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.

The Rise and Fall of Antithrombin Supplementation in Cardiac Surgery.

Various cohort studies, both retrospective and prospective, showed that low antithrombin levels after cardiac surgery (at the arrival in the intensive care unit and during the next days) were associated with a number of adverse outcomes, including surgical reexploration and thromboembolic events, eventually leading to prolonged stay in the intensive care. Values lower than 58% to 64% of antithrombin activity were indicative of this higher morbidity with good sensitivity and specificity. The scenario generated the hypothesis that low antithrombin levels needed to be corrected by supplementation to improve postoperative outcome. However, randomized controlled studies run to test this idea failed to demonstrate any benefit of antithrombin supplementation, showing no effects on outcome, neither as preemptive preoperative strategy nor for treating postoperative low antithrombin values. In addition, randomized trials highlighted that those patients who received antithrombin experienced significantly higher incidence of acute kidney injury with a pooled odds ratio of 4.41 (95% CI, 1.90-10.23; P = .001). A strongly decreased thrombin activity after antithrombin correction may eventually affect the efficiency of the glomerular filtration and cause the deterioration of kidney function, but underlying biological mechanisms remain unclear. In conclusion, low levels of antithrombin activity after cardiac surgery should be considered as a marker of greater severity of the patient's conditions and/or of the complexity of the surgical procedure. There are no indications for antithrombin supplementation in cardiac surgery unless for correcting heparin resistance.

Benefit Profile of Thrombomodulin Alfa Combined with Antithrombin Concentrate in Patients with Sepsis-Induced Disseminated Intravascular Coagulation.

Thrombomodulin alfa (TM-α, recombinant human soluble thrombomodulin) and antithrombin (AT) concentrate are anticoagulant agents for the treatment of disseminated intravascular coagulation (DIC). A post hoc analysis using data from 1198 patients with infection-induced DIC from the post-marketing surveillance of TM-α was conducted. To identify subgroups that benefit from combination therapy, the patients were a priori stratified into four groups by a platelet (Plt) count of 50 × 103/µL and plasma AT level of 50% (groups 1, 2, 3, and 4, with high Plt/high AT, high Plt/low AT, low Plt/high AT, and low Plt/low AT, respectively). Kaplan-Meier survival analysis showed significantly worse survival in groups 2 and 4 had than in group 1 (p = 0.0480, p < 0.0001, respectively), and multivariate analysis showed that concomitant AT concentrate was independently correlated with reduced 28-day mortality only in group 4 (hazard ratio 0.6193; 95% confidence interval, 0.3912-0.9805). The adverse drug reactions (ADRs) and bleeding ADRs were not different among the groups. Patients with both severe thrombocytopenia and AT deficiency are candidates for combined anticoagulant therapy with TM-α and AT concentrate.

A Suggested Link Between Antithrombin Dose and Rate of Recovery from Disseminated Intravascular Coagulation in Patients with Severe Organ Failure.

INTRODUCTION: The efficacy of antithrombin (AT) supplementation against septic disseminated intravascular coagulation (DIC) may depend on various pre-existing factors, particularly the AT dose and multiple organ dysfunction severity. This study aimed to identify the impactful factors for early DIC recovery. METHODS: Patients' clinical records, including AT therapy and septic DIC data, were retrospectively extracted from January 2015 to December 2020. The patients were divided into those with early DIC recovery (n = 34) and those without (n = 37). Multivariate logistic regression analysis determined significant independent factors. Time-to-event analysis confirmed how these factors affected the DIC recovery time. RESULTS: The AT dose per patient body weight (odds ratio [95% confidence interval]: 2.879 [1.031-8.042], P = 0.044) and pre-existing organ dysfunction severity (0.333 [0.120-0.920], P = 0.034) were significant independent factors affecting early DIC recovery. A higher AT dose significantly shortened the DIC recovery time among patients with severe organ dysfunction (P < 0.01), but not among non-severe patients (P = 0.855). CONCLUSION: The therapeutic efficacy of AT treatment for septic DIC might depend on the severity of pre-existing organ failure and the AT dose per patient body weight.

Management of DOAC in Patients Undergoing Planned Surgery or Invasive Procedure: Italian Federation of Centers for the Diagnosis of Thrombotic Disorders and the Surveillance of the Antithrombotic Therapies (FCSA) Position Paper.

