Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation

Dependence of clot structure and fibrinolysis on apixaban and clotting activator

Background

Anticoagulants prevent the formation of potentially fatal blood clots. Apixaban is a direct oral anticoagulant that inhibits factor (F)Xa, thereby impeding the conversion of prothrombin into thrombin and the formation of blood clots. Blood clots are held together by fibrin networks that must be broken down (fibrinolysis) to restore blood flow. Fibrinolysis is initiated when tissue plasminogen activator (tPA) converts plasminogen to plasmin, which binds to and degrades a fibrin fiber. The effects of apixaban on clot structure and lysis have been incompletely studied.

Objectives

We aimed to study apixaban effects on clot structure, kinetics, and fibrinolysis using thrombin (low or high concentration) or tissue factor (TF) to activate clot formation.

Methods

We used a combination of confocal and scanning electron microscopy and turbidity to analyze the structure, formation kinetics, and susceptibility to lysis when plasma was activated with low concentrations of thrombin, high concentrations of thrombin, or TF in the presence or absence of apixaban.

Results

We found that the clotting activator and apixaban differentially modulated clot structure and lytic potential. Low thrombin clots with apixaban lysed quickly due to a loose network and FXa cleavage product's cofactor with tPA; high thrombin clots lysed faster due to FXa cleavage product's cofactor with tPA; TF generated loose clots with restricted lysis due to their activation of thrombin activatable fibrinolytic inhibitor.

Conclusion

Our study elucidates the role of apixaban in fibrinolytic pathways with different clotting activators and can be used for the development of therapeutic strategies using apixaban as a cofactor in fibrinolytic pathways.

Intracerebral haemorrhage in patients taking different types of oral anticoagulants: a pooled individual patient data analysis from two national stroke registries

BACKGROUND

We investigated outcomes in patients with intracerebral haemorrhage (ICH) according to prior anticoagulation treatment with Vitamin K antagonists (VKAs), direct oral anticoagulants (DOACs) or no anticoagulation.

METHODS

This is an individual patient data study combining two prospective national stroke registries from Switzerland and Norway (2013-2019). We included all consecutive patients with ICH from both registries. The main outcomes were favourable functional outcome (modified Rankin Scale 0-2) and mortality at 3 months.

RESULTS

Among 11 349 patients with ICH (mean age 73.6 years; 47.6% women), 1491 (13.1%) were taking VKAs and 1205 (10.6%) DOACs (95.2% factor Xa inhibitors). The median percentage of patients on prior anticoagulation was 23.7 (IQR 22.6-25.1) with VKAs decreasing (from 18.3% to 7.6%) and DOACs increasing (from 3.0% to 18.0%) over time. Prior VKA therapy (n=209 (22.3%); adjusted ORs (aOR), 0.64; 95% CI, 0.49 to 0.84) and prior DOAC therapy (n=184 (25.7%); aOR, 0.64; 95% CI, 0.47 to 0.87) were independently associated with lower odds of favourable outcome compared with patients without anticoagulation (n=2037 (38.8%)). Prior VKA therapy (n=720 (49.4%); aOR, 1.71; 95% CI, 1.41 to 2.08) and prior DOAC therapy (n=460 (39.7%); aOR, 1.28; 95% CI, 1.02 to 1.60) were independently associated with higher odds of mortality compared with patients without anticoagulation (n=2512 (30.2%)).

CONCLUSIONS

The spectrum of anticoagulation-associated ICH changed over time. Compared with patients without prior anticoagulation, prior VKA treatment and prior DOAC treatment were independently associated with lower odds of favourable outcome and higher odds of mortality at 3 months. Specific reversal agents unavailable during the study period might improve outcomes of DOAC-associated ICH in the future.

[What is confirmed in the treatment of ischemic stroke]

Ischemic stroke is one of the leading causes of death worldwide and the most frequent cause of permanent disability in adulthood. The acute treatment of stroke is time-critical and, according to the time is brain principle, it is important to determine as soon as possible whether recanalization treatment that can save the penumbra is possible. Intravenous thrombolysis (IVT) and, if a large vessel occlusion is identified, endovascular treatment (EVT) possibly in combination with IVT, are recommended. Further treatment in a stroke unit is another important component of acute stroke treatment. The best secondary preventive treatment must already be initiated in the acute phase. The cause of stroke guides making decisions on the ideal secondary preventive strategy. The most important etiologies of stroke are cardiac embolism, atherosclerotic macroangiopathy and cerebral microangiopathy (small vessel disease). Less frequent causes are dissections of arteries supplying the brain or vasculitis. In up to 20-30% of all cases, however, no clear etiology can be determined despite intensive investigation of the cause. This means corresponding uncertainty in the optimal secondary prevention that consists in particular of an anticoagulant medication adapted to the etiology, treatment of cardiovascular risk factors and if necessary surgical or interventional desobliterative procedures. This article describes the diagnostic procedure and the evidence-based treatment of ischemic stroke.

A Real-World Evaluation of Primary Medication Nonadherence in Patients with Nonvalvular Atrial Fibrillation Prescribed Oral Anticoagulants in the United States

BACKGROUND

Nonadherence to oral anticoagulants (OACs) is a challenge to stroke risk reduction in patients with nonvalvular atrial fibrillation (NVAF). Data on primary medication nonadherence (PMN) in NVAF are lacking.

OBJECTIVES

Our aim was to assess the rates and predictors of PMN among NVAF patients who were newly prescribed an OAC.

METHODS

This was a retrospective database analysis of linked healthcare claims and electronic health record data. Adult NVAF patients with a prescription order for an OAC (apixaban, rivaroxaban, dabigatran, or warfarin) between January 2016 and June 2019 were identified (date of first prescription order = index date). Patients had a 1-year baseline and a 6-month post-index period to assess the rates of PMN, defined as having a prescription order but no paid claim for any OAC on or within 30 days after the index date. Sensitivity analyses explored 60-, 90- and 180-day PMN thresholds. Logistic regression models were used to examine the predictors of PMN.

