Long-term outcomes with mechanical and tissue valves.

Recent publications comparing outcomes in patients receiving tissue or tissue heart valve prostheses have provided important information to guide valve selection. The major outcome events studied include thromboembolism, hemorrhage, and overall survival. Both small randomized and larger retrospective studies of outcomes after heart valve replacement have demonstrated similar rates of thromboembolism with tissue and mechanical valves. Hemorrhage rates have been consistently higher in aortic mechanical valves. However, patients receiving mitral tissue valves have had similar rates of hemorrhage as those receiving mechanical mitral valves in one randomized trial and one large retrospective study suggesting that hemorrhage rates are not higher for mechanical mitral valves. In contrast, the published randomized and observational studies consistently demonstrate much higher valve failure rates in tissue valve recipients, regardless of valve position. Overall survival in the longest randomized study was better for aortic valve patients receiving a mechanical valve compared to those receiving a tissue valve. No survival differences have been observed in mitral valve patients. Analysis of age related differences in outcomes suggests that aortic valve patients under age 65 and mitral valve patients under age 70 should receive mechanical valves. These findings are consistent with current ACC/AHA guidelines.