Patients on anticoagulant treatment are constantly increasing, with an estimated prevalence in Italy of 2% of the total population. About a quarter of the anticoagulated patients require temporary cessation of direct oral anticoagulants (DOACs) or vitamin K antagonists for a planned intervention within 2 years from anticoagulation inception. Several clinical issues about DOAC interruption remain unanswered: many questions are tentatively addressed daily by thousands of physicians worldwide through an experience-based balancing of thrombotic and bleeding risks. Among possible valuable answers, the Italian Federation of Centers for the diagnosis of thrombotic disorders and the Surveillance of the Antithrombotic therapies (FCSA) proposes some experience-based suggestions and expert opinions. In particular, FCSA provides practical guidance on the following issues: (1) multiparametric assessment of thrombotic and bleeding risks based on patients' individual and surgical risk factor, (2) testing of prothrombin time, activated partial thromboplastin time, and DOAC plasma levels before surgery or invasive procedure, (3) use of heparin, (4) restarting of full-dose DOAC after high risk bleeding surgery, (5) practical nonpharmacological suggestions to manage patients perioperatively. Finally, FCSA suggests creating a multidisciplinary "anticoagulation team" with the aim to define the optimal perioperative management of anticoagulation.

Impact of different renal function equations on direct oral anticoagulant concentrations.

The purpose of this study is to investigate the correlation between glomerular filtration rate (GFR) estimated by different renal function equations and non-vitamin K antagonist oral anticoagulant concentration. Atrial fibrillation patients who aged ≥ 20 years and used dabigatran, rivaroxaban, or apixaban for thromboembolism prevention were enrolled to collect blood samples and measure drug concentrations using ultra-high-performance liquid chromatography with tandem mass spectrometry. The GFR was estimated using the Cockroft-Gault formula (abbreviated as creatinine clearance, CrCL), Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI) featuring both creatinine and cystatin C, and the Modification of Diet in Renal Disease Study equation (MDRD). Multivariate regression was used to investigate the associations of different renal function estimates with drug concentrations. A total of 511 participants were enrolled, including 146 dabigatran users, 164 rivaroxaban users and 201 apixaban users. Compared to clinical trials, 35.4% of dabigatran, 4.9% of rivaroxaban, and 5.5% of apixaban concentrations were higher than the expected range (p < 0.001). CKD-EPI and MDRD estimates classified fewer patients as having GFR < 50 mL/min than CrCL in all 3 groups. Both CrCL and CKD-EPI were associated with higher-than-expected ranges of dabigatran or rivaroxaban concentrations. Nevertheless, none of the renal function equations was associated with higher-than-expected apixaban concentrations. For participants aged ≥ 75 years, CKD-EPI may be associated with higher-than-expected trough concentration of dabigatran. In conclusion, CrCL and CKD-EPI both can be used to identify patients with high trough concentrations of dabigatran or rivaroxaban. Among elderly patients who used dabigatran, CKD-EPI may be associated with increased drug concentration.

Dabigatran for stroke prevention in real life in a sample of population from Turkey: D-SPIRIT registry.

OBJECTIVE: The D-SPIRIT registry is designed to investigate the safety and effectiveness of dabigatran etexilate in patients with atrial fibrillation in routine clinical practice. METHODS: D-SPIRIT is the first national, multicenter, prospective, observational, postmarketing registry that investigates the usage of dabigatran in real life. A total of 326 noveloral anticoagulant-eligible patients with atrial fibrillation who have been taking dabigatran etexilate therapy for stroke prevention at least 6 months from 9 different centers were enrolled into the registry. Patients were followed up for 2 years to evaluate the effectiveness and safety of the treatment. All adverse clinical events including bleeding, thromboembolic events, stroke, systemic embolism, transient ischemic attack, myocardial infarction, and all-cause death were recorded. RESULTS: The mean age was 71.1±9.6 years, and 57.4% of the study participants were female. The mean CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke or transient ischemic attack [TIA], vascular disease, age 65-74 years, sex category) score was 3.4±1.6. The cumulative adverse clinical events rate was 6.30% per year. The rate for embolic events including TIA, ischemic stroke, and peripheral embolism was 1.26% per year. The rate for major bleeding was 2.20% per year, and the mortality rate was 0.94% per year. CONCLUSION: This registry obtained an important overview of the current safety and effectiveness of the dabigatran etexilate in Turkey. Our results indicate similar rates of thromboembolic and bleeding events with pivotal phase 3 trial and other real-life registries. However, rate of undertreatment usage of dabigatran etexilate in real life was found to be considerable.

Patient perception and treatment convenience of dabigatran versus vitamin K antagonist when used for stroke prophylaxis in atrial fibrillation: Real-world Evaluation of Long-term Anticoagulant Treatment Experience (RE-LATE) study.

