Aortic Abdominal Aneurysms (AAA) or Triple ‘A’ as they are commonly known has an incidence of 21 cases per 100,000 person-years in the west. There are about 15,000 deaths every year from this disease. What is worse that the incidence of rupture in about 4.4 % and is many cases proves fatal. It is the thirteenth leading cause of death in the west.
Aneurysm is a dilated artery and the aorta is the size of the garden hose pipe connecting the heart with the rest of the body and passing through the mind-line of the chest and the abdomen.
Since it is the main supplier of the blood to the entire body, its rupture leads to life threatening bleeding.
Depending on its size and the rate of its growth the treatment varies from observation to emergency surgery which is not only very risky but has an exceptionally high mortality.
How do they present?
Mostly the patients are asymptomatic and are diagnosed on an ultrasound of the abdomen performed for some other problem.
Some however grow rapidly and it is not possible to predict which ones shall behave this way.
Once large then the patient may note:
- A pulsatile mass around the belly button.
- Deep constant ache in the abdomen.
- Back ache.
When to see a doctor?
- Should you have any of the complaints listed above.
- Anyone over 60 years who is a smoker and has a family history of AAA should be screened regularly.
- There are no specific guidelines for females.
Why does it happen?
The exact cause is unknown but there are aggravating factors:
- Tobacco use – this is the leading cause and directly affects the arteries. It promotes plaque formation, high blood pressure, and causes the aneurysm to grow faster by further damaging the aorta.
- Athersclerosis – it is the deposit of fat in the wall of the artery thus increasing the risk of aneurysm.
- Vasculitis – it is the infection of the arterial wall. It leads to the weakening of the arterial wall leading to the formation of the aneurysm.
Who are more prone?
- Age – over 65 years is commoner.
- Tobacco abuse – this is a strong risk factor and the damage to the aorta is directly proportional to the length of smoking.
- Atherosclerosis –deposit fat in the arterial wall which damages it and increases the risk of the aneurysm.
- Sex – it is commoner in males.
- Family history – those with a strong family history have a higher incidence of AAA, at a younger age and greater chances of rupture.
How does one know that the AAA has burst?
- Sudden pain in the abdomen or back which persists
- Sweating – cold and clammy
- Nausea and vomiting
- Unrecordable blood pressure
- Rapid pulse
- Loss of consciousness
How can you help yourself?
You can help yourself by making lifestyle changes – by quitting smoking, eating a healthy diet, and exercising daily.
How do you diagnose AAA?
1. Ultrasound is the investigation of choice for detecting AAA.
CT Angiogram – This shows the anatomy of the arterial tree and the aneurysmal dilatation though the size is better seen on ultrasound because of clots in the aneurysmal wall.
MRI screening – This is also a painless screening test. It contains a large magnet encircling a table on which the patient lies and this table slides into the tunnel. The magnetic field aligns atomic particles in some of your cells. When radio-waves are broadcast towards these aligned particles they produce signals that vary according to the tissue they are. The images produced by these signals show if there is an aneurysm.
How are such patients treated?
Small aneurysms – These are less than 4 cm in diameter. Mostly in these cases wait and watch policy is adopted. Surgery is not advised because the risk of surgery outweighs the risk of rupture. Routine serial ultrasound is done 6-12 monthly and the patient is warned that if he develops abdominal tenderness and backache (possible signs of dissection) he should report to the casualty immediately.
Medium aneurysms – these range between 4 – 5.3 cm diameter. In this case there are no guidelines comparing risk of surgery to rupture and so one has to discuss with his surgeon about the decision to leave alone or operate. If we decide to wait and watch then do ultrasound every 6 months and note the growth rate of the aneurysm.
Large or fast growing or leaking aneurysms – These are over 5.6 cm diameter or growing over 0.5 cm every 6 months. You will need surgery.
A leaking tender aneurysm is an emergency.
What are the types of surgery?
There are two ways to treat AAA.
1. Open abdominal surgery – Here we replace the damaged segment of the aorta with a synthetic graft which is sewn in place. By this technique it takes about one month to recover.
2. Endovascular surgery – This is less invasive. The graft is attached to a thin catheter that is inserted into a groin artery and threaded up the aorta. The graft is a woven tube covered by a metal mesh support. It is placed at the site of the aneurysm and fixed in place by small hooks. The graft reinforces the diseased aorta and prevents its rupture.
The recovery time in case of endovascular surgery is short and takes 3-4 days to a maximum of one week. The follow-up appointments are more frequent because of the fear of leaks. They are done 6 monthly for the first year and then yearly. Long term survival rates are the same for both.
What are the lifestyle changes needed?
- Quit smoking or chewing tobacco
- Keep blood pressure under check.
- Regular exercise.
- Reduce cholesterol and fat in diet.