Interobserver Agreement for Classifying Post-liver Transplant Biliary Strictures in Donation After Circulatory Death Donors

Introduction: Biliary strictures are a common complication of donation after circulatory death (DCD) liver transplantation (LT) and require multiple endoscopic retrograde cholangiopancreatography (ERCP) procedures. Three classification systems, based on cholangiograms, have been proposed for categorizing post-LT biliary strictures. We examined the interobserver agreement for each of the three classifications. Methods: DCD LT recipients from 2012 through March 2017 undergoing ERCP for biliary strictures were included in the study. Initial cholangiograms delineating the entire biliary tree prior to endoscopic intervention were selected. One representative cholangiogram was selected from each ERCP. Five interventional endoscopists independently viewed each anonymized cholangiogram and classified the post-LT stricture according to each of the three classification systems. The Ling classification proposes four types of post-LT strictures based on their location. The Lee classification proposes four classes based on location and number of intrahepatic strictures. The binary system classifies strictures into anastomotic or non-anastomotic types. The Krippendorff’s alpha reliability estimate was used to grade the strength of agreement as “poor,” “fair,” “moderate,” “good,” or “excellent” for values between 0–0.20, 0.21–0.4, 0.41–0.6, 0.61–0.08, and 0.81–1, respectively. Results: One hundred DCD LT recipients (age 57.07 ± 8.8 years; 71 males) were initially evaluated. Of these, 49 patients who underwent 206 ERCP procedures for biliary strictures were included in the analysis. One hundred thirty-nine cholangiograms were selected and subsequently classified by five endoscopists. Interobserver agreement for post-LT biliary strictures was 0.354 for Ling classification (fair agreement), 0.405 for Lee classification (fair agreement), and 0.421 for the binary classification (moderate agreement). The binary classification provided the least amount of detail regarding the location and number of biliary strictures. Discussion: The currently available classification systems for assessing post-LT biliary strictures have sub-optimal interobserver agreement. A better-designed classification system is needed for categorizing post-LT biliary strictures.