From the Journals

Real-world evidence seen for metal stents in biliary strictures



A real-world analysis in the United Kingdom found that a fully covered metal stent is safe and effective at controlling anastomotic strictures (AS) following liver transplants.

Biliary AS occurs in an estimated 5%-32% of patients following a liver transplant. Generally, these have been managed by insertion of side-by-side plastic stents to remodel the stricture, but this often required multiple procedures to resolve the problem. More recently, transpapillary fully covered self-expanding metallic stents (FCSEMSs) have been introduced and they appear to perform equivalently to their plastic counterparts while requiring fewer procedures.

The new study “is yet another large experience demonstrating that use of fully covered metal stents for treating anastomotic biliary strictures is highly effective and also cost-effective because you really decrease the number of ERCPs [endoscopic retrograde cholangiopancreatographies] that are required to treat an anastomotic stricture,” said Vladimir Kushnir, MD, who was asked to comment on the study, which was published in Therapeutic Advances in Gastroenterology.

The researchers analyzed retrospective data from 162 consecutive patients who underwent ERCP with intraductal self-expanding metal stent (IDSEMS) insertion at nine tertiary centers. The procedures employed the Kaffes (Taewoong Niti-S) biliary covered stent, which is not available in the United States. Unlike conventional FCSEMSs, the device does not have to traverse the papilla. It is also shorter and includes an antimigration waist and removal wires that may reduce the risk of silent migration. Small case series suggested efficacy in the treatment of post–liver transplant AS.

There were 176 episodes of stent insertion among the 162 included patients; 62% of patients were male, and the median age at transplant was 54 years. Etiologies included hepatocellular carcinoma (22%), alcohol-related liver disease (18%), and nonalcoholic fatty liver disease (12%). The median time to development of a stricture was 24.9 weeks. Among all patients, 35% had previously received stents; 75% of those were plastic stents.

Overall, 10% of patients experienced stricture recurrence at a median interval of 19 weeks following stent removal. Median stent emplacement was 15 weeks, and 81% of patients had a resolution of their strictures.

Dr. Kushnir, from Washington University in St. Louis, highlighted the differences between the stent used in the study and those currently available in the United States. “This type of stent is a self-expanding metal stent that’s covered, but what’s different about it is that it’s designed to go completely within the bile duct, whereas a traditional fully covered metal stent traverses the major duodenal papilla.”

Despite those differences, he believes that the study can inform current practice in the United States. “In situations where you’re faced with a question of whether or not you leave multiple plastic stents in, or you put a full metal stent in that’s going to be fully within the bile duct, I think this data does provide some reassurance. If you’re using one of the traditional stents that we have in the United States and putting it fully within the bile duct, you do need to be prepared to have a little bit of a harder time removing the stent when the time comes for the removal procedure, which could require cholangioscopy. But this does provide some evidence to back up the practice of using fully covered metal stents fully within the bile duct to remediate anastomotic strictures that may be just a little too high up to treat traditionally with a stent that remains transpapillary,” said Dr. Kushnir.

The study also suggests an avenue for further research. “What’s also interesting about this study is that they only left the stents in for 3 months. In most clinical trials, where we’ve used fully covered metal stents for treating anastomotic biliary strictures, you leave the stent in from anywhere from 6 to 12 months. So with only 3 months dwell time they were able to get pretty impressive results, at least in the short term, in a retrospective study, so it does raise the question of should we be evaluating shorter dwell times for stents in treating anastomotic strictures when we’re using a fully covered metal stent that’s a larger diameter?” said Dr. Kushnir.

The authors noted some limitations, such as the retrospective design, small sample size, and lack of control group. They also noted that the multicenter design may have introduced heterogeneity in patient management and follow-up.

“In conclusion, IDSEMS appear to be safe and highly efficacious in the management of [post–liver transplant] AS,” concluded the authors. “Long-term outcomes appear good with low rates of AS recurrence.”

The authors declare no conflicts of interest. Dr. Kushnir is a consultant for ConMed and Boston Scientific.

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