Inclusion Criteria for Thrombolytics in Suspected Stroke
Intravenous tissue plasminogen activator (tPA) should be administered to eligible patients with acute ischemic stroke within 3 hours of symptom onset, with consideration for extended treatment up to 4.5 hours in carefully selected patients. 1
Primary Inclusion Criteria
Time Window
- Within 3 hours of symptom onset: Strongest evidence for benefit with Number Needed to Treat (NNT) of 8 1
- 3-4.5 hours after symptom onset: Less robust benefit (NNT of 14) but still recommended in selected patients 1, 2
Clinical Criteria
- Measurable deficit on NIH Stroke Scale 3
- Clearly defined time of symptom onset 3
- Baseline CT scan showing no evidence of hemorrhage 3
Imaging Criteria
- No evidence of intracranial hemorrhage on initial brain CT 3
- For patients treated within 3 hours: The presence of early infarct signs on CT (even if involving >1/3 of the middle cerebral artery territory) does not preclude treatment 4
- For patients in the 3-4.5 hour window: ASPECTS score of 6 or higher is preferred (indicating small-to-moderate ischemic core) 5
- If CT or MR perfusion is used, it should demonstrate a perfusion mismatch of at least 20% 5
Blood Pressure Requirements
- Systolic BP <185 mmHg and diastolic BP <110 mmHg before initiation of IV thrombolysis 6, 3
- BP must be maintained <180/105 mmHg for the first 24 hours after IV thrombolysis 6
Additional Considerations for 3-4.5 Hour Window
Patients in the 3-4.5 hour window must also meet these additional criteria 3:
- Age ≤80 years
- No severe stroke (NIHSS >25)
- No combination of previous stroke and diabetes mellitus
- No oral anticoagulant use (regardless of INR)
Exclusion Criteria
Time-Related Exclusions
Medical History Exclusions
- Another stroke or serious head injury within the preceding 3 months 3
- Major surgery within prior 14 days 3
- History of intracranial hemorrhage 3
- Gastrointestinal or genitourinary hemorrhage within previous 21 days 3
- Arterial puncture at a noncompressible site within previous 7 days 3
Clinical Exclusions
- Rapidly improving or minor symptoms 3
- Symptoms suggestive of subarachnoid hemorrhage 3
- Seizure at onset of stroke (although this is being reconsidered with newer imaging techniques) 3, 7
Laboratory Exclusions
- Use of anticoagulation with elevated values:
- Glucose level <50 mg/dL or >400 mg/dL 3
Implementation Considerations
System Requirements
- Rapid access to brain imaging and interpretation 4
- Protocols for drug administration and monitoring 3
- Ability to manage complications 3
- Target door-to-needle time of <60 minutes in 90% of treated patients 5
Post-Treatment Management
- Frequent neurological assessments 1
- Blood pressure monitoring every 15 minutes for 2 hours, then every 30 minutes for 6 hours 1
- No anticoagulants or antiplatelets for 24 hours after tPA administration 1
Common Pitfalls to Avoid
- Delaying treatment while waiting for laboratory results in otherwise eligible patients 1
- Inappropriate blood pressure management 1
- Failure to recognize stroke mimics 1
- Initiating anticoagulation too early (within 24 hours of IV tPA) 1
- Treating beyond recommended time windows, which significantly increases hemorrhage risk 1
The decision to administer thrombolytics should be made rapidly but carefully, weighing the potential benefits against the risks of treatment. The risk of symptomatic intracerebral hemorrhage is approximately 6% with an NNH of 17 1, but this is outweighed by the mortality and morbidity benefits in appropriately selected patients.