Refinement of the alpha aminooleic acid bioprosthetic valve anticalcification technique.
BACKGROUND
Aminooleic acid treatment has been demonstrated to prevent porcine valve calcification and to protect valvular hemodynamic function. Initial enthusiasm was tempered by histologic studies of these AOA valves, which showed cuspal hematomas, structural loosening, and surface roughening. This prompted a systematic review of the AOA treatment process. Unsolubilized particles of alpha aminooleic acid present in the treatment solution were identified as the cause of mechanical abrasion of valve cusps during processing. These particles were eliminated with a revamped protocol, which included filtration of the AOA solution before valve preparation.


METHODS
Porcine aortic valve cusps treated with this modified AOA protocol (AOA II) were studied in a rat subdermal implant model of mineralization. A juvenile sheep trial was then used to confirm the antimineralization effects of AOA II on glutaraldehyde-fixed porcine aortic roots in a circulatory model of accelerated calcification.


RESULTS
Retrieved AOA II-treated cusps from the subdermal model were markedly less calcified than control cusps (AOA II, 1 +/- 0, 17 +/- 4, 23 +/- 6, and 17 +/- 10 versus control, 189 +/- 14, 251 +/- 16, 250 +/- 14, and 265 +/- 10 mg calcium/mg sample at 4, 8, 12, and 16 weeks, respectively; p < 0.0001). Morphologic examination of the AOA II cusps of the valves retrieved from the sheep demonstrated freedom from the structural loosening, surface roughening, and hematoma formation that had limited the utility of the original AOA preparation technique. Cusps from AOA II-treated porcine roots had significantly less calcium than control cusps (AOA II, 5.5 +/- 3.0 mg/g; control, 91.2 +/- 19.5 mg/g; p = 0.0004). The aortic walls had similar levels of calcification (AOA II, 156 +/- 73 mg/g; control, 159 +/- 10 mg/g; p = not significant).


CONCLUSIONS
These data suggest that the modified AOA technique warrants further evaluation as an antimineralization treatment for glutaraldehyde-fixed porcine bioprostheses.
Gott
J P
JP
Carlyle Fraser Heart Center, Crawford Long Hospital of Emory University, Emory University School of Medicine, Atlanta, Georgia 30365, USA.
Girardot
M N
MN
Girardot
J M
JM
Hall
J D
JD
Whitlark
J D
JD
Horsley
W S
WS
Dorsey
L M
LM
Levy
R J
RJ
Chen
W
W
Schoen
F J
FJ
Guyton
R A
RA
D000818:Animals; D001705:Bioprosthesis; D002114:Calcinosis / Q000517:prevention & control*; D006350:Heart Valve Prosthesis; D008297:Male; D008954:Models, Biological; D009829:Oleic Acids / Q000627:therapeutic use; D011183:Postoperative Complications / Q000517:prevention & control*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012756:Sheep
D009829:Oleic Acids; C088318:2-(amino)oleic acid