PURPOSE: Dabigatran is a direct thrombin inhibitor approved for stroke prophylaxis in patients with non-valvular atrial fibrillation (NVAF). Real-world data about patient preference, satisfaction and convenience in patients in Asia are not available. The study aimed to explore the perception of patients with newly diagnosed NVAF regarding dabigatran versus vitamin K antagonists (VKAs), when used for stroke prevention. PATIENTS AND METHODS: This was a multinational, multicentre, non-interventional study involving 49 sites across 5 countries in South East Asia and South Korea where 934 patients newly diagnosed with NVAF were initiated on either dabigatran (N=591) or VKA (N=343). Data were collected at baseline and over two follow-up visits across 6 months. Treatment satisfaction and patient convenience were evaluated using the Perception on Anticoagulant Treatment Questionnaire-2 (PACT-Q2). RESULTS: The mean age of the patients was 65.9±10.4 years, and 64.2% were male. Mean CHA2DS2-VASc score was 2.4±1.5, and mean HAS-BLED score was 1.2±0.9. At baseline, patients initiated on dabigatran had higher stroke risk, bleeding risk, creatinine clearance and proportion of patients with concomitant illnesses compared with patients initiated on VKAs. Treatment convenience was perceived to be significantly better with dabigatran versus VKAs at visits 2 and 3 (p=0.0423 and 0.0287, respectively). Treatment satisfaction was significantly better with dabigatran compared with VKAs at visit 3 (p=0.0300). CONCLUSION: In this study, dabigatran is associated with better patient perception in terms of treatment convenience and satisfaction compared with VKAs when used for stroke prevention in newly diagnosed NVAF patients from South East Asia and South Korea. TRIAL REGISTRATION NUMBER: NCT02849509. PLAIN LANGUAGE SUMMARY: Patient satisfaction with dabigatran versus VKAs in South East Asia. Patients with atrial fibrillation are at high risk of stroke and require anticoagulants for stroke prevention. Two such anticoagulants are dabigatran and VKAs. We wanted to compare the extent of satisfaction and treatment convenience among newly diagnosed patients with atrial fibrillation from the South East Asian region when they were given either dabigatran or VKAs. Consenting patients filled out a standardised questionnaire called the PACT-Q2 over three visits after they were started on either dabigatran (591 patients) or VKAs (343 patients). We found that satisfaction and convenience were significantly higher when patients received dabigatran than when they received VKAs.

Difference in left atrial D-dimer level in patients with atrial fibrillation treated with direct oral anticoagulant.

BACKGROUND: Atrial fibrillation (AF) may cause cerebral and systemic embolism. An increased D-dimer level indicates hyperactivation of secondary fibrinolysis, resulting in predilection for thrombosis. To clarify the differential effects of anticoagulation therapy, we compared the D-dimer levels in peripheral and left atrial (LA) blood of atrial fibrillation patients scheduled for ablation. METHODS: We analyzed 141 patients with non-valvular AF (dabigatran, n = 30; apixaban, n = 47; edoxaban, n = 64; mean age: 68 years, male: 60%). Peripheral venous blood and LA blood was collected before pulmonary vein isolation. We examined the laboratory and echocardiographic parameters. RESULTS: After adjusting for baseline characteristics, D-dimer level in the LA was significantly higher in patients treated with edoxaban than that in those on apixaban (0.77 ± 0.05 vs. 0.60 ± 0.05 µg/mL, P = 0.047), although there were no significant differences in peripheral D-dimer levels. We classified the D-dimer value of the LA into a normal group (< 0.9) and a high value group (≥ 1.0); the peripheral prothrombin fragment F1 + 2 level (odds ratio [OR] 1.012; 95% confidence interval [CI]: 1.003-1.022; P = 0.008) and left ventricular ejection fraction (LVEF) (OR, 0.947; 95% CI, 0.910-0.986; P = 0.008) were potential predictors of high LA D-dimer levels. CONCLUSIONS: In apixaban-treated patients, the D-dimer level in the left atrium was lower than in edoxaban-treated patients on the day of ablation, suggesting that the anticoagulant effect of apixaban on the left atrium is better than that of edoxaban in patients with AF.

A strategy of idarucizumab for pericardial tamponade during perioperative period of atrial fibrillation ablation.

