Abdominal Aortic Aneurysms Can Kill You: Are You at Risk?
An aneurysm is permanent dilatation of the wall of the heart or of an artery (blood vessel that carries blood away from the heart). The largest artery of the body, the aorta, receives blood from the heart and sends branches to the rest of the body. The thoracic aorta travels through the chest and becomes the abdominal aorta once it enters the abdominal cavity as it passes below the diaphragm. Abdominal aortic aneurysms (AAA) are the most frequent type of aortic aneurysm.
Risk factors for developing an AAA include advancing age, cigarette smoking, high blood pressure, high cholesterol, male gender, emphysema, obesity, and certain genetic factors. Infections or injuries may also cause AAA. The one group that Medicare recommends screening for AAA are men aged 65 to 75 years old who smoke or who have ever smoked.
An AAA will likely remain asymptomatic even as it enlarges. However, symptoms of abdominal and/or back pain may develop. Nerves may become compressed by the aneurysm and cause leg pain or numbness. The dilated vessel may contain clotted blood or cholesterol deposits that can break off and travel to the kidney or legs resulting in clogged blood vessels in those areas. The size of a normal abdominal aorta is 2.0 cm. An AAA is present when the abdominal aortic diameter is 50% above normal, that is greater than 3.0 cm.
Aneurysms are often found accidently when an individual has an imaging study, such as an ultrasound, CT scan, MRI scan, or angiogram of the abdomen for a reason other than a search for an aneurysm. They occasionally are discovered as a pulsatile abdominal mass but this is usually in thin individuals. Once an aneurysm is found, it is often evaluated by ultrasound of the abdomen every 6 to 12 months with repair recommended if it grows to be more than 5 cm in diameter or the diameter increases by more than 1 cm within a year.
The major complication of an AAA is a rupture. This results in a large amount of blood spilling out into the abdominal cavity or into the tissues behind the abdominal cavity. This can lead to death within minutes in up to 90% of patients. The risk of rupture increases as the diameter of the aneurysm increases, especially as the diameter increases above 5.0 cm. Above 5.0 cm, the risk of rupture each year is 3 to 15%. This is why aneurysms should be repaired if they grow above this size. Repair can be achieved by an endograft. This is a large sleeve that is passed within the abdominal aorta to cover the aneurysm on the inside. This can only be done when the top of the aneurysm is below the point where the arteries to the kidneys come off the aorta. The other option is for a surgeon to open the abdomen and replace the aneurysmal portion of the abdominal aorta with a graft.
The occurrence of AAA in men greater than 60 years old was determined to be 2 to 6% and somewhat less frequently in women. It causes 15,000 deaths per year in the United States. Early detection and appropriate intervention can prevent many of these deaths.
Dr. Peter Lemis is a Board Certified Cardiologist with Jefferson Cardiology Association. For more information, call (412) 469-1500 or visit jeffersoncardiology.com.
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