Abdominal Aortic Aneurysm
An abdominal aortic aneurysm (or AAA) is an enlarging or bulging area in the wall of the abdominal aorta, which is the the largest artery in the body. The larger the aneurysm becomes, the greater the risk of rupture or death. The most common location of an aneurysm is the abdominal aorta, which is the segment of the abdominal aorta below the kidneys. An abdominal aneurysm located below the kidneys is called an infrarenal aortic aneurysm.
Because an aneurysm may continue to increase in size, along with progressive weakening of the artery wall, surgical intervention may be needed. Preventing aneurysm rupture or enlargement is the major goal of therapy.
Causes
An abdominal aortic aneurysm may be caused by multiple factors that result in the weakening of the aortic vessel wall. Atherosclerosis, or build-up of plaque within the vessel wall, is thought to play an important role in aneurysmal disease. Other risk factors associated with atherosclerosis may include: age (greater than 60), cigarette smoking, male gender (occurrence in males is five times greater than that of females), family history, hyperlipidemia (high fat content in the blood), hypertension (high blood pressure), or diabetes.
Symptoms
About three out of every four patients with abdominal aortic aneurysms do not have symptoms. Their aortic aneurysm may be discovered incidentally by X-ray, computed tomography scan (CT scan), or magnetic resonance imaging (MRI) that is being done for other conditions. Since abdominal aneurysm may be present without symptoms, it is referred to as the "silent killer" because it may rupture before being diagnosed.
Pain is the most common symptom of an abdominal aortic aneurysm. The pain may be located in the abdomen, chest, lower back, or groin area. The pain may be severe or dull, and is often associated with the imminent rupture of the aneurysm. Acute, sudden onset of severe pain in the back and/or abdomen may represent rupture and is a life threatening medical emergency. Abdominal aortic aneurysms may also cause a pulsing sensation, similar to a heartbeat, in the abdomen.
Diagnosis
In addition to a complete medical history and physical examination, diagnostic procedures for an aneurysm may include any, or a combination, of the following:
Computed tomography scan (Also called a CT scan) - This is a imaging study that uses a combination of x-rays and computer technology to produce cross-sectional pictures, both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
Magnetic resonance imaging (MRI) - This is a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
Ultrasound - This study uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
Arteriogram or angiogram - This is an x-ray imaging study of the blood vessels which utilizes contrast to evaluate blood vessel flow pattern. A dye, or contrast, will be injected through a thin flexible tube placed in an artery. This dye makes the blood vessels visible on x-ray.
Treatments
Potential treatment for an aortic aneurysm may include the following options:
Watchful waiting - A small aneurysm or one that does not cause symptoms may not require surgical treatment until it reaches a certain size or is rapidly increasing in size over a short period of time. Your doctor may recommend "watchful waiting." This may include an ultrasound, ultrasound, or CT scan every six months to closely monitor the aneurysm.
Surgery - This treatment requires an abdominal incision so the aortic aneurysm can be repaired surgically. A specialized cylinder-like tube called a graft is used to repair the aneurysm. This graft is sewn to the aorta, connecting one end of the aorta at the site of the aneurysm to the other end.
Endovascular aortic aneurysm repair (or EVAR) - This is a procedure that requires only small catheter placement in the groin along with the use of x-ray guidance and specially-designed instruments to repair the aneurysm. A special device is inserted through the groin catheter which seal the aortic aneurysm from inside. The patient usually goes home the next day following this treatment. There is no abdominal incision or groin incision in this minimally-invasive treatment.