Structures and mechanisms of actin ATP hydrolysis.

The major cytoskeleton protein actin undergoes cyclic transitions between the monomeric G-form and the filamentous F-form, which drive organelle transport and cell motility. This mechanical work is driven by the ATPase activity at the catalytic site in the F-form. For deeper understanding of the actin cellular functions, the reaction mechanism must be elucidated. Here, we show that a single actin molecule is trapped in the F-form by fragmin domain-1 binding and present their crystal structures in the ATP analog-, ADP-Pi-, and ADP-bound forms, at 1.15-Å resolutions. The G-to-F conformational transition shifts the side chains of Gln137 and His161, which relocate four water molecules including W1 (attacking water) and W2 (helping water) to facilitate the hydrolysis. By applying quantum mechanics/molecular mechanics calculations to the structures, we have revealed a consistent and comprehensive reaction path of ATP hydrolysis by the F-form actin. The reaction path consists of four steps: 1) W1 and W2 rotations; 2) PG-O3B bond cleavage; 3) four concomitant events: W1-PO3- formation, OH- and proton cleavage, nucleophilic attack by the OH- against PG, and the abstracted proton transfer; and 4) proton relocation that stabilizes the ADP-Pi-bound F-form actin. The mechanism explains the slow rate of ATP hydrolysis by actin and the irreversibility of the hydrolysis reaction. While the catalytic strategy of actin ATP hydrolysis is essentially the same as those of motor proteins like myosin, the process after the hydrolysis is distinct and discussed in terms of Pi release, F-form destabilization, and global conformational changes.

Impact of perioperative low-molecular-weight heparin therapy on clinical events of elderly patients with prior coronary stents implanted > 12 months undergoing non-cardiac surgery: a randomized, placebo-controlled trial.

BACKGROUND: Little is known about the safety and efficacy of discontinuing antiplatelet therapy via LMWH bridging therapy in elderly patients with coronary stents implanted for > 12 months undergoing non-cardiac surgery. This randomized trial was designed to compare the clinical benefits and risks of antiplatelet drug discontinuation via LMWH bridging therapy. METHODS: Patients were randomized 1:1 to receive subcutaneous injections of either dalteparin sodium or placebo. The primary efficacy endpoint was cardiac or cerebrovascular events. The primary safety endpoint was major bleeding. RESULTS: Among 2476 randomized patients, the variables (sex, age, body mass index, comorbidities, medications, and procedural characteristics) and percutaneous coronary intervention information were not significantly different between the bridging and non-bridging groups. During the follow-up period, the rate of the combined endpoint in the bridging group was significantly lower than in the non-bridging group (5.79% vs. 8.42%, p = 0.012). The incidence of myocardial injury in the bridging group was significantly lower than in the non-bridging group (3.14% vs. 5.19%, p = 0.011). Deep vein thrombosis occurred more frequently in the non-bridging group (1.21% vs. 0.4%, p = 0.024), and there was a trend toward a higher rate of pulmonary embolism (0.32% vs. 0.08%, p = 0.177). There was no significant difference between the groups in the rates of acute myocardial infarction (0.81% vs. 1.38%), cardiac death (0.24% vs. 0.41%), stroke (0.16% vs. 0.24%), or major bleeding (1.22% vs. 1.45%). Multivariable analysis showed that LMWH bridging, creatinine clearance < 30 mL/min, preoperative hemoglobin < 10 g/dL, and diabetes mellitus were independent predictors of ischemic events. LMWH bridging and a preoperative platelet count of < 70 × 109/L were independent predictors of minor bleeding events. CONCLUSIONS: This study showed the safety and efficacy of perioperative LMWH bridging therapy in elderly patients with coronary stents implanted > 12 months undergoing non-cardiac surgery. An alternative approach might be the use of bridging therapy with half-dose LMWH. TRIAL REGISTRATION: ISRCTN65203415.

Structured benefit-risk assessment for enoxaparin, in the context of its label extension, for the extended treatment of deep vein thrombosis and pulmonary embolism, and prevention of its recurrence in patients with active cancer.

PURPOSE: Guidelines recommend low-molecular-weight heparins (LMWHs) for patients with cancer-associated thrombosis. However, until recently, only dalteparin and tinzaparin were approved in the European Economic Area (EEA) for these patients. This study compares the benefit-risk profile of enoxaparin with dalteparin and tinzaparin for the extended treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE), and prevention of recurrence in adult patients with active cancer. METHODS: A semi-quantitative structured benefit-risk assessment was conducted for the label-extension application of enoxaparin based on the benefit-risk action team descriptive framework: define decision context; determine key benefit and risk outcomes; identify data sources; extract data; interpret results. RESULTS: The key benefits were defined as reduced all-cause mortality and venous thromboembolism (VTE) recurrence (including symptomatic DVT, fatal PE or non-fatal PE); the key risks were major and non-major bleeding of clinical significance, and heparin-induced thrombocytopenia (HIT). Enoxaparin demonstrated comparable effects for the reduction of VTE recurrence and all-cause mortality versus other EEA-approved LMWHs (dalteparin, tinzaparin). There was no evidence of a significant difference between enoxaparin and the comparator groups with regard to incidence of major and non-major bleeding. The data on HIT were too limited to assess the difference between the two groups. CONCLUSIONS: The assessment demonstrated a favourable benefit-risk profile for enoxaparin similar to that of other EEA-approved LMWHs for the treatment of DVT and PE and the prevention of recurrence in patients with active cancer and thus supported the label-extension approval.

