Venous thromboembolism: risk factors for recurrence

Sex-specific effect of CPB2 Ala147Thr but not Thr325Ile variants on the risk of venous thrombosis: A comprehensive meta-analysis

BACKGROUND

Thrombin activatable fibrinolysis inhibitor (TAFI), encoded by the Carboxypeptidase B2 gene (CPB2), is an inhibitor of fibrinolysis and plays a role in the pathogenesis of venous thrombosis. Experimental findings support a functional role of genetic variants in CPB2, while epidemiological studies have been unable to confirm associations with risk of venous thrombosis. Sex-specific effects could underlie the observed inconsistent associations between CPB2 genetic variants and venous thrombosis.

METHODS

A comprehensive literature search was conducted for associations between Ala147Thr and Thr325Ile variants with venous thrombosis. Authors were contacted to provide sex-specific genotype counts from their studies. Combined and sex-specific random effects meta-analyses were used to estimate a pooled effect estimate for primary and secondary genetic models.

RESULTS

A total of 17 studies met the inclusion criteria. A sex-specific meta-analysis applying a dominant model supported a protective effect of Ala147Thr on venous thrombosis in females (OR = 0.81, 95%CI: 0.68,0.97; p = 0.018), but not in males (OR = 1.06, 95%CI:0.96-1.16; p = 0.263). The Thr325Ile did not show a sex-specific effect but showed variation in allele frequencies by geographic region. A subgroup analysis of studies in European countries showed decreased risk, with a recessive model (OR = 0.83, 95%CI:0.71-0.97, p = 0.021) for venous thrombosis.

CONCLUSIONS

A comprehensive literature review, including unpublished data, provided greater statistical power for the analyses and decreased the likelihood of publication bias influencing the results. Sex-specific analyses explained apparent discrepancies across genetic studies of Ala147Thr and venous thrombosis. While, careful selection of genetic models based on population genetics, evolutionary and biological knowledge can increase power by decreasing the need to adjust for testing multiple models.

Characteristics of provoked deep venous thrombosis in a tertiary care center

OBJECTIVE

Provoked deep venous thrombosis (DVT) is precipitated by a specific event. This paper compares the characteristics of provoked DVT in patients with transient risk (TR) factors and patients with continuous risk (CR) factors.

METHODS

A retrospective review of records of all consecutive patients diagnosed with DVT between January 2013 and August 2014 was performed. Patients with provoked DVT were included in the TR group if the provoking event resolved in 2 weeks and they did not have ongoing risk of thrombosis. Patients in the CR group had a provoked DVT with ongoing risk of thrombosis due to individual factors deemed to be ongoing risks of thrombosis, such as cancer, hypercoagulable disorder, and prolonged immobilization. Demographics, risk factors, association with pulmonary embolism (PE) and its severity, risk of recurrent venous thromboembolism (VTE), and mortality were compared between the two groups.

RESULTS

A total of 838 patients were diagnosed with DVT, and 50.7% (425) were provoked. There were 127 (29.9%) patients with TR and 298 (70.1%) with CR. TR patients were younger (60.4 ± 16.3 vs 65.9 ± 16.0; P = .001). TR was more likely to be provoked by surgery (70.9% vs 55.4%; P = .003), whereas CR was more likely to be provoked by immobilization (21.5% vs 12.6%; P = .032). CR patients were affected by cancer (48.7%) and hypercoagulable disorders (4.4%). TR patients were more likely to have calf DVTs (36.2% vs 26.2%; P = .047). There was a trend toward lower association with PE on presentation in TR (17.3% vs 21.1%; P = .072), but that did not reach statistical significance. However, TR factors were more likely to be associated with low-risk PE compared with CR factors (30.2% vs 54.6%; P = .040). After mean follow-up of 7.2 months, CR had higher risk of recurrent VTE (14.0% vs 6.8%; P = .045) and mortality (23.5% vs 7.1%; P < .0001).

CONCLUSIONS

Provoked DVT with CR factors affects older patients and is associated with high recurrence of VTE and mortality compared with provoked DVT with TR factors.

Direct oral anticoagulants and venous thromboembolism

Venous thromboembolism (VTE), consisting of deep vein thrombosis and pulmonary embolism, is a major clinical concern associated with significant morbidity and mortality. The cornerstone of management of VTE is anticoagulation, and traditional anticoagulants include parenteral heparins and oral vitamin K antagonists. Recently, new oral anticoagulant drugs have been developed and licensed, including direct factor Xa inhibitors (e.g. rivaroxaban, apixaban and edoxaban) and thrombin inhibitors (e.g. dabigatran etexilate). This narrative review focusses on the characteristics of these direct anticoagulants and the main results of published clinical studies on their use in the prevention and treatment of VTE.

