And your best bet, the study finds, is a surgeon who specializes in surgery on blood vessels, called a vascular surgeon. If you can't find one, at least try to go to a surgeon or a hospital with a high level of experience performing the tricky procedure.
These conclusions come from a new study by researchers from the University of Michigan Cardiovascular Center and published in the October issue of the Journal of Vascular Surgery. It's the first comprehensive national analysis of the differences in mortality risk for repair of intact abdominal aortic aneurysms, or AAAs, by surgeon specialty and experience, and hospital experience.
"The bottom line is that with a complex operation like this, experience counts," says senior author Gilbert R. Upchurch, Jr., M.D., an assistant professor of vascular surgery at the U-M Medical School. "And the experience of the individual surgeon may count even more than the sheer number of AAA operations at an individual hospital. This is important for individual patients, as well as policy makers, to realize."
More than 175,000 Americans are diagnosed with AAAs every year, most while the aneurysm is still intact. Tens of thousands have surgery to repair the weakened vessel wall, either electively, immediately post-diagnosis for severe problems, or after the aneurysm ruptures. Less than half of patients who suffer a rupture survive. In all, 16,000 people died from AAA-related causes each year.
The study looked at records from 3,912 Americans of all ages who had surgery to repair an intact AAA in 1997. The data are from the Nationwide Inpatient Sample, which samples hospitalization data for the nation.
The researchers classified each surgeon as a vascular, cardiac or general surgeon based on the number of different types of operations -- from heart bypasses to appendectomies -- he or she performed that year. No matter what their specialty, they were classed as high-volume surgeons if they repaired more than 10 AAAs in a year. Hospitals were also classed according to how many AAA repairs were performed there; high-volume hospitals had more than 35 AAA operations in a year.
Overall, 4.2 percent of patients who had an aortic aneurysm repaired died before they left the hospital, demonstrating just how risky the operation is. But only 2.2 percent of patients operated on by vascular surgeons died, compared with 4 percent for cardiac surgeons and 5.5 percent for general surgeons.
Aneurysms start as a tiny bulge in the wall of the body's largest blood vessel. They can stay intact or grow slowly for years, often without symptoms, before suddenly bursting open unpredictably. Or, a tear within the multi-layered wall of the aorta, called an aortic dissection, can grow and eventually lead to an aneurysm at the weakened spot. Patients whose aneurysms are found while they're still intact can have surgery to correct the problem, often using an artificial graft to bypass the weak area. But many patients go undiagnosed.
Half the patients in the study had their AAAs repaired by a general surgeon, while 27 percent were operated on by vascular surgeons and the remaining 23 percent had a cardiac surgeon.
Even after adjusting for patients' individual health problems and other risk factors, the analysis showed that the risk of death was 76 percent higher if a general surgeon performed the procedure than if a vascular surgeon or cardiac surgeon did it.
Patients operated on by a high-volume surgeon of any kind had a 40 percent lower chance of dying in the hospital than those whose surgeons were low-volume. Vascular surgeons were more than twice as likely as cardiac surgeons, and more than five times as likely as general surgeons, to be high-volume AAA repair surgeons.
Patients who had surgery in a high-volume AAA hospital had a 30 percent lower risk of death than those who went to less-experienced hospitals. Three percent of patients at high-volume hospitals died, compared with 5.5 percent of those at low-volume hospitals.
The best surgical outcomes, with a 2.4 percent mortality rate, were found in patients who had surgery at high-volume hospitals by high-volume surgeons of any type. Comparatively, the rate was 6.4 percent among patients who had surgery in a low-volume hospital with a low-volume surgeon.
"It looks like the differences in mortality and risk-adjusted mortality have something to do with the specific skill of operating on blood vessels, and the extent to which a surgeon and surgical team is able to practice that skill on many patients," says Upchurch. "Even if a vascular surgeon is not available in a given area, a cardiac surgeon or general surgeon who has the chance to repair many AAAs may produce good outcomes. But the best option is someone trained, specialized and highly experienced."
This means the nation's already short supply of vascular surgeons may find themselves busier than ever as the American population ages and baby boomers enter the highest-risk age groups (60s and 70s) for AAA. But, the researchers feel that the supply of experienced surgeons may be enough, though patients may have to travel to reach the nearest high-volume surgeon and hospital.
Meanwhile, the researchers feel their findings have important implications for health policy experts trying to improve outcomes by setting up systems for AAA patients to be referred for expert care. Such systems for other cardiovascular conditions and procedures have been based mainly on hospital volumes, but the new data suggest they should take into account the individual AAA-repairing experience of surgeons. Half the vascular surgeons in the study operated at low-volume AAA hospitals, and some split their time between several hospitals.
Even as the development of referral systems based on projected surgical outcomes continues, Upchurch and his colleagues hope that further studies can be done to find out exactly what factors might be responsible for the variation in mortality rate among surgeons of different backgrounds and levels of experience, and for hospitals with different AAA volumes.
In addition to Upchurch, the study's authors include Justin Dimick, M.D., John A. Cowan, Jr., M.D., James C. Stanley, M.D., Peter K. Henke, M.D. of the U-M; and Peter Pronovost, M.D., Ph.D., of the Johns Hopkins University Schools of Medicine and Hygiene and Public Health.
Journal
Journal of Vascular Surgery