Repeat surgery occasioned by the incompetence of the primary tissue in biological prostheses

: The authors analyse the causes of repeated operations on 42 among a group of 157 patients with implanted biological cardiac valve prostheses and a postoperative follow-up period of 3.5 to 13 years. The main cause of dysfunction of biological prostheses is calcification which develops mostly in xenopericardial valves irrespective of their localization. Detachment of the cusps from the frame and their destruction is characteristic of allogeneic prostheses and those formed from the dura mater. Dysfunction of bioprostheses in the tricuspid position develops much later.