Biological or mechanical mitral valve replacement in patients 50–70 years of age—a propensity-adjusted analysis

OBJECTIVES: The choice of a bioprosthetic valve (BV) over a mechanical valve (MV) in middle-aged adults in the mitral position is still under debate. Each valve type has benefits and drawbacks. We examined the mid-term survival of patients aged 50-70 years after BV versus MV mitral valve replacement (MVR). METHODS: We conducted a multicentre, retrospective analysis of patients aged 50-70 years undergoing MVR from 2005 to December 2018 in 4 medical centres in Israel. To control for between-group differences, we used propensity-adjusted analysis. The primary end point was all-cause mortality. Secondary end points included reoperation, cerebrovascular accident and bleeding. RESULTS: During the study period, 2125 MVR procedures were performed. Of these, 796 were eligible for inclusion [539 (67.8%) MV replacement and 257 (32.2%) BV]. The mean age was 61.0 ± 5.4. There were 287 deaths during 4890 person-years of follow-up. The adjusted hazard ratio was (1.13 [0.85-1.49], P = 0.672). There was also no difference in the secondary end points. Subgroup analysis of patients aged 50-64 years showed a higher risk of mortality with BV (hazard ratio = 1.50 [1.07-2.1], P = 0.018). Reoperation was a strong predictor of mortality during the study period (72.2%). CONCLUSIONS: In patients aged 50-70 years, we found an interaction between age and MV or BV outcomes-those younger than 65 years gained a mortality advantage with MV, while outcomes were similar in the 65-70 age group. this supports the current guidelines recommending using MV in patients <65 years of age.