Venous thromboembolism: A clinician update

Outpatient management of cancer-associated pulmonary embolism: A post-hoc analysis from the HOME-PE trial

INTRODUCTION

Cancer-related pulmonary embolism (PE) is associated with poor prognosis. Some decision rules identifying patients eligible for home treatment categorize cancer patients at high risk of complications, precluding home treatment. We sought to assess the effectiveness and the safety of outpatient management of patients with low-risk cancer-associated PE.

METHODS

In the HOME-PE trial, hemodynamically stable patients with symptomatic PE were randomized to either triaging with Hestia criteria or sPESI score. We analyzed 3 groups of low-risk PE patients: 47 with active cancer treated at home (group 1), 691 without active cancer treated at home (group 2), and 33 with active cancer as the only sPESI criterion qualifying them for hospitalization (group 3). The main outcome was the composite of recurrent venous thromboembolism, major bleeding, and all-cause death within 30 days after randomization.

RESULTS

Patients treated at home had composite outcome rates of 4.3 % (2/47) for those with cancer vs. 1.0 % (7/691) for those without (odds ratio (OR) 4.98, 95%CI 1.15-21.49). Patients with cancer had rates of complications of 4.3 % when treated at home vs. 3.0 % (1/33) when hospitalized (OR 1.19, 95%CI 0.15-9.47). In multivariable analysis, active cancer was associated with an increased risk of complications for patients treated at home (OR 7.95; 95%CI 1.48-42.82). For patients with active cancer, home treatment was not associated with the primary outcome (OR 1.19, 95%CI 0.15-9.74).

CONCLUSIONS

Among patients treated at home, active cancer was a risk factor for complications, but among patients with active cancer, home treatment was not associated with adverse outcomes.

Noninvasive and invasive imaging of lower-extremity acute and chronic venous thrombotic disease

The spectrum of venous thromboembolic (VTE) disease encompasses both acute deep venous thrombosis (DVT) and chronic postthrombotic changes (CPC). A large percentage of acute DVT patients experience recurrent VTE despite adequate anticoagulation, and may progress to CPC. Further, the role of iliocaval venous obstruction (ICVO) in lower-extremity VTE has been increasingly recognized in recent years. Imaging continues to play an important role in both acute and chronic venous disease. Venous duplex ultrasound remains the gold standard for diagnosing acute VTE. However, imaging of CPC is more complex and may involve computed tomography, magnetic resonance, contrast-enhanced ultrasound, or intravascular ultrasound. In this narrative review, we aim to discuss the full spectrum of venous disease imaging for both acute and chronic venous thrombotic disease.

Unprovoked Venous Thromboembolism: The Search for the Cause

Venous thromboembolism (VTE) is a common vascular disorder encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE). There is no data on global estimates of VTE prevalence and incidence. Most patients with unprovoked VTE require secondary thromboprophylaxis upon the completion of the primary treatment phase if they have no high bleeding risk. Risk prediction models can help identify patients at low VTE recurrence risk who may discontinue anticoagulation upon the completion of the primary treatment phase.

Epidemiology and Treatment Patterns of Venous Thromboembolism: an Observational Study of Nationwide Time-Series Trends in Japan

INTRODUCTION

Previous studies on anticoagulation treatment trends have mostly focused on hospitalized patients. This study aimed to clarify the treatment status of patients with venous thromboembolism (VTE) in Japan from 2011 to 2018, including outpatients, and to assess adherence with current guidelines.

METHODS

Data of inpatients and outpatients who were treated for VTE were extracted from a nationwide claims database (Medical Data Vision Co., Ltd., Tokyo, Japan) and analyzed.

RESULTS

The study included 79,330 patients with VTE; half were diagnosed during hospitalization for diseases other than VTE. The proportion of outpatient treatment increased significantly from 2015 to 2018 (Cochran-Armitage trend test, P < 0.0001), while 80% were anticoagulated in hospital after pulmonary embolism (PE) diagnosis. The proportion of patients with VTE treated as outpatients was no lower than the proportion of inpatients, even in the presence of active cancer, and there were no clear differences in anticoagulant choices. Treatment with direct oral anticoagulants (DOACs) did not always include the recommended initial intensification therapy. There was wide variation in the duration of DOAC treatment and the median duration of use was shorter than that recommended in VTE treatment guidelines.

