Infective endocarditis: valve replacement: preoperative factors increased the risk.

Clinical bottom line (level 1b)

  1. Around 6% of patients who had recent replacement of one or more cardiac valves were likely to have prosthetic valve endocarditis within 7 years.
  2. Patients with heart valve replacement were more likely to have endocarditis if they had:
    • preoperative hypoxia (NNF = 11 for 7 years)
    • preoperative active endocarditis (NNF = 19 for 7 years)
    • superficial wound infection (NNF = 9 for 7 years)
    • resident as primary surgeon (NNF = 34 for 7 years)
    • preoperative valve lesions (p=0.020)
  3. Nearly half of patients with prosthetic valve endocarditis died.
Grover et al: Journal of Thoracic Cardiovascular Surgery 1994; 108: 207-214
Expires October 2003

The study

Prospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: thirteen Veterans' Affairs medical centres

1137 patients (aged mean 60 years, 100% male) underwent replacement of one or more cardiac valves with or without concomitant cardiac procedures (735 patients with aortic valve replacement; 274 with mitral valve, 94 with multiple valve; 34 missing data)

Factors studied:
  • preoperative hypoxia
  • active endocarditis
  • superficial wound infection
  • resident as primary surgeon




    • Cox's regression analysis was used to adjust for confounding factors.

    100% followed for mean 7.7 years
    Outcomes studied:
  • prosthetic valve endocarditis 1. fever and two or more positive blood cultures for the same organism with no other obvious infection; 2. bacteria cultured in pus or vegetation near prosthetic valve; 3. bacteria cultured in septic emboli
  • death from prosthetic valve endocarditis

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    prosthetic valve endocarditis mean 7.7 years 66/1137 5.80%
    (4.45% to 7.16%)
    death from prosthetic valve endocarditis mean 7.7 years 30/66 45.6%
    (33.4% to 57.5%)

    prognostic factor for
    prosthetic valve endocarditis     		time to outcome adjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    preoperative hypoxia mean 7.7 years 7.9
    ( to )     		11
    ( to )
    active endocarditis mean 7.7 years 6.8
    ( to )     		19
    ( to )
    superficial wound infection mean 7.7 years 3.5
    ( to )     		9
    ( to )
    resident as primary surgeon mean 7.7 years 3.2
    ( to )     		34
    ( to )

    • p-values for each relative risk:
      • hypoxia p=0.001
      • preoperative endocarditis p=0.003
      • resident as primary surgeon p=0.050
      • superficial wound infection p=0.0037
    • Preoperative valve lesions were also predictors of prosthetic valve endocarditis, but no relative risk was given (p=0.020)
    • Valve position (aortic versus mitral) was of borderline statistical significance, p=0.0809.

    Citation

    1. Grover FL, Cohen DJ, Oprian C, et al: determinants of the occurrence of and survival from prosthetic valve endocarditis: experience of the Veterans Affairs cooperative study on valvular heart disease. Journal of Thoracic Cardiovascular Surgery 1994; 108: 207-214
    Contributor: Clare Wotton and Musab Hayatli, October 2000
    Reviewer:

    Clinical Question.
    Patient prosthetic valve
    Intervention or Exposure risk factor
    Outcome infective endocarditis