Pseudoaneurysm

Question 1

What is a pseudoaneurysm?

Answer 1

A false aneurysm where there is a break to the arterial wall.

This results in an accumulation of blood between the tunica media and tunica adventitia.

There is a direct communication between the vessel lumen and the aneurysm lumen, this means that they can grow bigger

Question 2

Causes

Answer 2

Damage to vessel wall from cardiac catheterisation or repeated injections as IVDU

Other causes include trauma, regional inflammation or vasculitis.

Question 3

Most common site to have a pseudoaneurysm

Answer 3

Femoral artery

Can also occur at radial artery, carotid, abdominal/thoracic aorta or splenic artery (from acute pancreatitis)

Question 4

Pseudoaneurysm and infection

Answer 4

Can occur in IVDU patients

The patient will quickly become septic and the pseudoaneurysm is likely to rupture.

Question 5

Clinical features

Answer 5

Pulsatile lump that can be tender and painful.

Distal arterial occlusion due to compression from the pseudoaneurysm might happen leading to limb ischaemia.

Question 6

Examination findings

Answer 6

If infected it can be erythematous and tender

Purulent material might be discharging

Features of sepsis

Question 7

What should be done about any patient that has had bleeding before from the pseudoaneurysm but has since then stopped?

Answer 7

They require close monitoring and urgent management

This might be a herald bleed and rebleed can resume at any point in time.

Question 8

Dx

Answer 8

True aneurysms

Haematomas

Abscess

Question 9

Investigations

Answer 9

Assess distal pulse status prior to any intervention

Gold standard = Duplex ultrasound which will show turbulent forward and backward flow called Yin-Yang sign.

CT imaging can be used if difficult to access Ultrasound.

Rouitine bloods + blood cultures and a pus MC&S if discharging.

Sufficienct blood units should also be cross-matched

Question 10

Management of small ones

Answer 10

Can be left alone

Question 11

Management of large or symptomatic

Answer 11

Ultrasound guided compression or thrombin injection.

Compression can be painful and requires 30 minutes of driect pressure of the neck of the pseudoaneurysm.

Question 12

Explain US-guided thrombin injection

Answer 12

Injection of thrombin directly into the lumen of the pseudoaneurysm under US guidance.

This forms a thrombus within in order to close it off.

Success with this technique is mainly in long and narrow necks pseuodoaneurysms.

Patient can then have a follow-up imaging to ensure resolution.

Question 13

What other approaches can be done?

Answer 13

Endovascular stenting

Surgical repair or ligation

Question 14

Why are endovascular stents not commonly done?

Answer 14

Because it can be difficult due to the location of the pseudoaneurysm where there might not be enough space to land a stent without covering a major branch.

Question 15

Explain surgical repair or ligation

Answer 15

Proximal and distal need to be controlled prior to opening the pseudoaneurysm.

A vein or bovine patch might be able to repair the defect.

Ligation might be required and a bypass graft subsequently.

Question 16

Management of infected pseudoanuerysm.

Answer 16

Much more likely to rupture or perforate.

Pressure dressing should be applied and urgent imaging.

They will require surgical ligation and a bypass graft subsequently.

A vein or bovine graft should be used since they are more resistant to infection

Tunnelling the graft through a non-infected area should be done.