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

Aspirin exposure and its association with metal stent patency in malignant distal biliary obstruction: a large international multicenter propensity score-matched study

BACKGROUND AND AIMS

Stent dysfunction is common after ERCP with self-expandable metal stent (SEMS) insertion for malignant distal biliary obstruction (MDBO). Chronic aspirin (acetylsalicylic acid; ASA) exposure has been previously shown to potentially decrease this risk. We aim to further ascertain the protective effect of ASA and to identify other predictors of stent dysfunction.

METHODS

This multicenter retrospective cohort study was conducted at 9 sites in Canada and 1 in the United States. Patients with MDBO who underwent ERCP with SEMS placement between January 2014 and December 2019 were included and divided into 2 cohorts: ASA exposed (ASA-E) and ASA unexposed (ASA-U). Propensity-score matching (PSM) was performed to limit selection bias. Matched variables were age, sex, tumor stage, and type of metal stent. The primary outcome was the hazard rate of stent dysfunction. A multivariable Cox proportional hazards model was used to identify independent predictors of stent dysfunction.

RESULTS

Of 1396 patients assessed, after PSM 496 patients were analyzed (248 ASA-E and 248 ASA-U). ERCP with SEMS placement was associated with a high clinical success of 82.2% in ASA-E and 81.2% in ASA-U cohorts (P = .80). One hundred eighty-four patients had stent dysfunction with a mean stent patency time of 229.9 ± 306.2 days and 245.4 ± 241.4 days in ASA-E and ASA-U groups, respectively (P = .52). On multivariable analysis, ASA exposure did not protect against stent dysfunction (hazard ratio [HR], 1.25; 95% confidence interval [CI], .96-1.63). An etiology of pancreatic cancer (HR, 1.36; 95% CI, 1.15-1.61) predicted stent dysfunction, whereas cancer therapy was protective (HR, .73; 95% CI, .55-.96). Chronic ASA use was not associated with an increased risk for adverse events including bleeding, post-ERCP pancreatitis, and perforation.

CONCLUSIONS

In this large, multicenter study using PSM, chronic exposure to ASA did not protect against stent dysfunction in MDBO. Instead, the analysis revealed that the etiology of pancreatic cancer was an independent predictor of stent dysfunction and cancer therapy was protective.

Factors associated with patency of self-expandable metal stents in malignant biliary obstruction

INTRODUCTION

Endoscopic self-expandable metal stent (SEMS) placement is the key endoscopic treatment for unresectable malignant biliary obstruction. The benefit of covered SEMS over uncovered SEMS remains unknown as are risk factors for SEMS dysfunction. This study aimed to determine the factors associated with patency of SEMS.

METHODS

Patients with unresectable malignant biliary obstruction who underwent endoscopic SEMS placement at Ramathibodi Hospital, during January 2012 to March 2021 were included. Patient characteristics, clinical outcomes and patency of SEMS were collected. The primary outcome were stent patency and factors associated with patency of SEMS. The factors were analyzed by univariate and multivariate analyses. Median days of stent patency, median time of patient survival, rate of reintervention and complications after SEMS placement were collected.

RESULTS

One hundred and fourteen patients were included. SEMS dysfunction was found in 37 patients (32.5%). Size of cancer (Hazard ratio (HR), 1.20, (95% CI 1.02, 1.40), p 0.025), presence of stones or sludge during SEMS placement (Hazard ratio (HR), 3.91, (95% CI 1.74, 8.75), p 0.001), length of SEMS, 8 cm (HR 2.96, (95% CI 1.06, 8.3), p 0.039), and total bilirubin level above 2 mg/dL at one month after SEMS placement (HR 1.14, (95% CI 1.06, 1.22), p < 0.001) were associated with SEMS dysfunction. The median stent patency was 97 days. The median patient survival was 133 days, (95% CI 75-165). The rate of reintervention was 86% in patients with SEMS dysfunction.

CONCLUSION

The size of cancer, presence of stones or sludge during SEMS placement, the length of SEMS, and total bilirubin level above 2 mg/dL at 1 month after SEMS placement were associated with SEMS dysfunction. The median time of stent patency were not statistically different in each type of stent, covered stent, partially covered stent and uncovered stent. Median survival time of patients did not associate with SEMS patency or dysfunction.

