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Original research
Endocarditis risk with bioprosthetic and mechanical valves: systematic review and meta-analysis
  1. Mahesh Anantha-Narayanan1,
  2. Yogesh N V Reddy2,
  3. Varun Sundaram3,4,
  4. Mohammad Hassan Murad5,
  5. Patricia J Erwin2,
  6. Larry M Baddour6,
  7. Hartzell V Schaff7,
  8. Rick A Nishimura2
  1. 1 Section of Cardiovascular Diseases, Yale-New Haven Hospital, New Haven, Connecticut, USA
  2. 2 Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
  3. 3 Harrington Heart and Vascular Institute, University Hospitals Case Medical Center, Cleveland, Ohio, USA
  4. 4 Division of Population Science, National Heart and Lung Institute, London, UK
  5. 5 Knowledge and Evaluation Research, Mayo Clinic, Rochester, Minnesota, USA
  6. 6 Division of Infectious Diseases, Mayo Clinic Department of Health Sciences Research, Rochester, Minnesota, USA
  7. 7 Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota, USA
  1. Correspondence to Dr Mahesh Anantha-Narayanan, Section of Cardiovascular Diseases, Yale-New Haven Hospital, New Haven, CT 06510, USA; manantha{at}


Objective Bioprosthetic valves are being used with increased frequency for valve replacement, with controversy regarding risk:benefit ratio compared with mechanical valves in younger patients. However, prior studies have been too small to provide comparative estimates of less common but serious adverse events such as infective endocarditis. We aimed to compare the incidence of infective endocarditis between bioprosthetic valves and mechanical valves.

Methods We searched PubMed, Cochrane, EMBASE, Scopus and Web of Science from inception to April 2018 for studies comparing left-sided aortic and mitral bioprosthetic to mechanical valves for randomised trials or observational studies with propensity matching. We used random-effects model for our meta-analysis. Our primary outcome of interest was the rate of infective endocarditis at follow-up.

Results 13 comparison groups with 43 941 patients were included. Mean age was 59±7 years with a mean follow-up of 10.4±5.0 years. Patients with bioprosthetic valves had a higher risk of infective endocarditis compared with patients receiving mechanical valves (OR 1.59, 95% CI 1.35 to 1.88, p<0.001) with an absolute risk reduction of 9 per 1000 (95% CI 6 to 14). Heterogeneity within the included studies was low (I2=0%). Exclusion of the study with maximum weight did not change the results of the analysis (OR 1.57, 95% CI 1.14 to 2.17, p=0.006). A meta-regression of follow-up time on incidence of infective endocarditis was not statistically significant (p=0.788) indicating difference in follow-up times did not alter the pooled risk of infective endocarditis.

Conclusions Bioprosthetic valves may be associated with a higher risk of infective endocarditis. These data should help guide the discussion when deciding between bioprosthetic and mechanical valves in individual patients.

  • valve disease surgery
  • valvular heart disease
  • endocarditis
  • meta-analysis
  • systemic review

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  • MA-N and YNVR contributed equally.

  • Correction notice Since the online publication of this article, the author name 'Larry M Baddour' was updated to include the middle initial.

  • Contributors Conception or design of the work: MAN, YNVR, VS. Data collection: MAN, YNVR, VS, PJE. Data analysis and interpretation: MAN, YNVR, VS, MHMM. Drafting the article: all authors. Critical revision of the article: LB, HVS, RAN. Final approval of the version to be published: all authors.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data sharing not applicable as no datasets generated and/or analysed for this study.

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