Effects of glutaraldehyde concentration and fixation time on material characteristics and calcification of bovine pericardium: implications for the optimal method of fixation of autologous pericardium used for cardiovascular surgery.

Objectives: Autologous pericardium, which is widely used in the field of cardiovascular surgery, is usually fixed with glutaraldehyde (GA) to improve handling and provide biomechanical stability. However, an optimal method of GA fixation of autologous pericardium is not known. The objective of this study was to evaluate the effects of GA concentration and fixation time on material characteristics and calcification of bovine pericardium.
Methods: Bovine pericardial tissues were fixed with different concentrations of GA (0.3, 0.4, 0.5 and 0.6%) for different exposure times (10 and 20 min). Material characteristics of the fixed tissues were assessed by mechanical test, thermal stability test and pronase test. The tissues were subcutaneously implanted into 3-week-old rats for 2 months, and the calcium contents of the explanted tissues were measured. Differences between the groups were evaluated by two-way analysis of variance.
Results: Differently treated tissues showed no significant differences in tensile strength. The mean elongation at break of the pericardial tissues fixed with 0.5 and 0.6% was significantly higher compared with 0.3 and 0.4% when fixed for 20 min. The mean elongation at break of the pericardial tissues fixed for 20 min was significantly higher compared with 10 min when fixed with 0.5 and 0.6%. Thermal stability test revealed significantly higher mean shrinkage temperature of the pericardial tissues fixed with 0.6% compared with lower concentrations irrespective of fixation time. The mean shrinkage temperature of the pericardial tissues fixed for 20 min was significantly higher compared with 10 min irrespective of GA concentration. Pronase test revealed significantly lower mean percent remaining weight of the pericardial tissues fixed with 0.3% compared with higher concentrations irrespective of fixation time. The mean percent remaining weight of the pericardial tissues fixed for 20 min was significantly higher compared with 10 min irrespective of GA concentration. The mean calcium content of the pericardial tissues fixed with 0.6% was significantly lower than that of the pericardial tissues fixed with 0.4% irrespective of fixation time. Conclusions: Fixation of bovine pericardium with 0.5 and 0.6% GA for 20 min produced superior results with regard to material characteristics (mechanical properties, degree of fixation and resistance to enzymatic degradation) and postimplantation calcification. These results may have implications for optimal fixation of autologous pericardium used for cardiovascular surgery.