Pulse-generated run-off versus dependent Doppler ultrasonography for assessment of calf vessel patency

Pulse-generated run-off (PGR) is an established technique in the assessment of calf vessel patency. Dependent Doppler ultrasonography is proposed as a fast and simple alternative. Twenty-six limbs with severe ischaemia were evaluated by PGR, dependent Doppler examination and intra-arterial digital subtraction angiography (DSA). PGR was performed and scored as previously described. Dependent Doppler ultrasonography was performed after 5 min of foot dependency and scored as for PGR. Angiograms were scored by an independent radiologist, who awarded 2 for a vessel widely patent to the ankle, 1 for a diseased vessel crossing the ankle and 0 if no vessel was visualized. Of 78 calf vessels evaluated, 59 (76 per cent) appeared patent on PGR and dependent Doppler examination but only 33 (42 per cent) appeared patent to the ankle with intra-arterial DSA. There was very good agreement between PGR and dependent Doppler for detection of patent calf vessels (kappa = 0.93). Doppler signals were biphasic in six calf vessels on dependency and in 22 vessels with PGR. PGR and dependent Doppler ultrasonography detected 26 vessels communicating with the pedal arch compared with seven detected angiographically. There was good agreement between PGR and dependent Doppler examination for diagnosis of the most suitable vessel for distal anastomosis (kappa = 0.80). The wide availability and simplicity of dependent Doppler ultrasonography mean that no patient with a critically ischaemic limb should be denied reconstructive surgery on the basis of angiographic findings alone.