Aneurysms Difficult to Diagnose, Complex to Cure

by Food and Drug Administration (FDA)

Just before Christmas in 1964, officials of the Houston Methodist Hospital in Texas stood at the entrance awaiting the arrival of famous visitors: the Duke and Duchess of Windsor. But the former king of England and his commoner wife were coming to Houston for more than a visit. The duke was scheduled to undergo surgery during the holidays.

Four years earlier, British physicians had detected a small pulsating mass in the duke's abdomen. They diagnosed the mass as an abdominal aneurysm, a balloon-like dilation of the wall of the aorta, the large, sturdy blood vessel that comes out of the heart and branches into other arteries that carry oxygen and nutrients to all parts of the body. Such aneurysms can rupture spontaneously, with dire consequences.

The duke's medical advisers had monitored the aneurysm closely as it slowly grew larger each year. When the aneurysm suddenly grew dangerously large, they sent him to a renowned heart surgeon, Methodist's Michael E. DeBakey, M.D., a specialist in aneurysm repair. At that time, DeBakey did about a thousand such procedures each year, sometimes as many as six a day.

In an operation lasting little more than an hour, DeBakey cut out the swollen part of the aorta — normally less than an inch in diameter at this point in the body, but now the size of a large grapefruit — and replaced it with a 4-inch length of knitted Dacron tubing. The Duke of Windsor recovered without incident and lived until 1972, when he died of throat cancer at age 78.

Aortic Aneurysms

Although aneurysms may develop in the wall of any blood vessel in the body, they almost always form in an artery, such as the aorta. Aortic aneurysms that develop in the chest area, where the aorta branches off from the heart, are called thoracic aneurysms. Aneurysms that develop in the part of the aorta that extends through the abdominal area, as in the Duke of Windsor's case, are called abdominal aneurysms. About 90 percent of aortic aneurysms are abdominal.

Abdominal aneurysms are four times more common in men than in women, and are most prevalent in whites aged 50 to 80. Ruptured aortic aneurysms are the ninth leading killer of American men over 55.

When an aneurysm hemorrhages, blood pours into body cavities. Tissues beyond the rupture are deprived of blood and cannot function properly, causing shock and death if not treated promptly. The larger the aneurysm, the greater the risk of rupture. A person with an abdominal aortic aneurysm that measures over 21/2 inches in diameter (over 6 centimeters) faces a 50 percent chance of dying within one year; 75 percent within two years; and over 90 percent within five years.

About a quarter of those with abdominal aneurysms experience pain in the abdomen or lower back that may be mistaken for a kidney stone attack or a ruptured vertebral disk. But in most cases, there are no warning symptoms.

The doctor may see or feel a throbbing, tender mass in the middle or lower abdomen during a routine physical, or may discover the aneurysm by chance when ultrasound imaging is done for some other reason.

Since abdominal aneurysms less than 2 inches (5 centimeters) in diameter rarely rupture, physicians usually prescribe blood pressure-lowering drugs, such as beta blockers, to reduce the pounding of blood against arterial walls. Patients with small aneurysms are monitored regularly with full exams and imaging techniques.

When the aneurysm is large or when there are many, surgeons can replace all or most of the aorta with Dacron tubing. Jere W. Lord Jr., M.D., retired professor of surgery, New York University, calls this "probably the most difficult operation a surgeon is required to perform on a human patient."

Thoracic aneurysms may also be symptomless, and are sometimes discovered unexpectedly on a routine chest x-ray. If symptoms do occur, they include pain in the shoulders, lower back, neck, or abdomen. A dry, brassy cough that doesn't respond to cough medication is another warning signal. The swelling aneurysm may press on the nerve that opens and shuts the vocal cords, causing hoarseness, even loss of voice.

When blood works its way through a tear in the aorta's innermost wall and separates the layers of the artery wall, creating a second channel, a dangerous complication known as a dissecting aortic aneurysm results. The most common symptom is an excruciating tearing or ripping pain in the chest, often mistaken for a heart attack. Unless the aorta is repaired immediately, most people with a dissecting aneurysm die. About 60 percent of thoracic aneurysms dissect; abdominal aneurysms rarely do. Dissecting aneurysms are more common in blacks than whites.

Atherosclerosis, or hardening of the arteries, which weakens artery walls, is a factor in 95 percent of aortic aneurysms. High blood pressure may speed up damage to vessel walls. Aortic aneurysms may also result from congenital defects, heredity, injuries, diabetes, and syphilis.

More than half of patients with one aortic aneurysm will develop another, so physicians use a variety of tests, not available in the Duke of Windsor's time, to monitor their patients: computed tomography (CT) scans, ultrasound, echocardiography, or magnetic resonance imaging (MRI).

People who have Marfan's syndrome, a connective tissue disorder, tend to be particularly vulnerable to aortic aneurysms because of weak arterial walls. About 10 percent of patients with aortic aneurysms have Marfan's syndrome.

Berry Aneurysms

Aneurysms that balloon out to look like berries may form in congenitally weak spots in a ring of arteries at the base of the brain known as the circle of Willis. All the brain's major arteries open into this ring, which then circulates blood to the areas of the brain that control movement, sight, feeling, and thinking. The circle of Willis guarantees the brain a continual supply of blood in the event that one of these arteries, such as the carotid, is blocked.

Berry aneurysms have been aptly described as time bombs, because they are liable to burst at any time, resulting in hemorrhagic strokes that affect 30,000 Americans each year. One-third of such ruptures occur during sleep. About half of the people with ruptured berry aneurysms die immediately. Many of the survivors die later from recurring hemorrhage or suffer irreversible brain damage. Ruptured berry aneurysms are most common in people 40 to 60 years old, and in slightly more women than men.

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