Acute ischaemic stroke: thrombolysis within 4.5 hours
The case
A 58-year-old man with a 30 pack-year smoking history and treated hypertension presents 2.5 hours after sudden-onset left hemiparesis, left homonymous hemianopia and left-sided neglect. Blood pressure is 165/92 mmHg, heart rate 82/min in sinus rhythm, and the NIHSS is 14. Non-contrast CT brain shows loss of grey-white differentiation in the right middle cerebral artery territory (ASPECTS 8) with no haemorrhage. Blood glucose is 6.2 mmol/L. There is no recent trauma, bleeding disorder or surgery in the past 3 months. What is the most appropriate immediate management?
Options
- AIntravenous alteplase 0.9 mg/kg
- BCT angiography and perfusion first
- CAspirin 300 mg then MRI brain
- DIntravenous labetalol for blood pressure
- EStroke unit admission then aspirin 100 mg daily
Think it through before you read on. Which single option is best, and why are the other four wrong?
Show the answer and explanation
Answer
A. Intravenous alteplase 0.9 mg/kg
Why this is the right answer
This man meets every criterion for intravenous thrombolysis. He has a disabling ischaemic stroke (NIHSS 14), the CT shows no haemorrhage, he is within 4.5 hours of onset, and there are no contraindications such as recent surgery, bleeding disorder, anticoagulant use or blood pressure above 185/110 mmHg.
The Australian and New Zealand Living Clinical Guidelines for Stroke Management (Stroke Foundation) recommend alteplase 0.9 mg/kg (maximum 90 mg), 10% as a bolus and the rest over 60 minutes, as soon as possible for eligible patients [VERIFY]. Tenecteplase is now an accepted alternative in many Australian centres [VERIFY]. The benefit falls with every minute of delay.
An ASPECTS of 8 means early ischaemic change in only 2 of 10 regions, which does not exclude thrombolysis. Extensive change (ASPECTS below 6 or more than one third of the MCA territory) would raise the bleeding risk.
CT angiography should be done to look for a large vessel occlusion that would qualify for endovascular thrombectomy, but it is done at the same time as, or immediately after, starting alteplase, never instead of it.
Blood pressure of 165/92 mmHg is below the 185/110 mmHg treatment threshold, so no antihypertensive is needed. Lowering it aggressively would reduce blood flow to the penumbra.
Why the other options are wrong
- B
Angiography is important for thrombectomy planning but must not delay alteplase in an eligible patient.
- C
Aspirin is withheld for 24 hours after thrombolysis, and MRI would waste time.
- D
His pressure is already below 185/110; lowering it further harms the penumbra.
- E
Observation alone in a thrombolysis-eligible patient is inadequate; every minute costs neurons.
High-yield takeaway
Ischaemic stroke within 4.5 hours, no haemorrhage, no contraindications, BP under 185/110: give alteplase now and image the vessels while it runs.
Reference: Stroke Foundation Australian and New Zealand Living Clinical Guidelines for Stroke Management (2024)
Common questions
What is the time window for stroke thrombolysis?
Within 4.5 hours of symptom onset, or of the time the patient was last known to be well.
What blood pressure rules out thrombolysis?
Above 185/110 mmHg. It must be brought below that before the drug is given, without dropping it aggressively.
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