Therapeutic Anticoagulation with Heparin in Critically Ill Patients with Covid-19.

BACKGROUND: Thrombosis and inflammation may contribute to morbidity and mortality among patients with coronavirus disease 2019 (Covid-19). We hypothesized that therapeutic-dose anticoagulation would improve outcomes in critically ill patients with Covid-19. METHODS: In an open-label, adaptive, multiplatform, randomized clinical trial, critically ill patients with severe Covid-19 were randomly assigned to a pragmatically defined regimen of either therapeutic-dose anticoagulation with heparin or pharmacologic thromboprophylaxis in accordance with local usual care. The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death (assigned a value of -1) and the number of days free of cardiovascular or respiratory organ support up to day 21 among patients who survived to hospital discharge. RESULTS: The trial was stopped when the prespecified criterion for futility was met for therapeutic-dose anticoagulation. Data on the primary outcome were available for 1098 patients (534 assigned to therapeutic-dose anticoagulation and 564 assigned to usual-care thromboprophylaxis). The median value for organ support-free days was 1 (interquartile range, -1 to 16) among the patients assigned to therapeutic-dose anticoagulation and was 4 (interquartile range, -1 to 16) among the patients assigned to usual-care thromboprophylaxis (adjusted proportional odds ratio, 0.83; 95% credible interval, 0.67 to 1.03; posterior probability of futility [defined as an odds ratio <1.2], 99.9%). The percentage of patients who survived to hospital discharge was similar in the two groups (62.7% and 64.5%, respectively; adjusted odds ratio, 0.84; 95% credible interval, 0.64 to 1.11). Major bleeding occurred in 3.8% of the patients assigned to therapeutic-dose anticoagulation and in 2.3% of those assigned to usual-care pharmacologic thromboprophylaxis. CONCLUSIONS: In critically ill patients with Covid-19, an initial strategy of therapeutic-dose anticoagulation with heparin did not result in a greater probability of survival to hospital discharge or a greater number of days free of cardiovascular or respiratory organ support than did usual-care pharmacologic thromboprophylaxis. (REMAP-CAP, ACTIV-4a, and ATTACC ClinicalTrials.gov numbers, NCT02735707, NCT04505774, NCT04359277, and NCT04372589.).

Therapeutic Anticoagulation with Heparin in Noncritically Ill Patients with Covid-19.

BACKGROUND: Thrombosis and inflammation may contribute to the risk of death and complications among patients with coronavirus disease 2019 (Covid-19). We hypothesized that therapeutic-dose anticoagulation may improve outcomes in noncritically ill patients who are hospitalized with Covid-19. METHODS: In this open-label, adaptive, multiplatform, controlled trial, we randomly assigned patients who were hospitalized with Covid-19 and who were not critically ill (which was defined as an absence of critical care-level organ support at enrollment) to receive pragmatically defined regimens of either therapeutic-dose anticoagulation with heparin or usual-care pharmacologic thromboprophylaxis. The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death (assigned a value of -1) and the number of days free of cardiovascular or respiratory organ support up to day 21 among patients who survived to hospital discharge. This outcome was evaluated with the use of a Bayesian statistical model for all patients and according to the baseline d-dimer level. RESULTS: The trial was stopped when prespecified criteria for the superiority of therapeutic-dose anticoagulation were met. Among 2219 patients in the final analysis, the probability that therapeutic-dose anticoagulation increased organ support-free days as compared with usual-care thromboprophylaxis was 98.6% (adjusted odds ratio, 1.27; 95% credible interval, 1.03 to 1.58). The adjusted absolute between-group difference in survival until hospital discharge without organ support favoring therapeutic-dose anticoagulation was 4.0 percentage points (95% credible interval, 0.5 to 7.2). The final probability of the superiority of therapeutic-dose anticoagulation over usual-care thromboprophylaxis was 97.3% in the high d-dimer cohort, 92.9% in the low d-dimer cohort, and 97.3% in the unknown d-dimer cohort. Major bleeding occurred in 1.9% of the patients receiving therapeutic-dose anticoagulation and in 0.9% of those receiving thromboprophylaxis. CONCLUSIONS: In noncritically ill patients with Covid-19, an initial strategy of therapeutic-dose anticoagulation with heparin increased the probability of survival to hospital discharge with reduced use of cardiovascular or respiratory organ support as compared with usual-care thromboprophylaxis. (ATTACC, ACTIV-4a, and REMAP-CAP ClinicalTrials.gov numbers, NCT04372589, NCT04505774, NCT04359277, and NCT02735707.).

