Predictive value of bruits and Doppler pressure measurements in detecting lower limb arterial stenosis

The value of bruits and Doppler ankle pressure measurements as indicators of arterial stenosis was studied in 50 patients with symptoms of lower limb ischaemia. The iliac and femoropopliteal arteries were examined for bruits, ankle systolic pressures were measured before and after an exercise stress test and the results were compared to the findings of digital subtraction angiography (DSA). Patients with occlusive lesions in the iliac and femoropopliteal arteries were not analysed. This left a group of 37 symptomatic legs in which the popliteal pulse was palpable. In this sub-group, DSA demonstrated 25 limbs with arterial stenoses and 12 limbs without evidence of a stenosis. The presence of a bruit had a sensitivity of 80%, a specificity of 75%, a positive predictive value of 87%, a negative predictive value of 64% and an accuracy of 78%. A fall in Doppler ankle pressure of > or = 20 mmHg had a sensitivity of 92%, a specificity of 75%, a positive predictive value of 88%, a negative predictive value of 82% and an accuracy of 86%. When used selectively, clinical examination for bruits has good accuracy and may be of clinical value in the early identification of patients who are suitable for percutaneous transluminal angioplasty.