Low Molecular Weight Heparin Enoxaparin Research Articles

Real-world comparative effectiveness of dalteparin and enoxaparin for venous thromboembolism prophylaxis.

Venous thromboembolism (VTE) is a preventable cause of significant morbidity and mortality in hospitalized patients world-wide. In Australia, the low-molecular weight heparins (LMWHs) enoxaparin or dalteparin are usually used as first-line prophylaxis for VTE, though there is uncertainty whether dalteparin has the same effectiveness as enoxaparin in real-world settings. This is relevant because dalteparin is less renally cleared and may be more cost effective than enoxaparin. The aim of this study was to explore VTE event incidence in a general cohort of hospitalized adult inpatients who were prescribed enoxaparin or dalteparin for VTE prophylaxis. A retrospective observational study was conducted at a quaternary hospital in Brisbane, Australia, of patients who had experienced a hospital-acquired VTE from 1 September 2021 to 1 March 2023. Patients were identified from routinely collected data following an in-hospital VTE event, and further data was retrieved retrospectively from the integrated electronic Medical Record (ieMR). Incidence and type of VTE events, LMWH-prescribing patterns, and risk factors were assessed. The incidence of VTE events were similar across the dalteparin and enoxaparin cohorts (42.1 events/10 000 patients vs. 34.4 events/10 000 patients, respectively), although patients prescribed enoxaparin had a higher number of risk factors, particularly obesity and active cancer. Our research indicates comparable incidence of VTE in patients prescribed dalteparin compared with enoxaparin in an Australian hospital general cohort of adult inpatients. Dalteparin may be as effective as enoxaparin for VTE prophylaxis in a real-world cohort of patients, and as such dalteparin may be considered a suitable alternative to enoxaparin for VTE prophylaxis. Further research including large randomized controlled trials are required to confirm these results.

Thromboprophylaxis with Intermediate Dose Low Molecular Weight Heparin in Adults Undergoing Induction with L-Asparaginase for Acute Lymphoblastic Leukemia

Introduction Adolescents and young adults (AYA, defined as age 15-39 years) with acute lymphoblastic leukemia (ALL) have a poorer prognosis than their pediatric counterparts. To replicate the success of ALL treatment in children, pediatric-inspired regimens have been incorporated into the treatment of AYA and often include the use of L-asparaginase. Rates of thrombosis in adults receiving L-asparaginase for treatment of ALL have been reported to be as high as 34%, compared to only about 5% in pediatric patients. The risk of thrombosis is elevated primarily during the induction phase of treatment. Several strategies have been studied in adults, including antithrombin III replacement, fresh frozen plasma replacement, and prophylactic dosing of anticoagulation, however no clear guidelines exist on how to prevent thrombosis in these high-risk patients. To prevent L-asparaginase-induced thrombotic events, our institution implemented a standard practice of 1mg/kg/day of low molecular weight heparin (LMWH), a dose in-between prophylactic and therapeutic dosing, administered to all adults with ALL who were treated with L-asparaginase during induction chemotherapy. In this current study, we report data from patients who have been treated with this strategy from 2012 to present, focusing on the antithrombotic efficacy and safety of 1mg/kg/day LMWH in this population. Methods This retrospective chart review included 62 patients who received prophylactic anticoagulation with the LMWH enoxaparin (1mg/kg/day) while undergoing induction chemotherapy with L-asparaginase for ALL at the Oregon Health & Science University from 2012 to present. Anticoagulation with enoxaparin was initiated with the first dose of L-asparaginase and continued until the day of discharge or day 30 of induction. The primary outcome was the incidence of thrombosis within the first 30 days of L-asparaginase administration. Minor and major bleeding events, as defined by the International Society of Thrombosis and Haemostasis (ISTH), were recorded. Statistical analysis with univariate regression models was performed to evaluate the association of thrombotic events with demographic, disease and treatment variables. Results Sixty-two patients received 1mg/kg/day LMWH prophylaxis during ALL induction between January 2012 and June 2023 (43 with B-ALL and 19 with T-ALL). Median age at induction was 25.7 years (range 18-39 years). A majority of patients (83.9%) received the maximum dose of 2500mg/m 2 of L-asparaginase. Four patients (6.5%; 95% CI 1.8%-15.7%) experienced a thrombotic event within the first 30 days of induction with L-asparaginase; 3 of the events were catheter-associated and were treated supportively or with catheter removal, and 1 patient developed a distal lower extremity deep vein thrombosis related to myositis. Median time to thrombosis was 13.5 days (range 11-22 days). There were no significant associations between development of thrombotic events with age, gender, B- or T-cell precursor, or dose of L-asparaginase. No thrombosis-related deaths or major bleeding events occurred. Conclusions Prophylactic anticoagulation with intermediate dose 1mg/kg/day LMWH in adults with ALL undergoing induction chemotherapy with L-asparaginase is a safe and an effective strategy to prevent serious thrombotic events. Our institutional rate of 6.5% of patients experiencing thrombotic events during induction with L-asparaginase, with all of the events being clinically low risk, compares favorably to historically reported rates in adults and approaches the low rates reported in children. Further prospective research is warranted.

