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Observational study
Risk of vascular events is lower than expected in patients with transient ischaemic attack or minor stroke treated promptly by stroke specialists
  1. Christian H Nolte
  1. Correspondence to : Dr Christian H Nolte, Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin 12203, Germany; christian.nolte{at}charite.de

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Context

Previous studies estimated the risk of subsequent vascular events in patients with transient ischaemic attack (TIA) or minor stroke at 10–20% within 3 months.1 ,2 Prevention strategies have been adjusted since. Up-to-date numbers would help to detect a possible temporal trend in risk and to prospectively evaluate risk-scoring tools and specific risk factors in current patient populations. The TIA registry was set up to reassess aetiology, prognosis and risk stratification in the context of modern stroke prevention and management.

Methods

Patients included in this prospective registry had had a TIA or minor stroke within the past 7 days. Minor stroke was defined as 0 or 1 point on the modified Rankin Scale (mRS; 0 points indicate ‘no remaining symptoms at all’ and 1 point indicates that the patient has symptoms but can do all usual previous activities). Recruitment was restricted to dedicated institutions providing emergency evaluation including a stroke specialist and serving at least 100 patients per year with TIA/minor stroke. The registry assessed the prognostic value of the ABCD2 score, aetiology and findings on brain imaging. The ABCD2 score ranges from 0 (lowest risk) to 7 (highest risk) and is calculated on the basis of age, blood pressure, clinical presentation, duration of symptoms and presence of diabetes. The outcome was the composite end point of stroke, acute coronary syndrome (including myocardial infarction) and cardiovascular deaths at 1 year as assessed by stroke specialists.

Findings

One-year event rates were assessed in 4583 patients from 21 countries (age: 66.1±13.2 years, 60.2% male) between 2009 and 2011. The risk for the composite vascular outcome was 6.2% (95% CI 5.5 to 7.0%). The most common event was stroke (N=224, 5.1%). Within 3 months, 168 patients (3.7%) had suffered a stroke. It was also found that prediction of subsequent events was improved by considering large artery stenosis and brain imaging in addition to the established ABCD2 score. Of note, 22% of strokes occurred in patients with an ABCD2 score ≤4. This cut-off had been suggested to indicate less urgent evaluation according to the American Heart Association (AHA) guidelines previously.3

Commentary

This study did not compare patients with emergency evaluation by stroke specialists to those without. Nor was it the first to suggest that risk of stroke after TIA/minor stroke decreases through concerted efforts. The EXPRESS study had shown earlier that prompt initiation of evidence-based treatments after TIA/minor stroke is followed by a dramatic reduction in the risk of early recurrent stroke.1 However, the reported risk of stroke in this registry at 3 months (3.7%) is substantially lower than expected when historical reports are used for comparison.1 ,2 This finding is encouraging and should be an argument to support urgent diagnostic and therapeutic measures in patients with transient focal neurological deficits by dedicated specialised units. Second, the study gives another argument that the ABCD2 score for risk evaluation needs refinement.4 For instance, the ABCD2 score does not take vessel imaging into account. Thereby, patients may be missed who need timely treatment of carotid artery stenosis. Symptomatic carotid stenosis is one of the strongest risk factors for early risk of recurrence.5 Third, brain imaging is more than mere verification of ischaemic infarct. The infarct pattern deserves consideration. In this registry, patients with multiple acute infarctions had a recurrence rate nearly twice as high (compared with those with a single acute infarction). In another study, multiple infarct pattern was also a strong risk indicator for new brain lesions on follow-up imaging.6 Findings on imaging will get increasingly important and will stress superiority of MRI over CT.

Implications for practice

Owing to their temporary nature, transient focal neurological deficits may escape both patients’ and physicians’ attention easily. Nevertheless, urgent evaluation by stroke specialists may reduce the risk of subsequent stroke, myocardial infarction and deaths by timely establishment of secondary prevention measures. Identification and adequate treatment of carotid stenosis is important in particular.

References

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Footnotes

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.