Laser-Doppler velocimetry and photoplethysmography in the diagnosis of abnormal venous reflux.

Laser-Doppler Velocimetry (LDV) is useful in measurement of relative tissue blood flow. We have found a change in both the variability of the LDV waveform and its absolute level when measured in the supine and dependent limb, in patients with venous reflux. These changes correlated with simultaneous photo-plethysmographic (PPG) assessment of venous reflux and were more pronounced in patients with leg ulcers. These changes were also reduced by compression bandaging.