Popliteal aneurysm

Overview – what is a popliteal aneurysm?

An arterial aneurysm is a swelling of an artery where it becomes 50% larger than it’s normal size. A popliteal aneurysm, is a swelling of the popliteal artery – which is one of the main vessels found in your leg. The popliteal artery is a blood vessel situated behind the knee joint. Here it branches out into three smaller arteries (the lower limb’s “arterial tree”) providing the blood flow to your lower leg and the foot. Popliteal aneurysms (also known as popliteal artery aneurysms) often remain undiagnosed until the sudden presentation of acute, limb-threatening symptoms.

Symptoms – popliteal aneurysms, what to look out for?

Popliteal aneurysms are relatively uncommon, with nearly half of the patients showing no clear symptoms (asymptomatic) at the time of diagnosis.

The exact number of people who may have suffered with them, is currently unknown due to a lack of evidence but a few studies suggest they can be more prevalent in the people aged between 60 and 70 years. They can be more frequently found in people who have abdominal aortic aneurysms. Which may suggest a genetic / inherited predisposition to the development of aneurysmal diseases.

Popliteal aneurysm – what are the risks?

Popliteal artery aneurysms (PAAs) are the second most common aneurysms after abdominal aortic aneurysms and the most common “peripheral” arterial aneurysms of the limbs.

The most frequent catastrophic complication is the acute ischaemia leading to irreversible nerve damage and gangrene (due to the lack of oxygen the nerves and muscles in the leg). This may inevitably lead to limb loss and/or life threatening sepsis and multi-organ failure.

More rarely, PPAs may burst causing a severe internal bleed (haemorrhage) in the leg; due to the compression exerted by the haematoma (bruise), this is often followed by the blockage of the artery (ischaemia): a “double catastrophe”.

Causes – what causes a popliteal aneurysm?

Arterial aneurysms can affect any artery of our body (aorta, limbs, brain and internal organs). Sometimes vessels can weaken and expand like a balloon, known as an aneurysm. More rarely, aneurysms can also be caused due to trauma or surgical procedures resulting in the damage of the arteries.

Wherever they occur within the body, aneurysms can lead to limb loss or life-threatening complications either in the form of a burst or ruptured artery or the sudden blockage of the artery (also known as acute ischaemia) due to the build-up of a clot inside the aneurysm sac. The clot can block the artery at the level of the aneurysm or can become detached and travel within the bloodstream, obstructing the circulation in the smaller arteries of the extremities.

Diagnosis – how can a popliteal aneurysm be diagnosed?

An accurate vascular assessment should include but not be limited to:

Medical and family history

To understand if any first-degree family members had any similar conditions

• History of abdominal aortic aneurysm (AAA) or popliteal artery aneurysms (PAA) within first-degree relatives
• Co-existent AAA

A physical examination

Where your healthcare professional should be checking for the following:

• Evidence of abnormally strong arterial pulses in the popliteal fossa (leg)
• Any signs and symptoms of restricted blood flow (acute lower limb ischaemia) – this would require an emergency, surgical intervention
• Whether you can feel or move the foot
• Excruciating pain progressively evolving towards numbness
• Irreversible coldness, pallor and mottling of the foot and leg

As part of your healthcare professional’s diagnostics they may also use / suggest the following:

• Duplex ultrasonography – to visualise the size and shape of the artery, and check for the presence of clot and the flow of blood within the lower leg
• CT-Angiogram or MRA scans – second level imaging for pre-operative assessment and planning

Treatment –  how is a popliteal aneurysm treated?

There are two key considerations for treatment:

Asymptomatic

Where the popliteal aneurysms are often larger than 2.5cm with a high risk of clotting and future complications. They should be considered for preventive treatment and monitored for surveillance with scans

Symptomatic

Where the popliteal aneurysm presents as an emergency due to a shortage of blood to the leg. Regardless of the size, it should be treated as high risk to prevent the possible amputation of the lower leg.

Traditionally, popliteal artery aneurysms have been treated surgically with open bypass surgical techniques. However endovascular techniques / keyhole surgery – which involve stent grafting (fabric lined metal mesh) through the popliteal artery aneurysm can also be used. Treatment will often be determined by your health and age and the complexity of the intervention needed.

Outlook if you’ve had a popliteal aneurysm

As having a popliteal aneurysm is high risk, it is important to attend for your surveillance scans. If the aneurysm reaches threshold size it will require surgery. This will be discussed with you by the vascular surgical team looking after you. Currently after surgery the chance of re-occurrence is low.

Prevention – how to avoid getting a popliteal aneurysm

There are a number of things you can do to try and avoid the possibility of getting a popliteal aneurysm:

• Don’t smoke
• Manage blood pressure
• Take regular exercise
• Manage cholesterol
• Maintain a healthy weight

Harm – the risk factors of getting a popliteal aneurysm

• Not treating in a timely manner
• Not checking legs properly or doing basic checks, such as a Doppler test
• Not attending for surveillance scans

Learn more about harm