What is an aortic dissection?
Aortic dissection occurs when a small tear develops in the wall of the aorta. The tear forms a new channel between the inner and outer layers of the aortic wall. This causes bleeding into the channel and can enlarge the tear. Aortic dissection is a life-threatening condition.
What causes it?
Aortic dissection can be caused by atherosclerosis (hardening of the arteries) and high blood pressure, traumatic injury to the chest, such as being hit by the steering wheel of a car during an accident, and conditions that are present at birth, such as Marfan syndrome or Ehlers-Danlos syndrome.
Any one or any combination of the following may cause aortic dissection:
- High blood pressure.
Most patients with an aortic dissection have had high blood pressure for many years. The high blood pressure accelerates the natural processes of tissue aging and damage to the tissue, promoting a weakness of the aortic wall and increasing the risk for a tear.
- Chest injury.
Severe chest injury, such as might occur in an automobile accident, may also cause aortic dissection.
- Diseases of the connective tissue.
Either Marfan syndrome or Ehlers-Danlos syndrome can damage the connective tissue in the middle of the aortic wall. This damage can lead to aortic dissection.
- Other diseases.
Certain diseases increase the risk of an aortic dissection. These include lupus, polycystic kidney disease, Cushing's syndrome, giant cell arteritis
A family history of aortic dissection is also a risk factor.
Pregnancy can also increase the risk of a dissection. This risk is caused by the combination of hormonal effect on the tissue structure (elastin fibers) and additional high blood pressure stress.
Illegal drugs that raise blood pressure, such as cocaine, increase the risk of a dissection.
What are the symptoms?
Pain is the leading symptom of aortic dissection. A person typically has a sudden onset of pain at the moment of dissection. The pain is usually described as ripping or tearing and as the worst pain ever experienced. It is usually in between the shoulders on the back and might radiate to the arms or the neck. Less frequently, the pain can be felt as chest pain. The pain is very difficult to distinguish from that of angina or a heart attack.
Other symptoms may include:
- Numbness and the inability to move the legs.
- Pale skin.
How is it diagnosed?
Your doctor will ask you questions about your symptoms, medical history, lifestyle, and family medical history and do a physical exam. You may also be asked if you have been hit hard in the chest or been in an automobile accident. Several specialists may see you.
Your doctor will listen to your heart sounds with a stethoscope, take your pulse and evaluate your circulation, and evaluate your neurological status (nerve and brain function). As the symptoms of aortic dissection mimic many other conditions, you may need several tests.
If you have an aortic dissection, you may need:
- Blood tests. These tests can give your doctor clues about what is causing your symptoms.
- A chest X-ray.
- Computed tomography scanning (CT) or magnetic resonance imaging (MRI) to help your doctor see the dissection.
- A transthoracic echocardiography or transesophageal echocardiography (TEE) to let your doctor look at blood vessels inside your chest.
- An intravascular ultrasound to get a better look at your blood vessels.
How is aortic dissection treated?
The treatment of aortic dissection depends in part on where the dissection is located:
- Dissections involving the aorta where it goes up from the heart (with or without the arch) are known as type A dissections and are typically treated with surgery.
- Dissections involving the rest of the aorta are known as type B dissections. If there are no complications, type B dissections are typically treated with medicines.
Initial emergency treatment
Treatment for aortic dissection should be started immediately following the diagnosis. The goal of initial emergency treatment is to relieve pain and to reduce the blood pressure on the dissection (reduction of the pulsatile load). This helps prevent additional bleeding and reduces the risk of a rupture.
Typically, you are put immediately in an intensive care unit (ICU) or taken to the operating room. Your doctor will continuously monitor and control your blood pressure, pulse, and heart activity.
Treating type A dissections
Typically, the first line of treatment for type A dissections (dissection of the aorta involving the ascending aorta) is surgery.
The goal of the operation is to prevent death due to bleeding and to reestablish blood flow into the extremities and inner organs (if branches of the aorta are involved in the dissection process).
In this open-heart procedure, your chest is opened and the surgeon removes the part of the aorta where the tear is found. The portion of the aorta removed can be replaced with a man-made graft. Another approach uses a similar graft that is placed inside the aorta. In this approach the ascending aorta is not replaced but internally reinforced.
The surgery cannot be done if you are already suffering from a severe complication in the process of dissection, such as a stroke. In this situation an operation would lead to severe bleeding in the brain.
Possible complications of aortic dissection and its surgery include:
- Kidney (renal) failure.
- Infections in the lung and lung failure.
- Decreased heart function and heart attack.
It is sometimes not possible to use surgery in type A dissections. In this case, the same procedures and medicines outlined in the initial emergency treatment section are used.
Treating type B dissections
Type B dissections are usually treated with medicines. A procedure or surgery may be done for a few reasons. These reasons include rupture of the aorta or damage to other arteries or organs.
How can you prevent it?
You may help prevent an aortic dissection by managing risk factors for atherosclerosis, such as high blood pressure.