Dabigatran Treatment Research Articles

L-shaped association between gamma-glutamyl transferase-to-albumin ratio and dabigatran-related bleeding in non-valvular atrial fibrillation patients: a multicenter cohort study.

The correlation between the gamma-glutamyl transferase-to-albumin ratio (GAR) and the risk of bleeding in patients with non-valvular atrial fibrillation (NVAF) undergoing treatment with the dabigatran anticoagulant is poorly understood. This study aims to explore whether GAR is associated with bleeding events among patients with NVAF receiving dabigatran anticoagulant therapy. We conducted a multicenter, observational cohort study in 12 Chinese hospitals from six provinces, including Beijing, Shanghai and Guangzhou, to evaluate the effectiveness and safety of dabigatran (110 mg) treatment in NVAF patients who were consecutively enrolled during February 2015 and December 2017. All patients had completed a 3-month follow-up period. The baseline variable of interest was the GAR, and the outcome variable was the occurrence of bleeding events. Both univariate and multivariate Cox proportional hazard models were used to evaluate the relationship between GAR and bleeding outcome. This prospective cohort study included a total of 834 patients (mean age 65.6±11.1 years; 56.8% male). Overall, 82 subjects experienced bleeding. The patients were categorized based on the tertiles of the GAR. Participants in tertile 2 (0.59-1.03) [hazard ratio (HR): 0.28; 95% confidence interval (CI): 0.14-0.55; P<0.001] and tertile 3 (≥1.04) (HR: 0.47; 95% CI: 0.25-0.89; P=0.02) exhibited a lower rate of bleeding compared to the reference group (T1: ≤0.58). Multivariable models with restricted cubic splines demonstrated a nonlinear relationship between GAR and bleeding outcome, with a GAR inflection point of 0.68. The HR (95% CI) was 0.05 (0.01-0.31) (P=0.002) for GAR values <0.68 and 0.96 (0.70-1.31) (P=0.78) for GAR values ≥0.68. Moreover, the correlation between decreased GAR and an increase in bleeding events remained consistent across various subgroups. GAR is a prevalent, independent predictor of dabigatran-related bleeding in NVAF patients. Moreover, a significant L-shaped association between GAR and bleeding events has been observed.

Effects of dabigatran, rivaroxaban, and apixaban on fibrin network permeability, thrombin generation, and fibrinolysis

Introduction There are important pharmacological differences between direct oral anticoagulants (DOAC) and a deeper knowledge of how they influence different aspects of hemostasis in patients on treatment is desirable. Materials and methods Blood samples from patients on dabigatran (n = 23), rivaroxaban (n = 26), or apixaban (n = 20) were analyzed with a fibrin network permeability assay, a turbidimetric clotting and lysis assay, the calibrated automated thrombogram (CAT), plasma levels of thrombin-antithrombin complex (TAT) and D-dimer, as well as DOAC concentrations, PT-INR and aPTT. As a comparison, we also analyzed samples from 27 patients on treatment with warfarin. Results Patients on dabigatran had a more permeable fibrin network, longer lag time (CAT and turbidimetric assay), and lower levels of D-dimer in plasma, compared with patients on rivaroxaban- and apixaban treatment, and a more permeable fibrin network than patients on warfarin. Clot lysis time was slightly longer in patients on dabigatran than in patients on rivaroxaban. Warfarin patients formed a more permeable fibrin network than patients on apixaban, had longer lag time than patients on rivaroxaban (CAT assay), and lower peak thrombin and ETP compared to patients on treatment with both FXa-inhibitors. Conclusions Results from this study indicate dabigatran treatment is a more potent anticoagulant than apixaban and rivaroxaban. However, as these results are not supported by clinical data, they are probably more related to the assays used and highlight the difficulty of measuring and comparing the effect of anticoagulants.

Perioperative Treatment with Rivaroxaban and Dabigatran on Changes of Coagulation and Platelet Activation Biomarkers following Left Atrial Appendage Closure.

