7256 Multicenter randomized comparative trial of the new gianturco spiral z-stent compared to wallstent: study design and preliminary report of the zoom study.

Abstract

Introduction: Evaluation of long-term patency for devices introduced for the treatment of extrahepatic malignant biliary obstruction require comparative trials in view of the high degree of variability among patients. Reported stent patencies of newly introduced products are frequently not confirmed in clinical practice (Gastrointest Endosc 1999:49:700(A)). New products, particularly those involving high risk interventions and high cost, should be studied carefully in multicenter trials to gain consensus as to their clinical utility.We propose to study the new spiral stent for malignant obstruction compared to the other metal stent (ZOOM). Study Goal: All our participating centers have obtained IRB approval to offer appropriate patients a randomized option of a standard uncoated Wallstent (Microvasive,Watertown, MA) or a new stainless steel uncoated Gianturco spiral Z-stent (Wilson-Cook, Winston-Salem, NC) for palliative treatment of malignant extrahepatic biliary obstruction. All strictures must be 2 cm or more below the bifurcation and patients must be in good physical condition as measured by a Karnofsky score of 60 or higher (Requires occasional care for most needs). Patients with prior temporary plastic stents can be accepted providing they do not show evidence of occlusion or cholangitis and have appropriate Karnofsky's scores. Patients will then have serum bilirubins measured at 1 month and clinical follow-up on a monthly basis. Every effort will be made to determine the cause of stent occlusion. A study of sufficient power to detect a 20% difference in results has been calculated to require 200 patients to be enrolled. Preliminary Results: 24 patients have been randomized after successful guidewire placement through their malignant obstructions. 12 patients have received Wallstents and 12 patients have received spiral Z-stents. There have been no initial failures of stent placement. All patients have achieved initial biliary drainage. More extensive data of initial stent placement and initial drainage will be forthcoming as patients are enrolled with long-term patency data anticipated in the next 1-2 years. Conclusion: A large randomized controlled study of the newly introduced uncoated Gianturco spiral Z-stent is underway to compare procedural success, initial drainage and, most importantly, long-term patency. Such trials are needed to permit the most appropriate employment of new devices.