Matthias Sigler, Katja Eildermann, Theodor Tirilomis*, Heike Schneider, Rudi Foth, Thomas Paul
Pediatric Cardiology and Intensive Care, *Thoracic and Cardiovascular Surgery, Georg-August-Universität Göttingen, Germany
DOI: http://dx.doi.org/10.18053/jctres.aecvp2016.017
Background: The field of interventional therapy for congenital heart disease is rapidly developing. However, knowledge about biocompatibility of metallic and/or textile implants is limited. Methods: We studied and compared tissue reactions of >100 cardiovascular implants after surgical removal (vascular stents, valved stent grafts, septal defect occluder, occluder of the arterial duct) with an implantation time of a few hours to 15 years. Explants were worked up using a uniform protocol with methyl methacrylate embedding after fixation in formalin. Histology and immunohistochemistry was performed after sawing and grinding of the hard resin blocs. Results: After initial fibrin clotting at the implant surface, ingrowth of fibromuscular cells with antigen characteristics of vascular smooth muscle cells was seen in a material-dependent time pattern in stents (intimal hyperplasia) as well as within occlusion devices. Immunohistochemistry revealed the growth of a monolayer of endothelial cells on the intravascular surface of the implants as early as 14 to 20 days after implantation. Different types of inflammatory reactions (granulocytic, lymphocytic, macrophages/foreign body reaction) could be identified at the implant/tissue interface. Lymphocytes and foreign body giant cells were detected up to 15 years after implantation. Explants with significant chronic inflammation tended to show more calcifications. Conclusions: Biocompatibility screening revealed regular ingrowth and endothelialization of most explants but persisting inflammatory reactions after implantation of interventional devices within the cardiovascular system. Calcifications seem to coincide with inflammatory reactions. Our results emphasize the importance of advances in the development of biodegradable implants.
Email: msigler@gwdg.de
