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Many studies showing underuse of oral anticoagulants (OACs) in patients with atrial fibrillation (AF) predated the advent of the non-vitamin K antagonist OACs. We retrospectively examined use of OACs in a large commercially insured population. Administrative claims data from 4 research partners participating in FDA-Catalyst, a program of the Sentinel Initiative, were queried in September 2017. Patients were included if they were ≥30 years old with ≥365 days of medical/pharmacy coverage, and had ≥2 diagnosis codes for AF, a CHA2DS2-VASc score ≥2, absence of contraindications to OAC use, and no evidence of OAC use in the 365 days before the index AF diagnosis. The main outcome measures of the current analysis were rates of OAC use in the prior 12 months of cohort identification and factors associated with non-use. A total of 197,806 AF patients met the eligibility criteria prior to assessment of OAC treatment. Of these, 179,580 (91%) patients were ≥65 years old and 73,286 (37%) patients were ≥80 years old. Half of the patients (98,903) were randomized to the early intervention arm in the IMPACT-AFib trial and constitute the cohort for this analysis. Of these, 32,295 (33%) had no evidence of OAC use in the prior 12 months. Compared with patients with evidence of OAC use in the prior 12 months, patients without OAC use were more likely to be ≥80 years old, women, and have a history of anemia (51% vs 47%) and less likely to have diabetes (41% vs 44%), history of stroke or TIA (15% vs 19%), and history of heart failure (39% vs 48%). Despite a high risk of stroke, one-third of privately insured patients with AF and no obvious contraindications to an OAC were not treated with an OAC. There is an unmet need for evidence-based interventions that could lead to greater use of OACs in patients with AF at risk for stroke.

Atrial fibrillation (AF) is common, increasing as the population ages, and a major cause of embolic stroke. While oral anticoagulation (OAC) is highly effective at preventing stroke in patients with AF, it continues to be underused in eligible patients worldwide. The objective of this prospective, cluster randomized controlled trial (IMPACT-AF; ClinicalTrials.gov #NCT02082548) is to determine whether a comprehensive customized intervention will increase the rate and persistence of use of OAC in patients with AF. IMPACT-AF will be conducted in approximately 50 centers in 5 low- to middle-income countries. Before randomization, sites within countries will be paired to match in size, practice type and baseline rate of OAC use. Site pairs will be randomized to intervention versus control. In total, 40 to 70 patients with AF and at least 2 CHA2DS2-VASc risk factors will be enrolled at each site using a consecutive enrollment strategy, with the goal of capturing actual practice patterns. We aim for patients with a new diagnosis of AF to comprise at least 30% of the study cohort. Assuming an average baseline OAC use of 60% and a post-intervention use of 70% with a post-control rate of 60%, there will be roughly 94-98% power with 25 clusters per group (intracluster correlation coefficient of 0.02). While this trial focuses on improving treatment use and reducing preventable strokes, we also aim to better understand the reasons for OAC underuse. This will improve the intervention with the goal of creating educational recommendations to improve care for patients with AF.

The European medicinal leech has been used for medicinal purposes for millennia, and continues to be used today in modern hospital settings. Its utility is granted by the extremely potent anticoagulation factors that the leech secretes into the incision wound during feeding and, although a handful of studies have targeted certain anticoagulants, the full range of anticoagulation factors expressed by this species remains unknown. Here, we present the first draft genome of the European medicinal leech, Hirudo medicinalis , and estimate that we have sequenced between 79–94% of the full genome. Leveraging these data, we searched for anticoagulation factors across the genome of H. medicinalis . Following orthology determination through a series of BLAST searches, as well as phylogenetic analyses, we estimate that fully 15 different known anticoagulation factors are utilized by the species, and that 17 other proteins that have been linked to antihemostasis are also present in the genome. We underscore the utility of the draft genome for comparative studies of leeches and discuss our results in an evolutionary context.

