Subcutaneous enoxaparin once or twice daily compared with intravenous unfractionated heparin for treatment of venous thromboembolic disease

To Compare the Effectiveness of Low-Molecular-Weight Heparin and Unfractionated Heparin in Reducing Lower Limb Girth in Deep Vein Thrombosis

INTRODUCTION

Treating deep vein thrombosis (DVT) using a once-daily dose of enoxaparin offers greater convenience and the possibility of home-based care for certain patients, as opposed to a continuous infusion of unfractionated heparin (UFH). The study aimed to determine the most cost-effective thromboprophylaxis between low-molecular-weight heparin (LMWH) and UFH for hospitalized patients.

MATERIALS AND METHODS

After obtaining clearance from the institutional ethical committee, the study was conducted in the Department of General Surgery, Sri Devaraj Urs Medical College, over a period of six months. Informed consent was obtained from all 46 patients included in this study. The participants were divided into two groups: group A received LMWH and group B received UFH.

RESULTS

The mean age in group A was 59.8 + 10.6 years and in group B was 54.9 + 12.3 years. There was no significant difference in the girth of the lower limb between the groups during the follow-up period (p > 0.05). In group A, there was a highly significant reduction in lower limb girth from day one to day five (p < 0.0001), day five to day 10 (p < 0.0001), and day one to day 10 (p < 0.0001). In group B, there was no significant reduction from day one to day five (p = 0.06), but there was a significant reduction from day five to day 10 (p = 0.001) and day one to day 10 (p = 0.001).

CONCLUSION

Treatment with LMWH as an anticoagulant significantly reduced the lower extremity girth and thrombus thickness in cases of DVT when compared to UFH.

Update on Anticoagulation Strategies in Patients with ECMO-A Narrative Review

The use of extracorporeal membrane oxygenation (ECMO) has recently increased exponentially. ECMO has become the preferred mode of organ support in refractory respiratory or circulatory failure. The fragile balance of haemostasis physiology is massively altered by the patient's critical condition and specifically the aetiology of the underlying disease. Furthermore, an application of ECMO conveys another disturbance of haemostasis due to blood-circuit interaction and the presence of an oxygenator. The purpose of this review is to summarise current knowledge on the anticoagulation management in patients undergoing ECMO therapy. The unfractionated heparin modality with monitoring of activated partial thromboplastin tests is considered to be a gold standard for anticoagulation in this specific subgroup of intensive care patients. However, alternative modalities with other agents are comprehensively discussed. Furthermore, other ways of monitoring can represent the actual state of coagulation in a more complex fashion, such as thromboelastometric/graphic methods, and might become more frequent. In conclusion, the coagulation system of patients with ECMO is altered by multiple variables, and there is a significant lack of evidence in this area. Therefore, a highly individualised approach is the best solution today.

Once-daily Compared With Twice-daily Enoxaparin Maintenance Therapy Appears Safe and Efficacious in Pediatric Venous Thromboembolism

INTRODUCTION

Once-daily enoxaparin (ODE), considered standard of care for venous thromboembolism (VTE) treatment in adults, has been infrequently assessed in children. To contribute available data to a limited field, we reviewed our center's experience with ODE in treating pediatric VTE compared with twice-daily enoxaparin (TDE).

MATERIALS AND METHODS

A retrospective analysis of children and adolescents 18 years of age or below diagnosed with VTE and treated at our institution with ODE or TDE maintenance therapy between April 2015 and December 2020 was performed. Patient demographics, clinical and laboratory data pertaining to VTE diagnosis, and management were gathered from electronic medical records and compared between the 2 cohorts.

RESULTS

Seventy-one children met the eligibility criteria. All patients were initially treated with TDE for 2 weeks before transitioning to ODE maintenance therapy (n=39; 55%) or continuing with TDE dosing (n=32; 45%).Extremity VTE was more common in ODE ( P =0.051) versus pulmonary/intracardiac sites in TDE ( P =0.002) when compared with other sites. Median enoxaparin dosing was 1.5 and 1.1 mg/kg/dose in ODE and TDE cohorts, respectively. Bleeding episodes were rare without any difference between the cohorts. Two patients (6%) were lost to follow up in TDE cohort. All evaluable patients in both cohorts had either complete/partial response (ODE n=35 [90%]; TDE n=24 [75%] or stable thrombus ODE n=4 [10%]; TDE n=6 [19%]).

CONCLUSIONS

Our results indicate that ODE, used after the initial TDE treatment period, is as safe and efficacious as TDE maintenance for the treatment of pediatric VTE. The difference in VTE sites may have contributed to the equal efficacy of both the cohorts. Future prospective studies in pediatric VTE are needed to validate these results.

The rationale, design, and methods of a trial to evaluate the efficacy and safety of oxygen therapy in patients with intermediate-risk acute pulmonary embolism

BACKGROUND

In patients with intermediate-risk pulmonary embolism (PE), reversal of hypoxic vasoconstriction could constitute a target for treatment that protects the right ventricular (RV) function until endogenous fibrinolysis occurs. The Air vs oxygen for Intermediate-Risk pulmonary embolism (AIR) trial aims to assess the effect of oxygen therapy in patients with intermediate-risk acute PE who do not have hypoxemia at baseline.

METHODS AND ANALYSES

AIR is a prospective, multicenter, randomized, open-label, parallel-group, proof-of-concept trial. A total of 90 patients hospitalized with intermediate-risk PE and an oxygen saturation of 90% or higher at baseline will be randomized in a 1:1 fashion to receive supplemental oxygen or ambient air. The primary outcome is a RV/LV diameter ratio equal or less than 1.0 on echocardiography measured 48 hours after the start of treatment. Secondary efficacy outcomes are the numerical change in the ratio of the RV to the LV diameter measured 48 hours and 7 days after the start of treatment, with respect to the baseline ratio measured at randomization. Clinical adverse events will be also collected.

RESULTS

Enrollment started in July 2019 and is expected to proceed until 2022. Median age of the first 50 patients was 74 years (interquartile range, 61-81), and 50% were female.

CONCLUSIONS

This multicenter trial will provide information about the value of supplemental oxygen in patients with intermediate-risk acute PE who do not have hypoxemia at baseline. The results will contribute to research that may assist patients with intermediate-risk PE in the future.

Reduced anticoagulation targets in extracorporeal life support (RATE): study protocol for a randomized controlled trial

BACKGROUND

Although life-saving in selected patients, ECMO treatment still has high mortality which for a large part is due to treatment-related complications. A feared complication is ischemic stroke for which heparin is routinely administered for which the dosage is usually guided by activated partial thromboplastin time (aPTT). However, there is no relation between aPTT and the rare occurrence of ischemic stroke (1.2%), but there is a relation with the much more frequent occurrence of bleeding complications (55%) and blood transfusion. Both are strongly related to outcome.

METHODS

We will conduct a three-arm non-inferiority randomized controlled trial, in adult patients treated with ECMO. Participants will be randomized between heparin administration with a target of 2-2.5 times baseline aPTT, 1.5-2 times baseline aPTT, or low molecular weight heparin guided by weight and renal function. Apart from anticoagulation targets, treatment will be according to standard care. The primary outcome parameter is a combined endpoint consisting of major bleeding including hemorrhagic stroke, severe thromboembolic complications including ischemic stroke, and mortality at 6 months.

