Fixed dose subcutaneous low molecular weight heparins versus adjusted dose unfractionated heparin for the initial treatment of venous thromboembolism

How enoxaparin underdosing and sex contribute to achieving therapeutic anti-Xa levels

Introduction

Anti-Xa serves as a clinical surrogate for assessing the efficacy and bleeding risk in patients treated with enoxaparin for thromboembolic events. Evidence from the literature and empirical observations suggest that patients are underdosed in clinical practice to avoid bleeding complications. This study aimed to investigate such underdosing of enoxaparin and its potential impact on achieving therapeutic anti-Xa levels.

Methods

This multicentric, retrospective, observational study included patients with acute ischemic stroke due to atrial fibrillation. All patients received enoxaparin in the therapeutic setting with subsequent anti-Xa measurements. The one-sample, one-tailed Wilcoxon signed-rank test was used to identify a significant difference between the doses administered and the recommended daily dose. Logistic regression model analysis was performed to identify additional predictors affecting achievement of the therapeutic anti-Xa target range. Stepwise forward-backward selection with Akaike's information criterion as metric was applied to refine the logistic regression model.

Results

A total of 145 patients from the university hospitals of St. Pölten and Tulln in Lower Austria were included. The median daily enoxaparin dose administered was 1.23 mg/kg, resulting in an overall target range achievement rate of 66%. As compared to recommended therapeutic doses, significant underdosing of enoxaparin was evident in both participating centers (p < 0.001). The calculated threshold dose to achieve the therapeutic target range with a 90% probability was 1.5 mg/kg enoxaparin daily. Female sex was found to be a strong independent predictor of achieving a therapeutic target range (OR 9.44; 95% CI 3.40-30.05, p < 0.001).

Conclusion

Despite the underdosing observed in both centers, therapeutic anti-Xa levels were achieved with lower than recommended doses of enoxaparin, and women required even lower doses than men. These findings warrant further confirmation by prospective studies.

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.

Delayed filling of the superficial middle cerebral vein in acute large artery occlusion

Objective

This study aimed to determine whether baseline delayed filling of the superficial middle cerebral vein (SMCV) was an independent cause of stroke prognosis in patients with acute anterior large vessel occlusion (LVO).

Methods

Consecutive patients with acute LVO [middle cerebral artery M1 ± intracranial internal carotid artery (ICA)] between March 2019 and May 2020 were included. Delayed SMCV was defined as delayed filling of SMCV in the affected side compared with the normal side throughout the venous phase on four-dimensional computed tomographic angiography (4D-CTA) reconstructed from CT perfusion imaging. The modified Rankin scale (mRS) was used to evaluate the prognosis of these patients 3 months after stroke.

Results

Of 54 patients in total, 47 (87.0%) patients presented with baseline delayed SMCV, and 36 (76.6%) patients achieved SMCV reversal (ipsilateral delayed SMCV reversed to bilateral symmetrical SMCV) after reperfusion therapy. Successful reperfusion was independently associated with SMCV reversal [odds ratio (OR) = 69.328, 95% confidence interval (CI) = 2.818–175.342]. A significant association between baseline SMCV delay and a 3-month poor outcome (OR = 19.623, 95% CI = 1.567–245.727, p = 0.021) was observed using a multivariable regression analysis. Compared with patients with persistent delayed SMCV, patients with reversed SMCV did not show a significant difference in the risk of a 3-month poor outcome (OR = 1.177, 95% CI = 0.147–9.448).

Conclusions

In patients with acute LVO, baseline delayed SMCV was an independent cause of poor stroke prognosis, and SMCV reversal cannot reverse the 3-month stroke prognosis. Therefore, the evaluation of baseline SMCV filling status should be strengthened in clinical practice.

An Update on the Management of Acute High-Risk Pulmonary Embolism

Hemodynamic instability and right ventricular (RV) dysfunction are the key determinants of short-term prognosis in patients with acute pulmonary embolism (PE). High-risk PE encompasses a wide spectrum of clinical situations from sustained hypotension to cardiac arrest. Early recognition and treatment tailored to each individual are crucial. Systemic fibrinolysis is the first-line pulmonary reperfusion therapy to rapidly reverse RV overload and hemodynamic collapse, at the cost of a significant rate of bleeding. Catheter-directed pharmacological and mechanical techniques ensure swift recovery of echocardiographic parameters and may possess a better safety profile than systemic thrombolysis. Further clinical studies are mandatory to clarify which pulmonary reperfusion strategy may improve early clinical outcomes and fill existing gaps in the evidence.

Anticoagulation for the initial treatment of venous thromboembolism in people with cancer

BACKGROUND

Compared with people without cancer, people with cancer who receive anticoagulant treatment for venous thromboembolism (VTE) are more likely to develop recurrent VTE.

OBJECTIVES

To compare the efficacy and safety of three types of parenteral anticoagulants (i.e. fixed-dose low molecular weight heparin (LMWH), adjusted-dose unfractionated heparin (UFH), and fondaparinux) for the initial treatment of VTE in people with cancer.

