DOACs - advances and limitations in real world

Future of factor XI inhibitors in cardiovascular practice

Anticoagulation is indicated for treatment and prevention of arterial and venous thrombosis. Targeting different steps of the coagulation process, currently available anticoagulants entail an increased risk of bleeding, which detrimentally impacts on prognosis and hinders the administration of an effective antithrombotic regimen. Factor XI (FXI) inhibition has emerged as a strategy to uncouple prevention of thrombosis from bleeding. Indeed, while FXI is crucial for the amplification phase in pathological thrombosis, it is ancillary in physiological hemostasis. A comprehensive search in several scientific databases has been performed to identify relevant studies in the field. In addition, ongoing trials have been searched for in proper datasets to provide an updated and comprehensive assessment of the current state of investigations on FXI inhibition. Many compounds have been tested to inhibit FXI at different stages (i.e., synthesis, activation, or interactions with target molecules and coagulation factors). These include antisense oligonucleotides, monoclonal antibodies, small molecules, natural peptides and aptamers. In phase 2 studies, FXI inhibitors reduced thrombotic complications without any corresponding increase in bleeding. FXI inhibitors were noninferior and potentially superior to low-molecular-weight heparin in orthopedic surgery and reduced bleeding compared to apixaban in patients with atrial fibrillation. FXI inhibition is also under testing in other conditions, including end-stage renal disease, cancer, or noncardioembolic stroke. FXI inhibition represents a promising and rapidly emerging approach for a number of clinical indications. This article reviews the rationale, evidence, pharmacology, and future applications of FXI inhibition.

Rapid Determination of Xa Inhibitor Activity in Blood Using a Microfluidic Device that Measures Platelet Deposition and Fibrin Generation Under Flow

Background

Patients taking direct oral anticoagulants (DOACs) often present complicated scenarios following major bleeding, stroke, or emergency surgery. Rapid whole blood assays of DOAC levels would aid clinical decisions such as the need for DOAC reversal.

Methods

We developed a single-use, storage-stable, eight-channel microfluidic device to estimate factor Xa (FXa) inhibitor (apixaban or rivaroxaban) levels in venous thromboembolism or atrial fibrillation patients. The assay simultaneously measured whole blood clotting dynamics on collagen/tissue factor (TF; wall shear rate, 200 -1 ) under four ex vivo conditions: no-treatment control, high dose Factor Xa inhibition, low dose or high dose FXa reversal agent (andexanet alfa). Fibrin and platelet deposition dynamics were monitored via two-color epifluorescence microscopy. Plasma samples were also evaluated by LC-MS/MS for DOAC concentrations.

Results

Experiments with healthy volunteer blood spiked with DOAC verified device performance (DOAC IC 50 ∼120 nM) and confirmed that andexanet alfa added to healthy donor blood had no off-target effect on platelet or fibrin signal. Patient whole blood monitored for 15 to 25 minutes (17 minutes mean runtime) allowed calculation of functional DOAC concentrations ranging from 2 to 500 nM that correlated well with LC-MS/MS determination of apixaban or rivaroxaban (R 2  = 0.7 or 0.9, respectively). Platelet dysfunction was not observed in any patient on DOAC. For a threshold of 100 nM DOAC, the area under the curve (AUC) was found to be 0.881 for apixaban and 0.933 for rivaroxaban.

Conclusion

Microfluidic testing of whole blood can provide a rapid estimate of DOAC levels over the on-therapy range.

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

BACKGROUND

Data on availability, affordability, and accessibility is key for the planning of global strategies to reduce the burden of venous thromboembolism (VTE).

OBJECTIVES

A survey was conducted for the 10th anniversary of World Thrombosis Day to assess the availability of VTE therapies worldwide and challenges in uniform implementation.

METHODS

We gathered information on the approval status, availability, utilization, occurrence of shortages, and spread of medical and interventional therapies for VTE. Furthermore, we collected information by accessing or contacting national or continental medicines agencies, manufacturers or distributors, and online drug repositories.

RESULTS

We obtained data from a total of 69 countries: 33 countries in Europe, 19 in Asia, 7 in the Americas, 9 in Africa, and 1 in Oceania. Unfractionated heparin, low-molecular-weight heparin, and vitamin K antagonists were available in almost all countries, but shortages were recorded in 13%, 19%, and 15% of them, respectively. Direct oral anticoagulants were available in approximately three-quarters of the surveyed countries. At least one parenteral medication for heparin-induced thrombocytopenia was available in 57% of countries and a shortage was reported in 9% of these. Shortage of thrombolytics was recorded in 50% of countries. Overall, at least one type of catheter-directed therapy system was approved for use in 77% of countries and available in 23% of surveyed institutions. Our findings revealed notable geographic disparities in the worldwide availability of VTE therapies, the access to which appeared to be limited by economic and geopolitical factors.

CONCLUSION

We anticipate that this comprehensive information will play a pivotal role in highlighting the shortcomings of VTE therapies and the lack of homogeneous availability globally.

Direct oral anticoagulant (DOAC) monitoring within primary care: a quality improvement project

BACKGROUND

Poor monitoring of anticoagulants is a significant area of patient safety. It can lead to the dichotomous risk of haemorrhage/clotting without appropriate counselling and monitoring. While healthcare professionals may be familiar with the anticoagulant warfarin and the international normalised ratio, they might be unaware of the monitoring requirements of direct oral anticoagulants (DOACs), despite DOACs making up 62% of anticoagulants prescribed. The goal of this quality improvement (QI) project was to increase the compliance of monitoring of DOACs within general practice (GP) to improve patient safety and reduce the risk of an adverse outcome for patients.

LOCAL PROBLEM

In 2019, the GP surgery had 318 patients prescribed a DOAC and their medication reviews took place opportunistically. While initially, monitoring levels were nearly 100%, by December 2018 this had dropped significantly, and clinicians stated they were unfamiliar with this medication.

METHODS AND INTERVENTIONS

This project aimed to resolve this by using QI methodology and Plan-Do-Study-Act (PSDA) cycles to create new sustainable processes with DOAC monitoring and aimed to increase DOAC monitoring by 20% within 6 months.

RESULTS

Within 6 months, the project improved the rate of monitoring, and 49% of all patients prescribed a DOAC were seen in a DOAC clinic (n=156) and 78% (n=230/294) had DOAC counselling; 97% (n=295/304) had appropriate blood tests and 72% (n=216/298) had a recent weight recorded within their medical records. Three years on, 600 patients within the practice are prescribed DOACs and 74% (n=445) have had an annual review adhering to the gold standards set within the project.

CONCLUSION

This QI project confirms that monitoring of DOACs can be improved within primary care by using QI methodology and improving patient safety, using PDSA cycles, stakeholder engagement and the introduction of the anticoagulant domains within the nationwide Quality Assurance and Improvement Framework.

Direct-Acting Oral Anticoagulant Therapy in Cancer Patients-A Review

Venous thromboembolism (VTE) is an important aspect in cancer patients. There are various pharmacological methods used for thrombotic event treatment. DOACs (direct-acting oral anticoagulants) are gaining popularity among both physicians and researchers and are slowly starting to replace VKAs (vitamin K antagonists), thus becoming a substitute or alternative option for LMWHs (low-molecular-weight heparins). In this article, we present DOACs' main therapeutic advantages and disadvantages in patients with cancer. The only major concern with using DOACs is the higher risk of bleeding; however, there are discrepancies in this matter. There are still some types of cancer for which DOACs are not recommended. Specific cancer types may influence the efficacy of DOAC therapy. Additionally, race and ethnicity may affect therapy in cancer patients with DOACs. A sizeable number of clinical trials are focused on comparing DOACs with other anticoagulants. The current guidelines of different scientific associations are not unanimous in their DOAC assessments. There is still a need for more evidence of DOACs' potential advantages over other methods of anticoagulation in cancer patients to facilitate their position in this recommendation. This literature review presents the current state of knowledge about the use of DOACs in patients with neoplastic growth.

