Management of Venous Thromboembolism: Recent Advances in Oral Anticoagulation Therapy

Does the choice of chemoprophylaxis affect the prevention of deep vein thrombosis in lumbar fusion surgery? A systematic review of the literature

Introduction

To date, the available guidance on venous thromboembolism (VTE) prevention in elective lumbar fusion surgery is largely open to surgeon interpretation and preference without any specific suggested chemoprophylactic regimen.

Research question

This study aimed to comparatively analyze the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) with the use of commonly employed chemoprophylactic agents such as unfractionated heparin (UH) and low molecular weight heparin (LMWH) in lumbar fusion surgery.

Material and methods

An independent systematic review of four scientific databases (PubMed, Scopus, clinicaltrials.gov, Web of Science) was performed to identify relevant articles as per the preferred reporting in systematic reviews and meta-analysis (PRISMA) guidelines. Studies reporting on DVT/PE outcomes of lumbar fusion surgery in adult patients with UH or LMWH chemoprophylaxis were included for analysis. Analysis was performed using the Stata software.

Results

Twelve studies with 8495 patients were included in the analysis. A single-arm meta-analysis of the included studies found a DVT incidence of 14% (95%CI [8%-20%]) and 1% (95%CI [-6% - 8%]) with LMWH and UH respectively. Both the chemoprophylaxis agents prevented PE with a noted incidence of 0% (95%CI [0%-0.1%]) and 0% (95%CI [0%-1%]) with LMWH and UH respectively. The risk of bleeding-related complications with the usage of LMWH and UH was 0% (95% CI [0.0%-0.30%]) and 3% (95% CI [0.3%-5%]) respectively.

Discussion and conclusion

Both LMWH and UH reduces the overall incidence of DVT/PE, but there is a paucity of evidence analyzing the comparative effectiveness of the chemoprophylaxis regimens in lumbar fusion procedures. The heterogeneity in data prevents any conclusions, as there remains an evidence gap. We recommend future high-quality randomized controlled trials to investigate in this regard to help develop recommendations on thromboprophylaxis usage.

Tailoring Apixaban in Nanostructured Lipid Carrier Enhancing Its Oral Bioavailability and Anticoagulant Activity

Apixaban (Apx), an oral anticoagulant drug, is a direct factor Xa inhibitor for the prophylaxis against venous thromboembolism. Apx has limited oral bioavailability and poor water solubility. The goal of this study was to improve the formulation of an Apx-loaded nanostructured lipid carrier (NLC) to increase its bioavailability and effectiveness. As solid lipid, liquid lipid, hydrophilic, and lipophilic stabilizers, stearic acid, oleic acid, Tween 80, and lecithin were used, respectively. Utilizing Box-Behnken design, the effects of three factors on NLC particle size (Y1), zeta potential (Y2), and entrapment efficiency percent (Y3) were examined and optimized. The optimized formula was prepared, characterized, morphologically studied, and pharmacokinetically and pharmacodynamically assessed. The observed responses of the optimized Apx formula were 315.2 nm, -43.4 mV, and 89.84% for Y1, Y2, and Y3, respectively. Electron microscopy revealed the homogenous spherical shape of the NLC particles. The in vivo pharmacokinetic study conducted in male Wistar rats displayed an increase in AUC and Cmax by 8 and 2.67 folds, respectively, compared to oral Apx suspension. Moreover, the half-life was increased by 1.94 folds, and clearance was diminished by about 8 folds, which makes the NLC formula a promising sustained release system. Interestingly, the pharmacodynamic results displayed the superior effect of the optimized formula over the drug suspension with prolongation in the cuticle bleeding time. Moreover, both prothrombin time and activated partial thromboplastin time are significantly increased. So, incorporating Apx in an NLC formula significantly enhanced its oral bioavailability and pharmacodynamic activity.

