Stroke: clinical factors and provider volume of carotid endarterectomy may influence the risk of dying.

Clinical bottom line (level 2b)

  1. About 1% of patients undergoing carotid endarterectomy died before hospital discharge.
  2. Patients undergoing carotid endarterectomy may be at an increased risk of dying in-hospital if they had nonelective admission, congestive heart failure, atrial fibrillation, mitral or aortic valve disorder or were of increasing age.
  3. Patients undergoing carotid endarterectomy may be at an increased risk of dying in-hospital if they had a surgeon who performed less than 5 such operations annually in a hospital that performed 100 or less operations annually.
Hannan et al: Stroke 1998; 29: 2292-2297
Expires May 2003

The study

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

Setting: population-based, USA

28207 patients (aged mean 70 years, 57% male) undergone carotid endarterectomy between 1990 and 1995

Factors studied:
  • mortality
  • age increase of 1 year
  • nonelective admission
  • congestive heart failure
  • atrial fibrillation
  • mitral valve disorder
  • aortic valve disorder




    • Multivariate analysis was used to adjust for confounding factors.

    100% followed for until hospital discharge
    Outcomes studied:
  • mortality

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    mortality until hospital discharge 336/28207 1.19%
    (1.07% to 1.32%)

    prognostic factor for
    mortality     		time to outcome control rate (%) adjusted OR
    (95% CI)
    age increase of 1 year ? 1.03
    ( to )
    nonelective admission ? 2.43
    ( to )
    congestive heart failure ? 4.16
    ( to )
    atrial fibrillation ? 2.02
    ( to )
    mitral valve disorder ? 1.81
    ( to )
    aortic valve disorder ? 2.61
    ( to )

    • Risk-adjusted in-hospital mortality for patients having surgeons with annual carotid endarterectomy volumes of <5 in hospitals with annual carotid endarterectomy volumes of = 100 was 1.96% (95% CI 1.47 to 2.57).
    • Risk-adjusted in-hospital mortality for patients having surgeons with annual volumes of = 5 in hospitals with annual carotid endarterectomy volumes of >100 was 0.94% (95% CI 0.73 to 1.19).

    Comments

    1. Not enough data was given to calculate NNF+s, and no confidence intervals were given for the odds ratios, so it is unclear as to whether or not they are significant.

    Citation

    1. Hannan EL, Popp AJ, Tranmer B, et al: Relationship between provider volume and mortality for carotid endarterectomy in New York State. Stroke 1998; 29: 2292-2297
    Contributor: Clare Wotton and Musab Hayatli, December 1999
    Reviewer:

    Clinical Question.
    Patient carotid endarterectomy
    Intervention or Exposure presence of prognostic factors
    Comparison absence of prognostic factors
    Outcome in-hospital mortality