I. Vesely et al., THE HYBRID XENOGRAFT AUTOGRAFT BIOPROSTHETIC HEART-VALVE - IN-VIVO EVALUATION OF TISSUE EXTRACTION, The Annals of thoracic surgery, 60(2), 1995, pp. 359-364
The major functional problem with bioprostheses is poor long-term dura
bility. Bioprosthetic valves fail because of calcification and mechani
cal fatigue, both of which result from the glutaraldehyde fixation pro
cess. In an effort to develop a biologically active, non-cross-linked
bioprosthetic valve, we devised a cellular extraction process. We test
ed the mechanical integrity of the processed valves and cultured both
human and porcine cells on this material. To test the potential for ca
lcification, we implanted strips of fresh, extracted, and glutaraldehy
de-treated porcine heart valve tissue subcutaneously into 3-week-old S
prague Dawley rats for 21 days. We used atomic absorption spectroscopy
to measure the extent of calcium accumulation and histopathologic ass
essment to evaluate the antigenic response. We found that the cell ext
raction process significantly reduced the propensity of the material t
o calcify in vivo (mean +/- standard deviation, 4.12 +/- 1.02 mg/g cal
cium extracted versus 10.75 +/- 3.9 mg/g calcium fresh versus 79.6 +/-
18.3 mg/g calcium glutaraldehyde fixed) but increased the antigenicit
y, as evidenced by increased cellular activity and resorption. Althoug
h they may reduce calcification, conventional detergent-based cell ext
raction techniques do not completely remove porcine aortic valve antig
ens and may in fact increase the antigenicity of the valve cusp materi
al.