Tinzaparin and other low-molecular-weight heparins: what is the evidence for differential dependence on renal clearance?

Smaller nadroparin dose reductions required for patients with renal impairment: A multicenter cohort study

BACKGROUND

Guidelines advise 50 % and 25 % dose reduction of the therapeutic nadroparin dose (86 IU/kg) in patients with eGFR 15-29 and 30-60 ml/min respectively. For monitoring, peak anti-Xa levels are suggested. Data lack whether this results in therapeutic anti-Xa levels or in anti-Xa levels that are comparable to those of patients without renal impairment.

AIMS

To determine dose ranges in patients with renal impairment that result in therapeutic anti-Xa levels and to determine the percentage of the 86 IU/kg dose that results in anti-Xa levels normally occurring in patients without renal impairment.

METHODS

A retrospective cohort study was conducted in five hospitals. Patients ≥18 years of age, with an eGFR ≥ 15 ml/min were included. The first correctly sampled peak (i.e. 3-5 h after ≥ third administration, regardless of dose per patient) was included. Simulated prediction models were developed using multiple linear regression.

RESULTS

770 patients were included. eGFR and hospital affected the association between dose and anti-Xa level. The doses for peak anti-Xa levels of 0.75 IU/ml differed substantially between hospitals and ranged from 55 to 91, 65-359 and 68-168 IU/kg in eGFR 15-29, 30-60 and > 60 ml/min/1.73m2, respectively. In eGFR 15-29 and 30-60 ml/min/1.73m2, doses of 75 % and 91 % of 86 IU/kg respectively, were needed for anti-Xa levels normally occurring in patients with eGFR > 60 ml/min.

CONCLUSION

We advise against anti-Xa based dose-adjustments as long as anti-Xa assays between laboratories are not harmonized and an anti-Xa target range is not validated. A better approach might be to target levels similar to eGFR > 60 ml/min/1.73m2, which are achieved by smaller dose reductions.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Efficacy and safety of anticoagulant for treatment and prophylaxis of VTE patients with renal insufficiency: a systemic review and meta-analysis

Patients with venous thromboembolism (VTE) comorbid renal insufficiency (RI) are at higher risk of bleeding and thrombosis. Recommendations in guidelines on anticoagulation therapy for those patients remain ambiguous. The goal of this study is to compare the efficacy and safety between different anticoagulant regimens in VTE patients comorbid RI at different stages of treatment and prophylaxis. We performed English-language searches of Pubmed, EMBASE, and Web of Science (inception to Nov 2022). RCTs evaluated anticoagulants for VTE treatment at the acute phase, extension phase, and prophylaxis in patients with RI and reported efficacy and safety outcomes were selected. The methodological quality of the studies was assessed at the outcome level using the risk-of-bias assessment tool developed by the Cochrane Bias Methods Group. A meta-analysis of twenty-five RCTs was conducted, comprising data from twenty-three articles, encompassing a total of 9,680 participants with RI. In the acute phase, the risk of bleeding was increased with novel oral anticoagulants (NOACs) compared to LMWH (RR 1.29, 95% CI 1.04-1.60). For the prophylaxis of VTE, NOACs were associated with an elevated risk of bleeding compared with placebo (RR 1.31, 95%CI 1.02-1.68). In comparison to non-RI patients, both NOACs and vitamin K antagonists (VKA) could increase the risk of bleeding among RI patients (RR 1.45, 95%CI 1.14-1.84 and RR 1.53, 95%CI 1.25-1.88, respectively) during acute phase, while NOACs may increase the incidence of VTE in RI population (RR 1.74, 95%CI 1.29-2.34). RI patients who are under routine anticoagulation have a significantly higher risk of adverse outcomes. LMWH is the most effective and safe option for VTE treatment or prophylaxis in patients with RI.

Anti-coagulant Treatment of Cancer-Associated Thrombosis in Frail Patients: Impact of Frailties on the Management of Drug-Drug Interactions

Low molecular weight heparins (LMWH) and anti-Xa direct oral anti-coagulants (DOACs) are recommended for the long-term treatment of cancer-associated thrombosis (CAT) based on well-documented randomised controlled trials. Anti-Xa DOACs are viewed as a first choice for the treatment of patients with CAT. A large number of drug-drug interactions have been reported between DOACs and chemotherapy drugs, modifying circulating levels of DOAC leading to fears of increased bleeding risks or thrombotic recurrence. Progresses in anti-neoplastic therapies have improved the prognosis and the survival, thus increasing the prevalence of frail patients with cancer. However, since frailties tend to be excluded from large trials due to multiple co-morbidities, current guidelines are not fully applicable to this population. The management of these frail patients with CAT is particularly complex and requires a risk assessment on a case-by-case basis with specific focus on cancer, patient-related risk factors and drug-drug interactions. In this brief review we have identified age, co-morbidities and co-medications as key factors of frailty that require careful attention and we have developed a therapeutic decision algorithm to help clinicians optimising the use of anti-coagulants in patients with cancer with CAT, especially in case of anti-Xa DOACs concomitant medications. With the evaluation of the bleeding risk according to the type of cancer, and anticipating drug-drug interactions intensity, taking into account patient frailties allows the optimisation of the anti-coagulant choice. A systematic collaboration between oncologists, vascular pathology specialists and pharmacists is warranted to ensure an optimal patient management. Clinical studies are needed to determine the real impact of these interactions.