Insufficient data exist regarding the investigation of the impact of novel oral anticoagulants (NOACs) on coagulation activation biomarkers in the context of left atrial appendage closure (LAAC) and device-related thrombosis (DRT). The study was designed to investigate the changes and presence of coagulation activation biomarkers between different antithrombotic strategies following LAAC. A total of 120 nonvalvular atrial fibrillation patients intolerant of long-term anticoagulants, who underwent successful WATCHMAN closure implantation, were enrolled (rivaroxaban, n = 82; dabigatran, n = 38). Blood samples were obtained from left atrium (LA) and left atrial appendage (LAA) during the operation and fasting blood samples on the same day of LAAC and 45 days after discharge. The biochemical indicators, thrombin-antithrombin complex (TAT), soluble P-selectin (sP-selectin), von Willebrand factor (vWF), and CD40 ligand (CD40L), were measured by enzyme-linked immunosorbent assay. The primary endpoints of this study were the efficacy and safety characteristics of different antithrombotic strategies, including DRT incidence, stroke or transient ischemic attack, systemic embolism, and clinical major and nonmajor bleeding complications during the follow-up of 180 days. The results revealed that TAT, vWF, sP-selectin, and CD40L levels in vein were significantly reduced by 2.4% (p = 0.043), 5.0% (p < 0.001), 8.7% (p < 0.001), and 2.5% (p = 0.043) from their baseline levels after rivaroxaban treatment. Conversely, no significant changes were detected in the dabigatran group. Furthermore, the plasma levels of platelet activation biomarkers (CD40L and sP-selectin) in both LA and LAA groups were significantly lower after anticoagulation with rivaroxaban, as compared to dabigatran treatment (CD40L: 554.62 ± 155.54 vs. 445.02 ± 130.04 for LA p = 0.0013, 578.51 ± 156.28 vs. 480.13 ± 164.37 for LAA p = 0.0052; sP-selectin: 2849.07 ± 846.69 vs. 2225.54 ± 799.96 for LA p = 0.0105, 2915.52 ± 1402.40 vs. 2203.41 ± 1061.67 for LAA p = 0.0022). Notably, the present study suggests that rivaroxaban may be more effective in the prevention of DRT for patients undergoing LAAC.

Dabigatran for Treatment and Secondary Prevention of Venous Thromboembolism in Pediatric Congenital Heart Disease.

Congenital heart disease (CHD) is common in children and associated with greater risk of thrombotic complications. Management of these complications with standard-of-care treatment is suboptimal for these children. The effectiveness and safety of dabigatran were demonstrated in pivotal pediatric studies for the treatment of acute venous thromboembolism (VTE; NCT01895777) and secondary VTE prevention (NCT02197416). We report safety and efficacy outcomes from subgroup analyses of these studies for children with CHD (diagnosed according to local practice) and those without. In NCT01895777, 17/21 (81.0%) and 16/27 (59.3%) patients with CHD (including cyanotic) treated with dabigatran and standard of care, respectively, met the primary end point (complete thrombus resolution, freedom from recurrent VTE, and freedom from VTE-related death; odds ratio [OR], 0.34 [95% CI, 0.08-1.23]). In patients without CHD, 41.0% (n=64) versus 34.9% (n=22) achieved this end point with the respective treatments (OR, 0.77 [95% CI, 0.42-1.41]). Although numerical differences were observed, no heterogeneity in treatment effect of dabigatran on the composite primary end point was detected in patients with and without CHD (interaction P =0.2674). In NCT02197416, recurrent VTE at 12 months occurred in 0/17 patients with CHD versus 3/194 (1.5%) without. No patient with CHD experienced major or clinically relevant nonmajor bleeding events. Data on favorable anticoagulant alternatives for the unmet needs of children with CHD are emerging, and our exploratory results suggest that dabigatran could be an appropriate treatment choice, although challenging sample size limitations in pediatric studies require cautious interpretation of findings. URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01895777, NCT02197416.

Abstract TP240: Safety of Dabigatran in Patients With Acute Minor Non-Cardioembolic Ischemic Stroke or Transient Ischemic Attack and Cerebral Microbleeds: A Post Hoc Analysis of the DATAS-II Randomized Trial

