Low-molecular-weight or unfractionated heparin in venous thromboembolism: the influence of renal function

Tinzaparin, an alternative to subcutaneous unfractionated heparin, in patients with severe and end-stage renal impairment: a retrospective observational single-center study

BACKGROUND

Tinzaparin could be easier to manage than unfractionated heparin in patients with severe renal impairment. However, clinical and pharmacologic data regarding its use in such patients are lacking.

OBJECTIVES

The aims of this study were to determine, in patients with estimated glomerular filtration rate (eGFR) of <30 mL.min⁻1, tinzaparin pharmacokinetics (PK) parameters using a population PK approach and bleeding and thrombotic complications.

METHODS

We performed a retrospective observational single-center study, including in-patients with eGFR of <30 mL.min⁻1 receiving prophylactic (4500 IU.d⁻1) or therapeutic (175 IU.kg⁻1.d⁻1) tinzaparin. Measured anti-Xa levels were analyzed using a nonlinear mixed-effects modeling approach. Individual predicted tinzaparin exposure markers at steady state were calculated for each patient and dosing regimen. The PK was also evaluated through Monte Carlo simulations based on the final covariate model parameter estimates.

RESULTS

Over a 22-month period, 802 tinzaparin treatment periods in 623 patients were analyzed: two-thirds received a prophylactic dose, 66% had an eGFR of <20 mL.min⁻1, and 25% were on renal replacement therapy. In patients for whom anti-Xa measurements were performed (n = 199; 746 values), PK parameters, profiles, and maximum plasma concentrations were comparable with those in patients without renal impairment or in healthy volunteers. In the whole population, major bleeding occurred in 2.4% and 3.5% of patients receiving prophylactic and therapeutic doses over a median 9- and 7-day treatment period, respectively. No patients had thrombotic complications.

CONCLUSION

Tinzaparin PK parameters and profiles were not affected by renal impairment. This suggests that tinzaparin, at therapeutic or prophylactic dose, could be an alternative to unfractionated heparin in hospitalized patients with severe renal impairment.

Anticoagulation in Chronic Kidney Disease

The nuanced landscape of anticoagulation therapy in patients with chronic kidney disease (CKD) presents a formidable challenge, intricately balancing the dual hazards of hemorrhage and thrombosis. These patients find themselves in a precarious position, teetering on the edge of these risks due to compromised platelet functionality and systemic disturbances within their coagulation frameworks. The management of such patients necessitates a meticulous approach to dosing adjustments and vigilant monitoring to navigate the perilous waters of anticoagulant therapy. This is especially critical considering the altered pharmacokinetics in CKD, where the clearance of drugs is significantly impeded, heightening the risk of accumulation and adverse effects. In the evolving narrative of anticoagulation therapy, the introduction of direct oral anticoagulants (DOACs) has heralded a new era, offering a glimmer of hope for those navigating the complexities of CKD. These agents, with their promise of easier management and a reduced need for monitoring, have begun to reshape the contours of care, particularly for patients not yet on dialysis. However, this is not without its caveats. The application of DOACs in the context of advanced CKD remains a largely uncharted territory, necessitating a cautious exploration to unearth their true potential and limitations. Moreover, the advent of innovative strategies such as left atrial appendage occlusion (LAAO) underscores the dynamic nature of anticoagulation therapy, potentially offering a tailored solution for those at the intersection of CKD and elevated stroke risk. Yet the journey toward integrating such advancements into standard practice is laden with unanswered questions, demanding rigorous investigation to illuminate their efficacy and safety across the spectrum of kidney disease. In summary, the management of anticoagulation in CKD is a delicate dance, requiring a harmonious blend of precision, caution, and innovation. As we venture further into this complex domain, we must build upon our current understanding, embracing both emerging therapies and the need for ongoing research. Only then can we hope to offer our patients a path that navigates the narrow strait between bleeding and clotting, toward safer and more effective care.

Enoxaparin for Long-Term Therapy of Venous Thromboembolism in Patients with Cancer and Renal Insufficiency

BACKGROUND

 The optimal therapy of venous thromboembolism (VTE) in cancer patients with renal insufficiency (RI) is unknown. Current guidelines recommend to use low-molecular-weight heparin over direct oral anticoagulants to treat VTE in cancer patients at high risk of bleeding.

METHODS

 We used the Registro Informatizado Enfermedad Tromboemb00F3lica (RIETE) registry to compare the 6-month incidence rates of (1) VTE recurrences versus major bleeding and (2) fatal pulmonary embolism (PE) versus fatal bleeding in three subgroups (those with mild, moderate, or severe RI) of cancer patients receiving enoxaparin monotherapy.

RESULTS

 From January 2009 through June 2022, 2,844 patients with RI received enoxaparin for ≥6 months: 1,432 (50%) had mild RI, 1,168 (41%) moderate RI, and 244 (8.6%) had severe RI. Overall, 68, 62, and 12%, respectively, received the recommended doses. Among patients with mild RI, the rates of VTE recurrences versus major bleeding (4.6 vs. 5.4%) and fatal PE versus fatal bleeding (1.3 vs. 1.2%) were similar. Among patients with moderate RI, VTE recurrences were half as common as major bleeding (3.1 vs. 6.3%), but fatal PE and fatal bleeding were close (1.8 vs. 1.2%). Among patients with severe RI, VTE recurrences were threefold less common than major bleeding (4.1 vs. 13%), but fatal PE was threefold more frequent than fatal bleeding (2.5 vs. 0.8%). During the first 10 days, fatal PE was fivefold more common than fatal bleeding (2.1 vs. 0.4%).

CONCLUSION

 Among cancer patients with severe RI, fatal PE was fivefold more common than fatal bleeding. The recommended doses of enoxaparin in these patients should be revisited.

