Most often, bulges in the aorta near the heart are found by accident. Should you be screened for this rare yet dangerous condition?
The aorta, the body’s largest blood vessel, arises from the heart’s left pumping chamber, then curves up and over the heart in a gentle arc. In some people, a weak spot in the aorta’s wall causes the vessel to bulge outward like a worn-out bicycle tire. Called a thoracic aneurysm, this stealthy condition develops slowly and silently, rarely causing symptoms. And while some thoracic aneurysms are relatively harmless, others cause catastrophic problems. An estimated one in 10,000 people has a thoracic aneurysm, although the exact prevalence is unknown.
“Most thoracic aneurysms are discovered on an imaging test done for some other reason,” explains Dr. Eric Isselbacher, associate professor of medicine at Harvard Medical School and co-director of the Thoracic Aortic Center at Massachusetts General Hospital. For example, an aneurysm might be visible on an echocardiogram (heart ultrasound) done during testing for an irregular heartbeat. Because the condition is so uncommon, testing everyone for a thoracic aneurysm doesn’t make sense. But certain people face a higher risk than others (see “Who needs to be checked?”).
The danger of a dissection
Finding a thoracic aneurysm early can be lifesaving, because having one puts you at risk of a dissection—a tear in the inner layer of the wall of the aorta that causes the layers of the aortic wall to separate, thereby weakening the wall. An extra channel can then form inside the aortic wall, causing blood to bypass branch vessels that feed certain organs or tissues, leaving them without a blood supply. If a break occurs in all three layers of the aortic wall, it’s known as a rupture. Blood pours from the aorta into the chest or abdomen, and this massive internal bleeding can quickly lead to shock and death.
Living with a thoracic aneurysm
Repairing a thoracic aneurysm is a major operation, so most people live with the condition as long as the bulge doesn’t grow bigger than about 5 to 5.5 centimeters in diameter. The larger the aneurysm, the more likely it is to rupture. These people should control their blood pressure and undergo periodic imaging tests—echocardiograms or computed tomography (CT) scans—to check the size of the aneurysm. It’s also important to avoid activities that involve grunting or bearing down, like lifting heavy weights, says Dr. Isselbacher. That type of straining increases pressure in the chest, which can briefly raise blood pressure to dangerously high levels and stress the wall of the aorta. But he recommends getting regular aerobic exercise, which has overall health benefits. And light to moderate weight training—as long as you can breathe normally enough to hold a conversation while doing so—is considered safe.
Know the warning signs
Dr. Isselbacher also makes sure his patients know what to do if they have symptoms of an aortic dissection, which is sudden, severe, sharp pain in the chest, neck, or back. Call 911, then tell the first responders and the doctors at the emergency room, “I have a thoracic aneurysm”—while pointing to your chest—“and I need a CT scan,” he says. (Pointing to the chest helps to avoid confusion with other types of aneurysms, such as those that occur in the belly or the brain.) The knee-jerk reaction is to assume a person with chest pain is having a heart attack, which is understandable because those are far more common, Dr. Isselbacher explains. But a CT scan in the emergency room can quickly show if your aneurysm has dissected or ruptured and enables you to get the correct treatment right away.
“Many people are under the mistaken impression that thoracic aneurysms ‘pop’ and you’re a goner,” says Dr. Isselbacher. In fact, most thoracic aneurysms actually dissect rather than rupture, and the death rate from a dissected aneurysm is about 1% per hour, so if you get to a hospital and get diagnosed within several hours, chances are good that you’ll be okay, he says.
Who needs to be checked?
Thoracic aneurysms fall into two categories based on their location. About half are found in the descending aorta (see illustration). These tend to be more common in older people who smoke and have high blood pressure and stiff, narrowed arteries. In contrast, aneurysms in the ascending aorta usually occur in younger people and sometimes in association with certain genetic conditions, including a bicuspid aortic valve. In this latter condition, which affects about 1% of the population, the aortic valve has two flaps instead of the normal three.
You should be tested for a thoracic aortic aneurysm if you have a bicuspid aortic valve;