ISCHEMIC STROKE / CLASSIFICATION
SSS-TOAST CLASSIFICATION OF ISCHEMIC STROKE
Created 26/09/2022, last revision 04/09/2023
- the SSS-TOAST classification is an evidence-based classification algorithm that reflects advancements in stroke imaging and epidemiology [Ay, 2005]
- based on specific clinical and imaging criteria, each TOAST subtype is further categorized into on of three subcategories: “certain”, “probable”, or “possible”
- this new algorithm refines the determination of the most likely etiology, particularly when multiple competing mechanisms are present
- an automated web-based version of the SSS-TOAST, known as the Causative Classification System (CCS), was developed to facilitate its utilization in multicenter settings (Ay, 2007)
- CCS enables swift analysis of patient data with excellent intra- and inter-examiner reliability
- particularly valuable in situations where precise classification is of critical importance (such as in clinical trials)
- the text highlighted in purple was not included in the original SSS-TOAST publication in 2005
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
- vascular imaging indicative of an embolic origin:
- abrupt absence of contrast consistent with a blood clot within otherwise angiographically normal-appearing intracranial arteries
- complete recanalization of the previously occluded artery
- multiple acute infarcts occurring in a close temporal relationship, without apparent abnormalities in the relevant arteries
- vascular imaging indicative of an embolic origin:
- other cryptogenic strokes – those not meeting the criteria for cryptogenic embolism
- incomplete evaluation – the absence of essential diagnostic tests required to determine 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