Bleeding with Direct Oral Anticoagulants vs Warfarin: Clinical Experience

Recommendations for the safe use of direct oral anticoagulants in patients with cirrhosis based on a systematic review of pharmacokinetic, pharmacodynamic and safety data

PURPOSE

The popularity of direct oral anticoagulants (DOACs) is increasing among patients with cirrhosis. Cirrhosis has a major impact on the pharmacokinetics of drugs, potentially increasing adverse events. Safe use of drugs in cirrhosis requires a diligent risk-benefit analysis. The aim of this study is to develop practice recommendations for safe use of DOACs in cirrhosis based on a systematic review of pharmacokinetic, pharmacodynamic and safety data.

METHODS

We conducted a systematic literature search to identify studies on pharmacokinetics, pharmacodynamics and safety of DOACs in cirrhosis. Data were collected and presented in summary tables by severity of cirrhosis using the Child-Turcotte-Pugh (CTP) classification. A multidisciplinary expert panel evaluated the results and classified the DOACs according to safety.

RESULTS

Fifty four studies were included. All DOACs were classified as 'no additional risks known' for CTP A. For CTP B, apixaban, dabigatran and edoxaban were classified as 'no additional risks known'. Apixaban and edoxaban showed fewer adverse events in patients with cirrhosis, while dabigatran may be less impacted by severity of cirrhosis based on its pharmacokinetic profile. Rivaroxaban was classified as 'unsafe' in CTP B and C based on significant pharmacokinetic alterations. Due to lack of data, apixaban, dabigatran and edoxaban were classified as 'unknown' for CTP C.

CONCLUSION

DOACs can be used in patients with CTP A cirrhosis, and apixaban, dabigatran and edoxaban can also be used in CTP B. It is recommended to avoid rivaroxaban in CTP B and C. There is insufficient evidence to support safe use of other DOACs in CTP C cirrhosis.

Effectiveness of Direct Oral Anticoagulants and Vitamin K Antagonists in Preventing Stroke in Patients With Atrial Fibrillation and Liver Cirrhosis: A Systematic Review and Meta-Analysis

Patients with atrial fibrillation and concurrent liver cirrhosis have been excluded from major clinical trials evaluating direct oral anticoagulants (DOACs) due to safety concerns. This has led to uncertainty regarding the optimal anticoagulant therapy in this population at high risk of thromboembolic events. We conducted a systematic review and meta-analysis to compare the effectiveness and safety of DOACs versus vitamin K antagonists (VKAs) in patients with atrial fibrillation and liver cirrhosis. Databases including Embase, MEDLINE/PubMed, and Web of Science were searched for relevant studies. The primary effectiveness outcome was stroke or systemic embolism, and the safety outcome was major bleeding events. A total of 10 studies were included in the meta-analysis. Compared to VKAs, the use of DOACs was associated with a significantly lower risk of stroke or systemic embolism (RR: 0.78, 95% CI: 0.65-0.92, p=0.005). The risk of all-cause mortality was comparable between the two groups (RR: 0.89, 95% CI: 0.74-1.07, p=0.23). Notably, DOACs demonstrated a significantly lower risk of major bleeding events (RR: 0.67, 95% CI: 0.61-0.73, p<0.01) compared to VKAs. This meta-analysis suggests that DOACs may be a favorable alternative to VKAs for the prevention of thromboembolic events in patients with atrial fibrillation and liver cirrhosis, with a lower risk of stroke or systemic embolism and major bleeding. However, further research is needed to establish optimal dosing strategies and assess the safety and efficacy of DOACs in patients with advanced liver disease.

Is anticoagulative therapy in systemic sclerosis to be reconsidered?

Systemic sclerosis is a rare disease with a high mortality rate. It is a multisystem connective tissue disease due to endothelial autoimmune activation along with tissue and vascular fibrosis, inducing vasculopathy, with an angiogenesis wasting. The endothelial damage provokes platelet activation and immune cell adhesion. The detachment of endothelial cells leads to the interaction of platelets and collagen present in the exposed subendothelial layer. This provokes the activation of several coagulative factors, inducing a pro-thrombotic condition by thrombin generation, which converts fibrinogen into fibrin. Moreover, thrombin has other functions, such as the induction of hyperplasia in smooth muscle cells and fibroblasts, thereby favouring fibrosis. An increased risk of venous thromboembolism has been found in systemic sclerosis, whereas pulmonary hypertension may be due to the obstruction of small pulmonary arteries. Pulmonary veno-occlusive disease may also occur. Warfarin showed inconsistent results, while the outcomes of a randomised, placebo-controlled clinical trial on apixaban versus placebo are still awaited. A new anticoagulation strategy based on anti-factor XI drugs is being developed, with the aim of achieving optimal anticoagulation along with a low risk of bleeding. The molecule types under investigation in this category include monoclonal antibodies, small molecules, natural inhibitors, antisense oligonucleotides, and aptamers. Patients with systemic sclerosis may be ideal candidates for clinical trials planned to analyse the efficacy and safety of these molecules.

Drug-related problems associated with direct oral anticoagulants: an observational cross-sectional study of medical record review by pharmacists in a large teaching hospital

Background

Prescribing DOACs presents with challenges in the elderly and patients with renal and hepatic impairment. To mitigate safety risks, pharmacists have a role in detection, prevention, and resolution of DOAC-associated drug-related problems (DRPs).

Objectives

To identify the types of DOAC-associated DRPs in patients on DOAC therapy and factors that predispose patients to DOAC-associated DRPs.

Methods

An observational cross-sectional study was conducted in SGH from January 1, 2017, to May 31, 2019, on patients prescribed with a DOAC (rivaroxaban, dabigatran, and apixaban). Data were electronically extracted for patient demographics, clinical characteristics, and details of DOAC-related DRPs identified by pharmacists. Matching of DRP group to non-DRP group at a ratio of 1:2 based on gender, race, and DOAC was performed. The DRP group included patients with detected DRPs while non-DRP group included patients without them. Descriptive analysis was used to summarize patient characteristics and types of DOAC-associated DRPs. In the matched population, conditional logistic regression was used to calculate unadjusted (UOR) and adjusted odds (AOR) ratio to detect association of DOAC-associated DRPs with age, renal function, ≥2 comorbidities, and DOAC indication (atrial fibrillation [AF] vs venous thromboembolism).