The anticoagulation length of therapy and risk of new adverse events in venous thromboembolism (ALTERNATIVE) study: Design and survey results

The Anticoagulation Length of Therapy and Risk of New Adverse Events In Venous Thromboembolism (ALTERNATIVE) study was designed to compare the benefits and harms of different treatment options for extended treatment of venous thromboembolism (VTE). In this paper, we describe the study cohort, survey data collection, and preliminary results. We identified 39,605 adult patients (age ≥ 18 years) from two large integrated health care delivery systems who were diagnosed with incident VTE and received initial anticoagulation therapy of 3 months or longer. A subset of the cohort (12,737) was invited to participate in a survey. Surveys were completed in English, Spanish or Mandarin via a mailed questionnaire, an online secure web link, or telephone. The survey domains included demographics, personal medical history, anticoagulant treatment history, anticoagulant treatment satisfaction, health-related quality of life and health literacy. A total of 5,017 patients participated in the survey for an overall response rate of 39.4%. The mean (SD) age of the survey respondents was 63.0 (14.5) years and self-reported race was 76.0% White/European, 11.1% Black/African American, and 3.8% Asian/Pacific Islander and 14.0% reported Hispanic ethnicity. Sixty percent of respondents completed the web survey, while 29.0% completed the mail-in paper survey, and 11.0% completed the survey via telephone. The ALTERNATIVE Study will address knowledge gaps by comparing several treatment alternatives for the extended management of VTE so that this information could be used by patients and clinicians to make more informed, patient-centered treatment choices.

Genetic variations in relation to bleeding and pharmacodynamics of dabigatran in Chinese patients with nonvalvular atrial fibrillation: A nationwide multicentre prospective cohort study

INTRODUCTION

To identify the potential factors responsible for the individual variability of dabigatran, we investigated the genetic variations associated with clinical outcomes and pharmacodynamics (PD) in Chinese patients with nonvalvular atrial fibrillation (NVAF).

MATERIALS AND METHODS

Chinese patients with NVAF taking dabigatran etexilate with therapeutic doses were enrolled. The primary (bleeding events) and secondary (thromboembolic and major adverse cardiac events) outcomes for a 2-year follow-up were evaluated. Peak and trough PD parameters (anti-FIIa activity, activated partial thromboplastin time and prothrombin time) were detected. Whole-exome sequencing, genome-wide sequencing and candidate gene association analyses were performed.

RESULTS

There were 170 patients with NVAF treated with dabigatran (110 mg twice daily) who were finally included. Two single-nucleotide polymorphisms (SNPs) were significantly related with bleeding, which include UBASH3B rs2276408 (odds ratio [OR] = 8.79, 95% confidence interval [CI]: 2.99-25.83, p = 7.77 × 10-5 at sixth month visit) and FBN2 rs3805625 (OR = 8.29, 95% CI: 2.87-23.89, p = 9.08 × 10-5 at 12th month visit), as well as with increased trends at other visits (p < .05). Furthermore, minor allele carriers of 16 new SNPs increased PD levels, and those of one new SNP decreased PD values (p < 1.0 × 10-5 ). Lastly, 33 new SNPs were found to be associated with bleeding and PD among 14 candidate genes. Unfortunately, the low number of secondary outcomes precluded further association analyses.

CONCLUSIONS

Genetic variations indeed affected bleeding and PD in Chinese patients with NVAF treated with dabigatran. The functions of these suggestive genes and SNPs might further be explored and verified in more in vivo and in vitro investigations.

Submassive Pulmonary Embolism in the Setting of Intracerebral Hemorrhage: A Case of Suction Thrombectomy

Pulmonary embolism (PE) in the setting of intracerebral hemorrhage (ICH) is an unfortunate, challenging, and highly morbid clinical problem. Interventional strategies have lower associated bleeding risks than the standby for PE treatment: systemic anticoagulation. Despite this benefit, there are few examples in the literature of its utilization in the management of PE in the setting of ICH. This present case provides an example of the successful utilization of suction thrombectomy to manage PE in the setting of ICH. An 80-year-old female presented to an outside hospital with complaints of dizziness, headache, nausea, and vomiting of abrupt onset one hour before arrival. Computed tomography (CT) of the head with CT Angiography (CTA) of the head and neck was performed and demonstrated hemorrhage in all ventricles; most prominently within the left lateral ventricle. Magnetic Resonance Imaging (MRI) of the brain suggested that the cause of her hemorrhage was reperfusion injury after a small acute infarction in the left internal capsule in the setting of anticoagulant use. Ten days after her diagnosis of ICH, a submassive PE was diagnosed with a class IV pulmonary embolism severity index (PESI). An interdisciplinary evaluation was conducted between hospitalist medicine, neurology, neurosurgery, and interventional radiology. A successful suction thrombectomy was performed on hospital day 11. No new neurologic deficits were appreciated post-procedure. The patient's heart rate remained elevated but improved. Blood pressure remained controlled. The patient was weaned off oxygen to room air. Neurosurgery assessed the patient to be of acceptable risk for discharge with the further deferment of anticoagulation until repeat CT head six weeks after discharge. The patient was discharged on hospital day 14. Treating PE in the setting of ICH is without clear guidelines. The appropriate treatment modality is reliant upon the clinical judgment and the individual details of each case. In this case, a high PESI with imaging demonstrating a stable hematoma without evidence of new blood resulted in the decision to use a suction thrombectomy. More research is needed to develop consistent evidence-based guidelines for this clinical challenge.

Population pharmacokinetic analysis for dabigatran etexilate in Chinese patients with non-valvular atrial fibrillation

We aimed to develop a pharmacokinetic (PK) and pharmacodynamic (PD) model from healthy Chinese subjects and real-world non-valvular atrial fibrillation (NVAF) patients. We also investigated meaningful intrinsic and extrinsic factors and related biomarkers for bleeding events. We characterized the integrated PK/PD models based on rich PK/PD data [dabigatran concentration, activated partial thromboplastin time (APTT), prothrombin time (PT), and anti-factor IIa (anti-FIIa) activity] from 118 healthy volunteers and sparse PD data [APTT, PT, and anti-FIIa] from 167 patients with NVAF after verifying the model extrapolation performance. We also documented the correlations between PD biomarkers and clinically relevant bleeding events over one year. Next, we used the final integrated PK/PD model (a two-compartment, linear model with first-order absorption) to evaluate the influence of dosage and individual covariates on PD parameters. The age, high-density liptein cholesterol (HDL-C), and creatinine clearance (CrCL) improved the PK model fit. The linear direct-effects PD model described the correlation between APTT, PT, and anti-FIIa and plasma concentration. CrCL improved the PD model fit. Anti-FIIa was more sensitive to the increase in dabigatran exposure than APTT and PT in the PD model. Therefore, fixed dabigatran doses could be prescribed for patients with NVAF without adjusting for age and HDL-C. We observed an elevated bleeding tendency with higher peak and trough values of APTT, PT, and anti-FIIa. Randomized studies should be performed to evaluate the efficacy and safety of low-dose dabigatran in Chinese patients with NVAF.

Marine Biological Macromolecules and Chemically Modified Macromolecules; Potential Anticoagulants

Coagulation is a potential defense mechanism that involves activating a series of zymogens to convert soluble fibrinogen to insoluble fibrin clots to prevent bleeding and hemorrhagic complications. To prevent the extra formation and diffusion of clots, the counterbalance inhibitory mechanism is activated at levels of the coagulation pathway. Contrariwise, this system can evade normal control due to either inherited or acquired defects or aging which leads to unusual clots formation. The abnormal formations and deposition of excess fibrin trigger serious arterial and cardiovascular diseases. Although heparin and heparin-based anticoagulants are a widely prescribed class of anticoagulants, the clinical use of heparin has limitations due to the unpredictable anticoagulation, risk of bleeding, and other complications. Hence, significant interest has been established over the years to investigate alternative therapeutic anticoagulants from natural sources, especially from marine sources with good safety and potency due to their unique chemical structure and biological activity. This review summarizes the coagulation cascade and potential macromolecular anticoagulants derived from marine flora and fauna.

Non-vitamin K antagonist oral anticoagulants in venous thromboembolism patients: a meta-analysis of real-world studies

BACKGROUND

The real-world studies on recurrent venous thromboembolism (VTE) and bleeding events of non-vitamin K antagonist oral anticoagulants (NOACs) in VTE patients have reported conflicting findings. Our study aimed to provide the direct comparison evidence of different NOACs for VTE patients in clinical practice settings.

METHODS

Search of the medical literature was conducted using PubMed, Web of Science, EMBASE, Clinical Trials.gov, and the Cochrane Library from inception to March 22, 2021. Among the 19,996 citations retrieved, a total of 63,144 patients from 6 studies were analyzed. Clinical outcomes included recurrent VTE, death, and different bleeding events.

