New paradigms in venous thromboprophylaxis of medically ill patients

System-Wide Thromboprophylaxis Interventions for Hospitalized Patients at Risk of Venous Thromboembolism: Focus on Cross-Platform Clinical Decision Support

Thromboprophylaxis of hospitalized patients at risk of venous thromboembolism (VTE) presents challenges owing to patient heterogeneity and lack of adoption of evidence-based methods. Intuitive practices for thromboprophylaxis have resulted in many patients being inappropriately prophylaxed. We conducted a narrative review summarizing system-wide thromboprophylaxis interventions in hospitalized patients. Multiple interventions for thromboprophylaxis have been tested, including multifaceted approaches such as national VTE prevention programs with audits, pre-printed order entry, passive alerts (either human or electronic), and more recently, the use of active clinical decision support (CDS) tools incorporated into electronic health records (EHRs). Multifaceted health-system and order entry interventions have shown mixed results in their ability to increase appropriate thromboprophylaxis and reduce VTE unless mandated through a national VTE prevention program, though the latter approach is potentially costly and effort- and time-dependent. Studies utilizing passive human or electronic alerts have also shown mixed results in increasing appropriate thromboprophylaxis and reducing VTE. Recently, a universal cloud-based and EHR-agnostic CDS VTE tool incorporating a validated VTE risk score revealed high adoption and effectiveness in increasing appropriate thromboprophylaxis and reducing major thromboembolism. Active CDS tools hold promise in improving appropriate thromboprophylaxis, especially with further refinement and widespread implementation within various EHRs and clinical workflows.

Venous Thromboembolism Prophylaxis in Medical and Surgical Patients - What's Our Reality?

INTRODUCTION

Venous thromboembolism (VTE) includes pulmonary embolism (PE), deep vein thrombosis (DVT) in lower limbs, and thrombosis in rare locations. VTE is a common cardiovascular disease, being the leading preventable cause of in-hospital death. Both surgical and acute medical patients have an elevated risk of developing VTE. VTE risk assessment is essential to identify patients who might benefit from VTE prophylaxis accurately. Clinical data on risk factors and prophylaxis in Portugal are scarce. We aimed to determine the proportion of at-risk patients who received prophylaxis and the incidence of bleeding events. We also intended to study the rate of VTE in a cohort of medical and surgical patients during the hospitalization period and three months after discharge.

METHODS

During one week in 2020, adults admitted for more than 72hr to a medical or surgical ward were included. The study excluded patients with a diagnosis of VTE three months before hospitalization and who were either chronically receiving anticoagulation therapy or had started it 48 hours after admission. Risk assessments were based on the Padua Prediction Score (PPS) for medical patients and the Caprini Risk Assessment Model (CRAM) for surgical patients. We used CHEST guidelines, 9th edition, to determine the adequacy of the prophylactic method.

RESULTS

A total of 123 patients were analyzed, 18.7% of which tested positive for SARS-CoV-2. VTE risk in surgical patients was categorized as very low or low (16.6%), moderate (37.5%), and high (43.8%), according to the CRAM. Risk in medical patients was categorized as low (60.0%) or high (40.0%) according to the PPS. We estimated that VTE chemoprophylaxis was overused in about 30.0% of patients vs. 7.0% who were at risk and did not receive appropriate chemoprophylaxis. The rate of thromboembolic events was 4.1% (n=5), 2 of which happened after discharge. Two of these patients were under VTE prophylaxis during hospitalization. Major bleeding occurred in 2.4% of patients (n=3).

DISCUSSION

A significant number of hospitalized patients are deemed to be at risk for VTE, making appropriate prophylaxis essential. The results emphasize the insufficient management of VTE prophylaxis.

Views of inpatients on the prevention of venous thrombosis with ankle pump exercise: A cross-sectional survey

INTRODUCTION

This study investigated the current status of patients' knowledge and clinical compliance with ankle pump exercises in order to better enhance patient education and improve patient compliance with ankle pump exercises.

METHODS

A cross-sectional survey of the current status of ankle pump exercise awareness and compliance was conducted using a self-designed questionnaire. The questionnaire consisted of a general demographic information questionnaire, a questionnaire on patients' perceptions of ankle pump exercise and a compliance questionnaire.

RESULTS

A total of 2,203 patients from 53 clinical departments participated in this survey. 87.8% of patients considered ankle pump exercise important, 92.1% could grasp the knowledge of ankle pump exercise, 48.5% could self-monitor and exercise daily as instructed, 81.5% of health care workers would often supervise patients to complete ankle pump exercise, poor self-control (34.6%), lack of physical strength (21.1%) and perceived hassle (18.9%) were the top 3 factors contributing to patients' inability to complete the ankle pump exercise. Regression analysis showed that the factors influencing patients' compliance with the ankle pump exercise were literacy, economic level, number of comorbidities and caprini risk class (p < .05).

CONCLUSION

The patient's cognition of ankle pump exercise is good, but the compliance needs to be improved. It is suggested that the compliance of ankle pump exercise in hospitalized patients should be improved in the future to reduce the incidence of Venous thromboembolism.

A review of venous thromboembolism risk assessment models for different patient populations: What we know and don't!

