Patients with a first symptomatic unprovoked deep vein thrombosis are at higher risk of recurrent venous thromboembolism than patients with a first unprovoked pulmonary embolism

Summary. Background: Previous studies are mixed as to whether patients with unprovoked pulmonary embolism (PE) have a higher rate of venous thromboembolism (VTE) recurrence after anticoagulation is discontinued than patients with unprovoked deep vein thrombosis (DVT). Objectives: To determine whether patients with unprovoked PE have a higher rate of VTE recurrence than patients with unprovoked DVT in a prospective multicenter cohort study. Patients/Methods: Six hundred and forty‐six patients with a first episode of symptomatic unprovoked VTE were treated with heparin and subsequent oral anticoagulation for 5–7 months, and were followed every 6 months for recurrent VTE after their anticoagulant therapy was discontinued. Results: Of 646 patients, 194 had isolated PE, 339 had isolated DVT, and 113 had both DVT and PE. After a mean of 18 months of follow‐up, there were 91 recurrent VTE events (9.5% annualized risk of recurrent VTE in the total population). The crude recurrent VTE rate for the isolated PE, isolated DVT and DVT and PE groups were 7.7%, 16.5% and 17.7%, respectively. The relative risk of recurrent VTE for isolated DVT vs. isolated PE was 2.1 (95% confidence interval 1.2–3.7). Conclusions: This study has demonstrated that patients with a first episode of unprovoked isolated DVT are 2.1 times more likely to have a recurrent VTE episode than patients with a first episode of unprovoked isolated PE. These findings need to be considered when determining the optimal duration of anticoagulant therapy for patients with unprovoked VTE.     

What happens after venous thromboembolism?

Summary.  Venous thromboembolism (VTE) comprises deep vein thrombosis (DVT) with or without symptomatic pulmonary embolus (PE). The incidence of a first episode of VTE is 1.5 per 1000 person-years [ 1 ] ( J Thromb Haemost , 2007; 5 :692–9) with a per-person lifetime incidence of 5% [ 2 ] ( Arch Intern Med 1998;158:585–93). The risk of recurrence after DVT and PE is similar but the pattern of recurrence tends to reflect the initial event, for example recurrence with PE is more common in patients with previous PE [ 3 ] ( Circulation 2003; 107 :122–30). At least 50% of patients, who present with symptomatic DVT, have asymptomatic PE and conversely, a majority presenting with symptomatic PE have asymptomatic DVT [ 3 ] ( Circulation 2003; 107 :122–30). This suggests that whilst DVT and PE are manifestations of the same pathology, the phenotypic expression of the disease is predetermined. This may be an important consideration for long-term anticoagulant therapy as the risk of fatal PE is the greatest in patients with previous PE [ 4 ] ( Ann Intern Med 2007; 147 :766–74). At present, the only factor reported to be associated with the pattern of VTE is the factor V Leiden mutation [ 5 ] ( Thromb Haemost 1999; 81 :345–8). This suggests that the kinetics of thrombin generation and the resulting fibrinolytic response may influence clot structure and likelihood of embolization.     

Management of superficial vein thrombosis

Superficial vein thrombosis (SVT) is less well studied than deep vein thrombosis (DVT), because it has been considered to be a minor, self‐limiting disease that is easily diagnosed on clinical grounds and that requires only symptomatic relief. The most frequently involved sites of the superficial vein system are the lower limbs, especially the saphenous veins, mostly in relation to varicosities. Lower‐limb SVT shares the same risk factors as DVT; it can propagate into the deep veins, and have a complicated course with pulmonary embolism. Clinical diagnosis may not be accurate, and ultrasonography is currently indicated for both confirmation and evaluation of SVT extension. Treatment aims are symptom relief and prevention of venous thromboembolism (VTE) in relation to the thrombotic burden. SVT of the long saphenous vein within 3 cm of the saphenofemoral junction (SFJ) is considered to be equivalent to a DVT, and thus deserving of therapeutic anticoagulation. Less severe forms of lower‐limb SVT not involving the SFJ have been included in randomized clinical trials of surgery, compression hosiery, non‐steroidal anti‐inflammatory drugs, unfractionated heparin, and low molecular weight heparins, with inconclusive results. The largest randomized clinical trial available, on 3004 patients with lower‐limb SVT not involving the SFJ, showed that fondaparinux 2.5 mg once daily for 6 weeks is more effective than placebo in reducing the risk of the composite of death from any cause and symptomatic VTE (0.9% versus 5.9%). Further studies are needed to define the optimal management strategies for SVT of the lower limbs and other sites, such as the upper limbs.     

