International clinical practice guidelines including guidance for direct oral anticoagulants in the treatment and prophylaxis of venous thromboembolism in patients with cancer

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.

Rivaroxaban Versus Low-molecular-weight Heparin for Venous Thromboembolism in Advanced Upper Gastrointestinal Tract and Hepatopancreatobiliary Cancer

BACKGROUND/AIM

The aim of this study was to examine the efficacy and safety of direct oral anticoagulants for cancer-associated venous thromboembolism (VTE) in patients with active cancer.

PATIENTS AND METHODS

This study included patients with advanced unresectable/metastatic upper gastrointestinal (GI) or hepatopancreatobiliary (HPB) cancers with high risks of VTE and bleeding.

RESULTS

No significant differences were noted in potential bleeding factors between the rivaroxaban (n=105) and low-molecular-weight heparin (LMWH) (n=69) groups. Rivaroxaban exhibited similar risk of recurrent/aggravated VTE compared with LMWH (p=0.625) but increased risk of major bleeding (17.4% vs. 7.6%; p=0.072), clinically relevant bleeding (31.9% vs. 14.3%; p=0.019), and total bleeding (40.6% vs. 19%; p=0.010). The multivariate analysis regarded rivaroxaban as a significant factor for major bleeding (p=0.043) and clinically relevant bleeding (p=0.043).

CONCLUSION

Rivaroxaban exhibits comparable efficacy but increases bleeding risks compared with LMWH in patients with active unresectable/metastatic upper GI tract or HPB cancers, requiring extra caution of higher major bleeding risks.

Efficacy and safety of direct oral anticoagulants versus low-molecular-weight heparin in patients with cancer: a systematic review and meta-analysis

The efficacy and safety of direct oral anticoagulants (DOACs) versus low-molecular-weight heparin (LMWH) are still debated in the treatment of patients with cancer, and the optimal duration of therapy remains uncertain. Electronic databases (PubMed, Embase, and Cochrane Library) were searched to retrieve studies on the efficacy and safety of DOACs versus LMWH in treating patients with cancer from January 1980 to October 2018. The primary efficacy and safety endpoints were recurrent venous thromboembolism (VTE) and major bleeding. Our study included two randomized controlled trials (RCTs) and nine observational studies, together comprising 4509 patients with cancer. The pooled estimates indicated that DOACs led to a modest reduction recurrent VTE in the RCTs [RR: 0.63, 95% confidence interval (CI), 0.42-0.96, P = 0.03] and in the observational studies (RR: 0.74, 95% CI, 0.58-0.93, P = 0.011), without increasing the risk of major bleeding for observational studies (P = 0.805), but increased for RCTs (P = 0.017). The same trends were observed in the rivaroxaban subgroup. Moreover, subgroup analyses according to the treatment duration indicated that DOACs significantly reduced the incidence of recurrent VTE (P = 0.006 at 6 months; P < 0.001 at 12 months) without significant differences in major bleeding compared with LMWH at 6 or 12 months. Patients with cancer who received DOACs exhibited a significant reduction in recurrent VTE with no increased risk of major bleeding compared with LMWH. DOACs may be an alternative choice for long-term anticoagulant therapy in patients with cancer.

Primary Thromboprophylaxis in Ambulatory Cancer Patients: Where Do We Stand?

Venous thromboembolism (VTE), comprising deep-vein thrombosis and pulmonary embolism, is a frequent complication in ambulatory cancer patients. Despite the high risk, routine thromboprophylaxis is not recommended because of the high number needed to treat and the risk of bleeding. Two recent trials demonstrated that the number needed to treat can be reduced by selecting cancer patients at high risk for VTE with prediction scores, leading the latest guidelines to suggest such an approach in clinical practice. Yet, the interpretation of these trial results and the translation of the guideline recommendations to clinical practice may be less straightforward. In this clinically-oriented review, some of the controversies are addressed by focusing on the burden of VTE in cancer patients, discussing the performance of available risk assessment scores, and summarizing the findings of recent trials. This overview can help oncologists, hematologists, and vascular medicine specialists decide about thromboprophylaxis in ambulatory cancer patients.

Management of cancer-related thrombosis in the era of direct oral anticoagulants: A comprehensive review of the 2019 ITAC-CME clinical practice guidelines. On behalf of the Groupe Francophone Thrombose et Cancer (GFTC)

Venous thromboembolism (VTE) is a common disease complication in cancer patients and the second cause of death after cancer progression. VTE management and prophylaxis are critical in cancer patients, but effective therapy can be challenging because these patients are at higher risk of VTE recurrence and bleeding under anticoagulant treatment. Numerous published studies report inconsistent implementation of existing evidence-based clinical practice guidelines (CPG), including underutilization of thromboprophylaxis, and wide variability in clinical practice patterns across different countries and various practitioners. This review aims to summarize the 2019 ITAC-CME evidence-based CPGs for treatment and prophylaxis of cancer-related VTE, which include recommendations on the use of direct oral anticoagulants specifically in cancer patients. The guidelines underscore the gravity of developing VTE in cancer and recommend the best approaches for treating and preventing cancer-associated VTE, while minimizing unnecessary or over-treatment. Greater adherence to the 2019 ITAC guidelines could substantially decrease the burden of VTE and improve survival of cancer patients.

Cancer-Related Stroke: An Emerging Subtype of Ischemic Stroke with Unique Pathomechanisms

Systemic cancer and ischemic stroke are common conditions and two of the most frequent causes of death among the elderly. The association between cancer and stroke has been reported worldwide. Stroke causes severe disability for cancer patients, while cancer increases the risk of stroke. Moreover, cancer-related stroke is expected to increase due to advances in cancer treatment and an aging population worldwide. Because cancer and stroke share risk factors (such as smoking and obesity) and treatment of cancer can increase the risk of stroke (e.g., accelerated atherosclerosis after radiation therapy), cancer may accelerate conventional stroke mechanisms (i.e., atherosclerosis, small vessel disease, and cardiac thrombus). In addition, active cancer and chemotherapy may enhance thrombin generation causing stroke related to coagulopathy. Patients with stroke due to cancer-related coagulopathy showed the characteristics findings of etiologic work ups, D-dimer levels, and infarct patterns. In this review, we summarized the frequency of cancer-related stroke among patients with ischemic stroke, mechanisms of stroke with in cancer patients, and evaluation and treatment of cancer-related stroke. We discussed the possibility of cancer-related stroke as a stroke subtype, and presented the most recent discoveries in the pathomechanisms and treatment of stroke due to cancer-related coagulopathy.

