Venoarteriolar response to experimental venous hypertension in legs with chronic venous insufficiency and in healthy legs, measured using a double-wavelength laser Doppler technique

The venoarteriolar response (VAR) of the skin in legs caused by experimental venous hypertension was measured using a new, double-wavelength laser Doppler probe technique (543 nm and 780 nm). This enables the measurement of the laser Doppler flux in the superficial and deep layers of the skin simultaneously. The recordings were obtained from the leg with the patient in a recumbent position with a sphygmomanometer cuff around the thigh. The VAR was recorded at the cuff pressures of 30 mmHg and 60 mmHg. Ten patients with chronic venous insufficiency (CVI) and 20 control subjects with healthy legs were investigated. The VAR increased in relation to the increase of cuff pressure at both wavelengths. There were no significant differences in the VAR between the cuff pressures within or between the legs with CVI and healthy legs. The VAR measured at 780 nm was very significantly greater than the VAR measured at 543 nm in legs with CVI (p<0.005), as well as in healthy legs (p<0.001). The VAR depends both on the wavelength of the laser Doppler light used-and on the degree of venous hypertension. The VAR is not impaired in legs with CVI compared with healthy legs.