Apixaban for the Treatment of Venous Thromboembolism Associated with Cancer.

BACKGROUND: Recent guidelines recommend consideration of the use of oral edoxaban or rivaroxaban for the treatment of venous thromboembolism in patients with cancer. However, the benefit of these oral agents is limited by the increased risk of bleeding associated with their use. METHODS: This was a multinational, randomized, investigator-initiated, open-label, noninferiority trial with blinded central outcome adjudication. We randomly assigned consecutive patients with cancer who had symptomatic or incidental acute proximal deep-vein thrombosis or pulmonary embolism to receive oral apixaban (at a dose of 10 mg twice daily for the first 7 days, followed by 5 mg twice daily) or subcutaneous dalteparin (at a dose of 200 IU per kilogram of body weight once daily for the first month, followed by 150 IU per kilogram once daily). The treatments were administered for 6 months. The primary outcome was objectively confirmed recurrent venous thromboembolism during the trial period. The principal safety outcome was major bleeding. RESULTS: Recurrent venous thromboembolism occurred in 32 of 576 patients (5.6%) in the apixaban group and in 46 of 579 patients (7.9%) in the dalteparin group (hazard ratio, 0.63; 95% confidence interval [CI], 0.37 to 1.07; P<0.001 for noninferiority). Major bleeding occurred in 22 patients (3.8%) in the apixaban group and in 23 patients (4.0%) in the dalteparin group (hazard ratio, 0.82; 95% CI, 0.40 to 1.69; P = 0.60). CONCLUSIONS: Oral apixaban was noninferior to subcutaneous dalteparin for the treatment of cancer-associated venous thromboembolism without an increased risk of major bleeding. (Funded by the Bristol-Myers Squibb-Pfizer Alliance; Caravaggio ClinicalTrials.gov number, NCT03045406.).

Sex differences in thromboprophylaxis of the critically ill: a secondary analysis of a randomized trial.

PURPOSE: Venous thromboembolism (VTE) is a common complication of critical illness. Sex- or gender-based analyses are rarely conducted and their effect on outcomes is unknown. We assessed for an effect modification of thromboprophylaxis (dalteparin or unfractionated heparin [UFH]) by sex on thrombotic (deep venous thrombosis [DVT], pulmonary embolism [PE], VTE) and mortality outcomes in a secondary analysis of the Prophylaxis for Thromboembolism in Critical Care Trial (PROTECT). METHODS: We conducted unadjusted analyses using Cox proportional hazards analysis, stratified by centre and admission diagnostic category, including sex, treatment, and an interaction term. Additionally, we performed adjusted analyses and assessed the credibility of our findings. RESULTS: Critically ill female (n = 1,614) and male (n = 2,113) participants experienced similar rates of DVT, proximal DVT, PE, any VTE, ICU death, and hospital death. In unadjusted analyses, we did not find significant differences in treatment effect favouring males (vs females) treated with dalteparin (vs UFH) for proximal leg DVT, any DVT, or any PE, but found a statistically significant effect (moderate certainty) favouring dalteparin in males for any VTE (males: hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.52 to 0.96 vs females: HR, 1.16; 95% CI, 0.81 to 1.68; P = 0.04). This effect remained after adjustment for baseline characteristics (males: HR, 0.70; 95% CI, 0.52 to 0.96 vs females: HR, 1.17; 95% CI, 0.81 to 1.68; P = 0.04) and weight (males: HR, 0.70; 95% CI, 0.52 to 0.96 vs females: HR, 1.20; 95% CI, 0.83 to 1.73; P = 0.03). We did not identify a significant effect modification by sex on mortality. CONCLUSIONS: We found an effect modification by sex of thromboprophylaxis on VTE in critically ill patients that requires confirmation. Our findings highlight the need for sex- and gender-based analyses in acute care research.

