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Shear-induced platelet aggregation in normal subjects and stroke patients
K Konstantopoulos1, J C Grotta, C Sills
1Cox Laboratory for Biomedical Engineering, Rice University, Houston, TX 77251-1892, USA.
Thrombosis and Haemostasis
|November 1, 1995
Summary
Elevated shear stress in arteries significantly activates platelets, especially in atherosclerotic stroke patients. This enhanced platelet aggregation (SIPA) is a chronic risk factor for stroke, not a transient consequence of ischemia.
Area of Science:
- Cardiovascular Science
- Hematology
- Neurology
Background:
- Arterial stenosis increases shear stress, potentially triggering platelet aggregation and thrombosis.
- Platelet activation and aggregation are critical in the development of thrombotic events, including ischemic stroke.
Purpose of the Study:
- To investigate shear-induced platelet aggregation (SIPA) in ischemic stroke patients compared to normal subjects.
- To determine if platelet activation and aggregation are chronic factors in stroke patients, particularly those with atherosclerosis.
Main Methods:
- Utilized a viscometric-flow cytometric technique to measure SIPA.
- Studied 23 ischemic stroke patients (15 atherosclerotic, 8 lacunar) and normal subjects.
- Assessed platelet activation using an anti-P-selectin antibody and quantified neutrophil-platelet aggregates.
Main Results:
- High shear stress strongly activates and aggregates platelets, with a more pronounced response in non-lacunar stroke patients with atherosclerotic disease.
- SIPA was not affected by the time of blood draw, indicating chronic platelet abnormalities.
- Atherosclerotic stroke patients showed significantly higher platelet activation and neutrophil-platelet aggregates, even one month post-stroke.
Conclusions:
- Enhanced platelet activation and elevated SIPA are not transient consequences of ischemia but are chronic risk factors for stroke.
- Platelet reactivity, particularly SIPA, may play a significant role in thrombotic mechanisms underlying stroke.
- The developed methodology can aid in characterizing platelet reactivity and understanding thrombotic processes.