Abdominal Aortic Aneurysm
What Is It?
An aneurysm (AN-u-rism) is an abnormal bulge or "ballooning" in the wall of an artery. An aneurysm that grows and becomes large enough can burst, causing dangerous, often fatal, bleeding inside the body. Most aneurysms occur in the aorta, the main artery that carries blood from the heart to the rest of the body.
- An aneurysm is an abnormal bulge or "ballooning" in the wall of an artery. Arteries are blood vessels that carry oxygen-rich blood from the heart to other parts of the body.
- An aneurysm that grows and becomes large enough can rupture, causing dangerous bleeding inside the body.
- Most aneurysms occur in the aorta. The aorta is the main artery that carries blood from the heart to the rest of the body.
- Most aneurysms (3 out of 4) are found by chance when a diagnostic test, such as x ray or ultrasound, is performed for a different reason.
- Many cases of ruptured aneurysm can be prevented with early diagnosis and medical treatment.
- Because aneurysms can develop and become large before causing any symptoms, it is important to look for them in people who are at the highest risk. Ultrasound screening for abdominal aortic aneurysms is recommended for men who have ever smoked and are between the ages of 65 and 75.
- Medicines and surgery are the two main treatments for aneurysms. Medicines may be prescribed before surgery or instead of surgery.
- To prevent an aneurysm and keep blood vessels healthy, quit smoking, eat a low-fat, low-cholesterol diet, get regular physical activity, and control high blood pressure and high cholesterol.
Most aneurysms occur in the aorta. The aorta is the main artery that carries blood from the heart to the rest of the body. The aorta comes out from the left ventricle (VEN-trih-kul) of the heart and travels through the chest and abdomen. An aneurysm that occurs in the aorta in the chest is called a thoracic (tho-RAS-ik) aortic aneurysm. An aneurysm that occurs in the aorta in the abdomen is called an abdominal aortic aneurysm.
About 15,000 Americans die each year from ruptured aortic aneurysms. Ruptured aortic aneurysm is the 10th leading cause of death in men over age 50 in the United States.
Many cases of ruptured aneurysm can be prevented with early diagnosis and medical treatment. Because aneurysms can develop and become large before causing any symptoms, it is important to look for them in people who are at the highest risk. Experts recommend that men who are 65 to 75 years old and have ever smoked (at least 100 cigarettes in their lifetime) should be checked for abdominal aortic aneurysms.
When found in time, aneurysms can usually be treated successfully with medicines or surgery. If an aortic aneurysm is found, the doctor may prescribe medicine to reduce the heart rate and blood pressure. This can reduce the risk of rupture.
Large aortic aneurysms, if found in time, can often be repaired with surgery to replace the diseased portion of the aorta. The outlook is usually excellent.
Abdominal Aortic Aneurysm
An aortic aneurysm that occurs in the part of the aorta running through the abdomen is an abdominal aortic aneurysm. Three in four aortic aneurysms are AAAs.
An AAA can grow very large without producing symptoms. About 1 in 5 AAAs rupture.
Thoracic Aortic Aneurysm
An aortic aneurysm that occurs in the part of the aorta running through the thorax (chest) is a thoracic aortic aneurysm. One in four aortic aneurysms is a TAA.
Most TAAs do not produce symptoms, even when they are large. Only half of all people with TAAs notice any symptoms. TAAs are identified more often now than in the past because of chest computed tomography (CT) scans performed for other medical problems.
In a common type of TAA, the walls of the aorta become weak and a section nearest to the heart enlarges. Then the valve between the heart and the aorta cannot close properly and blood leaks backward into the heart. Less commonly, a TAA can develop in the upper back away from the heart. A TAA in this location can result from an injury to the chest such as from an auto crash.
What Causes an Aneurysm?
An aneurysm can result from atherosclerosis (hardening and narrowing of the inside of arteries). As atherosclerosis develops, the artery walls become thick and damaged and lose their normal inner lining. This damaged area of artery can stretch or "balloon" from the pressure of blood flow inside the artery, resulting in an aneurysm. An aneurysm also can develop from constant high blood pressure inside an artery.
In rare cases, infections such as untreated syphilis (a sexually transmitted infection) can cause aortic aneurysms. Aortic aneurysms also can occur as a result of diseases that cause inflammation of blood vessels, such as vasculitis.
