Laboratory Measurement of the Anticoagulant Activity of the Non–Vitamin K Oral Anticoagulants

AbstractBackgroundNon–vitamin K oral anticoagulants (NOACs) do not require routine laboratory monitoring. However, laboratory measurement may be desirable in special situations and populations.ObjectivesThis study’s objective was to systematically review and summarize current evidence regarding laboratory measurement of the anticoagulant activity of dabigatran, rivaroxaban, and apixaban.MethodsWe searched PubMed and Web of Science for studies that reported a relationship between drug levels of dabigatran, rivaroxaban, and apixaban and coagulation assay results. Study quality was evaluated using QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2).ResultsWe identified 17 eligible studies for dabigatran, 15 for rivaroxaban, and 4 for apixaban. For dabigatran, a normal thrombin time excludes clinically relevant drug concentrations. The activated partial thromboplastin time (APTT) and prothrombin time (PT) are less sensitive and may be normal at trough drug levels. The dilute thrombin time (R2 = 0.92 to 0.99) and ecarin-based assays (R2 = 0.92 to 1.00) show excellent linearity across on-therapy drug concentrations and may be used for drug quantification. For rivaroxaban and apixaban, anti-Xa activity is linear (R2 = 0.89 to 1.00) over a wide range of drug levels and may be used for drug quantification. Undetectable anti-Xa activity likely excludes clinically relevant drug concentrations. The PT is less sensitive (especially for apixaban); a normal PT may not exclude clinically relevant levels. The APTT demonstrates insufficient sensitivity and linearity for quantification.ConclusionsDabigatran, rivaroxaban, and apixaban exhibit variable effects on coagulation assays. Understanding these effects facilitates interpretation of test results in NOAC-treated patients. More information on the relationship between drug levels and clinical outcomes is needed

All-cause mortality after major gastrointestinal bleeding among patients receiving direct oral anticoagulants: a protocol for a systematic review and meta-analysis.

BACKGROUND Gastrointestinal (GI) bleeding represents the single most frequent site of anticoagulant-related bleeding. Adverse outcomes after major GI bleeding including mortality are not well characterized and, as a result, may be underappreciated in clinical practice. We aim to conduct a systematic review and meta-analysis of the risk for 30-day all-cause mortality after major GI bleeding among patients receiving DOACs. METHODS Electronic databases including MEDLINE, EMBASE, and Cochrane CENTRAL will be systematically searched to identify randomized controlled trials and prospective and retrospective cohort studies reporting 30-day all-cause mortality in adults with DOAC-related major GI bleeding. At least two investigators will independently perform study selection, risk of bias assessment, and data extraction. The proportion of deaths following a major GI event relative to the number of major GI bleeding events will be calculated for each individual study, and results across studies will be pooled using random-effects meta-analysis. We will assess risk of bias using criteria proposed by the GRADE group for prognostic studies. DISCUSSION The findings of this systematic review and meta-analysis will provide clinicians and patients with estimates of mortality after the most common major bleeding event to support shared decision making about anticoagulation management. TRIAL REGISTRATION PROSPERO CRD42022295815

Variations in incidence of venous thromboembolism in low-, middle-, and high-income countries

