Director & Chief - Neurointerventional Surgery, Artemis Hospitals, Gurgaon, India
Part 4 of 14 in Role of Neuro Intervention
The FAST Acronym and the Stroke Treatment Window: Why Every Minute Matters
August 9, 2026
Recognising a stroke quickly is what makes treatment possible at all. The FAST acronym summarises the warning signs: Facial drooping that occurs suddenly, Arm weakness where the arm drops, Speech disturbance that comes on suddenly, and Time, meaning any sudden loss of a function that was previously normal should be treated as ischemic stroke until proven otherwise. A sudden, severe headache, described as the worst headache of the patient's life, or a sudden seizure, also requires urgent neuroimaging.
A CT scan or MRI is mandatory before treatment, because ischemic and haemorrhagic stroke cannot be reliably told apart on clinical examination alone. Once imaging confirms the type of stroke, the treatment pathway is clear: an intravenous thrombolytic drug should be given if the patient qualifies, with fresh surgery and intracerebral haemorrhage as the only absolute contraindications, and for large vessel occlusion, intra-arterial mechanical thrombectomy follows.
The treatment windows are specific. Intravenous thrombolysis must be given within 4.5 hours of symptom onset. Mechanical thrombectomy has a window of 6 hours in standard cases, extending up to 24 hours in carefully selected cases identified on advanced imaging, based on the DAWN and DEFUSE trials. Current 2026 guidelines for mechanical thrombectomy require a pre-stroke modified Rankin Scale of 0 to 1, a confirmed large vessel occlusion, age above 18, an NIHSS score above 6, and an ASPECTS score above 6.
Because these windows are so narrow, acute stroke care has to be built close to where patients live. A patient using a drip-and-ship pathway, receiving initial thrombolysis locally before transfer, generally needs to reach a thrombectomy-capable centre within 4 to 5 hours, or up to 6 hours in selected cases; beyond that, the distance itself becomes the deciding factor in outcome, which is why Dr. Matin stresses that acute stroke treatment cannot depend on a distant specialist hospital.
This guide is based on a live Jivo Masterclass — Dr. Tariq Matin taught doctors across Africa on August 9, 2026.
FROM THE LIVE Q&A
Dr. Chingis, Kazakhstan
When evaluating an intracranial haematoma that needs evacuation, is it done manually or with robotic or stereotactic guidance?
Dr. Tariq Matin
Not all intracranial haemorrhages require surgical evacuation — most are managed medically. When the bleed is causing raised intracranial pressure, because the brain is inside a closed skull and any extra volume risks herniation, we have to evacuate it. There are several techniques — minimally invasive surgery, stereotactic drainage, or open decompressive surgery — and that's the neurosurgeon's domain. Our endovascular role is in identifying and occluding the underlying vascular cause, the aneurysm or AVM, that caused the bleed in the first place.
Frequently Asked Questions
How do you gain access to occluded vessels in the deeper structures of the brain?▼
Think of it like a blocked drainage system under a city. A surgeon's approach is to dig down from outside to reach the blockage. Our approach is to enter the drainage system from where it begins and navigate a map through the system to the blockage, clearing it from within — you don't have to dig the ground. Access is through a needle puncture in the groin or wrist, and from there the catheters track through the blood vessels all the way to the brain.
How do you manage older patients?▼
Age is not a criterion for us. We have treated patients in their 90s and even at 100 years of age and seen them recover. Age alone is never a reason to withhold intervention.
What are the risk factors for developing aneurysms?▼
The key risk factors are hypertension and smoking. Blood hits the vessel wall repeatedly, the wall weakens and bulges into an aneurysm, and the body tries to repair itself — but if blood pressure is chronically elevated, or tobacco smoke is weakening the vessel wall, or there's an underlying genetic factor causing weak collagen, that repair mechanism gets overwhelmed and the aneurysm develops over time. This is different from AVMs, which are congenital and present from birth — aneurysms are acquired lesions that develop over a lifetime.
What is severe carotid stenosis?▼
We're usually talking about narrowing at the carotid bifurcation in the neck, where the common carotid artery splits into the external carotid, supplying the face, and the internal carotid, supplying the brain. Stenosis of 50% or more on catheter angiography, or 60% or more on non-invasive imaging like CT or MR angiography, is considered significant and needs treatment. When we say severe stenosis, we mean 70% to 99% narrowing.
How do you decide between coiling, stent-assisted coiling, flow diversion, and surgical clipping for an aneurysm?▼
We work as a multidisciplinary team with a very respectful relationship with our neurosurgical colleagues. For aneurysms where both approaches are feasible, endovascular coiling is preferred under current guidelines, but we don't impose that on patients. We hold a multidisciplinary meeting, review the morphology together, discuss which endovascular option — coil, stent-assisted coil, or flow diversion — is most appropriate, and then meet the patient's family and explain the complexity, risk, and cost of each option in full so they can make an informed decision.
What are the DAWN and DEFUSE trials, and how do they affect the thrombectomy window?▼
These trials provide the evidence base for extending the mechanical thrombectomy window up to 24 hours in carefully selected cases identified on advanced imaging, beyond the standard 6-hour window.
What are the 2026 guideline criteria for mechanical thrombectomy eligibility?▼
Current guidelines require a pre-stroke modified Rankin Scale of 0 to 1, a confirmed large vessel occlusion, age above 18, an NIHSS score above 6, and an ASPECTS score above 6.
What is the treatment window for intravenous thrombolysis compared with mechanical thrombectomy?▼
Intravenous thrombolysis must be given within 4.5 hours of symptom onset, while mechanical thrombectomy has a window of 6 hours in standard cases, extending up to 24 hours in selected imaging-positive cases.
What are the only absolute contraindications to intravenous thrombolytic treatment?▼
Fresh surgery and intracerebral haemorrhage are the only absolute contraindications; everything else is a relative consideration.
In This Series: Role of Neuro Intervention
- 1.Role of Neuro Intervention
- 2.The History of Neurointervention: From the Seldinger Technique to Modern Stroke Care
- 3.Mechanical Thrombectomy for Ischemic Stroke: How It Works and Why It Matters
- 4.The FAST Acronym and the Stroke Treatment Window: Why Every Minute Matters
- 5.Carotid and Intracranial Stenting: Preventing a Second Stroke
- 6.How Severe Does Carotid Stenosis Need to Be Before It Needs Treatment?
- 7.Cerebral Venous Thrombosis: An Under-Diagnosed Cause of Stroke
- 8.Brain Aneurysms and Subarachnoid Haemorrhage: Surgical Clipping vs Endovascular Coiling
- 9.Treating Complex Aneurysms: Balloon-Assisted Coiling, Stent-Assisted Coiling and Flow Diversion
- 10.AVM Embolisation: Treating Lobar Brain Bleeds
- 11.What Causes Brain Aneurysms? Hypertension, Smoking and Other Risk Factors
- 12.Is There an Age Limit for Stroke or Aneurysm Treatment?
- 13.Which Stroke and Aneurysm Patients Can Safely Travel Abroad for Treatment?
- 14.Can the Brain Recover After Stroke or Haemorrhage? What to Expect