Doctors often prescribe low-dose aspirin to people at high risk of stroke because the drug helps prevent blood clots. But for about 28% of stoke patients in a new study, aspirin didn’t keep blood from clotting. And their strokes were worse than strokes suffered by aspirin-uses who weren’t resistant to the drug.
“Aspirin resistance is an important predictor of severe stoke and large stroke size in patients taking aspirin before having a stroke,” said lead researcher Dr. Mi Sun Oh, of the department of neurology at Hallym University College of Medicine in Seoul.
What causes aspirin resistance isn’t known. Other studies have found that 5-45% of patients have this problem, but doctors do not routinely test for it.
“In patients at high risk for stroke with aspirin resistance, different anti-clotting drugs – such as Plavix – can be considered as alternatives to prevent another stroke or decrease stroke severity,” Oh said.
The findings of the study were released February 23, ahead of its official presentation in April at the annual meeting of the American Academy of Neurology in Washington, D.C. Data and conclusions presented at meetings are usually considered preliminary until published in a peer-reviewed medical journal.
For the study, Oh and colleagues studied 310 patients who had been taking aspirin for at least seven days before they suffered an ischemic stroke. Aspirin resistance was checked within 24 hours of hospital admission.
The researchers found that nearly 28% of the patients were resistant to aspirin. Their strokes ranged from 3 to 11 on a stroke severity score, compared with scores of 1 to 6 among aspirin responders.
