Techniques for gaining access to the bile duct for the prevention of post-procedure pancreatitis

Endoscopic retrograde cholangiopancreatography (ERCP) combines endoscopy and x-ray to diagnose and treat problems of the bile and pancreatic ducts. With the patient under sedation, an endoscope is passed down the oesophagus, through the stomach, and into the duodenum where the opening of the bile and pancreatic ducts (papilla) is located. A catheter is then inserted through the endoscope and through the papilla into the bile duct. Contrast dye is then injected into the bile duct and x-rays are taken to look for gallstones or blockage. However, the major risk of ERCP is the development of pancreatitis due to irritation of the pancreatic duct by the contrast material or catheter, which can occur in 5% to 10% of all procedures. This may be self-limited and mild, but it can also be severe and require hospitalisation. Rarely, it may be life threatening. There are additional small risks of bleeding or making a hole in the bowel wall.

In general, there are two techniques for gaining access to the bile duct during ERCP. The traditional technique involves inserting a catheter directly into the papilla and injecting contrast dye to confirm access to the bile duct. However, contrast dye may be unintentionally injected into the pancreatic duct. A second technique involves the use of a guidewire to probe the papilla to gain access to the bile duct. Once the guidewire is confirmed to be in the bile duct on x-ray, contrast dye is injected into the bile duct. There has been much debate as to which technique is better for the prevention of post-procedure pancreatitis.

This review compared the effect of the two techniques for gaining access to the bile duct in patients undergoing ERCP. Twelve studies, with a total of 3450 patients, were reviewed and provide the best available evidence. The use of a guidewire to gain access to the bile duct reduced the risk of post-procedure pancreatitis and increased the success rate of gaining access to the bile duct compared to the traditional technique involving injection of contrast dye with a catheter.

Authors' conclusions: 

Compared with the contrast-assisted cannulation technique, the guidewire-assisted cannulation technique increases the primary cannulation rate and reduces the risk of PEP, and it appears to be the most appropriate first-line cannulation technique.

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Background: 

Cannulation techniques have been recognized to be important in causing post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). However, considerable controversy exists about the usefulness of the guidewire-assisted cannulation technique for the prevention of PEP.

Objectives: 

To systematically review evidence from randomised controlled trials (RCTs) assessing the effectiveness and safety of the guidewire-assisted cannulation technique compared to the conventional contrast-assisted cannulation technique for the prevention of PEP.

Search strategy: 

We searched CENTRAL (The Cochrane Library), MEDLINE, EMBASE, and CINAHL databases and major conference proceedings, up to February 2012, using the Cochrane Upper Gastrointestinal and Pancreatic Diseases model with no language restrictions.

Selection criteria: 

RCTs comparing the guidewire-assisted cannulation technique versus the contrast-assisted cannulation technique in patients undergoing ERCP.

Data collection and analysis: 

Two review authors conducted study selection, data extraction and methodological quality assessment independently. Using intention-to-treat analysis with random-effects models, we combined dichotomous data to obtain risk ratios (RR) with 95% confidence intervals (CI). We assessed heterogeneity using the Chi² test (P < 0.15) and I² statistic (> 25%). To explore sources of heterogeneity, we conducted a priori subgroup analyses according to trial design, publication type, risk of bias, use of precut sphincterotomy, inadvertent guidewire insertion or contrast injection of the pancreatic duct (PD), use of a PD stent, cannulation device, and trainee involvement in cannulation. To assess the robustness of our results we carried out sensitivity analyses using different summary statistics (RR versus odds ratio (OR)) and meta-analytic models (fixed-effect versus random-effects), and per protocol analysis.

Main results: 

Twelve RCTs comprising 3450 participants were included. There was statistical heterogeneity among trials for the outcome of PEP (P = 0.04, I² = 45%). The guidewire-assisted cannulation technique significantly reduced PEP compared to the contrast-assisted cannulation technique (RR 0.51, 95% CI 0.32 to 0.82). In addition, the guidewire-assisted cannulation technique was associated with greater primary cannulation success (RR 1.07, 95% CI 1.00 to 1.15), less precut sphincterotomy (RR 0.75, 95% CI 0.60 to 0.95), and no increase in other ERCP-related complications. Subgroup analyses indicated that this significant risk reduction in PEP with the guidewire-assisted cannulation technique existed only in 'non-crossover' trials (RR 0.22, 95% CI 0.12 to 0.42). The results were robust in sensitivity analyses.

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