A comparison of computational algorithms for the Bayesian analysis of clinical trials.

BACKGROUND: Clinical trials are increasingly using Bayesian methods for their design and analysis. Inference in Bayesian trials typically uses simulation-based approaches such as Markov Chain Monte Carlo methods. Markov Chain Monte Carlo has high computational cost and can be complex to implement. The Integrated Nested Laplace Approximations algorithm provides approximate Bayesian inference without the need for computationally complex simulations, making it more efficient than Markov Chain Monte Carlo. The practical properties of Integrated Nested Laplace Approximations compared to Markov Chain Monte Carlo have not been considered for clinical trials. Using data from a published clinical trial, we aim to investigate whether Integrated Nested Laplace Approximations is a feasible and accurate alternative to Markov Chain Monte Carlo and provide practical guidance for trialists interested in Bayesian trial design. METHODS: Data from an international Bayesian multi-platform adaptive trial that compared therapeutic-dose anticoagulation with heparin to usual care in non-critically ill patients hospitalized for COVID-19 were used to fit Bayesian hierarchical generalized mixed models. Integrated Nested Laplace Approximations was compared to two Markov Chain Monte Carlo algorithms, implemented in the software JAGS and stan, using packages available in the statistical software R. Seven outcomes were analysed: organ-support free days (an ordinal outcome), five binary outcomes related to survival and length of hospital stay, and a time-to-event outcome. The posterior distributions for the treatment and sex effects and the variances for the hierarchical effects of age, site and time period were obtained. We summarized these posteriors by calculating the mean, standard deviations and the 95% equitailed credible intervals and presenting the results graphically. The computation time for each algorithm was recorded. RESULTS: The average overlap of the 95% credible interval for the treatment and sex effects estimated using Integrated Nested Laplace Approximations was 96% and 97.6% compared with stan, respectively. The graphical posterior densities for these effects overlapped for all three algorithms. The posterior mean for the variance of the hierarchical effects of age, site and time estimated using Integrated Nested Laplace Approximations are within the 95% credible interval estimated using Markov Chain Monte Carlo but the average overlap of the credible interval is lower, 77%, 85.6% and 91.3%, respectively, for Integrated Nested Laplace Approximations compared to stan. Integrated Nested Laplace Approximations and stan were easily implemented in clear, well-established packages in R, while JAGS required the direct specification of the model. Integrated Nested Laplace Approximations was between 85 and 269 times faster than stan and 26 and 1852 times faster than JAGS. CONCLUSION: Integrated Nested Laplace Approximations could reduce the computational complexity of Bayesian analysis in clinical trials as it is easy to implement in R, substantially faster than Markov Chain Monte Carlo methods implemented in JAGS and stan, and provides near identical approximations to the posterior distributions for the treatment effect. Integrated Nested Laplace Approximations was less accurate when estimating the posterior distribution for the variance of hierarchical effects, particularly for the proportional odds model, and future work should determine if the Integrated Nested Laplace Approximations algorithm can be adjusted to improve this estimation.

Medical Masks Versus N95 Respirators for Preventing COVID-19 Among Health Care Workers : A Randomized Trial.

BACKGROUND: It is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators. OBJECTIVE: To determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care. DESIGN: Multicenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643). SETTING: 29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022. PARTICIPANTS: 1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19. INTERVENTION: Use of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site. MEASUREMENTS: The primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test. RESULTS: In the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group. LIMITATION: Potential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination. CONCLUSION: Among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity. PRIMARY FUNDING SOURCE: Canadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.

Heterogeneous Treatment Effects of Therapeutic-Dose Heparin in Patients Hospitalized for COVID-19.

