Introduction
Acute cholecystitis (AC) is a relatively frequent complication of ERCP with placement of self-expandable metal stents (SEMS) for distal malignant biliary obstruction (DMBO). SEMS design seems irrelevant, whereas neoplastic Cystic duct infiltration (CDI) has been claimed to be the most important independent predictor. However, data regarding incidence and risk factors are scant.
Aims & Methods
The primary aim of this study was to evaluate the incidence and risk factors of AC following ERCP with SEMS placement in patients with DMBO clustered according to the presence or absence of CDI evaluated by EUS.
This is a single tertiary center prospective study conducted between Feb-2024 and Jan-2025. All consecutive patients candidate to EUS and ERCP for characterization and endoscopic treatment of DMBO treated with a partially covered SEMS were included in the study (ClinicalTrials.gov identifier NCT04813055).
Two independent endosonographers blindly assessed the presence of CDI and other morphological risk factors (such as cholelithiasis or cholecystitis) at EUS.
Two independent endoscopists estimated CD coverage by the SEMS and other risk factors (such as gallbladder cannulation and contrast opacification) at ERCP.
Clinical outcomes were evaluated by one independent assessor during admission, at 30 days and then every 60 days.
The primary outcome was the onset of AC among patients with and without CDI. Risk factors for AC were evaluated through multivariate logistic regression model.
Results
A total of 109 patients with DMBO were included (median age 71 [IQR 62-77], female 38.5%, pancreatic adenocarcinoma 87.2%).
At EUS, prevalence of CDI was 16.5%; gallstones and sludge were present in 6.4% and 73.4% of cases.
At ERCP, where a 6-cm and 4-cm SEMS were used in 64.2% and 34% of cases, the CD was covered by the SEMS in 40.7% of the procedures.
Median follow-up was 94 [35-175] days.
Seven (6.4%) patients experienced post-ERCP pancreatitis whereas 8 (7.3%) experienced post-ERCP AC, after a median time of 6.5 [5-31] days post-procedure. AC required additional intervention in 57.1% of cases.
The rate of post-ERCP AC did not differ between patient with and without CDI, being 11.1% versus 6.6%, p=0.503.
Amongst patients with AC, ASA scores were lower while placed SEMS were longer, and the rate of CD coverage was significantly higher (87.5% versus 37%, p=0.005); the rate of CDI was higher but the difference was not significant.
At multivariate analysis, CD coverage by the SEMS was the only independent predictor of post-ERCP AC (OR[95% CI] = 13.8 [1.5-123.6].
Conclusion
In the context of SEMS placement for DMBO, post-ERCP AC is relatively more frequent than post-ERCP pancreatitis. EUS ahead of ERCP can help in predicting morphological risk factors for this event.
Coverage of the cystic duct by the SEMS appears to be the most important predictor, independent of cystic duct infiltration, potentially proposing a new high-risk group for this event, to be validated in future studies.