Results

A total of 8432 patients prescribed DOACs were analyzed, which consisted of 827 (9.8%) and 7602 (90.2%) patients with DRPs and no DRPs, respectively. The top DOAC-associated DRP was inappropriate drug regimen (n = 487, 60.1%). After matching, 2403 patients were analyzed, consisting of 801 patients from DRP group and 1602 from non-DRP group. Factors associated with DOAC-associated DRPs were statistically significant for renal function at creatinine clearance (CrCl) of >30 to 50 mL/min/1.73 m2 (AOR: 1.42; 95% CI: 1.14-1.76; P = .002), 15 to 30 mL/min/1.73 m2 (OR: 1.94; 95% CI: 1.42-2.66; P < .001), and <15 mL/min/1.73m2 (OR: 2.35; 95% CI: 1.13-4.88; P = .022), respectively, compared with a CrCl of >50 mL/min/1.73 m2 and DOAC indication for AF (AOR: 1.84; 95% CI: 1.47-2.30; P < .001) compared with venous thromboembolism.

Conclusion

Inappropriate drug regimen was the most common DOAC-associated DRP. Impaired renal function and patients with AF increased the likelihood of DOAC-associated DRPs.

ABCG2 Gene Polymorphisms May Affect the Bleeding Risk in Patients on Apixaban and Rivaroxaban

Purpose

Direct oral anticoagulants (DOACs) are widely used for stroke prevention in atrial fibrillation. However, they have a bleeding complication. Breast cancer resistance protein, encoded by ABCG2, is known to be an efflux transporter of apixaban and rivaroxaban among DOACs. This study aimed to investigate the association between gene variants and bleeding complications during treatment with ABCG2 substrates (apixaban and rivaroxaban).

Patients and Methods

Patients treated with apixaban and rivaroxaban were enrolled from June 2018 to December 2021. Five single nucleotide polymorphisms (SNPs) of ABCG2 were selected. Previously studied genes (ABCB1, CYP3A4, and CYP3A5) were further analyzed as possible confounders. Finally, a total of 16 SNPs were examined in this case-control study. The outcome was defined as major bleeding and clinically relevant non-major bleeding. Two models were constructed using the multivariable analysis.

Results

Among 293 patients, 64 were cases. The mean age of the patients was 68.8 years, and males comprised 62.5% of the study population. Model I revealed that a history of bleeding, concurrent use of proton pump inhibitor (PPI), ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with bleeding complications; the AORs (95% CI) were 6.209 (2.210-17.442), 2.385 (1.064-5.349), 2.188 (1.156-4.142), and 3.243 (1.371-7.671), respectively. Model II showed that modified HAS-BLED score, concurrent use of PPI, ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with bleeding complications.

Conclusion

The modified HAS-BLED score, a history of bleeding, concurrent use of PPI, ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with the risk of bleeding complications in patients on apixaban and rivaroxaban, after adjusting for other confounders. These findings can be used to develop individualized treatment strategies for patients taking apixaban and rivaroxaban.

Generic Methods for Simultaneous Analysis of Four Direct Oral Anticoagulants in Human Plasma and Urine by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

The new direct oral anticoagulants (DOACs) are increasingly used to treat and prevent thromboembolic disorders, and monitoring concentrations may be valuable in some special scenarios to prevent clinical adverse events. This study aimed to develop generic methods for the rapid and simultaneous analysis of four DOACs in human plasma and urine. Protein precipitation and one-step dilution were used to prepare the plasma and urine; the extracts were injected to ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for analysis. Chromatographic separation was performed on an Acquity™ UPLC BEH C₁₈ column (2.1 × 50 mm, 1.7 μm) with gradient elution of 7 min. A triple quadrupole tandem mass spectrometer with an electrospray ionization source was employed to analyze DOACs in a positive ion mode. The methods showed great linearity in the plasma (1~500 ng/mL) and urine (10~10,000 ng/mL) for all analytes (R² ≥ 0.99). The intra- and inter-day precision and accuracy were within acceptance criteria. The matrix effect and extraction recovery were 86.5~97.5% and 93.5~104.7% in the plasma, while 97.0~101.9% and 85.1~99.5% in the urine. The stability of samples during the routine preparation and storage were within the acceptance criteria of less than ±15%. The methods developed were accurate, reliable, and simple for the rapid and simultaneous measurement of four DOACs in human plasma and urine, and successfully applied to patients and subjects with DOACs therapy for anticoagulant activity assessment.

Managing uncertainty: Physicians’ decision-making for stroke prevention for patients with atrial fibrillation and intracerebral haemorrhage

Background Stroke prevention in patients with atrial fibrillation (AF) post-intracerebral haemorrhage (ICH) is an area of clinical equipoise. Little is known about the tools and processes that physicians use to make decisions regarding anticoagulation in this high-risk patient population. Objective To explore physicians’ decision-making process regarding stroke prevention in patients with AF and a recent history of ICH. Method Qualitative study, utilising semi-structured interviews and analysed using Framework analysis. Results Twenty physicians from five European countries (Austria, France, Germany, Spain, United Kingdom) participated. The over-arching theme ‘Managing uncertainty’, addressed the process of making high-risk clinical decisions in the context of little available robust clinical evidence for best practice. Three sub-themes were identified under the umbrella theme: (1) ‘Computing the Risks’, captured the challenge of balancing the risks of ischaemic stroke with the risk of recurrent ICH in a complex patient population; (2) ‘Patient Factors’ highlighted the influence that patients’ beliefs and previous experience of stroke had on physicians’ decisions; and (3) ‘Making a Decision’ explored the process of reaching a final decision regarding initiation of OAC therapy or not. Conclusion Physicians described the process of deciding on stroke prevention in patients with AF post-ICH as ‘challenging’ due to considerable ‘clinical equipoise’. Key factors that affected decision-making was patient comorbidities, functional status, and patient willingness to engage with oral anticoagulation therapy. Shared decision-making was believed to be beneficial, but physicians believed that the ultimate responsibility to decide on stroke prevention lay with the clinician.

Benefits and Risks Associated with Long-term Oral Anticoagulation after Successful Atrial Fibrillation Catheter Ablation: Systematic Review and Meta-analysis

Oral anticoagulation (OAC) prevents thromboembolism yet greatly increases the risk of bleeding, inciting concern among clinicians. Current guidelines lack sufficient evidence supporting long-term OAC following successful atrial fibrillation catheter ablation (CA). A literature search was performed in PubMed, Google Scholar, Medline, and Scopus to seek out studies that compare continued and discontinued anticoagulation in post-ablation Atrial fibrillation (AF) patients. Funnel plots and Egger’s test examined potential bias. Via the random-effects model, summary odds ratios (OR) with 95% confidence intervals (CI) were calculated using RevMan (5.4) and STATA (17.0). Twenty studies, including 22 429 patients (13 505 off-OAC) were analyzed. Stratified CHA₂DS₂-VASc score ≥2 examining thromboembolic events (TE) favored OAC continuation (OR 1.86; 95% CI: 1.02-3.40; P = .04). Sensitivity analysis demonstrated this association was attenuated. The on-OAC arm had greater incidence of major bleeding (MB) (OR 0.16; 95% CI: 0.08-0.95; P < .00001), particularly intracranial hemorrhage (ICH) and gastrointestinal bleeding (GI); (OR 0.17; 95% CI: 0.08-0.36; P < .00001) and (OR 0.12; 95% CI: 0.04-0.32; P < .0001), respectively. Our findings support sustained anticoagulation in patients with a CHA₂DS₂-VASc score of ≥2. Due to reduced outcome robustness, physician discretion is still advised.

