By Dr Ananya Mandal, MD
Abdominal aorta aneurysm may be treated in two ways - preventive treatment and emergency treatment. Under preventive treatment the aim of surgery and medical therapy is to prevent the rupture of the aneurysm. Under emergency treatment is the repair of the aneurysm after it has ruptured. Preventive surgery carries its own risks and is usually only recommended if the risk of a rupture is high enough to justify the risk of surgery.
Preventive treatment of abdominal aorta aneurysm
To undertake preventive surgery first a risk assessment is made to determine the likelihood of the aneurysm rupturing. This is based on the age of the patient, general health (ability to withstand surgery), size of the aneurysm, rate of growth of the aneurysm, history of ruptured aneurysm in a sibling or a parent etc. Another marker for risk assessment is high level of a chemical called MMP-9 in blood. High levels of MMP-9 can be caused by extensive weakening of the aortic wall.
Observation and ultrasound
For those with an abdominal aortic aneurysm less than 5cm, observation with repeated ultrasound examinations is usually recommended. The ultrasound scans are prescribed every three to six months to check for any growth of the aneurysm.
If the aneurysm is 5–5.5cm (2–2.2 inches) and there is presence of risk factors that may cause rupture, a preventive surgery is advised. Surgery is usually recommended if the aneurysm is larger than 5.5cm regardless of whether there are other risk factors present.
In all cases lifestyle changes including quitting smoking is recommended strongly as smokers usually have faster-growing aneurysms than non-smokers and the larger the aneurysm, the higher the risk of it rupturing. Patients are advised to take regular physical exercise and a healthy balanced diet in order to maintain a healthy body weight.
Medications are advised to keep other risk factors in check. For example, those with high blood cholesterol are given cholesterol lowering medications like statins and those with high blood pressure may be given angiotensin-converting enzyme (ACE) inhibitors etc.
The most commonly used surgical treatment for an abdominal aortic aneurysm is grafting. For this the affected section of the aorta is removed and is replaced with a piece of synthetic tubing known as a graft. This is also called a stent graft and holds the aorta open like a scaffold. Grafting may be done with two approaches - open surgery where a large incision is made over the abdomen and the surgery is performed, and endovascular surgery where a thin tube called a catheter is inserted into one of the arteries in the legs and the graft is guided within the catheter into the aorta. When the graft reaches the right place as seen with constant imaging of the abdomen, it is placed at the site of the aneurysm to reinforce the aorta wall. In most cases endovascular surgery is recommended as it has better outcomes than open surgery for preventing death from a ruptured aneurysm and other complications.
Emergency treatment of ruptured abdominal aorta aneurysm
Emergency treatment for a ruptured aortic aneurysm is based on the same lines as preventive surgery. Similar grafts are used to repair the ruptured aneurysm. However, time is of vital importance in these cases and there is need for additional medication and treatments to prevent blood loss and organ damage. For example, nimodipine is given to prevent ruptured blood vessels going into spasm and causing further blood loss. Blood transfusion may also be given.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)