Mechanical versus bioprosthetic mitral valve replacement in patients <65 years old

Objective: Because of its durability, the mechanical valve is typically chosen for young patients undergoing mitral valve replacement (MVR). However, a bioprosthetic valve might have the benefit of valve-in-valve transcatheter valve replacement when valve failure occurs. We examined the outcomes in patients who had undergone mechanical valve MVR (MVRm) versus bioprosthetic valve MVR (MVRb) in patients aged <65 years. Methods: A total of 768 consecutive patients aged <65 years, who had undergone MVR from January 1991 to June 2012 were identified. Propensity matching was used to derive a case-control subset for analysis. Long-term outcomes were collected by chart review, routine patient follow-up, and query of the Social Security Death Index. The postoperative and long-term outcomes of interest included combined stroke and embolic events, reoperations, and mortality. Results: Of 768 consecutive patients, 627 were in the MVRm and 141 in the MVRb group. Propensity score matching yielded a cohort of 125 MVRb (89%) and 125 control MVRm patients with similar etiology mixes. The groups were similar in age (MVRm, 53.2 +/- 9.0 years; MVRb, 53.8 +/- 10.6 years; P = .617) and other preoperative characteristics. The postoperative outcomes were also similar between the 2 groups, including reoperation for bleeding, stroke, deep sternal infection, sepsis, and length of hospital stay. The operative mortality was also similar (MVRm, 5.6%; MVRb, 8.0%; P = .617). However, Kaplan-Meier analysis showed the MVRb group had a greater reoperation rate (P = .001) and shorter estimated survival (11.3 vs 13.5 years, P = .004). The incidence of bleeding and stroke or embolic events between the 2 groups was similar. Conclusions: In the present report, MVRb for patients <65 years old was associated with a high reoperation rate and decreased survival. Although a future transcatheter valve-in-valve technique for a failed bioprosthetic valve might reduce the risk of reoperation, this finding confirms the safety of mechanical valves in this group.