The National Institute for Health and Clinical Excellence (NICE) has issued full guidance to the NHS in England, Wales, Scotland and Northern Ireland on thrombin injections for pseudoaneurysms.
This is an injection treatment for pseudoaneurysms. A pseudoaneurysm is a collection of blood contained by clot that has formed outside a blood vessel following an injury. The collection is attached by a channel to the blood vessel so blood flows within it. A pseudoaneurysm may rupture and bleed severely.
Pseudoaneurysms (also called false aneurysms) differ from true aneurysms in that blood within a true aneurysm is contained by the weakened wall of the blood vessel, not clot alone.
The most common cause of pseudoaneursym is femoral artery puncture during cardiac catheterisation. About 100,000 cardiac catheterisations are performed in England each year (source: Department of Health Hospital Episode Statistics, ungrossed for missing data, 2000/2001). Up to 2% of cardiac catheterisations lead to pseudoaneurysm formation.
Pseudoaneurysms may also occur following other procedures that involve puncture of an artery, including removal of an arterial blood pressure line or intra-aortic balloon pump, or following accidental trauma.
Many pseudoaneurysms resolve spontaneously and need no treatment. The standard treatment for an unresolved pseudoaneurysm is surgical repair under general anaesthetic. This may be dangerous in people with cardiac disease. Other options include prolonged compression, which is time consuming and painful, and packing the pseudoaneurysm with metal coils, which leaves a lump in the groin.
Thrombin is an agent that causes clotting. It may be injected under ultrasound guidance into the pseudoaneurysm to clot the blood inside it. The clot is gradually reabsorbed. The procedure is performed under local anaesthetic.