When Do Surgery Risks Outweigh the Danger of AAA Rupture?

Originally Published MDDI July 2002

R&D DIGEST

Abdominal aortic aneurysms (AAAs) represent a potentially deadly condition if not adequately monitored and treated. According to a study conducted at the Department of Veterans Affairs Medical Center in Minneapolis, however, it may be better to delay surgical treatment of the condition unless the aneurysm exceeds 5.5 cm in diameter. The VA researchers further suggest that common risks associated with surgical treatment can pose a more serious hazard than a small aneurysm does. These risks can include such potentially deadly complications as heart failure or infection.

"Repair of a smaller aneurysm does not benefit the patient and may present greater risks than the aneurysm itself," says Frank Lederle, MD, of the Minneapolis VA Medical Center. "Because we know that most of these smaller aneurysms will never rupture, our ultimate goal is to repair the AAAs that will burst, and no others."

Lederle explains that, "Surgery becomes urgent once [this type of aneurysm] develops symptoms consistent with rupture—a medical emergency where rapid diagnosis and treatment are crucial to survival. This is a very different clinical situation from following an asymptomatic patient with periodic measurements and deciding when to operate. More than 80% of AAA repairs are elective."

Lederle explains that, during the study, "measurement was done by the usual practice of radiologists reading ultrasound or CT scans at the local VA hospital. This is generally how decisions are made in clinical practice, and we wanted our results to apply to practice settings."

Guidelines based on the researchers' findings could result in at least 20% fewer repairs, Lederle and his colleagues believe. They suggest that the result would be fewer deaths and better treatment options for patients, as well as certain cost benefits. Lederle says the study also demonstrated an extraordinarily high surgery-survival rate, approximately 98%, at the 16 VA hospitals that participated in the study. Lederle hopes these results will convince doctors to restrict AAA repair.

"The survival rate was one of the highest ever reported," he says. "We can attribute this to selecting good surgical candidates, and the skill of the VA surgical and postsurgical teams. If smaller-AAA surgery isn't advisable with our excellent surgery-survival rates, it's hard to imagine it being justifiable anywhere else," Lederle concludes.

The study was funded by the VA Cooperative Studies Program (CSP). An upcoming CSP study will compare conventional surgical treatment with endovascular repair techniques. The researchers hope to determine which repair method has the best long-term results. The study will begin this summer at 40 VA medical centers. Lederle says the study will include 1260 randomly selected patients and as many as 8 years of follow-up.

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