PB0866 - Unidentified pre-analytical factors influence measures of platelet reactivity in the Framingham Heart Study

Monday, July 11, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Co-Author(s)

Melissa V. Chan, PhD

Post-Doctoral Fellow
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, MA, USA.
Framingham, Massachusetts, United States
MC

Ming-Huei Chen

Staff Scientist
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, Massachusetts, USA
Framingham, Massachusetts, United States
FT

Florian Thibord, PhD

Post-Doctoral researcher
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, MA, USA.
Framingham, Massachusetts, United States
BN

Bongani B. Nkambule, PhD

Post-Doctoral Fellow
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, MA, USA.
Framingham, Massachusetts, United States
AL

Amber Lachapelle

Research Associate
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, MA, USA.
Framingham, Massachusetts, United States
CW

Catherine Wallace de Melendez

Research Associate
NHLBI
Framingham, Massachusetts, United States
ZS

Zoe E. Schneider

NIH IRTA Post-Baccalaureate Fellow
NHLBI
Framingham, Massachusetts, United States
Jason A. Cunha, B.A.

Postbaccalaureate IRTA Fellow
National Heart Lung and Blood Institute, Division of Intramural Research, Bethesda, MD, USA
Framingham, Massachusetts, United States
Robin E. Pashek

NIH IRTA Post-Baccalaureate Fellow
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, MA, USA.
Framingham, Massachusetts, United States
JG

Joseph Grech

NIH IRTA Post-Baccalaureate Fellow
NHLBI
Framingham, Massachusetts, United States
PA

Paul C. Armstrong, PhD

Assistant Professor
Blizard Institute, Queen Mary University of London
London, England, United Kingdom
TW

Timothy D. Warner

Professor
Blizard Institute, Queen Mary University of London
London, England, United Kingdom

Presenting Author(s)

Andrew D. D. Johnson, PhD

Professor
Population Sciences Branch, Division of Intramural Research, National Heart, Lung and Blood Institute, Framingham, MA, USA.
Framingham, Massachusetts, United States

Background: The assessment of platelet reactivity is key in diagnosing bleeding disorders and the evaluation of anti-platelet drug efficacy. However, there is a prevailing “one-size fits all” approach in the interpretation of measures of platelet reactivity, with arbitrary cut-offs based on healthy volunteer responses.

Aims: Using the large platelet reactivity dataset obtained in the Framingham Heart Study (FHS), we assessed whether any pre-analytical or technical factors contribute to these platelet reactivity measures.

Methods: Blood and platelet-rich plasma were obtained from the FHS (N=3,429) and details such as time and date of draw, anti-platelet medication use, any deviations from a standard blood draw were noted. Platelet reactivity was measured in response to a range of agonists in five platelet assays: light transmission aggregometry (LTA), Optimul aggregometry, Multiplate aggregometry, Total Thrombus-formation Analysis System (T-TAS) and flow cytometry. Lipemic and hemolyzed samples were excluded from analysis, and linear mixed-effect models were used to determine factors which modulated platelet reactivity traits.

Results: As expected, aspirin strongly attenuated platelet responses, most notably to arachidonic acid (final aggregation LTA, β=-1.724, P< 9.48e-657). P2Y12 antagonists attenuated ADP responses in all assays. Furthermore, sex and age robustly modulated agonist responses (Figure). Fasting status did not alter platelet reactivity measures. Interestingly, draw times later in the day and longer time from draw to test attenuated platelet responses. Finally, agonist batch, phlebotomist, and assay technician (more so for “hands on” assays such as flow cytometry) had a moderate-large effect on platelet reactivity.

Conclusion(s): This study highlights the importance of considering pre-analytical variables and technical factors in the interpretation of platelet reactivity measures. Caution must be exercised in the use of standard ranges, unless stratified by age and sex. In large studies agonist batch and technician variation should be reduced and steps should be taken to standardize time of blood draw.