Calcification modelling in artificial heart valves.

This study has examined a range of methods of studying the calcification process in bovine pericardial and polyurethane biomaterials. The calcification methods include static and dynamic, in vitro and in vivo tests. The analytical methods include measurement of depletion rates of calcium and phosphate from in vitro calcifying solutions, analysis of tissue contents of calcium, histological staining of tissue sections for calcium, X-ray elemental analysis, by scanning electron microscopy, of calcium and phosphorus distributions over valve leaflets calcified in vitro under dynamic conditions. Bovine pericardium, in all test settings, calcified to a much greater degree than polyurethane biomaterials. Polyurethane extracts calcified to a greater degree than bulk polyurethanes. The test protocol used allows progress through increasingly demanding calcification tests, with the possibility of eliminating unsuitable materials with tests of limited complexity and expense.