Stroke Code 2026: Extended tPA Window and Thrombectomy Updates

Executive Summary

The 2026 American Heart Association/American Stroke Association guidelines represent a paradigm shift in acute ischemic stroke management. Based on landmark trials including EXTEND, DAWN, DEFUSE-3, and SELECT-2, these updates dramatically expand treatment windows for both intravenous thrombolysis and mechanical thrombectomy, potentially benefiting thousands of additional patients annually.

What's Changed: Major Updates

Time is Brain: Understanding the Windows

Traditional 4.5-Hour Window (Standard tPA)

For patients presenting within 4.5 hours of symptom onset with no contraindications:

• No advanced imaging required (CT head to rule out hemorrhage is sufficient)
• Fastest pathway to treatment
• Best outcomes when given within 90 minutes (door-to-needle time)
• Number needed to treat (NNT): 4-7 for excellent outcome

Extended Window: 4.5-9 Hours (Perfusion-Guided tPA)

Based on the EXTEND trial, patients 4.5-9 hours from onset may benefit if imaging shows salvageable tissue:

Imaging Requirements

• CT perfusion or MRI perfusion required
• Mismatch ratio ≥1.2 (penumbra/core)
• Ischemic core <70 mL
• Mismatch volume ≥10 mL

Eligibility Criteria

• Age 18-80 years (extended from previous upper limit)
• NIHSS 4-26
• Pre-stroke mRS 0-1 (functionally independent)
• No contraindications to tPA

Outcomes

• NNT: 10 for excellent outcome (mRS 0-1 at 90 days)
• Symptomatic ICH rate: 6.2% (comparable to standard window)
• 35% increase in treatment-eligible patients

Wake-Up Strokes (Unknown Onset Time)

Approximately 25% of strokes occur during sleep. The WAKE-UP trial established MRI-based selection:

MRI Criteria (DWI-FLAIR Mismatch)

• Positive DWI (diffusion-weighted imaging shows acute infarct)
• Negative FLAIR (fluid-attenuated inversion recovery shows no signal)
• Interpretation: Stroke occurred <4.5 hours ago (FLAIR takes 4-6 hours to become positive)

Treatment

• Standard dose alteplase (0.9 mg/kg, max 90 mg)
• Same contraindications as known-onset strokes
• Outcomes comparable to standard window treatment

Mechanical Thrombectomy: Expanded Indications

Standard Window: 0-6 Hours

Indications:

• Large vessel occlusion (LVO): ICA, M1, M2, basilar artery
• NIHSS ≥6
• ASPECTS ≥6
• Pre-stroke mRS 0-1
• No extensive early infarct signs

Extended Window: 6-24 Hours

Based on DAWN and DEFUSE-3 trials, select patients benefit from late thrombectomy:

Clinical-Core Mismatch (DAWN Criteria)

Group A:

• Age ≥80 years
• NIHSS ≥10
• Core <21 mL

Group B:

• Age <80 years
• NIHSS ≥10
• Core <31 mL

Group C:

• Age <80 years
• NIHSS ≥20
• Core 31-51 mL

Perfusion Mismatch (DEFUSE-3 Criteria)

• Mismatch ratio ≥1.8
• Mismatch volume ≥15 mL
• Core <70 mL

Outcomes

• NNT: 2.8 for functional independence (DAWN trial)
• 45% vs 17% achieved mRS 0-2 (thrombectomy vs medical management)
• Symptomatic ICH: 6%

Large Core Infarcts (SELECT-2 Trial)

Previously, large core infarcts (ASPECTS 3-5) were considered contraindications. SELECT-2 changed this:

Inclusion Criteria

• ASPECTS 3-5
• Large vessel occlusion (ICA or M1)
• Within 24 hours of last known well
• Age 18-85 years
• Pre-stroke mRS 0-2

Results

• 20% vs 7% achieved mRS 0-2 (thrombectomy vs medical)
• NNT: 8 for functional independence
• Mortality: 26% vs 38% (thrombectomy vs medical)

Emergency Department Stroke Protocol

Initial Assessment (Target: 10 Minutes)

FAST-ED Screen

• Facial droop
• Arm weakness
• Speech difficulty
• Time of onset
• Eye deviation (new - suggests LVO)
• Denial/neglect (new - suggests LVO)

Vital Signs

• Blood pressure (both arms)
• Heart rate and rhythm
• Oxygen saturation
• Temperature
• Blood glucose (treat if <60 or >400 mg/dL)

NIHSS Score

National Institutes of Health Stroke Scale (0-42 points):

• 0-4: Minor stroke
• 5-15: Moderate stroke
• 16-20: Moderate-severe stroke
• 21-42: Severe stroke

