Choice of prosthetic heart valve in today's practice.

In this update, current guidelines addressing prosthesis selection published by the American College of Cardiology/American Heart Association (ACC/AHA) and the European Society of Cardiology (ESC) are discussed, along with additional data that affect choices in valve prostheses. The case of a 50-year-old man undergoing aortic valve replacement is used to address anticipated operative mortality, risk of reoperation, and valverelated morbidity and mortality. The apparent advantages associated with the use of a bioprosthesis even in a relatively young patient help to explain current clinical trends toward the increasing use of tissue valves. We also provide a simplified algorithm that may be used to facilitate the choice of valve procedure in patients with heart valve disease. The outcomes after surgery for valvular heart disease in terms of survival, functional status, and quality of life are determined primarily by patientrelated factors such as age, ventricular function, and other comorbidities.1 However, outcomes also are influenced by surgical factors; the best clinical outcomes often are associated with valve repair, although mitral repair is not always possible and aortic valve repair in adults remains the exception rather than the rule. For patients who require valve replacement, the valve prosthesis can significantly influence outcome. The ideal prosthetic valve that combines excellent hemodynamic performance and long-term durability without increased thromboembolic risk or the need for long-term anticoagulation does not exist. Hence, patients and their physicians need to choose between a mechanical and a tissue (bioprosthetic) valve. In general, the advantageous durability of mechanical valves is offset by the risk of thromboembolism and the need for longterm anticoagulation and its associated risk of bleeding. In contrast, bioprosthetic valves do not require long-term anticoagulation yet carry the risk of structural failure and reoperation.2,3 Two historic randomized clinical trials compared outcomes after valve replacement with a first-generation porcine heterograft and the original Bjork-Shiley tilting-disc mechanical valve: the Edinburgh Heart Valve Trial, conducted between 1975 and 1979 with an average follow-up of 12 years,4 and the Veteran Affairs (VA) Cooperative Study on Valvular Heart Disease, conducted between 1979 and 1982 with an average follow-up of 15 years.5 The Edinburgh trial4 alone showed a small survival advantage associated with a mechanical valve in the aortic but not in the mitral position; both trials showed increased bleeding associated with mechanical valves and increased reoperation with tissue valves; and both showed that structural failure of tissue valves and overall thromboembolic complications were greater after mitral than after aortic valve replacement. Although these trials are notable for their prospective, randomized design, their major limitation is that comparisons were made between first-generation porcine heterografts and the Bjork-Shiley mechanical valve, all of which are now obsolete. Thus, the ability to extrapolate these data to decisions made in modern practice is limited. To a large degree, based on these historical studies and in the interest of freedom from reoperation, previous guidelines from the ACC/AHA heavily weighted patient age in decisions between using a tissue and mechanical prosthesis.6 Without robust, large-scale, multicenter, randomized trials comparing current-generation tissue and mechanical valves, the revised 2006 ACC/AHA guidelines7 and