Importance: Randomized clinical trials (RCTs) of therapeutic-dose heparin in patients hospitalized with COVID-19 produced conflicting results, possibly due to heterogeneity of treatment effect (HTE) across individuals. Better understanding of HTE could facilitate individualized clinical decision-making. Objective: To evaluate HTE of therapeutic-dose heparin for patients hospitalized for COVID-19 and to compare approaches to assessing HTE. Design, Setting, and Participants: Exploratory analysis of a multiplatform adaptive RCT of therapeutic-dose heparin vs usual care pharmacologic thromboprophylaxis in 3320 patients hospitalized for COVID-19 enrolled in North America, South America, Europe, Asia, and Australia between April 2020 and January 2021. Heterogeneity of treatment effect was assessed 3 ways: using (1) conventional subgroup analyses of baseline characteristics, (2) a multivariable outcome prediction model (risk-based approach), and (3) a multivariable causal forest model (effect-based approach). Analyses primarily used bayesian statistics, consistent with the original trial. Exposures: Participants were randomized to therapeutic-dose heparin or usual care pharmacologic thromboprophylaxis. Main Outcomes and Measures: Organ support-free days, assigning a value of -1 to those who died in the hospital and the number of days free of cardiovascular or respiratory organ support up to day 21 for those who survived to hospital discharge; and hospital survival. Results: Baseline demographic characteristics were similar between patients randomized to therapeutic-dose heparin or usual care (median age, 60 years; 38% female; 32% known non-White race; 45% Hispanic). In the overall multiplatform RCT population, therapeutic-dose heparin was not associated with an increase in organ support-free days (median value for the posterior distribution of the OR, 1.05; 95% credible interval, 0.91-1.22). In conventional subgroup analyses, the effect of therapeutic-dose heparin on organ support-free days differed between patients requiring organ support at baseline or not (median OR, 0.85 vs 1.30; posterior probability of difference in OR, 99.8%), between females and males (median OR, 0.87 vs 1.16; posterior probability of difference in OR, 96.4%), and between patients with lower body mass index (BMI <30) vs higher BMI groups (BMI ≥30; posterior probability of difference in ORs >90% for all comparisons). In risk-based analysis, patients at lowest risk of poor outcome had the highest propensity for benefit from heparin (lowest risk decile: posterior probability of OR >1, 92%) while those at highest risk were most likely to be harmed (highest risk decile: posterior probability of OR <1, 87%). In effect-based analysis, a subset of patients identified at high risk of harm (P = .05 for difference in treatment effect) tended to have high BMI and were more likely to require organ support at baseline. Conclusions and Relevance: Among patients hospitalized for COVID-19, the effect of therapeutic-dose heparin was heterogeneous. In all 3 approaches to assessing HTE, heparin was more likely to be beneficial in those who were less severely ill at presentation or had lower BMI and more likely to be harmful in sicker patients and those with higher BMI. The findings illustrate the importance of considering HTE in the design and analysis of RCTs. Trial Registration: ClinicalTrials.gov Identifiers: NCT02735707, NCT04505774, NCT04359277, NCT04372589.

Prognostic Factors Associated With Development of Venous Thromboembolism in Critically Ill Patients-A Systematic Review and Meta-Analysis.

OBJECTIVE: To identify prognostic factors for the development of venous thromboembolism in the ICU. DATA SOURCES: We searched MEDLINE, EMBASE, and Cochrane CENTRAL from inception to March 1, 2021. STUDY SELECTION: We included English-language studies describing prognostic factors associated with the development of venous thromboembolism among critically ill patients. DATA EXTRACTION: Two authors performed data extraction and risk-of-bias assessment. We pooled adjusted odds ratios and adjusted hazard ratios for prognostic factors using random-effects model. We assessed risk of bias using the Quality in Prognosis Studies tool and certainty of evidence using the Grading of Recommendations, Assessment, Development and Evaluations approach. DATA SYNTHESIS: We included 39 observational cohort studies involving 729,477 patients. Patient factors with high or moderate certainty of association with increased odds of venous thromboembolism include older age (adjusted odds ratio, 1.15; 95% CI, 1.02-1.29 per 10 yr), obesity (adjusted odds ratio, 1.25; 95% CI, 1.18-1.32), active malignancy (adjusted odds ratio, 1.70; 95% CI, 1.18-2.44), history of venous thromboembolism (adjusted odds ratio, 4.77; 95% CI, 3.42-6.65), and history of recent surgery (adjusted odds ratio, 1.77; 95% CI, 1.26-2.47). ICU-specific factors with high or moderate certainty of association with increased risk of venous thromboembolism include sepsis (adjusted odds ratio, 1.41; 95% CI, 1.12-1.78), lack of pharmacologic venous thromboembolism prophylaxis (adjusted odds ratio, 1.80; 95% CI, 1.14-2.84), central venous catheter (adjusted odds ratio, 2.93; 95% CI, 1.98-4.34), invasive mechanical ventilation (adjusted odds ratio, 1.74; 95% CI, 1.36-2.24), and use of vasoactive medication (adjusted odds ratio, 1.86; 95% CI, 1.23-2.81). CONCLUSIONS: This meta-analysis provides quantitative summaries of the association between patient-specific and ICU-related prognostic factors and the risk of venous thromboembolism in the ICU. These findings provide the foundation for the development of a venous thromboembolism risk stratification tool for critically ill patients.

