Aortic Aneurysm - Preventing Rupture

aortic aneurysm
Aortic Aneurysm. SCIEPRO/Getty Images

If you have been told you have an aortic aneurysm, it means that a localized section of your aorta has developed a balloon-like dilation, known as an aneurysm. The reason an aortic aneurysm is important is that it has the potential to rupture. A ruptured aortic aneurysm is a catastrophic event that often leads to rapid death.

What this means is that you and your doctor must decide whether your aneurysm poses a sufficient risk of rupture that it ought to be treated now, or whether it can be safely monitored over time.

This article will help you learn what you need to know about aortic aneurysms, so you can make the decision that is right for you.

Aortic Aneurysms

The aorta is the main artery of the body. All the blood pumped by the heart enters the aorta, which gives off branches to all the body’s organs. The aorta itself is a long, large artery that goes from the heart all the way to the lower abdomen. 

With certain medical conditions - including hypertensionatherosclerosis, and simply aging - the wall of the aorta becomes weak. This weakness can produce a localized bulge in the wall of the aorta - an aneurysm. Because the wall of an aneurysm is weakened, it is prone to rupture. Rupture of the aorta usually produces immediate and massive internal bleeding, and, most often, rapid death.

Aortic aneurysms can appear in the chest (thoracic aortic aneurysm) or in the abdomen (abdominal aortic aneurysm).

 

Aortic aneurysms occur much more commonly in men than in women, and are pretty rare in people under 60 years of age. A family history of aortic aneurysm is an important risk factor, as is hypertension. But smoking, by far, is the major risk factor. Smokers have a 5-fold increase in the incidence of aortic aneurysms compared with non-smokers.

What Are the Symptoms of an Aortic Aneurysm?

Most people with aortic aneurysms have no symptoms at all. Occasionally an aneurysm will produce pain in the chest, belly or back. If so, these symptoms may indicate that the aneurysm has recently grown, and may be a sign that a rupture is likely to happen. However, most ruptures occur in people who have had no prior symptoms.

In addition, clots may form within an aortic aneurysm. Such a clot can break off and cause organ damage, such as stroke.

Rupture

A rupture of an aortic aneurysm is a catastrophic event. Most ruptures cause sudden, major internal bleeding. and are often quickly fatal. Patients who survive long enough to get to an emergency room usually have severe abdominal or back pain, and a dangerously low blood pressure. Only about 25% of patients who suffer a ruptured aortic aneurysm will survive. In fact, a rupture of an aortic aneurysm is an important cause of unexplained sudden death in older people.

How is Aortic Aneurysm Diagnosed?

Because the initial symptoms of an aortic aneurysm are most often due to rupture, and because rupture is most often fatal, ideally the aneurysm should be diagnosed before it produces any symptoms.

It is usually difficult to diagnose an aortic aneurysm by physical examination. Only 30% of abdominal aortic aneurysms are initially detected during a physical exam, and the percentage is much lower for thoracic aneurysms. So most pre-rupture aortic aneurysms are diagnosed when people who are judged to be at increased risk are specifically screened for it, usually with an ultrasound (echo) study.

Which individuals should be screened for an aortic aneurysm, and when to screen them, turns out to be a controversial question. Learn more about whether you should be screened for an aortic aneurysm.

Who Should Be Treated For Aortic Aneurysm?

If you have been told you have an aortic aneurysm, you and your doctor will have to decide whether you should have surgical repair to prevent rupture, or instead whether your aneurysm should be carefully monitored over time. To a large extent, this decision will depend on the estimated likelihood that your aneurysm will rupture, and on your estimated risk from surgery.

Many people with aortic aneurysms have other cardiovascular disorders (due to their age and risk factors), so the risk of surgical repair is often not trivial. In general, the risk of dying from the surgical procedure is usually about 5% or less, but the risk of surgery has to be carefully assessed for each individual. 

The likelihood that an aortic aneurysm will rupture appears to depend largely on two factors: the size of the aneurysm, and its rate of growth. 

The size is considered the best indicator of the risk of rupture. The size of an aortic aneurysm can be measured by ultrasound testing, CT scan, or MRI. Aneurysms greater than 5.5 cm in diameter in men, or greater than 5.0 cm in women, are dramatically more likely to rupture than smaller aneurysms. If these "threshold" diameter values have been reached, the risk of rupture is greater than 40% over five years, and surgery is often recommended. Below these threshold values, the risk of rupture is usually similar to the risk of complications from surgery, so surgery is often not recommended.

If surgery is not recommended, then regular reassessments of the size of the aneurysm should be made. If the aneurysm grows in size by more than 0.5 cm in a year, the risk of rupture is much higher - and surgery is usually recommended even if the overall size of the aneurysm is still less than 5.0 or 5.5 cm.

How is AAA Treated?

The treatment of AAA is usually surgical. Learn more about the treatment of AAA.

Summary

Having an aortic aneurysm usually presents a person with a difficult choice. These aneurysms generally causes no difficulties whatsoever until it produces a sudden medical catastrophe. So you are faced with having to choose when - and whether - to have a relatively big surgical procedure to prevent such a catastrophe. This choice is often only made more difficult by the fact that you may be feeling just fine right now.

The right decision for you will depend on your own medical condition, the size and the rate of growth of your aneurysm, and a careful balancing of your overall individual risks in taking action now versus watchful waiting. So making the best decision will require close cooperation and excellent communication between you and your doctor.

Sources:

Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation 2010; 121:e266.

Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA 2005 Practice Guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Association for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease): endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation. Circulation 2006; 113:e463.

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