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Abstract Objectives To compare the performance of the TEG 5000 and TEG 6S Global Hemostasis cartridge. Methods We reviewed validation data of the TEG 5000 and TEG 6S Global Hemostasis cartridge. The specimens were analyzed in parallel according to the manufacturer’s operating instructions. Results Fifty-four healthy donors and 13 donors with known hemostatic abnormalities were included. The correlations between instrument types were only moderate—the Spearman rank correlations were 0.55, 0.62, 0.64, and 0.72, respectively, for CK R, K, angle, and maximum amplitude (MA) parameters. Using the manufacturer’s device-specific reference ranges to classify results as normal/abnormal, there was weak agreement in the qualitative interpretation of all parameters (Cohen’s κ for agreement for CK R, K, angle, and MA was 0.418, 0.154, –0.083, and 0.127, respectively). This could lead to discordant transfusion decisions. Conclusions These findings indicate that the TEG 5000 and TEG 6S may not be used interchangeably.

Background Fibrinolysisis is essential for vascular blood flow maintenance and is triggered by endothelial and platelet release of tissue plasminogen activator (t-PA). In certain critical conditions, e.g. sepsis, acute respiratory failure (ARF) and trauma, the fibrinolytic response is reduced and may lead to widespread thrombosis and multi-organ failure. The mechanisms underpinning fibrinolysis resistance include reduced t-PA expression and/or release, reduced t-PA and/or plasmin effect due to elevated inhibitor levels, increased consumption and/or clearance. This study in critically ill patients with fibrinolysis resistance aimed to evaluate the ability of t-PA and plasminogen supplementation to restore fibrinolysis with assessment using point-of-care ClotPro viscoelastic testing (VET). Methods In prospective, observational studies, whole-blood ClotPro VET evaluation was carried out in 105 critically ill patients. In 32 of 58 patients identified as fibrinolysis-resistant (clot lysis time > 300 s on the TPA-test: tissue factor activated coagulation with t-PA accelerated fibrinolysis), consecutive experimental whole-blood VET was carried out with repeat TPA-tests spiked with additional t-PA and/or plasminogen and the effect on lysis time determined. In an interventional study in a patient with ARF and fibrinolysis resistance, the impact of a 24 h intravenous low-dose alteplase infusion on coagulation and fibrinolysis was prospectively monitored using standard ClotPro VET. Results Distinct response groups emerged in the ex vivo experimental VET, with increased fibrinolysis observed following supplementation with (i) t-PA only or (ii) plasminogen and t-PA. A baseline TPA-test lysis time of > 1000 s was associated with the latter group. In the interventional study, a gradual reduction (25%) in serial TPA-test lysis times was observed during the 24 h low-dose alteplase infusion. Conclusions ClotPro viscoelastic testing, the associated TPA-test and the novel experimental assays may be utilised to (i) investigate the potential mechanisms of fibrinolysis resistance, (ii) guide corrective treatment and (iii) monitor in real-time the treatment effect. Such a precision medicine and personalised treatment approach to the management of fibrinolysis resistance has the potential to increase treatment benefit, while minimising adverse events in critically ill patients. Trial registration : VETtiPAT-ARF, a clinical trial evaluating ClotPro-guided t-PA (alteplase) administration in fibrinolysis-resistant patients with ARF, is ongoing (ClinicalTrials.gov NCT05540834 ; retrospectively registered September 15th 2022).

Viscoelastic-based techniques to evaluate whole blood hemostasis have advanced substantially since they were first developed over 70 years ago but are still based upon the techniques first described by Dr. Hellmut Hartert in 1948. Today, the use of thromboelastography, the method of testing viscoelastic properties of blood coagulation, has moved out of the research laboratory and is now more widespread, used commonly during surgery, in emergency departments, intensive care units, and in labor wards. Thromboelastography is currently a rapidly growing field of technological advancement and is attracting significant investment. This review will first describe the history of the viscoelastic testing and the established first-generation devices, which were developed for use within the laboratory. This review will then describe the next-generation hemostasis monitoring devices, which were developed for use at the site of care for an expanding range of clinical applications. This review will then move on to experimental technologies, which promise to make viscoelastic testing more readily available in a wider range of clinical environments in the endeavor to improve patient care.

Cirrhosis causes significant coagulopathy. Traditional coagulation tests may not accurately measure coagulopathy in well-compensated patients with cirrhosis. Viscoelastic tests are functional tests that may better assess coagulopathy in cirrhotic patients. We searched PubMed, ScienceDirect, Google Scholar, and grey literature using terms meaning viscoelastic testing and cirrhosis. After reviewing over 500 titles and abstracts, 40 full-text papers met inclusion criteria. Twenty-two papers found viscoelastic testing was a better indicator of baseline coagulation than traditional testing in cirrhosis. Nineteen additional papers evaluated the utility of peri-procedural viscoelastic testing and found they led to a reduction in blood product administration without increasing risk of hemorrhage, thrombotic events, or other complications. The usage of viscoelastic testing in patients with cirrhosis allows for better assessment of coagulopathy, resulting in improved outcomes. Educating physicians to optimize care of this high-risk group is necessary to further improve their treatment. •Viscoelastic methods (VEM) proficiently assess coagulopathy of cirrhotic patients.•Conventional coagulation tests may poorly assess coagulopathy in cirrhotic patients.•VEM is more fit to assess the need to transfuse in patients with cirrhosis.•VEM better indicates which blood components to transfuse in cirrhotic patients.

