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Platelet function tests in thrombotic cerebrovascular disorders
Insights
Platelet function tests reveal distinct patterns in cerebrovascular disease (CVD). Thrombotic CVD shows enhanced platelet aggregation and activators, unlike cardiogenic embolism, suggesting different disease mechanisms.
Area of Science:
- Neuroscience
- Hematology
- Cardiology
Background:
- Obstructive cerebrovascular disease (CVD) encompasses various conditions, including transient ischemic attacks (TIA), reversible ischemic neurological deficits (RIND), and cerebral infarcts.
- Cardiogenic embolism, often associated with rheumatic valvular heart disease (RVHD), represents a distinct cause of stroke.
- Understanding platelet function is crucial for differentiating CVD subtypes and their pathogenesis.
Purpose of the Study:
- To investigate and compare platelet function in patients with different forms of obstructive cerebrovascular disease (CVD).
- To evaluate the role of platelet aggregation, von Willebrand factor (VIII:vWF), platelet aggregation enhancing factor (PAEF), and megathrombocytes in CVD pathogenesis.
- To assess the effect of aspirin therapy on platelet function in these patients.
Main Methods:
- Platelet function tests including ADP and ristocetin-induced aggregation, spontaneous aggregation, VIII:vWF, PAEF, and percentage of large platelets (megathrombocytes) were performed.
- Serial testing was conducted in acute stroke patients.
- The impact of aspirin therapy (600 mg p.o.) on platelet parameters was examined.
Main Results:
- Patients with TIA, RIND, and cerebral infarct exhibited enhanced platelet aggregation (induced and spontaneous), elevated plasma VIII:vWF and PAEF, and increased megathrombocytes.
- Patients with cardiogenic embolism showed normal results except for an increased percentage of megathrombocytes compared to non-embolic RVHD patients.
- Platelet aggregation and megathrombocyte percentage increased slowly post-stroke and normalized with aspirin treatment.
Conclusions:
- A systemic increase in hyperaggregable platelets and plasma activators is associated with thrombotic CVD, potentially contributing to its pathogenesis.
- Local hemodynamic factors may play a more significant role in the thrombogenesis of cardiogenic embolism.
- Platelet function abnormalities in thrombotic CVD can be modulated by aspirin therapy.
Abstract:
A variety of platelet function tests were performed in patients with four forms of obstructive cerebrovascular disease (CVD); transient ischemic attacks (TIA), reversible ischemic neurological deficit (RIND), cerebral infarct, and cerebral embolism of cardiac source in rheumatic valvular heart disease (RVHD). Platelet studies included platelet aggregation induced by ADP and ristocetin, spontaneous platelet aggregation, von Willebrand factor (VIII:vWF), platelet aggregation enhancing factor (PAEF), and percentage of large platelets (megathrombocytes). Serial testing was carried out in acute stroke patients. The effect of aspirin therapy was also evaluated. A clear difference in results was observed between patients with cardiogenic embolism and those with other forms of CVD. In patients with TIA, RIND, and cerebral infarct, platelet aggregation, both induced and spontaneous, was enhanced along with elevation of plasma VIII:vWF and PAEF, and increased percentage of megathrombocytes. In patients with cardiogenic embolism, however, these studies were negative except for percent megathrombocytes. This value was increased in the embolic patients with RVHD in comparison with non-embolic patients with RVHD. Increase in platelet aggregation to ADP and percent megathrombocytes developed slowly over a week following stroke. Induced and spontaneous platelet aggregation, and percent megathrombocytes could be normalized with 600 mg aspirin p.o. These studies suggest that a systemic increase of hyperaggregable platelets and of plasma activators of platelet function exists in thrombotic CVD and may be related to its pathogenesis, while local hemodynamic factors may be more important in the thrombogenesis of cardiogenic embolism.