Aortic dissection

Definition

Aortic dissection is a serious condition in which there is a separation of the aorta walls. The small tear can come larger. It can lead to bleeding into and along the wall of the aorta, the major artery carrying blood out of the heart.

Alternative Names

Aortic aneurysm - dissecting

Causes, incidence, and risk factors

When it leaves the heart, the aorta first moves up through the chest toward the head (the ascending aorta). It then bends or arches, and finally moves down through the chest and abdomen (the descending aorta).

Aortic dissection most often happens because of a tear or damage to the inner wall of the aorta. This usually occurs in the chest (thoracic) part of the artery, but it may also occur in the abdominal part.

When a tear occurs, it creates two channels:

• One in which blood continues to travel
• Another where blood stays still

If the channel with nontraveling blood gets bigger, it can push on other branches of the aorta. This can narrow the other branches and reduce blood flow through them.

An aortic dissection may also cause abnormal widening or ballooning of the aorta (aneurysm).

The exact cause is unknown, but more common risks include:

• Aging
• Atherosclerosis
• Blunt trauma to the chest, such as hitting the steering wheel of a car during an accident
• High blood pressure

Other risk factors and conditions associated with the development of aortic dissection include:

• Bicuspid aortic valve
• Coarctation (narrowing) of the aorta
• Connective tissue disorders
• Heart surgery or procedures
• Marfan syndrome and rare genetic disorders
• Pregnancy
• Swelling of the blood vessels due to conditions such as arteritis and syphilis

Aortic dissection occurs in about 2 out of every 10,000 people. It can affect anyone, but is most often seen in men ages 40 to 70.

Symptoms

The symptoms usually begin suddenly, and include severe chest pain. The pain may feel like a heart attack, and can:

• Be described as sharp, stabbing, tearing, or ripping
• Be felt below the chest bone, then move under the shoulder blades or to the back
• Move to the shoulder, neck, arm, jaw, abdomen, or hips
• Change position -- pain typically moves to the arms and legs as the aortic dissection gets worse

Symptoms are caused by a decrease of blood flowing to the rest of the body, and can include:

• Anxiety and a feeling of doom
• Fainting or dizziness
• Heavy sweating (clammy skin)
• Nausea and vomiting
• Pale skin (pallor)
• Rapid, weak pulse
• Shortness of breath -- trouble breathing when lying flat (orthopnea)

Other symptoms may include:

• Pain in the abdomen
• Stroke symptoms
• Swallowing difficulties from pressure on the esophagus

Signs and tests

The health care provider will take your family history and listen to your heart, lungs, and abdomen with a stethoscope. The examinatinon may find:

• A "blowing" murmur over the aorta, heart murmur, or other abnormal sound
• A difference in blood pressure between the right and left arms, or between the arms and legs
• Low blood pressure
• Signs resembling a heart attack
• Signs of shock, but with normal blood pressure

Aortic dissection or aortic aneurysm may be seen on:

• Aortic angiography
• Chest x-ray
• Chest MRI
• CT scan of chest with dye
• Doppler ultrasonography (occasionally performed)
• Echocardiogram
• Transesophageal echocardiogram (TEE)

Blood work to rule out a heart attack is needed.

Treatment

Aortic dissection is a life-threatening condition and needs to be treated right away.

• Dissections that occur in the part of the aorta that is leaving the heart (ascending) are treated with surgery.
• Dissections that occur in other parts of the aorta (descending) may be managed with surgery or medications.

Two different techniques may be used for surgery:

• Standard, open surgery -- a surgical cut is made in the chest or abdomen
• Endovascuar aortic repair -- surgery is done without any major surgical cut

Drugs that lower blood pressure may be prescribed. These drugs may be given through a vein (intravenously). Beta-blockers are the first drugs of choice. Strong pain relievers are usually needed.

If the aortic valve is damaged, valve replacement is needed. If the heart arteries are involved, a coronary bypass is also performed.

Support Groups

Expectations (prognosis)

Aortic dissection is life threatening. The condition can be managed with surgery if it is done before the aorta ruptures. Less than half of patients with a ruptured aorta survive.

Those who survive will need lifelong, aggressive treatment of high blood pressure. They will need to be followed up with CT scans every few months to monitor the aorta.

Complications

Aortic dissection may decrease or stop the blood flow to many different parts of the body. This may result in short-term or long-term problems, or damage to the:

• Brain
• Heart
• Intestines or bowels
• Kidneys
• Legs

Calling your health care provider

If you have symptoms of aortic dissection or severe chest pain, call 911 or your local emergency number, or go to the emergency room as quickly as possible.

Prevention

Proper treatment and control of hardening of the arteries (atherosclerosis) and high blood pressure may reduce your risk of aortic dissection. It is very important for patients at risk for dissection to tightly control their blood pressure.

Take safety precautions to prevent injuries, which can cause dissections.

Many cases of aortic dissection cannot be prevented.

If you have been diagnosed with Marfan or Ehler syndrome, make sure you regularly follow-up with your doctor.

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References

Isselbacher EM. Diseases of the aorta. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 78.