Is wire-guided selective bile duct cannulation effective for prevention of post-ERCP pancreatitis by all endoscopists?

The interesting recent paper by Tse et al. presented an important result: a wire-guided cannulation technique increased the success rate of selective bile duct cannulation (SBDC) and reduced the risk of pancreatitis occurring after endoscopic retrograde cholangioscopic pancreatography (ERCP) [1]. While we respect and value this meta-analysis of outcomes after wire-guided cannulation, we recommend careful consideration of the following three important points.

First, we should consider whether wire-guided cannulation is an ideal SBDC technique for every endoscopist, or only for some. The randomized, controlled trials (RCTs) involved one, or at most two, sophisticated endoscopists performing wire-guided cannulation in a single-center setting. Because of skill bias, therefore, data from these single-center RCTs cannot be generalized and widely accepted as applicable to every endoscopist. To reduce skill bias, we conducted a multicenter prospective RCT of selective bile duct cannulation performed by multiple endoscopists (the “BIDMEN” study), as in a phase 3 study [2] [3]. Unfortunately, this objective RCT revealed no significant difference in post-ERCP pancreatitis [2]. We believe that the incidence of post-ERCP pancreatitis depends, not on the type of cannulation procedure used, but on the proficiency of the endoscopist employing the cannulation technique.

Next, we should consider the RCT design. We think that a non-crossover wire-guided cannulation study design would suit only skilled endoscopists, and therefore could not be generalized to apply to every endoscopist. In the meta-analysis of Tse et al. [1], no significant difference in post-ERCP pancreatitis was shown in the crossover RCTs comparing wire-guided cannulation with conventional cannulation techniques. We currently recommend a combination of these techniques with a flexible approach, according to the clinical use setting, as required.

Third, we would like to emphasize differences in the degrees of the backward-oblique-angle duodenoscopes (BOADs) used in previous RCTs. In our RCT, 15° BOADs were used, which are standard in Japan [2] [4]. We previously reported that using a 15° BOAD yielded a superior SBDC rate compared to that with a 5° BOAD, and did not require the bow-up function of the sphincterotome [4]. Recently, single-center- and multicenter-designed Japanese RCTs that used 15° BOADs and multiple endoscopists to compare SBDC with a conventional catheter and wire-guided cannulation have been reported [5] [6]. These RCTs revealed that wire-guided cannulation did not improve the success rate of SBDC or reduce the occurrence of post-ERCP pancreatitis. Thus, we should consider BOAD maneuvering during SBDC with emphasis on the ability to adjust to the axis of the bile duct [2] [4].

Finally, we should also reconsider the standardization of wire-guided cannulation techniques, devices, the training of endoscopists/guidewire manipulators, the BOAD used to facilitate SBDC, and methods for the prevention of post-ERCP pancreatitis [3].

• References

• 1 Tse F, Yuan Y, Moayyedi P et al. Guide wire-assisted cannulation for the prevention of post-ERCP pancreatitis: a systematic review and meta-analysis. Endoscopy 2013; 45: 605-618
• 2 Kawakami H, Maguchi H, Mukai H et al. A muticenter prospective randomized study of selective bile duct cannulation performed by multiple endoscopists: the BIDMEN study. Gastrointest Endosc 2012; 75: 362-372 , e1
• 3 Kawakami H, Isayama H, Kuwatani M et al. Wire-guided cannulation is not an ideal technique for preventing post-ERCP pancreatitis. Gastrointest Endosc 2012; 76: 223
• 4 Kawakami H, Maguchi H, Hayashi T et al. A prospective randomized controlled multicenter trial of duodenoscopes with 5° and 15° backward-oblique angle using wire-guided cannulation: effects on selective cannulation of the common bile duct in endoscopic retrograde cholangiopancreatography. J Gastroenterol 2009; 44: 1140-1146
• 5 Nambu T, Ukita T, Shigoka H et al. Wire-guided selective cannulation of the bile duct with a sphincterotome: a prospective randomized comparative study with the standard method. Scand J Gastroenterol 2011; 46: 109-115
• 6 Kobayashi G, Fujita N, Imaizumi K et al. Wire-guided biliary cannulation technique does not reduce the risk of post-ERCP pancreatitis: multicenter randomized controlled trial. Dig Endosc 2013; 25: 295-302