Direct Oral Anticoagulants Plasma Levels Measurement: Clinical Usefulness from Trials and Real-World Data

Predictors of Plasma Levels of Direct Oral Anticoagulants Among Patients with Atrial Fibrillation in Need of Elective Cardiac Procedures

BACKGROUND

The withdrawal timing of direct oral anticoagulants (DOACs) among patients in need of elective invasive surgery is based on DOAC pharmacokinetics in order to perform the procedure out of the DOAC peak plasma concentration. We aimed to investigate the prevalence and predictors of plasma levels of DOACs out of trough range in patients with atrial fibrillation (AF) in need of elective cardiac procedure.

MATERIALS AND METHODS

We evaluated all consecutive AF patients on DOAC therapy in need of elective cardiac procedure, admitted to our division from January 2022 to March 2022. All patients underwent DOAC plasma dosing the morning of procedure day. They were categorized as in range, above range, and below range, according to the DOAC reference range at the downstream point. The timing of discontinuation of DOAC therapy was considered as appropriate or not, according to the current recommendations. The clinical predictors of out-of-range DOAC plasma levels have been evaluated.

RESULTS

We included 90 consecutive AF patients (56.6% male, mean age 72.95 ± 10.12 years); 74 patients (82.22%) showed DOAC concentration out of the expected reference range. In half of them (n, 37), the DOAC plasma concentration was below the trough reference range. Of the study population, 17.7% received inappropriate DOAC dosages (10% overdosing, 7% underdosing), and 35.5% had incorrect timing of DOAC withdrawal (26% prolonged, 9.5% shortened). At multivariable analysis, inappropriate longer DOAC withdrawal period (OR 10.13; P ≤ 0.0001) and increased creatinine clearance (OR 1.01; P = 0.0095) were the independent predictors of plasma DOAC levels below the therapeutic trough range. In contrast, diabetes mellitus (OR 4.57; P = 0.001) was the only independent predictor of DOAC plasma level above the therapeutic trough range.

CONCLUSION

Increased creatinine clearance and inappropriate longer drug withdrawal period are the only independent predictors of DOAC plasma levels below the reference range; in contrast, diabetes is significantly correlated with DOAC plasma levels above the reference.

Comparing Safety and Efficacy of Direct Oral Anticoagulants Versus Warfarin in Extreme Obesity

Background: Limited clinical data exists regarding use of direct oral anticoagulants (DOACs) in extreme obesity, specifically those ≥140 kg or having a body mass index (BMI) ≥ 50 kg/m2. Objective: Evaluate the safety and efficacy of DOACs in extreme obesity. Patients/Methods: A retrospective chart review was performed at a single center of patients aged 18-89 years and weight ≥140 kg or BMI ≥50 kg/m2 receiving warfarin or DOAC therapy. Patients were followed for 1 year from prescribing/study inclusion. The primary outcome was the difference in rates of any bleed (composite of major, nonmajor clinically relevant, or minor bleeding events as defined by International Society of Thrombosis and Haemostasis (ISTH) criteria) between groups. Secondary outcomes included individual components of the composite primary outcome and effectiveness in preventing thrombotic events within 12 months. Post-hoc multivariate analysis evaluated potential predictors of bleeding events within overall patient population. Results: Two-hundred eighty-five patients were included, 80 and 205 in the DOAC and warfarin groups, respectively. Rates of any documented bleeding event were comparable in DOAC and warfarin groups (17.5% vs 17.1%, P > .05). No significant difference in rates of minor (P = .067), nonmajor clinically relevant (P = .825), and major (P = 1) bleeding events were observed. Two thrombotic events occurred in the warfarin group compared to none in the DOAC group. Increasing weight was associated with bleeding events in multivariate analysis. Conclusions: This data did not demonstrate a difference in safety or efficacy outcomes between DOACs and warfarin when utilized in patients with extreme obesity.

