Comparison of Two Percutaneous Atrial Septal Defect Occluders for Device Healing and Nickel Release in a Chronic Porcine Model

Figure 3

Histological images with Richardson Blue staining showing sequential tissue organization of device coverage after implantation. (A–C) Right atrial disk of an ASO 1 month after implant, showing a thin coverage of the device ((A), red circle) associated with an inflammatory reaction including mononuclear directed toward the nitinol wires (B) and foreign body giant cells (black arrows) in contact with the polyester fibers (C). (D–F) Right atrial disk of a Hyperion occluder 3 months after implant; the granulation tissue is less inflammatory but more fibrous (D, E) with a more organized and vascularized pattern (black asterisk, (F)). We can observe an integration of nitinol wires (F) associated with a superficialneo-endothelial layer (black arrows, (D, E)). ASO: Amplatzer septal occluder; N: nitinol; : polyester fibers.