Comparative safety and effectiveness of non-vitamin K oral anticoagulants versus warfarin in patients with non-valvular atrial fibrillation: A network meta-analysis

BACKGROUND

The introduction of non-vitamin K antagonist oral anticoagulants (NOACs), with a non-inferior or superior clinical efficacy profile compared to vitamin K antagonists (VKAs), has significantly improved the safety profile and treatment adherence of patients with non-valvular atrial fibrillation (AF). However, few studies have compared the effectiveness and safety of NOACs. Therefore, we conducted this systematic review and network meta-analysis to compare the safety and clinical effectiveness of NOACs and VKAs in patients with non-valvular AF.

METHODS

An online bibliographic search was conducted to retrieve real-world evidence studies published between January 2019 and June 2022.

RESULTS

Dabigatran was associated with lower risks of major bleeding, ischemic stroke, and intracranial hemorrhage than warfarin. Among the NOACs, only dabigatran had a lower risk of all-cause mortality than warfarin. Dabigatran was also associated with lower risks of major bleeding and intracranial hemorrhage than rivaroxaban.

CONCLUSION

Our meta-analysis confirms that dabigatran's real-world safety and clinical effectiveness align with the results of pivotal clinical trials.

Appropriateness of prescribing profiles and intake adherence to non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation: analysis of a retrospective longitudinal study using real-world data from Northern Portugal (AF-React Study)

OBJECTIVES

This study aimed to assess the appropriateness of prescribing profiles and intake adherence to non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation (AF).

DESIGN

Retrospective longitudinal study.

SETTING

The study was conducted in the Regional Health Administration of Northern Portugal.

PARTICIPANTS

The authors selected a database of 21 854 patients with prescriptions for NOACs between January 2016 and December 2018 and were classified with AF until December 2018.

OUTCOME MEASURES

The appropriate dosage of NOAC for patients with AF divided into three categories: contraindicated, inconsistent and consistent, based on the 2020 European Society of Cardiology guidelines for AF.

RESULTS

Dabigatran had a lower percentage of guideline-consistent doses (n=1657, 50.1%) than other drugs such as rivaroxaban (n=4737, 81.6%), apixaban (n=3830, 78.7%) and edoxaban (n=436, 82.1%). Most patients with an inconsistent dose were prescribed a lower dose than recommended based on their glomerular filtration rate (GFR). Among patients younger than 75 years with GFR >60 mL/min, 59.8% (n=10 028) had an adequate GFR range, while 27.8% (n=7166) of GFR measurements from patients older than 75 years old and 29.4% (n=913) of GFR measurements from patients younger than 75 years with GFR <60 mL/min were within an adequate time range. Adherence to NOACs varied across different drugs, with 59.1% (n=540) adhering to edoxaban, 56.3% (n=5443) to rivaroxaban, 55.3% (n=3143) to dabigatran and 53.3% (n=4211) to apixaban.

CONCLUSIONS

Dabigatran had the lowest percentage of guideline-consistent doses. Patients younger than 75 years with GFR >60 mL/min had the highest percentage with an adequate GFR range, while other groups who require closer GFR monitoring had lower percentages within an adequate GFR range. Adherence to NOACs differed among different drugs, with greater adherence to treatment with edoxaban and less adherence to apixaban.

Effect of different oral anticoagulants on cognitive function in patients with atrial fibrillation: A Bayesian network meta-analysis

BACKGROUND

Atrial fibrillation (AF) is 1 of the most common types of arrhythmias. At present, the treatment for patients with AF mainly includes oral anticoagulants (OACs). Studies have shown that OACs are associated with cognitive decline in patients with atrial fibrillation; however, there is a lack of relevant evidence. This study used Bayesian network meta-analysis (NMA) to investigate the effects of different oral anticoagulants on cognitive decline in patients with AF.

METHODS

We systematically searched for clinical studies on oral anticoagulants in patients with AF in PubMed, Web of Science, Embase, and the Cochrane Library as of July 3, 2023. Cochrane's randomized controlled trial bias risk assessment tool and the Newcastle-Ottawa Scale were used to assess the bias risk of the included studies. The main outcome measure was decreased cognitive functioning.

RESULTS

Ten studies were included, including 2 RCTs and 7 RCSs, including 882,847 patients with AF. Five oral anticoagulants and 2 anticoagulants were included: VKAs (especially warfarin), Dabigatran, Edoxaban, Rivaroxaban, Apixaban, and Aspirin, Clopidogrel. The results of the mesh meta-analysis showed that VKAs were superior to warfarin in reducing the risk of cognitive decline in patients with AF (OR = -1.19, 95% CI (-2.35, -0.06), P < .05) (Table 5). The top 3 drugs in terms of the probability of reducing the incidence of cognitive impairment in patients with AF with different oral anticoagulants were VKAs (87%), rivaroxaban (62.2%), and dabigatran (60.8%).

CONCLUSION

Based on the results of this study, VKAs may be the best intervention measure for reducing the risk of cognitive decline in patients with AF. Owing to the limitations of this study, more high-quality randomized controlled trials with large sample sizes and multiple centers are required to provide more evidence.

Trends in oral anticoagulant use - A 10-year retrospective analysis from a general medicine department of a tertiary care hospital in south India

BACKGROUND

The prescribing practice of newer oral anticoagulants (NOACs) has not been adequately studied in the Indian scenario.

AIMS

We aimed to describe the prescribing practices of oral anticoagulants, the patient profile and medical comorbidities among patients admitted in a general medicine unit.

METHODS

In this retrospective study of the 2742 patients prescribed vitamin- K antagonists (VKAs), during the study period, 150 cases were randomly taken for analysis to match the 105 NOACs cases. Their demographic details, clinical characteristics and treatment details were analyzed.

RESULTS

More than 95% of anticoagulants prescribed were VKAs. The prescription of anticoagulants was more common in men (median age 63 years) for prescription of NOACs and 52 years for VKAs. Dabigatran (60.9%) and warfarin (81.3%) were the most prescribed drugs in their respective classes. The most common indication was for cardiovascular diseases with atrial fibrillation (32%). Diabetes and hypertension were the most common comorbidities in patients prescribed oral anticoagulants with a larger proportion of patients with heart failure being prescribed VKAs ( P < 0.01). Patients in the NOACs group had a higher HAS-BLED high-risk score (33.3% vs. 17.3%; P = 0.002). Logistic regression analysis revealed that patients with co-morbidities of congestive heart failure were more likely to be prescribed VKAs while diabetics were more likely to receive NOACs.

CONCLUSIONS

VKAs were the most prescribed anticoagulants; congestive heart failure, diabetes, and hypertension were the commonest comorbidities; and atrial fibrillation was the commonest indication. Patients with a high HAS-BLED score were prescribed NOACs more often.

Dabigatran Dosing Proposal for Adults With Atrial Fibrillation: Stress-Testing Renal Function Range in Real World Patients

Dabigatran is the first of four direct-acting oral anticoagulants approved to prevent stroke in adult patients with atrial fibrillation using a fixed two-dose scheme compared with warfarin dosing adjusted to a prothrombin time range associated with optimal risk reduction in stroke and serious bleeding. The pivotal phase III trial found dabigatran, depending on dose, is superior to warfarin in stroke reduction and similar in bleeding risk while also showing dabigatran efficacy and safety correlate with steady-state plasma concentrations. Because the relationship between dabigatran dose and plasma concentration is highly variable, a previously developed population pharmacokinetic model of over 9,000 clinical trial patients was used as a basis for simulations comparing the performance of dosing via the drug label to other proposed doses and regimens. Assessment of dosing regimen performance was based on simulations of trough plasma levels within the therapeutic concentration range of 75-150 ng/mL over a renal function range of 15-250 mL/min creatinine clearance, representing extremes for real-world patients. An improved regimen that best achieves this therapeutic range was identified, requiring five different dosing schedules, corresponding to specified renal function ranges, compared with the two approved in the label. The discussion focuses on how this information could better inform patient outcomes and future dabigatran development.

Propensity score methods for comparative-effectiveness analysis: A case study of direct oral anticoagulants in the atrial fibrillation population

Objective

To explore methodological challenges when using real-world evidence (RWE) to estimate comparative-effectiveness in the context of Health Technology Assessment of direct oral anticoagulants (DOACs) in Scotland.

Methods

We used linkage data from the Prescribing Information System (PIS), Scottish Morbidity Records (SMR) and mortality records for newly anticoagulated patients to explore methodological challenges in the use of Propensity score (PS) matching, Inverse Probability Weighting (IPW) and covariate adjustment with PS. Model performance was assessed by standardised difference. Clinical outcomes (stroke and major bleeding) and mortality were compared for all DOACs (including apixaban, dabigatran and rivaroxaban) versus warfarin. Patients were followed for 2 years from first oral anticoagulant prescription to first clinical event or death. Censoring was applied for treatment switching or discontinuation.

Results

Overall, a good balance of patients’ covariates was obtained with every PS model tested. IPW was found to be the best performing method in assessing covariate balance when applied to subgroups with relatively large sample sizes (combined-DOACs versus warfarin).

With the IPTW-IPCW approach, the treatment effect tends to be larger, but still in line with the treatment effect estimated using other PS methods. Covariate adjustment with PS in the outcome model performed well when applied to subgroups with smaller sample sizes (dabigatran versus warfarin), as this method does not require further reduction of sample size, and trimming or truncation of extreme weights.

Conclusion

The choice of adequate PS methods may vary according to the characteristics of the data. If assumptions of unobserved confounding hold, multiple approaches should be identified and tested. PS based methods can be implemented using routinely collected linked data, thus supporting Health Technology decision-making.