Impact of Anticoagulation on Mortality and Resource Utilization Among Critically Ill Patients With Major Bleeding.

OBJECTIVES: Patients with major bleeding are commonly admitted to the ICU. A growing number are on either oral or parenteral anticoagulation, but the impact of anticoagulation on patient outcomes is unknown. We sought to examine this association between anticoagulation therapy and mortality, as well as the independent effects of warfarin compared to direct oral anticoagulants. DESIGN: Analysis of a prospectively collected registry (2011-2017) of consecutive ICU patients admitted with major bleeding (as defined by International Society on Thrombosis and Haemostasis clinical criteria). SETTING: Two hospitals within a single tertiary care level hospital system. PATIENTS: We analyzed 1,598 patients identified with major bleeding, of which 245 (15.3%) had been using anticoagulation at the time of ICU admission. Of patients on anticoagulation, 149 were using warfarin, and 60 were using a direct oral anticoagulant. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome, in-hospital mortality, was analyzed using a multivariable logistic regression model. Patients with anticoagulation-associated major bleeding had higher in-hospital mortality (adjusted odds ratio, 1.49; 95% CI, 1.16-1.92). Among survivors, anticoagulation use was associated with longer median hospital length of stay, and higher mean costs. No differences in hospital mortality were seen between warfarin- and direct oral anticoagulant-associated major bleeding. Patients with warfarin-associated major bleeding had longer median length of stay (11 vs 6 d; p = 0.02), and higher total costs than patients with direct oral anticoagulant-associated major bleeding. CONCLUSIONS: Among ICU patients admitted with major bleeding, pre-admission anticoagulation use was associated with increased hospital mortality, prolonged length of stay, and higher costs among survivors. As compared to direct oral anticoagulants, patients with warfarin-associated major bleeding had increased length of stay and costs. These findings have important implications in the care of ICU patients with major bleeding.

Outcomes of hospitalized hematologic oncology patients receiving rapid response system activation for acute deterioration.

BACKGROUND: Patients with hematologic malignancies who are admitted to hospital are at increased risk of deterioration and death. Rapid response systems (RRSs) respond to hospitalized patients who clinically deteriorate. We sought to describe the characteristics and outcomes of hematologic oncology inpatients requiring rapid response system (RRS) activation, and to determine the prognostic accuracy of the SIRS and qSOFA criteria for in-hospital mortality of hematologic oncology patients with suspected infection. METHODS: We used registry data from two hospitals within The Ottawa Hospital network, between 2012 and 2016. Consecutive hematologic oncology inpatients who experienced activation of the RRS were included in the study. Data was gathered at the time of RRS activation and assessment. The primary outcome was in-hospital mortality. Logistical regression was used to evaluate for predictors of in-hospital mortality. RESULTS: We included 401 patients during the study period. In-hospital mortality for all included patients was 41.9% (168 patients), and 145 patients (45%) were admitted to ICU following RRS activation. Among patients with suspected infection at the time of RRS activation, Systemic Inflammatory Response Syndrome (SIRS) criteria had a sensitivity of 86.9% (95% CI 80.9-91.6) and a specificity of 38.2% (95% CI 31.9-44.8) for predicting in-hospital mortality, while Quick Sequential Organ Failure Assessment (qSOFA) criteria had a sensitivity of 61.9% (95% CI 54.1-69.3) and a specificity of 91.4% (95% CI 87.1-94.7). Factors associated with increased in-hospital mortality included transfer to ICU after RRS activation (adjusted odds ratio [OR] 3.56, 95% CI 2.12-5.97) and a higher number of RRS activations (OR 2.45, 95% CI 1.63-3.69). Factors associated with improved survival included active malignancy treatment at the time of RRS activation (OR 0.54, 95% CI 0.34-0.86) and longer hospital length of stay (OR 0.78, 95% CI 0.70-0.87). CONCLUSIONS: Hematologic oncology inpatients requiring RRS activation have high rates of subsequent ICU admission and mortality. ICU admission and higher number of RRS activations are associated with increased risk of death, while active cancer treatment and longer hospital stay are associated with lower risk of mortality. Clinicians should consider these factors in risk-stratifying these patients during RRS assessment.

Clinical and safety outcomes associated with treatment of acute venous thromboembolism: a systematic review and meta-analysis.

