Extended-duration rivaroxaban thromboprophylaxis in acutely ill medical patients: MAGELLAN study protocol

Apixaban for Extended Thromboprophylaxis After Oncologic Resection: Outcomes and Cost Analysis

BACKGROUND

Patients undergoing oncologic resection are at risk of developing venous thromboembolism (VTE), and this can lead to increased morbidity and hospital costs. Low-molecular weight heparin (LMWH) is recommended as extended thromboprophylaxis (ETP) in high-risk patients and has been shown to reduce rates of VTE.

METHODS

This is a retrospective review of consecutive patients undergoing resection for oncologic indications at a single institution from May 2016 to May 2019. This study evaluated the use of apixaban as ETP at discharge. The primary outcomes were deep vein thrombosis (DVT), pulmonary embolism (PE), or mesenteric/portal venous thromboembolism at 30, 60, and 90 days postoperatively.

RESULTS

A total of 600 patients were included; 449 patients received no ETP, and 151 patients received apixaban. PE occurred in 1.1, 1.6, and 2.3% of patients without ETP and 0, 0, and .7% of patients in the apixaban group (at 30, 60, and 90 days; P = .338, P = .201, and P = .306, respectively). DVT occurred in 1.8, 2.1, and 2.8% of patients without ETP and 0, 0, and 1.4% in the apixaban group (P = .211, P = .121, and P = .535, respectively). The total cost, including ETP and readmission for VTE, per patient was US $5.51 more in the apixaban group.

CONCLUSION

Apixaban therapy for ETP did not produce a statistically significant reduction in VTE events in our patients. Future studies should include more patients in a prospective multicenter trial.

Thromboprophylaxis and clinical outcomes in moderate COVID-19 patients: A comparative study

Background

Many thrombotic complications are linked to coronavirus disease 2019 (COVID-19). Antithrombotic treatments are important for prophylaxis against these thrombotic events.

Objectives

This study was designed to compare enoxaparin and rivaroxaban as prophylactic anticoagulants in moderate cases of COVID-19 in terms of efficacy, safety, and clinical outcomes.

Methods

The study involved 124 patients with moderate COVID-19 (pneumonia without hypoxia) divided into two groups. The first group (G1) comprised 66 patients who received enoxaparin subcutaneously at a dose of 0.5 mg/kg every 12 h until discharge from the hospital. The second group (G2) comprised 58 patients who received oral rivaroxaban at a dose of 10 mg once daily until discharge from the hospital. The outcomes evaluated in this study were as follows: intermediate care unit (IMCU) duration, the number of patients transferred from the IMCU to the intensive care unit (ICU), ICU duration, the total length of hospital stay, in-hospital mortality, and thrombotic and bleeding complications.

Results

No significant differences in IMCU duration (p = 0.39), ICU duration (p = 0.96), and total length of hospital stay (p = 0.73) were observed between the two groups. The percentage of patients requiring ICU admission after hospitalization was 21.2% in G1 and 22.4% in G2 (p = 0.87). The mortality rate was 12.1% in G1 and 10.3% in G2 (p = 0.76). The proportion of patients who had thrombotic complications was 9.1% in G1 and 12.1% in G2 (p = 0.59). The incidence of mild bleeding was 3% in G1 and 1.7% in G2 (p = 0.64).

Conclusion

Either enoxaparin or rivaroxaban may be used as thromboprophylaxis agents in managing patients with moderate COVID-19. Either medication has no clear advantage over the other.

Association of Bleeding Severity with Mortality in Extended Thromboprophylaxis of Medically Ill Patients in the MAGELLAN and MARINER Trials

Background: Extended thromboprophylaxis has not been widely implemented in acutely ill medical patients due to bleeding concerns. The MAGELLAN and MARINER trials evaluated whether rivaroxaban compared with enoxaparin or placebo could prevent venous thromboembolism (VTE) without increased bleeding. We hypothesized that patients with major bleeding (MB) but not those with non-major clinically relevant bleeding (NMCRB), would be at an increased risk of all-cause mortality (ACM). Methods: We evaluated all bleeding events in patients taking at least one dose of study drug and their association with ACM in 4 mutually exclusive groups: (1) no bleeding, or first event was (2) NMCRB, (3) MB, or (4) trivial bleeding. Using a Cox proportional hazards model adjusted for differences in baseline characteristics associated with ACM, we assessed the risk of ACM after such events. Results: Compared to patients with no bleeding, the risk of ACM for patients with NMCRB was not increased in MARINER (HR 0.43, p=0.235) but was increased in MAGELLAN (HR 1.74 p=0.021). MB was associated with a higher incidence of ACM in both studies, while trivial bleeding was not associated with ACM in either study. Conclusions: Patients with MB had an increased risk of ACM, while NMCRB was not consistently associated with an increased risk of death. These results inform the risk-benefit calculus of extended thromboprophylaxis in medically ill patients.

Desafios da profilaxia estendida do tromboembolismo venoso em pacientes clínicos e cirúrgicos

Patients hospitalized for acute medical and surgical illnesses are at risk of developing venous thromboembolism (VTE) during hospitalization and after discharge. Extended pharmacological prophylaxis beyond the hospital stay is recommended for patients undergoing surgeries at high risk for VTE and for selected groups of hospitalized medical patients. This practice involves several challenges, from identification of at-risk populations eligible for extended prophylaxis to choice of the most appropriate anticoagulant and definition of the ideal duration of use. This review will present the main VTE risk assessment models for hospitalized medical and surgical patients, the current recommendations for use of extended prophylaxis, and its limitations and benefits.

Challenges of extended venous thromboembolism prophylaxis in medical and surgical patients

Abstract Patients hospitalized for acute medical and surgical illnesses are at risk of developing venous thromboembolism (VTE) during hospitalization and after discharge. Extended pharmacological prophylaxis beyond the hospital stay is recommended for patients undergoing surgeries at high risk for VTE and for selected groups of hospitalized medical patients. This practice involves several challenges, from identification of at-risk populations eligible for extended prophylaxis to choice of the most appropriate anticoagulant and definition of the ideal duration of use. This review will present the main VTE risk assessment models for hospitalized medical and surgical patients, the current recommendations for use of extended prophylaxis, and its limitations and benefits.

