April 27 : A new study has found that an anti-reflux valve developed to help esophageal cancer may also help those with bile duct obstruction.

The bile duct carries bile from the liver to the intestines. When this duct is obstructed from cancers of the pancreas, gallbladder, or bile duct, bile begins to backup resulting in jaundice, itching, fever, chills, other organ malfunctions and death.

Surgery to remove the tumours is generally the best treatment, but often the disease progresses too far to consider surgery. Consequently, a stent, a tiny, hollow tube, is inserted using a minimally invasive procedure to help improve the passage of bile. However, these stents frequently clog requiring repeat procedures to replace the clogged stents. The exact mechanism that leads to stent clogging is not known. There is a possibility that clogging occurs from contents from the intestines backflowing (refluxing) into the stent.

This bile duct stent with the ‘Dua Anti-Reflux Valve’, named after its inventor Kulwinder S. Dua, was cleared for use by FDA last year. Using a similar windsock design, Dua modified the valve and attached it to the bile duct stent that closes whenever the pressure in the intestines increases so as to prevent backflow into the bile ducts.

The study was conducted by Dr. D.N. Reddy at the Asian Institute of Gastroenterology in Hyderabad, India.

As part of the study, the researcher examined 60 patients in whom the bile duct was obstructed from cancer of the pancreas or the bile duct, after placing a standard biliary stent in 30 patients and the Dua stent in the remaining 30 patients.

Addition of the anti-reflux valve on the Dua stent did not compromise the main function of the stent, that is bile drainage as both stents were equally effective in improving liver tests, and complication rates were similar.

Reddy found that the stent with the Dua anti-reflux valve remained functional for a median of 145 days compared to 90 days in those with a standard stent. This resulted in fewer repeat endoscopies for stent changes in patients with the Dua stent. There were six patients in the anti-reflux stent group in whom the stent remained patent for six months and longer compared to only one such patient in the standard stent group.

“In patients with advanced cancers causing bile duct obstruction in whom life expectancy is limited, this difference may translate into fewer procedures to maintain bile duct patency. That means a better quality of life for these cancer patients,” Dua said.

“Our next step is to do electron microscopic analysis of clogged standard and anti-reflux stents to evaluate the role of reflux of intestinal contents in stent clogging. We also hope to look at other uses for this type of stent,” he added

The findings of the research will be published in the May issue of Gastrointestinal Endoscopy journal. (ANI)