NIHSS ≥6 suggests large vessel occlusion (sensitivity 66%, specificity 87%)

Imaging (Target: 20 Minutes from Arrival)

Non-Contrast CT Head (Required for All)

Purpose: Rule out hemorrhage, assess early infarct signs

• Hyperdense vessel sign (acute thrombus)
• Loss of gray-white differentiation
• Sulcal effacement
• ASPECTS score (10-point scale, 1 point deducted per region)

CT Angiography (CTA)

Indications:

• NIHSS ≥6 (possible LVO)
• Any patient being considered for thrombectomy
• Posterior circulation symptoms

Identifies: Location and extent of occlusion, collateral flow

CT Perfusion (CTP)

Indications:

• Presentation 4.5-9 hours (for extended tPA window)
• Wake-up stroke (if MRI unavailable)
• Extended thrombectomy window (6-24 hours)

Measures:

• Core: Irreversibly infarcted tissue (CBF <30% of normal)
• Penumbra: At-risk but salvageable tissue (Tmax >6 seconds)
• Mismatch: Penumbra/core ratio

MRI Brain

Advantages: More sensitive for small infarcts, posterior circulation strokes

Disadvantages: Takes longer (20-30 minutes), not available at all centers

Key sequences:

• DWI: Shows acute infarct (bright signal)
• FLAIR: Becomes positive 4-6 hours after onset
• GRE/SWI: Detects hemorrhage
• MRA: Vessel imaging

Laboratory Tests

• Glucose: Hypoglycemia can mimic stroke
• CBC: Platelet count (if thrombocytopenic, may affect treatment)
• PT/INR, aPTT: If on anticoagulation
• Troponin: Rule out MI (common stroke mimic/comorbidity)
• Pregnancy test: Women of childbearing age

Do NOT delay imaging or treatment for lab results unless patient on anticoagulation

Alteplase (tPA) Administration

Dosing

• 0.9 mg/kg (maximum 90 mg)
• 10% bolus over 1 minute
• 90% infusion over 60 minutes

Absolute Contraindications

• Intracranial hemorrhage on imaging
• Significant head trauma or stroke within 3 months
• Intracranial/spinal surgery within 3 months
• GI bleed within 21 days
• Active internal bleeding
• Intracranial neoplasm, AVM, or aneurysm
• Suspected aortic dissection
• Acute bleeding diathesis

Relative Contraindications (Individualize Risk/Benefit)

• Minor or rapidly improving symptoms
• Seizure at onset with postictal residual
• Recent major surgery (<14 days)
• Recent GI or GU hemorrhage (<21 days)
• Recent MI (<3 months)
• Pregnancy

Blood Pressure Management

Before tPA:

• Target: BP <185/110 mmHg
• Labetalol 10-20 mg IV or nicardipine infusion
• Recheck every 15 minutes

During and after tPA (24 hours):

• Target: BP <180/105 mmHg
• Check BP every 15 minutes × 2 hours, then every 30 minutes × 6 hours, then hourly × 16 hours

Monitoring During Infusion

• Neurological checks every 15 minutes
• If sudden worsening: STOP infusion, emergent CT head, consider neurosurgery consult
• No anticoagulation or antiplatelet agents for 24 hours
• No NG tubes, Foley catheters, or arterial punctures during infusion

Mechanical Thrombectomy Workflow

Activation Criteria

• NIHSS ≥6
• CTA confirms large vessel occlusion
• Within appropriate time window (0-24 hours with imaging selection)
• Pre-stroke functional independence (mRS 0-2)

Preparation

• Activate interventional neuroradiology team immediately
• NPO status (may need general anesthesia)
• Two large-bore IVs
• Consent (patient or family)
• Continue tPA if already started (bridging therapy)

Anesthesia Considerations

• Conscious sedation preferred (allows neuro monitoring)
• General anesthesia if patient agitated or unable to cooperate
• Maintain BP to preserve collateral flow

Post-Treatment Management

ICU Monitoring (24 Hours)

• Neurological checks every 1-2 hours
• Blood pressure control (see targets above)
• Cardiac monitoring (atrial fibrillation common)
• Glucose control (target 140-180 mg/dL)
• Temperature control (treat fever aggressively)

Repeat Imaging

• 24 hours post-tPA: CT head before starting antiplatelet/anticoagulation
• If neurological worsening: Emergent CT head
• MRI brain: Within 24-48 hours for final infarct assessment

Secondary Prevention

Antiplatelet Therapy

• Aspirin 325 mg: Start 24 hours after tPA (or immediately if no tPA given)
• Dual antiplatelet therapy (DAPT): Aspirin + clopidogrel for 21 days for minor stroke/TIA (NIHSS ≤3)