Antithrombotic Stewardship: Assessing Use of Computerized Clinical Decision Support Tools to Enhance Safe Prescribing of Direct Oral Anticoagulants in Hospitalized Patients

ABSTRACT

Prescribing patterns for oral anticoagulants in patients with nonvalvular atrial fibrillation and venous thromboembolism is shifting from vitamin K antagonists, such as warfarin to the direct oral anticoagulants (DOACs), such as dabigatran, rivaroxaban, and apixaban. Although many hospital systems have implemented clinical decision support or enhanced monitoring for patients prescribed warfarin, there is limited evidence to suggest similar levels of enhanced monitoring for DOACs. The antithrombotic stewardship team at our institution developed guidelines and implemented computerized clinical decision support (CCDS) tools to enhance medication and patient safety related to the DOACs. We sought to assess the safety and effectiveness of these CCDS tools available to clinicians upon DOAC prescription in hospitalized patients. We performed a retrospective review of 121 patients who received at least two doses of a DOAC from January 2013 to July 2014. We assessed dosing of the DOAC according to the CCDS provided upon order entry. Adherence to CCDS was 80% (n = 24), 75% (n = 46), and 87% (n = 27) in the dabigatran, apixaban, and rivaroxaban group, respectively. Our data demonstrate that implementing CCDS for DOACs into the electronic medical record may ensure safe prescribing of high-risk medications.

Risk of Severe Bleeding With Extended Rivaroxaban to Prevent Venous Thromboembolism in Acute Medically Ill Patients With Bronchiectasis

Background: Bronchiectasis is a chronic inflammation of the bronchi with recurrent infections and hemoptysis. The MAGELLAN study compared oral rivaroxaban, 10 mg once daily (QD), for 35 ± 4 days with subcutaneous enoxaparin 40 mg QD for 10 ± 4 days followed by placebo for 25 ± 4 days to prevent venous thromboembolism in patients hospitalized with an acute medical illness. MAGELLAN included a subset of patients with bronchiectasis. In a post hoc analysis, we evaluated the incidence and severity of pulmonary bleeding in patients with bronchiectasis who were hospitalized for an acute medical illness. This analysis included MAGELLAN patients diagnosed with bronchiectasis at baseline. Patients were evaluated by treatment group for International Society on Thrombosis and Haemostasis major bleeding, non-major clinically relevant (NMCR) bleeding, and the composite of the 2 (ie, clinically relevant bleeding). Results: Medically ill patients with bronchiectasis were randomized to rivaroxaban (n = 60) or enoxaparin/placebo (n = 61). There were 2 fatal pulmonary bleeds and 1 fatal gastrointestinal bleed in the rivaroxaban arm and no fatal or major bleeding in the enoxaparin/placebo arm. The incidence of major bleeding was 5% in the rivaroxaban arm. One NMCR bleed occurred in the rivaroxaban arm and 2 NMCR bleeds occurred in the enoxaparin/placebo arm. The incidence of clinically relevant bleeding was 6.7% versus 3.3% in the rivaroxaban and enoxaparin/placebo groups, respectively (relative risk = 2.06 [95% confidence interval: 0.351-12.046]). Conclusion: In-patients hospitalized with bronchiectasis and an acute medical illness, clinically relevant bleeding, including fatal pulmonary hemorrhage, occurs more frequently with extended rivaroxaban thromboprophylaxis than with enoxaparin followed by placebo.

Current Opinion on the use of Direct Oral Anticoagulants for the Prophylaxis of Venous Thromboembolism among Medical Inpatients

Venous thromboembolism (VTE) is a known cause of morbidity and mortality, especially among acutely ill medical patients. Although VTE prophylaxis is part of post-discharge clinical care in surgical patients, there is controversy regarding its use in acutely ill medical patients and the current guideline statements suggest against its routine use. Recent clinical trials (APEX, MAGELLAN and MARINER) compared the safety and efficacy of direct oral anticoagulants (including betrixaban and rivaroxaban) with the standard of the care, enoxaparin, to identify the risk–benefit tradeoff. In this review, we summarized the key findings from these trials and substudies and recent updates in society guidelines regarding VTE prevention. In addition, we discussed the potential barriers, cost-effectiveness, and COVID-19 with respect to the implementation of extended-duration or post-discharge usage of direct oral anticoagulants.

Association Between Asymptomatic Proximal Deep Vein Thrombosis and Mortality in Acutely Ill Medical Patients

Background Asymptomatic proximal deep vein thrombosis (DVT) is an end point frequently used to evaluate the efficacy of anticoagulant thromboprophylaxis in medical patients. Recently, the clinical relevance of asymptomatic DVT has been challenged. Methods and Results The objective of this study was to evaluate the relationship between asymptomatic proximal DVT and all-cause mortality (ACM) using a cohort analysis of a randomized trial for the prevention of venous thromboembolism (VTE) in acutely ill medical patients. Patients who received at least 1 dose of study drug and had an adequate compression ultrasound examination of the legs on either day 10 or day 35 were categorized into 1 of 3 cohorts: no VTE, asymptomatic proximal DVT, or symptomatic DVT. Cox proportional hazards model, with adjustment for significant independent predictors of mortality, were used to compare the incidences of ACM. Of the 7036 patients, 6776 had no VTE, 236 had asymptomatic DVT, and 24 had symptomatic VTE. The incidence of ACM was 4.8% in patients without VTE. Both asymptomatic proximal DVT (mortality, 11.4%; hazard ratio [HR], 2.31; 95% CI, 1.52-3.51; P<0.0001) and symptomatic VTE (mortality, 29.2%; HR, 9.42; 95% CI, 4.18-21.20; P<0.0001) were independently associated with significant increases in ACM. The analysis was post hoc, and ultrasound results were not available for all patients. Adjustment for baseline variables significantly associated with ACM may not fully compensate for differences. Conclusions Asymptomatic proximal DVT is associated with higher ACM than no VTE and remains a relevant end point to evaluate the efficacy of anticoagulant thromboprophylaxis in medical patients. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00571649.

