Alteplase for Acute Ischemic Stroke
A clinical evidence dashboard reviewing 10 landmark rt-PA studies (1995-2019), including major re-analyses that reshaped the risk-benefit conversation.
Jimmy Pruitt
PharmD
10
Studies
7,384+
Patients
10
RCTs
13
References
Alteplase (rt-PA) has been used for acute ischemic stroke since FDA approval in 1996 after publication of the NINDS trial. Subsequent landmark trials tested broader windows and different populations, while newer re-analyses challenged how confidently early benefit should be interpreted.
FDA Milestone
Approval occurred in 1996 based primarily on early NINDS data for treatment within 3 hours.
Time Sensitivity
Guideline benefit remains strongly time dependent, with earlier reperfusion generally associated with better outcomes.
Controversy
Baseline imbalances in pivotal trials and increased symptomatic ICH continue to fuel risk-benefit debate.
Re-analysis Era
Independent patient-level re-analyses of NINDS and ECASS III reduced certainty of efficacy after adjustment for baseline differences.
Mechanism of Action
Alteplase binds fibrin within thrombus and converts entrapped plasminogen to plasmin, promoting fibrinolysis and clot dissolution in acute ischemic stroke.
Weight-Based Dosing
Total Dose
0.9 mg/kg (max 90 mg)
Standard AIS thrombolytic dose
Administration Split
10% IV bolus over 1 min, then 90% infusion over 60 min
Administration and PK/PD
Route
IV only
Infusion Time
60 minutes
Half-life
~5 minutes
Primary Clearance
Hepatic/plasma
Adverse Effects
Major Contraindications
- • Active internal bleeding
- • Severe uncontrolled hypertension
- • Recent ischemic stroke (<3 months), except the current qualifying event
- • Concurrent pro-hemostatic reversal approach (avoid txa overlap)
Clinical Pearl
Dose preparation errors are avoidable high-risk events: confirm actual body weight, calculate total dose first, then explicitly separate bolus and infusion fractions before administration.
Evidence at a Glance
Study Types
Largest Cohorts
Outcome Pattern
Window + Safety
Most Reliable Window
≤3 hours
Extended Window
3-4.5h selected patients; imaging-guided late presenters
Safety Signal
Symptomatic ICH increases in several pivotal trials despite functional benefit in select cohorts.
Alteplase 0.9 mg/kg within 3 hours vs placebo.
Clinical Significance
Foundational trial for approval. Functional benefit signal came mainly from Part 2, while early neurologic endpoint in Part 1 was neutral, creating a mixed interpretation even before re-analysis work.
Higher-dose alteplase (1.1 mg/kg max 100 mg) within 6 hours vs placebo.
Clinical Significance
Demonstrated how dose and selection can shift net effect toward harm. Mortality signal remains one of the most cautionary thrombolysis findings.
Alteplase within 6 hours vs placebo in moderate stroke severity.
Clinical Significance
A key neutral trial in extended windows. Reinforced that hemorrhagic risk can persist even when global functional outcomes are unchanged.
Alteplase 3-5 hours after onset vs placebo.
Clinical Significance
Helped define the limits of late-window thrombolysis before advanced imaging selection became standard.
Part A extension trial up to 6 hours after onset.
Clinical Significance
A smaller but important negative signal that reinforced caution with delayed treatment in unselected populations.
Alteplase in the 3-4.5 hour window vs placebo.
Clinical Significance
Central to expansion of the guideline treatment window to 4.5 hours in selected patients.
Perfusion-mismatch subgroup trial, 3-6 hour window.
Clinical Significance
Early imaging-selection concept trial that informed later precision-window studies, but without definitive efficacy signal.
Broad inclusion pragmatic trial up to 6 hours, including many older patients.
Clinical Significance
Important for real-world external validity: demonstrated that broad expansion without careful selection can dilute benefit and increase harm.
MRI mismatch-guided alteplase for unknown onset / wake-up stroke.
Clinical Significance
Landmark imaging-selection trial that changed management for wake-up stroke and strengthened individualized thrombolysis decisions.
Perfusion-imaging selected alteplase in 4.5-9 hour window.