DISCUSSION

We hypothesize that with lower anticoagulation targets or anticoagulation with LMWH during ECMO therapy, patients will have fewer hemorrhagic complications without an increase in thromboembolic complication or a negative effect on their outcome. If our hypothesis is confirmed, this study could lead to a change in anticoagulation protocols and a better outcome for patients treated with ECMO.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04536272 . Registered on 2 September 2020. Netherlands Trial Register NL7969.

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.

Optimal enoxaparin dosing strategies for venous thromboembolism prophylaxis and treatment of high body weight patients

OBJECTIVE

Obesity is a risk factor for developing venous thromboembolism (VTE). Optimal dosage of enoxaparin has not been established in the obese population. We aimed to study clinical outcomes and complications with enoxaparin in obese patients.

METHODS

A retrospective, single centre observational study of obese patients treated with enoxaparin for VTE (n = 47) using a body mass index (BMI)-stratified dosing, thromboprophylaxis (n = 46), and non-obese controls (n = 20) was performed. Anti-Xa was used to measure enoxaparin efficacy.

RESULTS

Patients with a median BMI of 36.3 kg/m2 (range 30-52.7) with a median weight of 136 kg (range 68-240) received therapeutic enoxaparin at median 120 mg BID (range 60-200). A median targeted anti-Xa level of 0.79 (95% CI 0.72-1.03) IU/mL was achieved in 58% of patients. Dose reduction, or increase was needed in 25%, and 16% patients respectively. Mild or major haemorrhage, or VTE occurred in 10%, 2% and 2% patients respectively. Patients with a median weight of 160 kg (range 130-245) received thromboprophylaxis with 40 mg BID enoxaparin. Targeted median anti-Xa of 0.22 IU/mL (95% CI 0.19-0.24) was achieved in 59% patients. Mild haemorrhage was seen in 2%, while none developed major haemorrhage or VTE. Control patients who received enoxaparin 40 mg daily did not develop VTE; 5% had minor bleeding events.

CONCLUSIONS

BMI-stratified therapeutic enoxaparin dosing regimen is safe and effective therapy in obese patients. Fixed dosing without monitoring may not be appropriate. Thromboprophylaxis with 40 mg BID in obese patients was efficacious in preventing VTE without excess bleeding compared to control patients.

Cost-effectiveness analysis for the parenteral anticoagulants in Jordan

Objectives

Pharmacoeconomic dimensions linking clinical effectiveness of parenteral anticoagulants for management of acute venous thromboembolism (VTE) and cost of treatment are needed to support choices by healthcare providers. The objective of the study was to conduct a cost-effectiveness analysis for 5-day treatment with parenteral anticoagulants in Jordan.

Methods

Cost-effectiveness analysis was conducted based on decision analysis tree model. The perspective was the payer, considering direct medical costs. Probabilities of failure of treatment and major bleeding were derived from published clinical studies. Costs were estimated based on 2019 prices in Jordan.

Key findings

The average cost of VTE hospitalization and major bleeding management in Jordan were 2324.00 US$ and 3347.40 US$, respectively. Bemiparin was associated with the highest clinical efficacy and lowest probability of major bleeding. Nadroparin had the lowest clinical efficacy, while tinzaparin was found to have the highest risk of major bleeding. Bemiparin had the lowest average cost-effectiveness ratio (101.63 US$/success) and nadroparin had the highest cost-effectiveness ratio (295.56 US$/success). Throughout the sensitivity analysis calculations, bemiparin and nadroparin had the lowest and highest cost of treatment, respectively.

Conclusions

The cost of parenteral anticoagulant drugs, the same as many other drugs, does not always correlate with cost of VTE treatment. Other direct medical costs (e.g. treatment failure and management of bleeding) have a high contribution to the total cost calculation. Pharmacoeconomically, bemiparin is the dominant cost-effective parenteral anticoagulant in Jordan, while nadroparin is the dominated one.

Treatment-Dose LMWH versus Prophylactic/Intermediate Dose Heparins in High-Risk COVID-19 Inpatients: Rationale and Design of the HEP-COVID Trial

Coronavirus disease-2019 (COVID-19) has been associated with significant risk of venous thromboembolism (VTE), arterial thromboembolism (ATE), and mortality particularly among hospitalized patients with critical illness and elevated D-dimer (Dd) levels. Conflicting data have yet to elucidate optimal thromboprophylaxis dosing. HEP-COVID (NCT04401293) is a phase 3, multicenter, pragmatic, prospective, randomized, pseudo-blinded, active control trial to evaluate efficacy and safety of therapeutic-dose low-molecular-weight heparin (LMWH) versus prophylactic-/intermediate-dose LMWH or unfractionated heparin (UFH) for prevention of a primary efficacy composite outcome of VTE, ATE, and all-cause mortality 30 ± 2 days post-enrollment. Eligible patients have COVID-19 diagnosis by nasal swab or serologic testing, requirement for supplemental oxygen per investigator judgment, and Dd >4 × upper limit of normal (ULN) or sepsis-induced coagulopathy score ≥4. Subjects are randomized to enoxaparin 1 mg/kg subcutaneous (SQ)/two times a day (BID) (creatinine clearance [CrCl] ≥ 30 mL/min) or 0.5 mg/kg (CrCl 15-30 mL/min) versus local institutional prophylactic regimens including (1) UFH up to 22,500 IU (international unit) daily (divided BID or three times a day), (2) enoxaparin 30 and 40 mg SQ QD (once daily) or BID, or (3) dalteparin 2,500 IU or 5,000 IU QD. The principal safety outcome is major bleeding. Events are adjudicated locally. Based on expected 40% relative risk reduction with treatment-dose compared with prophylactic-dose prophylaxis, 308 subjects will be enrolled (assuming 20% drop-out) to achieve 80% power. Distinguishing design features include an enriched population for the composite endpoint anchored on Dd >4 × ULN, stratification by intensive care unit (ICU) versus non-ICU, and the ability to capture asymptomatic proximal deep venous thrombosis via screening ultrasonography prior to discharge.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer.

CONCLUSIONS

Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

Clinical controversies in the treatment of cancer-associated venous thromboembolism

Cancer-associated venous thromboembolism (VTE) is a common complication of malignancy. Patients with cancer exhibit risk factors for both recurrent VTE and major or minor bleeding. Direct oral anticoagulants (DOACs) are an attractive treatment option; however, there is a lack of consensus among national guidelines for choice between DOACs and LMWH, agent selection, dosing strategy, and duration of anticoagulation. Characteristics of the thrombotic event, the malignancy, the patient, and the anticoagulant must be considered. A systematic search of online databases was performed to identify literature on the management of cancer-associated VTE. Multiple controversies remain surrounding the optimal treatment of cancer-associated VTE.

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.