Improved Benefit Risk Profile of Rivaroxaban in a Subpopulation of the MAGELLAN Study

Acutely ill medical patients are at risk of venous thromboembolism (VTE) and VTE-related mortality during hospitalization and posthospital discharge, but widespread adoption of extended thromboprophylaxis has not occurred. We analyzed a subpopulation within the MAGELLAN study of extended thromboprophylaxis with rivaroxaban to reevaluate the benefit risk profile. We identified 5 risk factors for major and fatal bleeding after a clinical analysis of the MAGELLAN study and analyzed efficacy and safety with these patients excluded (n = 1551). Risk factors included: active cancer, dual antiplatelet therapy at baseline, bronchiectasis/pulmonary cavitation, gastroduodenal ulcer, or bleeding within 3 months before randomization. We evaluated efficacy, safety, and benefit risk using clinically comparable endpoints in the subpopulation. At day 10, rivaroxaban was noninferior to enoxaparin (relative risk [RR] = 0.82, 95% confidence interval [CI] = 0.58-1.15) and at day 35 rivaroxaban was significantly better than enoxaparin/placebo (RR = 0.68, 95% CI = 0.53-0.88) in reducing VTE and VTE-related death. Major bleeding was reduced at day 10 (RR = 2.18, 95% CI = 1.07-4.44 vs 1.19, 95% CI = 0.54-2.65) and at day 35 (2.87, 95% CI = 1.60-5.15 vs 1.48, 95% CI = 0.77-2.84) for MAGELLAN versus this subpopulation, respectively. The benefit risk profile was favorable in this subpopulation treated for 35 days, with the number needed to treat ranging from 55 to 481 and number needed to harm from 455 to 1067 for all pairwise evaluations. Five exclusionary criteria defined a subpopulation of acutely ill medical patients with a positive benefit risk profile for in-hospital and extended thromboprophylaxis with rivaroxaban.

Modified IMPROVE VTE Risk Score and Elevated D-Dimer Identify a High Venous Thromboembolism Risk in Acutely Ill Medical Population for Extended Thromboprophylaxis

An individualized approach to identify acutely ill medical patients at increased risk of venous thromboembolism (VTE) and a low risk of bleeding to optimize the benefit and risk of extended thromboprophylaxis (ET) is needed. The International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE risk score has undergone extensive external validation in medically ill patients for in-hospital use and a modified model was used in the MARINER trial of ET also incorporating an elevated D-dimer. The MAGELLAN study demonstrated efficacy with rivaroxaban but had excess bleeding. This retrospective analysis investigated whether the modified IMPROVE VTE model with an elevated D-dimer could identify a high VTE risk subgroup of patients for ET from a subpopulation of the MAGELLAN study, which was previously identified as having a lower risk of bleeding. We incorporated the modified IMPROVE VTE score using a cutoff score of 4 or more or 2 and 3 with an elevated D-dimer (>2 times the upper limit of normal) to the MAGELLAN subpopulation. In total, 56% of the patients met the high-risk criteria. In the placebo group, the total VTE event rate at Day 35 was 7.94% in the high-risk group and 2.83% for patients in the lower-risk group. A reduction in VTE was observed with rivaroxaban in the high-risk group (relative risk [RR]: 0.68, 95% confidence interval [CI]: 0.51-0.91, p  = 0.008) and in the lower-risk group (RR: 0.69, 95% CI: 0.40 -1.20, p  = 0.187). The modified IMPROVE VTE score with an elevated D-dimer identified a nearly threefold higher VTE risk subpopulation of patients where a significant benefit exists for ET using rivaroxaban.

Role of ambulation to prevent venous thromboembolism in medical patients: where do we stand?

Venous thromboembolism (VTE) encompasses the spectrum of manifestations of deep venous thrombosis and/or pulmonary embolism and is a common, serious, and preventable complication in hospitalized patients. Although immobility plays an important role in determining VTE risk in medical patients, no clear and uniform criteria exist to guide clinicians in assessing immobility. The variation in the descriptions that do exist makes it difficult to interpret and compare the results of randomized clinical trials with respect to the influence of different levels of immobility on the magnitude of VTE risk and the role that early ambulation as an isolated factor plays in prevention of such events. Understanding these limitations is a prerequisite for the proper use and interpretation of VTE risk assessment tools and for indicating the best strategy for preventing venous thrombosis in hospitalized medical patients. The objective of this study was to review the main evidence reported in the literature on the role of ambulation in prevention of VTE.

What has changed in venous thromboembolism prophylaxis for hospitalized patients over recent decades: review article

Venous thromboembolism (VTE) is a common disease with high rates of morbidity and mortality and is considered the number one cause of avoidable mortality among hospitalized patients. Although VTE incidence is extremely high in all countries and there is ample evidence that thromboprophylaxis inexpensively reduces the rate of thromboembolic complications in both clinical and surgical patients, a great deal of doubt remains with respect to patient safety with this type of intervention and in relation to the ideal thromboprophylaxis methods. Countless studies and evidence-based recommendations confirm the efficacy of prophylaxis for prevention of VTE and/or patient deaths, but it remains underutilized to this day. This article presents a wide-ranging review of existing prophylaxis methods up to the present, from guidelines and national and international studies of thromboprophylaxis.