The optimal long-term antithrombotic regimen for patients after successful catheter-based atrial fibrillation (AF) ablation is not well defined. Presently, practice variation exists, and the benefits of oral anticoagulation over antiplatelet therapy across the entire spectrum of stroke risk profile remain undefined in the postablation population. To date, there are no randomized trials to inform clinicians on this therapeutic question. The objective was to assess whether rivaroxaban is superior to acetylsalicylic acid (ASA) in reducing the risk of clinically overt stroke, systemic embolism, or covert stroke among patients without apparent recurrent atrial arrhythmias for at least 1 year after their most recent AF ablation procedure. A prospective, multicenter, open-label, randomized trial with blinded assessment of outcomes is under way (NCT02168829). Atrial fibrillation patients with at least 1 stroke risk factor (as defined by the CHA2DS2-VASc score) and without known atrial arrhythmia recurrences for at least 12 months after ablation are randomized to rivaroxaban 15 mg or ASA 75-160 mg daily. The primary outcome is a composite of clinically overt stroke, systemic embolism, and covert stroke based on brain magnetic resonance imaging. Key secondary outcomes include major bleeding outcomes, intracranial hemorrhage, transient ischemic attack, neuropsychological testing, quality of life, and an economic analysis. Subjects will be followed for 3 years. The estimated overall sample size is 1,572 subjects (786 per arm). The OCEAN trial is a multicenter randomized controlled trial evaluating 2 antithrombotic treatment strategies for patients with risk factors for stroke after apparently successful AF ablation. We hypothesize that rivaroxaban will reduce the occurrence of clinically overt stroke, systemic embolism, and covert stroke when compared with ASA alone.

ObjectiveTo evaluate efficacy and safety of oral anticoagulant regimens and aspirin for extended venous thromboembolism (VTE) treatment.MethodsWe searched MEDLINE, Embase, CENTRAL and conference proceedings for randomised controlled trials studying vitamin K antagonists (VKAs), direct oral anticoagulants (DOACs) or aspirin for secondary prevention of VTE beyond 3 months. ORs (95% credible intervals) between treatments were estimated using random-effects Bayesian network meta-analysis.ResultsSixteen studies, totaling more than 22 000 patients, were included. Compared with placebo or observation and with aspirin, respectively, the risk of recurrent VTE was lower with standard-intensity VKAs (0.15 (0.08 to 0.24) and 0.23 (0.09 to 0.54)), low-dose factor Xa inhibitors (0.16 (0.06 to 0.38) and 0.25 (0.09 to 0.66)), standard-dose factor Xa inhibitors (0.17 (0.08 to 0.33) and 0.27 (0.11 to 0.65)) and the direct thrombin inhibitor (0.15 (0.04 to 0.37) and 0.23 (0.06 to 0.74)) although the risk of major bleeding was higher with standard-intensity VKAs (4.42 (1.99 to 12.24) and 4.14 (1.17 to 18.86)). Effect estimates were consistent in male patients and those with index pulmonary embolism or with unprovoked VTE and in sensitivity analyses. In addition, compared with placebo or observation, the risk of all-cause mortality was reduced with standard-intensity VKAs (0.44 (0.20 to 0.87)) and low-dose factor Xa inhibitors (0.38 (0.12 to 0.995)).ConclusionsStandard-intensity VKAs and DOACs are more efficacious than aspirin for extended VTE treatment. Despite a higher risk of major bleeding, standard-intensity VKAs was associated with a lower risk of all-cause mortality. Since overall efficacy and safety of standard-intensity VKAs and DOACs are in equipoise, patient factors, costs and patient preferences should be considered when recommending extending anticoagulation treatment.

Many patients with atrial fibrillation (AF) and elevated stroke risk are not prescribed oral anticoagulation (OAC) despite evidence of benefit. Identification of factors associated with OAC non-prescription could lead to improvements in care. Using NCDR PINNACLE, a United States-based ambulatory cardiology registry, we examined factors associated with OAC non-prescription in patients with non-valvular AF at elevated stroke risk (CHA2DS2-VASc ≥2) between January 5, 2008 and December 31, 2014. Among 674,841 patients, 57% were treated with OAC (67% of whom were treated with warfarin). OAC prescription varied widely (28%-75%) across preselected strata of age, stroke risk (CHA2DS2-VASc), and bleeding risk (HAS-BLED), generally indicating that older patients at high stroke and low bleeding risk are commonly treated with OAC. Other factors associated with OAC non-prescription included reversible AF etiology; female sex; liver, renal, or vascular disease; and physician versus non-physician provider. Antiplatelet use was common (57%) and associated with the greatest risk of OAC non-prescription (odds ratio [OR] 4.44, 95% confidence interval [CI] 4.39–4.49). In this registry of AF patients, older patients at elevated stroke and low bleeding risk were commonly treated with OAC. However, a variety of factors were associated with OAC non-prescription. Specifically, antiplatelet use was prevalent and associated with the highest likelihood of OAC non-prescription. Future studies are warranted to understand provider and patient rationale that may underlie observed associations with OAC non-prescription.

