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Citrate-phosphate-dextrose (CPD) is the most common anticoagulant for blood product storage in the United States. It was developed to prolong shelf life, though there is little research regarding its impact on function following transfusion. We used flow cytometry (FC), thromboelastography (TEG), and a clot contraction assay called the zFlex platform to measure platelet activation and global clot formation in blood samples anticoagulated with either CPD or in a standard blue top citrate (BTC) tube. Samples were obtained through venipuncture of the antecubital fossa from healthy donors who had not recently taken antiplatelet medication. Samples for FC analysis were spun to obtain platelet-rich plasma, while TEG and zFlex utilized recalcified whole blood. Mean fluorescence intensity for CD62p (P-selectin, marker of platelet activation) in baseline samples was equal, while mean fluorescence intensity in samples activated with thrombin receptor activating peptide was higher in CPD than BTC (65,814 ± 4445 versus 52,483 ± 5435, P = 0.007). TEG results demonstrated similar maximum amplitude for CPD (62.7 ± 1.8 mm versus 61 ± 1 mm) (P = 0.33), though reaction time and kinetics time were significantly longer in CPD versus BTC. CPD R-time: 7.9 ± 0.4 min versus BTC: 3.8 ± 0.4 (P < 0.001). CPD K-time: 2.2 ± 0.2 min versus BTC: 1.6 ± 0.1 min (P < 0.001). Clot contraction strength was not different between the two groups on zFlex: CPD 4353 ± 6 = 517 μN versus BTC 4901 ± 390 μN (P = 0.39). Our findings suggest that CPD does not affect platelet function (minimal difference on FC and no difference in ultimate clot strength, which is ∼80% due to platelet function) but may alter clot dynamics by attenuating thrombin generation. [ABSTRACT FROM AUTHOR]

Background: Demand for low‐titer Group O whole blood (LTOWB) is increasing for trauma. The whole blood (WB) platelet‐sparing (WB‐SP) filter enables leukoreduction (LR) while retaining platelet quantity and function; however, in the United States WB must be filtered and placed in the cold within 8 h of collection. A longer processing window would facilitate improved logistics and supply of LR‐WB to meet the growing medical need. This study evaluated the impact of increasing filtration timing from <8 h to <12 h on the quality of LR‐WB. Study Design and Methods: Thirty WB units were collected from healthy donors. Control units were filtered within 8 h and test units within 12 h of collection. WB was tested throughout 21 days of storage. Hemolysis, WBC content, component recovery, and 25 additional markers of WB quality were tested including hematologic and metabolic markers, RBC morphology, aggregometry, thromboelastography, and p‐selectin. Results: There were 0 failures for residual WBC content, hemolysis, or pH, and no differences in component recovery between arms. Few differences in metabolic parameters were observed, but the small effect size suggests these are not clinically significant. Trends throughout storage were similar and filtration timing did not impact hematological parameters, platelet activation and aggregation, or hemostatic capacity. Conclusion: Our studies showed that extending filtration timing from 8 to 12 h from the collection does not significantly impact the quality of LR‐WB. Characterization of the platelets demonstrated that storage lesions were not exacerbated. Extending the time from collection to filtration will improve LTOWB inventory in the United States. [ABSTRACT FROM AUTHOR]

