Metal stents are effective treatment for blocked bile ducts
A multi-center analysis, led by Weill Cornell Medical College and published in the Journal of Clinical Gastroenterology, shows the use of temporary “fully covered self-expanding metal stents” (FCSEMS) can effectively fix a painful and potentially life-threatening benign biliary stricture - a severely blocked or narrowed bile duct.
“Benign biliary strictures can be managed and resolved with these new fully covered metal stents with flared ends. Our study findings are similar to the recent European study results in patients overseas who received the metal stents,” says Dr. Michel Kahaleh, chief of endoscopy in the Division of Gastroenterology and Hepatology, Department of Medicine, at the Center for Advanced Digestive Care at NewYork-Presbyterian Hospital/Weill Cornell Medical Center and professor of clinical medicine at Weill Cornell Medical College.
Narrowing or blockage of a bile duct can lead to the dangerous leakage of bile into the body’s organs and bloodstream. Bile is a necessary fluid produced by the liver that assists in the body’s digestive process. Bile ducts are the series of thin, connected tubes that transport bile from the liver through the body to the small intestines. Patients who experience a bile duct stricture may experience jaundice, severe pain, itchiness, weight-loss, elevated liver function tests, cirrhosis and liver failure over a period of a few weeks.
Biliary strictures can be cancerous or benign. A benign stricture can occur as a result of surgical injury or trauma, pancreas inflammation, scarring or hardening of bile duct tissue caused by chronic inflammation, recurrent gallstones or poor reconnection of tissues post-liver transplantation. A biliary stricture is often diagnosed with explorative endoscopy - a procedure that uses a thin flexible camera probe to hunt for blockages, CT imaging or MRI.
Surgery once played a pivotal role in the management of benign biliary strictures, but it’s associated with significant complications and mortality. Today, minimally invasive endoscopic stent placement has emerged as a less invasive and more successful therapeutic option.
Only permanent plastic stents are currently FDA approved for benign stricture indications. However, these plastic stents involve multiple endoscopic procedures and multiple large stents. Also, plastic stents are often associated with stent blockages and failure of long-term durable results for stricture resolution.
A consequence of the different cancers of the hepatobiliary system is blocked bile ducts. However, artificial catheters known as “stents” can remediate this problem. Stents are medical implants which reopen narrowed bile ducts to allow the outflow of bile. However, bacteria colonize these catheters forming dense communities, so-called biofilms. Inside these biofilms, bacteria are not only protected from the immune response initiated by the host but also from antibiotics.
Since the bacterial community is unable to be controlled via antibiotics, the catheters become blocked by the biofilms, which then have to be exchanged on a regular basis, an invasive process.
Scientists of the Helmholtz-Centre for Infection Research (HZI) in Braunschweig have analyzed biliary stents from patients being treated at the medical clinics in Salzgitter and Braunschweig. They would like to know which bacteria inhabit these stents so that such knowledge can facilitate the development of medications tailored to combat against development of these biofilms. The HZI-Scientists identified specific bacterial species as main colonizers of these stents. In addition they statistically evaluated the composition of the bacterial communities of the catheters. Their results have now been published by the scientific journal International Society for Microbial Ecology Journal.
The Scientists of the HZI Department “Microbial Pathogenesis” used material from biliary stents of patients where old catheters had been replaced by new ones. For this reason, they collaborated with the Surgery Clinic of the Braunschweig General Hospital and the Department of Internal Medicine of the Klinikum Salzgitter. The Klinikum Salzgitter is the most specialized and experienced clinic for biliary stent replacement in the region, where each week patients receive new biliary stents. “This had the advantage that we could compare a huge set of samples” Dietmar Pieper, Group leader in the Department of Microbial Pathogenesis said. “This huge set of samples could only be analyzed as we did not try to culture the bacteria on plates, but used sophisticated culture-independent methods” Pieper said. The main goals of the scientists were to determine the composition of the bacterial communities in different biliary stents, their interactions with each other and which bacteria most often occur.
FCSEMS are being tested in patients with benign biliary strictures to overcome the limitations of plastic stents, and the complications of their uncovered or semi-covered metal stent counterparts. The fully covered membrane design of FCSEMS prevents embedding and ingrowth of the stent into the bile duct’s wall.
The research study examined 133 patient cases performed between April 2009 and October 2010 at six centers. Each patient received a FCSEMS during an endoscopic stenting procedure to open his or her severely narrowed or blocked benign bile duct stricture and restore bile flow. A 40, 60 or 80 millimeter length metal stent was implanted via a thin catheter to the blockage site over a guide wire. The stent was then partially deployed and pulled against the stricture prior to full deployment. These temporary metal stents were implanted all in one endoscopic procedure and removed after an average of three months.
