A small Australian study found aspirin resistance correlated with an increase in severity and size of infarct in patients admitted to hospital with an acute stroke. The study was lead by Bernard Yan, MD, of Royal Melbourne Hospital in Parkville, Australia, and colleagues.
The use of aspirin before a stroke has been associated with less severe symptoms at admission and improved functional outcomes at discharge. And short-term aspirin therapy has been shown to significantly reduce the risks of death and dependency at 6 months following an acute ischemic stroke. Resistance to aspirin, however, may contribute to poor clinical outcomes in some patients. The presence of aspirin resistance was associated with a worse stroke according to both the NIHSS and ASPECTS.
Bernard Yan said, “Aspirin also reduces platelet microaggregates and platelet-derived vasoconstricting products,” they added. “This may ease ischemic injury by improving local blood flow. Aspirin-resistant patients may not experience the same therapeutic effect and, as a result, sustain a larger stroke.”
Alternatively, other neuroprotective or anti-inflammatory processes could be involved in the observed relationship, Yan and colleagues noted.
Note that both the NIH Stroke Scale (NIHSS) and the Alberta Stroke Program Early CT Score (ASPECTS) were used as assessments in this study.