Laser-Doppler measurement of digital blood flow regulation in normals and in patients with Raynaud's phenomenon.

Finger blood flow was measured continuously by a laser-Doppler flowmeter in normal subjects and in patients suffering from primary or secondary Raynaud's phenomenon. In normals, skin areas with and without arteriovenous anastomoses could be differentiated. Blood flow in areas with shunt vessels decreased after a deep breath but not during venous stasis or the Valsalva maneuvre, while in other skin areas a decrease in blood flow was observed after all three maneuvres, suggesting a dual innervation of nutritional and shunt vessels. In patients with Raynaud's phenomenon (scleroderma) fingertip blood flow reacted in the same way as normal skin without shunt vessels. During direct and indirect cooling, finger blood flow in patients with secondary Raynaud's phenomenon reacted with the same relative reduction as normals but resting blood flow in the patients was significantly decreased and the rewarming period was greatly prolonged. In patients with primary Raynaud's phenomenon an even more prolonged decrease in blood flow was observed after direct or indirect cooling. Defective function of arteriovenous anastomoses is proposed as an explanation of the deviations from normal. A pathophysiological classification of Raynaud's phenomenon may be possible on the basis of the function tests described.