Review question
To compare the effects of the pancreatic duct guidewire (PGW) technique with other endoscopic techniques for gaining access to the bile duct when access to the bile duct is considered to be difficult using traditional techniques.
Background
Endoscopic retrograde cholangiopancreatography (ERCP) combines endoscopy and X-ray to diagnose and treat problems of the bile ducts and pancreatic ducts. 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. Dye is injected into the bile duct, and X-rays are taken to look for gallstones or blockage. The major risk of ERCP is the development of inflammation of the pancreas (pancreatitis) by the dye or catheter, which occurs in 5% to 10% of all procedures. There is also a small risk of bleeding or making a hole in the bowel wall.
There are two traditional techniques for gaining access to the bile duct during ERCP. The first technique involves inserting a catheter directly into the papilla and injecting dye to confirm access to the bile duct, and the second involves the use of a guidewire to probe the papilla to gain access to the bile duct. Once the guidewire is confirmed on X-ray to be in the bile duct, dye is injected into the bile duct.
When accessing the bile duct using traditional techniques is difficult, the endoscopist can persist with the traditional techniques or use more advanced techniques such as blind incision into the papilla (precut sphincterotomy) or insertion of a stent into the pancreatic duct (PD) to facilitate access to the bile duct. The PGW placement technique is a new technique to gain access to the bile duct and to reduce the risk of postprocedure pancreatitis in people in whom traditional techniques fail to gain access to the bile duct. The PGW technique involves inserting a first guidewire deep into the PD. A second guidewire is then used to probe the papilla to gain access to the bile duct. The first guidewire facilitates access to the bile duct by blocking the PD opening.
Study characteristics
We conducted a search of the literature on 15 April 2016. We identified seven randomised controlled trials conducted in China, Japan, South Korea, Spain, Thailand, and the United States including a total of 577 participants. These trials compared the PGW technique versus persistent use of traditional techniques or other advanced techniques in people undergoing ERCP in whom access to the bile duct using traditional techniques was considered by the endoscopists to be difficult. As in clinical practice, the criteria used to define difficult access to the bile duct were highly variable among studies. We assessed outcomes of post-ERCP pancreatitis (PEP), success rates in accessing the bile duct, and other post-ERCP complications (bleeding, infection, hole in the bowel wall, death).
Key results
Contrary to popular belief, the PGW technique appears to increase the risk of PEP and does not improve the success rate of gaining access to the bile duct compared to other endoscopic techniques. The technique may increase the risk of mild PEP, but not moderate or severe PEP. There was no significant difference in success rates for accessing the bile duct. The risks for other complications such as bleeding, hole in the bowel wall, inflammation of the bile duct, and death appear to be low.
Quality of the evidence
Overall, we considered the quality of evidence for the outcome of PEP to be low. We considered none of the included studies to be at low risk of bias for all criteria. In most of the studies, both the participants and the medical staff were aware of which method was being used, therefore their judgments may not have been objective and the results should be interpreted cautiously.
In people with difficult CBD cannulation, sole use of the PGW technique appears to be associated with an increased risk of PEP. Prophylactic PD stenting after use of the PGW technique may reduce the risk of PEP. However, the PGW technique is not superior to persistent attempts with CC, precut sphincterotomy, or PD stent in achieving CBD cannulation. The influence of co-intervention in the form of rectal peri-procedural nonsteroidal anti-inflammatory drug administration is unclear.
Difficult cannulation is a risk factor for post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). It has been postulated that the pancreatic duct guidewire (PGW) technique may improve biliary cannulation success and reduce the risk of PEP in people with difficult cannulation.
To systematically review evidence from randomised controlled trials (RCTs) assessing the effectiveness and safety of the PGW technique compared to persistent conventional cannulation (CC) (contrast- or guidewire-assisted cannulation) or other advanced techniques in people with difficult biliary cannulation for the prevention of PEP.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and CINAHL databases, major conference proceedings, and for ongoing trials on the ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) up to March 2016, using the Cochrane Upper Gastrointestinal and Pancreatic Diseases model with no language restrictions.
RCTs comparing the PGW technique versus persistent CC or other advanced techniques in people undergoing ERCP with difficult biliary cannulation.
Two review authors independently conducted study selection, data extraction, and methodological quality assessment. 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 test (> 25%). To explore sources of heterogeneity, we conducted a priori subgroup analyses according to trial design, use of pancreatic duct (PD) stent, involvement of trainees in cannulation, publication type, and risk of bias. 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).
We included seven RCTs comprising 577 participants. There was no significant heterogeneity among trials for the outcome of PEP (P = 0.32; I2 = 15%). The PGW technique significantly increased PEP compared to other endoscopic techniques (RR 1.98, 95% CI 1.14 to 3.42; low-quality evidence). The number needed to treat for an additional harmful outcome was 13 (95% CI 5 to 89). Among the three studies that compared the PGW technique with persistent CC, the incidence of PEP was 13.5% for the PGW technique and 8.7% for persistent CC (RR 1.58, 95% CI 0.83 to 3.01; low-quality evidence). Among the two studies that compared the PGW technique with precut sphincterotomy, the incidence of PEP was 29.8% in the PGW group versus 10.3% in the precut group (RR 2.92, 95% CI 1.24 to 6.88; low-quality evidence). Among the two studies that compared the PGW technique with PD stent placement, the incidence of PEP was 11.7% for the PGW technique and 5.0% for PD stent placement (RR 1.75, 95% CI 0.08 to 37.50; very low-quality evidence). There was no significant difference in common bile duct (CBD) cannulation success with the randomised technique (RR 1.04, 95% CI 0.87 to 1.24; low-quality evidence) or overall CBD cannulation success (RR 1.04, 95% CI 0.91 to 1.18; low-quality evidence) between the PGW technique and other endoscopic techniques. There was also no statistically significant difference in the risk of other ERCP-related complications (bleeding, perforation, cholangitis, and mortality). The results were robust in sensitivity analyses. The overall quality of evidence for the outcome of PEP was low or very low because of study limitations and imprecision.