Immunohistochemical characterization of neotissues and tissue reactions to septal defect-occlusion devices.
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.


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.
Foth
Rudi
R
Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, Georg-August University Goettingen, Robert Koch Strasse 40, Goettingen, Germany.
Quentin
Thomas
T
Michel-Behnke
Ina
I
Vogt
Manfred
M
Kriebel
Thomas
T
Kreischer
Anne
A
Ruschewski
Wolfgang
W
Paul
Thomas
T
Sigler
Matthias
M
D015415:Biomarkers / Q000378:metabolism; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D049109:Cell Proliferation; D003331:Coronary Vessels / Q000378:metabolism / Q000473:pathology*; D020878:Device Removal; D042783:Endothelial Cells / Q000473:pathology; D005337:Fibrin / Q000378:metabolism; D005347:Fibroblasts / Q000473:pathology; D005549:Foreign-Body Reaction / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D006344:Heart Septal Defects, Atrial / Q000628:therapy*; D006345:Heart Septal Defects, Ventricular / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000209:etiology / Q000473:pathology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D055989:Septal Occluder Device; D013997:Time Factors; D017539:Tunica Intima / Q000473:pathology
D015415:Biomarkers; D005337:Fibrin