A Biomimicking and Multiarm Self-Indicating Nanoassembly for Site-Specific Photothermal-Potentiated Thrombolysis Assessed in Microfluidic and In Vivo Models

Thrombolytic and antithrombotic therapies are limited by short circulation time and the risk of off-target hemorrhage. Integrating a thrombus-homing strategy with photothermal therapy are proposed to address these limitations. Using glycol chitosan, polypyrrole, iron oxide and heparin, biomimicking GCPIH nanoparticles are developed for targeted thrombus delivery and thrombolysis. The nanoassembly achieves precise delivery of polypyrrole, exhibiting biocompatibility, selective accumulation at multiple thrombus sites, and enhanced thrombolysis through photothermal activation. To simulate targeted thrombolysis, a microfluidic model predicting thrombolysis dynamics in realistic pathological scenarios is designed. Human blood assessments validate the precise homing of GCPIH nanoparticles to activated thrombus microenvironments. Efficient near-infrared phototherapeutic effects are demonstrated at thrombus lesions under physiological flow conditions ex vivo. The combined investigations provide compelling evidence supporting the potential of GCPIH nanoparticles for effective thrombus therapy. The microfluidic model also offers a platform for advanced thrombolytic nanomedicine development.

Pulmonary Embolism in the Cancer Associated Thrombosis Landscape

In cancer patients, pulmonary embolism (PE) is the second leading cause of death after the cancer itself, most likely because of difficulties in diagnosing the disease due to its nonclassical presentation. The risk of PE recurrence and possibly the case-fatality rate depends on whether the patient presents a symptomatic PE, an unsuspected PE, a subsegmental PE, or a catheter-related PE. Choosing the best therapeutic option is challenging and should consider the risk of both the recurrence of thrombosis and the occurrence of bleeding. The purpose of this review is to provide an overview of the clinical characteristics and the treatment of cancer-associated PE, which could benefit clinicians to better manage the deadliest form of thrombosis associated with cancer. After a brief presentation of the epidemiological data, we will present the current attitude towards the diagnosis and the management of cancer patients with PE. Finally, we will discuss the perspectives of how the medical community can improve the management of this severe medical condition.

Long-term clinical outcomes in older patients with acute venous thromboembolism who have renal impairment

INTRODUCTION

Renal impairment (RI) may induce an inflammatory/procoagulant state as well as platelet dysfunction. Little is known on the prevalence of RI and long-term prognosis of older patients with venous thromboembolism (VTE) who have concomitant RI.

METHODS

In a prospective multicenter cohort, we analyzed 912 patients aged ≥65 years with acute VTE. Using the CKD-EPI formula, we defined three categories of baseline renal function: estimated glomerular filtration rate ≥60 ml/min/1.73m² (no RI), 30-59 ml/min/1.73m² (moderate RI), and <30 ml/min/1.73m² (severe RI). The outcomes were VTE recurrence, major bleeding, and overall mortality. We examined the association between renal function and clinical outcomes using competing risk regression models, adjusting for relevant confounders and periods of anticoagulation.

RESULTS

We followed 912 patients over a median duration of 29.6 months. Overall, 313 (34%) patients had moderate and 51 (6%) severe RI. One hundred and seven patients (12%) had VTE recurrence, 125 (14%) had major bleeding, and 186 (20%) died during follow-up. After adjustment, severe RI was associated with a 2-fold increased risk of major bleeding (sub-hazard ratio [SHR] 2.1, 95% CI 1.1-4.0) compared to no RI, but not with VTE recurrence (SHR 0.6, 95% CI 0.2-1.8) or overall mortality (hazard ratio 1.0, 95% CI 0.6-1.9). Moderate RI was not significantly associated with adverse clinical outcomes.

CONCLUSIONS

RI was common among older patients with acute VTE. Severe RI was associated with a 2-fold increased long-term risk of major bleeding, without a risk increase in terms of VTE recurrence and overall mortality. Older patients with moderate RI did not carry worse prognosis.

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.

LMWHs dosage and outcomes in acute pulmonary embolism with renal insufficiency, an analysis from a large real-world study

Background

Renal function is associated with prognoses for acute pulmonary embolism (PE).

Objective

To investigate the application of anticoagulants and dosage of LMWH among patients with renal insufficiency (RI), and the association between LWMH dosage and the patients’ in-hospital outcomes.

Methods

Adult patients diagnosed with non-high risk acute PE from 2009 to 2015, with available data of creatinine clearance (CCr) were enrolled from a multicenter registry in China. Renal insufficiency (RI) was defined as CCr < 60 ml/min. LMWH dosage was converted into IU/kg daily dose and presented as adjusted dose (≤ 100 IU/kg/day) and conventional dose (> 100 IU/kg/day). All-cause death, PE-related death and bleeding events during hospitalization were analyzed as endpoints.

Results

Among the enrolled 5870 patients, RI occurred in 1311 (22.3%). 30 ≤ CCr < 60 ml/min was associated with higher rate of bleeding events and CCr < 30 ml/min was associated with all-cause death, PE-related death and major bleeding. Adjusted-dose LMWH was applied in 26.1% of patients with 30 ≤ CCr < 60 ml/min and in 26.2% of CCr < 30 ml/min patients. Among patients with RI, in-hospital bleeding occurred more frequently in those who were administered conventional dose of LMWH, compared with adjusted dose (9.2% vs 5.0%, p = 0.047). Adjusted dose of LMWH presented as protective factor for in-hospital bleeding (OR 0.62, 95%CI 0.27–1.00, p = 0.0496) and the risk of bleeding increased as length of hospital stay prolonged (OR 1.03, 95%CI 1.01–1.06, p = 0.0014).

Conclusions

The proportion of adjusted usage of LMWH was low. The application of adjusted-dose LMWH was associated with lower risk of in-hospital bleeding for RI patients, in real-world setting of PE treatment. Anticoagulation strategy for RI patients should be paid more attention and requires evidence of high quality.

