Background and aim of the study: Photo-oxidation treatment of porcine stentless bioprostheses (Photofix) was compared with glutaraldehyde fixation, with either AOA (Freestyle valve) or Tween-80 (Edwards Prima Plus valve).
Methods: Six valves of each type were implanted in juvenile sheep, in the pulmonary position. Valves were explanted after three or six months and examined macroscopically, by X-radiography, and by light and transmission electron microscopy. Calcium content was determined by atomic absorption spectrometry.
Results: The cusps of all valves were free of calcification, and had normal histology and function. Calcium contents (median +/- IQR) were 0.63+/-0.45, 0.73+/-1.46 and 0.46+/-1.42 microg/mg for the Photofix, Freestyle and Prima Plus valves, respectively (p = NS). Calcium contents of the aortic wall portions were 0.71+/-1.27 (Photofix), 10.78+/-77.22 (Freestyle) and 28.70+/-66.53 (Prima Plus) (p <0.05 for Photofix versus Freestyle or Prima Plus).
Conclusion: Photo-oxidation of a porcine stentless valve prevents calcification not only in the cusps, but also in the aortic wall portion.