Temporal Variability of Platelet Reactivity in Patients Treated with Clopidogrel or Ticagrelor

Area of Science:

• Cardiology
• Pharmacology
• Clinical Trials

Background:

• Antiplatelet therapy is crucial for acute coronary syndrome (ACS) patients post-percutaneous coronary intervention (PCI).
• The antiplatelet response to P2Y12 inhibitors, like clopidogrel and ticagrelor, is linked to clinical outcomes.
• Understanding temporal variability in platelet reactivity is essential for optimizing antiplatelet treatment strategies.

Purpose of the Study:

• To evaluate and compare the variability of platelet reactivity over time in ACS patients treated with clopidogrel versus ticagrelor.
• To assess the incidence of high on-treatment platelet reactivity (HPR) and changes in responder status with both agents.

Main Methods:

• A single-center cohort study analyzed ACS patients undergoing PCI.
• Platelet reactivity was measured using multiple electrode platelet aggregometry at baseline, 48 hours, 1 month, and 6 months post-PCI.
• High on-treatment platelet reactivity (HPR) was defined as ≥47 U.

Main Results:

• Platelet reactivity significantly increased over time in the clopidogrel group (p=0.018) but remained stable in the ticagrelor group (p=0.392).
• A change in platelet reactivity >20 U occurred in 67.1% of clopidogrel users versus 34.4% of ticagrelor users (p<0.001).
• Responder status shifted in 43% of clopidogrel patients compared to 13% of ticagrelor patients between 48 hours and 6 months (p<0.001).

Conclusions:

• Ticagrelor demonstrated less temporal variability in platelet reactivity and HPR compared to clopidogrel.
• A significant proportion of patients experienced variability in platelet reactivity over time, irrespective of the P2Y12 inhibitor used.
• These findings underscore the dynamic nature of antiplatelet response and the need for vigilant monitoring.