Pseudoaneurysm

A pseudoaneurysm, also known as a false aneurysm, is a locally contained hematoma outside an artery or the heart due to damage to the vessel wall. The injury passes through all three layers of the arterial wall, causing a leak, which is contained by a new, weak "wall" formed by the products of the clotting cascade. A pseudoaneurysm does not contain any layer of the vessel wall. This differentiates it from a true aneurysm, which is contained by all three layers of the vessel wall, and a dissecting aneurysm, which has a breach in the innermost layer of an artery and subsequent dissection/separation of the tunica intima from the tunica media. A pseudoaneurysm, being associated with a vessel, can be pulsatile; it may be confused with a true aneurysm or dissecting aneurysm. The most common presentation of pseudoaneurysm is femoral artery pseudoaneurysm following access for an endovascular procedure, and this event may complicate up to 8% of vascular interventional procedures. Small pseudoaneurysms are capable of spontaneous clotting, while others require surgical intervention. A pseudoaneurysm may also occur in a chamber of the heart following myocardial damage due to ischemia or trauma. A pseudoaneurysm of the left ventricle is a potentially lethal complication of a heart attack. Pseudoaneurysms usually present as a painful, tender, pulsatile mass. The overlying skin is sometimes erythematous (red). They can sometimes be confused with abscesses. The patient may describe a history of catheterization or trauma, and they may note that the pulsatile mass is gradually expanding. The diagnosis should be suspected if the patient has a history of arterial trauma. This can include arterial access for catheterization (i.e. the common femoral artery), blunt trauma (i.e. to an extremity), or penetrating trauma (i.e. gunshot or blast injury). Blunt or penetrating trauma can cause a disruption in the arterial wall, leading to a pseudoaneurysm. A patient with such a history who presents with a painful, pulsatile, tender mass at the site of catheterization or trauma should be suspected to have a pseudoaneurysm.