How lower doses of direct oral anticoagulants are interpreted in clinical practice: a national survey of the Italian Atherosclerosis, Thrombosis and Vascular Biology (ATVB) Study Group

AIM

To evaluate the current interpretation of the lower doses of direct oral anticoagulants (DOAC) dabigatran, apixaban, edoxaban and rivaroxaban in nonvalvular atrial fibrillation.

METHODS

A questionnaire of 14 statements to which the possible answers were fully agree/partially agree/partially disagree/fully disagree or yes/no was prepared within the board of the Italian Atherosclerosis, Thrombosis and Vascular Biology Study Group and forwarded to individual Italian physicians.

RESULTS

A total of 620 complete questionnaires were received from nearly all the Italian regions and physicians of various medical specialists, either enabled or not for the prescription of DOAC. A wide agreement was found as regards the pharmacological, as well as clinical consequences of the administration of the lower dose of factor-Xa inhibitors both in patients with and without clinical and/or laboratory criteria requiring dose reduction. Wide agreement was also found as regards the presence of moderate kidney insufficiency in selecting the dose of DOAC. Instead, more debated were issues regarding the proportionality between dabigatran dose and plasma concentration and selection of dabigatran dose, as well as the role of measuring drug plasma concentration and/or determine the anticoagulant activity of factor-Xa inhibitors when used at the lower dose.

CONCLUSION

The interpretation of the lower doses of DOAC in current Italian clinical practice appears largely correct and shared. Because of the persistence of some residual uncertainties, essentially regarding dabigatran, however, continuous educational effort still appears warranted.

Nonvitamin K Antagonist Oral Anticoagulant in Patients With Venous Thromboembolism and Polycythemia Vera or Essential Thrombocythemia: A Cohort Study

ABSTRACT

Thrombosis is the most common adverse event in patients with polycythemia vera (PV) and essential thrombocythemia (ET). Little is known about the use of nonvitamin K antagonist oral anticoagulants (NOACs) in patients with myeloproliferative neoplasms. We sought to evaluate the efficacy and safety of NOAC in a cohort of patients with PV and ET, who experienced venous thromboembolism (VTE). We enrolled 48 consecutive patients with PV (70.8%) and ET [median age 67.0 (interquartile range, 58.5-72.0) years], who experienced VTE. Patients received apixaban (39.6%), rivaroxaban (33.3%), or dabigatran (27.1%). During a median follow-up of 30 (interquartile range, 20.5-41.5) months, recurrent thrombotic events and bleeding were recorded. Four thrombotic events (3.3 per 100 patient-years) were reported. Three deep vein thrombosis episodes (2.5 per 100 patient-years) were experienced by 2 patients with PV, who received apixaban (5 mg bid) and dabigatran (150 mg bid), and 1 patient with ET, who received dabigatran (150 mg bid). One ischemic stroke occurred in a patient with PV on rivaroxaban (20 mg/d). There was 1 major bleeding (0.8 per 100 patient-years) in a patient with ET on dabigatran (150 mg bid) and 3 clinically relevant nonmajor bleeding (2.5 per 100 patient-years): 2 on rivaroxaban (20 mg/d) and 1 on apixaban (5 mg bid). We did not observe significant differences related to the type of NOAC. Three deaths (2.5 per 100 patient-years) unrelated to either VTE or bleeding were recorded. This study shows that NOACs may be effective and safe as secondary prevention of VTE in patients with myeloproliferative neoplasms.

Personalizing the decision of dabigatran versus warfarin in atrial fibrillation: A secondary analysis of the Randomized Evaluation of Long-term anticoagulation therapY (RE-LY) trial

Background

The RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial demonstrated that higher-risk patients with atrial fibrillation had lower rates of stroke or systemic embolism and a similar rate of major bleeding, on average, when treated with dabigatran 150mg compared to warfarin. Since population-level averages may not apply to individual patients, estimating the heterogeneity of treatment effect can improve application of RE-LY in clinical practice.

Methods and results

For 18040 patients randomized in RE-LY, we used patient-level data to develop multivariable models to predict the risk for stroke or systemic embolism and for major bleeding including all three treatment groups (dabigatran 110mg, dabigatran 150mg, and warfarin) over a median follow up of 2.0 years. The mean predicted absolute risk reduction (ARR) for stroke/systemic embolism with dabigatran 150mg compared to warfarin was 1.32% (range 11.6% lower to 3.30% higher risk). The mean predicted ARR for bleeding was 0.41% (range 8.93% lower to 63.4% higher risk). Patients with increased stroke/systemic embolism risk included those with prior stroke/TIA (OR 2.01), diabetics on warfarin (OR 2.00), and older patients on dabigatran 150mg (OR 1.68 for every 10-year increase). Major bleeding risk was higher in patients on aspirin (OR 1.25), with a history of diabetes (OR 1.34) or prior stroke/TIA (OR 1.22), those with heart failure on dabigatran 110mg (OR 1.52), older patients on either dabigatran 110mg or 150mg (OR 1.57 and 1.93, respectively, for each 10-year increase), and heavier patients on dabigatran 110mg or 150mg; patients in a region outside the United States and Canada and with better renal function had lower bleeding risk.

Conclusions

There is substantial heterogeneity in the benefits and risks of dabigatran relative to warfarin among patients with atrial fibrillation. Using individualized estimates may enable shared decision making and facilitate more appropriate use of dabigatran; as such, it should be prospectively tested.

Clinical trial registration

www.clinicaltrials.gov number, NCT00262600.

Thrombin Inhibition Prevents Endothelial Dysfunction and Reverses 20-HETE Overproduction without Affecting Blood Pressure in Angiotensin II-Induced Hypertension in Mice

Angiotensin II (Ang II) induces hypertension and endothelial dysfunction, but the involvement of thrombin in these responses is not clear. Here, we assessed the effects of the inhibition of thrombin activity by dabigatran on Ang II-induced hypertension and endothelial dysfunction in mice with a particular focus on NO- and 20-HETE-dependent pathways. As expected, dabigatran administration significantly delayed thrombin generation (CAT assay) in Ang II-treated hypertensive mice, and interestingly, it prevented endothelial dysfunction development, but it did not affect elevated blood pressure nor excessive aortic wall thickening. Dabigatran’s effects on endothelial function in Ang II-treated mice were evidenced by improved NO-dependent relaxation in the aorta in response to acetylcholine in vivo (MRI measurements) and increased systemic NO bioavailability (NO₂⁻ quantification) with a concomitant increased ex vivo production of endothelium-derived NO (EPR analysis). Dabigatran treatment also contributed to the reduction in the endothelial expression of pro-inflammatory vWF and ICAM-1. Interestingly, the fall in systemic NO bioavailability in Ang II-treated mice was associated with increased 20-HETE concentration in plasma (UPLC-MS/MS analysis), which was normalised by dabigatran treatment. Taking together, the inhibition of thrombin activity in Ang II-induced hypertension in mice improves the NO-dependent function of vascular endothelium and normalises the 20-HETE-depedent pathway without affecting the blood pressure and vascular remodelling.

Comparison of Low-Dose Direct Acting Anticoagulant and Warfarin in patients Aged ≥80 years With Atrial Fibrillation

Low dose direct acting oral anticoagulants (LDDOACS) were approved for elderly atrial Fibrillation (AF) patients with limited information. A retrospective analysis collecting baseline characteristics and outcomes in AF patients ≥ 80 prescribed LDDOAC or warfarin (W), from a multidisciplinary practice between 1/1/11 (First LDDOAC available) and 5/31/17 was conducted. From 9660 AF patients, 514 ≥ 80 received a LDDOAC and 422 W. A multivariable comparison found LDDOAC patients were older (p <0.001), had lower creatinine clearance (CrCl) (p = 0.006), used more anti-platelet drugs (p <0.001), and more often had new onset AF verses those prescribed W (p <0.001). There were no clinically significant differences among those patients receiving Dabigatran 75 mgs BID (D), Rivaroxaban 15mgs (R) or Apixaban 2.5mgs BID (A). Forty-eight and 50% of the patients remained on their LDDOAC or W for the observation period (p = 0.55). Stroke/systemic embolism (SSE) and CNS bleeds were 1.16 vs 2.22%/yr., (p = 0.143) and 1.46 vs 0.93%/yr., (p = 0.24). Mortality and major bleeds were 6.26 vs 1.67%/yr., and 12.3vs 3.77%/yr. (p <0.001). SSE were 1.1%/yr for D, R, and A (p = 0.94). CNS bleeds were 2.2 for D, 1.7 for R and 0.8%/yr. for A: p = 0.53. Major bleeding was: 14.3 for D, 14.1 for R and 9.1%/yr. for A, p = 0.048 (with A < R, p = 0.01). Mortality was 5.5 for D, 4.2 for R and 9.5% for A, p = 0.031. In conclusion, half the patients remained on their assigned anti-coagulant. SSE and intracranial bleed rates were similar and low. Major bleeds and deaths were different between groups emphasizing the need for prospective randomized trials in this growing population with AF.

Comparative study of adverse drug reactions among direct-acting oral anticoagulants and vitamin K antagonists using the EudraVigilance database

Our aim was to compare adverse drug reactions (ADRs) associated with direct-acting oral anticoagulants and vitamin K antagonists from the European EudraVigilance (EV) database. The EV database is the system for the analysis of information on suspected ADRs that are authorised, or being evaluated in clinical trials, in the European Economic Area. Registered ADRs (from the groups "Gastrointestinal disorders", "General disorders and administration site conditions", "Injury, poisoning and procedural complications", "Nervous system (NS) disorders" and "Vascular disorders") for apixaban, rivaroxaban, dabigatran and vitamin K antagonists (VKA) were collected by age group (< 65 years; 65-85 years and > 85 years) and by sex. The proportional reporting ratio (PRR) was used to compare ADRs in relation to the anticoagulants tested. A total of 274,693 ADRs were analysed. For gastrointestinal ADRs, patients treated with rivaroxaban and dabigatran (PRR 2.17 and 2.51, respectively) were at significantly higher risks than those treated with apixaban and VKA (PRR 1.27 and 1.47, respectively), while risks for vascular disorders were increased by all anticoagulants that were tested. Lastly, none of the anticoagulants significantly increased the risk of ADRs within the NS group. Rivaroxaban and dabigatran were associated with a significantly higher risk of gastrointestinal ADR than apixaban or VKA. All anticoagulants increased the risk of vascular pathology while none of them demonstrated significant increased risk of ADR to NS.

