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Updated: Mar 16, 2026
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Changes in response to clopidogrel therapy in patients after percutaneous coronary interventions as assessed by
Insights
Clopidogrel therapy response can change over time, but different platelet function tests show poor agreement, limiting clinical use. These findings highlight the need for standardized methods to assess clopidogrel response in patients post-percutaneous coronary intervention.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Diagnostics
Background:
- Clopidogrel is a key antiplatelet medication used after percutaneous coronary intervention (PCI).
- Responder status to clopidogrel therapy can fluctuate over time, impacting treatment efficacy.
- Accurate monitoring of clopidogrel response is crucial for patient outcomes.
Purpose of the Study:
- To investigate temporal changes in clopidogrel responder status using four distinct platelet function tests.
- To compare the reliability and agreement of light transmission aggregometry (LTA), multiple electrode aggregometry (MEA), vasodilator-stimulated phosphoprotein (VASP) phosphorylation, and INNOVANCE® PFA P2Y assays (PFA).
- To determine the most reliable method for assessing clopidogrel response in patients post-PCI.
Main Methods:
- Study included 35 patients post-PCI on dual antiplatelet therapy (aspirin and clopidogrel).
- Platelet function was assessed using LTA, MEA, VASP, and PFA at three time points: early post-PCI (4±2 days), 6 weeks, and 12 weeks.
- A control group of 50 healthy volunteers was included for comparison.
Main Results:
- Clopidogrel responder status changed over time in 14-37% of patients, depending on the test used.
- VASP assays showed the highest rate of change (37%), followed by LTA and PFA (20%), and MEA (14%).
- Agreement between the four tests was moderate to poor (Cohen's κ < 0.46), with significant discrepancies, especially involving VASP.
Conclusions:
- Temporal changes in clopidogrel response are detectable across all tested platelet function assays.
- Significant discrepancies and only moderate agreement among the tests limit their interchangeable use in clinical practice.
- Further research and standardization are needed for reliable assessment of clopidogrel response in patients post-PCI.
Abstract:
INTRODUCTION Recently, the responder status to clopidogrel therapy has been observed to change over time. OBJECTIVES The aim of the study was to investigate changes in the responder status to clopidogrel therapy over time with the use of 4 platelet function tests (light transmission aggregometry [LTA], multiple electrode aggregometry [MEA], vasodilator-stimulated phosphoprotein (VASP) phosphorylation, and INNOVANCE® PFA P2Y assays [PFA]) in patients after percutaneous coronary intervention (PCI). We also compared the results of these tests to determine the most reliable method. PATIENTS AND METHODS The study included 35 patients after PCI, receiving acetylsalicylic acid (75 mg/d) and clopidogrel (75 mg/d). The control group included 50 healthy volunteers. Platelet function was measured at 3 different time points (4 ±2 days after PCI, and then after 6 and 12 weeks). RESULTS The responder status to clopidogrel changed in 5 patients (14%) as shown by MEA; in 7 patients (20%), by LTA and PFA; and in 13 patients (37%), by VASP. The Cohen's κ coefficient showed a moderate or poor agreement between the tests. The strongest agreement was between MEA and PFA (80%; κ = 0.46, P = 0.003), PFA and LTA (82%; κ = 0.41, P = 0.004), and MEA and LTA (80%; κ = 0.36, P = 0.008). The κ coefficient for all comparisons with VASP was less than 0.30. CONCLUSIONS Changes in the responder status over time are present for all platelet function tests, but a large discrepancy between the tests does not allow a careful assessment of this phenomenon. The tests showed only moderate agreement (in relation to one another and to time points), which significantly limits their interchangeable use in clinical practice.
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