Randomized Trial of Anticoagulation Strategies for Noncritically Ill Patients Hospitalized With COVID-19.

BACKGROUND: Prior studies of therapeutic-dose anticoagulation in patients with COVID-19 have reported conflicting results. OBJECTIVES: We sought to determine the safety and effectiveness of therapeutic-dose anticoagulation in noncritically ill patients with COVID-19. METHODS: Patients hospitalized with COVID-19 not requiring intensive care unit treatment were randomized to prophylactic-dose enoxaparin, therapeutic-dose enoxaparin, or therapeutic-dose apixaban. The primary outcome was the 30-day composite of all-cause mortality, requirement for intensive care unit-level of care, systemic thromboembolism, or ischemic stroke assessed in the combined therapeutic-dose groups compared with the prophylactic-dose group. RESULTS: Between August 26, 2020, and September 19, 2022, 3,398 noncritically ill patients hospitalized with COVID-19 were randomized to prophylactic-dose enoxaparin (n = 1,141), therapeutic-dose enoxaparin (n = 1,136), or therapeutic-dose apixaban (n = 1,121) at 76 centers in 10 countries. The 30-day primary outcome occurred in 13.2% of patients in the prophylactic-dose group and 11.3% of patients in the combined therapeutic-dose groups (HR: 0.85; 95% CI: 0.69-1.04; P = 0.11). All-cause mortality occurred in 7.0% of patients treated with prophylactic-dose enoxaparin and 4.9% of patients treated with therapeutic-dose anticoagulation (HR: 0.70; 95% CI: 0.52-0.93; P = 0.01), and intubation was required in 8.4% vs 6.4% of patients, respectively (HR: 0.75; 95% CI: 0.58-0.98; P = 0.03). Results were similar in the 2 therapeutic-dose groups, and major bleeding in all 3 groups was infrequent. CONCLUSIONS: Among noncritically ill patients hospitalized with COVID-19, the 30-day primary composite outcome was not significantly reduced with therapeutic-dose anticoagulation compared with prophylactic-dose anticoagulation. However, fewer patients who were treated with therapeutic-dose anticoagulation required intubation and fewer died (FREEDOM COVID [FREEDOM COVID Anticoagulation Strategy]; NCT04512079).

External validation of the ADA score for predicting thrombosis among acutely ill hospitalized medical patients from the APEX Trial.

The ADA (Age-D-dimer-Albumin) score was developed to identify hospitalized patients at an increased risk for thrombosis in the coronavirus infectious disease-19 (COVID-19) setting. The study aimed to validate the ADA score for predicting thrombosis in a non-COVID-19 medically ill population from the APEX trial. The APEX trial was a multinational, randomized trial that evaluated the efficacy and safety of betrixaban vs. enoxaparin among acutely ill hospitalized patients at risk for venous thromboembolism. The study endpoints included the composite of arterial or venous thrombosis and its components. Metrics of model calibration and discrimination were computed for assessing the performance of the ADA score as compared to the IMPROVE score, a well-validated VTE risk assessment model. Among 7,119 medical inpatients, 209 (2.9%) had a thrombosis event up to 77 days of follow-up. The ADA score demonstrated good calibration for both arterial and venous thrombosis, whereas the IMPROVE score had adequate calibration for venous thrombosis (p > 0.05 from the Hosmer-Lemeshow test). For discriminating arterial and venous thrombosis, there was no significant difference between the ADA vs. IMPROVE score (c statistic = 0.620 [95% CI: 0.582 to 0.657] vs. 0.590 [95% CI: 0.556 to 0.624]; ∆ c statistic = 0.030 [95% CI: -0.022 to 0.081]; p = 0.255). Similarly, for discriminating arterial thrombosis, there was no significant difference between the ADA vs. IMPROVE score (c statistic = 0.582 [95% CI: 0.534 to 0.629] vs. 0.609 [95% CI: 0.564 to 0.653]; ∆ c statistic = -0.027 [95% CI: -0.091 to 0.036]; p = 0.397). For discriminating venous thrombosis, the ADA score was modestly superior to the IMPROVE score (c statistic = 0.664 [95% CI: 0.607 to 0.722] vs. 0.573 [95% CI: 0.521 to 0.624]; ∆ c statistic = 0.091 [95% CI: 0.011 to 0.172]; p = 0.026). The ADA score had a higher sensitivity (0.579 [95% CI: 0.512 to 0.646]; vs. 0.440 [95% CI: 0.373 to 0.507]) but lower specificity (0.625 [95% CI: 0.614 to 0.637] vs. 0.747 [95% CI: 0.737 to 0.758]) than the IMPROVE score for predicting thrombosis. Among acutely ill hospitalized medical patients enrolled in the APEX trial, the ADA score demonstrated good calibration but suboptimal discrimination for predicting thrombosis. The findings support the use of either the ADA or IMPROVE score for thrombosis risk assessment. The applicability of the ADA score to non-COVID-19 populations warrants further research.Clinical Trial Registration: http://www.clinicaltrials.gov . Unique identifier: NCT01583218.

