs in patients with CRPS. Specifically, whether there were functional differences in either deeper cutaneous blood vessels or more superficial nutritive vessels between the affected and unaffected limb in patients with CRPS, and between CRPS patients and healthy control subjects.



Twenty-two patients with CRPS (five male; mean age 45 years; eight upper limb involvement, 14 lower limb) and 23 healthy control subjects (one male; 43 years) were recruited. Microvascular flow at affected and unaffected contralateral sites was measured, following local heating, using laser Doppler imaging (red/green wavelengths). Corresponding sites were imaged in healthy controls. Maximum flux level and area under the curve (first 20 scans, AUC20) were measured.



Vasodilator responses to heat were similar in affected and unaffected limbs, and in healthy controls. For example, median (IQR) "red" AUC20 in CRPS was 138.6 (120.0-152.9)% change from baseline in affected limb and 135.0 (120.7-166.8)% in unaffected limb, and (in healthy controls) 133.1 (117.2-145.9)% and 139.1% (126.0-162.1) in limb 1 and 2.



We found no impairment of vasodilation in cutaneous microvessels in CRPS. The vasomotor changes in CRPS may relate to larger vessel dysfunction.
The Kellgren Centre for Rheumatology, Manchester Royal Infirmary, Manchester, UK.
Rachel
R
Gorodkin
Institute of Inflammation and Repair, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Trust, The University of Manchester, Salford, UK.|NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
Ariane L
0000-0003-4941-7926
AL
Herrick
Institute of Inflammation and Repair, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Trust, The University of Manchester, Salford, UK.|Photon Science Institute, University of Manchester, Manchester, UK.
Andrea K
0000-0001-9244-2882
AK
Murray
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D020918:Complex Regional Pain Syndromes / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000379:methods*; D008297:Male; D055806:Microvessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008875:Middle Aged; D012867:Skin / Q000098:blood supply; D014664:Vasodilation / Q000502:physiology; D055815:Young Adult
blood flow; complex regional pain syndrome; laser Doppler imaging