The Role of Injectables in the Treatment and Prevention of Cancer-Associated Thrombosis

Cancer-associated thrombosis (CAT) is a leading cause of death among patients with cancer. CAT can manifest itself as venous thromboembolism (VTE), in the form of deep vein thrombosis or pulmonary embolism, or arterial thromboembolism. The pathophysiology of CAT is complex and depends on cancer-, patient-, treatment- and biomarkers-related factors. Treatment of VTE in patients with cancer is complex and includes three major classes of anticoagulant agents: heparin and its derivatives, e.g., low molecular weight heparins, direct oral anticoagulants (DOACs), and vitamin K inhibitors. Given the tremendous heterogeneity of clinical situations in patients with cancer and the challenges of CAT, there is no single universal treatment option for patients suffering from or at risk of CAT. Initial studies suggested that patients seemed to prefer an anticoagulant that would not interfere with their cancer treatment, suggesting the primacy of cancer over VTE, and favoring efficacy and safety over convenience of route of administration. Recent studies show that when the efficacy and safety aspects are similar, patients prefer the oral route of administration. Despite this, injectables are a valid option for many patients with cancer.

Single-Bolus Tinzaparin Anticoagulation in Extended Hemodialysis Session: A Feasibility Study

Key Points

A single bolus of tinzaparin is effective for 8-hour hemodialysis session. Eight-hour simulation sessions with anti-Xa monitoring are useful to adjust tinzaparin dose.

Background

Few studies have assessed the use of low-molecular weight heparins for anticoagulation during extended hemodialysis (HD) sessions. This study aimed to evaluate the efficacy of a single bolus of tinzaparin for anticoagulation of the extracorporeal circuit and dialyzer in 8-hour HD sessions.

Methods

This single-center study included all patients who underwent a single 8-hour simulation session as part of their nocturnal home HD training between 2009 and 2020. Tinzaparin was delivered as a single-bolus injection at time 0 with dosing on the basis of doubling of standard 4-hour session dose. Tinzaparin efficacy was examined using visual observations (score 1–4) of the dialyzer and venous bubble trap at the end of dialysis and using anti-Xa measured at 15 and 30 minutes and 1, 2, 4, 6, and 8 hours after HD start.

Results

Forty-seven patients were included. The mean tinzaparin dose was 107±20 IU/kg. Anti-Xa levels peaked at 15 minutes with 1.3±0.4 IU/ml and progressively declined reaching 0.9±0.3 IU/ml at 1 hour, 0.4±0.21 IU/ml at 4 hours, and 0.15±0.15 IU/ml at 8 hours. After the 8-hour session, none of the patients had severe clotting of their dialyzer or venous chamber. Moderate blood clotting was observed in the dialyzer of 6 patients (20%) and in the venous chamber of 22 patients (61%). On the basis of the simulation results, tinzaparin dose was increased in 27 patients (58%) with a mean home-discharge dose of 123±28 IU/kg.

Conclusions

This study shows that anti-Xa levels stabilized rapidly after administration of tinzaparin for 8-hour HD. Administration of a single-bolus tinzaparin at the start of an 8-hour dialysis session seemed effective, although dose adjustment may be required.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Weight-adjusted dosing of tinzaparin for thromboprophylaxis in obese medical patients

Background

The optimal dose of tinzaparin for prophylaxis in obese medical patients is not well defined.

Objectives

To evaluate the anti-Xa activity in obese medical patients on tinzaparin prophylaxis adjusted for actual bodyweight.

Methods

Patients with a body mass index of ≥30 kg/m² treated with 50 IU/kg tinzaparin once daily were prospectively included. Anti-Xa and anti-IIa activity; von Willebrand factor antigen and von Willebrand activity; factor VIII activity; D-dimer, prothrombin fragments; and thrombin generation were measured 4 hours after subcutaneous injection between days 1 and 14 after the initiation of tinzaparin prophylaxis.

Results

We included 121 plasma samples from 66 patients (48.5% women), with a median weight of 125 kg (range, 82-300 kg) and a median body mass index of 41.9 kg/m² (range, 30.1-88.6 kg/m²). The target anti-Xa activity of 0.2 to 0.4 IU/mL was achieved in 80 plasma samples (66.1%); 39 samples (32.2%) were below and 2 samples (1.7%) above the target range. The median anti-Xa activity was 0.25 IU/mL (IQR, 0.19-0.31 IU/mL), 0.23 IU/mL (IQR, 0.17-0.28 IU/mL), and 0.21 IU/mL (IQR, 0.17-0.25 IU/mL) on days 1 to 3, days 4 to 6, and days 7 to 14, respectively. The anti-Xa activity did not differ among the weight groups (P = .19). Injection into the upper arm compared to the abdomen resulted in a lower endogenous thrombin potential, a lower peak thrombin, and a trend to a higher anti-Xa activity.

Conclusion

Dosing of tinzaparin adjusted for actual bodyweight in obese patients achieved anti-Xa activity in the target range for most patients, without accumulation or overdosing. In addition, there is a significant difference in thrombin generation depending on the injection site.

Tinzaparin for venous thromboembolism in patients with renal impairment: a single-centre, prospective pilot study

BACKGROUND

Low molecular weight heparins (LMWH) are used extensively for prophylaxis and treatment of venous thromboembolism (VTE), bridging therapy for warfarin and standard of care in cancer-associated VTE (CA-VTE). Tinzaparin has the highest molecular weight of all LMWH and relies least on renal clearance to Cockcroft-Gault creatinine clearance (CrCl) of 20 mL/min. Previous pharmacological studies have demonstrated safety and effectiveness in elderly patients. Prospective clinical trials have confirmed these findings to CrCl 20 mL/min and in CA-VTE. We describe the pilot program developed at Concord Repatriation General Hospital for tinzaparin.

