Related Experiment Videos
Platelet function in acute myocardial infarction treated with direct angioplasty
11. Medizinische Klinik, Technischen Universität München, Germany.
Insights
Platelet activation temporarily decreases after acute myocardial infarction (AMI) treatment with percutaneous transluminal coronary angioplasty (PTCA). However, platelet activation increases post-PTCA, highlighting the need for new antiplatelet therapies in AMI patients.
Area of Science:
- Cardiology
- Hematology
- Thrombosis Research
Background:
- Platelets are crucial in acute myocardial infarction (AMI) thrombotic processes.
- Platelet function post-percutaneous transluminal coronary angioplasty (PTCA) in AMI remains unevaluated.
Purpose of the Study:
- To evaluate platelet function in patients with AMI undergoing direct PTCA.
- To assess changes in platelet activation markers and behavior after coronary artery recanalization.
Main Methods:
- Flow cytometry to measure fibrinogen receptor function and P-selectin expression.
- Evaluation of platelet-derived microparticle generation.
- Assessing plasma effects on normal platelet function and adhesion to endothelial cells.
Main Results:
- Platelet activation markers (fibrinogen receptor, P-selectin) decreased 8 hours post-PTCA in AMI patients.
- A decrease in platelet count and increase in microparticle generation were observed.
- Plasma from AMI patients enhanced normal platelet aggregation and adhesion to endothelial cells.
Conclusions:
- Circulating platelets show transient deactivation followed by increased activation post-PTCA in AMI.
- Hyperactive platelets may be sequestered, leading to temporary decreases in circulating activation.
- Novel antiplatelet strategies are essential for managing AMI patients treated with PTCA.
Background:
In acute myocardial infarction (AMI), platelets play a key role in thrombotic processes that limit the patency of the recanalized, infarct-related coronary artery and contribute to reperfusion injury. Platelet function in the course of AMI treated by direct percutaneous transluminal coronary angioplasty (PTCA) has not been evaluated.
Methods And Results:
In 15 patients with anterior AMI, peripheral venous blood samples were obtained before and 4, 8, 24, and 48 hours after recanalization of the occluded artery by PTCA. Fifteen patients who had stable coronary heart disease and were undergoing elective balloon angioplasty served as control subjects. Fibrinogen receptor function and surface expression of P-selectin on platelets were determined by flow cytometry. In addition, we evaluated generation of platelet-derived microparticles and the effect of systemic plasma from patients with AMI on normal platelet function and on platelet adhesion to human endothelial cells in culture. We found fibrinogen receptor activity and P-selectin expression on circulating platelets 8 hours after direct PTCA are decreased (P < .01). This coincided with a decrease in peripheral platelet count (P < .05) and an increase in generation of microparticles (P < .002). Twenty-four to 48 hours after PTCA, fibrinogen receptor activity and P-selectin expression increased again. Systemic plasma obtained before and after direct PTCA sensitized normal platelets to hyperaggregate in vitro (P < .001) and stimulated platelet adhesion to endothelial cells in culture (P < .01). None of the changes found in AMI were detectable in the control group.
Conclusions:
After transient apparent deactivation of circulating platelet, probably caused by sequestration of hyperactive platelets, the level of platelet activation increases in patients with AMI treated by direct PTCA. These findings underscore the need for novel antiplatelet strategies in AMI.