AimsTo examine the rates of venous thromboembolism (VTE) in high-income, upper middle-income, and lower middle/low-income countries (World Bank Classification).Methods and ResultsWe examined the rates of VTE in high-income, upper middle-income, and lower middle/low-income countries (World Bank Classification) in a cohort derived from four prospective international studies (PURE, HOPE-3, ORIGIN, and COMPASS). The primary outcome was a composite of pulmonary embolism, deep vein thrombosis, and thrombophlebitis. We calculated age- and sex-standardized incidence rates (per 1000 person-years) and used a Cox frailty model adjusted for covariates to examine associations between the incidence of VTE and country income level. A total of 215 307 individuals (1.5 million person-years of follow-up) from high-income (n = 60 403), upper middle-income (n = 42 066), and lower middle/low-income (n = 112 838) countries were included. The age- and sex-standardized incidence rates of VTE per 1000 person-years in high-, upper middle-, and lower middle/low-income countries were 0.87, 0.25, and 0.06, respectively. After adjusting for age, body mass index (BMI), smoking, antiplatelet therapy, anticoagulant therapy, education level, ethnicity, and incident cancer diagnosis or hospitalization, individuals from high-income and upper middle-income countries had a significantly higher risk of VTE than those from lower middle/low-income countries [hazard ratio (HR) 3.57, 95% confidence interval (CI) 2.40-5.30 and HR 2.27, 95% CI 1.59-3.23, respectively]. The effect of country income level on VTE risk was markedly stronger in people with a lower BMI, hypertension, diabetes, non-White ethnicity, and higher education.ConclusionThe rates of VTE are substantially higher in high-income than in low-income countries. The factors underlying the increased VTE risk in higher-income countries remain unknown.</div

Fabrication Principles and Their Contribution to the Superior In Vivo Therapeutic Efficacy of Nano-Liposomes Remote Loaded with Glucocorticoids

We report here the design, development and performance of a novel formulation of liposome- encapsulated glucocorticoids (GCs). A highly efficient (>90%) and stable GC encapsulation was obtained based on a transmembrane calcium acetate gradient driving the active accumulation of an amphipathic weak acid GC pro-drug into the intraliposome aqueous compartment, where it forms a GC-calcium precipitate. We demonstrate fabrication principles that derive from the physicochemical properties of the GC and the liposomal lipids, which play a crucial role in GC release rate and kinetics. These principles allow fabrication of formulations that exhibit either a fast, second-order (t1/2 ∼1 h), or a slow, zero-order release rate (t1/2 ∼ 50 h) kinetics. A high therapeutic efficacy was found in murine models of experimental autoimmune encephalomyelitis (EAE) and hematological malignancies

Synthetic data in cancer and cerebrovascular disease research: A novel approach to big data.

ObjectivesSynthetic datasets are artificially manufactured based on real health systems data but do not contain real patient information. We sought to validate the use of synthetic data in stroke and cancer research by conducting a comparison study of cancer patients with ischemic stroke to non-cancer patients with ischemic stroke.Designretrospective cohort study.SettingWe used synthetic data generated by MDClone and compared it to its original source data (i.e. real patient data from the Ottawa Hospital Data Warehouse).Outcome measuresWe compared key differences in demographics, treatment characteristics, length of stay, and costs between cancer patients with ischemic stroke and non-cancer patients with ischemic stroke. We used a binary, multivariable logistic regression model to identify risk factors for recurrent stroke in the cancer population.ResultsUsing synthetic data, we found cancer patients with ischemic stroke had a lower prevalence of hypertension (52.0% in the cancer cohort vs 57.7% in the non-cancer cohort, pConclusionWe demonstrated the utility of synthetic data in stroke and cancer research and provided key differences between cancer and non-cancer patients with ischemic stroke. Synthetic data is a powerful tool that can allow researchers to easily explore hypothesis generation, enable data sharing without privacy breaches, and ensure broad access to big data in a rapid, safe, and reliable fashion

Feature | Thrombosis and COVID-19: FAQs For Current Practice

An FAQ on the potential impact of COVID-19 on thrombotic and/or bleeding risk from ACC\u27s Science and Quality Committee summarize the current data on the risk, potential need for hemostasis/coagulation testing, VTE prophylaxis, and therapeutic anticoagulation in patients with COVID-19 without confirmed/suspected thrombosis

What are thrombosis risk and management considerations in COVID-19?

Principal Guidance: The apparent increased thrombotic risk in COVID-19 patients is sufficient to recommend pharmacological VTE prophylaxis in all hospitalized patients unless contraindicated; D-dimer levels may be valuable for clinical monitoring, but there is currently no evidence supporting its use to guide anticoagulation intensity beyond clinical judgment; post-discharge VTE prophylaxis with a DOAC should be considered