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Aortic Valve Replacement in Patients Aged 50 to 70 Years: Improved Outcome with Mechanical vs. Biological Prostheses
M. L. Brown, H. V. Schaff, C. J. Mullany, T. M. Sundt, J. A. Dearani, C. G. McGregor, T. A. Orszulak. Mayo Clinic, Rochester, MN
Background: Improved durability with bioprostheses have led some to recommend biological valves rather than mechanical prostheses for patients less than 65 years of age. We compared late results of contemporary bioprosthesis versus bileaflet mechanical prostheses in patients who underwent aortic valve replacement between 50 and 70 years of age.
Methods: In this retrospective study, patients received either a St. Jude bileaflet valve (MechV) or Carpentier-Edwards bioprosthesis (BPV). Operations were performed between January 1991 and December 2000, and the two groups were matched 1:1 according to age, gender, need for coronary artery bypass grafting (CABG), and valve size. Exclusion criteria included concomitant valvular procedures, aortic surgery, or arrhythmia procedures. The incidence of late complications and death were determined by survey follow-up and electronic medical records.
Results: Four hundred and forty patients were matched and follow-up was 92% complete with a median duration of 9.1 years in patients who received a MechV and 6.2 years in patients who received a BPV. The 5 year and 10 year unadjusted survivals were 87% (95% CI 83-92%) and 68% (CI 62-76%) for MechV and 72% (CI 66-78%) and 50% (CI 52-58%) for BPV respectively (p<0.01). Freedom from reoperation at 10 years was 98% (CI 94-99%) for MechV and 91% (CI 85-98%) for BPV (p=0.06). Rates of late stroke or other embolic events and incidence of endocarditis were similar between groups. Hemorrhagic complications requiring hospitalization occurred in 15% of patients with a MechV compared to 7% of patients with a BPV (p=0.01). Notably, 19% of patients with BPV were on warfarin at last follow-up. After adjusting for unmatched variables including diabetes, renal failure, lung disease, NYHA class, ejection fraction, and stroke, the use of a MechV was protective for late mortality (Hazard 0.47, p<0.01).
Conclusions: Patients aged 50 to 70 years who have aortic valve replacement with a MechV have a survival advantage compared to matched patients receiving a BPV. These findings question the current trend to recommend BPV for younger patients.
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