Hemostatic efficacy of pathogen-inactivated- versus untreated- platelets: a randomized controlled trial
Pathogen inactivation of platelet concentrates reduces the risk of blood-borne infections. However, its effect on platelet function and hemostatic efficacy of transfusion is unclear. We conducted a randomized noninferiority trial comparing the efficacy of pathogen inactivated platelets using riboflavin and ultraviolet B illumination technology (intervention) compared to standard plasma-stored platelets (control) for the prevention of bleeding in patients with hematologic malignancies and thrombocytopenia. The primary outcome parameter was the proportion of transfusion treatment periods in which the patient had grade 2 or higher bleeding as defined by World Health Organization (WHO) criteria. Between November 2010 and April 2016, 469 unique patients were randomized to 567 transfusion treatment periods (283 in the control arm, 284 in the intervention arm). There was a 3% absolute difference in grade ≥ 2 bleeding in the intention-to-treat analysis: 51% of the transfusion treatment periods in the control arm and 54% in the intervention arm (95% CI -6 to 11, p-value for noninferiority 0.012). In the per-protocol analysis, however, difference in grade ≥ 2 bleeding was 8%: 44% in the control arm and 52% in the intervention arm (95% CI -2 to 18, p-value for noninferiority 0.19). Transfusion increment parameters were about 50% lower in the intervention arm. There was no difference in the proportion of patients developing HLA class I alloantibodies. In conclusion, the noninferiority criterion for pathogen inactivated platelets was met in the intention-to-treat analysis. This finding was not demonstrated in the per protocol analysis. (The Netherlands National Trial Registry number: NTR2106).
Effect of pre-incubation at 37 degrees C of platelet concentrates on the post-transfusion platelet adhesion capacity to collagen and fibrinogen
The effect of warming (37 degrees C) of stored platelet concentrates (PC) on the post-transfusion platelet function as measured by the adhesion capacity in a rectangular perfusion system under flow conditions was analyzed in 22 patients undergoing transfusion for stable thrombocytopenia. Nine patients received a PC stored at 22 degrees C and incubated at 37 degrees C for 1 h before transfusion, 10 patients received a non-warmed PC, 3 patients received both a pre-warmed and a non-warmed PC. In the PC the platelet adhesion capacity to collagen was higher in the pre-warmed PC than in the non-warmed PC (33 +/- 5.9% coverage vs. 22 +/- 4.7% coverage, respectively, in a selected group with the same platelet concentration). The adhesion capacity to collagen of the platelets in the patient's blood, measured 10 min after transfusion, had increased considerably in both patient groups and 4 h later the adhesion capacity in both patient groups was similar to that of the pre-warmed PC before transfusion. We conclude that though pre-warming of stored PC had a beneficial effect on the adhesion capacity to collagen of the platelets in the PC, the clinical significance is questionable because already 10 min after transfusion the adhesion capacity to collagen of stored non-warmed platelets had improved to the level of the pre-warmed platelets and 4 h after transfusion this improvement was still present.