Outcomes after venous thromboembolism in patients with gastric cancer: Analysis of the RIETE Registry

Gastric cancer is the fifth most common malignancy worldwide. Venous thromboembolism is an independent predictor of death among patients with gastric cancer. We aimed to describe the factors associated with mortality, thrombosis recurrence, and bleeding complications in patients with gastric cancer who develop venous thromboembolism. We included 612 patients with gastric cancer and venous thromboembolism in the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) registry from 2001 to 2018. We used Cox proportional hazard ratios and a Fine-Gray model to define factors associated with outcomes. The overall mortality at 6 months was 44.4%. Factors associated with increased 6-month mortality included immobility (HR 1.8, 95% CI 1.3-2.4; p < 0.001), anemia (HR 1.4, 95% CI 1.1-1.8; p < 0.02), and leukocytosis (HR 1.8, 95% CI 1.4-2.3; p < 0.001). Recurrent thrombosis occurred in 6.5% of patients and major bleeding complications in 8.5% of the cohort. Male sex was the main factor associated with thrombosis recurrence (HR 2.1, 95% CI 1.1-4.0; p < 0.02) and hemoglobin below 10 g/dL (HR 1.6, 95% CI 1.05-2.50; p = 0.03) the main factor associated with bleeding. In conclusion, patients with gastric cancer who develop venous thrombosis have a very high likelihood of death. Low hemoglobin in this population is associated with poor outcomes.

The "Janus Face" of Platelets in Cancer

Besides their vital role in hemostasis and thrombosis, platelets are also recognized to be involved in cancer, where they play an unexpected central role: They actively influence cancer cell behavior, but, on the other hand, platelet physiology and phenotype are impacted by tumor cells. The existence of this platelet-cancer loop is supported by a large number of experimental and human studies reporting an association between alterations in platelet number and functions and cancer, often in a way dependent on patient, cancer type and treatment. Herein, we shall report on an update on platelet-cancer relationships, with a particular emphasis on how platelets might exert either a protective or a deleterious action in all steps of cancer progression. To this end, we will describe the impact of (i) platelet count, (ii) bioactive molecules secreted upon platelet activation, and (iii) microvesicle-derived miRNAs on cancer behavior. Potential explanations of conflicting results are also reported: Both intrinsic (heterogeneity in platelet-derived bioactive molecules with either inhibitory or stimulatory properties; features of cancer cell types, such as aggressiveness and/or tumour stage) and extrinsic (heterogeneous characteristics of cancer patients, study design and sample preparation) factors, together with other confounding elements, contribute to “the Janus face” of platelets in cancer. Given the difficulty to establish the univocal role of platelets in a tumor, a better understanding of their exact contribution is warranted, in order to identify an efficient therapeutic strategy for cancer management, as well as for better prevention, screening and risk assessment protocols.

Multiple Myeloma and Thrombosis: Prophylaxis and Risk Prediction Tools

Thromboembolism in multiple myeloma (MM) patients remains a common complication that renders the optimization of our thromboprophylaxis practice necessary. This review aims to make clear the need for the development of more accurate risk assessment tools and means of thrombosis prevention. Current clinical practice is guided by available guidelines published by the IMWG in 2014, but the extent to which these are implemented is unclear. Recently, several groups developed clinical scores for thrombosis risk in MM in an attempt to improve risk stratification, but these have not been validated or used in clinical practice so far. Research in this field is increasingly focusing on understanding the unique coagulation profile of the MM patient, and data on potential biomarkers that accurately reflect hypercoagulability is emerging. Finally, promising evidence on the effectiveness of direct oral anticoagulants (DOACs) in the context of thrombosis prevention in MM patients is increasingly becoming available. The critical appraisal of the above research areas will establish the necessity of combining disease-specific clinical risk factors with coagulation biomarkers to allow more effective risk stratification that will eventually lead to the reduction of this significant complication. Results from ongoing clinical trials on the role of DOACs are much anticipated.

Anticoagulation in Deep Venous Thrombosis: Current Trends in the Era of Non- Vitamin K Antagonists Oral Anticoagulants

Anticoagulation therapy is the cornerstone of treatment in acute vein thrombosis (DVT) and it aims to reduce symptoms, thrombus extension, DVT recurrences, and mortality. The treatment for DVT depends on its anatomical extent, among other factors. Anticoagulation therapy for proximal DVT is clearly recommended (at least for 3 months), while AT for isolated distal DVT should be considered, especially in the presence of high thromboembolic risk factors. The optimal anticoagulant and duration of therapy are determined by the clinical assessment, taking into account the thromboembolic and bleeding risk in each patient in a case-by-case decision making. Non-Vitamin K antagonists oral anticoagulants (NOACs) were a revolution in the anticoagulation management of DVT. Nowadays, NOACs are considered as first-line therapy in the anticoagulation therapy for DVT and are recommended as the preferred anticoagulant agents by most scientific societies. NOACs offer a simple route of administration (oral agents), a rapid onset-offset of their action along with a good efficacy and safety profile in comparison with Vitamin K Antagonists (VKAs). However, there are issues about their efficacy and safety profile in specific populations with high thromboembolic and bleeding risks, such as renal failure patients, active-cancer patients, and pregnant women, in which VKAs and heparins were the standard care of treatment. Since the available data are promising for the use of NOACs in end-stage chronic kidney disease and cancer patients, several ongoing randomized trials are currently trying to solve that issues and give evidence about the safety and efficacy of NOACs in these populations.

