Popliteal Artery Entrapment Syndrome (PAES)

Diagnosis

When a patient presents with symptoms of popliteal artery entrapment syndrome (PAES), their doctor will conduct a thorough examination and inquire about their medical history. Due to the fact that PAES is most commonly observed in young and healthy individuals, diagnosing the condition can be difficult. Physical examination results may not indicate any abnormalities.

The doctor will eliminate other potential causes of leg pain, such as muscle strains, stress fractures, chronic exertional compartment syndrome, and peripheral artery disease. Peripheral artery disease is caused by the blockage of arteries.

To diagnose PAES, several tests are used to rule out other conditions and confirm the diagnosis:

• Ankle-Brachial Index (ABI). This is the first test used to diagnose PAES. During this test, blood pressure readings are taken in both your arms and legs before and after walking on a treadmill. The ankle pressure is then divided by the arm pressure to determine the ABI. Typically, the blood pressure in your legs should be higher than that in your arms, but if you have PAES, your ankle pressure may drop during exercise.
• Duplex ultrasound of the calf. This test uses high-frequency sound waves to measure the speed of blood flow in the leg arteries. The ultrasound may be performed before or after exercise or while you flex your foot up and down to engage the calf muscle.
• Magnetic Resonance Angiography (MRA). The calf muscle that is trapping the artery is shown. It can also show how much of the popliteal artery is blocked. During this test, you may be asked to flex your foot or press it against a board. This allows your doctor to determine how much blood is flowing to your lower leg.
• Computed Tomography (CT) angiography. This demonstrates which leg muscle is causing the artery entrapment. During this test, you may be asked to change the position of your foot, as with MRA.
• Catheter-based angiography. This shows your doctor how blood flows to and from your lower leg in real time. It is performed if the diagnosis remains ambiguous after other, less invasive imaging tests.

Treatment

When an abnormal calf muscle compresses an artery and causes symptoms that significantly affect your daily life or athletic activities, surgery is often recommended. During the surgical procedure, which typically takes about an hour and is performed under general anesthesia, the surgeon makes an incision on the inner calf just below the knee or in the back of the knee to release the abnormal calf muscle and provide more space for the artery. This prevents the calf muscle from compressing the artery in the future. Hospitalization for a day is usually required after the surgery.

In cases where the condition has persisted for a long time, artery bypass surgery may be necessary to treat severe narrowing of the artery caused by long-term popliteal artery entrapment syndrome. For the functional type of PAES, injections of Botulinum toxin A are the only non-surgical treatment available. Your healthcare provider will use CT or ultrasound guidance to inject Botox or Dysport into the muscle responsible for compression. This will temporarily paralyze the muscle in the hopes of causing it to shrink permanently.

However, this effect is short-lived and typically only lasts between three to six months. If the muscle does not shrink, symptoms will return. Success rates for this treatment have been reported to be less than 60% after one year.