Predictors of bleeding and thrombotic events among patients admitted to the hospital with COVID-19 and elevated D-dimer: insights from the ACTION randomized clinical trial.

Therapeutic anticoagulation showed inconsistent results in hospitalized patients with COVID-19 and selection of the best patients to use this strategy still a challenge balancing the risk of thrombotic and hemorrhagic outcomes. The present post-hoc analysis of the ACTION trial evaluated the variables independently associated with both bleeding events (major bleeding or clinically relevant non-major bleeding) and the composite outcomes thrombotic events (venous thromboembolism, myocardial infarction, stroke, systemic embolism, or major adverse limb events). Variables were assessed one by one with independent logistic regressions and final models were chosen based on Akaike information criteria. The model for bleeding events showed an area under the curve of 0.63 (95% confidence interval [CI] 0.53 to 0.73), while the model for thrombotic events had an area under the curve of 0.72 (95% CI 0.65 to 0.79). Non-invasive respiratory support was associated with thrombotic but not bleeding events, while invasive ventilation was associated with both outcomes (Odds Ratio of 7.03 [95 CI% 1.95 to 25.18] for thrombotic and 3.14 [95% CI 1.11 to 8.84] for bleeding events). Beyond respiratory support, creatinine level (Odds Ratio [OR] 1.01 95% CI 1.00 to 1.02 for every 1.0 mg/dL) and history of coronary disease (OR 3.67; 95% CI 1.32 to 10.29) were also independently associated to the risk of thrombotic events. Non-invasive respiratory support, history of coronary disease, and creatinine level may help to identify hospitalized COVID-19 patients at higher risk of thrombotic complications.ClinicalTrials.gov: NCT04394377.

Rivaroxaban versus no anticoagulation for post-discharge thromboprophylaxis after hospitalisation for COVID-19 (MICHELLE): an open-label, multicentre, randomised, controlled trial.

BACKGROUND: Patients hospitalised with COVID-19 are at risk for thrombotic events after discharge; the role of extended thromboprophylaxis in this population is unknown. METHODS: In this open-label, multicentre, randomised trial conducted at 14 centres in Brazil, patients hospitalised with COVID-19 at increased risk for venous thromboembolism (International Medical Prevention Registry on Venous Thromboembolism [IMPROVE] venous thromboembolism [VTE] score of ≥4 or 2-3 with a D-dimer >500 ng/mL) were randomly assigned (1:1) to receive, at hospital discharge, rivaroxaban 10 mg/day or no anticoagulation for 35 days. The primary efficacy outcome in an intention-to-treat analysis was a composite of symptomatic or fatal venous thromboembolism, asymptomatic venous thromboembolism on bilateral lower-limb venous ultrasound and CT pulmonary angiogram, symptomatic arterial thromboembolism, and cardiovascular death at day 35. Adjudication was blinded. The primary safety outcome was major bleeding. The primary and safety analyses were carried out in the intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT04662684. FINDINGS: From Oct 8, 2020, to June 29, 2021, 997 patients were screened. Of these patients, 677 did not meet eligibility criteria; the remaining 320 patients were enrolled and randomly assigned to receive rivaroxaban (n=160 [50%]) or no anticoagulation (n=160 [50%]). All patients received thromboprophylaxis with standard doses of heparin during hospitalisation. 165 (52%) patients were in the intensive care unit while hospitalised. 197 (62%) patients had an IMPROVE score of 2-3 and elevated D-dimer levels and 121 (38%) had a score of 4 or more. Two patients (one in each group) were lost to follow-up due to withdrawal of consent and not included in the intention-to-treat primary analysis. The primary efficacy outcome occurred in five (3%) of 159 patients assigned to rivaroxaban and 15 (9%) of 159 patients assigned to no anticoagulation (relative risk 0·33, 95% CI 0·12-0·90; p=0·0293). No major bleeding occurred in either study group. Allergic reactions occurred in two (1%) patients in the rivaroxaban group. INTERPRETATION: In patients at high risk discharged after hospitalisation due to COVID-19, thromboprophylaxis with rivaroxaban 10 mg/day for 35 days improved clinical outcomes compared with no extended thromboprophylaxis. FUNDING: Bayer.

Therapeutic versus prophylactic anticoagulation for patients admitted to hospital with COVID-19 and elevated D-dimer concentration (ACTION): an open-label, multicentre, randomised, controlled trial.

