Predictors of stent dysfunction in patients with bilateral metal stents for malignant hilar obstruction

Introduction: For unresectable hilar obstruction, restoring and maintaining biliary ductal patency are crucial for improved survival and quality of life. The endoscopic placement of stents is now a mainstay of its treatment, and bilateral stenting is effective for biliary decompression. This study aimed to determine the clinical outcomes of bilateral metal stent placement using large cell-type stents and the clinical predictors of stent dysfunction in patients with malignant hilar obstruction. Methods: We performed a retrospective analysis of patients who underwent bilateral metal stent placement using two large cell-type stents at two academic teaching hospitals between September 2017 and February 2019. The primary outcome was stent dysfunction. Secondary outcomes included predictors related to stent dysfunction and overall survival. Results: The study included 87 patients who underwent bilateral metal stent placement for malignant hilar obstruction. Technical success and clinical success were achieved in 80 patients (92.0%) and 83 patients (95.4%), respectively. During the follow-up period (median: 201, range: 18-671 days), stent dysfunction occurred in 42 patients (48.3%), and the median stent patency was 199 days (95% confidence interval [CI]: 181-262). In univariate analysis, age, cholangitis before stent insertion, and subsequent chemotherapy were found to be associated with the cumulative risk of stent dysfunction. In multivariate analysis, cholangitis before stent insertion (hazards ratio [HR]: 2.26, 95% CI: 1.216-4.209, P = 0.010) and subsequent chemotherapy (HR: 0.250, 95% CI: 0.130-0.482, P<0.001) remained as statically significant factors associated with the cumulative risk of stent dysfunction. The median overall survival was 288 days (95% CI: 230-327). Conclusion: The bilateral placement of large cell-type stents for malignant hilar obstruction was effective with high technical and clinical success rates and acceptable patency. Cholangitis before stent insertion was associated with shorter patency, and subsequent chemotherapy was associated with longer stent patency.