Published online before print February 20, 2009, doi: 10.1161/CIRCINTERVENTIONS.108.810507
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Original Articles |
Immunohistochemical Characterization of Neotissues and Tissue Reactions to Septal Defect–Occlusion Devices
From the Department of Pediatric Cardiology and Pediatric Intensive Care Medicine (R.F., T.Q., T.K., T.P., M.S.), Georg-August University, Goettingen, Germany; Pediatric Heart Center (I.M.B.), Justus-Liebig University, Giessen, Germany; Department of Pediatric Cardiology and Congenital Heart Disease (M.V.), German Heart Center Munich at the Technical University, Munich, Germany; and Department of Thoracic and Cardiovascular Surgery (W.R.), Georg-August University, Goettingen, Germany.
Correspondence to Matthias Sigler, MD, Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Georg-August University Goettingen, Robert Koch Strasse 40, D 37099 Goettingen, Germany. E-mail msigler{at}gwdg.de
Received July 28, 2008; accepted January 7, 2009.
Background— We sought to evaluate tissue reactions within and at the surface of devices for interventional therapy of septal defects and to identify antigen characteristics of neotissues.
Methods and Results— Atrial 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 histologic 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 muscle myosin, h-caldesmon, and desmin) beside extracellular matrix components. Neovascularization 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-type 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 neotissues around the implants could be described. Neoendothelialization was seen in all specimens 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 antiplatelet therapy for 6 months after implantation. This time interval should be sufficient to prevent thromboembolic events due to thrombus formation at the foreign surface of cardiovascular implants.
Key Words: heart septal defects • immunohistochemistry • catheterization • occlusion • pathology
CLINICAL PERSPECTIVE
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Circ Cardiovasc Interv 2009 2: 90-96.[Abstract] [Full Text] [PDF]