Normalization of platelet reactivity in clopidogrel-treated subjects

Area of Science:

• Cardiovascular Medicine
• Hematology
• Pharmacology

Background:

• Aspirin (ASA) and clopidogrel are standard treatments for acute coronary syndrome (ACS).
• Persistent antiplatelet effects from these drugs can complicate surgical procedures.
• Effective strategies are needed to manage antiplatelet activity before surgery.

Purpose of the Study:

• To investigate the possibility of normalizing platelet reactivity after aspirin (ASA) and clopidogrel treatment.
• To quantify the amount of platelet concentrate required to reverse the antiplatelet effects.

Main Methods:

• Healthy subjects received ASA + clopidogrel loading doses (300 or 600 mg) followed by daily maintenance doses.
• Platelet reactivity was assessed using light transmittance aggregometry (LTA) and flow cytometry.
• Ex vivo transfusion of pooled volunteer platelets (V-PRP) into subject PRP (S-PRP) was used to normalize platelet function.

Main Results:

• At 4 and 72 hours post-treatment, 40% or 50% V-PRP was needed to overcome platelet disaggregation after ADP challenge, depending on the clopidogrel dose.
• An additional 10% V-PRP fully normalized aggregation, with recovery being linear.
• Similar V-PRP amounts normalized platelet function against other agonists like arachidonic acid (AA), collagen, and TRAP.

Conclusions:

• Pre-operative transfusion of 10-12.5 platelet concentrate units may reverse clopidogrel-induced platelet disaggregation, facilitating hemostasis.
• An additional 2.5 units fully normalized platelet function.
• Further in vivo clinical studies are warranted to confirm these findings in patients undergoing surgery.