Acute phase treatment of VTE: Anticoagulation, including non-vitamin K antagonist oral anticoagulants

Altitude-Related Venous Thrombosis With Heart Disease: An Updated Review

Altitude-related venous thrombosis (ARVT) is a condition of growing concern among individuals engaged in high-altitude travel and activities. This updated review explores the epidemiology, pathophysiological mechanisms, clinical presentations, and management of ARVT based on a thematic analysis and synthesis of the existing literature. ARVT's multifactorial etiology involves the interplay of hypobaric hypoxia and endothelial dysfunction, creating a procoagulant state and increasing the risk of thrombosis. Common clinical manifestations include pain, swelling, and redness in the extremities, necessitating accurate and timely diagnosis, particularly in remote settings. Thromboprophylaxis during high-altitude travel and activities plays a crucial role in reducing the risk of ARVT, while anticoagulation remains the mainstay of management. Further research is needed to optimize preventive and treatment strategies, enhancing patient outcomes and safety in high-altitude environments.

Evaluation of anti-Xa levels in patients with venous thromboembolism within the first 48 h of anticoagulation with unfractionated heparin

Background: A 2019 study by Prucnal and colleagues found that the majority of patients treated with unfractionated heparin for pulmonary embolism did not maintain therapeutic activated partial thromboplastin time levels during the first 48 h of therapy. Objective: The purpose of this study was to evaluate the ability of an institution's unfractionated heparin dosing protocol to achieve and maintain therapeutic anti-Xa levels within the first 48 h of therapy in patients with venous thromboembolism. Methods: This retrospective study included 205 patients from May 2016 through September 2020. Patients were divided into two cohorts: bolus plus infusion (N = 89) and infusion only (N = 116). The primary objective was to determine the number of patients who achieved at least one therapeutic level. Results: Overall, 200 patients (97.6%) had at least one therapeutic level with no statistically significant difference between cohorts (p = 0.65). No more than 60% of patients achieved a therapeutic level at any of the 6-h intervals throughout the timeframe. The median time to the first therapeutic level in the overall group was 12.8 h with no statistically significant difference between the bolus plus infusion and infusion-only cohorts (13.3 h versus 12.7 h, respectively, p = 0.48). Conclusions: Most patients were able to achieve at least one therapeutic level within the first 48 h, but fewer were able to maintain therapeutic levels. Further studies are warranted to determine whether alternative dosing strategies would yield consistent achievement of therapeutic levels and affect patient-oriented outcomes.

Comparative Effectiveness of Apixaban and Rivaroxaban Lead-in Dosing in VTE Treatment: Observational Multicenter Real-World Study

Apixaban and rivaroxaban require lead-in dosing for 7 and 21 days, respectively, when treating venous thromboembolism (VTE). However, no evidence exists to support subtracting parenteral anticoagulation days from total lead-in dosing. A multicenter study was conducted, including adult patients with acute VTE who received apixaban or rivaroxaban. The patients were grouped as follows. The recommended group received oral lead-in anticoagulant for the full recommended duration. The mixed group received lead-in therapy as parenteral with oral anticoagulant. The incidence of recurrent VTE (rVTE) and major bleeding (MB) within 90 days were the main outcomes. Of the 368 included patients, 47.8% received apixaban, and 52.2% received rivaroxaban. The recommended lead-in was used in 296 patients (80.4%), whereas 72 (19.6%) received the mixed-lead-in regimen. Five patients had rVTE events within 90 days; two occurred during hospitalization in the recommended group versus none in the mixed group (0.7% vs. 0.0%; p = 1.000). After discharge, two events occurred in the recommended group and one in the mixed group (0.7% vs. 1.4%; p = 0.481). In terms of MB, 24 events occurred in 21 patients within 90 days. During hospitalization, 11 events occurred in the recommended group and seven in the mixed group (3.7% vs. 9.7%; p = 0.060). After discharge, five more events occurred in the recommended group and one in the mixed group (1.4% vs. 1.7%; p = 1.000). The mixed-lead-in regimen is safe and effective in comparison with the recommended-lead-in regimen.

Comparison Between the Diagnostic Performance of 1.5 T and 3.0 T field Strengths for Detecting Deep Vein Thrombosis Using Magnetic Resonance Black-Blood Thrombus Imaging

BACKGROUND

Magnetic resonance (MR) black-blood thrombus imaging (BTI) is an accurate diagnostic technique for detecting deep vein thrombosis (DVT) but to date there have been no studies comparing the diagnostic performance and consistency of this technique at different field strengths. In this study, we evaluated and compared the diagnostic performance of BTI for detecting DVT at 1.5 T and 3.0 T field strengths.

