Carag bioresorbable septal occluder (CBSO): histopathology of experimental implants.

AIMS: The aim of this study was to evaluate local biological responses to the partially bioresorbable nonmetal frame Carag bioresorbable septal occluder system in an experimental setting.

METHODS AND RESULTS: A Good Laboratory Practices (GLP) study was performed with implantation of the device into the interatrial septum of 24 German Landrace pigs with follow-up periods of 3, 5, 8 and 15 months (six animals in each group). One non-implant-related death occurred one month after implantation. Histology was obtained by sawing and grinding of the hard-resin embedded specimen after formalin fixation. All occlusion devices were found correctly positioned without any residual shunt at the end of the experiments. Complete endothelialisation could be confirmed histologically in all specimens independent of implantation period. There were only a few lymphocytic infiltrations locally related to the implant materials. Sporadic macrophages and foreign body giant cells were found adjacent to the textile fabric. Resorption of the biodegradable frame material was seen to proceed with implantation time.

CONCLUSIONS: This is the first report on histopathology of a septal defect occluder with a bioresorbable filament structure in vivo which is already in clinical use. Good biocompatibility was demonstrated with documentation of timely degradation and substitution of the polymer material by fibromuscular cells and extracellular matrix components.