Three-layered synthetic pericardial substitutes reduce postoperative pericardial adhesions

Background: The development of postoperative pericardial adhesions increases the risk of cardiac reoperations. The purpose of this study was to test a new pericardial substitute (UBE sheet; UBE Industries, Ltd, Tokyo, Japan) that consists of 3 layers, namely, a middle layer of polyester inserted between 2 layers of silicone-urethane copolymer. Methods: Before implantation into the animals, platelet adhesion to the UBE sheet was evaluated in vitro. In the canine model, the UBE sheet (group I; n = 6) was implanted for 3 months. The development of adhesions, epicardial reactions, the shrink ratio of the patch, and macrophage infiltration to the epicardium with histologic examination were evaluated. As a control, an expanded polytetrafluoroethylene sheet (group II; n = 5) was implanted in the same manner. Results: Scanning electron microscopy of the platelets adhered to the sheet showed that the UBE sheet was superior in biocompatibility compared with the expanded polytetrafluoroethylene sheet. In the canine study, group I showed fewer adhesions than group II (median [25th percentile, 75th percentile]: 0.0 [0.0, 0.0] vs 1.0 [1.0, 2.3]; P = .003; Mann-Whitney U test), fewer epicardial reactions (1.75 [1.0, 3.0] vs 3.0 [3.0, 3.0]; P = .034), and a smaller shrink ratio (8.0% [5.5%, 12.4%] vs 31.7% [30.0%, 44.8%]; P = .006). Immunohistologic studies showed fewer macrophage infiltrations (86 [56.8, 139.3] vs 201 [161.0, 276.5] in 3 fields; P = .045) into the epicardium of group I. Conclusions: The new 3-layered pericardial substitute clearly reduced adhesion formation. We concluded that this sheet may cause fewer adhesions and a less severe inflammatory reaction after cardiac surgery, thereby facilitating safe adhesiolysis reoperation.