MedWire News: The benefits of thrombolysis outweigh the risks even among patients taking antiplatelet drugs at stroke onset, indicate the results of a large observational study.
But the researchers warn of an increased risk for symptomatic intracerebral hemorrhage (ICH) among the subgroup of patients taking combined aspirin and clopidogrel.
This suggests that “caution may need to be exercised in use of thrombolysis in this group of patients if they are at significantly increased risk of symptomatic ICH because of other factors,” say Niaz Ahmed (Karolinska University Hospital, Stockholm, Sweden) and colleagues in the journal Stroke.
The researchers base their conclusions on results from 11,865 patients treated according to European regulations and recorded in the Safe Implementation of Treatments in Stroke International Stroke Thrombolysis Register (SITS-ISTR).
Of these, 31.9% had been taking antiplatelet drugs at stroke onset: 25.4% aspirin; 2.0% clopidogrel; 1.5% aspirin and dipyridamole; 1.3% aspirin and clopidogrel; and 1.7% other antiplatelet agents. These patients tended to be older and to have more vascular risk factors than those not taking antiplatelet drugs.
Just 1.1% of patients not on antiplatelet drugs suffered symptomatic ICH, defined as at least a 4-point deterioration on the National Institutes of Health Stroke Scale (NIHSS) plus an ICH type 2 within 24 hours of the clinical change.
Among patients taking antiplatelet agents, symptomatic ICH rates ranged from 1.7% to 2.5%, but among those taking aspirin plus clopidogrel 4.1% suffered symptomatic ICH.
With a broader definition of symptomatic ICH (4-point NIHSS deterioration plus any ICH), it occurred in 4.1% of patients not on antiplatelet agents, 13.9% of those of aspirin plus clopidogrel, and 4.2% to 6.2% of those on other antiplatelet agents.
After adjusting for confounders, aspirin plus clopidogrel use was associated only with symptomatic ICH by the broader definition, raising the risk 2.11 fold. And despite this, patients taking aspirin plus clopidogrel were no more likely than other patients to die and no less likely to achieve an excellent outcome or functional independence (modified Rankin Scale 0–1 or 0– 2, respectively).
The researchers recommend: “Before decision for thrombolysis, additional factors possibly contributing to symptomatic ICH, such as elevated blood pressure, advanced age, and stroke severity, should be considered carefully in this subset of patients.”
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