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 0·3­0·7 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 0·59­1·22], 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 1·61­8·27], 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.

Rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve

BACKGROUND The effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain. METHODS In this randomized trial, we compared rivaroxaban (20 mg once daily) with dose adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months. RESULTS A total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], −1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups. CONCLUSIONS In patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months.

Outcomes in anticoagulated patients with atrial fibrillation and with mitral or aortic valve disease

OBJECTIVE: To assess stroke/systemic embolism, major bleeding and other outcomes, and treatment effect of apixaban versus warfarin, in patients with atrial fibrillation (AF) and different types of valvular heart disease (VHD), using data from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial. METHODS: There were 14 793 patients with known VHD status, categorised as having moderate or severe mitral regurgitation (MR) (n=3382), aortic regurgitation (AR) (n=842) or aortic stenosis (AS) (n=324); patients with moderate or severe mitral stenosis were excluded from the trial. Baseline characteristics, efficacy and safety outcomes were compared between each type and no significant VHD. Treatment effect was assessed using an adjusted model. Results Patients with MR or AR had similar rates of stroke/systemic embolism and bleeding compared with patients without MR or AR, respectively. Patients with AS had significantly higher event rates (presented as rate per 100 patient-years of follow-up) of stroke/ systemic embolism (3.47 vs 1.36; adjusted HR (adjHR) 2.21, 95% CI 1.35 to 3.63), death (8.30 vs 3.53; adjHR 1.92, 95% CI 1.41 to 2.61), major bleeding (5.31 vs 2.53; adjHR 1.80, 95% CI 1.19 to 2.75) and intracranial bleeding (1.29 vs 0.51; adjHR 2.54, 95% CI 1.08 to 5.96) than patients without AS. The superiority of apixaban over warfarin on stroke/systemic embolism was similar in patients with versus without MR (HR 0.69, 95% CI 0.46 to 1.04 vs HR 0.79, 95% CI 0.63 to 1.00; interaction P value 0.52), with versus without AR (HR 0.57, 95% CI 0.27 to 1.20 vs HR 0.78, 95% CI 0.63 to 0.96; interaction P value 0.52), and with versus without AS (HR 0.44, 95% CI 0.17 to 1.13 vs HR 0.79, 95% CI 0.64 to 0.97; interaction P value 0.19). For each of the primary and secondary efficacy and safety outcomes, there was no evidence of a different effect of apixaban over warfarin in patients with any VHD subcategory. CONCLUSIONS: In anticoagulated patients with AF, AS is associated with a higher risk of stroke/systemic embolism, bleeding and death. The efficacy and safety benefits of apixaban compared with warfarin were consistent, regardless of presence of MR, AR or AS.

Antithrombotic therapy use and clinical outcomes following thrombo-embolic events in patients with atrial fibrillation: insights from ARISTOTLE

METHOD AND RESULTS:Thrombo-embolic events were defined as stroke (ischaemic or unknown cause) or systemic embolism (SE). Clinical outcomes were estimated using the Kaplan­Meier method. All-cause mortality and International Society on Thrombosis and Haemostasis (ISTH) major bleeding after events were analysed using a Cox proportional hazards model with time-dependent covariates. Of 18 201 patients in ARISTOTLE, 365 experienced a thrombo-embolic event [337 strokes (ischaemic or unknown cause), 28 SE]; 46 (12.6%) of which were fatal. In the 30 days before and after a thrombo-embolic event, 11% and 37% of patients, respectively, were not taking an oral anticoagulant. During follow-up (median 1.8 years), 22 patients (7.1%/year) had a recurrent stroke, 97 (30.1%/year) died, and 10 (6.7%/year) had major bleeding. Compared with patients without a thrombo-embolic event, the short- and long-term adjusted hazards of death in patients with a thrombo-embolic event were high [30 days: HR 3.5, 95% CI 2.5­4.8; both P< 0.001]. The adjusted hazards of major bleeding were also high short-term (HR 10.37, 95% CI 3.87­27.78; P< 0.001) but not long-term (HR 1.7, 95% CI: 0.77­3.88; P= 0.18). CONCLUSIONS: Thrombo-embolic events were rare but associated with high short- and long-term morbidity and mortality. Substantial numbers of patients are not receiving oral anticoagulant therapy before and, despite this risk, after a first thrombo-embolic event.