OBJECTIVE: To investigate theoptimal idarucizumab (dabigatran antagonist) usage strategy for patients with acute pericardial tamponade receiving uninterrupted dabigatran during catheter ablation for atrial fibrillation (AF). METHODS: Ten patients presenting acute pericardial tamponade while receiving uninterrupted dabigatran during catheter ablation for AF in Beijing Anzhen Hospital from January 2019 to July 2020 were enrolled and retrospectively analyzed. A "wait and see" strategy of idarucizumab was carried out for all patients; in brief, idarucizumab was applied following pericardiocentesis, comprehensive evaluation of bleeding and hemostasis. RESULTS: There were five males, five paroxysmal AF, and the average age of the patients was 64.0 ± 9.8 years. Among the 10 patients, four were treated with dabigatran 110 mg, six were treated with dabigatran 150 mg, and one was simultaneously given clopidogrel. The average time from pericardial tamponade to the last dose of dabigatran was 8.2 ± 3.4 h. All patients underwent pericardiocentesis successfully, and the average drainage volume was 322.5 ml (220.0 ± 935.0 ml). For reversal anticoagulation, six patients received protamine, and five patients received idarucizumab. Of the five patients who were treated with idarucizumab, four presented exact hemostasis, except for one patient who underwent continuous drainage and finally received surgery repair. The average time to restart anticoagulation was 1.1 ± 0.3 days after the procedure, and no rebleeding, embolism or deaths were observed. CONCLUSION: The "wait and see" strategy of idarucizumab for acute pericardial tamponade during the perioperative period of catheter ablation for AF may be safe and feasible.

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.

Strategies for the prevention and treatment of bleeding in patients treated with dabigatran: an update.

INTRODUCTION: Although dabigatran is safer than vitamin K antagonists, bleeding still occurs. Bleeding is an important cause of short-term morbidity and rarely mortality and can also have long-term consequences that are often under-appreciated. After bleeding, patients often do not restart treatment or are poorly adherent, which is associated with increased thromboembolism and mortality. Consequently, we need strategies to prevent and treat bleeding in patients with atrial fibrillation treated with dabigatran. AREAS COVERED: We review a) relevant dabigatran pharmacology, b) the burden and consequences of bleeding, c) how to identify patients at high risk of bleeding; and d) existing and novel approaches to prevent and treat bleeding in dabigatran-treated patients. EXPERT OPINION: Concerns about the risk of bleeding associated with anticoagulant therapy and emerging evidence of increased risk of thromboembolism and mortality after bleeding highlight the need for improved approaches to prevention and treatment of bleeding. Future research priorities should focus on improving our ability to prevent bleeding by identifying modifiable risk factors and the development of safer agents. The current front runners include drugs that selectively target the contact pathway of coagulation (e.g. factor XI). Targeting upstream drivers of thrombosis (e.g. inflammation) could help to further reduce the risk of thromboembolism.

The Risk of Acute Kidney Injury with Oral Anticoagulants in Elderly Adults with Atrial Fibrillation.

BACKGROUND AND OBJECTIVES: Anticoagulation with either a vitamin K antagonist or a direct oral anticoagulant may be associated with AKI. Our objective was to assess the risk of AKI among elderly individuals with atrial fibrillation newly prescribed a direct oral anticoagulant (dabigatran, rivaroxaban, or apixaban) versus warfarin. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Our population-based cohort study included 20,683 outpatients in Ontario, Canada, ≥66 years with atrial fibrillation who were prescribed warfarin, dabigatran, rivaroxaban, or apixaban between 2009 and 2017. Inverse probability of treatment weighting on the basis of derived propensity scores for the treatment with each direct oral anticoagulant was used to balance baseline characteristics among patients receiving each of the three direct oral anticoagulants compared with warfarin. Cox proportional hazards regression was performed in the weighted population to compare the association between the prescribed anticoagulant and the outcomes of interest. The exposure was an outpatient prescription of warfarin or one of the direct oral anticoagulants. The primary outcome was a hospital encounter with AKI, defined using Kidney Disease Improving Global Outcomes thresholds. Prespecified subgroup analyses were conducted by eGFR category and by the percentage of international normalized ratio measurements in range, a validated marker of anticoagulation control. RESULTS: Each direct oral anticoagulant was associated with a significantly lower risk of AKI compared with warfarin (weighted hazard ratio, 0.65; 95% confidence interval, 0.53 to 0.80 for dabigatran; weighted hazard ratio, 0.85; 95% confidence interval, 0.73 to 0.98 for rivaroxaban; and weighted hazard ratio, 0.81; 95% confidence interval, 0.72 to 0.93 for apixaban). In the subgroup analysis, the lower risk of AKI associated with each direct oral anticoagulant was consistent across each eGFR strata. The risk of AKI was significantly lower among users of each of the direct oral anticoagulants compared with warfarin users who had a percentage of international normalized ratio measurements ≤56%. CONCLUSIONS: Direct oral anticoagulants were associated with a lower risk of AKI compared with warfarin.

An emulated target trial analysis based on Medicare data suggested non-inferiority of Dabigatran versus Rivaroxaban.

