An abdominal aortic aneurysm is a widening or “ballooning” of a part of the abdominal aorta.
The aorta is a large blood vessel which carries blood rich in oxygen from the heart to every part of the body. It passes from the heart through the chest area and then down through the abdominal area. Around the navel (bellybutton) it branches into two smaller vessels to supply the legs. This section of aorta in the abdomen is called the abdominal aorta.
An abdominal aortic aneurysm is a widening or “ballooning” of part of the abdominal aorta. This is most commonly due to hardening of the arteries (arteriosclerosis) which causes an area of the wall of the aorta to become weakened. The pressure of the blood being pumped through the aorta causes the weakened area to bulge. Many people with an abdominal aortic aneurysm have no symptoms and it is often only discovered while having investigations done for other reasons.
Image below found at Care Hospitals
Who is most likely to have an abdominal aortic aneurysm
Abdominal aortic aneurysms are found mostly in the over 60 year old age group and are more common in men than women. The person will often have a history of some or all of the following; high blood pressure, diabetes, high blood cholesterol level and smoking.
What is the treatment for an abdominal aortic aneurysm
Abdominal aortic aneurysms which have no symptoms and are 5cms or less in width do not require surgery. They are monitored every 6 to 12 months by scanning (ultrasound) the abdomen and high blood pressure is controlled with medication. Smoking is discouraged. Some patients who are young and healthy may decide to have surgery for aneurysms between 4 and 5cms. Aneurysms will usually require surgery if they are larger than 5cm, getting larger or causing symptoms.
There are two main methods of repairing a AAA: the open approach and a stent graft. When the patient has an open operation the area of aorta affected by the aneurysm is cut open and a tube of synthetic material inserted to provide a safe channel for the blood to flow through. The aneurysm is then sewn around the synthetic material.
These days the aneurysm can in some cases be repaired by a method called a “stent graft”. This does not involve the abdomen being opened. Instead the aneurysm is reached by a thin tube (catheter) passed into a blood vessel through a small cut made in the groin. Attached to the catheter is a long capsule containing a tube of synthetic material encased in a collapsed metal-mesh cylinder. When the catheter reaches the area of the aneurysm the stent is activated and springs open and attaches itself to the wall of the aorta. The synthetic tube now provides a safe passage for blood flow.
Patients having this method of treatment generally have shorter stays in hospital and are back on their feet quicker than those having the more traditional operation.
What are the complications an abdominal aortic aneurysm?
The big risk with large abdominal aortic aneurysms is rupture which is a medical emergency. A lot of blood is lost and the patient quickly becomes shocked. Survival rate is less than 50%.
A blood clot can easily form in the aneurysm and a piece can break off and get stuck in the smaller blood vessels in the legs. This blocks blood supply beyond this point and urgent treatment in hospital is required to stop the tissue in the leg from dying.
What happens in ICU?
- Monitoring - Blood pressure is displayed continuously on the bedside monitor via an arterial catheter . Heart monitoring with electrocardiograph (ECG) is displayed on the bedside monitor. Oxygen levels are checked by a blood sample from the arterial line and by a probe attached to the finger.
- Medication to control blood pressure is often given as an infusion at first via a rate controlled pump. This allows for strict blood pressure control. When the patient is fully awake and able to swallow blood pressure tablets may also be given.
- Circulation to the legs is assessed regularly to observe for new signs of reduced blood flow to the area.
- Urine output is monitored via a tube (catheter) in the bladder to assess kidney function.
- Pain relief is provided as necessary.
- Artificial Ventilation may be required in some instances.
How long will the patient remain in ICU?
Generally the patient needs to stay in the Intensive Care Unit for one or two days following repair of an abdominal aortic aneurysm. The stay following repair of a ruptured aortic aneurysm however is considerably longer.
The information contained on this page is general in nature and therefore cannot reflect individual patient variation. In addition it reflects Australian intensive care practice which may differ from other countries. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. ICCMU attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.
Abdominal Aortic Aneurysm Version 1 Author Deirdre Moran CNS RNSAH First published February 2008