Background This pilot trial focused on feasibility and safety to provide preliminary data to evaluate the hemostatic potential of cold-stored platelets (2° to 6°C) compared with standard room temperature–stored platelets (20° to 24°C) in adult patients undergoing complex cardiothoracic surgery. This study aimed to assess feasibility and to provide information for future pivotal trials. Methods A single center two-stage exploratory pilot study was performed on adult patients undergoing elective or semiurgent complex cardiothoracic surgery. In stage I, a two-armed randomized trial, platelets stored up to 7 days in the cold were compared with those stored at room temperature. In the subsequent single-arm stage II, cold storage time was extended to 8 to 14 days. The primary outcome was clinical effect measured by chest drain output. Secondary outcomes were platelet function measured by multiple electrode impedance aggregometry, total blood usage, immediate and long-term (28 days) adverse events, length of stay in intensive care, and mortality. Results In stage I, the median chest drain output was 720 ml (quartiles 485 to 1,170, n = 25) in patients transfused with room temperature–stored platelets and 645 ml (quartiles 460 to 800, n = 25) in patients transfused with cold-stored platelets. No significant difference was observed. The difference in medians between the room temperature– and cold-stored up to 7 days arm was 75 ml (95% CI, −220, 425). In stage II, the median chest drain output was 690 ml (500 to 1,880, n = 15). The difference in medians between the room temperature arm and the nonconcurrent cold-stored 8 to 14 days arm was 30 ml (95% CI, −1,040, 355). Platelet aggregation in vitro increased after transfusion in both the room temperature– and cold-stored platelet study arms. Total blood usage, number of adverse events, length of stay in intensive care, and mortality were comparable among patients receiving cold-stored and room temperature–stored platelets. Conclusions This pilot trial supports the feasibility of platelets stored cold for up to 14 days and provides critical guidance for future pivotal trials in high-risk cardiothoracic bleeding patients. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

BACKGROUND: Cold storage of platelets may extend shelf life compared to room temperature storage. This study aimed to investigate in vitro platelet quality and function in cold-stored and delayed-cold-stored nonagitated apheresis platelets in platelet additive solution during storage for 21 days.STUDY DESIGN AND METHODS: Ten double apheresis platelet concentrates in 37% plasma/63% PAS-IIIM were split into two groups; nonagitated 2 to 6 C storage (CSPs) and delayed cold storage (DCSPs) with 7 days agitated storage at 20-24 C followed by nonagitated cold storage for 14 additional days. Platelet count, metabolism, viscoelastic properties, and aggregation ability were measured on Days 1, 7, 14, and 21.ABBREVIATIONS: CSPs = cold-stored platelets; DCSPs = delayedcold-stored platelets; LME = linear mixed-effect; MA = maximum clot strength; MaxA = maximum aggregation; MPV = mean platelet volume; PAS = platelet additive solution; PCs = platelet concentrates; R = time to first clot formation; TEG = thromboelastography; TRAP-6 = thrombin receptor activating peptide 6.From the * Values shown as mean (95% confidence interval), n = 10 in each group. † For each outcome, we fitted a LME using time, group and their interaction as predictors. In the time domain, we applied simple contrast (change from baseline day 1; CSP group). CSP = cold-stored platelet; DCSP = delayed-cold-stored platelet; LME = linear mixed effect model; MPV = mean platelet count; PLT = platelet count.

BACKGROUND: Some jurisdictions require leukoreduction of cellular blood components. The only whole blood collection set with a platelet-saving filter uses citrate-phosphate-dextrose (CPD) as storage solution. Substituting CPD with citrate-phosphatedextrose-adenine (CPDA-1) increases shelf life from 21 to 35 days. This would simplify prehospital and rural resupply and reduce wastage. We investigated in vitro quality and hemostatic properties of CPDA-1 whole blood leukoreduced with a platelet-saving filter.STUDY DESIGN AND METHODS: CPDA-1 whole blood was leukoreduced using a platelet-saving filter and stored 35 days. EDQM requirements, hematology, metabolic parameters, thromboelastography, light transmission aggregometry, fibrinogen, factor VIII, and interleukin-6 were measured on Days 0, 1, 14, 21, and 35 and compared to non-leukoreduced blood.From the

Diagnostic study, level IV.