CONCLUSION

While the gradual increase in VTE outpatient treatment appears to be in line with guideline recommendations, PE outpatient treatment could be further facilitated. The large proportion of patients diagnosed with VTE during hospitalization for other conditions suggests the importance of further utilizing in-hospital manuals for thrombosis prevention. The presence or absence of cancer did not appear to affect the basic treatment strategy of anticoagulation for VTE. Future studies are expected to better define the characteristics of patients who can be safely and effectively treated in an outpatient setting, and to examine whether anticoagulation for a shorter treatment period than recommended by the guidelines or DOAC therapy without initial intensification would improve patient outcomes.

Risk Assessment and Prophylaxis of Venous Thromboembolism in Patients of Medical Ward of Northwest General Hospital and Research Center, Peshawar, Pakistan: A Quality Improvement Project

Background Venous thromboembolism (VTE) is a condition that occurs when a blood clot forms in veins. Hospitalization increases the risk of VTE so timely risk assessment and adequate prophylaxis for VTE should be done to prevent this potentially fatal complication. Local problem Data from developing countries regarding VTE prophylaxis is scarce. VTE is a neglected area of research in Pakistan. So this closed-loop clinical audit was conducted to evaluate the VTE risk assessment and prophylaxis practices and to analyze the importance of educational intervention in improving the standard of care. Patients and methods We adopted the National Institute for Health and Care Excellence (NICE) guidelines for VTE prophylaxis as an audit standard. We collected data on a specially designed proforma by prospectively reviewing the hospital notes of patients in the Medical Ward of Northwest General Hospital and Research Center, Peshawar, Pakistan. Phase A included 60 patients and after educational intervention, Phase B was conducted with 90 patients. Intervention The results of Phase A were presented in the Clinicopathological Conference (CPC) meetings of the hospital. Healthcare workers were educated regarding the risks of VTE and the importance of timely prophylaxis. Posters were also displayed in the ward for highlighting the importance of VTE prophylaxis. Results In Phase A, only 5% of patients were risk assessed for VTE and of those eligible for prophylaxis only 22.2% received the prescription. Phase B showed a significant adherence to standard practices. In Phase B, 100% of patients were risk assessed for VTE and 75% received the prophylaxis. Conclusion There was poor compliance with standard VTE risk assessment and prophylaxis prescribing practices. However, a simple and effective educational intervention markedly improved patient care in terms of VTE strengthening the impact of clinical audits in the improvement of care.

The effects of information platform-based nursing on preventing venous thromboembolism in patients with hip fractures

PURPOSE

Venous thromboembolism (VTE) is a major health issue among hip fracture patients. This study aimed to develop an information platform based on a mobile application and then evaluate whether information platform-based nursing could improve patient's drug compliance and reduce the incidence of VTE in hip fracture patients.

METHODS

This study retrospectively analyzed hip fracture patients who were treated with conventional prevention and intervention methods for VTE (control group) between January 2008 and November 2012, and prospectively analyzed hip fracture patients who were treated with nursing intervention based on the information platform (study group) between January 2016 and September 2017. All the patients included in the both groups were hip fracture patients who had an age over 50 years, treated with surgery, and hospitalized ≥ 48 h. Patients were excluded if they admitted to hospital due to old fractures, had a severe bleeding after 72 h of admission, diagnosed with any type of VTE, or refused to participate in the study. The information platform was divided into medical, nursing, and patient interface. Based on the information platform, medical practitioners and nurses could perform risk assessments, monitoring management and early warnings, preventions and treatments, health educations, follow-up, and other aspects of nursing interventions for patients. This study compared essential characteristics, drug compliance, VTE occurrence, and mean length of hospitalization between the two groups. Besides, a subgroup analysis was performed in the study group according to different drug compliances. SPSS 18.0 software (IBM Corp., NY, and USA) was used for statistical analysis.

RESULTS

Altogether 1177 patients were included in the control group, and 491 patients in the study group. Regarding baseline data, patients in the study group had more morbidities than those in the control group (p < 0.05). The difference of drug compliance between the two groups was statistically significant (p < 0.001): 761 (64.7%) of the patients in the control group and only 30 (6.1%) patients in the study group had poor drug compliance. In terms of VTE, 10.7% patients (126/1177) in the control group had VTE, and the rate in the study group was 7.1% (35/491), showing a statistically significant difference (p = 0.02). Moreover, the average length of hospitalization in the study group was also significantly lower than that in the control group (10.4 days vs. 13.7 days, p < 0.001). Subgroup analyses of the study group showed that the incidence of VTE in patients with poor, partial, and good compliances were 56.7% (17/30), 5.8% (10/171), and 2.8% (8/290), respectively, revealing a significantly huge difference (p < 0.001).