Rivaroxaban for thromboprophylaxis among patients recently hospitalized for acute infectious diseases: a subgroup analysis of the MAGELLAN study

Essentials Net benefit of venous thromboprophylaxis (VTE) in patients hospitalized for infections is unknown. MAGELLAN trial subgroup analysis was performed for patients hospitalized for acute infectious diseases. At day 35, prolonged rivaroxaban prophylaxis reduced VTE compared to enoxaparin (4.2% vs. 6.6%). Rivaroxaban prophylaxis reduced VTE in patients hospitalized for active lung infections.

SUMMARY

Background Despite the well-established association between infection and venous thromboembolism (VTE), there are few data specifically assessing the efficacy and safety of the VTE prophylaxis strategies for patients hospitalized for acute infectious diseases. Objectives To estimate the incidence of VTE and bleeding outcomes, comparing prolonged prophylaxis with rivaroxaban 10 mg daily for 35 days with enoxaparin 40 mg daily for 10 days. Patients/Methods A subgroup analysis of patients hospitalized for acute infectious diseases in the MAGELLAN trial was performed. The primary efficacy outcome was the composite of asymptomatic proximal or symptomatic VTE at days 10 and 35. The principal safety outcome was the composite of major or clinically relevant non-major bleeding. Results Three thousand one hundred and seventy-three patients with acute infectious diseases leading to hospitalization were randomized to either rivaroxaban (n = 1585) or enoxaparin/placebo (n = 1588), and received at least one dose of study medication. At day 10, primary composite efficacy outcomes did not differ between prophylaxis strategies (rivaroxaban, 2.7%; and enoxaparin, 3.7%). At day 35, there were fewer VTE events with rivaroxaban (4.2%) than with enoxaparin (6.6%) (relative risk [RR] 0.64; 95% confidence interval [CI] 0.45-0.92). Patients with pulmonary infections randomized to rivaroxaban had a lower incidence of VTE both at 10 days (RR 0.50, 95% CI 0.28-0.90) and at 35 days (RR 0.54, 95% CI 0.33-0.87). Primary safety outcome events were increased with rivaroxaban (RR 2.42, 95% CI 1.60-3.66). Conclusions Prolonged rivaroxaban prophylaxis reduced the incidence of VTE in patients hospitalized for acute infectious diseases, particularly those involving the lungs. Efficacy benefits were, in part, offset by bleeding outcomes. ClinicalTrials.gov Number: NCT 00571649.

New Trends in Anticoagulation Therapy

Anticoagulation pharmacy has been dramatically altered with US Food and Drug Administration (FDA) approval of 5 direct oral anticoagulants, 1 novel reversal agent and, a second designated for fast-track approval. Trial data surrounding current trends in anticoagulant choice for VTE, reversal, and bridging are constantly redefining practice. Extended therapy for unprovoked VTE has expanded to include low-dose direct oral anticoagulants, aspirin, and the use of the HERDOO2 system to identify women who can stop anticoagulant therapy without increased risk of recurrent VTE. Trends in thromboprophylaxis include extended duration low-dose direct oral anticoagulants to prevent VTE in high-risk patients.

Direct oral anticoagulants: now also for prevention and treatment of cancer-associated venous thromboembolism?

Data on specific studies in cancer patients using direct oral anticoagulants (DOACs) for the prevention and treatment of venous thromboembolism (VTE) are still scarce. For preventing VTE with DOACs, current experience is still very limited, so definite conclusions cannot yet be drawn. However, DOACs have so far been compared with vitamin K antagonists (VKAs) in patients with acute VTE in 5 studies, and several hundreds of patients included in these studies had either active cancer, a history of cancer, or a new occurrence of cancer during the course of disease. Meta-analyses have revealed an at least similar efficacy and safety profile of DOACs compared with VKAs. A number of studies of cancer patients investigating primary prevention and treatment are underway, and some will be finalized soon. Nevertheless, we might need further trials, specifically on the prevention of VTE in patients who are at particularly high risk. This article also includes a personal opinion on the use of DOACs in cancer patients. In conclusion, the currently available data show that DOACs might be safe and efficacious in the treatment of VTE, however, this has yet to be proven in specifically designed trials in patients with cancer. With regard to prevention, thus far, even less data exist, and the outcomes of the ongoing studies have to be evaluated before DOACs may be used for primary prevention.

Extended thromboprophylaxis in the acutely ill medical patient after hospitalization - a paradigm shift in post-discharge thromboprophylaxis

Venous thromboembolism (VTE) is a significant healthcare burden with approximately 900,000 events annually in the United States, over half of which are healthcare-associated. This number is anticipated to double by 2050. Group prophylaxis strategies confined to the inpatient setting appear to have minimal impact on the reduction of post-discharge VTE in medically ill patients due to shortened lengths of stay and a heterogenous population that includes patients at low risk for VTE. In accordance with current guideline recommendations, very few (<5%) medically ill patients are discharged with extended prophylaxis, which potentially creates a clinical gap for at-risk patients as VTE risk has been shown to persist for up to 90 days. Initial studies of extended thromboprophylaxis in acutely ill medical patients with enoxaparin, rivaroxaban and apixaban showed little to no benefit towards VTE reduction that was consistently outweighed by increased bleeding. The more recent APEX study that compared betrixaban to enoxaparin in an enriched patient population at high-risk for VTE was the first study of extended thromboprophylaxis that showed similar efficacy in VTE prevention without an increase in major bleeding. Based on the APEX results, betrixaban recently gained FDA approval for extended thromboprophylaxis in acutely ill medical patients. Recognition that up to half of medically ill patients are not at sufficient risk to warrant thromboprophylaxis has driven extensive research towards development of scientifically derived and validated VTE risk assessment models intended to identify patients who do not warrant prophylaxis, as well as those at high risk who may derive benefit from extended thromboprophylaxis. This article will review prior and ongoing extended thromboprophylaxis studies, VTE and bleed risk assessment models, incorporation of biomarkers in VTE risk assessment and key issues in the paradigm shift towards individualized VTE prophylaxis in acutely ill medical patients.

