Platelet reactivity after clopidogrel loading in patients with acute ischemic stroke

Area of Science:

• Neuroscience
• Pharmacology
• Cardiovascular Medicine

Background:

• Clopidogrel is a key antiplatelet agent used in acute ischemic stroke (AIS).
• The timing of sufficient antiplatelet effect after clopidogrel loading in AIS patients remains unclear.
• Platelet function testing (PFT) is used to assess antiplatelet drug response.

Purpose of the Study:

• To evaluate clopidogrel response in AIS patients using PFT.
• To compare clopidogrel response between AIS patients and those with other cerebrovascular diseases (CVD).
• To examine the prevalence and associated factors of abnormal clopidogrel response in AIS.

Main Methods:

• P2Y12 reaction unit (PRU) values were measured using VerifyNow at baseline and 6, 24, and 72 hours post-clopidogrel loading (300 mg).
• Comparison of PRU values between AIS patients and other CVD patients.
• Analysis of clopidogrel hypo-responder prevalence and associated factors, including CYP2C19 genotype.

Main Results:

• PRU values decreased over time in both AIS and other CVD groups.
• AIS patients exhibited significantly higher PRU values than other CVD patients at 6 and 24 hours post-loading.
• A higher prevalence of clopidogrel hypo-responders (PRU > 240 at 24h) was observed in AIS patients (79% vs. 33%).

Conclusions:

• Residual platelet reactivity 24 hours after clopidogrel loading is substantially higher in AIS patients.
• The majority of AIS patients are identified as hypo-responders by PFT.
• The interpretation of PFT results in AIS requires caution due to poor specificity for predicting clinical ischemic events.