key: cord-341580-ymzlhsai authors: Almskog, L.; Wikman, A.; Svensson, J.; Wanecek, M.; Bottai, M.; van der Linden, J.; Agren, A. title: Rotational Thromboelastometry predicts care level in Covid-19 date: 2020-06-12 journal: nan DOI: 10.1101/2020.06.11.20128710 sha: doc_id: 341580 cord_uid: ymzlhsai Background High rates of thrombotic events in severely ill COVID-19 patients have been reported. Pulmonary embolism as well as microembolisation of vital organs may be direct causes of death in COVID-19 positive individuals. If patients at high risk of developing thrombosis may be identified early, more effective prophylactic treatment could be applied. Objectives To test whether Rotational Thromboelastometry (ROTEM) indicates hypercoagulopathy in hospitalized COVID-19 patients, and whether patients with severe disease have a more pronounced hypercoagulopathy compared with less severely ill patients. Methods COVID-19 positive patients over 18 years admitted to St Gorans Hospital, Stockholm, Sweden 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 as soon after admission to hospital as possible (median day 1 after hospitalization). The data were compared with healthy controls. Results The ROTEM variables Maximum Clot Firmness (EXTEM-MCF and FIBTEM-MCF) were significantly higher in both groups of 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 significantly longer and Clot Formation Time (EXTEM-CFT) significantly 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 (EXTEM-MCF, FIBTEM-MCF, EXTEM-CT, EXTEM-CFT) 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 could be a potentially useful predictor of thromboembolic complications and mortality in these patients. Corona virus disease 2019 , caused by the novel corona virus SARS-CoV-2, has the last few months taken hold of the world and spread as a global pandemic with presently more than 5.5 million cases 1 . The lungs are the main target organ for COVID-19, and p atients who become critically ill generally suffer from respiratory distress leading to difficulties in ventilation and oxygenation. However, the respiratory symptoms in COVID-19 display atypical features, which have challenged the conventional mechanical ventilation strategies 2 . A recent Dutch study of 184 COVID-19 positive patients treated at intensive care units (ICUs) showed a cumulative incidence of thrombotic events of 49%, mainly pulmonary embolism 2 . Autopsy reports have confirmed and even exceeded this high rate of thrombosis 3, 4 , and have also shown a high prevalence of microthrombosis in the small veins of the lungs 5 . Thromboembolic complications may be a direct cause of death in COVID-19 3, 4 and in addition, the loss of perfusion caused by thrombi in the lungs will impair pulmonary gas exchange independently of the direct tissue damage caused by the viral pneumonia. This will contribute to the respiratory failure that is the main cause of critical disease in patients with COVID-19. Elevated levels of fibrin degradation products (e.g. d-dimer) have consistently been reported as a strong prognostic factor associated with poor outcome in patients with COVID-19 6, 7 . This suggests a general coagulation activation and secondary hyperfibrinolysis. However, the D-dimer increase is not evident in early stages of the disease 7 , limiting its usefulness as a prognostic marker. Maximum clot firmness (MCF) may be calculated using Rotational Thromboelastometry (ROTEM) and is considered a good marker for hypercoagulopathy 8 . Theoretically, ROTEM variables may be affected earlier during the disease course compared with d-dimer and may be of greater value as a predictor of disease severity. Studies assessing ROTEM in COVID-19 patients treated at ICUs have shown elevated MCF values 9, 10 . However, no ROTEM data at earlier stages of the disease have, to our knowledge, yet been reported. The aim of this study was to assess the presence of coagulopathy, measured by ROTEM, in COVID-19 patients at hospital admission. The study was designed as a prospective observational study and was approved by the Swedish Ethical Review Authority (D-nr 2020-01875). Patients over 18 years of age, who tested positive for COVID-19 and were considered in need of hospital care were eligible for inclusion in the study. Recruitment of patients commenced May 8th, 2020, and is planned to continue for three months in total. Here we report on subjects included up to May 31st, 2020. All patients were included at Capio St Göran's Hospital (StG) in Stockholm, Sweden. Patients presenting at StG Emergency Room with confirmed SARS-CoV-2 infections and in need of hospitalization are admitted either to regular wards with possibility of low-flow oxygen therapy (henceforth "Regular ward") or to wards with possibilities of specialized ventilation support; either non-invasive