An aortic aneurysm occurs when the aorta, the main vessel that carries blood from the heart to the body, bulges or dilates.

An abdominal aortic aneurysm (AAA) is located in the abdominal area, near the navel. Aneurysms can also occur in other parts of the aorta, but the abdomen is the most common site. Intact abdominal aortic aneurysms cause no symptoms however large aneurysms can burst or rupture causing heavy bleeding into the abdomen and/or death. A ruptured aortic aneurysm is a medical emergency requiring immediate treatment. AAAs are not related to aneurysms of the blood vessels in the brain.

AAA risk factors

AAAs are uncommon in people under the age of 60. On the other hand, they occur in 13 per cent of men and four per cent of women over the age of 65. Almost 90 per cent of aneurysms identified by screening are small, less than 4cm in diameter, and unlikely to burst.

In addition to age, other AAA risk factors include:

• Smoking

• Men develop AAA four times more often than women

• White people develop AAA more commonly than other ethnicities

• A personal history of coronary or peripheral vascular disease.

• Family history

Screening for AAA

The test used most commonly to screen for AAA is “abdominal ultrasonography”. A screening test is recommended in the following groups:

• Men age 65 to 75 who have ever smoked should be screened once for AAA. There is little benefit of repeat screening after a man has a single negative ultrasound as aneurysms develop and grow slowly. Men older than 75 are unlikely to benefit from screening.

• Men age 60 or older who have a sibling or parent with an AAA.

• There is no recommendation for general screening of AAA in women.

AAA symptoms

• Most abdominal aortic aneurysms are small and do not cause any symptoms.

• Some aneurysms cause a noticeable, small pulsating mass near the navel. This could be detected by a healthcare provider during a routine physical examination. Approximately 30 per cent of asymptomatic AAA are discovered in this manner; 70 per cent are identified during imaging of the abdomen.

• Some aneurysms can cause abdominal or back pain.

• Because blood can pool inside the aneurysm, clots could form then break loose, clogging a leg artery. This can lead to pain, pallor, coldness, numbness and foot tingling.

AAA treatment

Approximately 15,000 deaths occur each year in the US due to AAA rupture. Once rupture has occurred, the success rate of surgery is much lower than if surgery is performed electively, prior to rupture. The risk of rupture is mainly related to aneurysm size and its annual rate of expansion. For examples, if AAA size is between 4.0 to 4.9cm in diameter, rupture risk is 0.5-5 per cent per year; if it is above 6.0cm in diameter, it is 15-40 per cent.

The decision about whether and when to repair an asymptomatic aneurysm is based upon the risks associated with the aneurysm itself [rupture risk] and the risks of the repair [surgical risk].

Most people with an aneurysm less than 4.0cm in diameter are advised not to have immediate surgery, but rather to follow it by ultrasounds every six to 12 months. On the other hand, most patients with an asymptomatic aneurysm greater than 5.5cm in diameter, or one that expands more than 0.5cm within a six-month period are advised to have repair. People with an aneurysm between 4.0 and 5.5cm should discuss their options with a physician.

AAA can be repaired either through “open surgery” or with the use of an “endovascular stent graft”. Open surgical correction involves removing the section of the abdominal aorta that is dilated and replacing it with a prosthesis. With the endovascular approach, a stent graft is introduced from the groin and expanded inside the aorta, in a way to cover the aneurysm. Blood flows through the graft instead of the abnormally dilated aorta, which decreases the pressure on and risk of rupture of the aortic wall.

In next week’s column, thoracic aortic aneurysms will be discussed.

Joe Yammine is a cardiologist at Bermuda Hospitals Board. He trained at the State University of New York, Brown University and Brigham and Women’s Hospital. He holds five American Board certifications. He was in academic practice between 2007 and 2014, when he joined BHB. During his career in the US, he was awarded multiple teaching and patients’ care recognition awards. The information herein is not intended as medical advice nor as a substitute for professional medical opinion. Always seek the advice of your physician. You should never delay seeking medical advice, disregard medical advice or discontinue treatment because of any information in this article.