Laser Doppler flowmeter and standardized thermal test in normals and Raynaud's phenomenon

The diagnosis of Raynaud's phenomenon alone requires clinical investigations. To determine the stage of the disease, its etiology and pathophysiology, it seems desirable to perform noninvasive tests. Conclusions regarding control o the skin or muscle components of hand blood flow rely on evidence from separate measurements of skin or muscle blood flow. We described a standardized thermal provocation test, then respiratory maneuvers and pharmacological trials, to stimulate the microcirculatory control. The total cutaneous blood flow was continuously registered using a laser Doppler flowmeter. We conducted a prospective study on 100 subjects: 21 normal, 22 primary Raynaud's phenomenon (PRP), 26 secondary (SRP), 31 various microcirculatory diseases. The basal blood flow was lower in cases of severe SRP and acrocyanosis. In comparison with normals, RP cases present a less noticeable reaction to cold. Mild SRPs are more sensitive to cold and do not recover during warming up. Severe RPs are less sensitive to cold as they have a lower basal blood flow. Acrocyanosis cases are not sensitive to thermal variations. Post ischemic reactive hyperemia leads to a constant peak flow. Pharmacological assays were performed (nitroglycerine, Nifedipine) during permanent control of skin and muscle blood flow. Laser Doppler and provocation tests have no etiologic value in a Raynaud's phenomenon investigation; this methodology tries to elucidate the pathophysiology, the prognosis and the therapy of Raynaud's phenomenon.