Methods for treating implantable biological tissues to mitigate the calcification thereof and bioprosthetic articles treated by such methods

DETAILED DESCRIPTION The present invention specifically addresses and alleviates the above-mentioned deficiencies associated with the prior art.
More particularly, the present invention comprises a method for treating glutaraldehyde fixed biological tissue or biological tissue fixed with other chemicals so as to inhibit later calcification of the tissue following implantation of the tissue into a mammalian body.
The method comprises placing the biological tissue in contact with glutaraldehyde or another chemical fixative and then heating the glutaraldehyde or other fixative and/or causing the glutaraldehyde or other fixative to be polymerized by thermal, chemical or mechanical means.
In the preferred embodiment of the present invention the biological tissue is disposed within a container containing a 0.
625% solution of glutaraldehyde comprising approximately 26 ml/l glutaraldehyde (25%); approximately 4.
863 g/l HEPES buffer; approximately 2.
65 g/l MgCl.
sub.
2 .
6H.
sub.
2 O; and approximately 4.
71 g/l NaCl.
The balance of the solution comprises double filtered H.
sub.
2 O.
Sufficient NaOH is added to adjust the pH to approximately 7.
4.
The glutaraldehyde solution is heated to between approximately 35-55.
degree.
C.
for approximately 4-22 weeks.
The biological tissue may be heat treated any time prior to implantation thereof within a mammalian body.
For example, the tissue may be treated before fixing thereof.
Treatment before fixing of the biological tissue merely involves heating it in a saline solution (9 g/l NaCl) or any other physiologic solution at 25-80.
degree.
C.
for a few seconds to 22 weeks.
Alternatively, the tissue may be treated during fixing thereof, while the tissue is disposed within a glutaraldehyde solution.
Treatment during fixing of the biological tissue merely involves heating of the glutaraldehyde solution to approximately 25-80.
degree.
C.
for approximately a few seconds to several months.
The preferred range is 35 to 55.
degree.
C.
for 4-22 weeks.
Alternatively, the biological tissue is treated after fixing thereof, and before storage thereof