Trial Registration

The CURES was registered in ClinicalTrias.gov, identifier number: NCT02943343.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00385-z.

Performance Characteristics of DOAC Dipstick in Determining Direct Oral Anticoagulants in Urine

Testing for direct oral anticoagulants (DOACs) in patient urine may facilitate medical treatment decisions. The aim of this study was to investigate interobserver variability by 2 independent observers compared to laboratory staff in the visual interpretation of factor Xa (DXI) and thrombin inhibitors (DTI) using the DOAC Dipstick test. We also examined whether test pads reacted to other anticoagulants and abnormal urine colors. The colors of the DOAC Dipstick direct factor Xa inhibitor and thrombin inhibitor pads were interpreted with 100% accuracy (95% confidence interval 0.862 to 1.000) for urine samples from persons treated with apixaban (n = 26), rivaroxaban (n = 24), and dabigatran (n = 29) and without anticoagulant therapy (n = 29). The factor Xa and thrombin inhibitor pads did not interact with heparin, nadroparin, fondaparinux, or coumadin. One µg/mL r-Hirudin and 6 µg/mL argatroban interacted with the DTI pad; however, this is unlikely to cause clinical problems because dabigatran is unlikely to be administered together with r-Hirudin and argatroban in clinical circumstances. Abnormal urine color was reliably detected by the urine color pad, so can prevent false interpretation of the DOAC Dipstick pad colors. In conclusion, we have demonstrated that interobserver variability when interpreting the DOAC Dipstick test strip is low and that factor Xa and thrombin inhibitor pads do not react to other anticoagulants such as heparins and coumadin. R-Hirudin and argatroban can be detected by the thrombin inhibitor pad and abnormal urine colors can be detected by the urine color pad to prevent false interpretation of the results in patient urine samples.

Severe renal impairment and risk of bleeding during anticoagulation for venous thromboembolism

BACKGROUND

Detection of severe renal impairment in patients with venous thromboembolism (VTE) is mandatory both for selecting anticoagulant therapy and for evaluating major bleeding risk, increased by severe renal impairment.

OBJECTIVES

To determine whether the Cockcroft and Gault (CG) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas identify severe renal impairment in the same VTE patients presenting the same risk of major bleeding.

PATIENTS/METHODS

We compared clinical characteristics and outcomes during the first 3 months of anticoagulation between VTE patients in the RIETE registry with severe renal impairment according to the CG and/or CKD-EPI formula (estimated glomerular filtration rate <30 mL/min and <30 mL/min/1.73 m2 , respectively). The primary outcome was major bleeding.

RESULTS

Up to October 2017, 41 796 patients were included in RIETE. Among the 4676 patients with severe renal impairment according to at least one of the formulas, this was not confirmed by the other formula in 1904 (40.7%). Major bleeding risk was increased in every patient subgroup with severe renal impairment vs patients without this condition (CG or CKD-EPI < 30: odds ratio [OR] = 2.26, 95% confidence interval [CI 2.01-2.53], only CG < 30: OR = 1.72, 95% CI [1.37-2.13], only CKD-EPI < 30: OR = 2.34, 95% CI [1.77-3.05], CG+CKD-EPI < 30: OR = 2.47, 95% CI [2.16-2.83], all vs CG+CKD-EPI > 30).

CONCLUSION

The CG and CKD-EPI formulas identify different subgroups of patients with severe renal impairment, leading to discordant results in 40.7% of these patients. Irrespective of the formula used for their identification, patients with severe renal impairment have a higher risk of major bleeding under anticoagulant therapy.

Pros and cons of antithrombotic therapy in end-stage kidney disease: a 2019 update

Dialysis patients manifest both an increased thrombotic risk and a haemorrhagic tendency. A great number of patients with chronic kidney disease requiring dialysis have cardiovascular comorbidities (coronary artery disease, atrial fibrillation or venous thromboembolism) and different indications for treatment with antithrombotics (primary or secondary prevention). Unfortunately, few randomized controlled trials deal with antiplatelet and/or anticoagulant therapy in dialysis. Therefore cardiology and nephrology guidelines offer ambiguous recommendations and often exclude or ignore these patients. In our opinion, there is a need for an expert consensus that provides physicians with useful information to make correct decisions in different situations requiring antithrombotics. Herein the European Dialysis Working Group presents up-to-date evidence about the topic and encourages practitioners to choose among alternatives in order to limit bleeding and minimize atherothrombotic and cardioembolic risks. In the absence of clear evidence, these clinical settings and consequent therapeutic strategies will be discussed by highlighting data from observational studies for and against the use of antiplatelet and anticoagulant drugs alone or in combination. Until new studies shed light on unclear clinical situations, one should keep in mind that the objective of treatment is to minimize thrombotic risk while reducing bleeding events.

Clinical patterns and significance of non-compliance with guideline-recommended treatment of acute pulmonary embolism

BACKGROUND

Evidence-based clinical practice guidelines define initial management of acute pulmonary embolism (PE) according to risk stratification for early death.

AIMS

The aims of the present study were to investigate patterns of non-compliance with guidelines for the acute PE treatment, and the associated risk of adverse events.

METHODS

We performed an observational, multicentre, cohort study of acute PE. Inclusion criteria were all patients with pulmonary embolism admitted to the participating centres between January 2011 and April 2017. The measure of 100% compliance was used to allocate patients in the compliant or non-compliant groups. The primary outcome was all-cause death at 6 months. Secondary outcomes included recurrent venous thromboembolism and major bleeding.

