BACKGROUND: Cryopreservation extends platelet (PLT) shelf life from 5 to 7 days to 2 to 4 years. However, only 73 patients have been transfused cryopreserved PLTs in published randomized controlled trials (RCTs), making safety data insufficient for regulatory approval. STUDY DESIGN AND METHODS: The Cryopreserved vs. Liquid Platelet (CLIP) study was a double-blind, pilot, multicenter RCT involving high-risk cardiothoracic surgical patients in four Australian hospitals. The objective was to test, as the primary outcome, the feasibility and safety of the protocol. Patients were allocated to study group by permuted block randomization, with patients and clinicians blinded by use of an opaque shroud placed over each study PLT unit. Up to 3 units of cryopreserved or liquid-stored PLTs were administered per patient. No other aspect of patient care was affected.Adverse events were actively sought.
RESULTS:A total of 121 patients were randomized, of whom 23 received cryopreserved PLTs and 18 received liquid-stored PLTs.There were no differences in blood loss (median, 715 mL vs. 805 mL at 24 hr; difference between groups 90 mL [95% CI, -343.8 to 163.8 mL], p = 0.41), but the Bleeding Academic Research Consortium criterion for significant postoperative hemorrhage in cardiac surgery composite bleeding endpoint occurred in nearly twice as many patients in the liquidstored group (55.6% vs. 30.4%, p = 0.10). Red blood cell transfusion requirements were a median of 3 units in the cryopreserved group versus 4 units with liquid-stored PLTs (difference between groups, 1 unit [95% CI, -3.1 to 1.1 units]; p = 0.23). Patients in the cryopreserved group were more likely to be transfused fresh-frozen plasma (78.3% vs. 27.8%, p = 0.002) and received more study PLT units (median, 2 units vs. 1 unit; difference between groups, 1 unit [95% CI, -0.03 to 2.0 units]; p = 0.012).There were no between-group differences in potential harms including deep venous thrombosis, myocardial infarction, respiratory function, infection, and renal function. No patient had died at 28 days, and postoperative length of stay was similar in each group.
CONCLUSION:In this pilot RCT, compared to liquid-stored PLTs, cryopreserved PLTs were associated with no evidence of harm. A definitive study testing safety and hemostatic effectiveness is warranted.A fter donation, platelets (PLTs) are stored at 20 to 24 C with agitation to prolong circulating time after transfusion. This limits their shelf life to 5 to 7 days 1 but despite this, PLTs cause 84% of transfusiontransmitted bacterial infections. 2 Short shelf life also leads to high levels of wastage: one-fourth to one-third of units are discarded due to expiry. 3,4 To limit wastage, PLTs are only kept routinely in larger hospitals where use is high and predictable. Bleeding patients in smaller hospitals are more likely to be denied this potentially lifesaving treatment. ABBREVIATIONS: BARC = Bleeding Academic Research Consortium; DVT = deep venous thrombosis; ICU = intensive care unit; IQR = interquartile range; OR ...