Body Mass Index Influence on the Clinical Outcomes for Nonvalvular Atrial Fibrillation Patients Admitted to a Hospital Treated with Direct Oral Anticoagulants: A Retrospective Cohort Study

BACKGROUND

Considering that the current fixed dose of direct oral anticoagulants (DOACs) might have insufficient anticoagulation effect for overweight patients, the aim of this study was to compare the effectiveness and safety of anticoagulation between dabigatran and rivaroxaban in different body mass index (BMI) population.

METHODS

We conducted a retrospective cohort study of 2402 DOAC anticoagulated patients with atrial fibrillation who underwent catheter ablation (1290 dabigatran, 53.7% and 1112 rivaroxaban, 46.3%) between January 2017 and December 2018. Patients were distributed based on the BMI into nonobese (1362, BMI <25 kg/m2), preobese (521, BMI 25.0-29.9 kg/m2), class I obese (344, BMI 30.0-34.9 kg/m2) and class II+ obese (175, BMI ≥35.0 kg/m2). We collected information regarding clinical features, laboratory data, bleeding complications and systemic embolic events from the electrical medical records system during 12 months.

RESULTS

The incidence of systemic embolism and stroke complications was higher in the class II+ obese group (P=0.001 and P=0.003). The incidence of bleeding complications and the levels of anticoagulation parameters under the bleeding threshold were similar among the four groups (P>0.05). Cumulative Kaplan-Meier analysis illustrated that rivaroxaban-treated patients who belonged to higher BMI subgroups were more likely to experience shorter time to thrombosis (TTT) (12-month TTT rates of 0.5% for nonobese vs 1.7% for class I obese patients, HR=3.716, P=0.005; 12-month TTT rates of 0.5%, for nonobese vs 4.0% for class II+ obese patients, HR=6.843, P=0.001). However, no statistical significant difference in terms of the time to bleeding complications and the time to cumulative events among the four groups was observed. By multivariate analysis, a higher BMI value (BMI ≥25 kg/m2) (P=0.019; OR=2.094, 95%CI: 1.129-3.883) was an independent predictor for thrombosis in patients treated with dabigatran or rivaroxaban. Positive linear relationship was observed between BMI levels and occurrence rate of thrombosis and bleeding in under anticoagulation patients with NVAF (R2=0.451 and R2=0.383, respectively).

CONCLUSION

The fixed dose of 15 mg rivaroxaban might carry a risk of under exposure, which would lead to an increase of thromboembolic complications in patients with high BMI. Therefore, rivaroxaban dose increase was suggested for obese patients. Use of DOACs appears to have considerable safety in obese patients.

[Is one DOAC better than another?]

Real-world evidence is accumulating to support the idea that there are differences among the direct oral anticoagulants (DOACs). The results of the study, discussed elsewhere in the NTvG, add to the growing body of evidence that while there is almost no difference in efficacy in prevention of the thromboembolic complications of non-valvular atrial fibrillation there are significant differences in safety. Apixaban is safer than rivaroxaban, with significantly less major bleeding, any bleeding or gastro-intestinal bleeding. Apixaban is probably the safest DOAC of the four available. These differences between DOACs with almost equal half-life are probably partly due to the differences in dosing interval: twice a day (BID) versus once a day (QD).

Symptomatic bilateral massive pulmonary embolism and proximal and distal deep vein thrombosis following arthroscopic meniscus surgery: A case report

RATIONALE

The incidence of venous thromboembolism (VTE) after knee arthroscopy is remarkably lower than that of arthroplasty. We describe a patient with symptomatic bilateral massive pulmonary thromboembolism (PTE) and deep vein thrombosis (DVT) in the femoral and popliteal veins after arthroscopic meniscus repair surgery.

PATIENT CONCERNS

The patient underwent arthroscopic meniscus repair with no intraoperative complication. There were no underlying diseases such as hypertension or diabetes. On day 5 postoperative, the patient complained of dyspnea, chest discomfort, and nausea after standing.

DIAGNOSIS

On DVT and PTE computed tomography, there were multifocal PTEs in the distal portion of the main and segmental branches of both pulmonary arteries. There was a focal thrombosis in the left deep femoral vein, as well as small DVTs in the left popliteal and calf veins.

INTERVENTIONS

After 3 days of low-molecular-weight heparin 1 mg/kg every 12 hours, treatment was changed to an oral drug, dabigatran, for 6 months.

OUTCOMES

There were no PTE or DVT findings on computed tomography at 6 months postoperative. The patient did not complain of symptoms related to PTE or DVT at 6 months after the operation, has returned to work, and is living without discomfort.

LESSIONS

The frequency of VTE is very low after arthroscopic meniscus surgery, but it represents a life-threatening event. Our patient had risk factors for VTE including obesity, surgery time of ∼60 minutes, and immobilization. Although arthroscopic meniscus surgery is relatively safe, evaluation of risk factors for VTE should be performed before and after surgery, and appropriate thromboprophylaxis should be provided when necessary.

Patient satisfaction with dabigatrean and warfarin for stroke prevention in atrial fibrillation: Taiwan PASSION study

BACKGROUND

Patient satisfaction with oral anticoagulant (OAC) therapy is an important metric of care quality and has been associated with higher medication persistence. Among OACs, dabigatran has been shown to be non-inferior to vitamin K antagonists (VKAs) with increased ease of use for stroke prevention in patients with atrial fibrillation (AF). In this study, we sought to evaluate the expectations, convenience, and satisfaction of Taiwanese AF patients on dabigatran and VKA therapies as well as associated clinical outcomes.

METHODS

Patients with AF (paroxysmal, persistent, or permanent) receiving OAC medication from outpatient facilities were enrolled in 24 hospitals across Taiwan. Cohort A consisted of 139 patients switched from VKA to dabigatran, while cohort B was comprised of 1113 patients on newly initiated OAC therapy (VKA, 54). The Perception of Anticoagulant Treatment Questionnaire was distributed, and responses on a five-point Likert scale were aggregated and analyzed across demographic groups.

RESULTS

In cohort A, convenience and satisfaction scores continued to increase at follow-up and significantly higher, compared to baseline, but both treatments scored similarly in cohort B. In cohort B, the two highest expectation scores were that the OAC would be "easy to take" and could be "taken independently." On the other hand, the patients were relatively less concerned about the side effects and cost of therapy before taking the OAC. For dabigatran-receiving patients, there were 1.1 stroke-related events per 100 patient-years and 3.0 bleeding-related events per 100 patient-years.

CONCLUSION

In Taiwanese patients with AF and initially treated with VKA, switched to dabigatran resulted in higher convenience and treatment satisfaction. For those patients on newly initiated OAC treatment, VKA and dabigatran convenience and satisfaction scores were similar.

Antithrombotic management and outcomes of patients with atrial fibrillation treated with NOACs early at the time of market introduction: Main results from the PREFER in AF Prolongation Registry

The management of patients with atrial fibrillation (AF) has rapidly changed with increasing use of non-vitamin K antagonist oral anticoagulants (NOACs) and changes in the use of rhythm control therapy. The prevention of thromboembolic events European Registry in Atrial Fibrillation Prolongation Registry (PREFER Prolongation) enrolled consecutive patients with AF on NOACs between 2014 and 2016 in a multicentre, prospective, observational study with one-year follow-up, focusing on the time of introduction of NOACs. Overall, 3783 patients were enrolled, with follow-up information available in 3223 (85%). Mean age was 72.2 ± 9.4 years, 40% were women, mean CHA₂DS₂VASc score was 3.4 ± 1.6, and 2587 (88.6%) had a CHA₂DS₂VASc score ≥ 2. Rivaroxaban was used in half of patients, and dabigatran and apixaban were used in about a quarter of patients each; edoxaban was not available for use in Europe at the time. Major cardiovascular event rate was low: serious events occurred in 74 patients (84 events, 2%), including 24 strokes (1%), 62 major bleeds (2%), of which 30 were life-threatening (1%) and 3 intracranial (0.1%), and 28 acute coronary syndromes (1%). Mortality was 2%. Antiarrhythmic drugs were used in about 50% of patients, catheter ablation in 5%. Adverse events were low in this contemporary European cohort of unselected AF patients treated with NOACs already at the time of their first introduction, despite high thromboembolic risk.

An unexpected case of recurrence of pulmonary embolism in a patient recovered from COVID19 in full regimen dose of direct oral anticoagulant drug

BACKGROUND

Coronavirus Disease 2019 (COVID-19) is a pandemic affecting all countries in the world. Italy has been particularly afflicted by the health emergency, and since the peak phase has passed, major concern regarding medium to long term complications due to COVID-19 is arising. Little is known in literature regarding thromboembolic complications once healed after COVID-19.

CASE PRESENTATION

A 51-year-old patient recovered from COVID-19 pneumonia complicated by pulmonary embolism (PE) came to the hospital for palpitations and chest pain. Although he was on treatment dose of direct oral anticoagulation (DOAC), massive recurrent PE was diagnosed.

CONCLUSION

In the early post COVID-19 era, the question remains regarding the efficacy of DOACs in COVID-19 patients.

