What Is an Aneurysm?
From National Institute of Health www.nhlbi.nih.gov
An aneurysm (AN-u-rism) is a balloon-like bulge in an artery. Arteries are blood vessels that carry oxygen-rich blood to your body.
Arteries have thick walls to withstand normal blood pressure. However, certain medical problems, genetic conditions, and trauma can damage or injure artery walls. The force of blood pushing against the weakened or injured walls can cause an aneurysm.
An aneurysm can grow large and rupture (burst) or dissect. A rupture causes dangerous bleeding inside the body. A dissection is a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall.
Both rupture and dissection often are fatal.
Overview
Most aneurysms occur in the aorta, the main artery that carries oxygen-rich blood from the heart to the body. The aorta goes through the chest and abdomen.
An aneurysm that occurs in the chest portion of the aorta is called a thoracic (tho-RAS-ik) aortic aneurysm. An aneurysm that occurs in the abdominal portion of the aorta is called an abdominal aortic aneurysm.
Aneurysms also can occur in other arteries, but these types of aneurysm are less common. This article focuses on aortic aneurysms.
About 13,000 Americans die each year from aortic aneurysms. Most of the deaths result from rupture or dissection.
Early diagnosis and treatment can help prevent rupture and dissection. However, aneurysms can develop and grow large before causing any symptoms. Thus, people who are at high risk for aneurysms can benefit from early, routine screening.
Outlook
Doctors often can successfully treat aortic aneurysms with medicines or surgery if they’re found in time. Medicines may be given to lower blood pressure, relax blood vessels, and reduce the risk of rupture.
Large aortic aneurysms often can be repaired with surgery. During surgery, the weak or damaged portion of the aorta is replaced or reinforced.
What Causes an Aneurysm?
The force of blood pushing against the walls of an artery combined with damage or injury to the artery’s walls can cause an aneurysm.
Many conditions and factors can damage and weaken the walls of the aorta and cause aortic aneurysms. Examples include aging, smoking, high blood pressure, and atherosclerosis (ath-er-o-skler-O-sis). Atherosclerosis is the hardening and narrowing of the arteries due to the buildup of a waxy substance called plaque (plak).
Rarely, infections—such as untreated syphilis (a sexually transmitted infection)—can cause aortic aneurysms. Aortic aneurysms also can occur as a result of diseases that inflame the blood vessels, such as vasculitis (vas-kyu-LI-tis).
A family history of aneurysms also may play a role in causing aortic aneurysms.
In addition to the factors above, certain genetic conditions may cause thoracic aortic aneurysms (TAAs). Examples of these conditions include Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome (the vascular type), and Turner syndrome.
These genetic conditions can weaken the body’s connective tissues and damage the aorta. People who have these conditions tend to develop aneurysms at a younger age than other people. They’re also at higher risk for rupture and dissection.
Trauma, such as a car accident, also can damage the walls of the aorta and lead to TAAs.
Researchers continue to look for other causes of aortic aneurysms. For example, they’re looking for genetic mutations (changes in the genes) that may contribute to or cause aneurysms.
Who Is at Risk for an Aneurysm?
Certain factors put you at higher risk for an aortic aneurysm. These factors include:
- Male gender. Men are more likely than women to have aortic aneurysms.
- Age. The risk for abdominal aortic aneurysms increases as you get older. These aneurysms are more likely to occur in people who are aged 65 or older.
- Smoking. Smoking can damage and weaken the walls of the aorta.
- A family history of aortic aneurysms. People who have family histories of aortic aneurysms are at higher risk for the condition, and they may have aneurysms before the age of 65.
- A history of aneurysms in the arteries of the legs.
- Certain diseases and conditions that weaken the walls of the aorta. Examples include high blood pressure and atherosclerosis.
Having a bicuspid aortic valve can raise the risk of having a thoracic aortic aneurysm. A bicuspid aortic valve has two leaflets instead of the typical three.
Car accidents or trauma also can injure the arteries and increase the risk for aneurysms.
How Is an Aneurysm Diagnosed?