The Effectiveness of the Intermediate and Therapeutic Doses of Enoxaparin in COVID-19 Patients: A Comparative Study of Factor Xa Inhibition.

BACKGROUND: Management of anticoagulant therapy in COVID-19 patients is critical. Low-molecular-weight heparin (LMWH) thromboprophylaxis is already recommended, and anti-Factor Xa (anti-FXa) monitoring has been used to titrate LMWH doses. METHODS: Through a cross-sectional study, we evaluated anti-FXa activity in patients admitted to the ICU, receiving intermediate dose (30, 40, 50 mg, subcutaneously [SC], twice daily) or therapeutic dose (1 mg/kg, SC, Q12h) of enoxaparin to find whether the patients in these two groups achieved anti-FXa levels in the accepted thromboprophylaxis range. RESULTS: The occurrence of deep vein thrombosis was 26% in the therapeutic-dose group and 17% in the intermediate-dose group. D-dimer values were nearly 3.5-fold higher in those who received a therapeutic dose of anticoagulants than in those who received intermediate-dose thromboprophylaxis. Patients in the therapeutic-dose group had significantly higher IL-6 levels (p ≤ 0.001). More than one-third of the patients in the therapeutic-dose group (n = 8; 42.18%) and approximately half of the patients in the intermediate-dose group (n = 12; 52.2%) achieved the target range level of anti-FXa. Patients who received therapeutic doses were more likely to have anti-FXa levels above the expected range (47.4 vs 13% in the intermediate-dose group; p < 0.05). CONCLUSION: Therapeutic dose of enoxaparin in critically ill COVID-19-infected patients did not reduce the incidence of thromboembolic events and, on the other hand, may predispose these patients to increased risk of bleeding by increasing anti-FXa activity above the desired level. Administration of intermediate-dose thromboprophylaxis is suggested to achieve anti-FXa levels in the accepted thromboprophylaxis range.

Central Retinal Vein Occlusion After Discontinuation of Rivaroxaban Therapy in a Young Patient with COVID-19 Pulmonary Embolism: A Case Report.

BACKGROUND We present the report of the first case, to the best of our knowledge, of central retinal vein occlusion (CRVO) that occurred 3 days after anticoagulation discontinuation in a patient with a history of pulmonary embolism in the course of COVID-19. CASE REPORT A previously healthy 38-year-old man was hospitalized in April 2021 with severe COVID-19 pneumonia, complicated by segmental and subsegmental pulmonary embolism. The patient was treated with a concurrent combination of remdesivir, dexamethasone, therapeutic enoxaparin, ceftriaxone, passive oxygen therapy, and convalescent plasma therapy, which led to pulmonary improvement. The treatment with therapeutic enoxaparin (80 mg/0.8 mL twice a day) was continued for 1 month after discharge, followed by 15 mg of rivaroxaban twice a day for 3 weeks and 20 mg of rivaroxaban once a day for 11 weeks. Within 3 days after rivaroxaban discontinuation, the patient experienced a decrease in visual acuity in his right eye, to the level of 5/25. Nonischemic CRVO with cystoid macular edema was diagnosed and an intravitreal injection of ranibizumab was performed. Common identifiable factors contributing to CRVO were excluded, and the treatment with prophylactic enoxaparin was initiated. Two weeks later, macular edema decreased significantly and visual acuity improved to 20/20. The treatment with enoxaparin was discontinued. CONCLUSIONS Rebound hypercoagulability after discontinuation of rivaroxaban therapy can manifest as CRVO in a young patient with a history of COVID-19 pulmonary embolism. It was successfully treated with an intravitreal injection of ranibizumab.