CONCLUSIONS

Poor drug compliance leads to higher VTE occurrence. The information platform-based nursing can effectively improve the compliance of hip fracture patients and thus considerably reduce the incidence of VTE. The mobile application may be an effective tool to prevent VTE in hip fracture patients.

Assessment of Venous Thromboembolism Awareness Among Surgical Ward Patients in Makkah, Saudi Arabia: A Cross-Sectional Study

Introduction

Venous thromboembolism (VTE) is the leading source of morbidity and mortality among hospitalized patients in Saudi Arabia. Currently, there is no literature on VTE knowledge and awareness among hospitalized patients in Saudi Arabia’s western region. Consequently, this study aimed to investigate the hospitalized patients’ awareness and perceptions of VTE and associated thromboprophylaxis in surgical wards in Makkah, Saudi Arabia.

Methods

A descriptive cross-sectional study was conducted on 301 patients who were admitted to the surgical ward in the Al-Noor Hospital for more than three days, between September and November 2021.

Results

The study found that patients who had higher education levels, and who were currently or previously receiving pharmacological/non-pharmacological thromboprophylaxis had a significantly higher knowledge score regarding VTE (p = < 0.05). On the other hand, a non-significant relationship was found between knowledge scores and age, gender, the reason for admission, and personal or family history of VTE (p = > 0.05). Spearman’s correlation analysis also revealed a highly significant positive correlation between the patients’ knowledge and attitude scores (r=0.21, p=<0.001).

Conclusion

This study revealed a lack of awareness among hospitalized patients about VTE, clinical presentation, and risk factors. Therefore, we encourage health care providers to educate patients about them.

Exploring the Applicability of Using Natural Language Processing to Support Nationwide Venous Thromboembolism Surveillance: Model Evaluation Study

Background

Venous thromboembolism (VTE) is a preventable, common vascular disease that has been estimated to affect up to 900,000 people per year. It has been associated with risk factors such as recent surgery, cancer, and hospitalization. VTE surveillance for patient management and safety can be improved via natural language processing (NLP). NLP tools have the ability to access electronic medical records, identify patients that meet the VTE case definition, and subsequently enter the relevant information into a database for hospital review.

Objective

We aimed to evaluate the performance of a VTE identification model of IDEAL-X (Information and Data Extraction Using Adaptive Learning; Emory University)-an NLP tool-in automatically classifying cases of VTE by "reading" unstructured text from diagnostic imaging records collected from 2012 to 2014.

Methods

After accessing imaging records from pilot surveillance systems for VTE from Duke University and the University of Oklahoma Health Sciences Center (OUHSC), we used a VTE identification model of IDEAL-X to classify cases of VTE that had previously been manually classified. Experts reviewed the technicians' comments in each record to determine if a VTE event occurred. The performance measures calculated (with 95% CIs) were accuracy, sensitivity, specificity, and positive and negative predictive values. Chi-square tests of homogeneity were conducted to evaluate differences in performance measures by site, using a significance level of .05.

Results

The VTE model of IDEAL-X "read" 1591 records from Duke University and 1487 records from the OUHSC, for a total of 3078 records. The combined performance measures were 93.7% accuracy (95% CI 93.7%-93.8%), 96.3% sensitivity (95% CI 96.2%-96.4%), 92% specificity (95% CI 91.9%-92%), an 89.1% positive predictive value (95% CI 89%-89.2%), and a 97.3% negative predictive value (95% CI 97.3%-97.4%). The sensitivity was higher at Duke University (97.9%, 95% CI 97.8%-98%) than at the OUHSC (93.3%, 95% CI 93.1%-93.4%; P<.001), but the specificity was higher at the OUHSC (95.9%, 95% CI 95.8%-96%) than at Duke University (86.5%, 95% CI 86.4%-86.7%; P<.001).

