The aorta is the largest artery (blood vessel) in the body and carries oxygen-rich blood away from the heart to all parts of the body. Aortic dissection is a serious condition in which there is a tear in the wall of the aorta. Blood may flow in between the layers of the blood vessel wall (dissection) as the tear extends which can lead to aortic rupture or decreased blood flow to the organs. There are two types of aortic dissections:
- Type A which is the more common and dangerous of the two and involves a tear in the part of the aorta where it exits the heart or a tear in the upper, or ascending aorta, which may extend into the abdomen.
- Type B which involves a tear in the lower, or descending, aorta only, which may also extend into the abdomen.
When a tear occurs, it creates two channels, one in which blood continues to travel, and another where blood stays still. If the channel with non-traveling blood gets larger, it can push on other branches of the aorta which can narrow the branches and reduce blood flow through them. Aortic dissection may decrease or stop the blood flow to many different parts of the body. Patients may experience short-term or long-term problems or damage to the brain, heart, intestines or bowels, kidneys, or legs.
The exact cause of aortic dissection is unknown, but more common risk factors include:
- High blood pressure (hypertension)
- Atherosclerosis, or hardening of the arteries
- Bicuspid aortic valve
- Coarctation (narrowing) of the aorta
Other risk factors and conditions linked to aortic dissection include:
- Genetic diseases such as Marfan, Turner’s or Ehlers-Danlos syndrome
- Swelling of the blood vessels due to conditions such as arteritis and syphilis
- Cocaine use
- High-intensity weightlifting
Many cases of aortic dissection cannot be prevented, but there are steps individuals can take to reduce their risk including:
- Treating and controlling atherosclerosis
- Keeping high blood pressure under control, especially if you are at risk for dissection
- Taking safety precautions to prevent injuries that can cause dissections
- Making sure to follow up regularly with their physician if they have been diagnosed with Marfan or Ehlers-Danlos syndrome
In most cases, the symptoms begin suddenly and can be similar to other heart problems such as a heart attack. Typical signs and symptoms include sudden severe chest pain often described as sharp, stabbing, tearing or ripping, felt below the chest bone that moves under the shoulder blades or to the back. The pain may also move to the shoulder, neck, arm, jaw, abdomen or hips and can change positions, often moving to the arms and legs as the aortic dissection worsens. Other symptoms may include: Fainting or dizziness Clammy and or pale skin Nausea and vomiting Rapid, weak pulse Shortness of breath and trouble breathing when lying flat Pain in the abdomen Stroke symptoms Swallowing difficulties from pressure on the esophagus If you have symptoms of an aortic dissection or severe chest pain, call 9-1-1 or your local emergency number, or go to the emergency room as quickly as possible.
An aortic dissection may be suspected when a physician examining a patient observes a "blowing" murmur over the aorta, heart murmur, or other abnormal sound; a difference in blood pressure from one arm to the other or between the arms and the legs; low blood pressure; signs resembling a heart attack; signs of shock, but with normal blood pressure. If a physician suspects a patient is suffering from an aortic dissection, specialized tests will be used to confirm it. Tests may include: CT aortic angiography Chest x-ray Chest MRI CT scan of the chest with or without dye Echocardiogram Transesophageal echocardiogram (TEE) The physician will also order blood work to rule out a heart attack.
Aortic dissection is a life-threatening condition and needs to be treated right away. Surgery is necessary for most Type A dissections, but medications such as beta blockers and nitroprusside may be prescribed to reduce the heart rate and lower blood pressure to prevent aortic dissection from worsening in an effort to stabilize blood pressure prior to surgery. Type B dissections may be treated with surgery or with the same medications used for those with type A without surgery. There are two surgical techniques used:
- Open chest or abdominal surgery requiring an incision made in the chest or abdomen.
- Endovascular surgery to repair the aorta which is performed without major surgical incisions using thoracic stent-grafts inserted through the femoral artery in the groin.
For patients with type A dissection, 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 synthetic tube (graft). If the aortic valve leaks as a result of the damaged aorta, it may be replaced at the same time. The new valve is placed within the graft used to reconstruct the aorta. When blood pressure and pain cannot be controlled with medications or in the event that other complications associated with Type B aortic dissection occur, thoracic stents may be placed in the aorta to repair complicated type B aortic dissections. Patients who have been treated for aortic dissection will need lifelong treatment for high blood pressure. They will also need follow up CT scans every few months to monitor the aorta.