Aspirin Use Is Associated With Reduced Risk of Occlusion of Metallic Biliary Stents

Abstract

Background & aims: Biliary self-expandable metallic stents (SEMSs) are widely used to treat malignant and benign conditions of bile duct. Despite their lower rate of occlusion and longer patency than plastic stents, SEMSs still have significant rates of occlusion. We aimed to identify factors associated with occlusion of biliary SEMS.

Methods: We performed a retrospective study of consecutive patients who underwent endoscopic retrograde cholangiopancreatography with biliary SEMS placement at the Cleveland Clinic Foundation from March 2011 to April 2016. We collected clinical, endoscopic, radiographic, and surgical data from medical records and performed multivariable analysis to identify factors associated with SEMS patency. Subjects that received minimal daily dose of 81 mg at the time of stent placement until the end of follow-up were assigned to the aspirin exposure group (n = 157) and compared with subjects with no aspirin exposure (n = 436). Patients were followed for a median 81 days. The primary outcome was hazard ratio for SEMS occlusion requiring an interventional maneuver for biliary drainage.

Results: We analyzed data from patients receiving a total of 593 biliary SEMS for treatment of malignant and benign conditions of bile duct. Stent occlusion was observed in 126 cases. Multivariable analysis showed that daily use of aspirin (81 mg or more) was associated with 51% lower risk of stent occlusion than in patients without daily use of aspirin (hazard ratio, 0.49; 95% confidence interval, 0.32-0.75). Furthermore, SEMSs had a longer duration of stent patency in patients in the aspirin exposure group (434.4 days) versus the no aspirin exposure group (339.9 days) (P < .001). Stricture location limited to distal bile duct (in comparison with strictures involving proximal extrahepatic duct) was associated with lower risk of stent occlusion (hazard ratio, 0.39; 95% CI, 0.22-0.71).

Conclusions: In an analysis of a large cohort of subjects with metallic biliary stent placement for malignant and benign conditions of bile duct, we associated daily use of aspirin (81 mg or more) with lower risk of SEMS occlusion and longer stent patency duration.

Keywords: Blockage; Comparative Study; ERCP; Surgery.