Thrombomodulin gene c.1418C>T polymorphism and risk of recurrent venous thromboembolism

Thrombomodulin gene (THBD) is a critical cofactor in protein C anticoagulant system. THBD c.1418C>T polymorphism is reported to be associated with higher risk of primary venous thromboembolism (VTE) but its role in VTE recurrence is unknown. The aim of this study was to investigate the role of THBD polymorphism in VTE recurrence. THBD c.1418C>T polymorphism was genotyped by using Taqman polymerase chain reaction in a prospective population based study of 1465 consecutive objectively verified VTE patients. Uni- and multivariate Cox regression were performed for the risk assessment of VTE recurrence. Patients who had VTE before inclusion or had recurrence or died during anticoagulant treatment were excluded. Among the remaining (N = 1046) patients, 126 (12.05 %) had VTE recurrence during the follow up period (from 1998 to 2008). THBD polymorphism was not significantly associated with risk of VTE recurrence in the univariate [Hazard ratio (HR) 1.11, 95 % confidence interval (CI) 0.78-1.59, p = 0.55] as well as the multivariate analysis adjusted for age, sex and thrombophilia (HR 1.11, 95 % CI 0.78-1.59, p = 0.54). Similarly, in unprovoked first VTE (n = 614), no association was observed between THBD polymorphism and risk of VTE recurrence (HR 1.22 and 95 % CI 0.78-1.89, p = 0.38). In this prospective study, our results do not suggest a predictive role for THBD c.1418C>T polymorphism in VTE recurrence.

Identification of potential drug targets based on a computational biology algorithm for venous thromboembolism

Venous thromboembolism (VTE) is a common, fatal and frequently recurrent disease. Changes in the activity of different coagulation factors serve as a pathophysiological basis for the recurrent risk of VTE. Systems biology approaches provide a better understanding of the pathological mechanisms responsible for recurrent VTE. In this study, a novel computational method was presented to identify the recurrent risk modules (RRMs) based on the integration of expression profiles and human signaling network, which hold promise for achieving new and deeper insights into the mechanisms responsible for VTE. The results revealed that the RRMs had good classification performance to discriminate patients with recurrent VTE. The functional annotation analysis demonstrated that the RRMs played a crucial role in the pathogenesis of VTE. Furthermore, a variety of approved drug targets in the RRM M5 were related to VTE. Thus, the M5 may be applied to select potential drug targets for combination therapy and the extended treatment of VTE.

Identification of Genetic Aberrations in Thrombomodulin Gene in Patients With Recurrent Venous Thromboembolism

Thrombomodulin (THBD) serves as a cofactor for thrombin-mediated activation of anticoagulant protein C pathway. Genetic aberrations in THBD have been studied in arterial and venous thrombosis. However, genetic changes in THBD and their role in the risk assessment of recurrent venous thromboembolism (VTE) are not well understood. The aim of the present study was to identify the genetic aberrations in THBD and their association with the risk of VTE recurrence in a prospective population-based study. We sequenced the entire THBD gene, first in selected patients with VTE (n = 95) by Sanger sequencing and later validated those polymorphisms with minor allele frequency (MAF) ≥5% in the whole study population (n = 1465 with the follow-up period of 1998-2008) by Taqman polymerase chain reaction. In total, we identified 8 polymorphisms in THBD, and 3 polymorphisms with MAF ≥5% were further validated. No significant association between THBD polymorphisms and risk of VTE recurrence on univariate or multivariate Cox regression analysis was found (hazard ratio [HR] = 0.89, 95% confidence interval [CI] = 0.62-1.28, HR = 1.27, 95% CI = 0.88-1.85, and HR = 1.15, 95% CI = 0.80-1.66 for THBD rs1962, rs1042580, and rs3176123 polymorphisms, respectively), adjusted for family history, acquired risk factors for VTE, location of deep vein thrombosis, and risk of thrombophilia. Subanalysis of patients with unprovoked first VTE also showed no significant association of identified THBD polymorphisms with the risk of VTE recurrence. Our results show that aberrations in the THBD gene may not be useful for the assessment of VTE recurrence; however, further studies with large sample size are needed to confirm these findings.

Factors determining altered perfusion after acute pulmonary embolism assessed by quantified single-photon emission computed tomography-perfusion scan

AIM OF THE STUDY:

The aim of the study was to analyze the evolution of perfusion (Q)-defects in patients treated for acute pulmonary embolism (PE), correlation with baseline parameters and evaluation of recurrence risk.

METHODS:

This is a single-center prospective observational cohort study in symptomatic normotensive PE. Comparison of the ventilation/perfusion single-photon emission computed tomography (V/Q-SPECT) acquired at baseline with a quantified SPECT (Q-SPECT) repeated at 1 week and 6 months. The Q-defect extent (percentage of total lung volume affected) was measured semiquantitatively. Data collected at baseline were age, gender, body mass index (BMI), history of previous venous thromboembolism (HVTE), Charlson's Comorbidity Score (CcS), plasma troponin-T and D-dimer levels, PE Severity Index, and tricuspid regurgitation jet (TRJ) velocity.