BACKGROUND: COVID-19 is associated with a prothrombotic state leading to adverse clinical outcomes. Whether therapeutic anticoagulation improves outcomes in patients hospitalised with COVID-19 is unknown. We aimed to compare the efficacy and safety of therapeutic versus prophylactic anticoagulation in this population. METHODS: We did a pragmatic, open-label (with blinded adjudication), multicentre, randomised, controlled trial, at 31 sites in Brazil. Patients (aged ≥18 years) hospitalised with COVID-19 and elevated D-dimer concentration, and who had COVID-19 symptoms for up to 14 days before randomisation, were randomly assigned (1:1) to receive either therapeutic or prophylactic anticoagulation. Therapeutic anticoagulation was in-hospital oral rivaroxaban (20 mg or 15 mg daily) for stable patients, or initial subcutaneous enoxaparin (1 mg/kg twice per day) or intravenous unfractionated heparin (to achieve a 0·3-0·7 IU/mL anti-Xa concentration) for clinically unstable patients, followed by rivaroxaban to day 30. Prophylactic anticoagulation was standard in-hospital enoxaparin or unfractionated heparin. The primary efficacy outcome was a hierarchical analysis of time to death, duration of hospitalisation, or duration of supplemental oxygen to day 30, analysed with the win ratio method (a ratio >1 reflects a better outcome in the therapeutic anticoagulation group) in the intention-to-treat population. The primary safety outcome was major or clinically relevant non-major bleeding through 30 days. This study is registered with ClinicalTrials.gov (NCT04394377) and is completed. FINDINGS: From June 24, 2020, to Feb 26, 2021, 3331 patients were screened and 615 were randomly allocated (311 [50%] to the therapeutic anticoagulation group and 304 [50%] to the prophylactic anticoagulation group). 576 (94%) were clinically stable and 39 (6%) clinically unstable. One patient, in the therapeutic group, was lost to follow-up because of withdrawal of consent and was not included in the primary analysis. The primary efficacy outcome was not different between patients assigned therapeutic or prophylactic anticoagulation, with 28 899 (34·8%) wins in the therapeutic group and 34 288 (41·3%) in the prophylactic group (win ratio 0·86 [95% CI 0·59-1·22], p=0·40). Consistent results were seen in clinically stable and clinically unstable patients. The primary safety outcome of major or clinically relevant non-major bleeding occurred in 26 (8%) patients assigned therapeutic anticoagulation and seven (2%) assigned prophylactic anticoagulation (relative risk 3·64 [95% CI 1·61-8·27], p=0·0010). Allergic reaction to the study medication occurred in two (1%) patients in the therapeutic anticoagulation group and three (1%) in the prophylactic anticoagulation group. INTERPRETATION: In patients hospitalised with COVID-19 and elevated D-dimer concentration, in-hospital therapeutic anticoagulation with rivaroxaban or enoxaparin followed by rivaroxaban to day 30 did not improve clinical outcomes and increased bleeding compared with prophylactic anticoagulation. Therefore, use of therapeutic-dose rivaroxaban, and other direct oral anticoagulants, should be avoided in these patients in the absence of an evidence-based indication for oral anticoagulation. FUNDING: Coalition COVID-19 Brazil, Bayer SA.

Randomized clinical trial to evaluate a routine full anticoagulation Strategy in Patients with Coronavirus Infection (SARS-CoV2) admitted to hospital: Rationale and design of the ACTION (AntiCoagulaTlon cOroNavirus)-Coalition IV trial.

BACKGROUND: Observational studies have suggested a higher risk of thrombotic events in patients with coronavirus disease 2019 (COVID-19). Moreover, elevated D-dimer levels have been identified as an important prognostic marker in COVID-19 directly associated with disease severity and progression. Prophylactic anticoagulation for hospitalized COVID-19 patients might not be enough to prevent thrombotic events; therefore, therapeutic anticoagulation regimens deserve clinical investigation. DESIGN: ACTION is an academic-led, pragmatic, multicenter, open-label, randomized, phase IV clinical trial that aims to enroll around 600 patients at 40 sites participating in the Coalition COVID-19 Brazil initiative. Eligible patients with a confirmed diagnosis of COVID-19 with symptoms up to 14 days and elevated D-dimer levels will be randomized to a strategy of full-dose anticoagulation for 30 days with rivaroxaban 20 mg once daily (or full-dose heparin if oral administration is not feasible) vs standard of care with any approved venous thromboembolism prophylaxis regimen during hospitalization. A confirmation of COVID-19 was mandatory for study entry, based on specific tests used in clinical practice (RT-PCR, antigen test, IgM test) collected before randomization, regardless of in the outpatient setting or not. Randomization will be stratified by clinical stability at presentation. The primary outcome is a hierarchical analysis of mortality, length of hospital stay, or duration of oxygen therapy at the end of 30 days. Secondary outcomes include the World Health Organization's 8-point ordinal scale at 30 days and the following efficacy outcomes: incidence of venous thromboembolism , acute myocardial infarction, stroke, systemic embolism, major adverse limb events, duration of oxygen therapy, disease progression, and biomarkers. The primary safety outcomes are major or clinically relevant non-major bleeding according to the International Society on Thrombosis and Haemostasis criteria. SUMMARY: The ACTION trial will evaluate whether in-hospital therapeutic anticoagulation with rivaroxaban for stable patients, or enoxaparin for unstable patients, followed by rivaroxaban through 30 days compared with standard prophylactic anticoagulation improves clinical outcomes in hospitalized patients with COVID-19 and elevated D-dimer levels.

