The aim of this study is to analyze the effect of the storage time of platelet concentrates on the occurrence of bleeding events during prophylactic platelet transfusions in patients with hematological malignancies.

Since 2017, the preparation processes and shelf life of platelet concentrates (PCs) have been changed to increase transfusion safety and optimise transfusion processes. These changes have led to an increase in the total number of PCs transfused, a decrease in the number of platelets per PC and an increase in the number of platelets transfused per patient. Previous studies have shown that longer storage of platelets contributes to less in vivo recirculation of transfused platelets. Studies of haemostatic efficacy have generally not reported a significant effect. However, the haemostatic efficacy of PC stored for more or less than 5 days has not been evaluated. The ECLAT multicentre prognostic cohort study will prospectively and comparatively evaluate the haemorrhagic event in haematology patients with severe thrombocytopenia transfused according to the duration of PC storage.

Inclusion Criteria:

• Patients with haematological malignancies or bone marrow aplasia with severe thrombocytopenia due to bone marrow failure related to the disease or treatments received
• Severe thrombocytopenia requiring transfusion
• Patient able to self-assess bleeding events
• Non-opposition of the subject to participate in the study
• Registered with the French social security system or benefiting from such a system.

Exclusion Criteria:

• Acute promyelocytic leukaemia
• Curative dosage of anticoagulants
• Treatment with antiplatelet agents
• Patient with proven thrombocytopenia of immunological origin, or disseminated intravascular coagulation
• Patients with a clinically significant haemorrhagic event (WHO grade 2) in the 48 hours prior to transfusion
• Indication for deplasmatised, cryopreserved and reduced-volume PCs
• Patient refusing transfusion of labile blood products
• Pregnant women or breast-feeding mothers
• Adults subject to a legal protection measure or unable to express their consent
• Persons deprived of their liberty by a judicial or administrative decision; persons under compulsory psychiatric care; persons admitted to a health or social care institution for purposes other than research
• Subject in the exclusion period of another study

Patients treated for haematological malignancy with severe thrombocytopenia associated with bone marrow failure and requiring platelet transfusion