AIMS

We aim to confirm the deliverability of tinzaparin in patients with renal insufficiency.

METHODS

Twenty patients were established on tinzaparin as therapeutic anticoagulation with CrCl or CKD-EPI estimated glomerular filtration rate (eGFR) 20-50 mL/min with an indication for anticoagulation. Tinzaparin was given as a subcutaneous injection at 175 units/kg as a single daily dose, rounded to the nearest vial size. Tinzaparin anti-Xa levels were tested at Days 2, 7 and 14 (±1 day) and transition to oral anticoagulants were allowed at clinician discretion.

RESULTS

No accumulation of tinzaparin was seen into Day 14. Two patients required dose-adjustment, five patients had bleeding complications (two major, three minor) and four patients died during follow-up, all attributable to patients' comorbidities. CrCl and body surface area-standardised CrCl were significantly correlated with tinzaparin anti-Xa level only on Day 2, and this effect was lost when patients with CrCl >50 mL/min were excluded. Data from our cohort confirm the deliverability of therapeutic tinzaparin in patients with CrCl or CKD-EPI eGFR 20-50 mL/min. Bleeding and death outcomes were also comparable to other trials using tinzaparin in CA-VTE.

CONCLUSION

For patients with renal insufficiency, tinzaparin represents an attractive alternative anticoagulant with once-daily administration in a range of potential indications.

Tinzaparin—a review of its molecular profile, pharmacology, special properties, and clinical uses

Purpose

Low molecular weight heparins (LMWHs) are a group of heterogenous moieties, long used in the prevention and treatment of thrombosis. They derive from heparin and since they are prepared by different methods of depolymerization, they differ in pharmacokinetic properties and anticoagulant profiles, and thus are not clinically interchangeable.

Methods

In this review we provide an overview of tinzaparin's main characteristics and uses.

Results

Tinzaparin which is produced by the enzymatic depolymerization of unfractionated heparin (UFH) can be used for the treatment and prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE); it has been also used in special populations such as elders, obese, pregnant women, and patients with renal impairment and/or cancer with favorable outcomes in both safety and efficacy, with a once daily dose regimen. Furthermore, LMWHs are extensively used in clinical practice for both thromboprophylaxis and thrombosis treatment of COVID-19 patients.

Conclusion

Tinzaparin features support the hypothesis for having a role in immunothrombosis treatment (i.e. in the context of cancer ,COVID-19), interfering not only with coagulation cascade but also exhibiting anti-inflammatory potency.

Therapeutically dosed low molecular weight heparins in renal impairment: a nationwide survey

PURPOSE

International guidelines vary in their recommendations whether or not to reduce the therapeutic dose of low molecular weight heparins (LMWHs) in renal impairment. The use of anti-Xa monitoring as a basis of dose adjustments is also a matter of debate. As this may lead to variations in treatment policies, we aimed to study the treatment policies of therapeutically dosed LMWHs in renal impairment in Dutch hospitals.

METHODS

An 11-item survey was distributed between June 2020 and March 2021 to hospital pharmacists, representing Dutch hospital organisations. Primary outcomes were the dosing regimens of therapeutically dosed LMWHs in renally impaired patients. Secondary outcomes were the proportion of hospitals that used anti-Xa monitoring and the anti-Xa target range used.

RESULTS

There was a response from 56 of 69 (81%) Dutch hospital organisations where in each case a hospital pharmacist completed the survey. In these hospitals, 77 LMWH regimens were in use. In 76 of 77 (99%) regimens, a regular dose reduction was used at the start of treatment. Fifty-five of these hospitals used a dose reduction if estimated glomerular filtration rate (eGFR) < 50 ml/min and 17 used a dose reduction if eGFR < 30 ml/min. Anti-Xa levels were not routinely monitored in 40% of regimens, while 22% monitored anti-Xa if eGFR < 50 ml/min, 27% if eGFR < 30 ml/min and 10% in other eGFR cutoff values. Target ranges of 1.0-2.0 IU/ml (once daily) and 0.5/0.6-1.0 IU/ml (twice daily) were used in 69% of regimens that included monitoring of anti-Xa.

CONCLUSION

Treatment policies show substantial diversity in therapeutically dosed LMWHs in renally impaired patients. The most commonly used treatment regimen was a regular dose reduction if eGFR is < 50 ml/min, without anti-Xa monitoring.