Background: Demand for low‐titer Group O whole blood (LTOWB) is increasing for trauma. The whole blood (WB) platelet‐sparing (WB‐SP) filter enables leukoreduction (LR) while retaining platelet quantity and function; however, in the United States WB must be filtered and placed in the cold within 8 h of collection. A longer processing window would facilitate improved logistics and supply of LR‐WB to meet the growing medical need. This study evaluated the impact of increasing filtration timing from <8 h to <12 h on the quality of LR‐WB. Study Design and Methods: Thirty WB units were collected from healthy donors. Control units were filtered within 8 h and test units within 12 h of collection. WB was tested throughout 21 days of storage. Hemolysis, WBC content, component recovery, and 25 additional markers of WB quality were tested including hematologic and metabolic markers, RBC morphology, aggregometry, thromboelastography, and p‐selectin. Results: There were 0 failures for residual WBC content, hemolysis, or pH, and no differences in component recovery between arms. Few differences in metabolic parameters were observed, but the small effect size suggests these are not clinically significant. Trends throughout storage were similar and filtration timing did not impact hematological parameters, platelet activation and aggregation, or hemostatic capacity. Conclusion: Our studies showed that extending filtration timing from 8 to 12 h from the collection does not significantly impact the quality of LR‐WB. Characterization of the platelets demonstrated that storage lesions were not exacerbated. Extending the time from collection to filtration will improve LTOWB inventory in the United States. [ABSTRACT FROM AUTHOR]

Introduction: Hematologic effects of North American rattlesnake envenomation can include fibrinogenolysis and thrombocytopenia, depending on species, geography, and other variables. During treatment, these effects are routinely monitored through assessment of fibrinogen concentrations and platelet counts. However, these tests provide no information about fibrinolysis or platelet dysfunction, both of which can also occur with venom from some species. Methods: This was a retrospective chart review of patients admitted to a quaternary care academic hospital (Banner – University Medical Center Phoenix) in the southwestern United States for treatment of rattlesnake envenomation, over an approximately 1-year period from March 2017 through April 2018. Patients who had thromboelastography with platelet studies (TEG® with PlateletMapping®) during their care were included. Results: Twelve patients were identified for this study. Four patients exhibited inhibition of ADP-induced platelet activation: one had normal fibrinogen and platelet count, two had concurrent hypofibrinogenemia, and one had concurrent thrombocytopenia. Crotalidae polyvalent immune Fab (ovine) reversed platelet inhibition in the single patient for whom serial thromboelastographs were available. Fibrinolysis was present in seven patients and resolved in the two patients with serial thromboelastographs. Conclusions: Inhibition of ADP-induced platelet aggregation and fibrinolysis occurred independent of hypofibrinogenemia and thrombocytopenia, indicating fibrinogen concentration (or protime) and platelet count monitoring alone is insufficient to assess the extent of hematologic toxicity in rattlesnake envenomation. Crotalidae polyvalent immune Fab (ovine) reversed platelet inhibition in one case, suggesting platelet inhibition could also be used in treatment decisions. Fibrinolysis could also be reversed, although the timing to antivenom administration was less clear. [ABSTRACT FROM AUTHOR]

The article discusses the effectiveness of low-dose aspirin therapy in preventing myocardial infarction and the differential platelet reactivity in men and women. The clinical trial measures platelet aggregation to arachidonic acid, adenosine diphosphate, epinephrine, and platelet function analyzer closure time. The outcome measure for cardioprotection is sex differences in cyclooxygenase 1 platelet activation pathways. Data shows participants' baseline characteristics and platelet aggregation in postmenopausal women, as well as the results of predictive linear regression models. Researchers found that women and men have similar platelet reactivity, and concluded that most women do benefit from aspirin therapy. [ABSTRACT FROM AUTHOR]

The author reflects on the results of the study which examines the effect of milrinone infusion on fibrin formation and monocyte and platelet function on patients with knee arthroplasty in the U.S. The author explains that the study failed to determine the difference in blood loss in the milrinone treated group. The author claims that the study's results were unclear and asserts that milrinone should not be used as an antithrombotic agent.

The article discusses the evaluation of antiplatelet agent ticagrelor against clopidogrel in the clinical study of patients with acute coronary syndromes (ACS) in the U.S. Study shows that ticagrelor binds reversibly to adenosine diphosphate (ADP) P2Y receptors on platelets and inhibit platelet activation and eventual aggregation. It points out that the benefits of ticagrelor over clopidogrel were consistent on the study's subgroups.