Management of venous thromboembolism in cancer patients: Considerations about the clinical practice guideline update of the American society of clinical oncology

The American Society of Clinical Oncology (ASCO) recently updated their clinical practice guidelines. The most novel aspect of this update is represented by the introduction of DOACs as pharmacological options both for prophylaxis and treatment of VTE in patients with cancer. The heterogeneity of the cancer population in terms of type and stage of the malignancy, presence of comorbidities, and variability in cancer treatments and prognosis represent the major challenge of managing VTE in patients with cancer. The use of VTE prophylaxis is currently recommended in cancer patients admitted to the hospital for an acute illness or reduced mobility, but no sufficient information is available on the risk of bleeding during thromboprophylaxis. Concerning the thromboprophylaxis in ambulatory cancer patients receiving chemotherapy, further refinement of existing risk models or development of new models are needed for improving risk stratification to identify high-risk cancer patients. The updated ASCO guidelines recommend the use of DOACs (edoxaban and rivaroxaban) for treatment of VTE in patients with cancer. However, Major concerns on "real-life" use of DOACs in patients with cancer are highlighted especially for the bleeding risk in patients with gastrointestinal cancers and the potential drug-drug interactions with specific anticancer therapies. CONCLUSIONS: Uncertainties to the updated ASCO guidelines remain concerning a number of indications on prophylaxis and treatment due to the limited evidence available. These limitations determine the low strength of the recommendations. The ongoing studies will contribute to refine the best management of patients with cancer-associated VTE.

[Perioperative Venous Thromboembolism (VTE) Prophylaxis in Thoracic Cancer Patients: Chinese Experts Consensus - Interpretation of Application Prospect of Direct Oral Anticoagulant]

胸部恶性肿瘤患者围术期静脉血栓栓塞症（venous thromboembolism, VTE）是一种需要引起重视的胸外科围术期并发症，中国胸外科静脉血栓栓塞研究协作组针对胸部恶性肿瘤患者围术期VTE的预防，发布了国际首部《胸部恶性肿瘤围术期静脉血栓栓塞症预防中国专家共识》（2018版）。本文将对直接口服抗凝药在胸部恶性肿瘤患者围术期的应用进行解读，以助于更好地理解共识相关内容。

Development of a clinical prediction tool for cancer-associated venous thromboembolism (CAT): the MD Anderson Cancer Center CAT model

INTRODUCTION

Cancer-associated venous thromboembolism (CAT) is a major complication of malignancy. Our goal was to develop a prediction model for VTE that better represented to the population seen at large referral cancer centers.

MATERIALS AND METHODS

This study was nested in a prospective cohort study at the University of Texas MD Anderson Cancer Center that evaluated adult patients during outpatient cancer-staging computed tomography to estimate the prevalence of incidental VTE. Data from patients in whom incidental VTE was not found on initial CT were collected until 24 months ± 7 days from the study inclusion date to determine the occurrence of new VTE events. Demographics, clinical data, current cancer treatment information, and the use of erythropoietin stimulating agents (ESAs) along with hematologic variables were collected in all patients and analyzed to determine differences between those who developed VTE versus those who did not. All candidate variables with significance p value (≤ 0.1) under univariate analysis were considered to enter the final multivariate model.

RESULTS

Data of 548 patients were analyzed. The presence of metastatic disease and the use of platinum-based chemotherapy were strongly associated with CAT occurrence. The use of ESAs and specific malignancies showed trends of association with CAT, while associations were not statistically significant.Those characteristics were utilized to develop a clinical prediction model for CAT readily available and effective (c-index = 0.74).

CONCLUSION

Our model is effective and easy to incorporate in busy clinical settings and it does not depend on esoteric or difficult-to-obtain laboratory testing. Future external validation studies may provide further evidence for the applicability of our results.

What's new in the prevention and treatment of cancer-associated thrombosis?

Venous thromboembolism (VTE) is a common complication in ambulatory cancer patients receiving chemotherapy. Current clinical guidelines recommend against the use of routine primary thromboprophylaxis in unselected ambulatory cancer patients. The Khorana score is a risk assessment tool derived and prospectively validated for the identification of cancer patients at high risk of thrombotic complications. Recently, 2 randomized, controlled trials have assessed the use of low-dose direct oral Xa inhibitors, apixaban and rivaroxaban, for the prevention of cancer-associated thrombosis in ambulatory patients at intermediate to high risk of VTE (Khorana score ≥2). Taken together, these trials have shown that low-dose direct oral Xa inhibitors reduce the risk of VTE in this patient population without a significant increase in major bleeding. These results should encourage clinicians to consider the use of primary thromboprophylaxis in ambulatory cancer patients at intermediate to high risk of VTE who do not have any apparent risk factors for bleeding. The direct oral Xa inhibitors have also been assessed in the acute management of cancer-associated thrombosis. Current evidence suggests that these drugs are a convenient, effective, and safe option for the management of acute VTE in many cancer patients. Low-molecular weight heparin, however, may continue to be the treatment of choice depending on the presence of bleeding risk factors, the type of cancer, drug-drug interactions, and patient preferences.

Direct Oral Factor Xa Inhibitors for the Treatment of Acute Cancer-Associated Venous Thromboembolism: A Systematic Review and Network Meta-analysis

OBJECTIVE

To explore the efficacy and safety of direct oral factor Xa inhibitors in the treatment of cancer-associated acute venous thromboembolism (VTE).

PATIENTS AND METHODS

MEDLINE, CENTRAL (Cochrane Central Register of Controlled Trials), and Embase databases were searched for trials comparing direct oral anticoagulants (DOACs) to dalteparin for the management of cancer-associated acute VTE. Databases were searched from inception to September 19, 2018. A network meta-analysis using both frequentist and Bayesian methods was performed to analyze VTE recurrence and major and clinically relevant nonmajor bleeding.

RESULTS

We identified 3 randomized controlled trials, at low risk of bias, that enrolled 1739 patients with cancer-associated VTE. Direct comparison revealed a lower rate of VTE recurrence in DOAC compared with dalteparin groups (odds ratio [OR], 0.48; 95% CI, 0.24-0.96; I²=46%). Indirect comparison suggested that apixaban had greater reduction in VTE recurrence compared with dalteparin (OR, 0.10; 95% CI, 0.01-0.82) but not rivaroxaban or edoxaban. Apixaban also had the highest probability of being ranked most effective. By direct comparisons, there was an increased likelihood of major bleeding in the DOAC group compared with dalteparin (OR, 1.70; 95% CI, 1.04-2.78). Clinically relevant nonmajor bleeding did not differ. Indirect estimates were imprecise. Subgroup analyses in gastrointestinal cancers suggested that dalteparin may have the lowest risk of bleeding, whereas estimates in urothelial cancer were imprecise.

