Wake-Up Stroke: Is the Patient 'Out of the Window'?

He is a wake-up stroke with unknown onset time, which is not the same as being outside the window. In a substantial minority of these patients the stroke occurred shortly before awakening, so a favorable imaging profile is common.

Two evidence-based routes exist, and they answer different questions:

1. CT angiography first. The highest-value decision is whether he has a large vessel occlusion, because that drives thrombectomy, which has a much larger treatment effect than thrombolysis. Get CTA now - it can run while you decide about MRI.
2. Penumbral or tissue-clock imaging. If CTA shows an occlusion, CT or MR perfusion defines core and mismatch for late-window thrombectomy (roughly 6–24 hours from last-known-well). If CTA is negative and he is within 4.5 hours of awakening, MRI showing DWI positivity with FLAIR negativity (DWI-FLAIR mismatch) supports intravenous thrombolysis.

Do not declare him ineligible on the basis of the clock alone. Equally, do not let the MRI queue delay a thrombectomy decision.

This is a favorable mismatch profile - core under about 70 mL, mismatch ratio well above 1.8, and a small core relative to a large at-risk territory - in a patient with a moderate deficit and good baseline function. Mechanical thrombectomy is indicated, and the imaging supports benefit well beyond 6 hours from last-known-well.

• Do not wait for MRI before calling the neurointerventional team; the 25 minutes is better spent in the angio suite.
• Thrombolysis can be considered as bridging if he is within 4.5 hours of awakening and has DWI-FLAIR mismatch; if FLAIR is already positive, skip the lytic and proceed directly to thrombectomy rather than losing time.
• Blood pressure: below 185/110 before a lytic, and below 180/105 afterward. His 172/94 currently qualifies either way - resist the reflex to drop him aggressively, since collaterals depend on perfusion pressure.
• Practical points: no delay for further laboratory results beyond glucose and INR, weight-based dosing checked, and groin access without waiting for a repeat CT.

Frame the family conversation around thrombectomy as the primary therapy, with the lytic as an adjunct.

This is a large core with essentially no salvageable penumbra, and the honest answer is that the expected benefit is much smaller and the risk of hemorrhagic transformation and malignant edema is higher.

The field has moved: recent randomized trials of thrombectomy in large-core infarcts (core up to roughly 100–150 mL by perfusion or ASPECTS 3–5) showed benefit over medical management alone, so "large core" is no longer an automatic exclusion. But the absolute benefit is attenuated, and the included patients were selected - often younger, with good baseline function, and without extensive established infarction on noncontrast CT.

So the decision is individualized:

• Re-examine the noncontrast CT. An ASPECTS of 10 with a 90 mL perfusion core is discordant; the CT may be underestimating established injury, or the CTP threshold may be overestimating it. Reconcile before committing.
• Weigh baseline function, age, comorbidities, and goals of care with the family - including the possibility of decompressive hemicraniectomy and the realistic chance of severe disability.
• No intravenous thrombolysis in this profile.

The wrong answers are reflexively proceeding as if this were a favorable mismatch, or reflexively declining without discussion.