Popliteal artery aneurysms

How and where do arterial aneurysms develop?

acute ischaemia) due to the build-up of the clot inside the aneurysm sac; the former is more typical of aortic or brain aneurysms, while the latter is more frequent in peripheral aneurysms of the leg. The clot can block the artery at the level of the aneurysm or detach and travel in the bloodstream, obstructing the circulation in the smaller arteries of the extremities.

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 being the acute ischaemia (see above) 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”.

How do popliteal aneurysms present?

Poplitelal aneurysms are often silent. Nearly half of the patients with PAAs have no symptoms at the time of diagnosis.

The exact incidence of PPAs is not known as no population-based study has been published; however, a few studies suggest that PPAS are more prevalent in the population aged 60 – 70 years. PPAs are more frequent in persons who have abdominal aortic aneurysms (AAAs). This suggests a genetic predisposition to the development of aneurysmal disease.

How can a popliteal aneurysm be detected?

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

Medical and family history

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

A physical examination

• Evidence of abnormally strong arterial pulses in the popliteal fossa
• Signs and symptoms of acute lower limb ischaemia (surgical emergency!)
  • Sudden sensory and motor nerve impairment (can’t feel or move the foot)
  • Excruciating pain (progressively evolving towards numbness)
  • Irreversible coldness, pallor and mottling of the foot and leg

• 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

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.

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.

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