Venous thromboembolism (VTE) is a common cause of morbidity and mortality in hospitalized patients. Globally, it is also the third leading vascular disease, after myocardial infarction and stroke. The incidence of VTE is reportedly higher in Western countries than in Asian countries. However, recent reports suggest an increasing incidence of VTE in Asian countries, including India. Since VTE is largely a preventable disease, early identification of risk factors can lead to disease prevention or the adoption of appropriate prophylactic measures. To this end, several VTE risk assessment models (RAMs) have been developed and validated for different populations who are at risk of developing VTE, such as hospitalized patients with medical illness/surgical indication, patients with cancer, and pregnant women. Evidence indicates that the systematic use of RAMs improves prophylaxis rates and lowers the burden of VTE. Given the increasing burden of VTE in the Indian population and poor prophylaxis rates, the implementation of systematic RAMs in routine clinical practice might ameliorate the disease burden in the country. We have assessed the evidence-based utilities of available RAMs and have delineated the most common and suitable RAMs for different populations including coronavirus disease 2019 affected patients. This review depicts the current status of implementation and validation of RAMs in the Indian scenario. It also highlights the need for additional validation studies, improved awareness, and implementation of RAMs in clinical practice for lowering the burden of VTE.

Estimating Venous Thromboembolism Risk in Metastatic Colorectal Cancer Inpatients: Validation of Existing Risk Scores and Development of New Risk Scores

Metastatic colorectal cancer (mCRC) patients are predisposed to venous thromboembolism (VTE). This study aimed to (1) evaluate the efficacy of 4 existing cancer-specific VTE models in predicting VTE incidence among hospitalized mCRC patients, and (2) examine the influence of incorporating mCRC molecular subtypes into these models. We conducted an evaluation of 4 cancer-specific VTE models, including Khorana, Vienna CATS, Protecht, and CONKO in a dataset involving 1392 mCRC patients. To evaluate the predictive performance, we utilized receiver operating characteristic (ROC) curves for both the original models and the modified models that incorporated microsatellite instability status or KRAS/NRAS/BRAF mutations. Moreover, we computed the net reclassification improvement (NRI) to quantify the enhancements made to the modified VTE risk models. All models demonstrated a moderate area under the ROC curve (ROC-AUC) when predicting the occurrence of VTE: Khorana (0.550), Vienna CATS (0.671), Protecht (0.652), and CONKO (0.578). The incorporation of KRAS and BRAF mutations significantly improved the ROC-AUC of all 4 existing models (modified Khorana: 0.796, modified Vienna CATS: 0.832, modified Protecht: 0.834, and modified CONKO: 0.809). After dichotomizing the risk using a threshold of 3 points and comparing them with the original models, NRI values for the 4 modified models were 0.97, 0.95, 1.11, and 0.98, respectively. All 4 cancer-specific VTE models exhibit moderate performance when identifying mCRC patients at high risk of VTE. Incorporating KRAS and BRAF mutations may enhance the prediction of VTE in hospitalized mCRC patients.

Benefit-Risk Assessment of Rivaroxaban for Extended Thromboprophylaxis After Hospitalization for Medical Illness

Background Venous thromboembolism (VTE) often occurs after hospitalization in medically ill patients, but the population benefit-risk of extended thromboprophylaxis remains uncertain. Methods and Results The MARINER (Medically Ill Patient Assessment of Rivaroxaban Versus Placebo in Reducing Post-Discharge Venous Thrombo-Embolism Risk) study (NCT02111564) was a randomized double-blind trial that compared thromboprophylaxis with rivaroxaban 10 mg daily versus placebo for 45 days after hospital discharge in medically ill patients with a creatinine clearance ≥50 mL/min. The benefit-risk balance in this population was quantified by calculating the between-treatment rate differences in efficacy and safety end points per 10 000 patients treated. Clinical characteristics of the study population were consistent with a hospitalized medical population at risk for VTE. Treating 10 000 patients with rivaroxaban resulted in 32.5 fewer symptomatic VTE and VTE-related deaths but was associated with 8 additional major bleeding events. The treatment benefit was driven by the prevention of nonfatal symptomatic VTE (26 fewer events). There was no between-treatment difference in the composite of critical site or fatal bleeding. Conclusions Extending thromboprophylaxis with rivaroxaban for 45 days after hospitalization provides a positive benefit-risk balance in medically ill patients at risk for VTE who are not at high risk for bleeding. Registration URL: https://clinicaltrials.gov/; Unique identifier: NCT02111564.

State-of-the-art-mini review: Dual pathway inhibition to reduce arterial and venous thromboembolism

Venous thromboembolism (VTE) and arterial thromboembolism (ATE) are linked by the common mechanism of thrombin generation. Historically these entities have been treated as separate pathophysiologic processes requiring different treatments: VTE, as the formation of fibrin-/coagulation-factor-derived thrombus in low flow vasculature, requiring anticoagulants; versus ATE, as largely platelet-derived thrombus in high flow vasculature, requiring antiplatelet agents. Observational studies have elucidated shared risk factors and co-morbidities predisposing individuals with VTE to ATE, and vice versa, and have bolstered the strategy of dual pathway inhibition (DPI) – the combination of low dose anticoagulants with antiplatelet agents – to reduce thrombotic outcomes on both sides of the vasculature. Randomized clinical trials have evaluated the efficacy and safety of such regimens - mostly rivaroxaban and aspirin - in high-risk groups of patients, including those with recent acute or chronic coronary syndrome, as well as those with peripheral artery disease with or without revascularization. Studies of extended VTE prophylaxis in acutely ill medical patients have also contributed to the evidence evaluating DPI. The totality of available data supports the concept that DPI can reduce major and fatal thromboembolic outcomes, including stroke, myocardial infarction, VTE, and cardiovascular death in key patient cohorts, with acceptable risk of bleeding. Further data are needed to refine which patients derive the best net clinical benefit from such an approach. At the same time, other novel agents such as contact pathway inhibitors that reduce thrombin generation without affecting hemostasis - and thus maximize safety - should be assessed in appropriate populations.

