Behaviour of the bovine pericardium used in cardiac bioprostheses when subjected to a real fatigue assay.

Abstract

The behaviour of bovine pericardium was studied using a fatigue assay. Twenty-three samples were assayed, maintaining the preset initial stress and measuring the time it took for the onset of load loss due to permanent deformation. The results indicated a mathematical relationship defined by the expression: log y = 1.3 - 0.211 log t, where y is the fatigue stress (MPa) and t the duration of the assay. The correlation coefficient was 0.948 (P < 0.001). The safety coefficient of the material diminished significantly as the period of time during which it was subjected to fatigue increased. The theoretical durability of the tissue was much greater than the real durability of the prostheses, which is determined by unsolved problems such as calcification and those derived from suture-related cutting.