Balancing risks and benefits of extended anticoagulant therapy for idiopathic venous thrombosis

Summary.  About half of the patients with a first idiopathic proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) are expected to have a recurrent episode of venous thromboembolism (VTE) within 10 years of stopping therapy, and randomized trials have shown that this group of patients benefit from long-term anticoagulant therapy. High risks for bleeding and patient preference are compelling reasons not to treat such patients long-term. Although a number of factors are associated with a reduced risk of recurrence, they require further validation before it is appropriate to routinely stop anticoagulants after 3 months in patients with idiopathic proximal DVT or PE.     

Does the clinical presentation and extent of venous thrombosis predict likelihood and type of recurrence? A patient‐level meta‐analysis

Summary. Aim: To determine if the mode of presentation of venous thromboembolism (VTE), as deep vein thrombosis (DVT) or pulmonary embolism (PE), predicts the likelihood and type of recurrence. Methods: We carried out a patient‐level meta‐analysis of seven prospective studies in patients with a first VTE who were followed after anticoagulation was stopped. We used Kaplan‐Meier analysis to determine the cumulative incidence of recurrent VTE according to mode of presentation, and multivariable Cox regression to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for mode of and extent of DVT as potential risk factors for recurrence. Results: The 5‐year cumulative rate of recurrent VTE in 2554 patients was 22.6%. In 869 (36.1%) patients with PE, the 5‐year rate of any recurrence (DVT or PE) was 22.0%, and recurrence as PE was 10.6%. In 1365 patients with proximal DVT, the 5‐year recurrence rate was 26.4%, and recurrence with PE was 3.6%. The risk of recurrence as PE was 3.1‐fold greater in patients presenting with symptomatic PE than in patients with proximal DVT (HR, 3.1; 95% CI, 1.9–5.1). Patients with proximal DVT had a 4.8‐fold higher cumulative recurrence rate than those with distal DVT (HR, 4.8; 95% CI, 2.1–11.0). Conclusion: Whilst DVT and PE are manifestations of the same disease, the phenotypic expression is predetermined. Patients presenting with PE are three times more likely to suffer recurrence as PE than patients presenting with DVT. Patients presenting with calf DVT are at low risk of recurrence and at low risk of recurrence as PE.     

Diagnosis of deep vein thrombosis,and prevention of deep vein thrombosis recurrence and the post-thrombotic syndrome in the primary care medicine setting anno 2014

The requirement for a safe diagnostic strategy of deep vein thrombosis (DVT) should be based on an overall objective post incidence of venous thromboembolism (VTE) of less than 1% during 3 mo follow-up. Compression ultrasonography (CUS) of the leg veins has a negative predictive value (NPV) of 97%-98% indicating the need of repeated CUS testing within one week. A negative ELISA VIDAS safely excludes DVT and VTE with a NPV between 99% and 100% at a low clinical score of zero. The combination of low clinical score and a less sensitive D-dimer test (Simplify) is not sensitive enough to exclude DVT and VTE in routine daily practice. From prospective clinical research studies it may be concluded that complete recanalization within 3 mo and no reflux is associated with a low or no risk of PTS obviating the need of MECS 6 mo after DVT. Partial and complete recanalization after 3 to more than 6 mo is usually complicated by reflux due to valve destruction and symptomatic PTS. Reflux seems to be a main determinant for PTS and DVT recurrence, the latter as a main contributing factor in worsening PTS. This hypothesis is supported by the relation between the persistent residual vein thrombosis (RVT = partial recanalization) and the risk of VTE recurrence in prospective studies. Absence of RVT at 3 mo post-DVT and no reflux is predicted to be associated with no recurrence of DVT (1.2%) during follow-up obviating the need of wearing medical elastic stockings and anticoagulation at 6 mo post-DVT. The presence or absence of RVT but with reflux at 3 to 6 mo post-DVT is associated with both symptomatic PTS and an increased risk of VTE recurrence in about one third in the post-DVT period after regular discontinuation of anticoagulant treatment. To test this hypothesis we designed a prospective DVT and postthrombotic syndrome (PTS) Bridging the Gap Study by addressing at least four unanswered questions in the treatment of DVT and PTS. Which DVT patient has a clear indication for long-term compression stocking therapy to prevent PTS after the initial anticoagulant treatment in the acute phase of DVT? Is 3 mo the appropriate point in time to determine candidates at risk to develop DVT recurrence and PTS? Which high risk symptomatic PTS patients need extended anticoagulant treatment?     