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.

Benefit-Risk of Rivaroxaban for Extended Thromboprophylaxis After Hospitalization for Medical Illness: Pooled Analysis From MAGELLAN and MARINER

Background

Thromboprophylaxis extended after hospital discharge in medically ill patients currently is not recommended by practice guidelines because of uncertainty about the benefit for preventing major or fatal thromboembolic events, and the risk of bleeding.

Methods and Results

We assessed the benefit and risk of thromboprophylaxis with rivaroxaban 10 mg once daily extended for 25 to 45 days after hospitalization for preventing major thromboembolism in medically ill patients using the pooled data in 16 496 patients from 2 randomized trials, MARINER (Medically Ill Patient Assessment of Rivaroxaban Versus Placebo in Reducing Post‐Discharge Venous Thrombo‐Embolism Risk) and MAGELLAN (Multicenter, randomized, parallel‐group efficacy and safety study for the prevention of venous thromboembolism in hospitalized medically ill patients comparing rivaroxaban with enoxaparin). The data from the MARINER trial were pooled with the data from the MAGELLAN trial in patients who were free of thrombotic or bleeding events up to the last dose of enoxaparin/placebo and who continued in the outpatient phase of thromboprophylaxis. The composite outcome of major thromboembolic events (symptomatic deep vein thrombosis, nonfatal pulmonary embolism, myocardial infarction, and nonhemorrhagic stroke) and all‐cause mortality was used to assess benefit and was compared with the risk of the composite of fatal and critical site bleeding. The incidence of the composite efficacy outcome was 1.80% (148 of 8222 patients) in the rivaroxaban group, compared with 2.31% (191 of 8274 patients in the placebo group) (HR, 0.78 [95% CI, 0.63–0.97], P=0.024). Fatal or critical site bleeding events were infrequent and occurred in <0.1% of patients in both groups (rivaroxaban 0.09%; placebo 0.04%; HR, 2.36; P=0.214).

Conclusions

The results suggest a benefit for reducing major thromboembolic outcomes (number needed to treat: 197), with a favorable trade‐off to fatal or critical site bleeding (number needed to harm: 2045).

Registration

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT00571649 and NCT02111564.

[Pharmacological Thromboprophylaxis in Acutely Ill Hospitalized Medical Patients]

Venous thromboembolic events (VTE) occur in approximately 50% of cases during or following hospitalization; VTE are a major cause of morbidity and mortality. Thromboprophylaxis for 6 to 14 days with heparins or fondaparinux has been demonstrated to be effective in VTE prevention in patients hospitalized for acute medical illnesses and reduced mobility. Nevertheless, the level of recommendation has been gradually downgraded as the benefit has been mainly demonstrated on the basis of systematic imaging diagnosed events. Direct oral anticoagulants have been assessed only as an extended prophylaxis, and are currently not recommended in medical thromboprophylaxis. Assessing the risk of VTE and bleeding in medical patients is complex. VTE and bleeding risk assessment scores were constructed but have not been validated. In order to improve the adequacy of prescriptions for thromboprophylaxis, the impact of different interventions has been the subject of several studies but these yielded varying results. The aim of this review is to analyze the indications for thromboprophylaxis in a medical setting with the latest available data.

An evaluation of venous thromboembolism by whole-body enhanced CT scan for critical COVID-19 pneumonia with markedly rises of coagulopathy related factors: a case series study

Background

Coronavirus disease (COVID-19) pneumonitis associated with severe respiratory failure has a high mortality rate. Based on recent reports, the most severely ill patients present with coagulopathy, and disseminated intravascular coagulation (DIC)-like massive intravascular clot formation is frequently observed. Coagulopathy has emerged as a significant contributor to thrombotic complications. Although recommendations have been made for anticoagulant use for COVID-19, no guidelines have been specified.

Case summary

We describe four cases of critical COVID-19 with thrombosis detected by enhanced CT scan. The CT findings of all cases demonstrated typical findings of COVID-19 and pulmonary embolism or deep venous thrombus without critical exacerbation. Two patients died of respiratory failure due to COVID-19.

Discussion

Previous reports have suggested coagulopathy with thrombotic signs as the main pathological feature of COVID-19, but no previous reports have focused on coagulopathy evaluated by whole-body enhanced CT scan. Changes in hemostatic biomarkers, represented by an increase in D-dimer and fibrin/fibrinogen degradation products, indicated that the essence of coagulopathy was massive fibrin formation. Although there were no clinical symptoms related to their prognosis, critical COVID-19-induced systemic thrombus formation was observed.

Conclusions

Therapeutic dose anticoagulants should be considered for critical COVID-19 because of induced coagulopathy, and aggressive follow-up by whole body enhanced CT scan for systemic venous thromboembolism (VTE) is necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00280-z.

Venous Thromboembolism Risk and Thromboprophylaxis Assessment in Surgical Patients Based on Caprini Risk Assessment Model

PURPOSE

Venous thromboembolism (VTE) is the most common preventable cause of hospitalization-associated mortality. In the absence of optimal prophylaxis and depending on the type of surgery and patient-related factors, the risk of developing VTE increases by 10% to 50%. We aimed to assess VTE risk and thromboprophylaxis among surgical patients hospitalized at surgical wards of Tikur Anbessa Specialized Hospital (TASH). Addis Ababa, Ethiopia.

