Impact of transfusion on platelet aggregation and biomarkers in myocardial infarction patients with anemia: an ancillary study of the randomized REALITY trial

Abstract

Abstract Importance Higher rates of thrombotic events have been reported in patients with myocardial infarction (MI) requiring blood transfusion. The impact of transfusion strategies on biomarkers of thrombosis and inflammation is still unknown. Objective Compare the impact of a liberal vs a restrictive transfusion strategy in anemic MI patients on P2Y12 mediated platelet reactivity and biomarkers of thrombosis and inflammation. Design and Setting: Prespecified ancillary study of the multicentric randomized REALITY trial, performed in 6 French centers between February 2018 and September 2019 (Figure). Patients randomized to a liberal (hemoglobin ≤10g/dL) or a restrictive (hemoglobin ≤8g/dL) transfusion strategy had platelet reactivity measured at baseline and after randomization. Participants: One hundred anemic acute MI patients from the REALITY trial (666 randomized patients). Measurements: Measurements of platelet reactivity included a centralized blinded VASP-PRI assay and PRU measured locally using encrypted VerifyNow assay. Biomarkers of thrombosis (P-selectin, PAI-1, vWF) and inflammation (TNF-α) were also measured. The primary endpoint was the change in the VASP-PRI (difference from baseline and post randomization) between the two randomized groups. Results Among 100 patients included (n=50 in each group), the most frequent P2Y12 inhibitors used was clopidogrel (48%) while 16% of the patients did not receive any P2Y12 inhibitors. Transfused patients received on average 2.4±1.6 units of packed red blood cells. We found no differences between groups in change in P2Y12-mediated platelet aggregation before and after randomization, measured either by the VASP PRI (difference 4.3%; 95% CI (-5.4% to 14.1%)) or by the PRU (difference 23.5; 95% CI (-20.8 to 67.8)). Similar results were found in transfused patients (n=71) regardless of the randomized group, VASP PRI (difference 1.6%; 95% CI (-6.7% to 10.0%)) or PRU (difference -17.6; 95% CI (-41.0 to 5.7)). We did not find an impact of transfusion strategy or transfusion itself in the levels of P-selectin, PAI-1, vWF and TNF-α. Conclusion and Relevance A liberal or a restrictive transfusion strategy does not impact platelet reactivity and biomarkers in MI patients with anemia, supporting the lack of clinically relevant difference in thrombotic risk between both strategies.