Impact of atrial fibrillation and anticoagulation on the risk of death, thromboembolic disease and bleeding in patients with COVID-19: the ACO-VID Registry.

OBJECTIVE: To describe the clinical profile, risk of complications and impact of anticoagulation in COVID-19 hospitalized patients, according to the presence of atrial fibrillation (AF). METHODS: Multicenter, retrospective, and observational study that consecutively included patients >55 years admitted with COVID-19 from March to October 2020. In AF patients, anticoagulation was chosen based on clinicians' judgment. Patients were followed-up for 90 days. RESULTS: A total of 646 patients were included, of whom 75.2% had AF. Overall, mean age was 75 ± 9.1 years and 62.4% were male. Patients with AF were older and had more comorbidities. The most common anticoagulants used during hospitalization in patients with AF were edoxaban (47.9%), low molecular weight heparin (27.0%), and dabigatran (11.7%) and among patients without AF, these numbers were 0%, 93.8% and 0%. Overall, during the study period (68 ± 3 days), 15.2% of patients died, 8.2% of patients presented a major bleeding and 0.9% had a stroke/systemic embolism. During hospitalization, patients with AF had a higher risk of major bleeding (11.3% vs 0.7%; p < .01), COVID-19-related deaths (18.0% vs 4.5%; p = .02), and all-cause deaths (20.6% vs 5.6%; p = .02). Age (HR 1.5; 95% CI 1.0-2.3) and elevated transaminases (HR 3.5; 95% CI 2.0-6.1) were independently associated with all-cause mortality. AF was independently associated with major bleeding (HR 2.2; 95% CI 1.1-5.3). CONCLUSIONS: Among patients hospitalized with COVID-19, patients with AF were older, had more comorbidities and had a higher risk of major bleeding. Age and elevated transaminases during hospitalization, but not AF nor anticoagulant treatment increased the risk of all-cause death.

[COVID 19 - Hospital Admission in the First and Second Wave in Germany]. / COVID 19 ­ Hospitalisierung in der ersten und zweiten Welle.

PURPOSE: We analyzed patients' characteristics and hospital admission in Germany's first and second COVID 19 wave. METHODS: We include all patients hospitalized with the proven diagnosis COVID 19 admitted to the HELIOS Hospital Krefeld, Germany, in the first wave (n = 84; from 11.03.2020-30.06.2020) and the second wave (n = 344; from 01.07.2020-31.01.2021). RESULTS: Patients' age, gender and comorbidities were similar with the exception of venous thrombosis in medical history which was more frequent in the first wave (6 % vs 0.3 %, p = p = 0,001). At admission, there were no differences in the results of the initial lab values (c-reactive protein, leucocytes) and blood gas analyses between both groups. Treatment differed in the application of dexamethasone and anticoagulation. In the first wave, nobody received dexamethasone. However, this changed to 52.6 % of patients in the second wave for a mean length of 3.6 ±â€Š4.1 days. Anticoagulation with double standard prophylaxis (2 × 40 mg low molecular heparin, subcutaneous) was applied in 7.1 % of patients in the first wave but 30.2 % (p = 0.002) in the second wave. In the first wave more thromboembolic events were diagnosed after admission (19.0 % vs 7.0 %, p = 0.001). In-hospital death was 26.2 % in the first wave and 15.4 % in the second wave (p = 0.0234). Most deaths were attributed to acute respiratory distress syndrome (ARDS). CONCLUSION: Patients' characteristics did not vary in Germany's first and second COVID 19 wave, but anticoagulation and dexamethasone were applied more frequently in the second wave. In addition, there were fewer thromboembolic complications in the second wave.

Extracardiac Prothrombotic Effects of COVID-19.

COVID-19 infection triggers a heightened inflammatory response which in turn, increases thrombosis and thromboembolism. Microvascular thrombosis has been detected in various tissue beds which may account for some of the multi-system organ dysfunction associated with COVID-19. Additional research is needed to understand which prophylactic and therapeutic drug regimens are best for the prevention and treatment of thrombotic complications of COVID-19.

