Once versus twice daily low molecular weight heparin for the initial treatment of venous thromboembolism

New recommendations on cerebral venous and dural sinus thrombosis from the German consensus-based (S2k) guideline

Over the last years, new evidence has accumulated on multiple aspects of diagnosis and management of cerebral venous and dural sinus thrombosis (CVT) including identification of new risk factors, studies on interventional treatment as well as treatment with direct oral anticoagulants. Based on the GRADE questions of the European Stroke Organization guideline on this topic, the new German guideline on CVT is a consensus between expert representatives of Austria, Germany and Switzerland. New recommendations include:• CVT occurring in the first weeks after SARS-CoV-2 vaccination with vector vaccines may be associated with severe thrombocytopenia, indicating the presence of a prothrombotic immunogenic cause (Vaccine-induced immune thrombotic thrombocytopenia; VITT).• D-dimer testing to rule out CVT cannot be recommended and should therefore not be routinely performed.• Thrombophilia screening is not generally recommended in patients with CVT. It should be considered in young patients, in spontaneous CVT, in recurrent thrombosis and/or in case of a positive family history of venous thromboembolism, and if a change in therapy results from a positive finding.• Patients with CVT should preferably be treated with low molecular weight heparine (LMWH) instead of unfractionated heparine in the acute phase.• On an individual basis, endovascular recanalization in a neurointerventional center may be considered for patients who deteriorate under adequate anticoagulation.• Despite the overall low level of evidence, surgical decompression should be performed in patients with CVT, parenchymal lesions (congestive edema and/or hemorrhage) and impending incarceration to prevent death.• Following the acute phase, oral anticoagulation with direct oral anticoagulants instead of vitamin K antagonists should be given for 3 to 12 months to enhance recanalization and prevent recurrent CVT as well as extracerebral venous thrombosis.• Women with previous CVT in connection with the use of combined hormonal contraceptives or pregnancy shall refrain from continuing or restarting contraception with oestrogen-progestagen combinations due to an increased risk of recurrence if anticoagulation is no longer used.• Women with previous CVT and without contraindications should receive LMWH prophylaxis during pregnancy and for at least 6 weeks post partum.Although the level of evidence supporting these recommendations is mostly low, evidence from deep venous thrombosis as well as current clinical experience can justify the new recommendations.This article is an abridged translation of the German guideline, which is available online.

Prevalence of perioperative asymptomatic venous thromboses of the lower extremity in 30 consecutive patients undergoing transsphenoidal surgery for Cushing's disease

Cushing´s disease is a rare endocrinological disorder which is caused by an adrenocorticotropic hormone secreting pituitary adenoma. The condition is associated with an increased risk for venous thromboembolism. While there exist reports on symptomatic venous thromboses complicating Cushing's disease, the prevalence of incidental leg vein thromboses accompanying pituitary surgery for Cushing's disease is yet unknown. 30 consecutive patients (9 male; age 25-77 years) with histologically confirmed Cushing's disease underwent transsphenoidal adenomectomy between October 2018 and September 2019. All patients received perioperative pharmacological thromboprophylaxis. Whole leg compression ultrasound was performed within one week after surgery (median 2 days) to exclude leg vein thromboses (primary endpoint). Preoperative laboratory values including plasma cortisol and various coagulation parameters were evaluated as secondary outcome measures. A comparison was made between patients with and without thrombotic events (p value ≤ 0.05). A total of 2 out of 30 patients (6.7%; CI 0.8-24.1%) presented with asymptomatic perioperative deep vein thromboses of the lower legs. Thrombosis patients differed not significantly from their counterparts with respect to age, sex, and comorbidities, but preoperative morning plasma cortisol was significantly higher in patients with venous thromboses (421.0 ± 49.5 μg/l vs. 188.1 ± 78.2 μg/l; p = 0.01). Moreover, von Willebrand factor activity was markedly increased in one case (409.0%) compared to the mean value obtained from 28 patients without phlebothromboses (146.9 ± 60.7%; p < 0.01). Perioperative asymptomatic leg vein thrombosis can be found with the aid of compression ultrasound in a considerable proportion of patients undergoing transsphenoidal adenomectomy for Cushing's disease despite the administration of pharmacological thromboprophylaxis.

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.

Prophylaxis and management of venous thromboembolism during pregnancy and postpartum period

Introduction. Venous thromboembolism (VTE) is one of the lead causes for maternal mortality and morbidity during pregnancy in the majority of developed countries. The incidence rate of VTE per pregnancy-year increases during pregnancy and postpartum period about by 4-fold and at least 14-fold, respectively.

Aim: to analyze and summarize current view on risk factors of thrombotic events during gestation and to discuss recent guidelines for the management of venous thromboembolic complications during pregnancy and postpartum, by taking into account a balance between risks and benefits of using anticoagulants.