CONCLUSION

Direct oral anticoagulants appear to lower the risk of VTE recurrence compared with dalteparin while increasing major bleeding. Apixaban may be associated with the lowest risk of VTE recurrence compared with the other DOACs.

Clinical implications of incidental venous thromboembolism in cancer patients

Introduction

In cancer patients, current guidance suggests similar treatment for incidental and symptomatic venous thromboembolism (VTE), mainly based on retrospective data. We aimed to evaluate anticoagulant therapy in cancer patients with incidental and symptomatic VTE.

Methods

The Hokusai VTE Cancer Study was a randomised controlled trial comparing edoxaban with dalteparin for cancer-associated VTE. The primary outcome was the composite of first recurrent VTE or major bleeding. Secondary outcomes included major bleeding, recurrent VTE and mortality. Outcomes in patients with incidental and symptomatic VTE were evaluated during the 12-month study period.

Results

331 patients with incidental VTE and 679 patients with symptomatic VTE were enrolled, of whom the index event was confirmed by an independent radiologist. Median durations of anticoagulant treatment were 195 and 189 days, respectively. In patients with incidental VTE, the primary outcome occurred in 12.7% of patients, major bleeding in 6.6% of patients and recurrent VTE in 7.9% of patients. Out of the 26 VTE recurrences in patients with incidental VTE, five (31%) were incidental, seven (44%) were symptomatic and four (25%) were deaths for which pulmonary embolism could not be ruled out. In patients with symptomatic VTE, the primary outcome occurred in 13.8% of patients, major bleeding in 4.9% of patients and recurrent VTE in 10.9% of patients. All-cause mortality was similar in both groups.

Conclusion

Clinical adverse outcomes are substantial in both cancer patients with incidental and symptomatic VTE, supporting current guideline recommendations that suggest treating incidental VTE in the same manner as symptomatic VTE.

Comparison of apixaban to rivaroxaban and enoxaparin in acute cancer-associated venous thromboembolism

To provide direct comparison between apixaban and rivaroxaban in patients with acute cancer-associated venous thromboembolism (Ca-VTE), consecutive patients treated with apixaban, rivaroxaban, or enoxaparin at Mayo Thrombophilia Clinic (March 1, 2013 to January 31, 2018)) were followed prospectively. The primary effectiveness outcome was venous thromboembolism (VTE) recurrence, and the secondary was mortality. The primary safety outcome was major bleeding, the secondary clinically relevant safety outcome was non-major bleeding (CRNMB), and the third a composite of major and CRNMB. There were 750 patients treated for acute Ca-VTE with apixaban (n = 224), rivaroxaban (n = 163), and enoxaparin (n = 363) within 14 days of diagnosis and for at least 3 months, or until study event. Recurrent VTE was diagnosed in 11 receiving apixaban, 7 receiving rivaroxaban (apixaban vs rivaroxaban hazard ratio (HR) 1.31, 95% confidence interval (95% CI) 0.51-3.36) and 17 in the enoxaparin receiving group (apixaban vs enoxaparin HR 1.14, 95% CI: 0.54, 2.42 and rivaroxaban vs enoxaparin HR 0.85, 95% Cl: 0.36, 2.06). There were 82 deaths in apixaban, 74 rivaroxaban (apixaban vs rivaroxaban HR 1.67, 95% Cl: 1.20, 2.33) and 171 in enoxaparin group (rivaroxaban vs enoxaparin HR 0.73, 95% Cl: 0.56, 0.96). Major bleeding occurred in 11 apixaban, 12 rivaroxaban (apixaban vs rivaroxaban HR 0.73, 95% Cl: 0.32, 1.66) and 21 enoxaparin group (apixaban vs enoxaparin HR 0.89, 95% Cl: 0.43, 1.84 and rivaroxaban vs enoxaparin HR 1.23, 95% Cl: 0.61, 2.50). The CRNMB rate was higher in rivaroxaban compared to apixaban (P = .03) and LMWH (P = .01) groups. Recurrence of VTE and major bleeding were similar in apixaban, rivaroxaban, and enoxaparin groups. Rivaroxaban was associated with higher CRNMB but lower mortality compared to apixaban and enoxaparin.

Venous Thromboembolism: Role of the Clinical Laboratory in Diagnosis and Management

Background

Venous thromboembolism (VTE) is the third most common cause of cardiovascular illness and is projected to double in incidence by 2050. It is a spectrum of disease that includes deep venous thrombosis (DVT) and pulmonary embolism (PE). In February 2016, the American College of Chest Physicians provided updated management guidelines for DVT and PE to address some of the unresolved questions from the previous version and to provide recommendations related to newer anticoagulants.

Content

Here we review current concepts for screening, diagnosis, thromboprophylaxis, and management of DVT and PE. We also describe the management of VTE in acute, long-term, and extended phases of treatment. Thrombophilia testing is rarely necessary and should be used judiciously; the laboratory can serve an important role in preventing unnecessary testing. The direct oral anticoagulants are as effective as conventional treatment and are preferred agents except in the case of cancer. The initial management of PE should be based on risk stratification including the use of D-dimer testing. Thrombolysis is used in cases of hemodynamically unstable PE and not for low-risk patients who can be treated on an outpatient basis.

Summary

This review is intended to provide readers with updated guidelines for screening, testing, prophylaxis, and management from various organizations.

Venous Thromboembolism Incidence and Prophylaxis Use After Gastrectomy Among Korean Patients With Gastric Adenocarcinoma: The PROTECTOR Randomized Clinical Trial

Importance

The guidelines by the National Comprehensive Cancer Network and the American Society for Clinical Oncology recommend the routine use of thromboprophylaxis for patients with gastric adenocarcinoma. However, many physicians in Asian countries use venous thromboembolism (VTE) prophylaxis much less often because of the perceived lower VTE incidence in this population.

Objectives

To evaluate the incidence of postgastrectomy VTE in Korean patients with gastric adenocarcinoma, and to identify the complications and evaluate the efficacy and safety of VTE prevention methods.

