title: Early mortality after aortic valve replacement with mechanical prosthetic vs bioprosthetic valves among Medicare beneficiaries: a population-based cohort study.
abstract: OBJECTIVE
  Early mortality for patients who undergo aortic valve replacement (AVR) may differ between mechanical and biological prosthetic (hereinafter referred to as bioprosthetic) valves. Clinical trials may have difficulty addressing this issue owing to limited sample sizes and low mortality rates.
  
  
  OBJECTIVE
  To compare early mortality after AVR between the recipients of mechanical and bioprosthetic aortic valves.
  
  
  METHODS
  A retrospective analysis of patients 65 years or older in the Medicare databases who underwent AVR from July 1, 2006, through December 31, 2011. In the mixed-effects models adjusting for physician and hospital random effects, we estimated odds ratios (OR) of early mortality to compare mechanical vs bioprosthetic valves.
  
  
  METHODS
  Mechanical or bioprostheticaortic valve replacement.
  
  
  METHODS
  Early mortality was measured as death on the date of surgery, death within 1 to 30 or 31 to 365 days after the date of surgery, death within 30 days after the date of hospital discharge, and operative mortality (death within 30 days after surgery or at discharge, whichever is longer).
  
  
  RESULTS
  Of the 66 453 Medicare beneficiaries who met inclusion criteria, 19 190 (28.88%) received a mechanical valve and 47 263 (71.12%) received a bioprosthetic valve. The risk for death on the date of surgery was 60% higher for recipients of mechanical valves than recipients of bioprosthetic valves (OR, 1.61 [95% CI, 1.27-2.04; P < .001]; risk ratio [RR], 1.60). The risk difference decreased to 16% during the 30 days after the date of surgery (OR, 1.18 [95% CI, 1.09-1.28; P < .001]; RR, 1.16). We found no differences within 31 to 365 days after the date of surgery and within the 30 days after discharge. The risk for operative mortality was 19% higher for recipients of mechanical compared with bioprosthetic valves (OR, 1.21 [95% CI, 1.13-1.30; P < .001]; RR, 1.19). The number needed to treat with mechanical valves to observe 1 additional death on the surgery date was 290; to observe 1 additional death within 30 days of surgery, 121. Consistent findings were observed in subgroup analyses of patients who underwent concurrent AVR and coronary artery bypass graft, but not in the subgroup undergoing isolated AVR.
  
  
  CONCLUSIONS
  In this cohort analysis of Medicare beneficiaries, use of mechanical aortic valves was associated with a higher risk for death on the date of surgery and within the 30 days after surgery compared with bioprosthetic aortic valves among patients who underwent concurrent AVR and coronary artery bypass graft but not isolated AVR.
authors.affiliation: Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Rockville, Maryland2currently with Office of Surveillance and Biometrics, Center for Devices and Radiological Health, US Food and Drug.
authors.forename: Dongyi Tony
authors.initials: DT
authors.lastname: Du
authors.affiliation: Acumen, LLC, Burlingame, California.
authors.forename: Stephen
authors.initials: S
authors.lastname: McKean
authors.affiliation: Centers for Medicare & Medicaid Services, Washington, DC.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kelman
authors.affiliation: Office of Device Evaluation, Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, Maryland.
authors.forename: John
authors.initials: J
authors.lastname: Laschinger
authors.affiliation: Acumen, LLC, Burlingame, California.
authors.forename: Chris
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Acumen, LLC, Burlingame, California.
authors.forename: Rob
authors.initials: R
authors.lastname: Warnock
authors.affiliation: Centers for Medicare & Medicaid Services, Washington, DC.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Worrall
authors.affiliation: Patient-Centered Comparative Effectiveness Program and MDEpiNet Science and Infrastructure Center, Weill Cornell Medical College, New York, New York.
authors.forename: Art
authors.initials: A
authors.lastname: Sedrakyan
authors.affiliation: Center for Delivery, Organization and Markets, Agency for Healthcare Research and Quality, Rockville, Maryland.
authors.forename: William
authors.initials: W
authors.lastname: Encinosa
authors.affiliation: Acumen, LLC, Burlingame, California8Department of Economics, Stanford University, Stanford, California.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: MaCurdy
authors.affiliation: Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Rockville, Maryland.
authors.forename: Hector S
authors.initials: HS
authors.lastname: Izurieta
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001705:Bioprosthesis / Q000706:statistics & numerical data*; D005260:Female; D006350:Heart Valve Prosthesis / Q000706:statistics & numerical data*; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality*; D006801:Humans; D008297:Male; D006278:Medicare; D012189:Retrospective Studies; D014481:United States