An aortic dissection is a tear in the inner lining of the aorta (the main artery that carries oxygen-rich blood from the heart to the rest of the body), creating a space between the inner and outer layers. If blood leaks into that space, then a variety of potentially fatal conditions could result, including heart attack or stroke.

There are two types of aortic dissections: acute and chronic. Acute aortic dissections involve sudden, severe symptoms and usually requires emergency open-heart surgery. An aortic dissection is classified as chronic if it has been present for at least two weeks, usually without recognizable symptoms. This also usually requires emergency treatment.  

Although aortic dissection remains relatively rare, a number of conditions and diseases may put people at higher risk. The leading risk factors are age and high blood pressure, which occur in more than 70 percent of people who suffer from an aortic dissection. Atherosclerosis (hardening of the arteries) as well as a history of heart disease or aortic disease, also raise the risk of aortic dissection.

An aortic dissection is a tear in the inner lining of the aorta (the main artery that carries oxygen-rich blood from the heart to the rest of the body), creating a space between the inner and outer layers. If blood leaks into that space between the layers, it could cause potentially fatal conditions or events such as:

When accompanied by a widening or ballooning part of the wall of the aorta (aortic aneurysm), the condition is referred to as a dissecting aortic aneurysm.

Dissections can be either ascending or descending depending on whether the vessel damage occurred in the part of the aorta that rises up from the heart (a type A dissection) or the part that descends down through the chest (a type B dissection). While both are serious, the ascending aortic dissection is considered the more dangerous of the two and usually requires emergency surgery. Descending aortic dissections are more common and can usually be treated with medical therapy.

The incidence of an aortic dissection is estimated to occur in 2 to 4 per 100,000 person-years, and roughly 2,000 new cases of aortic dissections are reported each year in the United States. However, the condition may be underreported because it is difficult to determine whether death was caused by an aortic dissection, a heart attack or sudden cardiac death without an autopsy.

When untreated, an acute aortic dissection is fatal to more than a third of patients within 24 hours, half of patients within 48 hours and three-quarters of patients within two weeks of onset.

Age plays an important part in the causes of aortic dissection. Among older people, aortic dissection is much more likely to be associated with other forms of heart disease, such as high blood pressure or atherosclerosis. High blood pressure occurs when the blood pushes against the arterial wall with too much force, while atherosclerosis is a disease characterized by plaque deposits that form in the arteries, resulting in narrowed, stiffened arteries. Among younger people, these are rare causes of aortic dissection (less than 35 percent of total cases). Other possible factors that may cause and/or precipitate aortic dissection, especially among younger people include:

• Existing aortic aneurysm. This occurs when a part of the aorta wall weakens and bulges out.
  
  
• Aortic stenosis. A congenital or acquired condition in which the blood flow from the heart to the aorta is reduced by a narrowed (stenotic) aortic valve, which rests between the left ventricle and the aorta. The valve leaflets may be fused or narrowed, or the valve itself may be too small. Bicuspid aortic valve is a congenital anomaly that may be associated with aortic stenosis and dissection.
  
  
• Coarctation of the aorta. A congenital condition in which the aorta is pinched, constricted or narrowed at some point along its length.
  
  
• Valvular regurgitation. A condition in which one or more of the heart’s four valves do not close properly, allowing blood to leak back into the chamber from which it came.
  
  
• Pregnancy. Being pregnant places additional strain on a woman’s heart and increases the risk of an aortic dissection.
  
  
• Diseases that affect collagen, which is a major component of connective tissue. These diseases include Marfan syndrome, Ehlers-Danlos syndrome and others.
  
  
• Inflammatory diseases that affect the blood vessels, such as Takayaso arteritis, giant cell arteritis, rheumatoid arthritis and syphilis associated with an inflamed aorta.
  
  
• Turner syndrome. A syndrome that affects women, causing underdeveloped and infertile ovaries. Coarctation of the aorta is not uncommon.
  
  
• Trauma. Chest trauma, such as occurs during a car accident and the person is slammed into the steering wheel, can cause aortic dissection.
  
  
• High intensity weight lifting can occasionally cause aortic dissection because of rapid and transient increases in blood pressure.
  
  
• Cocaine use. Cocaine can cause a rapid rise in blood pressure, which may then result in a tear of the lining of the aorta. The mortality rate from aortic dissection among cocaine users is nearly twice that of nonusers.

An aortic dissection can occur in any individual, but the condition is seen three times more often in men than women, and people with a family history of aortic dissection are generally at higher risk. Women are more likely to die from aortic dissection as compared to men, according to results of a study completed in 2004. Women also may have different symptoms, which may cause them to delay treatment.

Symptoms of aortic dissection may begin gradually or abruptly (acute aortic dissection). However, it is important to note that women experience different symptoms. In both sexes, chest pain is the primary symptom, but the intensity and type of chest pain may not be the same. This may cause women to delay in seeking treatment, which might be a reason more women than men die from aortic dissection. In the future, symptoms peculiar to women may be defined, which may improve women's survival rates.

Classic chest pain symptoms associated with aortic dissection are described as sharp, ripping, tearing or stabbing. It has been described as most intense at the onset of the symptom. This is in contrast to a heart attack, where the pain and discomfort typically intensifies gradually.

The location of pain is usually reported in the front of the chest below the sternum (breast bone) or on the back under the shoulder blades. Occasionally, pain is also reported in the abdomen or radiating to the neck, jaw, arm, shoulder, abdomen or hips. If the location of the pain changes, it may be a sign that the dissection is getting worse.