Impact of age on the efficacy and safety of extended-duration thromboprophylaxis in medical patients

The EXCLAIM study enrolled hospitalised acutely ill medical patients with age >40 years and recently-reduced mobility into a trial of extended-duration anticoagulant thromboprophylaxis. This post-hoc analysis evaluated the impact of age on patient outcomes. After completion of open-label therapy with enoxaparin 40 mg once-daily (10 ± 4 days), eligible patients underwent randomisation to receive double-blind therapy of enoxaparin (n=2,975) or placebo (n=2,988) for 28 ± 4 days. During follow-up, the venous thromboembolism (VTE) risk increased with age in both treatment groups. In patients with age >75 years, those who received extended-duration enoxaparin had lower incidence of VTE (2.5% vs 6.7%; absolute difference [AD] [95% confidence interval]: −4.2% [−6.5, −2.0]), proximal deep-vein thrombosis (2.5% vs 6.6%; AD −4.1 % [−6.2, −2.0]), and symptomatic VTE (0.3% vs 1.5%; AD −1.2% [−2.2, −0.3]), in comparison to those who received placebo. In patients with age ≤75 years, those who received enoxaparin had reduced VTE (2.4% vs 2.8%; AD −0.4% [−1.5, 0.7]) and symptomatic VTE (0.2% vs 0.7%; AD −0.6% [−1.0, −0.1]) in comparison to those who received placebo. In both age subgroups, patients who received enoxaparin had increased rates of major bleeding versus those who received placebo: age >75 years (0.6% vs 0.2%; AD +0.3% [−0.2, 0.9], respectively); age ≤75 years (0.7% vs 0.2%; AD +0.5% [0.1, 0.9]). Patients in both age subgroups that received enoxaparin had similar low bleeding rates (0.6% and 0.7%, respectively). VTE risk increased with age, though the bleeding risk did not. Patients with age >75 years had a more favourable benefit-to-harm profile than younger patients.

The use of rivaroxaban for short- and long-term treatment of venous thromboembolism

Venous thromboembolism (VTE) is a major healthcare concern and affects more than 1.6 million individuals each year worldwide. Long-term complications include recurrent VTE, chronic thromboembolic pulmonary hypertension and post-thrombotic syndrome. Rivaroxaban is an oral, direct factor Xa inhibitor that has advantages over traditional VTE therapies, including minimal drug and food interactions and no requirement for routine coagulation monitoring. It is currently approved for VTE prevention in adult patients undergoing elective hip or knee replacement surgery. This review evaluates the potential clinical implications of the multicentre, randomised EINSTEIN studies (EINSTEIN DVT and EINSTEIN EXT), which investigated rivaroxaban for the treatment and prevention of recurrent VTE. In EINSTEIN DVT, rivaroxaban was non-inferior to the standard of care (enoxaparin plus a vitamin K antagonist) for recurrent VTE in patients with acute deep-vein thrombosis (DVT) without pulmonary embolism (PE). In EINSTEIN EXT, extended-duration rivaroxaban had superior efficacy to placebo in patients with confirmed DVT or PE who had received 6–12 months of prior VTE treatment. Rivaroxaban was associated with an acceptable safety profile in both studies. The net clinical benefit (efficacy and safety end-points combined) of rivaroxaban was significantly greater than its comparators. The EINSTEIN studies are the first demonstration that a single drug - rivaroxaban - can be effective for both the initial treatment of DVT and prevention of recurrent VTE. Moreover, the simple, once-daily oral administration of rivaroxaban could potentially improve adherence to extended-duration VTE treatment compared with the current standard of care in individuals with confirmed DVT or PE.

VTE primary prevention, including hospitalised medical and orthopaedic surgical patients

Primary prevention is the key to managing a significant proportion of the burden of venous thromboembolism (VTE), defined as deep venous thrombosis (DVT) or pulmonary embolism (PE). This is because VTE may lead to sudden death or are often misdiagnosed and therefore treatment is not feasible. Primary prevention usually commences in hospital as VTE following hospitalisation adds to the significant disease burden worldwide. Numerous medical, surgical and other risk factors have been recognised and studied as indications for prophylaxis. The risk of VTE continues following admission to hospital with a medical or surgical condition, usually long after discharge and therefore prolonged primary prophylaxis is often recommended. Clinical and observational studies in surgical patients show this risk extends for months and perhaps more than one year, for medical patients the risk extends for at least several weeks. For the specific groups of patients at higher risk of developing VTE primary prevention, either pharmaceutical or mechanical, is recommended. The aim of this review is to describe the population at risk, the main related risk factors and the approach to thromboprophylaxis in different populations.

Effect of Huisheng oral solution on coagulation function in perioperative period in patients with primary lung cancer

BACKGROUND

The incidence of venous thromboembolism (VTE) is about 4-10% in lung cancer patients. Huisheng oral solution (HSOS) has been previously demonstrated to inhibit carageenan induced acute thrombosis in rats, reduce the incidence of thrombosis in the lungs and mesentery of tumor-bearing mice and inhibit tumor cell metastasis. The purpose of this study was to assess the anticoagulant effect of HSOS in lung cancer patients in the perioperative period.

METHODS

This study was a multicenter, randomized, single-blind, blank-controlled clinical trial. A total of patients at five hospitals in Hebei Province, China were included. The patients were randomly divided into study group or control group according to random number table. The primary outcome was the blood test indices in both groups. The study group was given oral HSOS (20 mL, bid) from admission until 24 h before surgery. If no active bleeding was observed, the patients were given oral HSOS (20 mL, tid) from 24 h to 24 d postoperatively. The patients in the study group did not receive any other anticoagulation therapy during the study period and the control group only underwent surgery. The study protocol was approved by the local ethics committee of principal investigator hospital. Blood samples were taken at admission (before therapy), 24 h, 72 h, 10 d (before discharge) and 24 d (first visit after discharge) after surgery. Routine blood tests [red blood cell (RBC) count, white blood cell (WBC) count, hemoglobin (HGB), and platelet (PLT) count] and coagulation function test [prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), and plasma D-dimer] were performed. The changes in outcome measures over time were analyzed by repeated measures analysis of variance to compare the differences between groups and between different time points and assess the impact of tumor stage and mode of surgery on them. All tests were two-tailed, and P values <0.05 were considered statistically significant.

