The aorta is a large artery that carries blood out of your heart. If you experience a dissection of the aorta, it means that blood has entered the wall of the artery, between the inner and middle layers. This can happen if the inner layer of your aorta tears, allowing blood to pass from the main body of the artery into the wall.
Sometimes, blood hemorrhages from the tiny vessels that supply the outside wall of your aorta. This can also lead to blood accumulating inside the layers of the aortic wall.
The danger is that the dissection could channel blood out of your aorta, causing a fatal rupture of the artery. Serious complications can arise if the dissection channels blood into the space around your heart or lungs. If you have severe chest pain or other symptoms of an aortic dissection, call 911 immediately.
Types of Dissections of the Aorta
Aortic dissections are classified as Type A or Type B. The aorta travels in an upward direction when it first leaves your heart. This is called the ascending aorta. It then arches downward, passing from your chest into your abdomen. This is known as the descending aorta.
A dissection can occur in the ascending or descending part of your aorta, but most are found in the ascending section, where they are classified as Type A.
Dissections in the descending aorta are classified as Type B. They tend to be less life-threatening than Type A and require less urgent treatment.
Causes of Dissections of the Aorta
Although the exact cause of aortic dissections is unknown, doctors believe that high blood pressure is a contributing factor because it causes strain on the walls of your arteries.
Anything that weakens your aortic wall can cause a dissection, including inherited conditions in which your body tissues develop abnormally, such as Marfan syndrome, or accidental injuries to the chest.
Who Is at Risk for Dissections of the Aorta?
Your risk of a dissection increases with age and is especially high if you are a male between 40 and 70 years old.
The following factors can also increase your risk:
- high blood pressure, which is present in more than 80 percent of cases
- atherosclerosis (hardening of your arteries)
- conditions such as Marfan syndrome, in which your body’s tissues are weaker than normal
- surgical procedures carried out near the heart
- motor vehicle accidents involving chest injuries
- a narrowed aorta, or one with a faulty valve
- cocaine use (as it can cause abnormalities in your circulation)
The Symptoms of Dissections of the Aorta
The symptoms of an aortic dissection can be difficult to distinguish from those of other heart conditions, such as a heart attack. Symptoms may include:
Chest pain is the most common symptom of this condition. There is typically severe pain, coupled with a feeling that something is tearing in your chest. Unlike in the case of a heart attack, the pain usually begins suddenly, rather than slowly building to a peak, and it seems to move around.
Some people experience milder pain, which is sometimes mistaken for muscle strain, but this is less common.
- weakness or paralysis on one side of your body
- trouble speaking
- a weaker pulse in one arm than in the other
- dizziness or confusion
How Are Dissections of the Aorta Diagnosed?
Your doctor will examine you and use a stethoscope to listen for abnormal noises coming from your aorta. When the doctor takes your blood pressure, the reading may be different in one arm than in the other.
A test called an ECG (electrocardiogram) may be needed to see if you are having a heart attack. Sometimes an aortic dissection can be mistaken for a heart attack, and sometimes you can have both conditions at the same time.
You may also need to have imaging scans done. These can include a chest X-ray, a CT (computed tomography) scan, and an MRI (magnetic resonance imaging) scan. You might also have an echocardiogram. This involves passing a device that emits sound waves down your throat, until it is close to the area of your heart. The sound waves are used to create an image of your heart and aorta.
Treating Dissections of the Aorta
Type B dissection can often be treated with medication, while Type A normally requires surgery.
You will receive drugs to relieve your pain (usually morphine), and medication to lower your blood pressure (usually beta-blockers).
The torn section of your aorta is removed and replaced with a synthetic graft. If one of your heart valves has been damaged, this will also be replaced.
You may also need surgery if your Type B dissection continues to worsen even when your blood pressure is under control.
Long-Term Outlook for Dissections of the Aorta
If you have a Type A dissection, emergency surgery before the aorta ruptures gives you a good chance of surviving and recovering. Once your aorta has ruptured your chances of survival are only 50 percent—so early detection is essential. A Type B dissection is usually manageable in the long term with medication and careful monitoring.
If you have a condition that increases your risk of aortic dissection, such as atherosclerosis, it is important that your doctor monitor the width of your aorta every year. If your aorta grows beyond a certain width, you may need to have the abnormal section replaced to prevent a dissection.