Abstract 12787: Efficacy and Safety of Apixaban versus Low Molecular Weight Heparin for the Treatment of Venous Thromboembolism in Cancer Patients: A Systematic Review and Meta-Analysis

Introduction: Current guidelines recommend the use of low molecular weight heparin (LMWH) for the management of venous thromboembolism (VTE) in cancer patients. However, direct oral anticoagulants (DOACs) have emerged as promising alternative for reducing VTE events. Moreover, apixaban shows a higher safety profile among DOACs. Hypothesis: This study aims to compare the efficacy and safety of apixaban versus LMWH (Enoxaparin or Dalteparin) in the treatment of venous thromboembolism in cancer patients. Methods: A systematic search was conducted in electronic databases (Pubmed, Embase, Scopus, and Cochrane libraries) from inception until June 2023, using appropriate Mesh terms for ‘apixaban’, ‘LMWH’, and ‘VTE’. Pooled risk ratios (RR) with their corresponding 95% confidence intervals (CI) were calculated using random effects models. A p-value of <0.005 was considered statistically significant. Results: Five randomized trials involving 2311 patients (apixaban: 1088 and LMWH: 1223) with mean ages of 64.5±11.45 and 64.2±10.8, respectively, were included in the analysis. At a median follow-up of six months, the occurrence of clinically relevant non-major bleeding (CRNMB) (OR, 1.04, 95% CI: 0.66 - 1.64, I2=37.72%, p=0.87), composite of major and CRNMB (OR, 1.11, 95% CI: 0.84 - 1.46, I2=0.00%, p=0.47), were higher with apixaban treatment. However, the rates of recurrent VTE (OR, 0.72, 95% CI: 0.50 - 1.04, I2=3.91%, p=0.08), major bleeding (OR, 0.83, 95% CI: 0.55 - 1.25, I2=0.00%, p=0.38), and mortality (OR, 0.91, 95% CI: 0.79 - 1.05, I2=0.00%, p=0.19) were lower with apixaban compared to LMWH treatment. However, none of the observed differences reached statistical significance. Conclusions: In cancer patients with VTE, apixaban demonstrates non-inferior efficacy and a comparable safety profile to LMWH. Further randomized trials are warranted to confirm these findings.

Tolerability of Direct Oral Anticoagulants and Low Molecular Weight Heparin in Patients with Brain Tumors or CNS Metastases

Background: Despite the increase in the use of direct oral anticoagulants (DOACs) for cancer-associated thrombosis, limited data exists regarding the safety of DOACs in patients with brain metastases or primary brain tumors. The purpose of this retrospective cohort study is to describe overall tolerability of DOACs compared to low-molecular weight heparin (LMWH) for the treatment of venous thromboembolism (VTE) or for stroke prevention in atrial fibrillation (AF), in patients with brain tumors or CNS metastases. Methods: This is a single center, institutional review board approved retrospective cohort study at New York University Langone Health of patients with primary brain tumors or CNS metastasis that received therapeutic dosed anticoagulation with either a DOAC or LMWH (enoxaparin) between December 1, 2018 and August 19, 2022. Electronic medical records were reviewed for pertinent data. The primary outcome was tolerability of anticoagulation, which included continuation of initial anticoagulation therapy and absence of any switches in anticoagulation, dose adjustments or temporary interruptions. Reasons for discontinuations included bleeding events, intolerance/patient preference (such as the need for subcutaneous administration or cost of therapy), provider preference, or a change in clinical status such as transition to hospice or unable to determine based on chart review. Secondary outcomes included the incidence of anticoagulation discontinuations secondary to an intracerebral hemorrhage (ICH). Results: A total of 153 patients were included (DOAC n = 105, 69%; enoxaparin n = 48, 31%). The study population was predominantly White (74%), male (59%), with a median BMI≥30 kg/m2 in 40% of the cohort and age of 65 (IQR 56-73) years; however, the enoxaparin group was younger than the DOAC group at 59.5 years vs. 67 years (p <0.001), respectively at the time of anticoagulation initiation. Primary brain tumors were the most prevalent in the total cohort at 89%, with enoxaparin most commonly prescribed at 71% versus a DOAC at 47%, p = 0.005. Other primary malignancies included anaplastic astrocytoma, glioma, anaplastic oligodendroglioma, and tanycytic ependymoma. Non-small cell lung cancer was the most common malignancy that resulted in CNS metastasis (7.2%). The most common indication for anticoagulation was for the treatment of VTE at 70%, followed by stroke prevention in AF at 28%, with the remainder 2% as off-label. The primary outcome of remaining on initial anticoagulant chosen without any anticoagulant therapy changes occurred in only 52% of the cohort. There were more changes in therapy in the enoxaparin cohort at 29, 60% vs. 44, 42% for the DOAC cohort, p = 0.033, driven by provider preference in 48% of the cohort and patient intolerance in 29% of the cohort. More patients in the enoxaparin cohort were switched to a DOAC (n = 17) and more patients in the DOAC cohort had their initial anticoagulation discontinued for non- ICH reasons (n = 14). The median time to any anticoagulation switch was 2.12 months (IQR 0.35-4.27 months). Discontinuations in patients who were still alive was primarily driven by completion of therapy, deemed by the treatment team, intolerance or patient preference, and provider preference (Table 1). Though the reason for provider preference was not always clearly elucidated upon chart review, this trend supports the movement towards increasing DOAC use. The secondary outcome of the incidence of ICH was also lower in the DOAC cohort compared to enoxaparin at 3.8 vs 14.6% (p = 0.037). (Figure 1) Conclusions: Our study demonstrates real world prescribing practice of anticoagulants for the treatment of VTE or stroke prevention in AF in patients with primary brain tumors or metastases. Although initial anticoagulants chosen were either discontinued or switched to an alternative agent, we observed a shift towards a preference for DOACs, similar to the shift towards DOACs for cancer associated thrombosis. We also observed a lower incidence of ICH with DOACs compared to LMWH. However, these results should be confirmed in a randomized controlled trial to account for the inherent selection biases we could not account for, which may have favored the initial anticoagulant chosen, the reason for switch, and overall tolerability.

