Calcification characteristics of porcine stented valves in a juvenile sheep model

Background. Different antimineralization treatments of stented porcine bioprostheses were evaluated: ethanol (Epic), alpha -amino-oleic acid (AOA) (Mosaic), and sodium dodecyl sulfate (SDS) (Hancock II). A nontreated, glutaraldehyde-fixed valve (Labcor) served as control. Methods. For each treatment, six valves were implanted in juvenile sheep in the pulmonary position. Valves were explanted after 3 and 6 months and examined macroscopically, by roentgenogram and light and transmission electron microscopy. Calcium content (mug/mg) was determined by atomic absorption spectrometry. Results. The Labcor valves revealed small calcium deposits in the cusps, although calcium content remained low (median value 0.4 +/- 0.8 mug/mg). SDS did not prevent cusp calcification as assessed by histology and calcium content measurement, which was higher than in all other valves: 1.9 +/- 4.6 mug/mg (p < 0.05). Cusp retraction and rupture were occasionally found in the Hancock. The Mosaic and Epic valves showed no cusp calcification and had low calcium contents (0.3 +/- 2.4 mug/mg and 0.7 +/- 0.6 mug/mg, respectively). Epic showed less pannus formation, but had hematoma or iron staining in the cusps. Conclusions. SDS is inefficient as an antimineralization treatment, in contrast to ethanol or AOA. Cusp hematoma after ethanol treatment needs further investigation. (C) 2001 by The Society of Thoracic Surgeons.