The first ambulatory screening on thromboembolism: a multicentre, cross-sectional, observational study on risk factors for venous thromboembolism

Summary.  Objectives:  To assess the prevalence of risk factors for venous thromboembolism (VTE) and the prevalence of recent (<1 year) VTE [including superficial vein thrombosis (SVT), deep vein thrombosis (DVT) and pulmonary embolism (PE)] amongst patients attending general practitioner (GP) surgeries. Design:  Multicentre, cross-sectional, observational study. Setting:  A total of 1536 GP surgeries. Participants:  A total of 15 180 adult, co-operative subjects, who had consulted their GP for a health disorder and signed the informed consent form. Interventions:  None. Main outcome measures:  Prevalence of known VTE risk factors graded according to importance and prevalence of recent (<1 year) VTE events (including SVT), based on interviews. Results:  About 1:5 patients had at least one strong risk factor and about 1:20 had at least two risk factors, with no difference between sexes. The prevalence of strong risk factors increased with age. Most were related to medical conditions: history of SVT and/or DVT/PE, heart failure and malignancy. About 3:4 women and 2:3 men had at least one moderate to weak risk factor; nearly 1:2 women and 1:3 men had at least two moderate to weak risk factors. The most common were: history of VTE, smoking, history of miscarriage, estrogen therapy, obesity, and varicose veins. Overall, 80% women and 67% men had at least one risk factor, and 50% women and 35% men had at least two risk factors. The prevalence of recent (<1 year) VTE was 3.4% in women and 2.4% in men, and increased with age. The majority of cases were SVT in both sexes (2.5% in women and 1.5% in men). Conclusions:  The prevalence of risk factors for VTE amongst patients attending GP surgeries is high. GPs should bear this in mind during their daily practice.     

Incidence of cancer after a first episode of idiopathic venous thromboembolism treated with 3 months or 1 year of oral anticoagulation

Summary.  Background : A prolonged treatment with oral anticoagulants has been claimed to reduce the incidence of newly diagnosed cancer in the long-term follow-up of patients with venous thromboembolism. Objectives : In a multicenter prospective study we assessed the incidence of newly diagnosed clinically overt cancer in patients with a first episode of idiopathic venous thromboembolism (VTE) treated with oral anticoagulants for 3 months or 1 year. Patients and methods : Consecutive patients with an idiopathic venous thromboembolism who had completed 3 months of oral anticoagulant therapy without having a recurrence, bleeding or newly diagnosed cancer were randomized to discontinue oral anticoagulant therapy or to continue it for nine additional months. Idiopathic venous thromboembolism was defined as thrombosis occurring in the absence of known cancer, known thrombophilia, or temporary risk factors for venous thromboembolism. All patients were followed up for at least 1 year after randomization. Results : A total of 429 patients, 265 patients with DVT and 164 with PE, were followed up for an average of 43.7 months after randomization. A newly diagnosed cancer occurred in 32 patients (7.5%), 13 (6.2%) of the 210 patients treated for 3 months and 19 (8.7%) of the 219 patients treated for 1 year (RR = 0.71, 95% confidence interval 0.36–1.41). Conclusions : The incidence of newly diagnosed clinically overt cancer is not reduced in patients with idiopathic venous thromboembolism treated with 1-year anticoagulant treatment compared with patients treated for 3 months.     

Clinical course of patients with symptomatic isolated superficial vein thrombosis: the ICARO follow‐up study

Essentials

• Late sequelae of isolated superficial vein thrombosis (iSVT) have rarely been investigated.
• We studied 411 consecutive outpatients with acute iSVT with a median follow‐up of three years.
• Male sex and cancer are risk factors for future deep vein thrombosis or pulmonary embolism.
• Patients without cancer appear to be at a negligible risk for death.

Summary

Background

Studies of long‐term thromboembolic complications and death following acute isolated superficial vein thrombosis (iSVT) of the lower extremities are scarce.

