The non-vitamin K antagonist oral anticoagulants (NOACs) and extremes of body weight—a systematic literature review

Evaluating the safety and effectiveness of direct oral anticoagulants compared with warfarin in very elderly patients with atrial fibrillation with and without low bodyweight

BACKGROUND

Limited data exist on the safety and effectiveness of using direct oral anticoagulants (DOACs) in patients with atrial fibrillation aged 80 years or more with and without low bodyweight (LBW).

OBJECTIVES

We aimed to evaluate the safety and effectiveness of using DOACs in this population compared with warfarin.

METHODS

This retrospective active comparator new-user cohort study included veteran patients with atrial fibrillation who were newly initiated on either warfarin or DOACs between January 1, 2015, and January 1, 2021. The primary outcome was incidence of major bleeding and ischemic stroke. All outcomes were compared between treatment groups in 2 propensity score-matched cohorts of patients aged 80 years older with (AW) and without LBW (age-only cohort). Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs).

RESULTS

Matched AW and age-only cohorts included 493 and 11 909 patients, respectively, in each of the DOAC and warfarin exposure groups. Greater than 90% were male, with a mean age of ∼87 years. The rate of major bleeding was lower in the DOAC group compared with warfarin in both the AW (aHR, 0.63; 95% CI, 0.46-0.87) and age-only cohorts (aHR, 0.58; 95% CI, 0.49-0.77). A significantly lower rate of ischemic stroke occurred in the DOAC group compared with warfarin in the AW cohort (aHR, 0.62; 95% CI, 0.45-0.84) and age-only cohort (aHR, 0.63; 95% CI, 0.58-0.68).

CONCLUSION

DOAC use was associated with lower risk of major bleeding and ischemic stroke compared with warfarin in patients aged 80 years or older with and without LBW.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants in Low Body Weight Patients with Atrial Fibrillation: A Systematic Review and Meta-analysis

INTRODUCTION

Direct oral anticoagulant (DOAC) agents are established as the anticoagulation strategy of choice for a variety of clinical risks. Despite this, uncertainty still exists with regard to their efficacy and safety for the prevention of stroke and systemic embolism in some patient populations; most notably those with low body weight (LBW) (<60 kg or body mass index [BMI] <18 kg/m2). Currently, there is a paucity of trial and non-trial data to support a prescriptive recommendation for their use in these patient cohorts. We have carried out a pooled systematic review of the most up to date published data of patients stabilized on various DOAC analogs with the view to ascertaining the exact matrices of their efficacy and safety in these cohorts of patients.

METHODS

We initially carried out a comprehensive search of databases from inception to June 2023 for eligible studies exploring the efficacy and safety of various analogs of direct oral anticoagulants in patients with atrial fibrillation who had low body weight. Databases accessed include PubMed, EMBASE, the Science Citation Index, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effectiveness. We carried out a weighted comparison of derived pooled odd ratios (with their corresponding confidence intervals) of mortality outcomes between various DOACs using the random effects model.

RESULTS

Thirteen studies (n = 165,205 patients) were included in our meta-analysis. DOAC analogs were associated with increased stroke-related events, composite outcome, and mortality in low body weight patients compared to non-low body weight patients (odds ratio [OR] 1.50, 95% confidence interval [CI] 1.17-1.92), (OR 1.55, 95% CI 1.29-1.86), (OR 2.92, 95% CI 1.87-4.58), respectively. There was no significant difference in the safety outcome (major bleeding events) between the DOAC analogs (OR 1.19, 95% CI 0.93-1.52).

DISCUSSION

In this meta-analytical review comprising both real-world and randomized controlled studies, the use of DOAC analogs in low body weight patients (body weight of <60 kg or BMI<18 kg/m2) with atrial fibrillation was associated with increased risks of stroke-related events, composite outcomes, and mortality compared to non-low body weight cohorts patients. At the same time, there was no significant difference in terms of major bleeding events. This finding has provided the first resolution of pervading uncertainty surrounding the use of DOAC analogs in these patient cohorts and suggests the need for follow-up confirmatory systematic studies in this group of patients.

Association between Body Mass Index and Clinical Outcomes in Patients with Non-valvular Atrial Fibrillation Receiving Direct Oral Anticoagulants: A New Piece of Evidence on the Obesity Paradox from China

PURPOSE

We conducted a multicenter real-world study in China to assess the association between body mass index (BMI) and clinical outcomes in patients with atrial fibrillation (AF) taking direct oral anticoagulants (DOACs).

METHOD

This is a retrospective multicenter cohort study conducted in 15 centers in China. We collected demographic information through the hospital information system and obtained clinical events through follow-up visits to patients or relatives. Clinical outcomes include major, minor, total bleeding, thromboembolism, and all-cause death.

RESULT

A total of 6164 patients with non-valvular AF (NVAF) were included in this study. The incidence of major bleeding in patients with NVAF differed significantly by BMI category (P < 0.001), with 5.2% in the underweight group, 2.6% in the normal group, 1.4% in the overweight group, 1.1% in the obese I group, and 1.3% in the obese II group. There was no significant difference in minor, total bleeding, and thrombosis in the five groups (P = 0.493; P = 0.172; P = 0.663). All-cause death was significantly different among the five groups (P < 0.001), with 8.9% in the underweight group, 6.3% in the normal group, 4.8% in the overweight group, 2.2% in the obese I group, and 0.4% in the obese II group. High BMI was negatively associated with major bleeding (OR = 0.353, 95% CI 0.205-0.608), total bleeding (OR = 0.664, 95% CI 0.445-0.991), and all-cause death (OR = 0.370, 95% CI 0.260-0.527).

CONCLUSION

In patients with NVAF treated with DOACs, higher BMI was associated with lower major bleeding and better survival. BMI was a negative correlate of total bleeding, but not minor bleeding and thrombosis.

Adverse events in low versus normal body weight patients prescribed apixaban for atrial fibrillation

Safety and efficacy of direct oral anticoagulants (DOAC) in low weight patients with atrial fibrillation (AF) is unclear due to few low body weight patients enrolled in clinical trials. To assess bleeding and thrombotic event rates for patients with AF that are prescribed apixaban and have a low versus normal body weight. We analyzed patients with AF prescribed apixaban from 2017 to 2020 with at least 12 months of follow-up. Patients were divided into low [< 60 kg (kg)] and normal (60-100 kg) weight cohorts. Bleeding and thrombotic event rates were compared. Poisson regression and Cox proportional hazard models were used to estimate adjusted adverse event rates. A total of 545 patients met inclusion criteria. In the unadjusted analysis, there was an increase in non-major bleeding events requiring an Emergency Department visit more often in the low versus normal weight cohort (10.8 versus 7.4 per 100 patient-years, p = 0.15). Thrombotic event rates also occurred more often in the lower versus normal weight cohort (2.4 versus 0.9 per 100 patient-years, p = 0.09). However, adjusted analysis found no statistically significant difference in bleeding or thrombotic events between low and normal weight cohorts. The adjusted hazard ratio for bleeding was similar between the two weight cohorts. The use of apixaban in low body weight patients was not associated with higher rates of bleeding or thrombotic events, compared to those with normal body weight, after adjusting for potential confounding covariates. Larger studies may offer further insight into the overall safety and efficacy of DOAC therapy in these patients.

Fatal adverse events of rivaroxaban combined with aspirin: an analysis using data from VigiBase

Purpose

The aim of this study was to analyze the clinical characteristics of fatal adverse events (AEs) of rivaroxaban combined with aspirin and to underline the importance of the rational use of drugs.

Methods

The WHO global database of reported potential side effects of medicinal products (VigiBase) was searched for fatal AEs in the combined use of rivaroxaban and aspirin, and the clinical characteristics of those cases with sufficient information (vigiGrade completeness score ≥ 0.80) were analyzed.

Results

By January 19, 2020, 2309 fatal adverse event reports of rivaroxaban combined with aspirin from 21 countries were entered in VigiBase. One hundred and twenty cases contained further information, of which 42 were female (35%) and 78 were male (65%). The median age was 75 (range 34 to 93) years, and 109 cases (91%) were elderly patients (≥ 65 years). The AEs listed in the fatal case reports included bleeding in 114 cases (mainly intracranial hemorrhage and gastrointestinal hemorrhage, 59 and 46 respectively, accounting for 88%) and ischemic events in six cases (ischemic stroke in three, acute myocardial infarction in two, myocardial infarction combined with acute liver failure in one). Among the patients with bleeding events, 108 (95%) had existing risk factors for bleeding or for interacting with aspirin or rivaroxaban. These may be divided into the following: diseases (hypertension, renal impairment, history of stroke, peptic ulcer, or previous bleeding), drugs (high dose aspirin, antiplatelet drugs, anticoagulants, P-gp inhibitors/CYP3A4 inhibitors, non-steroidal anti-inflammatory drugs, steroids, and selective serotonin reuptake inhibitors), or other factors (e.g., elderly, low body weight, or excessive intake of ginger, fish oil, or alcohol). There were 45 cases with two or more of these risk factors in addition to rivaroxaban and aspirin. Patients with ischemic events are often in very high-risk groups of atherosclerotic cardiovascular disease (ASCVD) or self-discontinuation of treated drugs. Medication errors occurred in 24 patients (20%): excessive treatment in 17 cases, contraindication in three, frequency error in two, excessive treatment combined with contraindication in one, and self-discontinuation in one.

