A pseudoaneurysm, also known as a false aneurysm, is an outpouching of a blood vessel, involving a defect in the 2 innermost layer (tunica intima and media) with continuity of the outermost layer (adventia). Alternatively, all three layers are damaged and the bleeding is contained by a blood clot or surrounding structures. Given the increase in invasive cardiac procedures, damage to all three layers is the more common source of pseudoaneurysm.