Materials and Methods. The literature search covering the last 10 years was carried out in the electronic scientific databases RSCI, PubMed/MEDLINE, and Embase. While formulating a search strategy for evidence-based information, the PICO method (P = Patient; I = Intervention; C = Comparison; O = Outcome) and the key terms “venous thromboembolism” and “pregnancy” were used.

Results. Risk factors were found to include a personal history of VTE, verified inherited or acquired thrombophilia, a family history of VTE and general medical conditions, such as immobilization, overweight, varicose veins, some hematological diseases and autoimmune disorders. VTE is considered being potentially preventable upon prophylactic administration of anticoagulants, but no high confidence randomized clinical trials comparing diverse strategies of thromboprophylaxis in pregnant women have been proposed so far. Because heparins do not cross the placenta, weight-adjusted therapeutic-dose low molecular weight heparins (LMWH) represent the anticoagulant treatment of choice for VTE during pregnancy. Once- and twice-daily dosing regimens are acceptable. However, no evidence suggesting benefits for measurement of factor Xa activities and consecutive LMWH dose adjustments to improve clinical outcomes are available. In case of uncomplicated pregnancy-related VTE, no routine administration of vitamin K antagonists, direct thrombin or factor Xa inhibitors, fondaparinux, or danaparoid is recommended. Lactating women may switch from applying LMWH to warfarin. Anticoagulation therapy should be continued for 6 weeks postpartum with total duration lasting at least for 3 months.

Conclusion. VTE is a challenging task in pregnant women expecting to apply a multi-faceted approach for its efficient solution by taking into account updated recommendations and personalized patient-oriented features.

What Do We Know about Thromboprophylaxis and Its Monitoring in Critically Ill Patients?

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, is an important complication in patients hospitalized in intensive care units (ICU). Thromboprophylaxis is mainly performed with Low Molecular Weight Heparin (LMWH) and, in some specific patients, with Unfractionated Heparin (UFH). These intensive units are an environment where individual patient variability is extreme and where traditional antithrombotic protocols are frequently ineffective. This was known for a long time, but the hospitalization of many patients with COVID-19 inflammatory storms suddenly highlighted this knowledge. It is therefore reasonable to propose variable antithrombotic prevention protocols based initially on a series of individual criteria (weight, BMI, and thrombotic risks). Secondly, they should be adjusted by the monitoring of anticoagulant activity, preferably by measuring the anti-Xa activity. However, we still face unresolved questions, such as once- or twice-daily LMWH injections, monitoring at the peak and/or trough, and poorly defined therapeutic targets. Equally surprisingly, we observed a lack of standardization of the anti-Xa activity kits.

Twice- or Once-Daily Dosing of Direct Oral Anticoagulants, a systematic review and meta-analysis

AIM

The direct oral anticoagulants (DOAC) have similar half-lives, but the dosing regimen varies between once daily (QD) or twice daily (BID). For some prescribers, the QD regimen improves compliance. Others prefer BID regimens to promote better stability of plasma concentrations, particularly in the event of missed doses. Limited level of evidence provides guidance about the best treatment strategy. The purpose of this study was to compare the treatment effect of QD vs. BID administration of DOACs in major orthopedic surgery (MOS), non-valvular atrial fibrillation (NVAF), venous thromboembolism (VTE), and acute coronary syndrome (ACS).

METHODS

We conducted a systematic review up to April 2020. We included phase II clinical trials comparing DOAC QD vs BID with same daily dose. We extracted data for the occurrence of major thrombosis (proximal deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemic stroke) and major hemorrhage (ISTH criteria and recommendations of the European Medicines Agency for surgical patients). Relative risks (RR) were combined using a fixed and random effects weighted meta-analysis.

RESULTS

Twelve randomized, controlled, phase II trials were included (10,716 patients), representing 24 dosing regimen comparisons of apixaban, darexaban, edoxaban, rivaroxaban, letaxaban, and dabigatran. There was no difference for major thrombotic event (RR_BID/QD = 1.06, 95%IC 0.86-1.30) nor for major bleeding (RR_BID/QD = 1.02, 95%IC 0.84-1.23) between the BID vs QD regimens, without heterogeneity (I² = 0%).

CONCLUSION

Our study does not support a global difference in term of efficacy and safety of the BID and QD regimens of DOAC in MOS, NVAF, VTE and ACS.