Introduction: Cerebral microbleeds are reported to predict risk of hemorrhagic transformation (HT) in patients with acute ischemic stroke. We aimed to investigate whether the effect of dabigatran (vs. aspirin) in patients with acute minor non-cardioembolic ischemic stroke/TIA is modified by baseline microbleeds on MRI. Methods: This is a post hoc analysis of the DATAS-II trial that randomized 305 patients with acute minor non-cardioembolic ischemic stroke/TIA to dabigatran (150/110 mg twice daily) or aspirin (81 mg daily) for 30 days. MRIs of patients with T2*-weighted sequences on their baseline scans underwent blinded central adjudication for microbleeds. Results: A total of 251 participants (mean age=66±13 years, 36% women, median [IQR] time from symptom onset to randomization 40 [27-55] hours; mean NIHSS=1.5±1.9) were included in these analyses, of whom 82 (33%) had baseline microbleeds. On 30-day MRI, 6% (n=14) developed HT, and 80% (n=191) achieved mRS 0-1 at 90 days. In multivariable logistic regression analyses, we found no association between microbleeds and HT (adjusted odds ratio [aOR], 0.76; 95% CI, 0.18-3.23) on 30-day MRI or mRS 0-1 at 90 days (aOR, 1.54; 95% CI, 0.70-3.41). The rates of HT and mRS 0-1 in patients with microbleeds were 3% on dabigatran and 4% on aspirin (OR, 0.71; 95% CI, 0.06-8.17), and 74% on dabigatran and 84% on aspirin (OR, 0.54; 95% CI, 0.18-1.64), respectively. The presence, severity, or location of microbleeds did not modify the effect of dabigatran on these outcomes (p-interaction&gt;0.05). Conclusions: Early dabigatran treatment appears safe in patients with acute minor non-cardioembolic ischemic stroke/TIA and hemorrhage-prone cerebral small vessel disease marked by microbleeds on MRI.

Mechanical prosthetic mitral valve thrombosis during dabigatran treatment

Dabigatran has been approved for prevention of thromboembolic complications in non-valvular atrial fibrillation. We present a case of a mechanical prosthetic mitral valve thrombosis during anticoagulation with dabigatran, switched in the last three months after 10 years treatment with warfarin. The patient presented with acute respiratory failure and decompensated heart failure. She was initially treated with unfractioned heparin and then was sent for emergency surgery for cardiogenic shock. As emerging from contemporary evidence and as recommended by guidelines, dabigatran, as well as the other direct oral anticoagulants, should be avoided in patients with mechanical valve prosthesis. Echocardiography is indicated if dyspnoea develops in such patients.

Use of Direct Acting Oral Anticoagulants in Elderly Patients with Atrial Fibrillation: A Multicenter, Cross-Sectional Study in Spain.

Non-vitamin K antagonist oral anticoagulants (NOACs) have substantially improved anticoagulation. However, data on NOAC use among elderly patients are scarce. We sought to describe NOAC use among elderly AF patients in Spain. We performed a non-interventional, multicenter, multispecialty, cross-sectional study in elderly (≥75 years) AF patients treated with NOACs for stroke prevention. Patients' characteristics by NOAC treatment were compared using standardized differences (SDD). NOAC dosing was classified according to the Spanish summary of products characteristics (SmPC) into appropriate (recommended dose) and inappropriate (under and overdosed). Multivariate logistic regression analyses were used to explore factors associated with inappropriate dosing. 500 patients were included. Mean (SD) age was 81.5 (4.7) years, and 50% were women. Mean (SD) creatinine clearance was 57.4 mL/min (18.8), and 23.6% were frail. Dabigatran treatment totaled 38.4%, rivaroxaban 15.2%, apixaban 33.2%, and edoxaban 13.2%. Almost one-fourth of elderly patients treated with NOACs in Spain were inappropriately dosed (underdosing 14.4% and overdosing 9.6%). Underdosing was significantly associated with weight (OR = 1.03, 95%CI = 1.0-1.1), while higher a EHRA score decreased the risk of underdosing (OR = 0.47, 95%CI = 0.2-1.0). Overdosing was significantly associated with a history of ischemic stroke (OR = 2.95, 95%CI = 1.1-7.7). Addressing incorrect dosing among elderly AF patients is relevant to improve patient outcomes.

Favourable outcome of multisystem venous thrombosis associated with novel SERPINC1 mutation after treated with dabigatran: a case report with 7-year follow-up

BackgroundMutations in SERPINC1lead to deficiency in antithrombin (AT) which is an endogenous anticoagulant ofnormal hemostasis and could result in venousthromboembolism (VTE). Case presentationA 61-year-old male patientwith recurrent thrombosis returned to the hospital with multiple cerebralthrombosis after voluntary cessationof dabigatran therapy. Laboratory tests revealed a type I AT deficiency in thispatient and further whole exome sequencing (WES) identified a novelheterozygous frameshift duplication (c.233_236dup, p.Val80Alafs*26) in SERPINC1gene. Long-term dabigatran treatment was given and no recurrence or sideeffects were found within the followed 5 years.ConclusionA multisystem VTE patient witha novel SERPINC1 mutation (c.233_236dup, p.Val80Alafs*26) reached a favourableoutcome after dabigatran treatment.