Conclusions

The VTE model of IDEAL-X accurately classified cases of VTE from the pilot surveillance systems of two separate health systems in Durham, North Carolina, and Oklahoma City, Oklahoma. NLP is a promising tool for the design and implementation of an automated, cost-effective national surveillance system for VTE. Conducting public health surveillance at a national scale is important for measuring disease burden and the impact of prevention measures. We recommend additional studies to identify how integrating IDEAL-X in a medical record system could further automate the surveillance process.

Associations between coagulation factor XII, coagulation factor XI, and stability of venous thromboembolism: A case-control study

BACKGROUND

Pulmonary embolism (PE) is a fatal clinical syndrome that is generally caused by an embolus from unstable deep venous thrombosis (DVT). However, clinical and biochemical factors that are related to the stability of DVT are not fully understood.

AIM

To evaluate the relationships between plasma antigen levels of factor XII (FXII:Ag) and factor XI (FXI:Ag) with the stability of DVT.

METHODS

Patients with DVT and no PE, DVT and PE, and controls with no DVT or PE that matched for age, gender, and comorbidities were included in this study. FXII:Ag and FXI:Ag in peripheral venous blood were measured using enzyme-linked immunosorbent assays.

RESULTS

Using the 95^th percentile of FXI:Ag in patients with DVT and PE as the cut-off, a higher FXI:Ag was associated with a higher risk of unstable DVT (odds ratio: 3.15, 95% confidence interval: 1.18-8.43, P = 0.019). Stratified analyses showed consistent results in patients ≤ 60 years (P = 0.020), but not in those > 60 years (P = 0.346).

CONCLUSION

Higher plasma FXI:Ag might be a marker for unstable DVT, which might be associated with PE in these patients.

Associations between coagulation factor XII, coagulation factor XI, and stability of venous thromboembolism: A case-control study

BACKGROUND

Pulmonary embolism (PE) is a fatal clinical syndrome that is generally caused by an embolus from unstable deep venous thrombosis (DVT). However, clinical and biochemical factors that are related to the stability of DVT are not fully understood.

AIM

To evaluate the relationships between plasma antigen levels of factor XII (FXII:Ag) and factor XI (FXI:Ag) with the stability of DVT.

METHODS

Patients with DVT and no PE, DVT and PE, and controls with no DVT or PE that matched for age, gender, and comorbidities were included in this study. FXII:Ag and FXI:Ag in peripheral venous blood were measured using enzyme-linked immunosorbent assays.

RESULTS

Using the 95^th percentile of FXI:Ag in patients with DVT and PE as the cut-off, a higher FXI:Ag was associated with a higher risk of unstable DVT (odds ratio: 3.15, 95% confidence interval: 1.18-8.43, P = 0.019). Stratified analyses showed consistent results in patients ≤ 60 years (P = 0.020), but not in those > 60 years (P = 0.346).

CONCLUSION

Higher plasma FXI:Ag might be a marker for unstable DVT, which might be associated with PE in these patients.

Effects of Hyperthyroidism on Venous Thromboembolism: A Mendelian Randomization Study

Objective

Observational studies show the correlation between thyroid dysfunction and risk of venous thromboembolism. However, the causal effects remain uncertain. Our study was conducted to evaluate whether thyroid function and dysfunction were causally linked to the risk of venous thromboembolism.

Methods

Publicly available summary data of thyrotropin (TSH) and free thyroxine (FT4), hypothyroidism, and hyperthyroidism were obtained from the ThyroidOmics Consortium and the UK Biobank. With single nucleotide polymorphisms (SNPs) as instrumental variables, the casual effects of genetically predicted TSH and FT4 and hypo- and hyperthyroidism on venous thromboembolism outcome were estimated through Mendelian randomization analysis methods (inverse variance weighted (IVW), MR-Egger, weighted median, simple mode, and weighted mode). Cochran's Q test was performed to evaluate the heterogeneity and horizontal pleiotropy.

Results

Our study selected 15 FT4-, 36 TSH-, 3 hyperthyroidism-, and 79 hypothyroidism-associated SNPs as instrumental variables. The IVW analysis results showed that the odds ratio of venous thromboembolism for hyperthyroidism was 1.124 (95% confidence interval: 1.019-1.240; p = 0.019), demonstrating the casual effect of hyperthyroidism not FT4, TSH, and hypothyroidism on venous thromboembolism. No heterogeneity or horizontal pleiotropy was observed according to Cochran's Q test.

