Topic Overview
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.
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's syndrome or
Ehlers-Danlos syndrome.
What causes aortic dissection, and how can it be prevented?
The key point in prevention of aortic dissection is
managing high blood pressure. Minimizing this and other risk factors for
atherosclerosis greatly reduces the risk of aortic
dissection.
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's
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 of aortic dissection?
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.
- Lack of pulse.
- Swelling.
- Pale
skin.
If you experience these symptoms, you should call 911 or other emergency services immediately.
Do not drive yourself as time is
important and stress and movement should be reduced to a minimum. Do not try to
take pain medicine or heart medicine. Taking aspirin with aortic
dissections can be fatal.
If you witness a person
become unconscious, call 911 or other emergency services and start cardiopulmonary
resuscitation (CPR). The emergency operator can coach you on how to perform
CPR.
How is aortic dissection diagnosed?
Your doctor will
ask you questions about your symptoms, medical history, lifestyle, and family
medical history and do a physical exam. He or she may ask if you
have been hit hard in the chest or been in an automobile accident. Several
specialists may see you.
Physical exam
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.
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.
- An angiogram. This test can help your doctor know what the size of your
dissection is and if you have blood clots or other blood vessel
involvement.
- Computed tomography scanning (CT) and
magnetic resonance imaging (MRI) to help your doctor
know if your dissection is growing.
- A transthoracic
echocardiography and 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:
- Paralysis.
- 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. In rare cases, a procedure or surgery may be needed
if:
- Your aorta has ruptured.
- You have
pain that cannot be controlled.
- Other arteries or organs are damaged.