IMPORTANCE: Many anticoagulant strategies are available for the treatment of acute venous thromboembolism, yet little guidance exists regarding which drug is most effective and safe. OBJECTIVE: To summarize and compare the efficacy and safety outcomes associated with 8 anticoagulation options (unfractionated heparin [UFH], low-molecular-weight heparin [LMWH], or fondaparinux in combination with vitamin K antagonists); LMWH with dabigatran or edoxaban; rivaroxaban; apixaban; and LMWH alone) for treatment of venous thromboembolism. DATA SOURCES: A systematic literature search was conducted using MEDLINE, EMBASE, and the evidence-based medicine reviews from inception through February 28, 2014. STUDY SELECTION: Eligible studies were randomized trials reporting rates of recurrent venous thromboembolism and major bleeding in patients with acute venous thromboembolism. Of the 1197 studies identified, 45 trials including 44,989 patients were included in the analyses. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently extracted trial-level data including number of patients, duration of follow-up, and outcomes. The data were pooled using network meta-analysis. MAIN OUTCOMES AND MEASURES: The primary clinical and safety outcomes were recurrent venous thromboembolism and major bleeding, respectively. RESULTS: Compared with the LMWH-vitamin K antagonist combination, a treatment strategy using the UFH-vitamin K antagonist combination was associated with an increased risk of recurrent venous thromboembolism (hazard ratio [HR], 1.42; 95% credible interval [CrI], 1.15-1.79). The proportion of patients experiencing recurrent venous thromboembolism during 3 months of treatment were 1.84% (95% CrI, 1.33%-2.51%) for the UFH-vitamin K antagonist combination and 1.30% (95% CrI, 1.02%-1.62%) for the LMWH-vitamin K antagonist combination. Rivaroxaban (HR, 0.55; 95% CrI, 0.35-0.89) and apixaban (HR, 0.31; 95% CrI, 0.15-0.62) were associated with a lower risk of bleeding than was the LMWH-vitamin K antagonist combination, with a lower proportion of patients experiencing a major bleeding event during 3 months of anticoagulation: 0.49% (95% CrI, 0.29%-0.85%) for rivaroxaban, 0.28% (95% CrI, 0.14%-0.50%) for apixaban, and 0.89% (95% CrI, 0.66%-1.16%) for the LMWH-vitamin K antagonist combination. CONCLUSIONS AND RELEVANCE: Using meta-analytic pooling, there were no statistically significant differences for efficacy and safety associated with most treatment strategies used to treat acute venous thromboembolism compared with the LMWH-vitamin K antagonist combination. However, findings suggest that the UFH-vitamin K antagonist combination is associated with the least effective strategy and that rivaroxaban and apixaban may be associated with the lowest risk for bleeding.

Availability of medical and endovascular therapies for venous thromboembolism: a global survey for World Thrombosis Day.

BACKGROUND: Data on availability, affordability, and accessibility is key for the planning of global strategies to reduce the burden of venous thromboembolism (VTE). OBJECTIVES: A survey was conducted for the 10th anniversary of World Thrombosis Day to assess the availability of VTE therapies worldwide and challenges in uniform implementation. METHODS: We gathered information on the approval status, availability, utilization, occurrence of shortages, and spread of medical and interventional therapies for VTE. Furthermore, we collected information by accessing or contacting national or continental medicines agencies, manufacturers or distributors, and online drug repositories. RESULTS: We obtained data from a total of 69 countries: 33 countries in Europe, 19 in Asia, 7 in the Americas, 9 in Africa, and 1 in Oceania. Unfractionated heparin, low-molecular-weight heparin, and vitamin K antagonists were available in almost all countries, but shortages were recorded in 13%, 19%, and 15% of them, respectively. Direct oral anticoagulants were available in approximately three-quarters of the surveyed countries. At least one parenteral medication for heparin-induced thrombocytopenia was available in 57% of countries and a shortage was reported in 9% of these. Shortage of thrombolytics was recorded in 50% of countries. Overall, at least one type of catheter-directed therapy system was approved for use in 77% of countries and available in 23% of surveyed institutions. Our findings revealed notable geographic disparities in the worldwide availability of VTE therapies, the access to which appeared to be limited by economic and geopolitical factors. CONCLUSION: We anticipate that this comprehensive information will play a pivotal role in highlighting the shortcomings of VTE therapies and the lack of homogeneous availability globally.

Comparative Effectiveness and Safety of Apixaban and Rivaroxaban in Older Patients with Atrial Fibrillation: A Population-Based Cohort Study.