SEARCH METHODS

We performed a comprehensive search in the following major databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (via Ovid) and Embase (via Ovid). We also handsearched conference proceedings, checked references of included studies, and searched for ongoing studies. This update of the systematic review is based on the findings of a literature search conducted on 14 August 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the benefits and harms of LMWH, UFH, and fondaparinux in people with cancer and objectively confirmed VTE.

DATA COLLECTION AND ANALYSIS

Using a standardised form, we extracted data - in duplicate - on study design, participants, interventions, outcomes of interest, and risk of bias. Outcomes of interest included all-cause mortality, symptomatic VTE, major bleeding, minor bleeding, postphlebitic syndrome, quality of life, and thrombocytopenia. We assessed the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

Of 11,484 identified citations, 3073 were unique citations and 15 RCTs fulfilled the eligibility criteria, none of which were identified in the latest search. These trials enrolled 1615 participants with cancer and VTE: 13 compared LMWH with UFH; one compared fondaparinux with UFH and LMWH; and one compared dalteparin with tinzaparin, two different types of low molecular weight heparin. The meta-analyses showed that LMWH may reduce mortality at three months compared to UFH (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.40 to 1.10; risk difference (RD) 57 fewer per 1000, 95% CI 101 fewer to 17 more; low certainty evidence) and may reduce VTE recurrence slightly (RR 0.69, 95% CI 0.27 to 1.76; RD 30 fewer per 1000, 95% CI 70 fewer to 73 more; low certainty evidence). There were no data available for bleeding outcomes, postphlebitic syndrome, quality of life, or thrombocytopenia. The study comparing fondaparinux with heparin (UFH or LMWH) found that fondaparinux may increase mortality at three months (RR 1.25, 95% CI 0.86 to 1.81; RD 43 more per 1000, 95% CI 24 fewer to 139 more; low certainty evidence), may result in little to no difference in recurrent VTE (RR 0.93, 95% CI 0.56 to 1.54; RD 8 fewer per 1000, 95% CI 52 fewer to 63 more; low certainty evidence), may result in little to no difference in major bleeding (RR 0.82, 95% CI 0.40 to 1.66; RD 12 fewer per 1000, 95% CI 40 fewer to 44 more; low certainty evidence), and probably increases minor bleeding (RR 1.53, 95% CI 0.88 to 2.66; RD 42 more per 1000, 95% CI 10 fewer to 132 more; moderate certainty evidence). There were no data available for postphlebitic syndrome, quality of life, or thrombocytopenia. The study comparing dalteparin with tinzaparin found that dalteparin may reduce mortality slightly (RR 0.86, 95% CI 0.43 to 1.73; RD 33 fewer per 1000, 95% CI 135 fewer to 173 more; low certainty evidence), may reduce recurrent VTE (RR 0.44, 95% CI 0.09 to 2.16; RD 47 fewer per 1000, 95% CI 77 fewer to 98 more; low certainty evidence), may increase major bleeding slightly (RR 2.19, 95% CI 0.20 to 23.42; RD 20 more per 1000, 95% CI 14 fewer to 380 more; low certainty evidence), and may reduce minor bleeding slightly (RR 0.82, 95% CI 0.30 to 2.21; RD 24 fewer per 1000, 95% CI 95 fewer to 164 more; low certainty evidence). There were no data available for postphlebitic syndrome, quality of life, or thrombocytopenia.

AUTHORS' CONCLUSIONS

Low molecular weight heparin (LMWH) is probably superior to UFH in the initial treatment of VTE in people with cancer. Additional trials focusing on patient-important outcomes will further inform the questions addressed in this review. The decision for a person with cancer to start LMWH therapy should balance the benefits and harms and consider the person's values and preferences.

Advances in the Prediction and Risk Assessment of Lung Cancer-Associated Venous Thromboembolism

According to the most recent data from the National Cancer Center, venous thromboembolism (VTE) has unsurprisingly become one of the most common complications in lung cancer. VTE not only interferes with the equilibrium of the clotting system but it also affects tumor progression and prognosis. For the identification of high-risk patients, many clinical risk assessment models have been developed and validated based on the risk factors found in previous studies. In this review, we will summarize advances in prediction and risk assessment of VTE, with a focus on early diagnosis and therapy, reduction of mortality, and the burden of medical costs in lung cancer patients.

Available Bleeding Scoring Systems Poorly Predict Major Bleeding in the Acute Phase of Pulmonary Embolism

