Comparison of factors affecting platelet reactivity in various platelet function tests

Area of Science:

• Cardiovascular Medicine
• Pharmacology
• Clinical Laboratory Science

Background:

• Platelet reactivity is crucial for patients on clopidogrel therapy, with various factors influencing its efficacy.
• Dual antiplatelet therapy (DAPT) is standard after coronary intervention, but individual responses vary.

Purpose of the Study:

• To investigate whether clinical and laboratory variables affecting platelet reactivity during DAPT are assay-dependent.
• To compare influencing factors for high platelet reactivity (HPR) across different platelet function assays.

Main Methods:

• Enrolled 904 patients receiving DAPT post-coronary intervention.
• Measured platelet reactivity using VerifyNow P2Y12, multiple electrode aggregometry (MEA) ADP, and light transmittance aggregometry (LTA) ADP assays.
• Analyzed correlations between assay results and clinical/laboratory variables (hematocrit, platelet count, gender, smoking).

Main Results:

• VerifyNow results correlated inversely with hematocrit; MEA and LTA showed weaker or no correlation.
• MEA results correlated positively with platelet count; LTA showed a weak positive correlation.
• Independent predictors for HPR varied by assay: VerifyNow (gender, hematocrit), MEA (smoking, platelet count), and LTA (platelet count).

Conclusions:

• The incidence of high platelet reactivity (HPR) and its associated influencing variables are significantly dependent on the platelet function assay employed.
• Clinical decisions based on platelet reactivity testing should consider the specific assay's limitations and influencing factors.