In 2023, the Society of Interventional Radiology (SIR) Foundation awarded the percutaneous cholangiopancreatoscopy (PCPS) registry the largest grant to date to investigate the use and role of cholangioscopy in the treatment of gallbladder and biliary tree lesions with the goal of removing indwelling drainage catheters quickly, treating biliary stones and diagnosing and treating strictures. Although cholangioscopes are not new and have been used for decades during gastrointestinal interventions and by a small number of interventional radiology (IR) practices, recent advancements in technology have begun to make new of old, drawing scopes to the forefront of a novel era of biliary intervention.
“Percutaneous biliary endoscopy has come to the procedural forefront in the past five years,” said Harjit Singh (Johns Hopkins University, Baltimore, USA), lead researcher for the PCPS registry, when speaking to Interventional News. “Prior to that time, only a few large academic centres were performing the procedure.” Since the early 1990s, laparoscopic cholecystectomy has typically been the gold standard for patients with symptomatic gallstones, which involves the surgical removal of a diseased gallbladder. However, when considered in an aging, increasingly comorbid, and so surgically unsuitable patient population, this treatment option is unviable. For these patients, percutaneous drains can be inserted into the gallbladder, but these require regular changing. Cholangioscopy can improve the efficiency of such procedures and the patient’s quality of life (QOL).
Percutaneous cholangioscopy is a minimally invasive procedure used to diagnose and treat conditions affecting the biliary tree and gallbladder. This typically involves the insertion of a flexible endoscope into the biliary system, enabling visualisation of the gallbladder lumen or bile ducts for the removal of stones, to place stents, treat strictures or perform biopsies. When the biliary tree/gallbladder cannot be approached endoscopically, percutaneous access with the placement of a drainage catheter is usually the first step. For choledocholithiasis and cholelithiasis, percutaneous scope-directed lithotripsy with fragment removal is increasingly being used as an effective minimally invasive option.
Although a smattering of medium-sized studies have evaluated the effectiveness of cholangioscopy and eventual tube removal, no large studies have been conducted to date. In 2022, to begin filling these gaps in understanding, Singh led the SIR Foundation research consensus panel, identifying crucial priorities regarding percutaneous image- and cholangioscopy-guided procedures for biliary and gallbladder diseases.
“Bringing together experts who have performed cholangioscopy was critical,” he commented. They identified three key areas of future research: the treatment of benign biliary strictures, the evaluation and treatment of intrahepatic cholangiocarcinoma (IHCC), and cholelithiasis/ choledocholithiasis in patients not suitable for surgery. Based on the response the panel received, Singh and his team determined that a multisite registry would be the best vehicle to collect these data and—with the sponsorship of the SIR Foundation—have enrolled close to 500 patients.
Moving beyond specialised academic centres, Singh stated that percutaneous cholangioscopy’s maturation can be attributed to the technological advancements of recent years. Sharing his experience, Hugh McGregor (University of Washington Medical Center, Seattle, USA) explained that the broader market availability of smaller, disposable scopes “lowered the barrier to entry”, making the procedure more accessible to IR teams. Previously, clinicians would need to buy a reusable endoscopic system or borrow one from another speciality, creating “challenges” for various reasons, he added. “There is definitely a learning curve—it’s a new modality that interventional radiologists don’t typically come across. We’re used to looking at X-rays in real time, not videoscopic images,” McGregor said.
McGregor’s own research has focused on gallbladder cryoablation, having conducted a first-in-human trial in 2020 which found the modality to be a promising alternative to long-term cholecystostomy tube drainage for the treatment of cholecystitis in non-operative patients. “When you look at devitalisation of the gallbladder, there was a lot of work done in the 1970s and 1980s, but there seemed to be a gap in the 1990s into the 2000s, perhaps due to the advent of laparoscopic cholecystectomy becoming the absolute standard, despite still being a fairly morbid operation in some patient groups.”
McGregor noted however that the clinical problem has begun to resurface once more, defined by an aging population with increasingly complex comorbidities. To meet this need, investment in scope technology applied to minimally invasive IR techniques is increasing. “The growth in the number of patients we’re seeing is outpacing the number of doctors we’re gaining, which has driven speciality crossover and collaboration, each coming toward the centre to act as proceduralists,” McGregor said.
Peter Mueller (Massachusetts General Hospital, Boston, USA) backed the motion for multidisciplinary collaboration, identifying intensivists, surgeons, interventional radiologists and gastroenterologists as key players in the management of these patients. “Collaboration is extremely important,” Mueller said. “Some people worry about losing their turf, but this is one area that any specialty would be apprehensive to take on. Treatment options for patients with biliary/ gallbladder diseases have little to no long-term data or evidence, but at our hospital we can confidently say that percutaneous cholangiopancreatoscopy to place a drainage catheter is very effective.”
Mueller reiterates that data must be sought, particularly for the sake of patient QOL metrics; “the five-year survival of these patients may not be great, but what about the two-year survival rates—did they get cholecystitis again? Did their stents become clogged?” he said. “In fact, I’m going to go to my old hospital next week and encourage the team to look at this.”
“Quality of life is the most underrated metric in IR,” Mueller continued. “It’s all in the decision making, the talking to the family and in the follow-up.” Today, patients are more autonomous during treatment decision-making conversations. John Smirniotopoulos (MedStar Washington Hospital Center, Washington DC, USA) shared that, at his centre, “a new subset” of patients has emerged, self-referring from across the country and internationally for biliary colic secondary stones. In doing so, these patients elect to avoid surgery and undergo organ sparing gallstone removal via percutaneous cholangiscopy.
From a research perspective, Smirniotopoulos stated that the efficacy of such a procedure still needs “bearing out”, and that stone recurrence should also be an area of particular interest. McGregor also touched on recurrence rates, stating that: “increasing the body of literature is going to be important here. If it turns out that 100% of patients will experience stone recurrence at five years, that changes the treatment equation and there may be an argument for a higher-risk cholecystectomy upfront, but we just don’t know yet.”
Primed to bolster or bin scope-directed biliary intervention, Singh et al’s forthcoming registry data are hoped to equip IR with a “whole new set of tools for the diagnosis and treatment of biliary tract disease,” said Singh. “Using what I expect to be proven [via the PCPS registry data], through an adjunctive set of tools, we can accelerate the process of diagnosis and treatment of biliary pathology such as stones, strictures and obstruction.” Singh hopes that subsequently, a “new treatment algorithm” can begin, providing an alternative to the “long, tedious and financially burdensome” treatment algorithms that are available now for these patients and their families currently.