RESULTS

Among 20,393 patients, the overall 30-day PMN rate was 28.4%; PMN rates decreased to 17% with a 180-day threshold. PMN was numerically lowest for warfarin among OACs and numerically lowest for apixaban among direct OACs. A CHA2DS2-VASc score of ≥ 3, commercial insurance, and African American race were associated with higher odds of PMN.

CONCLUSIONS

More than one-quarter of patients experienced PMN within 30 days of their initial prescription order. This rate decreased over a longer period, suggesting a delay in fills. Understanding the factors associated with PMN is warranted to develop effective interventions for improving OAC treatment rates in NVAF.

An Inconspicuous Offender: Apixaban-Induced Anticoagulant-Related Nephropathy

Direct oral anticoagulants (DOACs) have shifted the landscape of anticoagulation over the past decade, becoming a frequently used pharmaceutical agent. The increased use of DOACs for long-term anticoagulation has led to a rise in reported anticoagulant-related adverse reactions, such as anticoagulant-related nephropathy (ARN). The occurrence of ARN is well reported with warfarin; however, there are few cases of ARN reported with DOAC use. We report the case of an elderly man with coronary artery disease and hypertension who was initiated on apixaban for atrial fibrillation three years prior to presentation but developed rapid renal decline over the six months prior to presentation. The estimated glomerular filtration rate (eGFR) had decreased precipitously from 48 mL/min/1.73 m2 to 19 mL/min/1.73 m2 with a concurrent drop in hemoglobin in the setting of persistent microscopic hematuria. A renal biopsy showed red blood cell casts consistent with glomerular hematuria, despite no crescents or signs of other forms of glomerulonephritis. The patient's renal function ceased to deteriorate and had a 35% recovery (serum creatinine 2.6 mg/dL, eGFR 25 mL/min/1.73 m2) after the discontinuation of apixaban and conversion to rivaroxaban without the use of corticosteroids. The patient reported at follow-up that he discontinued rivaroxaban four days after initiation on his own accord due to extrarenal bleeding. Our case highlights the importance of prompt recognition and treatment of the underreported but potentially significant incidence of ARN with apixaban in a patient with an otherwise unexplained kidney injury.

Association between serum apolipoprotein A1 and atrial fibrillation in the Chinese population: a case-control study

BACKGROUND

The relationship between serum apolipoprotein A1 (APOA1) and atrial fibrillation (AF) is not known. Therefore, we sought to investigate the associations between APOA1 and AF in the Chinese population.

METHODS

This case-control study included 950 patients with AF (29-83 years old, 50.42% male) who were hospitalized consecutively in China between January 2019 and September 2021. Controls with sinus rhythm and without AF were matched (1:1) to cases by sex and age. Pearson correlation analysis was performed to investigate the correlation between APOA1 and blood lipid profiles. Multivariate regression models were used to explore the association between APOA1 and AF. The receiver operator characteristic (ROC) curve was constructed to examine the performance of APOA1.

RESULTS

Multivariate regression analysis showed that low serum APOA1 in men and women with AF was significantly associated with AF (OR = 0.261, 95% CI: 0.162-0.422, P < 0.001). Pearson correlation analysis indicated that serum APOA1 was positively correlated with total cholesterol (TC) (r = 0.456, p < 0.001), low-density lipoprotein cholesterol (LDL-C) (r = 0.825, p < 0.001), high-density lipoprotein cholesterol (HDL-C) (r = 0.238, p < 0.001), and apolipoprotein B (APOB) (r = 0.083, p = 0.011). ROC curve analysis showed that APOA1 levels of 1.105 g/L and 1.205 g/L were the optimal cut-off values for predicting AF in males and females, respectively.

CONCLUSION

Low APOA1 in male and female patients is significantly associated with AF in the Chinese population of non-statin users. APOA1 may be a potential biomarker for AF and contribute to the pathological progression of AF along with low blood lipid profiles. Potential mechanisms remain to be further explored.

Relation between laxative use and risk of major bleeding in patients with atrial fibrillation and heart failure

Constipation has been reported to increase the risk of cardiovascular mortality. Patients with atrial fibrillation (AF) and heart failure (HF) have more comorbidities and an increased bleeding risk. However, it remains unclear whether constipation is associated with an increased risk of incident bleeding complications in AF with HF. Here, we investigated the association between constipation requiring laxatives and major bleeding in AF and HF. We retrospectively analyzed the medical records of 370 consecutive patients hospitalized for AF and congestive HF. Constipation was defined as regularly taking laxatives or having at least two prescriptions for a ≥ 30-day supply of laxatives. Sixty patients experienced major bleeding events during a median follow-up of 318 days. The most common sites of bleeding were lower gastrointestinal (28%, 17/60), upper gastrointestinal (27%, 16/60), and intracranial (20%, 12/60). There were 33 (55%) patients with constipation in the bleeding group and 107 (35%) in the non-bleeding group (P = 0.004). Multivariate Cox regression analysis adjusted for HAS-BLED score, hemoglobin, and direct oral anticoagulant use showed that constipation (hazard ratio [HR] 1.85, 95% confidence interval [CI] 1.11-3.08; p = 0.019) was a significant risk factor for major bleeding. We found a significant association between constipation requiring laxatives and major bleeding in patients with AF and HF. These findings indicate the need for constipation prevention in these patients to avoid reliance on invasive defecation management, including laxatives.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants Versus Warfarin Among Adults With Cancer and Atrial Fibrillation

BACKGROUND

While clinical guidelines recommend direct-acting oral anticoagulants (DOAC) over warfarin to treat isolated nonvalvular atrial fibrillation, guidelines are silent regarding nonvalvular atrial fibrillation treatment among individuals with cancer, reflecting the paucity of evidence in this setting. We quantified relative risk of ischemic stroke or systemic embolism and major bleeding (primary outcomes), and all-cause and cardiovascular death (secondary outcomes) among older individuals with cancer and nonvalvular atrial fibrillation comparing DOACs and warfarin.