In-hospital Mortality Rates in SARS-CoV-2 Patients Treated with Enoxaparin and Heparin.

OBJECTIVES: This study aimed to investigate in-hospital mortality rates in patients with coronavirus disease (COVID-19) according to enoxaparin and heparin use. METHODS: This retrospective cohort study included 962 patients admitted to two hospitals in Kuwait with a confirmed diagnosis of COVID-19. Cumulative all-cause mortality rate was the primary outcome. RESULTS: A total of 302 patients (males, 196 [64.9%]; mean age, 57.2 ± 14.6 years; mean body mass index, 29.8 ± 6.5 kg/m2) received anticoagulation therapy. Patients receiving anticoagulation treatment tended to have pneumonia (n = 275 [91.1%]) or acute respiratory distress syndrome (n = 106 [35.1%]), and high D-dimer levels (median [interquartile range]: 608 [523;707] ng/mL). The mortality rate in this group was high (n = 63 [20.9%]). Multivariable logistic regression, the Cox proportional hazards, and Kaplan-Meier models revealed that the use of therapeutic anticoagulation agents affected the risk of all-cause cumulative mortality. CONCLUSION: Age, hypertension, pneumonia, therapeutic anticoagulation, and methylprednisolone use were found to be strong predictors of in-hospital mortality. In elderly hypertensive COVID-19 patients on therapeutic anticoagulation were found to have 2.3 times higher risk of in-hospital mortality. All cause in-hospital mortality rate in the therapeutic anticoagulation group was up to 21%.

Low-Molecular-Weight Heparin Resistance and Its Viscoelastic Assessment in Critically Ill COVID-19 Patients.

Critically ill COVID-19 patients present an inflammatory and procoagulant status with a high rate of relevant macro- and microvascular thrombosis. Furthermore, high rates of heparin resistance have been described; yet, individualized anticoagulation by drug monitoring has not been sufficiently researched. We analyzed data from critically ill COVID-19 patients treated at Innsbruck Medical University Hospital with routinely adapted low-molecular-weight heparin (LMWH) doses according to anti-Xa peak levels, and regularly performed ClotPro analyses (a viscoelastic hemostatic whole blood test). A total of 509 anti-Xa peak measurements in 91 patients were categorized as below (<0.008 IU/mL/mg), within (0.008-0-012 IU/mL/mg) or above (> 0.012 IU/mL/mg) expected ranges with respect to the administered LMWH doses. Besides intergroup comparisons, correlations between anti-Xa levels and ClotPro clotting times (CTs) were performed (226 time points in 84 patients). Anti-Xa peak levels remained below the expected range in the majority of performed measurements (63.7%). Corresponding patients presented with higher C-reactive protein and D-dimer but lower antithrombin levels when compared with patients achieving or exceeding the expected range. Consequently, higher enoxaparin doses were applied in the sub-expected anti-Xa range group. Importantly, 47 (51.6%) patients switched between groups during their intensive care unit (ICU) stay. Anti-Xa levels correlated weakly with IN test CT and moderately with Russell's viper venom (RVV) test CT. Critically ill COVID-19 patients present with a high rate of LMWH resistance but with a variable LMWH response during their ICU stay. Therefore, LMWH-anti-Xa monitoring seems inevitable to achieve adequate target ranges. Furthermore, we propose the use of ClotPro's RVV test to assess the coagulation status during LMWH administration, as it correlates well with anti-Xa levels but more holistically reflects the coagulation cascade than anti-Xa activity alone.