METHODS

A total of 40 patients with DVT were enrolled in this study from November 2015 up to October 2018. All patients underwent BTI, a contrast-free T1-weighted MR imaging technique for detecting DVT, and contrast-enhanced MR venography (CE-MRV) at 1.5 T or 3.0 T field strengths. The MR data analyses used 1160 segments from the venous lumen of the 40 patients. The signal-to-noise ratio and contrast-to-noise ratio between thrombus and muscle/lumen were calculated to compare BTI at 1.5 T or 3.0 T to determine the image performance for thrombus detection at 1.5 T or 3.0 T. Two physicians blinded to the study evaluated all BTI images and calculated the overall sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV), accuracy, and diagnostic consistency at 1.5 T and 3.0 T. These images and values were compared to control CE-MRV images that had been obtained by 2 senior physicians and used as reference standards. In addition, the reliability and consistency of diagnoses between observers were also evaluated.

RESULTS

Two study-blind physicians reviewed all BTI images to diagnose thrombus and to determine SE, SP, PPV, NPV, and accuracy. There were no statistical differences in SE, SP, PPV, NPV, or accuracy between the 1.5 T and 3.0 T groups.

CONCLUSIONS

Black-blood thrombus imaging has high SE, SP, and accuracy for DVT diagnosis both at 1.5 T and 3.0 T field strengths. This noninvasive diagnostic technique, which does not require the use of contrast agents, can be widely used in the clinical screening of DVT and follow-up after treatment.

Pulmonary embolism treatment. Detection of chronic thromboembolic pulmonary hypertension

The correct stratification of pulmonary embolism risk (PE) is essential for decision-making, regarding treatment and defining the patient's place of admission. In high-risk PE, urgent re-establishment of pulmonary circulation and admission to a critical unit is required. The reperfusion treatment of choice is systemic thrombolysis, although in certain situations, especially when there is a contraindication for it, we will evaluate a surgical embolectomy or one of the catheter-guided therapies. In the rest of PE, the treatment of choice will be anticoagulation. Currently, direct oral anticoagulants have become the treatment of choice for the treatment of PE, due to their better safety profile. However, low molecular weight heparins and subsequently antivitamins K, remain the most used treatment, because they are funded by the public system. In cases of PE with cardiorespiratory arrest and / or cardiogenic shock, whenever available at our center, we must consider the indication of extracorporeal membrane oxygenation. The recent creation of PE response teams (PERT team), have meant an improvement in the care of patients with intermediate-high and high risk PE. During the follow-up of patients with PE, it is essential to perform a correct screening of chronic thromboembolic pulmonary hypertension, in order to perform a correct diagnostic and therapeutic approach.

Analysis of Partial Thromboplastin Times in Patients With Pulmonary Embolism During the First 48 Hours of Anticoagulation With Unfractionated Heparin

OBJECTIVE

The objective was to determine the proportion of patients with pulmonary embolism (PE) treated with unfractionated heparin (UFH) who achieved therapeutic activated partial thromboplastin time (aPTT) values within 48 hours of treatment.

METHODS

Retrospective analysis of a PE response team (PERT) database was performed at a large, urban, academic teaching hospital. Inclusion criteria were adult patients with acute PE for whom the PERT was consulted and who received anticoagulation (AC) with UFH according to guideline standard dosing. aPTT values during 6-hour time periods during the first 48 hours of AC were collected and analyzed.

RESULTS

A total of 505 patients met inclusion criteria. For patients receiving a bolus and infusion of UFH, the proportions (95% confidence interval [CI]) of patients in the therapeutic range were 19.0% (14.2% to 25.0%) at 12 hours, 26.3% (26.3% to 33.1%) at 24 hours, 28.3% (22.0% to 35.4%) at 36 hours, and 28.4% (20.8% to 37.5%) at 48 hours. For titrated infusion only, the proportions (95% CIs) of patients were 23.3% (16.2% to 32.3%) at 12 hours, 41.4% (31.6% to 51.9%) at 24 hours, 37.0% (26.8% to 48.5%) at 36 hours, and 42.1% (30.2% to 55.0%) at 48 hours. No patient had all therapeutic aPTT values.