Conclusions

Fatal AEs related to rivaroxaban combined with aspirin, including bleeding and ischemic events, have been reported mostly in the elderly, and sometimes involved medication errors. The fatal AEs mainly manifested as serious bleeding, and most of them occurred in patients with concurrent multiple risk factors. Monitoring coagulation during rivaroxaban treatment is recommended in very high-risk ASCVD populations, and attention should be paid to prevention of medication errors.

Clinical Performance of Oral Anticoagulants in Elderly with Atrial Fibrillation and Low Body Weight: Insight into Italian Cohort of PREFER-AF and PREFER-AF Prolongation Registries

Background: Elderly patients are at high risk of both ischaemic and bleeding events, and the low body weight is considered a risk factor for major bleeding in atrial fibrillation (AF) patients on anticoagulation therapy. The aim of our study was to compare the safety and effectiveness of non-vitamin K antagonist oral anticoagulants (NOACs) versus well-controlled vitamin-K antagonists (VKA) therapy among AF patients aged >75 years and with a body weight <60 kg in a prospective registry setting. Methods: Data for this study were sourced from the Italian cohorts of PREFER in AF and PREFER in AF PROLONGATION registries. The occurrence of a composite of stroke, transient ischemic attack and systemic embolism (thromboembolic events) was the primary effectiveness endpoint. The occurrence of major bleeding was the primary safety endpoint. All-cause hospitalizations and all-cause death were the secondary endpoints. The net clinical benefit (NCB) was calculated in order to obtain an integrated assessment of the anti-thromboembolic and pro-haemorrhagic effects of NOACs vs. VKA. Results: Overall, 522 patients were included; 225 were on treatment with NOACs and 317 patients with VKA. The NOAC group more frequently featured a higher BMI and a higher prevalence of history of stroke/TIA and insulin-requiring diabetes; conversely, heart failure and chronic liver disease were less frequent in the NAOC group. In the unmatched study population, 18 patients (3.6% in the NOAC vs. 3.2% in the VKA group, p = 0.79) experienced thromboembolic events; 19 patients (1.78% in the NOAC vs. 4.73% in the VKA group, p = 0.06) experienced major bleeding events; and 68 patients were hospitalized during the follow-up (9.3% vs. 14.8%, p = 0.06). After balancing for potential confounders by using the 1:1 propensity score matching technique, 426 patients (213 on NOAC and 213 on VKA) were selected. We found no significant differences in terms of thromboembolic events (3.76% vs. 4.69%, p = 0.63), major bleeding events (n: 1.88% vs. 4.22%, p = 0.15) and hospitalizations (9.9% vs. 16.9%, p = 0.06) between NOAC vs. VKA matched population. Based on these incidences, we found a positive net clinical benefit (+1.6) of NOACs vs. VKAs. Conclusions: These real-world data suggest the safety and effectiveness of using NOACs in elderly patients with low body weight.

Expert Opinion on the Use of Novel Oral Anticoagulants for Stroke Prevention in Non-valvular Atrial Fibrillation for the Primary Care Setting in India: A Literature Review

Atrial fibrillation (AF), the most prevalent cardiac arrhythmia encountered in clinical practice, is linked with substantial morbidity and mortality due to accompanying risk of stroke and thromboembolism. Patients with AF are at a five-fold higher risk of suffering from a stroke. Anticoagulation therapy, with either vitamin K antagonists or novel oral anticoagulants (NOACs), is a standard approach to reduce the risk. Consultant physicians (CPs) in India are the primary point of contact for the majority of patients before they approach a specialist. The CPs may face challenges in screening and diagnosing AF patients. The apprehensions associated with managing AF patients with anticoagulants, further add to the challenges of a CP. This review aimed to identify the key decision points for the CPs to diagnose AF and initiate anticoagulation in patients with non-valvular AF (NVAF) and bring to the table a simplified recommendation supported by expert opinion and guidelines for stroke prevention in NVAF patients.

Direct oral anticoagulants in patients with nonvalvular atrial fibrillation and extreme body weight

BACKGROUND

Limited clinical data exist describing the use of direct oral anticoagulants (DOACs) in patient with extreme body weight. Thus, the International Society of Thrombosis and Haemostasis (ISTH) recommends avoiding DOACs in patients with weight >120 Kg, and on the contrary, no restrictions exist for underweight patients.

OBJECTIVE

To evaluate the effects of extreme body weight on DOAC activity and to compare the clinical outcomes of patients with an extreme body weight versus patients with a normal weight (61-119 Kg) treated with DOACs.

METHODS

Single tertiary care Italian centre multidisciplinary registry including nonvalvular atrial fibrillation (NVAF) patients treated with DOACs. Based on weight, three subcohorts were defined: (i) underweight patients (≤60 Kg); (ii) patients with a normal weight (61-119 Kg, as control group); and (iii) overweight patients (≥120 Kg). Primary efficacy endpoint was 2-year rate of thromboembolic events. Primary safety endpoint was 2-year rate of major bleeding. Event-free survival curves among groups were compared using Cox-Mantel test.

RESULTS

812 NVAF patients were included, 108 patients weighed ≤60 Kg (13%, underweight), 688 weighed between 61 and 119 Kg (85%, normal weight), and 16 weighed ≥120 Kg (2%, overweight). In particular, among underweight patients, dabigatran was prescribed in 26% patients, apixaban in 27%, rivaroxaban in 28% and edoxaban in 22% ones. Instead, among overweight patients, 44% were treated with dabigatran, 25% with apixaban, 25% with rivaroxaban and 4% with edoxaban. Underweight patients were older, more frequently women, with lower creatinine clearance and a history of previous strokes, resulting in higher CHA2DS2-VASc score than in both remaining groups. Up to 2 years, no statistically significant difference was observed between the three groups of weight for thromboembolic events (P = .765) and for overall bleeding (P = .125), but a trend towards decreased overall bleeding rates was noticed as weight increased (24.1% vs 16.7% vs 12.5%, respectively).

CONCLUSION

In this tertiary care centre registry, 15% of patients treated with DOACs presented an extreme weight. Compared to patients with a normal weight, no significant rates of thromboembolic events were observed for underweight or overweight patients. A trend towards decreased overall bleeding frequency as weight increased was highlighted up to 2 years. The present results should be considered as preliminary and hypothesis generating.

Real life behaviour of direct oral anticoagulants in patients with nonvalvular atrial fibrillation and morbid obesity

Atrial fibrillation (AF) is the most prevalent arrhythmia worldwide and the main cause of anticoagulation, being direct oral anticoagulants (DOAC) increasingly used in this context. On the other hand, obesity is a known risk thromboembolic factor. In the clinical trials that led to the approval of DOAC for ischemic stroke prevention, patients with morbid obesity were underrepresented. The International Society of Thrombosis and Haemostasis suggests not using these drugs in morbid obese patients. Thus, the primary objectives of this study were to analyse the rates of mortality, thrombotic and haemorrhagic events in patients with morbid obesity. As secondary objectives, factors statistically associated with these events were analysed. Methods: multicentre retrospective study that included patients diagnosed with AF on treatment with DOAC from January 2013 to December 2016. The subgroup of patients with morbid obesity (BMI > 40 and / or weight > 120 kg) was analysed. Mean follow-up was 1.7 years. Results: Amongst 2,492 patients included in the study, 135 patients had morbid obesity (mean age was 71 ± 11 years). The mean scores of the CHA2DS2-VASc and HAS-BLED risk scales were 3.7 ± 1.6 and 2.2 ± 0.9, respectively. Neither differences were found regarding mortality (5.2 vs 6/100 patient-years, p = 0.662), ischemic stroke (0.8 vs 1.9/100 patient-years, p = 0.261) and major bleeding rates (3 vs 3.1/100 patient-years, p = 0.983) between morbidly obese population and general population. Nor was there an association found between the degree of obesity and any of the events studied. Conclusion: DOAC are safe and effective in morbidly obese patients.

2021 Focused update of the 2017 consensus guidelines of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation

The consensus of the Asia Pacific Heart Rhythm Society (APHRS) on stroke prevention in atrial fibrillation (AF) has been published in 2017 which provided useful clinical guidance for cardiologists, neurologists, geriatricians, and general practitioners in Asia-Pacific region. In these years, many important new data regarding stroke prevention in AF were reported. The Practice Guidelines subcommittee members comprehensively reviewed updated information on stroke prevention in AF, and summarized them in this 2021 focused update of the 2017 consensus guidelines of the APHRS on stroke prevention in AF. We highlighted and focused on several issues, including the importance of AF Better Care (ABC) pathway, the advantages of non-vitamin K antagonist oral anticoagulants (NOACs) for Asians, the considerations of use of NOACs for Asian patients with AF with single 1 stroke risk factor beyond gender, the role of lifestyle factors on stroke risk, the use of oral anticoagulants during the "coronavirus disease 2019" (COVID-19) pandemic, etc. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician's decision remains the most important factor in the management of AF.

