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Time course of platelet alpha granule release in acute myocardial infarction treated with streptokinase
N J Frandsen1, K Winther, F Pedersen
1Mineral metabolic research group, Hvidovre Hospital, University of Copenhagen, Denmark.
Insights
Platelet alpha granule release, indicated by beta thromboglobulin and platelet factor 4, significantly increases within 12 hours of acute myocardial infarction onset. Aspirin does not inhibit this early release in patients treated with streptokinase.
Area of Science:
- Cardiology
- Hematology
- Pharmacology
Background:
- Acute myocardial infarction (AMI) involves complex platelet activation.
- Platelet alpha granules store key proteins involved in hemostasis and inflammation.
- Understanding the timing of granule release is crucial for therapeutic interventions.
Purpose of the Study:
- To investigate the time course of platelet alpha granule release in AMI patients receiving streptokinase.
- To assess the impact of aspirin on this release mechanism.
Main Methods:
- Prospective study conducted in a coronary care unit.
- Patients with AMI (n=9) treated with streptokinase and aspirin, and a control group (n=9) with chest pain treated with aspirin only.
- Serial measurements of plasma beta thromboglobulin and platelet factor 4 post-chest pain onset.
Main Results:
- Median peak plasma beta thromboglobulin and platelet factor 4 were significantly higher in the AMI group compared to controls (P < 0.01).
- Elevated levels were observed within 12 hours of chest pain onset, with no significant difference after 12 hours.
- Aspirin treatment did not prevent alpha granule release.
Conclusions:
- Platelet alpha granule content is released within the initial 12 hours following chest pain onset in AMI patients treated with streptokinase.
- Aspirin appears to be ineffective in abolishing this early alpha granule release.
Objective:
To determine the time course of platelet alpha granule release in patients with acute myocardial infarction treated with streptokinase.
Design:
A prospective study.
Setting:
Coronary care unit.
Patients:
Nine with myocardial infarction treated with both streptokinase and aspirin, and nine with acute chest pain but without myocardial infarction, who were treated with aspirin only.
Methods:
All patients received 250 mg aspirin on admission and 150 mg once daily thereafter. All patients who fulfilled the indications for streptokinase received 1.5 megaunits, in a single infusion. After the initial medication, serial measurements of plasma beta thromboglobulin and plasma platelet factor 4 were performed at fixed intervals after the onset of chest pain. The primary endpoint sought was the peak value of beta thromboglobulin and platelet factor 4 in each individual.
Results:
The median peak plasma beta thromboglobulin in the infarction group was substantially higher than in those without infarction, at 37 (range 12 to 210) v 15 (9 to 36) mg/litre, P < 0.01. The corresponding values for plasma platelet factor 4 were 4.6 (2.4 to 60.0) v 2.2 (< 2 to 8.5) mg/litre, P < 0.01. Increased values were seen only within the first 12 h after onset of chest pain, and after 12 h there was no difference between the patients with myocardial infarction and those without. Aspirin treatment did not abolish alpha granule release.
Conclusions:
In patients with acute myocardial infarction treated with streptokinase the content of the alpha granules is released within the first 12 h after the onset of chest pain. Aspirin apparently does not abolish this release.