Thromboprophylaxis and clinical outcomes in moderate COVID-19 patients: A comparative study.

BACKGROUND: Many thrombotic complications are linked to coronavirus disease 2019 (COVID-19). Antithrombotic treatments are important for prophylaxis against these thrombotic events. OBJECTIVES: This study was designed to compare enoxaparin and rivaroxaban as prophylactic anticoagulants in moderate cases of COVID-19 in terms of efficacy, safety, and clinical outcomes. METHODS: The study involved 124 patients with moderate COVID-19 (pneumonia without hypoxia) divided into two groups. The first group (G1) comprised 66 patients who received enoxaparin subcutaneously at a dose of 0.5 mg/kg every 12 h until discharge from the hospital. The second group (G2) comprised 58 patients who received oral rivaroxaban at a dose of 10 mg once daily until discharge from the hospital. The outcomes evaluated in this study were as follows: intermediate care unit (IMCU) duration, the number of patients transferred from the IMCU to the intensive care unit (ICU), ICU duration, the total length of hospital stay, in-hospital mortality, and thrombotic and bleeding complications. RESULTS: No significant differences in IMCU duration (p = 0.39), ICU duration (p = 0.96), and total length of hospital stay (p = 0.73) were observed between the two groups. The percentage of patients requiring ICU admission after hospitalization was 21.2% in G1 and 22.4% in G2 (p = 0.87). The mortality rate was 12.1% in G1 and 10.3% in G2 (p = 0.76). The proportion of patients who had thrombotic complications was 9.1% in G1 and 12.1% in G2 (p = 0.59). The incidence of mild bleeding was 3% in G1 and 1.7% in G2 (p = 0.64). CONCLUSION: Either enoxaparin or rivaroxaban may be used as thromboprophylaxis agents in managing patients with moderate COVID-19. Either medication has no clear advantage over the other.

Incidence and effects of deep vein thrombosis on the outcome of patients with coronavirus disease 2019 infection.

BACKGROUND: Deep vein thrombosis (DVT) has been reported to occur at different rates in patients with coronavirus disease 2019 (COVID-19). Limited data exist regarding comparisons with non-COVID-19 patients with similar characteristics. Our objective was to compare the rates of DVT in patients with and without COVID-19 and to determine the effect of DVT on the outcomes. METHODS: We performed a retrospective, observational cohort study at a single-institution, level 1 trauma center comparing patients with and without COVID-19. The 573 non-COVID-19 patients (age, 61 ± 17 years; 44.9% male) had been treated from March 20, 2019 to June 30, 2019, and the 213 COVID-19 patients (age, 61 ± 16 years; 61.0% male) had been treated during the same interval in 2020. Standard prophylactic anticoagulation therapy consisted of 5000 U of heparin three times daily for the medical patients without COVID-19 who were not in the intensive care unit (ICU). The ICU, surgical, and trauma patients without COVID-19 had received 40 mg of enoxaparin daily (not adjusted to weight). The patients with COVID-19 had also received enoxaparin 40 mg daily (also not adjusted to weight), regardless of whether treated in the ICU. The two primary outcomes were the rate of deep vein thrombosis (DVT) in the COVID-19 group vs that in the historic control and the effect of DVT on mortality. The subgroup analyses included patients with adult respiratory distress syndrome (ARDS), pulmonary embolism (PE), and intensive care unit patients (ICU). RESULTS: The rate of DVT and PE for the non-COVID-19 patients was 12.4% (71 of 573) and 3.3% (19 of 573) compared with 33.8% (72 of 213) and 7.0% (15 of 213) for the COVID-19 patients, respectively. Unprovoked PE had developed in 10 of 15 COVID-19 patients (66.7%) compared with 8 of 497 non-COVID-19 patients (1.6%). The 60 COVID-19 patients with ARDS had had an incidence of DVT of 46.7% (n = 28). In contrast, the incidence of DVT for the 153 non-COVID-19 patients with ARDS was 28.8% (n = 44; P = .01). The COVID-19 patients requiring the ICU had had an increased rate of DVT (39 of 90; 43.3%) compared with the non-COVID-19 patients (33 of 123; 33.3%; P = .01). The risk factors for mortality included age, DVT, multiple organ failure syndrome, and prolonged ventilatory support with the following odd ratios: 1.030 (95% confidence interval [CI], 1.002-1.058), 2.847 (95% CI, 1.356-5.5979), 4.438 (95% CI, 1.973-9.985), and 5.321 (95% CI, 1.973-14.082), respectively. CONCLUSIONS: The incidence of DVT for COVID-19 patients receiving standard-dose prophylactic anticoagulation that was not weight adjusted was high, especially for ICU patients. DVT is one of the factors contributing to increased mortality. These results suggest a reevaluation is necessary of the present standard-dose thromboprophylaxis for patients with COVID-19.