Once-daily vs. twice-daily dosing of enoxaparin for the management of venous thromboembolism: A systematic review and meta-analysis

The present study aimed to determine whether there is any difference in the efficacy and safety of once-daily vs. twice-daily enoxaparin when used for the initial treatment of venous thromboembolism (VTE). The PubMed, Embase, Cochrane Central Register of Controlled Trials, Science Direct and Google Scholar databases were searched for studies comparing once-daily and twice-daily enoxaparin for the initial treatment of VTE added from inception up to 1st October 2019. Studies utilizing any other low-molecular-weight heparin and using enoxaparin for VTE prophylaxis were excluded. A total of 6 studies were included in the systematic review and 5 in the meta-analysis. Only one study was a randomized controlled trial (RCT). Pooled analysis of 460 patients receiving once-daily enoxaparin and 464 patients receiving twice-daily enoxaparin indicated no significant difference between the two dosing regimens regarding VTE recurrence [odds ratio (OR)=1.48, 95%CI: 0.75-2.89, P=0.26; I²=0%]. No significant difference in major hemorrhagic complications was noted (OR=1.21, 95%CI: 0.52-2.81, P=0.66; I²=0%). Sub-group analysis based on study type and use of enoxaparin for bridging therapy did not change the overall results. In cancer patients, no statistically significant difference in the recurrence of VTE was obtained between once-daily and twice-daily enoxaparin, but the confidence intervals were wide with a tendency to favor twice-daily dosing (OR=2.28, 95%CI: 0.91-5.75, P=0.08; I²=0%). The overall quality of the studies was determined to be average. To conclude, while the present results suggested no significant difference in efficacy and safety of once-daily vs. twice-daily enoxaparin when used for the initial treatment of VTE, the quality of the evidence may not have been sufficiently high to support the conclusions with confidence. Further high-quality and adequately powered RCTs are required to corroborate the present results.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy

BACKGROUND

Venous thromboembolism (VTE) complicates ∼1.2 of every 1000 deliveries. Despite these low absolute risks, pregnancy-associated VTE is a leading cause of maternal morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and others in decisions about the prevention and management of pregnancy-associated VTE.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

The panel agreed on 31 recommendations related to the treatment of VTE and superficial vein thrombosis, diagnosis of VTE, and thrombosis prophylaxis.

CONCLUSIONS

There was a strong recommendation for low-molecular-weight heparin (LWMH) over unfractionated heparin for acute VTE. Most recommendations were conditional, including those for either twice-per-day or once-per-day LMWH dosing for the treatment of acute VTE and initial outpatient therapy over hospital admission with low-risk acute VTE, as well as against routine anti-factor Xa (FXa) monitoring to guide dosing with LMWH for VTE treatment. There was a strong recommendation (low certainty in evidence) for antepartum anticoagulant prophylaxis with a history of unprovoked or hormonally associated VTE and a conditional recommendation against antepartum anticoagulant prophylaxis with prior VTE associated with a resolved nonhormonal provoking risk factor.

Once-Daily Versus Twice-Daily Enoxaparin for the Treatment of Acute Venous Thromboembolism in Cancer Patients

BACKGROUND

No randomized controlled trials have investigated enoxaparin once versus twice daily for venous thromboembolism (VTE) treatment in cancer patients.

OBJECTIVE

To compare the safety and efficacy of enoxaparin 1 mg/kg twice daily versus enoxaparin 1.5 mg/kg/day for the treatment of acute VTE in cancer patients.

METHODS

This was a single-center, retrospective, observational cohort study. Adults with active cancer and an acute VTE were included. The primary outcome evaluated was the incidence of clinically relevant (major and nonmajor) bleeding (CRB) within 30 days of enoxaparin initiation. Secondary outcomes included the incidence of CRB, thrombosis, and death at 30, 90, and 180 days. The study protocol was approved by the institutional review board.

RESULTS

A total of 123 patients met inclusion criteria; 85 patients (69%) were treated with once-daily and 38 patients (31%) with twice-daily enoxaparin. CRB was numerically higher at 30 days in the twice-daily enoxaparin group compared with the once-daily group (5.3% vs 2.4%, P = 0.587). There was a nonsignificant higher incidence of CRB in the once-daily enoxaparin group compared with the twice-daily group at 90 days (8.3% vs 8%, P = 1.0) and 180 days (12.5% vs 7.1%, P = 1.0). The composite outcome of CRB, thrombosis, and death was higher at all time points with enoxaparin once daily.

CONCLUSIONS

Lack of statistical power in this study precludes definitive conclusions. Clinicians may consider twice-daily enoxaparin because of potentially fewer adverse events but may be limited by patient preference and/or financial constraints.

Initial anticoagulation in patients with pulmonary embolism: thrombolysis, unfractionated heparin, LMWH, fondaparinux, or DOACs?

