Noninvasive studies for the peripheral artery disease patient

Numerous noninvasive diagnostic tests can be performed to detect peripheral arterial disease (PAD), and these can be separated into direct and indirect examinations. The test chosen is determined on the basis of both the presenting symptoms of the patient and the needs of the health care provider. A simple pressure measurement is often used to screen an asymptomatic patient for PAD, and a more specific and detailed test, such as ultrasound, is required to determine disease within a stent or bypass. Indirect testing types include the measurement of systolic pressures within a limb or digit and acquisition of waveforms. The combination of quantitative data from pressures and qualitative data from waveforms is used to provide an accurate assessment of global perfusion in a limb. Direct noninvasive testing is performed with duplex ultrasound techniques. With ultrasound, specific anatomic features can be visualized directly. Spectral waveforms obtained with duplex ultrasound can be characterized and velocities can be measured. Criteria exist to categorize disease on the basis of velocities and velocity ratios and by using this objective hemodynamic data, progression of disease may be followed. The focus of this review was to describe the various types of direct and indirect arterial noninvasive testing for detection and management of PAD. The advantages and disadvantages of each will be explained, as well as common applications for these tests. Direct, indirect, or a combination of direct and indirect testing may be required to accurately determine the presence, level, and severity of PAD.