RéSUMé: OBJECTIF: La maladie thromboembolique veineuse (MTEV) est une complication fréquente au cours des maladies critiques. Des analyses basées sur le sexe ou le genre sont rarement effectuées et leur effet sur les critères d'évaluation est inconnu. Nous avons évalué une modification de l'effet de la thromboprophylaxie (daltéparine ou héparine non fractionnée [HNF]) selon le sexe sur la maladie thrombotique (thrombose veineuse profonde [TVP], embolie pulmonaire [EP], MTEV) et sur les critères de mortalité au cours d'une analyse secondaire de l'étude PROTECT (essai de prophylaxie de la thromboembolie en soins critiques). MéTHODE: Nous avons réalisé des analyses non ajustées au moyen d'une analyse des risques proportionnels de Cox, stratifiées par site et catégorie diagnostique à l'admission, incluant le sexe, le traitement et un terme d'interaction. Nous avons aussi réalisé des analyses ajustées et avons évalué la crédibilité de nos constatations. RéSULTATS: Les participant·es dans un état critique de sexe féminin (n = 1 614) et masculin (n = 2 113) ont présenté des taux semblables de TVP, EP, et MTEV de tout type, de décès en soins intensifs et de décès en milieu hospitalier. Nous n'avons pas trouvé de différences significatives dans les analyses non ajustées en faveur des hommes (par rapport aux femmes) traités par la daltéparine (par rapport à l'HNF) pour la TVP de la cuisse, la TVP de tout type, ou tout type d'EP; en revanche, nous avons trouvé un effet statistiquement significatif (certitude modérée) en faveur de la daltéparine pour la MTEV de tout type (hommes : rapport de risque [RR], 0,71; intervalle de confiance [IC] à 95 %, 0,52 à 0,96 par rapport aux femmes : RR, 1,16; IC 95 %, 0,81 à 1,68; P = 0,04). Cet effet a persisté après ajustement pour les caractéristiques à l'inclusion (hommes : RR, 0,70; IC 95 %, 0,52 à 0,96 par rapport aux femmes : RR, 1,17; IC 95 %, 0,81 à 1,68; P = 0,04) et le poids (hommes : RR, 0,70; IC 95 %, 0,52 à 0,96 par rapport aux femmes : RR, 1,20; IC 95 %, 0,83 à 1,73; P = 0,03). Nous n'avons pas identifié de modification significative de l'effet en fonction du sexe sur la mortalité. CONCLUSION: Nous avons trouvé une modification de l'effet en fonction du sexe sur la thromboprophylaxie sur la MTEV chez les patient·es en état critique; cette constatation nécessite une confirmation. Nos constatations soulignent le besoin d'analyses en fonction du sexe et du genre dans la recherche sur les soins aigus.

Effectiveness of different antithrombotic agents in combination with tranexamic acid for venous thromboembolism prophylaxis and blood management after total knee replacement: a prospective randomized study.

BACKGROUND: Tranexamic acid (TXA) has been widely applied in total knee arthroplasty (TKA) to significantly reduce perioperative blood loss and improve knee function recovery in patients after surgery. The choice of antithrombotic agents for venous thromboembolism (VTE) prevention after TKA is controversial. Therefore, this study aimed to compare the effects of different antithrombotic agents on patients after primary unilateral TKA in the context of applied TXA. METHODS: A total of 180 patients undergoing primary unilateral TKA from October 2020 to December 2021 were included in this study. All patients were given an intraoperative drip of 60 mg/kg TXA. Thereafter, patients were divided into three groups (n = 60 each). Baseline data were comparable among the three groups. The average follow-up time was 3.02 ± 0.09 months. Group 1 enrolled patients receiving oral rivaroxaban (RA) at 10 mg, Group 2 included patients who received subcutaneous Dalteparin sodium at 2500 IU, while Group 3 included patients taking oral aspirin (ASA) at 100 mg. Patients in all the three groups received treatment once a day for 30 days at 12 h postoperatively. The primary outcomes in this study were post-treatment drainage volume and thrombotic complication rate. The secondary outcomes included hematologic parameters, transfusion rate, intraoperative blood loss, total blood loss (TBL), and bleeding complication rate. RESULTS: The average drainage volume after treatment was significantly lower in Group 3 than in Group 1 and Group 2 (205.2 ± 69.0 vs 243.4 ± 72.5 vs 295.4 ± 72.5 ml, P < 0.001), and there was a significant difference between Group 1 and Group 2 (243.4 ± 72.5 mL vs 295.4 ± 72.5 mL, P < 0.001). The blood transfusion rate of Group 2 dramatically increased compared with Group 1 and Group 3 (20.0% vs 6.7% vs 5.0%, P = 0.01). The bleeding complication rate in Group 1 apparently increased relative to Group 2 and Group 3 (26.7% vs 10.0% vs 8.3%, P = 0.008). Besides, there was no significant difference in the thrombotic complication rate among the three groups. CONCLUSION: Under the background of TXA application, ASA, RA, and Dalteparin sodium were all effective on preventing VTE after TKA. In addition, ASA effectively reduced post-treatment Hemoglobin (Hb) loss, drainage volume, TBL, transfusion rate, and bleeding complications compared with RA and Dalteparin sodium. TRIAL REGISTRATION: The trial was registered at the Chinese Clinical Trial Registry (ChiCTR2200060169). Date of Registration: 21/05/2022.