The initial treatment of haemodynamically stable patients with pulmonary embolism (PE) has dramatically changed since the introduction of low molecular weight heparins (LMWHs). With the recent discovery of the direct oral anticoagulant drugs (DOACs), initial treatment of PE will be simplified even further. In several large clinical trials it has been demonstrated that DOACs are not inferior to standard therapy for the initial treatment of PE, and because of their practicability they are becoming the agents of first choice. However, many relative contraindications to DOACs were exclusion criteria in the clinical trials. Therefore, LMWHs will continue to play an important role in initial PE treatment and in some cases there still is a role for unfractionated heparin (UFH). In this review we will give an overview of the biophysical, pharmacokinetic and pharmacodynamic properties of anticoagulants currently available for the initial management of PE. In addition, we will provide a comprehensive overview of the indications for the use of UFH, LMWHs and DOACs in the initial management of PE from a pharmacokinetic/-dynamic point of view.

Warfarin initiation nomograms for venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is a common condition in hospital patients. Considerable controversy is ongoing regarding optimal initial warfarin dosing for patients with acute deep venous thrombosis (DVT) and pulmonary embolism (PE). Achieving a therapeutic international normalized ratio (INR) with warfarin as soon as possible is important because this minimizes the duration of parenteral medication necessary to attain immediate anticoagulation, and it potentially decreases the cost and inconvenience of treatment. Although a 5-mg loading-dose nomogram tends to prevent excessive anticoagulation, a 10-mg loading-dose nomogram may achieve a therapeutic INR more quickly. This is an update of a review first published in 2013.

OBJECTIVES

To evaluate the efficacy of a 10-mg warfarin nomogram compared with a 5-mg warfarin nomogram among patients with VTE.

SEARCH METHODS

For this update the Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched September 2015) and the Cochrane Register of Studies (CENTRAL (2015, Issue 8). Clinical trials databases were also searched. The review authors searched PubMed (last searched 11 June 2015) and LILACS (last searched 11 June 2015). In addition, the review authors contacted pharmaceutical companies.

SELECTION CRITERIA

Randomized controlled studies comparing warfarin initiation nomograms of 10 and 5 mg in patients with VTE.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The review authors contacted study authors for additional information.

MAIN RESULTS

Four trials involving 494 participants were included. Three studies involving 383 participants provided data on the proportion of participants who had achieved a therapeutic INR by day five. Significant benefit of a 10-mg warfarin nomogram was observed (risk ratio (RR) 1.27, 95% confidence interval (CI) 1.05 to 1.54; moderate quality evidence), although with substantial heterogeneity (I(2) = 90%). The review authors analyzed each study separately because it was not possible to perform a subgroup analysis by inpatient or outpatient status. One study showed significant benefit of a 10-mg warfarin nomogram for the proportion of outpatients with VTE who had achieved a therapeutic INR by day five (RR 1.78, 95% CI 1.41 to 2.25), with the number needed to treat for an additional beneficial outcome (NNTB = 3, 95% CI 2 to 4); another study showed significant benefit of a 5-mg warfarin nomogram in outpatients with VTE (RR 0.58, 95% CI 0.36 to 0.93) with NNTB = 5 (95% CI 3 to 28); a third study, consisting of both inpatients and outpatients, showed no difference (RR 1.08, 95% CI 0.65 to 1.80).No difference was observed in recurrent venous thromboembolism at 90 days when the warfarin nomogram of 10 mg was compared with the warfarin nomogram of 5 mg (RR 1.48, 95% CI 0.39 to 5.56; 3 studies, 362 participants, low quality evidence); no difference was observed in major bleeding at 14 to 90 days (RR 0.97, 95% CI 0.27 to 3.51; 4 studies, 494 participants, moderate quality evidence). No difference was observed in minor bleeding at 14 to 90 days (RR 0.52, 95% CI 0.15 to 1.83; 2 studies, 243 participants, very low quality evidence) or in length of hospital stay (mean difference (MD) -2.3 days, 95% CI -7.96 to 3.36; 1 study, 111 participants, low quality evidence).

AUTHORS' CONCLUSIONS

In patients with acute thromboembolism (DVT or PE) aged 18 years or older, considerable uncertainty surrounds the use of a 10-mg or a 5-mg loading dose for initiation of warfarin to achieve an INR of 2.0 to 3.0 on the fifth day of therapy. Heterogeneity among analyzed studies, mainly caused by differences in types of study participants and length of follow-up, limits certainty surrounding optimal warfarin initiation nomograms.

Guidance for the treatment and prevention of obstetric-associated venous thromboembolism

Venous thromboembolism (VTE), which may manifest as pulmonary embolism (PE) or deep vein thrombosis (DVT), is a serious and potentially fatal condition. Treatment and prevention of obstetric-related VTE is complicated by the need to consider fetal, as well as maternal, wellbeing when making management decisions. Although absolute VTE rates in this population are low, obstetric-associated VTE is an important cause of maternal morbidity and mortality. This manuscript, initiated by the Anticoagulation Forum, provides practical clinical guidance on the prevention and treatment of obstetric-associated VTE based on existing guidelines and consensus expert opinion based on available literature where guidelines are lacking.