Medically Ill hospitalized Patients for COVID-19 THrombosis Extended ProphyLaxis with rivaroxaban ThErapy: Rationale and Design of the MICHELLE Trial.

BACKGROUND: The devastating Coronavirus disease (COVID-19) pandemic is associated with a high prothrombotic state. It is unclear if the coagulation abnormalities occur because of the direct effect of SARS-CoV-2 or indirectly by the cytokine storm and endothelial damage or by a combination of mechanisms. There is a clear indication of in-hospital pharmacological thromboprophylaxis for every patient with COVID-19 after bleed risk assessment. However, there is much debate regarding the best dosage regimen, and there is no consensus on the role of extended thromboprophylaxis. DESIGN: This study aims to evaluate the safety and efficacy of rivaroxaban 10 mg once daily for 35 ± 4 days versus no intervention after hospital discharge in COVID-19 patients who were at increased risk for VTE and have received standard parenteral VTE prophylaxis during hospitalization. The composite efficacy endpoint is a combination of symptomatic VTE, VTE-related death, VTE detected by bilateral lower limbs venous duplex scan and computed tomography pulmonary angiogram on day 35 ± 4 posthospital discharge and symptomatic arterial thromboembolism (myocardial infarction, nonhemorrhagic stroke, major adverse limb events, and cardiovascular death) up to day 35 ± 4 posthospital discharge. The key safety outcome is the incidence of major bleeding according to ISTH criteria. SUMMARY: The MICHELLE trial is expected to provide high-quality evidence around the role of extended thromboprophylaxis in COVID-19 and will help guide medical decisions in clinical practice.1.

Rationale and design for the study Apixaban versus ClopidoGRel on a background of aspirin in patient undergoing InfraPoPliteal angioplasty for critical limb ischemia: AGRIPPA trial.

BACKGROUND: New antithrombotic strategies that reduce primary thrombosis and restenosis might improve vascular outcomes in patients with peripheral artery disease (PAD) undergoing arterial angioplasty. The study objective is to evaluate the potential benefit of apixaban plus aspirin compared with standard of care dual antiplatelet therapy (DAPT) in reducing thrombotic restenosis and artery re-occlusion in patients undergoing endovascular infrapopliteal revascularization. STUDY DESIGN: This multicenter, parallel-group, prospective, randomized, open-label, blinded-endpoint adjudication, proof-of-concept, exploratory trial aims to randomize 200 patients 72 hours after successful infrapopliteal angioplasty for critical limb ischemia (CLI). Patients will be randomly assigned in a 1:1 ratio to receive oral apixaban (2.5 mg twice daily) plus aspirin (100 mg once daily) for 12 months or clopidogrel (75 mg daily) for at least 3 months on a background of aspirin (100 mg once daily) for 12 months. The primary endpoint is the composite of target lesion revascularization (TLR), major amputation, or restenosis/occlusion (RAS) in addition to major adverse cardiovascular events - MACE (myocardial infarction, stroke or cardiovascular death) at 12 months. The primary safety endpoint is the composite of major bleeding or clinically relevant non-major bleeding at 12 months. SUMMARY: This study will evaluate the efficacy and safety of apixaban 2.5 mg twice daily plus aspirin compared with DAPT (clopidogrel plus aspirin) in patients with CLI undergoing endovascular infrapopliteal revascularization and might prove the concept of an alternative antithrombotic regimen for these patients to be tested in a future large randomized clinical trial.

Apixaban Versus Warfarin for Mechanical Heart Valve Thromboprophylaxis in a Swine Aortic Heterotopic Valve Model.

OBJECTIVE: Warfarin is the current standard for oral anticoagulation therapy in patients with mechanical heart valves, yet optimal therapy to maximize anticoagulation and minimize bleeding complications requires routine coagulation monitoring, possible dietary restrictions, and drug interaction monitoring. As alternatives to warfarin, oral direct acting factor Xa inhibitors are currently approved for the prophylaxis and treatment of venous thromboembolism and reduction of stroke and systemic embolization. However, no in vivo preclinical or clinical studies have been performed directly comparing oral factor Xa inhibitors such as apixaban to warfarin, the current standard of therapy. APPROACH AND RESULTS: A well-documented heterotopic aortic valve porcine model was used to test the hypothesis that apixaban has comparable efficacy to warfarin for thromboprophylaxis of mechanical heart valves. Sixteen swine were implanted with a bileaflet mechanical aortic valve that bypassed the ligated descending thoracic aorta. Animals were randomized to 4 groups: control (no anticoagulation; n=4), apixaban oral 1 mg/kg twice a day (n=5), warfarin oral 0.04 to 0.08 mg/kg daily (international normalized ratio 2-3; n=3), and apixaban infusion (n=4). Postmortem valve thrombus was measured 30 days post-surgery for control-oral groups and 14 days post-surgery for the apixaban infusion group. Control thrombus weight (mean) was significantly different (1422.9 mg) compared with apixaban oral (357.5 mg), warfarin (247.1 mg), and apixiban 14-day infusion (61.1 mg; P<0.05). CONCLUSIONS: Apixaban is a promising candidate and may be a useful alternative to warfarin for thromboprophylaxis of mechanical heart valves. Unlike warfarin, no adverse bleeding events were observed in any apixaban groups.

