Capillary blood cell velocity in periulcerous regions of the lower leg measured by laser Doppler anemometry.

Background: The capillary blood flow of the nailfold can be measured by means of modern non-invasive techniques like the videocapillary microscope in vivo. To quantify the capillary blood cell velocity, apart from the nailfold capillaries, we used a new technique, the so-called laser Doppler anemometry (LDA).
Objective: The present study investigated how far laser Doppler fluxmetry (LDF), transcutaneous partial pressure of oxygen (tcpO2), and LDA are capable of quantifying differences of cutaneous microcirculation between patients with leg ulcera and a healthy control group. The effects of intravenous prostaglandin E1 and pentoxifylline were also investigated.
Patients and Methods: Ten patients with venous leg ulcers and 10 patients with mixed venous/arterial ulcers were investigated with LDF, tcpO2, and LDA before and after injection of prostaglandin E1 and pentoxifylline. We measured the resting capillary blood cell velocity (rCBV), the maximum hyperemia, and the time to peak capillary blood cell velocity (tpCBV) during hyperemia after 4 min of suprasystolic occlusion and compared them with the results of a contol group of 20 patients.
Results: Laser Doppler flow was increased in all patients during resting period, whereas the tcpO2 was significantly decreased. LDF did not show an extension of tpCBV during reactive hyperemia after suprasystolic occlusion compared to the control group (73.6+/-31.1 vs. 164.1+/-52.5 s, P=0.003). TcpO2 revealed significantly decreased tpCBV in patients with venous and mixed venous/arterial ulcers (90.1+/-61.7 vs. 162.7+/-65.5 s, P< or =0.0001). LDA showed no significant differences between patients and control group (P>0.8). After application of prostaglandin E1, LDA revealed a significant increase of erythrocyte velocity (0.5+/-0.18 to 0.74+/-0.28 mm/s [P=0,01]), whereas pentoxifylline had no significant effect. Capillary density increased significantly after application of prostaglandin E1 (5,1+/-2.7/mm2 to 8.9+/-3/mm2 [P=0.001]) and pentoxifylline (5.3+/- 1.8/mm2 to 8+/-2.1/mm2 [P=0.006]).
Conclusion: The LDA is an important additional investigation tool for cutaneous microcirculation.