Related terms: abdominal aortic aneurysm (AAA), aortic aneurysm, aortic dissection, cardiac tamponade, cerebral aneurysm, ventricular aneurysm
An aneurysm is a balloon-like bulge in an artery. Aneurysms can form in arteries of all sizes. An aneurysm occurs when the pressure of blood passing through part of a weakened artery forces the vessel to bulge outward, forming what you might think of as a blister. Not all aneurysms are life-threatening. But if the bulging stretches the artery too far, this vessel may burst, causing a person to bleed to death. An aneurysm that bleeds into the brain can lead to stroke or death.
Aortic dissection occurs when the layers of the wall of the aorta separate or are torn, allowing blood to flow between those layers and causing them to separate further. When the aortic wall separates, blood cannot flow freely, and the aortic wall may burst.
Where do aneurysms occur?
- In the arteries that supply blood to the brain. This is called a cerebral aneurysm.
- In parts of the aorta. The aorta is the large vessel that carries blood from the heart to other parts of the body. Aortic aneurysms can occur in the area below the stomach (abdominal aneurysm) or in the chest (thoracic aneurysm). An abdominal aortic aneurysm (AAA) is usually located below the kidneys. Aortic dissection can occur in the aorta and its main branches. Aneurysms and dissections are classified depending on where they occur in the aorta. Type A occurs in the ascending aorta, which is the part of the aorta that starts from the lower-left chamber of the heart (the left ventricle) and extends to the bend in the aorta (the aortic arch). Type B occurs in the descending aorta, which is the part of the aorta that starts after the aortic arch and ends in the abdomen.
- In the heart's main pumping chamber (the left ventricle). If a section of the heart wall becomes damaged after a heart attack, scarring occurs and the heart wall grows thinner and weaker. This may cause a ventricular aneurysm to form. The weakened area of aneurysm does not work well, which makes your heart work harder to pump blood to the rest of your body. Ventricular aneurysms may cause shortness of breath, chest pain, or an irregular heart beat (arrhythmia). If a ventricular aneurysm leads to congestive heart failure, left ventricular heart failure, or arrhythmia, your doctor may want you to have surgery.
How do aneurysms happen, and who is at risk?
Any condition that causes the walls of the arteries to weaken can lead to an aneurysm. The following increase the risk of an aneurysm or an aortic dissection:
- Atherosclerosis (a build-up of fatty plaque in the arteries).
- High blood pressure.
- Deep wounds, injuries, or infections of the blood vessels.
- A congenital abnormality (a condition that you are born with).
- An inherited disease such as Marfan syndrome.
- A defective gene. Researchers have found that people who have a defect in one of 3 genes related to aortic aneurysms have a greater chance of an aortic dissection in their lifetime.
How are aneurysms detected?
Aneurysms can be detected by physical exam, on a basic chest or stomach x-ray, or by using ultrasound. The size and location can be found through echocardiography or radiological imaging, such as arteriography, magnetic resonance imaging (MRI), and computed tomography (CT) scanning.
A CT scan gets a number of images that your doctor can look at one by one. New computer technology now lets technicians stack the images on top of each other to get a 3-D image that can be rotated and viewed from any angle. The red arrows in the images above point to a large aneurysm of the abdominal aorta seen from the front (left picture) and the side (right picture).
What are the symptoms?
Symptoms depend on the type and location of the aneurysm and result from the pressure caused by an aneurysm's pressing against nearby organs, nerves, and other blood vessels. For example,
- Aortic aneurysms may cause shortness of breath, a croaky or raspy voice, backache, or pain in your left shoulder or between your shoulder blades.
- Aortic dissection may cause sudden and severe pain, and patients often feel like something is ripping or tearing inside of them. The pain is mainly felt in the chest, but it can spread to the back or between the shoulder blades. Aortic dissection may also cause sudden stomach pain, lower back pain, or flu-like symptoms. If blood leaks from the dissection and builds up in the chest, the blood may enter the pericardial space (the sac that surrounds the heart) and prevent the heart from filling properly. This can lead to a life-threatening condition called cardiac tamponade.
- Abdominal aortic aneurysms may cause pain or tenderness below your stomach, make you less hungry, or give you an upset stomach.
- Cerebral (brain) aneurysms may have no symptoms, although you may have headaches, pain in your neck and face, or trouble seeing and talking.
How are aneurysms treated?
Treatment depends on the size and location of the aneurysm and your overall health. Type A aortic aneurysms in the upper chest (the ascending aorta) are usually operated on right away. Type B aortic aneurysms in the lower chest and the area below your stomach (the descending thoracic and abdominal parts of the aorta) may not be as life-threatening. Aneurysms in these locations are watched regularly. If they become about 5 centimeters (almost 2 inches) in diameter, continue to grow, or begin to cause symptoms, your doctor may want you to have surgery to stop the aneurysm from bursting.
For aortic aneurysms or aneurysms that happen in the vessels that supply blood to your arms, legs, and head (the peripheral vessels), surgery involves replacing the weakened section of the vessel with an artificial tube, called a graft.
For patients with smaller or stable Type B aneurysms in the descending aorta or abdominal parts of the aorta—those farthest from the heart, doctors usually ask patients to come in for regular check-ups so they can follow the growth of the aneurysm. If the aneurysm does not grow much, patients may live with the aneurysm for years. Doctors may also prescribe medicines such as beta blockers that lower blood pressure, to relieve the stress on the aortic walls. Medicines are especially useful for patients where the risk of surgery may be greater than the risk of the aneurysm itself.
For patients with aortic dissection, surgery is usually recommended right away for Type A dissections, which are dissections in the part of the aorta closest to the heart. For Type B dissections, or those farther from the heart, patients will be given medicines (such as beta-blockers to lower blood pressure), and the dissection will be watched closely. But, if the dissection begins to leak blood, cause a blockage, or get bigger, surgery is needed.
Nonsurgical Procedure for Treatment of AAAs
Cardiologists at the Texas Heart Institute were among the first to use a nonsurgical technique to treat high-risk patients with abdominal aortic aneurysms. This technique is useful for patients who cannot have surgery because their overall health would make it too dangerous.
The procedure uses a catheter to insert a device called a stent graft. The stent graft is placed within the artery at the site of the aneurysm. The blood flows through the stent graft, decreasing the pressure on the wall of the weakened artery. This decrease in pressure can prevent the aneurysm from bursting.
Benefits of the procedure include no general anesthesia (you are awake for the procedure), a shorter hospital stay (about 24 hours), a faster recovery, and no large scars.
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