MATERIALS AND METHODS

A retrospective cross-sectional study was conducted from September 1, 2018 to February 28, 2019. Data were collected using a pretested observational checklist which is prepared based on the VTE Caprini risk assessment model. Then, the collected data were checked for completeness and finally entered and analyzed using Statistical Package for Social Sciences (SPSS) version 25.

RESULTS

Out of 155 admitted patients, almost equal numbers of males (49.68%) and females (50.32%) participated in the study with a mean age of 41.87±16.84 and an age range of 13 to 89 years. Undergoing major surgery, resting in bed for more than 3 days and having acute infections (including pneumonia) were the most frequently seen VTE risk factors. Most of the study participants (135, 87.10%) were at risk of developing VTE (>1 Caprini risk score), and 47.11% were in the highest risk category (≥5 Caprini score). The maximum and minimum total risk scores were 19 and 1, respectively with a mean score of 4.53±2.31. Among patients who were at risk of developing VTE and eligible for thromboprophylaxis, only 17.78% received thromboprophylaxis and two ineligible patients received prophylaxis. Parental unfractionated heparin twice or three times per day was the most widely used thromboprophylaxis regimen. A total of 29 (18.71%) patients had one or more contraindication(s) for thromboprophylaxis and three of them took prophylaxis despite the contraindications. Only 3 (1.93%) patients admitted to surgical wards developed VTE during hospitalization.

CONCLUSION

As per the Caprini risk assessment model, the majority of surgical patients treated at TASH were at risk of developing VTE. However, thromboprophylaxis was underutilized. The incidence of VTE was 1.93% in our study.

Postdischarge thrombosis and hemorrhage in patients with COVID-19

Coronavirus disease 2019 (COVID-19) is associated with a prothrombotic state with a high incidence of thrombotic events during hospitalization; however, data examining rates of thrombosis after discharge are limited. We conducted a retrospective observational cohort study of discharged patients with confirmed COVID-19 not receiving anticoagulation. The cohort included 163 patients with median time from discharge to last recorded follow-up of 30 days (interquartile range [IQR], 17-46 days). The median duration of index hospitalization was 6 days (IQR, 3-12 days) and 26% required intensive care. The cumulative incidence of thrombosis (including arterial and venous events) at day 30 following discharge was 2.5% (95% confidence interval [CI], 0.8-7.6); the cumulative incidence of venous thromboembolism alone at day 30 postdischarge was 0.6% (95% CI, 0.1-4.6). The 30-day cumulative incidence of major hemorrhage was 0.7% (95% CI, 0.1-5.1) and of clinically relevant nonmajor bleeds was 2.9% (95% CI, 1.0-9.1). We conclude that the rates of thrombosis and hemorrhage appear to be similar following hospital discharge for COVID-19, emphasizing the need for randomized data to inform recommendations for universal postdischarge thromboprophylaxis.

Factors Influencing Prescribers' Decision for Extending Venous Thromboembolism Prophylaxis in the Medical Patient Population following Hospitalization

Introduction  Venous thromboembolism (VTE) prophylaxis during hospitalization has clearly defined metrics for risk stratification and practice policy employed to ensure processes of adherence. However, acceptance for practice or even the level and timeline of risk is less clear during the immediate time after hospitalization. With emerging new oral anticoagulant agents, data are available that may influence prescribing in the outpatient setting following hospitalization. A survey was created to determine the level of acceptance or influences for practice surrounding continuation of anticoagulation following hospitalization.

Methods  This study was designed as a single-center survey of hospitalist and family medicine physician to assess influences to the physician's impression for risk of VTE prophylaxis and knowledge of therapy options.

Results  Physicians reported depending heavily on medical center protocols for determining anticoagulation at hospital discharge. Prescribing postdischarge anticoagulation was reported to be affected by lack of comfort with prescribing oral medications and concerns with risk of bleeding for all types of anticoagulation outweighing the perceived benefit. Additionally, the decision whether to prescribe these medications at discharge was reported to be related to perceived cost and other patient barriers such as concerns over route of administration.

Conclusion  Concerns for bleeding were an influence and likely resulted in shorter duration for VTE prophylaxis being prescribed posthospitalization.

Predictability of CRP and D-Dimer levels for in-hospital outcomes and mortality of COVID-19

Background

Systemic inflammation elicited by a cytokine storm is considered a hallmark of coronavirus disease 2019 (COVID-19). This study aims to assess the clinical utility of the C-reactive protein (CRP) and D-Dimer levels for predicting in-hospital outcomes in COVID-19.

Methods

A retrospective cohort study was performed to determine the association of CRP and D-Dimer with the need for invasive mechanical ventilation (IMV), dialysis, upgrade to an intensive care unit (ICU) and mortality. Independent t-test and multivariate logistic regression analysis were performed to calculate mean differences and adjusted odds ratios (aOR) with its 95% confidence interval (CI), respectively.

Results

A total of 176 patients with confirmed COVID-19 diagnosis were included. On presentation, the unadjusted odds for the need of IMV (OR 2.5, 95% CI 1.3-4.8, p = 0.012) and upgrade to ICU (OR 3.2, 95% CI 1.6-6.5, p = 0.002) were significantly higher for patients with CRP (>101 mg/dl). Similarly, the unadjusted odds of in-hospital mortality were significantly higher in patients with high CRP (>101 mg/dl) and high D-Dimer (>501 ng/ml), compared to corresponding low CRP (<100 mg/dl) and low D-Dimer (<500 ng/ml) groups on day-7 (OR 3.5, 95% CI 1.2-10.5, p = 0.03 and OR 10.0, 95% CI 1.2-77.9, p = 0.02), respectively. Both high D-Dimer (>501 ng/ml) and high CRP (>101 mg/dl) were associated with increased need for upgrade to the ICU and higher requirement for IMV on day-7 of hospitalization. A multivariate regression model mirrored the overall unadjusted trends except that adjusted odds for IMV were high in the high CRP group on day 7 (aOR 2.5, 95% CI 1.05-6.0, p = 0.04).