Eighty years of oral anticoagulation: Learning from history

In the year 2021 we celebrate the 80th anniversary of the first clinical use of vitamin K antagonists (VKAs), the mainstay of prevention and long-term treatment of thromboembolic disease. The discovery and development of oral anticoagulants is one of the most important chapters in the history of medicine, a goal pursued by physicians trying to combat the clinical manifestations of thrombosis since ancient times. Until the last decade, VKAs were the only oral anticoagulants available and used in clinical practice. Today, their clinical use has progressively shrunk, as the non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly replacing VKAs in various conditions after the successful completion of several large randomized controlled trials. Currently, new research is tackling upstream components of the intrinsic pathway - particularly factor XI and factor XII - for the development of new, even safer anticoagulants promising to reduce bleeding without compromising efficacy. This review highlights the evolution of oral anticoagulant therapy tracing the key stages of a long and fascinating history that has unfolded from the first part of the twentieth century until today, indeed an intriguing journey where serendipity is intertwined with the tenacious work of many researchers.

Severe gastrointestinal bleeding in patients with atrial fibrillation receiving oral anticoagulants (based on REGistry of long-term AnTithrombotic TherApy – REGATTA)

Background. The rate of major bleeding in patients with atrial fibrillation receiving oral anticoagulants is 25% per year. Gastrointestinal bleedings are at least a half of major hemorrhagic complications. Currently, there is no optimal scale to calculate the risk of bleeding, and therefore the search for clinical predictors of gastrointestinal bleeding remains relevant. Aim. To assess the frequency and structure of large gastrointestinal bleeding, as well as to identify clinical predictors of their development based on long-term prospective observation of patients with atrial fibrillation receiving oral anticoagulants. Materials and methods. Data were obtained from single center prospective REGistry of long-term AnTithrombotic TherApy (REGATTA NCT043447187). Investigation based on a 20-year follow-up with 510 patients with atrial fibrillation with a high thromboembolic risk (median CHA2DS2-VASc was 4 points). The REGATTA registry assessed the frequency and structure of major gastrointestinal bleeding. Predictors of the development of 32 large gastrointestinal bleeding were identified based on the analysis of pairs with univariate and multivariate analyses. Results. The frequency of major gastrointestinal bleeding in patients with atrial fibrillation receiving oral anticoagulants at 1 year was 1.42 per 100 patients; the predominant localization was upper gastrointestinal tract. Predictors of the development of major gastrointestinal bleeding according to multiple regression data analysis were hemoglobin level 14.55 g/dL, body mass index 28.4 kg/m2, gastrointestinal ulcer or erosive lesion and major hemorrhagic complications in history of disease. In 1/2 cases the sourse of bleeding remained unclear. Conclusion. Searching for clinical predictors of gastrointestinal bleeding can identify patients receiving oral anticoagulants who is need of intensive monitoring risk factors to prevent the development of life-threatening bleeding and to provide with adequate anticoagulant therapy.

Impact of Weight on Clinical Outcomes of Edoxaban Therapy in Atrial Fibrillation Patients Included in the ETNA-AF-Europe Registry

BACKGROUND

Extremes of body weight may alter exposure to non-vitamin K antagonist oral anticoagulants and thereby impact clinical outcomes. This ETNA-AF-Europe sub-analysis assessed 1-year outcomes in routine care patients with atrial fibrillation across a range of body weight groups treated with edoxaban.

METHODS

ETNA-AF-Europe is a multinational, multicentre, observational study conducted in 825 sites in 10 European countries. Overall, 1310, 5565, 4346 and 1446 enrolled patients were categorised into ≤60 kg, >60-≤80 kg (reference weight group), >80-≤100 kg and >100 kg groups.

RESULTS

Patients weighing ≤60 kg were older, more frail and had a higher CHA2DS2-VASc score vs. the other weight groups. The rates of stroke/systemic embolism, major bleeding and ICH were low at 1 year (0.82, 1.05 and 0.24%/year), with no significant differences among weight groups. The annualised event rates of all-cause death were 3.50%/year in the overall population. After adjustment for eGFR and CHA2DS2-VASc score, the risk of all-cause death was significantly higher in extreme weight groups vs. the reference group.

CONCLUSIONS

Low rates of stroke and bleeding were reported with edoxaban, independent of weight. The risk of all-cause death was higher in extremes of weight vs. the reference group after adjustment for important risk modifiers, thus no obesity paradox was observed.

Real-world effectiveness and safety of rivaroxaban versus warfarin among non-valvular atrial fibrillation patients with obesity in a US population

OBJECTIVES

Current evidence indicates that the pharmacokinetic profile of rivaroxaban is not significantly impacted by body weight. However, real-world data are needed to better assess the potential clinical benefits and risks associated with rivaroxaban in non-valvular atrial fibrillation (NVAF) patients with obesity. Thus, our objectives were to assess the real-world effectiveness and safety of rivaroxaban versus warfarin among NVAF patients with obesity in the US nationally representative commercially-insured population.

METHODS

Health insurance claims data from the IQVIA PharMetrics Plus database (January 2010-September 2019) were used to identify NVAF patients with obesity (based on diagnosis codes) initiated on rivaroxaban or warfarin. Inverse probability of treatment weighting (IPTW) was used to adjust for imbalances between groups. Study outcomes of interest were evaluated up to 36 months post-treatment initiation and included the composite of stroke or systemic embolism (stroke/SE) and major bleeding. Outcomes were compared using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

A total of 10,555 patients were initiated on rivaroxaban and 5080 patients on warfarin. Following IPTW, the risk of stroke/SE was 26% lower among patients prescribed rivaroxaban relative to warfarin (HR: 0.74, 95% CI: 0.60, 0.91, p = .004) at 36 months. Rivaroxaban-initiated patients had a risk of major bleeding similar to that of warfarin-initiated patients (HR: 0.85, 95% CI: 0.71, 1.02, p = .085).

CONCLUSIONS

These results suggest that rivaroxaban is an effective and safe treatment option among NVAF patients with obesity in a commercially-insured US population.

Direct-Acting Oral Anticoagulants in Atrial Fibrillation: What's New in the Literature

Atrial fibrillation (AF) is considered the most common sustained cardiac arrhythmia, and it is associated with a significant risk of adverse events, especially ischemic stroke. Oral anticoagulation is the cornerstone for stroke prevention in AF; for many years, only vitamin K antagonists were used for this purpose, with an absolute risk reduction >60%. However, these agents have limitations, such as narrow therapeutic margins and drug-food and drug-drug interactions. More recently, 4 direct-acting oral anticoagulants (DOACs)-non-vitamin K antagonists-have become available for patients with AF: dabigatran, rivaroxaban, apixaban, and edoxaban. In addition to a comparable efficacy to warfarin in large randomized controlled trials, DOACs were found to promote a lower risk of intracranial bleeding. The strategic dosage and lack of need for periodic prothrombin-time testing make their use attractive, especially for primary or secondary prevention of stroke in older adults. Furthermore, among patients with AF presenting with acute coronary syndrome or undergoing percutaneous coronary intervention, apixaban is associated with a reduction in serious bleeding events when compared with warfarin. On the other hand, there is no evidence of benefit of DOACs in patients with mechanical prosthetic valves or moderate/severe mitral stenosis. Furthermore, the suitability of DOACs in patients with liver disease is still poorly understood, and their safety in patients requiring renal replacement therapy remains uncertain. This review provides an overview of the main trials of DOACs, their pharmacology and safety profile, clinical implications, and best indications in light of the current evidence.

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

Measurement of direct oral anticoagulants (DOACs) activity is not routinely necessary. Indeed, evaluation of DOACs plasmatic concentration is discouraged for the majority of patients, due to the lack of outcome data supporting this approach. Nevertheless, DOAC measurements may be useful in emergency situations such as serious bleeding events, need for urgent invasive procedures, and acute ischemic stroke or in managing anticoagulation in "special populations" not adequately studied in clinical trials, for example the very elderly or those at the extremes of body weight. The aim of this review is to describe and summarize the methods for DOACs activity evaluation and the settings in which their plasma level measurement may be indicated, analyzing indications from scientific societies and evidence from clinical trials, as well as real world data on the usefulness of DOACs plasma levels "monitoring."