Use of Direct Oral Anticoagulant and Outcomes in Patients With Atrial Fibrillation after Transcatheter Aortic Valve Replacement: Insights From the STS/ACC TVT Registry

Background

Clinical evidence on the safety and effectiveness of using direct oral anticoagulants (DOACs) in patients with atrial fibrillation after transcatheter aortic valve replacement (TAVR) remains limited. The aim of this study was to investigate the trends and outcomes of using DOACs in patients with TAVR and atrial fibrillation.

Methods and Results

Data from the STS/ACC TVT (Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy) Registry was used to identify patients who underwent successful TAVR with preexisting or incident atrial fibrillation who were discharged on oral anticoagulation between January 2013 and May 2018. Patients with a mechanical valve, valve‐in‐valve procedure, or prior stroke within a year were excluded. The adjusted primary outcome was 1‐year stroke events. The adjusted secondary outcomes included bleeding, intracranial hemorrhage, and death. A total of 21 131 patients were included in the study (13 004 TAVR patients were discharged on a vitamin K antagonist and 8127 were discharged on DOACs.) The use of DOACs increased 5.5‐fold from 2013 to 2018. The 1‐year incidence of stroke was comparable between DOAC‐treated patients and vitamin K antagonist‐treated patients (2.51% versus 2.37%; hazard ratio [HR], 1.00; 95% CI, 0.81–1.23) whereas DOAC‐treated patients had lower 1‐year incidence of any bleeding (11.9% versus 15.0%; HR, 0.81; 95% CI, 0.75–0.89), intracranial hemorrhage (0.33% versus 0.59%; HR, 0.54; 95% CI, 0.33–0.87), and death (15.8% versus 18.2%; HR, 0.92; 95% CI, 0.85–1.00).

Conclusions

In patients with TAVR and atrial fibrillation, DOAC use, when compared with vitamin K antagonists, was associated with comparable stroke risk and significantly lower risks of bleeding, intracranial hemorrhage, and death at 1 year.

Association between anticoagulants and mortality and functional outcomes in older patients with major trauma

BACKGROUND

The number of trauma patients taking anticoagulants and antiplatelet agents is increasing as society ages. However, there have been limited and inconsistent reports of the association between anticoagulants and mortality and functional outcomes. This study aimed to quantify the association between anticoagulant/antiplatelet medication at the time of injury and both short-term and longer-term outcomes in older major trauma patients.

METHODS

This was a population-based registry study using data from the Victorian State Trauma Registry from July 2017 to June 2018. We included patients with major trauma aged 65 years and older. The outcomes of interest were in-hospital mortality, hospital length of stay, intensive care unit length of stay and the Extended Glasgow Outcome Scale (GOS-E) at 6 months after injury. We examined the association between the outcomes and anticoagulants/antiplatelet agents at the time of injury and used multivariable logistic regression models to account for known confounders.

RESULTS

There were 1323 older adults eligible for inclusion in the study, of which 249 (18.8%) were taking anticoagulants (n=8 were taking both anticoagulants and antiplatelet agents), 380 (28.7%) were taking antiplatelet agents and 694 (52.5%) were not using either. Any anticoagulant use was associated with higher odds of in-hospital mortality (adjusted OR (AOR), 2.38; 95% CI 1.58 to 3.59) compared with not using anticoagulants. No differences were observed in the GOS-E at 6 months after injury between any anticoagulants use, antiplatelet use and no anticoagulant use (anticoagulant AOR, 0.71; 95% CI 0.48 to 1.05, antiplatelet AOR, 1.02; 95% CI 0.73 to 1.42).

CONCLUSION

Anticoagulant use at the time of injury was associated with higher odds of in-hospital mortality but did not adversely impact functional outcomes at 6 months after injury. These findings demonstrate the importance of seeking an accurate history of anticoagulant use and its indication, as well as the immediate initiation of reversal therapies.

Pharmacokinetics of Direct Oral Anticoagulants in Emergency Situations: Results of the Prospective Observational RADOA-Registry

BACKGROUND

Direct oral anticoagulants (DOACs) are increasingly used worldwide. Little is known so far about their pharmacokinetics in emergency situations.

METHODS

A prospective, observational registry was performed to determine the clinical course in consecutive patients with major bleeding or urgent surgery treated with DOACs. In samples collected as part of routine care DOAC drug concentrations were measured using ultraperformance liquid chromatography-tandem mass spectrometry. Anticoagulant intensity at first presentation and drug half-life (t _1/2), tested in repeat samples, were evaluated.

RESULTS

A total of 140 patients were prospectively included. Pharmacokinetic data were available in 94% (132/140) of patients. Note that 67% (89/132) experienced life-threatening bleeding and 33% (43/132) needed an urgent surgery. For pharmacokinetic analysis a total of 605 blood samples was available. Median concentration on admission was 205 ng/mL for rivaroxaban and 108 ng/mL for apixaban. All treatment groups showed a high variation of drug concentrations at baseline. In rivaroxaban-treated patients t _½ was 17.3 hours (95% confidence interval [CI]: 15.4-19.7) without significant difference in both groups (major bleeding: t _½ 16.7 hours, 95% CI: 14.7-19.3; urgent surgery: t _½ 19.7 hours, 95% CI: 15.2-27.9; p = 0.292). In apixaban-treated patients t _½ was 25.0 hours (95% CI: 22.9-27.6) with a longer t _½ after urgent surgery (t _1/2: 30.8 hours; 95% CI: 26.9-36.4) compared with severe bleeding (t _1/2: 20.8 hours; 95% CI: 18.8-23.2; p < 0.001).

CONCLUSION

Emergency patients under DOAC treatment show a high variation of anticoagulant concentrations at baseline. Compared with rivaroxaban, apixaban showed a lower median concentration on admission and a longer t _½.

Edoxaban in Cardiovascular Disease Management: Review

In the past decade, direct oral anticoagulants (DOACs) have transformed the world of anti-thrombotic therapy. Edoxaban is the most recently approved DOAC. Though intended for use primarily in stroke prevention, it has found applications in various other conditions including thromboembolic and peripheral arterial disease. This review aims to provide a detailed outline of the growing indications, evidence for use in special populations, pharmacogenetics, and side effect profile of edoxaban.