Clinical Significance
Extended-window benefit appears possible when advanced imaging confirms salvageable tissue, but bleeding risk remains clinically meaningful.
| Author/Year | Design | Route | Intervention | Key Outcomes |
|---|---|---|---|---|
| NINDS, 1995 | PRCT n=624 |
IV | 0.9 mg/kg within 3h vs placebo | Mixed Part 1/2 signalFunctional gain in Part 2 |
| ECASS-1, 1995 | PRCT n=620 |
IV | 1.1 mg/kg within 6h vs placebo | Higher 30-day mortality |
| ECASS II, 1998 | PRCT n=800 |
IV | 0.9 mg/kg within 6h vs placebo | No functional benefitSICH increase |
| ATLANTIS-B, 1999 | PRCT n=613 |
IV | 3-5h window vs placebo | Stopped early; harm trend |
| ATLANTIS-A, 2000 | PRCT n=142 |
IV | 0-6h trial arm vs placebo | Higher 90-day mortality; SICH increase |
| ECASS III, 2008 | PRCT n=821 |
IV | 3-4.5h selected population | Improved mRSSICH higher |
| EPITHET, 2008 | PRCT n=101 |
IV | Perfusion mismatch subgroup, 3-6h | Primary endpoint NS; mortality trend higher |
| IST-3, 2012 | PRCT n=3,035 |
IV | Broad 0-6h real-world trial | No 180-day benefit; early harm signal |
| WAKE-UP, 2018 | PRCT n=503 |
IV | MRI mismatch-guided wake-up stroke treatment | Improved function with selected imaging profile |
| EXTEND, 2019 | PRCT n=225 |
IV | Perfusion-selected 4.5-9h window | Adjusted functional benefitSICH increase |
Bottom Line
Alteplase remains a time-sensitive option for selected acute ischemic stroke patients, but benefit is inseparable from hemorrhage risk and trial interpretation nuances.
For eligible patients, treatment speed matters. Earlier thrombolysis is associated with better functional recovery.
Independent re-analyses suggest baseline imbalances may overstate efficacy in some pivotal datasets; confidence should be calibrated accordingly.
Symptomatic intracranial hemorrhage risk is real across multiple trials and must be part of every bedside decision conversation.
Use protocolized eligibility checks, rapid imaging, and neurologic reassessment to maximize benefit while minimizing avoidable adverse outcomes.
- Powers WJ, Rabinstein AA, Ackerson T, et al. Guidelines for the early management of patients with acute ischemic stroke: 2019 update. Stroke. 2019;50(12):E344-E418.
- NINDS rt-PA Stroke Study Group. Tissue plasminogen activator for acute ischemic stroke. N Engl J Med. 1995;333:1581-1587.
- Hacke W, Kaste M, Fieschi C, et al. ECASS II. Lancet. 1998;352(9136):1245-1251.
- Sandercock P, Wardlaw JM, Lindley RI, et al. IST-3. Lancet. 2012;379(9834):2352-2363.
- Hacke W, Kaste M, Bluhmki E, et al. ECASS III. N Engl J Med. 2008;359(13):1317-1329.
- Thomalla G, Simonsen CZ, Boutitie F, et al. WAKE-UP. N Engl J Med. 2018;379(7):611-622.
- Hacke W, Kaste M, Fieschi C, et al. ECASS-1. JAMA. 1995;274(13):1017-1025.
- Clark WM, Wissman S, Albers GW, et al. ATLANTIS-B. JAMA. 1999;282(21):2019-2026.
- Clark WM, Albers GW, Madden KP, Hamilton S. ATLANTIS-A. Stroke. 2000;31:811-816.
- Davis SM, Rey G, Donnan A, et al. EPITHET. Lancet Neurol. 2008;7:299-309.
- Ma H, Campbell BCV, Parsons MW, et al. EXTEND. N Engl J Med. 2019;380(19):1795-1803.
- Marler JR, Tilley BC, Lu M, et al. Early stroke treatment and outcomes in NINDS. Neurology. 2000;55(11):1649-1655.
- Alper BS, Foster G, Thabane L, et al. ECASS III reanalysis adjusted for baseline imbalances. BMJ Evidence-Based Medicine. 2020;25:172-179.
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