Infective endocarditis: vegetations on echocardiography did not predict embolic events.

Clinical bottom line (level 2b)

  1. Over a third of patients with left-sided native valve infective endocarditis had vegetations.
  2. Around a seventh had embolic events.
  3. The presence of vegetations on echocardiography was not predictive of future embolic events.
  4. The rate of embolic events decreased over time following the initiation of antimicrobial treatment.
Steckelberg et al: Annals of Internal Medicine 1991; 114: 635-640
Expires July 2003

The study

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

Setting: university hospital, USA, 1978 to 1987

207 patients (aged range 9 to 96 years; median 60, ?% male) active, left-sided, native valve infection, who had a 2-dimensional echocardiographic examination within 72 hours of starting antimicrobial treatment. Diagnosed with infective endocarditis if any of:
  • histopathologic evidence of infective endocarditis
  • multiple positive blood cultures in the absence of another known primary source of bacteraemia together with at least two of: fever, new or changing murmur, newly developed splenomegaly, hypersensitivity or microvascular phenomenon (ie. Janeway lesions, Osler's nodes or Roth spots)
  • intermittently positive blood cultures, or negative blood cultures when cultures were first obtained only after empiric antimicrobial therapy, with at least three signs or symptoms of infective endocarditis


Excluded if
  • echocardiography was done >72 hours from the time at which antibiotic therapy began




    • Cox proportional hazards analysis used to adjust for confounding factors

    100% followed for during 'period of risk'
    Outcomes studied:
  • emboli events
  • vegetation present
  • vegetation indeterminate
  • vegetation absent

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    emboli events during 'period of risk' 27/207 13%
    (8.5% to 18%)
    vegetation present during 'period of risk' 79/207 38%
    (32% to 45%)
    vegetation indeterminate during 'period of risk' 46/207 22%
    (17% to 28%)
    vegetation absent during 'period of risk' 82/207 40%
    (33% to 46%)

    prognostic factor for
    emboli events     		time to outcome unadjusted RR
    (95% CI)
    no vegetation during 'period of risk' 1.4
    (0.6 to 3.3)

    • rate of first embolic event (p<0.001):
      • first week: 13 per 1000 patient days
      • second week: <1.2 per 1000 patient days
    • Cardiac arrhythmia, type of organism, history of embolus and the valve involved also did not predict risk of embolism.

    Comments

    1. The end point in the study was the first embolic event during antimicrobial therapy and therefore does not include multiple embolic events occurring in individual patients.

    Citation

    1. Steckelberg JM, et al: Emboli in infective endocarditis: the prognostic value of echocardiography. Annals of Internal Medicine 1991; 114: 635-640
    Search Terms: endocarditis and echocardiography in Best Evidence
    Contributor: Carl Heneghan, Sumit Dhingra and Chris Ball, February 1999
    Reviewer:

    Clinical Question.
    Patient infective endocarditis
    Intervention or Exposure vegetations on ECHO
    Outcome embolic events, prognosis