Usefulness of platelet function tests to predict bleeding with antithrombotic medications

Area of Science:

• Cardiovascular Medicine
• Pharmacology
• Hematology

Background:

• Platelet inhibition balances antithrombotic effects with bleeding risk.
• Increased use of antiplatelet agents and novel oral anticoagulants raises bleeding concerns.
• Current methods for assessing bleeding risk are insufficient for individual patient management.

Purpose of the Study:

• To evaluate the limitations of current platelet function tests (PFTs) in predicting bleeding risk.
• To explore novel methods for assessing bleeding risk in patients on antithrombotic therapy.
• To identify techniques that better reflect the physiological impact of antithrombotic medications.

Main Methods:

• Review of current PFTs like VerifyNow and vasodilator-stimulated phosphoprotein (VASP) assay.
• Discussion of limitations of PFTs using anticoagulated blood.
• Introduction of endogenous thrombin potential (ETP) assays using native blood, such as calibrated automated thrombogram (CAT) and global thrombosis test (GTT).

Main Results:

• PFTs identify low on-treatment platelet reactivity but do not reliably predict major bleeding.
• Many individuals with low platelet reactivity do not experience bleeding events.
• ETP assays performed on native blood show promise for physiologically assessing medication effects on thrombin and bleeding risk.

Conclusions:

• Current PFTs are inadequate for individual bleeding risk assessment in patients on antithrombotic therapy.
• Techniques measuring endogenous thrombin potential in native blood offer a more promising approach.
• Further research into ETP assays may allow for tailored antithrombotic therapy to optimize the risk:benefit ratio.