Direct Oral Anticoagulants Plasma Levels in Patients with Atrial Fibrillation at the Time of Bleeding: A Pilot Prospective Study

ABSTRACT

Patients with atrial fibrillation (AF) on long-term direct oral anticoagulants (DOACs) may be at higher risk of bleeding because of higher anti-Xa or anti-IIa levels. However, there is no postmarketing study investigating these DOAC plasma levels at the time of bleeding. The aim of this study was to evaluate DOAC levels at the time of a bleeding emergency. We analyzed 5440 patients examined at our Emergency Department in from April 1, 2019, to September 30, 2019. During this period, we prospective identified 105 consecutive patients with bleeding while on long-term antithrombotic therapy; 49 patients had AF on DOACs. We compared DOAC levels in patients who bled against a control sample of 55 patients who tolerated long-term high dose DOAC therapy without any emergency. Samples of these patients were tested with drug-specific anti-Xa chromogenic analysis (rivaroxaban and apixaban) and with Hemoclot Thrombin Inhibitor assay (dabigatran). Dabigatran-treated patients who bled had significantly higher anti-IIa levels when compared with trough (261.4 ± 163.7 vs. 85.4 ± 57.2 ng/mL, P < 0.001) and peak samples of controls (261.4 ± 163.7 vs. 138.8 ± 78.7 ng/mL, P < 0.05). Similarly, there were significantly higher anti-Xa levels in rivaroxaban-treated and apixaban-treated patients with bleeding compared with trough control samples (rivaroxaban: 245.9 ± 150.2 vs. 52.5 ± 36.4 ng/mL, P <0.001 and apixaban: 311.8 ± 142.5 vs. 119.9 ± 81.7 ng/mL, P < 0.001), as well as in apixaban-treated patients when compared with peak control samples (311.8 ± 142.5 vs. 210.9 ± 88.7 ng/mL, P < 0.05). Finally, rivaroxaban anti-Xa levels in patients who bled tended to be higher compared with peak control samples (245.9 ± 150.2 vs. 177.6 ± 38.6 ng/mL, P = 0.13). This observational study showed a significant difference in anti-IIa and anti-Xa plasma levels in patients with AF with bleeding complications compared with those who tolerated long-term high-dose DOAC therapy without bleeding complications.

Measuring residual anti-Xa activity of direct factor Xa inhibitors after reversal with andexanet alfa

Introduction

Andexanet alfa (AnXa) was developed for anticoagulant effect reversal of direct factor Xa inhibitors (DXaI) (apixaban, rivaroxaban, edoxaban) in emergency situations. Regular anti‐Xa assays are not suitable to evaluate anti‐Xa activity after AnXa administration because of the high sample dilution resulting in the AnXa‐DXaI dissociation which gives inaccurately high DXaI measured concentrations. This study aimed at developing dedicated STA‐Liquid anti‐Xa test set‐ups for accurately measuring DXaI after reversal with AnXa.

Methods

Modified anti‐Xa test set‐ups, with reduced sample dilution, were developed to overcome regular assays limitations and to improve measured accuracy with results comparable to Portola microplate reference method used in clinical studies. Both regular and optimized assays were used to measure DXaI concentration in AnXa‐containing samples. Quality controls, normal pooled plasma spiked with five DXaI and three AnXa concentrations, samples from DXaI‐treated patients spiked with AnXa and ex vivo healthy volunteers having received both DXaI and AnXa were used.

Results

The lower limit of quantitation of optimized anti‐Xa assays was <10 ng/mL with CVs ≤10%. DXaI samples containing 300 ng/mL and 1 µmol/L AnXa resulted in DXaI residual concentrations of 29‐72 ng/mL depending on the DXaI (76%‐90% reversal), compared to 20‐28 ng/mL with reference method (92%‐94% reversal) and 135‐165 ng/mL with regular assays (about 50% reversal).

Conclusion

Modified test set‐ups are automated alternative to reference method with improved precision and reproducibility. They can be run in all laboratories where regular anti‐Xa assays are performed using commercially available reagents.

Mandibular Fracture in a Patient Taking a Direct Oral Anticoagulant

ABSTRACT

A 74-year-old man presented with hemorrhage from the mandible after an injury caused by a 5 × 3 × 3-cm metal square column flying from a 45-ton press machine that struck the right side of his face. He is a known atrial fibrillation patient and is on rivaroxaban, a direct oral anticoagulant. An approximately 8-cm Y-shaped wound with persistent hemorrhage was observed in the right mandible, and the mandible was displaced between the right mandibular canine and first premolar. Although the patient showed no dyspnea, the sublingual region showed a slight dark purple swelling; fiberoptic nasal intubation was performed. Computed tomography at 3.5 hours after the injury revealed a comminuted fracture of the right mandibular body, edema at the floor of the mouth, nasal cavity, upper pharynx to hypopharynx, and the pharyngeal airway around the endotracheal tube. Open reduction and internal fixation were performed. Rivaroxaban was started again 3 days after surgery.

Translational PK/PD and model-informed development of JNJ-67842125, a Fab reversal agent for JNJ-64179375, a long-acting thrombin inhibitor

BACKGROUND AND PURPOSE

Antigen-binding fragment (F_ab ) reversal agents were developed to reverse, in bleeding emergency, the long-acting anticoagulant effect of JNJ-64179375 (JNJ-9375), a monoclonal antibody that binds exosite-1 on thrombin.

EXPERIMENTAL APPROACH

The pharmacokinetic and pharmacodynamic (PK/PD) activities of three reversal agents of varying in vitro binding affinities to JNJ-9375 were characterised in cynomolgus monkeys. The time course of JNJ-9375 anticoagulant activity and reversal effects of each agent were evaluated. A mechanism-based PK/PD model, which integrated free serum concentrations of reversal agent, total and free serum concentrations of JNJ-9375, and thrombin time, was developed to quantitatively relate JNJ-9375 neutralisation to reversal of induced thrombin time prolongation. Model-based allometric scale-up of the lead reversal agent and the PK/PD relationship of JNJ-9375 in healthy volunteers were utilised to predict clinical dosing regimens.

KEY RESULTS

Lowering of free JNJ-9375 by the reversal agents corresponded with reversal of thrombin time prolongation. Total JNJ-9375 displayed typical mAb clearance at 2.75 ml·day^-1 ·kg^-1 , whereas reversal agents cleared faster between 1400 and 2400 ml·day^-1 ·kg^-1 . The model-estimated in vivo K_D values for JNJ-9375 reversal agents were 9 nM (ICHB-256), 0.4 nM (ICHB-281) and 13.7 pM (ICHB-164), in rank-ordered agreement of their K_D values determined in vitro. The three reversal agents exhibited different neutralisation characteristics in vivo, governed primarily by their binding kinetics to JNJ-9375. The model predicted a priori free JNJ-9375 kinetics after dosing ICHB-164 (JNJ-67842125) and JNJ-9375 under a different regimen.