Comparison of the efficacy of rivaroxaban and dabigatran etexilate in preventing venous thrombosis after arthroplasty: A protocol of randomized controlled trial

Background:

New oral anticoagulants (NOAC) are gradually accepted by clinical practice for its convenient route of administration and stable effect. Both rivaroxaban and dabigatran etexilate have been used in the prevention and treatment of venous embolism after arthroplasty, but there is a lack of direct comparison between the 2 effects. Therefore, the purpose of this randomized controlled trial was to evaluate the efficacy and safety of 2 new oral anticoagulants, rivaroxaban, and dabigatran etexilate, in the prevention of venous thromboembolism after joint replacement.

Methods:

This is a prospective randomized controlled trial to study the efficacy and safety of rivaroxaban and dabigatran etexilate in the prevention of venous thromboembolism after joint replacement, and is approved by the clinical research ethics of our hospital. Patients were randomly divided into 1 of 2 treatment regimens:

Patients, doctors, nurses, and data collection assistants were blinded to group allocation. The indicators of observation include:

Data were analyzed using the statistical software package SPSS version 25.0 (Chicago, IL).

Discussion:

This study will evaluate the efficacy and safety of rivaroxaban and dabigatran etexilate in preventing venous thrombosis after joint replacement. The results of this experiment will provide clinical basis for the use of rivaroxaban or dabigatran etexilate to prevent venous thrombosis after joint replacement.

Ethics and dissemination:

Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval was not required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.

OSF Registration number:

DOI 10.17605/OSF.IO/QVDCW.

The risk of stroke/systemic embolism and major bleeding in Asian patients with non-valvular atrial fibrillation treated with non-vitamin K oral anticoagulants compared to warfarin: Results from a real-world data analysis

BACKGROUND

Although randomized trials provide a high level of evidence regarding the efficacy of non-vitamin K oral anticoagulants (NOACs), the results of such trials may differ from those observed in day-to-day clinical practice.

AIMS

To compare the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between NOAC and warfarin in clinical practice.

METHODS

Patients with non-valvular atrial fibrillation (NVAF) who started warfarin/NOACs between January 2015 and November 2016 were retrospectively identified from Korea's nationwide health insurance claims database. Using inpatient diagnosis and imaging records, the Cox models with inverse probability of treatment weighting using propensity scores were used to estimate hazard ratios (HRs) for NOACs relative to warfarin.

RESULTS

Of the 48,389 patients, 10,548, 11,414, 17,779 and 8,648 were administered apixaban, dabigatran, rivaroxaban and warfarin, respectively. Many patients had suffered prior strokes (36.7%, 37.7%, 31.4%, and 32.2% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), exhibited high CHA2DS2-VASc (4.8, 4.6, 4.6, and 4.1 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) and HAS-BLED (3.7, 3.6, 3.6, and 3.3 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) scores, had received antiplatelet therapy (75.4%, 75.7%, 76.8%, and 70.1% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), or were administered reduced doses of NOACs (49.8%, 52.9%, and 42.8% in apixaban, dabigatran, and rivaroxaban group, respectively). Apixaban, dabigatran and rivaroxaban showed a significantly lower S/SE risk [HR, 95% confidence intervals (CI): 0.62, 0.54-0.71; 0.60, 0.53-0.69; and 0.71, 0.56-0.88, respectively] than warfarin. Apixaban and dabigatran (HR, 95% CI: 0.58, 0.51-0.66 and 0.75, 0.60-0.95, respectively), but not rivaroxaban (HR, 95% CI: 0.84, 0.69-1.04), showed a significantly lower MB risk than warfarin.

CONCLUSIONS

Among Asian patients who were associated with higher bleeding risk, low adherence, and receiving reduced NOAC dose than that provided in randomised controlled trials, all NOACs were associated with a significantly lower S/SE risk and apixaban and dabigatran with a significantly lower MB risk than warfarin.

Non-Vitamin K Antagonist Oral Anticoagulants in Secondary Stroke Prevention in Atrial Fibrillation Patients: An Updated Analysis by Adding Observational Studies

BACKGROUND

This meta-analysis aimed to evaluate the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) versus vitamin K antagonists (VKAs) in secondary stroke prevention in atrial fibrillation (AF) patients.

METHODS

PubMed and Embase electronic databases were systematically searched from January 2009 to July 2019 for relevant randomized clinical trials and observational studies. A random-effects model was applied in the pooled analysis.

RESULTS

A total of 14 studies (4 randomized clinical trials and 10 observational studies) were included. Based on the randomized clinical trials, compared with VKA use, the use of NOACs was associated with decreased risk of stroke and systemic embolism, major bleeding, and intracranial bleeding. Based on the observational studies, compared with VKAs, the subgroup analysis showed that dabigatran and rivaroxaban were associated with a reduced risk of stroke or systemic embolism, whereas dabigatran and apixaban were associated with a decreased risk of major bleeding.

CONCLUSION

Based on current data, the use of NOACs is at least non-inferior to the use of VKAs in AF patients for secondary stroke prevention irrespective of NOAC type.

Non-Vitamin K Antagonist Oral Anticoagulants and Factors Influencing the Ischemic and Bleeding Risk in Elderly Patients With Atrial Fibrillation: A Review of Current Evidence

ABSTRACT

Non-vitamin K antagonist oral anticoagulants (NOACs) are a widely prescribed treatment to prevent stroke in patients with nonvalvular atrial fibrillation, and a therapy and preventative measure to prevent recurrences following venous thromboembolism. Optimal use of NOACs requires a thorough knowledge of the pharmacology of these drugs, as well as an understanding of patient factors affecting their use. The 4 NOACs-dabigatran, apixaban, edoxaban, and rivaroxaban are available in a range of doses suitable for differing indications and with a variety of dose reduction criteria. Identification of the correct dose is one of the key challenges in the individualization of treatment. Elderly patients with atrial fibrillation are at a greater risk of both ischemic and bleeding events than younger patients. Consequently, it is essential to achieve balance in anticoagulation strategies. Medication adherence to NOACs is important for safe and effective treatment, particularly in elderly populations. A growing body of evidence shows that once-daily dosing improves adherence and persistence to therapy, without having an impact on bleeding risk.

Left atrial appendage thrombus formation in a patient with atrial fibrillation on dabigatran therapy associated with CES1 and ABCB1 genetic polymorphisms: A case report

RATIONALE

Dabigatran is a direct thrombin inhibitor that is widely used to prevent the formation of thrombus formation. Amiodarone can increase the plasma concentration of dabigatran. CES1 (carboxylesterase 1) and ABCB1 (ATP-binding cassette subfamily B member 1) genetic polymorphisms associate with the pharmacokinetics of dabigatran.

PATIENT CONCERNS

A 62-year-old woman was admitted to the hospital due to chest tightness, fatigue, and discomfort despite long-term anticoagulation with dabigatran 110 mg twice daily for 6 months, with concomitant use of amiodarone.

DIAGNOSES

Left atrial appendage thrombus formation with a history of atrial fibrillation.

INTERVENTIONS

The clinician changed dabigatran to warfarin. To explore the causes of insufficient anticoagulation using dabigatran in this patient, we examined the ABCB1 and CES1 genes. Results showed that she carried ABCB1 variant alleles with 3 heterozygote single nucleotide polymorphisms (SNPs: rs4148738, rs1045642, rs2032582) and CES1 variant alleles with 2 heterozygote SNPs (rs2244613, rs4580160).

OUTCOMES

The left atrial appendage thrombus disappeared.

LESSONS

Multiple mutations in the ABCB1 and CES1 genes may influence the pharmacokinetics of dabigatran and could have contributed to the thrombus formation in the left atrial appendage.

A Structured Literature Review and International Consensus Validation of FORTA Labels of Oral Anticoagulants for Long-Term Treatment of Atrial Fibrillation in Older Patients (OAC-FORTA 2019)

INTRODUCTION

Evidence regarding safety and efficacy of oral anticoagulants for the treatment of atrial fibrillation (AFib) in older adults has been assessed regarding the age appropriateness of oral anticoagulants (OAC) according to the FORTA (Fit fOR The Aged) classification (OAC-FORTA). Three years after its first version (OAC-FORTA 2016), an update was initiated to create OAC-FORTA 2019.

METHODS

A structured review of randomized controlled clinical trials and summaries of individual product characteristics was performed to detect newly emerged evidence on oral anticoagulants in older patients with AFib. This review was used by an interdisciplinary panel of European experts (N = 10) in a Delphi process to label OACs according to FORTA.

RESULTS

A total of 202 records were identified and 11 studies finally included. We found four new trials providing relevant data on efficacy and safety of warfarin, apixaban, dabigatran or rivaroxaban in older patients with AFib. In the majority of studies comparing the non-vitamin-K oral anticoagulants (NOACs) with warfarin, NOACs were superior to warfarin regarding at least one relevant clinical endpoint. The mean consensus coefficient significantly increased from 0.867 (OAC-FORTA 2016) to 0.931 (p < 0.05) and the proposed FORTA classes were confirmed in all cases during the first round (consensus coefficient > 0.8). Warfarin, dabigatran, edoxaban and rivaroxaban were assigned to the FORTA B label, acenocoumarol, fluindione and phenprocoumon were labeled FORTA C and only apixaban was rated as FORTA A.

CONCLUSION

OAC-FORTA 2019 confirms that AFib can be successfully treated with positively labeled antithrombotics at advanced age.

Does the CHA2DS2-VASc scale sufficiently predict the risk of left atrial appendage thrombus in patients with diagnosed atrial fibrillation treated with non-vitamin K oral anticoagulants?