Anti-Inflammatory Effects and Decreased Formation of Neutrophil Extracellular Traps by Enoxaparin in COVID-19 Patients.

Neutrophil Extracellular Traps (NETs) are a contributing factor of vascular thrombosis and alveolar damage in COVID-19 patients. As enoxaparin is currently used to inhibit vascular thrombosis, this study aimed to investigate whether enoxaparin also reduced inflammation and NETs in COVID-19 patients. Patients with COVID-19 infection were classified into three groups: mild, moderate, and severe (n = 10 for all groups). Plasma was collected from patients and healthy donors (n = 10). Neutrophils isolated from healthy controls were incubated with COVID-19 or healthy plasma, and with or without enoxaparin pretreatment in vitro. Neutrophils and plasma isolated from patients treated with enoxaparin were also investigated. The levels of inflammatory cytokines and NET products such as dsDNA, NE, MPO-DNA and Histone-DNA complexes in plasma and supernatants were measured using immunofluorescence staining and ELISA kits. The expression of inflammatory signaling genes by neutrophils (RELA, SYK, ERK and PKC) was measured using real-time qPCR. The levels of NET products were elevated in the plasma of COVID-19 patients, particularly in the severe group (p < 0.01). Moreover, plasma from the severe group enhanced NET formation (p < 0.01) from neutrophils in vitro. Enoxaparin pretreatment in vitro decreased plasma-induced NETs in a dose-dependent manner and down-regulated the expression of inflammatory genes (p < 0.05). Patients treated with prophylactic enoxaparin showed lower inflammatory cytokine levels and expression of inflammatory genes (p < 0.05). Increased NETs were associated with the severity of COVID-19 infection, particularly in patients with severe pneumonia, and could be used as biomarkers to assess disease severity. Enoxaparin pretreatment inhibited NETs and reduced the expression of inflammatory cytokines, and these effects mostly persisted in patients treated with prophylactic enoxaparin.

Retroperitoneal hematoma in COVID-19 patients - case series.

COVID-19 patients, particularly those with severe pulmonary involvement, are at an increased thromboembolic risk related, among various causes, to the cytokine storm and excessive activation of the coagulation cascade and platelets. Different intensity of anticoagulation for them is proposed, mainly with low molecular weight heparins (LMWHs); in a confirmed pulmonary embolism (PE) the therapeutic dose of LMWH is routinely used. Some authors suggest that hemorrhagic complications in COVID-19 patients are rare. At the same time, one can find reports on internal bleeding, including retroperitoneal hematoma (RPH) and other abdominal hematomas. CASE REPORTS: The authors describe 5 cases (3 of those aged more than 80 years) with giant RPHs and with moderate/severe COVID-19 pneumonia, treated before RPH diagnosis with different enoxaparin doses. The therapeutic dose was given to the male with verified PE limited to the segmental/subsegmental pulmonary arteries and initially to the female in whom echocardiography was strongly suggestive of PE, yet this diagnosis was excluded on CT angiography. In one patient, the enoxaparin dose was escalated from 40 mg bd to 60 mg bd after the D-dimer increase. Two patients had bleeding complications despite the enoxaparin dose restricted to 40 mg/daily or bd. Two males had a coexistent psoas hematoma while in only one female there was a coexistent femoral hematoma. RPHs occurred between day 4 and 14 of hospitalization and all were treated conservatively. Three patients who died were particularly charged, so their deaths were not merely directly associated with RPH, which was closely analyzed in one autopsy performed. The authors underline that the choice of anticoagulation intensity in patients with COVID-19 pneumonia without venous thromboembolism seems sometimes difficult but recent publications indicate the low prophylactic enoxaparin dose as an optimal option. Anticoagulation dose escalation based only on the D-dimer level may not be appropriate for certain patients; moreover, the D-dimer increase is commonly observed during internal bleeding.

