Evaluation of duplex ultrasonography versus other investigations in the diagnosis of ‘venous aetiology’ in patients with leg ulcers

Abstract Background The aim was to compare duplex imaging, venography, foot volumetry and air plethysmography in patients with healed leg ulcers considered to be caused by venous disease to discover whether duplex scanning alone could confirm a venous aetiology. The importance of isolated reflux in a segment of the deep system below a competent valve was assessed. Methods A total of 125 patients with 153 healed leg ulcers was examined. An Acuson (Mountain View, California, USA) scanner was used to detect reflux lasting for more than 0·5 s in the deep, superficial and calf perforating veins; the findings were compared with those obtained with ascending venography, foot volumetry and air plethysmography. Results Thirteen legs showed no reflux on duplex imaging, but ten of these had abnormal foot volumetry and 12 had abnormal plethysmography. Venography showed post-thrombotic change in 26 legs, but there was evidence of deep venous scarring in only six on duplex ultrasonography. Eight of 75 legs with a normal venogram had ‘complete’ (thigh-to-calf) deep reflux on duplex imaging. Forty-five legs showed segmental deep reflux on duplex imaging, of which 29 had associated perforating vein incompetence. Mean half-refilling times on foot volumetry were 8·46 s for femoral and 5·84 s for popliteal reflux, compared with 3·84 s in the 33 patients who had thigh-to-calf reflux (P < 0·05). Conclusion Absence of reflux in all venous segments on duplex imaging does not exclude a venous aetiology for ulceration. Segmental femoral and popliteal incompetence on duplex imaging is usually associated with other sites of valvular incompetence, but depresses calf function less than thigh-to-calf reflux.