RESULTS:

Forty-six patients (22 men/24 women, mean age 61.7 years (± standard deviation 16.3)) completed the study. At 1 week, 13/46 (28.3 %) and at 6 months 22/46 (47.8%) patients had completely normalized Q-SPECT. Persistence of Q-defects was more frequent in female patients in univariate and multivariate analysis. We found no correlation between the persistence of Q-defects on Q-SPECT and HVTE, BMI, plasma troponin-T, and CcS. However, lower TRJ and younger age were statistically significantly linked to normalization of Q-scans after 6 months of treatment only in univariate analysis. There is no difference in the frequency of recurrent PE in relation to the persistence of Q-defects.

CONCLUSION:

Acute PE patients of female, older age, and higher TRJ in univariate analysis and patients of female in multivariate analysis seem to have a higher risk of persistent Q-defects after 6 months treatment. The presence of residual Q-abnormalities at 6 months was not associated with an increased risk for recurrent PE.

Risk factors for pulmonary embolism in patients preliminarily diagnosed with community-acquired pneumonia: a prospective cohort study

D-dimer levels are increased in patients with acute pulmonary embolism (PE). However, D-dimer levels are also increased in patients with community-acquired pneumonia (CAP). The aim of this prospective cohort study was to examine the incidence and clinical features of patients preliminarily diagnosed with CAP and with increased D-dimer levels, and who finally were diagnosed with PE. Patients diagnosed with CAP and hospitalized in the Respiratory Department of the Tenth People's Hospital Affiliated to Tongji University between May 2011 and May 2013 were enrolled. D-dimer levels were measured routinely after admission. For patients with increased D-dimer levels, those suspected with PE underwent computed tomography pulmonary angiography (CTPA). A total of 2387 patients with CAP was included: 724 (30.3 %) had increased D-dimer levels (median of 0.91 mg/L). CTPA was performed for 139 of the 724 patients (median D-dimer levels of 1.99 mg/L). Among the 139 patients, 80 were diagnosed with PE, and 59 without PE; D-dimer levels were 2.83 and 1.41 mg/L, respectively (p < 0.05). Multivariate analysis showed that age, coronary heart disease, chronic obstructive pulmonary disease (COPD), lower limb varicosity, chest pain, shortness of breath, hemoptysis, fever, and increased levels of troponin I were independent risk factors for PE. Presentation of PE and CAP are similar. Nevertheless, these results indicated that for hospitalized patients with CAP and elevated D-dimer levels, PE should be considered for those >60 years; with CHD, COPD, or lower limb varicosity; with chest pain, shortness of breath, hemoptysis, increased troponin I, or low fever.

Global Anticoagulant Registry in the Field - Venous Thromboembolism (GARFIELD-VTE). Rationale and design

Venous thromboembolism (VTE) is a common disorder associated with significant rates of morbidity and mortality. VTE management aims to reduce mortality, the risks of recurrence, and long-term complications. VTE treatment is evolving with the introduction of non-vitamin K antagonist anticoagulants (NOACs). The Global Anticoagulant Registry in the FIELD - Venous Thromboembolism (GARFIELD-VTE) is a prospective, multicentre, observational study that will enrol 10,000 patients treated for acute VTE from ~500 sites in 28 countries. Identified sites reflect the diversity of care settings, including hospital and outpatient settings. Patients will be managed according to local practices and followed for at least three years. The primary objective is to determine the extent to which VTE treatment varies in the real-world setting and to assess the impact of such variability on clinical and economic outcomes. Evolving patterns of care will be captured using two sequential cohorts. The GARFIELD-VTE registry will provide insights into the evolving global treatment patterns for VTE, both deep-vein thrombosis and pulmonary embolism. By enrolling patients from diverse care settings, the registry will provide information on adherence to national and international guidelines, identify good practice as well as treatment deficiencies, and relate patient outcomes to clinical management. The incidence of death, recurrent VTE, bleeding, post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension will be documented. By capturing information during and after anticoagulation treatment, the registry will not only define aspects of the natural history of VTE, but also its economic and societal impact at a regional and global level.

