High prevalence of thrombotic events in severely ill COVID-19 patients have been reported. Pulmonary embolism as well as microembolization of vital organs may in these individuals be direct causes of death. The identification of patients at high risk of developing thrombosis may lead to targeted, more effective prophylactic treatment. The primary aim of this study was to test whether rotational thromboelastometry (ROTEM) at admission indicates hypercoagulopathy and predicts the disease severity, assessed as care level, in COVID-19 patients. The study was designed as a prospective, observational study where COVID-19 patients over 18 years admitted to hospital were eligible for inclusion. Patients were divided into two groups depending on care level: (1) regular wards or (2) wards with specialized ventilation support. Conventional coagulation tests, blood type and ROTEM were taken at admission. 60 patients were included; age 61 (median), 67% men, many with comorbidities (e.g. hypertension, diabetes). The ROTEM variables Maximum Clot Firmness (EXTEM-/FIBTEM-MCF) were higher in COVID-19 patients compared with in healthy controls (p < 0.001) and higher in severely ill patients compared with in patients at regular wards (p < 0.05). Our results suggest that hypercoagulopathy is present early in patients with mild to moderate disease, and more pronounced in severe COVID-19 pneumonia. Non-O blood types were not overrepresented in COVID-19 positive patients. ROTEM variables showed hypercoagulopathy at admission and this pattern was more pronounced in patients with increased disease severity. If this feature is to be used to predict the risk of thromboembolic complications further studies are warranted.

Background: High prevalence of thrombotic events in severely ill COVID-19 patients have been reported. Pulmonary embolism as well as microembolization of vital organs may in these individuals be direct causes of death. The identification of patients at high risk of developing thrombosis may lead to targeted, more effective prophylactic treatment. Objectives: To test whether Rotational Thromboelastometry (ROTEM) indicates hypercoagulopathy in COVID-19 patients, and whether patients with severe disease have a more pronounced hypercoagulopathy compared with less severely ill patients. Methods: The study was designed as a prospective observational study where COVID-19 patients over 18 years admitted to hospital were eligible for inclusion. Patients were divided into two groups depending on care level: 1) regular wards or 2) wards with specialized ventilation support. ROTEM was taken after admission and the data were compared with ROTEM in healthy controls. Results: The ROTEM variables Maximum Clot Firmness (EXTEM-/FIBTEM-MCF) were higher in COVID-19 patients compared with healthy controls (p<0.001) and higher in severely ill patients compared with patients at regular wards (p<0.05). Coagulation Time (EXTEM-CT) was longer and Clot Formation Time (EXTEM-CFT) shorter in COVID-19 patients compared with healthy controls. Our results suggest that hypercoagulopathy is present in hospitalized patients with mild to severe COVID-19 pneumonia. Conclusion: ROTEM variables were significantly different in COVID-19 patients early after admission compared with healthy controls. This pattern was more pronounced in patients with increased disease severity, suggesting that ROTEM-analysis may be useful to predict thromboembolic complications in these patients.

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