Effects of dabigatran versus warfarin on 2-year cognitive outcomes in old patients with atrial fibrillation: results from the GIRAF randomized clinical trial

BackgroundObservational studies support a role for oral anticoagulation to reduce the risk of dementia in atrial fibrillation patients, but conclusive data are lacking. Since dabigatran offers a more stable anticoagulation, we hypothesized it would reduce cognitive decline when compared to warfarin in old patients with atrial fibrillation.MethodsThe GIRAF trial was a 24-month, randomized, parallel-group, controlled, open-label, hypothesis generating trial. The trial was done in six centers including a geriatric care unit, secondary and tertiary care cardiology hospitals in São Paulo, Brazil. We included patients aged ≥ 70 years and CHA2DS2-VASc score > 1. The primary endpoint was the absolute difference in cognitive performance at 2 years. Patients were assigned 1:1 to take dabigatran (110 or 150 mg twice daily) or warfarin, controlled by INR and followed for 24 months. Patients were evaluated at baseline and at 2 years with a comprehensive and thorough cognitive evaluation protocol of tests for different cognitive domains including the Montreal Cognitive Assessment (MoCA), Mini-Mental State Exam (MMSE), a composite neuropsychological test battery (NTB), and computer-generated tests (CGNT).ResultsBetween 2014 and 2019, 5523 participants were screened and 200 were assigned to dabigatran (N = 99) or warfarin (N = 101) treatment. After adjustment for age, log of years of education, and raw baseline score, the difference between the mean change from baseline in the dabigatran group minus warfarin group was − 0.12 for MMSE (95% confidence interval [CI] − 0.88 to 0.63; P = 0.75), 0.05 (95% CI − 0.07 to 0.18; P = 0.40) for NTB, − 0.15 (95% CI − 0.30 to 0.01; P = 0.06) for CGNT, and − 0.96 (95% CI − 1.80 to 0.13; P = 0.02) for MoCA, with higher values suggesting less cognitive decline in the warfarin group.ConclusionsFor elderly patients with atrial fibrillation, and without cognitive compromise at baseline that did not have stroke and were adequately treated with warfarin (TTR of 70%) or dabigatran for 2 years, there was no statistical difference at 5% significance level in any of the cognitive outcomes after adjusting for multiple comparisons.Trial registrationCognitive Impairment Related to Atrial Fibrillation Prevention Trial (GIRAF), NCT01994265.

Dabigatran in the treatment and secondary prophylaxis of venous thromboembolism in children with thrombophilia

AbstractIn the phase 2b/3 DIVERSITY trial, 3 months treatment with dabigatran was noninferior to standard of care (SOC) for acute venous thromboembolism (VTE) in children. In a single-arm, phase 3, secondary VTE prevention study, up to 12 months dabigatran use was associated with favorable safety. Dabigatran is approved by the European Medicines Agency and US Food and Drug Administration for pediatric indications. We assessed primary composite efficacy (complete thrombus resolution and freedom from VTE recurrence/VTE-related death) in subgroups with thrombophilia vs those with negative/unknown thrombophilia status in the DIVERSITY trial and safety in both studies. Thrombophilia types were similar between the DIVERSITY trial (total population) and secondary prevention studies: factor V Leiden, 42% vs 33%; prothrombin mutation (G20210A), 19% vs 17%; antithrombin deficiency, 15% vs 20%; protein C/S deficiency, 23% vs 25%; and antiphospholipid antibodies, 18% vs 20% of patients, respectively. In DIVERSITY, 36% and 22% of thrombophilia subgroup patients treated with dabigatran and SOC, respectively, met the primary end point (Mantel-Haenszel–weighted rate difference, −0.135; 95% confidence interval, −0.36 to 0.08; noninferiority P = .0014); comparable to the total DIVERSITY trial population (46% vs 42%) showing dabigatran noninferiority to SOC. Within this subgroup, numerically fewer patients experienced VTE recurrence or progression of index thrombus in the dabigatran treatment group vs SOC. In the secondary prevention study, VTE recurrence at 12 months occurred in 2.8% of patients with thrombophilia vs 0% with negative/unknown thrombophilia. Safety profiles were consistent with those reported previously. Although they should be interpreted with caution, these exploratory findings suggest dabigatran could be an appropriate long-term anticoagulant for children with thrombophilia. These trials were registered at www.clinicaltrials.gov as #NCT01895777 and #NCT02197416.