Acetylsalicylic acid for metal stent in malignant distal common bile duct obstruction: A randomized controlled trial

BACKGROUND

Endoscopic biliary drainage is the treatment of choice for patients with malignant distal common bile duct obstruction. Self-expandable metal stents have clinical advantages including an increased duration of patency that may be prolonged by acetylsalicylic acid (ASA) use. The aim of this study was to investigate whether ASA had a positive effect on the patency of self-expandable metal stents compared with placebo.

METHODS

This prospective, multicenter, double-blinded, and randomized placebo-controlled trial was conducted from October 2017 to May 2020 in Korea. Patients who underwent palliative endoscopic biliary drainage with self-expandable metal stents for malignant distal bile duct obstruction were enrolled, and allocated to ASA treatment or placebo. The study outcomes were the rate of stent dysfunction at 6 months, duration of stent patency, risk factors for stent dysfunction, and any adverse events.

RESULTS

Interim analysis included 24 and 28 patients in the ASA and placebo groups, respectively. There was no significant difference between the ASA and placebo groups in stent dysfunction (25.0% vs. 20.7%, P = 0.761) or the duration of stent patency (150.97 ± 10.55 vs. 158.07 ± 8.70 days, P = 0.497). Six patients experienced suspected ASA-related adverse events, and there was one lethal case.

CONCLUSIONS

ASA did not prolong stent patency. This study was terminated early because of the possibility of serious adverse events related to ASA treatment of these patients receiving palliative care.

[Mechanisms and prevention of biliary stent occlusion]

One of significant achievements of modern endoscopy is development of retrograde biliary stenting for obstructive jaundice. This method ensured widespread application of endoscopic decompression in the treatment of patients with malignant biliary obstruction as preparation before radical surgery and final palliative care. Endoscopic retrograde transpapillary stenting firmly took its place together with antegrade and percutaneous stenting. There are certain advantages of this technique including minimally invasiveness and favorable quality of life. However, this approach is associated with some drawbacks associated with stent occlusion and difficult correction of this complication. The maximum diameter of the plastic stent (PS) is determined by the width of the working channel of the duodenoscope. In this regard, self-expandable metal stents (SEMS) were developed to increase the diameter of bile drainage channel. SEMS are associated with prolonged function. However, there is another problem. It is a germination of SEMS followed by impossible removal of the stent for its subsequent replacement. A further step in development of endoscopic biliary stents was the use of special SEMS coating to exclude tumor or granulation ingrowth. The problem of biliary stent occlusion remains relevant despite some improvement of stenting results. Mechanisms of occlusion of biliary stents and prevention of these events are discussed in this review.

Aspirin for metal stent in malignant distal common bile duct obstruction (AIMS): study protocol for a multicenter randomized controlled trial

Background

Endoscopic retrograde biliary drainage (ERBD) is the treatment of choice for patients with malignant distal common bile duct (CBD) obstruction. Self-expandable metal stents (SEMS), which are commonly used in unresectable cases, have many clinical advantages, including longer stent patency. Although the expected patency of SEMS is around 8 months, it has recently been reported that the duration of SEMS’ patency in patients using aspirin is prolonged. Our study, therefore, aims to investigate the effect of aspirin on SEMS’ patency.

Methods/design

This is an investigator-initiated, prospective, multicenter, double-blind, randomized placebo-controlled trial that will be conducted from November 2017 in four tertiary centers in South Korea. We intend to include in our study 184 adult (aged ≥ 20 years) patients with malignant distal CBD obstruction for whom ERBD with SEMS was successfully performed. The patients will be randomly allocated to two groups, which will comprise patients who have either taken 100 mg aspirin or a placebo for 6 months after index ERBD. The primary outcome will be the rate of stent dysfunction, and the secondary outcomes will be the duration of patency, the rate of reintervention, and the occurrence of adverse events.

Discussion

The aspirin for metal stents in malignant distal common bile duct obstruction (AIMS) study should determine the efficacy of aspirin in maintaining metal-stent patency in patients with malignant distal CBD obstructive.

Trial registration

ClinicalTrials.gov, ID: NCT03279809. Registered on 5 September 2017.

Predictors of stent occlusion in patients with unresectable pancreatic cancer after biliary metal stents

BACKGROUND

Self-expandable metal stents (SEMS) are a widely accepted biliary endoprosthesis for patients with unresectable malignant biliary obstruction. Here, we identified predictors for the occlusion of SEMS in unresectable pancreatic cancer patients with biliary tract obstruction.