Conclusion

CRP value greater than 100 mg/dL and D-dimer levels higher than 500 ng/ml during hospitalization might predict higher odds of in-hospital mortality. Higher levels at presentation might indicate impending clinical deterioration and the need for IMV.

Extended Venous Thromboembolism Prophylaxis in Medically Ill Patients: An NATF Anticoagulation Action Initiative

Hospitalized patients with acute medical illnesses are at risk for venous thromboembolism (VTE) during and after a hospital stay. Risk factors include physical immobilization and underlying pathophysiologic processes that activate the coagulation pathway and are still present after discharge. Strategies for optimal pharmacologic VTE thromboprophylaxis are evolving, and recommendations for VTE prophylaxis can be further refined to protect high-risk patients after hospital discharge. An early study of extended VTE prophylaxis with a parenteral agent in medically ill patients yielded inconclusive results with regard to efficacy and bleeding. In the Acute Medically Ill VTE Prevention with Extended Duration Betrixaban (APEX) trial, extended use of betrixaban halved symptomatic VTE, decreased hospital readmission, and reduced stroke and major adverse cardiovascular events compared with standard enoxaparin prophylaxis. Based on findings from APEX, the Food and Drug Administration approved betrixaban in 2017 for extended VTE prophylaxis in acute medically ill patients. In the Reducing Post-Discharge Venous Thrombo-Embolism Risk (MARINER) study, extended use of rivaroxaban halved symptomatic VTE in high-risk medical patients compared with placebo. In 2019, rivaroxaban was approved for extended thromboprophylaxis in high-risk medical patients, thus making available a new strategy for in-hospital and post-discharge VTE prevention. To address the critical unmet need for VTE prophylaxis in medically ill patients at the time of hospital discharge, the North American Thrombosis Forum (NATF) is launching the Anticoagulation Action Initiative, a comprehensive consensus document that provides practical guidance and straightforward, patient-centered recommendations for VTE prevention during hospitalization and after discharge.

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.

Recommendations for VTE Prophylaxis in Medically Ill Patients

Venous thromboembolism (VTE) remains highly prevalent in medically ill patients, and often leads to increased mortality and cost burden during hospitalization and post-discharge. Nearly half of all VTEs occur during or after hospitalization, with pulmonary embolism accounting for 10% of inpatient mortality. Appropriate prophylaxis in high-risk medically ill patients has been shown to reduce risk of VTE and related mortality. Despite current evidence-based guidelines, VTE prophylaxis has been under-used. This owes greatly to ambiguity and concerns related to appropriate patient and prophylactic agent selection, and duration of prophylaxis. Because many acutely ill medical patients have multiple comorbidities, the risk of major bleeding must be considered when choosing to implement pharmacological VTE prophylaxis. Multiple risk assessment models have been developed and validated to help estimate VTE and bleeding risks in this population. While studies have shown that the risk for VTE often extends far beyond hospital discharge, there is no evidence to support extending prophylaxis after hospital discharge. The appropriate selection of VTE prophylaxis requires consideration for cost, availability, patient preference, compliance, and underlying comorbidities. Our paper reviews the current evidence and reasoning for appropriate selection of VTE prophylaxis in acutely medical ill patients, and highlights our own approach and recommendations.

Reassessment of venous thromboembolism and bleeding risk in medical patients receiving VTE prophylaxis

RATIONALE, AIMS, AND OBJECTIVES

The majority of hospitalized nonsurgical medical patients receive pharmacological prophylaxis for venous thromboembolism (VTE), and reassessment of changes in thrombosis and bleeding risk factors during hospital admission may represent an opportunity to discontinue unnecessary or unsafe therapy. The use of validated, clinically derived risk assessment models (RAMs) represents a shift towards an individualized, patient-centred approach to VTE prophylaxis. We are interested in using these tools to assess whether risk categories for VTE and bleeding change during admission and to assess whether such changes result in discontinuation of prophylaxis. Our primary objective was to determine whether VTE and bleed risk categories changed during the course of admission to warrant discontinuation of VTE prophylaxis, using the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE and Bleed RAMs, respectively. Secondary objectives were to determine the number of patients whose risk categorizations for VTE and bleeding warranted discontinuation of VTE prophylaxis and to survey whether prophylaxis was continued or discontinued.

METHODS

A retrospective review was undertaken for a cross-sectional, randomly selected sample of patients who received VTE prophylaxis while admitted to medical wards in a collection of regional hospitals.

RESULTS

Of the 351 medical records reviewed, only eight patients (2.3%) changed their VTE risk category and six (1.7%) changed their bleed risk category to warrant discontinuation of VTE prophylaxis. Ninety patients (26%) were at high risk of VTE and low risk of bleed throughout admission, warranting continued VTE prophylaxis. The majority of patients remained at low risk of VTE throughout admission but remained on VTE prophylaxis until discharge.

CONCLUSIONS

Risk categories for VTE and bleeding for medical patients did not appreciably change throughout hospital admission. Use of VTE RAMs at admission and prior to initiation of therapy should reduce unnecessary prophylaxis in the majority of medical patients who are at low risk of VTE.

