Features February 2011 Issue

Aortic Dissection Poses Life-Threatening Emergency

A weakened aortic wall can be repaired if diagnosed in time.

When American diplomat Richard Holbrooke died from a torn aorta in December 2010, it once again cast a light on a condition that also claimed the life of actor John Ritter in 2003. In Ritterís case, the aortic dissection, or tear, was the result of a previously undiagnosed congenital heart condition.

Surgical repair of a torn aorta can involve the use of synthetic grafts to replace damaged sections of the artery (A); while a stent may be useful to help keep a bulging section of aorta, known as an aortic aneurysm, from rupturing (B).

The more common causes of aortic dissection, according to Cleveland Clinic cardiac surgeon Marc Gillinov, MD, are high blood pressure and/or a weakening of the wall of the aorta. Diseases such as Marfan syndrome, a connective tissue disorder, can contribute to a weakening of the walls of the aorta and other blood vessels. The aorta is the largest artery in the body and carries blood from the heart to the rest of the body.

An aortic dissection affects only two out of 10,000 people in the U.S. It occurs when the inner lining of the aorta splits or tears and blood then seeps under that inner wall. That causes the tear to grow and severe bleeding can result. Ruptures in the aortic wall are often fatal. Holbrooke underwent emergency surgery, but died within 48 hours of symptoms first appearing.

The main symptom of aortic dissection is sudden chest pain, either in the front or back of the chest. Often the pain may move as the dissection grows along the length of the aorta. Pain may be felt in other areas, too, depending on the location of the tear in its relation to other arteries and organs.

An aortic dissection is often preceded by the development of an aortic aneurysm, a bulging of the aorta in either the chest (thoracic aortic aneurysm) or the abdomen (abdominal aortic aneurysm). A slight bulging may be left untreated if your doctor does not believe it is likely to rupture soon. A watch-and-wait approach is often employed until the aneurysm grows and appears likely to rupture. At that point, the aneurysm can be treated with a stent to control the flow of blood through the aorta and relieve pressure on the aortic wall at the point of the bulge, or with surgery. An open chest procedure can be done to remove the dissected portion of the aorta and replace it with a synthetic graft.

"If a person has a known aneurysm, it should be monitored carefully," Dr. Gillinov says. "In elective cases, the prognosis is excellent. For an emergency, the survival odds for a dissection in the part of the aorta nearest the heart is about 85 percent. For other parts of the aorta, the odds are lower and the surgery is often a much more complicated procedure."

Diagnosis and treatment

If itís determined that you may be experiencing an aortic dissection and you are able to get to a hospital, youíll likely be admitted to the intensive care unit, where you will be given drugs to lower your blood pressure and your heart rate. Emergency surgery to repair the dissection will usually follow quickly, though patients whose overall health would not make them good candidates for surgery may have a stent put in to try to treat the problem.

Part of what determines the type of treatment you receive is the location and size of the dissection. Some of the imaging technology used to diagnose an aortic dissection include a computed tomography (CT) scan, a magnetic resonance angiogram (MRA) and transesophageal echocardiography. The idea is that these imaging techniques can provide a clear picture of the health and functioning of the aorta and all the major blood vessels.

Because aortic dissections often occur where the pressure is greatest against the inner wall of the vessel, a common area for a tear is in the ascending aorta, which is the part of the aorta where it originates from the left ventricle. Usually dissections get bigger as they descend down the aorta.

The recuperation from aortic dissection surgery can be six to eight weeks, while stenting is a much less traumatic experience for the patient. Itís important to remember that stenting is not always an option in treating an aortic aneurysm. In either case, itís likely youíll be prescribed beta blockers and/or another form of blood pressure-lowering medication.

Whoís at risk?

Men are more than twice as likely as women to experience aortic dissection. The most common age for an aortic dissection to occur is between 50 and 55. Distal dissection, a tear in the aorta that is descending from the aortic arch, occurs more commonly in patients between the ages of 60 and 70.

Uncontrolled high blood pressure is to blame in about two-thirds of all aortic dissections.