Abstract Objectives The sensitivity and specificity of clot lysis at 30 minutes after maximum clot strength (LY30), as measured by thromboelastography (TEG), for clinically significant hyperfibrinolysis have not been compared across the 2 US Food and Drug Administration–approved instruments (the TEG 5000 and TEG 6s [Haemonetics]). Methods We performed a retrospective, single-center analysis of these 2 instruments using the kaolin (CK) reagent. Results Local verification studies showed that the TEG 5000 and TEG 6s CK LY30 upper limits of normal (ULNs) were distinct (5.0% and 3.2%, respectively). Retrospective analysis of patient data showed that abnormal LY30 was 6 times more prevalent with the TEG 6s than with the TEG 5000 instrument. LY30 was a significant predictor of mortality with both instruments (TEG 6s: receiver operating characteristic [ROC] area under the curve [AUC] = 0.836, P ≤ .0001; TEG 5000: ROC AUC = 0.779, P = .028). The optimal LY30 cut point was determined based on these mortality data for each instrument. The TEG 6s showed superior mortality prediction than the TEG 5000 at lower LY30 levels (≥10%), with likelihood ratios of 8.22 and 2.62 for the TEG 6s and TEG 5000, respectively. Patients with a TEG 6s CK LY30 of 10% or higher were significantly more likely to die, receive cryoprecipitate, receive transfusions, or receive massive transfusion than patients with a TEG 6s LY30 of 3.3% to 9.9% (all P < .01). Patients with a TEG 5000 LY30 of 17.1% or higher were significantly more likely to die or use cryoprecipitate (P < .05); transfusion and massive transfusion protocol were not significantly different. Whole blood spiking studies showed that 70 ng/mL tissue plasminogen activator (tPA) achieved an average LY30 of approximately 10% for both instruments. Conclusions CK LY30 above the ULN is a sensitive but not specific cutoff for hyperfibrinolysis. At least moderately elevated CK LY30 carries more clinical portent on the TEG 6s instrument than on the TEG 5000. These TEG instruments are not sensitive to low concentrations of tPA.

Abstract Sorafenib is a multi-kinase inhibitor increasingly used in veterinary oncology, but information regarding its potential adverse hematologic effects in dogs remains limited. A 50 kg neutered male Labrador Retriever with previously treated intranasal sarcoma was treated with sorafenib (5 mg/kg PO q24h) based on tyrosine kinase receptor profiling that identified 60% overexpression of platelet-derived growth factor receptor. The dog remained clinically stable for 132 days before developing worsening nasal discharge, increased epistaxis, and respiratory effort. Hematologic testing identified a platelet count of 130 × 103/μL with clumping, normal prothrombin time, activated partial thromboplastin time, and normal D-dimer concentration. Computed tomography did not indicate appreciable tumor progression. Viscoelastic assessment demonstrated delayed clot initiation and markedly decreased clot development and firmness, consistent with a hypocoagulable profile. Sorafenib was discontinued, and serial viscoelastic testing on days 149, 170, and 191 showed progressive improvement with normalization of clot parameters, paralleling the resolution of clinical signs. This case documents reversible, sorafenib-associated coagulopathy in a dog and illustrates the diagnostic utility of viscoelastic testing when evaluating worsening epistaxis in dogs receiving tyrosine kinase inhibitors.

Background Severe haemorrhage remains a leading cause of maternal mortality worldwide, despite advancements in obstetric care. Although viscoelastic testing is recommended to guide treatment of postpartum haemorrhage, device-specific physiological parameters and reference ranges specific to pregnancy are necessary to enable accurate interpretation of viscoelastic findings in the clinical management of obstetric patients. Evaluation of ClotPro ® , including comparison with conventional laboratory assays and with non-pregnant individuals, is therefore essential to support its use in obstetric patients. Methods In this prospective study, venous blood samples were obtained from 130 parturient participants before labour and 45 non-pregnant controls. Samples were analysed with conventional laboratory coagulation tests and the ClotPro ® device. ClotPro ® parameters and conventional laboratory tests were compared between the parturient population and non-pregnant control group with Student’s t-test or the Mann-Whitney U test, as appropriate. The correlation between selected laboratory and coagulation parameters was assessed with Spearman’s correlation coefficient. Reference ranges for ClotPro ® in parturients were established by calculation of percentiles 2.5 and 97.5. Results Significant statistical differences in clot firmness were found across the EX-test, IN-test, and FIB-test ( p  < 0.006) between parturient and non-pregnant participants. The most pronounced differences were observed in the FIB-test. Strong correlation was observed between conventional laboratory tests and FIB-test (Rs = 0.657, p  < 0.001 in the pregnant group; Rs = 0.669, p  < 0.001 in the control group). According to our findings, reference ranges were established for the parturient population: EX-test, CT (39–67 s), A5 (39–59 mm), ML (1–9%), MCF (57–70 mm); FIB-test, A5 (15–29 mm), MCF (19–35 mm); and IN-test, CT (121–172 s). Conclusion Pregnant women exhibit a distinct ClotPro ® coagulation profile, characterised by increased clot firmness in FIB-test, supported by correlations with standard laboratory tests and parturient-specific reference intervals. These findings enhance the physiological interpretation of ClotPro ® in obstetric care and may support its future integration into postpartum haemorrhage management.