If you have an aortic aneurysm but no symptoms, your doctor may find it by chance during a routine physical exam. More often, doctors find aneurysms during tests done for other reasons, such as chest or abdominal pain.
If you have an abdominal aortic aneurysm (AAA), your doctor may feel a throbbing mass in your abdomen. A rapidly growing aneurysm about to rupture (burst) can be tender and very painful when pressed. If you're overweight or obese, it may be hard for your doctor to feel even a large AAA.
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
Ultrasound and Echocardiography
Ultrasound and echocardiography (echo) are simple, painless tests that use sound waves to create pictures of the structures inside your body. These tests can show the size of an aortic aneurysm, if one is found.
Computed Tomography Scan
A computed tomography scan, or CT scan, is a painless test that uses x rays to take clear, detailed pictures of your organs.
During the test, your doctor will inject dye into a vein in your arm. The dye makes your arteries, including your aorta, visible on the CT scan pictures.
Your doctor may recommend this test if he or she thinks you have an AAA or a thoracic aortic aneurysm (TAA). A CT scan can show the size and shape of an aneurysm. This test provides more detailed pictures than an ultrasound or echo.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) uses magnets and radio waves to create pictures of the organs and structures in your body. This test works well for detecting aneurysms and pinpointing their size and exact location.
Angiography
Angiography (an-jee-OG-ra-fee) is a test that uses dye and special x rays to show the insides of your arteries. This test shows the amount of damage and blockage in blood vessels.
Aortic angiography shows the inside of your aorta. The test may show the location and size of an aortic aneurysm.
How Is an Aneurysm Treated?
Aortic aneurysms are treated with medicines and surgery. Small aneurysms that are found early and aren’t causing symptoms may not need treatment. Other aneurysms need to be treated.
The goals of treatment may include:
- Preventing the aneurysm from growing
- Preventing or reversing damage to other body structures
- Preventing or treating a rupture or dissection
- Allowing you to continue doing your normal daily activities
Treatment for an aortic aneurysm is based on its size. Your doctor may recommend routine testing to make sure an aneurysm isn't getting bigger. This method usually is used for aneurysms that are smaller than 5 centimeters (about 2 inches) across.
How often you need testing (for example, every few months or every year) is based on the size of the aneurysm and how fast it's growing. The larger it is and the faster it's growing, the more often you may need to be checked.
Medicines
If you have an aortic aneurysm, your doctor may prescribe medicines before surgery or instead of surgery. Medicines are used to lower blood pressure, relax blood vessels, and lower the risk that the aneurysm will rupture (burst). Beta blockers and calcium channel blockers are the medicines most commonly used.
Surgery
Your doctor may recommend surgery if your aneurysm is growing quickly or is at risk of rupture or dissection.
The two main types of surgery to repair aortic aneurysms are open abdominal or open chest repair and endovascular repair.
Open Abdominal or Open Chest Repair
The standard and most common type of surgery for aortic aneurysms is open abdominal or open chest repair. This surgery involves a major incision (cut) in the abdomen or chest.
General anesthesia (AN-es-THE-ze-ah) is used during this procedure. The term “anesthesia” refers to a loss of feeling and awareness. General anesthesia temporarily puts you to sleep.
During the surgery, the aneurysm is removed. Then, the section of aorta is replaced with a graft made of material such as Dacron® or Teflon.® The surgery takes 3 to 6 hours; you’ll remain in the hospital for 5 to 8 days.
If needed, repair of the aortic heart valve also may be done during open abdominal or open chest surgery.
It often takes a month to recover from open abdominal or open chest surgery and return to full activity. Most patients make a full recovery.
Endovascular Repair
In endovascular repair, the aneurysm isn't removed. Instead, a graft is inserted into the aorta to strengthen it. Surgeons do this type of surgery using catheters (tubes) inserted into the arteries; it doesn't require surgically opening the chest or abdomen. General anesthesia is used during this procedure.
The surgeon first inserts a catheter into an artery in the groin (upper thigh) and threads it to the aneurysm. Then, using an x ray to see the artery, 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. This helps prevent the aneurysm from rupturing.