The CHA2DS2-VASc scale does not include potential risk factors for left atrial appendage thrombus (LAAT) formation such as a form of atrial fibrillation (AF) and impaired kidney function. The real risk of thromboembolic complications in AF patients is still unclear as well as an optimal anticoagulant treatment in males with a CHA2DS2-VASc score of 1 and females with a CHA2DS2-VASc score of 2.The aim of this study was to compare the predictive value of the CHA2DS2-VASc scale and other scales to estimate the risk of LAAT formation in AF patients treated with non-vitamin K oral anticoagulants (NOACs) and to assess the prevalence of thrombi in patients at intermediate risk of stroke.The observational study included consecutive patients with a diagnosis of non-valvular AF treated with NOACs, admitted to 3 high-reference institutions between 2013 and 2018. All individuals underwent transoesophageal echocardiography before cardioversion or ablation.Out of 1163 enrolled AF patients (62.1% male, mean age 62 years) the LAAT had been detected in 50 individuals (4.3%). Among patients with LAAT, 1 patient (2.0%) was classified as a low-risk category, 9 (18.0%) were at intermediate-risk, and 40 (80.0%) were at high risk of thromboembolic complications according to CHA2DS2-VASc scale. All patients were treated with NOACs: 51.0% rivaroxaban, 47.1% dabigatran, and 1.9% apixaban.Patients at intermediate stroke-risk with detected LAAT had higher R2CHADS2 score (2.1 ± 1.2 vs 1.2 ± 0.8, P = .007), higher CHA2DS2-VASc-RAF score (6.4 ± 4.4 vs 3.7 ± 2.6, P = .027) and more often had an estimated glomerular filtration rate below 56 mL/min/1.73 m (44.4% vs 13.2%, P = .026) compared to patients without LAAT. The receiver operating characteristics revealed that the CHA2DS2-VASc-RAF scale had better predictive ability to distinguish between patients with and without LAAT in the study group than CHA2DS2-VASc (P = .0006), CHADS2 (P = .0006) and R2CHADS2 scale (P = .0140).The CHA2DS2-VASc scale should be supplemented with an assessment of renal function and form of AF to improve stroke risk estimation. The application of additional scales to estimate the risk of LAAT might be especially useful among males with a CHA2DS2-VASc score of 1 and females with a CHA2DS2-VASc score of 2.

Antithrombotic Treatment of Embolic Stroke of Undetermined Source: RE-SPECT ESUS Elderly and Renally Impaired Subgroups

Background and Purpose- The RE-SPECT ESUS trial (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) tested the hypothesis that dabigatran would be superior to aspirin for the prevention of recurrent stroke in patients with embolic stroke of undetermined source. This exploratory subgroup analysis investigates the impact of age, renal function (both predefined), and dabigatran dose (post hoc) on the rates of recurrent stroke and major bleeding. Methods- RE-SPECT ESUS was a multicenter, randomized, double-blind trial of dabigatran 150 or 110 mg (for patients aged ≥75 years and/or with creatinine clearance 30 to <50 mL/minute) twice daily compared with aspirin 100 mg once daily. The primary outcome was recurrent stroke. Results- The trial, which enrolled 5390 patients from December 2014 to January 2018, did not demonstrate superiority of dabigatran versus aspirin for prevention of recurrent stroke in patients with embolic stroke of undetermined source. However, among the population qualifying for the lower dabigatran dose, the rate of recurrent stroke was reduced with dabigatran versus aspirin (7.4% versus 13.0%; hazard ratio, 0.57 [95% CI, 0.39-0.82]; interaction P=0.01). This was driven mainly by the subgroup aged ≥75 years (7.8% versus 12.4%; hazard ratio, 0.63 [95% CI, 0.43-0.94]; interaction P=0.10). Stroke rates tended to be lower with dabigatran versus aspirin with declining renal function. Risks for major bleeding were similar between treatments, irrespective of renal function, but with a trend for lower bleeding rates with dabigatran versus aspirin in older patients. Conclusions- In subgroup analyses of RE-SPECT ESUS, dabigatran reduced the rate of recurrent stroke compared with aspirin in patients qualifying for the lower dose of dabigatran. These results are hypothesis-generating. Aspirin remains the standard antithrombotic treatment for patients with embolic stroke of undetermined source. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120.

Direct oral anticoagulant plasma levels' striking increase in severe COVID-19 respiratory syndrome patients treated with antiviral agents: The Cremona experience

BACKGROUND

Antiviral drugs are administered in patients with severe COVID-19 respiratory syndrome, including those treated with direct oral anticoagulants (DOACs). Concomitant administration of antiviral agents has the potential to increase their plasma concentration. A series of patients managed in the Cremona Thrombosis Center were admitted at Cremona Hospital for SARS-CoV-2 and started antiviral drugs without stopping DOAC therapy. DOAC plasma levels were measured in hospital and results compared with those recorded before hospitalization.

METHODS

All consecutive patients on DOACs were candidates for administration of antiviral agents (lopinavir, ritonavir, or darunavir). Plasma samples for DOAC measurement were collected 2to 4 days after starting antiviral treatment, at 12 hours from the last dose intake in patients on dabigatran and apixaban, and at 24 hours in those on rivaroxaban and edoxaban. For each patient, C-trough DOAC level, expressed as ng/mL, was compared with the one measured before hospitalization.

RESULTS

Of the 1039 patients hospitalized between February 22 and March 15, 2020 with COVID-19 pneumonia and candidates for antiviral therapy, 32 were on treatment with a DOAC. DOAC was stopped in 20 and continued in the remaining 12. On average, C-trough levels were 6.14 times higher during hospitalization than in the pre-hospitalization period.

CONCLUSION

DOAC patients treated with antiviral drugs show an alarming increase in DOAC plasma levels. In order to prevent bleeding complications, we believe that physicians should consider withholding DOACs from patients with SARS-CoV-2 and replacing them with alternative parenteral antithrombotic strategies for as long as antiviral agents are deemed necessary and until discharge.

Effects of dabigatran and fondaparinux on degloving injuries: An experimental study

BACKGROUND

Management of the skin degloving injuries is still a problematic issue, and the avulsed part of the skin may become necrotic. We hypothesized that the anticoagulant pharmacological agents, fondaparinux and dabigatran may be beneficial in the treatment of degloving injuries by enhancing the viability of the reattached flap.

METHODS

Twenty four Wistar rats were divided into three groups as follows: control group (Group 1), fondaparinux group (Group 2) and dabigatran group (Group 3). A model of a degloving injury on the tail of rats was developed in all groups. After 15 minutes, the avulsed flaps were sutured back. Group 1 received 1ml/day saline intraperitoneally for 10 days. Group 2 received 0.3 ml/kg/day fondaparinux intraperitoneally for 10 days. Group 3 received 30 mg/kg/day dabigatran orally for 10 days. At the end of the treatments, gross morphological and histopathological tail tissue survivals were evaluated.

RESULTS

Histopathological examination of the fondaparinux and dabigatran groups revealed that the tail skin was mostly viable with mild inflammation. The mean necrotic length in tails and severity of inflammation was significantly higher in the control group compared to the fondaparinux and dabigatran groups (p<0.05). No statistically significant differences were noted between the fondaparinux and dabigatran groups in histopathologic evaluations. There was no significant difference in necrosis lengths and the other histopathological parameters between dabigatran and fondaparinux groups.

CONCLUSION

Dabigatran and fondaparinux improved tissue survival in skin degloving injuries concerning gross morphological and histopathological findings. However, the findings of this study should be supported and improved by new experimental and especially clinical studies.

Detecting direct oral anticoagulants in trauma patients using liquid chromatography-mass spectrometry: A novel approach to medication reconciliation

BACKGROUND

Accurate medication reconciliation in trauma patients is essential but difficult. Currently, there is no established clinical method of detecting direct oral anticoagulants (DOACs) in trauma patients. We hypothesized that a liquid chromatography-mass spectrometry (LCMS)-based assay can be used to accurately detect DOACs in trauma patients upon hospital arrival.

METHODS

Plasma samples were collected from 356 patients who provided informed consent including 10 healthy controls, 19 known positive or negative controls, and 327 trauma patients older than 65 years who were evaluated at our large, urban level 1 trauma center. The assay methodology was developed in healthy and known controls to detect apixaban, rivaroxaban, and dabigatran using LCMS and then applied to 327 samples from trauma patients. Standard medication reconciliation processes in the electronic medical record documenting DOAC usage were compared with LCMS results to determine overall accuracy, sensitivity, specificity, and positive and negative predictive values (PPV, NPV) of the assay.

RESULTS

Of 356 patients, 39 (10.96%) were on DOACs: 21 were on apixaban, 14 on rivaroxaban, and 4 on dabigatran. The overall accuracy of the assay for detecting any DOAC was 98.60%, with a sensitivity of 94.87% and specificity of 99.05% (PPV, 92.50%; NPV, 99.37%). The assay detected apixaban with a sensitivity of 90.48% and specificity of 99.10% (PPV, 86.36%; NPV 99.40%). There were three false-positive results and two false-negative LCMS results for apixaban. Dabigatran and rivaroxaban were detected with 100% sensitivity and specificity.

CONCLUSION

This LCMS-based assay was highly accurate in detecting DOACs in trauma patients. Further studies need to confirm the clinical efficacy of this LCMS assay and its value for medication reconciliation in trauma patients.

LEVEL OF EVIDENCE

Diagnostic Test, level III.