METHODS

This retrospective cohort study used Surveillance, Epidemiology, and End Results cancer registry and linked US Medicare data from 2010 through 2016, and included individuals diagnosed with cancer and nonvalvular atrial fibrillation who newly initiated DOAC or warfarin. We used inverse probability of treatment weighting to control confounding. We used competing risk regression for primary outcomes and cardiovascular death, and Cox proportional hazard regression for all-cause death.

RESULTS

Among 7675 individuals included in the cohort, 4244 (55.3%) received DOACs and 3431 (44.7%) warfarin. In the inverse probability of treatment weighting analysis, there was no statistically significant difference among DOAC and warfarin users in the risk of ischemic stroke or systemic embolism (1.24 versus 1.19 events per 100 person-years, adjusted hazard ratio 1.41 [95% CI, 0.92-2.14]), major bleeding (3.08 versus 4.49 events per 100 person-years, adjusted hazard ratio 0.90 [95% CI, 0.70-1.17]), and cardiovascular death (1.88 versus 3.14 per 100 person-years, adjusted hazard ratio 0.82 [95% CI, 0.59-0.1.13]). DOAC users had significantly lower risk of all-cause death (7.09 versus 13.3 per 100 person-years, adjusted hazard ratio 0.81 [95% CI, 0.69-0.94]) compared to warfarin users.

CONCLUSIONS

Older adults with cancer and atrial fibrillation exposed to DOACs had similar risks of stroke and systemic embolism and major bleeding as those exposed to warfarin. Relative to warfarin, DOAC use was associated with a similar risk of cardiovascular death and a lower risk of all-cause death.

Direct oral anticoagulants versus vitamin K antagonists in the treatment of left ventricular thrombosis: a systematic review and meta-analysis

INTRODUCTION

Evidence about the use of direct oral anticoagulants (DOACs) in patients with left ventricular thrombosis (LVT) are emerging. The aim of our study was to provide a comprehensive synthesis of the available evidence concerning the clinical effects of DOACs versus vitamin K antagonists (VKAs) in LVT treatment.

EVIDENCE ACQUISITION

Systematic search of studies evaluating DOACs versus VKAs use in patients with LVT was performed on May 11^th, 2021. Data were pooled by meta-analysis using a random-effects model. Odds ratios (OR) with relative 95% confidence intervals (CI) were used as measures of effect estimates. The primary efficacy and safety endpoint were ischemic stroke and any bleeding, respectively. Secondary endpoints were LVT resolution, systemic embolism, major bleeding, hemorrhagic stroke, and all cause death.

EVIDENCE SYNTHESIS

Twenty studies were included in the meta-analysis: 1,391 patients were treated with DOACs and 1,534 with VKAs. A significant reduction in the risk of ischemic stroke (OR 0.67, 95% CI, 0.45-0.98, P=0.048, number needed to treat to benefit [NNTB] 22 [95% CI 15-43]) and any bleeding (OR 0.64, 95% CI 0.46-0.89, P=0.009, NNTB 26 [95% CI 16-80]) was observed with DOACs compared to VKAs. No statistically significant difference was observed among the two treatment arms for the secondary endpoints.

CONCLUSIONS

Compared to VKAs, DOACs are associated with a reduced risk of ischemic stroke and bleeding. In light of these findings, and the practical advantages of DOACs, additional large scale randomized controlled trials are needed to confirm the benefits of DOACs in patients with LVT.

Rationale, Design and Methods of the Prospective Record of the Use of Dabigatran in Patients with Acute Stroke or TIA (PRODAST) Study

Background

The optimal timing of anticoagulation following acute ischaemic stroke or TIA in patients with atrial fibrillation (AF) is a frequent challenge. Early initiation of anticoagulation can reduce the risk for recurrent ischaemic events, but may lead to an increased risk for intracerebral haemorrhage.

Aim

The Prospective Record of the Use of Dabigatran in Patients with Acute Stroke or TIA (PRODAST) study was initiated to investigate outcome events under antithrombotic therapy after ischaemic stroke or TIA in patients with AF. The main objective is to compare the three-month rates of major haemorrhagic events between early (≤ 7 days) versus late (> 7 days) administration of dabigatran or treatment with vitamin-K antagonists started at any time. Occurrences of ischaemic and major haemorrhagic events will be evaluated to determine the optimal time point for initiation or resumption of anticoagulation.

Design and Methods

PRODAST is a prospective, multicenter, observational, non-interventional post-authorization safety study. 10,000 patients with recent (≤ 1 week from index event) ischaemic stroke or TIA and non-valvular AF were recruited at 86 German sites starting in July 2015. The observational plan includes a baseline visit, documentation of data during hospitalization and a telephone-based, central follow-up at three months after the index event. The primary endpoint is the major bleeding rate within three months. Secondary endpoints include rates of recurrent ischaemic or haemorrhagic stroke, TIA, systemic embolism, myocardial infarction and death.

Summary

PRODAST will provide important real-world data on safety and efficacy of antithrombotic therapy after acute stroke and TIA in patients with AF.

Atrial fibrillation: trends in prevalence and antithrombotic prescriptions in the community

Introduction

In the past decade, the atrial fibrillation (AF) landscape, including the treatment modalities, has drastically changed. This raises the question how AF prevalence and choices in antithrombotic therapy prescription have developed in the community over time.

