Ann Arbor, MI - Patients undergoing repair of intact abdominal aortic aneurysm (AAA) have a 76% higher mortality risk when a general surgeon performs the procedure instead of a vascular or cardiac surgeon, a study at the University of Michigan found. The report on the relative importance of surgeon specialty and experience as well as hospital volume with respect to mortality risk in AAA repair appeared in the October 2003 issue of the Journal of Vascular Surgery.1

The bottom line is that with a complex operation like this, experience counts.

"The bottom line is that with a complex operation like this, experience counts," said senior investigator Dr Gilbert Upchurch (University of Michigan, Ann Arbor). "And the experience of the individual surgeon may count even more than the sheer number of AAA operations at an individual hospital."

So far healthcare policies have exclusively focused on concentrating high-risk procedures such as AAA in high-volume hospitals, because they were associated with better outcomes. The study by the University of Michigan group, headed by Dr Justin Dimick, is the first US-wide analysis comparing not only hospital volumes but also individual surgeons with different areas of specialty and levels of experience in terms of mortality risk for repair of intact AAA.

They evaluated records of 3912 US patients undergoing AAA during 1997 in 536 hospitals in 22 states from the Nationwide Inpatient Sample and classified surgeons as vascular, cardiac, or general, as well as high-volume (>10 AAAs/year) vs low-volume surgeons. Similarly, hospitals were considered high volume if more than 35 repairs were performed there.

Half of all AAA procedures were done by general surgeons, 27% by vascular surgeons, and 23% by cardiac surgeons. Overall, mortality was 4.2%. However, only 1.9% of patients operated on by a vascular surgeon in a high-volume hospital died, compared with 6.3% of those treated by a general surgeon in a low-volume center.

Risk-adjusted analyses showed that procedures performed by highly specialized, high-volume surgeons at high-volume medical centers were associated with the lowest mortality rates, whereas a patient's risk of death was increased by 76% when the AAA was repaired by a general surgeon, as opposed to a vascular or cardiac surgeon. Overall, high-volume facilities were associated with a 30% mortality risk reduction, and surgeons performing a large number of procedures with an even greater 40% risk reduction.