Aortic dissection is a potentially life-threatening condition in which there is bleeding into and along the wall of the aorta, the major artery leaving the heart.

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

The aorta has different branches through which blood flows. 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 and typically moves to another part of the chest. Type B begins in the last (descending) part of the aorta and moves down the abdomen.

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 non-traveling 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 as can be caused by hitting the steering wheel of a car during an accident.

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

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

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.

• Chest pain
  • Sudden, severe, sharp, stabbing, tearing, or ripping
  • Located below the chest bone, then moves under the shoulder blades or to the back
  • May move to shoulder, neck, arm, jaw, abdomen, or hips
  • Location may change -- pain typically moves to the arms and legs as the aortic dissection gets worse
• Changes in thought ability, confusion, disorientation
• Decreased movement, any location
• Decreased sensation, any location
• Intense anxiety, anguish
• Pallor
• Rapid, weak pulse
• Profuse sweating  (clammy skin)
• Dry skin
• Dry mouth  
• Thirst
• Nausea and vomiting
• Dizziness  
• Fainting
• Shortness of breath -- difficulty breathing when lying flat (orthopnea)

The symptoms usually begin suddenly.

The health care provider will 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 (inadequate blood flow to the body tissues), but with normal blood pressure.

Aortic dissection or aortic aneurysm may be revealed on:

• Echocardiogram
• Transesophageal echocardiogram (TEE)
• 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
• Aortic angiography
• Doppler ultrasonography (occasionally performed)