Anti-factor Xa level monitoring of low-molecular-weight heparin for prevention of venous thromboembolism in critically ill patients (AXaLPE): protocol of a randomised, open-label controlled clinical trial

IntroductionWhether and when to monitor the amount of anti-factor Xa (aFXa) activity in critically ill patients with complex diseases to prevent venous thromboembolism (VTE) remain unclear. This study is a...

Effect of low-molecular-weight heparin on placenta-mediated fetal growth restriction in a tertiary referral hospital: A 7-year retrospective cohort study.

To investigate the effect of low-molecular-weight heparin (LMWH) on placenta-mediated fetal growth restriction (FGR). A cohort of 570 pregnant women diagnosed with placenta-mediated FGR were enrolled from January 1, 2015 through to December 31, 2021. A birth database, including demographic data, antenatal complications, and detailed delivery and newborn data, was created to collect variables from the Hospital Information System (HIS) Database. The unique personal registration number, assigned to each patient on first registration with HIS in the West China Second University Hospital, was used to link these patients. LMWH use was defined as at least 1-week prescription from diagnosis of placenta-mediated FGR. Pregnant women received LMWH (Enoxaparin 4000 IU/day) by self-administered subcutaneous injection only when they agreed and signed informed consent. Primary outcome was intrauterine fetal death after 20 weeks of pregnancy. Secondary outcomes included preterm birth (PB), Apgar score less than 7 at 1 min, admission to neonatal intensive care unit (NICU), and birth weight. Logistic regression analysis was conducted to compute adjusted odds ratio (aOR) with 95% confidence intervals (CI) for outcomes. After controlling for confounders, LMWH use was associated with a decreased risk of intrauterine fetal death (aOR 2.49, 95% CI 1.35-4.57, P = 0.003), PB before 37 weeks of pregnancy (aOR 3.35, 95% CI 2.14-5.23, P < 0.001), PB before 34 weeks of pregnancy (aOR 2.25, 95% CI 1.36-3.74, P = 0.002), Apgar score less than 7 at 1 min (aOR 2.25, 95% CI 1.36-3.74, P = 0.002), NICU admission (aOR 2.29, 95% CI 1.48-3.55, P < 0.001). Using LMWH increased the mean birth weight in PB before 32 weeks of pregnancy (mean ± standard deviation [SD] 1126.4 ± 520.0 g, P = 0.020), PB before 37 weeks of pregnancy (mean ± SD 1563.9 ± 502.7 g, P = 0.019), early-onset FGR (mean ± SD 2125.2 ± 665.7 g, P < 0.001), late-onset FGR (mean ± SD 2343.4 ± 507.9, P < 0.001), and non-severe FGR (mean ± SD 2231.1 ± 607.2 g, P < 0.001). Use of LMWH can significantly improve the fetal and neonatal outcomes among pregnant women with placenta-mediated FGR, particularly reducing the risk of intrauterine fetal death.

Venous Thromboembolism Prophylaxis in Major Orthopedic Surgeries and Factor XIa Inhibitors.