Low molecular weight heparin versus unfractioned heparin for anticoagulation during perioperative extracorporeal membrane oxygenation: A single center experience in 102 lung transplant patients

Extracorporeal membrane oxygenation (ECMO) is gaining importance in the perioperative management of lung transplant patients. To date, the ideal substance for anticoagulation of ECMO patients is still a matter of debate. In this study, we describe our experience with the use of low molecular weight heparin (LMWH) in comparison with unfractioned heparin (UFH) in lung transplant patients undergoing perioperative ECMO support. We retrospectively analyzed data from all lung transplant patients who underwent perioperative ECMO support at our institution between 2013 and 2017. Bleeding events served as primary outcome parameter. Secondary outcome parameters consisted of thromboembolic events. 102 patients were included in this study, of which 22 (21.6%) received UFH for anticoagulation, and 80 (78.4%) received LMWH. There was no difference between the two groups in regard to serious bleeding events (22.7% in the UFH group vs 12.5% in the LMWH group, P = .31). However, the proportion of patients experiencing thromboembolic events was significantly higher in the UFH group than in the LMWH group (50% vs 20%, P = .01). After adjusting for baseline differences between the two groups, we still observed a difference with respect to thromboembolic events. These data remain to be validated in future prospective, randomized trials.

The Crashing Obese Patient

Emergency physicians (EP) frequently resuscitate and manage critically ill patients. Resuscitation of the crashing obese patient presents a unique challenge for even the most skilled physician. Changes in anatomy, metabolic demand, cardiopulmonary reserve, ventilation, circulation, and pharmacokinetics require special consideration. This article focuses on critical components in the resuscitation of the crashing obese patient in the emergency department, namely intubation, mechanical ventilation, circulatory resuscitation, and pharmacotherapy. To minimize morbidity and mortality, it is imperative that the EP be familiar with the pearls and pitfalls discussed within this article.

Prophylactic anti-coagulation after severe burn injury in critical care settings

BACKGROUND

Severely burnt patients are at an increased risk of thromboembolic complications, hence sufficient prophylactic anticoagulation is of paramount importance. Local guidelines at the Burns Centre in the Queen Elizabeth Hospital, Birmingham therefore advise increasing the standard dose of low molecular weight heparin in these patients. An audit was carried out to assess the current practice in burns patients to ensure adequate anticoagulation and adherence to guidelines.

MATERIALS AND METHODS

Retrospective data was collected on all burns patients in the Burns Centre over a two-year period. The main objectives were to assess:anticoagulation regimes prescribed to severe burns patientsmonitoring of Anti-Factor Xa levelsadjustment of dosing based on the resultsThe locally produced trust guidelines were used as the comparator.

RESULTS

All burns patients were prescribed anticoagulation, but often the dose was not increased as suggested in the guidelines. Although most of the severely burnt patients were prescribed adjusted higher doses of anti-coagulation, only 60% of these patients were monitored with Anti-Factor Xa assays. Of these assays, 66% showed sub-prophylactic levels. The majority of results led to the adjustment of the dose of anticoagulant. However, often dose changes were made late.

DISCUSSION AND CONCLUSIONS

The audit confirmed the need for increased doses of prophylactic anticoagulation in severe burns. The better adherence to the guidelines can be achieved by additional training and implementation of decision support via electronic prescribing system.

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.

Anticoagulation at the extremes of body weight: choices and dosing

INTRODUCTION

The landscape of therapeutic anticoagulation has changed dramatically over the past decade, with availability of direct oral anticoagulants (DOACs), which inhibit factor Xa or thrombin. However, the optimal anticoagulant agent and dosing strategy for patients at both extremes of body weight has not been established for any anticoagulant, including DOACs, vitamin K antagonists (VKA), and the various heparin options. Areas covered: This paper reviews available evidence to assist clinicians in prescribing of anticoagulation therapy at the extremes of body weight. Expert commentary: There are limited data to guide prescribing of all available anticoagulants at the extremes of weight and further research regarding efficacy and safety outcomes in these groups is required. Laboratory monitoring to guide dosing of traditional anticoagulants provides reassurance of 'predictable' efficacy. In contrast agents that are not routinely monitored by laboratory testing provide greater challenges. For example, underweight patients are at risk of receiving higher drug exposures of DOACs, whereas the use of fixed dose DOACs in obese patients may be associated with lower drug exposures.

Enoxaparin Dosing at Extremes of Weight: Literature Review and Dosing Recommendations

OBJECTIVE

To review the literature on both thromboprophylaxis and treatment of venous thromboembolism (VTE) with enoxaparin in low- and high-body-weight patients and to make dosing and monitoring recommendations in these patient populations.

DATA SOURCES

A search using PubMed was conducted (1995 to January 2018) using the following key words: enoxaparin, body weight, AND thromboprophylaxis, or AND treatment. Additional references were identified from a review of citations.

STUDY SELECTION AND DATA EXTRACTION

Studies included examined the effect of body weight and/or body mass index (BMI) on VTE, bleeding, enoxaparin dosing, and/or anti-Xa concentrations for thromboprophylaxis and treatment-dose enoxaparin. Studies in pediatric and pregnant patients were excluded.

DATA SYNTHESIS

Optimal enoxaparin dosing strategies for VTE prophylaxis and treatment for patients at extremes of weight have not yet been elucidated by clinical trials; however, data suggest that standard dosing regimens may not be appropriate in these patients. Relevance to Patient Care and Clinical Practice: This review provides a thorough discussion on both thromboprophylaxis and treatment of VTE with enoxaparin in low- and high-body-weight patients. It includes dosing recommendations to guide clinicians caring for these patient populations.

CONCLUSIONS

Patients at extremes of weight require special consideration to determine appropriate enoxaparin doses. Specifically, low-body-weight patients may benefit from 30 mg subcutaneously daily for VTE prophylaxis, and standard weight-based dosing for VTE treatment. Conversely, in patients with BMIs ≥40 kg/m², 40 mg subcutaneously twice daily is recommended, with consideration for higher doses in patients with BMIs ≥50 kg/m².

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.

Pentasaccharides for the treatment of deep vein thrombosis

BACKGROUND

Standard treatment of deep vein thrombosis (DVT) is based on antithrombotic therapy, initially with parenteral administration of unfractionated heparin or low molecular weight heparins (LMWH) for five to seven days, then subsequent long-term therapy with oral vitamin K antagonists (e.g. warfarin). Pentasaccharides are novel anticoagulants that may be favourable over standard therapy due to their predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. Heparin-induced thrombocytopenia, a harmful effect of heparins, appears to be rare during treatment with pentasaccharides.

OBJECTIVES

To assess the efficacy and harms of pentasaccharides for the treatment of deep vein thrombosis.

SEARCH METHODS

The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (22 March 2017) and the Cochrane Central Register of Controlled Trials (CENTRAL) (2017, Issue 2) (searched 22 March 2017). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles for additional citations.

SELECTION CRITERIA

We included randomised controlled trials in which people 18 years of age or older with a DVT confirmed by standard imaging techniques were allocated to receive a pentasaccharide (fondaparinux, idraparinux, or idrabiotaparinux) for the treatment of DVT in comparison with standard therapy or other treatments.

