on February 20, 2009
Published online before print February 20, 2009, doi: 10.1161/CIRCINTERVENTIONS.108.810507
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Original Article |
Immunohistochemical characterization of neo-tissues and tissue reactions to septal defect occlusion devices
1 Georg-August University;
2 Justus-Liebig University;
3 German Heart Center Munich at the Technical University
4 E-mail: msigler{at}gwdg.de
Background—To evaluate tissue reactions within and at the surface of devices for interventional therapy of septal defects and to identify antigen characteristics of neo-tissues.
Methods and Results—Atrial septal defect or ventricular septal defect occlusion devices (Amplatzer n = 7; Cardioseal/Starflex n = 3) were processed using a uniform protocol after surgical removal from humans (implantation time 5 days to 4 years). Devices were fixed in formalin and embedded in methylmethacrylate. Serial sections were obtained by sectioning with a diamond cutter and grinding, thus saving the metal/tissue interface for histological evaluation. Immunohistochemical staining was performed using conventional protocols. Superficial endothelial cells stained positive for von Willebrand factor. Within the newly formed tissues, fibroblast-like cells were identified with a time dependent expression of smooth muscle cell maturation markers (smooth muscle actin, smooth muscel myosin, h-caldesmon, desmin) beside extracellular matrix components. Neo vascularization of the newly formed tissues was demonstrated with the typical immunohistochemical pattern of capillaries and small vessels. Inflammatory cells could be identified as macrophages (CD68 +) and both T- and B-type lymphocytes (CD3 +, CD79 +).
Conclusions—This is the first presentation of results from serial immunohistochemical staining of a collection of explanted human septal occlusion devices. A time dependent maturation pattern of the fibroblast-like cells in the neo-tissues around the implants could be described. Neoendothelialization was seen in all specimen with implantation times of 10 weeks or more. The time course of neoendothelialization as seen in our study further supports the clinical practice of anticoagulant or anti platelet therapy for 6 months following implantation. This time interval should be sufficient to prevent thromboembolic events due to thrombus formation at the foreign surface of cardiovascular implants.
Key Words: catheterization • heart septal defects • immunohistochemistry • occlusion • pathology
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