Conclusion

Our Mendelian randomization analysis supports the causal effect of hypothyroidism on risk of venous thromboembolism. There is no evidence that genetically predicted TSH, FT4, and hypothyroidism have casual effects on venous thromboembolism. Future studies should be conducted to elucidate the underlying pathophysiological mechanisms.

Factor Xa inhibitors: critical considerations for clinical development and testing

The selection of factor (F) X and its activated protease FXa for targeted inhibition to prevent and treat thrombotic conditions is based on an understanding of coagulation biochemistry, sequential steps that occur on tissue factor bearing cells and the interface of coagulation proteins, platelets, mononuclear cells and the nuclear constituents of inflammatory cells. The goal for developing direct oral FXa inhibitors was to achieve rapid, selective, predictable, safe and effective anticoagulation across a broad group of patients expected to derive benefit. The history and development in patient care are exemplars of knowledge, translation and collaboration between the public and private sectors.

Inappropriate Prescription of Direct Oral Anticoagulant Starter Packs

BACKGROUND

The 30-day direct oral anticoagulant starter pack has simplified the treatment of acute venous thromboembolisms, but it is not appropriate for use in patients with other indications for anticoagulation.

METHODS

A retrospective analysis of national outpatient pharmacy claims data between January 1, 2015 and December 31, 2018, was performed. Adult patients (ages >18 years) with continuous insurance enrollment at least 12 months prior to and 1 month following a direct oral anticoagulant starter pack prescription during the study period were included. The primary study outcome was the rate of inappropriate prescription of direct oral anticoagulant starter packs, defined as a prescription without a venous thromboembolism diagnosis within the prior 45 days or a prescription with a prior starter pack fill within the past 45 days.

RESULTS

A total of 3711 direct oral anticoagulant starter pack prescription fills were identified, representing 3634 unique patients. The mean patient age was 62.8 years (standard deviation [SD] 15.1) and 1871 (50.4%) were females. There were 770 (20.7%) direct oral anticoagulant starter pack fills identified as potentially inappropriate. Patients prescribed inappropriate fills were likely to be older than patients with appropriate fills (64.7 years vs 62.4 years, P < 0.001). There was no significant difference in the race or geographic location between patients with inappropriate and appropriate prescriptions.

CONCLUSIONS

A significant proportion of patients using direct oral anticoagulant starter packs did not have a diagnosis of acute venous thromboembolism, raising concerns about inappropriate prescribing and potential bleeding complications. Future studies are needed to identify factors associated with inappropriate direct oral anticoagulant starter pack prescription and evaluate efforts to reduce this practice.

Adverse outcomes associated with inappropriate direct oral anticoagulant starter pack prescription among patients with atrial fibrillation: a retrospective claims-based study

Direct oral anticoagulant (DOAC) starter packs are designed for unique treatment dosing for acute venous thromboembolism (VTE). Inappropriate use of 30-day DOAC starter packs in patients with atrial fibrillation (AF) may increase the risk for bleeding events given higher dosing in the first 1-3 weeks of treatment. A retrospective analysis of medical and outpatient pharmacy claims data from 2015 to 2018 in Optum's De-identified Clinformatics® Data Mart was performed. Patients greater than 18 years of age with AF and a new prescription of apixaban or rivaroxaban were included. Patients with an acute VTE were excluded. The main outcome of interest was adverse events (emergency department [ED] visits, hospitalizations, and deaths within 90 days after prescription fill date) associated with inappropriate DOAC starter pack prescription. A total of 90,950 DOAC-treated patients with AF were identified. The mean age was 74.5 years (SD 10.0) and 42,717 (47.0%) were female. Inappropriate starter packs were used by 117 (0.1%) patients, who were younger than non-starter pack patients (71.3 years vs. 74.5 years). Patients who received an inappropriate DOAC prescription were more likely to identify as Black (12.0% vs. 8.8%). Rates of ED visits, hospitalizations, and deaths overall were numerically lower in patients with starter pack compared to non-starter pack DOAC prescriptions. In contrast, rates of ED visits and hospitalizations related to significant bleeding were numerically higher in patients with starter pack compared to non-starter pack DOAC prescriptions. Among patients with AF but no VTE, those who received an inappropriate DOAC starter pack had numerically higher rates of severe bleeding leading to ED visits and hospitalizations compared to those prescribed an appropriate non-starter pack DOAC anticoagulant.