We aimed to compare six available bleeding scores, in a real-life cohort, for prediction of major bleeding in the early phase of pulmonary embolism (PE). We recorded in-hospital characteristics of 2754 PE patients in a prospective observational multicenter cohort contributing 18,028 person-days follow-up. The VTE-BLEED (Venous Thrombo-Embolism Bleed), RIETE (Registro informatizado de la enfermedad tromboembólica en España; Computerized Registry of Patients with Venous Thromboembolism), ORBIT (Outcomes Registry for Better Informed Treatment), HEMORR₂HAGES (Hepatic or Renal Disease, Ethanol Abuse, Malignancy, Older Age, Reduced Platelet Count or Function, Re-Bleeding, Hypertension, Anemia, Genetic Factors, Excessive Fall Risk and Stroke), ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation), and HAS-BLED (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile International Normalized Ratio, Elderly, Drugs/Alcohol) scores were assessed at baseline. International Society on Thrombosis and Haemostasis (ISTH)-defined bleeding events were independently adjudicated. Accuracy of the overall original 3-level and newly defined optimal 2-level outcome of the scores were evaluated and compared. We observed 82 first early major bleedings (3.0% (95% CI, 2.4–3.7)). The predictive power of bleeding scores was poor (Harrel’s C-index from 0.57 to 0.69). The RIETE score had numerically higher model fit and discrimination capacity but without reaching statistical significance versus the ORBIT, HEMORR₂HAGES, and ATRIA scores. The VTE-BLEED and HAS-BLED scores had significantly lower C-index, integrated discrimination improvement, and net reclassification improvement compared to the others. The rate of observed early major bleeding in score-defined low-risk patients was high, between 15% and 34%. Current available scoring systems have insufficient accuracy to predict early major bleeding in patients with acute PE. The development of acute-PE-specific risk scores is needed to optimally target bleeding prevention strategies.

Current Recommendations for the Management of Cancer-Associated Venous Thromboembolism

Cancer-associated thrombosis (CAT) is a major cause of death in oncological patients. The mechanisms of thrombogenesis in cancer patients are not fully established, and it seems to be multifactorial in origin. Also, several risk factors for venous thromboembolism (VTE) are present in these patients such as tumor site, stage, histology of cancer, chemotherapy, surgery, and immobilization. Anticoagulant treatment in CAT is challenging because of high bleeding risk during treatment and recurrence of VTE. Current major guidelines recommend low molecular weight heparins (LMWHs) for early and long-term treatment of VTE in cancer patients. In the past years, direct oral anticoagulants (DOACs) are recommended as potential treatment option for VTE and have recently been proposed as a new option for treating CAT. This manuscript will give a short overview of risk factors involved in the development of CAT and a summary on the recent recommendations and guidelines for treatment of VTE in patients with malignancies, discussing also some special clinical situations (e.g. renal impairment, catheter-related thrombosis, and thrombocytopenia).

Cerebral venous thrombosis: a practical guide

All neurologists need to be able to recognise and treat cerebral venous thrombosis (CVT). It is difficult to diagnose, partly due to its relative rarity, its multiple and various clinical manifestations (different from 'conventional' stroke, and often mimicking other acute neurological conditions), and because it is often challenging to obtain and interpret optimal and timely brain imaging. Although CVT can result in death or permanent disability, it generally has a favourable prognosis if diagnosed and treated early. Neurologists involved in stroke care therefore also need to be aware of the treatments for CVT (with varying degrees of supporting evidence): the mainstay is prompt anticoagulation but patients who deteriorate despite treatment can be considered for endovascular procedures (endovascular thrombolysis or thrombectomy) or neurosurgery (decompressive craniotomy). This review summarises current knowledge on the risk factors, diagnosis, treatment and prognosis of CVT in adults, and highlights some areas for future research.

Application of the RCOG Risk Assessment Model for Evaluating Postpartum Venous Thromboembolism in Chinese Women: A Case-Control Study

BACKGROUND Since China has not yet constructed its own risk assessment model (RAM) for pregnancy-related venous thromboembolism (VTE), more and more hospitals use the RCOG RAM for VTE risk prediction. However, the RCOG RAM was established based on Western populations, and its applicability in China is still uncertain. Thus, we aimed to evaluate the validity of the RCOG RAM in predicting postpartum VTE in Chinese maternity. MATERIAL AND METHODS This retrospective case-control study was conducted at the International Peace Maternity and Child Health Hospital (IPMCHH) from June 2016 to June 2020. The VTE group consisted of 38 women with postpartum VTE. For each VTE patient, 4 women without VTE who gave birth on the same day were randomly selected as the control group (n=152). The receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the discrimination, accuracy, and validity of the RCOG RAM. Univariable analysis and multivariable logistic regression analysis were used to identify other related factors for postpartum VTE. RESULTS Compared with the low-risk group, the risk of VTE was 9.75-fold greater in the intermediate-risk group, and 90.00-fold greater in the high-risk group. The area under curve (AUC) of the model was 0.828 (95% CI: 0.762-0.894), with a score of 2 as its best cut-off value, which exactly matched the criterion recommended by the RCOG guidelines for pharmacological thromboprophylaxis. The calibration curves and DCA of the model also showed good accuracy. In addition to the factors included in the RCOG RAM, glucocorticoid therapy during pregnancy (adjusted OR=6.72, 95% CI: 1.56-28.91) and previous use of IUD (adjusted OR=7.11, 95% CI: 1.45-34.93) were associated with increased risk of postpartum VTE. CONCLUSIONS The RCOG RAM was found to be effective in predicting postpartum VTE, and has certain guiding significance for postpartum thromboprophylaxis in China.