Effect of CES1 and ABCB1 genotypes on the pharmacokinetics and clinical outcomes of dabigatran etexilate in patients with atrial fibrillation and chronic kidney disease

Background Despite the well-studied safety profile of dabigatran, its interactions with genetic polymorphism parameters are poorly understood, especially in patients with moderate chronic kidney disease (CKD). The study assessed whether genetic factors can contribute to CKD and alter dabigatran concentration. Methods Patients with atrial fibrillation (AF) and stage 3 CKD treated with dabigatran 110 or 150 mg have been included in the study. Real-time polymerase chain reaction was used to evaluate single-nucleotide polymorphisms of the ABCB1 gene (rs1045642 and rs4148738) and CES1 gene (rs2244613). A plasma trough concentration/dose (C/D) ratio was used as a pharmacokinetic index. Results A total of 96 patients aged 51-89 years (median age: 75 years) were evaluated. Patients on a reduced regimen of 110 mg twice a day were older (79.8 vs. 67.9, p < 0.0001) and had lower creatinine clearance (49.7 vs. 62.3 mL/min/1.73 m2, p = 0.015). Patients with the rs2244613 CC genotype had lower C/D values (70% reduction in the mean C/D vs. AA genotype, p = 0.001). Linear stepwise regression has shown the CKD epidemiology collaboration to be the only significant predictor of C/D among genetic factors and kidney function characteristics. During the median follow-up of 15 months, there were 15 bleedings in 13 patients. Conclusions Polymorphism of CES1 rs2244613 can contribute to the safety of dabigatran in patients with AF and CKD. There was no influence of the aforementioned polymorphisms of ABCB1 on dabigatran trough plasma concentrations and C/D. Kidney function is a mainstay of clinical decision-making on direct oral anticoagulant (DOAC) dose, and further knowledge should be accumulated on the role of genetic factors.

The contribution of real-world evidence to cost-effectiveness analysis: case study of Dabigatran etexilate in France

OBJECTIVE

The goal of this study was to assess the differences between an ex ante and an ex post cost-effectiveness analysis of Dabigatran etexilate vs VKAs for the prevention of thromboembolic events in non-valvular atrial fibrillation patients and to draw lessons on the design and use of real-world data for decision making.

METHODS

The same model was used to calculate the cost-effectiveness ratio using two sets of parameters. One set included the efficacy and safety outcomes data from RE-LY, the pivotal trial comparing Dabigatran to warfarin; cost data came from an ex ante publication. Outcomes data for the second set came from real-world data studies. Cost data were a mix of real-world data and other sources. Two treatment strategies were compared: treatment initiation by either Dabigatran or VKAs, followed by either VKAs or Dabigatran. A crude comparison of results was performed; the impact of data differences was then assessed. Probabilistic sensitivity results of the two analyses were compared.

RESULTS

With real-world evidence, Dabigatran at both dosages was more effective for the prevention of ischemic strokes, intra-cranial haemorrhages, with less major extra-cranial haemorrhages and a similar risk of myocardial infarction. Using clinical trial data, Dabigatran150 mg (resp. Dabigatran110 mg) as a first-line treatment vs VKAs yielded an ICER of € 8077/QALY (resp. € 13,116/QALY). Real-world evidence scenarios were cost-saving and more effective for both dosages.

CONCLUSION

The reassessment of outcomes and cost data had an impact on results, improving the efficiency of Dabigatran. We identify methodological issues which should be discussed if post-launch RWE based cost-effectiveness data become a standard in HTA decision making.

[Peculiarities of the treatment of venous thromboembolism with direct oral anticoagulants in challenging patients: senile age, renal failure, fragility]

The paper is a narrative review of the literature on the use of direct oral anticoagulants (DOACs) for the VTE treatment in challenging patients: senile age (≥75 years), impaired renal function (estimated glomerular filtration rate ≤50 ml/min), fragility (one of the previous characteristics and/or bodyweight ≤50 kg). The paper discusses the studies of EINSTEIN DVT and PE (rivaroxaban), AMPLIFY (apixaban), HOKUSAI-VTE (edoxaban), RE-COVER I and II (dabigatran) in the focus of the secondary analysis in the pre-specified patient's subgroups, as well as their pooled analyzes and meta-analyzes. Based on the results of this review, it was concluded that in a subgroup of senile age patients, dabigatran increases the risk of major bleeding by 4.8 times and has no advantages over vitamin K antagonists (VKA); rivaroxaban and apixaban retain superiority over VKA on the safety outcomes and reduce the risk of major bleeding by 73% and 77%. In the subgroup of patients with impaired renal function, the use of apixaban and dabigatran is associated with an increase in the risk of major bleeding by 6.5 and 7.3 times, and these DOACs do not have advantages over VKA; rivaroxaban retains its superiority over VKA and reduces the risk of major bleeding by 78%. For fragile patients, a secondary analysis is available only for rivaroxaban, which remains superior to VKA on safety endpoints and reduces the risk of major bleeding by 73%. In the absence of direct comparisons between the available DOACs, the presented data can be used as a rational approach for the choice of appropriate treatment for VTE in challenging patients.

[Pharmaco-utilization and outcomes in patients treated with oral anticoagulants from 2014 to 2015: evidences from administrative databases of the Romagna Local Health Unit]

BACKGROUND

The present study aimed at describing (i) the characteristics of non-valvular atrial fibrillation (NVAF) patients newly treated with oral anticoagulants (vitamin K antagonists [VKA] or new oral anticoagulants [NOAC]), and (ii) their persistence to treatment assigned, clinical outcomes (bleeding and thromboembolic events) and mortality.

METHODS

This study was conducted using administrative databases of an Italian Local Health Unit. All adult patients (aged ≥18 years) with NVAF and naïve to VKA (warfarin) or NOAC (rivaroxaban, apixaban, dabigatran) were included between January 1, 2014 and June 30, 2015. Propensity score matching was performed to check for confounding effects. Included patients were characterized for comorbidities, CHA2DS2-VASc and HAS-BLED score, antiplatelet drug use and followed up for at least 12 months to assess persistence to treatment and incidence of clinical outcomes.

RESULTS

A total of 970 NVAF patients newly treated with oral anticoagulants were included; 595 (61.3%) received VKA and 375 (38.7%) NOAC. VKA naïve patients had a lower low and intermediate score for HAS-BLED and CHA2DS2-VASc compared to NOAC patients. Overall, 80.6% of naïve NAO patients and 73.4% of naïve AVK patients were persistent to treatment. Incidence of bleeding events was slightly higher in VKA patients (3.13/100 persons year) compared to NOAC patients (2.73/100 persons years), as well as incidence of thromboembolic events (3.48/100 persons year and 2.18/100 persons year, respectively). After propensity score matching no differences were observed.

CONCLUSIONS

The majority of NVAF patients newly treated with oral anticoagulants received VKA-based therapy. Incidence of bleeding and thromboembolic events was slightly higher in VKA patients compared to NOAC patients.

[Oral anticoagulation in patients with atrial fibrillation and stage 4 or 5 chronic kidney disease]

Patients with chronic kidney disease (CKD) have a high prevalence of atrial fibrillation (AF). Stroke in patients with CKD and AF is frequent, and is usually more severe than in the absence of CKD. Current European Society of Cardiology guidelines recommend oral anticoagulant therapy in order to reduce thromboembolic risk in AF patients in general, and also in the presence of CKD, excluding however stage 4 and dialysis (stage 5) patients. Warfarin and other vitamin K antagonists are still the most frequently used drugs in these settings, despite the high bleeding risk. In the United States, the non-vitamin K antagonist oral anticoagulants, especially apixaban, are here used off-label, despite the absence of strong evidences of efficacy and safety. Several clinical trials are ongoing, and further evidence is needed before non-vitamin K antagonists can be recommended in these patients.

Real-life behaviour of direct oral anticoagulants in a Spanish cohort with non-valvular atrial fibrillation: Refase Registry

Aim: To analyse the effectiveness and safety of DOAC (direct oral anticoagulants) in non-valvular atrial fibrillation (NVAF) patients attending clinical practice.Methods: Retrospective study of AF patients who started treatment with DOAC from January 1, 2013 to December 31, 2016 in three Spanish hospitals. Mean follow-up was 1.6 years. The primary outcomes were rates of all-cause death, ischaemic stroke, and bleeding. These outcomes were also studied depending on correct dosage adjustment and standard/adjusted dose.Results: The study included 2494 patients (age = 76.0 ± 9.5 years, CHA₂DS₂-VASc = 4.0 ± 1.6). The most prescribed DOAC was rivaroxaban (41.1%). Patients taking dabigatran were the youngest (mean age = 73.1 ± 10.3 years), with better kidney function (mean CrCl = 80.6 ± 35.8 ml/min) and lower CHA₂DS₂-VASc (3.7 ± 1.4) and HAS-BLED (2.1 ± 0.9) scores. Patients taking apixaban were the oldest, and had the highest CHA2DS2-VASc and HAS-BLED scores (4.3 ± 1.6 and 2.6 ± 0.9, respectively). Rates of stroke/major bleeding/intracranial bleeding were 1.8/3.0/0.3 events per 100 patient-years, respectively, with no differences among DOAC. Based on dose adjustment according to technical data, it was observed that 517 patients (23.5%) received DOAC doses inconsistent with labelling (p < .001) and, within this group, under-dosed patients had a higher death rate although it did not reach a significant result after multivariate adjustment.Conclusions: The results of safety and efficacy are very similar to those of other previously published national registries. There were no differences among the different types of DOAC regarding outcomes. However, it was found that people taking the adjusted dose of the drug seemed to have a higher risk of death. A non-negligible proportion of patients received DOAC doses inconsistent with labelling (mostly underdose).

A national audit on the utilisation and documentation of dabigatran checklist for patients initiated on dabigatran

BACKGROUND

Direct oral anticoagulants (DOACs) especially dabigatran, have gain popularity for their efficacy, fixed dosing and favourable safety profile. A dabigatran prescribing checklist has been prepared by the Ministry of Health, Malaysia (MOH) to ensure rational and safe prescribing of dabigatran. This study therefore aimed to audit the utilization and documentation of this checklist and use of dabigatran in the government healthcare facilities.