[Modern anticoagulation with factor Xa inhibitors in oncology: is the gastrointestinal bleeding rate (also) decisive?] / Moderne Antikoagulation mit FXa-Inhibitoren in der Onkologie: Ist die gastrointestinale Blutungsrate (mit)-entscheidend?

The increased risk of thrombosis and bleeding with an active tumor disease is known as the so-called "thrombo-hemorrhagic syndrome", which places high demands on anticoagulation. There are currently 4 randomized, prospective studies on the use of new, non-vitamin K dependent oral anticoagulants (NOAC) for the treatment of venous thromboembolism (VTE) that have occurred in oncology. The FXa inhibitors rivaroxaban, edoxaban and twice apixaban were each used in individual studies versus the standard therapeutic agent dalteparin. Since there is no direct head-to-head comparison of the FXa inhibitors mentioned within a study, the largest study - always compared to dalteparin - was evaluated for each NOAC. The studies were analyzed with regard to their effectiveness, safety, fatal bleeding rates, the risk of gastrointestinal bleeding (GIB) and other differences using descriptive statistics. With dalteparin, the mean VTE recurrence rate was approximately 9% over a 6-month treatment period. All three FXa inhibitors were not inferior to dalteparin in terms of potency. The VTE recurrence rate was - 2.3% lower in edoxaban and apixaban-treated patients and - 5.0% in rivaroxaban-treated patients. In terms of safety, there was an increased rate of severe bleeding (both + 2.4%) for rivaroxaban and edoxaban compared to dalteparin; in particular, the number of GIBs was significantly increased. In contrast, the number of severe bleeding was not increased for apixaban, as was the case for various bleeding types including GIB. In the Apixaban study, the overall rate of severe GIB, which accounted for about 50% of all severe bleeding, and that of clinically relevant non-severe bleeding, were the lowest. The FXa inhibitors are not inferior to the standard therapy with dalteparin in the VTE recurrence rate in oncological patients. The GIB rate appears to be an important predictive factor for the safety of this group of substances, so that tumor location, gastrointestinal risk factors and other individual criteria should be given greater consideration in future therapy decisions for or against an FXa inhibitor.

Evaluation of Low-Molecular-Weight Heparin for Treatment of Portal Vein Thrombosis in Liver Cirrhosis Patients.

Background and Objectives: Even though low-molecular-weight heparin (LMWH), including dalteparin, has a critical role in portal vein thrombosis (PVT) treatment in liver cirrhosis (LC) patients, the predictive factors and the proper dose of dalteparin for PVT treatment and relapse have not yet been investigated. Materials and Methods: This retrospective study evaluated the records of LC patients receiving dalteparin from July 2013 to June 2019. The odds ratio (OR) and adjusted OR were calculated from univariate and multivariable analyses, respectively. Results: Among data from 121 patients, the overall recanalization rate of all patients was 66.1% (80 patients). No history of variceal bleeding (OR 4.6, 95% CI: 1.88-11.43) and the case of newly developed thrombus before dalteparin treatment (OR 3.2, 95% CI: 1.24-8.08) were predictive factors associated with increased treatment response. Relapse of PVT occurred in 32 out of 80 patients (40%) who showed a recanalization. The risk of relapse was 3.1-3.9 times higher in those who took more than three months or more than six months from the diagnosis of PVT to dalteparin treatment compared to those who took less than these durations, respectively. In the dosing regimen, patients with the kg-based dosing regimen showed 2.6 times better response than those with the fixed dosing regimen. However, no difference in bleeding complications was observed. Conclusion: In the dosing regimen, the kg-based regimen that was the same as the venous thromboembolism regimen was a better option for the efficacy and safety of dalteparin therapy. Additionally, when treating PVT in LC patients, careful monitoring is recommended for patients with predictive factors for treatment response and relapse of PVT.

Efficacy and Safety of Apixaban versus Dalteparin as a Treatment for Cancer-Associated Venous Thromboembolism: A Systematic Review and Meta-Analysis.