Updates in Anticoagulation Therapy Monitoring

In the past six decades, heparin and warfarin were the primary anticoagulants prescribed for treatment and prophylaxis of venous thromboembolism worldwide. This has been accompanied by extensive clinical knowledge regarding dosing, monitoring, and reversal of these anticoagulants, and the resources required to do so have largely been readily available at small and large centers alike. However, with the advent of newer oral and parenteral anticoagulants such as low molecular weight heparins, factor Xa inhibitors, and direct thrombin inhibitors in recent years, new corresponding practice guidelines have also emerged. A notable shift in the need for monitoring and reversal agents has evolved as well. While this has perhaps streamlined the process for physicians and is often desirable for patients, it has also left a knowledge and resource gap in clinical scenarios for which urgent reversal and monitoring is necessary. An overview of the currently available anticoagulants with a focus on the guidelines and available tests for anticoagulant monitoring will be discussed in this article.

Real world data on clinical profile, management and outcomes of venous thromboembolism from a tertiary care centre in India

OBJECTIVES

Venous thromboembolism (VTE) is a major cause of mortality and morbidity worldwide. This study describes a real-world scenario of VTE presenting to a tertiary care hospital in India.

METHODS

All patients presenting with acute VTE or associated complications from January 2017 to January 2020 were included in the study.

RESULTS

A total of 330 patient admissions related to VTE were included over 3 years, of which 303 had an acute episode of VTE. The median age was 50 years (IQR 38-64); 30% of patients were younger than 40 years of age. Only 24% of patients had provoked VTE with recent surgery (56%) and malignancy (16%) being the commonest risk factors. VTE manifested as isolated DVT (56%), isolated pulmonary embolism (PE; 19.1%), combined DVT/PE (22.4%), and upper limb DVT (2.3%). Patients with PE (n = 126) were classified as low-risk (15%), intermediate-risk (55%) and high-risk (29%). Reperfusion therapy was performed for 15.7% of patients with intermediate-risk and 75.6% with high-risk PE. In-hospital mortality for the entire cohort was 8.9%; 35% for high-risk PE and 11% for intermediate-risk PE. On multivariate analysis, the presence of active malignancy (OR = 5.8; 95% CI: 1.1-30.8, p = 0.038) and high-risk PE (OR = 4.8; 95% CI: 1.6-14.9, p = 0.006) were found to be independent predictors of mortality.

CONCLUSION

Our data provides real-world perspectives on the demographic sand management of patients presenting with acute VTE in a referral hospital setting. We observed relatively high mortality for intermediate-risk PE, necessitating better subclassification of this group to identify candidates for more aggressive approaches.

Feasibility of anticoagulation using low molecular-weight heparin during catheter-directed thrombolysis for lower extremity deep venous thrombosis

Background

The optimal anticoagulant scheme during catheter-directed thrombolysis (CDT) for deep venous thrombosis (DVT) remains unknown. This study was performed to evaluate the feasibility of anticoagulation therapy using low molecular-weight heparin (LMWH) during CDT for DVT.

Methods

The clinical data of DVT patients who underwent CDT during the past six years was retrospectively collected and reviewed. Patients were divided into therapeutic-dose anticoagulation (TPDA) and sub therapeutic-dose anticoagulation (sub-TPDA) groups according to LMWH dosage.

Results

A total of 61 patients involving 61 limbs were comprised. Acute and subacute DVT were identified in 39 (63.9%) and 22 (36.1%) patients, respectively. Thrombosis involving the iliac vein was identified in 34 (55.7%) patients. Inferior vena cava filter placement was performed in 38 (62.3%) patients. Intraoperatively, adjunctive balloons, stents, and thrombectomy were provided for nine (14.8%), four (6.6%), and one (1.6%) patients, respectively. Twenty (32.8%) patients accepted TPDA therapy, while 41 (67.2%) patients were administrated with sub-TPDA therapy. Median urokinase infusion rate was 2.5 (0.83 to 5) × 10⁴ U/h. Median infusion duration time was 4 (2 to 14) days, and median urokinase dose infused was 2.4 (0.6 to 10.80) × 10⁶ U. During CDT, five (8.2%) cases of minor bleeding were observed, and blood transfusion was not required. No major bleeding, symptomatic pulmonary embolisms, or death occurred. Complete (> 90%) and partial thrombolysis (50 ~ 90%) were achieved in 56 (91.8%) patients. In comparison with sub-TPDA group, TPDA group exhibited no significant differences in baseline characteristics, clinical improvement, thrombolysis results, and complications.

Conclusions

Anticoagulation therapy using low molecular-weight heparin during CDT with low infusion rate for DVT is likely to be feasible and safe. Sub-therapeutic-dose anticoagulation and therapeutic-dose could be used for CDT with similar clinical outcome and bleeding complications.

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.

