【Cerebral Infarction Treatment】4.5 Hours from Onset: A Matter of Life and Death! Explanation of rt-PA and Thrombectomy

Cerebral infarction treatment demands extremely rapid decision-making and action, based on the principle that “Time equals Brain.” The time elapsed since onset drastically changes which treatments can save a life and minimize long-term disabilities. Crucially, contemporary standard treatment focuses intensive, powerful therapies during the immediate hours following onset.

Cerebral Infarction Treatment Timeline

Time from Onset	Treatment Option (Japan 2025)	Eligibility and Estimated Success Rate
0−4.5 Hours	① rt-PA (Alteplase) Intravenous Therapy ② Thrombectomy (Alone or combined with rt-PA)	The Golden Time for the ultra-acute phase.
4.5−9 Hours (Extended up to 24 hours for some)	Thrombectomy (Mechanical Clot Retrieval)	When large vessel occlusion is confirmed by imaging.
9−24 Hours	Thrombectomy (Only for selected patients)	If DAWN/DEFUSE-3 criteria are met (based on imaging).
≥24 Hours	Acute treatment ends → Focus shifts to prevention and rehabilitation.	–

1. Ultra-Acute Phase Treatment (Onset to within a Few Hours)

Treatment Method	Content	Indication and Effect (Quantified)	Main Risks
rt-PA IV Therapy(Thrombolytic Drug)	A clot-dissolving drug (Alteplase) administered via IV drip.	Within 4.5 hours of onset. Subject to strict criteria (severity, age, etc.). Effect: 3 months later, the probability of returning to daily life with minimal disability increases by ≈1.5times.	Intracerebral hemorrhage(≈5−6%) → Requires strict eligibility assessment.
Thrombectomy(Mechanical Clot Retrieval)	A catheter is inserted from the groin and used to directly suction or grip and remove the clot.	Blockage of a large vessel (Internal Carotid Artery / Middle Cerebral Artery M1 segment). Currently extended to selected patients up to 24hours post-onset in 2025.	Effect: 3 months later, the probability of walking/being independent leaps up by 2−4times (especially in severe cases).

2025 Reality:

“rt-PA + Thrombectomy” double treatment is available at specialized hospitals (Comprehensive Stroke Centers, CSCs, approx. 900 nationwide).
The primary protocol for an ambulance is “direct transport to a hospital capable of thrombectomy” (Bypass transport).

2. Acute to Recovery Phase Treatment (During Hospitalization)

Purpose	Main Treatment Content
Brain Edema Management	IV drip of Mannitol, Glycerol. Craniotomy decompression surgery if severe.
Blood Pressure Management	Often kept slightly elevated (180−200 mmHg) during the first 24−48 hours → to deliver blood to the brain tissue distal to the blockage.
Initiation of Secondary Prevention	Cardioembolic: Anticoagulants (DOAC or Heparin) started immediately. Lacunar/Atherothrombotic: Antiplatelet drugs (Aspirin + Clopidogrel, etc.).
Pneumonia Prevention	Early mobilization, swallowing assessment, gastronomy tube placement if necessary.

3. Secondary Prevention Medication (Lifelong Continuation after Discharge)

Type of Cerebral Infarction	First-Line Medication (As of 2025)
Lacunar Infarction	Cilostazol OR Aspirin + Clopidogrel
Atherothrombotic Infarction	Aspirin OR Clopidogrel + Statin (Mandatory)
Cardioembolic Infarction	DOACs (Rivaroxaban, Apixaban, Edoxaban, Dabigatran) are the first choice. Warfarin is largely a historical drug.

4. Rehabilitation

Timing	Content
Immediately after onset ∼1 Week	Prevention of bed rest complications, prevention of joint contractures, sitting practice.
1−4 Weeks	Start of full-scale rehabilitation (Physical, Occupational, Speech Therapy). Insurance coverage up to a maximum of 3 hours per day (9 units).
3−6 Months	Peak of recovery (The first 3 months see the greatest improvement).
≥6 Months	Maintenance rehabilitation (via long-term care insurance, weekly sessions).

Latest Topics

Thrombectomy extended up to 24 hours (DAWN and DEFUSE-3 criteria).
Tenecteplase (A newer thrombolytic drug) started being used in some facilities (Potentially more effective and lower bleeding risk than rt-PA).
AI-driven rapid imaging diagnosis (Determining the blocked vessel and the amount of salvageable brain in seconds).

Summary

0−4.5 Hours → rt-PA IV drip.
Large vessel occlusion → Thrombectomy (Possible up to 24 hours).
After the acute window → Secondary prevention drugs + Intensive rehabilitation.