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Updated: May 27, 2026
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Responsiveness to P2Y12 receptor inhibitors
1Division of Cardiology, Federico II University, Naples, Italy.
Purpose Of Review:
This review is aimed at describing the variability in response to P2Y12 inhibitor agents, and to focus on the main tests currently available to assess the responsiveness.
Recent Findings:
There is high interindividual response variability to clopidogrel. Some patients do not respond to the drug; this condition can be due to patient-related factors (poor compliance, genetic factors, cardiovascular risk profile) or to drug-related factors (reduced bioavailability or absorption, drug-drug interactions). In particular, mutations of the gene encoding for cytochrome CYP2C19, responsible for clopidogrel metabolism, are associated with an increased risk of cardiovascular events. Many tools for assessing platelet function are now available, but an appropriate test able to correlate platelet function to patient clinical outcome is still far from being recognized. There is also no standardized method to address their role in clinical practice. In addition, the safety and efficacy of alternative treatments for patients with 'clopidogrel resistance' has not been demonstrated yet. The recent findings from the Gauging Responsiveness with a VerifyNow Assay-Impact on Thrombosis and Safety (GRAVITAS) study showed that increasing the dose of clopidogrel in patients who are resistant does not decrease the incidence of cardiovascular events. Therefore, until the results of large-scale trials of personalized antiplatelet therapy are available, the routine use of platelet function measurements in the care of patients with cardiovascular disease cannot be recommended.
Summary:
Clopidogrel resistance is associated with higher incidence of cardiovascular events. Despite several available tools to test clopidogrel responsiveness, there is no uniform definition of 'non-responder' patients. The reduction of platelet reactivity in non-responder patients is not associated with reduced cardiovascular events. Current evidence suggests that higher antiplatelet regimens provide clinical benefits to the patient's risk profile rather than his/her 'platelet profile'.
Insights
Clopidogrel resistance, a variable response to this antiplatelet drug, is linked to increased cardiovascular events. Current platelet function tests lack standardization and do not reliably predict outcomes, making routine use not recommended.
Area of Science:
- Pharmacology
- Cardiovascular Medicine
- Clinical Trials
Background:
- P2Y12 inhibitors like clopidogrel are crucial in managing cardiovascular diseases.
- Interindividual variability in patient response to clopidogrel necessitates understanding non-responsiveness.
- Genetic factors, such as CYP2C19 mutations, significantly influence clopidogrel metabolism and efficacy.
Purpose of the Study:
- To review the variability in patient responses to P2Y12 inhibitor agents.
- To examine the diagnostic tools available for assessing P2Y12 inhibitor responsiveness.
- To discuss the clinical implications of clopidogrel resistance.
Main Methods:
- Literature review of studies on P2Y12 inhibitor response variability.
- Analysis of current platelet function tests for assessing drug responsiveness.
- Evaluation of clinical trial data, including the GRAVITAS study.
Main Results:
- High interindividual variability in clopidogrel response exists, influenced by patient and drug-related factors.
- Mutations in CYP2C19 are associated with increased cardiovascular risk in non-responders.
- Current platelet function tests lack correlation with clinical outcomes and standardized methods for clinical practice.
Conclusions:
- Clopidogrel resistance is associated with a higher incidence of cardiovascular events.
- No uniform definition of 'non-responder' exists, and reducing platelet reactivity does not guarantee reduced events.
- Personalized antiplatelet therapy based on risk profile, not solely platelet function, is suggested pending further large-scale trials.
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