DATA COLLECTION AND ANALYSIS

We extracted data characterising the included trials according to the methods, participants, interventions, and outcomes. We assessed risk of bias using Cochrane's 'Risk of bias' tool and employed the GRADE methodology to evaluate the quality of the evidence.The main primary outcome for efficacy was recurrent venous thromboembolism (VTE), and the main primary outcome for harm was major and clinically relevant bleeding. Since our outcomes were dichotomous, we calculated the risk ratio (RR) with a 95% confidence interval (CI). We combined the effects of different comparisons through a meta-analysis using a fixed-effect model.

MAIN RESULTS

We included five randomised controlled trials of 6981 participants comparing pentasaccharides with standard therapy or other pentasaccharides. The quality of the evidence varied depending on the outcome and was judged as of moderate to very low quality. We downgraded the quality of the evidence due to risk of bias or imprecision, or both.Two studies evaluated fondaparinux, at doses of 5.0 mg, 7.5 mg, and 10.0 mg, plus vitamin K antagonist in comparison with standard therapy. A meta-analysis of these two studies showed no clear difference in the risk of recurrent VTE (RR 0.80, 95% CI 0.43 to 1.47; 2658 participants); moderate-quality evidence. The frequencies of major bleeding were similar between interventions in the initial period of treatment (approximately five days) (RR 1.15, 95% CI 0.39 to 3.44; 2645 participants) and at three months' follow-up (RR 1.05, 95% CI 0.64 to 1.71; 2645 participants). We judged the quality of the evidence as moderate.One study (757 participants) compared idrabiotaparinux (3.0 mg) with idraparinux (2.5 mg) and demonstrated no clear difference in the risk of recurrent VTE at six months' follow-up (RR 0.72, 95% CI 0.31 to 1.69); low-quality evidence. Major bleeding during the initial treatment period was not reported. Major bleeding at six-month follow-up was less frequent in participants receiving idrabiotaparinux versus participants treated with idraparinux (RR 0.21, 95% CI 0.06 to 0.71); low-quality evidence.The effect of an initial treatment with LMWH followed by three months of idraparinux (10 mg) showed no clear difference from standard therapy for risk of recurrent VTE (RR 1.51, 95% CI 0.26 to 8.90; 263 participants); very low-quality evidence; one study. Major bleeding during the initial treatment period was not reported. The frequency of major and other clinically relevant bleeding at three months' follow-up ranged from 2% to 15% in participants receiving LMWH and increasing doses of idraparinux of 2.5 mg, 5 mg, 7.5 mg, or 10 mg. When dosage groups were combined, there was no clear difference in major plus other clinically relevant bleeding or in major bleeding alone between the idraparinux treatment group and the standard therapy group (RR 1.30, 95% CI 0.70 to 2.40; 659 participants; RR 3.76, 95% CI 0.50 to 28.19; 659 participants, respectively); very low-quality evidence.One study (2904 participants) compared idraparinux (2.5 mg) to standard therapy. There was no clear difference in the risk of recurrent VTE at three months' follow-up (RR 0.98, 95% CI 0.64 to 1.48); low-quality evidence. Major bleeding during the initial treatment period was not reported. Major bleeding at three months of follow-up appeared to be similar in the idraparinux group and the standard therapy group (RR 0.71, 95% CI 0.34 to 1.47); very low-quality evidence.

AUTHORS' CONCLUSIONS

We found moderate-quality evidence that the effects of fondaparinux at doses of 5.0 mg, 7.5 mg, and 10.0 mg plus vitamin K antagonist are similar in terms of recurrent VTE and risk of major bleeding compared with standard treatment for DVT.Low-quality evidence suggests equal efficacy of idraparinux at 2.5 mg and the equimolar dose of 3.0 mg of idrabiotaparinux with regard to recurrent VTE, but a higher frequency of major bleeding was observed in participants treated with idraparinux.We judged evidence on the effectiveness of idraparinux compared with standard therapy, with or without initial treatment with LMWH, and on associated bleeding risk to be low to very low quality, therefore we have very limited confidence in the estimated effects.The observed similar effectiveness in terms of recurrent DVT and harmful effects in terms of bleeding risk with fondaparinux plus vitamin K antagonist compared to standard treatment for DVT suggest that it may be an alternative to conventional anticoagulants for the treatment of DVT in certain circumstances.

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.

Therapeutic monitoring of unfractionated heparin - trials and tribulations

INTRODUCTION

Heparin is one of the oldest biological medicines with an established role in prevention and treatment of arterial and venous thromboembolism. Published therapeutic ranges for unfractionated heparin (UFH) mostly precede the large increase in the number of activated partial thromboplastin time (APTT) reagent/instrument combinations that now show wide variability. Areas covered: This paper explores the use of UFH, the development of heparin therapeutic ranges (HTRs), and the strengths and limitations of the methods used to monitor heparin's anticoagulant effect. Expert commentary: Despite longstanding use of UFH for management of thromboembolic conditions, the optimal test for monitoring UFH remains undetermined. Although used extensively for monitoring UFH, routine APTT-derived HTRs are based on limited science that may have little relevance to current laboratory practice. Anti-FXa levels may provide better and more reliable HTRs; however, even these levels show considerable inter-laboratory variation, and there are insufficient clinical studies proving improved clinical efficacy. Alternative tests for monitoring UFH reported over time have not been proven effective nor feasible, secondary to technical or cost issues, or lack of general adoption. Thus, despite limited evidence of clinical utility, an uncomfortable marriage of convenience represented by heparin laboratory monitoring is unlikely to be terminated in the immediate future.

Clinical outcomes during anticoagulant therapy in fragile patients with venous thromboembolism

BACKGROUND

Subgroup analyses from randomized trials suggested favorable results for the direct oral anticoagulants in fragile patients with venous thromboembolism (VTE). The frequency and natural history of fragile patients with VTE have not been studied yet.

OBJECTIVES

To compare the clinical characteristics, treatment and outcomes during the first 3 months of anticoagulation in fragile vs non-fragile patients with VTE.

METHODS

Retrospective study using consecutive patients enrolled in the RIETE (Registro Informatizado Enfermedad TromboEmbolica) registry. Fragile patients were defined as those having age ≥75 years, creatinine clearance (CrCl) levels ≤50 mL/min, and/or body weight ≤50 kg.

RESULTS

From January 2013 to October 2016, 15 079 patients were recruited. Of these, 6260 (42%) were fragile: 37% were aged ≥75 years, 20% had CrCl levels ≤50 mL/min, and 3.6% weighed ≤50 kg. During the first 3 months of anticoagulant therapy, fragile patients had a lower risk of VTE recurrences (0.78% vs 1.4%; adjusted odds ratio [OR]: 0.52; 95% confidence intervals [CI]: 0.37-0.74) and a higher risk of major bleeding (2.6% vs 1.4%; adjusted OR: 1.41; 95% CI: 1.10-1.80), gastrointestinal bleeding (0.86% vs 0.35%; adjusted OR: 1.84; 95% CI: 1.16-2.92), haematoma (0.51% vs 0.07%; adjusted OR: 5.05; 95% CI: 2.05-12.4), all-cause death (9.2% vs 3.5%; adjusted OR: 2.02; 95% CI: 1.75-2.33), or fatal PE (0.85% vs 0.35%; adjusted OR: 1.77; 95% CI: 1.10-2.85) than the non-fragile.

