Reduction in experimental pericardial adhesions using a hyaluronic acid bioabsorbable membrane

Various materials have been suggested for pericardial closure following cardiac surgery to limit postoperative adhesion formation. Unfortunately, these devices have caused difficulties with infection, calcification, and epicardial scar formation. A bioabsorbable membrane with a short in-vivo persistence time, acting as a barrier to adhesion formation until mesothelial healing occurs, might obviate many of these problems. We examined the efficacy of a bioabsorbable membrane containing hyaluronic acid in the prevention of experimental pericardial adhesions; hyaluronic acid solutions have been shown experimentally to reduce adhesions following abdominal, orthopedic and cardiac surgery. Eleven dogs underwent sternotomy and pericardiotomy followed by 2-h protocol of desiccation and abrasion of pericardial and epicardial surfaces. In five dogs, the epicardial surfaces were covered with the test material, followed by pericardial and sternotomy closure. Six dogs served as controls. All animals underwent resternotomy 8 weeks after surgery; intrapericardial adhesions were graded on a severity scale (0-4). The test animals (mean adhesion score 1.4 +/- 0.5) had either no adhesions or filmy, avascular adhesions easily taken down with blunt dissection. In contrast, dense adhesions were found in the control animals (mean score 3.2 +/- 0.4), frequently obscuring tissue planes and epicardial anatomy. Use of the bioabsorbable membrane significantly reduced adhesion formation (test vs control, P < 0.001, Mann-Whitney test). We conclude that a hyaluronic acid membrane reduces postoperative pericardial adhesions in this canine model, and that the use of a bioabsorbable barrier in the prevention of pericardial adhesions warrants further investigation.