Prospective study of duplex scanning for venous reflux: comparison of Valsalva and pneumatic cuff techniques in the reverse Trendelenburg and standing positions.

Abstract

To achieve uniform testing of venous reflux between institutions, comparable methods of testing by duplex scanning are desired. This study directly examines differences of testing by two techniques, Valsalva and rapid cuff deflation, performed in two positions: 15-degree reverse Trendelenburg (RT-15) and standing. Duplex examination of 22 extremities in 19 patients with moderate to severe, class 2 and 3 chronic venous insufficiency symptoms were compared with duplex scanning of 21 limbs in 11 normal, healthy volunteers. Duration of retrograde flow and peak velocity were measured in 247 venous segments. All extremities were studied in four ways: RT-15 Valsalva, standing Valsalva, RT-15 cuff, and standing cuff. Reflux was defined as duration of retrograde flow or reflux time greater than 0.5 seconds. Six venous segments were examined: common femoral, superficial femoral, deep femoral, and greater saphenous in the upper thigh, popliteal, and posterior tibial (at the ankle). The results of testing the Valsalva technique and the cuff in both the RT-15 and standing non-weight bearing positions indicate that the Valsalva method is best performed in the RT-15 position as opposed to standing, whereas the cuff technique is more effective in the standing position. In symptomatic limbs, the RT-15 Valsalva method showed similar proportion of reflux in the upper thigh when compared with the standing cuff method: common femoral (90% vs 67%), superficial femoral (81% vs 71%), greater saphenous (88% vs 59%), and deep femoral veins (30% vs 15%). In the popliteal vein the standing cuff test showed similar proportion of reflux (77%) as compared with the RT-15 Valsalva test (68%); however, a case-by-case analysis identified a large amount of variability between techniques, and inconsistencies could not be used to identify one technique as better than the other. Examination of the posterior tibial veins by all methods produced inconsistencies and a low yield of reflux in symptomatic limbs. In the common femoral vein, RT-15 Valsalva testing produced reflux times of up to 1.5 seconds in normal limbs, and represented "physiologic reflux." There was no recognizable effect of iliac vein valves on testing distal venous segments by Valsalva maneuver. Reflux in the upper thigh veins--common femoral, superficial femoral, deep femoral, and greater saphenous-is similarly demonstrated in both normal and symptomatic states by cuff deflation and RT-15 Valsalva techniques. In the popliteal vein, discrepancies between these two techniques are identified in patients with chronic venous insufficiency, and tibial vein reflux is not well demonstrated by either technique. Further investigation is needed to determine ideal techniques for identifying popliteal and tibial vein reflux.