BACKGROUND: There are no clinical trials with head-to-head comparison between the two most commonly used oral anticoagulants (apixaban and rivaroxaban) in patients with atrial fibrillation (AF). The comparative efficacy and safety between these drugs remain unclear, especially among older patients who are at the highest risk for stroke and bleeding. OBJECTIVE: To compare the risk of major bleeding and thromboembolic events with apixaban versus rivaroxaban in older patients with AF. METHODS: We conducted a population-based, retrospective cohort study of all adult patients (66 years or older) with AF in Ontario, Canada who were treated with apixaban or rivaroxaban between April 1, 2011 and March 31, 2020. The primary safety outcome was major bleeding and the primary efficacy outcome was thromboembolic events. Secondary outcomes included any bleeding. Rates and hazard ratios (HRs) were adjusted for baseline comorbidities with inverse probability of treatment weighting (IPTW). RESULTS: This study included 42,617 patients with AF treated with apixaban and 30,725 patients treated with rivaroxaban. After IPTW using the propensity score, patients in the apixaban and rivaroxaban groups were well balanced for baseline values of demographics, comorbidities and medications; both groups had similar mean age of 77.4 years and 49.9% were female. At one year, the apixaban group had reduced risk for both major bleeding with an absolute risk reduction at one year of 1.1% (2.1% vs 3.2%; HR 0.65 [95% CI, 0.59-0.71]) and any bleeding (8.1% vs 10.9%; HR 0.73 [95% CI, 0.69-0.77]) with no difference in the risk for thromboembolic events (2.2% vs 2.2%; HR 1.02 [95% CI, 0.92-1.13]). CONCLUSIONS: Among AF patients, 66 years or older, treatment with apixaban was associated with reduced risk for major bleeding with no difference in risk for thromboembolic events compared with rivaroxaban.

Unmet needs and barriers in venous thromboembolism education and awareness among people living with cancer: a global survey.

BACKGROUND: Venous thromboembolism (VTE) is a major preventable cause of morbidity, disability, and mortality in subjects with cancer. A global appraisal of cancer-associated VTE education and awareness is not available. OBJECTIVES: To evaluate VTE-related education, awareness, and unmet needs from the perspective of people living with cancer using a quantitative and qualitative approach. METHODS: This cross-sectional study used data from an online-based survey covering multidimensional domains of cancer-associated VTE. Data are presented descriptively. Potential differences across participant subgroups were explored. RESULTS: Among 2262 patients with cancer from 42 countries worldwide, 55.3% received no VTE education throughout their cancer journey, and an additional 8.2% received education at the time of VTE diagnosis only, leading to 63.5% receiving no or inappropriately delayed education. When education was delivered, only 67.8% received instructions to seek medical attention in case of VTE suspicion, and 36.9% reported scarce understanding. One-third of participants (32.4%) felt psychologically distressed when becoming aware of the potential risks and implications connected with cancer-associated VTE. Most responders (78.8%) deemed VTE awareness highly relevant, but almost half expressed concerns about the quality of education received. While overall consistent, findings in selected survey domains appeared to numerically differ across age group, ethnicity, continent of residence, educational level, metastatic status, and VTE history. CONCLUSION: This study involving a large and diverse population of individuals living with cancer identifies important unmet needs in VTE-related education, awareness, and support across healthcare systems globally. These findings unveil multilevel opportunities to expedite patient-centered care in cancer-associated VTE prevention and management.

Optimizing antithrombotic therapy in patients with coexisting cardiovascular and gastrointestinal disease.

Balancing the safety and efficacy of antithrombotic agents in patients with gastrointestinal disorders is challenging because of the potential for interference with the absorption of antithrombotic drugs and for an increased risk of bleeding. In this Review, we address considerations for enteral antithrombotic therapy in patients with cardiovascular disease and gastrointestinal comorbidities. For those with gastrointestinal bleeding (GIB), we summarize a general scheme for risk stratification and clinical evidence on risk reduction approaches, such as limiting the use of concomitant medications that increase the risk of GIB and the potential utility of gastrointestinal protection strategies (such as proton pump inhibitors or histamine type 2 receptor antagonists). Furthermore, we summarize the best available evidence and potential gaps in our knowledge on tailoring antithrombotic therapy in patients with active or recent GIB and in those at high risk of GIB but without active or recent GIB. Finally, we review the recommendations provided by major medical societies, highlighting the crucial role of teamwork and multidisciplinary discussions to customize the antithrombotic regimen in patients with coexisting cardiovascular and gastrointestinal diseases.