METHODS

Patients with a distal malignant biliary obstruction caused by unresectable pancreatic cancer who received partially covered SEMS (PC-SEMS) placement for the first time between January 2003 and January 2016 were retrospectively enrolled for analysis. The rates of PC-SEMS occlusion were evaluated. The possible predictors of PC-SEMS occlusion were analyzed using Cox regression analysis.

RESULTS

In total, 120 patients who received PC-SEMS for unresectable pancreatic cancer were identified. The rate of PC-SEMS occlusion was 37%. The median time to occlusion of PC-SEMS was 359 days. The major causes of occlusion included biliary sludge (61%) and tumor ingrowth (30%). Cox multivariate regression analysis revealed that inadequate alkaline phosphatase/gamma-glutamyl transferase decline (defined by a decrease of <50% within 2 wk after PC-SEMS placement) was the only independent predictor of stent occlusion (hazard ratio, 2.86; 95% CI, 1.28-6.25; p = 0.01) CONCLUSION:: Inadequate alkaline phosphatase/gamma-glutamyl transferase decline is a predictor of occlusion of first-time PC-SEMS placement in unresectable pancreatic cancer patients with biliary tract obstruction.

Association of covered metallic stents with cholecystitis and stent migration in malignant biliary stricture

BACKGROUND AND AIMS

ERCP with self-expandable metallic stent (SEMS) placement provides reliable and durable relief of malignant biliary obstruction. Our objective was to compare efficacy and adverse outcomes between uncovered SEMSs (USEMSs) and covered SEMSs (CSEMSs).

METHODS

A retrospective cohort study was performed of all consecutive patients who underwent ERCP with SEMS placement for the management of a malignant bile duct stricture. Comparative analyses on clinical success, patency duration, stent dysfunction, and adverse outcomes were performed. Univariate and multivariable analyses were performed to identify factors associated with stent dysfunction.

RESULTS

Six hundred forty-five patients underwent SEMS placement for the management of malignant bile duct stricture from 2008 to 2016. CSEMSs and USEMSs had similar rates of clinical success in relief of bile duct obstruction (93.0% vs 92.1%, respectively; P = .69) and patency duration (546.7 vs 557.9 days, P = .14). Among those with an intact gallbladder, the incidence of acute cholecystitis was higher in the CSEMS group compared with the USEMS group (7.8% vs 1.2%; P < .001). In the multivariable analysis, CSEMS use was associated with increased risk of stent migration (hazard ratio, 10.7; 95% confidence interval, 4.1-27.7).

CONCLUSIONS

CSEMSs and USEMSs have similar clinical success rates and patency durations in management of malignant bile duct stricture. CSEMSs, however, are associated with increased rates of migration and cholecystitis. Comparable efficacy and superior safety profile of USEMSs render a compelling argument for its place as the preferred choice of SEMSs in the management of malignant biliary stricture.

Congested bile can predict the outcomes of endoscopic stenting for hilar biliary malignancies

OBJECTIVE

Endoscopic management of malignant hilar biliary obstruction (MHBO) remains challenging, with relatively poor jaundice control and high infectious risk. The factors that affect the outcome of endoscopic therapy are still unclear. This retrospective cohort study aimed to investigate predictive factors for the outcomes of biliary stenting in patients with MHBO.

METHODS

Between June 2015 and June 2016, consecutive patients with MHBO who received primary endoscopic stenting and completed follow-up at our institution were identified and evaluated. All patients received full aspiration of congested bile followed by plastic or metal stent(s) placement. Clinical success was achieved in patients whose total serum bilirubin decreased by over two-thirds in a month.

RESULTS

A total of 64 patients were included. Among them, 28 received a single stent placement and 36 received multiple stent placements. Altogether 53 (82.8%) patients attained clinical success and 48 (75.0%) underwent re-interventions within 6 months. Multivariate analyses showed that only a total bile volume of ≥30 mL aspirated from the intrahepatic ducts predicted clinical success (OR 6.83, 95% CI 1.2-38.4, P = 0.029), absence of early post-endoscopic retrograde cholangiopancreatography cholangitis (OR 0.03, 95% CI 0.004-0.36, P = 0.001), and lack of re-intervention within 6 months (HR 0.10, 95% CI 0.05-0.22, P < 0.001) after initial endoscopic stenting.

CONCLUSION

The volume of congested bile may effectively predict treatment outcomes of endoscopic stenting for MHBO and guide the therapeutic strategy.