Direct oral anticoagulants or vitamin K antagonists in emergencies: comparison of management in an observational study

Background

Restoring hemostasis in patients on oral anticoagulants presenting with major hemorrhage (MH) or before surgical intervention has changed, with the replacement of vitamin K antagonist (VKA) with direct oral anticoagulants (DOACs).

Objectives

To observe the difference in urgent hemostatic management between patients on VKA and those on DOACs.

Methods

A multicenter observational study evaluated the variation in laboratory testing, hemostatic management, mortality, and hospital length of stay (LOS) in patients on VKA or DOACs presenting with MH or urgent hemostatic restoration.

Results

Of the 1194 patients analyzed, 783 had MH (61% VKA) and 411 required urgent hemostatic restoration before surgery (56% VKA). Compared to the international normalized ratio (97.6%), plasma DOAC levels were measured less frequently (<45%), and the time taken from admission for the coagulation sample to reach the laboratory varied widely (median, 52.3 minutes; IQR, 24.8-206.7). No significant plasma DOAC level (<50 ng/mL) was found in up to 19% of patients. There was a poor relationship between plasma DOAC level and the usage of a hemostatic agent. When compared with patients receiving VKA (96.5%) or dabigatran (93.7%), fewer patients prescribed a factor Xa inhibitor (75.5%) received a prohemostatic reversal agent. The overall 30-day mortality for MH (mean: 17.8%) and length of stay (LOS) (median: 8.7 days) was similar between VKA and DOAC patients.

Conclusion

In DOAC patients, when compared to those receiving VKA, plasma DOAC levels were measured less frequently than the international normalized ratio and had a poor relationship with administering a hemostatic reversal agent. In addition, following MH, mortality and LOS were similar between VKA and DOAC patients.

Antioxidant Properties of Oral Antithrombotic Therapies in Atherosclerotic Disease and Atrial Fibrillation

The thrombosis-related diseases are one of the leading causes of illness and death in the general population, and despite significant improvements in long-term survival due to remarkable advances in pharmacologic therapy, they continue to pose a tremendous burden on healthcare systems. The oxidative stress plays a role of pivotal importance in thrombosis pathophysiology. The anticoagulant and antiplatelet drugs commonly used in the management of thrombosis-related diseases show several pleiotropic effects, beyond the antithrombotic effects. The present review aims to describe the current evidence about the antioxidant effects of the oral antithrombotic therapies in patients with atherosclerotic disease and atrial fibrillation.

Clinical impact of oral anticoagulation among octogenarians with atrial fibrillation and anaemia

Our study aimed to describe the efficacy and safety of oral anticoagulation (OAC) use in elderly patients (> or = 80 years-old) with atrial fibrillation (AF) and concomitant anaemia. Data for this study were sourced from AF Research Database (NCT03760874). AF patients aged ≥ 80 who received OAC treatment, both direct oral anticoagulant (DOAC) and vitamin K antagonist (VKA) were selected. Participants were categorized as anaemic and non-anaemic. The primary outcome was the occurrence of overall bleeding. The primary effectiveness outcome was the occurrence of thromboembolic events (a composite of ischemic stroke, transient ischemic attack and systemic embolism). The secondary safety and effectiveness outcomes were major, minor bleedings and mortality, respectively. A total of 958 patients were included in the study, 120 (12.5%) were anaemic; among them, 93 patients (76.6%) were treated with VKAs and 28 (23.3%) with DOAC. Kaplan-Meier curves for major bleedings showed significant differences between anemic- and non-anemic groups (log-rank p = 0.005). In multivariate analysis, among patients on OAC, anaemia was independently associated with major bleeding (HR 2.36; 95% IC 1.2-4.4; p = 0.006), intracranial hemorrhages (HR 3.81; 95% IC 1.35-10.7; p = 0.01) and minor bleedings (HR 2.40; 95%IC 1.1-5.2; p = 0.02); these associations were not confirmed in the DOACs subgroup. No difference in survival was shown between anaemic- and non-anaemic groups and among anaemic patients, between DOAC and VKAs subgroups. Anaemic octogenarians with AF on OAC therapy showed a significantly increased risk of major bleedings, in particular ICH, and mortality compared to non-anaemic.