RESULTS

In total, 1285 patients were included. Treatment was not in compliance with the guidelines in 172 patients (13.4%). Four factors were identified to be related to non-compliance with the guidelines: shock or hypotension (relative risk [RR] 5.23, 95% confidence interval [CI] 2.64-10.30; P<0.001), renal insufficiency (RR 1.80, 95% CI 1.41-2.28; P<0.001), active cancer (RR 1.35, 95% CI 1.24-1.48; P<0.001) and right ventricular dysfunction at admission (RR 1.06, 95% CI 1.01-1.11; P=0.01). The primary endpoint of all-cause death at 6 months occurred in 62 of 172 patients (36.0%) in the non-compliant group and in 131 of 1113 patients (11.8%) in the compliant group (hazard ratio 2.02, 95% CI 1.45-2.81; P<0.001). The rates of recurrent venous thromboembolism (8.7% vs 1.1%; P<0.001) and major bleeding (13.4% vs 4.9%, P=0.04) from admission to 6-month follow-up were higher in the non-compliant group.

CONCLUSION

Non-compliance with guidelines was independently associated with worse outcomes, including death, recurrent venous thromboembolism and bleeding.

Venous Thromboembolism in Special Populations: Preexisting Cardiopulmonary Disease, Cirrhosis, End-Stage Renal Disease, and Asplenia

Venous thromboembolism (VTE) is a common cause of morbidity and mortality. Presence of preexisting conditions, such as cardiopulmonary diseases, cirrhosis, renal dysfunction, and asplenia, commonly occurs in VTE patients. Moreover, these conditions often are risk factors for developing VTE. These preexisting conditions make VTE diagnosis and treatment challenging and worsen outcomes. Current guidelines do not include detailed features in the diagnosis and management of patients with preexisting conditions. This review discusses presence of VTE in patients with preexisting cardiopulmonary diseases, cirrhosis, renal dysfunction, and asplenia.

Comparison of All-Cause Mortality Following VTE Treatment Between Propensity Score-Adjusted Observational Studies and Matched Randomized Controlled Trials: Meta-Epidemiologic Study

BACKGROUND

It is unknown whether propensity score-adjusted observational studies produce results comparable to those of randomized controlled trials (RCTs) that address similar VTE treatment issues.

METHODS

The PubMed and Web of Science databases were systematically searched for propensity score-adjusted observational studies, RCTs, and meta-analyses of RCTs that estimated all-cause mortality following VTE treatment. After identifying distinct clinical treatment issues evaluated in the eligible observational studies, a standardized algorithm was used to identify and match at least one RCT or RCT meta-analysis publication for paired study design analyses. Meta-analyses were used to summarize groups of studies. Treatment efficacy statistics (relative ORs) were compared between the paired observational and RCT studies, and the summary relative ORs for all study design pairs were also calculated.

RESULTS

The observational and RCT study pairs assessed seven clinical treatment issues. Overall, the observational study-RCT pairs did not exhibit significantly different mortality estimates (summary relative OR, 0.89; 95% CI, 0.32-1.46; I2 = 23%). However, two of the seven treatment issue study pairs (thrombolysis vs anticoagulation for pulmonary embolism; once- vs twice-daily enoxaparin for VTE) exhibited a significantly different treatment effect direction, and there was a substantial (nonsignificant) difference in the magnitude of the effect in another two of the study pairs (rivaroxaban vs vitamin K antagonists for VTE; home treatment vs hospitalization for DVT).

CONCLUSIONS

This systematic comparison across seven VTE treatment topics suggests that propensity score-adjusted observational studies and RCTs often exhibit similar all-cause mortality, although differences in the direction or the magnitude of estimated treatment effects may occasionally occur.

TRIAL REGISTRY

PROSPERO; CRD42018087819; URL: http://www.crd.york.ac.uk/PROSPERO.

Enoxaparin 20 mg for thromboprophylaxis in severe renal impairment

Objective

This study was performed to evaluate the efficacy of daily subcutaneous enoxaparin 20 mg in patients with renal failure.

Methods

This retrospective cohort study included nonsurgical patients aged ≥18 years with a creatinine clearance rate of <30 mL/minute who were prescribed enoxaparin 20 mg subcutaneously (SC) daily for ≥3 days. The main outcome measures were the occurrence of a venous thromboembolic event (VTE) and bleeding events.

Results

One hundred sixty patients were identified. VTE occurred in 9 patients (5.6%), and bleeding events occurred in 37 (23.1%). Multivariable analysis showed that an age of >75 years was significantly associated with an increased risk of bleeding, while a creatinine clearance rate of 15 to 29 mL/minute was significantly associated with a lower risk of bleeding.

Conclusion

In patients with renal failure, enoxaparin 20 mg SC daily resulted in a 5.6% incidence of VTE, which is similar to the previously published acceptable incidence of VTE in patients with normal renal function receiving enoxaparin 40 mg SC daily. The incidence of major bleeding events was 10%, which is lower than that previously published in the literature.

Clinical Characteristics and Outcomes of Patients with Lung Cancer and Venous Thromboembolism

Background  The natural history of patients with lung cancer and venous thromboembolism (VTE) has not been consistently evaluated.

Methods  We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to assess the clinical characteristics, time course, and outcomes during anticoagulation of lung cancer patients with acute, symptomatic VTE.

Results  As of May 2017, a total of 1,725 patients were recruited: 1,208 (70%) presented with pulmonary embolism (PE) and 517 with deep vein thrombosis (DVT). Overall, 865 patients (50%) were diagnosed with cancer <3 months before, 1,270 (74%) had metastases, and 1,250 (72%) had no additional risk factors for VTE. During anticoagulation (median, 93 days), 166 patients had symptomatic VTE recurrences (recurrent DVT: 86, PE: 80), 63 had major bleeding (intracranial 11), and 870 died. The recurrence rate was twofold higher than the major bleeding rate during the first month, and over threefold higher beyond the first month. Fifty-seven patients died of PE and 15 died of bleeding. Most fatal PEs (84%) and most fatal bleeds (67%) occurred within the first month of therapy. Nine patients with fatal PE (16%) died within the first 24 hours. Of 72 patients dying of PE or bleeding, 15 (21%) had no metastases and 29 (40%) had the VTE shortly after surgery or immobility.

