Prosthetic Valve Dysfunction

Approximately 85,000 valve substitutes are implanted in the United States and 275,000 worldwide each year, of which approximately half are mechanical valves and half are bioprosthetic valves. Despite the marked improvements in prosthetic valve design and surgical procedures over the past decades, valve replacement is not a panacea for the patient. Instead, native valve disease is traded for prosthetic valve disease and the outcome of patients undergoing valve replacement is indeed affected by prosthetic valve hemodynamics, durability, and thrombogenicity. Valve-related problems necessitate reoperation or cause death in approximately 50–60%of patients within 10 years after prosthetic valve implantation. This rate is similar for mechanical and bioprosthetic valves. However, the nature and time-related frequency of the specific valve-related complications vary with the type of prosthesis. Mechanical valves have a substantial risk of thromboemboli and thrombotic obstruction and they therefore require chronic anticoagulation therapy, which is in turn associated with an increased risk of hemorrhagic complications. Nonetheless, contemporary mechanical valves have an excellent durability. In contrast, bioprosthetic valves have a low risk of thromboembolism without anticoagulation. However, their durability is limited by calcific or non-calcific tissue deterioration. The purpose of this chapter is to provide an overview of the evaluation, mechanisms, prevention, and treatment of prosthetic valve dysfunction (Table 1).