Objectives

To investigate the course of iSVT in the setting of an observational multicenter study.

Methods

We collected longitudinal data of 411 consecutive outpatients with acute, symptomatic, objectively diagnosed iSVT who were previously included in the cross‐sectional ICARO study. Four patients followed for < 30 days and 79 with concomitant deep vein thrombosis (DVT) or pulmonary embolism (PE) were excluded from the present analysis. The primary outcome was symptomatic DVT or PE. The safety outcomes were major bleeding and all‐cause death.

Results

The median follow‐up time was 1026 days (interquartile range 610–1796). Symptomatic DVT/PE occurred in 52 (12.9%) patients, giving annualized rates of 1.3% (95% confidence interval [CI] 0.3–3.9%) on anticoagulant treatment and 4.4% (95% CI 3.2–5.8%) off anticoagulant treatment. Male sex (adjusted hazard ratio [HR] 2.03 [95% CI 1.16–3.54]) and active solid cancer (adjusted HR 3.14 [95% CI 1.11–8.93]) were associated with future DVT/PE, whereas prior DVT/PE failed to show significance, most likely because of bias resulting from prolonged anticoagulant treatment. Three major bleeding events occurred on treatment, giving an annualized rate of 1.4% (95 CI 0.3–4.0%). Death was recorded in 16 patients (annualized rate: 1.1% [95% CI 0.6–1.7%]), and was attributable to cancer (n = 8), PE (n = 1), cardiovascular events (n = 3), or other causes (n = 4).

Conclusions

The long‐term risk of DVT/PE after anticoagulant discontinuation for acute iSVT is clinically relevant, especially in males and in the presence of active cancer. The risk of death appears to be negligible in patients without cancer.     

Type and location of venous thromboembolism in patients with factor V Leiden or prothrombin G20210A and in those with no thrombophilia

BACKGROUND: Patients with factor (F) V Leiden or the prothrombin G20210A polymorphism are at increased risk of developing deep vein thrombosis (DVT). On the other hand, the risk of developing pulmonary embolism (PE) appears to be low in carriers of FV Leiden, perhaps because of a lower tendency to develop iliofemoral DVT than non-carriers. For prothrombin G20210A, data are scanty and controversial. METHODS: The clinical manifestations (isolated DVT, DVT and PE, and isolated PE), the extension of DVT, and the presence of transient risk factors were retrospectively investigated in 115 patients with heterozygous FV Leiden, 87 with prothrombin G20210A and 200 with no thrombophilia marker. RESULTS: Isolated symptomatic PE was less prevalent in patients with FV Leiden (6%) than in those with prothrombin G20210A (21%) and no thrombophilia (23%) (P > 0.0001). The rate of distal DVT was higher in patients with no thrombophilia (16% vs. 7% for FV Leiden and 6% for prothrombin G20210A) (P = 0.02). No difference in the incidence of PE from distal and proximal DVT, the extension of proximal DVT and the type of transient risk factors for venous thromboembolism (VTE) was found in the three groups. Patients with prothrombin G20210A had a younger age at their first VTE (24 years, P < 0.0001) and a higher rate of DVT accompanying PE (P = 0.04) than those with FV Leiden or no thrombophilia. CONCLUSIONS: Carriers of prothrombin G20210A, unlike those of FV Leiden, have an increased risk of developing isolated PE. This difference was not explained by a different rate of distal DVT, extension of proximal DVT, or distribution of transient risk factors in the two groups. Patients with prothrombin G20210A have more severe clinical manifestations than those with FV Leiden or no thrombophilia.     

Comparison of the clinical history of symptomatic isolated distal deep‐vein thrombosis vs. proximal deep vein thrombosis in 11 086 patients