CONCLUSION AND IMPLICATIONS

The results enabled selection of JNJ-67842125 as the reversal agent for JNJ-9375.

Meta-analysis of direct oral anticoagulants compared with vitamin K antagonist for left ventricle thrombus

BACKGROUND

The use of direct oral anticoagulants (DOAC) in preference to vitamin K antagonists (VKA) as a treatment of left ventricle (LV) thrombus is controversial.

METHODS

Literature search for full-text articles and conference abstracts was performed using PubMed, EMBASE databases search was performed to identify articles that compared use of DOAC vs. VKA in patients with LV thrombus. The primary outcome was composite failure or adverse effects of DOAC and VKA. Other outcomes were resolution of thrombus, systemic thromboembolism, major bleeding, and mortality. Pooled odds ratio (OR) with 95% confidence interval (CI) were computed using random effects model.

RESULTS

Seven studies with 1003 patients (mean age DOAC = 58.8 years and VKA = 58.9 year, 55.5% males) were included in this study. There were 306 (30.5%) patients that were treated with DOAC and 697 (69.5%) patients were treated with VKA. Overall, there were no significant differences between both agents in terms of composite failure/adverse effects, resolution of thrombus, systemic embolism, major bleeding, or mortality.

CONCLUSION

In this pooled analysis, outcomes in patients on DOAC were comparable to VKA. The hypothesis generated could suggest DOAC could be used interchangeably with VKA in patients with LV thrombus. Randomized trials are needed for generalization of results.

Real-life data of major and minor bleeding events with direct oral anticoagulants in the one-year follow-up period: The NOAC-TURK study

OBJECTIVE

This study aimed to evaluate the safety of direct oral anticoagulants (DOACs) in patients with non-valvular atrial fibrillation (NVAF) during daily clinical practice.

METHODS

This was a prospective study conducted between January 01, 2016, and April 01, 2017, in patients aged ≥18 years with a diagnosis of NVAF. We performed the study in 9 clinical centers from different regions of Turkey, and the mean follow-up period was 12+2 months. We investigated major and minor bleeding events of DOAC.

RESULTS

A total of 1807 patients with NVAF were enrolled. The mean age of the patients was 73.6±10.2 years, CHA2DS2-VASc score was 3.6±1.4, and HAS-BLED score was 2±1.2. The most frequently prescribed DOAC was dabigatran 110 mg bid in 409 (22.6%) patients. The patients on apixaban 2.5 mg bid were older (p<0.001). Patients on rivaroxaban 15 mg od also had a higher prevalence of chronic renal failure, 46 (16.7%) patients. A total of 205 (11.4%) bleeding events were observed; among these, 34 (1.9%) patients had major bleeding and 171 (9.4%) patients had minor bleeding. The major and minor bleeding events were 2/273 (0.7%) and 30/273 (10.9%) in patients receiving dabigatran 150 mg bid, 13/409 (3%) and 44/409 (10.7%) in patients receiving dabigatran 110 mg bid, 4/385 (1%) and 42/385 (10.9%) in patients receiving rivaroxaban 20 mg od, 8/276 (2.9%) and 27/276 (9.7%) in patients receiving rivaroxaban 15 mg od, 3/308 (0.9%) and 14/308 (4.5%) in patients receiving apixaban 5 mg bid, 4/156 (2.5%) and 14/156 (9%) in patients receiving apixaban 2.5 mg bid, respectively. The total bleeding events were 17 (5.6%) in patients receiving apixaban 5 mg, less than those receiving other DOACs. On multivariate analyses, rivaroxaban 20 mg od (p=0.002), ATRIA and HAS-BLED scores, and peripheral artery disease were independent indicators of bleeding. The most frequent location of major bleeding was the gastrointestinal system (GIS) [17 (0.9%) patients], and the most frequent location of minor bleeding was the gingiva [45 (2.5%) patients].

CONCLUSION

This study showed that similar results as the previous real-life study; however, we had some different results, such as the GIS tract bleeding was more frequent in patients receiving dabigatran 110 mg bid. The major and intracranial bleeding events were similar for different DOACs; and among DOACs, only rivaroxaban 20 mg od was associated with a high risk of bleeding.

Real-World Data on Characteristics and Management of Community Patients Receiving Anticoagulation Therapy Who Presented with Acute Bleeding to the Emergency Department at a Regional Australian Hospital: A Prospective Observational Study

OBJECTIVE

To study patients receiving anticoagulants with or without antiplatelet therapy presenting at a regional Australian hospital with bleeding. The main aims are to explore: (1) patients' characteristics and management provided; (2) association between the type of anticoagulant and antiplatelet agent used and the requirement of reversal; (3) and the length of hospital stay (LoS) in conjunction with bleeding episode and management.

METHODS

A prospective cross-sectional review of medical records of all patients who presented at a tertiary referral centre with bleeding while receiving anticoagulation therapy between January 2016 and June 2018. Data included: patients, demographics, investigations (kidney and liver function tests, coagulation profile, FBC), LoS, bleeding site, type of and reason for anticoagulation therapy, and management provided. Data analysis included descriptive statistics, χ2 association, and regression models.

RESULTS

Among the 144 eligible patients, 75 (52.1%) were male, and the mean age was 76 years (SD=11.1). Gastrointestinal tract bleeding was the most common (n=48, 33.3%), followed by epistaxis (n=32, 22.2%). Atrial fibrillation was the commonest reason for anticoagulation therapy (n=65, 45.1%). Warfarin was commonly used (n=74, 51.4%), followed by aspirin (n=29, 20.1%), rivaroxaban (n=26, 18.1%), and apixaban (n=12, 8.3%). The majority had increased blood urea nitrogen (n=67, 46.5%), while 58 (40.3%) had an elevated serum creatinine level, and 59 (41.0%) had a mild reduction in eGFR. Thirty-five of the warfarinised patients (47.3%) had an INR above their condition's target range despite normal liver function. Severe anaemia (Hb<80g/L) was reported in 88 patients (61.1%). DOACs were associated with a reduced likelihood of receiving reversal (B= -1.7, P=<.001), and with a shorter LoS (B= -4.1, P=.046) when compared with warfarin, LMWH, and antiplatelet therapy.

CONCLUSION

Warfarin use was common among patients who presented with acute bleeding, and the INR in many warfarinised patients exceeded the target for their condition. DOACs were associated with a reduced likelihood of receiving reversal and a shorter LoS than warfarin, LMWH, which might support a broader application of DOACs into community practice.

