Aspirin-resistant people are believed to be at higher risks of getting severe strokes.

Doctors and healthcare professionals normally prescribe a small dose of aspirin to patients who are at elevated risk of getting a stroke as aspirin helps in preventing blood clots. However, a South Korean study suggests that people who are resistant to aspirin get severe strokes in comparison to those who are not resistant to the anti-clotting drug.

"Aspirin resistance is an important predictor of severe stroke and large stroke size in patients taking aspirin before having a stroke," says Dr. Mi Sun Oh at Hallym University College of Medicine in Seoul, who is also the lead researcher of the study.

The researchers suggest that even though many people are aspirin-resistant; it is not known what causes such resistance. Previous studies have discovered that 5 to 45 percent of patients may be aspirin-resistant but it is not a common process for doctors and healthcare professionals to test such a resistance.

Researchers suggest that people suffering with aspirin resistance need an alternate type of medicine to prevent blood clotting, which may cause stroke. Aspirin-resistant patients should be given alternative drugs such as clopidogrel (Plavix), an anti-clotting drug, for treatment of stroke or decreasing a stroke's severity.

The study included more than 300 patients who were taking aspirin for at least seven days before experiencing an ischemic stroke. The resistance to aspirin was examined within 24 hours of the patient being hospitalized.

The study found that 28 percent of the patients were aspirin-resistant. The strokes in these patients were between 3 and 11 on the stroke severity score, which is higher in comparison to non-aspirin resistant patients who scored between 1 and 6.

The researchers also found that the brain area affected due to a stroke in aspirin-resistant patients was more when compared to non-aspirin resistant patients.

The researchers suggest that the study is important as it points the importance of testing aspirin resistance in patients. The latest study should also encourage doctors to test patients for aspirin-resistance, which will allow prescribing an alternate anti-clotting drug or a higher dose of aspirin.

The U.S. Centers for Disease Control and Prevention (CDC) reveals that about 130,000 Americans die of strokes each year, which is 1 of every 20 deaths.