EFFECT OF THE SUTURE ON THE DURABILITY OF BOVINE PERICARDIUM USED IN CARDIAC BIOPROSTHESES

Our study of the different biomaterials used in the construction of bi ological cardiac prostheses has shown it to be of vital importance tha t the physical properties of the tissue and of the suture that anchors it to the rigid polymeric support are compatible. By means of dynamic tests, we have determined the fatigue curve in sutured bovine pericar dial tissue, expressed by the equation log y = 1.27 +/- 0.18 - (0.26 /- 0.05) log t, where y is the initial fatigue stress (MPa) and t is t he time (min) it takes to achieve permanent deformation of the tissue. By applying this correction, we determine a set of values for stress- time which, when compared with those obtained with a non-sutured sampl e, reveal a significant fall in this ratio and, thus, a decrease in th e durability. The use of suture threads of lesser elasticity than the pericardium may play an important role in reducing the durability of t he bioprosthesis constructed with these materials.