[Surface changes of the pulmonary valve following pulmonary valve xenotransplantation in the descending aorta. An experimental study in dogs].

Upon implantation in the descending aorta, glutaraldehyde-conditioned pulmonary valves (n = 46) are immediately covered by a protein layer, followed by a fibrinous layer. Two to thirty minutes later platelets, WBCs, macrophages, and microthrombi are incorporated into the valve's surface. After 3 weeks the first collagen fibers appear on the surface and slowly build a collagen layer that grows toward the free edge. These changes are very similar to the surface changes of bioprostheses implanted in humans.