Background: The clinical significance of symptomatic isolated distal deep vein thrombosis (DVT) is uncertain. Consequently, this leads to important disparities in its management. Objective: To examine the clinical history of isolated distal DVT and to compare it with that of proximal DVT. Methods: Using data from the international, prospective, RIETE registry on patients with confirmed symptomatic venous thromboembolism (VTE), we compared the risk factors and 3‐month outcome in patients with isolated distal DVT vs. proximal DVT. Results: Eleven thousand and eighty‐six patients with symptomatic DVT, but without pulmonary embolism, were included between 2001 and 2008; 1921 (17.3%) exhibited isolated distal DVT. Anticoagulant treatment was received by 89.1% (1680/1885) of isolated distal DVT and 91.8% (7911/8613) of proximal DVT patients for the entire follow‐up period. Isolated distal DVTs were more associated with transient risk factors (i.e. recent travel, hospitalization, recent surgery), whereas proximal DVTs were more associated with chronic states (i.e. ≥75 years or with active cancer). At 3 months, major bleeding rate was lower in patients with isolated distal DVT (1.0% vs. 2.2%, P < 0.01), whereas VTE recurrence rate was equivalent (2.0% vs. 2.7%, P = 0.07). The mortality rate was lower in patients with isolated distal DVT (2.7% vs. 7.5%; P < 0.001); this was mainly due to a lower rate of non‐VTE‐related deaths (2.2% vs. 6.3%; P < 0.001). Active cancer was the main predictive factor of death in patients with isolated distal DVT. Conclusions: Proximal and isolated distal DVT patients differ in terms of risk factors and clinical outcomes, suggesting different populations. In the short term, the life expectancy of patients with isolated distal DVT depended chiefly on their cancer status.     

Guidelines and the use of inferior vena cava filters: a review of an institutional experience

Summary.  Background and objectives:  Based on the American College of Chest Physicians 2004 antithrombotic therapy for venous thromboembolism (VTE) and the Eastern Association for the Surgery of Trauma 2002 guidelines, placement of an inferior vena cava (IVC) filter is indicated in patients who either have, or are at high risk for, VTE, but have a contraindication or failure of anticoagulation. Our aim is to compare clinical characteristics and outcomes of patients receiving IVC filters within-guidelines (WG) and outside-of-guidelines (OOG). Methods:  The 558 patients who received an IVC filter were divided into two groups called WG or OOG. The WG group met the criteria described above and the OOG group did not have a contraindication to or a failure of anticoagulation. Results:  The WG group had 362 patients and the OOG group had 196 patients. The OOG group had one (0.5%) patient with post-filter pulmonary embolism (PE), two (1%) with IVC thrombosis, and seven (3.6%) with deep vein thrombosis (DVT). The WG group had five (1.4%) patients with post-filter PE, 13 (3.6%) with IVC thrombosis, and 34 (9.4%) with DVT. All patients who developed post-filter PE had a DVT before filter placement, and patients who did not have a prior VTE event were at a significantly lower risk of developing post-filter IVC thrombosis and PE. Conclusion:  Our data do not support the use of an IVC filter outside of guidelines in patients without prior VTE who can tolerate anticoagulation because of the low risk of developing PE.     

Secondary prophylaxis of venous thromboembolism

Making decisions about any modality of secondary prophylaxis in patients with venous thromobembolism (VTE) has to balance the risk of bleeding induced by anticoagulants against the benefit of reducing the risk of recurrent disease. It has to be kept in mind that the magnitude of risk is not only defined by the number of events per time period but also by the impact of the event on the fate of the patient. With standard intensity vitamin K antagonists (VKA), the risk of bleeding is more closely related to comorbidities than to other factors, eg age. The risk of VTE recurrence differs largely between patient groups. The criterion of presence or absence of a permanent or transient clinical trigger factor for the actual VTE episode has a greater impact than an abnormal result in thrombophilia testing. The standard period of secondary prophylaxis for proximal DVT and for PE is three to six months. The concept of prolonging this period for several months according to the risk of recurrence is seriously challanged by the observation that the prolongation period seems to delay recurrencies rather than truly avoiding them. For this reason, patients who clearly are threatened by recurrent episodes should receive indefinitive secondary prophylaxis. This is the case for cancer patients, patients with the antiphospholipid syndrome, and those who belong to families with severe and symptomatic protein C, protein S, or antithrombin deficiencies. Patients with recurrent VTE, with idiopathic VTE, or with combined thrombophilic conditions may only benefit from indefinitive secondary prophylaxis if the bleeding risk of the anticoagulant regimen under consideration is very low.     