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Who Is At Risk for an Aneurysm?
Men are 5 to 10 times more likely than women to have an abdominal aortic aneurysm (AAA)-the most common type of aneurysm.
The risk of AAA increases as you get older, and it is more likely to occur in people between the ages of 60 to 80. A peripheral aneurysm also is more likely to affect people ages 60 to 80. Cerebral (brain) aneurysms, though rare, are more likely to occur in people ages 35 to 60.
Factors that increase your risk for aneurysm include:
- Atherosclerosis, a buildup of fatty deposits in the arteries.
- Smoking. You are eight times more likely to develop an aneurysm if you smoke.
- Overweight or obesity.
- A family history of aortic aneurysm, heart disease, or other diseases of the arteries.
- Certain diseases that can weaken the wall of the aorta, such as:
- Marfan syndrome (an inherited disease in which tissues don't develop normally)
- Untreated syphilis (a very rare cause today)
- Tuberculosis (also a very rare cause today)
- Trauma such as a blow to the chest in a car accident.
- Severe and persistent high blood pressure between the ages of 35 and 60.
- Use of stimulant drugs such as cocaine.
What Are the Signs and Symptoms of an Aneurysm?
The signs and symptoms of an aneurysm depend on its type, location, and whether it has ruptured or is interfering with other structures in the body. Aneurysms can develop and grow for years without causing any signs or symptoms. It is often not until an aneurysm ruptures or grows large enough to press on nearby parts of the body or block blood flow that it produces any signs or symptoms.
Abdominal Aortic Aneurysm
Most abdominal aortic aneurysms (AAAs) develop slowly over years and have no signs or symptoms until (or if) they rupture. Sometimes, a doctor can feel a pulsating mass while examining a patient's abdomen. When symptoms are present, they can include:
- Deep penetrating pain in your back or the side of your abdomen
Steady gnawing pain in your abdomen that lasts for hours or days at a time
Coldness, numbness, or tingling in your feet due to blocked blood flow in your legs
If an AAA ruptures, symptoms can include sudden, severe pain in your lower abdomen and back; nausea and vomiting; clammy, sweaty skin; lightheadedness; and a rapid heart rate when standing up. Internal bleeding from a ruptured AAA can send you into shock. Shock is a life-threatening condition in which the organs of the body do not get enough blood flow.
Thoracic Aortic Aneurysm
A thoracic (chest) aortic aneurysm may have no symptoms until the aneurysm begins to leak or grow. Signs or symptoms may include:
- Pain in your jaw, neck, upper back (or other part of your back), or chest
- Coughing, hoarseness, or trouble breathing
How Is an Aneurysm Diagnosed?
An aneurysm may be found by chance during a routine physical exam. More often, an aneurysm is found by chance during an x ray, ultrasound, or computed tomography (CT) scan performed for another reason, such as chest or abdominal pain.
If you have an abdominal aortic aneurysm (AAA), the doctor may feel a pulsating mass in your abdomen. A rapidly growing aneurysm about to rupture can be tender and very painful when pressed. If you are overweight or obese, it may be difficult for your doctor to feel even a large abdominal aneurysm.
If you have an AAA, your doctor may hear rushing blood flow instead of the normal whooshing sound when listening to your abdomen with a stethoscope.
Diagnostic Tests and Procedures
To diagnose and evaluate an aneurysm, one or more of the following tests or procedures may be performed:
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- Chest x ray. A chest x ray provides a picture of the organs and structures inside the chest, including the heart, lungs, and blood vessels.
Ultrasound. This simple and painless test uses sound waves to create a picture of the inside of the body. It shows the size of an aneurysm, if one is detected. The ultrasound scan may be repeated every few months to see how quickly an aneurysm is growing.
- CT scan. A CT scan provides computer-generated, x-ray images of the internal organs. A CT scan may be performed if the doctor suspects a TAA or AAA. A liquid dye that can be seen on an x ray is injected into an arm vein to outline the aorta or artery on the CT scan. The CT scan images can be used to determine the size and shape of an abdominal aneurysm more accurately than an ultrasound.
- MRI. MRI uses magnets and radio waves to create images of the inside of the body. It is very accurate in detecting aneurysms and determining their size and exact location.