Venous thromboembolism (VTE), comprising pulmonary embolism (PE) and deep vein thrombosis (DVT), poses a significant risk during and after hospitalization, particularly for surgical patients. Among various patient groups, those undergoing major orthopedic surgeries are considered to have a higher susceptibility to PE and DVT. Major lower-extremity orthopedic procedures carry a higher risk of symptomatic VTE compared to most other surgeries, with an estimated incidence of ~4%. The greatest risk period occurs within the first 7-14 days following surgery. Major bleeding is also more prevalent in these surgeries compared to others, with rates estimated between 2% and 4%. For patients undergoing major lower-extremity orthopedic surgery who have a low bleeding risk, it is recommended to use pharmacological thromboprophylaxis with or without mechanical devices. The choice of the initial agent depends on the specific surgery and patient comorbidities. First-line options include low-molecular-weight heparins (LMWHs), direct oral anticoagulants, and aspirin. Second-line options consist of unfractionated heparin (UFH), fondaparinux, and warfarin. For most patients undergoing knee or hip arthroplasty, the initial agents recommended for the early perioperative period are LMWHs (enoxaparin or dalteparin) or direct oral anticoagulants (rivaroxaban or apixaban). In the case of hip fracture surgery, LMWH is recommended as the preferred agent for the entire duration of prophylaxis. However, emerging factor XI(a) inhibitors, as revealed by a recent meta-analysis, have shown a substantial decrease in the occurrence of VTE and bleeding events among patients undergoing major orthopedic surgery. This discovery poses a challenge to the existing paradigm of anticoagulant therapy in this specific patient population and indicates that factor XI(a) inhibitors hold great promise as a potential strategy to be taken into serious consideration.

Complications and outcomes of pregnancy in patients with antiphospholipid antibodies during various treatment methods

Introduction. Antiphospholipid antibodies (APAs) exert multifaceted effects on the course of pregnancy by disrupting microcirculation, affecting the hemostasis, as well as damaging the endothelial membranes, leading to early reproductive loss and development of placenta-associated complications depending on the affected gestation stage. Planning and management of pregnancy in women in the absence of criteria for complete antiphospholipid syndrome (APS) currently remains unresolved issue. The absence of generally accepted treatment standards for this category of patients and inability to substantiate the diagnosis according to the APS classification criteria complicate selection of therapeutic tactics.Aim: to conduct a comparative analysis of therapy-based complications and outcomes of pregnancy in APA carriers.Materials and Methods. During the period 2019–2021 a prospective study of 150 patients who entered pregnancy with aggravated obstetric and gynecological history, serum APA level was examined. Considering the risks of developing obstetric and thrombotic complications, all patients were prescribed prophylactic doses of low molecular weight heparins (LMWHs) and low doses of acetylsalicylic acid (ASA). The patients were divided into 3 groups using a random number generator. Group 1 (n = 50), in addition to the prescribed LMWH (enoxaparin sodium 40 mg 1 time per day) and ASA (150 mg 1 time per day), also underwent plasmapheresis (PF) 4 sessions per 1 course in 6–8, 12–14 and 22–24 weeks of pregnancy; group 2 (n = 50) received courses of intravenous immunoglobulins (IVIG) at a course dose of 300 ml (15 g) simultaneously; group 3 (n = 50) received no additional therapies. Rate of pregnancy complications was comparatively assessed – development of fetal growth retardation (FGR), low birth weight fetus, gestational arterial hypertension (AH), moderate and severe preeclampsia (PE), anemia and delivery outcomes.Results. It was found that in group 3 there was a higher incidence of gestational hypertension (p2,3 &lt; 0.0001), moderate PE (p 1,3 =0.071; p 2,3 = 0.0019), low weight fetus for gestational age (p2,3 = 0.0002) and FGR (p2,3 = 0.003). In group 1, compared with group 2, there were more often observed small weight for gestational age fetus (p1,2 = 0.018) and FGR (p1,2 = 0.024), gestational hypertension (p1,2 = 0.0008), anemia (p1,2 &lt; 0.0001) and latent iron deficiency (p1,2 &lt; 0.0001). Also, groups 2 and 3 vs. group 1 were more likely to have intrahepatic cholestasis during pregnancy (p1,2 = 0.013; p1,3 = 0.003).Conclusion. In the group of patients receiving complex therapy consisting of LMWHs prophylactic doses, low ASA doses and IVIG courses, the risks of developing placenta-associated complications and iron deficiency were reduced compared to other groups indicating about a higher efficiency of this therapy regimen. However, the development of intrahepatic cholestasis during pregnancy was less common in the group of patients receiving PF courses, in contrast to using IVIG courses, which can be accounted for by additional effect of efferent therapeutic methods and should be taken into account in a differentiated approach for management of patients with liver and gallbladder pathology.

OKL-1111, A modified cyclodextrin as a potential universal reversal agent for anticoagulants