Knowledge and Awareness of Venous Thromboembolism in Intensive Care Units in Zhejiang Province, China: A Cross-Sectional Survey

Background

The 2009 China Intensive Care Units (ICU) prevention guidelines lack venous thromboembolism (VTE) risk assessment. This survey was conducted to assess the risk of VTE, develop and establish a diagnosis, and provide prevention and treatment guidelines for ICU VTE.

Material/Methods

A cross-sectional questionnaire survey of ICU doctors ICUs was conducted online in the tertiary and secondary hospitals of Zhejiang province in China. The questionnaire included VTE-related hospital hardware information, VTE awareness, knowledge, and monitoring system.

Results

The risk assessment rates at the time of admission and changed disease condition were 67.7% and 60.4%, respectively. D-dimer and ultrasound were commonly used for VTE screening. Heparin is preferred for short-term intravenous anticoagulant therapy, and warfarin is preferred for long-term therapy. We found that 23.53% of the ICUs have bedside ultrasound and staff for ultrasound examination, and 59.4% of the hospitals are equipped with VTE monitoring information systems. The VTE early identification specification is the key to whether the VTE assessment is performed after the patient enters the ICU.

Conclusions

The survey assessed the VTE risk and key VTE management elements. However, high heterogeneities were detected in the assessment. The ICU doctors have relatively limited awareness of VTE. Thus, there is an urgent need to update and standardize the ICU VTE guidelines for the prevention and treatment of VTE in China.

Safety of early orthopedic surgery in patients with intermediate/low- or low-risk pulmonary embolism

Background

Preoperative pulmonary embolism (PE) is one of the comorbidities in patients with hip fracture. However, previous studies have not identified the optimal timing of surgery in these patients, who might require early surgery. This study aimed to investigate the safety and clinical feasibility of early surgery in patients with hip fracture and acute PE.

Methods

The medical records of 156 patients with hip fracture, who were suspected to have PE and underwent pulmonary computed tomography angiography at Asan Medical Center from January 2008 to December 2017, were retrospectively reviewed. After excluding patients who were diagnosed with PE during the postoperative period, the baseline characteristics and clinical course were compared between patients preoperatively diagnosed with PE (PE group) and patients without PE during the hospital stay (non-PE group). Adverse outcomes were evaluated during 3 months postoperatively.

Results

The baseline characteristics were not different between the PE group (n=90) and the non-PE group (n=50). All patients in the PE group were classified as having an intermediate/low or low risk according to the European Society of Cardiology guidelines and underwent surgery within 30 days after the PE diagnosis (median duration: 2 days). None of the patients in both groups developed symptomatic venous thromboembolism (VTE) during the follow-up. Moreover, there were no statistically significant differences in major bleeding, clinically relevant nonmajor (CRNM) bleeding, transfusion amount, bleeding site, and length of hospital stay between the PE and non-PE groups.

Conclusions

Our results suggest that early surgery might be a reasonable treatment option in patients with hip fracture and acute PE.

Antithrombotic effects of heme-degrading and heme-binding proteins

In the murine venous thrombosis model induced by ligation of the inferior vena cava (IVCL), genetic deficiency of heme oxygenase-1 (HO-1) increases clot size. This study examined whether induction of HO-1 or administration of its products reduces thrombosis. Venous HO-1 upregulation by gene delivery reduced clot size, as did products of HO activity, biliverdin, and carbon monoxide. Induction of HO-1 by hemin reduced clot formation, clot size, and upregulation of plasminogen activator inhibitor-1 (PAI-1) that occurs in the IVCL model, while leaving urokinase plasminogen activator (uPA) and tissue plasminogen activator (tPA) expression unaltered. The reductive effect of hemin on clot size required HO activity. The IVCL model exhibited relatively high concentrations of heme that peaked just before maximum clot size, then declined as clot size decreased. Administration of hemin decreased heme concentration in the IVCL model. HO-2 mRNA was induced twofold in the IVCL model (vs. 40-fold HO-1 induction), but clot size was not increased in HO-2^-/- mice compared with HO-2^+/+ mice. Hemopexin, the major heme-binding protein, was induced in the IVCL model, and clot size was increased in hemopexin^-/- mice compared with hemopexin^+/+ mice. We conclude that in the IVCL model, the heme-degrading protein HO-1 and HO products inhibit thrombus formation, as does the heme-binding protein, hemopexin. The reductive effects of hemin administration require HO activity and are mediated, in part, by reducing PAI-1 upregulation in the IVCL model. We speculate that HO-1, HO, and hemopexin reduce clot size by restraining the increase in clot concentration of heme (now recognized as a procoagulant) that otherwise occurs.NEW & NOTEWORTHY This study provides conclusive evidence that two proteins, one heme-degrading and the other heme-binding, inhibit clot formation. This may serve as a new therapeutic strategy in preventing and treating venous thromboembolic disease.