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.

Frequency of hospital readmissions for venous thromboembolism and associated hospital costs and length of stay among acute medically ill patients in the US

Objectives: This study evaluated the frequency of hospital readmissions for venous thromboembolism (VTE) and the associated costs and length of stay (LOS) among acute medically ill patients in the US using a real-world claims database analysis. Methods: Patients (≥40 years of age) at risk of VTE due to hospitalization for acute medical illnesses, based on primary hospital discharge diagnosis codes, were identified from the MarketScan databases between July 1, 2011 and March 31, 2015. Patients were required to have continuous insurance enrollment in the 6 months prior to initial (index) hospitalizations (baseline period) and in the 6 months after hospital discharge (follow-up period). The proportions of patients with VTE-related (diagnosis at any position) and VTE as primary diagnosis hospital readmissions during the follow-up period were evaluated. The associated costs and LOS for such readmissions were also determined, as well as time to VTE-related readmissions. Results: Of the study population (n = 12,785; mean age = 68.3 years), most were hospitalized primarily for infectious diseases (35.2%), followed by respiratory diseases (27.9%), cancer (15.7%), heart failure (11.8%), ischemic stroke (8.1%), and rheumatic diseases (1.4%). Of the overall study population, 2.1% (n = 268) had a VTE-related hospital readmission in the 6 months following discharge of their index hospitalization, of which 36.6% (n = 98) were for a primary diagnosis of VTE. Approximately 25.4% of the VTE-related hospital readmissions occurred within the first 30 days of discharge and 58.2% within 90 days. The mean cost for a hospital readmission with a primary diagnosis of VTE was $18,681 (mean LOS = 5.0 days); for readmissions with a primary diagnosis of DVT and PE, mean costs were $14,719 and $23,305, respectively. Conclusions: Among this study population of patients hospitalized for acute medical illnesses, some experienced a VTE event requiring re-hospitalization, with 25% occurring within the first 30 days after hospital discharge.

Prothrombotic fibrin clot properties are associated with post-discharge venous thromboembolism in acutely ill medical patients

INTRODUCTION

Reduced clot permeability and lysability have been reported in patients who experienced venous thromboembolism (VTE) following lower limb injury despite pharmacological thromboprophylaxis. We hypothesized that similarly altered fibrin clot properties characterize patients with post-discharge VTE despite thromboprophylaxis during prior hospitalization due to acute medical illnesses.

METHODS

In a case-control study, we assessed 48 patients who developed VTE within 4 weeks post-discharge despite pharmacological thromboprophylaxis during hospitalization (the thromboprophylaxis group) and three age- and sex-matched control groups (n = 48 each): (1) patients who developed VTE following hospitalization without pharmacological thromboprophylaxis (the no-thromboprophylaxis group), (2) patients with unprovoked VTE and (3) individuals without history of VTE (the no-VTE group). Blood samples were obtained following ≥3 months of anticoagulation in VTE patients. Fibrin clot properties, thrombin generation and fibrinolysis activators and inhibitors were assessed.

RESULTS

Compared with the no-VTE group, the thromboprophylaxis group formed denser fibrin networks reflected by lower clot permeability (K_s, -13%) and impaired fibrinolysis, as evidenced by prolonged clot lysis time (CLT, +14%) and lower rate of D-dimer release from clots (D-D_rate, -9%) accompanied by elevated high-sensitivity C-reactive protein (hsCRP, +79%), peak thrombin generation (+55%) and α₂-antiplasmin (+10%, all p < 0.05). Similar fibrin clot features were observed following unprovoked VTE. The thromboprophylaxis group had also lower K_s (-13%), elevated α₂-antiplasmin (+18%) and higher peak thrombin generation (+25%, all p < 0.05) as compared with the no-thromboprophylaxis group.

CONCLUSIONS

Unfavorably altered plasma clot properties and increased thrombin generation characterize medical patients with post-discharge VTE despite receiving pharmacological thromboprophylaxis during hospitalization for acute conditions.

Budget impact analysis of betrixaban for venous thromboembolism prophylaxis in nonsurgical patients with acute medical illness in the United Kingdom

OBJECTIVES

Venous thromboembolism (VTE) incurs substantial costs to the UK National Health Service (NHS). Betrixaban is approved in the US for VTE prophylaxis with a recommended 35-42 days of treatment. This analysis modeled the budget impact of introducing betrixaban for extended-duration VTE prophylaxis in nonsurgical patients with acute medical illness at risk of VTE in the UK, where it is not yet licensed.

METHODS

The 5-year budget impact of introducing betrixaban into current prophylaxis (low molecular weight heparin and fondaparinux) was estimated for the UK NHS. The Phase 3 APEX study provided primary event (VTE, myocardial infarction, ischemic stroke, and death; all-cause or VTE-related) and treatment complications data. Literature informed risk of recurrent events and long-term complications, population, market share, and costs for treatment and management of events. Network meta-analyses informed symptomatic DVT, pulmonary embolism and VTE-related death rates in fondaparinux patients. Deterministic sensitivity analyses explored uncertainty.

RESULTS

Introducing betrixaban accrued savings of £1,290,000-£23,000,000 in years 1-5. Savings were from reduced primary VTE events, which reduced recurrent events and future complications. All sensitivity analyses showed savings.

