DURHAM, N.C. -- Success rates, not just the number of procedures performed, are better predictors of a physician's competence in one of the most technically challenging endoscopic procedures, Duke University Medical Center researchers have concluded.
The procedure studied is the endoscopic retrograde cholangiopancreatography (ERCP), a minimally invasive procedure used to diagnose and treat ailments of the bile ducts and pancreas. Not only is it a difficult procedure to perform, but it is one in which mistakes can cause serious complications, and even death, in patients.
While it had generally been felt that physicians who have performed between 50 and 100 ERCPs were technically competent, the Duke researchers found that by using success rates, it can take as many as 180 procedures before a physician can be considered adequately trained.
"The use of success rates is ideal because it takes into account the learning curves of individual physicians," said Dr. Paul Jowell, Duke gastroenterologist and lead author of the study. "Our study showed that 180 procedures is a rough threshold -- some physicians achieved competence with fewer, some with more.
"Since the risks of complication are high for ERCPs, it is very important that we ensure those who perform them have the necessary skills," Jowell said.
In an ERCP procedure, a physician must snake a camera-tipped endoscope down a patient's throat, through the stomach and into the duodenum. They must then locate the tiny openings where the bile duct and pancreas empty into the duodenum. From there, thin catheters are inserted into either the bile duct or pancreas, guided by moving X-ray images on a television monitor.
The results of the Duke study are published Dec. 15 in the Annals of Internal Medicine. Over a two-year period, the researchers graded the abilities of 17 Duke gastroenterology fellows as they performed 1,450 ERCP's. Fellows are physicians who have already completed residencies in internal medicine and are undergoing subspecialty training in gastroenterology. ERCP is one of the procedures fellows may learn during their fellowship.
Each step in the ERCP represents a distinct skill that a fellow can be deemed to have successfully mastered. At each stage of a procedure, the attending faculty gastroenterologist graded the fellow's success in achieving each objective.
If, for whatever reason, a fellow was unable to successfully complete a particular aspect of the ERCP, the supervising faculty member took over, so patients were not adversely affected, Jowell said.
"For the purposes of the study, we defined competence as an 80 percent probability of fully completing each stage of the procedure," Jowell said. "As a comparison, the attending physicians here at Duke have a 95 percent success rate."
Once the study was underway, the American Society of Gastrointestinal Endoscopy independently recommended the 80 percent threshold as an appropriate measure of success, Jowell said.
While many ERCPs are performed in major medical centers, both non-gastroenterologists and gastroenterologists may perform the procedure in hospital endoscopy suites. There are no binding national certification or credentialing standards for ERCP; individual hospitals or institutions set their own standards.
"One of the reasons we conducted this study was that we have observed that a fair number of the procedures had failed out in the community, and the patients then came to Duke," Jowell said. "We wondered how much of this was due to training, so we started looking at how we train our gastroenterology fellows."
The Duke gastroenterologists said the methods they developed for judging competency for their specialty could also be used in other specialties.
"We feel that this system of basing competence on the success of the intervention could be used in other areas, ranging from lumbar punctures to cardiac catheterizations," Jowell said. "This type of assessment is an effective way to combat assumed competence -- just because a physician is trained in a diagnostic procedure does not necessarily mean he can competently perform a more complicated therapeutic procedure."
As a result of the study, Duke's division of gastroenterology plans to reduce the number of fellows who will receive advanced training in ERCP in the future.
"Since we do 800 to 900 ERCPs a year, we are decreasing the number of fellows who will receive advanced training in ERCP from three or four each year to one or two per year," Jowell said. "This will allow us to concentrate the experience -- a smaller number of fellows will perform a greater number of procedures."
Also participating in the study were Dr. John Baillie, Dr. Stanley Branch, Dr. John Affronti, Cynthia Browning, and Barbara Phillips Bute. The study was supported by the Duke division of gastroenterology and the American College of Gastroenterology.