Design, Setting, and Participants

The Optimal Prophylactic Method for Venous Thromboembolism After Gastrectomy in Korean Patients (PROTECTOR) randomized clinical trial was conducted between August 1, 2011, and March 31, 2015. Patients with histologically confirmed gastric adenocarcinoma presenting to a single center (Seoul St Mary's Hospital in Seoul, South Korea) were enrolled. Patients were randomized to either an intermittent pneumatic compression (IPC)-only group or an IPC+low-molecular-weight (LMW) heparin sodium group. The data were analyzed on intention-to-treat and per protocol bases. Data analysis was performed from April 1, 2016, to October 30, 2017.

Main Outcomes and Measures

Venous thromboembolism incidence was the primary outcome. Postoperative complications, particularly those associated with VTE prophylaxis methods, were the secondary end point.

Results

Of the 682 patients enrolled and randomized, 447 (65.5%) were male and 245 (34.5%) were female, with a mean (SD) age of 57.67 (12.94) years. Among the 666 patients included in the analysis, the overall incidence of VTE was 2.1%. The incidence of VTE was statistically significantly higher in the IPC-only group compared with the IPC+LMW heparin group (3.6%; 95% CI, 2.05%-6.14% vs 0.6%; 95% CI, 0.17%-2.18%; P = .008). Among the 14 patients (2.1%) with VTE, 13 were asymptomatic and received a deep vein thrombosis diagnosis, whereas 1 patient received a symptomatic pulmonary thromboembolism diagnosis. The overall incidence of bleeding complications was 5.1%. The incidence of bleeding complications was significantly higher in the IPC+LMW heparin group compared with the IPC-only group (9.1% vs 1.2%; P < .001). No cases of VTE-associated mortality were noted.

Conclusions and Relevance

Use of IPC alone is inferior to the use of IPC+LMW heparin in preventing postoperative VTE. Because LMW heparin is associated with a high bleeding risk, further study is needed to stratify the patients at high risk for perioperative development of VTE.

Trial Registration

ClinicalTrials.gov Identifier: NCT01448746.

Long-term rivaroxaban for the treatment of acute venous thromboembolism in patients with active cancer in a prospective multicenter trial

BACKGROUND/AIMS

Limited data are available regarding the efficacy of rivaroxaban for the treatment of cancer-associated venous thromboembolism (VTE). The aim of this study was to evaluate the effectiveness and safety of rivaroxaban for the treatment of VTE in active cancer patients.

METHODS

In this prospective, multicenter, open-label trial (NCT01989845), we enrolled patients with active cancer and objectively diagnosed lower-extremity deep vein thrombosis, pulmonary embolism (PE), or both from November 2013 to June 2016. Active cancer was defined as a histologically confirmed malignancy, which was diagnosed or treated within the previous 6 months, or as a recurrent/ metastatic cancer. Patients received oral rivaroxaban 15 mg twice daily for first 3 weeks, followed by 20 mg once daily for 6 months. The primary outcome was the symptomatic recurrent VTE and the secondary outcomes included any recurrent VTE, major or clinically relevant non-major (CRNM) bleeding events, and overall mortality. All study outcomes were validated by blinded central adjudication.

RESULTS

Of 124 patients enrolled, 110 (88.7%) had solid cancer, 93 (75.0%) had metastatic disease, and 110 (88.7%) were receiving chemotherapy or radiotherapy. During the 6-month study period, seven patients experienced symptomatic recurrent VTE (cumulative incidence, 5.9%), and two patients experienced incidental recurrent PE (cumulative incidence of any recurrent VTE, 7.6%). Major bleeding events occurred in six patients (cumulative incidence, 5.3%) and CRNM bleeding events in 11 patients (cumulative incidence, 10.2%). Twenty-eight patients (overall mortality, 24.0%) died.

CONCLUSION

Rivaroxaban is effective and safe for the treatment of VTE in patients with active cancer.

Incidence of cancer-associated thromboembolism in Japanese gastric and colorectal cancer patients receiving chemotherapy: a single-institutional retrospective cohort analysis (Sapporo CAT study)

OBJECTIVE

Few data regarding the incidence of cancer-associated thromboembolism (TE) are available for Asian populations. We investigated the incidence of TE (TEi) and its risk factors among gastric and colorectal cancer (GCC) patients received chemotherapy in a daily practice setting.

DESIGN

A retrospective cohort study.

SETTING

A single-institutional study that used data from Sapporo City General Hospital, Japan, on patients treated between January 2008 and May 2015.

PARTICIPANTS

Five hundred Japanese GCC patients who started chemotherapy from January 2008 to May 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

TE was diagnosed by reviewing all the reports of contrast-enhanced CT performed during the follow-up period. All types of thrombosis detected by CT or additional imaging tests, such as venous TE, arterial TE and cerebral infarction, were defined as TE. Medical records of all identified patients were reviewed and potential risk factors for TE, including clinicopathological backgrounds, were collected. We defined the following patients as 'active cancer'; patients with unresectable advanced GCC, cancer recurrence during or after completing adjuvant chemotherapy and/or presence of other malignant tumours.

RESULTS

Of the 500 patients, 70 patients (14.0%) developed TE during the follow-up period. TEi was 9.2% and 17.3% in GCC patients, 18.1% and 3.5% in active and non-active cancer patients, and 24.0% and 12.9% in multiple and single primary, respectively. Multivariate logistic regression analysis showed that colorectal cancer (CRC) (OR 2.371; 95% CI 1.328 to 4.233), active cancer (OR 7.593; 95% CI 2.950 to 19.543) and multiple primary (OR 2.527; 95% CI 1.189 to 5.370) were independently associated with TEi.

CONCLUSION

TEi was 14.0% among Japanese GCC patients received chemotherapy, and was significantly higher among patients with CRC, active cancer and multiple primary than among those with gastric cancer, non-active cancer and single primary, respectively.

TRIAL REGISTRATION NUMBER

UMIN000018912.