Background Monitoring of unfractionated heparin (UFH) in critically ill patients is challenging due to disease-related alterations of the coagulation system, directly affecting conventional laboratory tests, including activated partial thromboplastin time (aPTT). Measurement of anti-factor Xa activity (Anti-Xa) as an alternative to aPTT often lacks 24/7 availability. Whole blood viscoelastic testing (VET) may provide a feasible point-of-care alternative to guide UFH dosing in this setting. Additionally, VET is readily available in the environment found in our clinic, The aim of this study was to evaluate the diagnostic performance of viscoelastic testing compared with activated partial thromboplastin time for monitoring unfractionated heparin in critically ill patients and to define clinically applicable viscoelastic thresholds using anti-factor Xa activity as the reference standard. Methods In this prospective observational study for UFH monitoring Anti-Xa, aPTT, and the VET clotting time IN/HI ratio (ClotPro®; Haemonetics, Boston, MA, USA) were determined in simultaneously taken blood samples. Anti-Xa results were used as the reference standard to categorize ongoing UFH anticoagulation intensity into four categories (prophylactic, sub-therapeutic, therapeutic, and overdosed). Diagnostic performance of aPTT and CT IN/HI ratio were evaluated against Anti-Xa using ROC analysis and Cohen’s Kappa. Test performance was evaluated using ROC analysis, multiclass classification, and weighted Cohen’s kappa. Results Between September 2020 and July 2022, 466 datasets from 75 ICU patients receiving intravenous UFH were analyzed. Compared to aPTT, AUC values for CT IN/HI were higher for detecting prophylactic (0.817 vs. 0.726), therapeutic (0.690 vs. 0.494) and overdosed (0.845 vs. 0.708) UFH levels. Thresholds of > 1.4, > 1.9, and > 2.3 for the CT IN/HI ratio corresponded to sub-therapeutic, therapeutic, and overdosed ranges, respectively. The CT IN/HI ratio showed moderate agreement with Anti-Xa classification (κ = 0.450), while aPTT agreement was insufficient (κ = 0.220). Conclusions The CT IN/HI ratio offers a reliable point-of-care alternative to standard UFH monitoring, in the case it is readily available. It provides better alignment with Anti-Xa activity than aPTT and may improve anticoagulation management in critically ill patients, especially when Anti-Xa testing is delayed or unavailable. Trial registration DRKS-ID DRKS00028689 ( https://drks.de/search/de ), PI: Lars Heubner, retrospectively registered 30.03.2022.

Platelets form the nidus around which the primary hemostatic cascade is amplified and propagated. Desmopressin (DDAVP) has been shown to enhance platelet function through interaction with the endothelium. Evidence suggests that an alternative mechanism of action may exist. We aimed to determine the effect of DDAVP on platelet function and microclotting of plasma proteins in samples from healthy volunteers. We analyzed blood samples in 20 healthy volunteers with no coagulation abnormalities. Control and test samples were drawn from each participant. DDAVP was added in vitro to test samples. All samples were subjected to PFA‐200, viscoelastic (VET) and fluorescence microscopy testing. DDAVP increased TEG MA and decreased K‐time in experimental samples. There was no difference between the means in the clotting times in either of the PFA‐200 groups. Fluorescence microscopy examining platelet activation and microclot formation showed significant increases in both parameters in the test samples. The results contrast current literature, which suggests that DDAVP has no effect on platelet function independent of the endothelium. This is the first study demonstrating an in vitro effect of DDAVP on platelets examined by VET and microscopy. We conclude that a relationship exists between DDAVP exposure, in vitro, platelet activation and microclot formation.

Viscoelastic testing is increasingly being used in clinical and research settings to assess hemostasis. Indeed, there are potential situations in which viscoelastic testing is reportedly superior to standard routine laboratory testing for hemostasis. We report the current testing platforms and terminology, as well as providing a concise narrative review of the published evidence to guide its use in various clinical settings. Notably, there is increasing evidence of the potential utility of viscoelastic testing for assessment of direct oral anticoagulants, and bleeding associated with chronic liver disease, orthotopic liver transplantation, cardiac surgery, trauma, obstetrics and pediatrics.