Absolute Contraindications for IV Thrombolysis in Acute Ischemic Stroke
Do not administer IV alteplase to patients with acute intracranial hemorrhage on CT, history of intracranial hemorrhage, subarachnoid hemorrhage, severe head trauma within 3 months, intracranial/intraspinal surgery within 3 months, active internal bleeding, or coagulopathy (platelets <100,000/mm³, INR >1.7, aPTT >40s, PT >15s). 1
Imaging-Based Contraindications
- Acute intracranial hemorrhage on CT is an absolute contraindication to IV alteplase 1
- Extensive regions of clear hypoattenuation (obvious hypodensity representing irreversible injury) on CT should preclude treatment, as these patients have poor prognosis despite alteplase 1
Hemorrhagic Risk Contraindications
Prior Intracranial Events
- History of any intracranial hemorrhage is potentially harmful and contraindicated 1
- Subarachnoid hemorrhage presentation is absolutely contraindicated 1
- Severe head trauma within 3 months is contraindicated, including posttraumatic infarction during acute in-hospital phase 1
Recent Procedures
- Intracranial or intraspinal surgery within 3 months is potentially harmful 1
- GI malignancy or GI bleeding within 21 days makes patients high-risk and alteplase potentially harmful 1
Coagulation Abnormalities
Laboratory Parameters
- Platelets <100,000/mm³ - treatment should not be administered or should be discontinued if discovered after initiation 1
- INR >1.7 - contraindicated unless patient has not recently used oral anticoagulants 1
- aPTT >40 seconds - contraindicated 1
- PT >15 seconds - contraindicated 1
Important caveat: In patients without history of thrombocytopenia or recent anticoagulant use, treatment can be initiated before laboratory results are available but must be discontinued if values exceed these thresholds 1
Anticoagulant Medications
- Treatment dose LMWH within 24 hours - should not be administered 1
- Direct thrombin inhibitors or factor Xa inhibitors - contraindicated unless laboratory tests (aPTT, INR, ecarin clotting time, thrombin time, or direct factor Xa activity assays) are normal OR patient has not received a dose for >48 hours with normal renal function 1
Concurrent Medication Contraindications
- Glycoprotein IIb/IIIa receptor inhibitors should not be administered concurrently with IV alteplase outside clinical trials 1
Cardiac and Vascular Contraindications
- Infective endocarditis - treatment should not be administered due to increased risk of intracranial hemorrhage 1
- Aortic arch dissection (known or suspected associated with stroke) is potentially harmful and should not be administered 1
Oncologic Contraindications
- Intra-axial intracranial neoplasm - treatment is potentially harmful 1
Temporal Contraindications
- Prior ischemic stroke within 3 months may be harmful 1
- Time last known well >4.5 hours (for standard treatment windows) - not recommended for unclear/unwitnessed onset or wake-up strokes beyond this timeframe 1
Common Pitfalls to Avoid
The 2018 AHA/ASA guidelines emphasize that many historical contraindications have been challenged by real-world evidence 2, 3. However, the absolute contraindications listed above remain firm based on hemorrhagic risk. The key distinction is between absolute contraindications (where harm clearly outweighs benefit) and relative contraindications (where careful risk-benefit assessment may allow treatment in select cases). When laboratory values are borderline or unavailable, err on the side of obtaining results before treatment unless the clinical scenario strongly favors immediate intervention 1.