Study Analyzes Best Approach for Treating Abdominal Aortic Aneurysms

bdominal aortic aneurysm (AAA)—a condition in which the large vessel that supplies blood to your abdomen, legs, and pelvis swells to over 50 percent its normal size—occurs in approximately 4 out of 100 adults. The risk increases with age, peaking after age 70. AAA is more common in men than women, and more common in smokers or former smokers than those who never smoked. If the aneurysm ruptures, most patients die before they even get to the hospital.

Since the 1950s, open surgery, in which the damaged portion of the aorta is replaced with a synthetic graft through a large surgical incision, has been the mainstay of AAA repair. Open surgery entails a substantial risk of death and complications, as well as a prolonged recovery period lasting months. Over the past decade, a newer procedure, called endovascular aneurysm repair (EVAR) has become increasingly popular. With this newer procedure, a fabric covered stent is delivered to the damaged site through the blood vessels via a catheter, thereby rerouting blood through the stent and away from the weakened wall of the aneurysm. Currently, about half of AAA repairs done in Medicare patients are performed using EVAR.

While EVAR is typically a less onerous procedure on the patient compared to open repair, there is concern that the repair might not be as durable, with a small ongoing risk of rupture requiring reinterventions, potentially leading to higher future mortality. So then, which intervention are doctors and patients to choose?

The largest study to date of over 45,000 Medicare recipients who had been treated for abdominal aortic aneurysms (AAA) shows that endovascular repair, a less invasive way to treat the condition compared with open surgery, has the best health outcomes for patients.

RELEVANCE
Ruptured AAA is the 10th leading cause of death in men over age 55 in the US with mortality of ruptured AAA exceeding 80%. In order to prevent rupture, repair is recommended for larger aneurysms. Many physicians feel that choosing between endovascular repair and surgery is a toss up, that while the former has better immediate health outcomes, the latter requires less reinterventions two to four years post procedure. This is the first large, national cohort study that addresses the issue, and it has found that when both short- and long-term effects are taken into account, endovascular repair is preferable.

INVESTIGATORS
Marc L Schermerhorn, MD, assistant professor of surgery, Division of Vascular and Endovascular Surgery, Beth Israel Deaconess Medical Center, 617-632-9971

In a large cohort study of over 45,000 Medicare beneficiaries treated for AAA, researchers at Harvard Medical School and Beth Israel Deaconess Medical Center have found that reinterventions of EVAR are balanced by late complications of open repair. When all these risks are factored together, the increased mortality of open repair makes EVAR the preferable option. Results are published in the January 31 edition of the New England Journal of Medicine.