Endoscopic papillary large balloon dilation: more questions than answers

In this issue of Endoscopy, Dr. Kogure and colleagues published the results of a Japanese multicenter randomized controlled trial (RCT) [1] in which patients with large bile duct stones were assigned to either endoscopic papillary large balloon dilation (EPLBD) without endoscopic sphincterotomy (EST) or EST alone before removal of the bile duct stones. The inclusion criteria were patients with bile duct stones larger than 10 mm in size, distal bile duct greater than 12 mm in size, and the absence of distal biliary stricture. In this trial, a full EST was defined as one that reached the top of the transverse duodenal fold. The primary outcome was the rate of complete stone removal within a single endoscopic retrograde cholangiopancreatography (ERCP) session.

“…the stones must be large (> 10 mm) to warrant EPLBD and the lower end of the duct should also be sufficiently dilated to accommodate a large balloon; more importantly, the balloon should not be inflated beyond the size of lower bile duct.”

Randomization took place before the ERCP procedure using a stratified approach (< 15 mm and ≥ 15 mm). Four patients in the EPLBD-alone group underwent EST beforehand because of stone impaction in the distal bile duct (n = 2) or a narrow distal bile duct (n = 2). Three patients in the EST-alone group underwent additional EPLBD because of an intradiverticular papilla. The outcomes were analyzed in 86 and 85 patients from the EPLBD and EST groups, respectively. The rate of stone clearance in a single session was higher with the use of EPLBD when compared with the use of EST alone (90.7 vs. 78.8 %). The use of lithotripsy was less after EPLBD (30.2 % vs. 48.2 %).

The authors should be commended for their efforts in completing this multicenter trial. The results are perhaps not surprising, in that the large orifice created by EPLBD allows easier stone removal and reduces the need for lithotripsy. The more clinically relevant question was of course whether large balloon dilation without an EST would be safer than EST alone. The rate of pancreatitis was 4.7 % in the EPLBD group and 5.9 % in the EST group (absolute difference −1.2 %, 95 % confidence interval −7.9 % to 5.5 %). Because of the sample size, the authors could not be more precise in their estimates of post-procedural complications. The trial was not sufficiently powered to detect a small difference in post-procedural complications.

There are currently three options to enlarge the papillary opening after successful bile duct cannulation; EST alone, an initial EST followed by large balloon dilation, and EPLBD without an EST. How has the literature informed our practice?

As the authors alluded, the concept of endoscopic papillary dilation was introduced in the 1990 s and the practice has largely been abandoned, at least in North America, because of the high risk of pancreatitis. In the US multicenter study by DiSario and colleagues [2], post-ERCP pancreatitis in the balloon dilation group occurred in 18 of 117 patients (15.4 %). Among the 18 patients, there were two fatalities. In this trial, the mean bile duct size was 10 mm and the stone sizes were between 5 and 6 mm. Endoscopic papillary dilation was limited to 8 mm only. In small ducts, primary balloon dilation is hazardous and should not be practiced.

In 2003, Ersoz et al. [3] reported the technique of EST plus dilation with a large balloon in a series of 48 patients with large bile duct stones. Balloons up to 18 or 20 mm were used. In these patients, large balloons were used as an adjunct after failed attempts to remove stones using EST. There have been several RCTs [4] that have compared combined EPLBD after an initial EST and EST alone. Similarly to the current RCT by Kogure et al., a lower rate of lithotripsy use is observed after EPLBD. In one study, the rate of cholangitis was higher after EST probably because of the incomplete stone removal after an EST. Increasingly we add EPLBD after EST, especially when we encounter difficulty in removing large bile duct stones and when the margin to extend an EST is indistinct. In theory at least, the practice of EPLBD avoids the bleeding and perforation risk of an extended EST.

Kogure et al. invite the question of whether an initial EST is necessary before EPLBD. There is a theoretical advantage, in that an initial EST separates the bile duct from the pancreatic duct and controls the direction of sphincter disruption on balloon dilation – perhaps an initial EST can reduce the trauma to the pancreatic duct orifice. The design of the RCT by Kogure et al. did not intend to compare EPLBD with or without the use of EST. In this journal last year, Park et al. [5] randomized 200 patients with bile duct stones > 10 mm in size to receive EPLBD alone or EPLBD with EST. The overall adverse event rates were low (6 vs. 4 %) and the pancreatitis rates were 1 % vs. 3 %, respectively. It appears that the outcomes following either approach were similar. No doubt more RCTs will emerge in due course.

What have we learnt from the current RCT? First, we must select our patients carefully. As illustrated by the trial’s inclusion criteria, the stones must be large (> 10 mm) to warrant EPLBD and the lower end of the duct should also be sufficiently dilated to accommodate a large balloon. More importantly, the balloon should not be inflated beyond the size of lower bile duct. Second, the trial reassures us that, when a prior EST proves difficult (e. g. in patients after a Billroth II gastrectomy and in those with significant coagulopathy), large balloon dilation is a legitimate and acceptable solution.

Finally, the long-term sequelae of EPLBD without EST are unknown. Bile duct dilation and a multiplicity of stones are the two most important factors predicting recurrence of bile duct stones and complications. We do not really know if we would preserve the sphincter function after EPLBD without EST, or whether sphincter preservation is of benefit. There are conflicting views: some believe that sphincter preservation, especially in young patients, can reduce ascending infection and recurrent stone formation. On the other hand, some argue that a sphincterotomy protects against future calculus impaction and therefore against cholangitis, should there be recurrent stones. A follow-up study would be of interest to practicing biliary endoscopists.

Publication History

Article published online:
26 August 2020

• References

• 1 Kogure H, Kawahata S, Mukai T. et al. Multicenter randomized trial of endoscopic papillary large balloon dilation without sphincterotomy versus endoscopic sphincterotomy for removal of bile duct stones: MARVELOUS trial. Endoscopy 2020; 736-744
• 2 DiSario JA, Freeman ML, Bjorkman DJ. et al. Endoscopic balloon dilation compared with sphincterotomy for extraction of bile duct stones. Gastroenterology 2004; 127: 1291-1299
• 3 Ersoz G, Tekesin O, Ozutemiz AO. et al. Biliary sphincterotomy plus dilation with a large balloon for bile duct stones that are difficult to extract. Gastrointest Endosc 2003; 57: 156-159
• 4 Xu L, Kyaw MH, Tse YK. et al. Endoscopic sphincterotomy with large balloon dilation versus endoscopic sphincterotomy for bile duct stones: a systematic review and meta-analysis. Biomed Res Int 2015; 673013
• 5 Park JS, Jeong S, Lee DK. et al. Comparison of endoscopic papillary large balloon dilation with or without endoscopic sphincterotomy for the treatment of large bile duct stones. Endoscopy 2019; 51: 125-132