RESULTS

The results differed between different tumor stage groups. In stage III-IV group, there was no significant difference in various indices between the study group and control group. In stage I-II group, there was significant difference in hemoglobin (P=0.004), platelet count (P=0.007), fibrinogen (P=0.046), and plasma D-dimer (24 d: P=0.032) between two groups. Fibrinogen reach the peak 72 h after surgery, and other indices reach the peak 7-10 d postoperatively and declined one month after surgery, and the decline tendency was different between two groups. In addition, no adverse drug reaction was observed in both the study group and control group.

CONCLUSIONS

HSOS (20 mL, tid) is of good safety profile and does not increase the risk of bleeding. With its unique characteristic of convenience for being taken, HSOS (20 mL, tid) could be a proper treatment for lung cancer patients in the perioperative period.

Variation in Definitions of Immobility in Pharmacological Thromboprophylaxis Clinical Trials in Medical Inpatients: A Systematic Review

BACKGROUND

Although immobility is a common risk factor for venous thromboembolism (VTE) in medical inpatients, lack of a consistent definition of this term may limit accurate assessment of VTE risk for thromboprophylaxis.

OBJECTIVE

To examine various definitions of immobility used in recent pharmacological thromboprophylaxis clinical trials.

DATA SOURCES

PubMed and relevant references from articles/reviews from 2008 to 2016 were searched. Randomized controlled trials (RCTs) and other clinical studies involving adult hospitalized medical patients in acute care hospital settings that used the term immobility were selected. Two investigators independently abstracted data in duplicate, and accuracy was checked by a third investigator.

RESULTS

Twenty-one clinical studies were included. There was heterogeneity among individual VTE risk factors, with respect to the definition of immobility in medical inpatients in these trials. Thirteen studies utilized objective criteria to define "immobility" including duration (12 studies) and distance or time walked (6 studies). In contrast, 7 studies focused principally on subjective definitions (ie, describing the nature of immobility rather than specifying its quantitative measurement). Three RCTs vaguely defined the level of patient's immobility after hospitalization.

CONCLUSION

Despite the well-known effectiveness of pharmacological thromboprophylaxis for the prevention of VTE in acutely ill medical patients, there is no current consensus on how to define immobility. The heterogeneous nature of definitions of immobility has led to uncertainty about the importance of immobility in VTE risk assessment models. Although clinical studies have incorporated varying definitions of immobility into their inclusion criteria, immobility as a specific VTE risk factor has not been clearly defined.

Randomized Phase III Trial of Standard Therapy Plus Low Molecular Weight Heparin in Patients With Lung Cancer: FRAGMATIC Trial

PURPOSE

Venous thromboembolism (VTE) is common in cancer patients. Evidence has suggested that low molecular weight heparin (LMWH) might improve survival in patients with cancer by preventing both VTE and the progression of metastases. No trial in a single cancer type has been powered to demonstrate a clinically significant survival difference. The aim of this trial was to investigate this question in patients with lung cancer.

PATIENTS AND METHODS

We conducted a multicenter, open-label, randomized trial to evaluate the addition of a primary prophylactic dose of LMWH for 24 weeks to standard treatment in patients with newly diagnosed lung cancer of any stage and histology. The primary outcome was 1-year survival. Secondary outcomes included metastasis-free survival, VTE-free survival, toxicity, and quality of life.

RESULTS

For this trial, 2,202 patients were randomly assigned to the two treatment arms over 4 years. The trial did not reach its intended number of events for the primary analysis (2,047 deaths), and data were analyzed after 2,013 deaths after discussion with the independent data monitoring committee. There was no evidence of a difference in overall or metastasis-free survival between the two arms (hazard ratio [HR], 1.01; 95% CI, 0.93 to 1.10; P = .814; and HR, 0.99; 95% CI, 0.91 to 1.08; P = .864, respectively). There was a reduction in the risk of VTE from 9.7% to 5.5% (HR, 0.57; 95% CI, 0.42 to 0.79; P = .001) in the LMWH arm and no difference in major bleeding events but evidence of an increase in the composite of major and clinically relevant nonmajor bleeding in the LMWH arm.

CONCLUSION

LMWH did not improve overall survival in the patients with lung cancer in this trial. A significant reduction in VTE is associated with an increase in clinically relevant nonmajor bleeding. Strategies to target those at greatest risk of VTE are warranted.

The Role of New Oral Anticoagulants (NOACs) in Cancer Patients

New oral anticoagulants (NOACs) are likely to have a major impact in the next few years, changing clinical practice of anticoagulation therapy. Evidence on its efficacy and superiority to vitamin K antagonists (VKAs) in treating non-cancer patients have been reported in a few clinical trials. However, patients with cancer are complicated by the prothrombotic nature of the disease, need for potentially invasive surgery and interventions, and altered drug handling. This chapter examines the available evidence and guidelines on the use of NOAC in patients with cancer.

Clinical development of rivaroxaban: emerging new clinical evidences?

Rivaroxaban has proven efficacious in a variety of conditions. In fact, rivaroxaban has been approved for the prevention of venous thromboembolism after elective hip or knee replacement surgery, for the prevention and treatment of deep vein thrombosis and pulmonary embolism, for the prevention of stroke in patients with nonvalvular atrial fibrillation and for the prevention of atherothrombotic events after acute coronary syndrome with elevated cardiac biomarkers. However, clinical development of rivaroxaban is ongoing. Considering published and on-going randomized clinical trials, noninterventional studies and registries, over 275,000 patients are being analyzed. The aim of this review was to update the clinical development of rivaroxaban, including completed and ongoing studies not only randomized clinical trials, but also clinical practice studies.

