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An aortic dissection is a serious condition in which a tear develops in the inner layer of the aorta, the large blood vessel branching off of the heart. Blood surges through this tear into the middle layer of the aorta, causing the inner and middle layers to separate (dissect). If the blood-filled channel ruptures through the outside aortic wall, aortic dissection is usually fatal.

Aortic dissection, also called dissecting aneurysm, is relatively uncommon. Anyone can develop the condition, but it most frequently occurs in men and women in their 60s and 70s. Men are twice as likely to be affected by aortic dissection as women are. The signs and symptoms of aortic dissection may mimic those of other diseases, so it is not always diagnosed until after complications occur. However, when an aortic dissection is detected early and treated promptly, your chance of survival greatly improves.

The symptoms of an aortic dissection may be similar to those of other heart problems, such as a heart attack. Typical signs and symptoms include:

• Sudden severe chest or upper back pain, often described as a tearing, ripping or shearing sensation, that radiates down the back
• Loss of consciousness (fainting)
• Shortness of breath
• Weakness

An aortic dissection arises in a weakened area of the aortic wall. Chronic high blood pressure may stress the aortic tissue, making it more susceptible to tearing. You can also inherit a condition associated with a weakened and enlarged aorta, such as Marfan syndrome. Rarely, aortic dissections may be caused by traumatic injury to the chest area, such as during motor vehicle accidents.

Aortic dissections are divided into two groups depending on which part of the aorta is affected:

• Type A. This is the more common and dangerous type of aortic dissection. It involves a tear in the ascending portion of the aorta just where it exits the heart or a tear extending from the ascending portion down to the descending portion of the aorta, which may extend into the abdomen.
• Type B. This type involves a tear in the descending aorta only, which also may extend into the abdomen.

The strongest risk factor for aortic dissection is uncontrolled high blood pressure (hypertension), which is observed in at least two-thirds of all cases. Other cardiovascular risk factors include:

• Atherosclerosis (hardening of the arteries)
• Pre-existing aortic aneurysm (weakened and bulging artery)
• Bicuspid aortic valve (a defective aortic valve)
• Aortic coarctation (constriction of the aorta)

People with certain genetic diseases are more likely to have an aortic dissection than people in the general population. These include:

• Turner syndrome. People with this syndrome have 45 chromosomes, including one missing or incomplete X chromosome, instead of 46. High blood pressure, heart problems and a number of other health conditions may result from this disorder.
• Marfan syndrome. This is a condition in which connective tissue, which supports various structures in the body, is weak. People with this disorder tend to have weak heart valves and blood vessels that break easily.
• Ehlers-Danlos syndrome. This group of connective tissue disorders is characterized by skin that bruises or tears easily, loose joints and fragile blood vessels.

Cocaine use has also been implicated as a risk factor for aortic dissection, most likely because the drug temporarily raises blood pressure. Infrequently, aortic dissections occur in otherwise healthy women during the third trimester of pregnancy.

If you have symptoms such as severe chest pain, fainting or sudden onset of shortness of breath, contact your doctor or call for emergency medical assistance. While experiencing such symptoms doesn't necessarily mean that you have a serious problem, it's best to get checked out quickly. Early detection and treatment may help save your life.

Detecting an aortic dissection can be tricky because the symptoms are similar to those of a variety of health problems. Doctors often suspect an aortic dissection if the following signs and symptoms are present:

• Sudden tearing or ripping chest pain
• Widening of the aorta on chest x-ray
• Blood pressure difference between right and left arms

Although this combination is useful for diagnosing aortic dissections quickly, most diagnoses are confirmed by more sensitive imaging techniques. The most frequently used imaging procedures include:

• Computerized tomography (CT) scan. CT scanning uses a machine that generates X-rays to produce cross-sectional images of the body. In order to diagnose an aortic dissection, a CT scan of the chest is taken. A dye that contains iodine called contrast is often injected into the blood during a CT scan. Contrast makes the heart, aorta and other blood vessels more visible on the CT pictures.
• Magnetic resonance imaging (MRI). An MRI scan is a test that uses a magnetic field and pulses of radio wave energy to make pictures of the body. An MRI of the chest can reveal problems with the heart and blood vessels. As with the CT scan, contrast material may be injected into a vein to enhance the pictures.
• Transesophageal echocardiography (TEE). An echocardiogram is a type of test that uses high-pitched sound waves to produce an image of the heart. A TEE is a special type of echocardiogram in which an ultrasound probe is inserted through the esophagus. Since the ultrasound probe is placed close to the heart and the aorta, it provides a clearer picture of your heart and its structures than would a regular echocardiogram.

Fatal complications may arise from an untreated aortic dissection. The most common cause of death is rupture of an aortic dissection into one of the body cavities, which causes severe internal bleeding. Sometimes an aortic dissection runs down the length of the aorta and affects the arteries that branch off of the aorta. If an aortic dissection interferes with blood flow from these vessels to the rest of the body, tissue damage such as stroke or paralysis may occur.

An aortic dissection is a medical emergency requiring immediate treatment. Therapy may include surgery or medications, depending on the area of the aorta involved.

Surgery is the preferred treatment for type A and severe type B aortic dissections. During the surgical procedure, surgeons remove as much of the dissected aorta as possible, block the entry of blood into the aortic wall and reconstruct the aorta with a metal or plastic tube called a graft.

Aortic dissections are also treated with medications, such as beta-blockers and sodium nitroprusside, to relieve the force of blood on the aortic wall by reducing the heart rate and lowering blood pressure. With reduced blood force, the aortic dissection is less likely to worsen. These medications may be used to prepare a patient for surgery. Most people with type B dissections can be treated with medications alone.

After treatment many people with aortic dissections need to take blood pressure lowering medication for the rest of their lives. In addition, they'll need a follow-up CT or MRI every six to 12 months to monitor their condition.

The prognosis for aortic dissection has greatly improved in recent years. With treatment and regular follow-up, the majority of people with this condition can expect to live at least 10 years after diagnosis.

The most important way to help prevent an aortic dissection is to keep your blood pressure under control. Here are a few tips to reduce your risk:

• Control your blood pressure. If you have high blood pressure, get a home blood pressure-measuring device to help you monitor and keep your blood pressure well controlled.
• Don't smoke. Or, if you do, take steps to stop.
• Maintain an ideal weight. Follow a low-salt diet and exercise regularly.
• Watch your cholesterol. Keep your cholesterol levels within a range that is recommended by your doctor.
• Wear a seat belt. This reduces the risk of injury to your chest area.
• Keep your doctor well-informed. If you have a family history of aortic dissection, talk to your doctor.

If you have a genetic condition that increases your risk of aortic dissection, your doctor may recommend medications, even if your blood pressure is normal. Talk to your doctor about which method or combination of methods is best for you.