Direct Oral Anticoagulants in the Treatment of Venous Thromboembolism: Use in Patients with Advanced Renal Impairment, Obesity, or Other Weight-Related Special Populations

There are currently more than 7 million patients taking a direct oral anticoagulant (DOAC), with more new prescriptions per year than warfarin. Despite impressive efficacy and safety data for the treatment of venous thromboembolism, patients with obesity or advanced renal impairment represented a small portion of the patients enrolled in the phase 3 clinical trials. Therefore, to evaluate the potential use of DOACs in these special populations, clinicians need to have an understanding of the pharmacokinetics and pharmacodynamics of these agents in these settings. Since data from randomized controlled trials are limited, data from observational trials are helpful in gaining comfort with the use of DOACs in these special populations. Selecting the appropriate dose for each agent is imperative in achieving optimal patient outcomes. We provide an extensive review of the pharmacokinetics, pharmacodynamics, phase 3 clinical trials, and observational studies on the use of DOACs in patients with advanced renal impairment, obesity, or other weight-related special populations to provide clinicians with a comprehensive understanding of the data for optimal drug and dose selection.

Direct Oral Anticoagulants in Atrial Fibrillation: Practical Considerations and Remaining Issues

Preventing thromboembolic events, while minimizing bleeding risks, remains challenging when managing patients with atrial fibrillation. Despite large and successful trial programs, several clinical concerns remain which commonly relate to fears of over- or underexposure to drugs and unfavorable outcomes. After a short summary of the main phase III trial findings, this short review discusses the evidence and clinical relevance of common clinical concerns (correct direct oral anticoagulant [DOAC] dosing; DOAC in moderate-to-severe renal impairment; and the relevance of fasting, nasogastric tube feeding, or high body mass index) on DOAC plasma levels. Finally, the need for specific DOAC antidotes will be addressed.

Direct oral anticoagulants in the treatment of acute venous thromboembolism in patients with obesity: A systematic review with meta-analysis

BACKGROUND

Direct oral anticoagulants' (DOAC) pharmacokinetics are affected by obesity. Their efficacy and safety in obesity (BMI≥30 kg/m²) and morbid obesity (BMI≥40 kg/m²) are still unclear in the treatment of venous thromboembolism (VTE).

OBJECTIVES

To compare the efficacy/safety of DOAC versus vitamin K antagonist (VKA)/low molecular weight heparin (LMWH) for the treatment of VTE in patients with obesity and morbid obesity. The primary efficacy/safety outcomes were VTE recurrence and major bleeding (MB). Clinically relevant non-MB and mortality were also evaluated.

METHODS

A systematic literature search (MEDLINE, EMBASE, CENTRAL, Web of Science) identified studies evaluating DOAC in the treatment of VTE in patients with obesity and reporting one of the outcomes. Relative risks (RR) and 95 % confidence intervals (CI) were estimated using the Mantel-Haenszel method.

RESULTS

We included 21 studies (50,360pts) of which 16,150 patients had a BMI≥30 kg/m² and 6443 patients had a BMI≥40 kg/m². VTE recurrence was similar with DOAC compared to VKA/LMWH in patients with obesity (RR 1.03;95 %CI 0.93-1.15;p = 0.55) and morbid obesity (RR 1.06;95 %CI 0.94-1.19;p = 0.35). DOAC were also associated with a reduction in MB (RR 0.57;95 %CI 0.34-0.94;p = 0.03 and RR 0.71;95 %CI 0.50-1.00;p = 0.05 in patients with obesity and morbid obesity, respectively). Subgroup analyses comparing randomized controlled trials to observational studies showed consistent results. No difference was observed in regards of clinically relevant non-MB and mortality.

CONCLUSION

There is no signal for differences in VTE recurrence in patients with obesity and morbid obesity treated with DOAC compared to VKA/LMWH, while DOAC likely reduce the risk of MB compared to VKA/LMWH.

Non-vitamin K vs vitamin K oral anticoagulants in patients aged > 80 year with atrial fibrillation and low body weight

BACKGROUND

Octogenarian patients are at high risk of both ischaemic and bleeding events, and the low body weight is considered a risk factor for major bleeding in atrial fibrillation (AF) patients on anticoagulation therapy. The aim of our study was to compare the safety and effectiveness of NOACs versus well-controlled VKA therapy among patients aged > 80 year with AF and low body weight in real-life setting.

METHODS

Data for this study were sourced from the multicenter prospectively maintained Atrial Fibrillation Research Database (NCT03760874). From this, we selected AF patients aged ≥ 80 years and weighted ≤ 60 kg who received NOACs or VKAs treatment (only those with a time in therapeutic range > 70%). 279 patients (136 in NOAC group and 143 in VKA group) were selected.

RESULTS

A total of 71 patients (17 in NOAC vs 54 in VKA group) died during the follow-up. The incidence rate of all-cause mortality was 27.70 per 100 person-years (14.91 in NOAC vs 37.94 in VKA group, adjusted hazard ratio 0.43; 95% CI 0.25 to 0.975; P = .003). 22 patients (9 in NOAC vs 13 in VKA group, P = .6) had major bleeding events. Diabetes mellitus, COPD and age resulted positively associated with death, whereas NOACs, parossistic AF and weight negatively associated with mortality.

CONCLUSIONS

Our real-world data might suggest the safe and efficacy use of NOACs in this setting of population, justified by a reduction in overall mortality over VKAs. Further studies are needed to confirm these data.

Comparison of Dabigatran Plus a P2Y12 Inhibitor With Warfarin-Based Triple Therapy Across Body Mass Index in RE-DUAL PCI

BACKGROUND

Body mass index (BMI) affects drug levels of nonvitamin K antagonist oral anticoagulants. We sought to assess whether BMI affected outcomes in the RE-DUAL PCI trial.

METHODS

RE-DUAL PCI (NCT02164864) evaluated the safety and efficacy of a dual-antithrombotic-therapy regimen using dabigatran (110 mg or 150 mg twice daily and a P2Y₁₂ platelet antagonist) in comparison with triple therapy of warfarin, aspirin, and a P2Y₁₂ platelet inhibitor in 2725 patients with atrial fibrillation who had undergone percutaneous coronary intervention (PCI). We compared the risk of first International Society on Thrombosis and Haemostasis (ISTH)-defined major or clinically relevant nonmajor bleeding events (primary endpoint) and the composite of death, myocardial infarction, stroke, systemic embolism, or unplanned revascularization (main efficacy endpoint) in relation to baseline BMI.

RESULTS

Median (range) BMI was 28.1 (14-66) kg/m². Dabigatran dual therapy versus warfarin triple therapy had relevantly and similarly lower rates of bleeding at both 110 mg and 150 mg twice-daily doses, irrespective of BMI. Thromboembolic event rates appeared consistent across categories of BMI, including those <25 and ≥35 kg/m² (P for interaction: 0.806 and 0.279, respectively).

CONCLUSIONS

The reduction in bleeding with dabigatran dual therapy compared with warfarin triple therapy in patients here evaluated appears consistent across BMI categories.

Clinical Performance of Nonvitamin K Antagonist Oral Anticoagulants in Real-World Obese Patients with Atrial Fibrillation

The prevalence of both atrial fibrillation (AF) and obesity has steadily increased. Nonvitamin K antagonist oral anticoagulants (NOACs) have been shown to be more effective and safer than vitamin K antagonists (VKAs) for long-term stroke prevention in patients with nonvalvular AF. There are still limited data in the literature regarding performance of NOACs in obese patients with AF in the “real world.” The aim of our study was to compare the safety and effectiveness of NOACs versus well-controlled VKA therapy in obese AF patients in a “real-world” setting. Here, we have considered patients with AF and obesity (body mass index [BMI] > 30 kg/m2) on NOAC or VKA therapy included in the multicenter Atrial Fibrillation Research Database (NCT03760874). The occurrence of major bleedings (MBs) and thromboembolic events (composite of ischemic stroke, transient ischemic attack, and systemic embolism) was respectively considered primary safety and effectiveness outcomes. We identified 1,047 AF patients with obesity who received NOAC (n = 272) or VKA (n = 775) treatment. After propensity score matching analysis, 248 NOAC and 496 VKA recipients with similar clinical characteristics, including BMI (34.8 ± 3.4 in NOAC vs. 35.1 ± 3.8 in the VKA group; p = 0.50), were evaluated. The mean follow-up was 39 ± 7 months. The incidence rate of thromboembolic events was 1.10 per 100 person-years (0.67 in NOAC vs. 1.28 in the VKA group; hazard ratio [HR]: 0.52; 95% confidence interval [CI]: 0.22–1.22; p = 0.19). The incidence rate of MB was 1.9 per 100 person-years (1.1 in NOAC vs. 2.28 in the VKA group; HR: 0.46; 95% CI: 0.24–0.88; p = 0.04). The incidence rate of intracranial hemorrhage was 0.4 per 100 person-years (0.27 in NOAC vs. 0.47 in the VKA group; HR: 0.57; 95% CI: 0.12–2.73; p = 0.48). A positive net clinical benefit (NCB) of NOACs over VKAs was found (+0.91). Presence of anemia (HR: 1.75; p = 0.003) and concomitant use of antiplatelet drugs (HR: 2.41; p = 0.001) were found to be independent predictors of MB; moreover, age (HR: 1.65; p = 0.003) was an independent predictor of thromboembolic events. Our data support the hypothesis of safe and effective use of NOACs in patients with AF and obesity, justified by a statistically significant lower incidence of MB and a favorable NCB over VKAs.

