Noninvasive evaluation of chronic venous insufficiency. Use of foot mercury strain-gauge plethysmography.

Twenty-seven patients (40 extremities) with chronic venous insufficiency and 30 controls (60 extremities) were studied using noninvasive measurements of foot volume (foot mercury strain-gauge plethysmography [FMSGP]). Tests were performed with exercise (sitting) and with elevation (Trendelenburg), with and without tourniquets, to evaluate muscle pump efficiency and valvular competence. Empiric venous sufficiency indexes were calculated for exercise and for Trendelenburg's test. Test results were compared with invasive ambulatory venous pressure (AVP) data (13) and with ascending and retrograde venography (25). Distinctive plethysmographic patterns revealed the insufficiency was saphenous (four), calf perforators (14), saphenous plus perforators (seven), and deep venous (15), including occlusion (four). Correlation with AVP and venography was good but FMSGP was more discriminating, providing precise anatomical information, better reproducibility, and distinguishing poor muscle pump function from regurgitation. Patients accept FMSGP well. Repeated postoperative data are readily obtained for evaluation of surgical procedures.