Background: Mechanical valves and bioprostheses are widely used for aortic val ve replacement. Though previous randomised studies indicate that there is no imp ortant difference in outcome after implantation with either type of valve, knowl edge of outcomes after aortic valve replacement is incomplete. Objective: To pre dict age and sex specific outcomes of patients after aortic valve replacement wi th bileaflet mechanical valves and stented porcine bioprostheses, and to provide evidence based support for the choice of prosthesis. Methods: Meta analysis of published results of primary aortic valve replacement with bileaflet mechanical prostheses(nine reports, 4274 patients, and 25 726 patient years) and stented porcine bioprostheses (13 reports, 9007 patients, and 54 151 patient years) was used to estimate the annual risks of postoperative valve related events and th eir outcomes. These estimates were entered into a microsimulation model, which w as employed to calculate age and sex specific outcomes after aortic valve replac ement. Results: Life expectancy(LE) and event free life expectancy(EFLE) for a 65 year old man after implantation with a mechanical valve or a bioprosthesis we re 10.4 and 10.7 years and 7.7 and 8.4 years, respectively. The lifetime risk of at least one valve related event for a mechanical valve was 48%, and for a bio prosthesis, 44%. For LE and EFLE, the age crossover point between the two valve types was 59 and 60 years, respectively. Conclusions: Meta analysis based micr osimulation provides insight into the long term outcome after aortic valve repla cement and suggests that the currently recommended age threshold for implanting a bioprosthesis could be lowered further.
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