The National Institutes of Health Stroke Scale (NIHSS) is a standardized method for quantifiable assessment of stroke symptoms. It is the preferred scoring system, and scores range from 0 to 42. A patient with a higher score on this scale is more likely to be considered disabled; however, the definition of "disabling" depends on age, occupation, underlying life-limiting comorbidities, advance directives. The crucial step in the evaluation of stroke patients is to obtain brain imaging to ascertain the type and characteristics of the stroke. In this regard, non-contrast CT of the head is the imaging modality of choice. Ischemic changes may classify as acute, subacute, and chronic, depending on the time in which they present after the onset of stroke. CT scan can also rule out intracranial hemorrhage. [18] If an intracranial hemorrhage is present, aneurysmal rupture should be investigated given its association with arterial vasospasm resulting in stroke. [3] Anterior cerebral artery strokes could be missed on imaging studies depending on their location or size. One case series found that 37.5% (6 of 16) of ACA infarcts evaluated by CT were identifiable only after using contrast injection or angiography. If the area of hypodensity is small and localized over a sulcus, the infarct could be overlooked. [1] [13]  Noncontrast head CT should be quickly followed by CT angiography of the head and neck to expedite identification of intracranial large vessel occlusion.
The DAWN trial used clinical imaging mismatch (imaging from CTP or DW-MRI and NIHSS scoring) as criteria to select patients with anterior circulation LVO for MT between 6 and 24 hours from last known well. The trial demonstrated an overall functional benefit at 90 days in the treatment group (mRS score 0 to 2, 49% versus 13%, adjusted difference 33%, 95% CI, 21 to 44; a probability of superiority greater than 0.999). The DEFUSE 3 trial used perfusion core mismatch and maximum core size as criteria in selecting the patient for MT with LVO in anterior circulation 6 to 16 hours from last time seen normal. This trial also showed outcome benefit at 90 days in the treated group (mRS score 0 to 2, 44.6% vs. 16.7%, RR 2.67, 95% CI, 1.60 to 4.48, p greater than 0.0001). DAWN and DEFUSE 3 are the only trials showing a benefit of mechanical thrombectomy greater than 6 hours from symptoms onset. Only criteria from these trials should be viable for patient selection who might benefit from MT. [21] One should be aware that most of the patients involved in DAWN and DEFUSE 3 trials had middle cerebral artery occlusions. Beyond the acute management of stroke, the use of antihypertensives, dual antiplatelet therapy, anticoagulants, carotid endarterectomy should be used to prevent recurrent events. Antiplatelet therapy or anticoagulants are not recommended within 24h after alteplase administration. Aspirin is not a recommendation as a substitute for other interventions for acute stroke.