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Venous haemodynamic effects of anti-thromboembolism stockings

Objective: The aim of this study was to assess the haemodynamic changes in the deep veins of 13 volunteers, following application of 13 made-to-measure graduated compression stockings all designed to exert different compression gradients along the limb. Methods: The compression gradients were designed to apply pressures from 12–22 mmHg at the ankle to 9–20 mmHg at the calf and 5–10 mmHg at the thigh. These had been laboratory tested by the Hosiery Pressure Tester Mark II (HATRA). A medical stocking tester (MST) was subsequently used to measure the actual pressure measurements on the volunteers. A duplex scanner was used to measure the venous velocity in the deep veins at predetermined sites. Results: The application of all the stockings increased the mean velocity in the popliteal vein by 38.7% (confidence interval [CI] 8–64%, P<0.01) but produced only a slight statistically insignificant increase in velocity in the femoral vein. No particular stocking profile gave significantly better results. A good correlation was found between the MST and HATRA tester measurements of the stocking pressures at the ankle and calf, but the MST method usually recorded higher pressures for the thigh measurements. Conclusions: All profiles of graduated stockings appear to increase the velocity of blood in the deep veins above the knee, but only four pressure profiles (average 16.5, 14 and 6 mmHg) produced significant increases in velocity. There was no evidence to suggest that any one specific compression profile was superior to others at increasing the venous velocity in the popliteal vein.