Advanced cell therapy with low tissue factor loaded product NestaCell® does not confer thrombogenic risk for critically ill COVID-19 heparin-treated patients.

Since the COVID-19 pandemic started, mesenchymal stromal cells (MSC) appeared as a therapeutic option to reduce the over-activated inflammatory response and promote recovery of lung damage. Most clinical studies use intravenous injection for MSC delivery, raising several concerns of thrombogenic risk due to MSC procoagulant activity (PCA) linked to the expression of tissue factor (TF/CD142). This is the first study that demonstrated procoagulant activity of TF+ human immature dental pulp stromal cells (hIDPSC, NestaCell® product) with the percentage of TF+ cells varied from 0.2% to 63.9% in plasma of healthy donors and COVID-19 heparin-treated patients. Thrombogenic risk of TF+ hIDPSCs was evaluated by rotational thromboelastometry (in vitro) and in critically ill COVID-19 patients (clinical trial). We showed that the thromboelastography is not enough to predict the risk of TF+ MSC therapies. Using TF-negative HUVEC cells, we demonstrated that TF is not a unique factor responsible for the cell's procoagulant activity. However, heparin treatment minimizes MSC procoagulant (in vitro). We also showed that the intravenous infusion of hIDPSCs with prophylactic enoxaparin administration in moderate to critically ill COVID-19 patients did not change the values of D-dimer, neither in the PT and PTT times. Our COVID-19 clinical study measured and selected the therapeutic cells with low TF (less than 25% of TF+ hIDPSCs). Our data indicate that the concomitant administration of enoxaparin and low TF-loaded is safe even for critically ill COVID-19 patients.

Anticoagulation in Patients With COVID-19: JACC Review Topic of the Week.

Clinical, laboratory, and autopsy findings support an association between coronavirus disease-2019 (COVID-19) and thromboembolic disease. Acute COVID-19 infection is characterized by mononuclear cell reactivity and pan-endothelialitis, contributing to a high incidence of thrombosis in large and small blood vessels, both arterial and venous. Observational studies and randomized trials have investigated whether full-dose anticoagulation may improve outcomes compared with prophylactic dose heparin. Although no benefit for therapeutic heparin has been found in patients who are critically ill hospitalized with COVID-19, some studies support a possible role for therapeutic anticoagulation in patients not yet requiring intensive care unit support. We summarize the pathology, rationale, and current evidence for use of anticoagulation in patients with COVID-19 and describe the main design elements of the ongoing FREEDOM COVID-19 Anticoagulation trial, in which 3,600 hospitalized patients with COVID-19 not requiring intensive care unit level of care are being randomized to prophylactic-dose enoxaparin vs therapeutic-dose enoxaparin vs therapeutic-dose apixaban. (FREEDOM COVID-19 Anticoagulation Strategy [FREEDOM COVID]; NCT04512079).

Case Report: Home-based Management of Severe COVID-19 with Low-dose Tofacitinib.

