Risk assessment of recurrence of venous thromboembolism

Recurrent venous thromboembolism is associated with increased mortality in 5-9% of the patients. On the other hand prolonged anticoagulation can increase the bleeding risk which can also be responsible for an increased mortality. Therefore, it is necessary to validate the recurrence risk of venous thromboembolism on an individual basis. In this review the most relevant risk factors for recurrent venous thromboembolism are analyzed. Spontaneous thrombosis is associated with significantly increased recurrence rates in comparison to risk associated venous thrombosis. In addition, a positive D-dimer result after stop of anticoagulation, an increased amount of residual thrombus in proximal veins analyzed by compression sonography, a proximal localization of thrombosis, symptomatic pulmonary embolism and male sex are clinically relevant risk factors for increased recurrence rates. While mild thrombophilic defects like heterozygous factor V Leiden mutation are not associated with a clinically relevant recurrence risk, inherited inhibitor deficiencies and the antiphospholipid-syndrome are known to be responsible for an increased recurrence rate of venous thromboembolism. A new recurrence risk-score (RR-Score) for individual judgement of patients with a first spontaneous venous thrombosis is introduced.     

DVT and pulmonary embolism: Part II. Treatment and prevention

Treatment goals for deep venous thrombosis include stopping clot propagation and preventing the recurrence of thrombus, the occurrence of pulmonary embolism, and the development of pulmonary hypertension, which can be a complication of multiple recurrent pulmonary emboli. About 30 percent of patients with deep venous thrombosis or pulmonary embolism have a thrombophilia. An extensive evaluation is suggested in patients younger than 50 years with an idiopathic episode of deep venous thrombosis, patients with recurrent thrombosis, and patients with a family history of thromboembolism. Infusion of unfractionated heparin followed by oral administration of warfarin remains the mainstay of treatment for deep venous thrombosis. Subcutaneously administered low-molecular-weight (LMW) heparin is at least as effective as unfractionated heparin given in a continuous infusion. LMW heparin is the agent of choice for treating deep venous thrombosis in pregnant women and patients with cancer. Based on validated protocols, warfarin can be started at a dosage of 5 or 10 mg per day. The intensity and duration of warfarin therapy depends on the individual patient, but treatment of at least three months usually is required. Some patients with thrombophilias require lifetime anticoagulation. Treatment for pulmonary embolism is similar to that for deep venous thrombosis. Because of the risk of hypoxemia and hemodynamic instability, in-hospital management is advised. Unfractionated heparin commonly is used, although LMW heparin is safe and effective. Thrombolysis is used in patients with massive pulmonary embolism. Subcutaneous heparin, LMW heparin, and warfarin have been approved for use in surgical prophylaxis. Elastic compression stockings are useful in patients at lowest risk for thromboembolism. Intermittent pneumatic leg compression is a useful adjunct to anticoagulation and an alternative when anticoagulation is contraindicated.     

Comparison of 1 month with 3 months of anticoagulation for a first episode of venous thromboembolism associated with a transient risk factor.

BACKGROUND: The risk of recurrence is lower after treatment of an episode of venous thromboembolism associated with a transient risk factor, such as recent surgery, than after an episode associated with a permanent, or no, risk factor. Retrospective analyses suggest that 1 month of anticoagulation is adequate for patients whose venous thromboembolic event was provoked by a transient risk factor. METHODS: In this double-blind study, patients who had completed 1 month of anticoagulant therapy for a first episode of venous thromboembolism provoked by a transient risk factor were randomly assigned to continue warfarin or to placebo for an additional 2 months. Our goal was to determine if the duration of treatment could be reduced without increasing the rate of recurrent venous thromboembolism during 11 months of follow-up. RESULTS: Of 84 patients assigned to placebo, five (6.0%) had recurrent venous thromboembolism, compared with three of 81 (3.7%) assigned to warfarin, resulting in an absolute risk difference of 2.3%[95% confidence interval (CI) - 5.2, 10.0]. The incidence of recurrent venous thromboembolism after discontinuation of warfarin was 6.8% per patient-year in those who received warfarin for 1 month and 3.2% per patient-year in those who received warfarin for 3 months (rate difference of 3.6% per patient-year; 95% CI - 3.8, 11.0). There were no major bleeds in either group. CONCLUSION: Duration of anticoagulant therapy for venous thromboembolism provoked by a transient risk factor should not be reduced from 3 months to 1 month as this is likely to increase recurrent venous thromboembolism without achieving a clinically important decrease in bleeding.     

