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Background Critically ill patients with coronavirus disease 2019 (COVID‐19) are prone to developing macrothrombosis and microthrombosis. COVID‐19 has been reported to be rarely associated with thrombotic microangiopathies. A disintegrin and metalloprotease with thrombospondin type I repeats, member 13 (ADAMTS13) severe deficiency, the hallmark of thrombotic thrombocytopenic purpura (TTP), induces the formation of platelet, unusually large von Willebrand factor (VWF) multimer microthrombi. In immune‐mediated TTP, ADAMTS13 adopts specifically an open conformation. The VWF/ADAMTS13 couple may contribute to the microthrombi formation in pulmonary alveolar capillaries in COVID‐19. Objective To investigate clinical features, hemostatic laboratory parameters, VWF/ADAMTS13 axis, and ADAMTS13 conformation in critically ill COVID‐19 patients at admission. Methods Fifty three critically ill COVID‐19 patients were enrolled between March 18 and May 9 2020 in a monocentric hospital. Results The median age was 59 years and the male‐to‐female ratio was 2.8/1. We reported seven pulmonary embolisms and 15 deaths. Biological investigations showed increased fibrinogen and factor V levels, and strongly increased D‐dimers correlated with mortality. No patient presented severe thrombocytopenia nor microangiopathic hemolytic anemia. An imbalance between high VWF antigen levels and normal or slightly decreased ADAMTS13 activity levels (strongly elevated VWF/ADAMTS13 ratio) was correlated with mortality. Three patients had a partial quantitative deficiency in ADAMTS13. We also reported a closed conformation of ADAMTS13 in all patients, reinforcing the specificity of an open conformation of ADAMTS13 as a hallmark of TTP. Conclusion We suggest that slightly decreased or normal ADAMTS13 activity and highly elevated VWF are rather biomarkers reflecting both the strong inflammation and the endothelial damage rather than drivers of the thrombotic process of COVID‐19.

Acquired hemophilia A is a rare autoimmune disease, linked to the appearance of autoantibodies directed against circulating factor VIII, and characterized by a major hemorrhagic syndrome. Acquired hemophilia A is a life-threatening diagnostic and therapeutic medical emergency. We describe here the cohort of patients with acquired hemophilia A treated between 2015 and 2020 at Lariboisiere and Saint-Louis University Hospitals (Paris, France). We remind you here of the measures to be taken without delay in the face of any clinical and/or biological suspicion. Management is based on three main areas published in multicentre cohort studies, essentially observational: symptomatic treatment to control the hemorrhagic syndrome, immunosuppressive treatment to eradicate autoantibodies and manage their possible complications, and etiological treatment of the underlying pathology for secondary forms.

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A five-year-old boy is presented to Necker hospital for a dilated hypertrophic cardiomyopathy. The implantation of the Berlin Heart Excor® ventricular assist device was performed. This pediatric-sized Berlin Heart® device provides mechanical support for young infants and children of all ages to sustain the failing cardiac circulation over several months, until either recovery of myocardial function or heart transplantation. It remains difficult to identify patients with sufficient recovery and the right time for explantation of the Berlin Heart®. Currently, the decision as to whether a patient should be weaned from the system is mainly based on echocardiographic data. Humoral biomarker, associated to echocardiographic features, would be helpful to identify children who might recover without heart transplantation. We observed that our young patient presented highly elevated BNP plasma levels before mechanical support, and a significant decrease during Berlin Heart® support. Monitoring levels of BNP can be helpful to detect appropriate unloading of the heart as a precondition for recovery. During pump-stop maneuvers, BNP should be regarded in combination with clinical and hemodynamic status of the patients, associated with echocardiographic data.

A five-year-old boy is presented to Necker hospital for a dilated hypertrophic cardiomyopathy. The implantation of the Berlin Heart Excor