Indian Brachytherapy Society Guidelines for radiotherapeutic management of cervical cancer with special emphasis on high-dose-rate brachytherapy

Brachytherapy (BT) for locally advanced cervical cancer is vital for optimal outcomes. There is heterogeneity in brachytherapy treatment practice for cervical cancer across India. In an attempt to standardize various processes involved in cervical cancer brachytherapy, the expert members of the Indian Brachytherapy Society (IBS) developed a document related to radiation therapy treatment of cervical cancer with special emphasis on brachytherapy. The guidelines are based on high quality clinical evidence, expert opinion and consensus wherever evidence was lacking. The document provides a guide for external beam radiation and details of all the processes involved in high-dose-rate (HDR) brachytherapy including patient selection, preparation, principles and technique of BT applications, target and normal tissue definition, dose prescriptions, BT planning, reporting parameters, common complications of BT and their management, scope for research, etc. In summary, we present here practical tips and tricks, recording and reporting of cervical cancer brachytherapy, which can be implemented in various clinical environments and forms the basis of this report.

The Ottawa score performs poorly in cancer patients with incidental pulmonary embolism

BACKGROUND

The Ottawa score was previously developed to predict recurrent venous thromboembolism (VTE) in cancer patients with VTE. The performance of this score in patients with incidental VTE is currently unclear.

AIM

To evaluate the performance of the Ottawa risk score in cancer patients with incidental pulmonary embolism included in an international, prospective, observational cohort study.

METHODS

The score was used to classify patients as high (≥1), intermediate (0), or low risk (≤-1). The discriminative performance of the score was estimated by calculating the cumulative incidence of recurrent VTE for all groups, the time-dependent c-statistic, and the sub-distribution hazard ratio (SHR), using a competing risk approach.

RESULTS

Of the 691 patients for which the Ottawa score could be calculated, 25 (3.6%) had recurrent VTE during 6-month follow-up and 38 (5.5%) during 12-month follow-up. The c-statistics of the continuous score at 6 and 12 months were 0.45 (95% CI, 0.36-0.54) and 0.51 (95% CI, 0.46-0.59), respectively. The 6-month cumulative incidences of recurrent VTE for those at low, intermediate, and high risk were 3.9% (95% CI, 1.5-8.4), 3.6% (95% CI, 1.9-6.2), and 3.6% (95% CI, 1.8-6.5), respectively. A sensitivity analysis restricted to the on-treatment period yielded similar results. None of the Ottawa risk score items were significantly associated with recurrent VTE.

CONCLUSION

In cancer patients with incidental pulmonary embolism, the Ottawa risk score has a poor predictive value for recurrent VTE, which does not support the use of the score in this patient population.

Evaluation of direct oral anticoagulants for the treatment of cancer-associated thrombosis: an update

Cancer is associated with an increased risk of venous thromboembolism of four to sixfold. Cancer-related interventions such as chemotherapy, hormonal therapy and indwelling central venous catheters also increase the risk of venous thromboembolism. Low molecular weight heparin for at least 3-6 months is the current standard of care for the treatment of cancer associated venous thromboembolism. Anticoagulation should be continued as long as the cancer is active. Over the past few years, direct oral anticoagulants have emerged, including one direct thrombin inhibitor (dabigatran etexilate) and three factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). In the randomized controlled trials comparing direct oral anticoagulants with vitamin K antagonists, the direct oral anticoagulants all provide non-inferior in prevention of thromboembolic events in patients with atrial fibrillation, for the prevention and treatment of venous thromboembolism and in acute coronary syndrome. In people with cancer, these drugs have emerged as attractive alternatives for the treatment of venous thromboembolism with the potential to overcome the limitations of low molecular weight heparin. Randomized controlled studies comparing direct oral anticoagulants to low molecular weight heparin in cancer patients are still limited and direct oral anticoagulants are not recommended for the treatment of cancer associated venous thromboembolism yet. However, new emerging data are supporting the use of direct oral anticoagulants in cancer-associated thrombosis. Here, we review recent data on the evidence related to the efficacy and safety of direct oral anticoagulants for the treatment of venous thromboembolism in patients with cancer.

Efficacy and Safety of Direct Oral Anticoagulants for Secondary Prevention of Cancer-Associated Thrombosis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Prospective Cohort Studies

Background: Venous thromboembolism (VTE) is a common complication in patients with cancer. Direct oral anticoagulants (DOACs) have been proved to be effective on anticoagulation therapy in many diseases. However, the efficacy and the safety of DOACs in the secondary prevention of cancer-associated thrombosis (CAT) remain unclear. To assess the value of DOACs in patients with CAT, we performed a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies. Methods: Medline, Embase, and the Cochrane Library were searched from their earliest date through to June 2018. Two investigators independently assessed eligibility. Data were extracted by one investigator and verified by the second investigator. The efficacy outcome of this study was recurrent VTE, whereas the safety outcome was major and clinically relevant nonmajor bleeding. Relative risks (RRs) and their corresponding 95% confidence interval (CI) were determined. To pool the results, the Mantel-Haenszel fixed-effects or random-effects models were used. Results: A total of nine articles (six randomized controlled trials and three prospective studies) involving 2,697 patients with CAT who were prescribed DOACs (apixaban, edoxaban, rivaroxaban, or dabigatran) and 2,852 patients who were prescribed traditional anticoagulants [vitamin K antagonists (VKAs), low molecular weight heparin (LMWH), dalteparin, or enoxaparin] were compared. VTE recurrence in the DOAC group was significantly lower than that observed in the traditional anticoagulant group (RR: 0.60; 95%CI: 0.49-0.75; I 2: 0%; p < 0.00001). No significant difference in bleeding risk between both groups was found (RR: 0.95; 95%CI: 0.67-1.36; I 2: 75%; p = 0.79). Conclusions: Our findings showed that anticoagulant therapy with DOACs may be more effective than traditional anticoagulants to prevent recurrent VTE in patients with CAT, while the safety of DOACs may be equal to that of traditional anticoagulants. These findings support the use of DOACs as the first-line therapy for secondary prevention of CAT in most cancer patients.