Evaluation of a pharmacist-led intervention to improve medication adherence in patients initiating dabigatran treatment: a comparison with standard pharmacy practice in Poland

BackroundDabigatran is a direct thrombin inhibitor used to treat cardiac arrhythmias, and rates of non-adherence to dabigatran in Polish populations are high. The current study examined how a pharmacist-led intervention of counselling with pictogram-enhanced medication instructions, and smartphone medication reminders, can improve adherence to dabigatran.MethodsA 3-month pharmacist-led intervention was conducted in community pharmacies in Poland on 325 men and women filling a dabigatran prescription for the first time. Participating pharmacies were assigned into the Control Group (n = 172 patients) or the Intervention Group (n = 153 patients). The primary outcome of this prospective study was self-reported medication adherence assessed at 3 time points (day 7, day 21, and day 90) after initiation of dabigatran.ResultsPatients in the Intervention Group were significantly more adherent (mean days on Dabigatan/week) than the Control Group at 7 days (6.0 ± 0.9 vs 5.4 ± 1.1, p < 0.0001), 21 days (5.6 ± 1.0 vs 4.9 ± 1.3, p < 0.0001), and 90 days (5.5 ± 1.3 vs 4.4 ± 2.0, p < 0.0001), respectively. The percentage of patients in the Intervention Group who reported taking dabigatran twice/day as prescribed was significantly higher than the Control Group at 7 days (82.7% vs 71.4%, p = 0.0311), at 21 days (84.4% vs 58%, p < 0.0001), and at 90 days (78.4% vs 39.7%, p < 0.0001), respectively. The proportion of patients fully adherent (every day, twice/day) at 90 days was significantly higher in the Intervention Group than in the Control Group (26.1% vs 13.2%, p = 0.0145).ConclusionsOur findings support the role for interventions in community pharmacies in Poland to improve medication adherence, thus providing evidence for the efficacy of a pharmacist-led pictogram and smartphone-based program to support optimal dabigatran treatment.

Fibrin(ogen) Is Constitutively Expressed by Differentiated Intestinal Epithelial Cells and Mediates Wound Healing.

Fibrinogen is a large molecule synthesized in the liver and released in the blood. Circulating levels of fibrinogen are upregulated after bleeding or clotting events and support wound healing. In the context of an injury, thrombin activation drives conversion of fibrinogen to fibrin. Fibrin deposition contains tissue damage, stops blood loss, and prevents microbial infection. In most circumstances, fibrin needs to be removed to allow the resolution of inflammation and tissue repair, whereas failure of this may lead to the development of various disorders. However, the contribution of fibrinogen to tissue inflammation and repair is likely to be context-dependent. In this study, the concept that fibrin needs to be removed to allow tissue repair and to reduce inflammation is challenged by our observations that, in the intestine, fibrinogen is constitutively produced by a subset of intestinal epithelial cells and deposited at the basement membrane as fibrin where it serves as a substrate for wound healing under physiological conditions such as epithelial shedding at the tip of the small intestinal villus and surface epithelium of the colon as well as under pathological conditions that require rapid epithelial repair. The functional integrity of the intestine is ensured by the constant renewal of its simple epithelium. Superficial denuding of the epithelial cell layer occurs regularly and is rapidly corrected by a process called restitution that can be influenced by various soluble and insoluble factors. Epithelial cell interaction with the extracellular matrix greatly influences the healing process by acting on cell morphology, adhesion, and migration. The functional contribution of a fibrin(ogen) matrix in the intestine was studied under physiological and pathological contexts. Our results (immunofluorescence, immunoelectron microscopy, and quantitative PCR) show that fibrin(ogen) is a novel component of the basement membrane associated with the differentiated epithelial cell population in both the small intestine and colon. Fibrin(ogen) alone is a weak ligand for epithelial cells and behaves as an anti-adhesive molecule in the presence of type I collagen. Furthermore, the presence of fibrin(ogen) significantly shortens the time required to achieve closure of wounded epithelial cell monolayers and co-cultures in a PI3K-dependent manner. In human specimens with Crohn’s disease, we observed a major accumulation of fibrin(ogen) throughout the tissue and at denuded sites. In mice in which fibrin formation was inhibited with dabigatran treatment, dextran sulfate sodium administration provoked a significant increase in the disease activity index and pathological features such as mucosal ulceration and crypt abscess formation. Taken together, these results suggest that fibrin(ogen) contributes to epithelial healing under both normal and pathological conditions.