CONCLUSIONS

In real life, 42% of VTE patients were fragile. During anticoagulation, they had fewer VTE recurrences and more major bleeding events than the non-fragile.

Monitoring Low Molecular Weight Heparins with antiXa Activity: House of Cards or Firm Foundation?

This feature examines the impact of pharmacologic interventions on the treatment of the critically ill patient — an area of health care that has become increasingly complex. It will review recent advances (including evolving and controversial data) in drug therapy for adult ICU patients and assess these new modalities in terms of clinical, humanistic, and economic outcomes.

Dosing considerations in the use of the direct oral anticoagulants in the antiphospholipid syndrome

WHAT IS KNOWN AND OBJECTIVES

At least four prospective trials have been initiated investigating the direct oral anticoagulants in the antiphospholipid syndrome. Preliminary reports have supported their use in patients with a history of venous thrombosis and a target INR of 2-3, but there have also been reports of failure of these agents in the antiphospholipid syndrome. The objective is to present a case report that illustrates there may be important dosing issues when considering the use of these agents in patients with the antiphospholipid syndrome.

CASE SUMMARY

A 50-year-old woman with the antiphospholipid syndrome, manifesting clinically with recurrent pyoderma gangrenosum-like leg ulcers, was treated with apixaban, resulting in improved ulcer healing. For insurance purposes, she was switched to rivaroxaban with worsening of the ulcers which again improved when apixaban was resumed.

WHAT IS NEW AND CONCLUSION

Despite a similar half-life, pharmacokinetics and pharmacodynamics, the manufacturer-recommended maintenance dosing of apixaban is twice daily and rivaroxaban once daily. We believe this difference in recommended dose accounts for the differential clinical response noted in the present case report and that twice daily dosing and a larger daily dose of these agents may be more efficacious in potent hypercoagulable disorders, such as the antiphospholipid syndrome.

Monitoring Enoxaparin with Antifactor Xa Levels in Obese Patients

STUDY OBJECTIVES

To characterize antifactor Xa peak levels (as therapeutic, subtherapeutic, and supratherapeutic) in morbidly obese patients receiving treatment doses of enoxaparin, using a therapeutic range of 0.5-1.1 units/ml, and to assess the occurrence of bleeding complications in these patients.

DESIGN

Retrospective cohort study.

SETTING

Community hospital.

PATIENTS

Ninety-nine morbidly obese patients (body mass index [BMI] higher than 40 kg/m(2) or total body weight more than 150 kg) who received at least three doses of the standard treatment dosage of enoxaparin and had steady-state antifactor Xa peak levels between April 2009 and January 2014.

MEASUREMENTS AND MAIN RESULTS

Data were collected from patients' medical records on age, sex, height, weight, BMI, serum creatinine concentration, creatinine clearance (using lean body weight as well as adjusted body weight), antifactor Xa level, and time of blood collection for measurement of antifactor Xa level. Enoxaparin therapy was monitored by using antifactor Xa levels; steady-state enoxaparin antifactor Xa levels were measured 4 hours after administration of the third dose for peak level monitoring. The primary outcome was the proportion of patients whose steady-state antifactor Xa peak values were in the therapeutic (0.5-1.1 units/ml), subtherapeutic, and supratherapeutic ranges. The secondary outcome was occurrence of major bleeding. Univariate regression analysis was performed to identify the correlation between baseline patient characteristics and antifactor Xa levels. Most of the patients (50 [50.5%]) had supratherapeutic levels, 35 (35.4%) had levels within the therapeutic peak range (0.5-1.1 units/ml), and 14 (14.1%) had subtherapeutic levels. No bleeding was observed in any of the 99 patients. Univariate analysis revealed a negative association between antifactor Xa levels and serum creatinine concentration (r = -0.262, p=0.009).

CONCLUSION

Based on the results of this study, monitoring antifactor Xa levels is warranted to ensure the safety and efficacy of enoxaparin in the obese patient population (defined as a total body weight more than 150 kg or BMI higher than 40 kg/m(2)). Enoxaparin dose individualization and antifactor Xa level monitoring need further validation with clinical outcomes.

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.

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

BACKGROUND

Low molecular weight heparins (LMWHs) have been shown to be effective and safe in preventing venous thromboembolism (VTE). They may also be effective for the initial treatment of VTE. This is the third update of the Cochrane Review first published in 1999.

OBJECTIVES

To evaluate the efficacy and safety of fixed dose subcutaneous low molecular weight heparin compared to adjusted dose unfractionated heparin (intravenous or subcutaneous) for the initial treatment of people with venous thromboembolism (acute deep venous thrombosis or pulmonary embolism).

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist (CIS) searched the Cochrane Vascular Specialised Register (15 September 2016). In addition the CIS searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8) in the Cochrane Library (searched 15 September 2016) and trials' registries.

SELECTION CRITERIA

Randomised controlled trials comparing fixed dose subcutaneous LMWH with adjusted dose intravenous or subcutaneous unfractionated heparin (UFH) in people with VTE.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed for quality and extracted data.

MAIN RESULTS

Six studies were added to this update resulting in a total of 29 included studies (n = 10,390). The quality of the studies was downgraded as there was a risk of bias in some individual studies relating to risk of attrition and reporting bias; in addition several studies did not adequately report on the randomisation methods used nor on how the treatment allocation was concealed.During the initial treatment period, the incidence of recurrent venous thromboembolic events was lower in participants treated with LMWH than in participants treated with UFH (Peto odds ratio (OR) 0.69, 95% confidence intervals (CI) 0.49 to 0.98; 6238 participants; 18 studies; P = 0.04; moderate-quality evidence). After a follow-up of three months, the period in most of the studies for which oral anticoagulant therapy was given, the incidence of recurrent VTE was lower in participants treated with LMWH than in participants with UFH (Peto OR 0.71, 95% CI 0.56 to 0.90; 6661 participants; 16 studies; P = 0.005; moderate-quality evidence). Furthermore, at the end of follow-up, LMWH was associated with a lower rate of recurrent VTE than UFH (Peto OR 0.72, 95% CI 0.59 to 0.88; 9489 participants; 22 studies; P = 0.001; moderate-quality evidence). LMWH was also associated with a reduction in thrombus size compared to UFH (Peto OR 0.71, 95% CI 0.61 to 0.82; 2909 participants; 16 studies; P < 0.00001; low-quality evidence), but there was moderate heterogeneity (I² = 56%). Major haemorrhages occurred less frequently in participants treated with LMWH than in those treated with UFH (Peto OR 0.69, 95% CI 0.50 to 0.95; 8780 participants; 25 studies; P = 0.02; moderate-quality evidence). There was no difference in overall mortality between participants treated with LMWH and those treated with UFH (Peto OR 0.84, 95% CI 0.70 to 1.01; 9663 participants; 24 studies; P = 0.07; moderate-quality evidence).

