Aortic Dissection

An aortic dissection, sometimes referred to as a "dissecting aorta" or "dissecting aneurysm," is the most common catastrophe of the aorta. An aortic dissection begins with a tear in the inner layer of the aortic wall (the intima). The force of the blood entering the middle layer (the media) causes the tear to extend.

It typically extends distally (away from the heart) in the direction of blood flow but it may extend proximally (closer to the heart). As a result of the tear, blood is then channeled into the wall of the aorta, rather than the central lumen, separating the layers of tissues. This creates a "false lumen" and results in decreased oxygen delivery to important organs including the brain, heart, kidneys, and intestines. It also generates a weakening in the aortic wall with a potential for rupture.

An aortic dissection is a life-threatening emergency. As many as 40% of people who experience aortic dissections die instantly, and the risk of death increases 1-3% every hour. Between 75-90% of patients who experience the most common type of dissections (those located in the first part of the aorta) die within one week if not treated appropriately. While some types of aortic dissections do not require emergency surgery, most do. Regardless, patients with acute aortic dissections should be emergently referred to a center that specializes in the treatment of aortic diseases.

Dissection Animation (External Site)

What causes aortic dissection?

The reason for aortic dissection is still being understood. However, there are several risk factors associated with aortic dissection. They include:

hypertension (high blood pressure)
connective tissue disorders, such as Marfan's syndrome, Ehlers-Danlos syndrome, and Turner's syndrome
cystic medial disease (a degenerative disease of the aortic wall)
aortitis (inflammation of the aorta)
atherosclerosis
existing aneurysm
bicuspid aortic valve: presence of only two cusps, or leaflets, in the aortic valve, rather than the normal three cusps
trauma
coarctation of the aorta (narrowing of the aorta)
polycystic kidney disease (a genetic disorder characterized by the growth of numerous cysts filled with fluid in the kidneys)

CT reconstruction of an ascending aortic dissection (Type B)

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What are the symptoms of aortic dissection?

The most commonly reported symptom of an acute aortic dissection is severe, constant chest and/or upper back pain, sometimes described as "ripping" or "tearing." The pain may be "migratory," moving from one place to another, according to the direction and extent of the dissection. Other symptoms include neurological symptoms, loss of consciousness, leg or arm weakness and severe uncontrolled hypertension. Aortic dissections are frequently confused with heart attacks.

Ritter Rules are life-saving reminders to recognize, treat and prevent thoracic aortic dissection.

CT image of an descending aortic dissection (Type B dissection)

How is aortic dissection diagnosed?

If there is concern regarding aortic dissection, an emergent CAT scan (also known as a CT scan or computed tomography scan) with contrast should be performed regardless of kidney function. An echocardiogram (also called echo), a procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves, may also provide important information.

The physician will determine the most appropriate examination. When a diagnosis of aortic dissection is confirmed, immediate intervention, such as surgery, is often required.

What are the complications associated with an aortic dissection?

As many as 40% of people with aortic dissections die instantly, and the risk of the death increases 1 - 3% every hour. Other important complications include heart attack, stroke, bleeding, damage to the intestines, kidney failure, and paralysis.

What is the treatment for aortic dissection?

Aortic Root Replacement

While some types of aortic dissections do not require emergent surgery, the majority do. The decision regarding appropriate treatment should be made in consultation with an experienced surgeon who specializes in the treatment of aortic disease.

If the dissection is acute--occurring less than 2 weeks prior-- and involves the more proximal portions of the aorta, (eg, the root, ascending aorta, or aortic arch), emergent surgery is generally required. If the dissection involves the more distal aorta (eg, descending thoracic aorta or abdominal aorta), strict blood pressure is typically recommended. Surgery may be recommended for dissections of the distal aorta when it is believed to be the cause of ongoing back or abdominal pain, renal damage, paralysis, bowel ischemia, limb ischemia, or aortic rupture. Surgery may also be recommended when the aorta is significantly enlarged.

In the meantime, if an aortic dissection is found (or suspected), strict blood pressure control is needed with a target mean arterial pressure of 60-75 mmHg. Beta blockers (e.g. Esmolol, Propranolol, or Labetalol) are first-line treatment. Calcium-channel blockers (e.g. Verapamil and Diltiazem) can be used, particularly if there is a contraindication to beta blockers. Vasodilators (e.g. Sodium nitroprusside) can be used for refractory hypertension, but they never should be used without beta- or calcium-channel blockers. Vasodilators, including Hydralazine and Minoxidil, and beta-blockers that have intrinsic sympathomimetic action (e.g. Acebutolol, Pindolol) should be avoided.

Go to the treatment section to read more about surgical treatments for aortic disease, these include:

Biologic composite grafts

Endovascular and hybrid approaches
Valve repair and valve-sparing aortic roots (the David procedure)
Advanced cardiopulmonary perfusion techniques for cerebral and spinal cord protection

How do I prevent an aortic dissection?

Here are a few tips:

Control your blood pressure. If you have high blood pressure, get a home blood pressure measuring device to help you monitor and keep your blood pressure well controlled.
Regular monitoring of your aortic aneurysm by a physician specializing in aortic disease
Don't smoke. Or, if you do, take steps to stop.
Maintain an ideal weight. Follow a low-salt diet and exercise regularly.
Watch your cholesterol. Keep your cholesterol levels within a range that is recommended by your doctor.
Continue low-impact exercise (eg brisk walking). Avoid high-impact exercise that significantly increases your blood pressure (eg weight training)
Wear a seat belt. This reduces the risk of traumatic injury to your chest area.
Keep your doctor well-informed. If you have a family history of aortic dissection, let your doctor know.

For more info on lifestyle recommendation visit, IRAD online

If you are concerned that you have an aortic dissection, you should call 911 or go to your local emergency room immediately.

UCCAD physicians are available 24 hours a day, 7 days a week to accept transfers. Urgent hospital-to-hospital air transfer can be arranged by UCCAD within approximately 200 miles of Chicago.