Microvascular responses following digital thermal hyperaemia and iontophoresis measured by laser Doppler imaging in idiopathic inflammatory myopathy

• Published in: Rheumatology (Oxford, England) Vol. 46; no. 9; pp. 1483 - 1486
• Main Authors: Gunawardena, H., Harris, N. D., Carmichael, C., McHugh, N. J.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.09.2007; Oxford Publishing Limited (England)
• Subjects: Aged; Biological and medical sciences; Cardiovascular system; Dermatomyositis - physiopathology; Diseases of striated muscles. Neuromuscular diseases; Endothelial function; Endothelium, Vascular - physiopathology; Female; Fingers - blood supply; Humans; Hyperemia - physiopathology; Investigative techniques, diagnostic techniques (general aspects); Iontophoresis; Laser Doppler imaging; Laser-Doppler Flowmetry - methods; Male; Medical sciences; Microcirculation; Microvascular; Middle Aged; Myositis; Myositis - physiopathology; Neurology; Polymyositis - physiopathology; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Ultrasonic investigative techniques; Vasodilation; Myositis; Microvascular; Laser Doppler imaging; Endothelial function; Doppler ultrasound study; Skin disease; Vasodilator agent; Autoimmune disease; Iontophoresis; Microcirculation; Systemic disease; Sonography; Human; Immunopathology; Connective tissue disease; Dermatomyositis; Idiopathic; Sodium nitroprusside; Striated muscle disease; Polymyositis; Laser; Neurotransmitter; Antihypertensive agent; Acetylcholine; Myopathy
• ISSN: 1462-0324; 1462-0332
• DOI: 10.1093/rheumatology/kem175

Objective. To measure microvascular function using laser Doppler imaging following digital hyperaemia and iontophoresis of vasoactive substances in patients with idiopathic inflammatory myopathy (IIM). Methods. Fifteen patients with IIM including eight patients with dermatomyositis (DM) and seven patients with polymyositis (PM) were studied. Fifteen age-matched normal controls were also recruited. Scanning red laser Doppler imaging (LDI) was performed after resting the subject in a temperature controlled room at 23°C for 20 min. An initial LDI scan was performed to assess baseline blood flow. Digital microvascular responses were quantified following a maximum hyperaemic response (MHR) and iontophoresis with endothelial dependent acetylcholine (Ach) and endothelial independent sodium nitroprusside (SNP). Maximum vasodilation following iontophoresis was expressed as a percentage of the MHR. Results. All subjects were age matched, and the duration of disease was similar between the IIM patients. There was no significant difference in baseline blood flow when comparing the three study groups. There was no significant difference in MHR or SNP/MHR when comparing DM or PM with controls. However, Ach/MHR was significantly lower in both the DM and PM group compared with controls (both P < 0.01). There was no significant difference in any of the microvascular responses when comparing patients with DM directly with PM. Conclusion. This is the first study to evaluate microvascular responses using LDI in patients with IIM. We have demonstrated that patients with DM have abnormal endothelial dependent mediated vasodilation and the same abnormality is present in patients with PM.