More information To know more about AAA, visit www.vascularweb.org or www.sirweb.org For information about the AAA Screening Medicare Benefit contact the Society for Vascular Surgery at 1-800-258-7188 or e-mail: vascular@vascularsociety.org.

Patrick Knight's elder brother Edward died three days after the rupture of an abdominal aortic aneurysm at the age of 59. For a long time the artery had been bulging, but nobody knew.

Now Patrick, 69, of Sewickley considers himself lucky because he found out that his aorta, the main artery leading from the heart, had enlarged to a bursting condition when he had ultrasound screening for gall bladder problems.

"I wouldn't be here today had my aneurysm not been found by chance," the retired Carqueville Printing Co. salesman said with a chuckle.

Abdominal aortic aneurysm, also known as AAA, is the 13th leading cause of death in the United States, accounting for more than 15,000 deaths each year, according to the Society for Vascular Surgery.

It affects 8 percent of people over the age of 65 and men are four times more likely to have an aneurysm than women.

Patrick Knight's abdominal aorta, which is 2 to 2 1/2 centimeters in diameter normally, enlarged to 5 cm. To protect him from a deadly rupture, surgeons inserted an endovascular stent graft, a man-made tube, inside the damaged aorta.

With a family history of aneurysm, another brother, Tom, 73, is also mindful of what is called the "silent killer."

Although he doesn't have an aneurysm, Tom will have regular checkups to see if one develops, said Patrick, who has alerted many of his friends and acquaintances about the condition.

An aneurysm is the expansion of a weak portion of the abdominal aorta. The pressure from blood flowing through the aorta causes its weakened part to bulge, much like a balloon.

Although the aneurysm's exact cause remains unknown, the leading thought is that it's caused by inflammation in the aorta, which may cause its wall to break down.

Hardening of the arteries or risk factors that contribute to high blood pressure are also considered possible causes.

"The risk of aneurysm increases with age and it is much more common in men than in women," said Dr. Dean A. Healy, a vascular surgeon at Allegheny General Hospital's McGinnis Cardiovascular Institute. Dr. Healy, who repairs aneurysms with the stent graft, added that it's most common among people over 60 years old.

Since 1996, he has performed 309 surgeries on aneurysm patients.

Men with a history of smoking at least 100 cigarettes in their lifetime, people of either sex having a family history of an aortic aneurysm, and those with high blood pressure have the most risk of developing this condition, Dr. Healy said.

Three out of four aneurysms show no symptoms at the time they are diagnosed. When symptoms are present, they may include abdominal pain, pain in the lower back that may radiate to the buttocks, groin or legs, the feeling of a pulse in the abdomen, and, on rare occasions, the person's feet may develop discoloration or sores.

"Boy, you don't know you have it because there are usually no obvious symptoms of this disease," said William Hoffman, 71, of Crafton who underwent endovascular aneurysm repair on June 25.

After his brother, Fred, now 77, was found to have a 9 cm aortic aneurysm and had to undergo the operation, William's physician recommended a screening. He was diagnosed with a 4.6 cm aorta in December 2005.

A retired supervisor of data processing at Mailing Services of Pittsburgh, William Hoffman did not require surgery until his aorta reached 5.2 cm this year.

With the history of aneurysms in their family, doctors have suggested screening of his son, William Jr., 42, and daughter, Sharon Kolarac, 45.

Dr. Healy said people with an enlarging abdominal aorta can postpone surgery, under a doctor's observation, until the size reaches at least 5 cm.

First diagnosed with an enlarging aorta six years ago, Louis DeGrandis, now 82, of Latrobe was watched for years.

"I had to do serial ultrasound and CT [computerized tomography] scans to be sure that it was still doing OK," he said.

He had endovascular aneurysm repair on July 27 when the size of his aorta reached 6.3 cm.

When an aneurysm bursts, people experience sudden severe back or abdominal pain, paleness, dry mouth and skin and excessive thirst, nausea and vomiting and signs of shock, such as shaking, dizziness, fainting, sweating, rapid heartbeat and sudden weakness.

Once an abdominal aortic aneurysm has ruptured, the chances of survival are low, with 80 percent to 90 percent of all ruptured aneurysms resulting in death, according to the Society of Interventional Radiology.

After rupture, a patient experiences shock with a fall in blood pressure. This can lead to heart attack, kidney failure, lung failure, and clotting problems, Dr. Healy said.

After years of unsuccessful attempts to treat it surgically, Dr. Rudolph Matas of New Orleans, who was the first to use spinal anesthesia in the United States in 1889, performed the first successful aortic ligation on a human in 1923.

When Albert Einstein developed this condition in 1949, doctors put in a wrap around the aneurysm to restrict its growth, a relatively successful method then. But it could not cure him totally and Einstein died on April 18, 1955 in Princeton, a day after experiencing internal bleeding.

Treatment of aneurysms has progressed since then and currently there are three options for patients: watchful waiting (for aneurysms smaller than 5 cm) under the guidance of a vascular specialist, open surgical aneurysm repair and endovascular stent graft.

Open aneurysm repair, also known as surgical aneurysm repair, involves an incision in the abdomen. Surgeons replace the weakened part of the aorta with a tube-like replacement called an aortic graft to act as a bridge for the blood flow.

The endovascular stent graft, a minimally invasive technique also known as interventional repair, is a less invasive, newer method where surgeons use imaging to guide a catheter inside the patient's aorta by making an incision in the skin at the groin. A compressed stent graft is passed along a guidewire to the aneurysm and then opened, creating new walls in the blood vessel through which blood flows.

"This relatively new procedure eliminates the need for a large abdominal incision and eliminates the need to clamp the aorta," Dr. Healy said.

While patients need to stay in the hospital for four to seven days after an open surgical repair, those having the stent graft can leave in 24 to 48 hours.

Open surgical repair is not for everyone: Clamping the aorta creates significant stress on the heart, and people with severe heart disease may not be able to tolerate this major surgery. Patients at increased surgical risk due to age or other medical conditions are generally recommended for stent graft. There remain some patients who cannot have the stent graft, since it is only available in certain sizes.

Greater awareness of the threat of aneurysm is more likely now that Medicare expanded benefits for qualified senior citizens in January with a free one-time ultrasound screening benefit. The screening is part of the "Welcome to Medicare Physical Exam," which is formally called the Initial Preventive Physical Exam, or IPPE.

Each year, physicians diagnose approximately 200,000 people in the United States with an aneurysm. At least 95 percent of them can be successfully treated, if detected before rupture, according to the Society for Vascular Surgery.

"Aneurysms are most often found when a physician is performing an imaging test, such as an ultrasound, for another condition," Dr. Healy said. "So people at risk for having an aneurysm should not neglect it."

The most common test is ultrasound, a painless examination for imaging aneurysm with sound waves. Other methods are CT scan, MRI (magnetic resonance imaging) and arteriography (real time X-rays involving the use of dye).

Free screenings

Allegheny General Hospital is offering free screenings this fall. Patients can call 1-877-284-2000 to register and will be contacted later with the date and time of their screening.

The University of Pittsburgh Medical Center Division of Vascular Surgery, in conjunction with the American Vascular Association, is offering free screenings for abdominal aortic aneurysm, stroke risk and peripheral arterial disease on Sept. 22 at UPMC Shadyside. Call 412-623-3333 to make an appointment.

Ignorance is not bliss in the case of an aneurysm. For Patrick Knight, it was a close call and he was lucky enough to escape a rupture.

"You must insist your physician [approve] a screening to ascertain whether the fatal silent killer is growing inside you. You don't need to die needlessly," he said.