Other symptoms may include:

Weakness in one or both legs may occur if the aorta is blocked. In rare cases, stroke-like symptoms may occur (e.g., visual disturbances).

The signs physicians look for when diagnosing an aortic dissection in individuals are the five Ps: pain, paleness, pulselessness, paresthesia (numbness, tingling or heightened sensitivity in an area of the body) and paralysis (inability to move part of the body). The patient may also run a fever. In addition, patients with aortic dissection often have marked differences in their pulses from one arm to the other.

The diagnosis of an acute aortic dissection is an emergency medical procedure. When a patient appears in an emergency room with symptoms of a classic acute aortic dissection, the medical team will first seek to stabilize the patient and then make a definite diagnosis.

By using a stethoscope, physicians may identify sounds that are caused by aortic dissection.  A “blowing” diastolic murmur may indicate an aortic dissection. There may also be signs of cardiac tamponade (a medical emergency in which fluid rapidly fills the membrane surrounding the heart) or hypovolemia (an abnormally low volume of blood circulating in the body). A variety of noninvasive tests may be performed to confirm or rule out a diagnosis of an aortic dissection:

• Electrocardiogram (EKG). A recording of the heart's electrical activity as a graph on a moving strip of paper or video monitor. The highly sensitive electrocardiograph machine helps detect heart irregularities, disease and damage by measuring the heart's rhythms and electrical impulses. This test is chiefly used to rule out heart attack. In many cases, people with aortic dissection have a normal EKG. 
  
  
• Echocardiogram. This test uses sound waves to visualize the structures and functions of the heart. A moving image of the patient’s beating heart is played on a video screen, where a physician can study the heart’s thickness, size and function. The image also shows the motion pattern and structure of the four heart valves, revealing any potential leakage (regurgitation) or narrowing (stenosis). During this test, a Doppler ultrasound may be done to evaluate cardiac blood flow. The echocardiogram can help to visualize an aneurysm or a dissection flap in the aorta. It can also detect fluid (blood) in the pericardium due to leakage of blood from the aorta into the pericardial space. 
  
  
• Transesophageal echocardiography. During this test, a small sensor is placed into the esophagus, which is located close to the aorta.
  
  
• MRI (magnetic resonance imaging). An imaging procedure that uses magnetic fields and a computer to produce high-resolution cross-sectional or three-dimensional images of the target area (in this case, the heart). Because this test takes a long time, during which physicians have limited access to the patient, it is not considered the preferred approach for patients with acute aortic dissection.
  
  
• CAT scan (computed axial tomography scan). A radiographic imaging technique that takes x-ray pictures of tissues from various angles through the body. A computer is used to consolidate the pictures to create a detailed three-dimensional cross-sectional image.
  
  
• Chest x-ray. A radiation-based imaging test that offers the physician a picture of the general size, shape and structure of the heart and lungs. The distance of the shadow of the waist of the heart is wider than normal due to the dissection.
  
  
• Aortography. During this test, a contrast material is injected into the aorta that is visible under x-ray. This test has mostly been replaced by other, noninvasive imaging techniques but may still be used if the patient cannot undergo the other tests.

Many cases of aortic dissection are classed as medical emergencies that require rapid stabilization of the patient followed by surgery. Descending aortic aneurysms are often treated medically with good results. However, surgery may be necessary for these patients at some point if their condition worsens. Treatment may include medications such as:

• Antihypertensives. Medications that lower blood pressure, reducing strain on the heart. These may be given orally or intravenously.
  
  
• Analgesics. Medications to alleviate pain that may be given orally or intravenously.
  
  
• Beta blockers. Medications that slow the heart’s resting rate and reduce the force of the accompanying heart muscle contraction, thus lessening the heart’s workload and reducing the tension on the wall of the aorta. These may be given orally or intravenously.
  
  
• Antibiotics. Patients with Marfan syndrome are administered antibiotics prior to any surgical or invasive procedure to protect their heart valves, which are prone to infection.

Proximal aortic dissection requires urgent surgical intervention. More advanced cases of distal dissection that do not respond to medication are generally treated by surgery as well (open-heart surgery to repair or replace the dissected section of aorta).  

The survival rate for individuals undergoing elective, scheduled surgical repair of an aortic dissection is greater than 95 percent. While this procedure cures the dissection, it does not prevent future recurrence. Individuals with Marfan syndrome or a family medical history of an aortic dissection are more likely to develop additional aortic dissections in the future. Survival rates are lower for emergency, nonscheduled surgeries.

Early diagnosis and proper treatment of underlying conditions that put a patient at higher risk of an aortic dissection are important. Many cases, however, are not preventable.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to aortic dissection:

1. What kind of aortic dissection do I have?
   
   
2. What steps were taken to treat me?
   
   
3. What is the suspected underlying cause of my aortic dissection?
   
   
4. What medications will I need to take? Will I be on these medications for life?
   
   
5. What lifestyle changes should I make to lower my risk of another aortic dissection?
   
   
6. Can I exercise? Have sex?
   
   
7. If treatment is necessary in the future, are these less-invasive options available to me?
   
   
8. Will treating my underlying conditions help reduce the risk of aortic dissection?
   
   
9. How often should I visit your office for imaging tests to monitor my condition?
   
   
10. Are there any over-the-counter medications, nutrients or dietary supplements that I should avoid because they will aggravate my condition?