Conclusion  Active surveillance on early signs and/or symptoms of VTE in patients with recently diagnosed lung cancer and prescription of prophylaxis in those undergoing surgery or during periods of immobilization might likely help prevent VTE better, detect it earlier, and treat it more efficiently.

3-O sulfation of heparin leads to hepatotropism and longer circulatory half-life

INTRODUCTION

Heparins are common blood anticoagulants that are critical for many surgical and biomedical procedures used in modern medicine. In contrast to natural heparin derived from porcine gut mucosa, synthetic heparins are homogenous by mass, polymer length, and chemistry.

MATERIALS & METHODS

Stable cell lines expressing the human and mouse Stabilin receptors were used to evaluate endocytosis of natural and synthetic heparin. We chemoenzymatically produced synthetic heparin consisting of 12 sugars (dodecamers) containing 14 sulfate groups resulting in a non-3-O sulfated structure (n12mer). Half of the n12mer was modified with a 3-O sulfate on a single GlcNS sugar producing the 3-O sulfated heparin (12mer). Wildtype (WT), Stabilin-1 knock-out (KO), and Stabilin-2 KO C57BL/6 mice were developed and used for metabolic studies and provided as a source for primary liver sinusoidal endothelial cells.

RESULTS & CONCLUSIONS

Human and mouse Stabilin-2 receptors had very similar endocytosis rates of both the 12mer and n12mer, suggesting that they are functionally similar in primary cells. Subcutaneous injections of the n12mer and 12mer revealed that the 12mer had a much longer half-life in circulation and a higher accumulation in liver. The n12mer never accumulated in circulation and was readily excreted by the kidneys before liver accumulation could occur. Liver sinusoidal endothelial cells from the Stabilin-2 KO mice had lower uptake rates for both dodecamers, whereas, the Stabilin-1 KO mice had lower endocytosis rates for the 12mer than the n12mer. 3-O sulfation of heparin is correlated to both a longer circulatory half-life and hepatotropism which is largely performed by the Stabilin receptors.

Rationale, Design and Methodology of the Computerized Registry of Patients with Venous Thromboembolism (RIETE)

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a preventable cause of in-hospital death, and one of the most prevalent vascular diseases. There is a lack of knowledge with regards to contemporary presentation, management and outcomes of patients with VTE. Many clinically important subgroups (including the elderly, those with recent bleeding and pregnant patients) have been under-represented in clinical trials. Furthermore, design of clinical trials is challenging in some scenarios, such as in those with hemodynamically unstable PE. RIETE (Registro Informatizado Enfermedad TromboEmbolica) is a large prospective multinational ongoing registry, designed to address these unmet needs using representative data from multiple centres. Initiated in Spain in 2001, RIETE currently includes 179 centres in 24 countries and has enrolled more than 72,000 patients. RIETE has helped characterize the pattern of presentation and outcomes of VTE, including the aforementioned understudied subgroups. RIETE has recently expanded to collect long-term outcome data, and has broadened its inclusion criteria to enrol other forms of venous thrombosis (such as cerebral vein thrombosis and splanchnic vein thrombosis). The RIETE platform is also being used to conduct pragmatic comparative effectiveness studies, including randomized trials. Future steps would focus on collaboration with additional centres across the world, and efforts to ensure the quality and expansion of the registry. In conclusion, RIETE is a large ongoing registry of patients with VTE and other thrombotic conditions. Its results could be helpful for improving our understanding of the epidemiology, patterns of care and outcomes of patients with thrombotic disease.

Meeting Report EuroG20 Meeting on Cancer-Associated Thrombosis (CAT) Bergamo, Italy 7 April 2016

The EuroG20 meeting on cancer-associated thrombosis (CAT) convened in Bergamo, Italy on 7 April 2016 to discuss a selection of controversial topics in CAT management. This satellite meeting besides ICTHIC in Bergamo has the objective to propose an European Guidance on CAT in various complex situations where evidence-based guidelines are lacking, driven by eminence-based thoughts of 20 experts and key opinion leaders in thrombosis from EU area and 8 experts from the rest of the world.

Chronic kidney disease and anticoagulation: from vitamin K antagonists and heparins to direct oral anticoagulant agents

Anticoagulation in patients with impaired kidney function can be challenging since drugs' pharmacokinetics and bioavailability are altered in this setting. Patients with chronic kidney disease (CKD) treated with conventional anticoagulant agents [vitamin K antagonist (VKA), low-molecular weight heparin (LMWH) or unfractionated heparin (UFH)] are at high risk of bleeding events (both non-major and major clinically relevant bleeding). While anticoagulation reduces the risk of thromboembolic events, the co-existing bleeding risk and the fact that the most commonly used anticoagulation agents are eliminated via the kidneys pose additional challenges. More recently, two classes of direct oral anticoagulant agents (DOACs) have been investigated for the prevention and management of venous thromboembolic events: the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban, and the direct thrombin inhibitor dabigatran. In this review, we discuss the complex challenges and the practical considerations associated with the management of anticoagulation treatment in patients with CKD, with a special focus on DOACs.

Past, present, and future perspectives of heparins in clinical settings and the role of impaired renal function

Heparin, whose discovery goes back one hundred years, was first detected as a thromboplastin from liver tissue, and its anticoagulant action was only identified later. The procoagulant action of heparin, which was later characterized as an immunologic reaction by binding to platelet-factor IV, presenting as heparin-induced thrombocytopenia, remains as a side effect. For more than 60 years heparin has been the immediate anticoagulant of choice in many clinical indications. Further development of heparins resulted in the production of low-molecular weight heparins and Fondaparinux, which substituted heparin for many indications and has received many more new indications, including administration for non-anticoagulant purposes. This development is still ongoing and has resulted in more than 300 registered clinical trials at the end of 2015. All types of heparins are still investigated in patients with impairment of renal function to improve the safety of treatment. New therapeutic strategies for the prevention and treatment of thromboembolism, as well as of the non-anticoagulant actions of natural and modified types of heparins, are studied intensively. The clinical study designs include treatment with vitamin-K and non-vitamin K oral anticoagulants. Consequently, heparins, low-molecular weight heparins and Fondaparinux play an important role in the human health care system.