Thrombin generation and venous thromboembolism

Venous thromboembolism is a chronic and potential fatal disease. Determination of recurrence risk is time-consuming and costly, and sometimes not feasible: many patients carry more than one risk factor, the relevance of some factors with regard to risk of recurrence is unknown, and existence of thus far unknown risk factors must be considered. A laboratory assay that measures multifactorial thrombophilia would be useful to identify patients at risk of thrombosis. The process of thrombin generation is the central event of the hemostatic process. Thrombin generation is increased in patients at risk of thrombosis including those with antithrombin deficiency or those who are taking hormonal contraceptives. Risk of first and recurrent venous thrombosis is higher in patients with increased thrombin generation. Thus, by use of a simple global marker of coagulation stratification of patients according to their risk of thrombosis is possible. Future studies are needed to improve the management of patients with VTE and increased thrombin generation.     

Individualized duration of oral anticoagulant therapy for deep vein thrombosis based on a decision model

Summary.  Background : The optimal duration of oral anticoagulant therapy for patients with a first episode of deep vein thrombosis (DVT) is still a matter of debate. However, according to the ACCP consensus strategy a limited stratification in treatment duration is advocated, i.e. 3 months for patients with a transient risk factor and 1 year or longer for patients with recurrent disease or a consistent risk factor such as thrombophilia or cancer. This consensus strategy is founded on the mean optimal duration of therapy obtained in large cohorts of patients and is mainly based on the risk of recurrent venous thromboembolism (VTE), with only minimal consideration for the patient's bleeding risk. Objective : The aim of this study is to optimize the anticoagulant treatment strategy with vitamin K antagonists for the individual patient with DVT. Methods : Based on an extensive literature study, a mathematical model was constructed to balance the risk of recurrent VTE against the risk of major hemorrhagic complications. The following parameters are incorporated in the model: baseline estimates and risk factors for recurrent VTE and bleeding, clinical course of DVT, and efficacy of treatment with vitamin K antagonists. With the use of these parameters, the risk for a recurrent VTE and a bleeding episode can be calculated for the individual patient. The optimal duration of anticoagulant therapy can be defined as the timepoint at which the benefit of treatment (prevention of VTE) is counterbalanced by its risk (bleeding). Results/conclusions : How long a patient should receive anticoagulant treatment is a matter of balancing the benefits and risks of treatment. The model shows that the optimal treatment duration varies greatly from patient to patient according to the patient's unique bleeding and recurrence risk.     

下肢深静脉血栓非手术疗法治疗后复发的影响因素

目的探讨非手术疗法治疗下肢深静脉血栓复发的影响因素,以提出改善预后的干预措施。方法采用病例对照研究的方法,将2004年2月至2008年4月行血管外科非手术治疗的下肢深静脉血栓患者167例按出院后18个月内是否复发分为复发与未复发两组,在收集病历资料和进行电话随访的基础上,通过单因素分析和非条件Logistic逐步回归分析复发的影响因素。结果非条件Logistic逐步回归分析表明,高龄、有骨科疾病及手术史、妊娠、不穿弹力袜或不使用绷带、未按时口服抗凝药物是非手术疗法治疗下肢深静脉血栓复发的危险因素,OR值分别为3.616、1.560、9.296、1.973、7.959。结论作为预防下肢深静脉血栓复发的保护因素,应嘱患者按时口服抗凝药物、下床时穿弹力袜或使用绷带;而对于高龄、有骨科疾病及手术史、妊娠者更要加强护理干预,积极预防下肢深静脉血栓形成的复发。     

A conceptual framework for two phases of anticoagulant treatment of venous thromboembolism

Summary. Four observations support that anticoagulant therapy for venous thromboembolism (VTE) has an ‘active treatment’ phase that is limited to about 3 months. First, <3 months of treatment is associated with a higher risk of recurrent VTE than treatment for 3 months or longer, suggesting that <3 months is inadequate therapy. Second, treatment for 3 months is associated with the same risk of recurrent VTE as treatment for 6 months or longer, suggesting that 3 months is adequate therapy. Third, the increase in recurrent VTE with too short a course of treatment is predominantly at the site of the initial thrombosis, suggesting reactivation of initial thrombosis. Fourth, the increase in recurrent VTE with too short a course of treatment occurs immediately after treatment is stopped and is short lived, again suggesting reactivation of initial thrombosis. Once the initial thrombosis has been adequately treated (i.e. the first phase of treatment), further anticoagulation serves as ‘secondary prevention’ of new, unrelated, episodes of thrombosis (i.e. the second phase of treatment). For most patients, therefore, anticoagulant therapy for VTE should be stopped at 3 months when the acute episode has completed treatment, or should be continued indefinitely as ‘secondary prevention’ if the risk of recurrence remains unacceptably high having completed ‘active treatment’.     

