Histologische Analyse einer Serie chirurgisch explantierter Okkluder für den interventionellen Verschluss von Atriumseptumdefekten

Histological analysis of a series of surgically explanted occluders for the interventional closure of atrial septal defects

von Ann-Katrin Grams geb. Schmidt
Dissertation
Datum der mündl. Prüfung:2021-10-28
Erschienen:2021-10-26
Betreuer:Prof. Dr. Matthias Sigler
Gutachter:Prof. Dr. Matthias Sigler
Gutachter:Prof. Dr. Hassina Baraki
Zum Verlinken/Zitieren: http://dx.doi.org/10.53846/goediss-8846

 

 

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Zusammenfassung

Englisch

Devices for interventional atrial septal defect closure are meant to remain in patient’s bodies for several years. Up until now little is known about the long-term biocompatibility. The main goal of this work was the macroscopical and histological analysis of 45 occluder-devices with particular focus on neoendothelialisation, thrombusformation and -persistence, the reaction of metallic structures and the environment as well as cellular immune response. For this work 45 devices, implanted for a period between one day and 20.4 years, were examined. They were surgically explanted between 2001 and 2019. Residual shunting was the most common indication for device removal. After the explantation the tissue blocks including the devices were prepared and fixed in methylmethacrylat, a resin. The resin blocks were then sliced, grinded and stained according to the techniques of Richardson and von-Kossa A complete neoendothelialisation of the devices was seen after three months in vivo. Seven devices showed thrombusformation or excessive tissue on the surface, mostly localised in the left atrium. Consequently, an increasing risk of embolic strokes as well as myocardial infarction demonstrate the importance of a consistent anti-platelet therapy after interventional ASD-closure. In contrast, the formation of thrombotic material inside the devices is a wanted effect to achieve an immediate closure of the defect. Soon after the implantation, the initial thrombotic material was replaced by structured and fibre-rich tissue. This tissue reorganisation initiated by immigrated fibroblasts, seemed to begin in the device periphery. After the implantation, the cellular immune response was characterised by granulocytes for approximately two months, later it was dominated by lymphocytes. The lymphocytic infiltration persisted even in the longest-term devices as a sign of chronic inflammation. Reason for a chronic inflammation may be the release of nickel ions from metallic structures of the devices or the foreign surface itself. In contrast to metallic parts, the synthetic patch-fibres induced a pronounced deposition of macrophages and subsequently, after about two months, multinucleated foreign body giant cells.  These types of inflammatory reaction, lymphocytic infiltration and the presence of foreign-body giant cells, were observed even in the longest-term devices and, in addition, showed a highly variable interindividual occurrence. All examined devices in this work were explanted because of medical indications following unsatisfactory results. Consequently, these results may not allow a conclusion to be drawn to devices with best clinical results. Additionally, this histopathological analysis shows a limited number of devices. For the future, it would be of great interest to examine every explanted device to obtain more knowledge about the processes in vivo. 
Keywords: biocompatibility screening of ASD occluder devices; atrial septal defect; histological analysis of atrial septal defect occluder devices
 
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