Use of a novel polyvinyl alcohol membrane as a pericardial substitute reduces adhesion formation and inflammatory response after cardiac reoperation

Background Adhesions may increase the incidence of lethal complications of cardiac reoperations, which account for up to 20% of all open-heart surgeries. Herein, we describe the use of a polyvinyl alcohol membrane (PVAM) as a pericardial alternative and describe its performance during reoperation in a relevant animal model. Methods The PVAM samples were reticulated by electron beam radiation and manipulated into a tube shape. After thoracotomy, the pericardium of Wistar rats was opened to expose the heart. Rats were treated by pushing the heart back into the thoracic cavity (Sham group), sprinkling the epicardium with talcum powder (Talc group), encircling the heart with PVAM (PVAM group), or sprinkling the epicardium with talcum powder before placing the PVAM to encircle the heart (PVAM + Talc group). Animals were recovered for 8 weeks and then euthanized. Macroscopic findings (ie, extent and severity of adhesions) were classified according to a 4-grade adhesion scale. The PVAM was tested for direct and indirect cytotoxicity with Vero cells. The water absorption capability and in vivo calcification after 8 weeks of subcutaneous implantation of the membrane were examined. Data were analyzed by analysis of variance and Bonferroni post hoc tests. Results The PVAM group had lower adhesion scores than the Talc and Sham groups, as well as reduced epicardium thickness and inflammatory cell results, compared with the Talc and PVAM + Talc groups. The PVAM exhibited no direct or indirect cytotoxicity, good water absorption capability (42.4% ± 0.9%), and negligible calcification after 8 weeks (4.42 × 10−3 ± 2.56 × 10−3 percentage of the total mass). Conclusions The PVAM shows promising properties for its potential use as a novel pericardial substitute.