The Impact of Prior Antithrombotic use on Thromboembolic Events in Patients with Cardiovascular Disease and Severe COVID-19 Infection.

OBJECTIVE: Our objective in this study was to determine the predictive factors of thromboembolic complications in patients with previous heart disease and severe covid-19 infection and the impact of previous use of antithrombotics on protection against these complications. METHODS: We conducted a single-center retrospective study of 158 patients with heart disease admitted to an intensive care unit for severe SARS-COV-2 infection. In order to determine the predictive factors, we used logistic regression analysis. RESULTS: Out of 158 patients, 22 were complicated by a thrombo-embolic event (13.9%), mean age of our population 64.03 (SD = 15.27), with a male predominance of 98 (62%). For the predictive factors of thromboembolic complications, and after multivariate analysis, we find the short duration of hospitalization (OR = 0.92; 95%CI (0.863-0.983), P = .014, previous use of antithrombotic drugs ((OR = 0.288, 95%CI (0.091-0.911), P = .034 for antiplatelet agents) and (OR = 0.322, 95% CI (0, 131-0.851), P = .021) for anticoagulants) as protective factors, and admission thrombocytosis as a risk factor (OR = 4.58, 95%CI (1.2-10.627), P = .021). D-dimer was not detected as a risk factor, and this can be explained by the characteristics of our population. Although prior use of antithrombotic drugs protects against thromboembolic complications during severe infection, there was no benefit in mortality. CONCLUSION: Prior use of antithrombotic drugs is a protective factor against thromboembolic complications in patients with a history of heart disease but without effect on mortality.

Anticoagulation in COVID-19 patients - An updated systematic review and meta-analysis.

BACKGROUND: Thromboembolic events are common complications of COVID-19. Clinical study results on safety and efficacy of anticoagulation in COVID-19 are controversial. MATERIAL AND METHODS: This report updates our systematic review and random-effects meta-analysis on randomized controlled trials (RCTs) comparing standard prophylactic anticoagulation and intermediate or therapeutic anticoagulation in COVID-19 patients. We searched eligible studies for the update up to 4 February 2022 by weekly monitoring of RCTs in the Cochrane COVID-19 Study Register. Certainty of evidence was assessed using GRADE (Grading of Recommendations Assessment, Development and Evaluation). RESULTS: For this update we included five new trials; a total of 13 RCTs with 7364 patients. Certainty of evidence was very low to low. We are uncertain whether low-dose prophylactic anticoagulation is favoured over placebo or no anticoagulation in the outpatient- or post-discharge-setting. In hospitalized patients with moderate and severe COVID-19, intermediate-dose anticoagulation may have little or no effect on thrombotic events or death (RR 1.03, 95 % CI 0.86-1.24), but may increase severe bleeding non-significantly (RR 1.48, 95 % CI 0.53-4.15). Therapeutic-dose anticoagulation may decrease thrombotic events or deaths in hospitalized patients with moderate COVID-19 (RR 0.64, 95 % CI 0.38-1.07; fixed-effect model RR 0.72, 95 % CI 0.57-0.91), but may have little or no effect in patients with severe disease (RR 0.98, 95 % CI 0.86-1.12). With therapeutic-dose anticoagulation, the risk of major bleeding may increase regardless of COVID-19 severity (RR 1.78, 95 % CI 1.15-2.74). CONCLUSIONS: Hospitalized, moderately ill COVID-19 patients may benefit from therapeutic-dose anticoagulation, while critically ill patients may not. Risk of major bleeding must be considered.

Real-World Analysis of Thromboembolic Events and Mortality of COVID-19 Outpatients in the United States.