Recurrent massive pulmonary emboli in a critically ill patient with COVID-19

We report the haematological management of a critically ill patient with coronavirus disease 2019 (COVID-19), with recurrent massive pulmonary emboli. A previous healthy 56-year-old man presented to the emergency department with severe hypoxaemic respiratory failure due to suspected COVID-19. He required invasive mechanical ventilation and transfer to the intensive care unit for increasing ventilatory requirements and cardiovascular instability. A computed tomography (CT) pulmonary angiogram demonstrated large bilateral pulmonary emboli with right heart strain, for which he received intravenous systemic thrombolysis followed by therapeutic weight-adjusted anticoagulation with low molecular weight heparin (dalteparin). Two weeks later, following an acute respiratory deterioration, a repeat CT pulmonary angiogram demonstrated a new saddle embolus with right heart strain requiring another regime of intravenous systemic thrombolysis. This occurred despite anti-Xa-guided therapeutic anticoagulation. The dose of therapeutic dalteparin was increased incrementally to an eventual dose of 12,500 units twice daily. A low threshold for radiological imaging should be considered in all COVID-19 patients with acute cardiorespiratory deterioration. Multidisciplinary team discussions highlighted aspects of balancing the risks of bleeding from anticoagulation vs. risk of death from pulmonary embolism. This report highlights the need for further research into the underlying mechanisms and optimal management of thrombotic complications in COVID-19.

Fatal Retroperitoneal Hematoma in a Patient Receiving Enoxaparin for Bilateral Pulmonary Emboli

Venous thromboembolism occurs when a deep vein thrombosis travels to the lungs and forms a pulmonary embolism. Low-molecular-weight heparins are a mainstay in the treatment and prevention of venous thromboembolism and should be initiated promptly due to substantial morbidity and mortality. A rare side effect of low-molecular-weight heparins is major bleeding, which also carries a significant morbidity and mortality rate. Here, we present a case of a fatal retroperitoneal hematoma in a patient being treated with enoxaparin for bilateral pulmonary emboli.

When Pigs Fly: A Multidisciplinary Approach to Navigating a Critical Heparin Shortage

A recent outbreak of African swine fever (ASF) in China has claimed the lives of millions of pigs, and although this virus has no health impacts on humans, the disruption of the global pig population has far-reaching negative impacts on economic and pork-derived products, including the creation of the critical drug heparin. The active pharmaceutical ingredient in heparin is derived from pig intestines, and because of the ASF outbreak, the U.S. faces an imminent shortage of heparin. This drug shortage has the potential for profound implications, as heparin is used in a substantial and varied number of medical conditions. In response to notification of the heparin shortage crisis, our institution, Massachusetts General Hospital, activated its Hospital Incident Command System to streamline organization of major stakeholders and oversee operational and clinical activities required to mitigate the potential risks and optimize alternative effective strategies. This article describes the essential elements of our institution's emergency response plan, including detailed clinical algorithms developed by our experts for maximal heparin conservation and waste reduction by promoting safe and effective alternative strategies. Through this practice, we have also identified opportunities to change providers' prescribing and utilization behaviors for the better. As the ASF has not yet been contained and this crisis continues, the strategies and policies employed by our institution can provide a framework for other institutions to tackle this ongoing challenge and future drug shortage crises. IMPLICATIONS FOR PRACTICE: A detailed description of how one institution addressed the current heparin crisis, to support heparin conservation and waste reduction, is provided. The strategies used helped decrease heparin use by 80% in less than 2 months of establishing the task force. This accomplishment can be credited to the development of a task force and strategic plan in which experts and stakeholders were quickly identified, offered a part in the decision-making process, and frequently updated. Furthermore, the response system was dynamic, accessible, and one in which challenges were recognized and acted upon. The key to any crisis management is respect for one another and constant and open communication. Heparin is such a widespread drug that this shortage can potentially affect every patient population and provider. Understanding one's institutional needs and the effect of this crisis on those needs is one of the first steps when developing a strategic plan. Continually evaluating and adjusting that approach in response to the needs of the institution are critical to its success. Moreover, as it did for the authors' institution, a constant appraisal of the strategies can lead to opportunities for improvements in organization and practice that can be sustained well beyond the crisis.

SEOM clinical guideline of venous thromboembolism (VTE) and cancer (2019)

In 2011, the Spanish Society of Medical Oncology (SEOM) first published a clinical guideline of venous thromboembolism (VTE) and cancer. This guideline was updated in 2014, and since then, multiple studies and clinical trials have changed the landscape of the treatment and prophylaxis of VTE in cancer patients. To incorporate the most recent evidence, including data from direct oral anticoagulants (DOACs) randomized clinical trials, SEOM presents a new update of the guideline.

Diagnosis, Treatment and Follow Up of Acute Pulmonary Embolism: Consensus Practice from the PERT Consortium

Pulmonary embolism (PE) is a life-threatening condition and a leading cause of morbidity and mortality. There have been many advances in the field of PE in the last few years, requiring a careful assessment of their impact on patient care. However, variations in recommendations by different clinical guidelines, as well as lack of robust clinical trials, make clinical decisions challenging. The Pulmonary Embolism Response Team Consortium is an international association created to advance the diagnosis, treatment, and outcomes of patients with PE. In this consensus practice document, we provide a comprehensive review of the diagnosis, treatment, and follow-up of acute PE, including both clinical data and consensus opinion to provide guidance for clinicians caring for these patients.