CONCLUSIONS

The majority of patients with acute PE spend most of their first 48 hours outside of the therapeutic range of AC when treated with guideline standard dosing of UFH. Over half of the patients fail to achieve any therapeutic PTT level within 24 hours of UFH initiation, and no patient had all therapeutic aPTTs. Future research should focus on identifying factors associated with achieving therapeutic AC with UFH.

Prospective Registry of Rivaroxaban Management of Cancer-Associated Venous Throboembolism (PRIMECAST) Study

Background: The incidence of thromboembolism in patients with cancer is approximately 11%, and the risk of thrombosis in patients with malignant tumors is 6-fold higher than that in healthy persons. Thrombosis not only disrupts the treatment of cancer but also induces deterioration of quality of life (QOL). Knowledge about thrombus treatment is limited, and evidence is scarce. Clarification of the status and safety of venous thromboembolism (VTE) treatment in patients with cancer will contribute to active intervention and improvement of prognosis and QOL. In this study, the therapeutic effects of a non-vitamin K antagonist oral anticoagulant for VTE and the prognosis of cancer after treatment will be examined to establish a therapeutic method for VTE in patients with cancer.

Methods and Results: A multicenter, non-interventional, observational study will be conducted in patients with cancer who developed VTE and underwent anticoagulant therapy with rivaroxaban (group A) or warfarin (group B) for 24 weeks. The primary endpoint will be the recurrence/aggravation of symptomatic VTE or occurrence/aggravation of deep vein thrombosis. Registration of 500 patients is needed in order to calculate the 95% confidence interval of the event rate at ±1% precision.

Conclusions: The investigation period will run from January 2019 to December 2023 with ongoing selection of patients. Trial registration: no. 5-18-32 (approved 1 August 2018).

Insights from thrombi retrieved in stroke due to large vessel occlusion

The recent advances of endovascular procedures to treat stroke due to large cerebral vessel occlusion have made it possible to analyze the retrieved thrombus material. Analysis of cerebral thrombi is emerging as a relevant opportunity to complement the diagnostic workup of etiology, to develop new lytic approaches and to optimize the acute treatment of stroke due to large vessel occlusion. Nonetheless, retrieved thrombi are frequently discarded since their informative potential is often neglected and standards are missing. This review provides an overview of the current knowledge and expanding research relating to thrombus composition analysis in large vessel occlusions. We first discuss the heterogeneity of thrombogenic factors that underlie the thrombotic formation in stroke and its implications to identify stroke etiology and thrombus age. Further, we show that understanding structural characteristics of thrombus is pivotal for the development of new-targeted lytic therapies as well as to improve, through thrombus modeling, the development of thrombectomy devices. Finally, we discuss the on-going attempts to identify a signature of thrombus composition indirectly through imaging and peripheral blood biomarkers, which might in future assist treatment decision-making as well as secondary prevention. Thrombus analysis might contribute to the advancement and optimization of personalized stroke treatments.

Can thrombus age guide thrombolytic therapy?

Venous thrombosis (VT) is a common yet complex clinical condition that has shown minimal alteration in clinical management for decades. It is well known that thrombus evolves structurally over time, with complex changes resulting from the interplay between coagulation factors, cytokines, leukocytes and a myriad of other factors. Our current treatment options are most effective in the acute thrombus, which is composed predominantly of a loose mesh of fibrin and red blood cells (RBCs), making current anticoagulation therapies and thrombolytics quite effective in treatment. Later stages of thrombus are more cellular containing leukocytes, and develop a fibrotic collagenous framework that is more resistant to our current treatments. Understanding the biology of an evolving thrombus will allow us to tailor our treatment and optimize outcomes, as well as focus on novel therapies for the treatment of chronic thrombus. Given the morbidity and mortality of both post thrombotic syndrome (PTS) in patients with deep VT, as well as chronic thromboembolic pulmonary hypertension (CTEPH) in patients with pulmonary embolism (PE), new and innovative therapies must continue to be explored to help prevent these potentially devastating conditions.

Animal models of venous thrombosis

Venous thrombosis (VT) is a prevalent clinical condition with significant adverse sequela or mortality. Anticoagulation and pharmacologic or pharmacomechanical thrombolytic therapies are the mainstays of VT treatment. An understanding of thrombosis biology will allow for more effective VT-tailored diagnosis and therapy. In vivo models of thrombosis provide indispensable tools to study the pathogenesis of thrombus formation and to evaluate novel therapeutic or preventive adjuncts for VT management or prevention. In this article, we review the most prominent in vivo models of VT created in rodents and swine species and outline how each model can serve as a useful tool to promote our understanding of VT pathogenesis and to examine novel therapies.

