Inclusion Criteria:  Age 19 or older Patients who treated with LDLT (Duct-to-duct anastomosis) Patients with confirmed anastomosis site biliary stricture using cross-sectional imaging study (CT, MRI/MRCP).  Exclusion Criteria:  Patients with age 18 or under Pregnant woman Patients unable to endoscopic (transpapillary) approach due to prior surgical history Patients who did not provide informed consent to participation in the study