Limited data are available on thromboembolic events (TEEs) and mortality in outpatients with coronavirus disease 2019 (COVID-19). This retrospective, observational cohort study identified non-hospitalized COVID-19 outpatients (01/21/2020-01/07/2021) using de-identified Optum® COVID-19 Electronic Health Records data. Patient characteristics, occurrence of TEEs, all-cause mortality, and anticoagulant or thrombolytic medication use were evaluated. Of 1,246,067 patients with COVID-19 diagnosis, 141 471 met entry criteria. Mean (standard deviation [SD]) age was 46.1 (17.2) years, 56.8% were female, 72.9% Caucasian, 11.2% African American, and 11.1% Hispanic. Comorbidity burden was low (mean [SD] Quan-Charlson comorbidity index score of 0.43 [1.10]); however, of those with body mass index data, half were obese. During the follow-up period, a TEE occurred in 1.4%, with the proportion of patients with ischemic stroke, myocardial infarction, deep vein thrombosis, and pulmonary embolism being similar (approximately 0.4% each). All-cause mortality was 0.7%. Medications included corticosteroids (13.7%), anticoagulants (4.9%), and antiplatelets (2.9%). Overall, in this large cohort analysis, certain demographic and clinical characteristics of patients who experienced TEEs were identified and may help guide management decisions and future clinical trials for COVID-19 outpatients.

COVID-19 associated coagulopathy and thrombosis in cancer.

Cancer patients are at risk for a more severe COVID-19 infection as well as an adverse outcome of such infection. This may be caused by the cancer itself (e.g haematological malignancies and lung cancer) or due to immune suppression caused by anti-cancer treatment. Severe COVID-19 infections are often complicated by a coagulopathy that clinically results in a high incidence of venous thromboembolic disease. Cancer itself is associated with a hypercoagulable state and a markedly increased incidence of thromboembolic complications, hence the combination of cancer and COVID-19 may amplify this risk. COVID-19 vaccination seems safe and effective in most cancer patients although adapted and bespoke vaccination schemes may increase the seroconversion rate and immune response in selected patients. Specific management strategies to improve outcomes of cancer patients in COVID-19 (e.g. higher intensity antithrombotic prophylaxis) are lacking and should be evaluated in clinical studies simultaneously focusing on efficacy and safety.

Four-factor prothrombin complex concentrate plus andexanet alfa for reversal of factor Xa inhibitor-associated bleeding: Case series.

PURPOSE: To manage factor Xa (FXa) inhibitor-associated bleeding, andexanet alfa or 4-factor prothrombin concentrate (4F-PCC) has been used to restore hemostasis. However, literature on the outcomes for patients who received both andexanet alfa and 4F-PCC is limited. SUMMARY: We report a case series of 5 patients who received andexanet alfa plus 4F-PCC for reversal of FXa inhibitor-associated bleeding. Patients were included in this case series if they received both andexanet alfa and 4F-PCC for reversal of FXa inhibitor-associated bleeding. They were followed to either discharge or death, and in-hospital complications related to concurrent use of andexanet alfa and 4F-PCC were documented. We report an incidence of thromboembolism of 40% (2 of 5 cases) and an in-hospital mortality rate of 60% (3 of 5 cases). Taking these cases together with those in the existing literature, we found a total of 23 reported cases of safety outcomes with andexanet alfa plus 4F-PCC. The overall incidence of thromboembolism was 35% (8 of 23 cases). CONCLUSION: This case series adds to the limited literature describing the outcomes for patients receiving andexanet alfa plus 4F-PCC. We encourage other institutions to report safety data on administering both agents.

Anticoagulant Treatment Regimens in Patients With Covid-19: A Meta-Analysis.

