ITHACA, N.Y. -- A surgical procedure to prevent strokes, involving the removal of plaque from the carotid artery, has a greater chance of ending in the death of the patient when the surgery is performed by surgeons who have been in practice the longest, according to a new Cornell University study.
"We found that surgeons performing carotid endarterectomies who got their licenses 20 or more years ago had the highest mortality rate among their patients -- about one out of a hundred," says Liam O'Neill, assistant professor of policy analysis and management at Cornell. "We found about half that rate among other surgeons, even when we controlled for patient risk."
O'Neill and two co-authors published their study in the September issue of the journal Neurology . They also found a relation between the mortality of endarterectomy patients and the number of times surgeons performed the procedure: Surgeons who performed the surgery once a year or less had a patient mortality rate that was three times higher than that of surgeons who performed the surgery more frequently. Neurosurgeons had the lowest rate of mortality among their carotid endarterectomy patients. Once surgeons performed the procedure at least three times in two years, there was no difference in patient outcomes.
"However, time in surgical practice was more important than surgical volume as a predictor of patient outcome," the researchers write. They argue that physicians who have been in practice the longest may be less likely to adopt new procedural improvements or may use more resident staff in their surgeries. In either case, their findings do not suggest that older surgeons treated riskier cases, since there were no significant differences among the surgeons in their patients' pre-procedure severity based on age, source of admission, other medical problems and other risk factors. Interestingly, one of the co-authors, Arthur Hartz, M.D., of the University of Iowa, found similar findings among surgeons who perform heart bypass surgeries. "So our findings and that of Dr. Hartz's other study certainly raise some interesting questions about acceptable surgical volume thresholds and other surgeon characteristics that warrant further investigation," says O'Neill, whose rese! ! arch focuses on the strategic and operational use of quantitative methods and information systems in health care. The third author is Douglas J. Lanska, M.D., a professor of neurology from the University of Wisconsin School of Medicine.
The researchers analyzed the outcomes of 12,725 carotid endarterectomies performed by 532 surgeons over a recent two-year period in Pennsylvania. (The carotid is an artery in the neck carrying blood from the heart to the brain.) In recent years, the number of carotid endarterectomies performed in the United States has increased dramatically in response to two studies showing the surgery's beneficial effects in preventing strokes among certain patients, particularly those whose carotid arteries have narrowed by 70 percent or more (a condition called stenosis). However, the procedure is a delicate one, and the researchers point out that insufficient information is available to determine how often surgeons should perform the procedure in order for risk levels to be deemed acceptable.
The study is one of several suggesting that independent audits of surgical results should become obligatory.
Contact: Susan S. Lang
Office: 607-255-3613
E-Mail: SSL4@cornell.edu
Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.
o For information on carotid endarterectomy:
http://www.americanheart.org/Heart_and_Stroke_A_Z_Guide/cendart.html
o For information on Liam O'Neill:
http://www.human.cornell.edu/faculty/facultybio.cfm?netid=lo22&facs=1
Journal
Neurology