Heparin Dose Intensity and Organ Support-Free Days in Patients Hospitalized for COVID-19.

Background: Clinical trials suggest that therapeutic-dose heparin may prevent critical illness and vascular complications due to COVID-19, but knowledge gaps exist regarding the efficacy of therapeutic heparin including its comparative effect relative to intermediate-dose anticoagulation. Objectives: The authors performed 2 complementary secondary analyses of a completed randomized clinical trial: 1) a prespecified per-protocol analysis; and 2) an exploratory dose-based analysis to compare the effect of therapeutic-dose heparin with low- and intermediate-dose heparin. Methods: Patients who received initial anticoagulation dosed consistently with randomization were included. The primary outcome was organ support-free days (OSFDs), a combination of in-hospital death and days free of organ support through day 21. Results: Among 2,860 participants, 1,761 (92.8%) noncritically ill and 857 (89.1%) critically ill patients were treated per-protocol. Among noncritically ill per-protocol patients, the posterior probability that therapeutic-dose heparin improved OSFDs as compared with usual care was 99.3% (median adjusted OR: 1.36; 95% credible interval [CrI]: 1.07-1.74). Therapeutic heparin had a high posterior probability of efficacy relative to both low- (94.6%; adjusted OR: 1.26; 95% CrI: 0.95-1.64) and intermediate- (99.8%; adjusted OR: 1.80; 95% CrI: 1.22-2.62) dose thromboprophylaxis. Among critically ill per-protocol patients, the posterior probability that therapeutic heparin improved outcomes was low. Conclusions: Among noncritically ill patients hospitalized for COVID-19 who were randomized to and initially received therapeutic-dose anticoagulation, heparin, compared with usual care, was associated with improved OSFDs, a combination of in-hospital death and days free of organ support. Therapeutic heparin appeared superior to both low- and intermediate-dose thromboprophylaxis.

DOAC-associated bleeding, hemostatic strategies, and thrombin generation assays - a review of the literature.

Direct oral anticoagulants (DOACs) account for most oral anticoagulant use. DOAC-associated bleeding events are commonly encountered in clinical practice and are associated with substantial morbidity and mortality. Both specific reversal agents and nonspecific hemostatic therapies, such as prothrombin complex concentrates, are used in the management of DOAC-associated bleeding. Measuring hemostatic efficacy and demonstrating a clinical impact from these therapies among studies of bleeding patients is challenging. Thrombin generation assays provide information on the total hemostatic potential of plasma, and have emerged as a promising modality to both measure the impact of DOACs on coagulation and to evaluate the effects of hemostatic therapies among patients with DOAC-associated bleeding. The mechanisms by which nonspecific hemostatic agents impact coagulation and thrombin generation in the context of DOAC therapy are unclear. As a result, we undertook a review of the literature using a systematic search strategy with the goal of summarizing the effects of DOACs on thrombin generation and the effects of both specific reversal agents and nonspecific hemostatic therapies on DOAC-altered thrombin generation parameters. We sought to identify clinical studies focusing on whether altered thrombin generation is associated with clinical bleeding and whether correction of altered thrombin generation parameters predicts improvements in clinical hemostasis. Lastly, we sought to outline future directions for the application of thrombin generation assays toward anticoagulation therapies and the question of anticoagulation reversal.

Effect of PCC on Thrombin Generation among Patients on Factor Xa Inhibitors with Major Bleeding or Needing Urgent Surgery (GAUGE): Design and Rationale.

Background Direct factor Xa inhibitors (FXaIs) account for most oral anticoagulant use and FXaI-associated bleeding events are common. Clinicians have variable national and regional access to specific FXaI reversal agents such as andexanet alfa. Many centers have adopted the use of prothrombin complex concentrates (PCCs) as hemostatic therapy for FXaI-associated major bleeding events. PCC does not impact circulating FXaI levels and its mechanism of action to achieve hemostasis in FXaI-associated bleeding is uncertain. While PCC increases quantitative thrombin generation assay (TGA) parameters, it does not correct FXaI-altered thrombin generation kinetics, nor does it normalize thrombin generation. Clinical data supporting the use of PCC are based on cohort studies reporting clinical hemostatic efficacy, which is difficult to measure. The benefits of PCC for FXaI-associated bleeding beyond supportive care are uncertain. Objective GAUGE is a prospective observational study designed to measure the effects of four-factor PCC administration (Octaplex) on TGA parameters among patients with FXaI-associated bleeding or needing urgent surgery. Methods Laboratory outcomes will include the mean paired change in TGA parameters from pre- to post-PCC administration and the proportion of participants whose post-PCC TGA values fall within a defined reference range. Clinical outcomes will include hemostatic efficacy, thromboembolic complications, and all-cause death at 30 days post-PCC. Conclusion Development of a viable and universally accessible FXaI bleed management strategy is crucial. GAUGE will provide in vivo data on the effects of PCC among patients with FXaI-associated bleeding.