Edoxaban versus Warfarin in Patients with Atrial Fibrillation at the Extremes of Body Weight: An Analysis from the ENGAGE AF-TIMI 48 Trial

BACKGROUND

 The effects of anticoagulants at extremes of body weight (BW) are not well described. The aim of this study was to analyze the pharmacokinetics/pharmacodynamics and clinical outcomes in patients randomized to warfarin, higher dose edoxaban (HDER), and lower dose edoxaban (LDER) regimens at extremes of BW in ENGAGE AF-TIMI 48.

METHODS AND RESULTS

 We analyzed three BW groups: low BW (LBW: <5th percentile, ≤55 kg, N = 1,082), middle BW (MBW: 45th-55th percentile, 79.8-84 kg, N = 2,153), and high BW (HBW: >95th percentile, ≥120 kg, N = 1,093). In the warfarin arm, LBW patients had higher rates of stroke/systemic embolism (SSE: 6.5 vs. 4.7 in MBW vs. 1.6% in HBW, P _trend < 0.001), major bleeding (MB: 9.3 vs. 7.7 vs. 6.5%, P _trend = 0.08), and worse net clinical outcome of systemic embolic event, MB, or death (31.5 vs. 19.1 vs. 16.0%, P _trend < 0.0001). The time-in-therapeutic range with warfarin was lowest in LBW patients (63.0 vs. 69.3 vs. 70.1% patients, P _trend < 0.001). The pharmacokinetic/pharmacodynamic profile of edoxaban was consistent across BW groups. The risk of SSE was similar between HDER and warfarin for each of the three weight groups (P _int = 0.52, P _int-trend = 0.86). MB was reduced by LDER versus warfarin (P _int = 0.061, P _int-trend = 0.023), especially in LBW patients. Net clinical outcomes were improved by HDER versus warfarin (P _int = 0.087, P _int-trend = 0.027), especially in LBW patients.

CONCLUSION

 Patients with LBW in ENGAGE AF-TIMI 48 had in general a more fragile clinical status and poorer international normalized ratio control. The pharmacokinetic/pharmacodynamic profile of edoxaban was consistent across extremes of BW, resulting in similar efficacy compared with warfarin, while major or clinically relevant non-MB and net outcomes were most favorable with edoxaban as compared to warfarin in LBW patients.

Towards Personalized Antithrombotic Treatments: Focus on P2Y12 Inhibitors and Direct Oral Anticoagulants

Oral anticoagulants and antiplatelet drugs are commonly prescribed to lower the risk of cardiovascular diseases, such as venous and arterial thrombosis, which represent the leading causes of mortality worldwide. A significant percentage of patients taking antithrombotics will nevertheless experience bleeding or recurrent ischemic events, and this represents a major public health issue. Cardiovascular medicine is now questioning the one-size-fits-all policy, and more personalized approaches are increasingly being considered. However, the available tools are currently limited and they are only moderately able to predict clinical events or have a significant impact on clinical outcomes. Predicting concentrations of antithrombotics in blood could be an effective means of personalization as they have been associated with bleeding and recurrent ischemia. Target concentration interventions could take advantage of physiologically based pharmacokinetic (PBPK) and population-based pharmacokinetic (POPPK) models, which are increasingly used in clinical settings and have attracted the interest of governmental regulatory agencies, to propose dosages adapted to specific population characteristics. These models have the benefit of combining parameters from different sources, such as experimental in vitro data and patients' demographic, genetic, and physiological in vivo data, to characterize the dose-concentration relationships of compounds of interest. As such, they can be used to predict individual drug exposure. In the near future, these models could therefore be a valuable means of predicting personalized antithrombotic blood concentrations and, hopefully, of preventing clinical non-response or bleeding in a given patient. Existing approaches for personalization of antithrombotic prescriptions will be reviewed using practical examples for P2Y₁₂ inhibitors and direct oral anticoagulants. The review will additionally focus on the existing PBPK and POPPK models for these two categories of drugs. Lastly, we address potential scenarios for their implementation in clinics, along with the main limitations and challenges.

[Direct oral anticoagulants: In which indications? Which one to prescribe? For or against their use in frail patients and in atypical cases? Which monitoring and management haemorrhage complications?]

Since their approval, the direct oral anticoagulants have been widely used in the management of venous thromboembolism, for stroke and systemic embolism prevention in non valvular atrial fibrillation, and in venous thromboembolism prophylaxis after surgical hip or knee replacement. Because they are easy to use, with oral fixed doses and no biological monitoring need, they are more and more prescribed. New indications are rising in cancer associated thrombosis in France beyond the 6 first months of treatment, and to prevent cardiovascular events after an acute coronary syndrome, or in stable coronary or peripheral arterial disease in Europe. The efficacity and safety of direct oral anticoagulants in frail patients or in unusual pathological contexts are not entirely known, but further data are coming and will probably bring new answers.

Novel assay based on diluted prothrombin time reflects anticoagulant effects of direct oral factor Xa inhibitors: Results of multicenter study in Japan

BACKGROUND

Direct oral anticoagulants targeting factor Xa (DXaIs) are administered as prophylaxis for various venothrombotic diseases without routine monitoring required. However, assessment of their anticoagulant effects is necessary to prevent severe events, including major bleeding and/or refractory thrombosis.

OBJECTIVES

We examined the correlation of ratio of inhibited thrombin generation (RITG), determined using a novel assay based on dilute prothrombin time (dPT), with coagulant markers and laboratory test results to show drug effects. In addition, RITG usefulness as a confirmation test for DXaI therapy was investigated.

METHODS

Citrated plasma samples were obtained from patients treated with rivaroxaban (n = 882), apixaban (n = 1214), or edoxaban (n = 820) at 4 different institutions in Japan. Laboratory tests, including prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer, and plasma concentrations of DXaIs, were conducted, with drug concentrations divided into peak and trough groups, within and after 5 h of administration.

RESULTS

In each DXaI group, RITG was positively correlated with PT, APTT, and drug concentration, and negatively with D-dimer. RITG fluctuation during the peak and trough periods reflected the anticoagulant activity characteristic of each DXaI, which was different from blood concentration fluctuations. RITG showed a significant decrease in cases with thrombosis, while that was increased in those with hemorrhage.

CONCLUSION

We developed RITG, a novel measurement method based on dPT. RITG represents residual coagulation ability in plasma samples, and is useful for assessment of bleeding and thrombotic tendencies in DXaI patients. RITG can be utilized to confirm the effectiveness of oral anticoagulation therapy with DXaI agents.

Thromboembolic and bleeding risk in obese patients with atrial fibrillation according to different anticoagulation strategies

BACKGROUND

Data on the relationship between body mass index (BMI), thromboembolic events (TEE) and bleeding in patients with atrial fibrillation (AF) are controversial, and further evidence on the risk of such events in obese patients with AF receiving different anticoagulant therapies (OAC) is needed.

METHODS AND RESULTS

We divided a total of 9330 participants from the prospective PREFER in AF and PREFER in AF PROLONGATION registries into BMI quartiles at baseline. Outcome measures were TEE and major bleeding complications at the 1-year follow-up. Without OAC, there was a ≥6-fold increase of TEE in the 4th vs other BMI quartiles (P = .019). OAC equalized the rates of TEE across different BMI strata. The occurrence of major bleeding was highest in patients with BMI in the 1st as well as in the 4th BMI quartile [OR 1.69, 95% CI 1.03-2.78, P = .039 and OR 1.86, 95% CI 1.13-3.04, P = .014 vs those in the 3rd quartile, respectively]. At propensity score-adjusted analysis, the incidence of TEE and major bleeding in obese patients receiving non-vitamin K antagonist oral anticoagulants (NOACs) or vitamin K-antagonist anticoagulants (VKAs) was similar (P ≥ .34).

CONCLUSIONS

Our real-world data suggest no obesity paradox for TEE in patients with AF. Obese patients are at higher risk of TEE, and here OAC dramatically reduces the risk of events. We here found a comparable clinical outcome with NOACs and VKAs in obese patients. Low body weight and obesity were also associated with bleeding, and therefore OAC with the best safety profile should be considered in this setting.