Background and Objectives: Venous thromboembolism (VTE) is common in cancer patients. Anticoagulant therapy with low-molecular-weight heparins (LMWHs) and direct oral anticoagulants (DOACs), such as dalteparin and apixaban, have demonstrated efficacy and safety. However, more comparative research of these drugs is still needed. This study aimed to synthesize evidence on the efficacy of apixaban compared to dalteparin in reducing recurrent VTE, major bleeding, and clinically relevant non-major bleeding associated with cancer. Materials and Methods: We systematically searched the PubMed, Scopus, Web of Science, Embase, Cochrane Library, and ClinicalTrials databases up to 5 January 2023, for randomized controlled trials comparing apixaban versus dalteparin as treatment for cancer-associated VTE. Five studies were included. Effects according to meta-analyses were reported as relative risks (RRs) and their 95% confidence intervals (CIs). Results: It was found that 33 of 734 (4.5%) patients treated with apixaban and 56 of 767 (7.3%) with dalteparin had recurrent VTE as the efficacy outcome (RR 0.49, 95% CI 0.15-1.58, I2 38%). Major bleeding occurred in 25 of 734 patients treated with apixaban (3.4%) and 27 of 767 with dalteparin (3.5%) (RR 1.29, 95% CI 0.31-5.27, I2 59%). Likewise, clinically relevant non-major bleeding occurred in 64 of 734 patients treated with apixaban (8.7%) and 46 of 767 (5.9%) with dalteparin (RR 1.52, 95% CI 1.05-2.19, I2 0%). Conclusions: Apixaban showed a lower risk of recurrent VTE than dalteparin in patients with cancer-associated VTE, albeit with no statistical difference. Statistical significance was observed for no major clinically relevant bleeding but not for major bleeding.

The effects of three different low-molecular-weight heparins on blood loss after intramedullary nailing of trochanteric fractures.

PURPOSE: The purpose of this study was to compare the effects of reviparin, dalteparin and enoxaparin on intraoperative blood loss in patients with trochanteric fracture treated with intramedullary nailing. MATERIALS AND METHODS: This retrospective multicenter study included 100 patients with trochanteric fracture who were divided into three groups according to the low-molecular-weight heparin administered. In all cases, a short third generation Gamma nail was used for osteosynthesis. Complete blood count and number of red blood cell transfusions (RBC) were evaluated. RESULTS: The mean value of postoperative haemoglobin level was lower in the enoxaparin group compared to the reviparin group, with significant difference (p = 0.001; 95% CI 4.1-18.87). Patients in the dalteparin group received more RBC transfusions compared to the reviparin and enoxaparin group (p = 0.048). CONCLUSION: The use of enoxaparin and dalteparin in hip fracture patients can result in lower postoperative haemoglobin levels and more RBC transfusions compared to reviparin.

Glycan Mapping of Low-Molecular-Weight Heparin Using Mass Spectral Correction Based on Chromatography Fitting with "Glycomapping" Software.

In this work, the first version of "Glycomapping" software is developed for the analysis of the most common low-molecular-weight heparin (LMWH), enoxaparin. Using ultrahigh-performance liquid chromatography-mass spectrometry, size exclusion chromatography is applied, and a virtual database of glycans in enoxaparin is established for the initial searching. With "Glycomapping", a complex chromatogram can be fitted, significantly improving resolution and confirming an accurate distribution range for each size of glycan within enoxaparin. In addition, randomly matched MS data can be corrected, with the constraint of the corresponding chromatographic retention time range, to remove most false positive data. The analytical stability of "Glycomapping" software was confirmed. Enoxaparin, prepared by different manufacturers and from different animal sources, was analyzed using "Glycomapping." Compared to raw data, data processed with "Glycomapping" are more robust and accurate. Another two LMWHs, nadroparin and dalteparin could also be analyzed with this software. This work lays a solid foundation for the automated analysis of heterogeneous mixtures of natural glycans, such as LMWHs and other complex oligosaccharides and polysaccharides.

Intravitreal 5-Fluorouracil and Heparin to Prevent Proliferative Vitreoretinopathy: Results from a Randomized Clinical Trial.

PURPOSE: Proliferative vitreoretinopathy (PVR) is the major cause for surgical failure after primary rhegmatogenous retinal detachment (RRD). So far, no therapy has been proven to prevent PVR. Promising results for 5-fluorouracil (5-FU) and low-molecular weight heparin (LMWH) in high-risk eyes have been reported previously. The objective of this trial was to examine the effect of adjuvant intravitreal therapy with 5-FU and LMWH compared with placebo on incidence of PVR in high-risk patients with primary RRD. DESIGN: Randomized, double-blind, controlled, multicenter, interventional trial with 1 interim analysis. PARTICIPANTS: Patients with RRD who were considered to be at high risk for PVR were included. Risk of PVR was assessed by noninvasive aqueous flare measurement using laser flare photometry. METHODS: Patients were randomized 1:1 to verum (200 mg/ml 5-FU and 5 IU/ml dalteparin) and placebo (balanced salt solution) intravitreally applied during routine pars plana vitrectomy. MAIN OUTCOME MEASURES: Primary end point was the development of PVR grade CP (full-thickness retinal folds or subretinal strands in clock hours located posterior to equator) 1 or higher within 12 weeks after surgery. For grading, an end point committee assessed fundus photographs. Secondary end points included best-corrected visual acuity and redetachment rate. A group sequential design with 1 interim analysis was applied using the O'Brien and Fleming boundaries. Proliferative vitreoretinopathy grade CP incidence was compared using a Mantel-Haenszel test stratified by surgeon. RESULTS: A total of 325 patients in 13 German trial sites had been randomized (verum, n = 163; placebo, n = 162). In study eyes, mean laser flare was 31 ± 26 pc/ms. No significant difference was found in PVR rate. Primary analysis in the modified intention-to-treat population results were: verum 28% vs. placebo 23% (including not assessable cases as failures); odds ratio [OR], 1.25; 95% confidence interval [CI], 0.76-2.08; P = 0.77. Those in the per-protocol population were: 12% vs. 12%; OR, 1.05; 95% CI, 0.47-2.34; P = 0.47. None of the secondary end points showed any significant difference between treatment groups. During the study period, no relevant safety risks were identified. CONCLUSIONS: Rate of PVR did not differ between adjuvant therapy with 5-FU and LMWH and placebo treatment in eyes with RRD.