This study is the first to analyze the safety and efficiency of these implanted metal stents for benign stricture resolution after their removal. “The study showed the majority of patients who received a metal stent had symptom relief, negative imaging for stricture and no need for repeat stent replacement except the patients who underwent liver transplant,” says Dr. Kahaleh.
Stricture resolution after FCSEMS removal was 91.6 percent successful in post-surgical cases, 84.2 percent in gallstone related disease, chronic pancreatitis 80.7 percent, 80 percent in other etiology and, in more complex anastomotic strictures cases, it was 61.2 percent successful. Interestingly, patients who had stents placed for more than three months were 4.3 times more likely to have resolved strictures, while those with non-migrated stents were 5.4 times more likely to have resolved strictures. Also, nearly 73 percent of metal stents were successfully removed after an average of three months.
“Fully covered self-expanding metal stents are emerging as a promising therapeutic option in the treatment of benign bile duct strictures,” Dr. Kahaleh says. “We found very acceptable, high rates of stricture resolution after the use and removal of metal stents in all types of patients groups. Also, those with longer duration of stent placement that didn’t migrate had an increased likelihood of stricture resolution.”
Current data and the FDA support the use of plastic stents in the endoscopic treatment of benign bile duct blockages. However, this current research study reports previous plastic stenting doesn’t always hold up. In fact, the study shows failed plastic stenting had been performed in more than half of the study patients who underwent implant of metal stents. Also, researchers report previous plastic stenting was associated with a decreased rate of stricture resolution.
“It’s time to revisit the therapeutic options we offer our patients for this often sudden and painful benign bile duct narrowing and blockages,” says Dr. Kahaleh. “Our study shows that any type of benign biliary stricture except those related to liver transplant can be treated with these metal stents, and metal stents may just do a better job fixing benign strictures then plastic stents.”
The researchers report FCSEMS did have some minor complications in the patient population studied. After implantation, complications included stent migration (10.5 percent), post-procedural pain requiring hospital admission (6 percent), pancreatitis (2 percent) and stent occlusion (3 percent). Also, minimal stent removal complications included mild bleeding (1 percent), unraveling of the stent (2 percent) and hyperplastic reaction (1 percent).
According to the research team, further research investigation of FCSEMS is necessary in a prospective, multi-center randomized control trial to assess the long-term efficacy of these metal stents with a more than three-month average period of stent indwelling time.
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Study co-authors include Dr. Monica Gaidhane of Weill Cornell; Dr. Alan Brijbassie, Dr. Jayant P. Talreja and Dr. Bryan G. Sauer of the University of Virginia Health System, Charlottesville, Va.; Dr. Amrita Sethi, Dr. Marisa DeGaetani, Dr. John M. Poneros and the late Dr. Peter D. Stevens of Columbia University Medical Center; Dr. David E. Loren and Dr. Thomas E. Kowalski of Thomas Jefferson, in Philadelphia, Penn.; Dr. Divyesh V. Sejpal of Baylor Clinic in Houston, Texas; Dr. Sandeep Patel, Dr. Laura Rosenkranz and Dr. Kevin N. McNamara of University of Texas Health Science Center, San Antonio, Texas; and Dr. Isaac Raijman of Digestive Associates of Houston, Houston, Texas.
Weill Cornell Medical College
Weill Cornell Medical College, Cornell University’s medical school located in New York City, is committed to excellence in research, teaching, patient care and the advancement of the art and science of medicine, locally, nationally and globally. Physicians and scientists of Weill Cornell Medical College are engaged in cutting-edge research from bench to bedside, aimed at unlocking mysteries of the human body in health and sickness and toward developing new treatments and prevention strategies. In its commitment to global health and education, Weill Cornell has a strong presence in places such as Qatar, Tanzania, Haiti, Brazil, Austria and Turkey. Through the historic Weill Cornell Medical College in Qatar, the Medical College is the first in the U.S. to offer its M.D. degree overseas. Weill Cornell is the birthplace of many medical advances - including the development of the Pap test for cervical cancer, the synthesis of penicillin, the first successful embryo-biopsy pregnancy and birth in the U.S., the first clinical trial of gene therapy for Parkinson’s disease, and most recently, the world’s first successful use of deep brain stimulation to treat a minimally conscious brain-injured patient. Weill Cornell Medical College is affiliated with NewYork-Presbyterian Hospital, where its faculty provides comprehensive patient care at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. The Medical College is also affiliated with the Methodist Hospital in Houston.
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Lauren Woods
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Weill Cornell Medical College