RESULTS

Adjusted hazard ratio (HR) analysis suggested that apixaban had significant lower bleeding riskthan rivaroxaban (major, minor and any bleeding: HR = 0.61, 0.56, 0.70; p = 0.008, < 0.0001, 0.006, respectively), but no statistics difference found in recurrent VTE events (HR = 1.02, 95% confidence interval (CI) 0.71-1.47, p = 0.93). There was no significant difference of major bleeding between dabigatran and rivaroxaban (odds ratios (OR) = 0.41, 95% CI 0.09-1.90, p = 0.25), apixaban and dabigatran (OR 0.64, 95% CI 0.15-2.72, p = 0.83). No significant difference was found in the comparison of edoxaban and other NOACs in VTE recurrence, major bleeding and composite outcome.

CONCLUSIONS

In the prevention of bleeding events, apixaban was associated with a lower risk than rivaroxaban, but equivalent efficacy for different NOACs in prevention of recurrent VTE. Evidence generated from the meta-analysis based on real-world data can help to guide selection between apixaban and rivaroxaban in routine clinical practice.

TRIAL REGISTRATION

This systematic review and meta-analysis were conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis and Meta-analysis of Observational Studies in Epidemiology statements and was registered with PROSPERO (CRD42019140553).

Drive-Through Anticoagulation Clinic During the COVID-19 Pandemic

An innovative approach to anticoagulation management during the COVID-19 pandemic was used at our center that allowed patients to stay in their vehicle while our anticoagulation advanced practice registered nurse obtained blood for point-of-care international normalized ratio (INR) testing while education and counseling were completed. A significant improvement in the median percentage of INR within the therapeutic range was observed among the patients who used the drive-through clinic. A small group of patients improved compliance to anticoagulation monitoring. Clinical care models, such as this clinic approach may improve patient compliance and adherence to anticoagulation beyond the pandemic needs.

US Emergency Department Visits Attributed to Medication Harms, 2017-2019

IMPORTANCE

Assessing the scope of acute medication harms to patients should include both therapeutic and nontherapeutic medication use.

OBJECTIVE

To describe the characteristics of emergency department (ED) visits for acute harms from both therapeutic and nontherapeutic medication use in the US.

DESIGN, SETTING, AND PARTICIPANTS

Active, nationally representative, public health surveillance based on patient visits to 60 EDs in the US participating in the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance Project from 2017 through 2019.

EXPOSURES

Medications implicated in ED visits, with visits attributed to medication harms (adverse events) based on the clinicians' diagnoses and supporting data documented in the medical record.

MAIN OUTCOMES AND MEASURES

Nationally weighted estimates of ED visits and subsequent hospitalizations for medication harms.

RESULTS

Based on 96 925 cases (mean patient age, 49 years; 55% female), there were an estimated 6.1 (95% CI, 4.8-7.5) ED visits for medication harms per 1000 population annually and 38.6% (95% CI, 35.2%-41.9%) resulted in hospitalization. Population rates of ED visits for medication harms were higher for patients aged 65 years or older than for those younger than 65 years (12.1 vs 5.0 [95% CI, 7.4-16.8 vs 4.1-5.8] per 1000 population). Overall, an estimated 69.1% (95% CI, 63.6%-74.7%) of ED visits for medication harms involved therapeutic medication use, but among patients younger than 45 years, an estimated 52.5% (95% CI, 48.1%-56.8%) of visits for medication harms involved nontherapeutic use. The proportions of ED visits for medication harms involving therapeutic use were lowest for barbiturates (6.3%), benzodiazepines (11.1%), nonopioid analgesics (15.7%), and antihistamines (21.8%). By age group, the most frequent medication types and intents of use associated with ED visits for medication harms were therapeutic use of anticoagulants (4.5 [95% CI, 2.3-6.7] per 1000 population) and diabetes agents (1.8 [95% CI, 1.3-2.3] per 1000 population) for patients aged 65 years and older; therapeutic use of diabetes agents (0.8 [95% CI, 0.5-1.0] per 1000 population) for patients aged 45 to 64 years; nontherapeutic use of benzodiazepines (1.0 [95% CI, 0.7-1.3] per 1000 population) for patients aged 25 to 44 years; and unsupervised medication exposures (2.2 [95% CI, 1.8-2.7] per 1000 population) and therapeutic use of antibiotics (1.4 [95% CI, 1.0-1.8] per 1000 population) for children younger than 5 years.

CONCLUSIONS AND RELEVANCE

According to data from 60 nationally representative US emergency departments, visits attributed to medication harms in 2017-2019 were frequent, with variation in products and intent of use by age.

Thrombophilia testing in the era of direct oral anticoagulants

Venous thromboembolism (VTE) is increasingly recognised in primary and secondary care practice. The arrival of direct oral anticoagulants (DOACs) has made the management of VTE easier and more convenient. Some patients established on DOACs may need screening for underlying thrombophilias as certain thrombophilic conditions are known to confer a higher thrombosis risk, although the guidelines for when and how to test for a thrombophilia, especially in a patient taking a DOAC, are unclear. This literature review aims to examine when thrombophilia screening should take place in a patient already taking a DOAC, the effect of DOACs on thrombophilia tests, and analyse whether DOACs are safe and effective in both inherited and acquired thrombophilias.

Prevalence and the factors associated with oral anticoagulant use among nursing home residents

WHAT IS KNOWN AND OBJECTIVE

Anticoagulants are indicated for treatment and prevention of several clinical conditions. Prior studies have examined anticoagulant utilization for specific indications and in community-dwelling populations. Decision-making regarding anticoagulant prescribing in the nursing home setting is particularly challenging because advanced age and clinical complexity places most residents at increased risk for adverse drug events. To estimate the prevalence of oral anticoagulant (OAC) use (overall, warfarin, direct oral anticoagulants (DOACs)) and identify factors associated with oral anticoagulant use among the general population of residents living in nursing homes.

METHODS

This point prevalence study was conducted among 506,482 residents in US nursing homes on 31 October 2016 who were enrolled in Medicare fee-for-service. Covariates including demographics, clinical conditions, medications, cognitive impairment and functional status were obtained from Minimum Data Set 3.0 assessments and Medicare Part A and D claims. Oral anticoagulant use was identified using dispensing dates and days supply information from Medicare Part D claims. Robust Poisson models estimated adjusted prevalence ratios (aPR) for associations between covariates and 1) any anticoagulant use, and 2) DOAC versus warfarin use.

RESULTS AND DISCUSSION

Overall, 11.8% of residents used oral anticoagulants. Among users, 44.3% used DOACs. Residents with body mass index (BMI) ≥40 kg/m² (aPR: 1.66; 95% CI: 1.61 -1.71), with functional dependency in activities of daily living, polypharmacy and higher CHA₂ DS₂ -VASc risk ischaemic stroke scores, had a higher prevalence of oral anticoagulant use. Women (aPR: 0.78; 95% CI: 0.76-0.79), residents with limited life expectancy (aPR 0.80; 95% CI: 0.76-0.83), those with moderate-to-severe cognitive impairment (aPR: 0.67; 95% CI: 0.65-0.68), those using NSAIDs or antiplatelets, and non-white racial/ethnic groups had a lower prevalence of anticoagulant use. Residents with higher levels of polypharmacy, BMI and age had a lower prevalence of DOAC use (versus warfarin).

WHAT IS NEW AND CONCLUSION

Approximately one in eight general nursing home residents use oral anticoagulants and among oral anticoagulant users, only slightly more residents used warfarin than DOACs. The lower prevalence of anticoagulation among women and non-white racial/ethnic groups raises concerns of potential inequities in quality of care. Lower oral anticoagulant use among residents with limited life expectancy suggests possible deprescribing at the end of life. Further research is needed to inform resident-centred shared decision-making that explicitly considers treatment goals and individual-specific risks and benefits of anticoagulation at all stages of the medication use continuum.

