Endurant undergoes first human implant.
Medtronic’s next-generation stent graft, for the treatment of abdominal aortic aneurysms (AAA), has been implanted for the first time in a human patient. The announcement was made by Professor Hence JM Verhagen, Professor and Chief of Vascular Surgery, University Medical Center Rotterdam, Erasmus Medical Center Rotterdam, The Netherlands, at this year’s VEITHSymposium in New York. The Endurant aortic abdominal aneurysm stent graft has a new design and flexibility to treat more difficult anatomies and an outer diameter profile to access and track smaller iliac arteries. In particular, Verhagen highlighted the ’M’ shaped promixal stent for enhanced neck conformability and increased flexibility, designed for up to 75° angulation and a design that allows for continuous flow in highly-angulated situations. “This stent graft really is a next-generation device. It incorporates new features that have been specifically designed to address a patient population with highly-angulated necks,” Verhagen told Vascular News. “The first implant was a success and we look forward to being able to presenting 30- days results in 2008.” Additional design features include a new suprarenal stent, a radial force similar to the Talent AAA, a short sealing zone, short stent length, electropolished stents throughout the device and an exoskeleton. The suprarenal stent incorporates acute fixation for greater flexibility by reducing longitudinal columner strength allowing migration resistance. To compensate for the reduced columner strength, specially designed anchoring pins have been incorporated onto the Endurant graft to prevent migration. Another characteristic includes a onepiece design (no soldering) to reduce anchor breakage. It also has additional strength built at stress spot between suprarenal stent graft material. Verhagen claims the device incorporates proven, durable materials, such as nitinol stents and polyester graft material (from the original AneuRx stent graft), with over ten years of clinical use. This High Density polyester graft material that has a greater durability and less porosity then a monofilament polyester graft material.
Delivery and deployment
The delivery system is based on the currently used Xcelerant delivery system and incorporates improved flexibility and trackability. A hydrophilic coating on the outside of the catheter reduces friction forces by over 90%. The system also has the ability to position partially deployed stent graft proximally and distally. In addition, the system has a specially adapted mechanism for the controlled release of the suprarenal anchoring pins. The system also has strategically placed markers to facilitate accurate deployment. Specifically, the graft has an ’e’ marker to identify the contralateral gate and a flow divider for accurate contralateral limb placement, and a contralateral gate ring marker assists with cannulation. The stent graft is currently being assessed in a prospective, multi-centred European trial, with two study arms; low/moderate angulated necks (>10mm proximal stent length, <60 degrees infrarenal angulation) and high angulated necks (>15mm proximal stent length, <70 degrees infrarenal angulation). The primary endpoints of the study are clinical success (30-day all cause mortality) and technical success (delivery and deployment success). The seconday endpoints (at 30 days and 12 months) include type I and type III endoleaks, graft infection, thrombosis or occlusion, loss of device integrity, conversion to open repair and aneurysm rupture. Medtronic expects to receive the CE mark for the Endurant stent graft in the summer of 2008.