Aortic dissection

Answer 1

Definition

Aortic dissection is a potentially life-threatening condition in which there is 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 occurs because of a tear or damage to the inner wall of the aorta.

This usually occurs in the thoracic (chest) portion of the artery, but may also occur in the abdominal portion.

An aortic dissection is classified as type A or B depending on where it begins and ends.

• Type A begins in the first (ascending) part of the aorta.
• Type B begins in the descending part of the aorta.

When a tear occurs, it creates two channels: One in which blood continues to travel and another where blood remains still. As the aortic dissection grows bigger, the channel with nontraveling blood can get bigger and push on other branches of the aorta.

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

The exact cause is unknown, but risks include atherosclerosis (hardening of the arteries) and high blood pressure. Traumatic injury is a major cause of aortic dissection, especially blunt trauma to the chest. Hitting the steering wheel of a car during an accident is a common traumatic cause.

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

• Aging
• Bicuspid aortic valve
• Coarctation (narrowing) of the aorta
• Connective tissue disorders
• Ehlers-Danlos syndrome
• Heart surgery or procedures
• Marfan syndrome
• Pregnancy
• Pseudoxanthoma elasticum
• Vascular inflammation due to conditions such as arteritis and syphilis

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

Symptoms

The symptoms usually begin suddenly, and include severe chest pain. The pain may:

• Be described as sharp, stabbing, tearing, or ripping
• Be felt below the chest bone, then moves 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

Other symptoms may include:

• Changes in thought ability, confusion, disorientation
• Decreased movement in any part of the body
• Decreased sensation in any part of the body
• Dizziness
• Dry mouth
• Dry skin
• Fainting
• Nausea and vomiting
• Pallor
• Profuse sweating (clammy skin)
• Rapid, weak pulse
• Shortness of breath -- difficulty breathing when lying flat (orthopnea)

Signs and tests

The health care provider will take your family history and listen to your heart, lungs, and abdomen with a stethoscope. A "blowing" murmur over the aorta, a heart murmur, or other abnormal sound may be heard.

There may be a difference in blood pressure between the right and left arms, or between the arms and the legs.

There may be low blood pressure, bulging neck veins, or signs resembling a heart attack. There may be signs of shock, but with normal blood pressure.

Aortic dissection or aortic aneurysm may be seen on:

• Aortic angiography
• Chest x-ray -- may show chest widening or fluid in the lining of the lung (pleural effusion)
• Chest MRI
• CT scan of chest with dye
• Doppler ultrasonography (occasionally performed)
• Echocardiogram
• Transesophageal echocardiogram (TEE)

Treatment

The goal of treatment is to prevent complications. Hospitalization is required.

Type A aortic dissections require immediate surgery to repair the aorta. Type B aortic dissections may be treated with medication first.

Drugs that lower blood pressure may be prescribed. These drugs may be given through a vein (intravenously). Strong pain relievers are usually needed. Heart medications such as beta-blockers may reduce some of the symptoms.

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

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 ruptured aorta survive.

Complications

• Aortic rupture causing rapid blood loss, shock
• Bleeding from the aorta
• Blood clots
• Cardiac tamponade
• Heart attack
• Not enough blood flow past the dissection
• Permanent kidney failure
• Stroke

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 atherosclerosis (hardening of the arteries) and high blood pressure may reduce your risk of aortic dissection. Tight control of blood pressure in patients at risk of dissection is very important. Drugs such as angiotensin receptor blockers, ACE inhibitors, and beta-blockers may reduce the likelihood of dissection.

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

Many cases of aortic dissection cannot be prevented.

References

Poonyagariyagorn H, Hook M, Bhatt DL. Cardiovascular emergencies. In: Cleveland Clinic: Current Clinical Medicine 2009. 1st ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 14.

Ankel F. Aortic dissection. In: Marx JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier;2009:chap 83.

Reviewed By

Review Date: 05/04/2010

Issam Mikati, MD, Associate Professor of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL. Review provided byVeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.