Reducing length of stay with the direct oral anti-coagulants in low and intermediate risk pulmonary embolism: a single center experience

Direct oral anti-coagulants (DOACs) reduce hospital length-of-stay (LOS) in patients with acute pulmonary embolism (PE) in clinical trials. There is a paucity of literature describing real world utility of DOACs, particularly in intermediate-risk patients. To evaluate if the utilization of DOACs vs. non-DOACs in acute PE patients, reduces LOS without a difference in safety in patients defined as low and intermediate-risk of mortality by the European Society of Cardiology. This was a retrospective cohort study of prospectively collected data from a single center registry of consecutive adult outpatients diagnosed with acute PE who survived to hospital discharge. Primary outcome was median hospital LOS. Secondary outcomes were 30-day readmission, survival, and incidence of major and minor bleeding. There were 307 outpatients admitted with acute PE 88 (28.7%) low-risk, 213 (69.4%) intermediate-risk, and 6 (2.0%) high-risk. Two hundred and twenty-six (73.6%) received a DOAC. There was a statistically significant shorter median LOS in all patients treated with a DOAC (2.9 days, IQR 1.8-4.7) vs non-DOAC (4.9 days, IQR 3-8.9) (Generalized Linear Model p < 0.001). There was a shorter median LOS between intermediate-risk patients treated with a DOAC (3.6 days, IQR 2-5.8) vs non-DOAC (5, IQR 3-9). There was no difference in 30-day readmission, survival, or bleeding complications in both cohorts. There was a reduction in LOS in low and intermediate risk patients treated with a DOAC without a difference in 30-day safety and efficacy. Treating acute PE patients with DOACs including intermediate-risk patients, compared to conventional anticoagulation, may facilitate early discharge, and potentially reduce hospital costs.

Drug-Drug Interactions Leading to Adverse Drug Reactions with Rivaroxaban: A Systematic Review of the Literature and Analysis of VigiBase

Rivaroxaban has become an alternative to vitamin K antagonists, which are considered to be at higher risk of drug-drug interactions (DDI) and more difficult to use. However, DDI do occur. We systematically reviewed studies that evaluated them and analysed DDI and subsequent adverse drug reactions (ADR) reported in spontaneous reports and VigiBase. We systematically searched articles that explored DDI with rivaroxaban up to 20 August 2018 via Medline, Embase and Google Scholar. Data from VigiBase came from spontaneous reports recovered up to 2 January 2018, where Omega was used to detect signals and identify potential interactions in terms of triplets with two drugs and one ADR. We identified 31 studies and 28 case reports. Studies showed significant variation in the pharmacokinetic for rivaroxaban, and an increased risk of haemorrhage or thromboembolic events due to DDI was highlighted in case reports. From VigiBase, a total of 21,261 triplets were analysed and the most reported was rivaroxaban–aspirin–gastrointestinal haemorrhage. In VigiBase, only 34.8% of the DDI reported were described or understood, and most were pharmacodynamic DDI. These data suggest that rivaroxaban should be considered to have significant potential for DDI, especially with CYP3A/P-gp modulators or with drugs that impair haemostasis.

Safety of direct oral anticoagulants in patients with mild to moderate cirrhosis: a systematic review and meta-analysis

To evaluate major bleeding in cirrhosis with use of traditional anticoagulation or direct oral anticoagulants (DOACs), using a standardized definition. Anticoagulation in patients with cirrhosis is often a clinical conundrum for providers as the necessary balance between thrombotic and bleeding risk is complicated by end organ damage. Recent meta-analyses have sought to evaluate the safety and efficacy of direct oral anticoagulants in patients with liver disease. These recent analyses are limited by various bleeding definitions, broad inclusion criteria, and few indications for anticoagulation. We sought to conduct a meta-analysis using a validated definition for major bleeding and compare rates between traditional anticoagulation and DOACs in patients with cirrhosis. Articles were eligible for inclusion if the international society on thrombosis and hemostasis (ISTH) definition of a major bleed was the primary safety outcome. Additionally, only articles including patients with cirrhosis and receiving treatment with anticoagulation for an indication for stroke prevention or venous thromboembolism were eligible. Eligible articles needed a DOAC comparator group against traditional anticoagulant medication. Seven studies met inclusion criteria and compiled data for 683 patients in the meta-analysis. Pooled trial analysis demonstrated no statistically significant difference in the primary outcome of ISTH major bleeding (OR 0.55, 95%CI 0.28-1.07, I² 0%). Individual secondary outcomes of all bleeding, intracerebral hemorrhage, or gastrointestinal bleeding also demonstrated no significant difference between DOACs and traditional anticoagulation. Use of DOACs in patients with mild to moderate cirrhosis carries similar risk to use of traditional anticoagulation.

Anticoagulation clinic drive-up service during COVID-19 pandemic in Qatar

Coronavirus Disease 2019 (COVID-19) is a pandemic affecting many countries worldwide. Given the increasing incidence especially in elderly and individuals with comorbid conditions, it is advised by health authorities to stay home if possible, maintain social distancing and stay away from those who are sick or could be infected. Patients with comorbidities especially cardiovascular disease are at higher risk of getting infected with COVID-19 and have worse prognosis. Among efforts to safely manage warfarin patients during this pandemic, we introduced a hospital drive-up anticoagulation testing service. This service can reduce the risk of exposure of anticoagulation patients to COVID-19 by reducing the contact time with the different personnel at the hospital and by maintaining those patients at a safe distance from others

Patterns of anticoagulation therapy in atrial fibrillation: results from a large real-life single-center registry

Aim

To investigate the differences in the characteristics and clinical outcomes of recently diagnosed patients with atrial fibrillation (AF) receiving different types of anticoagulants in a real-life setting.

Methods

We retrospectively analyzed the charts of 1000 consecutive patients with non-valvular AF diagnosed and referred for hospitalization at our institution from 2013 to 2018.

Results

Over the observed period, the frequency of direct oral anticoagulation (DOAC) therapy use significantly increased (P = 0.002). Patients receiving warfarin had more unfavorable thromboembolic and bleeding risk factors than patients receiving DOAC. Predetermined stroke and major bleeding risks were similarly distributed among the dabigatran, rivaroxaban, and apixaban groups. Patients receiving warfarin had shorter time-to-major bleeding (TTB), time to thrombosis (TTT), and overall survival (OS) than patients receiving DOACs. After adjustment for factors unbalanced at baseline, the warfarin group showed significantly shorter OS (hazard ratio 2.27, 95% confidence interval 1.44-3.57, P < 0.001], while TTB and TTT did not significantly differ between the groups. Only 37% of patients on warfarin had optimal dosing control, and they did not differ significantly in TTB, TTT, and OS from patients on DOACs.

Conclusion

Warfarin and DOACs are administered to different target populations, possibly due to socio-economic reasons. Patients receiving warfarin rarely obtain optimal dosing control, and experience significantly shorter survival compared with patients receiving DOACs.

Research Trends in Anticoagulation Therapy over the Last 25 Years

A large volume of literature has become available to practitioners prescribing anticoagulants. The aim of this study was to analyze the bibliometric characteristics of the top 100 most cited articles related to anticoagulation over the past 25 years, with special consideration to impact of direct or "nonvitamin K antagonist" oral anticoagulants (NOACs) compared with vitamin K antagonists. A bibliometric analysis of the 100 most cited journal articles related to anticoagulants published between 1994 and 2019 was performed in April 2019. The top 100 articles by citation count were analyzed to extract bibliometric data related to journal title, impact factor, year of publication, place of publication, anticoagulant studied, indication for anticoagulation, study design, and conflicts of interest. The median (interquartile range) number of citations per article was 806 (621-1,085). The anticoagulant most frequently researched was warfarin (37%). NOAC publications (21%) grew at a relative rate of 3.4 times faster compared with all publications. The indication most commonly researched was venous thromboembolism (26%). Eighty articles constituted level I or II evidence, with randomized controlled trials the most common type of study (74). A financial conflict of interest was declared in 87% of articles with private, for-profit organizations the most common source of funding (26%). In summary, top research related to anticoagulation is highly impactful but may be at risk of sponsorship bias. High-level evidence for NOACs continues to expand across a range of indications with citation metrics likely to soon approach or surpass that of older drugs.

Select Drug-Drug Interactions With Direct Oral Anticoagulants: JACC Review Topic of the Week

Millions of individuals in the United States require long-term treatment with an oral anticoagulant. For decades, vitamin K antagonists were the only oral option available; however, they have a number of well-known limitations. Introduction of the direct oral anticoagulants (DOACs) has long been considered a major therapeutic advance, largely because they lack the need for therapeutic monitoring. Despite this, DOACs, like vitamin K antagonists, can still cause major and clinically relevant nonmajor bleeding, even when used appropriately. Drug-drug interactions (DDIs) involving the DOACs represent an important contributor to increased bleeding risk. Awareness of these DDIs and how best to address them is of critical importance in optimizing management while mitigating bleeding risk. This review provides an overview of DOAC metabolism, the most common drugs likely to contribute to DOAC DDIs, their underlying mechanisms, and how best to address them.

