Does the type of biological valve affect patient outcome?

Patient background mortality and excess mortality related to aortic valve disease may play a greater role than implanted valve type in explaining the observed survival differences after aortic valve replacement. This study attempts to identify the differences between the performance of selected biological valves, given similar patient characteristics and excess mortality. Four biological valve types, the Carpentier-Edwards pericardial and supra-annular valve, Medtronic Freestyle valve and allografts were used for this analysis. Primary data calculated observed patient-survival and median time to structural valvular deterioration. We then used a microsimulation model to calculate age-specific patient survival and reoperation- and event-free life expectancies. The model incorporated the US population mortality and a uniform excess mortality, while the hazards of valve-related events after implantation of the four valve types were estimated from corresponding meta-analysis and primary data. Observed 10-year survival (60-69)-year age group survival and median time to SVD for the different valve types did not differ. Microsimulation calculated, for a 65-year-old male for example, a 10-year survival of 51%, 51%, 53% and 56% for Carpentier-Edwards pericardial and Supra-annular valve, Freestyle and allografts, respectively. Patient life expectancy was 10.8, 10.8, 11.0 and 11.4 years, respectively. Assuming uniform patient characteristics and excess mortality, the observed difference in performance between the four biological valve types is less marked. Patient selection and the timing of operation may explain most of the observed differences in prognosis after aortic valve replacement with biological prostheses.