Obesity Paradox in Atrial Fibrillation: Implications for Outcomes and Relationship with Oral Anticoagulant Drugs

In the last 40 years, concern about the obesity epidemic has increased. Data from the current literature highlight a strong relationship between obesity and atrial fibrillation (AF), particularly in relation to an increased risk for incident and recurrent AF. A phenomenon called the "obesity paradox" has emerged: the apparently counterintuitive evidence from epidemiological data indicating that overweight and obese patients may have a better prognosis than healthy-weight patients. A differential impact of oral anticoagulants (OACs) in terms of effectiveness and safety in the various body mass index categories has been postulated, particularly in the comparison between non-vitamin-K antagonist oral anticoagulants and vitamin K antagonists. This review aims to summarize the evidence on the impact of obesity in patients with AF, focusing on descriptions of the obesity paradox and its relationships with OAC treatment.

Validation of the VTE-BLEED score's long-term performance for major bleeding in patients with venous thromboembolisms: From the COMMAND VTE registry

BACKGROUND

The recently proposed VTE-BLEED score to predict the risk of major bleeding in patients with venous thromboembolisms (VTEs) on prolonged anticoagulation therapy was validated externally in randomized controlled trials and in a selected cohort, but not applied in non-selective cohorts.

OBJECTIVES

The present study aimed to evaluate the generalizability of the VTE-BLEED score in a non-selective cohort.

PATIENTS/METHODS

The COMMAND VTE Registry is a multicenter retrospective registry enrolling consecutive patients with acute symptomatic VTEs among 29 centers in Japan. The present study population consisted of 2124 patients with prolonged anticoagulation therapy beyond 30 days, including 2008 (95%) patients with a first VTE episode and 1075 (51%) with unprovoked VTEs, who were divided into 1445 patients (68%) with a VTE-BLEED score of ≥2 (high-risk group) and 679 (32%) with a VTE-BLEED score of <2 (low-risk group).

RESULTS

During a median follow-up period of 672 days, major bleeding events occurred in 121 patients. The cumulative 5-year incidence of major bleeding beyond 30 days was significantly higher in the high-risk group than low-risk group (13.2% versus 5.4%, P < .001). The hazard function curves demonstrated that the hazards of the high-risk group were consistently higher over time compared with the low-risk group, which suggested the long-term predictive ability of the score.

CONCLUSIONS

In the present real-world VTE registry, the VTE-BLEED score had  a long-term predictive ability for high-risk patients with major bleeding during prolonged anticoagulation therapy, which could be useful in determining the optimal duration of anticoagulation therapy in individual patients.

Obesity and atrial fibrillation: making inroads through fat

The global prevalence of obesity has reached epidemic proportions, paralleled by a rise in cases of atrial fibrillation (AF). Data from epidemiological cohorts support the role of obesity as an independent risk factor for AF. Increasing evidence indicates that obesity may contribute to the AF substrate through a number of pathways including by altering epicardial adipose tissue biology, inflammatory pathways, structural cardiac remodelling, and inducing atrial fibrosis. Due to changes in pharmacokinetics and pharmacodynamics, specific therapeutic considerations are required to guide management of patients with AF including anticoagulation and rhythm control. Also, weight loss in patients with AF has been associated with reduced progression from paroxysmal to persistent AF and indeed regression from persistent to proximal AF. However, the role of dietary intervention in AF control remains to be fully elucidated and hard prospective outcome data to support weight loss are required in AF to determine its role as part of a comprehensive risk factor management strategy for AF in obese patients.

Direct Oral Anticoagulants in Patients With Nonvalvular Atrial Fibrillation and Low Body Weight

BACKGROUND

It is unclear whether the overall effectiveness and safety of direct oral anticoagulants (DOACs) are consistent in patients with nonvalvular atrial fibrillation (AF) and extremely low body weight (<50 kg).

OBJECTIVES

This study compared DOACs with warfarin in AF patients with low body weight.

METHODS

Using data from the Korean National Health Insurance Service database from January 2014 to December 2016, AF patients with body weight ≤60 kg and who were treated with oral anticoagulants (n = 14,013 taking DOACs and n = 7,576 taking warfarin) were included and examined for ischemic stroke, intracranial hemorrhage (ICH), gastrointestinal bleeding, major bleeding, all-cause death, and composite outcome. The propensity score weighting was used to balance the 2 groups.

RESULTS

Baseline characteristics were well balanced between the 2 groups (mean age 73 years, mean CHA₂DS₂-VASc score 4, and 28% of patients weighed <50 kg). DOACs were associated with lower risks of ischemic stroke (hazard ratio [HR]: 0.591; 95% confidence interval [CI]: 0.510 to 0.686) and major bleeding (HR: 0.705; 95%: CI 0.601 to 0.825), which were caused by a reduction in ICH (HR: 0.554; 95% CI: 0.429 to 0.713) compared with warfarin. DOAC improved the net clinical benefit compared with warfarin (HR for composite outcome: 0.660; 95% CI: 0.606 to 0.717), and this was consistent in patients who weighed <50 kg (HR for composite outcome: 0.665; 95% CI: 0.581 to 0.762).

CONCLUSIONS

In this real-world Asian AF population with low body weight, DOACs showed better effectiveness and safety than warfarin. These results were consistent in patients with extremely low body weight. Regular dosages of DOACs showed comparable results as reduced dosages of DOACs in both effectiveness and safety.

Optimal Rivaroxaban Dose in Asian Patients With Atrial Fibrillation and Normal or Mildly Impaired Renal Function

Background and Purpose- Although rivaroxaban 15 mg (R15) was only given to patients with creatinine clearance (CrCl) ≤50 mL/min in the pivotal clinical trial, this dose has been commonly prescribed in Asian patients with nonvalvular atrial fibrillation regardless of renal function. There is a paucity of information on the clinical outcomes of R15 compared with rivaroxaban 20 mg (R20) in patients with CrCl ≥50 mL/min. This study aimed to examine the effectiveness and safety of 2 doses of rivaroxaban in Asian patients with atrial fibrillation and CrCl ≥50 mL/min. Methods- Using the Korean National Health Insurance Service database, patients with atrial fibrillation and normal or mildly impaired renal function (CrCl ≥50 mL/min) and naive to rivaroxaban or warfarin were included from January 2014 to December 2016. Three separate 1:1 propensity score-matched cohorts were conducted: R20 versus warfarin (n=15 584), R15 versus warfarin (n=11 554), and R20 versus R15 (n=10 392). Hazard ratios for ischemic stroke, intracranial hemorrhage, gastrointestinal bleeding, major bleeding, all-cause death, and composite clinical outcome were analyzed. Results- Compared with warfarin, both R20 and R15 showed significantly lower risk for ischemic stroke, major bleeding (mainly through reduction of intracranial hemorrhage), and all-cause death. Compared with R15, R20 showed better results for the composite clinical outcome (hazard ratio, 0.852; 95% CI, 0.735-0.988). This benefit was consistently observed in patients aged ≥80 years and those <50 kg. R20 was associated with higher risk of major bleeding than R15 in patients with marginal CrCl (50-60 mL/min). Conclusions- Among Asians with atrial fibrillation and CrCl ≥50 mL/min, both R20 and R15 were associated with reduced risk of ischemic stroke, intracranial hemorrhage, major bleeding, and all-cause death without significantly increased risk of gastrointestinal bleeding compared with warfarin. In patients with CrCl ≥50 mL/min, on-label R20 showed better results for the composite clinical outcome compared with off-label R15.

The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

The current manuscript is the second update of the original Practical Guide, published in 2013 [Heidbuchel et al. European Heart Rhythm Association Practical Guide on the use of new oral anticoagulants in patients with non-valvular atrial fibrillation. Europace 2013;15:625-651; Heidbuchel et al. Updated European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist anticoagulants in patients with non-valvular atrial fibrillation. Europace 2015;17:1467-1507]. Non-vitamin K antagonist oral anticoagulants (NOACs) are an alternative for vitamin K antagonists (VKAs) to prevent stroke in patients with atrial fibrillation (AF) and have emerged as the preferred choice, particularly in patients newly started on anticoagulation. Both physicians and patients are becoming more accustomed to the use of these drugs in clinical practice. However, many unresolved questions on how to optimally use these agents in specific clinical situations remain. The European Heart Rhythm Association (EHRA) set out to coordinate a unified way of informing physicians on the use of the different NOACs. A writing group identified 20 topics of concrete clinical scenarios for which practical answers were formulated, based on available evidence. The 20 topics are as follows i.e., (1) Eligibility for NOACs; (2) Practical start-up and follow-up scheme for patients on NOACs; (3) Ensuring adherence to prescribed oral anticoagulant intake; (4) Switching between anticoagulant regimens; (5) Pharmacokinetics and drug-drug interactions of NOACs; (6) NOACs in patients with chronic kidney or advanced liver disease; (7) How to measure the anticoagulant effect of NOACs; (8) NOAC plasma level measurement: rare indications, precautions, and potential pitfalls; (9) How to deal with dosing errors; (10) What to do if there is a (suspected) overdose without bleeding, or a clotting test is indicating a potential risk of bleeding; (11) Management of bleeding under NOAC therapy; (12) Patients undergoing a planned invasive procedure, surgery or ablation; (13) Patients requiring an urgent surgical intervention; (14) Patients with AF and coronary artery disease; (15) Avoiding confusion with NOAC dosing across indications; (16) Cardioversion in a NOAC-treated patient; (17) AF patients presenting with acute stroke while on NOACs; (18) NOACs in special situations; (19) Anticoagulation in AF patients with a malignancy; and (20) Optimizing dose adjustments of VKA. Additional information and downloads of the text and anticoagulation cards in different languages can be found on an EHRA website (www.NOACforAF.eu).