Human lives and nations' economies have been adversely affected worldwide by the COVID-19 pandemic. The hyperinflammatory state associated with the disease may be related to mortality. Systemic glucocorticoid is the first-line therapy for cytokine storm. Various immunomodulatory drugs such as tocilizumab and baricitinib have been used in those not responding to glucocorticoid monotherapy. Amid the peak crisis of COVID-19 in India, there was an extreme paucity of medications, oxygen, and hospital beds. We describe three patients with COVID-19 who received low-dose tofacitinib (an oral Janus kinase inhibitor) in addition to moderate-dose glucocorticoid. These patients were treated at their homes, as the hospitals were short of beds. Rapid reduction in hypoxemia along with gradual resolution of other signs of the disease were observed. The results are reassuring regarding the feasibility of managing of severe COVID-19 outside the hospital setting when healthcare resources are overwhelmed by pandemic-related caseload.

Enoxaparin for thromboprophylaxis in hospitalized COVID-19 patients: The X-COVID-19 Randomized Trial.

BACKGROUND: It is uncertain whether higher doses of anticoagulants than recommended for thromboprophylaxis are necessary in COVID-19 patients hospitalized in general wards METHODS: This is a multicentre, open-label, randomized trial performed in 9 Italian centres, comparing 40 mg b.i.d. versus 40 mg o.d. enoxaparin in COVID-19 patients, between April 30 2020 and April 25 2021. Primary efficacy outcome was in-hospital incidence of venous thromboembolism (VTE): asymptomatic or symptomatic proximal deep vein thrombosis (DVT) diagnosed by serial compression ultrasonography (CUS), and/or symptomatic pulmonary embolism (PE) diagnosed by computed tomography angiography (CTA). Secondary endpoints included each individual component of the primary efficacy outcome and a composite of death, VTE, mechanical ventilation, stroke, myocardial infarction, admission to ICU. Safety outcomes included major bleeding. RESULTS: The study was interrupted prematurely due to slow recruitment. We included 183 (96%) of the 189 enrolled patients in the primary analysis (91 in b.i.d., 92 in o.d.). Primary efficacy outcome occurred in 6 patients (6.5%, 0 DVT, 6 PE) in the o.d. group and 0 in the b.id. group (ARR 6.5, 95% CI: 1.5-11.6). The absence of concomitant DVT and imaging characteristics suggests that most pulmonary artery occlusions were actually caused by local thrombi rather than PE. Statistically nonsignificant differences in secondary and safety endpoints were observed, with two major bleeding events in each arm. CONCLUSIONS: No DVT developed in COVID-19 patients hospitalized in general wards, independently of enoxaparin dosing used for thromboprophylaxis. Pulmonary artery occlusions developed only in the o.d. group. Our trial is underpowered and with few events.

Comparison of demographic and clinical characteristics of hospitalized COVID-19 patients with severe/critical illness in the first wave versus the second wave.

Due to current advances and growing experience in the management of coronavirus Disease 2019 (COVID-19), the outcome of COVID-19 patients with severe/critical illness would be expected to be better in the second wave compared with the first wave. As our hospitalization criteria changed in the second wave, we aimed to investigate whether a favorable outcome occurred in hospitalized COVID-19 patients with only severe/critical illness. Among 642 laboratory-confirmed hospitalized COVID-19 patients in the first wave and 1121 in the second wave, those who met World Health Organization (WHO) definitions for severe or critical illness on admission or during follow-up were surveyed. Data on demographics, comorbidities, C-reactive protein (CRP) levels on admission, and outcomes were obtained from an electronic hospital database. Univariate analysis was performed to compare the characteristics of patients in the first and second waves. There were 228 (35.5%) patients with severe/critical illness in the first wave and 681 (60.7%) in the second wave. Both groups were similar in terms of age, gender, and comorbidities, other than chronic kidney disease. Median serum CRP levels were significantly higher in patients in the second wave compared with those in the first wave [109 mg/L (interquartile range [IQR]: 65-157) vs. 87 mg/L (IQR: 39-140); p < 0.001]. However, intensive care unit admission and mortality rates were similar among the waves. Even though a lower mortality rate in the second wave has been reported in previous studies, including all hospitalized COVID-19 patients, we found similar demographics and outcomes among hospitalized COVID-19 patients with severe/critical illness in the first and second wave.

Abelacimab for Prevention of Venous Thromboembolism.