Lung Adenocarcinoma Presenting as Multiple Thromboembolic Events: A Case Report and Review of the Literature

Patients with malignancy may present with significant thromboembolic complications including deep vein thrombosis (DVT), pulmonary embolism, arterial thrombosis, nonbacterial thrombotic endocarditis, and stroke due to abnormal coagulation cascades. Although these events are typically recognized later in the disease process, complications of a hypercoagulable state can rarely present as the first manifestation of an occult malignancy. We report a case of a young male who was ultimately found to have an aggressive form of lung adenocarcinoma after the initial presentation of multiple thromboembolic events. DVT and stroke as an initial presentation of an active lung adenocarcinoma in a young patient is extremely rare as patients presenting in a hypercoagulable state usually are older. Though testing for a hypercoagulable state is not recommended for the first unprovoked DVT, clinicians should be prompted to screen for malignancy in the setting of cryptogenic strokes, especially in younger patients with no prior risk factors.

Direct-Acting Oral Anticoagulants and Their Reversal Agents-An Update

Background: Over the last ten years, a new class of drugs, known as the direct-acting oral anticoagulants (DOACs), have emerged at the forefront of anticoagulation therapy. Like the older generation anticoagulants, DOACs require specific reversal agents in cases of life-threatening bleeding or the need for high-risk surgery. Methods: Published literature was searched, and information extracted to provide an update on DOACS and their reversal agents. Results: The DOACs include the direct thrombin inhibitor—dabigatran, and the factor Xa inhibitors—rivaroxaban, apixaban, edoxaban, and betrixaban. These DOACs all have a rapid onset of action and each has a predictable therapeutic response requiring no monitoring, unlike the older anticoagulants, such as warfarin. Two reversal agents have been approved within the last five years: idarucizumab for the reversal of dabigatran, and andexanet alfa for the reversal of rivaroxaban and apixaban. Additionally, ciraparantag, a potential “universal” reversal agent, is currently under clinical development. Conclusions: A new generation of anticoagulants, the DOACs, and their reversal agents, are gaining prominence in clinical practice, having demonstrated superior efficacy and safety profiles. They are poised to replace traditional anticoagulants including warfarin.

Assessment of the adherence to and costs of the prophylaxis protocol for venous thromboembolism

OBJECTIVES

Evaluate adherence to the therapeutic prophylaxis protocol for venous thromboembolism (VTE) as well as the costs of this practice.

METHODS

A descriptive and cross-sectional study was conducted at a State General Hospital in Brazil through reports of drug dispensions, prescriptions and risk stratification of patients. Adherence to the VTE prophylaxis protocol was monitored. The tests for VTE diagnosis measured the adherence to therapeutic prophylaxis treatment, and the purchase prices of the drugs went into the calculation of drug therapy costs. The level of adherence to prescriptions for VTE prophylaxis in the hospital was classified as "adherence", "non-adherence" and "justified non-adherence" when compared with the protocol.

RESULTS

Protocol adherence was observed for 50 (30.9%) patients, and non-adherence was observed for 63 (38.9%) patients, generating an additional cost of $180.40/month. Justified non-adherence in 49 (30.2%) patients generated $514.71/month in savings due to a reduction in the number of daily administrations of unfractionated heparin while still providing an effective method for preventing VTE. Twenty-six patients stratified as having medium to high risk of VTE who did not receive prophylaxis were identified, generating $154.41 in savings. However, these data should be evaluated with caution since the risks and outcomes associated with not preventing VTE outweigh the economy achieved from not prescribing a drug when a patient needs it. The only case of VTE identified during the study period was related to justified non-adherence to the protocol.

CONCLUSION

The protocol is based on scientific evidence that describes an effective therapy to prevent VTE. However, the protocol should be updated because the justifications for non-adherence are based on scientific evidence, and this justified non-adherence generates savings and yields effective disease prevention.