Four-factor Prothrombin Complex Concentrate for Reversal of Factor Xa Inhibitors versus Warfarin in Life-threatening Bleeding

INTRODUCTION

Factor Xa (fXa) inhibitor reversal for life-threatening bleeding is controversial due to a lack of high-quality evidence. The purpose of this study was to determine the hemostatic efficacy of four-factor prothrombin complex concentrate (4F-PCC) for the reversal of fXa inhibitors compared to warfarin for life-threatening bleeding.

METHODS

This was a multicenter, retrospective cohort study at two academic medical centers between January 1, 2014-December 31, 2019, which included patients who presented to the emergency department with a life-threatening bleed necessitating anticoagulation reversal with 4F-PCC. The primary endpoint was achievement of hemostatic efficacy after 4F-PCC administration.

RESULTS

Of the 525 patients who had an order for 4F-PCC during the study period, 148 patients met the criteria for inclusion (n = 48 fXa inhibitor group; n = 100 warfarin group). Apixaban (52.1%) and rivaroxaban (45.8%) were the most commonly used fXa inhibitors. Effective hemostasis was similar between groups (79.2% fXa inhibitor group vs 85% warfarin group, p = 0.38). This was consistent across all types of bleeding. Thrombotic events were rare in both groups (2% vs 3%).

CONCLUSION

This multicenter, retrospective cohort study demonstrated that using 4F-PCC for treatment of life-threatening bleeding produced effective hemostasis in patients on fXa inhibitors and warfarin.

Atrial Fibrillation and Stroke

Atrial fibrillation (AF) is the most common cardiac arrythmia and a major cause of stroke, heart failure, sudden death, and cardiovascular morbidity. AF increases risk of thromboembolic stroke via stasis in the left atrium and subsequent embolization to the brain. In patients with acute ischemic stroke, it is essential that clinicians undertake careful investigation to search for AF. In these patients, up to 23.7% eventually are found to have underlying AF. Oral anticoagulation is effective in prevention of strokes secondary to AF, reducing overall stroke numbers by approximately 64%. Left atrial appendage occlusion is promising for prevention of stroke in AF.

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.

The relationship between DOAC levels and clinical outcomes: The measures tell the tale

Direct oral anticoagulants (DOACs) are increasingly used for treatment and prevention of thromboembolic diseases, used in fixed dose regimens. Although their safety and efficacy profiles are considered optimal, clinical events still occur. Given that anticoagulation treatment is a delicate balance between clotting and bleeding, it is possible that an optimal target spot exists where the effect of anticoagulation achieves both the lowest possible risk of bleeding and thrombosis. Other currently available anticoagulants (ie, vitamin K antagonists and heparins) provide important clues for this. If such a target spot exists, tailored DOAC therapy may further benefit patients. This opinion article summarizes the current available evidence that suggests that such a tailored strategy could work. It also describes research suggestions for conducting studies in patient populations such as patients with extremes of body weight or impaired kidney function to evaluate whether tailored treatment with DOACs could lead to better patient outcomes.

Elderly people are inherently sensitive to the pharmacological activity of rivaroxaban: implications for DOAC prescribing

According to both trial and clinical data on direct oral anticoagulants (DOACs) elderly patients are at greatest risk of bleeding. It is unclear whether age intrinsically affects anticoagulation response. To investigate the age-related sensitivity to DOACs, we compared the pharmacological activity of the direct factor Xa inhibitor, rivaroxaban, between young and elderly subjects ex-vivo. 36 fit elderly and 30 fit young subjects [median (IQR) age: 83(75–87) vs 30(26–38) years] provided a blood sample. Clotting parameters were measured in the resultant plasma samples incubated with rivaroxaban (100–500 ng/ml). Parametric, non-parametric tests and regression lines adjusted for rivaroxaban concentration and baseline values were used to compare data. Rivaroxaban produced a greater prolongation of both Prothrombin Time (PT) and modified Prothrombin Time (mPT) (both p < 0.001) in the elderly compared to young subjects (with difference in mean PT increasing from 1.6 to 6.1s and for mPT from 23.5 to 71.1s at 100 ng/ml and 500 ng/ml plasma rivaroxaban concentration, respectively). Factor X and factor II activity was significantly lower in the elderly in the presence of rivaroxaban (p < 0.001 for both). Rivaroxaban prolonged time-based parameters and suppressed the amount of thrombin generation to a significantly greater extent in the elderly compared to young subjects [%change from baseline for Endogenous Thrombin Potential (ETP): − 35.0 ± 4.4 vs − 29.8 ± 7.4 nM*min; p = 0.002]. The use of validated DOAC assays will be of considerable benefit for monitoring elderly patients who, because of their increased sensitivity to rivaroxaban, may require lower doses of the drug for therapeutic anticoagulation.

Extended DOAC therapy in patients with VTE and potential risk of recurrence: A systematic review and meta-analysis

BACKGROUND

Guidelines recommend at least 3 months of anticoagulation for venous thromboembolism (VTE). Evidence supporting indefinite anticoagulation exists in certain conditions; however, for many patients, uncertainty regarding when to discontinue anticoagulation persists.

OBJECTIVE

We aimed to investigate the efficacy and safety of extended direct oral anticoagulants (DOAC) therapy in patients with VTE and clinical uncertainty regarding extended anticoagulation.

METHODS

We searched EMBASE, MEDLINE, PubMed, and Cochrane Central Register of Controlled Trials databases for randomized control trials examining extended anticoagulation with DOACs as compared to non-extended therapy for the treatment of VTE.

RESULTS

Of 560 citations identified by the search, three studies were eligible. Extended anticoagulation reduced VTE recurrence (relative risk [RR] 0.18, 95% confidence interval [CI] 0.12 to 0.25), and mortality (RR 0.39, 95% CI 0.19 to 0.80) with a low total number of deaths in the DOAC group (n = 12) versus placebo (n = 18). Extended anticoagulation increased clinically relevant non-major bleedings (RR 2.51, 95% CI 1.37 to 4.59). There was no difference in rates of major bleeding (RR 1.87, 95% CI 0.19 to 17.85); however, there was a low number of major bleeding events in both DOAC (n = 9) and placebo groups (n = 4). The results were mostly driven by one study (AMPLIFY-EXT), with significant heterogeneity between studies noticed when assessing bleeding outcomes.

CONCLUSION

Extended DOAC therapy for 1 year in patients with clinical uncertainty for ongoing anticoagulation can reduce VTE recurrence and mortality; however, it could increase clinically relevant non-major bleeding events.

