July 7, 2003
HOUSTON, TX - Each year, approximately 15,000 people die from Abdominal Aortic Aneurysm (AAA), making this disease the 13th leading cause of death in the U.S. AAA is the third leading cause of sudden death among men over the age of 60. AAA affects 1.5 million people in the U.S., with approximately 200,000 new cases diagnosed each year. Only about half of the 1.5 million people with AAA have been diagnosed, the other half remain undiagnosed.
AAA may go undetected because there are no symptoms. The disease is usually detected by accident - during screening and imaging tests, like X-rays, done for other medical reasons. However, as the general public becomes more aware of AAA, proactive testing and screening is becoming increasingly common.
An aneurysm is a ballooning of an artery resulting from a weakening or stretching of the arterial wall. Aneurysms may occur in any blood vessel, but the most common place is in the abdominal aorta just below the kidney arteries. The aorta is the large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.
An AAA is usually the result of hardening of the arteries. Other risk factors that are associated with the development of an AAA include cigarette smoking, high blood pressure, high cholesterol levels, family history, and chronic lung disease.
Most people do not experience any symptoms related to their AAA. During a routine physical examination, your doctor may notice a throbbing mass in the middle or lower part of your abdomen. Doctors treat aneurysms because, in many instances, if untreated, the large blood vessel can burst or rupture, causing life-threatening internal bleeding and death.
Unfortunately, most abdominal aortic aneurysms rupture suddenly. A few patients may experience new severe tearing-like back pain, but still not yet be ruptured. A patient with a pulsing abdominal mass, back pain, and low blood pressure is assumed to have a rupturing AAA until proven otherwise.
If an AAA ruptures, most patients die. Among celebrities, Roy Rogers survived a rupture, but he was the exception and not the rule. Albert Einstein, Lucille Ball, and Conway Twitty were not so fortunate.
Caucasian males over age 55 are at the greatest risk for AAA. In fact, aneurysms are among the top ten causes of death among this group. By about age 80, over 10 percent of Caucasian males will have developed an aneurysm. AAA occurs less frequently in Caucasian females, and they are relatively uncommon in African Americans of both sexes.
An AAA is treated if the doctor feels there is a risk that the aneurysm will burst. This depends on the size of the aneurysm.
The traditional treatment for AAA is a "conventional open operation." In this three to four hour surgical procedure, a six-inch incision is made in the patient's abdomen and the section of aorta where the aneurysm has formed is replaced with a synthetic graft. Patients typically spend one to two nights in an intensive care unit and remain in the hospital for an additional five to seven days.
Vascular surgeons at the Houston VA Medical Center (HVAMC) are currently treating patients with a new, minimally invasive AAA procedure, called "endovascular stent grafting."
In this procedure, a catheter is placed into the femoral artery in the leg. This artery leads to the aorta. The doctors use the catheter to place a small device called an endograft just under the kidney arteries. The endograft is expanded and fixed in place using the stent graft delivery system. The blood is now traveling through the endograft and not through the aneurysm.
"This new aneurysm operation typically takes between two to four hours to perform, and the patient experiences significantly less pain and discomfort following the procedure. Most of our patients are able to go home the next day," said Peter Lin, M.D., chief of the HVAMC vascular surgery section.
Lin along with two other HVAMC physicians, Alan Lumsden, M.D. and Ruth Bush, M.D. have collectively performed more than 500 of these new aneurysm operations. "We've performed more endovascular AAA operations than any other VA hospital system in the country, and our results have been superb. Many patients with difficult or complex aneurysms from other VA hospitals are routinely referred to us for treatment," said Lumsden.
In clinical trials conducted to evaluate the currently available stent-graft devices, the procedures were successfully performed in more than 97 percent of patients. The most common reason the procedure failed was the patient's blood vessels were too small or unhealthy to allow delivery of the stent graft.
"Patients who undergo this new endovascular AAA operation can usually resume their normal activities within a week following the operation. This is in contrast to the two to three months if they undergo the conventional operation. With patients who have underlying lung disease and do not tolerate general anethesia, we can perform this endovascular procedure using local anesthesia," said Bush.
The benefits of endovascular stent grafting include the reduction or elimination of the following: general anesthesia and mechanical ventilation, the amount of time that blood flow is decreased to vital organs and lower extremities, complications that may result from open surgery, and hospitalization and recovery time.
The HVAMC is now offering an ultrasound-screening program to evaluate patients for possible abdominal aortic aneurysms. If you would like to participate in this ultrasound-screening test, please contact the vascular surgery ultrasound lab at (713) 791-1414, ext. 7096.
The mention of a particular medical device in this story does not express or imply an endorsement of that product by the U. S. Government, the Department of Veterans Affairs, or the HVAMC.
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Point of Contact: VHAHOU Public Affairs04/21/04 08:25