Aspirin resistance are associated with long-term recurrent stroke events after ischaemic stroke

To investigate the prevalent of aspirin resistance (AR) in stroke and its association with recurrent stroke in 214 patients with ischemic stroke who were receiving aspirin before the stroke onset.

Two hundreds and fourteen acute stroke patients who previously received aspirin therapy (100mg/day for ≥7days) were enrolled. Whole blood samples were collected for platelet aggregation testing. The result is expressed in aspirin reaction units (ARU). A cutoff of 550 ARU was used to determine the presence of AR. A follow-up period of 1year was performed to record stroke recurrence events.

In this study, the median age was 68 years (IQR, 60-77 years), and 118 (55.1%) were men. A total of 43 of 214 enrolled patients (20.1%) were AR. ARU levels were significantly higher in patients with recurrence than those without (514[IQR: 466-592] vs. 454[IQR: 411-499]; P <0.001). The stroke recurrence distribution across the ARU quartiles ranged between 7.41% (first quartile) to 40.74% (fourth quartile). In multivariate analyses, the 3th and 4th quartile of ARU was significantly associated with stroke recurrence during the observation period compared to the 1st quartile group, and the adjusted risk increased by 215% (OR=3.15 [95% CI 1.96-4.33], P=0.007) and 322% (4.22[2.56-7.16], P<0.001). In multivariate logistic regression analysis, AR was associated with a higher risk of stroke recurrence, and the adjusted risk increased by 365% (OR=4.65; 95% CI=2.99-8.16; P<0.001).

In conclusion, AR is not uncommon in Chinese stroke patients who receive anti-platelet medications. Patients with AR may have a greater risk of suffering stroke recurrence events.