Overview of the new oral anticoagulants: opportunities and challenges

The non-vitamin K antagonist oral anticoagulants (NOACs) are replacing warfarin for many indications. These agents include dabigatran, which inhibits thrombin, and rivaroxaban, apixaban, and edoxaban, which inhibit factor Xa. All 4 agents are licensed in the United States for stroke prevention in atrial fibrillation and for treatment of venous thromboembolism and rivaroxaban and apixaban are approved for thromboprophylaxis after elective hip or knee arthroplasty. The NOACs are at least as effective as warfarin, but are not only more convenient to administer because they can be given in fixed doses without routine coagulation monitoring but also are safer because they are associated with less intracranial bleeding. As part of a theme series on the NOACs, this article (1) compares the pharmacological profiles of the NOACs with that of warfarin, (2) identifies the doses of the NOACs for each approved indication, (3) provides an overview of the completed phase III trials with the NOACs, (4) briefly discusses the ongoing studies with the NOACs for new indications, (5) reviews the emerging real-world data with the NOACs, and (6) highlights the potential opportunities for the NOACs and identifies the remaining challenges.

Rivaroxaban in the Treatment of Venous Thromboembolism and the Prevention of Recurrences

Anticoagulation therapy is the standard treatment of patients with symptomatic venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism. Until recently, treatment of VTE was based on parenteral or low-molecular-weight heparin for initial therapy (5-10 days) and oral vitamin K antagonists for long-term therapy. Those treatments have some limitations, including parenteral administration (heparins), the need for frequent monitoring and dose adjustments, interactions with several medications, and dietary restrictions (vitamin K antagonists). Rivaroxaban is a new oral direct factor Xa inhibitor with a wide therapeutic window, predictable anticoagulant effect, no food interactions, and few drug interactions. Consequently, no periodic monitoring of anticoagulation is needed, and fixed doses can be prescribed. EINSTEIN program demonstrated that rivaroxaban was as effective as and significantly safer than standard therapy for treatment of VTE. Rivaroxaban was recently authorized so doubts exist about how to use it in daily clinical practice. This document aims to clarify common questions formulated by clinicians regarding the use of this new drug.

Predicting the risk of venous thromboembolism in patients hospitalized with heart failure

BACKGROUND

Whether heart failure (HF) increases the risk of venous thromboembolism (VTE) is not well established. In the phase III MAGELLAN (Multicenter, rAndomized, parallel Group Efficacy and safety study for the prevention of venous thromboembolism in hospitalized medically iLL patients comparing rivaroxabAN with enoxaparin) trial, extended-duration rivaroxaban was compared with standard-duration enoxaparin followed by placebo for VTE prevention in 8101 hospitalized acutely ill patients with or without HF. The aim of this analysis was to evaluate the relationship between HF severity and the risk of VTE in MAGELLAN patients.

METHODS AND RESULTS

Hospitalized patients diagnosed with HF were included according to New York Heart Association class III or IV at admission (n=2593). HF severity was determined by N-terminal probrain natriuretic peptide (NT-proBNP) plasma concentrations (median 1904 pg/mL). Baseline plasma D-dimer concentrations ranged from 0.6 to 1.7 μg/L for the less and more severe HF subgroups. Patients with more severe HF had a greater incidence of VTE versus patients with less severe HF, with a significant trend up to Day 10 (4.3% versus 2.2%; P=0.0108) and Day 35 (7.2% versus 4.1%; P=0.0150). Multivariable analysis confirmed that NT-proBNP concentration was associated with VTE risk up to Day 10 (P=0.017) and D-dimer concentration with VTE risk up to Day 35 (P=0.005). The association between VTE risk and HF severity that was observed in the enoxaparin/placebo group was not seen in the extended-duration rivaroxaban group.

CONCLUSIONS

Patients with more severe HF, as defined by high NT-proBNP plasma concentration, were at increased risk of VTE. NT-proBNP may be useful to identify high short-term risk, whereas elevated D-dimer may be suggestive of high midterm risk.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00571649.

D-dimer as a predictor of venous thromboembolism in acutely ill, hospitalized patients: a subanalysis of the randomized controlled MAGELLAN trial

BACKGROUND

D-dimer concentrations have not been evaluated extensively as a predictor of increased venous thromboembolism (VTE) risk in acutely ill, hospitalized medical patients.

OBJECTIVES

To analyze the relationships between D-dimer concentration, VTE and bleeding in the MAGELLAN trial (NCT00571649).

PATIENTS/METHODS

This was a multicenter, randomized, controlled trial. Patients aged ≥ 40 years, hospitalized for acute medical illnesses with risk factors for VTE received subcutaneous enoxaparin 40 mg once daily for 10 ± 4 days then placebo up to day 35, or oral rivaroxaban 10 mg once daily for 35 ± 4 days. Patients (n = 7581) were grouped by baseline D-dimer ≤ 2 × or > 2 × the upper limit of normal. VTE and major plus non-major clinically relevant bleeding were recorded at day 10, day 35, and between days 11 and 35.

RESULTS

The frequency of VTE was 3.5-fold greater in patients with high D-dimer concentrations. Multivariate analysis showed that D-dimer was an independent predictor of the risk of VTE (odds ratio 2.29 [95% confidence interval 1.75-2.98]), and had a similar association to established risk factors for VTE, for example cancer and advanced age. In the high D-dimer group, rivaroxaban was non-inferior to enoxaparin at day 10 and, unlike the low D-dimer group, superior to placebo at day 35 (P < 0.001) and days 11-35 (P < 0.001). In both groups, bleeding outcomes favored enoxaparin/placebo.

CONCLUSIONS

Elevated baseline D-dimer concentrations may identify acutely ill, hospitalized medical patients at high risk of VTE for whom extended anticoagulant prophylaxis may provide greater benefit than for those with low D-dimer concentrations.

The contribution of immobility risk factors to the incidence of venous thrombosis in an older population

BACKGROUND

Venous thrombosis is common in the older population. Assessment of risk factors is necessary to implement preventive measures.

