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Known as a false aneurysm.
It is a collection of blood that forms between the two outer layers of an artery, the tunica media and the tunica adventitia.
It is usually caused by a penetrating injury to the vessel, which then bleeds, but forms a space between the above two layers, rather than exiting the vessel.
It may be pulsatile
It can resemble a true aneurysm, but a true aneurysm involves all three layers of the blood vessel.
Femoral pseudoaneurysms may occur in up to 8% of vascular interventional procedures.
Small pseudoaneurysms can spontaneously clot, while others need definitive treatment.
It may also occur in the heart following myocardial damage due to ischemia or trauma.
A pseudoaneurysm of the left ventricle that forms after a myocardial infarct is potentially lethal.
Usually presents as a painful, tender, pulsatile mass.
The overlying skin is sometimes erythematous reddened and can sometimes be confused with abscesses.
A history of catheterization or trauma is frequently present.
It may be noted that the pulsatile mass is gradually expanding.
Diagnosis should be suspected if the patient has a history of arterial trauma.
Such arterial trauma includes: arterial access for catheterization to the the common femoral artery, blunt trauma to an extremity, or penetrating trauma such as a gunshot or blast injury.
Trauma can cause a disruption in the arterial wall, leading to a pseudoaneurysm.
A patient with a painful, pulsatile, tender mass at the site of catheterization or trauma should be suspected to have a pseudoaneurysm.
The diagnosis can be confirmed using Duplex ultrasonography, which will reveal arterial blood flow into the pseudoaneurysm.
A CT angiogram or conventional angiogram can also diagnose a pseudoaneurysm.
It is important that the diagnosis be confirmed before. procedures are performed as incision and drainage of a suspected abscess, which instead is a pseudoaneurysm, could lead to extensive hemorrhage.
It can form in communication with any artery in the body.
Femoral artery pseudoaneurysms, and pseudoaneurysms of arteriovenous fistulas used for hemodialysis, are the most common.
They can form in the days, months, or even years after trauma.
Aneurysms in the posterolateral wall of the ventricle are frequently due to pseudoaneurysms.
Can occur in the aorta as a consequence of traumatic aortic rupture.
Can be associated with pancreatitis that occur in several of the abdominal vessels, including the superior mesenteric artery and pancreaticoduodenal artery.
Treatment
Surgery was the primary treatment in the past.
A covered stent may be placed endovascularly across this hole to prevent it from receiving blood flow from the artery.
As the covered stent remains in place permanently, and without a continuous flow of arterial blood, the pseudoaneurysm will then thrombose.
The advantage of endoscopic stent placement is that it has a high success rate without the need for an open surgery.
Complications of endoscopic stent placement include: migration, persistent leakage of blood into the pseudoaneurysm, breaking of the stent, and infection of the stent or of the arterial insertion site.
An ultrasound probe can be used to compress the neck of the pseudoaneurysm for usually about 20 minutes.
During US compression the blood within the pseudoaneurysm clots, and will not continue to expand.
The US compression procedure is the least invasive method of stopping arterial blood flow into a pseudoaneurysm.
Ultrasound-guided thrombin injection is a minimally-invasive technique can be used as it is a clotting factor that converts fibrinogen into fibrin, which then polymerizes to form a blood clot.
Ultrasound-guided thrombin injection is easy to perform, successful, and is minimally invasive.
It is contraindicated if there is an arteriovenous fistula, in addition to the pseudoaneurysm, and occurs with about 10% of pseudoaneurysms.
Open surgical ligation may be performed to remove pseudoaneurysms or prevent them from expanding.
The pseudoaneurysm may be ligated both proximally and distally to the pseudoaneurysm, and may or may not be removed.