Acute stroke management: tPA criteria, thrombectomy and secondary prevention
RezzyManaging an acute ischemic stroke is all about the "time is brain" mantra. We have a very tight window to save that penumbra (the salvageable brain tissue around the core infarct), so let's break down the hyperacute management and how we prevent the next one.
1. Thrombolysis with IV tPA (Alteplase/Tenecteplase)
The goal here is to dissolve the clot and restore flow.
- The Window: Generally within 3 hours of "last known well" time. This can be extended to 4.5 hours in certain patients (though the 3-4.5 hour window has more stringent exclusion criteria).
- Blood Pressure Goal: Must be
< 185/110 mmHgbefore starting tPA.
I've put together a table of the absolute "no-go" zones for tPA, as these are high-yield for the USMLE.
| Category | Absolute Contraindications (Exclusion Criteria) |
|---|---|
| Hemorrhage | Any history of intracranial hemorrhage; active internal bleeding |
| Recent Trauma/Surgery | Intracranial/intraspinal surgery or head trauma within 3 months |
| Blood Pressure | Uncontrolled hypertension (>185/110 mmHg) |
| Coagulopathy | Platelets < 100,000; Heparin within 48h with elevated aPTT; Current anticoagulant use with elevated INR (>1.7) |
| Imaging | Evidence of hemorrhage on CT; Multilobar infarction (>1/3 of cerebral hemisphere) |
| Other | Intracranial neoplasm, AV malformation, or aneurysm |
2. Mechanical Thrombectomy
If there is a Large Vessel Occlusion (LVO)—like the internal carotid or the proximal middle cerebral artery (M1 segment)—tPA might not be enough.
- The Window: Usually within 6 hours of symptom onset.
- Extended Window: Can be up to 24 hours if there is a significant mismatch between the clinical deficit and the infarct size on perfusion imaging (DAWN or DEFUSE-3 trial criteria).
- Note: Patients can receive both tPA and thrombectomy if they meet criteria for both.
3. Secondary Prevention
Once the dust settles, we have to make sure this doesn't happen again. The strategy depends on the etiology (the "TOAST" classification).
- Antiplatelets:
- Non-cardioembolic stroke: Aspirin, Clopidogrel, or Aspirin + Dipyridamole.
- Dual Antiplatelet Therapy (DAPT): Usually Aspirin + Clopidogrel for the first 21–90 days for minor stroke or high-risk TIA.
- Anticoagulation: If the cause is Atrial Fibrillation, we use DOACs (Apixaban, Rivaroxaban) or Warfarin.
- Statins: High-intensity statin (e.g., Atorvastatin 80 mg) regardless of baseline LDL.
- Blood Pressure: Long-term goal is usually
< 130/80 mmHg. - Carotid Endarterectomy (CEA): Indicated if there is symptomatic carotid stenosis > 70% (sometimes > 50% in men).
To help you visualize the workflow from the ER to the neuro-interventional suite, here is a flowchart of the decision-making process.
This is a lot to take in, but it's one of the most important protocols in neurology. Would you like to see some practice questions on this, or maybe some flashcards to help you memorize those tPA contraindications? They're a classic exam favorite!
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