Coronavirus disease 2019 (COVID-19) could predispose to both venous and arterial thromboembolism, in an exaggerated immune response to the virus, especially in severe patients. Even though aortic clots are a rare entity, the pro-coagulant nature of COVID-19 is associated with thrombosis in atypical locations and should be considered in patients with severe abnormalities in coagulation parameters. We describe a series of three cases of aortic thrombi diagnosed by computerized tomography (CT) angiography in patients with confirmed SARS-CoV-2 infection.

In patients with coronavirus disease 2019 (COVID-19), the prevalence of pre-existing cardiovascular diseases is elevated. Moreover, various features, also including pro-thrombotic status, further predispose these patients to increased risk of ischemic cardiovascular events. Thus, the identification of optimal antithrombotic strategies in terms of the risk–benefit ratio and outcome improvement in this setting is crucial. However, debated issues on antithrombotic therapies in patients with COVID-19 are multiple and relevant. In this article, we provide ten questions and answers on risk stratification and antiplatelet/anticoagulant treatments in patients at risk of/with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection based on the scientific evidence gathered during the pandemic.

Leeches (Annelida: Hirudinea) possess powerful salivary anticoagulants and, accordingly, are frequently employed in modern, authoritative medicine. Members of the almost exclusively marine family Piscicolidae account for 20% of leech species diversity, and they feed on host groups (e.g., sharks) not encountered by their freshwater and terrestrial counterparts. Moreover, some species of Ozobranchidae feed on endangered marine turtles and have been implicated as potential vectors for the tumor-associated turtle herpesvirus. In spite of their ecological importance and unique host associations, there is a distinct paucity of data regarding the salivary transcriptomes of either of these families. Using next-generation sequencing, we profiled transcribed, putative anticoagulants and other salivary bioactive compounds that have previously been linked to blood feeding from 7 piscicolid species (3 elasmobranch feeders; 4 non-cartilaginous fish feeders) and 1 ozobranchid species (2 samples). In total, 149 putative anticoagulants and bioactive loci were discovered in varying constellations throughout the different samples. The putative anticoagulants showed a broad spectrum of described antagonistic pathways, such as inhibition of factor Xa and platelet aggregation, which likely have similar bioactive roles in marine fish and turtles. A transcript with homology to ohanin, originally isolated from king cobras, was found in Cystobranchus vividus but is otherwise unknown from leeches. Estimation of selection pressures for the putative anticoagulants recovered evidence for both positive and purifying selection along several isolated branches in the gene trees, and positive selection was also estimated for a few select codons in a variety of marine species. Similarly, phylogenetic analyses of the amino acid sequences for several anticoagulants indicated divergent evolution.

The American College of Chest Physicians provides recommendations for the use of anticoagulant medications for several indications that are important in the primary care setting. Warfarin, a vitamin K antagonist, is recommended for the treatment of venous thromboembolism and for the prevention of stroke in persons with atrial fibrillation, atrial flutter, or valvular heart disease. When warfarin therapy is initiated for venous thromboembolism, it should be given the first day, along with a heparin product or fondaparinux. The heparin product or fondaparinux should be continued for at least five days and until the patient's international normalized ratio is at least 2.0 for two consecutive days. The international normalized ratio goal and duration of treatment with warfarin vary depending on indication and risk. Warfarin therapy should be stopped five days before major surgery and restarted 12 to 24 hours postoperatively. Bridging with low-molecular-weight heparin or other agents is based on balancing the risk of thromboembolism with the risk of bleeding. Increasingly, self-testing is an option for selected patients on warfarin therapy. The ninth edition of the American College of Chest Physicians guidelines, published in 2012, includes a discussion of anticoagulants that have gained approval from the U.S. Food and Drug Administration since publication of the eighth edition in 2008. Dabigatran and apixaban are indicated for the prevention of systemic embolism and stroke in persons with nonvalvular atrial fibrillation. Rivaroxaban is indicated for the prevention of deep venous thrombosis in patients undergoing knee or hip replacement surgery, for treatment of deep venous thrombosis and pulmonary embolism, for reducing the risk of recurrent deep venous thrombosis and pulmonary embolism after initial treatment, and for prevention of systemic embolism in patients with nonvalvular atrial fibrillation.