How Is Peripheral Arterial Disease Diagnosed?

Peripheral arterial disease (PAD) is diagnosed based on general medical and family history, history of leg or heart problems, personal risk factors, a physical exam, and test results. An accurate diagnosis is critical, because people with PAD face a six to seven times higher risk of heart disease or stroke than the rest of the population. PAD is often diagnosed after symptoms are reported. If you have PAD, your doctor also may want to look for signs of coronary artery disease (CAD).

Specialists Involved

Mild PAD may be managed by a primary care doctor, internist, or general practitioner. For more advanced PAD, a vascular specialist (a doctor who specializes in treating blood vessel problems) may be involved. A cardiologist (a doctor who specializes in heart diseases) also may be involved in the care of patients with PAD.

Medical and Family History

Medical and family history is important in diagnosing PAD. Your doctor may:

• Ask about your family history of cardiovascular disease
• Review your medical history, including high blood pressure or diabetes
• Ask about any symptoms, including any symptoms that occur when walking or exercising
• Ask if you are currently or used to be a smoker
• Ask if you have any symptoms in the legs when sitting, standing, walking, or climbing
• Review your diet
• Review your current medicines

Physical Exam

The physical exam may involve:

• Checking blood flow in your leg or foot to see if the pulse is either weak or absent.
• Checking pulses in your leg arteries for an abnormal whooshing sound called a bruit (broo-E). A bruit can be heard with a stethoscope and may be a warning of a narrow or blocked section of an artery.
• Checking for poor wound healing.
• Comparing blood pressure between your limbs to see if blood pressure is lower in the affected limb.
• Checking hair, skin, and nails for any changes that may indicate PAD.

Diagnostic Tests and Procedures

A simple test called an ankle-brachial index (ABI) can be used to diagnose PAD. The ABI compares blood pressure in the ankle with blood pressure in the arm to see how well blood is flowing. A normal ABI is 1.0 or greater (with a range of 0.90 to 1.30). The test takes about 10–15 minutes to measure both arms and both ankles. It can help the doctor find out if PAD is affecting the legs, but it will not identify which blood vessels are blocked. The ABI can be performed yearly if necessary to see if the disease is getting worse.

The illustration shows the ankle-brachial index (ABI) test. The ABI gives the ratio of the systolic blood pressure in the ankle to the systolic blood pressure in the brachial artery of the arm.

A Doppler ultrasound is a test that uses sound waves to tell whether a blood vessel is open or blocked. This test uses a blood pressure cuff and special device to measure blood flow in the veins and arteries in the arms and legs. The Doppler ultrasound can help to determine the level and degree of PAD.

A treadmill test will provide more information on the severity of the symptoms and the level of exercise that provokes symptoms. For this test, you will walk on a treadmill, which will help identify any difficulties that you may have during normal walking.

A magnetic resonance angiogram (MRA) uses radio wave energy to take pictures of blood vessels inside the body. MRA is a type of magnetic resonance imaging (MRI) scan. An MRA can detect problems that may cause reduced blood flow in the blood vessels. It can determine the location and degree of blockage. A patient with a pacemaker, prosthetic joint, stent, surgical clips, mechanical heart valve, or other metallic devices in his or her body might not be eligible for an MRA depending on the type of metallic device.

An arteriogram is a "road map" of the arteries used to pinpoint the exact location of the blockage in a limb. An x ray is taken after injecting dye through a needle or catheter into an artery. When the dye is injected, the patient may feel mildly flushed. The pictures from the x ray can determine the location, type, and extent of the blockage. Some hospitals are using a newer method that uses tiny ultrasound cameras to take pictures inside the blood vessel.

Blood tests may be done to check the patient's blood sugar level to screen for diabetes. Blood tests also may be used to check the patient's cholesterol levels.