Table 6. Atherothrombus (A) ASCOD Classification with Causality Grades [8].

A table was created representing the different causality grades, as an underlying etiology of ischemic stroke as per a subcategory of the ASCOD classification [8].

A: atherothrombosis; MR-DWI: magnetic resonance diffusion-weighted imaging; US-Duplex: ultrasound duplex; CTA: computed tomography angiography; MRA: magnetic resonance angiography; XRA: X-ray angiography; US-TCD: ultrasound transcranial Doppler; TEE: transesophageal echocardiography.

The Causality Grades [8]	ASCOD Atherothrombosis (A) Phenotypes According to Classification [8]
A1: potentially causal. A stroke that is atherothrombotic is defined as one of the following:	An ipsilateral atherosclerotic stenosis of 50-99% in an intracranial or extracranial artery supplying the ischemic field.	An ipsilateral atherosclerotic stenosis <50% in an intracranial or extracranial artery with an endoluminal thrombus supplying the ischemic field.		A mobile thrombus in the aortic arch.		An ipsilateral arterial occlusion in an intracranial or extracranial artery with evidence of underlying atherosclerotic plaque supplying the ischemic field.
A2: the causal link is uncertain. Defined as potentially one of the following:	An ipsilateral atherosclerotic stenosis of 30-50% in an intracranial or extracranial artery supplying the ischemic field.	An aortic plaque ≥ 4 mm without a mobile lesion.
A3: the causal link is unlikely, but the disease is present. One or more of the following may be seen:	A plaque (stenosis <30%) in an intracranial or extracranial artery, which is ipsilateral to the infarct area.	An aortic plaque <4 mm without a mobile thrombus.	A stenosis of any degree that is not supplying the infarct area.		A present history of myocardial infarction, coronary revascularization, or peripheral arterial disease.		An ipsilateral or bilateral atherosclerotic stenosis of 50–99% with bihemispheric MR-DWI lesion present.
A0: atherosclerosis is not detected. In order to rule out atherosclerosis, the following should be looked for:	A negative finding for an extracranial arterial stenosis on US-duplex, CTA, MRA, XRA, or autopsy.	A negative finding for an intracranial arterial stenosis on US-TCD, CTA, MRA, XRA, or autopsy.	A negative finding for an aortic arch atheroma: TEE or CTA with specific assessment of the aortic arch.
A9: an incomplete workup done on the patient. There will be a lack of tests performed such as the following:	US-duplex, US-TCD or CTA, or MRA, or XRA or autopsy has not been performed.	The minimum workup is extra- and intracranial assessment of the cerebral arteries.	The maximum workup also includes TEE and CTA of the aortic arch.