Diagnosis

Diagnosis

Evidence suggests that PAD is greatly under diagnosed. Many patients do not report symptoms, or may not even have symptoms. People should be checked for peripheral artery disease if they have risk factors for heart disease, leg pain during walking, or ulcers on their legs.

Physical Examination

The doctor should perform a number of physical examinations to check for high blood pressure, heart abnormalities, blockage(s) in the artery in the neck, and abdominal aneurysms. The doctor should also examine the skin of the legs and feet for color changes, ulcers, infection, or injuries, and check the pulse of the arteries in the leg.

Doppler Ultrasound and Ankle-Brachial Index

Intermittent claudication caused by peripheral artery disease is typically diagnosed using a procedure called Doppler ultrasound and a calculation called the ankle-brachial index. This method is also proving to be a helpful way to diagnose PAD in patients without symptoms of intermittent claudication.

The procedure is done as follows:

• The doctor measures the systolic blood pressure of both arms while the patient is lying down. (The systolic pressure is "top" number in a blood pressure measurement. It is the force that blood exerts on the artery walls as the heart contracts to pump out the blood. For example, in a blood pressure reading of 120/80, 120 is the systolic number.)
• The doctor then puts blood pressure cuffs on four different locations on each leg. An ultrasound probe is passed over arteries in the foot. The signal emitted from the strongest artery is recorded as the cuffs are inflated and deflated. This is the ankle's systolic pressure.

The doctor divides the systolic pressure in the ankle by that in the arm. The result is called the ankle-brachial index (ABI), also called ankle-arm pressure index (API).

What the results mean:

• ABI over 0.90. This result often rules out PAD, but if the patient has specific risk factors for artery disease, the doctor may still suspect PAD. In such cases, the patient takes a treadmill test and another ABI measurement. If the API index drops, then the doctors makes a diagnosis of peripheral artery disease.
• ABI below 0.90. This is usually sufficient information to diagnose PAD. The lower the index the greater the risk for heart attack, stroke, or other serious circulatory or heart events. (In patients with diabetes, the doctor may perform additional tests, which may include ultrasound, pressure measurement in the first toe, or others that might confirm or dismiss a diagnosis of PAD.)
• ABI less than 0.50. These measurements are highly associated with impaired leg function.
• ABI less than 0.40. These measurements indicate very severe blockage in the leg arteries and a risk for gangrene.