The risk of recurrent venous thromboembolism: the Austrian Study on Recurrent Venous Thromboembolism

Venous thromboembolism (VTE) is a chronic disease. After withdrawal of oral anticoagulation at least a third of patients will experience a subsequent episode of venous thrombosis. Of these patients, approximately 5% will die from pulmonary embolism. The Austrian Study on Recurrent Venous Thromboembolism (AUREC) is a prospective cohort study aiming to investigate the overall rate of recurrent VTE, the predictive value of laboratory assays, the importance of acquired or congenital risk factors for thrombosis and the impact of extended or modified secondary thromboprophylaxis on the risk of recurrence among high-risk patients. So far, the AUREC investigators have identified subgroups of patients with a particular high risk of recurrence: patients with a history of venous thrombosis, elevated levels of coagulation factors VIII, IX and XI, pulmonary embolism or superficial venous thrombosis and a history of venous thrombosis and hyperhomocysteinemia. Patients with a history of venous thrombosis and mutations in genes encoding for coagulation factors (factor V Leiden, factor II, G20210A) do not have an enhanced risk of recurrence and, thus, do not qualify for extended secondary thromboprophylaxis. At present, interventional trials are in progress in patients with high factor VIII or hyperhomocysteinemia in order to investigate if these patient groups might benefit from extended oral anticoagulation or vitamin supplementation, respectively.     

The risk of recurrent venous thromboembolism among patients with high factor IX levels

Summary.  High factor IX (FIX) is a risk factor of deep vein thrombosis. The impact of high FIX on the risk of recurrent venous thrombosis is unknown. We prospectively followed 546 patients after anticoagulation for a first spontaneous venous thromboembolism. Patients with a natural coagulation inhibitor deficiency, lupus anticoagulant or cancer were excluded. At 3 years, the likelihood of recurrence was 23% among patients with high FIX (exceeding the 75th percentile) compared with 11% among patients with lower levels. Among patients with high FIX, the relative risk of recurrence was 2.2 (95% CI: 1.3–3.6) before and was 1.6 (95% CI: 1.0–2.8) after adjustment for age, gender, duration of anticoagulation, FV Leiden, FII G20210A, high FVIII and hyperhomocysteinemia. Compared with patients with low factor IX (< 138 IU dL⁻¹) and low FVIII (≤ 234 IU dL⁻¹), the relative risk of recurrence was 1.5 among patients with high FIX and low FVIII, 2.7 among patients with low FIX and high FVIII and 6.6 among patients with high FIX and high FVIII. High levels of FIX confer an increased risk of recurrent venous thromboembolism and enhance the risk of recurrence among patients with high FVIII.     

Economy class syndrome

Economy class syndrome is venous thromboembolism following air travel. This syndrome was firstly reported in 1946, and many cases have been reported since 1990s. Low air pressure and low humidity in the aircraft cabin may contribute to the mechanism of this syndrome. Risk factors for venous thrombosis in the plane were old age, small height, obesity, hormonal therapy, malignancy, smoking, pregnancy or recent parturition, recent trauma or operation, chronic disease and history of venous thrombosis. In Japan, the feminine gender is also risk factor though reason was not well known. For prophylaxis, adequate fluid intake and leg exercise are recommended to all passengers. For passengers with high risk, prophylactic measures such as compression stockings, aspirin or low molecular weight heparin should be considered.     

Differential risks in men and women for first and recurrent venous thrombosis: the role of genes and environment

Men have a higher risk of first and recurrent venous thrombosis than do women. However, the pathophysiology underlying this phenomenon is as yet unknown. In this review article, we assessed the prevalence and strength of genetic and acquired risk factors for venous thrombosis for men and women separately, because it is likely that either a difference in effect or distribution of a risk factor explains the risk difference between the sexes. We also summarized the sex‐specific results of previous studies on the risk of first and recurrent venous thrombosis. Few explanations for the sex difference were found. The major factor, explaining about 20% difference in population‐attributable fraction, was body height. No difference in prevalence or strength for other venous thrombosis risk factors was observed, such as plaster cast immobilization, hospitalization, surgery, trauma, malignancy, hyperhomocysteinemia, factor V Leiden, prothrombin G20210A, or blood group non‐O. Alternative explanations for the sex difference are hypothesized in this review, including X‐ or Y‐linked mutations or a mutation on a gene with a sex‐specific effect. Future studies should focus on the sex‐specific risk of venous thrombosis to unravel the pathophysiology and thereby improve sex‐specific treatment and prevention strategies. Even so, male sex can be used as a tool through which individuals at increased risk of first or recurrent venous thrombosis may be identified.     