METHODS

This is a nationwide retrospective audit on the documentation of Dabigatran Prescribing and Dispensing Checklist for a period of two years from January 2013 till December 2014. Data from these Dabigatran Checklists (indication, dose, duration, renal function and adverse drug reactions encountered) were extracted by the pharmacist at MOH healthcare facilities.

RESULTS

A total of 52 out of 56 (92.9%) of MOH facilities complied to usage of checklist at their centres involving a total of 582 patients of which 569 (97.7%) patients were initiated on dabigatran for the approved indications. The recommended dose of dabigatran was used correctly in 501 (99.6%) of patients. Reason for switching to DOACs use was only documented in 76.7% (131/171) of patients. The most common reason for switching from warfarin was poor INR control (n=39), history of bleeding/overwarfarinisation (n=22) and unable to attend regular INR clinic (n=21). There were 75 cases of adverse events reported. The most common adverse event reported were abdominal discomfort (n=10) followed by gum bleeding (n=9) and dizziness (n=5).

CONCLUSIONS

Compliance to the dabigatran check list was high with 70% of patients prescribed the appropriate dosing.

Direct oral anticoagulant- versus vitamin K antagonist-related gastrointestinal bleeding: Insights from a nationwide cohort

BACKGROUND

The purpose of the study was to examine the association between the type of preceding oral anticoagulant use (warfarin or direct oral anticoagulants [DOACs]) and in-hospital mortality among patients admitted with gastrointestinal bleeding.

METHODS

In this observational cohort study, all patients admitted with a first-time gastrointestinal bleeding from January 2011 to March 2017 while receiving any oral anticoagulant therapy prior to admission were identified using data from Danish nationwide registries. The risk of in-hospital mortality according to type of oral anticoagulation therapy was examined by multivariable logistic regression models.

RESULTS

Among 5,774 patients admitted with gastrointestinal bleeding (median age, 78 years [25th-75th percentile, 71-85 years]; 56.8% men), 2,038 (35.3%) were receiving DOACs and 3,736 (64.7%) were receiving warfarin prior to admission. The unadjusted in-hospital mortality rates were 7.5% for DOAC (7.2% for dabigatran, 6.4% for rivaroxaban, and 10.1% for apixaban) and 6.5% for warfarin. After adjustment for baseline demographic and clinical characteristics, there was no statistically significant difference in in-hospital mortality between prior use of any DOAC and warfarin (unadjusted odds ratio [OR] 1.18 [95% CI 0.95-1.45], adjusted OR 0.97 [95% CI 0.77-1.24]). Similar results were found for each individual DOAC as compared with warfarin (dabigatran: unadjusted OR 1.12 [95% CI 0.84-1.49], adjusted OR 0.96 [95% CI 0.71-1.30]); rivaroxaban: unadjusted OR 0.98 [95% CI 0.71-1.37], adjusted OR 0.84 [95% CI 0.59-1.21]; and apixaban: unadjusted OR 1.62 [95% CI 0.84-1.49], adjusted OR 1.22 [95% CI 0.83-1.79]).

CONCLUSIONS

Among patients admitted with gastrointestinal bleeding, there was no statistically significant difference in in-hospital mortality between prior use of DOAC and warfarin.

Appropriateness of initial dose of non-vitamin K antagonist oral anticoagulants in patients with non-valvular atrial fibrillation in the UK

OBJECTIVE

To evaluate the appropriateness of the initial prescribed daily dose of non-vitamin K antagonist oral anticoagulants (NOACs) according to label in patients with non-valvular atrial fibrillation (NVAF) in the UK.

DESIGN

Population-based cross-sectional study.

SETTING

UK primary care.

POPULATION

30 467 patients with NVAF and a first prescription for apixaban, dabigatran or rivaroxaban between January 2011 and December 2016.

MAIN OUTCOME MEASURES

Percentage of patients prescribed a NOAC dose according to the European Union (EU) labels (appropriately dosed), and not according to the EU labels (inappropriately dosed-including both underdosed and overdosed patients); percentage of patients prescribed an initial NOAC dose according to renal function status.

RESULTS

A total of 15 252 (50.1%) patients started NOAC therapy on rivaroxaban, 10 834 (35.6%) on apixaban and 4381 (14.4%) on dabigatran. Among patients starting NOAC therapy on rivaroxaban, 17.3% were eligible to receive a reduced dose compared with 12.8% of patients starting on apixaban and 53.8% of patients starting on dabigatran. The majority of patients were prescribed an appropriate dose according to the EU labels: apixaban 74.9 %, dabigatran, 74.4%; rivaroxaban, 84.2%. Underdosing occurred in 21.6% (apixaban), 8.7% (dabigatran), 9.1% (rivaroxaban). Overdosing was more frequent for dabigatran (16.9%) than for rivaroxaban (6.6%) or apixaban (3.5%). There was a trend towards dose reduction with increasing renal impairment. Among patients with severe renal impairment, the majority received a reduced dose NOAC: apixaban, 91.1%, dabigatran, 80.0%, rivaroxaban, 83.0%.

CONCLUSION

Between 2011 and 2016, the majority of patients starting NOAC therapy in UK primary care were prescribed a daily dose in line with the approved EU drug label. Underdosing was more than twice as common among patients starting on apixaban than those starting on dabigatran or rivaroxaban. Research into the patient characteristics that may influence inappropriate underdosing of NOACs in UK primary care is warranted.

Effectiveness and safety of direct oral anticoagulants compared to warfarin in treatment naïve non-valvular atrial fibrillation patients in the US Department of defense population

BACKGROUND

Clinical trials have demonstrated that direct oral anticoagulants (DOACs) are at least non-inferior to warfarin in reducing the risk of stroke/systemic embolism (SE) among patients with non-valvular atrial fibrillation (NVAF), but the comparative risk of major bleeding varies between DOACs and warfarin. Using US Department of Defense (DOD) data, this study compared the risk of stroke/SE and major bleeding for DOACs relative to warfarin.

METHODS

Adult patients with ≥1 pharmacy claim for apixaban, dabigatran, rivaroxaban, or warfarin from 01 Jan 2013-30 Sep 2015 were selected. Patients were required to have ≥1 medical claim for atrial fibrillation during the 12-month baseline period. Patients with a warfarin or DOAC claim during the 12-month baseline period were excluded. Each DOAC cohort was matched to the warfarin cohort using propensity score matching (PSM). Cox proportional hazards models were conducted to evaluate the risk of stroke/SE and major bleeding of each DOAC vs warfarin.

RESULTS

Of 41,001 identified patients, there were 3691 dabigatran-warfarin, 8226 rivaroxaban-warfarin, and 7607 apixaban-warfarin matched patient pairs. Apixaban was the only DOAC found to be associated with a significantly lower risk of stroke/SE (hazard ratio [HR]: 0.55; 95% confidence interval [CI]: 0.39, 0.77; p < 0.001) and major bleeding (HR: 0.65; 95% CI: 0.53, 0.80; p < 0.001) compared to warfarin. Dabigatran and rivaroxaban initiation were associated with similar risk of stroke/SE (dabigatran: HR: 0.68; 95% CI: 0.43, 1.07; p = 0.096; rivaroxaban: HR: 0.83; 95% CI: 0.64, 1.09; p = 0.187) and major bleeding (dabigatran: HR: 1.05; 95% CI: 0.79, 1.40; p = 0.730; rivaroxaban: HR: 1.07; 95% CI: 0.91, 1.27; p = 0.423) compared to warfarin.

CONCLUSION

Among NVAF patients in the US DOD population, apixaban was associated with significantly lower risk of stroke/SE and major bleeding compared to warfarin. Dabigatran and rivaroxaban were associated with similar risk of stroke/SE and major bleeding compared to warfarin.

Dabigatran for Prevention of Stroke after Embolic Stroke of Undetermined Source

BACKGROUND

Cryptogenic strokes constitute 20 to 30% of ischemic strokes, and most cryptogenic strokes are considered to be embolic and of undetermined source. An earlier randomized trial showed that rivaroxaban is no more effective than aspirin in preventing recurrent stroke after a presumed embolic stroke from an undetermined source. Whether dabigatran would be effective in preventing recurrent strokes after this type of stroke was unclear.

METHODS

We conducted a multicenter, randomized, double-blind trial of dabigatran at a dose of 150 mg or 110 mg twice daily as compared with aspirin at a dose of 100 mg once daily in patients who had had an embolic stroke of undetermined source. The primary outcome was recurrent stroke. The primary safety outcome was major bleeding.

RESULTS

A total of 5390 patients were enrolled at 564 sites and were randomly assigned to receive dabigatran (2695 patients) or aspirin (2695 patients). During a median follow-up of 19 months, recurrent strokes occurred in 177 patients (6.6%) in the dabigatran group (4.1% per year) and in 207 patients (7.7%) in the aspirin group (4.8% per year) (hazard ratio, 0.85; 95% confidence interval [CI], 0.69 to 1.03; P = 0.10). Ischemic strokes occurred in 172 patients (4.0% per year) and 203 patients (4.7% per year), respectively (hazard ratio, 0.84; 95% CI, 0.68 to 1.03). Major bleeding occurred in 77 patients (1.7% per year) in the dabigatran group and in 64 patients (1.4% per year) in the aspirin group (hazard ratio, 1.19; 95% CI, 0.85 to 1.66). Clinically relevant nonmajor bleeding occurred in 70 patients (1.6% per year) and 41 patients (0.9% per year), respectively.

CONCLUSIONS

In patients with a recent history of embolic stroke of undetermined source, dabigatran was not superior to aspirin in preventing recurrent stroke. The incidence of major bleeding was not greater in the dabigatran group than in the aspirin group, but there were more clinically relevant nonmajor bleeding events in the dabigatran group. (Funded by Boehringer Ingelheim; RE-SPECT ESUS ClinicalTrials.gov number, NCT02239120.).