Warfarin Discontinuation in Patients With Unprovoked Venous Thromboembolism: A Large US Insurance Database Analysis.

This study examined warfarin therapy discontinuation and its risk factors among patients with unprovoked venous thromboembolism (VTE) in the US clinical practice setting. Adult patients with unprovoked VTE were identified from the MarketScan claims database from January 1, 2006 to December 31, 2012. The index date was defined as the date of first VTE diagnosis. Patients were required to have no VTE diagnosis in the 6 months before index date and continuous health plan enrollment for 6 months before and 12 months after the index date. Warfarin discontinuation rates and adjusted hazard ratios (HRs) were reported. Of 21,163 eligible patients, 15,463 were diagnosed with deep vein thrombosis (DVT) only (73.1%), 5027 with pulmonary embolism (PE) only (23.7%), and 673 with DVT and PE (3.2%). The average duration of warfarin therapy was 5.2 months (SD = 3.0). During 1-year follow-up, 21.4% patients discontinued therapy within 3 months, 42.8% within 6 months, and 70.1% within 12 months. PE versus DVT [HR = 0.77, 95% confidence interval (CI) = 0.74-0.80], comorbid atrial fibrillation (HR = 0.73, 95% CI = 0.66-0.81), thrombophilia (HR = 0.62, 95% CI = 0.54-0.71), and age >40 years (41-65 years: HR = 0.86, 95% CI = 0.81-0.91; >65 years: HR = 0.82, 95% CI = 0.77-0.87) were significantly associated with reduced risk of warfarin discontinuation. Alcohol abuse/dependence (HR = 1.36, 95% CI = 1.20-1.55), cancer history (HR = 1.13, 95% CI = 1.07-1.19), bleeding (HR = 1.07, 95% CI = 1.01-1.15), and catheter ablation (HR = 1.10, 95% CI = 1.00-1.20) in the 6 months before index date were significantly associated with increased risk for warfarin discontinuation. In conclusion, nearly 1 of 4 patients with unprovoked VTE discontinued warfarin within 3 months. Three of 4 patients discontinued therapy within 1 year. Younger age and multiple clinical factors are associated with warfarin therapy discontinuation.

Pharmacological Prophylaxis for Venous Thromboembolism Among Hospitalized Patients With Acute Medical Illness: An Electronic Medical Records Study.

Patients hospitalized with acute medical illness have an elevated risk of venous thromboembolism (VTE). American College of Chest Physicians guidelines list various chronic illnesses, sepsis, advanced age, history of VTE, and immobility as risk factors and recommend prophylactic anticoagulation using fondaparinux, low-molecular weight heparin, or low-dose unfractionated heparin. The objectives of this study were to examine pharmacological prophylaxis against VTE among hospitalized medically ill patients and to assess demographic and clinical correlates related to VTE prophylaxis. A retrospective (1999-2010) electronic medical records study included patients aged 40 years and older hospitalized for at least 3 days, with significant medical illness or with a VTE hospitalization 30-365 days before admission. Each patient's first qualifying hospitalization was analyzed. Exclusions were if VTE treatment was started within 1 day of admission, or if warfarin (and not heparin or enoxaparin) was used. Prophylaxis was defined if the first inpatient dose of subcutaneous heparin or enoxaparin was at prophylaxis levels (lower than treatment levels). Multivariable logistic regression was used to examine factors associated with VTE prophylaxis. Among 12,980 patients, 22.1% received prophylaxis (11.8% with enoxaparin, 10.3% with heparin). VTE prophylaxis was positively associated with year of hospitalization, subcutaneous heparin in the month before admission, aspirin, self-pay status, age, and sepsis. VTE prophylaxis was negatively associated with smoking, alcohol, warfarin in the past 30 days, and primary diagnoses of stroke, infectious disease, or inflammatory bowel disease. Pharmacological VTE prophylaxis has increased significantly over the past 12 years but is still largely underused in patients hospitalized with acute medical illness. Multiple demographic, behavioral, and clinical factors are associated with inpatient VTE prophylaxis.