Once versus twice daily enoxaparin for the initial treatment of acute venous thromboembolism

Essentials In venous thromboembolism (VTE), it is uncertain if enoxaparin should be given twice or once daily. We compared the 15- and 30-day outcomes in VTE patients on enoxaparin twice vs. once daily. Patients on enoxaparin once daily had fewer major bleeds and deaths than those on twice daily. The rate of VTE recurrences was similar in both subgroups.

SUMMARY

Background In patients with acute venous thromboembolism (VTE), it is uncertain whether enoxaparin should be administered twice or once daily. Methods We used the RIETE Registry data to compare the 15- and 30-day rates of VTE recurrence, major bleeding and death between patients receiving enoxaparin twice daily and those receiving it once daily. We used propensity score matching to adjust for confounding variables. Results The study included 4730 patients: 3786 (80%) received enoxaparin twice daily and 944 once daily. During the first 15 days, patients on enoxaparin once daily had a trend towards more VTE recurrences (odds ratio [OR], 1.79; 95% confidence interval [CI], 0.55-5.88), fewer major bleeds (OR, 0.42; 95% CI, 0.17-1.08) and fewer deaths (OR, 0.32; 95% CI, 0.13-0.78) than those on enoxaparin twice daily. At day 30, patients on enoxaparin once daily had more VTE recurrences (OR, 2.5; 95% CI, 1.03-5.88), fewer major bleeds (OR, 0.40; 95% CI, 0.17-0.94) and fewer deaths (OR, 0.58; 95% CI, 0.33-1.00). On propensity analysis, patients on enoxaparin once daily had fewer major bleeds at 15 (hazard ratio [HR], 0.30; 95% CI, 0.10-0.88) and at 30 days (HR, 0.16; 95% CI, 0.04-0.68) and also fewer deaths at 15 (HR, 0.37; 95% CI, 0.14-0.99) and at 30 days (HR, 0.19; 95% CI, 0.07-0.54) than those on enoxaparin twice daily. Conclusions Our findings confirm that enoxaparin prescribed once daily results in fewer major bleeds than enoxaparin twice daily, as suggested in a meta-analysis of controlled clinical trials.

The Clinical Course of Venous Thromboembolism May Differ According to Cancer Site

BACKGROUND

We hypothesized that the clinical course of venous thromboembolism in patients with active cancer may differ according to the specificities of primary tumor site.

AIM AND METHODS

We used data from RIETE (international registry of patients with venous thromboembolism) to compare the clinical venous thromboembolism-related outcomes during the course of anticoagulation in patients with one of the 4 more frequent cancers (breast, prostate, colorectal, or lung cancer).

RESULTS

As of September 2014, 3947 cancer patients were recruited, of whom 938 had breast, 629 prostate, 1189 colorectal, and 1191 lung cancer. Overall, 55% had metastatic disease (42%, 36%, 53%, and 72%, respectively). During the course of anticoagulant therapy (mean duration, 139 days), the rate of thromboembolic recurrences was similar to the rate of major bleeding in patients with breast (5.6 [95% confidence interval (CI), 3.8-8.1] vs 4.1 [95% CI, 2.7-5.9] events per 100 patient-years) or colorectal cancer (10 [95% CI, 7.6-13] vs 12 [95% CI, 9.4-15] per 100 patient-years). In contrast, in patients with prostate cancer, the rate of venous thromboembolic recurrences was half the rate of major bleeding (6.9 [95% CI, 4.4-10] vs 13 [95% CI, 9.2-17] events per 100 patient-years), whereas in those with lung cancer, the rate of thromboembolic recurrences was twofold higher than the rate of major bleeding (27 [95% CI, 22-23] vs 11 [95% CI, 8.6-15] per 100 patient-years).

CONCLUSIONS

Significant differences in the clinical profile of venous thromboembolic-related outcomes were observed according to the site of cancer. These findings suggest the development of cancer-specific anticoagulant strategies as an area for further research.

Renal function and venous thromboembolic diseases

Anticoagulant agents have been approved by international regulatory agencies to prevent and treat venous thromboembolism (VTE). However, chronic kidney disease (CKD) is: (1) highly frequent in VTE patients; (2) strongly linked to VTE; and (3) a risk factor for cardiovascular morbidity/mortality and fatal pulmonary embolism. Therefore, an increasing number of patients are presented with CKD and VTE and more and more physicians must face the questions of the management of these patients and that of the handling of anticoagulant agents in CKD patients because of the pharmacokinetic modifications of these drugs in this population. These modifications may lead to overdosage and dose-related side effects, such as bleeding. It is therefore necessary to screen VTE patients for CKD and to modify the doses of anticoagulants, if necessary.