Coronavirus disease 2019 (COVID-19) is associated with a hypercoagulable state. It has been hypothesized that higher-dose anticoagulation, including therapeutic-dose and intermediate-dose anticoagulation, is superior to prophylactic-dose anticoagulation in the treatment of COVID-19. This meta-analysis evaluated the efficacy and safety of higher-dose anticoagulation compared with prophylactic-dose anticoagulation in patients with COVID-19. Ten randomized controlled open-label trials with a total of 5,753 patients were included. The risk of death and net adverse clinical events (including death, thromboembolic events, and major bleeding) were similar between higher-dose and prophylactic-dose anticoagulation (risk ratio (RR) 0.96, 95% CI, 0.79-1.16, P = 0.66 and RR 0.87, 95% CI, 0.73-1.03, P = 0.11, respectively). Higher-dose anticoagulation, compared with prophylactic-dose anticoagulation, decreased the risk of thromboembolic events (RR 0.63, 95% CI, 0.47-0.84, P = 0.002) but increased the risk of major bleeding (RR 1.76, 95% CI, 1.19-2.62, P = 0.005). The risk of death showed no statistically significant difference between higher-dose anticoagulation and prophylactic-dose anticoagulation in noncritically ill patients (RR 0.87, 95% CI, 0.50-1.52, P = 0.62) and in critically ill patients with COVID-19 (RR 1.04, 95% CI, 0.93-1.17, P = 0.5). The risk of death was similar between therapeutic-dose vs. prophylactic-dose anticoagulation (RR 0.92, 95% CI 0.69-1.21, P = 0.54) and between intermediate-dose vs. prophylactic-dose anticoagulation (RR 1.01, 95% CI 0.63-1.61, P = 0.98). In patients with markedly increased d-dimer levels, higher-dose anticoagulation was also not associated with a decreased risk of death as compared with prophylactic-dose anticoagulation (RR 0.86, 95% CI, 0.64-1.16, P = 0.34). Without any clear evidence of survival benefit, these findings do not support the routine use of therapeutic-dose or intermediate-dose anticoagulation in critically or noncritically ill patients with COVID-19.

Thromboembolic Rates Are Similar Between Intensive Care Unit and Nonintensive Care Unit Hospitalized Patients With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Retrospective Cohort Study.

High rates of thromboembolic events have been described in intensive care unit (ICU) patients. Data regarding thromboembolic events in all hospitalized patients has been less frequently reported, raising concerns that thromboembolic events in non-ICU may be underrecognized. In addition, optimal anticoagulation type and dose is still unsettled at this time. This is a retrospective cohort study of 159 hospitalized patients with coronavirus disease 2019 (COVID-19) pneumonia during a 9-month period to determine an association between the frequency of thromboembolic rates and hospitalized patients with COVID-19. Secondary outcomes sought to investigate association of thromboembolic events with relation to place of admission, risk factors, anticoagulation, mortality, hospital length of stay, and discharge disposition. Among the cohort of 159 hospitalized patients who met criteria, 16 (10%) were diagnosed with a thromboembolic event. There were a total of 18 thromboembolic events with 12 venous and 6 arterial. Admission to the ICU was not associated with a higher frequency of thromboembolic events compared with non-ICU patients (37.5% vs 62.5%), p = .71. Patients with a thromboembolic event had a significantly higher mortality compared with those with no thromboembolic event (37.5% vs 13.3%), p = .012. Patients hospitalized with COVID-19 have increased rates of thromboembolic events, both venous and arterial, which contribute to a significant increase in mortality. However, the frequency of thromboembolism in patients admitted to the ICU was similar to events in non-ICU patients. We hope to increase awareness of the increased risk of hypercoagulability in all hospitalized patients with COVID-19 including non-ICU patients.

Heparin and Derivatives for Advanced Cell Therapies.

Heparin and its derivatives are saving thousands of human lives annually, by successfully preventing and treating thromboembolic events. Although the mode of action during anticoagulation is well studied, their influence on cell behavior is not fully understood as is the risk of bleeding and other side effects. New applications in regenerative medicine have evolved supporting production of cell-based therapeutics or as a substrate for creating functionalized matrices in biotechnology. The currently resurgent interest in heparins is related to the expected combined anti-inflammatory, anti-thrombotic and anti-viral action against COVID-19. Based on a concise summary of key biochemical and clinical data, this review summarizes the impact for manufacturing and application of cell therapeutics and highlights the need for discriminating the different heparins.

Association between warfarin and COVID-19-related outcomes compared with direct oral anticoagulants: population-based cohort study.

