Related Experiment Video
Updated: Sep 5, 2025
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
High-on-Aspirin Platelet Reactivity Differs Between Recurrent Ischemic Stroke Associated With Extracranial and
Kyung Chul Noh1,2, Hye-Yeon Choi1, Ho Geol Woo3
1Department of Neurology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
Insights
Recurrent ischemic stroke is more common with extracranial atherosclerosis (ECAS) and high on-aspirin platelet reactivity (HAPR). Artery-to-artery embolism is linked to HAPR in both ICAS and ECAS.
Area of Science:
- Neurology
- Cardiology
- Vascular Medicine
Background:
- Recurrent ischemic stroke despite antiplatelet therapy remains a clinical challenge.
- Mechanisms of recurrence vary, involving intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS).
- High on-aspirin platelet reactivity (HAPR) may differentially impact stroke recurrence based on atherosclerosis location.
Purpose of the Study:
- To investigate the association between HAPR and recurrent ischemic stroke.
- To compare HAPR prevalence and influencing factors in patients with ICAS versus ECAS.
- To explore the role of stroke mechanism, specifically artery-to-artery embolism, in HAPR.
Main Methods:
- Consecutive enrollment of patients with recurrent ischemic stroke on aspirin therapy.
- Classification of stroke as ICAS or ECAS based on culprit stenosis location.
- Definition of HAPR as aspirin reaction units (ARU) >550 IU; comparison of HAPR and associated factors between ICAS and ECAS groups.
Main Results:
- Of 190 patients, 18.3% exhibited HAPR.
- Higher ARU values and HAPR prevalence were observed in the ECAS group compared to the ICAS group (p=0.008).
- Male sex and ECAS were independently associated with HAPR (OR=5.760, p<0.001); artery-to-artery embolism showed the highest ARU values and was linked to HAPR in both groups.
Conclusions:
- Recurrent stroke due to ECAS is more strongly associated with HAPR and inadequate antiplatelet inhibition than ICAS.
- Artery-to-artery embolism is a significant factor associated with HAPR in recurrent ischemic stroke, regardless of ICAS or ECAS.
Background And Purpose:
Ischemic stroke recurs despite the use of antiplatelet agents. Various mechanisms are involved in recurrence due to intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS). High-on-aspirin platelet reactivity (HAPR) may differ between recurrent stroke due to ICAS and ECAS.
Methods:
Patients with recurrent ischemic stroke as a result of large-artery atherosclerosis despite taking aspirin were enrolled consecutively. Ischemic stroke was classified as stroke due to ICAS or ECAS according to the location of the culprit stenosis. An aspirin reaction units (ARU) value of >550 IU was defined as HAPR. HAPR and its associated factors were compared between the two groups and also considering the mechanism of stroke.
Results:
Among the 190 patients with recurrent stroke (111 with ICAS and 79 with ECAS), 36 (18.3%) showed HAPR. The ARU value was higher in the ECAS than the ICAS group (492±83 vs. 465±78, mean±standard deviation; p=0.028), as was the proportion of patients with HAPR (27.8% vs. 12.6%, p=0.008). Being male and having stroke due to ECAS (reference=stroke due to ICAS: odds ratio=5.760; 95% confidence interval=2.154-15.403; p<0.001) was independently associated with HAPR. The ARU value differed according to the stroke mechanism, and was highest in those with artery-to-artery embolism. Artery-to-artery embolism was independently associated with HAPR in both the ICAS and ECAS groups.
Conclusions:
Recurrent stroke due to ECAS was more strongly associated with HAPR and insufficient antiplatelet inhibition than was that due to ICAS. Artery-to-artery embolism was associated with HAPR in recurrent ischemic stroke as a result of ICAS or ECAS.
Related Concept Videos
01:27Atherosclerosis II: Clinical Manifestations and Diagnostic Tests
01:30Peripheral Artery Disease I: Introduction