New evidence for cold-stored platelets up to 21 Days for active surgical bleeding control – The CHIPS trial 

27 October 2026

Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) often require platelet transfusions to manage bleeding. The short shelf life of standard room-temperature platelets (RTP) restricts availability and increases risk of product wastage.   

The Chilled Platelet Study (CHIPS) was a phase 3, randomised, partially blinded, storage duration-ranging trial. It sought to determine the maximum cold-storage duration, up to 21 days, for which cold-stored platelets (CSPs) are noninferior or superior in haemostatic efficacy to RTPs when transfused in actively bleeding paediatric and adult cardiac surgery patients with CPB.  

The primary outcome was a haemostatic efficacy score ranging from 1 to 5, where higher values reflected greater bleeding. The noninferiority margin was 1 point. The secondary outcome was 24-hour chest tube output. Several prespecified exploratory outcomes were also measured.  

 Between December 2021 and March 2025, 1,000 patients (CSPs n=660 and RTPs n=340) underwent platelet transfusion across 25 sites in the US and 2 in Australia. Demographic data and comorbidities were similar amongst the treatment groups with the majority of patients male (67.8%). A total of 989 patients were included in the primary analysis (CSPs n=650 and RTPs n=339).   

The results revealed that CSPs, stored for all durations up to and including 21 days, were noninferior to RTPs for the primary outcome, with a probability of greater than 99.9%. Pooled analysis across storage durations showed similar primary outcome scores for CSPs and RTPs, with a mean difference from RTPs of 0.09 (95% CrI, −0.06 to 0.23).   

For the primary outcome, no storage duration of CSPs was statistically superior to RTPs. With respect to the secondary outcome of 24-hour total chest tube output (mL/kg), when comparing the study groups, no significant difference was found. Similarly, increasing the storage age of CSPs to 21 days did not appear to impact 24-hour chest tube output. No significant differences were observed in the exploratory safety outcomes, with the exception of increased reexploration rates in the CSP group. Limitations of the study include the lack of standardised indications for platelet transfusion and use of both CSPs and RTPs in a small portion of patients.   

The findings from this trial demonstrated that for patients undergoing cardiac surgery, CSPs stored up to 21 days are noninferior to RTPs for the control of active surgical bleeding. The authors note that use of CSPs may allow for increased platelet availability (by reducing wastage and shortages) and platelet inventory at locations where RTPs cannot be maintained due to their shelf life.  

The accompanying editorial highlights logistical issues and complexities that make a platelet transfusion ‘a small miracle’. It also explores important practical and scientific questions, including the need for further trials (for prophylactic indications and in other therapeutic areas).   

 

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