Rivaroxaban Prophylaxis in Noncirrhotic Portal Vein Thrombosis

BACKGROUND: In patients with noncirrhotic chronic portal vein thrombosis (PVT), the benefit of long-term anticoagulation is unknown. We assessed the effects of rivaroxaban on the risk of venous thromboembolism and portal hypertension-related bleeding in such patients. METHODS: In this multicenter, controlled trial, we randomly assigned patients with noncirrhotic chronic PVT without major risk factors for thrombosis to receive either rivaroxaban 15 mg/day or no anticoagulation. The primary end point was 2-year thrombosis-free survival. Secondary end points included the occurrence of site-specific thromboses and major bleeding events. RESULTS: A total of 111 participants were enrolled in the trial, with a mean age of 50.4±13.2 years; 58% of participants were men. An unplanned interim analysis was requested by the independent data safety monitoring board (DSMB) after 10 thrombotic events occurred. The thrombosis incidence rate was 0 per 100 person-years in the rivaroxaban group and 19.71 per 100 person-years (95% confidence interval, 7.49 to 31.92) in the no anticoagulation group (log-rank P=0.0008) after a median follow-up of 11.8 months. Based on the interim analysis, the DSMB recommended switching patients from the no anticoagulation group to anticoagulation. After a median follow-up of 30.3 months (intraquartile range, 24.3 to 47.8), major bleeding occurred in two patients receiving rivaroxaban and in one patient not receiving anticoagulation. No deaths occurred. CONCLUSIONS: After a median follow-up of 11.8 months, among patients with noncirrhotic chronic PVT without major risk factors for thrombosis, daily rivaroxaban reduced the incidence of venous thromboembolism and did not increase major bleeding events. (Funded by grants from the French Ministry of Health and the Association de Malades des Vaisseaux du foie; ClinicalTrials.gov number, NCT02555111.)

Long-term antithrombotic therapy after venous stent placement

OBJECTIVES

To examine the prescribing patterns and outcomes of antithrombotic regimens after venous stent placement.

METHODS

A total of 87 patients who received inferior vena cava or iliofemoral venous stents were included in the study. A retrospective review was performed to determine the antithrombotic regimens and the subsequent rates of in-stent restenosis, stent thrombosis, and bleeding.

RESULTS

The prescribing patterns of specific antithrombotic regimens were highly variable. In-stent restenosis and stent thrombosis events were observed in 13 of 63 patients (21%) with available follow-up imaging, while major bleeding events were noted in 6 of 87 patients (7%). Triple therapy appeared to reduce the odds of in-stent restenosis/ stent thrombosis when compared to dual antiplatelet therapy (OR = 0.07, P = 0.01).

CONCLUSIONS

Substantial variability exists in antithrombotic therapy following venous stenting at our institution. This study demonstrated a reduction of in-stent restenosis/thrombosis events when utilizing triple therapy compared to antiplatelet-only regimens. However, larger prospective trials are needed to more accurately determine the relative risks and benefits of each antithrombotic regimen.

Joint and soft-tissue injections in rehabilitation inpatients taking direct oral anticoagulants

The risk for complications associated with joint and soft-tissue injections in patients taking direct oral anticoagulants (DOACs) is not fully understood. In this retrospective evaluation of 445 inpatients in a rehabilitation hospital who received corticosteroid injections, complications were compared in patients on DOACs with those who were not. After a review of all injections, no adverse events of significant bleeding (intra-articular or extra-articular) were observed. These findings suggest no substantial increase in adverse events associated with the use of DOACs when performing joint and soft-tissue injection procedures in inpatient rehabilitation setting.

Anticoagulant therapies for acute venous thromboembolism among a cohort of patients discharged from Canadian urban and rural hospitals

OBJECTIVE

To determine anticoagulant therapy at hospital discharge for patients with acute venous thromboembolism (VTE) and secondarily, to describe factors affecting choice of therapy.

DESIGN

A retrospective chart review.

SETTING

Canadian hospitals in Edmonton, Alberta (n=4), Regina, Saskatchewan (n=2) and rural Alberta (n=3) from April 2014 to March 2015.

PARTICIPANTS

All patients discharged with an acute VTE were screened. Those with atypical clots, another indication for anticoagulation, pregnancy/breast feeding or lifespan <3 months were excluded.

