Conclusion
Biological prosthesis valve dysfunction is a clinically significant process. It has become a major issue and a hot topic considering the growing rate of bioprosthesis implantation and improved long-term patient survival.
Although biological prosthesis has important advantages over mechanical, durability is the major limitation of their implantation. The design and development of new biological bioprosthesis must reproduce the structure, and, more important, the biology of native heart valves. Understanding the complex biologically functional and dynamic system of the heart valves will elucidate how bioprosthesis can match their natural behavior. Every surgeon should be aware of their biological complexity to understand and discuss new tissue valve technologies, to provide patients heart valves with improved durability and better performance.
Although biological heart valves have been used for more than 50 years, bioprosthesis dysfunction remains a challenging and intriguing field, with an enormous quantity of work and research ahead in each of its subjects. SVD remains an intriguing field because the pathophysiology of SVD is not yet completely known. Only in the past few years, studies have unveiled new biological pathways. And that is the reason why basic research on the pathophysiology of SVD remains crucial. We will only achieve new and efficient tissue development if we deepen our knowledge of the biological processes of native heart valves. Fortunately, research on tissue heart valves is now wide and covers several different fields, such as 1) the effects of Glut-fixation, 2) non-Glut fixation, 3) mechanisms of calcification and non-calcification dysfunction, 4) anticalcification approaches, 5) biology of the valvular cells and 6) tissue-engineered valves (41).
Concluding, biological heart prosthesis dysfunction is a complex and multifactorial process, with biological, chemical, mechanical and immunological factors. Chemical changes caused by Glut, and consequent calcification, have been the main target of tissue valve development. However, as pathophysiology has been explored, with more detailed knowledge on cell structure and function and on the inflammation associated with bioprosthetic valve implantation, new questions arise. SVD remains a challenging field of research and novel interventions and developments need to focus on strategies that target the cell and immune events responsible for degeneration and rejection of the tissues. Moreover, new tissues must keep some of the biological proprieties of native heart valves, since valve changes in conformation during the cardiac cycle and regeneration processes are two essential but many times forgotten aspects of SVD.