Extended treatment of cancer-associated thrombosis

Venous thromboembolism (VTE) is a growing concern in patients with cancer. Current guidelines recommend that cancer patients with VTE should receive anticoagulation for at least 3-6 months. However, the question as to whether anticoagulants should be continued after 3 to 6 months of treatment remains open. In presence of an active malignancy, physicians should weigh the benefits and burdens of ongoing anticoagulation taking into account the clinical status, patient expectations, and the risk of bleeding. As the length of time from the index event increases, the available evidence is not conclusive. The most critical unresolved issues include the decision to continue or discontinue anticoagulation and the selection of the most appropriate anticoagulant agent. On this background, our article provides an overview of the available studies focusing on extended (i.e., >6 months) anticoagulation treatment in cancer-associated thrombosis, with the ultimate goal of refining real-world clinical decision-making in this patient population.

Treatment of Cancer-Associated Thrombosis: Beyond HOKUSAI

Direct oral anticoagulants (DOACs) represent an attractive alternative to low-molecular-weight heparins (LMWHs) for the long-term treatment of cancer-associated thrombosis (CT) since they avoid the burden of daily injections. Analyses in subgroups of cancer patients from large randomized trials suggested that DOACs were at least as effective as vitamin K antagonists, while indirect comparisons suggested that DOACs' efficacy and safety profile were comparable to those of LMWHs. In the randomized controlled HOKUSAI-VTE Cancer study, currently the only completed phase III trial on DOACs in CT patients, edoxaban was shown noninferior to dalteparin on the composite primary endpoint of time to first recurrent venous thromboembolism or major bleeding during the 12 months after randomization. Study results suggest that both agents had comparable benefit/risk ratio in patients with CT. Even though this conclusion was valid from a strict statistical viewpoint, it was potentially misleading when interpreting benefit/risk ratios. Besides the obvious heterogeneity of the study population (e.g., 23% of patients no longer had cancer) and significantly different treatment durations between arms, secondary outcomes for efficacy were in favor of edoxaban for recurrent deep-vein thrombosis but not for recurrent pulmonary embolism, and major bleeding episodes were significantly more frequent in the edoxaban group, with an excess of gastrointestinal (GI) bleeding episodes observed mainly but not only in patients with GI cancers. More research is needed regarding specific patients' profiles, cancer types, and treatment period to better clarify the respective roles of DOACs and LMWHs in CT patients.

Recent advances in the treatment and prevention of venous thromboembolism in cancer patients: role of the direct oral anticoagulants and their unique challenges

Venous thromboembolism (VTE) is a common complication in patients with cancer and is associated with poor prognosis. Low-molecular-weight heparins (LMWHs) are the standard of care for the treatment of cancer-associated thrombosis. Primary VTE prophylaxis with LMWH is recommended after cancer surgery and in hospitalized patients with reduced mobility. However, owing to wide variations in VTE and bleeding risk, based on disease stage, anti-cancer treatments, and individual patient characteristics, routine primary prophylaxis is not recommended in ambulatory cancer patients undergoing chemotherapy. Efforts are under way to validate risk assessment models that will help identify those patients in whom the benefits of primary prophylaxis will outweigh the risks. In recent months, long-awaited dedicated clinical trials assessing the direct oral anticoagulants (DOACs) in patients with cancer have reported promising results. In comparison with the LMWHs, the DOACs were reported to be non-inferior to prevent VTE recurrence. However, there was an increased risk of bleeding, particularly in gastrointestinal cancers. Safe and optimal treatment with the DOACs in the patient with cancer will require vigilant patient selection based on patient characteristics, co-morbidities, and the potential for drug-drug interactions.

Postoperative venous thromboembolism and mortality in patients with pancreatic surgery

BACKGROUND AND OBJECTIVES

Pancreatic cancer is strongly associated with thrombosis. We investigated early postoperative venous thromboembolism (PVTE) mortality among patients with pancreatic surgery and compared outcomes in adenocarcinoma pancreatic cancer (ACPC) to non-adenocarcinoma pancreatic neoplasm (NACPN).

METHODS

We analyzed a prospectively collected database of patients who underwent pancreatic cancer or neoplasm-related surgery. As NACPN is underrepresented in other studies, we selected NACPN patients and a random sample of ACPC patients. PVTE was defined as VTE occurring within 3 months of surgical intervention. Statistical analysis was performed using Cox proportional hazards regression.

RESULTS

A total of 441 pancreatic surgery patients were included, with 331 ACPC and 110 NACPN. Median follow-up was 449 days during which 90 (20.4%) patients developed VTE. PVTE occurred in 53 (12.0%) patients, including 41 (12.4%) ACPC patients and 12 (10.9%) NACPN patients. Those with PVTE had 60% higher mortality rate. A multivariable analysis found that PVTE is an independent predictor of increased mortality (HR Adj, 1.6; 95% CI, 1.1-2.2; P < .01). The mortality impact was not consistent between ACPC (HR, 3.2; 95% CI, 1.3-7.9) and NACPN groups (HR, 1.3; 95% CI, 0.9-1.8).

CONCLUSIONS

Postoperative venous thromboembolism is an independent predictor of increased mortality in pancreatic surgery, specifically in adenocarcinoma pancreatic cancer surgery.

Direct oral anticoagulants for treatment and prevention of venous thromboembolism in cancer patients

Venous thromboembolism (VTE) is a common cause of morbidity and mortality in patients with cancer. Compared with the general population, cancer patients with VTE have higher rates of both VTE recurrence and bleeding. While low molecular weight heparin (LMWH) has been the mainstay of treatment for cancer-associated VTE for over a decade, direct oral anticoagulants (DOACs) have recently emerged as a new therapeutic option due to their ease of administration and because they do not require laboratory monitoring. Several large randomized clinical trials have been performed or are ongoing at the time of writing, comparing DOACs with LMWH in this population. Three of these trials have thus far been published and suggest that DOACs are a reasonable alternative to LMWH for management of cancer-associated VTE. Despite the advantages offered by DOACs, these agents may not be appropriate for certain patient groups owing to increased risk of bleeding, organ compromise, extremes of weight, and other issues. Finally, data are emerging suggesting that DOACs may be useful for primary thromboprophylaxis in cancer patients in conjunction with validated risk assessment scores. In this evidence-based review, data for the use of DOACs to treat cancer-associated VTE will be examined, focusing on efficacy, safety, and timing of treatment. Guidance on choosing the optimal anticoagulant for a given patient is also offered.

