INHIBITION OF THE CALCIFICATION OF PORCINE VALVE TISSUE BY SELECTIVE LIPID REMOVAL

Since the development of cardiac prostheses, numerous chemical treatme nts have been assayed to prevent the process of their mineralization, causing 60% of the failures. The effect of the extraction of lipids fr om the tissue employed in porcine valves is assessed in a model of sub cutaneous implantation in rats. Tissue from aortic and pulmonary porci ne valves was treated with chloroform-methanol and 0.625% glutaraldehy de and was implanted into young rats for periods of 21 and 60 d. The c alcium accumulated was then quantified by atomic absorption. The effec tiveness of this treatment is demonstrated by the detection of much lo wer calcium values than in the control group. For aortic valve tissue, the values obtained were 40.5 and 188.1 mu gCa(2+)/mg dry weight of t issue for implantation times of 21 and 60 d, respectively, versus 5.48 and 1.4 mu gCa(2+)/mg dry weight of tissue for the same tissue treate d with chloroform-methanol, ihe values obtained with pulmonary valve t issue were very similar: 72.46 and 108.06 mu gCa(2+)/mg dry weight tis sue versus 0.67 and 0.80 mu Ca2+/mg dry weight tissue for implantation periods of 21 and 60 d, respectively. Thus, phospholipids may be tota lly or partially responsible for the calcification of the porcine valv e tissue employed in the construction of cardiac bioprostheses.