BackgroundAntithrombotic therapy is inevitably associated with a risk for bleeding and these bleeding complications can be life-threatening. Recently, specific reversal agents were developed for the direct factor Xa and thrombin inhibitors (DOACs). However, next to the fact that these agents are relatively expensive, the use of selective reversal agents complicates treatment of bleeding patients in practice. In a series of screening experiments, we discovered a class of cyclodextrins with procoagulant properties. In this study we characterize a lead compound, OKL-1111, and demonstrate its potential use as a universal reversal agent. ObjectivesTo assess the anticoagulant reversal properties of OKL-1111, in vitro and in vivo. MethodsThe effect of OKL-1111 on coagulation in the absence and presence of DOACs was investigated in a thrombin generation assay. Its reversal effect on a variety of anticoagulants in vivo was investigated in a rat tail cut bleeding model. A possible prothrombotic action of OKL-1111 was assessed in a Wessler model in rabbits. ResultsOKL-1111 concentration-dependently reversed the in vitro anticoagulant effects of dabigatran, rivaroxaban, apixaban and edoxaban in the thrombin generation assay. Also in the absence of a DOAC, OKL-1111 concentration-dependently accelerated coagulation in this assay, but did not initiate coagulation. The reversal effect was also seen for all DOACs in the rat tail cut bleeding model. In addition, when tested with other anticoagulants, OKL-1111 also reversed the anticoagulant effect of the vitamin K antagonist warfarin, the low molecular weight heparin enoxaparin, the pentasaccharide fondaparinux and the platelet inhibitor clopidogrel in vivo. OKL-1111 did not have prothrombotic effects in the Wessler model. ConclusionOKL-1111 is a procoagulant cyclodextrin with a currently unknown working mechanism that has potential to become a universal reversal agent for anticoagulants and platelet inhibitors.

COMPARISON OF SAFETY AND EFFICACY OF RIVAROXABAN AND ENOXAPARIN FOR TREATMENT OF CANCER ASSOCIATED VENOUS THROMBOEMBOLISM

The retrospective study was conducted in Nishtar Medical Hospital from January 2022 to January 2023 to compare the safety and efficacy of Rivaroxaban with low molecular weight heparin (LMWH) such as enoxaparin for the treatment of cancer-associated venous thromboembolism (VTE). A total of 250 patients were included in the study. The participants were divided into a control group (who received LMWH (enoxaparin)) and a study group (who received Rivaroxaban). The primary outcome was the occurrence of symptomatic VTE and major bleeding events during the follow-up period. After 3 months, VTE recurred in 1 (1.6%) patient in the rivaroxaban group and 6 (3.1%) patients in the enoxaparin group. After 3 months, Rivaroxaban had 4 (6.6%), and the enoxaparin group had 5 (2.6%) major bleeding events. During the 3 to 12-month period, there was no significant difference regarding treatment outcomes in groups. Based on the results, we can conclude from this study that Rivaroxaban offers effective therapy for cancer-associated VTE, but its bleeding complications are higher than LMWH.

Prognostic Significance of the Coagulation and Complement Systems in Critical COVID-19 Infection.

Infection with the SARS-CoV-2 virus (COVID-19 disease) can cause a wide range of clinical situations - from an asymptomatic state to fatal outcomes. In cases of serious clinical manifestations, the underlying mechanisms involve a number of immune cells and stromal cells as well as their products such as pro-inflammatory interleukin-6 and tumour necrosis factor-alpha that ultimately cause the cytokine storm. The situation of overproduction of pro-inflammatory cytokines is somewhat similar to, though in a mild form, health conditions in obesity and related metabolic disorders like type-2 diabetes, which are also considered important risk factors for severe illness in COVID-19. Interestingly, neutrophils perhaps play a significant role in this pathogenesis. On the other hand, it is thought that COVID-19-related critical illness is associated with pathological hyperactivity of the complement system and coagulopathy. Although the precise molecular interactions between the complement and coagulation systems are not clear, we observe an intimate cross-talk between these two systems in critically ill COVID-19 patients. It is believed that both of these biological systems are connected with the cytokine storm in severe COVID-19 disease and actively participate in this vicious cycle. In order to hinder the pathological progression of COVID-19, a number of anticoagulation agents and complement inhibitors have been used with varying success. Among these drugs, low molecular weight heparin enoxaparin, factor Xa inhibitor apixaban, and complement C5 inhibitor eculizumab have been commonly used in patients with COVID-19. Our overall experience might help us in the future to tackle any such conditions.

Thrombin Generation Is Differentially Affected By Anticoagulants in Patients with Acute Lymphoblastic Leukemia - an Ex-Vivo Study

