Repeated cannulation attempts or late precut: which is more risky for post-ERCP pancreatitis?

We read with great interest the recent article by Mariani et al. relating to the effect of early precut sphincterotomy on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) [1]. In this clinical trial, patients who had difficult biliary cannulation were randomized to early precut (Group A) or repeated papillary cannulation attempts followed, in cases of failure, by late precut (Group B). The authors found that PEP developed in 5.4 % (10/185) of Group A and in 12.1 % (23/190) of Group B patients. The difference was significant (P = 0.02), and the authors concluded that early precut sphincterotomy for difficult biliary access has less risk of PEP than persistent cannulation attempts and delayed precut.

We agree with the authors that the early precut sphincterotomy technique for difficult biliary cannulation may reduce PEP. However, from the study data they presented, further discussion is warranted for the effects of the multiple cannulation attempts and late precut.

There were 190 patients in Group B of the study, 55 of whom had successful biliary cannulation after repeated attempt and “without precut” sphincterotomy and the remaining 135 patients required delayed precut sphincterotomy. The overall rate of PEP was 12.1 % (23/190) in this group, and 14.1 % in the “delayed precut” subgroup. These rates show that 19 of 23 patients with PEP were in the “delayed precut” subgroup, and the remaining 4 patients were in the “without precut” subgroup. We calculated that the rate of PEP was 7.2 % (4/55) in the “without precut” subgroup. The PEP rate nearly doubled in the “delayed precut” subgroup compared with the group “without precut,” with a 2.09 odds ratio. These data show that delayed precut has a more significant effect on PEP risk than repeated attempts. However, the authors concluded that “repeated biliary cannulation attempts are a real risk factor for this complication” and they ignored the possible effect of a late precut procedure. According to their data, to postpone the procedure to a second ERCP session, in cases of failed cannulation after 10 minutes of additional cannulation attempts, might be safer than a delayed needle-knife precut procedure. This result also contradicts their discussion that “the late precut strategy in the current series suggests that it is not the precut itself but the multiple repeated cannulation attempts are a risk factor for PEP.” We think the authors should not ignore the possible risk of the delayed precut procedure itself for PEP in the study, and this point should also be discussed clearly in the paper.

Another controversial issue is that in their data on Table 4, the overall number of patients with complications is 31 (16.3 %) in Group B, and the P value is 0.07 compared with group A. However, this number is not equal to the sum of each complication, which is 36. If there were 36 patients with complications in Group B, the P value goes to a significance level of 0.01 compared with Group A (by chi squared test). The table is designed on per-patient numbers; if there was more than one complication in the same patient, this should be clarified by authors.

• References

• 1 Mariani A, Di Leo M, Giardullo N et al. Early precut sphincterotomy for difficult biliary access to reduce post-ERCP pancreatitis: a randomized trial. Endoscopy 2016; 48: 530-535