The burden of valvular heart disease leads to over 300,000 heart valve replacements each year worldwide.1 This number will probably triple by 2050, and valvular heart disease will likely be considered as the future next cardiac epidemic.2 Despite tireless efforts and perseverance from engineers and cardiovascular specialists, valve replacement still lacks an ideal therapy. In the 1950s, Dwight Harken coined the "Ten Commandments" for the perfect prosthetic heart valve.3 The optimal heart valve prosthesis would have endless durability, absence of thrombogenicity to avoid anticoagulation, and no inherent postoperative gradient. However, almost 70 years later, there is still no perfect valve substitute4: those patients who undergo heart valve replacement exchange valvular heart disease for prosthetic heart valve disease.5 The most influential factors affecting prosthesis selection include the individual surgical risk, the estimated life expectancy, barriers to lifelong anticoagulation, and the patient’s personal preference. The latter must be based on an informed understanding of the trade-offs between the incremental risk of thromboembolic and hemorrhagic complications associated with mechanical valve replacement and lifelong anticoagulation, versus the risk of reoperation for structural valve degeneration associated with bioprosthetic valve replacement.5,6 Management of patients with prosthetic heart valves consists of surveillance and prophylaxis, both focused on prevention and diagnosis of the major complications associated with prosthetic heart valves. Patient outcomes continue to improve after valve replacement thanks to clinical and technical developments: in the field of surgical valve replacement, these developments have been characterized in recent years by steady incremental progress, contrasting sharply with the rapid technological evolution7 and uptake of transcatheter valve replacement, a difference that will likely define this field.8,9
TYPES OF PROSTHETIC VALVES
There are two main categories of prosthetic valve: mechanical and biological (bioprostheses) (Fig. 52–1). The profusion of models in each of these categories in contemporary use is largely the result of failure to produce any single prosthesis with an optimal risk profile, despite seven decades of effort. The proportion of bioprosthetic valves implanted in all age groups has increased steadily over the last decade,10 most markedly in patients between 55 and 64 years, and today mechanical valves are generally implanted in a minority of patients.9 In addition, high volume (> 250 cases per year) and academic centers are more likely to use biological valves (Fig. 52–2).
Currently available surgical prosthetic heart valves from the major manufacturers. Courtesy of Medtronic, Inc., Minneapolis, MN; St. Jude Medical, Inc., Minneapolis, MN; Sorin Group, Inc., Milan, Italy; On-X Life Technologies, Inc., Austin, TX; Edwards Lifesciences, Ltd., Irvine, CA.
Estimated national volume of bioprosthetic and mechanical aortic valve replacement procedures, by year, from 1998 to 2011(left). Percentage of aortic valve replacements in which bioprosthetic valves were implanted, over time, ...