Methods

Routine care data from the Julius General Practitioners’ Network (JGPN) were used to calculate the yearly prevalence of AF and to quantify the percentage of all patients who were prescribed a platelet inhibitor, vitamin K antagonist (VKA), non-VKA oral anticoagulant (NOAC) or no antithrombotic medication. To explore whether certain patient characteristics are associated with selective prescription of oral anticoagulants (OAC), we applied logistic regression analyses.

Results

From 2008 through 2017, the JGPN database included 7459 unique AF patients. During this period, the prevalence of AF increased from 0.4% to 1.4%. The percentage of patients prescribed a VKA declined from 47% to 41%, whereas the percentage of patients prescribed a NOAC rose from 0% to 20%. In patients with new-onset AF, older age, heart failure, diabetes mellitus, vascular disease and dementia were independently associated with a higher likelihood of VKA rather than NOAC prescription. In 2017, 25% of all patients with AF and a CHA₂DS₂-VASc score ≥ 2 were not prescribed OAC therapy (i.e. 8% with platelet inhibitor monotherapy and 17% without any antithrombotic therapy).

Conclusion

Between 2008 and 2017, AF prevalence in the community more than tripled. Prescription patterns showed possible ‘channelling’ of VKAs over NOACs in frailer, elderly patients, whereas still about one in every four AF patients with a CHA₂DS₂-VASc score ≥ 2 was not prescribed any prophylactic OAC therapy.

Supplementary Information

The online version of this article (10.1007/s12471-022-01667-x) contains supplementary material, which is available to authorized users.

[The Effect of Anticoagulant in Patients with Cirrhosis Associated with Acute Portal Vein Thrombosis]

The treatment of portal vein thrombosis (PVT) in patients with liver cirrhosis (LC) has been controversial, and it is generally case- and institution-dependent. The occurrence of acute or extensive PVT is critical and requires urgent treatment because it is usually accompanied by symptoms, particularly when total occlusion occurs, causing acute decompensation of liver disease. Even in severe cases, drug selection and treatment duration are determined based on each institution's experience. Therefore, consistent guidelines for the treatment of patients with LC with PVT are required. Recently, a patient with acute occlusive PVT with LC who showed signs of acute decompensation was treated by administering low molecular weight heparin as anticoagulant therapy. After anticoagulant treatment, the portal vein was almost completely recanalized, and the deteriorated liver function improved. In addition, the patient recovered well and showed no recurrence of PVT for more than a year. Thus, the most recent knowledge regarding the treatment of nonmalignant PVT in LC was reviewed along with a case report.

Mendelian randomization study on atrial fibrillation and cardiovascular disease subtypes

Atrial fibrillation (AF) has been associated with numerous diseases. However, whether AF is a cause or consequence of these diseases is uncertain. To clarify, we assessed the causal role of AF on ischemic heart disease (IHD), stroke, other cardiovascular disease (CVD) subtypes, type 2 diabetes mellitus (T2DM), and late-onset AD using bi-directional two-sample Mendelian randomization (MR) among people primarily of European descent. Genetically predicted log odds of AF was associated with any stroke (odds ratio (OR) 1.22, 95% CI 1.18 to 1.27), particularly cardioembolic stroke and possibly subdural hemorrhage, with sensitivity analyses showing similar positive findings. Genetically predicted AF was also associated with arterial thromboembolism (1.32, 1.13 to 1.53), and heart failure (1.26, 1.21 to 1.30). No association of genetically predicted AF with IHD, T2DM, cognitive function, or late-onset AD was found. Conversely, genetically predicted IHD, heart failure and possibly ischemic stroke, particularly cardioembolic stroke, were positively associated with AF. Atrial fibrillation plays a role in any stroke, arterial thromboembolism, and heart failure, corroborating current clinical guidelines on the importance of preventing these complications by effective AF management. In addition, patients with IHD, heart failure or possibly ischemic stroke might be predisposed to developing AF, with implications for management.

Global access to affordable direct oral anticoagulants

Poor control of cardiovascular disease accounts for a substantial proportion of the disease burden in developing countries, but often essential anticoagulant medicines for preventing strokes and embolisms are not widely available. In 2019, direct oral anticoagulants were added to the World Health Organization’s WHO Model list of essential medicines. The aims of this paper are to summarize the benefits of direct oral anticoagulants for patients with cardiovascular disease and to discuss ways of increasing their usage internationally. Although the cost of direct oral anticoagulants has provoked debate, the affordability of introducing these drugs into clinical practice could be increased by: price negotiation; pooled procurement; competitive tendering; the use of patent pools; and expanded use of generics. In 2017, only 14 of 137 countries that had adopted national essential medicines lists included a direct oral anticoagulant on their lists. This number could increase rapidly if problems with availability and affordability can be tackled. Once the types of patient likely to benefit from direct oral anticoagulants have been clearly defined in clinical practice guidelines, coverage can be more accurately determined and associated costs can be better managed. Government action is required to ensure that direct oral anticoagulants are covered by national budgets because the absence of reimbursement remains an impediment to achieving universal coverage. Tackling cardiovascular disease with the aid of direct oral anticoagulants is an essential component of efforts to achieve the World Health Organization’s target of reducing premature deaths due to noncommunicable disease by 25% by 2025.

A study of anticoagulant therapy in patients with coronary artery disease

OBJECTIVES

One of the methods used to treat coronary artery disease (CAD) is anticoagulant therapy, which involves administering anticoagulants to patients that inhibit the arrangement and actuation of clotting factors. Anticoagulant therapy in patients with CAD must be monitored and evaluated because its greatest side effect is the risk of bleeding. The research aimed to analyze anticoagulants used in therapy for CAD patients and identify potential adverse drug reactions and adverse drug interactions.