Low-Molecular-Weight Heparin-Functionalized Chitosan-Chondroitin Sulfate Hydrogels for Controlled Release of TGF-β3 and in vitro Neocartilage Formation

Repair of hyaline cartilage remains a huge challenge in clinic because of the avascular and aneural characteristics and the paucity of endogenous repair cells. Recently, tissue engineering technique, possessing unique capacity of repairing large tissue defects, avoiding donor complications and two-stage invasive surgical procedures, has been developed a promising therapeutic strategy for cartilage injury. In this study, we incorporated low-molecular-weight heparin (LMWH) into carboxymethyl chitosan-oxidized chondroitin sulfate (CMC-OCS) hydrogel for loading transforming growth factor-β3 (TGF-β3) as matrix of peripheral blood mesenchymal stem cells (PB-MSCs) to construct tissue-engineered cartilage. Meanwhile, three control hydrogels with or without LMWH and/or TGF-β3 were also prepared. The gelling time, microstructures, mechanical properties, degradation rate, cytotoxicity, and the release of TGF-β3 of different hydrogels were investigated. In vitro experiments evaluated the tri-lineage differentiation potential of PB-MSCs, combined with the proliferation, distribution, viability, morphology, and chondrogenic differentiation. Compared with non-LMWH-hydrogels, LMWH-hydrogels (LMWH-CMC-OCS-TGF-β3) have shorter gelling time, higher mechanical strength, slower degradation rate and more stable and lasting release of TGF-β3. After two weeks of culture in vitro, expression of cartilage-specific genes collagen type-2 (COL-2) and aggrecan (AGC), and secretion of glycosaminoglycan (GAG), and COL-2 proteins in LMWH-CMC-OCS-TGF-β3 group were significantly higher than those in other groups. COL-2 immunofluorescence staining showed that the proportion of COL-2 positive cells and immunofluorescence intensity in LMWH-CMC-OCS-TGF-β3 hydrogel were significantly higher than those in other groups. The LMWH-CMC-OCS-TGF-β3 hydrogel can slowly release TGF-β3 in a long term, and meanwhile the hydrogel can provide a biocompatible microenvironment for the growth and chondrogenic differentiation of PB-MSCs. Thus, LMWH functionalized CMC-OCS hydrogels proposed in this work will be beneficial for constructing functional scaffolds for tissue-engineered cartilage.

Anticoagulation in chronic kidney disease: from guidelines to clinical practice

BACKGROUND

Chronic kidney disease (CKD) is a major global public health problem, being closely connected to cardiovascular disease. CKD involves an elevated thromboembolic risk and requires anticoagulation, but the high rates of hemorrhage render it quite challenging.

HYPOTHESIS

There are no consensus recommendations regarding anticoagulation in CKD. Due to the currently limited data, clinicians need practical clues for monitoring and optimizing the treatment.

METHODS

Based on the available data, this review outlines the benefit-risk ratio of all types of anticoagulants in each stage of CKD and provides practical recommendations for accurate dosage adjustment, reversal of antithrombotic effect, and monitoring of renal function on a regular basis.

RESULTS

Evidence from randomized controlled trials supports the efficient and safe use of warfarin and direct oral anticoagulants (DOACs) in mild and moderate CKD. On the contrary, the data are poor and controversial for advanced stages. DOACs are preferred in CKD stages 1 to 3. In patients with stage 4 CKD, the choice of warfarin vs DOACs will take into consideration the pharmacokinetics of the drugs and patient characteristics. Warfarin remains the first-line treatment in end-stage renal disease, although in this case the decision to use or not to use anticoagulation is strictly individualized. Anticoagulation with heparins is safe in nondialysis-dependent CKD, but remains a challenge in the hemodialysis patients.

CONCLUSIONS

Although there is a need for cardiorenal consensus regarding anticoagulation in CKD, adequate selection of the anticoagulant type and careful monitoring are some extremely useful indications for overcoming management challenges.

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.

Lifting the fog in intermediate-risk (submassive) PE: full dose, low dose, or no thrombolysis?

Acute pulmonary embolism (PE) is a disease frequently encountered in clinical practice. While the management of haemodynamically stable, low risk patients with acute PE is well established, managing intermediate disease often presents a therapeutic dilemma. In this review, we discuss the various therapeutic options available in this patient group. This includes thrombolysis, surgical embolectomy and catheter directed techniques. We have also explored the role of specialist PE response teams in the management of such patients. ​.

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.

Portal vein thrombosis after cesarean section in a patient on prolonged bed rest due to threatened preterm labor

Portal vein thrombosis is a rare but life-threatening complication during pregnancy and postpartum period. Color Doppler ultrasound is useful for prompt diagnosis. Although the risk of complications should be considered, successful pregnancy with comorbid portal vein thrombosis is possible with appropriate anticoagulation therapy and close monitoring.

Diagnosis and management of cerebral venous thrombosis

Cerebral venous thrombosis (CVT) is rare and accounts for 0.5% of all strokes. Its clinical presentation is variable and diagnosis requires a high index of clinical suspicion in conjunction with neuroradiological diagnostic support. Treatment options are limited and are mostly based on consensus. Therefore, familiarity with international guidelines is important. Outcome is often good and most patients make a full recovery, although a small proportion suffers death or disability. Here, we describe the clinical features, risk factors, acute imaging features, management and complications of CVT.

