Keywords
Endoscopic ultrasonography - Intervention EUS - Biliary tract
Innovative techniques and equipment have paved the way for interventional endoscopy
to evolve in the last one to two decades beyond conventional ERCP and EUS. For patients
with distal malignant biliary obstruction (DMBO) where transpapillary ERCP is unsuccessful,
endoscopic ultrasound-guided choledochoduodenostomy (EUS-CDS) or EUS-guided transhepatic
endoscopic retrograde cholangiopancreatography (ERCP) have provided alternatives to
percutaneous drainage. When executed well and for appropriate indications, these maneuvers
are equally exciting because they are beneficial to patients.
The article by Chieng M et al in the current issue of Endoscopy International Open
addresses another endoscopic technique that may offer patients biliary decompression
when ERCP is unsuccessful: EUS-guided gallbladder drainage (EUS-GBD). This maneuver
has a proven track record for patients with acute cholecystitis who are unfit for
surgical resection or require internalization of a percutaneous gallbladder drain
to improve quality of life [1]. Coupling the lumen-apposing metal stent (LAMS) with an electrocautery delivery
system has streamlined the procedure. Over-the-wire exchanges are minimized, procedure
times are shorter, and outcomes are improved. Broadly speaking, an EUS-GBD has a shallow
learning curve. There are fewer steps than a transhepatic ERCP and the target is larger
compared with EUS-CDS. Naturally, this maneuver is considered in DMBO when other endoscopic
options are exhausted in hopes of avoiding percutaneous transhepatic biliary drainage
(PTBD).
Chieng M et al is one of many authors who report exemplary rates of technical success
with EUS-GBD for DMBO, but one speculates how we should define clinical success in
this scenario. In Chieng’s study, clinical success was defined as at least a 50% decrease
in serum bilirubin within 3 days after EUS-GBD for malignant distal biliary obstruction,
which was achieved in all 28 subjects. Despite such high rates of initial success,
the authors report that not all patients normalized their bilirubin, and there were
three patients who ultimately underwent percutaneous transhepatic biliary drainage
(PTBD) and another had a repeat ERCP attempt at biliary stenting that was successful.
The largest study on EUS-GBD in DMBO was from Binda C et al in 2023 [2], in which 39 of 48 patients (81.3%) achieved clinical success with EUS-GBD. Clinical
success in this study was defined as at least a 66.5% decrease in serum total bilirubin
within 2 weeks of procedure. The authors noted that this decrease was slightly less
than the means reported for EUS-CDS, possibly leading to a delay in restarting chemotherapy.
There have been several systematic reviews and meta-analyses, although none comment
on definitions of clinical success [3]
[4].
These studies have demonstrated that EUS-GBD is technically feasible and safe. Notably,
Chieng, and Binda reported a technical success rate of 100% with acceptable serious
adverse event rates. However, what remains elusive is whether high clinical rates
of success as defined so far translate to the big picture goal when performing EUS-GBD.
Does a 50% to 66.5% reduction in bilirubin sufficiently equate to clinically significant
biliary decompression for the oncologist? Do any patients with EUS-GBD have their
chemotherapy regimen modified from a first-line agent or have their dose reduced because
their bilirubin would not normalize? Finally, should we define clinical success by
clinical course milestones instead of a percent reduction a lab value? The GALLBLADEUS
study from Debourdeau A, et al [5] has broached these questions, because they reported chemotherapy reinitiation rates
in their comparison between EUS-GBD and EUS-CDS. The hope is that such a trend continues
in future studies.
Until we further characterize how EUS-GBD may minimize interruptions and deviations
from medical therapy, prioritizing EUS-GBD as a rescue option for DMBO over PTBD (assuming
PTBD can eventually be internalized) may not provide the best outcome for patients.
Besides potential time lost waiting for a clinically significant bilirubin reduction
that may never arrive, there are (anecdotal) instances in which partial decompression
decreases duct dilation, rendering percutaneous or other endoscopic modes of biliary
decompression either difficult or impossible. In addition, articles written by Chieng
M, Binda C, and Debourdeau A are from seasoned experts who likely exhausted other
endoscopic modes of biliary decompression before EUS-GBD. We risk misleading less
experienced endoscopists who lack the support or resources to consistently execute
conventional ERCP, EUS-CDS, or transhepatic ERCP into believing EUS-GBD is equally
effective, potentially compromising downstream care of patients.
Interventional endoscopic ultrasound is an exciting space where adoption is widespread
and rapid once new techniques demonstrate superior results. EUS-guided gastrojejunostomy,
for example, has become first-line treatment for malignant gastric outlet obstruction
at many centers because multiple studies suggest better outcomes compared with enteral
stenting or surgery. EUS-GBD in the context of DMBO is intriguing, but because there
are other established endoscopic and percutaneous options, this technique should be
explored with redefined metrics of clinical success calibrated toward the clinical
course of patients.
Bibliographical Record
Sun-Chuan Dai. EUS-guided gallbladder drainage for distal malignant biliary obstruction:
How we can evaluate clinical success. Endosc Int Open 2025; 13: a26444867.
DOI: 10.1055/a-2644-4867