BACKGROUND: Thromboembolism has been reported as a consequence of severe COVID-19. Although warfarin is a commonly used anticoagulant, it acts by antagonising vitamin K, which is low in patients with severe COVID-19. To date, the clinical evidence on the impact of regular use of warfarin on COVID-19-related thromboembolism is lacking. METHODS: On behalf of NHS England, we conducted a population-based cohort study investigating the association between warfarin and COVID-19 outcomes compared with direct oral anticoagulants (DOACs). We used the OpenSAFELY platform to analyse primary care data and pseudonymously linked SARS-CoV-2 antigen testing data, hospital admissions and death records from England. We used Cox regression to estimate hazard ratios (HRs) for COVID-19-related outcomes comparing warfarin with DOACs in people with non-valvular atrial fibrillation. We also conducted negative control outcome analyses (being tested for SARS-CoV-2 and non-COVID-19 death) to assess the potential impact of confounding. RESULTS: A total of 92,339 warfarin users and 280,407 DOAC users were included. We observed a lower risk of all outcomes associated with warfarin versus DOACs [testing positive for SARS-CoV-2, HR 0.73 (95% CI 0.68-0.79); COVID-19-related hospital admission, HR 0.75 (95% CI 0.68-0.83); COVID-19-related deaths, HR 0.74 (95% CI 0.66-0.83)]. A lower risk of negative control outcomes associated with warfarin versus DOACs was also observed [being tested for SARS-CoV-2, HR 0.80 (95% CI 0.79-0.81); non-COVID-19 deaths, HR 0.79 (95% CI 0.76-0.83)]. CONCLUSIONS: Overall, this study shows no evidence of harmful effects of warfarin on severe COVID-19 disease.

Combined anticoagulant and antiplatelet therapy is associated with an improved outcome in hospitalised patients with COVID-19: a propensity matched cohort study.

BACKGROUND: COVID-19 is a respiratory disease that results in a prothrombotic state manifesting as thrombotic, microthrombotic and thromboembolic events. As a result, several antithrombotic modalities have been implicated in the treatment of this disease. This study aimed to identify if therapeutic anticoagulation (TAC) or concurrent use of antiplatelet and anticoagulants was associated with an improved outcome in this patient population. METHODS: A retrospective observational cohort study of adult patients admitted to a single university hospital for COVID-19 infection was performed. The primary outcome was a composite of in-hospital mortality, intensive care unit (ICU) admission or the need for mechanical ventilation. The secondary outcomes were each of the components of the primary outcome, in-hospital mortality, ICU admission, or the need for mechanical ventilation. RESULTS: 242 patients were included in the study and divided into four subgroups: Therapeutic anticoagulation (TAC), prophylactic anticoagulation+antiplatelet (PACAP), TAC+antiplatelet (TACAP) and prophylactic anticoagulation (PAC) which was the reference for comparison. Multivariable Cox regression analysis and propensity matching were done and showed when compared with PAC, TACAP and TAC were associated with less in-hospital all-cause mortality with an adjusted HR (aHR) of 0.113 (95% CI 0.028 to 0.449) and 0.126 (95% CI 0.028 to 0.528), respectively. The number needed to treat in both subgroups was 11. Furthermore, PACAP was associated with a reduced risk of invasive mechanical ventilation with an aHR of 0.07 (95% CI 0.014 to 0.351). However, the was no statistically significant difference in the occurrence of major or minor bleeds, ICU admission or the composite outcome of in-hospital mortality, ICU admission or the need for mechanical ventilation. CONCLUSION: The use of combined anticoagulant and antiplatelet agents or TAC alone in hospitalised patients with COVID-19 was associated with a better outcome in comparison to PAC alone without an increase in the risk of major and minor bleeds. Sufficiently powered randomised controlled trials are needed to further evaluate the safety and efficacy of combining antiplatelet and anticoagulants agents or using TAC in the management of patients with COVID-19 infection.

Pre-medication with oral anticoagulants is associated with better outcomes in a large multinational COVID-19 cohort with cardiovascular comorbidities.