OBJECTIVES: Rivaroxaban and Dabigatran were the first two non-vitamin K antagonist oral anticoagulants (NOACs) for preventing stroke among non-valvular Atrial Fibrillation patients. This article aimed to evaluate the relative efficacy and safety of Rivaroxaban versus Dabigatran. STUDY DESIGN AND SETTING: An emulated target trial analysis was conducted based on Medicare, in which we constructed three "randomized clinical trials" with well-defined inclusion/exclusion criteria, treatment regimens, and analysis procedures. We analyzed the individual trials, examined temporal variations, and generated unified results via pooled analysis. RESULTS: With a two-year data collection window (2012-2013), 70,129 subjects were enrolled in the three emulated trials, with 36,269 and 34,089 in the Rivaroxaban and Dabigatran arms, respectively. Dabigatran (the reference group for hazard ratio - HR) was superior regarding time to any primary event (including ischemic stroke, other thromboembolic events, major bleeding, and death; HR 1.232, P-value 0.0025), major bleeding (HR 1.187, P-value <0.0001), and mortality (HR 1.488, P-value <0.0001). Differences regarding stroke and other thromboembolic events were not significant. CONCLUSION: Dabigatran was found as superior for the Medicare patients with multiple chronic conditions. Temporal variations, which had been largely neglected in the literature, were observed. This study may provide new insight into treating AF with NOACs.

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.

Meta-analysis comparing direct oral anticoagulants versus vitamin K antagonists in patients with left ventricular thrombus.

Current American College of Cardiology/American Heart Association guidelines for stroke or ST-elevation myocardial infarction recommend the use of oral vitamin K antagonists (VKAs) as a first-line anticoagulant. Although several studies have compared the use of direct oral anticoagulants (DOACs) to VKAs for left ventricular thrombus (LVT) anticoagulation therapy, they are small scale and have produced conflicting results. Thus, this meta-analysis was performed to aggregate these studies to better compare the efficacy and safety of DOACs with VKAs in patients with LVT. Cochrane Library, Google Scholar, MEDLINE, and Web of Science database searches through January 10, 2021 were performed. Eight studies evaluating stroke or systemic embolism (SSE), six studies for LVT resolution, and five studies for bleeding were included. There were no statistically significant differences in SSE (OR 0.89; 95% CI 0.46, 1.71; p = 0.73; I2 = 45%) and LVT resolution (OR 1.13; 95% CI 0.75, 1.71; p = 0.56; I2 = 1%) between DOAC and VKA (reference group) therapy. DOAC use was significantly associated with lower bleeding event rates compared to VKA use (OR 0.61; 95% CI 0.40, 0.93; p = 0.02; I2 = 0%). DOACs may be feasible alternative anticoagulants to vitamin K antagonists for LV thrombus treatment. Randomized controlled trials directly comparing DOACs with VKAs are needed.

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

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

Direct Oral Anticoagulants for Venous Thromboembolism Prophylaxis Following Robot-assisted Radical Cystectomy: A Retrospective Feasibility Study at a Single Academic Medical Center.

OBJECTIVES: To evaluate the use of direct oral anticoagulants following radical cystectomy for venous thromboembolism prophylaxis. We compared the experience of those who received venous thromboembolism prophylaxis following a robot-assisted radical cystectomy with either a direct oral anticoagulant or enoxaparin. METHODS: Medical records of 66 patients who underwent robot-assisted radical cystectomy between July 2017 and May 2020 at a single academic institution were reviewed retrospectively. Patients received extended prophylaxis with either a direct oral anticoagulant or enoxaparin before or following surgical discharge. Venous thromboembolic events and complications resulting in emergency department visits and readmissions were reviewed over a 90-day postoperative period. RESULTS: A total of 4 venous thromboembolic events within 90 days of surgery were observed. Among patients taking enoxaparin, 5% (2/37) developed a deep vein thrombosis and 3% (1/37) developed a pulmonary embolism. Among patients taking direct oral anticoagulants, 3% (1/29) developed a deep vein thrombosis. Zero patients in the enoxaparin group and 3% (1/29) of patients in the direct oral anticoagulant group experienced bleeding that required an emergency department visit. CONCLUSION: Direct oral anticoagulants performed comparably to enoxaparin in this feasibility study following robot-assisted radical cystectomy in 66 patients. No significant differences in the number of venous thromboembolisms or bleeding complications were observed. These data encourage future studies and support the prospect of direct oral anticoagulants as a potentially suitable oral alternative to injectable low molecular weight heparins for venous thromboembolism prophylaxis following radical cystectomy.