REFINEMENTS IN THE ULTRASONIC-DETECTION OF POPLITEAL VEIN REFLUX

Color-flow and duplex ultrasonography were used to determine the optimal method for documenting venous valvular reflux. Popliteal veins were examined in 10 normal limbs and 11 limbs with clinical evidence of chronic venous insufficiency (CVI). Peak reflux velocity (spectral) and duration of reflux (spectral and color) were measured with the patient in supine and standing positions, with manual and pneumatic compression applied sequentially to thigh and calf. Manual and pneumatic compression produced equivalent reflux velocity and duration. In normal limbs peak reflux velocity was always less than 22 cm/sec, with a mean reverse flow duration of 0.3 sec +/- 0.03 (SEM). In limbs with CVI, reflux velocity varied widely among protocols. Reflux duration and velocity were greater in the supine position than in the standing position for both normal limbs and limbs with CVI (p < 0.04). Duration was significantly increased for thigh versus calf compression in normal limbs (p < 0.001) but decreased in limbs with CVI (p < 0.003). Methods that used thigh compression or supine position were less capable of discriminating normal limbs from limbs with CVI. Standing calf compression provided the greatest rates of sensitivity (91%), specificity (100%), and accuracy (95%). Compared with spectral Doppler scanning, color-flow ultrasonography produced a consistently shorter reflux duration (p < 0.001). In limbs with CVI with a mean spectral duration of 2.5 sec +/- 0.2 (SEM), mean color Doppler duration was 0.7 sec shorter. Our results demonstrate that popliteal vein incompetence is identified optimally by reflux duration after standing calf compression; adequate manual compression is sufficient to identify reflux; color-flow Doppler ultrasonography may underestimate reflux duration.