CONCLUSION

Introducing extended-duration VTE prophylaxis with betrixaban in the UK would accrue substantial savings annually over the next 5 years compared to current prophylaxis. Clinical trial registration: www.clinicaltrials.gov identifier is NCT01583218.

Influence of the duration of hospital length of stay on frequency of prophylaxis and risk for venous thromboembolism among patients hospitalized for acute medical illnesses in the USA

Background

We evaluated whether the duration of hospital stay influences venous thromboembolism (VTE) prophylaxis patterns and VTE risk during hospitalization and post-discharge among patients hospitalized for acute illnesses in the USA.

Methods

Patients hospitalized for acute illnesses were identified from the US MarketScan Commercial and Medicare databases (January 1, 2012–June 30, 2015). Patients were stratified by index hospital length of stay (LOS), with study groups with 1–3 day, 4–6 day, and ≥7 day LOSs. Use of VTE prophylaxis and VTE event rates during and after hospitalization (6-month follow-up) were evaluated.

Results

Of the overall population, 8647 had a 1–3 day LOS, 5551 had a 4–6 day LOS, and 3697 had a ≥7 day LOS. A greater proportion of patients with a 1–3 day LOS (66.2%) did not receive any VTE prophylaxis in comparison to patients with a 4–6 day LOS (55.0%) and ≥7 day LOS (48.8%; p<0.001). Proportions of patients with VTE events during the index hospitalization increased with longer hospital LOS (1–3 day LOS: 0.5%; 4–6 day LOS: 1.3%; ≥7 day LOS: 5.4%), as did proportions of patients with VTE events during the 6-month follow-up (1–3 day LOS: 2.4%; 4–6 day LOS: 2.7%; ≥7 day LOS: 4.2%).

Conclusion

Among this study population of hospitalized acutely ill patients in the USA, VTE pharmacologic prophylaxis was underutilized, regardless of the duration of hospital stay. However, the risk for VTE events was substantial, with nearly 10% of those with a ≥7 day LOS having suffered a VTE event within 6 months.

Improvement of appropriate pharmacological prophylaxis in hospitalised cancer patients with a multiscreen e-alert system: a single-centre experience

PURPOSE

Thromboprophylaxis use among medical inpatients, including cancer patients, is suboptimal. We aimed to evaluate the impact of a novel multiscreen version (v2.0) of an e-alert system for VTE prevention in hospitalised cancer medical patients compared to the original software.

METHODS

Prospective study including 989 consecutive adult cancer patients with high-risk of VTE. Patients were followed-up 30 days post-discharge. Two periods were defined, according to the operative software.

RESULTS

E-alert v2.0 was associated with an increase in the use of LMWH prophylaxis (65.5% vs. 72.0%); risk difference (95% CI) 0.064 (0.0043-0.12). Only 16% of patients in whom LMWH prophylaxis was not prescribed lacked a contraindication. No significant differences in the rates of VTE (2.9% vs. 3.2%) and major bleeding (2.7% vs. 4.0%) were observed.

CONCLUSIONS

E-alert v2.0 further increased the use of appropriate thromboprophylaxis in hospitalised cancer patients, although was not associated with a reduction in VTE incidence.

Updated clinical models for VTE prediction in hospitalized medical patients

Venous thromboembolism (VTE) occurring in hospitalized medical patients is associated with increased length of hospitalization, high rate of acute care hospital transfer, longer inpatient rehabilitation and multiplication of health-care costs. Identification of acutely ill hospitalized medical patients eligible for thromboprophylaxis is a sophisticated process. Global VTE risk stems from the combination of predictors related with the acute medical illness, comorbidities, associated treatments and patients' intrinsic risk factors. Emerging clinical risk factors related to underlying pathologies should be considered when VTE risk is assessed. The Padua Prediction Score (PPS), the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE-RAM) and the Geneva Risk Score are three robust risk assessment models (RAM) which underwent extensive external validation in cohorts of acutely ill hospitalized medical patients. The development of the IMPROVE bleeding risk assessment model and the identification of D-Dimer increase as a biomarker-predictor of VTE are some steps forward for personalized thromboprophylaxis. The beneficial impact of the RAMs in VTE prevention is already seen by the decrease of in-hospital VTE rates when RAMs are incorporated in electronic alert systems.

Association of Anemia with Venous Thromboembolism in Acutely Ill Hospitalized Patients: An APEX Trial Substudy

BACKGROUND

Anemia is a common finding and independent predictor for adverse outcomes in hospitalized patients with medical illness. It remains unclear whether anemia is a risk factor for venous thromboembolism and whether the presence of anemia can refine risk assessment for prediction of venous thromboembolism, thereby adding incremental utility to a validated model.

METHODS

In the Acute Medically Ill Venous Thromboembolism Prevention with Extended Duration Betrixaban trial (APEX), 7513 hospitalized medical patients were randomized to receive either betrixaban or standard-of-care enoxaparin for thromboprophylaxis. Baseline hemoglobin concentrations were obtained in 6861 patients, with a follow-up of 77 days. Symptomatic venous thromboembolism events, including symptomatic deep vein thrombosis, pulmonary embolism, and venous thromboembolism-related mortality, were compared between low-hemoglobin and normal-hemoglobin groups (normal range: 12.5-17.0 g/dL for males and 11.0-15.5 g/dL for females). The relationship between anemia and venous thromboembolism events was assessed by fitting a univariable and multivariable logistic regression model composed of thromboprophylaxis and risk factors. Venous thromboembolism risk refinement by hemoglobin measurement was evaluated in the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) risk assessment model.