Uninterrupted direct oral anticoagulant treatment during acute illness: Impact on clinical outcomes

BACKGROUND

Uninterrupted drug therapy during acute illness is often associated with pharmacokinetic and pharmacodynamic variations. Among warfarin treated patients, these changes are reflected in the INR. However, in the case of direct oral anticoagulants (DOACs), given that routine laboratory monitoring is not recommended, these changes may result in unforeseen thromboembolic or bleeding events.

OBJECTIVES

To determine the rate of thromboembolic (TEE) and bleeding events associated with uninterrupted DOAC compared to warfarin treatment during acute illness.

METHODS

A retrospective cohort study of patients treated with DOACs or warfarin, both at steady state, who were hospitalized for acute illness. Primary outcome was any TEE or major bleeding requiring re-hospitalization within one month from discharge. Secondary outcome was a composite of major bleeding and clinically relevant non-major bleeding (CRNMB) events.

RESULTS

A total of 410 patients continued oral anticoagulant treatment during their hospitalization, of whom 191 (46.6%) were on DOACs and 219 (53.4%) on warfarin, with a total of 18 (4.4%) events. Rates of TEE and major bleeding events did not differ between DOACs and warfarin treated patients (0.9% vs. 0.5% and 0.5% vs. 1%, respectively). Similarly, rate of secondary outcome was comparable between DOACs (4.7%) and warfarin (2.7%, p = 0.29). Sub-analyses demonstrated significantly higher rates among rivaroxaban (10.4%) treated patients compared to warfarin (p = 0.03).

CONCLUSION

Uninterrupted treatment with DOACs during acute illness is not associated with increased risk for re-hospitalizations due to bleeding or thromboembolic events compared to warfarin. Our results suggest a higher bleeding rate among rivaroxaban treated patients at high bleeding risk.

Twice- or Once-Daily Dosing of Direct Oral Anticoagulants, a systematic review and meta-analysis

AIM

The direct oral anticoagulants (DOAC) have similar half-lives, but the dosing regimen varies between once daily (QD) or twice daily (BID). For some prescribers, the QD regimen improves compliance. Others prefer BID regimens to promote better stability of plasma concentrations, particularly in the event of missed doses. Limited level of evidence provides guidance about the best treatment strategy. The purpose of this study was to compare the treatment effect of QD vs. BID administration of DOACs in major orthopedic surgery (MOS), non-valvular atrial fibrillation (NVAF), venous thromboembolism (VTE), and acute coronary syndrome (ACS).

METHODS

We conducted a systematic review up to April 2020. We included phase II clinical trials comparing DOAC QD vs BID with same daily dose. We extracted data for the occurrence of major thrombosis (proximal deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke) and major hemorrhage (ISTH criteria and recommendations of the European Medicines Agency for surgical patients). Relative risks (RR) were combined using a fixed and random effects weighted meta-analysis.

RESULTS

Twelve randomized, controlled, phase II trials were included (10,716 patients), representing 24 dosing regimen comparisons of apixaban, darexaban, edoxaban, rivaroxaban, letaxaban, and dabigatran. There was no difference for major thrombotic event (RR_BID/QD = 1.06, 95%IC 0.86-1.30) nor for major bleeding (RR_BID/QD = 1.02, 95%IC 0.84-1.23) between the BID vs QD regimens, without heterogeneity (I² = 0%).

CONCLUSION

Our study does not support a global difference in term of efficacy and safety of the BID and QD regimens of DOAC in MOS, NVAF, VTE and ACS.

Patterns and factors influencing oral anticoagulant prescription in people with atrial fibrillation and dementia: Results from UK primary care

AIMS

Oral anticoagulant (OAC) is recommended for preventing stroke in atrial fibrillation (AF). However, the OAC utilisation in AF patients with dementia or cognitive impairment (CI) is limited. This study aimed to examine the prevalence of OAC prescriptions in AF patients with dementia/CI and to identify factors associated with OAC treatment within 180 days after dementia/CI diagnosis.

METHODS

Using The Health Improvement Network database, the annual trends of OAC between 2000 and 2015 were calculated. Multivariable logistic regression was performed to identify factors associated with OAC treatment.

RESULTS

The prevalence rate of OAC prescriptions increased from 6.1% in 2000 to 45.9% in 2015. Among OAC users, the proportion of direct oral anticoagulants (DOACs) use increased significantly from 0.1% in 2011 to 33.8% in 2015 (P-trend < 0.001), while the proportion of vitamin K antagonist use decreased by 28.6% from 100% in 2000 to 71.4% in 2015 (P-trend < 0.001). In the multivariable analysis, younger age, very old age, female sex, higher Charlson Comorbidity Index, having a HAS-BLED score ≥3, a history of intracranial bleeding, falls and polypharmacy were significantly associated with lower odds of receiving OAC.

CONCLUSIONS

In UK primary care, OAC use increased from 2000 to 2015 in AF patients with dementia/CI, with a substantial increase in use of DOACs. Characteristics related to frailty are associated with lower odds of OAC prescription. Given the increasing use of DOACs in patients with dementia/CI, further studies are needed to investigate the safety and effectiveness of DOACs in this important patient group.

Utilization of direct-acting oral anticoagulation in solid organ transplant patients: A national survey of institutional practices

The safety and efficacy of direct-acting oral anticoagulants (DOACs) and reversal strategies are not well established in the solid organ transplant population. This was a survey of pharmacists to assess DOAC and urgent reversal practices among adult transplant programs in the United States. A 27-question survey was distributed to members of transplant pharmacy organization listservs between 5/28/19 and 6/30/19. A total of 115 responses were received from kidney (43.5%), heart (20.0%), lung (18.3%), liver (13.9%), and pancreas (4.4%) transplant programs. DOAC use prior to transplant was mostly prohibited in thoracic programs (77.3%) but more permissive in kidney transplant programs (64.0%). If permitted, apixaban (57.8%) was most preferred. At transplant surgery, reversal of DOAC was performed "as needed" (20.9%) or was not routine (18.3%). DOAC use post-transplant was more permissive (94.3%). A majority of responders follow FDA recommended dosing in the setting of drug-drug interactions (51.1%). Major factors influencing DOAC prescribing decisions included renal function, drug-drug interactions, and insurance. High clinical practice variability exists regarding DOAC utilization and urgent reversal strategies in pre-, peri-, and post-transplant stages. While more research is needed to refine the clinical landscape, many institutions are using DOAC therapy under the perception that they pose a similar risk of bleeding compared to a non-transplant population.

Which patients with unprovoked venous thromboembolism should receive extended anticoagulation with direct oral anticoagulants? A systematic review, network meta-analysis, and decision analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) effectively prevent recurrent venous thromboembolism (VTE). However, it is unknown which agents should be used to prevent recurrent VTE and which patients with unprovoked VTE should receive extended anticoagulation. We therefore sought to compare the efficacy and safety among DOACs for secondary prevention of VTE. We also determined a risk-adapted threshold for initiating extended anticoagulation based on the likelihood of VTE recurrence (without treatment) and bleeding (with treatment) in patients with unprovoked VTE.

METHODS

Our systematic review of randomized controlled trials compares extended anticoagulation with DOACs to another DOAC, aspirin, or placebo for the prevention of recurrent VTE. We searched PubMed, EMBASE, and Cochrane Registry of Controlled Trials (CENTRAL) in October 2018. Our outcomes of interest were VTE recurrence, major bleeding, and all clinically relevant bleeding. We used network meta-analysis to make indirect comparisons among DOACs. We populated the threshold decision-analytic model with data from our meta-analysis to determine the risk of VTE recurrence above which the benefits of extended anticoagulation outweigh the harms compared with no treatment.

RESULTS

We included four, high-quality, randomized trials comprising 8386 participants. Low-dose apixaban, full-dose apixaban, low-dose rivaroxaban, full-dose rivaroxaban, and dabigatran reduce VTE recurrence compared with placebo (RR = 0.19, 95% CI, 0.12-0.31; RR = 0.20, 95% CI, 0.12-0.32; RR = 0.08, 95% CI, 0.03-0.27; RR = 0.14, 95% CI, 0.06-0.35; RR = 0.19, 95% CI, 0.09-0.40, respectively). No DOACs increased major bleeding risk compared with placebo. A VTE recurrence risk above 0.3% to 0.4% at approximately 1 year is the threshold to treat a patient with unprovoked VTE with extended anticoagulation (with any DOAC).