Intensive-Dose Tinzaparin in Hospitalized COVID-19 Patients: The INTERACT Study

(1) Background: It is well-established that coronavirus disease-2019 (COVID-19) is highly pro-inflammatory, leading to activation of the coagulation cascade. COVID-19-induced hypercoagulability is associated with adverse outcomes and mortality. Current guidelines recommend that hospitalized COVID-19 patients should receive pharmacological prophylaxis against venous thromboembolism (VTE). (2) INTERACT is a retrospective, phase IV, observational cohort study aiming to evaluate the overall clinical effectiveness and safety of a higher than conventionally used prophylactic dose of anticoagulation with tinzaparin administered for VTE prevention in non-critically ill COVID-19 patients with moderate disease severity. (3) Results: A total of 705 patients from 13 hospitals in Greece participated in the study (55% men, median age 62 years). Anticoagulation with tinzaparin was initiated immediately after admission. A full therapeutic dose was received by 36.3% of the participants (mean ± SD 166 ± 33 IU/Kgr/day) and the remaining patients (63.9%) received an intermediate dose (mean ± SD 114 ± 22 IU/Kgr/day). The median treatment duration was 13 days (Q1−Q3: 8−20 days). During the study (April 2020 to November 2021), 14 thrombotic events (2.0%) were diagnosed (i.e., three cases of pulmonary embolism (PE) and 11 cases of deep venous thrombosis, DVT). Four bleeding events were recorded (0.6%). In-hospital death occurred in 12 patients (1.7%). Thrombosis was associated with increasing age (median: 74.5 years, Q1−Q3: 62−79, for patients with thrombosis vs. 61.9 years, Q1−Q3: 49−72, p = 0.0149), increased D-dimer levels for all three evaluation time points (at admission: 2490, Q1−Q3: 1580−6480 vs. 700, Q1−Q3: 400−1475, p < 0.0001), one week ± two days after admission (3510, Q1−Q3: 1458−9500 vs. 619, Q1−Q3: 352−1054.5, p < 0.0001), as well as upon discharge (1618.5, Q1−Q3: 1010−2255 vs. 500, Q1−Q3: 294−918, p < 0.0001). Clinical and laboratory improvement was affirmed by decreasing D-dimer and CRP levels, increasing platelet numbers and oxygen saturation measurements, and a drop in the World Health Organization (WHO) progression scale. (4) Conclusions: The findings of our study are in favor of prophylactic anticoagulation with an intermediate to full therapeutic dose of tinzaparin among non-critically ill patients hospitalized with COVID-19.

Prophylaxis of cancer‑associated venous thromboembolism with low‑molecular‑weight heparin‑tinzaparin: Real world evidence

Thromboprophylaxis, as a preventive measure for cancer-associated thrombosis (CAT), may be beneficial for patients with active cancer and high-risk for thrombosis. The present post hoc analysis include a total of 407 patients enrolled in the Greek Management of Thrombosis study, who received thromboprophylaxis with tinzaparin. The objectives of the present analysis were: i) To obtain sufficient evidence for the administration of prophylaxis in patients with active cancer, irrespective of Khorana risk assessment model score; ii) to identify the selection criteria for both dose and duration of tinzaparin; and iii) to evaluate the efficacy and safety of tinzaparin administered for CAT prophylaxis. The main tumor types for the patients included in the present study were as follows: Lung (25.1%), pancreatic (14.3%), breast (9.1%), stomach (8.4%), colorectal (7.9%) and ovarian (7.6%). Furthermore, metastatic disease was observed in 69.5% of the patients. High thrombotic burden agents (HTBAs) were administered to 66.3% of the patients, and 17.4% received erythropoietin. A total of 43.7% of the patients exhibited a Khorana score <2. The results of the present study demonstrated that both the presence of metastatic disease and the use of HTBAs seemed to influence oncologists' decisions for the use of thromboprophylaxis in patients with active cancer, regardless of Khorana score. Tinzaparin, in dose expressed in the standard notation for heparins, i.e., anti-Xa factor international units (Anti-Xa IU), was administered at an intermediate dose (InterD; 8,000-12,000 Anti-Xa IU; once daily) to 52.4% of patients, while the remaining patients received a prophylactic dose (ProD; ≤4,500 Anti-Xa IU; once daily). The average duration of thromoprophylaxis was 5 months. Furthermore, a total of 14 (3.4%) thrombotic events and 6 (1.5%) minor bleeding events were recorded. A total of four thrombotic events were observed following an InterD treatment of tinzaparin, while 10 thrombotic events were observed following ProD treatment. The present study also demonstrated that an InterD of tinzaparin was administered more frequently to patients with a body mass index >30 kg/m², a history of smoking and a history of metastatic disease, along with administration of erythropoietin. InterD tinzaparin treatment was found to be potentially more efficacious and without safety concerns. The present study is a registered clinical trial (ClinicalTrials.gov code, NCT03292107; registration date, September 25, 2017).

Optimising the Nadroparin Dose for Thromboprophylaxis During Hemodialysis by Developing a Population Pharmacodynamic Model Using Anti-Xa Levels

INTRODUCTION

The optimal nadroparin dose in patients undergoing hemodialysis is difficult to determine in clinical practice. Anti-Xa levels ≥ 0.4 IU/mL and < 2.0 IU/mL are suggested to prevent thrombus formation within the extracorporeal circuit whilst minimizing bleeding risk. We aimed to characterize the variability in the association between dose and anti-Xa levels, identify patient and dialysis characteristics that explained this variability, and optimize nadroparin dosing based on the identified characteristics.

METHODS

Anti-Xa samples were collected in patients who received intravenous nadroparin as thromboprophylaxis during routine dialysis sessions. A population pharmacodynamic model was developed using non-linear mixed-effects modelling. The percentage of patients ≥ 0.4 IU/mL (efficacy) and < 2.0 IU/mL (safety) was simulated for different doses, patient and dialysis characteristics.

