Though current American Society for Gastrointestinal Endoscopy guidelines for whether a patient suspected of choledocholithiasis should undergo endoscopic retrograde cholangiopancreatography (ERCP) are accurate, more restrictive criteria would improve specificity and positive predictive value, researchers have determined.
ERCP is a highly effective procedure but is associated with serious, potentially life-threatening risks. Researchers also noted that “adverse events associated with ERCP are a frequent cause of litigation against gastroenterologists,” highlighting the need for decisions driven by data rather than expert opinion (Gastrointest Endosc. 2017 Feb 4. doi: 10.1016/j.gie.2017.01.039).
Society guidelines recommend less invasive testing – such as baseline liver tests and abdominal ultrasound – prior to ERCP to rule out patients who do not need the riskier procedure. From there, the guidelines stratify patients by high, intermediate, or low risk, recommending higher-risk patients (greater than 50% probability of choledocholithiasis) to proceed to ERCP, and lower-risk patients to take more tests first.
Researchers at Sir Run Run Shaw Hospital, Hangzhou, China, studied 2,724 patients with suspected choledocholithiasis. The patients received biochemical testing, abdominal ultrasound, and definitive testing.
The researchers found that the American Society for Gastrointestinal Endoscopy high-risk criteria were able to provide greater than 50% probability that a patient had choledocholithiasis, but that the criteria would still lead to more than a third of patients undergoing unnecessary ERCP.
Two of the tests – abdominal ultrasound, and determining the level of bilirubin to be greater than 4 mg/dL combined with a dilated common bile duct – provided greater specificity and positive predictive value than did the broader society guidelines. Patients who are negative for both of these tests, the researchers recommend, should receive a less invasive magnetic resonance cholangiopancreatography prior to ERCP.