Low on-clopidogrel ADP- and TRAP-6-induced platelet aggregation in patients with atrial fibrillation undergoing...

Area of Science:

• Cardiology
• Pharmacology
• Thrombosis

Background:

• High on-clopidogrel platelet reactivity (HPR) is linked to ischemic events post-percutaneous coronary intervention (PCI).
• Atrial fibrillation (AF) patients undergoing PCI often require oral anticoagulation (OAC), complicating antiplatelet therapy management.
• Assessing platelet reactivity in AF patients on OAC post-PCI is crucial for managing ischemic and bleeding risks.

Purpose of the Study:

• To investigate the association between HPR, assessed by multiple electrode aggregometry (MEA), and ischemic, thromboembolic, and bleeding risks in AF patients post-PCI.
• To determine the prevalence of HPR and low platelet reactivity (LPR) in this specific patient cohort.
• To evaluate the utility of ADP-induced aggregation in predicting clinical outcomes.

Main Methods:

• Prospective cohort study including 159 AF patients 1-3 days after PCI.
• Platelet aggregation analyzed using MEA, defining HPR as ADP-induced aggregation ≥ 46 U and LPR as ≤ 18 U.
• Primary outcome: composite of all-cause death, myocardial infarction, or stroke at 6 months. Secondary outcome: bleeding events.

Main Results:

• The majority of patients (93%) exhibited low overall platelet aggregability, with only 1% showing HPR and 79% demonstrating LPR.
• ADP-induced aggregation did not significantly correlate with the primary ischemic outcome (p=0.309).
• ADP-induced aggregation showed an inverse correlation with bleeding risk (r=-0.201, p=0.011), suggesting a potential role in bleeding risk assessment.

Conclusions:

• HPR is uncommon in AF patients undergoing PCI, and overall platelet aggregability is typically low.
• Current conventional cut-off values for HPR may not be appropriate for AF patients on OAC post-PCI.
• ADP-induced aggregation levels may serve as a valuable tool for identifying patients at higher risk of bleeding.