Can a Patient Stay on Aspirin After Negative CT Head and CTA Head/Neck Following Stroke Workup?
Yes, the patient should be started on aspirin immediately if not already taking it, or continued on aspirin if already on it, following a negative CT head that excludes intracranial hemorrhage. 1
Immediate Management After Negative Imaging
All acute stroke patients not already on an antiplatelet agent and not receiving tPA therapy should be given at least 160 mg of aspirin immediately as a one-time loading dose after brain imaging has excluded intracranial hemorrhage. 1 This recommendation is based on Level A evidence showing that acute-phase aspirin therapy reduces the risk of early recurrent ischemic stroke. 1
Key Timing Considerations
- If the patient received tPA: Aspirin should be delayed until after the 24-hour post-thrombolysis scan has excluded intracranial hemorrhage. 1
- If no tPA was given: Aspirin should be started immediately after the negative CT scan and after dysphagia screening has been performed and passed. 1
Long-Term Aspirin Therapy
Aspirin (81 to 325 mg daily) should then be continued indefinitely or until an alternative antithrombotic regimen is started. 1 Long-term aspirin therapy reduces the risk of ischemic stroke, myocardial infarction, and vascular death. 1
Special Circumstances
If the patient was already on aspirin prior to the ischemic stroke or TIA: Clopidogrel may be considered as an alternative, as this represents aspirin "failure." 1 If rapid action is required, a loading dose of 300 mg of clopidogrel could be considered, followed by a maintenance dose of 75 mg once daily. 1
Evidence from a meta-analysis of 8,723 patients demonstrates that among those who experience an ischemic stroke while on aspirin monotherapy, the addition of or a switch to another antiplatelet agent is associated with reduced risks of major adverse cardiovascular events (hazard ratio 0.68) and recurrent stroke (hazard ratio 0.70), especially when initiated in the first days after the index event. 2
Administration Routes for Dysphagia
In dysphagic patients, aspirin may be given by:
Evidence Base
The recommendation for immediate aspirin use is supported by combined analysis of 40,000 randomized patients from the Chinese Acute Stroke Trial (CAST) and International Stroke Trial (IST), which showed a highly significant reduction of 7 per 1,000 in recurrent ischemic stroke and a net decrease of 9 per 1,000 in the overall risk of further stroke or death in hospital. 3 This benefit was consistent across all patient subgroups, including the elderly, those with atrial fibrillation, different blood pressure levels, and various stroke subtypes. 3
Critical Pitfall to Avoid
Do not withhold aspirin based solely on the absence of a definitive stroke etiology on CTA. The negative CTA head and neck simply indicates no large vessel occlusion or significant stenosis requiring immediate intervention, but does not change the indication for aspirin therapy in acute ischemic stroke. 1 The primary goal is secondary stroke prevention, which aspirin accomplishes regardless of the specific vascular anatomy visualized on imaging.