Anticoagulation for the initial treatment of venous thromboembolism in people with cancer

BACKGROUND

Compared with people without cancer, people with cancer who receive anticoagulant treatment for venous thromboembolism (VTE) are more likely to develop recurrent VTE.

OBJECTIVES

To compare the efficacy and safety of three types of parenteral anticoagulants (i.e. fixed-dose low molecular weight heparin (LMWH), adjusted-dose unfractionated heparin (UFH), and fondaparinux) for the initial treatment of VTE in people with cancer.

SEARCH METHODS

A comprehensive search included a major electronic search of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) (2018, Issue 1), MEDLINE (via Ovid) and Embase (via Ovid); handsearching of conference proceedings; checking of references of included studies; use of the 'related citation' feature in PubMed; and a search for ongoing studies. This update of the systematic review was based on the findings of a literature search conducted on 14 January 2018.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the benefits and harms of LMWH, UFH, and fondaparinux in people with cancer and objectively confirmed VTE.

DATA COLLECTION AND ANALYSIS

Using a standardized form, we extracted data in duplicate on study design, participants, interventions outcomes of interest, and risk of bias. Outcomes of interested included all-cause mortality, symptomatic VTE, major bleeding, minor bleeding, postphlebitic syndrome, quality of life, and thrombocytopenia. We assessed the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

Of 15440 identified citations, 7387 unique citations, 15 RCTs fulfilled the eligibility criteria. These trials enrolled 1615 participants with cancer and VTE: 13 compared LMWH with UFH enrolling 1025 participants, one compared fondaparinux with UFH and LMWH enrolling 477 participants, and one compared dalteparin with tinzaparin enrolling 113 participants. The meta-analysis of mortality at three months included 418 participants from five studies and that of recurrent VTE included 422 participants from 3 studies. The findings showed that LMWH likely decreases mortality at three months compared to UFH (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.40 to 1.10; risk difference (RD) 57 fewer per 1000, 95% CI 101 fewer to 17 more; moderate certainty evidence), but did not rule out a clinically significant increase or decrease in VTE recurrence (RR 0.69, 95% CI 0.27 to 1.76; RD 30 fewer per 1000, 95% CI 70 fewer to 73 more; moderate certainty evidence).The study comparing fondaparinux with heparin (UFH or LMWH) did not exclude a beneficial or detrimental effect of fondaparinux on mortality at three months (RR 1.25, 95% CI 0.86 to 1.81; RD 43 more per 1000, 95% CI 24 fewer to 139 more; moderate certainty evidence), recurrent VTE (RR 0.93, 95% CI 0.56 to 1.54; RD 8 fewer per 1000, 95% CI 52 fewer to 63 more; moderate certainty evidence), major bleeding (RR 0.82, 95% CI 0.40 to 1.66; RD 12 fewer per 1000, 95% CI 40 fewer to 44 more; moderate certainty evidence), or minor bleeding (RR 1.53, 95% CI 0.88 to 2.66; RD 42 more per 1000, 95% CI 10 fewer to 132 more; moderate certainty evidence)The study comparing dalteparin with tinzaparin did not exclude a beneficial or detrimental effect of dalteparin on mortality (RR 0.86, 95% CI 0.43 to 1.73; RD 33 fewer per 1000, 95% CI 135 fewer to 173 more; low certainty evidence), recurrent VTE (RR 0.44, 95% CI 0.09 to 2.16; RD 47 fewer per 1000, 95% CI 77 fewer to 98 more; low certainty evidence), major bleeding (RR 2.19, 95% CI 0.20 to 23.42; RD 20 more per 1000, 95% CI 14 fewer to 380 more; low certainty evidence), or minor bleeding (RR 0.82, 95% CI 0.30 to 2.21; RD 24 fewer per 1000, 95% CI 95 fewer to 164 more; low certainty evidence).

AUTHORS' CONCLUSIONS

LMWH is possibly superior to UFH in the initial treatment of VTE in people with cancer. Additional trials focusing on patient-important outcomes will further inform the questions addressed in this review. The decision for a person with cancer to start LMWH therapy should balance the benefits and harms and consider the person's values and preferences.

Home versus in-patient treatment for deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) occurs when a blood clot blocks blood flow through a vein, which can occur after surgery, after trauma, or when a person has been immobile for a long time. Clots can dislodge and block blood flow to the lungs (pulmonary embolism (PE)), causing death. DVT and PE are known by the term venous thromboembolism (VTE). Heparin (in the form of unfractionated heparin (UFH)) is a blood-thinning drug used during the first three to five days of DVT treatment. Low molecular weight heparins (LMWHs) allow people with DVT to receive their initial treatment at home instead of in hospital. This is an update of a review first published in 2001 and updated in 2007.

OBJECTIVES

To compare the incidence and complications of venous thromboembolism (VTE) in patients treated at home versus patients treated with standard in-patient hospital regimens. Secondary objectives included assessment of patient satisfaction and cost-effectiveness of treatment.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register (last searched 16 March 2017), the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2), and trials registries. We also checked the reference lists of relevant publications.

SELECTION CRITERIA

Randomised controlled trials (RCTs) examining home versus hospital treatment for DVT, in which DVT was clinically confirmed and was treated with LMWHs or UFH.

