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Regional and Systemic Platelet Function Is Altered by Myocardial Ischemia-Reperfusion
1University of Maryland Medical Center, Division of Cardiology, Department of Medicine, Baltimore, MD.
Journal of Thrombosis and Thrombolysis
|January 1, 1995
Summary
Platelet function changes during myocardial ischemia-reperfusion. Regional platelet aggregability increases during ischemia, while both regional and systemic platelet aggregability rise during reperfusion, potentially impacting coronary artery reocclusion.
Area of Science:
- Cardiovascular Physiology
- Hematology
- Ischemia-Reperfusion Injury
Background:
- Myocardial stunning (prolonged contractile dysfunction) follows ischemia-reperfusion.
- Ischemia-reperfusion may impair coronary endothelial function.
- Platelet function is partly regulated by the endothelium, suggesting potential changes during ischemia-reperfusion.
Purpose of the Study:
- To investigate the impact of brief myocardial ischemia and subsequent reperfusion on regional and systemic platelet function.
Main Methods:
- Open-chest swine model with 15-minute left anterior descending coronary artery (LAD) occlusion followed by 120 minutes of reperfusion.
- Simultaneous measurement of platelet aggregability (response to ADP) in femoral (systemic) and great cardiac (regional) venous blood.
- Assessment at baseline, during occlusion, and at 40 and 90 minutes post-reperfusion.
Main Results:
- Regional platelet aggregability significantly increased during LAD occlusion (126% of baseline).
- Systemic platelet aggregability decreased at 40 minutes of reperfusion (86% of baseline).
- Both systemic and regional platelet aggregability increased significantly at 90 minutes of reperfusion (127% and 156% of baseline, respectively).
Conclusions:
- Platelet function is dynamic during ischemia-reperfusion, with increased regional aggregability during ischemia.
- Both systemic and regional platelet aggregability increase during reperfusion.
- Mechanisms may involve endothelial dysfunction or release of pro-aggregatory mediators, with implications for post-ischemia coronary artery reocclusion.