Influence of body position on venous reflux assessment: a duplex ultrasound study
Affiliations: 1. Department of Surgery, Ewha Womans University Medical Center, Ewha Womans University College of
Medicine, Seoul, Korea. 2. Thoracic and Cardiovascular Surgery, National Medical Center, Seoul, Korea
Venous reflux is commonly assessed using duplex ultrasound in the standing position. However, there is a lack of strong evidence to support this practice. This study aimed to evaluate the impact of body position on the detection of venous reflux.
Duplex ultrasound evaluations were conducted on 67 limbs from 36 patients (20 women, 16 men; mean age 56.4 years) to assess the great saphenous vein (GSV) and small saphenous vein (SSV) in both standing and supine positions. Venous diameters and the presence of reflux were recorded and compared across positions.
In the standing position, the mean diameters of the proximal thigh GSV, mid-thigh GSV, distal thigh GSV, below-knee GSV, and SSV were 6.0 mm, 5.5 mm, 4.7 mm, 4.5 mm, and 3.9 mm, respectively. In the supine position, these measurements were 5.6 mm, 4.5 mm, 4.4 mm, 3.9 mm, and 3.2 mm (P=0.080, P0.01, P=0.005, P<0.001, and P=0.007, respectively). Venous reflux in the deep vein system was detected in 11 limbs (16.4%) in the supine position and in 9 limbs (13.4%) in the standing position. The study also found 3 false-positive and 2 false-negative results in the deep vein system when assessing in the supine position. Additionally, 9 false-negative results were identified in the GSV, and 3 in the SSV in the supine position.
The findings suggest that venous reflux assessment using duplex ultrasound in the supine position is less reliable due to a higher incidence of false positives and negatives, as well as smaller superficial vein diameters.
