Table 1.

Summary of ischemic stroke classification systems

	TOAST [2]	CCS [4]	ASCO [3]
Year published	1993	2007	2009
Classification type	Causative	Causative and phenotypic	Phenotypic
Subgroups	1) Large artery atherosclerosis 2) Cardioembolic 3) Small vessel occlusion 4) Other determined 5) Undetermined	1) Large artery atherosclerosis 2) Cardio-aortic embolism 3) Small artery occlusion 4) Other determined 5) Undetermined causes	1) Atherothrombosis 2) Small vessel occlusion 3) Cardiac pathology 4) Other determined
Sub-categories for undetermined cause	• Two or more causes identified • Negative evaluation • Incomplete evaluation	• Cryptogenic embolism • Other cryptogenic • Incomplete evaluation • Unclassified	•N/A
Required diagnostics	• Not specified	• Brain CT/MRI • ECG • Echocardiogram • Extra- and intracranial vessel imaging	• Incorporates completeness of the diagnostic evaluation into subtype assignment
Comments	• Simple • Widely used in clinical practice and medical literature	• Web-based application • Uses evidence-based criteria • Validated in multiple studies	• Assigns a level of likelihood to all potential causes • Describes multiple phenotypes

ASCO atherosclerosis, small vessel disease, cardiac source, other cause, CCS Causative Classification of Stroke System, CT computed tomography, ECG electrocardiogram, MRI magnetic resonance imaging, TOAST Trial of Org 10,172 in Acute Stroke Treatment study