INFLUENCE OF LOCAL FINGER COOLING ON LASER-DOPPLER FLUX AND NAILFOLD CAPILLARY BLOOD-FLOW VELOCITY IN NORMAL SUBJECTS AND IN PATIENTS WITH RAYNAUDS-PHENOMENON

We examined the influence of local cooling (- 15°C, 60 sec) on blood flow velocity in nailfold capillaries and on laser Doppler flux (LDF) at the fingertip in 12 patients with primary Raynaud's phenomenon (PRP) and 13 patients with secondary Raynaud's (SRP) in comparison with 10 health controls. Skin temperature at the pulp of the finger decreased significantly during local cooling in RP but not in controls. LDF before cooling was comparable between patients and controls and dropped significantly under cooling. Flux motions at the fingertip were present in all individuals with 7.9-9.1 cycles/min. Flux motions persisted throughout the cooling test and faded away in 5 patients (1 PRP, 4 SRP) with cooling. Frequency of LDF motions was little influenced by a change in skin temperature. The amplitudes were dampened in relation to the drop in LDF level during local cooling in patients with RP. We conclude that LDF does respond to local cooling of the fingertip by significant decrease of perfusion but not with regard to flux motions. The wide overlap of the single values does not allow as good a separation of patients with RP from controls as capillary microscopy. © 1993 Academic Press. All rights reserved.