Despite distinct advantages over mechanical cardiac valve prostheses, the use of bioprosthetic valves remains limited, due to poor long-term durability, primarily as a result of tissue calcification. A novel in vitro, anticalcification process based on treatment of porcine and human heart valves with metallocene dichlorides, as well as with amino acids (phenylalanine, aspartic acid, glutamic acid), has been developed. This anticalcification process reduced mineralization of porcine and human valves up to 32% and 28%, respectively.