Abstract
Transfusion Service - Transfusion Practices
Cold-stored platelets (CSPs) were recently approved to be stored for up to 14 days and transfused to bleeding patients. The available clinical data on CSPs are very limited. In this pilot trial, we tested the feasibility of conducting a randomized controlled trial in cardiac surgery patients using extended-stored CSPs in 100% plasma.
Study
Design/Methods:
We conducted a single center, randomized, controlled, double-blind, pilot study in adult patients undergoing elective redo or complex cardiothoracic surgery. Patients were allocated to receive either standard of care, room temperature-stored platelets (RTPs) for up to 7 days, or CSPs stored between 10 and 14 days based on a week-based block randomization scheme. Up to three units of shroud-blinded study platelets were transfused from the start of surgery to up to 24h after. The primary outcome was defined as recruitment and accrual feasibility. Numerous efficacy and safety endpoints were assessed. All platelet units were screened for aggregates using a standard RTP release criteria score as recommended by AABB standards.
Results/Findings:
In total, 15 patients received RTPs, and 9 received CSPs (including three patients who received both). Because of the continuous occurrence of aggregates in CSPs and the resulting excess of subjects receiving RTPs, the final 9 transfused participants were allocated to receive CSPs. Results reported here are from a post hoc “as-treated” analysis. No significant difference in the number of RBCs, plasma units, or platelet units was observed between the study groups. The total amount of chest tube drainage was not significantly different between the groups. The thromboelastography testing showed no significant differences at baseline, 30min, and 24h after transfusion. However, it revealed significantly smaller maximum amplitudes 4h after transfusion with CSPs compared to RTPs (p=0.02). In contrast, recipients of CSPs formed significantly larger aggregates 1h after transfusion (p=0.04) and generated significantly higher contractile forces under in vitro shear 1h and 4h after transfusion (p=0.003 and p=0.03). Only one death within 28 days occurred in the RTP transfusion group, while none occurred in the CSPs group. The average platelet age at transfusion for CSPs was 11.2 days versus 3.4 days for RTP. Overall, 179 CSP units were ordered for transfusion in this trial. We found that most CSPs (58%) were not usable for transfusion using conventional RTP release criteria, mainly due to the presence of aggregates.
Conclusions:
Due to the abundance of aggregates in CSPs, this pilot trial does not support the feasibility of CSPs in 100% plasma using RTP release criteria. Our study highlights the need for discussion on whether revised release criteria for CSPs are needed and safe.