The effect of sympathetic blockade and cooling in Raynaud's phenomenon

Nineteen patients with Raynaud's phenomenon (12 suffering from generalized scleroderma [GS] and seven from primary Raynaud's phenomenon [PR] and seven cold-tolerant healthy women underwent a cooling challenge with combined body and finger cooling. Finger systolic blood pressure was measured at 30 and 15 degrees C, before and after nervous blockade at the finger-base with lidocain. Finger/arm blood pressure ratio (FBP/armBP) at 30 degrees C was significantly lower in GS as compared to controls and PR, and it did not change after nervous blockade in any group. FBP/armBP at 15 degrees C, decreased to zero in all patients with Raynaud's phenomenon and to median 0.67 in controls, prior to nervous blockade. After nervous blockade, in response to cooling, FBP/armBP at 15 degrees C decreased significantly and was comparable in all groups. We conclude that the sympathetic nervous system seems to play an important part in provoking Raynaud's phenomenon in PR and most GS.