AIMS: Coagulopathy and venous thromboembolism are common findings in coronavirus disease 2019 (COVID-19) and are associated with poor outcome. Timely initiation of anticoagulation after hospital admission was shown to be beneficial. In this study we aim to examine the association of pre-existing oral anticoagulation (OAC) with outcome among a cohort of SARS-CoV-2 infected patients. METHODS AND RESULTS: We analysed the data from the large multi-national Lean European Open Survey on SARS-CoV-2 infected patients (LEOSS) from March to August 2020. Patients with SARS-CoV-2 infection were eligible for inclusion. We retrospectively analysed the association of pre-existing OAC with all-cause mortality. Secondary outcome measures included COVID-19-related mortality, recovery and composite endpoints combining death and/or thrombotic event and death and/or bleeding event. We restricted bleeding events to intracerebral bleeding in this analysis to ensure clinical relevance and to limit reporting errors. A total of 1 433 SARS-CoV-2 infected patients were analysed, while 334 patients (23.3%) had an existing premedication with OAC and 1 099 patients (79.7%) had no OAC. After risk adjustment for comorbidities, pre-existing OAC showed a protective influence on the endpoint death (OR 0.62, P = 0.013) as well as the secondary endpoints COVID-19-related death (OR 0.64, P = 0.023) and non-recovery (OR 0.66, P = 0.014). The combined endpoint death or thrombotic event tended to be less frequent in patients on OAC (OR 0.71, P = 0.056). CONCLUSIONS: Pre-existing OAC is protective in COVID-19, irrespective of anticoagulation regime during hospital stay and independent of the stage and course of disease.

Viscoelastic testing reveals normalization of the coagulation profile 12 weeks after severe COVID-19.

COVID 19 is associated with a hypercoagulable state and frequent thromboembolic complications. For how long this acquired abnormality lasts potentially requiring preventive measures, such as anticoagulation remains to be delineated. We used viscoelastic rotational thrombelastometry (ROTEM) in a single center cohort of 13 critical ill patients and performed follow up examinations three months after discharge from ICU. We found clear signs of a hypercoagulable state due to severe hypofibrinolysis and a high rate of thromboembolic complications during the phase of acute illness. Three month follow up revealed normalization of the initial coagulation abnormality and no evidence of venous thrombosis in all thirteen patients. In our cohort the coagulation profile was completely normalized three months after COVID-19. Based on these findings, discontinuation of anticoagulation can be discussed in patients with complete venous reperfusion.

COVID-19-related coagulopathy: A review of pathophysiology and pharmaceutical management.

December 2019 will never be forgotten in the history of medicine when an outbreak of pneumonia of unknown etiology in Wuhan, China sooner or later prompted the World Health Organization to issue a public health warning emergency. This is not the first nor will it be the last time that a member of ß-coronaviruses (CoVs) is waging a full-scale war against human health. Notwithstanding the fact that pneumonia is the primary symptom of the novel coronavirus (2019nCoV; designated as SARS-CoV-2), the emergence of severe disease mainly due to the injury of nonpulmonary organs at the shadow of coagulopathy leaves no choice, in some cases, rather than a dreadful death. Multiple casual factors such as inflammation, endothelial dysfunction, platelet and complement activation, renin-angiotensin-aldosterone system derangement, and hypoxemia play a major role in the pathogenesis of coagulopathy in coronavirus disease 2019 (COVID-19) patients. Due to the undeniable role of coagulation dysfunction in the initiation of several complications, assessment of coagulation parameters and the platelet count would be beneficial in early diagnosis and also timely prediction of disease severity. Although low-molecular-weight heparin is considered as the first-line of treatment in COVID-19-associated coagulopathy, several possible therapeutic options have also been proposed for better management of the disease. In conclusion, this review would help us to gain insight into the pathogenesis, clinical manifestation, and laboratory findings associated with COVID-19 coagulopathy and would summarize management strategies to alleviate coagulopathy-related complications.

Rationales and uncertainties for aspirin use in COVID-19: a narrative review.