Renal function and clinical outcome of patients with cancer-associated venous thromboembolism randomized to receive apixaban or dalteparin. Results from the Caravaggio trial

The effect of renal impairment (RI) on risk of bleeding and recurrent thrombosis in cancer patients treated with direct oral anticoagulants for venous thromboembolism (VTE) is undefined. We ran a prespecified analysis of the randomized Caravaggio study to evaluate the role of RI as a risk factor for bleeding or recurrence in patients treated with dalteparin or apixaban for cancerassociated VTE. RI was graded as moderate (creatinine clearance between 30-59 mL/minute; 275 patients) and mild (between 60- 89 mL/minute; 444 patients). In the 1142 patients included in this analysis, the incidence of major bleeding was similar in patients with moderate vs. no or mild RI (HR 1.06-95% CI: 0.53-2.11), with no difference in the relative safety of apixaban and dalteparin. Recurrent VTE was not different in moderate vs. no or mild RI (HR=0.67, 95% CI: 0.38-1.20); in moderate RI, apixaban reduced recurrent VTE compared to dalteparin (HR=0.27, 95% CI: 0.08-0.96; P for interaction 0.1085). At multivariate analysis, no association was found between variation of renal function over time and major bleeding or recurrent VTE. Advanced or metastatic cancer was the only independent predictor of major bleeding (HR=2.84, 95% CI: 1.20-6.71), with no effect of treatment with apixaban or dalteparin. In our study, in cancer patients treated with apixaban or dalteparin, moderate RI was not associated with major bleeding or recurrent VTE. In patients with moderate renal failure, the safety profile of apixaban was confirmed with the potential for improved efficacy in comparison to dalteparin. ClinicalTrials.gov identifier: NCT03045406.

Effects of dalteparin on anti-Xa activities cannot be predicted in critically ill COVID-19 patients.

Critically ill COVID-19 patients are at high risk of thromboembolic events despite routine-dosed low-molecular-weight heparin thromboprophylaxis. However, in recent randomized trials increased-intensity thromboprophylaxis seemed futile and possibly even harmful. In this explorative pharmacokinetic (PK) study we measured anti-Xa activities on frequent timepoints in 15 critically ill COVID-19 patients receiving dalteparin and performed PK analysis by nonlinear mixed-effect modelling. A linear one-compartment model with first-order kinetics provided a good fit. However, wide interindividual variation in dalteparin absorption (variance 78%) and clearance (variance 34%) was observed, unexplained by routine clinical covariates. Using the final PK model for Monte Carlo simulations, we predicted increased-intensity dalteparin to result in anti-Xa activities well over prophylactic targets (0.2-0.4 IU/mL) in the majority of patients. Therapeutic-intensity dalteparin results in supratherapeutic anti-Xa levels (target 0.6-1.0 IU/mL) in 19% of patients and subtherapeutic levels in 22%. Therefore, anti-Xa measurements should guide high-intensity dalteparin in critically ill COVID-19 patients.

A phase 2 pharmacodynamic dose-finding, safety, and efficacy study of dalteparin for pediatric venous thromboembolism treatment in children with and without cancer.

Data from registrational trials of pediatric venous thromboembolism (VTE) treatment are sparse, especially among cancer patients. We conducted a prospective, multicenter, open-label trial (NCT00952380) on dose-finding, safety, and efficacy (measured by 90-day risks of clinically relevant bleeding [CRB] and symptomatic recurrent VTE [srVTE]) of twice-daily subcutaneous dalteparin for acute VTE treatment in patients ≤18 years old. Among 38 patients (cancer, n = 26; noncancer, n = 12), median dalteparin dose requirements per kilogram varied with age but not cancer status. Risks of CRB and srVTE were <4% in cancer and noncancer subgroups. Dalteparin is an important FDA-approved treatment for pediatric VTE, particularly with cancer.