Updated guidance for efficacy and safety outcomes for clinical trials in venous thromboembolism in children: communication from the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis.

Despite the growing number of pediatric antithrombotic clinical trials, standardized safety and efficacy outcome definitions for pediatric venous thromboembolism (VTE) clinical trials have not been updated since 2011. Many recent trials have adapted the recommended definitions, leading to heterogeneity in outcomes and limiting our ability to compare studies. The International Society on Thrombosis and Haemostasis Scientific and Standardization Subcommittee (SSC) on Pediatric and Neonatal Thrombosis and Hemostasis organized a Task Force to update the efficacy and safety outcome definitions for pediatric VTE clinical trials. The outcome definitions used in the recent pediatric antithrombotic trials, definitions recommended for adult studies, and regulatory guidelines were summarized and reviewed by the Task Force as the basis for this updated guidance. Major updates to the efficacy outcomes include the removal of VTE-related mortality as a part of a composite primary outcome and explicit inclusion of all deep venous anatomic sites. Safety outcomes were updated to include a new bleeding severity category: patient important bleeding, no intervention, which encompasses bleeding for which a patient seeks care but there is no change in management. Menstrual bleeding can now be included in any bleeding category when the criteria are met. We hope that these updated outcome definitions will allow the investigators to focus on clinically relevant and patient-important outcomes and provide standardization to facilitate continued high-quality evidence for the use of antithrombotic therapies in children.

Recommendation on the nomenclature for anticoagulants: updated communication from the International Society on Thrombosis and Haemostasis Scientific and Standardization Commitee on the Control of Anticoagulation.

Oral anticoagulation therapy has evolved beyond vitamin K antagonists to include oral direct thrombin inhibitors and factor Xa inhibitors. Collectively known as "direct oral anticoagulants," this class of medications represents the current standard of care for the prevention and treatment of common thrombotic disorders, including atrial fibrillation and venous thromboembolism. Medications that target factors XI/XIa and XII/XIIa are currently under investigation for several thrombotic and nonthrombotic conditions. Given that these emerging medications will likely have distinct risk-benefit profiles to the current direct oral anticoagulants, may have different routes of administration, and could be used for unique clinical conditions (e.g., hereditary angioedema), the International Society on Thrombosis and Haemostasis Subcommittee on Control of Anticoagulation assembled a writing group to make recommendations on the nomenclature of anticoagulant medications. With input from the broader thrombosis community, the writing group recommends that anticoagulant medications be described by the route of administration and specific targets (e.g., oral factor XIa inhibitor).

Thrombin generation, bleeding and hemostasis in humans: Protocol for a scoping review of the literature.

INTRODUCTION: Hemostasis and bleeding are difficult to measure. Thrombin generation assays (TGAs) can measure both procoagulant and anticoagulant contributions to coagulation. TGAs might prove useful for the study of bleeding disorders. There has been much progress in TGA methodology over the past two decades, but its clinical significance is uncertain. We will undertake a scoping review of the literature to synthesize available information on the application of TGAs towards the study of bleeding and hemostasis, TGA methodologies being used and to summarize available literature on associations between TGA parameters, bleeding and hemostatic outcomes. METHODS AND ANALYSIS: MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) will be searched in collaboration with an information specialist. Title/abstract and full-text screening will be carried out independently and in duplicate; eligible study types will include randomized controlled trials, non-randomized studies, systematic reviews, and case series reporting TGA results and bleeding/hemostatic outcomes among humans. Mapping the information identified will be carried out with results presented using qualitative data analytical techniques. ETHICS AND DISSEMINATION: This scoping review will use published, publicly available information. Research ethics approval will not be required. We will disseminate our findings using conference presentations, peer-reviewed publications, social media, and engagement with knowledge users. This review will outline knowledge gaps concerning TGAs, better delineate its applicability as a clinically relevant assay for bleeding. and seek to identify ongoing barriers to its widespread adoption in clinical research, and eventually, in the clinical setting. TRAIL REGULATIONS: Registration ID with Open Science Framework: osf.io/zp4ge.