title: Invited commentary.
authors.affiliation: Department of Cardiothoracic Surgery, University of Vienna, Waehringer Guertel 18-20, Wien A1090, Austria. marie-theres.kasimir@meduniwien.ac.at
authors.forename: Marie-Theres
authors.initials: MT
authors.lastname: Kasimir
authors.forename: Ernst
authors.initials: E
authors.lastname: Wolner
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D007421:Intestine, Small; D011664:Pulmonary Valve; D012756:Sheep