Clinics in diagnostic imaging (201). Small bowel intramural haematoma induced by anticoagulation therapy with associated reactive ileus

A 74-year-old woman receiving long-term anticoagulation with warfarin for chronic atrial fibrillation presented with severe acute abdominal pain, diarrhoea and vomiting. Initial laboratory workup revealed a deranged coagulation profile. Computed tomography of the abdomen and pelvis demonstrated spontaneous distal jejunal intramural haematoma with associated reactive ileus. No overt pneumatosis intestinalis, intraperitoneal free gas or haemoperitoneum was seen. Based on clinical and imaging findings, a diagnosis of over-anticoagulation complicated by small bowel intramural haematoma was made. The patient was managed non-operatively with analgesia, cessation of warfarin and reversal therapy with vitamin K. Warfarin therapy was recommenced upon resolution of symptoms and optimisation of coagulation status. The clinical presentation, radiological features and overall management of anticoagulation-induced bleeding are further discussed in this article.

European Stroke Organisation Guideline on Reversal of Oral Anticoagulants in Acute Intracerebral Haemorrhage

The aim of the present European Stroke Organisation guideline document is to provide clinically useful evidence-based recommendation on reversal of anticoagulant activity VKA (warfarin, phenprocoumon and acenocoumarol), direct factor II (thrombin) inhibitors (dabigatran etexilat) and factor-Xa-inhibitors (apixaban, edoxaban and rivaroxaban) in patients with acute intracerebral haemorrhage. The guideline was prepared following the Standard Operational Procedure for a European Stroke Organisation guideline document and according to GRADE methodology. As a basic principle, we defined use of oral anticoagulation pragmatically: oral anticoagulation use is assumed by positive medical history unless relevant anticoagulant activity is regarded unlikely by medical history or has been ruled out by laboratory testing. Overall, we strongly recommend using prothrombin complex over no treatment and fresh-frozen plasma in patients on VKA plus vitamin K. We further strongly recommend using idarucizumab in patients on dabigatran and make a recommendation for andexanet alfa in patients on rivaroxaban and apixaban over no treatment. We make a weak recommendation on using high-dose prothrombin complex concentrate (50 IU/kg) for all patients taking edoxaban and for patients on rivaroxaban or apixaban in case andexanet alfa is not available. We recommend against using tranexamic acid and rFVIIa, outside of trials. The presented treatment recommendations aim to normalise coagulation, there is no or only indirect data on effects on functional outcome or mortality, and only little data from randomised controlled trials.

Management of anticoagulation in patients with metastatic castration-resistant prostate cancer receiving abiraterone + prednisone

PURPOSE

Abiraterone has been proven to be an effective agent used in the management of metastatic castration-resistant prostate cancer, significantly improving overall and progression-free survival. Due to the pharmacodynamic and pharmacokinetic properties of abiraterone, concurrent use with anticoagulation may pose a challenge for clinicians. Thrombosis within the cancer setting continues to increase patient mortality; therefore, appropriate anticoagulation through the use of a management algorithm can reduce adverse events and increase quality of life.

METHODS

A review of the literature was preformed by a medical oncologist, haematologist and pharmacists to identify relevant randomized controlled trials, meta-analyses and retrospective studies. Major society guidelines were reviewed to further aid in developing the anticoagulation protocol for non-valvular atrial fibrillation and venous thromboembolism within this patient population. After reviewing the literature, a clinical framework was designed to aid clinicians in the management of those patients receiving abiraterone concurrently with an anticoagulant.

RESULTS

In this review, we describe the potential interactions between abiraterone and various anticoagulants and provide management strategies based on the most recent literature for atrial fibrillation, venous thromboembolism and mechanical heart valves to avoid potential drug-drug interactions.

CONCLUSION

Abiraterone therapy has become a mainstay of the management of advanced prostate cancer and is often used over prolonged years. In this review, we have summarized a framework of how to use abiraterone in men with prostate cancer on anticoagulants. Evidence available to date suggests that patients with an indication for anticoagulation such as atrial fibrillation, venous thromboembolism and mechanical heart valves can be treated safely with abiraterone in the appropriate setting, with appropriate monitoring.

Preventable Cases of Oral Anticoagulant-Induced Bleeding: Data From the Spontaneous Reporting System

Background

Despite the risk of bleeding is a well-known adverse effect of oral anticoagulants, there is scarce evidence on the preventability of oral anticoagulant-induced bleedings. Therefore, we investigated the potential risk factors related to preventable cases of oral anticoagulant-induced bleedings.

Methods

We performed a study using Individual Case Safety Reports (ICSRs) with an oral anticoagulant as suspected drug among those reported through the spontaneous reporting system of Campania Region from 1 July 2012 to 31 December 2017. The P-method was used for the preventability assessment of all cases of bleeding.

Results

In total, 58 cases out of 253 (22.9%) were preventable, and the most reported suspected drug was an indirect oral anticoagulant (warfarin). Sixty-eight critical criteria for preventability were identified, all related to healthcare professionals' practices. The most detected risk factor related to healthcare professionals' practices was the labeled drug-drug interaction for both direct and indirect oral anticoagulants.

Conclusion

Our findings describe the most reported risk factors for preventability of oral anticoagulant-induced bleedings. These factors may be useful for targeting interventions to improve pharmacovigilance activities in our regional territory and to reduce the burden of medication errors and inappropriate prescription.

Specific Antidotes for Direct Oral Anticoagulants in Life-Threatening Bleeding

Review presents data on medicines from the new group of cardiovascular drugs, direct oral anticoagulants (DOACs) inhibitors, as antidotes for DOAC when stopping life-threatening bleeding. DOAC therapy is accorded by hemorrhages with lower frequency than therapy by indirect anticoagulants, but really exist. New antidotes for DOACs are idarucizumab, andexanet, ciraparantag. The need in antidotes for DOAC may suddenly appear in spontaneous bleeding, during surgical operation, invasive procedure, due to trauma, in patients with stroke, kidney or liver failure. Data is given on the frequency of the main types of bleeding while taking new oral anticoagulants. Information concerning use of antidotes for DOACs in bleedings as well as use of non-specific therapy are reviewed.

 

The impact of prothrombin complex concentrates when treating DOAC-associated bleeding: a review

Background

Bleeding complications are a risk associated with all anticoagulants. Currently, the treatment options for the management of direct oral anticoagulant (DOAC)-associated bleeding are limited. Prothrombin complex concentrates (PCCs) have been proposed as a potential therapeutic option, and evidence regarding their use is increasing.

Review

Many studies supporting PCC have used preclinical models and healthy volunteers; however, more recently, observational studies have further improved insight into current DOAC reversal strategies. Multiple clinical practice guidelines now specifically suggest use of PCCs for this indication. Specific reversal agents for Factor Xa inhibitors may become available in the near future, but data on their efficacy are still emerging.

Conclusions

Ultimately, a multimodal approach may be the optimal strategy to restore haemostasis in patients presenting with DOAC-associated coagulopathy.

Electronic supplementary material

The online version of this article (10.1186/s12245-018-0215-6) contains supplementary material, which is available to authorized users.