Factor V Leiden as a Common Genetic Risk Factor for Venous Thromboembolism

PURPOSE: To increase nurses' knowledge of the Factor V Leiden (FVL) genetic trait for venous thromboembolism. Organizing Framework: An overview of the history, prevalence, and predisposition of the FVL genetic mutation, including who should be tested and how and in what circumstances people with FVL should be treated. FINDINGS: FVL is the most commonly recognized genetic trait associated with venous thrombosis. It is found predominantly in Caucasian populations. Biochemically it causes "activated protein C resistance (APCR)." The decision to test for FVL depends on whether the information gained will potentially improve the health care of the person or family. For people who have had deep venous thrombosis, testing for FVL will likely not alter treatment approaches. Currently the advantage for testing is primarily limited to asymptomatic family members who carry FVL and who have had deep vein thrombosis. Close relatives who also carry the mutated gene might benefit from prophylactic anticoagulation when their risk of thrombosis is increased by temporary factors such as surgery. CONCLUSIONS: Nurses are in a unique position to provide accurate information and counseling when patients and their family members are presented with the results of thrombophilia testing.     

A pilot study of central venous catheter survival in cancer patients using low-molecular-weight heparin (dalteparin) and warfarin without catheter removal for the treatment of upper extremity deep vein thrombosis (The Catheter Study)

BACKGROUND: Central venous catheters in patients with cancer are associated with development of deep vein thrombosis (DVT); however, there is no accepted standard treatment. OBJECTIVES: To assess the safety and effectiveness of a management strategy for central venous catheter-related DVT in cancer patients consisting of dalteparin and warfarin without the need for line removal. PATIENTS/METHODS: Patients older than 18 years of age with an active malignancy and who had symptomatic, acute, objectively documented UEDVT were eligible. Patients were treated with dalteparin 200 IU kg(-1) per day for 5-7 days and warfarin with a target International Normalized Ratio of 2.0-3.0. Patients were followed for 3 months for recurrent venous thromboembolism, major hemorrhage and survival of the central venous catheter. RESULTS: There were 74 patients (48 males). The average age was 58 years. There were no episodes of recurrent venous thromboembolism and three (4%) major bleeds. No lines were removed because of infusion failure or recurrence/extension of DVT. CONCLUSION: Treatment of UEDVTs secondary to central catheters in cancer patients with standard dalteparin/warfarin can allow the central line to remain in situ with little risk of line failure or recurrence/extension of the DVT.     

Hormonal factors and risk of recurrent venous thrombosis: the Prevention of Recurrent Venous Thromboembolism trial

BACKGROUND: In some but not all studies, men with venous thrombosis had a higher risk of recurrence than women. Information on women with initial hormone-related thrombosis is scant. OBJECTIVE: We assessed the incidence of recurrent thrombosis by gender, and among women using exogenous hormones or pregnant/postpartum at the time of index thrombosis. PATIENTS/METHODS: A total of 508 men and women with one or more previous venous thrombosis episodes were observed while participating in a randomized trial of low-intensity warfarin or placebo for 2.1 years. Index thrombosis events during treatment with postmenopausal hormones, oral contraceptives, or during pregnancy, or the puerperium were considered to be hormone-related events. RESULTS: Among 268 men the 3-year probability of recurrent thrombosis was 18.4% (95% confidence intervals; CI 12.3-24.4). Among 109 women without hormone-related thrombosis, the rate was 15.0% (95% CI 6.3-23.8). Among 129 women with hormone-related thrombosis, the rate was 5.0% (95% CI 1.1-8.9). Adjusting for other risk factors and treatment assignment, women had a 39% lower thrombosis recurrence risk than men: hazard ratio (HR) 0.61 (95% CI 0.34-1.08). Women with hormone-related thrombosis had a 58% lower risk than men: HR 0.42 (95% CI 0.19-0.97); and a 46% lower recurrence risk than other women; HR 0.54 (95% CI 0.19-1.54). Women without hormone-related index events had a recurrence rate similar to men; HR 0.83 (95% CI 0.42-1.66). CONCLUSIONS: In this trial population, women had a lower risk of recurrent venous thrombosis than men. This difference was explained by a low risk of recurrence among women with hormone-related index thrombosis.     