Gender Differences in Atrial Fibrillation: From the Thromboembolic Risk to the Anticoagulant Treatment Response

Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with an increased thromboembolic risk. The impact of the female sex as an independent risk factor for thromboembolic events in AF is still debated. Background and Objectives: The aim of this review is to evaluate the gender-related differences in cardioembolic risk and response to anticoagulants among AF patients. Materials and Methods: The PubMed database is used to review the reports about gender differences and thromboembolic risk in atrial fibrillation. Results: Non-vitamin K oral anticoagulants (NOACs) represent the gold standard for thromboembolic risk prevention in patients with non-valvular atrial fibrillation (NVAF). Despite a similar rate of stroke and systemic embolism (SE) among men and women in NOACs or vitamin K antagonists (VKAs) treatment, the use of NOACs in AF women is associated with a lower risk of intracranial bleeding, major bleeding, and all-cause mortality than in men. Conclusions: The female sex can be defined as a stroke risk modifier rather than a stroke risk factor since it mainly increases the thromboembolic risk in the presence of other risk factors. Further studies about the efficacy and safety profile of NOACs according to sex are needed to support clinicians in performing the most appropriate and tailored anticoagulant therapy, either in male or female AF patients.

Direct Oral Anticoagulants for Stroke Prevention in Special Populations: Beyond the Clinical Trials

Currently, direct oral anticoagulants (DOACs) are the first-line anticoagulant strategy in patients with non-valvular atrial fibrillation (NVAF). They are characterized by a more favorable pharmacological profile than warfarin, having demonstrated equal efficacy in stroke prevention and greater safety in terms of intracranial bleeding. The study population in the randomized trials of DOACs was highly selected, so the results of these trials cannot be extended to specific populations such as obese, elderly, frail, and cancer patients, which, on the other hand, are sub-populations widely represented in clinical practice. Furthermore, due to the negative results of DOAC administration in patients with mechanical heart valves, the available evidence in subjects with biological heart valves is still few and often controversial. We sought to review the available literature on the efficacy and safety of DOACs in elderly, obese, underweight, frail, cancer patients, and in patients with bioprosthetic heart valves with NVAF to clarify the best anticoagulant strategy in these special and poorly studied subpopulations.

The pharmacology of anticoagulant drug treatment options in COVID-19 patients: reviewing real-world evidence in clinical practice

INTRODUCTION

The optimal anticoagulation strategy for venous thromboembolism (VTE) prevention among COVID-19 patients, hospitalized or in the community setting, is still challenging and largely based on real-world evidence.

AREAS COVERED

We analyzed real-world data regarding the safety and effectiveness of anticoagulant treatment, both parenteral and oral, for VTE prevention or atrial fibrillation (AF)/VTE treatment among COVID-19 patients.

EXPERT OPINION

The efficacy of low-molecular-weight heparin (LMWH) doses for VTE prevention correlates with COVID-19 disease status. LMWH prophylactic dose may be useful in COVID-19 patients at the early stage of the disease. LMWH intermediate or therapeutic dose is recommended in COVID-19 patients with an advanced stage of the disease. COVID-19 patients on VKAs therapy for atrial fibrillation (AF) and VTE should switch to NOACs in the community setting or LMWH in the hospital setting. No definitive data on de-novo starting of NOACs or VKAs therapy for VTE prevention in COVID-19 outpatients are available. In patients at high risk discharged after hospitalization due to COVID-19, thromboprophylaxis with NOACs may be considered.