OBJECTIVES

We studied the associations between immobility-related risk factors and thrombosis, specifically, hospitalization, surgery, fractures, plaster cast use, minor injuries, and transient immobility at home, in an older population.

PATIENTS AND METHODS

Analyses were performed in the Age and Thrombosis, Acquired and Genetic risk factors in the Elderly (AT-AGE) study, a two-center population-based case-control study. Consecutive cases aged > 70 years with a first-time thrombosis (n = 401) and control subjects > 70 years old without a history of thrombosis (n = 431) were included. Exclusion criteria were active malignancy and severe cognitive disorders. We calculated odds ratios (OR) with 95% confidence intervals (95% CI) after adjustment for age, sex, body mass index, study center, and population-attributable risks.

RESULTS

There was a 15-fold (OR 14.8, 95% CI 4.4-50.4) increased risk of thrombosis within 2 weeks after hospital discharge. Surgery (OR 6.6, 95% CI 3.7-11.6), fractures (OR 12.7, 95% CI 3.7-43.7), plaster cast (OR 6.2, 95% CI 2.0-18.9), minor leg injuries (OR 1.9, 95% CI 1.1-3.3), and transient immobility at home (OR 5.0, 95% CI 2.3-11.2) were all associated with thrombosis risk over 3 months. The population-attributable risks for in-hospital immobility was 27%, and for out-of-hospital immobility, 15%.

CONCLUSIONS

In those > 70 years of age, in-hospital and out-of hospital immobility are strong risk factors for thrombosis. Additional studies on preventive measures during immobilization in this age group should not focus solely on hospital settings.

NOACs for thromboprophylaxis in medical patients

The risk of venous thrombosis extends for an indeterminate length of time following admission to hospital with a medical or surgical condition. Observational studies in surgery show this risk extends for months and perhaps more than one year, for medical patients the risk extends for at least several weeks. Large bodies of evidence support the heightened risk status of hospitalised surgical and medical patients, and that prophylactic measures significantly reduce the risk of thrombosis. Extending thromboprophylaxis for 4-6 weeks with anticoagulants both old and new has been shown to be efficacious and safe in surgical patients. However in populations of medical patients although prolonged anticoagulant thromboprophylaxis has been shown to be efficacious it also results in more bleeding and the risk benefit is not clear. Hence no therapies are approved for prolonged thromboprophylaxis in medical patients. In this area there have been one phase III study of low molecular weight heparin and two completed phase III studies of NOACs. This article briefly summarises our understanding of the background to preventing venous thromboembolism in hospitalised medical patients and reviews the details of the studies using NOACs.

Oral anticoagulants to reduce the risk of stroke in atrial fibrillation: how should a clinician choose?

Atrial fibrillation (AF), a common arrhythmia that occurs with increasing frequency in the aging population, is associated with increased mortality and morbidity. To ensure that patients receive adequate anticoagulant prophylaxis, clinical guidelines for anticoagulation advocate use of validated scoring systems to stratify patients by cardiovascular risk and predict the individual patient's risk of adverse effects of therapy. Recently approved oral anticoagulants-a direct thrombin inhibitor and the factor Xa inhibitors-may offer advantages over the 50-year standard, warfarin, for efficacy, safety, and ease of administration. Clinical trial experience with the newly approved agents and others, yet to be approved, will define their relative value in reducing the risk of thromboembolism associated with AF. This article discusses issues that may help clinicians choose among these newer agents and individualize treatment appropriately.

Rivaroxaban: an oral factor Xa inhibitor

BACKGROUND

Currently available anticoagulants utilized for venous thromboembolism (VTE) treatment and prevention and stroke prevention in patients with atrial fibrillation (AF) have proven effectiveness but are not optimally utilized because of barriers such as the need for subcutaneous administration and requisite routine laboratory monitoring. Rivaroxaban, a novel oral Xa inhibitor, is an alternative to standard therapies utilized for VTE prevention after elective orthopedic surgery, primary and secondary stroke prevention in nonvalvular AF, VTE treatment after an acute VTE event, and secondary prevention after the acute coronary syndromes (ACS).

OBJECTIVE

This article reviews the pharmacology, efficacy, and tolerability of rivaroxaban for VTE prophylaxis in post-orthopedic surgery and medically ill patients, stroke prevention in nonvalvular AF, adjunctive therapy in patients with ACS, and VTE treatment.

METHODS

International Pharmaceutical Abstracts and EMBASE were searched for English-only clinical trials and reviews published between 1970 and March 15, 2012. PubMed was searched for articles published between 1970 and June 30, 2012. Additional trials and reviews were identified from the citations of published articles.

RESULTS

Eighty-nine publications were identified: 10 clinical trials and 1 meta-analysis were used to obtain efficacy and tolerability data, and 1 analysis of pooled data from the clinical trials was included; 17 pharmacokinetic, pharmacodynamic, and drug-drug interaction studies were included; and 5 cost-analyses were reviewed. These data showed rivaroxaban to be noninferior to enoxaparin for thromboprophylaxis of VTE after total knee and total hip replacement surgery. It was also shown to be noninferior to vitamin K antagonist therapy for primary and recurrent stroke prevention in nonvalvular AF as well as for the treatment of VTE after an acute deep vein thrombosis or pulmonary embolism. It also showed benefit in lowering the risk for major adverse cardiovascular events after ACS. Differences in major bleeding rates were not statistically significant between rivaroxaban and comparators across the various studies, with the exception of ACS, in which there were higher rates of non-coronary artery bypass graft surgery related bleeding and intracranial hemorrhage.

CONCLUSIONS

Based on the findings of the studies reported in this review, rivaroxaban is an effective option for the prevention of VTE after orthopedic surgery, stroke prevention for nonvalvular AF, and treatment of VTE. At this time, rivaroxaban cannot be recommended for secondary risk reduction after ACS because of the increased bleeding risk.