Dabigatran versus Warfarin for Acute Venous Thromboembolism in Elderly or Impaired Renal Function Patients: Pooled Analysis of RE-COVER and RE-COVER II

Management of acute venous thromboembolism (VTE) with anticoagulants in elderly patients and those with chronic kidney disease poses special challenges. The RE-COVER and RE-COVER II trials showed that dabigatran 150 mg twice daily was as effective as warfarin over 6 months in preventing recurrent VTE, with a lower bleeding risk. We now assess the effects of old age and renal impairment (RI) on pooled trial outcomes in 5,107 patients: 4,504 aged <75 years and 603 aged ≥75 years. The primary efficacy outcome was symptomatic VTE/VTE-related death. Safety outcomes were centrally adjudicated major bleeding events (MBEs), MBEs or clinically relevant non-major bleeding events (MBEs/CRBEs) and any bleeds. Baseline renal function was categorized as normal, mild RI or moderate RI. A total of 3,698 had normal renal function and 1,100 and 237 had mild and moderate RI, respectively (23 patients with severe RI and 49 with missing creatinine clearance data were not included). For dabigatran, VTE/VTE-related death decreased from 3.1% (normal renal function) to 1.9% for mild RI and to 0.0% for moderate RI. For warfarin, the event rates were 2.6, 1.6 and 4.1%, respectively. Overall, major bleeding increased with increasing RI (p = 0.0037) and with age (p = 0.4350), with no apparent difference between the dabigatran and warfarin patients. Dabigatran shows better efficacy than warfarin in RI and in the elderly patients, probably because of an increase in the concentration of dabigatran. However, bleeding risk increases with both dabigatran and warfarin in the presence of RI.

Direct oral anticoagulant reversal: how, when and issues faced

INTRODUCTION

The number of atrial fibrillation (AF) patients requiring thrombo-prophylaxis with oral anticoagulation is greatly increasing. The introduction of non-vitamin K oral anticoagulants (NOACs) in addition to standard therapy with dose-adjusted warfarin has increased the therapeutic options for AF patients. Despite a generally better safety profile of the NOACs, the risk of major bleedings still persists, and the management of serious bleeding is a clinical challenge. Areas covered: In the current review, risk of major bleeding in patients taking NOACs and general approaches to manage bleeding depending on severity, with a particular focus on specific reversal agents, are discussed. Expert commentary: Due to short half-life of NOACs compared to warfarin, discontinuation of drug, mechanical compression, and volume substitution are considered to be sufficient measures in most of bleeding cases. In case of life-threatening bleeding or urgent surgery, hemostasis can be achieved with non-specific reversal agents (prothrombin complex concentrates) in patients treated with factor Xa inhibitor until specific antidotes (andexanet α and ciraparantag) will receive approval. Thus far, idarucizumab has been the only reversal agent approved for dabigatran.

Hypercoagulation and complement: Connected players in tumor development and metastases

Hypercoagulation is a common feature of several tumors to the extent that individuals with coagulation defects often present with occult visceral cancers. Recent evidence has shown that hypercoagulation is not just a mere secondary effect due to the presence of the tumor, rather it actively contributes to tumor development and dissemination. Among the numerous mechanisms that can contribute to cancer-associated hypercoagulation, the ones involving immune-mediated processes are gaining increasing attention. In particular, complement cascade and hypercoagulation are one inducing the other in a vicious circle that involves neutrophil extracellular traps (NETs) formation. Together, in this feedback loop, they can promote the protumorigenic phenotype of immune cells and the protection of tumor cells from immune attack, ultimately favouring tumor development, progression and metastases formation. In this review, we summarize the role of these processes in cancer development and highlight new possible intervention strategies based on anticoagulants that can arrest this vicious circle.

Successful use of rivaroxaban in postoperative deep vein thrombosis of the lower limb following instability with warfarin: a case report

Background

Evidence from clinical trials shows rivaroxaban to be effective for the treatment of deep vein thrombosis. Switching to rivaroxaban following failure of indirect anticoagulants in deep vein thrombosis has not been demonstrated in a real-life setting.

