Ankle-Brachial Index Use in Patients with Diabetes

Advances in Skin & Wound Care, Apr 2004

Peripheral arterial disease (PAD) in the lower extremities signals widespread arterial disease and a high risk of stroke, myocardial infarction, and death. Because many patients with diabetes also have PAD, the American Diabetes Association now recommends testing for PAD in any patient with diabetes who is over age 50.' Patients with diabetes who are younger than age 50 should be screened for PAD if they have risk factors for PAD, such as smoking, hypertension, hyperlipidemia, or diabetes for more than 10 years.1

The recommended test is the ankle-brachial index (ABI), which measures the ratio of systolic blood pressure in the ankle and the arm. The ABI can be used to detect decreased blood pressure distal to sites of artery narrowing. If the results are normal, the ADA recommends that patients be rechecked every 5 years.1

However, the ABI is not a foolproof way to assess patients with diabetes. These patients may have falsely elevated ABIs because their disease process causes calcification that decreases compressibility of the arteries. Therefore, clinicians must pay close attention to the patient's physical presentation. A patient who presents with cold and/or hairless lower extremities, for example, may have PAD regardless of a normal ABI. If the physical examination warrants, the patient may need a toe brachial pressure index to determine arterial perfusion in the feet and toes.

When measuring the ABl, use a handheld, 5 to 10 MHz Doppler ultrasound device1 and follow the steps shown in the photographs on page 106 to detect the brachial and ankle pulses.

Reference

1. American Diabetes Association. Peripheral arterial disease in people with diabetes. Diabetes Care 2003;26:3333-41