ventilation in intermediate wards (Biphasic Positive Airway Pressure (BiPAP) or High-Flow Oxygen Therapy (HFOT)) or to the Intensive Care Unit where, in addition to BiPAP and HFOT, mechanical ventilation support is provided (henceforth "Specialized wards"). Coagulation-related blood tests were drawn from all included patients (d-dimer, P-fibrinogen, APTT, INR, antithrombin, platelet count and ROTEM) as soon after admission to hospital as possible. ROTEM test results were blinded for clinicians, but conventional coagulation tests were not. Relevant patient information was extracted from the medical journals. Aside from these blood tests, nothing was changed in the routine care of included patients. Anticoagulant treatment (ACTr) after admission were divided into 5 groups: 0 (no treatment), 1 (low prophylactic dose LMWH = 75 IE/kg/24h), 2 (high prophylactic dose LMWH = 150 IE/kg/24h), 3 (treatment dose LMWH ≥ 200 IE/kg/24h) and 4 (pre-existing anticoagulant medication, e.g. new oral anticoagulants). A ROTEM sigma (Tem Innovations GmbH, Germany) analyzing instrument was installed for the purpose of the study at StG laboratory. ROTEM sigma is a fully automated system with proven ROTEM technology, where pipetting and test preparation are not required. Analyzing time is 45-60 min for each test. All blood samples were analyzed within four hours after they were drawn. ROTEM data from healthy individuals collected 2011-2012 for a previously published study were used as controls. The original publication contains further details 11 . . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 12, 2020. . Two of four ROTEM-tests are presented here: i) extrinsically activated assays with tissue factor (EXTEM); ii) with tissue factor and the platelet inhibitor cytochalasin D (FIBTEM) 12 . EXTEM tests the extrinsic coagulation pathway. FIBTEM blocks the platelet contribution to clot formation, leaving only the impact of clotting proteins and the functional fibrinogen. Coagulation Time (CT) is the time (in seconds) from test start until an amplitude of 2 mm is reached, giving information about coagulation activation/initiation. Clot Formation Time (CFT) is the time (in seconds) between 2 mm amplitude and 20 mm amplitude, giving information about clot propagation. Maximum Clot Firmness (MCF) is the maximum amplitude (in millimeters) reached during the test, giving information about clot stability. A short EXTEM-CFT and an increased EXTEM-MCF and/or FIBTEM-MCF suggest a hypercoagulable state. All continuous variables are presented as median and interquartile range (IQR). Kruskal-Wallis tests were used to test whether ROTEM data for COVID-19 patients differed depending on care level (Regular ward; Specialized ward), or from healthy controls. If the tests were significant, pairwise two-sided Wilcoxon tests were performed. Spearman's correlation coefficients were calculated to assess associations between variables. P-values below 0.05 were considered statistically significant. No corrections for multiple comparisons were made. R version 4.0.0 was used to perform statistical analysis and visualizations. Sixty COVID-19 positive patients and 89 healthy controls were included in the analysis. Table 1 presents patient characteristics. Comorbidities were common within the COVID-19 patient group, where 42% of patients had a prior diagnosis of hypertension and 28% of diabetes. 48 patients (80%) received prophylactic anticoagulant treatment (ACTr) after admission, whereof in 36 (60%) patients this treatment was administered before ROTEM was analyzed. Of patients with ACTr before ROTEM, 19 of these had low dose prophylaxis with Low Molecular Weight Heparin (LMWH), 7 had high dose prophylaxis with LMWH, 5 had treatment dose LMWH and 5 continued their regular anticoagulant medication. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 12, 2020. . Figure S1 and S2. For EXTEM-CT, the Kruskal-Wallis test showed a significant difference between the groups (H(2) = 97.1, p < 0.001). Post-hoc pairwise Wilcoxon tests showed that COVID-19 patients (both care levels) had significantly longer coagulation time compared with healthy controls (p<0.001) and that subjects treated at specialized wards had longer coagulation time compared with subjects treated at regular wards (p<0.001) ( Figure 1A ). For EXTEM-MCF, the Kruskal-Wallis test showed a significant difference between the groups (H(2) = 39.3, p < 0.001). Post-hoc pairwise Wilcoxon tests showed that . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128710 doi: medRxiv preprint COVID-19 patients (both care levels) had significantly increased maximum clot amplitude compared to healthy controls (p<0.001) and that subjects treated at specialized wards had increased maximum clot amplitude compared with subjects treated at regular wards (p<0.01) ( Figure 1B ). For EXTEM-CFT, the Kruskal-Wallis test showed a significant difference between the groups (H(2) = 64.8, p < 0.001). Post-hoc pairwise Wilcoxon tests showed that COVID-19 patients (both care levels) had significantly shorter clot formation time compared to healthy controls (p<0.001) ( Figure 1C ). For FIBTEM-MCF, the Kruskal-Wallis test showed a significant difference between the groups (H(2) = 79.5, p < 0.001). Post-hoc pairwise Wilcoxon tests showed that COVID-19 patients (both care levels) had significantly increased maximum clot amplitude compared with healthy controls (p<0.001) and that subjects treated at specialized wards had increased maximum clot amplitude compared with subjects treated at regular wards (p=0.04) ( Figure 1D ). . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 12, 2020. . p-values were calculated using a two-sided Wilcoxon signed rank test (ns = p > 0.05, * = p < 0.05, * * = p < 0.01, * * * = p < 0.001", * * * * = p < 0. To assess the association between D-dimer and EXTEM-MCF, and P-Fibrinogen and FIBTEM-MCF at an early stage of the disease, Spearman's correlation coefficient was calculated for the subset of data where ROTEM data was available from the first day after hospital admission (N=34). There was no significant correlation between D-dimer and EXTEM-MCF (correlation = 0.02, p = 0.9). The correlation between P-Fibrinogen and FIBTEM-MCF was significant (correlation = 0.84, p < 0.001) (Figure 2 ). Our results show that the median patient with COVID-19 related mild to severe acute respiratory distress treated at StG between 200508-200531, had laboratory results indicating coagulopathy, with significant differences in ROTEM variables compared . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128710 doi: medRxiv preprint with healthy controls; longer EXTEM-CT, shorter EXTEM-CFT and increased EXTEM-MCF and FIBTEM-MCF. This suggests a patient with prolonged haemostatic initiation, shortened clot propagation and, notably, with a pronounced clot firmness indicating hypercoagulation. Fibrinolysis measured by clot lysis (Lysis index at time 30 minutes, LI30) was however not significantly increased. In this prospective observational study we assessed the level of coagulopathy in COVID-19 patients using ROTEM analysis. Previous studies have shown deranged values in critically ill patients 9, 10 . To our knowledge, this is the first time data on less severely ill patients in the first 1-2 days after admission to hospital are published. In our sample, we observed significantly higher EXTEM-MCF and FIBTEM-MCF in patients treated at regular wards compared with healthy controls. This indicates that coagulopathy is present early in the disease course, and suggests that ROTEM-analysis may potentially be a useful predictor of thromboembolic complications and mortality. During the months since COVID-19 was classified as a pandemic, evidence has emerged indicating coagulopathy and thrombosis as central explanations to why some patients develop severe illness 2,3 . The pattern of higher EXTEM-MCF and FIBTEM-MCF in more severely ill patients in our data strengthens this hypothesis that the atypical features of Acute Respiratory Distress Syndrome (ARDS) observed in COVID-19 patients may partly be caused by thromboembolism impairing lung perfusion. In line with these findings, increased D-dimer and P-fibrinogen have been reported to predict poor clinical outcome 6, 7 . However, both these tests have caveats: the D-dimer blood test is nonspecific and may be increased in a variety of conditions including malignancy, inflammation and infection 13 ; fibrinogen is an acute phase reactant, and high levels of P-fibrinogen may reflect a patient with a high inflammatory profile, which itself may amplify the effects of other cardiovascular risk factors 14 . Conversely, ROTEM has been shown a better tool for monitoring coagulation profiles than conventional coagulation tests 15, 16 . As can be seen in Figure 2 , FIBTEM-MCF and P-fibrinogen are highly correlated in COVID-19 patients, whereas EXTEM-MCF supplies information that differs from D-dimer at an early disease stage. If individuals at risk of developing COVID-19 related thromboses are identified at an early stage, enhanced prophylaxis with LMWH may decrease mortality in this group of patients 6 17 . It is feasible that ROTEM . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted June 12, 2020. . could be applied for this purpose. Whether the ROTEM data will have better predictive characteristics compared with conventional coagulation tests does, however, remain to be shown. Sepsis is known to exert a complex effect on the coagulation system, generally affecting all aspects of clot formation, kinetic activity and clot development 18 . Already in the early stages of sepsis the coagulation system and the platelets are strongly activated 19 . However, it has been recently shown that the coagulopathy related to the COVID-19 pathogenesis differs from the disseminated intravascular coagulation (DIC) associated with sepsis, with relatively normal levels of INR, APTT and platelets despite markedly elevated d-dimer levels 20 21 . Our results confirm these findings. Nevertheless, whether this hypercoagulability is due to the characteristics of the invading microorganism, the individual viral load, or the massive host inflammatory response remains unknown. The coagulopathy related to COVID-19 ARDS may in some way be specific for the SARS-CoV-2 species, representing new features that need to be further explored. Our study has limitations. First, 60% of patients had received usually low dose anticoagulant treatment before ROTEM analysis, which may have to some degree counteracted hypercoagulation. However, despite this limitation, ROTEM results were highly significantly increased in covid-19 patients compared with normal controls. Second, not all patients admitted for COVID-19 at St Göran's Hospital during this period were tested using ROTEM, and not all patients that were included were tested during the first day after admission. The main reasons for this were: (i) Due to clinical duties the physicians responsible for the study were not always able to scan the wards for new patients on a daily basis (ii) and more importantly, limitation of the testing equipment, with possibility to run a maximum of 6 tests every 4 hours. Still, we believe that the included patients are a representative cross-section of the COVID-19 patients treated at St Göran's Hospital during the study period. In hospitalized COVID-19 positive patients, elevated values of EXTEM-MCF and FIBTEM-MCF were seen at admission to hospital. This pattern was more pronounced in patients with significantly increased disease severity who needed transfer to specialized wards and is likely reflecting a hypercoagulable state. Whether early ROTEM-analysis at admission to hospital may predict outcome . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted June 12, 2020. . https://doi.org/10.1101/2020.06.11.20128710 doi: medRxiv preprint (mortality, thrombosis) in COVID-19 positive patients will be analyzed at a later stage of this research project. World Health Organization Confirmation of the high cumulative incidence of thrombotic complications in critically ill ICU patients with COVID-19: An updated analysis Autopsy Findings and Venous Thromboembolism in Patients With COVID-19 Pulmonary Arterial Thrombosis in COVID-19 With Fatal Outcome: Results From a Prospective Post-mortem examination of COVID19 patients reveals diffuse alveolar damage with severe capillary congestion and variegated findings of lungs and other organs suggesting vascular dysfunction Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study Application of ROTEM to assess hypercoagulability in patients with lung cancer COVID-19-Related Severe Hypercoagulability in Patients Admitted to Intensive Care Unit for Acute Respiratory Failure Evaluation of coagulation function by rotation thromboelastometry in critically ill patients with severe COVID-19 pneumonia Detection of elevated INR by thromboelastometry and thromboelastography in warfarin treated patients and healthy controls FIBTEM provides early prediction of massive transfusion in trauma Chapter 142 -Venous Thromboembolism A retrospective register study comparing fibrinogen treated trauma patients with an injury severity score matched control group. Scand A systematic review on the rotational thrombelastometry (ROTEM®) values for the diagnosis of coagulopathy, prediction and guidance of blood transfusion and prediction of mortality in trauma patients A comparative study of viscoelastic hemostatic assays and conventional coagulation tests in trauma patients receiving fibrinogen concentrate Association of Treatment Dose Anticoagulation with In-Hospital Survival Among Hospitalized Patients with COVID-19 The effect of sepsis and septic shock on the viscoelastic properties of clot quality and mass using rotational thromboelastometry: A prospective observational study Coagulation system and platelets are fully activated in uncomplicated sepsis Pulmonary intravascular coagulation in COVID-19: possible pathogenesis and recommendations on anticoagulant/thrombolytic therapy Disseminated Intravascular Coagulation We wish to thank the staff at the COVID-19 wards and the Laboratory Unit at St Göran's Hospital for collaboration and involvement in this study, and colleagues at the Intensive Care Unit for support. Special thanks to Rasmus Berglind, Anton Borgström and Christine Carlswärd for valuable assistance with data collection. The authors declare no conflicts of interest.