DATA COLLECTION AND ANALYSIS

One review author selected material for inclusion, and another reviewed the selection of trials. Two review authors independently extracted data and assessed included studies for risk of bias. Primary outcomes included combined VTE events (PE and recurrent DVT), gangrene, heparin complications, and death. Secondary outcomes were patient satisfaction and cost implications. We performed meta-analysis using fixed-effect models with risk ratios (RRs) and 95% confidence intervals (CIs) for dichotomous data.

MAIN RESULTS

We included in this review seven RCTs involving 1839 randomised participants with comparable treatment arms. All seven had fundamental problems including high exclusion rates, partial hospital treatment of many in the home treatment arms, and comparison of UFH in hospital versus LMWH at home. These trials showed that patients treated at home with LMWH were less likely to have recurrence of VTE events than those given hospital treatment with UFH or LMWH (fixed-effect risk ratio (RR) 0.58, 95% confidence interval (CI) 0.39 to 0.86; 6 studies; 1708 participants; P = 0.007; low-quality evidence). No clear difference was seen between groups for major bleeding (RR 0.67, 95% CI 0.33 to 1.36; 6 studies; 1708 participants; P = 0.27; low-quality evidence), minor bleeding (RR 1.29, 95% CI 0.94 to 1.78; 6 studies; 1708 participants; P = 0.11; low-quality evidence), or mortality (RR 0.69, 95% CI 0.44 to 1.09; 6 studies; 1708 participants; P = 0.11; low-quality evidence). The included studies reported no cases of venous gangrene. We could not combine patient satisfaction and quality of life outcomes in meta-analysis owing to heterogeneity of reporting, but two of three studies found evidence that home treatment led to greater improvement in quality of life compared with in-patient treatment at some point during follow-up, and the third study reported that a large number of participants chose to switch from in-patient care to home-based care for social and personal reasons, suggesting it is the patient's preferred option (very low-quality evidence). None of the studies included in this review carried out a full cost-effectiveness analysis. However, a small randomised economic evaluation of the two alternative treatment settings involving 131 participants found that direct costs were higher for those in the in-patient group. These findings were supported by three other studies that reported on their costs (very low-quality evidence).Quality of evidence for data from meta-analyses was low to very low. This was due to risk of bias, as many of the included studies used unclear randomisation techniques, and blinding was a concern for many. Also, indirectness was a concern, as most studies included a large number of participants randomised to the home (LMWH) treatment group who were treated in hospital for some or all of the treatment period. A further issue for some outcomes was heterogeneity that was evident in measurement and reporting of outcomes.

AUTHORS' CONCLUSIONS

Low-quality evidence suggests that patients treated at home with LMWH are less likely to have recurrence of VTE than those treated in hospital. However, data show no clear differences in major or minor bleeding, nor in mortality (low-quality evidence), indicating that home treatment is no worse than in-patient treatment for these outcomes. Because most healthcare systems are moving towards more LMWH usage in the home setting it is unlikely that additional large trials will be undertaken to compare these treatments. Therefore, home treatment is likely to become the norm, and further research will be directed towards resolving practical issues by devising local guidelines that include clinical prediction rules, developing biomarkers and imaging that can be used to tailor therapy to disease severity, and providing training for community healthcare workers who administer treatment and monitor treatment progress.

Wikipedia as a gateway to biomedical research: The relative distribution and use of citations in the English Wikipedia

Wikipedia is a gateway to knowledge. However, the extent to which this gateway ends at Wikipedia or continues via supporting citations is unknown. Wikipedia's gateway functionality has implications for information design and education, notably in medicine. This study aims to establish benchmarks for the relative distribution and referral (click) rate of citations-as indicated by presence of a Digital Object Identifier (DOI)-from Wikipedia, with a focus on medical citations. DOIs referred from the English Wikipedia in August 2016 were obtained from Crossref.org. Next, based on a DOI's presence on a WikiProject Medicine page, all DOIs in Wikipedia were categorized as medical (WP:MED) or non-medical (non-WP:MED). Using this categorization, referred DOIs were classified as WP:MED, non-WP:MED, or BOTH, meaning the DOI may have been referred from either category. Data were analyzed using descriptive and inferential statistics. Out of 5.2 million Wikipedia pages, 4.42% (n = 229,857) included at least one DOI. 68,870 were identified as WP:MED, with 22.14% (n = 15,250) featuring one or more DOIs. WP:MED pages featured on average 8.88 DOI citations per page, whereas non-WP:MED pages had on average 4.28 DOI citations. For DOIs only on WP:MED pages, a DOI was referred every 2,283 pageviews and for non-WP:MED pages every 2,467 pageviews. DOIs from BOTH pages accounted for 12% (n = 58,475). The referral of DOI citations found in BOTH could not be assigned to WP:MED or non-WP:MED, as the page from which the referral was made was not provided with the data. While these results cannot provide evidence of greater citation referral from WP:MED than non-WP:MED, they do provide benchmarks to assess strategies for changing referral patterns. These changes might include editors adopting new methods for designing and presenting citations or the introduction of teaching strategies that address the value of consulting citations as a tool for extending learning.