Comparison of Dabigatran Versus Warfarin Treatment for Prevention of New Cerebral Lesions in Valvular Atrial Fibrillation

Warfarin is the standard anticoagulation therapy for valvular atrial fibrillation (AF); however, new oral anticoagulants have emerged as an alternative. We compared the efficacy and safety of dabigatran with conventional treatment in AF associated with left-sided valvular heart disease (VHD), including mitral stenosis (MS). Patients with AF and left-sided VHD were randomly assigned to receive dabigatran or conventional treatment. The primary end point was the occurrence of clinical stroke or a new brain lesion (silent brain infarct and microbleed) on 1-year follow-up brain magnetic resonance imaging. Patients in the dabigatran group were switched from warfarin (n=52), antiplatelets alone (n=5), or no therapy (n=2) to dabigatran. In the conventional group, 53 used warfarin (including 42 MS patients), and 7 used antiplatelets. No death or clinical stroke event occurred in either group during follow-up. Silent brain infarct and microbleed occurred in 20 and 2 patients in the dabigatran group and 20 and 4 patients in the conventional treatment group. The incidence rate of the primary end point did not significantly differ between groups (34% vs 40%, relative risk 0.87, 95% confidence interval 0.59 to 1.29, p=0.491). The primary end point rate was similar between groups in 82 patients (40 in the dabigatran group and 42 in the conventional group) with MS (32% vs 34%, relative risk 0.93, 95% confidence interval: 0.57 to 1.50, p=0.759). In conclusion, primary end point rates after treatment with dabigatran were similar to conventional treatment in patients with significant VHD and AF. New oral anticoagulants could be a reasonable alternative to warfarin in patients with AF and VHD, which should be confirmed in future large-scale studies.

Direct Thrombin Inhibitor Dabigatran Compromises Pulmonary Endothelial Integrity in a Murine Model of Breast Cancer Metastasis to the Lungs; the Role of Platelets and Inflammation-Associated Haemostasis.

Activation of the coagulation cascade favours metastatic spread, but antithrombotic therapy might also have detrimental effects on cancer progression. In this study, we characterized the effects of dabigatran, a direct reversible thrombin inhibitor, on the pulmonary endothelial barrier and metastatic spread in a murine model of breast cancer metastasis. Dabigatran etexilate (100 mg kg−1) was administered to mice twice daily by oral gavage. Pulmonary metastasis, pulmonary endothelium permeability in vivo, and platelet reactivity were evaluated after intravenous injection of 4T1 breast cancer cells into BALB/c mice. The effect of dabigatran on platelet-dependent protection of pulmonary endothelial barrier in the presence of an inflammatory stimulus was also verified in vitro using human lung microvascular endothelial cell (HLMVEC) cultures. Dabigatran-treated mice harbored more metastases in their lungs and displayed increased pulmonary endothelium permeability after cancer cell injection. It was not associated with altered lung fibrin deposition, changes in INFγ, or complement activation. In the in vitro model of the pulmonary endothelial barrier, dabigatran inhibited platelet-mediated protection of pulmonary endothelium. In a murine model of breast cancer metastasis, dabigatran treatment promoted pulmonary metastasis by the inhibition of platelet-dependent protection of pulmonary endothelial barrier integrity.

Do non-vitamin K antagonist oral anticoagulants increase the risk of myocardial infarction?

Non-vitamin K antagonist oral anticoagulants (NOACs), compared with warfarin, have a favorable risk-benefit profile. However, in the RE-LY study in patients with atrial fibrillation (AF), the number of patients with MI was higher in the dabigatran group as compared to the warfarin group. Many meta-analyses showed that dabigatran treatment led to an increased risk of myocardial infarction (MI). Large real-world data (RWD) did not confirm an increase in the risk of MI during dabigatran treatment. In our meta-analysis we excluded RWD, and each of the four drugs was evaluated in two key-phase III randomized controlled trials: in patients with AF and patients with AF and chronic coronary syndrome or acute coronary syndrome treated with percutaneous coronary interventions. In each study, warfarin was the comparator for NOACs. In this homogeneous group of patients, dabigatran, in direct comparison with warfarin, significantly increased the risk of MI by about 30%. Moreover, the risk of MI was also significantly higher than the opposite effect of activated factor (F) X inhibitors (FXa inhibitors) vs. warfarin. In our network meta-analysis, considering individual NOACs in recommended doses, we found an increased risk of MI compared to warfarin only in patients treated with dabigatran 150 mg twice a day and, in particular, 110 mg twice a day. In this review we present evidence supporting our opinion that in patients with AF and coronary stenting, the choice of NOACs (direct FXa vs. thrombin inhibitors) is equally as important as choosing the optimal antiplatelet therapy (single or dual antiplatelet therapy).