AUTHORS' CONCLUSIONS

This review presents moderate-quality evidence that fixed dose LMWH reduced the incidence of recurrent thrombotic complications and occurrence of major haemorrhage during initial treatment; and low-quality evidence that fixed dose LMWH reduced thrombus size when compared to UFH for the initial treatment of VTE. There was no difference in overall mortality between participants treated with LMWH and those treated with UFH (moderate-quality evidence). The quality of the evidence was assessed using GRADE criteria and downgraded due to concerns over risk of bias in individual trials together with a lack of reporting on the randomisation and concealment of treatment allocation methods used. The quality of the evidence for reduction of thrombus size was further downgraded because of heterogeneity between studies.

Choosing the Appropriate Antithrombotic Agent for the Prevention and Treatment of VTE: A Case-Based Approach

Objective:

To review the risk of venous thromboembolism (VTE) in various patient populations and evaluate the agents available for the prevention and treatment of VTE using a case-based approach.

Data Sources:

A MEDLINE search (1995–July 2006) was conducted to identify relevant literature. Additional references were reviewed from selected articles.

Study Selection and Data Extraction:

Articles related to the prevention of VTE in orthopedic surgery, general surgery, and medically ill patients, as well as the treatment of VTE, were reviewed.

Data Synthesis:

Pharmacologic options for the prevention and treatment of VTE include warfarin, unfractionated heparin (UFH), low-molecular-weight heparins (LMWH), and fondaparinux. Current guidelines support the use of warfarin, LMWH, or fondaparinux for VTE prophylaxis following lower limb major orthopedic surgery. For VTE prophylaxis in hospitalized medical patients or patients undergoing general surgery, use of UFH and LMWH is supported; however, recent data on fondaparinux suggest that it is also effective in these patient populations. The use of UFH or LMWH (both in conjunction with warfarin) for treatment of acute deep venous thrombosis or nonmassive pulmonary embolism is recommended. Recent data suggest that fondaparinux (in conjunction with warfarin) is also effective for the treatment of VTE. A variety of pharmacokinetic, pharmacodynamic, and pharmacoeconomic factors differentiate each agent for the various indications.

Conclusions:

Currently, a “one-size-fits-all” anticoagulant is not available for treatment of VTE. A variety of patient factors, including type of surgery, medical indication, thrombotic risk factors, bleeding risk, history of heparin-induced thrombocytopenia, and a variety of comorbid conditions can affect the safety, efficacy, and selection of appropriate VTE therapy.

In-Hospital Management and Follow-Up Treatment of Venous Thromboembolism: Focus on New and Emerging Treatments

Venous thromboembolism (VTE), encompassing pulmonary embolism (PE) and deep venous thrombosis (DVT), is a major cause of morbidity and mortality of particular relevance for intensivists and hospitalists. Acute VTE is usually managed with parenteral unfractionated heparin or low-molecular-weight heparin, followed by an oral vitamin K antagonist. Data are lacking for optimal treatment of less common occurrences, such as upper extremity DVT, and for approaches such as thrombolysis for PE associated with early signs of hemodynamic compromise or inferior vena cava filters when anticoagulation is contraindicated. Direct oral anticoagulants (DOACs) including apixaban, dabigatran, edoxaban, and rivaroxaban are now added to the armamentarium of agents available for acute management of VTE and/or reducing the risk of recurrence. This review outlines an algorithmic approach to acute VTE treatment: from aggressive therapies when anticoagulation may be inadequate, to alternative choices when anticoagulation is contraindicated, to anticoagulant options in the majority of patients in whom anticoagulation is appropriate. Evidence-based guidelines and the most recent DOAC clinical trial data are discussed in the context of the standard of care. Situations and treatment approaches for which data are unavailable or insufficient are identified. VTE therapy in care transitions is discussed, as are choices for secondary prevention.

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 practical management of the heparin anticoagulants in the treatment of venous thromboembolism

Venous thromboembolism (VTE) is a serious and often fatal medical condition with an increasing incidence. Despite the changing landscape of VTE treatment with the introduction of the new direct oral anticoagulants many uncertainties remain regarding the optimal use of traditional parenteral agents. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. This specific chapter addresses the practical management of heparins including low molecular weight heparins and fondaparinux. For each anticoagulant a list of the most common practice related questions were created. Each question was addressed using a brief focused literature review followed by a multidisciplinary consensus guidance recommendation. Issues addressed included initial anticoagulant dosing recommendations, recommended baseline laboratory monitoring, managing dose adjustments, evidence to support a relationship between laboratory tests and meaningful clinical outcomes, special patient populations including extremes of weight and renal impairment, duration of necessary parenteral therapy during the transition to oral therapy, candidates for outpatient treatment where appropriate and management of over-anticoagulation and adverse effects including bleeding and heparin induced thrombocytopenia. This article concludes with a concise table of clinical management questions and guidance recommendations to provide a quick reference for the practical management of heparin, low molecular weight heparin and fondaparinux.

Critical Review and Update on the Treatment of Acute and Chronic Pulmonary Embolism

Pulmonary embolism (PE), can be life-threatening without rapid appropriate therapy and often leads to chronic disease and disability. The ambiguity of symptoms makes PE difficult to diagnose, and available imaging strategies have their limitations. Treatment options for acute PE include fibrinolytics, surgical embolectomy, catheter-directed treatment, or vena cava filter placement as well as traditional parenteral anticoagulants, used alone or as a bridge to a vitamin K antagonist (VKA). The direct oral anticoagulants (DOACs) rivaroxaban and apixaban allow for single drug therapy, eliminating the need for initial parenteral anticoagulation, while dabigatran and edoxaban are initiated after a short course of parenteral therapy. The DOACs serve as a viable alternative to warfarin for chronic management for PE. Pulmonary embolism provoked from transient risk factors often requires a short-term course of anticoagulation (3 months). Unprovoked events, and those that occur in the presence of continuing risk factors such as cancer, or clinical markers such as residual vein thrombosis and elevated d-dimers can predict a higher risk of recurrent events and warrant extended anticoagulation. This review evaluates current recommendations for the treatment of PE, including dosing strategies, duration of therapy, and special populations such as renal impairment, malignancy, and obesity.

Postoperative Acute Pulmonary Embolism Following Pulmonary Resections

Postoperative acute pulmonary embolism after pulmonary resections is highly fatal complication. Many literatures have documented cancer to be the highest risk factor for acute pulmonary embolism after pulmonary resections. Early diagnosis of acute pulmonary embolism is highly recommended and computed tomographic pulmonary angiography is the gold standard in diagnosis of acute pulmonary embolism. Anticoagulants and thrombolytic therapy have shown a great success in treatment of acute pulmonary embolism. Surgical therapies (embolectomy and inferior vena cava filter replacement) proved to be lifesaving but many literatures favored medical therapy as the first choice. Prophylaxis pre and post operation is highly recommended, because there were statistical significant results in different studies which supported the use of prophylaxis in prevention of acute pulmonary embolism. Having reviewed satisfactory number of literatures, it is suggested that thoroughly preoperative assessment of patient conditions, determining their risk factors complicating to pulmonary embolism and the use of appropriate prophylaxis measures are the key options to the successful minimization or eradication of acute pulmonary embolism after lung resections.

