%0 Journal Article
%T Bioprosthetic Heart Valves: Impact of Implantation on Biomaterials
%A Pooja Singhal
%A Adriana Luk
%A Jagdish Butany
%J ISRN Biomaterials
%D 2013
%R 10.5402/2013/728791
%X Prosthetic heart valves are commonly used in the treatment of valvular heart disease. Mechanical valves are more durable than the bioprosthetic valves; however, the need for long-term anticoagulant therapy renders them unsuitable for some patient groups. In this paper we discuss the different types and models of bioprosthesis, and in particular, pericardial bioprosthesis. We also discuss the preimplantation preparation processes, as well as their postimplantation changes and modes of failure. 1. Introduction Prosthetic heart valves, used for the definitive treatment of diseased and dysfunctional native heart valves, have been in use since the mid 1960s. They are broadly divided into mechanical heart valves (MHVs) and bioprosthetic heart valves (BHVs). MHVs are made of synthetic material (e.g., polymers, metal, and carbon), where as BHVs are made of biologic tissues which are mounted on a fabric covered plastic frame, called a stent. MHVs are more durable, but their thrombogenicity and need for long-term anticoagulant therapy make them unsuitable for patients in some age groups especially older age groups. In contrast, BHVs are safe to implant, functionally similar to the native aortic valve, do not require long-term anticoagulant therapy, and are hence associated with reduced risk of hemorrhage. Since their introduction in the mid 1960s, BHVs have gone through many modifications, in their handling from time of harvesting to availability for implantation. Many tissues and different animal species aortic valves have been tried with varying results. Today, the most commonly used BHVs are those from porcine aortic valves and from calf pericardium. While the use of either one may be guided by patient age and other considerations, the trend in the United States and Europe has been towards greater use of tissue rather than mechanical valves [1]. This paper discusses bioprostheses, and in particular, pericardial bioprostheses. We also review the post-implantation changes in their biomaterial components and their modes of failure. 2. Classification of Bioprosthetic Valves Bioprosthetic replacement heart valves are derived from human (homograft) or animal (xenograft) tissues. 2.1. Homograft These are derived from cadaveric (human) aortic valves. They are cryopreserved and are implanted into the aortic root without a stent. Autograft. Patient¡¯s own valve was taken from one site (pulmonary) and implanted at another site, for example, pulmonary valve grafted into the aortic site. This predominately occurs in children with diseased native aortic valves [2]. 2.2.
%U http://www.hindawi.com/journals/isrn.biomaterials/2013/728791/