DIGITAL BLOOD-FLOW RESPONSE TO BODY WARMING, COOLING, AND REWARMING IN PATIENTS WITH RAYNAUDS-PHENOMENON

Although the diagnosis of Raynaud's phenomenon (RP) is usually made ea sily from a careful history, the assessment of RP severity is difficul t, for the vasopastic attacks are not easily induced under experimenta l conditions. In this study, the laser Doppler flowmetry (LDF) techniq ue was used to quantify digital blood flow, which was standardized by body cooling and warming in patients with RP. Twenty-one healthy subje cts and 56 RP patients were studied: 7 had primary RP, 22 had suspecte d secondary Raynaud's syndrome (susp RS), and 27 had systemic sclerosi s (SSc)-associated secondary Raynaud's syndrome (SSc RS). The inherent variability in the acral cutaneous circulation was minimized by whole -body warming and cooling. Digital blood flow values at environmental temperatures of 40 degrees C, 12 degrees C, and after rewarming, to 40 degrees C were recorded, as was the time taken for blood flow to reac h 25%, 50%, and 75% of the full effects of whole-body cooling and rewa rming. Patients with primary RP and susp RS had normal blood flow valu es at ambient temperatures of 40 degrees C, 12 degrees C, and after re warming to 40 degrees C when compared with controls, but they had sign ificantly faster vasoconstrictor responses to whole-body cooling, sugg esting a heightened sympathetic activity. Additionally, they had slowe r vasodilator responses with longer 25%(max) response time to whole-bo dy rewarming. Patients with SSc RS had significantly lower blood flow values at 40 degrees C after initial warming and following subsequent rewarming, and despite a normal vasoconstrictor response to cooling, i t took longer for them to vasodilate during rewarming, suggesting that poor digital blood flow in these patients may be more related to digi tal vasculature abnormalities and not an increase in sympathetic activ ity. In conclusion, our assessment technique can be used to quantify d igital blood flow in patients with RP and may be potentially useful in the investigation of the etiologic role of the sympathetic nervous sy stem in RP.