Guideline on aspects of cancer-related venous thrombosis

The guideline was drafted by a writing group identified by the Haemostasis and Thrombosis Task Force of the British Committee for Standards in Haematology (BCSH). All the authors are consultants in haematology in the UK. A search was performed of PubMed and Embase using the term 'cancer' combined with 'thrombosis', 'treatment', 'prophylaxis' and 'clinical presentation'. The search covered articles published up until December 2014. Only human studies were included and articles not written in English were excluded. References in recent reviews were also examined. The writing group produced the draft guideline, which was subsequently revised by consensus by members of the Haemostasis and Thrombosis Task Force of the BCSH and the BCSH executive. The guideline was then reviewed by the sounding board of the British Society for Haematology (BSH). This comprises 50 or more members of the BSH who have reviewed the guidance and commented on the content and application to the UK setting. The 'GRADE' system was used to quote levels and grades of evidence, details of which can be found at: http://www.bcshguidelines.com/BCSH_PROCESS/EVIDENCE_LEVELS_AND_GRADES_OF_RECOMMENDATION/43_GRADE.html. The objective of this guideline is to provide healthcare professionals with clear guidance on the prevention and management of venous thromboembolism (VTE) in patients with cancer and to advise on an approach to screening for cancer in patients with unprovoked VTE in whom cancer was not initially suspected based on clinical grounds.

Treatment of deep vein thrombosis in patients with pulmonary embolism: subgroup analysis on the efficacy and safety of certoparin vs. unfractionated heparin

The objective of this subgroup analysis of the pivotal studies NMH-TH-3 and NMH-TH-4 was to investigate the incidence of recurrent events of venous thromboembolism in patients with acute deep vein thrombosis (DVT) with and without pulmonary embolism treated with subcutaneous fixed-dose low-molecular-weight heparin certoparin or intravenous unfractionated heparin (UFH). To assess whether the efficacy of the two treatments is modified by the presence or absence of pulmonary embolism, a P value for subgroup by treatment interaction was calculated using logistic regression. The rate of recurrent venous thromboembolic events, defined as DVT, pulmonary embolism and death due to pulmonary embolism, was observed over 6 months. After 6 months of follow-up, 6.58% of patients with pulmonary embolism at baseline treated with certoparin (5/76) compared with 11.5% of patients with pulmonary embolism at baseline treated with UFH (7/61) had a venous thromboembolic event [relative risk (RR) = 0.57, confidence interval (CI) = 0.19-1.72]. In the group of patients without pulmonary embolism at baseline, 2.82% of patients treated with certoparin (23/816) and 4.63% of patients treated with UFH (37/800) had a venous thromboembolic event (RR = 0.61, CI = 0.37-1.02). The test for interaction between the groups of patients with and without pulmonary embolism was not significant (P = 0.886). The same was true for the safety results with regard to major bleedings and death. These data suggest that the recommendation for the use of certoparin in the treatment of isolated DVT can safely be extended to treatment of DVT in patients concomitantly suffering from pulmonary embolism.

Canadian consensus recommendations on the management of venous thromboembolism in patients with cancer. Part 2: treatment

Patients with cancer are at increased risk of venous thromboembolism (vte). Anticoagulation therapy is used to treat vte; however, patients with cancer have unique clinical circumstances that can often make decisions surrounding the administration of therapeutic anticoagulation complicated. No national Canadian guidelines on the management of established cancer-associated thrombosis have been published. We therefore aimed to develop a consensus-based, evidence-informed guideline on the topic. PubMed was searched for clinical trials and meta-analyses published between 2002 and 2013. Reference lists of key articles were hand-searched for additional publications. Content experts from across Canada were assembled to review the evidence and make recommendations. Low molecular weight heparin is the treatment of choice for cancer patients with established vte. Direct oral anticoagulants are not recommended for the treatment of vte at this time. Specific clinical scenarios, including the presence of an indwelling venous catheter, renal insufficiency, and thrombocytopenia, warrant modifications in the therapeutic administration of anticoagulation therapy. Patients with recurrent vte should receive extended (>3 months) anticoagulant therapy. Incidental vte should generally be treated in the same manner as symptomatic vte. There is no evidence to support the monitoring of anti-factor Xa levels in clinically stable cancer patients receiving prophylactic anticoagulation; however, levels of anti-factor Xa could be checked at baseline and periodically thereafter in patients with renal insufficiency. Follow-up and education about the signs and symptoms of vte are important components of ongoing patient care.

Once daily versus twice daily enoxaparin for acute pulmonary embolism in cancer patients

Background

Venous thromboembolism (VTE) is a condition in which a thrombus occludes the vasculature. The incidence of VTE in cancer patients is three times higher than that of the general population. Enoxaparin 1 mg/kg subcutaneously (SC) twice daily and enoxaparin 1.5 mg/kg SC once daily are both FDA-approved dosing regimens for the treatment of pulmonary embolism (PE). The objectives of this study were to assess outcomes of cancer patients treated with once or twice daily enoxaparin for acute PE. Primary outcomes included recurrent or worsening PE and secondary outcomes included mortality or signs of clinically overt, major bleeding.

Methods

This study was a retrospective chart review of adult cancer patients treated at The University of Texas MD Anderson Cancer Center from 2011 to 2013 who received either 1 mg/kg twice daily or 1.5 mg/kg once daily enoxaparin for acute PE upon discharge.

Results

Among 48 patients in each the twice daily and once daily group, six recurrent PEs occurred. The incidence of recurrent PE was higher in the once daily group ( n = 4) versus twice daily group ( n = 2). More major bleeding events occurred in the once daily group than the twice daily group (15% vs. 6%). Mortality at 6 months was higher in the twice daily group versus once daily group (13% vs. 6%).

Conclusion

Cancer patients receiving once daily enoxaparin for the treatment of acute PE may be at increased risk of recurrent PE and clinically overt bleeding. Larger randomized trials are needed to confirm the results of this study.

Impact of thromboprophylaxis across the US acute care setting

Background

The risk of venous thromboembolism (VTE) can be reduced by appropriate use of anticoagulant prophylaxis. VTE prophylaxis does, however, remain substantially underused, particularly among acutely ill medical inpatients. We sought to evaluate the clinical and economic impact of increasing use of American College of Chest Physicians (ACCP)-recommended VTE prophylaxis among medical inpatients from a US healthcare system perspective.