Drug Treatment of Venous Thromboembolism in the Elderly

Half of all patients with acute venous thromboembolism are aged over 70 years; they then face the added hazard of an age-related increase in the incidence of major bleeding. This makes it even more important to weigh the balance of benefit and risk when considering anticoagulant treatment and treatment duration. Traditional treatment with a heparin (usually low molecular weight) followed by a vitamin K antagonist such as warfarin is effective but is often complicated, especially in the elderly. The direct-acting oral anticoagulants (DOACs), i.e. the thrombin inhibitor dabigatran and the factor Xa inhibitors rivaroxaban, apixaban and edoxaban, are given in fixed doses, do not need laboratory monitoring, have fewer drug-drug interactions and are therefore much easier to take. Randomised trials, their meta-analyses and 'real-world' data indicate the DOACs are no less effective than warfarin (are non-inferior) and probably cause less major bleeding (especially intracranial). It seems the relative safety of DOACs extends to age above 65 or 70 years, although bleeding becomes more likely regardless of the chosen anticoagulant. Renal impairment, comorbidities (especially cancer) and interventions are special hazards. Ways to minimise bleeding include patient selection and follow-up, education about venous thromboembolism, anticoagulants, drug interactions, regular checks on adherence and avoiding needlessly prolonged treatment. The relatively short circulating half-lives of DOACs mean that time, local measures and supportive care are the main response to major bleeding. They also simplify the management of invasive interventions. An antidote for dabigatran, idarucizumab, was recently approved by regulators, and a general antidote for factor Xa inhibitors is in advanced development.

Prior thromboprophylaxis and outcome in patients experiencing acute venous thromboembolism after an acute medical illness

BACKGROUND

Even despite the use of thromboprophylaxis, some patients with an acute medical illness develop symptomatic venous thromboembolism (VTE). It is unclear whether the outcome in these patients is different in those in whom prophylaxis was not prescribed.

PATIENTS AND METHODS

We used the RIETE (Registro Informatizado Enfermedad TromboEmbolica) database to compare the 3-month outcome (death, fatal pulmonary embolism, VTE recurrences, major bleeding) of patients with acute VTE after immobilization for an acute medical disease, according to the use of prophylaxis.

RESULTS

Thromboprophylaxis was prescribed in 1313 (37%) of the 3527 patients included in August 2014. Acute infection was the most frequent cause of immobilization. Patients who received prophylaxis were more frequently immobilized in hospital than at home (70% vs. 22%), and fewer patients were immobilized for cancer (13% vs. 22%). During the first 3months of treatment, the rates of all-cause death (23 vs. 21%), fatal PE (2.6 vs. 3.1%), VTE recurrences (2.4% vs. 2.8%), and major bleeding (4.2% for both) did not differ between the two groups. Thromboprophylaxis was not associated with each outcome in multivariate analysis.

CONCLUSIONS

The outcome in patients with VTE provoked by medical immobilization was not influenced by the use of thromboprophylaxis during the period of immobility.

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.

Recent advances in anticoagulant drug delivery

INTRODUCTION

Anticoagulants have been prescribed to patients to prevent deep vein thrombosis or pulmonary embolism. However, because of several problems in anticoagulant therapy, much attention has been directed at developing an ideal anticoagulant, and numerous attempts have been made to develop new anticoagulant delivery systems in recent years.

AREAS COVERED

This review discusses the challenges associated with the recent development of anticoagulants and their delivery systems. Various delivery methods have been developed to improve the use of anticoagulants. Recent advances in anticoagulant delivery and antidote development are also discussed in the context of their current progression states.

EXPERT OPINION

There have been many different approaches to developing the delivery system of anticoagulants. One approach has been to expand the use of new oral agents and develop their antidotes. Reducing the size of heparins to use smaller heparins for delivery, and developing oral or topical heparins are also some of the approaches used. Various physical formulations or chemical modifications are other ways that have enhanced the therapeutic potential of anticoagulant agents. On the whole, recent advances have contributed to increasing the efficacy and safety of anticoagulant clinically and have benefited the field of anticoagulant delivery.

Long-Term Anticoagulant Therapy of Patients with Venous Thromboembolism. What Are the Practices?

Current guidelines of antithrombotic therapy suggest early initiation of vitamin K antagonists (VKA) in non-cancer patients with venous thromboembolism (VTE), and long-term therapy with low-molecular weight heparin (LMWH) for those with cancer. We used data from RIETE (international registry of patients with VTE) to report the use of long-term anticoagulant therapy over time and to identify predictors of anticoagulant choice (regarding international guidelines) in patients with- and without cancer. Among 35,280 patients without cancer, 82% received long-term VKA (but 17% started after the first week). Among 4,378 patients with cancer, 66% received long term LMWH as monotherapy. In patients without cancer, recent bleeding (odds ratio [OR] 2.70, 95% CI 2.26–3.23), age >70 years (OR 1.15, 95% CI 1.06–1.24), immobility (OR 2.06, 95% CI 1.93–2.19), renal insufficiency (OR 2.42, 95% CI 2.15–2.71) and anemia (OR 1.75, 95% CI 1.65–1.87) predicted poor adherence to guidelines. In those with cancer, anemia (OR 1.83, 95% CI 1.64–2.06), immobility (OR 1.51, 95% CI 1.30–1.76) and metastases (OR 3.22, 95% CI 2.87–3.61) predicted long-term LMWH therapy. In conclusion, we report practices of VTE therapy in real life and found that a significant proportion of patients did not receive the recommended treatment. The perceived increased risk for bleeding has an impact on anticoagulant treatment decision.

VTE Registry: What Can Be Learned from RIETE?

The Registro Informatizado de Enfermedad TromboEmbólica (RIETE Registry) is an ongoing, international, prospective registry of consecutive patients with acute venous thromboembolism (VTE) designed to gather and analyze data on treatment patterns and outcomes in patients with acute VTE. It started in Spain in 2001, and 6 years later the database was translated into English with the aim to expand the Registry to other countries. In contrast to randomized controlled trials, there is no imposed experimental intervention: the management is determined solely by physicians. Thus, it provides data on patients with VTE in a real-world situation with an unselected patient population. Data from RIETE are hypothesis-generating and provide feedback from real-world clinical situations. So far, we learned about the natural history of VTE in patients with relative or absolute contraindications to anticoagulant therapy. We also learned interesting aspects on the natural history of VTE, and we built a number of prognostic scores to identify VTE patients at low, moderate, or high risk for adverse outcome.