High factor VIII and the risk of venous thromboembolism

There is now convincing evidence that a high level of coagulation factor VIII is an important risk factor for venous thromboembolism. A factor VIII plasma concentration above 1500 IU/l is associated with an almost 5-fold risk for a first episode of venous thrombosis. In thrombosis patients high factor VIII has been shown to persist over time and is not related to an acute phase reaction. High factor VIII is also an important risk factor for recurrence of venous thrombosis. In a prospective cohort study factor VIII levels exceeding the 90th percentile of the patient population conferred an almost 7-fold risk of recurrent venous thrombosis. The pathomechanisms leading to venous thrombosis in patients with high factor VIII are still unclear. In many patients, however, a biochemically detectable hypercoagulable state (as represented by elevated levels of the coagulation activation marker prothrombin thrombin fragment F1.2) was demonstrated. The optimal duration of secondary thromboprophylaxis for patients with high factor VIII levels is uncertain. We currently perform an interventional trial comparing conventional to extended anticoagulation. Reduction of factor VIII by administration of a non-selective ss-receptor blocker might be a promising therapeutic concept which is currently under investigation.     

Pregnancy-associated thrombosis

Venous thromboembolism (VTE) occurs infrequently but is a leading cause of illness and death during pregnancy and the puerperium. In the general population the incidence of pregnancy associated VTE is approximately 1 in 1500 deliveries The risk of VTE is five times higher in a pregnant than in a non-pregnant woman. Postpartum the VTE-risk is even higher. Women with congenital abnormalities or persistent presence of antiphospholipid antibodies have an increased risk of VTE during pregnancy and the puerperium. In individuals with well defined hereditary thrombosis risk factors, such as the factor V:R506Q mutation, the factor II:G20210A variation, antithrombin-deficiency or protein C-deficiency, a relative risk of pregnancy associated VTE between 3.4 and 15.2 has been found. Women with previous VTE have an approximately 3.5 fold increased risk of recurrent VTE during pregnancy compared to non-pregnant periods. Our ability to diagnose pregnancy-associated VTE clinically is generally poor, since dyspnea, tachypnea, swelling and discomfort in the legs are common. Objective diagnosis is essential for treatment decisions. Exposure to radiation of less than 50,000 microGy (5 rad) has not been associated with a significant risk of fetal injury Therefore, besides sonography, routine diagnostic procedures should be performed, if clinically necessary. Heparin does not cross the placenta and is therefore the anticoagulant of choice. In case of acute thrombosis during pregnancy, treatment is performed like in nonpregnant patients. There is ongoing debate, whether or not pregnant women with previous venous thrombosis should routinely receive prophylactic anticoagulation. In patients who have hereditary antithrombin deficiency, antiphospholipid antibodies, a combined abnormality or a history of a severe thrombotic event (pulmonary embolism, extended deep vein thrombosis) should be advised to use prophylactic heparin during pregnancy, starting during the first trimester. Post partum prophylaxis should be given in all women with an increased risk for VTE.     

ACE DD genotype: an independent predisposition factor to venous thromboembolism

BACKGROUND: The renin angiotensin system affects haemostasis through different mechanisms; data on the possible role of angiotensin-converting enzyme I/D polymorphism in the pathogenesis of deep venous thrombosis are conflicting, and no information is available regarding the A1166C polymorphism of the angiotensin type 1 receptor gene. In order to investigate this issue, angiotensin-converting enzyme and AT1R polymorphisms were genotyped in 336 consecutive venous thromboembolism patients and 378 controls. MATERIALS AND METHODS: Haemostasis-related risk factors have been evaluated by routine tests. Factor V Leiden, Factor II (G20210A), angiotensin-converting enzyme (I/D), and angiotensin type 1 receptor (A1166C) polymorphisms have been identified by molecular analysis. RESULTS: We documented a significant association between angiotensin-converting enzyme DD genotype and venous thromboembolism (OR=2.19 95%CI 1.51-3.17 adjusted for acquired and haemostasis-related risk factors, P<0.0001); in patients with haemostasis-related risk factors, angiotensin-converting enzyme DD genotype modified the risk of venous thromboembolism in hyperhomocysteinaemic and Factor V Leiden patients and was associated with the risk of recurrent venous thromboembolism (OR=1.83 95%CI 1.06-3.17 P=0.03). In patients without haemostasis-related risk factors the angiotensin-converting enzyme DD genotype was still an independent predictor of venous thromboembolism (OR=3.29 95%CI 2.17-4.98 adjusted for acquired risk factors, P<0.0001). No significant association between the angiotensin type 1 receptor CC genotype and venous thromboembolism was found. CONCLUSIONS: This study shows that angiotensin-converting enzyme DD genotype represents a susceptibility marker of thrombosis in subjects apparently without predisposing factors and traditional thrombophilic alterations, and increases the risk of venous thromboembolism in subjects in whom a thrombogenic condition occurs. Moreover, angiotensin-converting enzyme DD genotype may be considered a new predisposing factor to venous thromboembolism recurrence.     