Put out the fire: The pleiotropic anti-inflammatory action of non-vitamin K oral anticoagulants

Non-vitamin K antagonist oral anticoagulants (NOACs) should be the preferred anticoagulant strategy for preventing ischemic stroke in patients with atrial fibrillation (AF) at increased thromboembolic risk and for treating deep venous thromboembolism (DVT) in the general population. Beyond their inhibiting action on the activated factor X (FXa) or thrombin (FIIa), NOACs showed some pleiotropic anti-inflammatory effects. The present review aimed to describe the role of FXa and FIIa in the inflammation pathway and the potential anti-inflammatory effects of NOACs.

Pharmacokinetic determinants for the right dose of antiarrhythmic drugs

INTRODUCTION

Antiarrhythmic drugs (AADs) show a narrow therapeutic range and marked intersubject variability in pharmacokinetics (PK), which may lead to inappropriate dosing and drug toxicity.

AREAS COVERED

The aim of the present review is to describe PK properties of AADs, discussing the main changes in different clinical scenarios, such as the elderly and patients with obese, chronic kidney, liver, and cardiac disease, in order to guide their right prescription in clinical practice.

EXPERT OPINION

There are few data about PK properties of AADs in a special population or challenging clinical setting. The use and dose of AADs is commonly based on physicians' clinical experience observing the clinical effects rather than being personalized on the individual patients PK profiles. More and updated studies are needed to validate a patient centered approach in the pharmacological treatment of arrhythmias based on patients' clinical features, including pharmacogenomics, and AAD pharmacokinetics.

Pharmacokinetics of Direct Oral Anticoagulants in Patients With Atrial Fibrillation and Extreme Obesity

PURPOSE

Direct oral anticoagulants (DOACs) are recommended in preference to vitamin K antagonists (VKAs) for stroke prevention in patients with atrial fibrillation (AF) eligible for oral anticoagulation therapy; however, data and clinical experiences supporting the use of DOACs in patients with a body mass index ≥40 kg/m² or weight >120 kg remain limited. The aim of this study was to evaluate the pharmacokinetic properties of DOACs in patients with AF and extreme obesity.

METHODS

We enrolled all consecutive patients with AF and extreme obesity undergoing treatment with DOACs followed up at Monaldi Hospital, Naples, Italy. To determine peak plasma and trough levels of DOACs, plasma samples were collected at 2nd, 4th, 6th, and 12th hours from the last dose intake in patients receiving apixaban and dabigatran and at the 2nd, 4th, 6th, and 24th hours in those receiving edoxaban and rivaroxaban. The DOACs' peak and trough plasma levels obtained from our study population were compared with those sourced from pharmacokinetic studies among patients without obesity, defined as a normal reference range in the literature. If at least 1 peak or trough plasma level was found ​​below or above the normal reference ranges, the patients were classified as having out-of-range DOAC plasma levels. Study population was then divided into in-range and out-of-range groups. Baseline characteristics, including DOAC treatment, were compared between the 2 groups. Univariate and multivariate logistic regression analysis were performed to identify baseline variables associated with DOACs' plasma concentration out of the expected range.

FINDINGS

A total of 58 patients (mean [SD] age, 70.93 [8.73] years; 40% female) with extreme obesity (mean [SD] body mass index. 44.43 [3.54] kg/m²) and AF while undergoing DOAC treatment were included in the present study. In 9 patients (15.5 %), the DOAC plasma concentrations were out of the expected ranges (out-of-range group);, indicating a greater likelihood of edoxaban 30 mg treatment (33% vs 2%; P < 0.01) and inappropriate DOAC underdosing (56% vs 4%; P < 0.005) compared with the in-range group. According to the multivariate logistic analysis (P = 0.0011), the inappropriate DOAC underdosing (hazard ratio = 29.37; P = 0.0002) was an independent predictor of DOAC plasma levels out of the expected ranges.

IMPLICATIONS

Patients with extreme obesity and AF who were receiving DOAC therapy had DOAC plasma concentrations in the expected range. The inappropriate DOAC underdosing seems to be the only independent clinical factor associated with a plasma concentration of the drug out of the expected range.