Comparative effectiveness and safety of low-strength and high-strength direct oral anticoagulants compared with warfarin: a sequential cohort study

OBJECTIVES

The aim of this study was to compare effectiveness and safety of low-strength and high-strength direct oral anticoagulants (DOACs) with warfarin in the Australian Veteran population.

DESIGN

Sequential cohort study using inverse probability of treatment weighting (IPTW) and propensity score matching. Initiators of high-strength (apixaban 5 mg, dabigatran 150 mg, rivaroxaban 20 mg) and low-strength DOACS (apixaban 2.5 mg, dabigatran 110 mg, rivaroxaban 15 mg) were compared with warfarin initiators.

SETTING

Australian Government Department of Veterans' Affairs claims database.

PARTICIPANTS

4836 patients who initiated oral anticoagulants (45.8%, 26.0% and 28.2% on low-strength, high-strength DOACs and warfarin, respectively) between August 2013 and March 2015. Mean age was 85, 75 and 83 years for low-strength, high-strength DOACs and warfarin initiators, respectively.

MAIN OUTCOME MEASURES

One-year risk of hospitalisation for ischaemic stroke, any bleeding event or haemorrhagic stroke. Secondary outcomes were 1-year risk of hospitalisation for myocardial infarction and death.

RESULTS

Using the IPTW method, no difference in risk of ischaemic stroke or bleeding was found with low-strength DOACs compared with warfarin. As a class, no increased risk of myocardial infarction was found for low-strength DOACs, however, risk was elevated for apixaban (HR 2.25, 95% CI 1.23 to 4.13). For high-strength DOACs, no difference was found for ischaemic stroke compared with warfarin, however, there was a significant reduction in risk of bleeding events (HR 0.63, 95% CI 0.44 to 0.89) and death (HR 0.40, 95% CI 0.28 to 0.58). Propensity score matching showed no difference in risk of ischaemic stroke or bleeding.

CONCLUSION

We found that in the practice setting both DOAC formulations were similar to warfarin with regard to effectiveness and had no increased risk of bleeding.

Secondary Bleeding During Acute Experimental Intracerebral Hemorrhage

Background and Purpose- Mechanisms contributing to acute hematoma growth in intracerebral hemorrhage are not well understood. Neuropathological studies suggest that the initial hematoma may create mass effect that can tear vessels in the vicinity by shearing, causing further bleeding and hematoma growth. Methods- To test this in mice, we simulated initial intracerebral hemorrhage by intrastriatal injection of a liquid polymer that coagulates upon contact with tissue and measured the presence and volume of bleeding secondary to the mass effect using Hemoglobin ELISA 15 minutes after injection. Results- Secondary hemorrhage occurred in a volume-dependent (4, 7.5, or 15 μL of polymer) and rate-dependent (0.05, 0.5, or 5 μL/s) manner. Anticoagulation (warfarin or dabigatran) exacerbated the secondary hemorrhage volume. In a second model of hematoma expansion, we confirmed that intrastriatal whole blood injection (15 μL, 0.5 μL/s) also caused secondary bleeding, using acute Evans blue extravasation as a surrogate. Anticoagulation once again exacerbated secondary hemorrhage after intrastriatal whole blood injection. Secondary hemorrhage directly and significantly correlated with arterial blood pressures in both nonanticoagulated and anticoagulated mice, when modulated by phenylephrine or labetalol. Conclusions- Our study provides the first proof of concept for secondary vessel rupture and bleeding as a potential mechanism for intracerebral hematoma growth.

The acceptability of a direct oral anticoagulant monitoring regimen among patients with atrial fibrillation: a pilot study

Background The direct oral anticoagulants (DOACs) offer several advantages over warfarin in the management atrial fibrillation, including the provision of fixed dosing without a requirement for regular monitoring. Recently however the subject of DOAC monitoring has been probed after several post-hoc analyses demonstrated an association between plasma levels and efficacy and safety events. Objective The aim of this pilot study was to explore the acceptability of DOAC plasma monitoring amongst patients with atrial fibrillation and the factors that may influence these attitudes. Method A simple DOAC monitoring schedule based on the dabigatran pharmacokinetic profile was developed. A cross-sectional survey was distributed to patients with atrial fibrillation asking them to indicate their likelihood of taking a particular DOAC subjected to plasma monitoring. Results Thirty patients participated in the study. Most patients (63.3%) favoured taking a DOAC subjected to monitoring under the proposed schedule, citing increased efficacy and reduced toxicity as the reasons for their response. Conclusion There is some suggestion that atrial fibrillation patients may in fact favour taking a DOAC subjected to infrequent monitoring if this enhanced safety and efficacy.

Effectiveness and safety of oral anticoagulants in older adults with non-valvular atrial fibrillation and heart failure

Direct oral anticoagulants (DOACs) are at least as efficacious and safe as warfarin among non-valvular atrial fibrillation (NVAF) patients; limited evidence is available regarding NVAF patients with heart failure (HF). US Medicare enrollees with NVAF and HF initiating DOACs (apixaban, rivaroxaban, dabigatran) or warfarin were selected. Propensity score matching and Cox models were used to estimate the risk of stroke/systemic embolism (SE), major bleeding (MB), and major adverse cardiac events (MACE) comparing DOACs versus warfarin and DOACs versus DOACs. We identified 10,570 apixaban-warfarin, 4,297 dabigatran-warfarin, 15,712 rivaroxaban-warfarin, 4,263 apixaban-dabigatran, 10,477 apixaban-rivaroxaban, and 4,297 dabigatran-rivaroxaban matched pairs. Compared to warfarin, apixaban had lower rates of stroke/SE (hazard ratio = 0.64, 95% confidence interval = 0.48-0.85), MB (hazard ratio = 0.66, 0.58-0.76), and MACE (hazard ratio = 0.73,0.67-0.79); dabigatran and rivaroxaban had lower rates of MACE (hazard ratio = 0.87,0.77-0.99; hazard ratio = 0.84, 0.79-0.89, respectively). Rivaroxaban had a lower stroke/SE rate (hazard ratio = 0.65, 0.52-0.81) and higher MB rate (hazard ratio = 1.18, 1.08-1.30) versus warfarin. Compared to dabigatran and rivaroxaban, apixaban had lower MB (hazard ratio = 0.71, 0.57-0.89; hazard ratio = 0.55, 0.49-0.63) and MACE rates (hazard ratio = 0.80, 0.69-0.93; hazard ratio = 0.86, 0.79-0.94), respectively. All DOACs had lower MACE rates versus warfarin; differences were observed in stroke/SE and MB. Our findings provide insights about OAC therapy among NVAF patients with HF.

New versus Old Oral Anticoagulants: How Can We Set the Scale Needle? Considerations on a Case Report

Ischemic stroke is a complex multifactorial disorder. Anticoagulation is a growing research area, with the main goal of preventing systemic embolization and stroke. We report the case of a 41-year-old woman with antiphospholipid syndrome who was unsuccessfully treated with Dabigatran, a new oral anticoagulant, as she developed a major stroke involving the right carotid artery, due to deep venous thrombosis with pulmonary embolism. We therefore suggest a closer monitoring of the safety and efficacy of dabigatran. Moreover, in the presence of multifactorial causes of pro-coagulation, we believe that warfarin should remain the mainstay of oral anticoagulation.

Vascular protease-activated receptor 4 upregulation, increased platelet aggregation, and coronary lipid deposits induced by long-term dabigatran administration - results from a diabetes animal model

Essentials The impact of long-term thrombin inhibition outside the coagulation cascade is far from clear. We aimed to assess the impact of dabigatran etexilate (DE) in diabetic and control rats. In diabetic rats, DE increased platelet aggregation and lead to coronary lipid deposits. Long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk. SUMMARY: Background Besides its role in the coagulation cascade, thrombin contributes to platelet aggregation and to a plethora of non-hemostatic functions. Objectives To assess the impact of long-term thrombin inhibition with dabigatran etexilate (DE) on platelet aggregation and on extrahemostatic thrombin-related functions in diabetic and control rats. Methods Markers of inflammation, endothelial dysfunction, oxidative stress, angiogenesis and cell adhesion molecules were quantified in control rats (Control; n = 6), DE-treated control rats (Control-Dabi; n = 8), diabetic rats (Diabetes; n = 5), and DE-treated diabetic rats (Diabetes-Dabi; n = 8). Agonist-induced platelet aggregation, aortic and coronary lipid deposits and aortic protease-activated receptor 4 (PAR4) expression were also assessed. Results Control-Dabi rats showed significantly higher high-sensitivity C-reactive protein, von Willebrand factor (VWF), vascular endothelial growth factor (VEGF) and fibronectin levels, and significantly lower PAR4 agonist-induced aggregation, than Control rats. Control-Dabi rats also showed mild aortic lipid deposits, whereas no such changes were observed in Control rats. Diabetes-Dabi rats showed significantly higher VWF, VEGF and fibronectin levels than Diabetes rats, and similar PAR4 agonist-induced aggregation as Diabetes rats, and significantly higher ADP-induced aggregation than Diabetes rats. Coronary lipid deposits were observed in 75% of Diabetes-Dabi rats and in none of the Diabetes rats. PAR4 expression was 20.4% higher in Control-Dabi rats and 27.4% higher in Diabetes-Dabi rats than in their non-treated peers. Conclusions This study indicates that long-term thrombin inhibition increases vascular PAR4 expression, promotes atherosclerosis-related mechanisms, and, in diabetic rats, increases platelet aggregation and favors the occurrence of coronary lipid deposits. These experimental data suggest that long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk, particularly in the presence of diabetes.