CONCLUSIONS

All DOACs exhibit comparable efficacy for the prevention of recurrent VTE. Given that the risk of VTE recurrence is much higher than the calculated threshold for treatment, extended thromboprophylaxis should be considered in all patients with unprovoked VTE who do not have increased bleeding risk.

Monitoring of atrial fibrillation in primary care patients prescribed direct oral anticoagulants for stroke prevention

BACKGROUND

Direct oral anticoagulants (DOACs) are widely marketed as medicines that do not require routine laboratory monitoring. However, they do have complex pharmacological properties and side effects; hence prescribing and monitoring guidelines, such as the European Heart Rhythm Association (EHRA) guidelines, have emerged. These advocate monitoring for renal and hepatic impairment; bleeding episodes; liver function; co-medication; circulation, and occurrence of side effects. Though 3 to 6 month follow-up is advocated, this is currently not routine, and its implementation creates a potential obligation for general practitioners (GPs) managing atrial fibrillation (AF) patients in the community.

AIMS

This study investigates the frequency, the type of follow-up, and the factors that influenced follow-up among Irish GPs, who prescribed DOACs to patients with AF, to prevent strokes in 2015.

METHODS

The frequency and type of follow-up care is estimated, and a count model regression analysis is applied to determine the GP and practice characteristics that are associated with the implementation of follow-up.

RESULTS

The EHRA guidelines most frequently followed were those pertaining to renal function (82%), bleeding episodes (71%), liver function (69%), circulation (54%), and side effects (55%). The regression analysis revealed that female GPs (P = 0.05) and GPs who follow all seven guidelines (P = 0.06) practice more frequent follow-up while those in training practices (P = 0.09) provide less frequent follow-up.

CONCLUSIONS

Results show that there was incomplete adherence to the 2013 EHRA prescribing guidelines with only 24% adhering to all seven guidelines, and patient follow-up was less frequent than has been suggested.

Non-vitamin K antagonist oral anticoagulants (NOACs) post-percutaneous coronary intervention: a network meta-analysis

BACKGROUND

Clinicians must balance the risks of bleeding and thrombosis after percutaneous coronary intervention (PCI) in people with an indication for anticoagulation. The potential of non-vitamin K antagonists (NOACs) to prevent bleeding complications is promising, but evidence remains limited.

OBJECTIVES

To review the evidence from randomised controlled trials assessing the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) compared to vitamin K antagonists post-percutaneous coronary intervention (PCI) in people with an indication for anticoagulation.

SEARCH METHODS

We identified studies by searching CENTRAL, MEDLINE, Embase, the Conference Proceedings Citation Index - Science and two clinical trials registers in February 2019. We checked bibliographies of identified studies and applied no language restrictions.

SELECTION CRITERIA

We searched for randomised controlled trials (RCT) that compared NOACs and vitamin K antagonists for people with an indication for anticoagulation who underwent PCI.

DATA COLLECTION AND ANALYSIS

Two review authors independently checked the results of searches to identify relevant studies, assessed each included study, and extracted study data. We conducted random-effects, pairwise analyses using Review Manager 5 and network meta-analyses (NMA) using the R package 'netmeta'. We ranked competing treatments by P scores, which are derived from the P values of all pairwise comparisons, and allow ranking of treatments on a continuous 0 to 1 scale.

MAIN RESULTS

We identified nine RCTs that met the inclusion criteria, but four were ongoing trials, and were not included in this analysis. We included five RCTs, with 8373 participants, in the NMA (two RCTs compared apixaban to a vitamin K antagonist, two RCTs compared rivaroxaban to a vitamin K antagonist, and one RCT compared dabigatran to a vitamin K antagonist). Very low- to moderate-certainty evidence suggests little or no difference between NOACs and vitamin K antagonists in death from cardiovascular causes (not reported in the dabigatran trial), myocardial infarction, stroke, death from any cause, and stent thrombosis. Apixaban (RR 0.85, 95% CI 0.77 to 0.95), high dose rivaroxaban (RR 0.86, 95% CI 0.74 to 1.00), and low dose rivaroxaban (RR 0.80, 95% CI 0.68 to 0.92) probably reduce the risk of recurrent hospitalisation compared with vitamin K antagonists. No studies looked at health-related quality of life. Very low- to moderate-certainty evidence suggests that NOACs may be safer than vitamin K antagonists in terms of bleeding. Both high dose dabigatran (RR 0.53, 95% CI 0.29 to 0.97), and low dose dabigatran (RR 0.38, 95% CI 0.21 to 0.70) may reduce major bleeding more than vitamin K antagonists. High dose dabigatran (RR 0.83, 95% CI 0.72 to 0.96), low dose dabigatran (RR 0.66, 95% CI 0.58 to 0.75), apixaban (RR 0,67 , 95% Cl 0.51 to 0.88), high dose rivaroxaban (RR 0.66, 95% CI 0.52 to 0.83), and low dose rivaroxaban (RR 0.71, 95% CI 0.57 to 0.88) probably reduce non-major bleeding more than vitamin K antagonists. The results from the NMA were inconclusive between the different NOACs for all primary and secondary outcomes.

AUTHORS' CONCLUSIONS

Very low- to moderate-certainty evidence suggests no meaningful difference in efficacy outcomes between non-vitamin K antagonist oral anticoagulants (NOAC) and vitamin K antagonists following percutaneous coronary interventions (PCI) in people with non-valvular atrial fibrillation. NOACs probably reduce the risk of recurrent hospitalisation for adverse events compared with vitamin K antagonists. Low- to moderate-certainty evidence suggests that dabigatran may reduce the rates of major and non-major bleeding, and apixaban and rivaroxaban probably reduce the rates of non-major bleeding compared with vitamin K antagonists. Our network meta-analysis did not show superiority of one NOAC over another for any of the outcomes. Head to head trials, directly comparing NOACs against each other, are required to provide more certain evidence.

Orthotopic Liver Transplant in a Patient Anticoagulated With Rivaroxaban: A Case Report

Direct oral anticoagulants are approved for use in the United States and Europe and are increasingly used in chronic liver disease patients who have or are at risk of thrombotic events. While these drugs are clinically attractive because no monitoring is required, the risks and benefits in patients with hepatic or renal insufficiency who undergo surgery remain unclear. In this report, we describe the perioperative consequences, safety issues, and lessons learned from a patient undergoing an orthotopic liver transplant who was anticoagulated with rivaroxaban due to partial superior mesenteric vein thrombosis.

Anticoagulant Utilization and Direct Oral Anticoagulant Prescribing in Patients with Nonvalvular Atrial Fibrillation

BACKGROUND

Direct oral anticoagulants (DOACs) are indicated for prevention of stroke and embolism in patients with nonvalvular atrial fibrillation (NVAF). These agents have been shown to be non-inferior to warfarin in terms of efficacy and safety. However, their uptake in practice has been variable, and prescribed dosages may be inconsistent with manufacturer recommendations.

OBJECTIVES

To evaluate patterns of oral anticoagulant use in patients with NVAF, including determination of patient characteristics associated with the prescribing of warfarin or DOACs and whether prescribed dosages of DOACs were concordant with manufacturer recommendations.

METHODS

This retrospective chart review was conducted from April to September 2017 at Abbotsford Regional Hospital, Abbotsford, British Columbia. Patients at least 18 years of age with NVAF and CHADS-65 score of 1 or higher were included. Patients with contraindications to oral anticoagulants, those with reversible atrial fibrillation, and those undergoing renal dialysis were excluded. The dosage of DOACs was categorized as too low, too high, or correct in relation to manufacturer recommendations for the Canadian product.

RESULTS

A total of 120 patients were included. At discharge, 83 (69%) of the patients had a prescription for DOAC, 25 (21%) had a prescription for warfarin, and 12 (10%) had no prescription for an oral anticoagulant. There were no statistically significant differences between the warfarin and DOAC groups with respect to patient characteristics. Among the 56 patients for whom a full DOAC dose was indicated, 7 (13%) received a dose that was too low. Among the 23 patients for whom a full DOAC dose was not indicated, 4 (17%) received a dose that was too high.

CONCLUSIONS

At the study hospital, most patients with NVAF and CHADS-65 score of at least 1 had a discharge prescription for DOAC. Patient characteristics appeared to be similar between the warfarin and DOAC groups. For a notable proportion of patients who received a DOAC, the dosage was incorrect. Appropriate prescribing of oral anticoagulants could be further improved by education for prescribers and involvement of hospital pharmacists.