Methods and Findings

In this retrospective database cost-effectiveness evaluation, a decision-tree model was developed to estimate deaths within 30 days of admission and outcomes attributable to VTE that might have been averted by use of low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH). Incremental cost-effectiveness ratio was calculated using “no prophylaxis” as the comparator. Data from the ENDORSE US medical inpatients and the US nationwide Inpatient Sample (NIS) were used to estimate the annual number of eligible inpatients who failed to receive ACCP-recommended VTE prophylaxis. The cost-effectiveness analysis indicated that VTE-prevention strategies would reduce deaths by 0.5% and 0.3%, comparing LMWH and UFH strategies with no prophylaxis, translating into savings of $50,637 and $25,714, respectively, per death averted. The ENDORSE findings indicated that 51.1% of US medical inpatients were at ACCP-defined VTE risk, 47.5% of whom received ACCP-recommended prophylaxis. By extrapolating these findings to the NIS and applying cost-effectives analysis results, the full implementation of ACCP guidelines would reduce number of deaths (by 15,875 if using LMWH or 10,201 if using UFH), and was extrapolated to calculate the cost reduction of $803M for LMWH and $262M for UFH.

Conclusions

Efforts to improve VTE prophylaxis use in acutely ill inpatients are warranted due to the potential for reducing VTE-attributable deaths, with net cost savings to healthcare systems.

Acute pancreatitis complicated by massive inferior vena cava and right atrial thrombosis: a case report

Venous thrombosis is a relatively common complication of acute pancreatitis. A 58-year-old man came to our emergency department with abdominal pain. Pancreatitis complicated with a huge thrombosis through inferior vena cava (IVC) to right atrium and left renal vein was diagnosed. Gabexate and enoxaparin were administered for pancreatitis and thrombosis. Surgical removal of thrombosis was considered but was not possible because of poor general condition. Despite conservative management, the patient expired. We believe this is the first case of pancreatitis complicated by right atrial thrombosis.

Applying new strategies for the national adaptation, updating, and dissemination of trustworthy guidelines: results from the Norwegian adaptation of the Antithrombotic Therapy and the Prevention of Thrombosis, 9th Ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

The Antithrombotic Therapy and the Prevention of Thrombosis, 9th Edition: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (AT9) represent trustworthy international guidelines for antithrombotic treatment and thromboprophylaxis. We describe major changes to the format and content resulting from applying new strategies for guideline adaptation and dissemination.

METHODS

A Norwegian guideline panel of 46 experts completed a structured and systematic adaptation process, updated the recommendations based on new evidence, and rewrote the recommendations in an electronic multilayered presentation format. We published the adapted guideline using the web-based Making GRADE the Irresistible Choice Guideline Authoring and Publication Platform.

RESULTS

We applied a novel presentation format to 333 recommendations from 11 of the 15 management chapters in AT9 and condensed and restructured them into 249 recommendations in a multilayered format. We added additional relevant information, such as 29 best-practice statements about new oral anticoagulants and practical information sections for 121 recommendations. Common reasons for modifications included feasibility of the recommendations in a national context, disagreement with applied baseline risk estimates, and reevaluation of the balance between the benefits and harms of interventions in relation to assumed typical patient preferences and values. The adapted guideline was published and disseminated online in November 2013.

CONCLUSIONS

New strategies for adapting, updating, and disseminating trustworthy guidelines proved feasible and will provide Norwegian health-care professionals and patients with up-to-date guidance tailored to national circumstances.

Adverse outcomes of anticoagulant use among hospitalized patients with chronic kidney disease: a comparison of the rates of major bleeding events between unfractionated heparin and enoxaparin

Background

Anticoagulation therapy is usually required in patients with chronic kidney disease (CKD) for treatment or prevention of thromboembolic diseases. However, this benefit could easily be offset by the risk of bleeding.

Objectives

To determine the incidence of adverse outcomes of anticoagulants in hospitalized patients with CKD, and to compare the rates of major bleeding events between the unfractionated heparin (UFH) and enoxaparin users.

Methods

One year prospective observational study was conducted in patients with CKD stages 3 to 5 (estimated GFR, 10–59 ml/min/1.73 m²) who were admitted to the renal unit of Dubai Hospital. Propensity scores for the use of anticoagulants, estimated for each of the 488 patients, were used to identify a cohort of 117 pairs of patients. Cox regression method was used to estimate association between anticoagulant use and adverse outcomes.

Results

Major bleeding occurred in 1 in 3 patients who received anticoagulation during hospitalization (hazard ratio [HR], 4.61 [95% confidence interval [CI], 2.05–10.35]). Compared with enoxaparin users, patients who received anticoagulation with unfractionated heparin had a lower mean [SD] serum level of platelet counts (139.95 [113]×10³/µL vs 205.56 [123] ×10³/µL; P<0.001), and had a higher risk of major bleeding (HR, 4.79 [95% CI, 1.85–12.36]). Furthermore, compared with those who did not receive anticoagulants, patients who did had a higher in-hospital mortality (HR, 2.54 [95% CI, 1.03–6.25]); longer length of hospitalization (HR, 1.04 [95% CI, 1.01–1.06]); and higher hospital readmission at 30 days (HR, 1.79 [95% CI, 1.10–2.91]).

Conclusions

Anticoagulation among hospitalized patients with CKD was significantly associated with an increased risk of bleeding and in-hospital mortality. Hence, intensive monitoring and preventive measures such as laboratory monitoring and/or dose adjustment are warranted.

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

BACKGROUND

Compared with patients without cancer, patients 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 patients with cancer.

SEARCH METHODS

A comprehensive search for studies of anticoagulation in patients with cancer including a February 2013 electronic search of: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and ISI Web of Science.

SELECTION CRITERIA

Randomized clinical trials (RCTs) comparing LMWH, UFH, and fondaparinux in patients with cancer and objectively confirmed VTE.

DATA COLLECTION AND ANALYSIS

Using a standardized data form, review authors extracted data in duplicate on methodologic quality, participants, interventions, and outcomes of interest that included mortality, recurrent VTE, major bleeding, minor bleeding, postphlebitic syndrome, quality of life, and thrombocytopenia.

MAIN RESULTS

Of 9559 identified citations, 16 RCTs were eligible: 13 compared LMWH with UFH, two compared fondaparinux with heparin, and one compared dalteparin with tinzaparin. Meta-analysis of 11 studies showed a statistically significant reduction in mortality at three months of follow-up with LMWH compared with UFH (risk ratio (RR) 0.71; 95% confidence interval (CI) 0.52 to 0.98). There was little change in the effect estimate after excluding studies of lower methodologic quality (RR 0.72; 95% CI 0.52 to 1.00). A meta-analysis of three studies comparing LMWH with UFH showed no statistically significant reduction in VTE recurrence (RR 0.78; 95% CI 0.29 to 2.08). The overall quality of evidence was low for LMWH versus UFH due to imprecision and likely publication bias. There were no statistically significant differences between heparin and fondaparinux for the outcomes of mortality (RR 1.27; 95% CI 0.88 to 1.84), recurrent VTE (RR 0.95; 95% CI 0.57 to 1.60), major bleeding (RR 0.79; 95% CI 0.39 to1.63), or minor bleeding (RR 1.50; 95% CI 0.87 to 2.59). The one study comparing dalteparin with tinzaparin found no statistically significant difference in mortality (RR 0.86; 95% CI 0.43 to 1.73).

AUTHORS' CONCLUSIONS

LMWH is possibly superior to UFH in the initial treatment of VTE in patients with cancer. Additional trials focusing on patient-important outcomes will further inform the questions addressed in this review.

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

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