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Updated: Mar 27, 2026
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Factors influencing platelet reactivity in patients undergoing coronary artery bypass surgery
David J Schneider1, Sreedivya Chava
1Department of Medicine, Cardiology Unit, Cardiovascular Research Institute, University of Vermont, Burlington, Vermont, USA.
Insights
Following coronary artery bypass graft surgery, young platelets are more reactive, especially after clopidogrel treatment. Ticagrelor
Area of Science:
- Cardiovascular Surgery
- Hematology
- Pharmacology
Background:
- Coronary artery bypass graft (CABG) surgery leads to significant platelet turnover.
- Young, RNA-containing platelets exhibit distinct reactivity patterns.
- Assessing platelet function post-CABG is crucial for understanding thrombotic risk.
Purpose of the Study:
- To evaluate platelet reactivity one day after CABG in patients pre-treated with clopidogrel or ticagrelor.
- To investigate the impact of young (RNA-containing) platelets on post-CABG platelet function.
Main Methods:
- Patients (n=18) with acute coronary syndrome undergoing urgent CABG were analyzed.
- Pre-surgical treatment included aspirin plus clopidogrel (n=13) or ticagrelor (n=5).
- Platelet RNA content (thiazole orange) and platelet function (flow cytometry) were assessed one day post-CABG.
Main Results:
- Young platelets comprised an average of 24% of circulating platelets and showed higher activation.
- Enhanced reactivity of young platelets was significant in clopidogrel-treated patients (P<0.001).
- A trend towards increased young platelet reactivity was observed in ticagrelor-treated patients, though not statistically significant.
Conclusions:
- Young platelets are inherently more reactive, an effect amplified by clopidogrel's irreversible P2Y12 inhibition.
- Ticagrelor's reversible P2Y12 binding may offer advantages in high platelet turnover settings like post-CABG.
- Understanding differential platelet reactivity post-CABG is vital for optimizing antiplatelet therapy.
Objective:
Because coronary artery bypass graft (CABG) surgery is associated with a high turnover of platelets, assessment of platelet function should enable assessment of the effect of young (RNA-containing) platelets on platelet reactivity. This study was designed to assess platelet reactivity 1 day after CABG in patients treated previously with clopidogrel or ticagrelor.
Methods:
Patients (n=18) with acute coronary syndrome who required urgent CABG and had been treated for up to 2 days before surgery with aspirin plus clopidogrel (n=13) or aspirin plus ticagrelor (n=5) were enrolled. Care was not altered by participation, which entailed review of medical records and taking one sample of blood 1 day after surgery. The percentage of RNA-containing platelets was quantified using thiazole orange, and platelet function was assessed by flow cytometry.
Results:
Young platelets constituted, on average, 24% of platelets (range 4-54%) and were more likely to be activated in the absence or presence of an agonist (P<0.001). Differences between RNA-containing (young) and non-RNA-containing platelets were evident in patients treated previously with clopidogrel (P<0.001), whereas a nonsignificant trend was apparent in patients treated previously with ticagrelor. A high but variable prevalence of young platelets was seen 1 day after CABG.
Conclusion:
Young platelets were more reactive and, consistent with the irreversible binding of clopidogrel to P2Y12, this effect was more pronounced after treatment with clopidogrel. The reversible binding of ticagrelor to the platelet P2Y12 receptor may be advantageous in patients with a high platelet turnover.
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