RESULTS

Patients (n = 137) were predominantly receiving standard hemodialysis (84.7% vs. hemodiafiltration 15.3%) and had a mean bodyweight of 76.3 kg (± 16.9). Lean body mass (LBM), mode of dialysis, and dialyzer partially explained between-subject variability in anti-Xa levels. Patients on hemodiafiltration and those receiving hemodialysis with a high LBM (≥ 80 kg) had a low probability (< 29%) of anti-Xa levels ≥ 0.4 IU/mL during the entire dialysis session. All patients, except hemodialysis patients with a low LBM (< 50 kg), had a high probability (> 70%) of peak anti-Xa levels < 2.0 IU/mL.

CONCLUSION

Mainly patients receiving hemodiafiltration and those receiving hemodialysis with a high LBM can benefit from a higher nadroparin dose than currently used in clinical practice, while having anti-Xa levels < 2.0 IU/mL.

Cancer-Associated Thrombosis: Not All Low-Molecular-Weight Heparins Are the Same, Focus on Tinzaparin, A Narrative Review

Cancer-associated thrombosis (CAT) is the second main cause of cancer death with high related mortality and morbidity, leading to anticancer agent delays and interruptions. The recommended therapy, low-molecular-weight heparin (LMWH), however, is burdensome for patients and costly for society, as treatment should last until cancer is no longer active, even indefinitely. Tinzaparin is a manageable, efficient, safe, and cost-effective option. Compared to the other LMWHs, advantages are single-daily dose and safety in the elderly and those with renal impairment (RI). The purpose of this review is to critically discuss recent data on its efficacy and safety in CAT.

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.

Anticoagulation in hemodialysis: A narrative review

Systemic anticoagulation in maintenance hemodialysis (HD) has historically been considered necessary to maintain the extracorporeal circuit (ECC) and preserve dialysis efficiency. Unfractionated heparin (UFH) is the most commonly used anticoagulant due to low cost and staff familiarity. Despite widespread use, there is little standardization of heparin dosing protocols in the United States. Although the complication rates with UFH are low for the general population, certain contraindications have led to exploration in alternative anticoagulants in patients with end-stage kidney disease (ESKD). Here we review the current evidence regarding heparin dosing protocols, complications associated with heparin use, and discuss alternatives to UFH including anticoagulant-free routine HD.

Haemorrhagic complications in patients with renal insufficiency during treatment or prophylaxis with dalteparin

OBJECTIVES

Low-molecular-weight heparins are widely used in clinical practice for the treatment or prophylaxis of venous thromboembolism (VTE). As these drugs are eliminated mainly by renal means, any renal function impairment may lead to higher plasma concentrations and increase the risk of bleeding. This study aims to evaluate whether in clinical practice there is an increase in the occurrence of bleeding in patients with renal insufficiency (RI) during treatment or prophylaxis with dalteparin, and to analyse the risk factors potentially influencing the appearance of such bleeding events.

METHODS

Patients were sampled from the Universitary Severo Ochoa Hospital, Leganés, Spain. This was a retrospective cohort study with a 1 year inclusion period, conducted at a Spanish university hospital with 400 beds, on patients undergoing treatment or prophylaxis for VTE with dalteparin for a minimum of 3 days. The main outcome measure was the number of patients who had bleeding events, independently of their severity, during dalteparin administration in patients with RI.

RESULTS

367 patients were included in the study. Bleeding occurred in 17.9% of patients in the group with RI and in 7.3% of patients with normal renal function (NRF). Most haemorrhages in both cohorts were grade 2 on the WHO scale (64.7% in the RI group and 69.2% in the NRF group). Logistic regression analysis allowed the presence of RI (MDRD-4 (Modification of Diet in Renal Disease) <50 mL/min) to be identified as a risk factor.

CONCLUSION

Patients with RI treated with dalteparin face a higher risk of bleeding than those with NRF, which seems to make it necessary to monitor and seek new dosage adjustments for these patients.Impact on practice statements: This study yields new data on dalteparin in RI, which has not been widely studied before.

Tinzaparin Sodium Pharmacokinetics in Patients with Chronic Kidney Disease: Practical Implications

Low-molecular-weight heparins (LMWHs) are the mainstay of the prophylaxis and treatment of venous thromboembolism (VTE). Due to their renal elimination, the risk of accumulation with the related bleeding risk may represent a limitation for the use of LMWHs in patients with chronic kidney disease (CKD) as the risk of major bleeding is increased in patients with creatinine clearance (CrCl) < 30 mL/min, especially in patients with cancer. LMWH structure and molecular weight (MW) are heterogeneous among available agents. The elimination of tinzaparin, which has the highest mean MW among LMWHs, is less dependent on renal function as it is also metabolized through the reticuloendothelial system. A subcutaneous therapeutic dose of tinzaparin (175 IU/kg) once daily has been shown to cause no accumulation of anti-factor Xa activity in patients with CrCl ≥ 20 mL/min. Clinical experience from randomized controlled studies has shown no significant impact of CKD on bleeding risk in cancer patients receiving treatment doses of tinzaparin. This suggests that in these patients the use of treatment doses of tinzaparin does not require anticoagulation monitoring or dose adjustment.

