Wake-Up Stroke With Large Vessel Occlusion
72-year-old woman is found by her family at 7 AM with right hemiparesis and aphasia. She was last known well at 10 PM the previous night (9 hours ago). NIH Stroke Scale score is 14. Noncontrast head CT shows no hemorrhage and early ischemic changes limited to the left insula. CT angiography shows a left M1 occlusion. CT perfusion shows a core of 25 mL, penumbra of 90 mL, and mismatch ratio of 3.6. Blood pressure 168/92 mm Hg, glucose 112 mg/dL. She has no contraindications to thrombolysis other than the time window. Family reports she was independent and lived alone.
1. Is she a candidate for IV thrombolysis? Explain your reasoning.
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No, she is outside the standard 4.5-hour window for IV thrombolysis. Her last known well was 9 hours ago. Wake-up strokes have an unknown onset, and IV thrombolysis is not routinely recommended unless advanced imaging (MRI DWI-FLAIR mismatch) suggests the stroke is within the treatment window. In this case, CT perfusion was obtained, but it is used primarily to select patients for mechanical thrombectomy, not to extend the thrombolysis window. The risk of symptomatic intracranial hemorrhage outweighs the benefit outside the window. Therefore, do not give IV alteplase or tenecteplase. Focus on mechanical thrombectomy.
2. Is she a candidate for mechanical thrombectomy? Apply trial criteria.
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Yes. She has a large vessel occlusion (left M1), a significant deficit (NIHSS 14), and a favorable imaging profile. She meets DEFUSE-3 criteria: last known well 6-16 hours, core infarct <70 mL, penumbra >15 mL, and mismatch ratio >1.8. She also meets DAWN criteria: 6-24 hours, NIHSS >=10, and core <31 mL. The core is 25 mL and penumbra is 90 mL, with a mismatch ratio of 3.6. She was independent before the stroke. Therefore, proceed with emergent mechanical thrombectomy at a comprehensive stroke center. Do not delay for thrombolysis. Transfer if necessary.
3. What if CT perfusion is unavailable? What alternative imaging would you use?
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If CT perfusion is unavailable, use noncontrast CT and CT angiography to assess for large vessel occlusion and exclude hemorrhage. For late-window selection, MRI with diffusion-weighted imaging and FLAIR can identify patients who may benefit from thrombolysis (DWI-FLAIR mismatch) and help estimate infarct core. Clinical-core mismatch using NIHSS and ASPECTS on noncontrast CT is an alternative, though less precise. In many centers, NCCT/CTA alone is sufficient to proceed with thrombectomy in patients with a clear large vessel occlusion and significant deficit, especially if transfer to a comprehensive center is needed. The decision should be individualized and made in consultation with neurology and neurointervention.