PRIMARY AND SECONDARY OUTCOMES

Primarily, we identified the proportion of patients discharged from hospital with acute VTE that were prescribed either traditional therapy (parenteral anticoagulant±warfarin) or a direct oral anticoagulant (DOAC). Secondarily, management based on setting, therapy choice based on deep vein thrombosis (DVT) versus pulmonary embolism (PE), clot burden and renal function was compared. DOAC dosing was assessed (when prescribed), length of hospital stay based on therapy was compared and planned follow-up in the community was described.

RESULTS

Among the 695 patients included, most were discharged following a diagnosis of PE (82.9%) on traditional therapy (parenteral anticoagulant±warfarin) (70.2%) with follow-up by either a family doctor (51.5%) or specialist/clinic (46.9%) postdischarge. Regional variation was most evident between urban and rural sites. Of those prescribed a DOAC (28.3%), the majority were dosed appropriately (85.8%). DOAC use did not differ between those with DVT and PE, was proportionately higher for less severe clots and declined with worsening renal function. Patients prescribed DOACs versus traditional therapy had a shorter length of stay (4 vs 7 days, respectively).

CONCLUSIONS

Uptake of DOAC therapy for acute VTE was modest and may have been influenced by the timing of the audit in relation to the approval of these agents for this indication. Future audits should occur to assess temporal changes and ongoing appropriateness of care delivery.

Use of Direct Oral Anticoagulants in Patients with Cancer: Practical Considerations for the Management of Patients with Nausea or Vomiting

Direct oral anticoagulants (DOACs) have proven efficacy and safety and are approved for use in the prevention and treatment of thromboembolic events in patients with venous thromboembolism (VTE) and those with atrial fibrillation (AF). There is no clear guidance on the use of DOACs in the significant proportion of these patients who have or will develop concomitant cancer. The occurrence of nausea and vomiting in these patients, despite implementation of guideline-recommended antiemetic strategies, is a particular concern because it may affect oral drug intake and consequently outcomes with anticoagulation therapy.Here, we review recent data on the incidence and management of cancer-associated nausea and vomiting and the current evidence and guidance relating to the use of DOACs in patients with cancer. On the basis of this evidence, an international working group of experts in the fields of cancer-associated thrombosis/hemostasis, hematology, and oncology discussed key issues related to the use of DOACs in patients with VTE or AF and cancer who are at risk of nausea and vomiting and developed some consensus recommendations. We present these consensus recommendations, which outline strategies for the use and management of anticoagulants, including DOACs, in patients with VTE or AF and cancer for whom oral drug intake may pose challenges. Guidance is provided on managing patients with gastrointestinal obstruction or nausea and vomiting that is caused by cancer treatments or other cancer-related factors.The recommendations outlined in this review provide a useful reference for health care professionals and will help to improve the management of anticoagulation in patients with VTE or AF and cancer.

IMPLICATIONS FOR PRACTICE

Direct oral anticoagulants (DOACs) offer several advantages over traditional anticoagulants, including ease of administration and the lack of need for routine monitoring. However, the management of patients with an indication for anticoagulation and concomitant cancer, who are at high risk of thromboembolic events, presents several challenges for administering oral therapies, particularly with regard to the risk of nausea and vomiting. In the absence of robust data from randomized trials and specific guidelines, consensus recommendations were developed for healthcare professionals regarding the use of DOACs in patients with cancer, with a focus on the management of patients who are at risk of nausea and vomiting.

Periprocedural Management of Direct Oral Anticoagulants Surrounding Cardioversion and Invasive Electrophysiological Procedures

Supplemental Digital Content is available in the text.

As direct oral anticoagulants (DOACs) have demonstrated favorable efficacy and safety outcomes compared with vitamin K antagonists for the treatment and prevention of venous thromboembolism and the prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, their role in the management of anticoagulation during electrophysiological procedures continues to evolve. At present, guidelines are limited regarding specific recommendations for the use of DOACs in these clinical settings. Here, we review available data regarding the risks and benefits associated with various periprocedural anticoagulation management approaches when patients receiving DOACs undergo electrophysiologic procedures including cardioversion, ablation, and device implantation. This discussion is intended to provide clinicians with an overview of available evidence and best practices to minimize the risk of both thromboembolic and bleeding events in the periprocedural setting.

