Risk factors of ineffective drainage in uncovered self-expandable metal stenting for unresectable malignant hilar biliary strictures.

Aim: In this study, we assessed the factors contributing to ineffective drainage in the initial transpapillary uncovered self-expandable metal stent (USEMS) placements in patients with unresectable malignant hilar biliary strictures (UMHBSs) (Bismuth type II or higher).

Methods: This was a retrospective, single-center study. A total of 97 patients with UMHBSs who underwent technically successful initial USEMS placements using endoscopic retrograde cholangiopancreatography (ERCP) were classified into the effective drainage group (n = 73) or the ineffective drainage group (n = 24). We then compared group characteristics, clinical outcomes, and drained liver volumes. Drained liver volume was measured by using computed tomography volumetry. The definition of effective biliary drainage was a 50% decrease in the serum total bilirubin level or normalization of the level within 14 days of stent placement.

Results: Univariate analysis showed that ineffective drainage was associated with the pre-ERCP serum total bilirubin level ( P = 0.0075), pre-ERCP serum albumin level ( P = 0.042), comorbid liver cirrhosis ( P = 0.010), drained liver volume ( P = 0.0010), and single stenting ( P = 0.022). Multivariate analysis identified comorbid liver cirrhosis (adjusted odds ratio [OR], 5.79; 95% confidence interval [CI], 1.30-25.85; P = 0.022) and drained liver volume < 50% (adjusted OR, 5.50; 95% CI, 1.50-20.25; P = 0.010) as independent risk factors of ineffective drainage.

Conclusion: Comorbid liver cirrhosis and a drained liver volume < 50% contributed significantly to ineffective drainage in the initial transpapillary USEMS placements for UMHBSs.