OBJECTIVES: Bioprosthetic aortic valves degenerate over time, and differences between brands could be expected. We compared two brands implanted in three different centers serving 3.3 million people.
METHODS: Between 2000-2014 we identified 1,241 bioprosthetic aortic valve replacements using Mitroflow (Sorin, Milan, Italy) and 3,212 using Perimount (Edwards Lifesciences, Irvine, CA, USA) covering 88% of all aortic valve replacements in the region. Average differences in t-year mortality were derived from Cox regression.
RESULTS: The complete case analyses included 881 Mitroflow replacements and 2,488 Perimount replacements. The median follow-up time and 25/75 percentiles was 5.0 years (3.3-7.2) and 8.4 (5.1-10.6) years for Perimount and Mitroflow respectively. Multiple Cox regression analyses demonstrated significantly higher mortality with Mitroflow valves compared with Perimount (hazard ratio 1.27; 95% CI: 1.1-1.5; p<0.001). Average risk of death within five years was 25.0% with Mitroflow and 20.4% with Perimount. Average difference in 5-year mortality based on Cox regression was 4.60% in favor of Perimount (95% CI: 1.02-8.02%; p=0.01) and the number needed to harm was 21.9 (95% CI: 12.7-80.5) within five years. Propensity matching confirmed two year survival differences 4.6% in favor of Perimount (95% CI: 1.2-7.9%; p=0.004), and further confirmed in a series of subgroups and a double robust analysis that takes into account both propensity for treatment and covariate relation to outcome.
CONCLUSIONS: Mitroflow valves were associated with a significantly increased risk of death when compared to Perimount valves.