Animal experimental implantation of an atrial septal defect occluder system

Abstract

Objective-To establish the implantation technique for the atrial septal defect occluder system (ASDOS) device in an experimental animal model and to determine long term mechanical stability of the device and its in vivo properties in terms of biocompatibility and tissue reaction. Materials and methods-An atrial septal defect was created and the device implanted in 17 pigs (mean weight 30 kg). The implantation technique was refined and modified because of initial technical and anatomical complications during nine acute pilot studies. The technique proved to be feasible in eight subsequent survival studies. Four pigs were electively killed three months after implantation (group 1). The remaining four pigs were killed six months after implantation (group 2). Results-Necropsy showed all devices were embedded in soft tissue three months after implantation. Microscopic examination of atrial septal tissue showed an acute granulomatous inflammatory reaction in group 1 and fibrosis in group 2. The intensity of the inflammatory reaction around the device was clearly milder in group 2, indicating a decline in the inflammatory response with time. Clinical and biochemical investigations indicated acceptable biocompatibility of the device. Conclusion-The implantation technique for the ASDOS device in a chronic pig model has been established. Biocompatibility of the device was acceptable. (Heart 1998;80:606-611)

Biocompatibility of septal defect closure devices

“…[2][3][4][5][6][7][8] Besides individual case reports, 13 14 there is only one published series in humans describing the healing response to the historical clampshell device used for various defect closures performed during regulatory trials. 1 This device was withdrawn from the market owing to a high rate of metal arm fractures 15 16 and-following a redesign of the framework-replaced by the Cardioseal device in 1996 and its self-centring modification, the Starflex device in 1998.…”

“…Follow-up periods in vivo after device implantation in these studies usually range between 3 months and 2 years because of the necessity to obtain timely results from experiments which are highly demanding with regard to time, costs and effort. [2][3][4][5][6][7][8] This relatively short follow-up period with regard to local tissue response and biocompatibility contrasts with the expected lifelong implant persistence of some 70-80 years in young children.…”

Interventional Atrial Septal Defect Closure Using a Totally Bioresorbable Occluder Matrix

“…Studies in experimental animals have characterized the histologic features and time course of the healing response and tissue ingrowth onto the device after implantation (1)(2)(3)(4)(5)(6)(7).…”

Is device closure for direct access valved stent implantation safe?

“…In yet another animal experiment, ASD was occluded with ASDOS device [22]. The pathomorphological changes referred to by authors as chronic changes, appeared in pigs after 3 and 6 months following the implantation.…”