Evaluation of the efficacy of direct oral anticoagulants (DOACs) in comparison to warfarin in morbidly obese patients

Purpose: There is limited clinical data evaluating anticoagulation with the direct oral anticoagulants (DOACs) in morbidly obese patients. We sought to examine the efficacy in preventing stroke or other systemic embolic events and safety of apixaban, dabigatran, and rivaroxaban, in comparison to warfarin in patients with either a body-mass index (BMI) over 40 kg/m2 and/or a weight over 120 kg.Methods: After approval from IRB, we collected retrospective data from our institution's records on 180 patients. We analyzed the rates of stroke and systemic embolic events as defined as ischemic stroke, pulmonary embolism (PE), deep vein thrombosis (DVT), and myocardial infarction (MI) as well as major bleeding in morbidly obese patients receiving apixaban, dabigatran, or rivaroxaban in comparison to warfarin for anticoagulation due to nonvalvular atrial fibrillation, postoperative thrombus prophylaxis, or DVT/PE treatment and/or reduction in risk for recurrence.Results: The final analysis included 90 patients in both arms. Fifty-two percent (n = 41) of patients in the DOAC group were on apixaban therapy, 12% (n = 11) on dabigatran, and 37% (n = 33) on rivaroxaban. The average BMI and weight in the DOAC group were 46.7 kg/m2 and 139.3 kg, respectively. In the warfarin group, average BMI and weight were 45.8 kg/m2 and 135.9 kg, respectively. There were 11 patients who developed a stroke or thromboembolic event in the DOAC group and 10 in the warfarin group (OR 1.11, 95% confidence interval [CI] 0.45-2.78; p = 0.82). The events in the DOAC group consisted of three patients who developed ischemic stroke, three patients who developed DVTs, one who developed a PE, and four patients who developed MIs. There were two major bleeding events in the DOAC group and three events in the warfarin group (p = 0.65).Conclusions: Anticoagulation therapy with DOACs in morbidly obese patients may be a safe and effective alternative to warfarin for prevention of stroke or systemic embolic events. However, additional studies are necessary to confirm these findings.

Patients with higher body mass index treated with direct / novel oral anticoagulants (DOAC / NOAC) for atrial fibrillation experience worse clinical outcomes

INTRODUCTION

Due to fixed dosing of direct oral anticoagulants (DOACs), uncertainty exists about their efficacy in a population of obese/overweight patients.

PATIENTS AND METHODS

We retrospectively investigated a real-life cohort of 325 DOAC anticoagulated patients with atrial fibrillation [179 receiving dabigatran (55%), 74 apixaban (23%) and 72 rivaroxaban (22%)]. Patients were stratified according to the body mass index (BMI) into non-obese (233 with BMI <30 kg/m²), class I obesity (71 with BMI 30-34.9 kg/m²) and class II + obesity (21 with BMI ≥35 kg/m²).

RESULTS

Patients with higher BMI receiving DOACs were more likely to experience stroke/systemic embolism sooner (P = 0.043), experience major bleeding sooner (P < 0.001) and have shorter time to composite event consisting of thrombosis, bleeding or death (P < 0.001) whereas there was no significant association with overall survival (P = 0.470). BMI was significantly associated with thrombosis but not bleeding among dabigatran treated patients, and significantly associated with bleeding but not thrombosis among patients treated with factor Xa inhibitors. Associations of higher thrombotic, bleeding and composite endpoint risks with higher BMI remained statistically significant in multivariate Cox regression models adjusted for age, gender, eGFR, CHA₂DS₂VASC and HAS-BLED.

CONCLUSION

Our findings indicate that obese patients receiving DOACs, especially ones with class II + obesity, might be under higher risks of stroke/bleeding depending on DOAC subtype. Loss of efficacy might be associated with dabigatran, whereas higher risk of major bleeding might be associated with factor Xa inhibitors.

Investigation of Direct-Acting Oral Anticoagulants and the Incidence of Venous Thromboembolism in Patients Weighing ≥120 kg Compared to Patients Weighing <120 kg

Background:

Direct oral anticoagulants (DOACs) present a favorable alternative to warfarin based on the decreased burden of monitoring and fewer drug and food interactions. Although studied in the general population, limited clinical data justifying efficacy in patients weighing ≥120 kg present concern for using DOACs in this specific population.

Objective:

The purpose was to identify if a difference exists in incidence of recurrent thromboembolic events in patients receiving a DOAC for the indication of venous thromboembolism (VTE) weighing ≥120 kg compared to patients weighing <120 kg.

Methods:

A retrospective database analysis was conducted with patients on apixaban, dabigatran, or rivaroxaban for treatment of VTE from the Veterans Integrated Service Network 8 between January 2012 and June 2017. The primary outcome was incidence of recurrent VTEs while on anticoagulation. Fisher’s exact tests were used to evaluate difference in VTEs between the groups.

Results:

There were 133 patients weighing ≥120 kg and 1063 patients weighing <120 kg identified within the 5-year time frame that met inclusion criteria. Although no statistically significant difference was found in incidence of recurrent VTEs between study groups (0.8% vs 1.1%; odds ratio: 0.66; 95% confidence interval: 0.09-5.14; P = .69) few events occurred limiting the power to be able to detect a difference.

Conclusion:

This study found no difference in VTE recurrence in patients weighing ≥120 kg compared to patients <120 kg with few events in either group. Although promising, additional studies are needed to confirm these findings.

Morbidly Obese Patient on Rivaroxaban Presents With Recurrent Upper Extremity Deep Vein Thrombosis: A Case Report

A morbidly obese patient with history of deep vein thrombosis and pulmonary embolism was diagnosed with an acute left upper extremity deep vein thrombosis and started on rivaroxaban. Three months later, the patient returned with swelling in the right arm and was found to have a right brachial thrombosis. Anticoagulant therapy was switched to a low-molecular-weight heparin, and patient was discharged on enoxaparin along with an order to follow-up with a hematologist. Subanalyses from randomized controlled trials, pharmacokinetic/pharmacodynamic, and real-world studies suggest that rivaroxaban may be effective and safe in morbidly obese patients for primary and secondary prevention of venous thromboembolism. However, the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis does not recommend the use of direct-acting oral anticoagulants in this population. If used, drug levels should be monitored to guide the therapy. Due to the disparity in data to show efficacy and safety of rivaroxaban in morbidly obese subjects, the interpatient variability of rivaroxaban’s effects in subjects, and the lack of defined therapeutic range for rivaroxaban drug concentration, rivaroxaban should be used cautiously in this population.

Safety and Effectiveness of Edoxaban in Japanese Patients With Venous Thromboembolism - An Interim Analysis of Data From a Japanese Postmarketing Observational Study (ETNA-VTE-Japan)

BACKGROUND

ETNA-VTE-Japan is an ongoing prospective observational study conducted as part of a postmarketing observational study to investigate the safety and effectiveness of edoxaban in Japanese patients for whom the drug has been newly prescribed to treat venous thromboembolism (VTE) and prevent VTE recurrence. The results of an interim analysis of data collected at 3 months are presented.Methods and Results:A total of 1,732 patients were enrolled. The safety and effectiveness analyses included data from 1,703 and 1,699 patients, respectively. In the safety analysis set, 39.4% of patients were aged ≥75 years, 58.2% had body weight ≤60 kg, and 22.2% had creatinine clearance <50 mL/min. Approximately 90% of patients received a dose in accordance with the package insert. Approximately 80% of patients continued treatment; the mean treatment period was 74.5 days. The incidence of bleeding adverse events and major bleeding was 6.3% and 1.4%, respectively. The incidence of VTE recurrence and symptomatic VTE recurrence in the on-treatment population was 0.8% and 0.4%, respectively. Safety and effectiveness profiles of edoxaban in patients receiving the low dose (30 mg/day), generally administered to patients with high bleeding risk, were similar to those of the standard dose (60 mg/day).

CONCLUSIONS

The results confirm no major concerns about the safety and effectiveness of edoxaban in Japanese patients with VTE in the first 3 months of treatment. (Trial registration No.: UMIN000016387.).