Anticoagulation

• Atrial fibrillation: Start anticoagulation after 4-14 days (timing depends on infarct size)
• Options: Apixaban, rivaroxaban, dabigatran, warfarin

Statin Therapy

• High-intensity statin: Atorvastatin 80 mg or rosuvastatin 40 mg
• Start immediately regardless of cholesterol level

Blood Pressure

• Target <130/80 mmHg after acute period
• ACE inhibitor or ARB preferred

Special Situations

Posterior Circulation Strokes

• Basilar artery occlusion: high mortality (70-90% without treatment)
• Lower threshold for thrombectomy (consider even with NIHSS <6)
• Extended time windows (up to 24 hours) more commonly applied
• Symptoms: vertigo, diplopia, ataxia, crossed findings

Patients on Anticoagulation

Warfarin

• INR <1.7: Eligible for tPA
• INR ≥1.7: Give 4-factor PCC (prothrombin complex concentrate) to reverse, then tPA

Direct Oral Anticoagulants (DOACs)

• Last dose >48 hours ago: Eligible for tPA
• Last dose <48 hours ago: Consider reversal agent (idarucizumab for dabigatran, andexanet alfa for Xa inhibitors)

Pregnancy

• tPA is relatively contraindicated but can be given if benefit outweighs risk
• Mechanical thrombectomy preferred (no systemic thrombolytic)
• Multidisciplinary decision (neurology, OB, patient/family)

Stroke Mimics

Approximately 20-30% of suspected strokes are mimics. Common mimics include:

Hypoglycemia

• Check glucose immediately in all patients
• Focal deficits can occur with glucose <50 mg/dL
• Treat and reassess before imaging

Seizure (Todd's Paralysis)

• Postictal weakness can last hours
• History of seizure disorder
• Witnessed seizure activity

Hemiplegic Migraine

• History of similar episodes
• Younger patients
• Gradual onset (vs sudden stroke)
• Headache prominent

Conversion Disorder

• Inconsistent exam findings
• Non-anatomic deficits
• Psychiatric history

Bell's Palsy

• Forehead involvement (stroke spares forehead)
• No other neurological deficits

Quality Metrics and Goals

Door-to-Needle Time

• Goal: <60 minutes
• Best practice: <45 minutes
• Every 15-minute delay increases odds of poor outcome by 4%

Door-to-Groin Time (Thrombectomy)

• Goal: <90 minutes
• Best practice: <60 minutes

Imaging-to-Needle Time

• Goal: <20 minutes

Common Pitfalls

Pitfall #1: Waiting for Lab Results

Problem: Delaying imaging/treatment for non-essential labs

Solution: Only wait for labs if patient on anticoagulation; glucose can be point-of-care

Pitfall #2: Dismissing Minor Symptoms

Problem: Not activating stroke code for NIHSS <5

Solution: Minor strokes can have devastating consequences; treat all suspected strokes urgently

Pitfall #3: Missing Posterior Circulation Strokes

Problem: Attributing vertigo/ataxia to benign causes

Solution: High index of suspicion; use HINTS exam (Head Impulse, Nystagmus, Test of Skew)

Pitfall #4: Rigid Adherence to Time Windows

Problem: Excluding patients who might benefit from extended window treatment

Solution: Use perfusion imaging to identify salvageable tissue beyond traditional windows

Key Takeaways

1. Time is brain: Every minute counts—streamline your stroke protocol
2. Extended windows exist: Don't automatically exclude patients beyond 4.5 hours
3. Perfusion imaging expands eligibility: CT/MR perfusion can identify candidates up to 24 hours
4. Wake-up strokes are treatable: Use DWI-FLAIR mismatch on MRI
5. Large vessel occlusions need thrombectomy: NIHSS ≥6 should trigger CTA
6. Large cores can benefit: ASPECTS 3-5 no longer absolute contraindication
7. Blood pressure control is critical: <185/110 before tPA, <180/105 after
8. Don't wait for labs: Only essential tests are glucose and coagulation studies (if indicated)

References

1. Powers WJ, et al. Guidelines for the Early Management of Patients With Acute Ischemic Stroke: 2026 Update. Stroke. 2026;57:e1-e99.
2. Ma H, et al. Thrombolysis Guided by Perfusion Imaging up to 9 Hours after Onset of Stroke (EXTEND). N Engl J Med. 2019;380:1795-1803.
3. Nogueira RG, et al. Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct (DAWN). N Engl J Med. 2018;378:11-21.
4. Albers GW, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging (DEFUSE-3). N Engl J Med. 2018;378:708-718.
5. Sarraj A, et al. Trial of Endovascular Thrombectomy for Large Ischemic Strokes (SELECT-2). N Engl J Med. 2023;388:1259-1271.