Rivaroxaban for the Treatment of Pulmonary Embolism

With the advent of new oral anticoagulants (NOACs) for the treatment of deep-vein thrombosis (DVT) and/or pulmonary embolism (PE), a new era of oral anticoagulation for patients with venous thromboembolism (VTE) has begun. Rivaroxaban is the first NOAC to receive regulatory approval for the acute and continued treatment of DVT and PE, and for the secondary prevention of VTE. Here, the clinical trials of rivaroxaban in patients with VTE are reviewed, and the clinical use of rivaroxaban for patients with PE is discussed. Even though rivaroxaban will facilitate the therapeutic management of PE, its use in specific clinical situations needs further study.     

Incidence of symptomatic venous thromboembolism following hematopoietic stem cell transplantation

Summary.  Background: The incidence of symptomatic venous thromboembolism (VTE) following hematopoietic stem cell transplantation (HSCT) is not well described, particularly with increased use of ambulatory care in the transplant setting. Methods: A retrospective analysis involving 589 patients (382 autologous HSCT, 207 allogeneic HSCT) undergoing transplantation between 2000 and 2005 in a single Canadian institution was undertaken to identify the incidence of proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) in HSCT patients. Results: The total 1-year incidence of symptomatic VTE was 3.7% [95% confidence interval (CI) 2.5–5.6]. Among the HSCT patients, 7/589 (1.2%, 95% CI  0.6–2.4) developed symptomatic non-catheter-related VTE following HSCT (four PE and three DVT). All VTE events occurred after hematopoietic engraftment. Patients undergoing autologous HSCT did not receive thromboprophylaxis, whereas most patients undergoing allogeneic HSCT (79.7%) received enoxaparin 20 mg daily for the prevention of veno-occlusive disease of the liver, starting 6 ± 3 days before transplantation for a mean of 22 ± 14 days. Conclusion: HSCT patients have a high incidence of VTE. Thromboprophylaxis should potentially be considered in these patients. However, future studies assessing the risk and benefits of thromboprophylaxis are needed in this specific population.     

Treatment and secondary prevention of venous thromboembolism in cancer patients. Current strategies and new therapeutic options

Cancer is a major and independent risk factor of venous thromboembolism (VTE). In clinical practice, a high number of VTE events occurs in patients with cancer, and treatment of cancer-associated VTE differs in several aspects from treatment of VTE in the general population. However, treatment in cancer patients remains a major challenge, as the risk of recurrence of VTE as well as the risk of major bleeding during anticoagulation is substantially higher in patients with cancer than in those without cancer. In several clinical trials, different anticoagulants and regimens have been investigated for treatment of acute VTE and secondary prophylaxis in cancer patients to prevent recurrence. Based on the results of these trials, anticoagulant therapy with low-molecular-weight heparins (LMWH) has become the treatment of choice in cancer patients with acute VTE in the initial period and for extended and long-term anticoagulation for 3-6 months. New oral anticoagulants directly inhibiting thrombin or factor Xa, have been developed in the past decade and studied in large phase III clinical trials. Results from currently completed trials are promising and indicate their potential use for treatment of VTE also in cancer patients. However, the role of the new oral thrombin and factor Xa inhibitors for VTE treatment in cancer patients still has to be clarified in further studies specifically focusing on cancer-associated VTE. This brief review will summarize the current strategies of initial and long-term VTE treatment in patients with cancer and discuss the potential use of the new oral anticoagulants.     

Combined computed tomography venography and pulmonary angiography for the diagnosis PE and DVT in the ED

The purpose of this study is to evaluate the usefulness of combined computed tomography venography and pulmonary angiography (CTVPA) in the diagnosis of venous thromboembolic (VTE) disease in the emergency department (ED). CTVPA images and clinical data of 73 nonselected patients with suspected pulmonary embolism (PE) and/or deep venous thrombosis (DVT) were retrospectively assessed. CTVPA correctly identified 33 of 34 patients with VTE disease, including 7 patients with PE alone, 11 patients with DVT alone, and 16 patients with both PE and DVT. Among the 27 patients with DVT, CTVPA disclosed thrombosis involving the abdominal and pelvic veins in 4 patients, and isolating to the inferior vena cava and iliac vein in one patient. CTVPA showed high accuracy in the diagnosis of both PE and DVT, in comparison with lower extremity venous sonography and ventilation-perfusion scintigraphy. In 26 (66%) of the 39 patients without of evidence VTE, CTVPA provided important ancillary information that suggests additional or alternative diagnoses. CTVPA is therefore an appropriate single diagnostic tool for evaluation VTE disease in the ED.     

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.