Is the rate of post-ERCP pancreatitis not reduced by guide-wire cannulation?

We read with great interest the paper on the role of guide-wire cannulation with regard to post-ERCP pancreatitis (PEP) by Bailey et al. [1]. To date, the results for guide-wire cannulation in the prevention of PEP are conflicting [2] [3] [4]; Bailey et al. carried out a neat prospective randomized trial on this issue. In their study [1], interestingly, guide-wire cannulation improved the primary success rate for biliary cannulation during ERCP but did not reduce the incidence of PEP, compared with conventional contrast cannulation.

However, regarding the results for guide-wire cannulation and PEP, we are concerned about a methodological issue. This study was a crossover trial: if the endoscopist failed to cannulate with the randomized technique, then crossover to the other arm (guide-wire or contrast) occurred. Ultimately a substantial proportion of the enrolled patients (17.4 %, 72 of 413) were crossed over. The crossover design may be useful for the evaluation of successful cannulation rates using guide wire or contrast, as in the study of Katsinelos et al. [5] in the same issue of Endoscopy, but with regard to post-ERCP pancreatitis, however, the crossover could mix the results for the two arms with regard to PEP. Theoretically, where the patient has been crossed over, guide-wire cannulation following contrast injection could show a higher PEP rate because of the contrast injection part of the procedure, while contrast injection following guide-wire cannulation could show a lower PEP rate because of the guide wire cannulation. In addition, pancreatic stents were placed twice as frequently in the contrast arm compared with the guide-wire arm. Given these issues, therefore, it may be a premature conclusion that guide-wire cannulation can not reduce the rate of PEP. According to our own and other prospective randomized trials [2] [3] [6], a guide-wire cannulation performed by a single operator is associated with a low PEP rate. More refined methodology may be needed to clarify the role of guide-wire cannulation in the prevention of PEP.

Competing interests: None

References

• 1 Bailey A A, Bourke M J, Williams S J. et al . A prospective randomized trial of cannulation technique in ERCP: effects on technical success and post-ERCP pancreatitis.  Endoscopy. 2008;  40 296-301
• 2 Artifon E L, Sakai P, Cunha J E. et al . Guidewire cannulation reduces risk of post-ERCP pancreatitis and facilitates bile duct cannulation.  Am J Gastroenterol. 2007;  102 2147-2153
• 3 Lella F, Bagnolo F, Colombo E, Bonassi U. A simple way of avoiding post-ERCP pancreatitis.  Gastrointest Endosc. 2004;  59 830-834
• 4 Vandervoort J, Soetikno R M, Tham T C. et al . Risk factors for complications after performance of ERCP.  Gastrointest Endosc. 2002;  56 652-656
• 5 Katsinelos P, Paroutoglou G, Kountouras J. et al . A comparative study of standard ERCP catheter and hydrophilic guide wire in the selective cannulation of the common bile duct.  Endoscopy. 2008;  40 302-307
• 6 Lee T H, Park D H, Park J Y. et al . Can wire-guided cannulation (WGC) prevent post-ERCP pancreatitis? A prospective randomized trial.  Gastrointest Endosc. In press 2008 and. 2008;  67 AB328