Background: Venous thromboembolism (VTE) is a frequent complication in patients with acute lymphoblastic leukemia (ALL). Low molecular weight heparin (LMWH) reduces the risk of VTE in ALL, but is not well tolerated in children. VTE rates remain unacceptably high in adults despite LMWH prophylaxis. Thus, novel strategies for VTE prevention are warranted. In the primary analysis of the PREVAPIX-ALL trial there was no statistically significant reduction in VTE among children treated with the oral factor Xa inhibitor, apixaban, compared to no anticoagulation (AC). Comparative data on activity of different anticoagulants are needed to guide planning of VTE prophylaxis trials. Aims: To characterize and compare the ex-vivo effect of LMWH (enoxaparin), oral direct factor Xa inhibitors (apixaban, rivaroxaban) and oral direct thrombin inhibitor (dabigatran etexilate) in ALL patients' samples using thrombin generation (TG). Methods: A prospective observational cohort study of 46 children with newly-diagnosed ALL, treated with the L-asparaginase (ASP)-based BFM protocol, at a tertiary medical center. Patients on therapeutic-dose AC at baseline were excluded. Blood samples were drawn before ASP treatment (ALL-Day0) and 7 days after (ALL-Day7). Normal pooled plasma (NP) was collected from healthy adult volunteers. Samples were spiked ex-vivo with enoxaparin [0.2 U/mL], apixaban [39 ng/mL], rivaroxaban [39 ng/mL] and dabigatran [150 ng/mL] or vehicle (i.e., control). AC concentrations chosen based on 50% peak reduction (for Xa inhibitors) or 200% LT prolongation (for dabigatran) in NP. Subsequently, TG was performed initiated using 5 pM tissue factor in the presence of 4 µM phospholipids using Calibrated Automated Thrombogram method in these samples. Results are expressed as peak height (PH) and lag time (LT) and relative reduction or prolongation (% difference in PH or LT, respectively) in plasma samples spiked with anticoagulants compared to control. Reduction in PH reflects enoxaparin, apixaban and rivaroxaban activity, while LT prolongation indicates dabigatran activity. This report focuses on measures reflecting the activity of each drug. Descriptive statistics were used to show the median [interquartile range (IQR)] for continuous variables and percentages for categorical data. T-Test / Mann-Whitney U test and paired T-test / Wilcoxon test used to compare between paired and non-paired samples, respectively. Results: Selected sample characteristics are as follows: median age, 7.75 years [IQR 3.73-11.93]; 19 (41%) females; median BMI, 16.8 [IQR 15.5-19.9]; B-cell precursor immunophenotype in 33 (71.7%) and T-cell in 13 (28.3%); prior VTE in 1 (2%). Median PH [IQR] in control samples (without AC) was 256.6 [252.6-265.3] nmol/l, 396.0 [347.2-464.7] nmol/l and 354.4 [307.1-407.4] nmol/l in NP, ALL-Day0 and ALL-Day7 respectively. Median LT [IQR] in control samples was 2.7 [2.5-2.83] nmol/l, 1.8 [1.7-2.3] nmol/l and 1.7 [1.6-2] nmol/l in NP, ALL-Day0 and ALL-Day7 respectively. Median % differences in PH and LT between samples spiked with different anticoagulants and controls are shown in Figure 1A and Figure 1B, respectively. Enoxaparin, apixaban and rivaroxaban reduced PH in NP, ALL-Day0 and ALL-Day7 samples (p<0.0005). There was less reduction in PH with enoxaparin, apixaban and rivaroxaban in ALL-Day0 samples than in NP (p=0.029, p<0.0005, p<0.0005 respectively), suggesting reduced anticoagulant activity in ALL patients compared to subjects without ALL. LT was prolonged with dabigatran in NP, ALL-Day0 and ALL-Day7 samples (p<0.05). Dabigatran resulted in a similar LT prolongation in ALL-Day0 and NP (p=0.677), suggesting a preserved AC effect in ALL. There was less LT prolongation in ALL-Day7 (134% [123-175%] than in ALL-Day0 (180% [134-238]; p=0.031). This reflects an ongoing dabigatran effect after ASP, albeit to a lesser degree. Conclusions: Our ex-vivo results suggest limited anticoagulant activity of enoxaparin and lack of anticoagulant activity of apixaban and rivaroxaban (both factor Xa inhibitors) in preventing VTE in ALL, in line with prior clinical data. In contrast, dabigatran etexilate, an oral direct thrombin inhibitor not previously tested in ALL, exhibited preserved anticoagulant activity in ALL patients, even after exposure to ASP. This may suggest that dabigatran should be investigated in clinical studies for the unmet need of VTE prophylaxis in ALL. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Risk of Venous Thromboembolism or Hemorrhage Among Individuals with Chronic Kidney Disease Taking a Direct Oral Anticoagulant Compared to Low-Molecular-Weight Heparin after a Hip or Knee Arthroplasty