Cost-effectiveness of anticoagulants for preventing stroke in patients with non-valvular atrial fibrillation in mainland China.

With the high cost, the long-term persistence of new oral anticoagulants (NOACs) was lower than that of warfarin in Chinese patients with non-valvular atrial fibrillation (NVAF) for a long time. The prices of NOACs (apixaban, rivaroxaban and dabigatran) decreased significantly over the past year in mainland China. The objective of this study was to evaluate the cost-effectiveness of NOACs versus warfarin for preventing stroke in patients with NVAF from a Chinese healthcare system perspective. A decision tree and Markov model were used to assess the treatment strategies of four NOACs versus warfarin over a lifetime horizon. For each treatment strategy, the total lifetime cost, quality-adjusted life-years (QALY) and incremental cost-effectiveness ratio (ICER) were calculated. The impact of parameter uncertainties on base-case analysis results was evaluated using sensitivity analyses. In the base-case analysis, compared with warfarin, apixaban had a decreased total lifetime cost of USD 389 and rivaroxaban of USD 1482, while low-dose dabigatran had an increased total lifetime cost of USD 925 and high-dose dabigatran of USD 6641, with QALY increasing by 0.53, 1.32, 0.92 and 1.83, respectively. The ICER of low-dose dabigatran versus warfarin was USD 1005 per QALY gain, while those of apixaban (-USD 734 per QALY gain) and rivaroxaban (-USD 1123 per QALY gain) were negative. One-way and probabilistic sensitivity analyses indicated that the base-case results were robust by applying certain varying parameters to the model. These four NOAC (apixaban, rivaroxaban, low-dose dabigatran and high-dose dabigatran) treatment strategies were cost-effective compared with warfarin and recommended as substitutes for warfarin treatment for preventing stroke in patients with NVAF in the healthcare system of China, which might be driven by large drug price reductions in the past year.

Dabigatran as first-line treatment for heparin-induced thrombocytopenia in the intensive cardiac care setting

Abstract Introduction Heparin-induced thrombocytopenia (HIT) is a rare immune-mediated disorder related to the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) which is associated with increased risk of vascular thrombosis. HIT constitute a relevant and not so uncommon clinical issue in the intensive cardiac care unit setting. Parenteral non-heparin anticoagulants are recommended for the treatment of HIT. The efficacy of dabigatran, direct oral anticoagulant, is poorly documented in this indication. In laboratory-confirmed HIT only few cases with short-term use and early conversion to and from another anticoagulant were reported. Purpose The purpose of our study was to evaluate the efficacy and safety of dabigatran as a first-line and the only one anticoagulant used in the treatment of HIT. Methods We prospectively enrolled 5 patients with the diagnosis of HIT who were hospitalized in our intensive cardiac care unit in 2017–2021. Heparin was stopped immediately on the suspicion of HIT and off-label dabigatran therapy was initiated the same day. There were no conversion to another non-heparin anticoagulant – dabigatran was used continuously from suspicion of HIT for at least 3 months. In all patients we used latex immunoassay to confirm the diagnosis of HIT. Lower-extremity compression ultrasonography was performed to exclude thrombosis. We distinguished HIT with thrombosis (HITT) and isolated HIT (HIT without thrombosis). The minimal follow-up period on dabigatran treatment was 3 months and the maximal 4 years. Results All the patients were male with the median age of 73 years (interquartile range, 52–78 years) and all were exposed to both, UFH and LMWH. The median platelet (PLT) count before exposition to heparin was 182000/μl (interquartile range, 171000/μl–321000/μl). Platelet count fall &amp;gt;50% was observed after a median time of 9 days (interquartile range, 7–11 days) after exposition to heparin and a median PLT count nadir was 87000 μl/l (interquartile range, 25000/μl–103000/μl). Two patients had intermediate and three high probability of HIT. HITT was diagnosed in one patient. The manifestation of HITT was upper-extremity arterial thrombosis and pulmonary embolism. Four patients were diagnosed with isolated HIT. PLT count recovery &amp;gt;15ehab724.2982/μl was observed after a median time of 3 days on dabigatran treatment (interquartile range, 2–7 days). In the patient with HITT, a complete resolution of upper-limb arterial thrombosis was observed. At the minimal observation period end point (3 months) all the patients survived without bleeding or new thrombotic event. Moreover, neither bleeding nor recurrence of HIT occurred during the total follow-up period. Conclusion Dabigatran is safe and efficient as first-line treatment for HIT and can be used as the only one anticoagulant in this challenging, clinical scenario. Funding Acknowledgement Type of funding sources: None.