Clopidogrel use after myocardial revascularization: prevalence, predictors, and one-year survival rate

Abstract Introduction: Antiplatelet therapy after coronary artery bypass graft (CABG) has been used. Little is known about the predictors and efficacy of clopidogrel in this scenario. Objective: Identify predictors of clopidogrel following CABG. Methods: We evaluated 5404 patients who underwent CABG between 2000 and 2009 at Duke University Medical Center. We excluded patients undergoing concomitant valve surgery, those who had postoperative bleeding or death before discharge. Postoperative clopidogrel was left to the discretion of the attending physician. Adjusted risk for 1-year mortality was compared between patients receiving and not receiving clopidogrel during hospitalization after undergoing CABG. Results: At hospital discharge, 931 (17.2%) patients were receiving clopidogrel. Comparing patients not receiving clopidogrel at discharge, users had more comorbidities, including hyperlipidemia, hypertension, heart failure, peripheral arterial disease and cerebrovascular disease. Patients who received aspirin during hospitalization were less likely to receive clopidogrel at discharge (P≤0.0001). Clopidogrel was associated with similar 1-year mortality compared with those who did not use clopidogrel (4.4% vs. 4.5%, P=0.72). There was, however, an interaction between the use of cardiopulmonary bypass and clopidogrel, with lower 1-year mortality in patients undergoing off-pump CABG who received clopidogrel, but not those undergoing conventional CABG (2.6% vs 5.6%, P Interaction = 0.032). Conclusion: Clopidogrel was used in nearly one-fifth of patients after CABG. Its use was not associated with lower mortality after 1 year in general, but lower mortality rate in those undergoing off-pump CABG. Randomized clinical trials are needed to determine the benefit of routine use of clopidogrel in CABG.

Apixaban in Comparison With Warfarin in PatientsWith Atrial Fibrillation and Valvular Heart DiseaseFindings From the Apixaban for Reduction in Stroke and OtherThromboembolic Events in Atrial Fibrillation (ARISTOTLE) Trial

Apixaban is approved for the prevention of stroke and systemic embolism in patients with nonvalvular atrialfibrillation. However, the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation(ARISTOTLE) trial included a substantial number of patients with valvular heart disease and only excluded patients withclinically significant mitral stenosis or mechanical prosthetic heart valves.Methods and Results—We compared the effect of apixaban and warfarin on rates of stroke or systemic embolism, majorbleeding, and death in patients with and without moderate or severe valvular heart disease using Cox proportional hazardsmodeling. Of the 18 201 patients enrolled in ARISTOTLE, 4808 (26.4%) had a history of moderate or severe valvular heartdisease or previous valve surgery. Patients with valvular heart disease had higher rates of stroke or systemic embolismand bleeding than patients without valvular heart disease. There was no evidence of a differential effect of apixaban overwarfarin in patients with and without valvular heart disease in reducing stroke and systemic embolism (hazard ratio [HR],0.70; 95% confidence interval [CI], 0.51–0.97 and HR, 0.84; 95%, CI 0.67–1.04; interaction P=0.38), causing less majorbleeding (HR, 0.79; 95% CI, 0.61–1.04 and HR, 0.65; 95% CI, 0.55–0.77; interaction P=0.23), and reducing mortality(HR, 1.01; 95% CI, 0.84–1.22 and HR, 0.84; 95% CI, 0.73–0.96; interaction P=0.10).Conclusions—More than a quarter of the patients in ARISTOTLE with nonvalvular atrial fibrillation had moderate or severevalvular heart disease. There was no evidence of a differential effect of apixaban over warfarin in reducing stroke orsystemic embolism, causing less bleeding, and reducing death in patients with and without valvular heart disease.