Rapid and untypical calcification of the Sorin pericarbon stentless pericardial xenograft in a child. 
Stentless valves are designed to reduce mechanical stress and it is hypothesized that degeneration is reduced.  We report early calcification of a Sorin pericarbon stentless pericardial xenograft in aortic position leading to valve failure 2 years after valve replacement in an 11-year-old boy.  Morphological evaluation of the explant revealed severe calcification of the leaflets in a uniformly distributed pattern.  Positive staining for non-collagen bone matrix proteins was found in the organic matrix of calcific deposits and in infiltrated macrophages.  The stentless design of the Sorin valve does not mitigate calcification and therefore cannot be recommended for children.