Prophylaxis and Therapy of Venous Thrombotic Events (VTE) in Pregnancy and the Postpartum Period

Venous thromboembolisms and pulmonary embolisms are one of the main causes of morbidity and mortality in pregnancy. The increased risk of thrombotic events caused by the physiological changes during pregnancy alone does not justify any medical antithrombotic prophylaxis. However, if there are also other risk factors such as a history of thromboses, hormonal stimulation as part of fertility treatment, thrombophilia, increased age of the pregnant woman, severe obesity or predisposing concomitant illnesses, the risk of thrombosis should be re-evaluated - if possible by a coagulation specialist - and drug prophylaxis should be initiated, where applicable. Low-molecular-weight heparins (LMWH) are the standard medication for the prophylaxis and treatment of thrombotic events in pregnancy and the postpartum period. Medical thrombosis prophylaxis started during pregnancy is generally continued for about six weeks following delivery due to the risk of thrombosis which peaks during the postpartum period. The same applies to therapeutic anticoagulation after the occurrence of a thrombotic event in pregnancy; here, a minimum duration of the therapy of three months should also be adhered to. During breastfeeding, LMWH or the oral anticoagulant warfarin can be considered; neither active substance passes into breast milk.

Association Between Low-Molecular-Weight Heparin and Risk of Bleeding Among Hemodialysis Patients: A Retrospective Cohort Study

Background:

Low-molecular-weight heparins (LMWH) replaced unfractionated heparin (UFH) in multiple indications. Although LMWH efficacy in hemodialysis was demonstrated through multiple studies, their safety remains controversial. The potential bioaccumulation in patients undergoing chronic hemodialysis raised the question of bleeding risk among this population.

Objective:

The aim of this study was to evaluate bleeding risk among patients with chronic hemodialysis receiving LMWH or UFH for the extracorporeal circuit anticoagulation.

Design:

We conducted a retrospective cohort study on data extracted from the Régie de l’assurance maladie du Québec (RAMQ) and Med-Echo databases from January 2007 to March 2013.

Setting:

Twenty-one hemodialysis centers in the province of Québec, Canada.

Patients:

Chronic hemodialysis patients.

Measurements:

Bleeding risk evaluated by proportional Cox model for time-dependent exposure using demographics, comorbidities, and drug use as covariates.

Methods:

Minor, major, and total bleeding events identified using International Classification of Diseases, Ninth Revision (ICD-9)/International Classification of Diseases, Tenth Revision (ICD-10) codes in the RAMQ and Med-Echo databases. Exposure status to LMWH or UFH was collected through surveys at the facility level.

Results:

We identified 5322 prevalent and incident patients with chronic hemodialysis. The incidence rate for minor, major, and total bleeding was 9.45 events/1000 patient-year (95% confidence interval [CI]: 7.61-11.03), 24.18 events/1000 patient-year (95% CI: 21.52-27.08), and 32.88 events/1000 patient-year (95% CI: 29.75-36.26), respectively. We found similar risks of minor adjusted hazard ratio (HR: 1.04; 95% CI: 0.68-1.61), major (HR: 0.83; 95% CI: 0.63-1.10), and total bleeding (HR: 0.90; 95% CI: 0.72-1.14) when comparing LMWH with UFH.

Limitations:

Potential misclassification of patients’ exposure status and possible underestimation of minor bleeding risk.

Conclusion:

LMWH was not associated with a higher minor, major, or total bleeding risk. LMWH did not increase the risk of bleeding compared with UFH for the extracorporeal circuit anticoagulation in hemodialysis. The convenience of use and predictable effect made LMWH a suitable alternative to UFH in hemodialysis.

The Role of Tinzaparin in Oncology

Current guidelines recommend low-molecular-weight heparin treatment in patients with cancer with established venous thromboembolism (VTE). The aim of this article was to study the pharmacological properties and effectiveness of tinzaparin in patients with cancer as well as its potential anticancer properties. A search of PubMed and ScienceDirect databases up to March 2016 was carried out to identify published studies that detect the properties and use of tinzaparin in oncology. Protamine sulfate partially (60% to 65%) neutralized tinzaparin’s anti-Xa activity. No dose adjustment of tinzaparin is needed even in patients with severe renal impairment and Creatinine Clearance ≥20 mL/min. Tinzaparin demonstrated a statistically significant decline in VTE recurrence at 1 year post the index thromboembolic event. A statistically significant reduction in minor bleeding rates was also described, whereas major bleeding events did not decrease in patients with cancer treated with tinzaparin versus those who received vitamin K antagonists. Tinzaparin treatment in patients suffering from deep vein thrombosis reduced the incidence of postthrombotic syndrome and venous ulcers. Tinzaparin’s ability to prevent both metastatic dissemination of cancer cells and tumor angiogenesis has been delineated in preclinical research. Current data show that tinzaparin is safe and efficacious either for short-term or for long-term treatment of VTE in patients with cancer. Clinical trials are needed in order to examine the utility of tinzaparin in primary prevention of VTE and validate its potential anticancer advantages exhibited in preclinical research.

Safety of low-molecular-weight heparin compared to unfractionated heparin in hemodialysis: a systematic review and meta-analysis

BACKGROUND

Low molecular weight heparins (LMWH) have been extensively studied and became the treatment of choice for several indications including pulmonary embolism. While their efficacy in hemodialysis is considered similar to unfractionated heparin (UFH), their safety remains controversial mainly due to a risk of bioaccumulation in patients with renal impairment. The aim of this systematic review was to evaluate the safety of LMWH when compared to UFH for extracorporeal circuit (ECC) anticoagulation.