Background: Individuals with chronic kidney disease (CKD) are at exceptionally high risk of both thrombosis and bleeding events. Limited comparative effectiveness evidence exists regarding the optimal choice of thromboprophylaxis in those with CKD. We set out to compare the safety and effectiveness of direct oral anticoagulants (DOACs) versus low-molecular-weight heparin (LMWH) among older individuals with CKD following hip or knee arthroplasty. Objective: To assess the 90-day risk of a venous thromboembolism (VTE) or hemorrhage with DOAC use compared to LWMH after hip or knee arthroplasty among older individuals with CKD. Methods: A population-based, retrospective cohort study was conducted among adults of age ≥ 66 with CKD undergoing hip or knee arthroplasty who had filled an outpatient DOAC prescription (apixaban, rivaroxaban, dabigatran, edoxaban) after surgery compared to LMWH (enoxaparin, dalteparin, tinzaparin) between January 1, 2010 and December 31, 2020 in Ontario, Canada. CKD was defined by at least one estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 within 2 years or the presence of chronic dialysis within 5 years. Index was the date of first filling of the outpatient anticoagulant prescription after hip or knee arthroplasty. The primary effectiveness outcome was VTE and the primary safety outcome was any hemorrhage identified by validated algorithms using relevant diagnosis and billing codes. Patients were followed until 90 days after index, end of Ontario insurance, death, or the end of follow-up period on March 31, 2021. Overlap weighted cause-specific Cox proportional hazard models were used to examine the association of the 90-day risk of a VTE and/or a hemorrhage event accounting death as a competing risk. In additional analyses, we examined a more stringent VTE defining algorithm (diagnostic codes plus procedure codes within 7 days), different eGFR cut-offs, limiting to the most commonly used DOAC and LWMH (rivaroxaban vs. enoxaparin), and a shorter (30-day) follow up period. Results: A total of 27,645 patients were prescribed DOAC or LMWH after arthroplasty (66.7% female, mean age 76, DOAC: 22,943, LMWH: 4,702, mean eGFR 51.6 mL/min, 17.7% with eGFR < 45 mL/min). DOAC users had higher eGFRs, less comorbidity, had surgeries in more recent years, were more likely to be treated in community hospitals, and with shorter time from surgery to index compared to LMWH users (Table 1). After accounting for multiple covariates, the use of DOAC, compared to LMWH, was associated with less VTE events (DOAC: 341/22,943 [1.5%] vs LMWH: 97/4,702 [2.1%], weighted hazard ratio [wHR] 0.75, 95% confidence interval [CI] 0.59-0.94) and more hemorrhage events (DOAC: 290/22,943 [1.3%] vs LMWH: 45/4,702 [1.0%], wHR 1.44, 95% CI 1.04-1.99) (Table 2)]. The findings were consistent in all additional analyses (Table 2). Conclusions: Among older adults with CKD, DOAC use was associated with lower VTE and higher hemorrhage risk compared to LMWH following knee or hip arthroplasty. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Enoxaparin versus Unfractionated Heparin for the Perioperative Anticoagulant Therapy in Patients with Mechanical Prosthetic Heart Valve Undergoing Non-Cardiac Surgery.

Background and Objectives: Immediate postoperative anticoagulation regimens in patients with mechanical prosthetic valves undergoing non-cardiac surgery are clear only for unfractionated heparin (UH), whereas the few low-molecular-weight heparin (LMWH) trials available to date concern the use of Enoxaparin in general/orthopedic surgery. We performed a single-center real-world data study comparing the efficacy and safety of LMWH—Enoxaparin (E)— and UH during the perioperative period in non-cardiac surgical procedures in patients with mechanical prosthetic valve replacement in the mitral, aortic, or tricuspid positions. Materials and Methods: We enrolled 380 patients, who received E or UH together with oral anticoagulation with antivitamin K (acenocoumarol) until they achieved an optimal International Normalized Ratio (INR). Objective assessment of E efficacy included the following: normal value for all the parameters of ultrasound prosthetic functioning, no early thrombosis of the prosthesis, and rapid achievement of target INR with a decreased period of subcutaneous anticoagulation. Subjective assessment included the following: clinical improvement with decreased immobilization and in-hospital stay, fewer gluteal ulcerations, and fewer postoperative depression and anxiety episodes. Results: Comparing with UH, anticoagulation with E was more effective (p < 0.0001 and p = 0.02). The probability of death was smaller in the E group compared with the UH group. No major hemorrhagic event was reported. Mild bleeding episodes and thrombocytopenia were more common in the UH group. Patient’s compliance and quality of life were better with E due to shortened hospitalization, decreased need for testing of coagulation (every 6 h for UH), better dosing (SC every 12 h for E versus continuous infusion for UH), shortened immobilization during the immediate postoperative period with subsequent improvement in the psychological status, as well as due to lack of significant side effects. Conclusions: Taking into consideration the improved efficiency and safety, as well as all the supplementary advantages, such as no need for anticoagulation monitoring, the ease of administration, and reduced duration of hospitalization, E should be seen as an attractive alternative for anticoagulation which deserves further investigation.

Prevention of Deep Vein Thrombosis by Panax Notoginseng Saponins Combined with Low-Molecular-Weight Heparin in Surgical Patients.

To evaluate the efficacy of deep vein thrombosis (DVT) prevention among real-world surgical inpatients who received panax notoginseng saponins (PNS) combined with low-molecular-weight heparin (LMWH). A prospective cohort study was conducted among surgical patients between January 2016 and November 2018 in Xuanwu Hospital, Capital Medical University, Beijing, China. Participants received LMWH alone or PNS combined with LMWH for preventing DVT. The primary outcome was incidence of lower extremity DVT, which was screened once a week. Participants in the LMWH group were given LMWH (enoxaparin) via hypodermic injection, 4000-8000 AxalU once daily. Participants in the exposure group received PNS (Xuesaitong oral tablets, 100 mg, 3 times daily) combined with LMWH given the same as LMWH group. Of the 325 patients screened for the study, 281 participants were included in the final analysis. The cohort was divided into PNS + LMWH group and LMWH group with 134 and 147 participants, respectively. There was a significant difference of DVT incidence between two groups (P=0.01), with 21 (15.7%) incident DVT in the PNS + LMWH group, and 41 (27.9%) incident DVT in the LMWH group. Compared with participants without DVT, the participants diagnosed with DVT were older and had higher D-dimer level. The multivariate logistic regression model showed a significant lower risk of incident DVT among participants in the PNS + LMWH group compared with the LMWH group (odds ratio 0.46, 95% confidence interval, 0.25-0.86). There were no significant differences in thromboelaslography values (including R, K, Angle, and MA) and differences in severe bleeding between two groups. No symptomatic pulmonary embolism occurred during the study. Combined application of PNS and LMWH can effectively reduce the incidence of DVT among surgical inpatients compared with LMWH monotherapy, without increased risk of bleeding.