OBJECTIVES: To review the pathophysiology of COVID-19 disease, potential aspirin targets on this pathogenesis and the potential role of aspirin in patients with COVID-19. DESIGN: Narrative review. SETTING: The online databases PubMed, OVID Medline and Cochrane Library were searched using relevant headlines from 1 January 2016 to 1 January 2021. International guidelines from relevant societies, journals and forums were also assessed for relevance. PARTICIPANTS: Not applicable. RESULTS: A review of the selected literature revealed that clinical deterioration in COVID-19 is attributed to the interplay between endothelial dysfunction, coagulopathy and dysregulated inflammation. Aspirin has anti-inflammatory effects, antiplatelet aggregation, anticoagulant properties as well as pleiotropic effects on endothelial function. During the COVID-19 pandemic, low-dose aspirin is used effectively in secondary prevention of atherosclerotic cardiovascular disease, prevention of venous thromboembolism after total hip or knee replacement, prevention of pre-eclampsia and postdischarge treatment for multisystem inflammatory syndrome in children. Prehospital low-dose aspirin therapy may reduce the risk of intensive care unit admission and mechanical ventilation in hospitalised patients with COVID-19, whereas aspirin association with mortality is still debatable. CONCLUSION: The authors recommend a low-dose aspirin regimen for primary prevention of arterial thromboembolism in patients aged 40-70 years who are at high atherosclerotic cardiovascular disease risk, or an intermediate risk with a risk-enhancer and have a low risk of bleeding. Aspirin's protective roles in COVID-19 associated with acute lung injury, vascular thrombosis without previous cardiovascular disease and mortality need further randomised controlled trials to establish causal conclusions.

Anticoagulation in COVID-19: current concepts and controversies.

Rising incidence of thromboembolism secondary to COVID-19 has become a global concern, with several surveys reporting increased mortality rates. Thrombogenic potential of the SARS-CoV-2 virus has been hypothesised to originate from its ability to produce an exaggerated inflammatory response leading to endothelial dysfunction. Anticoagulants have remained the primary modality of treatment of thromboembolism for decades. However, there is no universal consensus regarding the timing, dosage and duration of anticoagulation in COVID-19 as well as need for postdischarge prophylaxis. This article seeks to review the present guidelines and recommendations as well as the ongoing trials on use of anticoagulants in COVID-19, identify discrepancies between all these, and provide a comprehensive strategy regarding usage of these drugs in the current pandemic.

Treatment-Dose LMWH versus Prophylactic/Intermediate Dose Heparins in High-Risk COVID-19 Inpatients: Rationale and Design of the HEP-COVID Trial.

Coronavirus disease-2019 (COVID-19) has been associated with significant risk of venous thromboembolism (VTE), arterial thromboembolism (ATE), and mortality particularly among hospitalized patients with critical illness and elevated D-dimer (Dd) levels. Conflicting data have yet to elucidate optimal thromboprophylaxis dosing. HEP-COVID (NCT04401293) is a phase 3, multicenter, pragmatic, prospective, randomized, pseudo-blinded, active control trial to evaluate efficacy and safety of therapeutic-dose low-molecular-weight heparin (LMWH) versus prophylactic-/intermediate-dose LMWH or unfractionated heparin (UFH) for prevention of a primary efficacy composite outcome of VTE, ATE, and all-cause mortality 30 ± 2 days post-enrollment. Eligible patients have COVID-19 diagnosis by nasal swab or serologic testing, requirement for supplemental oxygen per investigator judgment, and Dd >4 × upper limit of normal (ULN) or sepsis-induced coagulopathy score ≥4. Subjects are randomized to enoxaparin 1 mg/kg subcutaneous (SQ)/two times a day (BID) (creatinine clearance [CrCl] ≥ 30 mL/min) or 0.5 mg/kg (CrCl 15-30 mL/min) versus local institutional prophylactic regimens including (1) UFH up to 22,500 IU (international unit) daily (divided BID or three times a day), (2) enoxaparin 30 and 40 mg SQ QD (once daily) or BID, or (3) dalteparin 2,500 IU or 5,000 IU QD. The principal safety outcome is major bleeding. Events are adjudicated locally. Based on expected 40% relative risk reduction with treatment-dose compared with prophylactic-dose prophylaxis, 308 subjects will be enrolled (assuming 20% drop-out) to achieve 80% power. Distinguishing design features include an enriched population for the composite endpoint anchored on Dd >4 × ULN, stratification by intensive care unit (ICU) versus non-ICU, and the ability to capture asymptomatic proximal deep venous thrombosis via screening ultrasonography prior to discharge.