Popliteal Artery Entrapment Syndrome

University of Maryland Medical Center's Rajabrata Sarkar and Jonathan Packer

Treatment for popliteal artery entrapment syndrome is led by Rajabrata Sarkar, MD, PhD, left, and Jonathan Packer, MD.

Popliteal artery entrapment syndrome occurs when the popliteal artery, the main artery for the lower body, is compressed by muscles behind the knee, restricting blood flow through the legs.

The disease presents in two ways: congenitally and developmentally.

Congenital variations are present at birth when the course of the artery is altered by one of the muscles in the area behind the knee. This can remain without symptoms or can cause significant problems if the artery becomes compressed and eventually blocked.

Developed conditions are usually seen in athletes and competitive runners when the muscles are in the correct position but compress the artery as they grow.

This is a difficult diagnosis in many centers because most physicians do not expect vascular disease to occur in young patients. This can delay the diagnosis.

There are also other diagnoses that can mimic popliteal artery entrapment, like chronic compartment syndrome of the lower extremity, knee joint pain, or other problems with the muscles in this area.

The diagnosis is made by non-invasive testing using MRI, MRA or CT scan with contrast. We also use ultrasound-based, non-invasive vascular lab testing, and measurements of the flow and pressures.

In cases which are difficult, such as those with functional PAES, we often have to perform an angiogram, in which the patient moves the leg in different ways to induce the symptoms and we measure blood flow under these conditions.

Popliteal Artery Entrapment Syndrome compresses the popliteal artery, the main artery to the lower extremity, and is particularly noticeable during exercise. People with this condition develop pain with walking or during strenuous exercise. In the early stages of the disease, this occurs usually at a distance of 1-3 blocks, or 5-10 minutes.

If the disease progresses and the artery becomes blocked because of the compression over time, blood flow at rest is compromised and the leg can be in jeopardy.

If the compression is caught early and the artery itself remains undamaged, relieving the muscle, tendon or other compression structures can restore normal blood flow to the leg under resting and exercising conditions.

In advanced cases, the compression has built up for a long time and actually damages the lining (inside) of the artery. This can cause permanent structural changes in the artery and can completely block the artery. 

Once the artery is completely blocked, simply relieving the external compression will no longer restore flow because the artery itself has been damaged. In these cases, a bypass with either a vein or a synthetic graft is required to restore normal blood flow to the legs and to relieve the symptoms.

The long-term outcome for these patients is good if this diagnosis is made correctly and action is taken to correct the problem.

Here at the University of Maryland Medical Center, we've seen cases of patients in whom the diagnosis has been delayed, or the surgery has been done incorrectly or ineffectively. In these patients, a careful diagnostic evaluation, often including an angiography, can identify the problem and lead to a solution that is durable and effective.

High schooler Riley Shipley thought her athletic career was over and that she could lose her leg. When she came to the University of Maryland Medical Center, she was correctly diagnosed with popliteal artery entrapment syndrome and cured by University of Maryland physicians, allowing her the opportunity to continue her athletic career.