METHODS

We used Pubmed, Embase, Cochrane central register of controlled trials, Trip database and NICE to retrieve relevant studies with no language restriction. We looked for controlled experimental trials comparing LMWH to UFH for ECC anticoagulation among end-stage renal disease patients undergoing chronic hemodialysis. Studies were kept if they reported at least one of the following outcomes: bleeding, lipid profile, cardiovascular events, osteoporosis or heparin-induced thrombocytopenia. Two independent reviewers conducted studies selection, quality assessment and data extraction with discrepancies solved by a third reviewer. Relative risk and 95% CI was calculated for dichotomous outcomes and mean weighted difference (MWD) with 95% CI was used to pool continuous variables.

RESULTS

Seventeen studies were selected as part of the systematic. The relative risk for total bleeding was 0.76 (95% CI 0.26-2.22). The WMD calculated for total cholesterol was -28.70 mg/dl (95% CI -51.43 to -5.98), a WMD for triglycerides of -55.57 mg/dl (95% CI -94.49 to -16.66) was estimated, and finally LDL-cholesterol had a WMD of -14.88 mg/dl (95% CI -36.27 to 6.51).

CONCLUSIONS

LMWH showed to be at least as safe as UFH for ECC anticoagulation in chronic hemodialysis. The limited number of studies reporting on osteoporosis and HIT does not allow any conclusion for these outcomes. Larger studies are needed to evaluate properly the safety of LMWH in chronic hemodialysis.

Long-term treatment of cancer-associated thrombosis: the choice of the optimal anticoagulant

Patients with cancer-associated thrombosis (CAT) carry a higher risk of recurrence, bleeding and mortality as compared with non-cancer patients. The specific profiles of cancer patients, combining frequent co-morbidities, the use of anti-tumoral therapies and the cancer progression itself, represent a major therapeutic challenge for choosing a long-term anticoagulant treatment. This review discusses the practical basis of making a choice between the available drugs for a long-term antithrombotic strategy, linked to their pharmacology, mechanism of action, evidence of clinical benefits, and advantages and limitations in such a complex clinical context. In patients with cancer, low-molecular-weight heparins (LMWHs) are the preferred option for the secondary prevention of venous thromboembolism according to current guidelines, because their efficacy is significantly superior to vitamin K antagonists (VKAs). Even though LMWHs are effective and safe in cancer patients, they require daily subcutaneous injections, which may be problematic for a long-term therapy that may exceed 6 months' duration. Compared with VKAs, non-vitamin-K antagonist oral anticoagulants or direct oral anticoagulants (DOACs) are more target specific and do not require laboratory monitoring, whereas the oral route of administration makes them potentially attractive alternatives to LMWH. In randomized controlled trials in the general population DOACs have been shown to be non-inferior to VKAs in terms of efficacy with a lower rate of clinically relevant or major bleeding. However, given the limited number of cancer patients enrolled in these studies (with poorly defined active cancer), available trials are inconclusive regarding the usefulness of DOACs in the cancer setting. Ongoing head-to-head comparisons vs. LMWH in patients with CAT may allow an informed choice to be made regarding the DOAC option.

A post hoc analysis of dalteparin versus oral anticoagulant (VKA) therapy for the prevention of recurrent venous thromboembolism (rVTE) in patients with cancer and renal impairment

Venous thromboembolism (VTE) is a common and serious complication in patients with cancer; treatment guidelines recommend extended therapy of ≥6 months with low-molecular-weight heparin (LMWH) for treatment and prevention of recurrent VTE (rVTE) in this population. This post hoc analysis used data from the CLOT study—a phase III, randomized, open-label, controlled study (N = 676)—to compare the efficacy and safety of dalteparin, a LMWH, versus vitamin K antagonist (VKA) for prevention of rVTE in patients with cancer and renal impairment (creatinine clearance <60 ml/min). Overall, 162/676 (24 %) patients had renal impairment at baseline. Patients received subcutaneous dalteparin 200 IU/kg once daily during month 1, followed by 150 IU/kg once daily for months 2–6; or VKA once daily for 6 months, with initial overlapping subcutaneous dalteparin 200 IU/kg once daily for ≥5 days until international normalized ratio was 2.0–3.0 for 2 consecutive days. Endpoints included the rates of rVTE (primary) and bleeding events. Overall, fewer dalteparin-treated patients (2/74 [2.7 %]) experienced ≥1 adjudicated symptomatic rVTE compared with VKA-treated patients (15/88 [17.0 %]; hazard ratio = 0.15 [95 % confidence interval 0.03–0.65]; p = 0.01). Bleeding event rates for both treatments were similar (p = 0.47). In summary, compared with VKA, dalteparin significantly reduced risk of rVTE in patients with cancer and renal impairment (p = 0.01) while exhibiting a comparable safety profile. This analysis supports dosing patients with renal impairment in accordance with patients with normal renal function; however, anti-Xa monitoring could be considered to further support safety in selected patients, particularly those with very severe renal impairment.

Treatment with Dalteparin is Associated with a Lower Risk of Bleeding Compared to Treatment with Unfractionated Heparin in Patients with Renal Insufficiency

BACKGROUND

Low molecular weight heparins (LMWHs) have been cautiously used in patients with chronic kidney disease (CKD) due to fear of accumulation. Dalteparin, however, has shown minimal tendency to accumulate in patients with CKD and may be safe to use in this patient population.

OBJECTIVE

We compared the incidence of clinically significant bleeding in patients with CKD receiving therapeutic doses of dalteparin to that of patients with CKD receiving therapeutic doses of UFH.

DESIGN

This was a retrospective cohort study.

