Office of Research & Development

 

Study sheds light on best fix for dangerous aorta bulges

Former Navy sailor Ronald Mortenson, 67, had surgery seven years ago at the Baltimore VA Medical Center to repair an abdominal aortic aneurysm. He was part of a VA study comparing two ways to fix the problem.
Former Navy sailor Ronald Mortenson, 67, had surgery seven years ago at the Baltimore VA Medical Center to repair an abdominal aortic aneurysm. He was part of a VA study comparing two ways to fix the problem.
Surgical success—Former Navy sailor Ronald Mortenson, 67, had surgery seven years ago at the Baltimore VA Medical Center to repair an abdominal aortic aneurysm. He was part of a VA study comparing two ways to fix the problem. (Photo by Mitch Mirkin)
 Dr. Frank Lederle, of the Minneapolis VA Healthcare System, has led major VA studies aimed at determined the best ways to repair abdominal aortic aneurysms-potentially dangerous bulges in the artery that carries blood from the heart.
Dr. Frank Lederle, of the Minneapolis VA Healthcare System, has led major VA studies aimed at determined the best ways to repair abdominal aortic aneurysms-potentially dangerous bulges in the artery that carries blood from the heart.
Aneurysm expert—Dr. Frank Lederle, of the Minneapolis VA Healthcare System, has led major VA studies aimed at determined the best ways to repair abdominal aortic aneurysms—potentially dangerous bulges in the artery that carries blood from the heart. (Photo by April Eilers)

"I've got good news and bad news."

That's what Ronald Mortenson's doctor told him seven years ago. The good news was that the skin cancer on the Navy Veteran's arm was gone. The minor surgery had gotten all of it and it hadn't spread. The bad news? The CT scan showed he had something called an aneurysm—a bulge—in his abdominal aorta. And it was a big one. The doctor feared it could burst and cause severe internal bleeding.

The Vietnam Veteran underwent surgery at the Baltimore VA Medical Center. Today Mortenson, 67, is alive and well. Until recently he went for annual CT scans to check on the repair to his aorta, an inch-thick artery that channels blood from the heart to the rest of the body.

Mortenson was one of 881 Veterans at 42 VA medical centers who took part in a study comparing two ways to fix abdominal aortic aneurysms. The results, published Nov. 22 in the New England Journal of Medicine, will help guide surgeons not only in the VA health system but worldwide. VA's Cooperative Studies Program funded the effort.

Comparing open, endovascular repair

"With these findings and some of the earlier studies, we now have very good data to help doctors and patients make the best decisions," said study leader Frank Lederle, MD, an internist at the Minneapolis VA Healthcare System.

Mortenson's aneurysm was repaired through endovascular surgery. Doctors threaded a thin cable through a small incision in the groin and into the aorta. They worked a metal mesh tube, or stent, up through the cable and placed it in the aorta to act like a tunnel for the blood to flow through.

Other patients in the study underwent "open repair." In this technique, doctors make a larger incision closer to where the aneurysm lies. They insert a polyester sleeve to line the aorta, and then reseal the aorta tissue around it.

Endovascular repair is less stressful on the body. The risk of death due to surgical complications is lower. But concerns have existed over how durable the repairs are. Lederle explains that patients undergo follow-up CT scans to check, among other issues, that the mesh device inserted into the aorta hasn't "migrated" up or down.

"We are looking at graft position, kinking, twisting, and especially endoleaks, or blood entering the space between the graft and the aneurysm wall," says Lederle.

If the endovascular stent doesn't stay snuggly in place, a deadly rupture or other problems could result.

The VA study, which followed patients up to nine years, found similar long-term survival rates for both types of repair. Endovascular repair was associated with better survival right after surgery and in the two or three years thereafter, but the statistical difference evened out in subsequent years. Six patients who underwent endovascular surgery eventually suffered a rupture. This was low compared to the rupture rates in similar clinical trials worldwide. No such events occurred in the open-repair group. Contrary to what the researchers expected, older patients appeared to do slightly better with open than with endovascular surgery.

Aneurysm size is crucial factor

Based on the new results and past findings, Lederle says, "I think we can say with some certainty that endovascular repair should not extend indications for abdominal aortic aneurysm repair to patients who shouldn't have open repair—that is, those who are too old or sick or who have aneurysms less than 5.5 centimeters in diameter."

Lederle is one of the nation's top experts on abdominal aortic aneurysms. An earlier VA study he led focused on the size threshold for deciding when to operate on aneurysms and when to just keep an eye on them. It found that repairing those less than 5.5 centimeters wide—about two inches—did not improve outcomes. The recommendation that emerged was that these smaller aneurysms should generally be left alone. Another study by his team documented a high rupture rate for large aneurysms in patients who were not able to undergo surgery—or who refused to do so. Results from the two studies appeared in the New England Journal of Medicine and the Journal of the American Medical Association in 2002.

Mortenson's aneurysm was 7.4 centimeters when it was caught on the CT scan. Partly based on the earlier VA research, doctors knew they had to operate right away.

Nowadays, the former sailor stays busy driving a cargo van around Baltimore-Washington International Airport. He used to smoke but quit 25 years ago, he says. Smoking and high blood pressure are two of the biggest risk factors for aneurysms. He is past the point now where he needs annual CT scans to check on his aortic graft, but he says he still makes it a point to come in for regular check-ups at the Baltimore VA.

"Sometimes we see people who have had endovascular repair fail to come back for the recommended follow-up imaging," says Lederle. "This puts them at risk for worse outcomes than are seen in randomized trials, where follow-up is quite good. Patients who do stick to follow-up imaging can expect results similar to what we saw in our trial, which were very good and no worse than with open repair overall."