METHODS

This was an observational study which collected data retrospectively at Bhayangkara Hospital Surabaya. Patient data had to meet the requirements for inclusion, which were patients treated for a diagnosis of CAD with anticoagulant therapy and were in conditions with or without complications and comorbid diseases. Data were obtained from 40 patient medical records. The data were then processed descriptively.

RESULTS

Most patients were male (80%) and aged 61-70 years old (37.5%). Fondaparinux was administered to 18 patients at a dose of 1 × 2.5 mg SC. Furthermore, enoxaparin was administered to 15 patients at a dose of 2 × 60 mg SC, and seven patients received warfarin at a dose of 1 × 2-4 mg per oral.

CONCLUSIONS

The anticoagulants used in this study were fondaparinux 1 × 2.5 mg SC (45%), enoxaparin 2 × 60 mg SC (37.5%), and warfarin 1 × 2-4 mg PO (17.5%). Side effects of the anticoagulants were absent. However, drug interactions with aspirin, clopidogrel, and allopurinol increased the risk of bleeding.

Comparative effectiveness of oral anticoagulants in everyday practice

OBJECTIVES

This study evaluated the comparative effectiveness of vitamin K antagonists (VKAs), direct thrombin inhibitors (DTIs) and factor Xa inhibitors (FXaI) in patients with atrial fibrillation (AF) at risk of stroke in everyday practice.

METHODS

Data from patients with AF and Congestive heart failure, Hypertension, Age 75 years, Diabetes mellitus, prior Stroke, TIA, or thromboembolism, Vascular disease, Age 65-74 years, Sex category (CHA2DS2-VASc) score ≥2 (excluding gender) in the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation registry were analysed using an improved method of propensity weighting, overlap weights and Cox proportional hazards models.

RESULTS

All-cause mortality, non-haemorrhagic stroke/systemic embolism (SE) and major bleeding over 2 years were compared in 25 551 patients, 7162 (28.0%) not treated with oral anticoagulant (OAC) and 18 389 (72.0%) treated with OAC (FXaI (41.8%), DTI (11.4%) and VKA (46.8%)). OAC treatment compared with no OAC treatment was associated with decreased risk of all-cause mortality (HR 0.82 (95% CI 0.74 to 0.91)) and non-haemorrhagic stroke/SE (HR 0.71 (95% CI 0.57 to 0.88)) but increased risk of major bleeding (HR 1.46 (95% CI 1.15 to 1.86)). Non-vitamin K antagonist oral anticoagulant (NOAC) use compared with no OAC treatment was associated with lower risks of all-cause mortality and non-haemorrhagic stroke/SE (HR 0.67 (95% CI 0.59 to 0.77)) and 0.65 (95% CI 0.50 to 0.86)) respectively, with no increase in major bleeding (HR 1.10 (95% CI 0.82 to 1.47)). NOAC use compared with VKA use was associated with lower risk of all-cause mortality and major bleeding (rates/100 patient-years 3.6 (95% CI 3.3 to 3.9) vs 4.8 (95% CI 4.5 to 5.2) and 1.0 (95% CI 0.9 to 1.1) vs 1.4 (95% CI 1.2 to 1.6); HR 0.79 (95% CI 0.70 to 0.89) and 0.77 (95% CI 0.61 to 0.98) respectively), with similar risk of non-haemorrhagic stroke/SE (rates/100 patient-years 0.8 (95% CI 0.7 to 0.9) versus 1.0 (95% CI 0.8 to 1.1); HR 0.96 (95% CI 0.73 to 1.25).

CONCLUSION

Important benefits in terms of mortality and major bleeding were observed with NOAC versus VKA with no difference among NOAC subtypes.

TRIAL REGISTRATION NUMBER

NCT01090362.

Direct oral anticoagulants for the treatment and prevention of venous thromboembolism in patients with cancer: current evidence

Venous thromboembolic disease (VTED) is a common and clinically important complication in patients with cancer, contributing to its mortality and morbidity. Direct oral anticoagulant agents (DOACs), including direct thrombin inhibitors and direct factor Xa inhibitors, are as effective as vitamin K antagonists for the treatment of VTED and are associated with less frequent and severe bleeding. They have advantages over low-molecular-weight heparin, but comparative long-term efficacy and safety data are lacking for these compounds. Recent randomized clinical trials suggest a role for DOACs in the treatment of VTED in patients with cancer. This review will discuss the existing evidence and future perspectives on the role of DOACs in the treatment of VTE based on the current evidence about their overall efficacy and safety and the limited information in patients with cancer; in addition, we will briefly review their pharmacokinetic properties with special reference to potential interactions.

The efficacy and safety of edoxaban versus warfarin in preventing clinical events in atrial fibrillation: A systematic review and meta-analysis

Atrial fibrillation (AF) is the most common type of arrhythmia. Warfarin reduces the incidence and mortality of strokes in patients with AF. Edoxaban reduces the bleeding risk in patients with AF. This study evaluates the efficacy and safety of edoxaban versus warfarin in preventing clinical events in patients with AF through a meta-analysis of randomized controlled trials (RCTs). RCTs were retrieved from medical literature databases. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated to compare the primary and safety endpoints. In total, five articles (10 trial comparisons) containing 24,836 patients were retrieved. Of these patients, 16,268 (65.5%) received edoxaban and 8,568 (34.5%) received warfarin. Compared with warfarin, edoxaban significantly reduced the incidence of cardiovascular death (CVD), major bleeding, and non-major bleeding (RR: 0.86, 95% CI: 0.80-0.93, I2 : 0.0%; RR: 0.65, 95% CI: 0.59-0.71, I2 : 75.6%; and RR: 0.80, 95% CI: 0.77-0.84, I2 : 79.3%, respectively). Edoxaban did not increase the incidence of stroke, systemic embolic events, myocardial infarction, and adverse events compared with warfarin (RR: 1.00, 95% CI: 0.90-1.11, I2 : 42.8%; RR: 1.00, 95% CI: 0.67-1.49, I2 : 0.0%; RR: 1.08, 95% CI: 0.93-1.27, I2 : 0.0%; RR: 1.00, 95% CI: 0.91-1.10, I2: 46.4%, respectively). This meta-analysis indicated that compared with warfarin, edoxaban can significantly reduce the incidence of CVD and major and non-major bleeding. The anticoagulant effect and safety of edoxaban may be better than those of warfarin.