Management of thrombophilia

Summary.  It is now possible to identify acquired and hereditary risk factors in a substantial percentage of patients presenting with a venous thrombotic event. Discovery of the factor V Leiden and prothrombin G20210A mutations has greatly increased the percentage of patients in whom venous thrombosis can be attributed to hereditary thrombophilia. There is, however, considerable uncertainty as to how this information should be used in patient management. Although prolonged anticoagulation at an international normalized ratio of 2–3 is highly effective in preventing thrombotic recurrences, this benefit is partially offset by major bleeding which occurs at an average rate of 2%−3% per year. A decision as to the overall benefit of extended anticoagulation in the individual patient requires assessment of the risk of recurrence in the absence of treatment vs. the bleeding risk associated with prolonged anticoagulation. Low-intensity warfarin therapy or novel anticoagulants such as oral direct thrombin inhibitors may prove effective strategies for preventing recurrent venous thromboembolism in patients with thrombophilia.     

Venous thromboembolism prophylaxis and treatment in patients with acute stroke and traumatic brain injury

PURPOSE OF REVIEW: Patients with acute stroke and traumatic brain injury are at risk to develop venous thromboembolism. This review analyzes the available literature to propose guidelines for the prevention and treatment of venous thromboembolism in these groups of patients. RECENT FINDINGS: In acute ischemic stroke, low-dose low-molecular-weight heparin has the best benefit-risk ratio to prevent venous thromboembolism. Patients with primary intracerebral hemorrhage and traumatic brain injury should receive intermittent pneumatic compression, followed by low-dose low-molecular-weight heparin or unfractioned heparin 3-4 days after stroke onset or 24 h after injury or surgery, respectively, and after cessation of bleeding. Concerning treatment, in patients with deep-vein thrombosis lower doses of heparin are indicated to prevent pulmonary embolism, and a vena cava filter should be considered. In patients with pulmonary embolism, treatment could be more aggressive, because of a high mortality risk. SUMMARY: Adequate prevention of venous thromboembolism with intermittent pneumatic compression or pharmacological prophylaxis is important. The best treatment of venous thromboembolism remains unclear. In case of pulmonary embolism, more aggressive treatment is warranted.     

Update on extended treatment for venous thromboembolism

Abstract

The importance of assessing the probability of venous thromboembolism recurrence, a condition that includes deep vein thrombosis and pulmonary embolism, lies in the fact that it is the most important factor in deciding the duration of anticoagulant treatment. Risk of recurrence depends mostly on the presence of a risk factor for developing venous thromboembolism, with patients with unprovoked events being at the higher risk of recurrence. The risk of recurrence needs to be balanced with the risk of bleeding and the potential severity of these thrombotic and hemorrhagic events. In patients with an unprovoked venous thromboembolism who complete treatment for the acute (first 10 days) and post-acute phase of the disease (from day 10 to 3–6 months), the decision has to be made regarding prolonged antithrombotic therapy to prevent recurrences. The main goal of extended treatment is preventing recurrences with a safety profile in terms of bleeding risk. Many therapeutic options are now available for these patients, including antiplatelet therapy with aspirin or direct oral anticoagulants. Moreover, apixaban and rivaroxaban at prophylactic doses have demonstrated efficacy in preventing recurrences with a low risk of bleeding.

• Key messages

• Extending treatment (longer than 3–6 months) is challenging in patients with venous thromboembolism (VTE) and depend on the risk of venous thromboembolism recurrence, the bleeding risk and patient and physician preferences.

• Anticoagulation treatment should be stopped in patients with provoked VTE and in those with unprovoked VTE and a high bleeding risk after an initial period of 3–6 months.

• There are some therapeutic alternatives (including Aspirin and low dose of some NOACs) to reduce venous thromboembolism recurrence risk in patients with unprovoked VTE and a low bleeding risk for extended treatment of VTE (after an initial period of 3–6 months).