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.
Cardiac sources of embolism can be evaluated as part of the work up with EKG monitoring and echocardiogram. Management
Pulse oximetry can guide the use of supplemental oxygen to maintain oxygen saturation greater than 94%. Hyperoxia should be avoided as may be detrimental in stroke. Hypertension is common in an acute ischemic stroke. A low BP is uncommon and may indicate symptoms exacerbation of a previous stroke due to poor perfusion. Blood pressure of 220/120 mmHg should receive treatment. There is a consensus approach of allowing permissive hypertension up to 220/120 mmHg for patients that are not candidates for thrombolysis. [21]
However, for a patient that is a potential candidate for alteplase, attempt to control BP should be made immediately as goal BP for initiation of IV alteplase is 185/110 mmHg. Usually, titratable short-acting intravenous hypotensive agents are recommended to avoid dropping the BP too much once the patient is at goal. Hypotensive agents that can be options include labetalol, nicardipine, clevidipine, hydralazine, enalaprilat. [21]
For the patients that present within the therapeutic window, the decision to treat with intravenous recombinant tissue plasminogen (less than 4.5 hours from symptom onset) or endovascular treatment with mechanical thrombectomy should be made. Initiation of IV alteplase treatment in the 3 to 4.5-hour window is the current recommendation for patients less than 80 years of age, no history of both diabetes mellitus and prior stroke, use of anticoagulants, and NIHSS score of less than 25. Only patients with disabling symptoms are considered eligible for thrombolytic treatment.