SUBJECTS

Inpatients with CKD (GFR < 60 ml/min) who were treated with therapeutic dalteparin or UFH were included in the study

MAIN MEASURES

Primary outcome was major bleeding within 10 days of anticoagulation, identified by ICD-9 code and confirmed by chart review. Demographic characteristics, laboratory values, comorbidities, prior bleeding history and inpatient medications were extracted for each admission from the electronic medical record. Logistic regression models were created to examine the association between choice of anticoagulant and bleeding rates, after adjustment for demographic and clinical characteristics.

KEY RESULTS

Dalteparin-treated patients were significantly less likely to experience a major bleed than patients treated with UFH (1.14 % vs. 3.49 %, p < 0.001). The reduced likelihood of bleeding associated with dalteparin treatment remained significant after adjustment for patient characteristics (HR 0.39, 95 % CI: 0.21-0.70, p < 0.0001). A stratified analysis for subgroups with GFR< 30 mL/min and with GFR between 30 and 60 mL/min showed that dalteparin was still associated with lower odds of bleeding compared to treatment with unfractionated heparin, but the difference was nonsignificant for GFR< 30 (HR 0.35, 95 % CI: 0.11-1.15), even after adjustment (OR 0.37, 95 % CI: 0.11-1.22).

CONCLUSION

In patients with CKD, treatment with therapeutic dose dalteparin was associated with lower rates of bleeding than treatment with unfractionated heparin. For patients with severe CKD (GFR< 30), dalteparin was shown to be at least as safe as unfractionated heparin.

Pharmacology of Heparin and Related Drugs

Heparin has been recognized as a valuable anticoagulant and antithrombotic for several decades and is still widely used in clinical practice for a variety of indications. The anticoagulant activity of heparin is mainly attributable to the action of a specific pentasaccharide sequence that acts in concert with antithrombin, a plasma coagulation factor inhibitor. This observation has led to the development of synthetic heparin mimetics for clinical use. However, it is increasingly recognized that heparin has many other pharmacological properties, including but not limited to antiviral, anti-inflammatory, and antimetastatic actions. Many of these activities are independent of its anticoagulant activity, although the mechanisms of these other activities are currently less well defined. Nonetheless, heparin is being exploited for clinical uses beyond anticoagulation and developed for a wide range of clinical disorders. This article provides a "state of the art" review of our current understanding of the pharmacology of heparin and related drugs and an overview of the status of development of such drugs.

Cancer-associated thrombosis: an overview

Venous thromboembolism (VTE) is a common complication in patients with malignant disease. Emerging data have enhanced our understanding of cancer-associated thrombosis, a major cause of morbidity and mortality in patients with cancer. In addition to VTE, arterial occlusion with stroke and anginal symptoms is relatively common among cancer patients, and is possibly related to genetic predisposition. Several risk factors for developing venous thrombosis usually coexist in cancer patients including surgery, hospital admissions and immobilization, the presence of an indwelling central catheter, chemotherapy, use of erythropoiesis-stimulating agents (ESAs) and new molecular-targeted therapies such as antiangiogenic agents. Effective prophylaxis and treatment of VTE reduced morbidity and mortality, and improved quality of life. Low-molecular-weight heparin (LMWH) is preferred as an effective and safe means for prophylaxis and treatment of VTE. It has largely replaced unfractionated heparin (UFH) and vitamin K antagonists (VKAs). Recently, the development of novel oral anticoagulants (NOACs) that directly inhibit factor Xa or thrombin is a milestone achievement in the prevention and treatment of VTE. This review will focus on the epidemiology and pathophysiology of cancer-associated thrombosis, risk factors, and new predictive biomarkers for VTE as well as discuss novel prevention and management regimens of VTE in cancer according to published guidelines.

Evidence-based guidance on venous thromboembolism in patients with solid tumours

Venous thromboembolism (vte) is a serious, life-threatening complication of cancer. Anticoagulation therapy such as low molecular weight heparin (lmwh) has been shown to treat and prevent vte. Cancer therapy is often complex and ongoing, making the management of vte less straightforward in patients with cancer. There are no published Canadian guidelines available to suggest appropriate strategies for the management of vte in patients with solid tumours. We therefore aimed to develop a clear, evidence-based guideline on this topic. A systematic review of clinical trials and meta-analyses published between 2002 and 2013 in PubMed was conducted. Reference lists were hand-searched for additional publications. The National Guidelines Clearinghouse was searched for relevant guidelines. Recommendations were developed based on the best available evidence. In patients with solid tumours, lmwh is recommended for those with established vte and for those without established vte but with a high risk for developing vte. Options for lmwh include dalteparin, enoxaparin, and tinzaparin. No one agent can be recommended over another, but in the setting of renal insufficiency, tinzaparin is preferred. Unfractionated heparin can be used under select circumstances only (that is, when rapid clearance of the anticoagulant is desired). The most common adverse event is bleeding, but major events are rare, and with appropriate follow-up care, bleeding can be monitored and appropriately managed.

What is the Best Treatment for a Cancer Patient with Thrombosis?

The relationship between venous thromboembolism and cancer has been known for many years, and there is solid scientific evidence addressing the adequate treatment of this condition in oncology patients. However, established prescribing habits, individual patient challenges, and uncertainty concerning treatment justifies poor adherence to published guidelines. This paper reviews venous thromboembolism treatment while focusing on vitamin K antagonists, low-molecular-weight heparins, and novel oral anticoagulants, namely in terms of their efficacy and limitations.