A Factor XIa Inhibitor Engineered from Banded Krait Venom Toxin: Efficacy and Safety in Rodent Models of Arterial and Venous Thrombosis.

Activated factor XI (FXIa) is an important antithrombotic drug target. Clinical and pre-clinical data have demonstrated that its inhibition attenuates thrombosis with minimal risk of excessive bleeding. We isolated Fasxiator from the venom of banded krait Bungarus fasciatus and subsequently engineered FasxiatorN17R,L19E, with improved affinity (Ki = 0.9 nM) and selectivity towards FXIa. Here, we assess the in vivo efficacy and bleeding risk of rFasxiatorN17R, L19E in pre-clinical animal models. Rats injected intravenously (i.v.) with bolus rFasxiatorN17R, L19E showed the specific in vivo attenuation of the intrinsic coagulation pathway, lasting for at least 60 min. We performed the in vivo dose-ranging experiments for rFasxiatorN17R, L19E as follows: FeCl3-induced carotid artery occlusion in rats (arterial thrombosis); inferior vena cava ligation in mice (venous thrombosis); tail bleeding time in both rats and mice (bleeding risk). Head-to-head comparisons were made using therapeutic dosages of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) for arterial and venous thrombosis, respectively. In the arterial thrombosis model, 2 mg/kg i.v. rFasxiatorN17R,L19E achieved a similar antithrombotic efficacy to that of UFH, with >3-fold lower bleeding time. In the venous thrombosis model, the 10 mg/kg subcutaneous (s.c.) injection of rFasxiatorN17R,L19E achieved similar efficacy and bleeding levels to those of LMWH enoxaparin. Overall, rFasxiatorN17R,L19E represents a promising molecule for the development of FXIa-targeting anticoagulants.

Parenteral anticoagulants in the treatment of acute coronary syndrome: what modern clinical guidelines say

Parenteral administration of high (therapeutic) doses of anticoagulants is a mandatory component of the initial treatment of acute coronary syndrome (ACS) unless contraindicated. In ACS, intravenous administration of unfractionated heparin, the use of low molecular weight heparin enoxaparin, selective antagonist of activated X clotting factor fondaparinux sodium and direct thrombin antagonist bivalirudin are possible. The review presents current approaches to the choice of drugs and the specifics of parenteral anticoagulant use depending on ACS variant (with or without persistent ST-segment elevations on ECG), approaches to myocardial revascularization, previous use of oral anticoagulants, renal function, risk of major bleeding, presented in current versions of European Society of Cardiology and Russian Society of Cardiology guidelines, approved by the Russian Ministry of Health. It is shown that, according to the results of randomized controlled trials and expert opinion, for most ACS treatment scenarios (streptokinase thrombolytic therapy or no reperfusion therapy in ACS with persistent ST elevation on ECG, ACS without persistent ST elevation) the optimal approach is parenteral administration of sodium fondaparinux. Exceptions include primary percutaneous coronary intervention and very early invasive treatment of ACS without persistent ST-segment elevation, but initial treatment with sodium fondaparinux does not prevent these approaches. Additional advantages of sodium fondaparinux are the absence of the need to monitor the coagulation system, a fixed dose, as well as the possibility of use in patients with significant thrombocytopenia. If short-term use of parenteral anticoagulant is expected (in early invasive treatment of ACS), there are contraindications or limitations to the use of sodium fondaparinux and sodium enoxaparin, the means of choice for most cases is intravenous administration of unfractionated heparin.

Pharmacokinetic, Hemostatic, and Anticancer Properties of a Low-Anticoagulant Bovine Heparin.

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

Pharmacokinetic, Hemostatic, and Anticancer Properties of a Low-Anticoagulant Bovine Heparin

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

Anti-Xa based dosing of enoxaparin in hematopoietic stem cell transplant and adoptive cell therapy patients: A single center experience

Patients undergoing hematopoietic stem cell transplantation (HSCT) and adoptive cell therapies (ACT) are at an increased risk of venous thromboembolism (VTE) [1,2]. A concurrently elevated risk of bleeding in the setting of thrombocytopenia, graft versus host disease (in recipients of allogeneic HSCT) and coagulopathy complicates therapeutic anticoagulation (TAC) in this patient population [3,4]. TAC, when administered to HSCT and ACT patients in the peri-transplant setting at our center, is achieved with the low-molecular weight heparin (LMWH) enoxaparin.