ISCHEMIC STROKE / CLASSIFICATION
SSS-TOAST CLASSIFICATION OF ISCHEMIC STROKE
Created 26/09/2022, last revision 22/02/2023
- The SSS-TOAST classification is an evidence-based classification algorithm that reflects advances in stroke imaging and epidemiology [Ay, 2005]
- based on certain clinical and imaging criteria, each TOAST subtype is divided into 3 subcategories “certain”, “probable”, or “possible”
- the new algorithm refines the determination of the most likely etiology in the presence of multiple competing mechanisms
- an automated web-based version of the SSS-TOAST, the Causative Classification System (CCS), was developed to facilitate its utility in multicenter settings (Ay, 2007)
- CCS allows rapid analysis of patient data with excellent intra- and inter-examiner reliability when accurate subtyping is critical (trials)
- the purple text was not present in the original SSS-TOAST publication in 2005
→ ischemic stroke classification
→ TOAST criteria
→ Chinese ischemic stroke classification
SSS-TOAST 1 – Large Artery Atherosclerosis (LAA)
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SSS-TOAST 3 – Small-artery occlusion
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SSS-TOAST 4 – Other causes
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SSS-TOAST 5 – Undetermined causes
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- cryptogenic embolism → ESUS criteria
- vessel imaging findings suggesting embolic etiology:
- evidence of abrupt cutoff consistent with a blood clot within otherwise angiographically normal-looking intracranial arteries
- evidence of complete recanalization of the previously occluded artery
- presence of multiple acute infarctions that have occurred closely related in time without detectable abnormality in the relevant vessels
- vessel imaging findings suggesting embolic etiology:
- other cryptogenic strokes – those not fulfilling the criteria for cryptogenic embolism
- incomplete evaluation – the absence of diagnostic tests that would have been essential to uncover the underlying cause
- unclassified – the presence of >1 evident mechanism; either there is probable evidence for each, or no single cause can be reliably established