Pseudoaneurysms

Interesting case in the emergency theatres today. 40yr old male with a large hematoma in the left thigh. One week ago he underwent a cardiac procedure that required the use of an intra-aortic balloon pump.
Have an idea yet?
Insertion of an IABP is through a catheter in the femoral artery, if this puncture is misplaced or compression afterwards to close the wound is insufficient then the artery can continue bleeding into the thigh and form a pseudoaneurysm.
This chap had a pseudoaneurysm for exactly that reason, in fact you could see on doppler-ultrasound the hole was in the superficial femoral artery. The superficial femoral artery is a common origin of pseudoaneurysms because when you apply compression to the leg after cath lab or interventional radiology procedures for hemostasis, the femoral bone is not behind (as it would be for a standard common femoral artery puncture), so compression is ineffective.

What is a pseudoaneurysm?
Usually the result of injury to an arterial wall a pseudoaneurysm is an aneurysm lacking all three normal elements of an arterial wall. Pulsatile flow from the ruptured artery dissects the neighbouring tissues and forms a false lumen or sac containing the hematoma.

Risk factors: are any intra-arterial puncturing procedure, which increases in proportion to the size of catheter (larger catheters having higher rates of pseudoaneurysm formation). The risk is increased when the puncture site is not the common femoral artery eg. external iliac, superficial femoral and profunda femoral arteries.

How do you diagnose a pseudoaneurysm?
Most common presentation is pain and swelling in the groin area. Often the pain is disproportionate to the pain expected from the procedure. Large hematomas can compress neighbouring nerves and veins, and even cause skin necrosis.
Conduct peripheral pulse examination, ankle-brachial index and ultrasound scan of the area.
The best intial diagnostic test is a duplex ultrasound scan (7mhz linear probe). you can find and measure the diameter of the pseudoaneurysm neck.
If a doppler US scan cannot be performed the next step is a CT scan with contrast.

Management and treatment
So after support and resuscitation (a ruptured pseudoaneurysm can lead to catastrophic bleeding).
there are four main treatments:

1. Observation: for small pseudoaneurysms, less than 2cm. these will often spontaneously heal within a few weeks. keep monitoring with regular ultrasound scans. disadvantages include prolonged hospital stays and restricted activity.
2. US-guided compression: very variable success rates, the compression has to be maintained for at least 15minutes, aim for 20minutes. the probe can be used to target the pseudoaneuryms neck accurately. disadvantages include the fact that it not tolerated well and can be challenging. 
3. Percutaneous thrombin injection: guided by US thrombin is injected into the pseudoaneurysm cavity for immediate thrombosis. the real risk of embolism limits the procedure to pseudoaneurysms with a neck smaller than 4mm. often a well tolerated and successful procedure it does require anticoagulation therapy. 
4. Open surgical repair: Best for patients with complications or contraindicated to non-surgical management. open surgical repair allows direct visualization and control of the bleeding with suturing of the puncture site or patch angioplasty. hematoma can be evacuated and compression symtoms relieved. there are of course risks with any surgical procedure with  wound infction, lymphocele, radiculopathy and myocardial infarction topping the list. (make sure you check both sides of the artery).

So our patient had intially complained of a small thigh hematoma a few days after the cardiac procedure, he was infact in ITU with respiratory problems (complicated history). The surgeon had a look and since it was small and also considering the state of the patient, opted for the observation approach. so four/five days later the hematoma had expanded rapidly and considering the blood loss and size, open surgical repair was the best option. Operation went well, chap is doing fine. the hole was easily controlled with a controlled stitch and the hematoma evacuated from the anterior thigh and inguinal area. 

(pseudoaneurysm after arterial puncture to the superficial femoral artery)