A New Test for the Detection of Direct Oral Anticoagulants (Rivaroxaban and Apixaban) in the Emergency Room Setting

Determining whether a patient has taken a direct oral anticoagulant (DOAC) is critical during the periprocedural and preoperative period in the emergency department. However, the inaccessibility of complete medical records, along with the generally inconsistent sensitivity of conventional coagulation tests to these drugs, complicates clinical decision making and puts patients at risk of uncontrollable bleeding. In this study, we evaluate the utility of inhibitor-II-X (i-II-X), a novel, microfluidics-based diagnostic assay for the detection and identification of Factor Xa inhibitors (FXa-Is) in an acute care setting.

DESIGN

First-in-human, 91-patient, single-center retrospective pilot study.

SETTING

Emergency room.

PATIENTS

Adult patients admitted into the emergency department, which received any clinician-ordered coagulation test requiring a 3.2% buffered sodium citrate blood collection tube.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma samples from patients admitted to the emergency department were screened for the use of FXa-Is, including apixaban and rivaroxaban, within the past 24 hours using our new i-II-X microfluidic test. i-II-X results were then compared with results from conventional coagulation tests, including prothrombin time (PT) and international normalized ratio (INR), which were ordered by treating clinicians, and an anti-Xa assay for rivaroxaban. The i-II-X test detected DOACs in samples collected from the emergency department with 95.20% sensitivity and 100.00% specificity. Unlike PT and INR, i-II-X reliably identified patients who had prolonged clotting times secondary to the presence of a FXa-I.

CONCLUSIONS

The i-II-X test overcomes the limitations of currently available coagulation tests and could be a useful tool by which to routinely screen patients for DOACs in emergency and critical care settings. Our new diagnostic approach is particularly relevant in clinical situations where medical records may be unavailable, or where precautions need to be taken prior to invasive interventions, such as specific reversal agent administration.

Reversal of direct oral anticoagulants: Guidance from the Anticoagulation Forum

Two specific reversal agents for direct oral anticoagulants (DOACs) have been approved in the United States: idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. Non-specific prohemostatic agents such as prothrombin complex concentrate (PCC) and activated PCC have also been used for DOAC reversal. The goal of this document is to provide comprehensive guidance from the Anticoagulation Forum, a North American organization of anticoagulation providers, regarding use of DOAC reversal agents. We discuss indications for reversal, provide guidance on how the individual reversal agents should be administered, and offer suggestions for stewardship at the health system level.

Bleeding assessment in oral surgery: A cohort study comparing individuals on anticoagulant therapy and a non-anticoagulated group

Some prospective studies have been designed specifically to investigate perioperative bleeding in dental surgery. The quantitative assessment of intraoperative blood loss can be useful for indicating the real risk of bleeding complications, especially in medically compromised individuals. The aim of this study was to evaluate the pattern of bleeding in individuals under vitamin K antagonist (VKA) therapy and non-anticoagulated individuals submitted to dental extractions. Perioperative bleeding was evaluated by using a total collected bleeding corrected by absorbance reading (dental bleeding score). 138 procedures were performed. When the perioperative dental bleeding score was correlated with the number of extracted teeth, the quantity of bleeding was found to be directly proportional to the procedure. Extractions of two or more teeth presented higher scores than single extractions (p = 0.003). In a comparative analysis between the VKA and non-anticoagulated groups, no significant difference in the scores was found. The previous history of complications in dental procedures (p = 0.001) and the use of additional hemostatic measures were higher in the VKA group (p = 0.017). VKA therapy did not impact significantly the volume of blood lost during dental extractions. Perioperative bleeding assessment might be a useful parameter for evaluating patients under antithrombotic treatment.

Use of direct oral anticoagulants in the treatment of left ventricular thrombi: A tertiary center experience and review of the literature

Direct oral anticoagulants can potentially provide a more convenient oral alternative for the management of left ventricular thrombi than Warfarin. These medications do not require frequent monitoring and have less drug-drug interactions. Randomized controlled trials are needed to further demonstrate their efficacy and safety in this setting.

Effectiveness and safety of apixaban versus rivaroxaban for prevention of recurrent venous thromboembolism and adverse bleeding events in patients with venous thromboembolism: a retrospective population-based cohort analysis

BACKGROUND

Apixaban and rivaroxaban, both direct-acting oral anticoagulants, are being increasingly used in routine clinical practice because of their fixed dosing and favourable pharmacological profiles. Differences in the risk of recurrent venous thromboembolism and major bleeding events between the two drugs are currently unknown. We aimed to compare the effectiveness and safety of apixaban and rivaroxaban in prevention of recurrent venous thromboembolism and major bleeding events in patients with venous thromboembolism.

METHODS

We did a retrospective cohort analysis of data from the Truven Health MarketScan commercial and Medicare Supplement claims databases in the USA. We analysed data for adult patients with newly diagnosed venous thromboembolism (deep vein thrombosis or pulmonary embolism) who were new users of apixaban or rivaroxaban between Jan 1, 2014, and Dec 31, 2016. Patients who did not initiate the study drugs within 30 days of their diagnosis, those without 12 months of continuous enrolment in medical and pharmacy benefits, and those who used other anticoagulants during the baseline period were excluded. The primary effectiveness outcome was the incidence of recurrent venous thromboembolism and the primary safety outcome was the incidence of major bleeding events. Cox-proportional hazard models after propensity score matching were used to calculate the hazard ratio (HR) and 95% CI.

FINDINGS

After propensity score matching, 15 254 patients were included in the cohort (3091 apixaban users and 12 163 rivaroxaban users). The crude incidence of recurrent venous thromboembolism was three per 100 person-years in the apixaban group and seven per 100 person-years in the rivaroxaban group. The incidence of major bleeding was three per 100 person-years in the apixaban group and six per 100 person-years in the rivaroxaban group. In multivariable Cox regression models, the use of apixaban compared with rivaroxaban was associated with decreased risk of recurrent venous thromboembolism (HR 0·37 [95% CI 0·24-0·55]; p<0·0001) and major bleeding events (0·54 [0·37-0·82]; p=0·0031).

INTERPRETATION

Based on our findings, apixaban seems to be more effective than rivaroxaban in preventing the development of recurrent venous thromboembolism and major bleeding events. Our data might give some assurance to clinicians that apixaban can be an effective and safe therapeutic option for treatment of patients with venous thromboembolism.

FUNDING

None.

Effectiveness and Safety of Apixaban versus Warfarin as Outpatient Treatment of Venous Thromboembolism in U.S. Clinical Practice

In the AMPLIFY clinical trial, apixaban was non-inferior to warfarin plus subcutaneous enoxaparin bridge therapy in the treatment of acute venous thromboembolism (VTE) and was associated with significantly less bleeding. This study evaluated their comparative effectiveness and safety in routine clinical practice. A matched-cohort design and data from four U.S. private health care claims databases were employed. Study population comprised patients who initiated outpatient treatment with apixaban versus warfarin (plus parenteral anticoagulant bridge therapy) within 30 days of their initial VTE episode; apixaban and warfarin patients were matched on age, characteristics of VTE episode, study database and propensity score. Major bleeding, clinically relevant non-major (CRNM) bleeding and recurrent VTE during the 180-day (maximum) follow-up period were compared using shared frailty models. During mean follow-up of 143 days among apixaban patients (n = 17,878) and 152 days among warfarin patients (n = 17,878), incidence proportions for apixaban versus warfarin, respectively, were 1.7% versus 2.3% for major bleeding, 7.0% versus 9.4% for CRNM bleeding and 2.3% versus 2.9% for recurrent VTE. In shared frailty models, risks of major bleeding (hazard ratio [HR] = 0.75, 95% confidence interval [CI] = 0.64-0.87), CRNM bleeding (HR = 0.77, 95% CI = 0.71-0.83) and recurrent VTE (HR = 0.80, 95% CI = 0.70-0.91) were lower for apixaban versus warfarin. In this large-scale evaluation of VTE patients receiving outpatient treatment with apixaban or warfarin in U.S. clinical practice, risks of major bleeding, CRNM bleeding and recurrent VTE were significantly lower among patients who received apixaban.