A meta-epidemiological study of subgroup analyses in cochrane systematic reviews of atrial fibrillation

BACKGROUND

Information on subgroup assessments in systematic reviews (SR) of atrial fibrillation (AF) is limited. This review aims to describe subgroup analyses in AF SRs to inform the design of SRs and randomized trials as well as clinical practice.

METHODS

We conducted a cross sectional meta-epidemiological study of Cochrane AF reviews by searching AF (including variants) in the title, abstract, or keyword field without date or language restrictions (Issue 9; September 2018). Two reviewers independently extracted study characteristics to summarize frequency of subgroups pre-specified and conducted and report credibility of subgroup effects claimed.

RESULTS

Of 39 Cochrane reviews identified, 17 met inclusion criteria (including 168 reports of 127 randomized trials) and the majority (16; 94.1%) conducted meta-analysis of outcomes. Most (13; 76.5%) planned pre-specified subgroup analyses; 7 of which (41.2%) conducted subgroups. In these 7 reviews, 56 subgroups were planned, 17 (30.4%) conducted and 6 (10.7%) yielded subgroup effects. Variables such as co-morbid disease, stroke risk factors, prior stroke/transient ischemic attack, age, race, and sex represented 44% (24 subgroups) of all planned subgroups (8 conducted; 14.3%); however, information on covariate selection was lacking. Overall, more subgroups were planned than conducted (mean difference (95% CI) 2.3 (1.2-3.5, p < 0.001)). Of all subgroups conducted, anticoagulant characteristics comprised a third of all subgroup effects (n = 5, 35.7%). The credibility of subgroups identified (n = 14) was assessed and less than half (43%) represented one of a small number of pre-specified hypothesis and rarely were effects seen within studies (7%). Of 5 reviews that reported subgroup effects, only 3 discussed subgroup effects as part of the overall conclusions; none discussed credibility of subgroup effects.

CONCLUSIONS

This meta-epidemiological review of a subset of Cochrane AF reviews suggests that planning and reporting of subgroup analyses in AF reviews can be improved to better inform clinical management. Most pre-specified subgroup analyses were not performed, important variables (such as stroke, bleeding risk, and other comorbidities) were rarely examined and credibility of subgroup effects claimed was low. Future reviews should aim to identify important subgroups in their protocols and use recommended approaches to test subgroup effects in order to better support clinical decision-making.

Meta-analysis of haematoma volume, haematoma expansion and mortality in intracerebral haemorrhage associated with oral anticoagulant use

OBJECTIVE

To obtain precise estimates of age, haematoma volume, secondary haematoma expansion (HE) and mortality for patients with intracerebral haemorrhage (ICH) taking oral anticoagulants [Vitamin K antagonists (VKA-ICH) or non-Vitamin K antagonist oral anticoagulants (NOAC-ICH)] and those not taking oral anticoagulants (non-OAC ICH) at ICH symptom onset.

METHODS

We conducted a systematic review and meta-analysis of studies comparing VKA-ICH or NOAC-ICH or both with non-OAC ICH. Primary outcomes were haematoma volume (in ml), HE, and mortality (in-hospital and 3-month). We calculated odds ratios (ORs) using the Mantel-Haenszel random-effects method and corresponding 95% confidence intervals (95%CI) and determined the mean ICH volume difference.

RESULTS

We identified 19 studies including data from 16,546 patients with VKA-ICH and 128,561 patients with non-OAC ICH. Only 2 studies reported data on 4943 patients with NOAC-ICH. Patients with VKA-ICH were significantly older than patients with non-OAC ICH (mean age difference: 5.55 years, 95%CI 4.03-7.07, p < 0.0001, I² = 92%, p < 0.001). Haematoma volume was significantly larger in VKA-ICH with a mean difference of 9.66 ml (95%CI 6.24-13.07 ml, p < 0.00001; I² = 42%, p = 0.05). HE occurred significantly more often in VKA-ICH (OR 2.96, 95%CI 1.74-4.97, p < 0.00001; I² = 65%). VKA-ICH was associated with significantly higher in-hospital mortality (VKA-ICH: 32.8% vs. non-OAC ICH: 22.4%; OR 1.83, 95%CI 1.61-2.07, p < 0.00001, I² = 20%, p = 0.27) and 3-month mortality (VKA-ICH: 47.1% vs. non-OAC ICH: 25.5%; OR 2.24, 95%CI 1.52-3.31, p < 0.00001, I² = 71%, p = 0.001). We did not find sufficient data for a meta-analysis comparing NOAC-ICH and non-OAC-ICH.

CONCLUSION

This meta-analysis confirms, refines and expands findings from prior studies. We provide precise estimates of key prognostic factors and outcomes for VKA-ICH, which has larger haematoma volume, increased rate of HE and higher mortality compared to non-OAC ICH. There are insufficient data on NOACs.

