[Indications for, technique and interpretation of arterial Doppler sonography from the vascular surgeon's viewpoint]

Doppler sonography is one of the most important diagnostic tools for angiologists and vascular surgeons and also for general practitioners with an interest in vascular disease. It can be carried out easily and at low cost and, at the same time, provides reproducible, quantitative data on which further diagnostic and therapeutic decisions can be based. First, systolic arterial pressures in the anterior and posterior tibial and in the peroneal arteries are measured, with the Doppler probe placed at ankle level. A cuff is wrapped around the lower leg and inflated until the Doppler signal disappears. The highest value measured in each leg is termed ankle pressure. Division of the latter by systolic brachial pressure results in the so-called ankle-brachial index or "ABI". Ankle pressure and ABI correlate well with clinical findings. In normal individuals it is greater than 1. In claudication it ranges between 0.3 and 0.9, in patients with resting pain between 0.1 and 0.5 and with ischemic tissue loss between 0.0 and 0.2. After angioplastic or surgical revascularization procedures, a fall of the ABI by 0.15 or more is an indication of relevant hemodynamic deterioration and, therefore, calls for further investigation by arteriography or color duplex sonography.