Trends in post-discharge prophylactic anticoagulant use among stroke patients in the United States between 2006 and 2019.

BACKGROUND: Stroke is an independent risk factor for venous thromboembolism (VTE). Although the risk of VTE persists after hospital discharge, information on the utilization of anticoagulants among stroke patients after discharge remains limited. OBJECTIVE: To evaluate changes in post-discharge thromboprophylaxis among stroke patients between 2006 and 2019. METHODS: We conducted a retrospective repeated cross-sectional analysis using a commercial healthcare insurance database in the United States. We included patients aged ≥ 18 years with incident stroke diagnosis and assessed prophylactic use of anticoagulants in the 30 days following hospital discharge including low-molecular-weight heparin (enoxaparin ≤40 mg/day, dalteparin ≤5000 IU/day), unfractionated heparin ≤5000 IU/ twice daily or 3 times a day, apixaban 2.5 mg twice daily, and rivaroxaban 10 mg/day. Patients with atrial fibrillation, VTE, mechanical heart valves, cancer, antiphospholipid antibody syndrome, and users of therapeutic doses of anticoagulants were excluded. We used the Cochrane-Armitage test to assess changes in the use of anticoagulants across the study period. RESULTS: There was a small increase in the overall use of post-discharge prophylactic anticoagulants among stroke patients between 2006 and 2019 from 0.5% to 1.9%. The use of heparin decreased from 0.5% in 2006 to 0.3% in 2019 (P-value for trend = 0.001). In contrast, the use of apixaban or rivaroxaban increased from 0.1% in 2013 to 1.6% in 2019 (P-value for trend < 0.001). Apixaban was more commonly used than rivaroxaban. CONCLUSIONS: In this population-based study of stroke patients, we found that post-discharge anticoagulant use remains low through 2019. Prophylactic use of heparin or rivaroxaban was relatively low but the use of apixaban increased over the study period. Further research is needed to determine if these agents are safe and effective for VTE prevention in stroke patients.

Edoxaban for the Treatment of Cancer-Associated Venous Thromboembolism.

BACKGROUND: Low-molecular-weight heparin is the standard treatment for cancer-associated venous thromboembolism. The role of treatment with direct oral anticoagulant agents is unclear. METHODS: In this open-label, noninferiority trial, we randomly assigned patients with cancer who had acute symptomatic or incidental venous thromboembolism to receive either low-molecular-weight heparin for at least 5 days followed by oral edoxaban at a dose of 60 mg once daily (edoxaban group) or subcutaneous dalteparin at a dose of 200 IU per kilogram of body weight once daily for 1 month followed by dalteparin at a dose of 150 IU per kilogram once daily (dalteparin group). Treatment was given for at least 6 months and up to 12 months. The primary outcome was a composite of recurrent venous thromboembolism or major bleeding during the 12 months after randomization, regardless of treatment duration. RESULTS: Of the 1050 patients who underwent randomization, 1046 were included in the modified intention-to-treat analysis. A primary-outcome event occurred in 67 of the 522 patients (12.8%) in the edoxaban group as compared with 71 of the 524 patients (13.5%) in the dalteparin group (hazard ratio, 0.97; 95% confidence interval [CI], 0.70 to 1.36; P=0.006 for noninferiority; P=0.87 for superiority). Recurrent venous thromboembolism occurred in 41 patients (7.9%) in the edoxaban group and in 59 patients (11.3%) in the dalteparin group (difference in risk, -3.4 percentage points; 95% CI, -7.0 to 0.2). Major bleeding occurred in 36 patients (6.9%) in the edoxaban group and in 21 patients (4.0%) in the dalteparin group (difference in risk, 2.9 percentage points; 95% CI, 0.1 to 5.6). CONCLUSIONS: Oral edoxaban was noninferior to subcutaneous dalteparin with respect to the composite outcome of recurrent venous thromboembolism or major bleeding. The rate of recurrent venous thromboembolism was lower but the rate of major bleeding was higher with edoxaban than with dalteparin. (Funded by Daiichi Sankyo; Hokusai VTE Cancer ClinicalTrials.gov number, NCT02073682 .).

Long-term follow-up of portal vein thrombosis in an American Cocker Spaniel with lobular dissecting hepatitis: a case report.