Effect of low and moderate dose FEIBA to reverse major bleeding in patients on direct oral anticoagulants

OBJECTIVE

Management of acute, major or life threatening bleeding in the presence of direct acting oral anticoagulants (DOAC) is unclear. In the absence of a specific antidote, or in situations where there is a need for adjunctive therapy, the ideal prothrombin complex concentrate and dose is unclear. The goal of our study was to evaluate the outcomes of our reduced dosing strategy with FEIBA in patients experiencing a DOAC-related bleeding event.

DESIGN

Retrospective analysis of patients treated with FEIBA for a DOAC-related bleeding event.

SETTING

Academic medical center PATIENTS: Consecutive patients between May 2011 and April 2017 receiving FEIBA for a DOAC-related bleed INTERVENTIONS: None MEASUREMENTS & MAIN RESULTS: Of the 64 patients included in this analysis, 38 patients received low dose FEIBA (mean 10.0 ± 3.6 units/kg) and 26 received moderate dose (mean 24.3 ± 2.1 units/kg) FEIBA; an additional dose was requested in 6 patients. Six dabigatran patients received idarucizumab. 30 day event rates included 5 thromboembolic events (8%) and 9 (14%) patients expired. Follow-up CT-imaging for ICH, endoscopy/colonoscopy, or interventional radiology exams did not reveal any clinically concerning active bleeding or hematoma expansion except in 2 ICH patients with slight expansion between imaging sessions.

CONCLUSIONS

Low (<20 units/kg) to moderate (20-30 units/kg) doses of FEIBA, with the option for a repeat dose, may be an effective management strategy for obtaining hemostasis in DOAC-related major bleeding events.

External Validation of Hematoma Expansion Scores in Spontaneous Intracerebral Hemorrhage in an Asian Patient Cohort

BACKGROUND

Hematoma expansion (HE) occurs in approximately one-third of patients with intracerebral hemorrhage (ICH) and is known to be a strong predictor of neurological deterioration as well as poor functional outcome. This study aims to externally validate three risk prediction models of HE (PREDICT, 9-point, and BRAIN scores) in an Asian population.

METHODS

A prospective cohort of 123 spontaneous ICH patients admitted to a tertiary hospital (certified stroke center) in Singapore was recruited. Logistic recalibrations were performed to obtain updated calibration slopes and intercepts for all models. The discrimination (c-statistic), calibration (Hosmer-Lemeshow test, le Cessie-van Houwelingen-Copas-Hosmer test, Akaike information criterion), overall performance (Brier score, R²), and clinical usefulness (decision curve analysis) of the risk prediction models were examined.

RESULTS

Overall, the recalibrated PREDICT performed best among the three models in our study cohort based on the novel matrix comprising of Akaike information criterion and c-statistic. The PREDICT model had the highest R² (0.26) and lowest Brier score (0.14). Decision curve analyses showed that recalibrated PREDICT was more clinically useful than 9-point and BRAIN models over the greatest range of threshold probabilities. The two scores (PREDICT and 9-point) which incorporated computed tomography (CT) angiography spot sign outperformed the one without (BRAIN).

CONCLUSIONS

To our knowledge, this is the first study to validate HE scores, namely PREDICT, 9-Point and BRAIN, in a multi-ethnic Asian ICH patient population. The PREDICT score was the best performing model in our study cohort, based on the performance metrics employed in this study. Our findings also showed support for CT angiography spot sign as a predictor of outcome after ICH. Although the models assessed are sufficient for risk stratification, the discrimination and calibration are at best moderate and could be improved.

Non-Vitamin K Oral Anticoagulants Associated Bleeding and Its Antidotes

Oral anticoagulant-associated intracerebral hemorrhage (OAC-ICH) accounts for nearly 20% of all ICH. The number of patients with an indication for oral anticoagulant therapy (OAT) increases with increasing age. OAT became less complicate with the introduction of non-vitamin K oral anticoagulants (NOAC) OAT because of easier handling, favorable risk-benefit profile, reduced rates of ICH compared to vitamin K antagonists and no need for routine coagulation testing. Consequently, despite a better safety profile of NOAC the number of patients with OAC-ICH will increase. The mortality and complication rates of OAC-ICH are high and therefore they are the most feared complication of OAT. Immediate normalization of coagulation is the main goal and therefore knowledge of pharmacodynamics and coagulation status is essential. Laboratory measurements of anticoagulant activity in NOAC patients is challenging as specific tests are not widely available. More accessible tests such as the prothrombin time and activated partial thromboplastin time have important limitations. In dabigatran-associated ICH 5 g Idarucizumab should be administered. In rivaroxaban and apixaban-associated ICHs administration of andexanet alpha should be considered. Prothrombin complex concentrate may be considered if andexanet alpha is not available or in case of an ICH associated with edoxaban.

Optimizing medical management in peripheral artery disease

Changing times

Management of Elective Surgery and Emergent Bleeding with Direct Oral Anticoagulants

PURPOSE OF REVIEW

The purpose of this review was to offer practical management strategies for when patients receiving direct oral anticoagulants require elective surgery or present with bleeding complications.

RECENT FINDINGS

Clinical practice guidelines are now available on the timing of periprocedural interruption of treatment with the newer direct oral anticoagulants based on their pharmacodynamics and pharmacokinetics and based on findings from cohort studies and clinical trials. An antibody that reverses the effects of dabigatran is now available, and a factor Xa decoy is being developed as an antidote to apixaban, betrixaban, edoxaban, and rivaroxaban. The timing of interruption of direct oral anticoagulants for elective surgery is based on multiple factors, including pharmacologic properties and interactions, the patient's renal function, and the type of planned surgery. There is little role for low-molecular-weight heparin bridging. Idarucizumab is the treatment of choice for dabigatran-related life-threatening bleeding, while andexanet alfa is being developed to reverse factor Xa inhibitors.

Dosing-time-dependent effect of rivaroxaban on coagulation activity in rats

The anticoagulant effect of rivaroxaban, a direct inhibitor of activated factor X (FX), might be influenced by its dosing time because the activity of the coagulofibrinolytic system exhibits daily rhythmicity. In rats, FX activity follows a 24-h rhythm with a peak in the middle of the light phase and a trough at the beginning of the dark phase. Consistent with these findings, a single dose of rivaroxaban had a stronger inhibitory effect on FX activity after dosing at the beginning of the light phase than after dosing at the beginning of the dark phase. A similar chronopharmacological effect was seen in a quantitative model of venous stasis thrombosis. In comparison, the dosing time had minimal influence on the pharmacokinetics of rivaroxaban. These data indicate that the anticoagulant effect of rivaroxaban is influenced by the dosing time. Further studies should confirm this finding in a clinical setting.