Evidence of mitigated calcification of the Mosaic versus Hancock Standard valve xenograft in the mitral position of young sheep.
OBJECTIVE
Durability remains the main problem of all bioprosthetic valves, and calcification is the major cause of failure. New tissue treatment processes are expected to reduce mineralization. A comparative animal study was undertaken to evaluate the behavior of a new-generation porcine bioprosthesis in contrast with a first-generation porcine bioprosthesis. The primary goal was to evaluate the efficacy of alpha-amino-oleic acid as an anticalcification treatment.


METHODS
Seventeen Targhee sheep (aged 4.5-7 months) had a mitral valve replacement with a Mosaic or Hancock Standard. The animals were followed up to 20 weeks (144.1 +/- 4.0 days vs 144.3 +/- 8.2 days) and then euthanized as scheduled. After gross examination, the explants were radiographed for the presence of calcification. The central portions were preserved for histologic examination, and the remainder of the sample was analyzed for quantitative calcium content by atomic absorption spectroscopy.


RESULTS
Four Mosaic sheep were excluded because of perioperative surgical mortality. The remaining 13 were enrolled in the study (9 Mosaic and 4 Hancock Standard). The mean calcium content was 1.97 +/- 2.21 microg/mg tissue weight for Mosaic versus 8.36 +/- 4.12 microg/mg for Hancock Standard valves (P < .01). Mild fibrous tissue overgrowth and fibrinous lining were observed regardless the xenograft type.


CONCLUSIONS
The low level of calcification in the Mosaic versus Hancock Standard xenografts confirms the efficacy of alpha-amino-oleic acid treatment in mitigating mineralization. A longer durability is expected with the clinical use of the Mosaic porcine valve.
Weber
Patricia A
PA
International Heart Institute of Montana Foundation at Saint Patrick Hospital and Health Sciences Center and The University of Montana, Missoula, Mont, USA.
Jouan
Jérôme
J
Matsunaga
Akira
A
Pettenazzo
Elena
E
Joudinaud
Thomas
T
Thiene
Gaetano
G
Duran
Carlos M G
CM
D000818:Animals; D001705:Bioprosthesis; D002114:Calcinosis; D002317:Cardiovascular Agents / Q000494:pharmacology; D004195:Disease Models, Animal; D006349:Heart Valve Diseases; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D008943:Mitral Valve; D008955:Models, Cardiovascular; D019301:Oleic Acid / Q000494:pharmacology; D009829:Oleic Acids / Q000494:pharmacology; D012756:Sheep
D002317:Cardiovascular Agents; D009829:Oleic Acids; D019301:Oleic Acid; C088318:2-(amino)oleic acid