BACKGROUND: The role of factor XI in the pathogenesis of postoperative venous thromboembolism is uncertain. Abelacimab is a monoclonal antibody that binds to factor XI and locks it in the zymogen (inactive precursor) conformation. METHODS: In this open-label, parallel-group trial, we randomly assigned 412 patients who were undergoing total knee arthroplasty to receive one of three regimens of abelacimab (30 mg, 75 mg, or 150 mg) administered postoperatively in a single intravenous dose or to receive 40 mg of enoxaparin administered subcutaneously once daily. The primary efficacy outcome was venous thromboembolism, detected by mandatory venography of the leg involved in the operation or objective confirmation of symptomatic events. The principal safety outcome was a composite of major or clinically relevant nonmajor bleeding up to 30 days after surgery. RESULTS: Venous thromboembolism occurred in 13 of 102 patients (13%) in the 30-mg abelacimab group, 5 of 99 patients (5%) in the 75-mg abelacimab group, and 4 of 98 patients (4%) in the 150-mg abelacimab group, as compared with 22 of 101 patients (22%) in the enoxaparin group. The 30-mg abelacimab regimen was noninferior to enoxaparin, and the 75-mg and 150-mg abelacimab regimens were superior to enoxaparin (P<0.001). Bleeding occurred in 2%, 2%, and none of the patients in the 30-mg, 75-mg, and 150-mg abelacimab groups, respectively, and in none of the patients in the enoxaparin group. CONCLUSIONS: This trial showed that factor XI is important for the development of postoperative venous thromboembolism. Factor XI inhibition with a single intravenous dose of abelacimab after total knee arthroplasty was effective for the prevention of venous thromboembolism and was associated with a low risk of bleeding. (Funded by Anthos Therapeutics; ANT-005 TKA EudraCT number, 2019-003756-37.).

Acetylsalicylic Acid Compared with Enoxaparin for the Prevention of Thrombosis and Mechanical Ventilation in COVID-19 Patients: A Retrospective Cohort Study.

BACKGROUND AND OBJECTIVE: Low-dose acetylsalicylic acid (ASA, aspirin) is a well-known and frequently studied drug for primary and secondary prevention of disease due to its anti-inflammatory and coagulopathic effects. COVID-19 complications are attributed to the role of thrombo-inflammation. Studies regarding the use of low-dose ASA in COVID-19 are limited. For this reason, we propose that the use of low-dose ASA may have protective effects in COVID-19-related thromboembolism and lung injury. This study was conducted to assess the efficacy of low-dose ASA compared with enoxaparin, an anticoagulant, for the prevention of thrombosis and mechanical ventilation. METHODS: We conducted a retrospective cohort study on COVID-19-confirmed hospitalized patients at the Mansoura University Quarantine Hospital, outpatients, and home-isolated patients from September to December 2020 in Mansoura governorate, Egypt. Binary logistic regression analysis was used to assess the effect of ASA compared with enoxaparin on thromboembolism, and mechanical ventilation needs. RESULTS: This study included 225 COVID-19 patients. Use of ASA-only (81-162 mg orally daily) was significantly associated with reduced thromboembolism (OR 0.163, p = 0.020), but both low-dose ASA and enoxaparin, and enoxaparin-only (0.5 mg/kg subcutaneously (SC) daily as prophylactic dose or 1 mg/kg SC every 12 hours as therapeutic dose) were more protective (odds ratio [OR] 0.010, OR 0.071, respectively, p < 0.001). Neither ASA-only nor enoxaparin-only were associated with a reduction in mechanical ventilation needs. Concomitant use of low-dose ASA and enoxaparin was associated with reduced mechanical ventilation (OR 0.032, 95% CI 0.004-0.226, p = 0.001). CONCLUSIONS: Low-dose ASA-only use may reduce the incidence of COVID-19-associated thromboembolism, but the reduction may be less than that of enoxaparin-only, and both ASA and enoxaparin. Concomitant use of ASA and enoxaparin demonstrates promising results with regard to the reduction of thrombotic events, and mechanical ventilation needs.