Sex differences in patients receiving anticoagulant therapy for venous thromboembolism

In patients with venous thromboembolism (VTE), the outcome during the course of anticoagulant therapy may differ according to the patient's sex. We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to compare the rate of VTE recurrences, major bleeding, and mortality due to these events according to sex.As of August 2013, 47,499 patients were enrolled in RIETE, of whom 24,280 (51%) were women. Women were older, more likely presented with pulmonary embolism (PE), and were more likely to have recent immobilization but less likely to have cancer than men. During the course of anticoagulation (mean duration: 253 d), 659 patients developed recurrent deep vein thrombosis (DVT), 576 recurrent PE, 1368 bled, and 4506 died. Compared with men, women had a lower rate of DVT recurrences (hazard ratio [HR]: 0.78; 95% confidence interval [CI]: 0.67-0.91), a similar rate of PE recurrences (HR: 0.98; 95% CI: 0.83-1.15), a higher rate of major bleeding (HR: 1.21; 95% CI: 1.09-1.35), and higher mortality due to PE (HR: 1.24; 95% CI: 1.04-1.47). On multivariable analysis, any influence of sex on the risk for recurrent DVT (HR: 0.88; 95% CI: 0.75-1.03), major bleeding (HR: 1.10; 95% CI: 0.98-1.24), or fatal PE (HR: 1.01; 95% CI: 0.84-1.22) was no longer statistically significant.In conclusion, women had fewer DVT recurrences and more bleeds than men during the course of anticoagulation. These differences were not due to sex, but very likely to other patient characteristics more common in female patients and differences in treatment choice.

Prevalence of renal insufficiency in hospitalised patients with venous thromboembolic events: a retrospective analysis based on 6,725 VTE patients

Renal impairment (RI) is an important factor in the selection of anticoagulant therapy in venous thromboembolic event (VTE) patients. In particular, the risk of bleeding events is higher for VTE patients with a glomerular filtration rate (GFR) below 30 mL/min. The aim of this study was to collect data on the prevalence of RI in hospitalised VTE patients in Germany. Furthermore, we investigated how renal function changed during inpatient treatment. We conducted a retrospective chart review in six German hospitals. All patients with a VTE diagnosis who were treated as inpatients from 2007-2011 were included. Patients were categorised according to their renal function. RI was estimated from serum creatinine values. Persistent RI was defined as an estimated glomerular filtration rate (eGFR) of <30 mL/min over at least 72 hours. Renal function could be determined for 5,710 VTE patients. Of these 21.4% had an eGFR>90 mL/min, 38.1% had an eGFR of 60-89 mL/min, 17.3% had an eGFR of 45-59 mL/min, 12.5% had an eGFR of 30-44 mL/min, 7.2% had an eGFR of 15-29 mL/min and 3.6% of the VTE patients had end-stage renal disease. Persistent severe RI was observed in 74.8% of patients with an eGFR <30 mL/min. Overall, 40.6% of the VTE patients investigated had an eGFR <60 mL/min; 10.8% had an eGFR <30 mL/min. Almost three quarters of RI-VTE patients suffered from persistent severe RI. These results suggest that more than one in ten VTE patients is exposed to a high risk of accumulating anticoagulants; most of these RI patients also face an increased risk of mortality.

Managing venous thromboembolism with novel oral anticoagulants in the elderly and other high-risk patient groups

The novel oral anticoagulants represent a new era of anticoagulation for patients with deep vein thrombosis and pulmonary embolism. These agents may offer advantages to patients in whom the use of traditional anticoagulants is typically challenging, such as elderly patients, patients with renal impairment and those with low body weight. Currently, rivaroxaban and dabigatran are the only approved novel oral anticoagulants for the treatment and secondary prevention of venous thromboembolism. It is likely that additional agents will become available in the near future. This review summarises recent phase III data for these agents, focusing, where possible, on results obtained in frail patients.

Pharmacodynamics assessment of Bemiparin after multiple prophylactic and single therapeutic doses in adult and elderly healthy volunteers and in subjects with varying degrees of renal impairment

INTRODUCTION

Aging and renal impairment may prolong the half-life and lead to accumulation of low molecular weight heparins. Correct dosing is critical to prevent bleeding or thrombosis.

MATERIALS AND METHODS

Open, parallel study. Healthy adult [n=13] and elderly (>65yrs) [n=12] volunteers; and subjects with mild (ClCr≥50 to ≤80mL/min, n=8), moderate (ClCr≥30 to <50mL/min, n=7), and severe (ClCr<30mL/min, n=8) renal impairment received four prophylactic doses (3,500IU/24h) and a single therapeutic dose (115IU/kg) of bemiparin with an interim washout period. Anti-FXa activity and the potential need for dose adjustment were evaluated.

RESULTS

There were statistically significant differences in the severe renal impairment group vs. adult volunteers in all anti-FXa related parameters, but no significant differences in any of the anti-FXa related parameters between the adult and the elderly. Anti-FXa simulations after 10 prophylactic doses predicted mean Amax=0.59IU/mL in subjects with severe renal impairment and 0.33-0.39IU/mL in the rest. Simulations in the severe renal impairment group with dose adjustment (2,500IU/24h) predicted all individual Amax<0.60IU/mL (mean Amax=0.42IU/ml). Simulations after 10 therapeutic doses predicted mean Amax=1.22IU/mL in severe renal impairment group and 0.89-0.98IU/mL in the rest. Simulations in the severe renal impairment group with 75% dose adjustment predicted individual Amax≤1.60IU/mL (mean Amax=0.91IU/mL).

CONCLUSIONS

No dose adjustments are required in elderly with preserved renal function. A dose adjustment of bemiparin is only advisable in patients with severe renal impairment when using prophylactic or therapeutic doses.