Pharmaceutical industry funding of events for healthcare professionals on non-vitamin K oral anticoagulants in Australia: an observational study

OBJECTIVES

To describe the nature, frequency and content of non-vitamin K oral anticoagulant (NOAC)-related events for healthcare professionals sponsored by the manufacturers of the NOACs in Australia. A secondary objective is to compare these data to the rate of dispensing of the NOACs in Australia.

DESIGN AND SETTING

This cross-sectional study examined consolidated data from publicly available Australian pharmaceutical industry transparency reports from October 2011 to September 2015 on NOAC-related educational events. Data from April 2011 to June 2016 on NOAC dispensing, subsidised under Australia's Pharmaceutical Benefits Scheme (PBS), were obtained from the Department of Health and the Department of Human Services.

MAIN OUTCOME MEASURES

Characteristics of NOAC-related educational events including costs (in Australian dollars, $A), numbers of events, information on healthcare professional attendees and content of events; and NOAC dispensing rates.

RESULTS

During the study period, there were 2797 NOAC-related events, costing manufacturers a total of $A10 578 745. Total expenditure for meals and beverages at all events was $A4 238 962. Events were predominantly attended by general practitioners (42%, 1174/2797), cardiologists (35%, 977/2797) and haematologists (23%, 635/2797). About 48% (1347/2797) of events were held in non-clinical settings, mainly restaurants, bars and cafes. Around 55% (1551/2797) of events consisted of either conferences, meetings or seminars. The analysis of the content presented at two events detected promotion of NOACs for unapproved indications, an emphasis on a favourable benefit/harm profile, and that all speakers had close ties with the manufacturers of the NOACs. Following PBS listings relevant to each NOAC, the numbers of events related to that NOAC and the prescribing of that NOAC increased.

CONCLUSIONS

Our findings suggest that the substantial investment in NOAC-related events made by four pharmaceutical companies had a promotional purpose. Healthcare professionals should seek independent information on newly subsidised medicines from, for example, government agencies or drug bulletins.

Apixaban in Comparison to Warfarin for Stroke Prevention in Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-Analysis of Observational Studies

Introduction

Atrial fibrillation leads to increased risk of systemic embolism and stroke. To decrease these adverse events, anticoagulation is routinely prescribed. Nonvitamin K anticoagulants like apixaban and rivaroxaban are becoming popular and being used more frequently nowadays. We here compare the efficacy and safety of apixaban with those of warfarin.

Methods and Analysis

This systematic review aims to assess the efficacy and safety of apixaban compared to those of warfarin. Eligible participants were adults diagnosed with nonvalvular atrial fibrillation. The intervention was apixaban, and the comparator was warfarin. The primary efficacy endpoint is the first admission with systemic embolism or stroke, and the primary safety outcome is the occurrence of major bleeding. Relevant studies were searched in the Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, and clinicaltrials.gov. After being independently reviewed by two authors, five articles were included in the systematic review. The risk of bias of included studies was assessed using the Cochrane risk of bias tool and SIGN methodology. The RevMan software was used to assess the effect size and perform meta-analysis.

Results

Apixaban was found to be superior to warfarin in terms of safety (RR 0.58; CI 0.52-0.66) but not superior to warfarin in terms of efficacy (RR 0.93; CI 0.70-1.24).

Conclusion

Apixaban is superior to warfarin in terms of safety, but no difference in efficacy is noted. The choice of anticoagulation should be individualized based on the risk factor profile of the patient.

A Population-Based Study of Incidence, Presentation, Management and Outcome of Primary Thromboembolic Ischemia in the Upper Extremity

OBJECTIVES

To investigate the epidemiology of acute upper limb thromboembolism in a well-defined Norwegian population.

METHODS

This study was a retrospective, single-center, observational population-based cohort study of acute upper limb thromboembolism. The study included all patients from the hospital's primary catchment area from January 2000 to December 2015. Age- and gender-adjusted incidence rates were calculated using population demographics from Statistics Norway.

RESULTS

A total of 54 patients were identified, of which 49 were included in the analyses: 27 (55%) females (median age 83 years, range 40-96) and 22 (45%) males (median age 70 years, range 42-95) (P = .053). The adjusted incidence rate for the period was 1.6 patients per 100,000 inhabitants per year (95% confidence interval 1.2-2.2) and did not change significantly during the period studied. Atrial fibrillation was detected by electrocardiography in 30 (61%) patients; in this group, 10 patients were on warfarin but only two had an international normalized ratio > 1.9 and the remaining 20 were not anticoagulated. Altogether, 38 (78%) patients underwent surgery, 1 (2%) was treated with thrombolysis, and the remaining patients were treated conservatively; no amputations were performed. Four patients (8%) died within 30 days, and 12 of the surviving 45 patients (27%) had recurrent thromboembolism.

CONCLUSION

The incidence rate was stable during the study period. Patients with upper limb thromboembolism due to atrial fibrillation were inadequately anticoagulated. One in four patients experienced a recurrent thromboembolic event. Lifelong anticoagulation should be considered in all patients with upper limb thromboembolism.

Direct oral anticoagulants versus vitamin K antagonists after recent ischemic stroke in patients with atrial fibrillation

Objective

We compared outcomes after treatment with direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) in patients with atrial fibrillation (AF) and a recent cerebral ischemia.

Methods

We conducted an individual patient data analysis of seven prospective cohort studies. We included patients with AF and a recent cerebral ischemia (<3 months before starting oral anticoagulation) and a minimum follow‐up of 3 months. We analyzed the association between type of anticoagulation (DOAC versus VKA) with the composite primary endpoint (recurrent ischemic stroke [AIS], intracerebral hemorrhage [ICH], or mortality) using mixed‐effects Cox proportional hazards regression models; we calculated adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs).

