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Background: Vascular anomalies comprise a diverse group of rare diseases with altered blood flow and are often associated with coagulation disorders. The most common example is a localized intravascular coagulopathy in venous malformations leading to elevated D-dimers. In severe cases, this may progress to a disseminated intravascular coagulopathy with subsequent consumption of fibrinogen and thrombocytes predisposing to serious bleeding. A separate coagulopathy is the Kasabach-Merritt phenomenon in kaposiform hemangioendothelioma characterized by platelet trapping leading to thrombocytopenia and eventually consumptive coagulopathy. Our previous work showed impaired von Willebrand factor and platelet aggregometry due to abnormal blood flow, i.e., in ventricular assist devices or extracorporeal membrane oxygenation. With altered blood flow also present in vascular anomalies, we hypothesized that, in particular, the von Willebrand factor parameters and the platelet function may be similarly impacted., Methods: We prospectively recruited 73 patients with different vascular anomaly entities and analyzed their coagulation parameters., Results: Acquired von Willebrand syndrome was observed in both of our patients with Kasabach-Merritt phenomenon. In six out of nine patients with complex lymphatic anomalies, both the vWF antigen and activity were upregulated. Platelet aggregometry was impaired in both patients with Kasabach-Merritt phenomenon and in seven out of eight patients with an arteriovenous malformation., Conclusions: The analysis of coagulation parameters in our patients with vascular anomalies advanced our understanding of the underlying pathophysiologies of the observed coagulopathies. This may lead to new treatment options for the, in part, life-threatening bleeding risks in these patients in the future.

The Haemostasis Traffic Light is a cognitive aid with a user-centred design to enhance and simplify situation awareness and decision-making during peri-operative bleeding. Its structure helps to prioritise therapeutic interventions according to the pathophysiology and the severity of the bleeding. This investigator-initiated, randomised, prospective, international, dual-centre study aimed to validate the Haemostasis Traffic Light by adapting it to the local coagulation protocols of two university hospitals. Between 9 January and 12 May 2020, we recruited 84 participants at the University Hospital Zurich, Switzerland, and the Italian Hospital of Buenos Aires, Argentina. Each centre included 21 resident and 21 staff anaesthetists. Participants were randomly allocated to either the text-based algorithm or the Haemostasis Traffic Light. All participants managed six bleeding scenarios using the same algorithm. In simulated bleeding scenarios, the design of the Haemostasis Traffic Light algorithm enabled more correctly solved cases, OR (95%CI) 7.23 (3.82-13.68), p < 0.001, and faster therapeutic decisions, HR (95%CI) 1.97 (1.18-3.29, p = 0.010). In addition, the tool improved therapeutic confidence, OR (95%CI) 4.31 (1.67-11.11, p = 0.003), and reduced perceived work-load coefficient (95%CI) -6.1 (-10.98 to -1.22), p = 0.020). This study provides empirical evidence for the importance of user-centred design in the development of haemostatic management protocols., (© 2020 Association of Anaesthetists.)

Point-of-care viscoelastic coagulation tests are used increasingly and enable physicians to run precise whole blood coagulation diagnostics. However, the somewhat complicated and abstract presentation of results may hinder these advantages. For this reason, we developed the Visual Clot as an alternative mode of presentation for thrombelastometric data. An algorithm takes existing parameters from rotational thromboelastometry and creates a visual representation in the form of an animated blood clot named 'Visual Clot'. In a prospective international dual-centre study, 60 physicians were presented with rotational thromboelastometry results in the standard way or as a Visual Clot. They were then asked to make therapeutic decisions based on pathological findings. Overall proportion of correct therapeutic decisions was median (IQR [range] 100 (83-100 [39-100]) % for Visual Clot vs. 44 (25-50 [0-83]) % for standard rotational thromboelastometry presentation of results, p < 0.001. Mixed regression models yielded a mean OR (95%CI) 22.1 (13.4-36.5), p < 0.001 for correct decisions with the Visual Clot compared with standard rotational thromboelastometry, with an 18.7 (16.4-21.1), p < 0.001 second decrease in decision time. Perceived cognitive work-load was lower, and participants rated their diagnostic confidence to be higher with the Visual Clot, both p < 0.001. Although correct interpretation of standard rotational thromboelastometry results depended on previous rotational thromboelastometry knowledge and experience, Visual Clot interpretation did not. The Visual Clot improved rotational thromboelastometry-based therapeutic decisions, as pathologies can be recognised more rapidly and accurately. These findings underline the significance of an alternative additional visualisation technique that simplifies the interpretation of abstract standard data., (© 2020 Association of Anaesthetists.)

This review provides a comprehensive and up-to-date overview of point-of-care (POC) devices most commonly used for coagulation analyses in the acute settings. Fast and reliable assessment of hemostasis is essential for the management of trauma and other bleeding patients. Routine coagulation assays are not designed to visualize the process of clot formation, and their results are obtained only after 30-90 m due to the requirements of sample preparation and the analytical process. POC devices such as viscoelastic coagulation tests, platelet function tests, blood gas analysis and other coagulometers provide new options for the assessment of hemostasis, and are important tools for an individualized, goal-directed, and factor-based substitution therapy. We give a detailed overview of the related tests, their characteristics and clinical implications. This review emphasizes the evident advantages of the speed and predictive power of POC clot measurement in the context of a goal-directed and algorithm-based therapy to improve the patient's outcome. Interpretation of viscoelastic tests is facilitated by a new visualization technology.