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.

Influence of PAR-1 in patients with non-valvular atrial fibrillation: The antiplatelet effect of dabigatran

IntroductionDabigatran, a direct thrombin inhibitor, has been widely used in patients with non-valvular atrial fibrillation (NVAF) and is considered to have an antiplatelet effect. However, the mechanisms remain unclear. We evaluated protease-activated receptor-1 (PAR-1) expression and activation by thrombin on platelets from NVAF patients, before and after dabigatran treatment, in addition to the expression of platelet activation marker CD62P. Materials and methodsThe study included 18 NVAF patients. We used flow cytometry to measure the binding of PAR-1 monoclonal antibodies (SPAN12 and WEDE15) and the expression of CD62P with and without thrombin stimulation, before, 14 days after, and 28 days after treatment with dabigatran. Coagulation fibrinolysis markers were also measured. ResultsPAR-1 expression was significantly lower in NVAF patients than in healthy controls (HC); it was further reduced by thrombin stimulation. CD62P expression was almost absent on the platelets in NVAF patients, but was significantly increased by thrombin stimulation. PAR-1 expression was not significantly different before and after treatment; CD62P expression was inhibited by dabigatran. The levels of coagulation markers were significantly higher in NVAF patients than in HC, and decreased after treatment. ConclusionsLower expression of PAR-1 in NVAF patients resulted from the cleavage of PAR-1 on some platelets, by exposure to small amounts of thrombin in vivo. The therapeutic effect of dabigatran in NVAF patients was demonstrated by inhibition of CD62P expression on the platelet upon thrombin stimulation in vitro. Our results indicate that dabigatran may reveal antithrombotic activity with antiplatelet and anticoagulant effects.

Dabigatran reduces thrombin-induced neuroinflammation and AD markers in vitro: Therapeutic relevance for Alzheimer's disease.

Vascular risk factors such as atherosclerosis, diabetes, and elevated homocysteine levels are strongly correlated with onset of Alzheimer's disease (AD). Emerging evidence indicates that blood coagulation protein thrombin is associated with vascular and non-vascular risk factors of AD. Here, we examined the effect of thrombin and its direct inhibitor dabigatran on key mediators of neuro-inflammation and AD pathology in the retinoic acid (RA)-differentiated human neuroblastoma cell line SH-SY5Y. SH-SY5Y cells exposed to thrombin concentrations (10-100nM) +/- 250nM dabigatran for 24h were analyzed for protein and gene expression. Electrophoretic mobility shift assay (EMSA) was used to determine DNA binding of NFkB. Western blotting, qRT-PCR and ELISA were used to measure the protein, mRNA, and activity levels of known AD hallmarks and signaling molecules. Dabigatran treatment attenuated thrombin-induced increase in DNA binding of NFκB by 175% at 50nM and by 77% at 100nM thrombin concentration. Thrombin also augmented accumulation of Aβ protein expression and phosphorylation of p38 MAPK, a downstream molecule in the signaling cascade, expression of pro-apoptotic mediator caspase 3, APP, tTau and pTau. Additionally, thrombin increased BACE1 activity, GSK3β expression, and APP, BACE1, Tau and GSK3β mRNA levels. Co-incubation with dabigatran attenuated thrombin-induced increases in the protein, mRNA, and activities of the aforesaid molecules to various extents (between -31% and -283%). Our data demonstrates that thrombin promotes AD-related pathological changes in neuronal cultures and suggests that use of direct oral anticoagulants may provide a therapeutic benefit against thrombin-driven neuroinflammation and downstream pathology in AD.