The easiest way to diagnose PAD is with the ankle-brachial index (ABI). This test involves putting blood pressure cuffs on the arms and on the ankles as shown in Figure 1. A handheld ultrasound device (“Doppler”) is used to listen to the blood flow and measure the blood pressure. The blood pressure at the ankle should be higher than the pressure at the arm; the ratio should be higher than 1.0. If the ankle pressure is lower than the arm pressure, then the arteries in the leg are probably blocked, and the diagnosis of PAD is made.
Several other tests are useful in the diagnosis and evaluation of PAD. In a more detailed blood pressure cuff test, the cuffs are placed at multiple areas on the legs to measure blood pressures and assess the blood flow. Another option is an arterial duplex scan, which uses ultrasound to determine the location of the blockages in the leg arteries and the severity of the blockages. When more information is needed to plan a procedure to restore blood flow to the leg, a vascular specialist may order a CTA (computed tomographic angiography) or MRA (magnetic resonance angiography). An example of a CTA is shown in Figure 2.
*Ratchford EV, Evans NS. Vascular disease patient information page: Peripheral artery disease. Vasc Med 2014; 19: 218–220. https://doi.org/10.1177/1358863X14534803. Used with permission from Sage Publications.