RESULTS

Low hemoglobin at baseline was associated with a greater risk of symptomatic venous thromboembolism (relative risk [RR] 1.94 [95% confidence interval, 1.27-2.98]; P = .002), symptomatic deep vein thrombosis (RR 2.29 [1.12-4.68]; P = .019), and nonfatal pulmonary embolism (RR 2.63 [1.22-5.65]; P = .010) but not venous thromboembolism-related mortality (RR 1.47 [0.71-3.04]; P = .30). After adjusting for thromboprophylaxis, history of previous venous thromboembolism, intensive or coronary unit admission, and D-dimer, low hemoglobin (as a categorical or continuous variable) remained associated with an increased likelihood of venous thromboembolism (adjusted odds ratio 1.71 [95% confidence interval, 1.09-2.69]; P = .020). Low hemoglobin also improved risk discrimination and reclassification after inclusion in the IMPROVE model.

CONCLUSIONS

Anemia was independently associated with a greater risk of symptomatic venous thromboembolism among acutely ill medical patients despite the provision of thromboprophylaxis. Hemoglobin measurement also improved risk stratification by the IMPROVE venous thromboembolism risk score.

Effect of Thrombophilic Factors on Renal Graft Function: A Single-Center Experience

BACKGROUND

Optimization of immunosuppressive therapy reduced the incidence of acute rejection, and therefore vascular complications, including graft thrombosis, which have emerged as the main cause of graft loss in the early post-transplant period. A thrombophilic condition may lead to renal graft loss. The aim of the study was to assess renal graft function in thrombophilic renal recipients receiving anticoagulation treatment.

METHODS

This is a retrospective study including 29 renal recipients (ktx group) with a history of thrombosis and confirmed thrombophilic factor. Graft function was evaluated by median serum creatinine concentration at the third month after ktx (SCr₁) and at the end of the observation (SCr₂) with respect to hypercoagulability (factor V Leiden [FVL], mutation G20210A, antiphospholipid antibodies, deficiency of protein S [PS] or C [PC], factor VIII >200%).

RESULTS

Recipients underwent retransplantation because of graft thrombosis (P < .001). They more often underwent urgent transplantation (P = .008), received induction therapy (P = .021), underwent an indication other than protocol biopsy (P = .001), or experienced acute rejection (P = .042). Differences in graft function (SCr₂) were found at the end of observation (ktx group vs controls 1.9 mg/dL vs 1.3 mg/dL, respectively, P = .014). Multivariate analysis revealed inferior thrombophilic graft function in the model with SCr₁ <2 mg/dL (odds ratio 0.07, 95% confidence interval 0.01-0.57, P = .014) and in the model with SCr₂ <2 mg/dL (odds ratio 0.15; 95% confidence interval 0.04-0.54, P = .004). The incidence of antiphospholipid syndrome was 31%; FVIII, 31%; FVL, 24.1%; and PC/PS, 13.8%. After anticoagulation was introduced no thromboembolic events or bleeding complications occurred.

CONCLUSION

Hypercoagulability is not a contraindication to ktx but may worsen graft function. Post-transplant care in thrombophilic recipients is demanding (retransplantation, immunization, protocol biopsy, anticoagulation), but is the only means by which to maintain a graft.

Assessment of the Risk of Venous Thromboembolism in Medical Inpatients using the Padua Prediction Score and Caprini Risk Assessment Model

Aim: The optimal risk assessment model (RAM) to stratify the risk of venous thromboembolism (VTE) in medical inpatients is not known. We examined and compared how well the Padua Prediction Score (PPS) and the Caprini RAM stratify VTE risk in medical inpatients.

Methods: We undertook a retrospective case-control study among medical inpatients admitted to a large general hospital in China during a 4-year period. In total, 902 cases were confirmed to have VTE during hospitalization and 902 controls were selected randomly to match cases by medical service.

Results: The VTE risk increased significantly with an increase of the cumulative PPS or Caprini RAM score. A PPS and Caprini RAM “high risk” classification was, respectively, associated with a 5.01-fold and 4.10-fold increased VTE risk. However, the Caprini RAM could identify 84.3% of the VTE cases to receive prophylaxis according to American College of Chest Physicians guidelines, whereas the PPS could only identify 49.1% of the VTE cases. In the medical inpatients studied, five risk factors seen more frequently in VTE cases than in controls in the Caprini RAM were not included in the PPS. The Caprini RAM risk levels were linked almost perfectly to in-hospital and 6-month mortality.

Conclusions: Both the PPS and Caprini RAM can be used to stratify the VTE risk in medical inpatients effectively, but the Caprini RAM may be considered as the first choice in a general hospital because of its incorporation of comprehensive risk factors, higher sensitivity to identify patients who may benefit from prophylaxis, and potential for prediction of mortality.

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.

A Test in Context: D-Dimer

D-dimer is a soluble fibrin degradation product that results from ordered breakdown of thrombi by the fibrinolytic system. Numerous studies have shown that D-dimer serves as a valuable marker of activation of coagulation and fibrinolysis. Consequently, D-dimer has been extensively investigated for the diagnosis of venous thromboembolism (VTE) and is used routinely for this indication. In addition, D-dimer has been evaluated for determining the optimal duration of anticoagulation in VTE patients, for diagnosing and monitoring disseminated intravascular coagulation, and as an aid in the identification of medical patients at high risk for VTE. Thus, quantification of D-dimer levels serves an important role in guiding therapy. This review: 1) describes how D-dimer is generated; 2) reviews the assays used for its detection; and 3) discusses the role of D-dimer determination in these various conditions.