PB1054 - Evaluation of platelet function in rare or undiagnosed bleeding disorders

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

PA

Paula Acuña Butta

Bsc
La Paz University Hospital
Madrid, Madrid, Spain

Co-Author(s)

EM

Elena Monzón Manzano

Research Associate
La Paz University Hospital
Madrid, Madrid, Spain
Elena García Arias-Salgado, PhD

Senior researcher
La Paz University Hospital
Madrid, Madrid, Spain
EG

Eduardo García, MD

Department of Hematology
La Paz University Hospital
Madrid, Madrid, Spain
María Teresa Alvarez-Román, MD, PhD

Head of the Thrombosis and Haemostasis Unit
La Paz University Hospital, Madrid, Spain
Madrid, Madrid, Spain
MM

Mónica Martín Salces

Specialist in Hematology
La Paz University Hospital
Madrid, Madrid, Spain
MR

Maria Isabel Rivas Pollmar

Specialist in Hematology
La Paz University Hospital
Madrid, Madrid, Spain
AD

Abel Dos Santos Ortas

Specialist in Hematology
La Paz University Hospital
Madrid, Madrid, Spain
EG

Elena García Astudillo

Nurse
Hospital Universitario La Paz-IdiPaz
Madrid, Madrid, Spain
Víctor Jiménez Yuste, MD PhD

Head of Hematology
La Paz University Hospital
Madrid, Madrid, Spain
NB

Nora V V. Butta Coll

Head of Hemostasis laboratory
La Paz University Hospital
Madrid, Madrid, Spain

Background: Qualitative and/or quantitative platelet defects promote bleeding and its identification requires a careful clinical evaluation and a rational use of diagnostic laboratory assays.

Aims: To study platelet function by different methods in patients with hemorrhagic symptoms who are suspected of thrombopathy to compare results obtained with each system and validate usefulness of methods employed.

Methods: We included 72 patients with bleeding suspected of thrombopathy, which in some cases was confirmed by genetic study (Table 1). Patients with coagulation disorders were excluded.
We used the following methods to test platelet function:
• Light aggregometry in platelet-rich plasma (PRP) using ADP, collagen, epinephrine and arachidonic acid as stimulating agonists.
• Flow cytometry in PRP using TRAP and ADP to induce platelet activation, and PAC1 monoclonal antibody (mAb) to recognize activated fibrinogen receptor, and anti P-selectin and anti-CD63 mAbs to test, respectively, release from alpha and dense granules.
• PFA-100® in whole citrated blood with collagen +ADP and collagen+Epinephrine cartridges.
• Total Thrombus-formation Analysis System (T-TAS® 01, Zarcos, Japan) with T-TAS® PL- chip (capillaries covered with collagen / under flow) in blood samples drawn in BAPA, a potent synthetic anticoagulant which inhibits Factor Xa and thrombin.

Results: Some bleeding due to platelet dysfunction was diagnosed by any of the methods used, but others can only be detected with some of the techniques tested (Table 2). This difference in the sensitivity of the methods may be due to the different experimental conditions used in each of them: type of sample used, platelets’ activators, and flow vs static conditions. Forty % of undiagnosed bleedings did not seem to be related to platelet dysfunction.

Conclusion(s): All methods are complementary and their sensitivity depends on the pathway evaluated by the technique used and the mechanism involved in platelet dysfunction.

Funding: Zacros, FUJIMORI KOGYO CO., LTD.