A New Pan-Nitinol Occluder for Transcatheter Closure of Ventricular Septal Defects in a Canine Model

Background: The Amplatzer ventricular septal defect (VSD) occluder has a fixed stainless steel pin bottom protruding out of the surface at the center of the discs on both sides. Theoretically, this protruding bottom may interfere with epithelialization or, in some cases, cause thrombosis. Objective: To evaluate a new type of pan-nitinol VSD occluder without the protruding stainless steel pin bottom on both sides in a canine VSD model designed to ensure safety, effectiveness, and feasibility. Methods and Results: VSDs were successfully created by transseptal ventricular septal puncture with a Brockenbrough needle and dilation with an 8-mm-diameter balloon via the right jugular vein in 9 out of 12 canines. The new type VSD occluder was successfully implanted in 8 of the 9 modeled canines. No procedure- or device-related complication was observed. Transthoracic echocardiography and MRI 2 months after device implantations showed that there was no device dislocation or heart valve dysfunction in 6 of the 8 tested canines. In addition, gross and pathological examinations 3-6 months after implantation showed no corrosion of the devices or serious inflammatory reactions in the modeled animals. Complete endothelialization was seen over the surface of the discs. Conclusions: The new pan-nitinol VSD device can be successfully implanted in a canine VSD model via a transcatheter approach featuring high success rate, low risk of procedure-related complications, and sound biocompatibility. The result suggests that this new VSD occluder could be used safely in future clinical trials for further test. (J Interven Cardiol 2009;22:191-198).