A pilot study to assess the hemostatic function of pathogen-reduced platelets in patients with thrombocytopenia

Background: Platelet (PLT) support is critical to the care of patients with thrombocytopenia, but allogeneic transfusions carry risk. Pathogen reduction mitigates some transfusion risks, but effects on PLT function remain a concern. This clinical pilot study assessed the effect of pathogen reduction technology with riboflavin plus ultraviolet light using thrombelastography (TEG). Study Design and Methods: This prospective, randomized, crossover study compared Mirasol-treated (MIR) and standard reference (REF) PLT transfusions. PLT counts and TEG measurements were taken at pretransfusion and 1- and 24-hour-posttransfusion time points. The primary outcome measure was the pretransfusion to 1-hour-posttransfusion change in maximum amplitude (MA(1hr)). Secondary endpoints included MA among other time points, relative MA, and the PLT count-MA correlation. Results: Of 16 enrolled patients, one withdrew before study treatment and three did not require two transfusions, leaving 12 patients in the efficacy analyses (seven MIR-REF, five REF-MIR). MA(1hr) (mean +/- SD) was 10.60 +/- 6.47mm for MIR and 14.33 +/- 5.38mm for REF (p=0.20, n=10). MA(24hr) was 9.49 +/- 7.94 for MIR and 7.13 +/- 3.08 for REF (p=0.38, n=9); MA(24hr-1hr) was -1.11 +/- 2.95 for MIR and -7.20 +/- 4.81 for REF (p=0.016, n=8). MA values for MIR and REF correlated with the log of PLT count (r(MIR)=0.6901, r(REF)=0.7399). Conclusion: TEG is sensitive to changes in hemostatic function resulting from a single PLT transfusion. MIR and REF provided similar increments in hemostatic function in the immediate posttransfusion period and at 24 hours. A significant difference detected for MA(24hr-1hr) suggests different PLT clearance mechanisms. The relationship of these variables to clinically meaningful outcomes, for example, bleeding events or transfusion requirements, has yet to be determined.