Impact of Body Mass Index on Outcomes in the Edoxaban Versus Warfarin Therapy Groups in Patients Underwent Cardioversion of Atrial Fibrillation (from ENSURE-AF)

In the EdoxabaN versus warfarin in subjectS UndeRgoing cardiovErsion of Atrial Fibrillation study (NCT 02072434), edoxaban showed similar efficacy and safety versus enoxaparin-warfarin in patients underwent electrical cardioversion of nonvalvular atrial fibrillation. In this ancillary analysis, we compared the primary efficacy (composite of stroke, systemic embolic event, myocardial infarction, cardiovascular death, and overall study period) and safety (composite of major and clinically relevant nonmajor bleeding, on-treatment) end points in relation to body mass index (BMI; <30 vs ≥30 kg/m²). We also compared cardioversion outcomes in relation to BMI. Of 2,199 patients enrolled, 1,095 were randomized to edoxaban and 1,104 to enoxaparin-warfarin. Mean age was 64 ± 10 and 64 ± 11 years and mean BMI 30.6 and 30.7 kg/m², respectively. Cardiovascular and metabolic diseases were more prevalent in obese (n = 1067) than nonobese patients. Overall ischemic event rates were low; rates in the BMI <30 kg/m² subgroup were numerically lower than the ≥30 kg/m² subgroup, but not significantly different (odds ratio [OR], 0.74 [95% confidence interval 0.23, 2.24]). Composite major + clinically relevant nonmajor bleeding rates were low and numerically lower, but not significantly different (OR 0.88 [0.38, 2.04]), between the edoxaban and enoxaparin-warfarin arms and across weight categories. Successful cardioversion rate was higher in the BMI <30 versus ≥30 kg/m² subgroup (73.9% vs 69.9%; OR 1.22 [1.01 to 1.48]). In EdoxabaN versus warfarin in subjectS UndeRgoing cardiovErsion of Atrial Fibrillation, BMI did not significantly impact the relative efficacy and safety of edoxaban versus enoxaparin-warfarin. Nevertheless, the nonobese group had a higher rate of cardioversion success than the obese group.

Clinical pharmacist led hospital-wide direct oral anticoagulant stewardship program

Introduction

In the past decade, direct-acting oral anticoagulants (DOAC) have been introduced to medical practice for several indications, with a wide range of dosing regimens. As both over- and under-dosing might lead to life-threatening events, development of methods promoting safe and effective utilization of these agents is imperative. The Hadassah Clinical Pharmacy team initiated a hospital-wide program, for monitoring and promoting safe and effective prescription of DOAC during hospitalization. This study describes the types of drug related problems addressed and the program’s performance in terms of consultation rates and physician acceptance.

Methods

Electronic medical records throughout the hospital were screened for DOAC orders. All DOAC orders were assessed by a clinical pharmacist for potentially-inappropriate prescribing. When potentially-inappropriate prescribing or a drug-related problem was identified, the clinical pharmacist provided consultation on management options. In specific cases, additional guidance was provided by coagulation and pharmacology specialists. Data on patient characteristics, clinical pharmacist consultations, and physician response was retrospectively retrieved for the first six months of 2017. Characteristics of patients with and without consultations were compared, consultations were categorized by the recommended management of the drug related problem, and physician acceptance rates were evaluated by category.

Results

During the evaluated period, 585 patients with DOAC orders were identified. Patients were evenly distributed by gender, and age averaged 78 years. Most patients received apixaban (75%) followed by rivaroxaban (14%) and dabigatran (11%), and most (63%) received “reduced dose” regimens. Clinical pharmacists provided 258 consultations for 210 patients, regarding anticoagulation management, such that more than one in three patients on DOAC had potentially inappropriate prescribing or drug related problems. Consultations included alerts regarding potentially inappropriate DOAC doses and recommendations to increase (29%) or decrease (5%) the dose, potentially inappropriate concomitant antiplatelet agents (20%), need for DOAC level monitoring (23%), and alerts regarding other drug related problems (23%). More than 70% of recommendations were accepted by the attending physician.

Conclusion

Due to the complexity of DOAC management, potentially-inappropriate prescribing and drug related problems are common. Multidisciplinary collaborative projects including review and consultation by clinical pharmacists are an effective method of improving management of patients on DOAC.

Trial registration

Retrospectively registered at clinicaltrials.gov, NCT03527615.

LMU Munich: platelet inhibition novel aspects on platelet inhibition and function

A core research area in the Department of Cardiology at Ludwig-Maximilians-University (LMU) Munich focuses on antiplatelet therapy, its translational aspects, and its underlying mechanism with respect to platelet physiology. We are conducting a broad range of investigator-initiated clinical trials (phase II-IV) and preclinical studies on the topic of antithrombotic therapy for percutaneous coronary intervention patients, platelet activation, and reactivity as well as on novel inhibitors of platelet adhesion. Just recently, we completed the large multi-centre investigator-initiated TROPICAL-ACS trial on guided early de-escalation of antiplatelet treatment in acute coronary syndrome (ACS) patients (Sibbing et al. in Lancet 390:1747-1757, 2017; Sibbing et al. in Thromb Haemost 117:1240-1248), done at 33 sites in Europe. Furthermore, besides other ongoing clinical studies, we initiated and are currently recruiting patients for the multi-centre randomized APixaban versus PhenpRocoumon in Patients With ACS and AF: APPROACH-ACS-AF study as well as for the multi-centre phase II randomized, double-blind, placebo-controlled study of revacept in Patients With Stable Coronary Artery Disease (Revacept/CAD/02) trial.

THROMBOSIS OF LEFT ATRIAL APPENDAGE DURING THERAPY WITH DIRECT ORAL ANTICOAGULANT. CLINICAL CASE

The article presents a clinical observation of the left atrial appendage thrombosis in a 51-year-old female patient with a paroxysmal form of nonvalvular atrial fibrillation which occurred despite long-term anticoagulant therapy with apixaban in a full dose (5 mg b.i.d.), and the patient’s management. The patient was admitted with recurrent symptomatic paroxysm for more than 48 hours, because of which, in accordance with the recommendations, transesophageal echocardiography was performed before an emergency rhythm restoration. Thrombus in the left atrial appendage 0.5×1.03 cm in size was detected. It was decided to refrain from the immediate restoration of the rhythm due to the very high risk of thromboembolic complications. In connection with the categorical refusal of the patient from warfarin, it was decided to replace apixaban with another direct oral anticoagulant – dabigatran 150 mg bid for a period of 4 weeks followed by performing a control transesophageal echocardiographic study. As a result, no thrombus was found on control echocardiography. The particularity of this observation is concomitant hypertrophic cardiomyopathy and diabetes mellitus type 1 in this patient.

Antithrombotic therapy in patients with non-valvular atrial fibrillation undergoing percutaneous coronary intervention: should we change our practice after the PIONEER AF-PCI and RE-DUAL PCI trials?

The number of patients with atrial fibrillation undergoing percutaneous coronary intervention (PCI) is increasing. Since these patients have a CHA₂DS₂-VASc score of 1 or higher, they should be treated with oral anticoagulation to prevent stroke. However, combination therapy with oral anticoagulation for prevention of embolic stroke and dual platelet inhibition for prevention of coronary thrombosis significantly increases bleeding complications. The optimal combination, intensity and duration of antithrombotic combination therapy is still not known. In the rather small randomized WOEST trial, the combination of a vitamin K antagonist (VKA) and clopidogrel decreased bleeding compared to the conventional triple therapy with VKA, clopidogrel and aspirin. In the PIONEER AF-PCI trial, two rivaroxaban-based treatment regimens significantly reduced bleeding complications compared to conventional triple therapy without increasing embolic or ischemic complications following PCI. Dual therapy with rivaroxaban and clopidogrel appeared to provide an optimal risk-benefit ratio. In the RE-DUAL PCI trial, dual therapy with dabigatran also reduced bleeding complications compared to conventional triple therapy. With respect to the composite efficacy end point of thromboembolic events (myocardial infarction, stroke, or systemic embolism), death, or unplanned revascularization dabigatran-based dual therapy was non-inferior to VKA-based triple therapy. The upcoming trials AUGUSTUS with apixaban and ENTRUST-PCI with edoxaban will further examine the use of NOACs in this setting. While recent guidelines recommend NOAC-based dual therapy in only a subset of patients (those who are at increased risk of bleeding), the available data now suggest that this should be the preferred choice for the majority of patients. Adding aspirin to this primary choice for up to 4 weeks in patients at especially high ischemic risk would likely prevent atherothrombotic events, but this needs further investigation. Taken together, it is time to adjust our practice and move to dual therapy consisting of a NOAC plus clopidogrel in most patients.

Decision Algorithms for Direct Oral Anticoagulant Use in Patients With Nonvalvular Atrial Fibrillation: A Practical Guide for Neurologists

Direct oral anticoagulants (DOACs) are valid alternative options to vitamin K antagonists due to their limited interactions with drugs or food and the fact that they do not require regular coagulation monitoring. To this regard, recent practice guidelines recommend that DOACs should be considered as first-line anticoagulant therapy for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). This review (1) outlines current international guidelines for the management of DOACs to prevent stroke in patients with NVAF, (2) outlines indications for elderly patients as well as specific settings including acute coronary syndromes and intracranial hemorrhage, and (3) offers a practical guide for the use of DOACs in neurological settings.