BACKGROUND: Lobular dissecting hepatitis (LDH) is a rare form of canine liver cirrhosis that may be accompanied by portal hypertension in American Cocker Spaniels. In human patients with liver cirrhosis, portal vein thrombosis (PVT) is a common complication. However, PVT has not been reported in dogs with LDH. Herein, we describe the long-term follow-up of PVT in an American Cocker Spaniel with LDH. CASE PRESENTATION: An 8-year-old neutered male American Cocker Spaniel presented with a 1-month history of severe abdominal effusion. The dog was histopathologically diagnosed with LDH and treated with low-dose prednisolone on day 14. On day 115, computed tomography angiography (CTA) confirmed the presence of a thrombus in the portal vein. Therefore, the dog was subcutaneously administered with the anticoagulant dalteparin, and low-dose prednisolone was continued. As a follow-up for PVT, CTA examinations were performed on days 207, 515, 886, and 1168, and the dog's antithrombin and D-dimer levels were measured. Following anticoagulant therapy, the dog was confirmed to have gradually increased antithrombin activity and decreased D-dimer concentrations. In addition, although the thrombus was confirmed to be in the same area of the portal vein system by CTA, atrophy and increased CT values due to organization were observed during the follow-up period. The dog's condition remained stable without clinical signs until day 1112 when it developed hepatic encephalopathy. The dog died on day 1208. On postmortem examination, histopathologically, the liver showed marked bile duct hyperplasia and fibrosis with chronic thrombus in the portal vein. CONCLUSIONS: This case demonstrated that low-dose glucocorticoid combined with dalteparin allowed long-term follow-up of PVT in an American Cocker Spaniel with LDH.

Effect of low-molecular-weight heparins on anti-Xa peak levels and adverse reactions in Chinese patients with recurrent spontaneous abortion: a single-center, observational study.

OBJECTIVE: To compare three commonly used low-molecular-weight heparins (LWMHs) in the treatment of recurrent spontaneous abortion (RSA) by evaluating the anti-Xa peak levels and adverse reactions. METHODS: In this single-center, observational study, we enrolled 310 patients with RSA in whom anti-Xa levels were measured during pregnancy. Patients were divided into three groups according to the LMWH they used: the nadroparin group, enoxaparin group and dalteparin group. We compared the peak anti-Xa levels and the coagulation status of each group, and analyzed the incidence of adverse reactions, including local allergy, liver and renal dysfunction, and the impact on platelet. RESULTS: Patients in the enoxaparin group had a higher anti-Xa peak level than those in the nadroparin group (0.80 ± 0.22 IU/ml vs. 0.61 ± 0.24 IU/ml; P <  0.0001), although most patients in the three groups reached the target concentration of anti-Xa. Furthermore, patients in the enoxaparin group had a more stable anti-Xa levels during pregnancy. In addition, patients in the nadroparin group had a higher rate of local allergy than those in the enoxaparin group (60.5% vs. 42.5%; P = 0.004) and those in the dalteparin group (60.5% vs. 33.3%; P = 0.002). Further examination by the type of local allergy indicated a dramatic difference in pruritus and induration between the nadroparin group and the other two groups. No difference was found in the incidence of liver and renal dysfunction and thrombocytopenia. CONCLUSION: Compared with nadroparin and daltepatin, enoxaparin showed a better performance regarding anti-Xa levels and the incidence of adverse reactions in the treatment of RSA.

A single-centre, prospective cohort study of COVID-19 patients admitted to ICU for mechanical ventilatory support.

BACKGROUND: Mortality rates in COVID-19 patients in need of mechanical ventilation are high, with wide variations between countries. Most studies were retrospective, and results may not be generalizable due to differences in demographics, healthcare organization and surge capacity. We present a cohort of mechanically ventilated COVID-19 patients from a resource-rich, publicly financed healthcare system. METHODS: Prospective study from a tertiary hospital. Consecutive SARS-CoV-2 positive adult patients admitted to the ICU for mechanical ventilation from 10 March 2020 to 04 May 2020 were included. Triage and treatment were protocolized. High-dose dalteparin was adjusted by D-dimer. Demographics, treatments and high-resolution physiological variables were collected. Outcomes were 30-day and hospital mortality. Data are medians (quartiles). RESULTS: Of the 1484 persons in the hospital catchment area testing positive for SARS-CoV-2, 201 (13.5%) were hospitalized. Thirty-eight (19%) patients were mechanically ventilated, of whom five (13%) died. Of the 163 patients treated with supplemental oxygen, eight (5%) died. In ventilated patients (75% males, age 61 (53-70) years), severe, moderate and mild ARDS was present in 25%, 70% and 5%. Tidal volume ≤8 mL/kg ideal bodyweight was achieved in 34 (94%) patients. Proning and neuromuscular blockers were used in 19 (54%) and 20 (61%) patients. Duration of ventilation was 12 days (8-23). D-dimer peaked at 3.8 mg/L (2.1-5.3), and maximum dalteparin dose was 15 000 IU/24 h (10 000-15 000). Despite organizational changes, a high degree of adherence to treatment protocols was achieved. CONCLUSION: In a prospective cohort study of mechanically ventilated COVID-19 patients treated in a resource-rich, publicly financed healthcare system, mortality was considerably lower than previously reported in retrospective studies.