In vivo hemodynamic, histologic, and antimineralization characteristics ofthe mosaic bioprosthesis

Background. Performance of bioprosthetic valves is limited by tissue degene ration due to calcification with reduced performance and longevity. The Mos aic bioprosthetic valve (Medtronic Heart Valves, Inc, Minneapolis, MN) comb ines zero pressure fixation, antimineralization properties of alpha -amino oleic acid (AOA), and a proven stent design. We tested the hypothesis that AOA treatment of Mosaic valves improves hemodynamics, antimineralization pr operties, and survival in a chronic ovine model. Methods. Mitral valves were implanted in juvenile sheep with Mosaic valves with AOA treatment (n = 8) or without AOA treatment (non-AOA, n = 8), or Ha ncock I (HAN, n = 4) tissue valves, and explanted at 20 postoperative weeks . Results. Survival was equivalent in AOA and non-AOA (140 +/- 0.4 and 129 +/ - 30 days): but was significantly less in HAN (82 +/- 35). Leaflet calcium (mu gCa/mg tissue) was less in AOA (9.6 +/- 13.9; p < 0.05 versus non-AOA a nd HAN) than non-AOA (96.3 +/- 63.8) and HAN (130.8 +/- 43.2). Explant valv e orifice area (cm(2)) was significantly preserved in the AOA group compare d with the non-AOA group (1.5 +/- 0.7 vs 0.8 +/- 0.3; p < 0.05 versus non-A OA and HAN). Conclusions. We conclude that AOA treatment of Mosaic valves reduces leafle t calcification and valve gradient in juvenile sheep, and that the Mosaic d esign and fixation features may offer survival advantages that must be conf irmed in extended trials. (Ann Thorac Surg 2001;71:92-9) O 2001 by The Soci ety of Thoracic Surgeons