Cook Medical is touting a recent study that compares the effectiveness of the firm’s Zilver Biliary Stent to the most commonly used device, the Wallstent from Boston Scientific. Essentially, the conclusion of the international multi-center study, published in Gastrointestinal Endoscopy, is that the two stents have very similar performance (patency) characteristics, both exhibiting stent occlusions in the low 20% of cases. (The Zilver stent in a smaller 6mm diameter was found to exhibit a higher, 39.1%, rate of occlusion, hence that arm of the study was closed earlier than anticipated.)
The MOZART study included a total of 241 patients in nine centers in the U.S., Canada and Europe who presented with malignant biliary obstructions – a complication associated with several forms of cancers – in which the bile ducts of the liver become blocked by tumors. Biliary obstructions or strictures impair liver function and cause a range of symptoms including abdominal pain, nausea, vomiting, fever and fatigue. The blocked ducts can be opened using stents inserted endoscopically that expand upon deployment. Plastic stents are cheaper than metal for this purpose, but data suggest that plastic stents occlude more readily when compared to SEMS, necessitating repeat procedures. In fact, SEMS have proved more robust and cost-effective in many clinical settings.
According to the MOZART study, the 6-mm SEMS demonstrated a higher occlusion rate than the 10-mm SEMSs; therefore, the study agreed to close this arm to further patient entry and continue to follow the exiting enrolled patients. The remaining 10-mm SEMS patients revealed equal patency among SEMS.
The two biliary stents in the MOZART study differ significantly in design, materials and mechanism of expansion, but achieved equal patency by several measures: for both, fewer than a quarter became occluded after placement over the life of the study. Treating physicians, who had more experience with Boston Scientific’s stent, reported the ease of positioning of the Zilver during the study.
Cook Medical’s Zilver Biliary Stent is the first stent of its kind made of flexible laser-cut nitinol tubing. Nitinol, which is inherently kink-resistant, allows Zilver to conform to the ductal wall while providing reliable patency. Through the interlocking design construction, Zilver’s stent ends are atraumatic, potentially reducing the risk of ulceration or perforation. Its non-foreshortening design gives precise accuracy in placement; potentially reducing instances of migration and the need for repeat procedures. Additionally, four gold radiopaque markers at each end of the stent provide greater fluoroscopic visualization and exacting placement.
Benefits and Offerings of the Zilver 635:
Zilver 635 has the markets only 6 FR introducer, the optimal platform for hilar and bifurcation stenting; Utilizes Cook’s proprietary Flexor coil-reinforced introducer technology: a truly unique material that has excellent pushability and flexibility while providing a distinct advantage in stent placement due to its kink resistance; The only system in the world that allows two stents to be placed simultaneously through a standard 4.2-mm channel duodendoscope, thereby increasing procedural efficiency; Includes a shelf-less tip design to ensure smooth withdrawal of the introducer through the deployed stent.
Press release: First and Only International Study of its Kind Shakes up Metal Biliary Stent Market…
Product page: Zilver 635…
Abstract in Gastrointestinal Endoscopy: Comparative performance of uncoated, self-expanding metal biliary stents of different designs in 2 diameters: final results of an international multicenter, randomized, controlled trial