Comparative electron microscopic study of bovine, porcine and human parietal pericardium, as materials for cardiac valve bioprostheses.

Light, scanning and transmission electron microscopy were used in the comparison of bovine, porcine and human parietal pericardium. Bovine pericardium is widely used for heart valve bioprosthesis, is thicker than the other two, and has more coarse connective tissue fiber components, whereas porcine pericardium possesses relatively larger quantities of fat cells in regular layers. Human tissue is thinner than either the bovine or porcine parietal pericardium and its mesothelium seems less delicate. The human tissue, being thinner, may provide a source of materials for valves with significant hemodynamic characteristics. Such material might be used to produce small diameter valves directed towards younger patients. Though the literature does not mention its usage, porcine pericardium is of intermediate thickness and it too may serve in the future as a construction material for valve bioprostheses.