Case presentation

A 43-year-old white woman was switched from warfarin to rivaroxaban for the treatment of thrombosis of her right common femoral vein after saphenectomy. The reason for the switch was due to the instability of anti-coagulation therapy with vitamin K antagonists over a period of 3 months during which she did not reach the “therapeutic range” of prothrombin time-international normalized ratio.

The ineffectiveness of the conventional oral anticoagulant was confirmed by persistence of moderate-high values of fibrin D dimers (780 ng/ml) and by residual vein thrombosis at an ultrasound examination. Objectively, her right leg appeared to be still edematous and warm and pain was elicited by deep palpation. Rivaroxaban was administered after warfarin discontinuation (prothrombin time-international normalized ratio = 1.43) at a dosage of 15 mg every 12 hours for 3 weeks, followed by 20 mg once daily for 3 months. After this period, her objective symptoms significantly improved, with reduction of edema of her lower limb and pain relief. Her fibrin D dimer values returned to normal (210 ng/ml). An ultrasound showed recanalization of the obstructed venous segment.

Conclusions

In this case report, a switch to rivaroxaban from warfarin was shown to be effective and safe for the treatment of postoperative deep vein thrombosis, whereas standard oral anticoagulation therapy, which required dose adjustments over a period of 3 months, was not able to stabilize the therapeutic range of prothrombin time-international normalized ratio nor improve our patient’s outcome.

Obesity and lower limb venous disease - The epidemic of phlebesity

Introduction Lower limb venous disease affects up to one half, and obesity up to one quarter, of the adult population. Many people are therefore affected by, and present to health services for the treatment of both conditions. This article reviews the available evidence of pathophysiological and clinical relationship between obesity and varicose veins, chronic venous insufficiency and ulceration and deep vein thrombosis. Methods A literature search of PubMed and Cochrane libraries was performed in accordance with PRISMA statement from 1946 to 2015, with further article identification from following cited references for articles examining the relationship between obesity and venous disease. Search terms included obesity, overweight, thrombosis, varicose veins, CEAP, chronic venous insufficiency, treatment, endovenous, endothermal, sclerotherapy, bariatric surgery and deep vein thrombosis. Results The proportion of the population suffering from lower limb venous disease and obesity is increasing. Obesity is an important risk factor for all types of lower limb venous disease, and obese patients with lower limb venous disease are more likely to be symptomatic as a result of their lower limb venous disease. The clinical diagnosis, investigation, imaging and treatment of lower limb venous disease in obese people present a number of challenges. The evidence base underpinning medical, surgical and endovenous management of lower limb venous disease in obese people is limited and such treatment may be associated with worse outcomes and increased risks when compared to patients with a normal body mass index. Conclusion Lower limb venous disease and obesity are both increasingly common. As such, phlebologists will be treating ever greater numbers of obese patients with lower limb venous disease, and clinicians in many other specialties are going to be treating a wide range of obesity-related health problems in people with or at risk of lower limb venous disease. Unfortunately, obese people have been specifically excluded from many, if not most, of the pivotal studies. As such, many basic questions remain unanswered and there is an urgent need for research in this challenging and increasingly prevalent patient group.

Aspirin and heparin in pregnancy

INTRODUCTION

A pro-coagulant state during pregnancy can be involved in the occurrence of gestational vascular complications (GVCs) and venous thromboembolism (VTE).

AREAS COVERED

Antithrombotic drugs are used to prevent GVCs and VTE. Aspirin is not efficacious to prevent recurrences in women with previous early loss, while it can prevent pre-eclampsia in some groups of women. Heparins are not effective in the prevention of early recurrent loss and there is uncertainty about their efficacy in women carrying inherited thrombophilias. They could be efficacious in the prevention of GVCs in carriers of inherited thrombophilias, as GVCs have heterogeneous causes, and future studies have to focus on more homogeneous groups of patients. Not enough data are available regarding prophylaxis with heparins to prevent pregnancy-related VTE, but an accurate risk stratification of women during pregnancy and puerperium is crucial for administering prophylaxis in moderate-/high-risk women. Aspirin does not improve live births after assisted reproductive technologies, while heparins increase the number of clinical pregnancies and live births.

EXPERT OPINION

Aspirin is efficacious in the prevention of GVCs in women at risk for pre-eclampsia and in those with antiphospholipid antibodies syndrome. Heparins could give benefit to women at risk for GVCs and/or pregnancy-related VTE.