Peripheral Artery Disease Diagnosis
Your healthcare provider will diagnose peripheral artery disease (PAD) based on your medical and family history, a physical exam, and the results from tests and procedures.
Medical history and physical exam
To help diagnose PAD, your provider will want to learn about your symptoms, risk factors, personal health history, and family health history. This discussion may include questions about the following:
- Other medical conditions, including diabetes, heart disease, and chronic kidney disease
- Pain or cramps in your legs while walking or exercising
- Problems with your legs and feet, including swelling, redness, trouble with walking, and wounds that are slow to heal
- Smoking, either current or past
- Your family history of PAD, heart disease, and other blood vessel diseases
During an exam to look for signs of PAD, your provider will:
- Check for weak pulses in your legs.
- Listen for poor blood flow in your legs. Your provider will use a stethoscope to listen for an abnormal whooshing sound, called a bruit.
- Look for problems on your legs and feet, including swelling, sores, or pale skin.
Conditions that can seem like PAD
Some conditions, such as arthritis or vein problems can cause leg pain, but the symptoms are different from those for PAD. A physical exam and your medical history can help your provider rule out these conditions.
However, problems with nerves can cause pain that may be confused with PAD. Sometimes a nerve is squeezed where it exits the spinal column. The result is pain that radiates, or spreads, from the hips or buttocks and down the leg.
To confirm that your pain is the result of PAD, your provider may ask you to stand up or change your position. Those movements often trigger nerve-related pain. In contrast, PAD pain is often brought on by leg exercise and is quickly relieved by rest with no need to change position.
Diagnostic tests and procedures
The ankle-brachial index (ABI) test is usually the first test used to diagnose PAD. The test compares blood pressure in your ankle with the blood pressure in your arm. Your provider uses a blood pressure cuff and device for this painless test.
A healthy ABI result is 1.00 or greater. If you have an ABI of less than 0.90 while resting, you may have PAD. An ABI of less than 0.40 is a sign of severe PAD. If there are problems with the arteries in your ankle, your provider may do a toe-brachial index (TBI) test instead, which measures the blood pressure in your big toe. A TBI less than 0.7 is abnormal. Be aware of your ABI, just as you know and keep track of your blood pressure numbers.
To diagnose PAD, your provider may also order some of the following tests and procedures:
- Blood tests check your cholesterol, triglyceride, and blood sugar levels.
- An exercise ABI test shows the severity of your leg symptoms and the level of physical activity that produces them. Your provider will do the ABI test after having you walk on a treadmill. This test may help them diagnose PAD when you have symptoms but your resting ABI test result is only slightly low. A drop of 20% or more in a post-exercise ABI is abnormal.
- A 6-minute walking test measures how far you can walk in a hallway in 6 minutes. Your provider may do this test to see how much PAD affects your ability to function and how serious your PAD is.
- Doppler ultrasound locates areas of reduced blood flow or blockages and measures how fast blood is flowing through the arteries. A handheld device is passed over your skin, and a computer converts sound waves into pictures of the blood flow in your arteries. Ultrasound can help diagnose PAD and monitor how well treatments for the condition have worked.
- Segmental Doppler pressure testing checks different parts of your legs for narrowed or blocked arteries. This method is similar to ABI testing but uses blood pressure cuffs placed at thigh, calf, and ankle levels. The ultrasound device amplifies the sounds of blood flow in your arteries, making it easier to measure the blood pressure in these areas of your leg.
Your provider may also order an imaging test using angiography to get a better picture of the blood vessels in your legs and feet. There are several types of angiography:
- Computed tomography angiography (CTA) allows providers to see the arteries in your legs and feet. A special dye is injected, and then X-rays are taken to show the location and extent of any blood vessel blockages.
- Magnetic resonance angiography (MRA) examines the structure of your leg arteries. MRA tests may not be safe for people who have metal implants in their body.
- Catheter-based angiography lets providers see inside the arteries of your legs. A doctor inserts a catheter, or tube, into an artery in your groin and guides it to the affected area. A special dye is released through the catheter and then X-rays are taken. Your provider may suggest this procedure for serious pain in the legs or feet or when treatments for PAD have not worked or other testing has not been helpful.