- Angiography. Angiography also uses a special dye injected into the blood stream to make the insides of arteries show up on x-ray pictures. An angiogram shows the amount of damage and blockage in blood vessels.
- Aortogram. An aortogram is an angiogram of the aorta. It may show the location and size of an aortic aneurysm, and the arteries of the aorta that are involved.
How Is an Aneurysm Treated?
Goals of Treatment
Some aneurysms, mainly small ones that are not causing pain, can be treated with "watchful waiting." Others need to be treated to prevent growth and complications. The goals of treatment are to prevent the aneurysm from growing, prevent or reverse damage to other body structures, prevent or treat a rupture, and to allow you to continue to participate in normal daily activities.
Medicine and surgery are the two types of treatment for an aneurysm. Medicines may be prescribed before surgery or instead of surgery. Medicines are used to reduce pressure, relax blood vessels, and reduce the risk of rupture. Beta blockers and calcium channel blockers are the medicines most commonly used.
Surgery may be recommended if an aneurysm is large and likely to rupture.
Experts recommend that men who have ever smoked (at least 100 cigarettes in their lifetime) and are between the ages of 65 and 75 should have an ultrasound screening to check for abdominal aortic aneurysms.
Treatment recommendations for aortic aneurysms are based on the size of the aneurysm. Small aneurysms found early can be treated with "watchful waiting."
- If the diameter of the aorta is small-less than 3 centimeters (cm)-and there are no symptoms, "watchful waiting" and a follow up screening in 5 to 10 years may be all that is needed, as determined by the doctor.
- If the aorta is between 3 and 4 cm in diameter, the patient should return to the doctor every year for an ultrasound to see if the aneurysm has grown.
- If the aorta is between 4 and 4.5 cm, testing should be repeated every 6 months.
- If the aorta is larger than 5 cm (2 inches around or about the size of a lemon) or growing more than 1 cm per year, surgery should be considered as soon as possible.
- Two main types of surgery to repair aortic aneurysms are open abdominal or open chest repair and endovascular repair.
The traditional and most common type of surgery for aortic aneurysms is open abdominal or open chest repair. It involves a major incision in the abdomen or chest. General anesthesia is needed with this procedure.
The aneurysm is removed and the section of aorta is replaced with an artificial graft made of material such as Dacron® or Teflon®. The surgery takes 3 to 6 hours, and the patient remains in the hospital for 5 to 8 days. It often takes a month to recover from open abdominal or open chest surgery and return to full activity. Open abdominal and chest surgeries have been performed for 50 years. More than 90 percent of patients make a full recovery.
In endovascular repair, the aneurysm is not removed, but a graft is inserted into the aorta to strengthen it. This type of surgery is performed through catheters (tubes) inserted into the arteries; it does not require surgically opening the chest or abdomen.
To perform endovascular repair, the doctor first inserts a catheter into an artery in the groin (upper thigh) and threads it up to the area of the aneurysm. Then, watching on x ray, the surgeon threads the graft (also called a stent graft) into the aorta to the aneurysm. The graft is then expanded inside the aorta and fastened in place to form a stable channel for blood flow. The graft reinforces the weakened section of the aorta to prevent the aneurysm from rupturing.
The illustration shows the placement of an endovascular stent graft in an aortic aneurysm. In figure A, a catheter is inserted into an artery in the groin (upper thigh). It is then threaded up to the abdominal aorta, and the stent graft is released from the catheter. In figure B, the stent graft allows blood to flow through the aneurysm.
Endovascular repair surgery reduces recovery time to a few days and greatly reduces time in the hospital. The procedure has been used since 1999. Not all aortic aneurysms can be repaired with this procedure. The exact location or size of the aneurysm may prevent the stent graft from being safely or reliably positioned inside the aneurysm.
How Can an Aneurysm Be Prevented?
The best way to prevent an aneurysm is to avoid the risk factors that increase the chances of developing one. To do this, you can:
- Quit smoking.
- Eat a low-fat, low-cholesterol diet to reduce the buildup of plaque in the arteries. Plaque is a fatty buildup that narrows the arteries.
- Control high blood pressure (eating a low-salt diet helps).
- Control high cholesterol.
- Get regular physical activity.
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