Stroke: site of infarction may affect risk of recurrent stroke.

Clinical bottom line (level 4)

  1. A fifth of patients who have a first ever cerebral infarction were dead at 1 year.
  2. A seventh of patients who had a first ever cerebral infarction will had a recurrent stroke by 1 year.
  3. Patients who had a first ever cerebral infarction may be at increased risk of a recurrent stroke by 1 year if they had a posterior circulation infarct.
  4. Patients may be at a decreased risk of a recurrent stroke by 1 year if they had a lacunar infarct.
Bamford et al: Lancet 1991; 337: 1521-1526
Expires November 2002

The study

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

Setting: community-based, UK

543 patients (aged mean 73 years, 50% male) cerebral infarction with first ever stroke- diagnosed by CT scan or necropsy examination

Excluded if
  • unknown clinical syndrome



    • Factors studied:
  • death, recurrent stroke
  • lacunar infarct
  • posterior circulation infarct




    • 100% followed for 12 months
    Outcomes studied:
  • death
  • death with lacunar infarcts
  • death with total anterior circulation infarct
  • death with partial anterior circulation infarct
  • death with posterior circulation infarct
  • recurrent stroke fatal or non-fatal

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    death 12 months 124/543 22.8%
    (19.3% to 26.4%)
    death with lacunar infarcts 12 months 15/543 2.76%
    (1.38% to 4.14%)
    death with total anterior circulation infarct 12 months 55/543 10.1%
    (7.59% to 12.7%)
    death with partial anterior circulation infarct 12 months 30/543 5.52%
    (3.60% to 7.45%)
    death with posterior circulation infarct 12 months 24/543 4.42%
    (2.69% to 6.15%)
    recurrent stroke 12 months 76/543 14.0%
    (11.1% to 16.9%)

    prognostic factor for
    recurrent stroke     		time to outcome control rate (%) unadjusted OR
    (95% CI)    		 NNF+
    (95% CI)
    lacunar infarct 12 months 76/543
    (14%)     		0.50
    (0.30 to 0.80)     		-15
    (-40 to -11)
    posterior circulation infarct 12 months 76/543
    (14%)     		1.80
    (1.00 to 3.10)     		12
    (5 to -)

    Comments

    1. It is not stated whether a multivariate analysis was performed on the prognostic factors, so they have been taken as not being adjusted for confounding factors.
    2. There was a trend towards increased risk of recurrent stroke in patients with partial anterior circulation infarct (hazard ratio 1.3; 95% CI: 0.8 to 2.3).

    Citation

    1. Bamford J, Sandercock P, Dennis M, et al: Classification and natural history of clinically identifiable subtypes of cerebral infarction. Lancet 1991; 337: 1521-1526
    Search Terms: stroke in Best Evidence
    Contributor: Nick Shenker and Clare Wotton, November 1999
    Reviewer: Graeme Hankey

    Clinical Question.
    Patient first ever stroke
    Intervention or Exposure infarct type
    Comparison
    Outcome mortality