Safety and timing of resuming dabigatran after major gastrointestinal bleeding reversed by idarucizumab

The recent introduction of direct oral anticoagulants, including rivaroxaban, dabigatran, apixaban, and edoxaban, for the acute treatment and secondary prevention of venous thromboembolism and in atrial fibrillation has been shown to provide greater clinical benefit than oral vitamin K antagonists. However, direct oral anticoagulants are associated with adverse events, the most common being major bleeding; such events require the reversal of the anticoagulant effects by specific agents. In this case report, we describe an 87-year-old female with atrial fibrillation treated with dabigatran who had massive rectal bleeding. Idarucizumab 5 g (2 × 2.5 g/50 mL) was successfully used to reverse dabigatran effect; subsequent to this, treatment with dabigatran was resumed, and there were no further bleeding events. This suggests that dabigatran can be safely restarted after major bleeding, but this outcome needs to be confirmed in studies involving larger groups of patients.

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.

Safety and effectiveness of argatroban versus heparin for preventing venous thromboembolism after lumbar decompressive surgery

BACKGROUND

To evaluate the safety and effectiveness of argatroban for the prevention of venous thromboembolism (VTE) after posterior lumbar decompressive surgery.

METHODS

Included in this retrospective study were 556 patients who underwent posterior lumbar decompressive surgery for trauma and degenerative diseases. They were divided into two groups: argatroban group (n = 274), and low molecular weight heparin (LMWH) group (n = 282). The occurrence of postoperative venous thrombosis and complications including hemorrhage and allergic reaction was compared between the two groups. Neurological and clinical outcomes in terms of Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) were assessed before operation and at 6 and 12 months after operation.

RESULTS

Postoperative venous thromboembolism (VTE) occurred in seven patient. No pulmonary embolism (PE) occurred in any patient. Thrombosis occurred in 3 cases (1.0%) and bleeding in 1 case (0.04%) in argatroban group vs. 4 (1.4%) and 4 (1.4%) in LMWH group, showing no significant between the two groups (P > 0.05). There was significant reduction in the severity of back and leg pain (VAS P < 0.05) and significant improvement in the patient quality of life (ODI, P < 0.05) 6 months and 1 year after operation, showing no significant difference between the two groups (P > 0.05).

CONCLUSIONS

Argatroban proved to be equally effective as LWMH for anticoagulation therapy. Both drugs exhibited a similar preventive effect against postoperative VTE after posterior lumbar spine surgery, without increasing the risk of postoperative bleeding. The neurological and clinical outcomes are satisfactory and similar between the two pharmacological methods.

Apixaban: A Review in Venous Thromboembolism

Apixaban (Eliquis^®) is an oral, direct factor Xa inhibitor that is available for use in the treatment and secondary prevention of venous thromboembolism (VTE). Like other direct oral anticoagulants (DOACs), apixaban has generally predictable pharmacological properties and does not require routine anticoagulation monitoring. In large phase III trials, oral apixaban was noninferior to subcutaneous enoxaparin sodium overlapped with and followed by oral warfarin (enoxaparin/warfarin) in the treatment of adults with acute VTE over 6 months with regard to the incidence of recurrent VTE or VTE-related death (AMPLIFY), and was significantly more effective than placebo in the prevention of recurrent VTE or all-cause mortality over 12 months in patients who had completed 6-12 months' anticoagulation treatment for VTE (AMPLIFY-EXT). Apixaban was generally well tolerated in these trials; the risks of major bleeding and the composite endpoint of major or clinically relevant nonmajor (CRNM) bleeding with apixaban were significantly lower than enoxaparin/warfarin in AMPLIFY and not significantly different from that of placebo in AMPLIFY-EXT. Similarly, in Japanese adults with acute VTE (AMPLIFY-J), apixaban was associated with a significantly lower risk of major or CRNM bleeding than unfractionated heparin plus warfarin, and no cases of recurrent VTE or VTE-related death over 24 weeks. Thus, apixaban is useful therapeutic alternative for the management of adults with VTE.