A Survey on the Awareness and Attitude of Physicians on Direct Oral Anticoagulants in Qatar

Direct oral anticoagulants (DOACs) are more commonly prescribed since their introduction. Reports on inappropriate prescribing have been observed which may indicate poor awareness on these agents. In this study, we aim to evaluate the extent of the physicians' knowledge on DOACs and its possible impact on physicians' confidence to prescribe these medications. A prospective cross-sectional survey was developed based on the literature review. Eligible participants were physicians and surgeons currently practicing at Hamad General Hospital in Qatar. The survey included questions on demographic and professional characteristics. It also evaluated the awareness and attitudes regarding safety, efficacy, and prescribing of DOACs. Over 6-month period, 175 practitioners responded to the survey. Overall awareness score was moderate (61% ± 18%). These scores were in alignment with participants' self-satisfaction with knowledge on DOACs (66% were not satisfied) and participants' confidence toward prescribing DOACs (48% were not confident). Age, degree of education, and years of experience had significant positive influence on awareness score. This survey indicates that practitioners have moderate awareness on DOACs. Future work should focus on reassessing practitioners' knowledge after providing well-designed education campaigns.

The vexed question of whether or not to measure levels of direct oral anticoagulants before surgery or invasive procedures

Direct oral anticoagulants (DOAC) possess high bioavailability, and their anticoagulant effect is more predictable than that of vitamin K antagonists, hence they do not require routine dose adjustment based on laboratory testing. However, there are circumstances when laboratory testing may be useful, including patients who need to undergo surgery or invasive procedures. Most guidelines state that patients on DOAC may safely undergo surgery/invasive procedures by stopping anticoagulation for a few days before intervention without testing if renal function is within normal limits. This review article discusses the pros and cons of measuring (or not measuring) DOAC levels before surgery/invasive procedures by a multidisciplinary team of experts with different background, including the thrombosis laboratory, clinical thrombosis, internal medicine, cardiology and nephrology. The conclusion is that measuring DOAC with dedicated tests before surgical or invasive procedures is important for patient safety. It provides the best and most direct evidence to rule in (or to rule out) clinically relevant concentrations of residual drugs. Regulatory agencies should urgently approve their use in clinical practice. Hospital administrators should make them available, and clinical laboratories should set up the relative methods and make them available to clinicians.

Direct oral anticoagulants: A retrospective study of bleeding, behavior, and documentation

OBJECTIVE

To examine the effects of direct oral anticoagulants (DOACs) on bleeding complications following dental surgeries.

SUBJECTS AND METHODS

This 6-year retrospective study collected data from records of patients undergoing oral surgical procedures within a university setting. An electronic health record database was searched using current procedural terminology codes for oral surgical procedures. Information regarding patient, procedural factors, and postoperative complications were extracted. Data were analyzed by Fisher's exact test.

RESULTS

Of patients who had a procedural code associated with oral surgery, only 0.11% (12/11,320) took a DOAC. Twelve patients (10 males, age ranging from 44 to 90 years) underwent 17 surgeries by nine different practitioners involving 98 extractions, 14 alveoloplasties, two tuberosity reductions, and two tori removals. In nine cases, the DOAC was discontinued a mean of 52.5 hrs prior to surgery (range 12-120 hrs). Bleeding complications were not reported for patients whose drug was discontinued or continued. Documentation of drug continuation/discontinuation was poor.

CONCLUSIONS

Bleeding was not observed with direct oral anticoagulation use in this oral surgery cohort. Drug discontinuation/continuation was not a factor in bleeding outcomes, and direct oral anticoagulation interruption was variable and poorly documented.

Position Paper on laboratory testing for patients on direct oral anticoagulants. A Consensus Document from the SISET, FCSA, SIBioC and SIPMeL

Although direct oral anticoagulants (DOAC) do not require dose-adjustment on the basis of laboratory test results, the measurement of their anticoagulant effect is useful in special situations. This position paper issued by the Italian Scientific Societies that are mainly involved in the management of patients on DOAC is aimed at providing guidance to care-givers on which tests should be used and the situations in which testing is useful. The guidance is based on the data from the literature so far available and/or on consensus among experts.

Pharmacogenetic studies with oral anticoagulants. Genome-wide association studies in vitamin K antagonist and direct oral anticoagulants

Oral anticoagulants (OAs) are the recommended drugs to prevent cardiovascular events and recurrence in patients with atrial fibrillation (AF) and cardioembolic stroke. We conducted a literature search to review the current state of OAs pharmacogenomics, focusing on Genome Wide Association Studies (GWAs) in patients treated with vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs).

VKAs: Warfarin, acenocoumarol, fluindione and phenprocoumon have long been used, but their interindividual variability and narrow therapeutic/safety ratio makes their dosage difficult. GWAs have been useful in finding genetic variants associated with VKAs response. The main genes involved in VKAs pharmacogenetics are: VKORC1, CYP2C19 and CYP4F2. Variants in these genes have been included in pharmacogenetic algorithms to predict the VKAs dose individually in each patient depending on their genotype and clinical variables.

DOACs: Dabigatran, apixaban, rivaroxaban and edoxaban have been approved for patients with AF. They have stable pharmacokinetics and do not require routine blood checks, thus avoiding most of the drawbacks of VKAs. Except for a GWAs performed in patients treated with dabigatran, there is no Genome Wide pharmacogenomics data for DOACs. Pharmacogenomics could be useful to predict the better clinical response and avoid adverse events in patients treated with anticoagulants, identifying the most appropriate anticoagulant drug for each patient. Current pharmacogenomics data show that the polymorphisms affecting VKAs or DOACs are different, concluding that personalized medicine based on pharmacogenomics could be possible. However, more studies are required to implement personalized medicine in clinical practice with OA and based on pharmacogenetics of DOACs.

Management of venous thromboembolism with non-vitamin K oral anticoagulants: A review for nurse practitioners and pharmacists

BACKGROUND AND PURPOSE

Venous thromboembolism (VTE), comprising deep-vein thrombosis and pulmonary embolism, is associated with significant morbidity and mortality. Non-vitamin K oral anticoagulants (NOACs), including apixaban, betrixaban, dabigatran, edoxaban, and rivaroxaban, are as effective and safe as vitamin K antagonists (VKAs) for primary prophylaxis, treatment, and/or secondary prevention of VTE and present significant advantages in convenience of use. This review provides guidance to nurse practitioners (NPs) and pharmacists on NOAC usage for the management of VTE and examines how traditional anticoagulation clinics can adapt to cater to patients on NOACs.

METHODS

A review of the scientific literature pertaining to treatment guideline recommendations, large randomized clinical trials, and real-world evidence studies related to VTE management was conducted.

CONCLUSIONS

With current data suggesting that NOACs may present as better alternatives over VKAs for the management of VTE, comprehensively educating NPs and pharmacists can help incorporate these agents in their clinical practice.

IMPLICATIONS FOR PRACTICE

Repurposing anticoagulation clinics, led by well-informed NPs and pharmacists, will allow effective integration and optimal management of patients with VTE taking NOACs as well as those taking VKAs.

Management of pulmonary embolism after recent intracranial hemorrhage: A case report

RATIONALE

Venous thromboembolism may result from prolong immobilization following intracerebral hemorrhage. Massive pulmonary embolism with associated right heart failure is life-threatening, requiring treatment with anticoagulants or even thrombolytic agents. However, these drugs are contraindicated after a recent hemorrhagic episode, as they may induce further hemorrhage. There are no guidelines for treatment in these circumstances.

PATIENT CONCERNS

A 57-year-old man experienced massive pulmonary embolism and shock 18 days after an intracerebral hemorrhage.

DIAGNOSES

Tachycardia and high D-dimer (21.27 mg/L fibrinogen-equivalent units) were noted. Chest computed tomography showed bilateral pulmonary trunk embolism.

INTERVENTIONS

Heparinization were used and activated partial thromboplastin time therapeutic range was 50 to 70 seconds. Fortunately, shock status and shortness of breath improved two days later. Continuing high dose Rivaroxaban was administrated for three weeks.

OUTCOMES

There was no recurrent intracranial hemorrhage (ICH) following treatment for three-weeks with high-dose and one-year with standard dose of rivaroxaban. This report presents a treatment option in the management of these difficult clinical situations.

LESSONS

The combination of unfractionated heparin infusion and continuing non-Vitamin K antagonist oral anticoagulants use could manage life-threatening pulmonary embolism following recent ICH. Theoretically, the use of NOAC is a safer strategy if the patient with previous history of major ICH.