Thrombosis Risk Associated with Head and Neck Cancer: A Review

Venous thromboembolism (VTE) is a common complication for cancer patients. VTE-associated risk varies according to the type of tumor disease. Head and neck cancer is a common cancer worldwide, and most tumors are squamous cell carcinomas due to tobacco and alcohol abuse. The risk of VTE associated with head and neck (H&N) cancer is considered empirically low, but despite the high incidence of H&N cancer, few data are available on this cancer; thus, it is difficult to state the risk of VTE. Our review aims to clarify this situation and tries to assess the real VTE risk associated with H&N cancer. We report that most clinical studies have concluded that there is a very low thrombosis risk associated with H&N cancer. Even with the biases that often exist, this clinical review seems to confirm that the risk of VTE was empirically hypothesized. Furthermore, we highlight that H&N cancer has all the biological features of a cancer associated with a high thrombosis risk, including a strong expression of procoagulant proteins, modified thrombosis/fibrinolysis mechanisms, and secretions of procoagulant microparticles and procoagulant cytokines. Thus, this is a paradoxical situation, and some undiscovered mechanisms that could explain this clinical biological ambivalence might exist.

Neutrophil extracellular traps induced by activated platelets contribute to procoagulant activity in patients with colorectal cancer

Patients with colorectal cancer (CRC) are at increased risk of venous thrombosis, but the precise mechanisms of thrombogenesis in CRC remain largely unknown. We aimed to identify the novel role of neutrophil extracellular traps (NETs) in the induction of procoagulant activity (PCA) in CRC, and to evaluate its interactions with platelets and endothelial cells (ECs). In this study, we first showed that the levels of NETs in the peripheral blood of CRC patients were increased in parallel with cancer progression and reached significance in stage II patients compared to healthy subjects. In addition, neutrophils from CRC patients were more prone to produce NETs, resulting in shortened coagulation time, significantly increased thrombin-antithrombin (TAT) complexes and fibrin fibrils compared to healthy controls. Furthermore, platelets from CRC patients stimulated healthy neutrophils to extrude NETs, which could be inhibited by the depletion of HMGB1. Conversely, NETs from CRC patients could also induce the exposure of PS on platelets, leading to markedly enhanced PCA. Importantly, ECs were also converted to a procoagulant phenotype when exposed to NETs from CRC patients. The PCA of NETs-activated platelets or ECs could be inhibited either by the cleavage of NETs with DNase1 or the blockage of histone with activated protein C (APC). Our results reveal the complex interactions between neutrophils, platelets and ECs and their potential role in the hypercoagulable state in CRC. We propose that NETs may provide new therapeutic targets to combat the thrombotic consequences of CRC.

Updated meta-analysis on prevention of venous thromboembolism in ambulatory cancer patients

Randomized clinical trials have evaluated the role of anticoagulants in the prevention of venous thromboembolism (VTE) in ambulatory cancer patients treated with chemotherapy. This meta-analysis is aimed at providing an updated evaluation of the efficacy and safety of anticoagulant prophylaxis in this clinical setting. Medline and Scopus were searched to retrieve randomized controlled trials on the prevention of VTE in ambulatory cancer patients. Two groups of trials were identified with VTE or death as the primary outcome, respectively. VTE was the primary outcome of this analysis. Anticoagulant prophylaxis reduced the incidence of VTE in studies in which the primary outcome was VTE [14 studies, 8,226 patients; odds ratio (OR)=0.45; 95% confidence interval (95% CI): 0.36-0.56] or death (8 studies, 3,727 patients; OR=0.61; 95% CI: 0.47-0.81). When these studies were pooled together, VTE was reduced by 49% (95% CI: 0.43-0.61) with no significant increase in major bleeding (OR=1.30, 95% CI: 0.98-1.73). The risk of major bleeding was increased in studies with VTE as the primary outcome (OR=1.43, 95% CI: 1.01-2.04). Similar reductions of VTE were observed in studies with parenteral (OR=0.43, 95% CI: 0.33-0.56) or oral anticoagulants (OR=0.49, 95% CI: 0.33-0.74). The reduction in VTE was confirmed in patients with lung (OR=0.42, 95% CI: 0.26-0.67) or pancreatic cancer (OR=0.26, 95% CI: 0.14-0.48), in estimated high-risk patients, in high-quality studies and with respect to symptomatic VTE. In conclusion, prophylaxis with oral or parenteral anticoagulants reduces the risk of VTE in ambulatory cancer patients, with an acceptable increase in major bleeding.

The incidence and risk factors of thrombosis and the need for thromboprophylaxis in lymphoma and leukemia patients: A 9-year single-center experience

Background

Patients with cancer are at increased risk of thromboembolic complications. There is no evidence-based guideline on the use of routine prophylaxis in hematological malignancies except in patients with multiple myeloma. The purpose of this study was to determine the incidence and risk factors of thrombosis and suggest a rationale for primary thromboprophylaxis in acute leukemia and lymphoma patients.

Patients and methods

A retrospective study was conducted on newly-diagnosed acute leukemia and lymphoma patients who presented at our institution from November 2009 to March 2018. The study included a total of 157 patients with acute leukemia and 238 patients with lymphoma. The groups were analyzed to determine the incidence and risk factors of thromboembolic complications.

Results

The incidence of all thrombotic complications was 10.12% (40/395) including 11.4% (18/157) in patients with acute leukemia and 9.2% (22/238) in patients with lymphoma. The majority of events occurred in the first 6 months. Acute leukemia patients with thrombosis had a higher number of comorbidities than those without thrombosis ( p < 0.05). Lymphoma patients with thrombotic complications had significantly higher beta-2-microglobulin and lactate dehydrogenase levels compared to those without thrombosis ( p < 0.05). Major bleeding events developed in five (3.1%) acute leukemia patients and two (0.8%) lymphoma patients. All the major bleeding events occurred when the patients were thrombocytopenic (platelet < 50,000/mm3).

Conclusions

Acute leukemia patients with any comorbidity and lymphoma patients with higher lactate dehydrogenase and beta-2-microglobulin are at high risk of developing thromboembolic complications. The prophylactic use of anticoagulant should be considered for those patients especially in the first 6 months.