Results

We included 4,912 patients (median age, 78 years [interquartile range {IQR}, 71–84]; 2,331 [47.5%] women; median National Institute of Health Stroke Severity Scale at onset, 5 [IQR, 2–12]); 2,256 (45.9%) patients received VKAs and 2,656 (54.1%) DOACs. Median time from index event to starting oral anticoagulation was 5 days (IQR, 2–14) for VKAs and 5 days (IQR, 2–11) for DOACs (p = 0.53). There were 262 acute ischemic strokes (AISs; 4.4%/year), 71 intracranial hemorrrhages (ICHs; 1.2%/year), and 439 deaths (7.4%/year) during the total follow‐up of 5,970 patient‐years. Compared to VKAs, DOAC treatment was associated with reduced risks of the composite endpoint (HR, 0.82; 95% CI, 0.67–1.00; p = 0.05) and ICH (HR, 0.42; 95% CI, 0.24–0.71; p < 0.01); we found no differences for the risk of recurrent AIS (HR, 0.91; 95% CI, 0.70–1.19; p = 0.5) and mortality (HR, 0.83; 95% CI, 0.68–1.03; p = 0.09).

Interpretation

DOAC treatment commenced early after recent cerebral ischemia related to AF was associated with reduced risk of poor clinical outcomes compared to VKA, mainly attributed to lower risks of ICH. ANN NEUROL 2019;85:823–834.

Timing of anticoagulation after recent ischaemic stroke in patients with atrial fibrillation

BACKGROUND

About 13-26% of all acute ischaemic strokes are related to non-valvular atrial fibrillation, the most common cardiac arrhythmia globally. Deciding when to initiate oral anticoagulation in patients with non-valvular atrial fibrillation is a longstanding, common, and unresolved clinical challenge. Although the risk of early recurrent ischaemic stroke is high in this population, early oral anticoagulation is suspected to increase the risk of potentially harmful intracranial haemorrhage, including haemorrhagic transformation of the infarct. This assumption, and current treatment guidelines, are based on historical, mostly observational data from patients with ischaemic stroke and atrial fibrillation treated with heparins, heparinoids, or vitamin K antagonists (VKAs) to prevent recurrent ischaemic stroke. Randomised controlled trials have subsequently shown that direct oral anticoagulants (DOACs; ie, apixaban, dabigatran, edoxaban, and rivaroxaban) are at least as effective as VKAs in primary and secondary prevention of atrial fibrillation-related ischaemic stroke, with around half the risk of intracranial haemorrhage. However, none of these DOAC trials included patients who had experienced ischaemic stroke recently (within the first few weeks). Clinicians therefore remain uncertain regarding when to commence DOAC administration after acute ischaemic stroke in patients with atrial fibrillation.

RECENT DEVELOPMENTS

Prospective observational studies and two small randomised trials have investigated the risks and benefits of early DOAC-administration initiation (most with a median delay of 3-5 days) in mild-to-moderate atrial fibrillation-associated ischaemic stroke. These studies reported that early DOAC treatment was associated with a low frequency of clinically symptomatic intracranial haemorrhage or surrogate haemorrhagic lesions on MRI scans, whereas later DOAC-administration initiation (ie, >7 days or >14 days after index stroke) was associated with an increased frequency of recurrent ischaemic stroke. WHERE NEXT?: Adequately powered randomised controlled trials comparing early to later oral anticoagulation with DOACs in ischaemic stroke associated with atrial fibrillation are justified to confirm the acceptable safety and efficacy of this strategy. Four such randomised controlled trials (collectively planned to include around 9000 participants) are underway, either using single cutoff timepoints for early versus late DOAC-administration initiation, or selecting DOAC-administration timing according to the severity and imaging features of the ischaemic stroke. The results of these trials should help to establish the optimal timing to initiate DOAC administration after recent ischaemic stroke and whether the timing should differ according to stroke severity. Results of these trials are expected from 2021.

Real-world adherence to oral anticoagulants in atrial fibrillation patients: a study protocol for a systematic review and meta-analysis

INTRODUCTION

Atrial fibrillation (AF) is one of the leading causes of cerebrovascular mortality and morbidity. Oral anticoagulants (OACs) have been shown to reduce the incidence of cardioembolic stroke in patients with AF, adherence to treatment being an essential element for their effectiveness. Since the release of the first non-vitamin K antagonist oral anticoagulant, several observational studies have been carried out to estimate OAC adherence in the real world using pharmacy claim databases or AF registers. This systematic review aims to describe secondary adherence to OACs, to compare adherence between OACs and to analyse potential biases in OAC secondary adherence studies using databases.

METHODS AND ANALYSIS

We searched on PubMed, SCOPUS and Web of Science databases (completed in 26 September 2018) to identify longitudinal observational studies reporting days' supply adherence measures with OAC in patients with AF from refill databases or AF registers. The main study endpoint will be the percentage of patients exceeding the 80% threshold in proportion of days covered or the medication possession ratio. Two reviewers will independently screen potential studies and will extract data in a structured format. A random-effects meta-analysis will be carried out to pool study estimates. The risk of bias will be assessed using the Newcastle-Ottawa Scale for observational studies and we will also assess some study characteristics that could affect days' supply adherence estimates.

ETHICS AND DISSEMINATION

This systematic review using published aggregated data does not require ethics approval according to Spanish law and international regulations. The final results will be published in a peer-review journal and different social stakeholders, non-academic audiences and patients will be incorporated into the diffusion activities.

PROSPERO REGISTRATION NUMBER

CRD42018095646.

Management of patients with stroke treated with direct oral anticoagulants

Since their market approval, direct oral anticoagulants (DOACs) are being increasingly used for stroke prevention in patients with atrial fibrillation. However, the management of DOAC-treated patients with stroke poses several challenges for physicians in everyday clinical practice, both in the acute setting and in long-term care. This has spurred extensive research activity in the field over the past few years, which we review here.