The assessment of skin blood flow in peripheral vascular disease by laser Doppler velocimetry

The helium-neon laser Doppler (LD) is designed to measure skin blood flow velocity (SBFV). Flow velocity and pulse wave amplitude are expressed in millivolts (mv) relative to a zero-flow reference. The authors have reviewed their initial experience in ten persons (20 limbs) without peripheral vascular disease (PVD, group I) and nine patients (12 limbs) with severe PVD (group II). The finger, palm, great toe, and forehead had a significantly (P < 0.05) greater flow velocity than the plantar and dorsal foot, distal and proximal leg, thigh, chest, arm, and forearm. Baseline and hyperemic SBFV, measured at the great toe, were compared in groups I and II. In group I, the baseline SBFV (mv, mean ± standard error of the mean (SEM) in the great toe was 197 ± 38 compared with 67 ± 12 in group-II patients (P < 0.05). The pulse wave amplitude (mv, mean ± SEM) was 77 ± 14 in group I and 5.4 ± 1.1 in group II (P < 0.05). The time to maximal hyperemic response (seconds, mean ± SEM) in group I was 18 ± 1.5 compared with 150 ± 14 in group II (P < 0.05). LD is a sensitive indicator of changes in SBFV, allowing differentiation between normal persons and patients with PVD. The LD tracing in patients with PVD is characterized by a baseline SBFV that is significantly less than normal and also by the attenuation or absence of pulse waves. The diagnostic accuracy is enhanced by the use of reactive hyperemia.