Edoxaban: A Review in Deep Vein Thrombosis and Pulmonary Embolism

Edoxaban (Lixiana, Savaysa) is an oral, direct factor Xa inhibitor which has recently been approved for use in the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE) [collectively, venous thromboembolism (VTE)] and for the prevention of recurrent VTE. This article reviews the pharmacological properties of edoxaban as well as its tolerability and therapeutic efficacy in the treatment and prevention of recurrent VTE events. As demonstrated in the pivotal Hokusai-VTE phase III trial, once-daily edoxaban after initial treatment with heparin was non-inferior to standard therapy with heparin/warfarin in preventing recurrent VTE events and was associated with a significantly lower risk of clinically relevant bleeding than the traditional therapy. Edoxaban shares the advantages of other direct oral anticoagulants (DOACs) over traditional therapies, including the lack of requirement for routine coagulation monitoring, a rapid onset and offset of action, and few drug-drug interactions. It offers the convenience of once-daily dosing, can be taken without regard to food and allows for a dose reduction in patients with certain clinical features, such as moderate renal impairment or low body weight. In conclusion, edoxaban represents an effective and potentially safer alternative to traditional vitamin K antagonist therapy for the treatment and prevention of recurrent VTE. Its recent approval expands the range of DOAC agents for recurrent VTE, further facilitating treatment individualization.

The safety of fondaparinux sodium for the treatment of venous thromboembolism

INTRODUCTION

Venous thromboembolism (VTE) is a common and potentially fatal disease. Fondaparinux is a synthetic agent able to act on single factors involved in the coagulation network, which could be administered at fixed doses and with a more predictable response.

AREAS COVERED

This review will focus on the efficacy and safety of fondaparinux in the treatment of major VTE (deep vein thrombosis and pulmonary embolism) and in the treatment of superficial vein thrombosis (SVT).

EXPERT OPINION

Results of high quality randomized controlled trials have clearly shown the efficacy and safety of fondaparinux in comparison to conventional treatment in patients with a major VTE. There are limited evidences on the safety and efficacy of different options in patients presenting with SVT. Fondaparinux has been evaluated in a large population of patients presenting with a SVT. Results of this high quality RCT provided the evidence on the efficacy and safety of fondaparinux 2.5 mg s.c./day for 45 days in this setting. Thus, considering the evidence of the literature and thanks to its pharmacokinetic and pharmacodynamic characteristics, fondaparinux represent a valid treatment option for both the acute management of patients with major VTE, and for the treatment of SVT.

Comparison of the Non-VKA Oral Anticoagulants Apixaban, Dabigatran, and Rivaroxaban in the Extended Treatment and Prevention of Venous Thromboembolism: Systematic Review and Network Meta-Analysis

Background

Historically, warfarin or aspirin have been the recommended therapeutic options for the extended treatment (>3 months) of VTE. Data from Phase III randomised controlled trials (RCTs) are now available for non-VKA oral anticoagulants (NOACs) in this indication. The current systematic review and network meta-analysis (NMA) were conducted to compare the efficacy and safety of anticoagulants for the extended treatment of VTE.

Methods

Electronic databases (accessed July 2014 and updated April 2016) were systematically searched to identify RCTs evaluating apixaban, aspirin, dabigatran, edoxaban, rivaroxaban, and warfarin for the extended treatment of VTE. Eligible studies included adults with an objectively confirmed deep vein thrombosis, pulmonary embolism or both. A fixed-effect Bayesian NMA was conducted, and results were presented as relative risks (RRs). Sensitivity analyses examining (i) the dataset employed according to the time frame for outcome assessment (ii) the model used for the NMA were conducted.

Results

Eleven Phase III RCTs (examining apixaban, aspirin, dabigatran, rivaroxaban, warfarin and placebo) were included. The risk of the composite efficacy outcome (VTE and VTE-related death) was statistically significantly lower with the NOACs and warfarin INR 2.0–3.0 compared with aspirin, with no significant differences between the NOACs. Treatment with apixaban (RR 0.23, 95% CrI 0.10, 0.55) or dabigatran (RR 0.55, 95% Crl 0.43, 0.71) was associated with a statistically significantly reduced risk of ‘major or clinically relevant non-major bleed’ compared with warfarin INR 2.0–3.0. Apixaban also showed a significantly reduced risk compared with dabigatran (RR 0.42, 95% Crl 0.18, 0.97) and rivaroxaban (RR 0.23, 95% Crl 0.09, 0.59). Sensitivity analyses indicate that results were dependent on the dataset, but not on the type of NMA model employed.

Conclusions

Results from the NMA indicate that NOACs are an effective treatment for prevention of VTE or VTE-related death) in the extended treatment setting. However, bleeding risk differs between potential treatments, with apixaban reporting the most favourable profile compared with other NOACs, warfarin INR 2.0–3.0, and aspirin.

Direct Oral Anticoagulants for the Management of Thromboembolic Disorders

Anticoagulation therapy is central to the management of thromboembolic disorders, and the use of direct oral anticoagulants offers several advantages over standard therapy with parenteral heparins and vitamin K antagonists. In phase III clinical trials, the direct oral anticoagulants (given once or twice daily) all demonstrated favorable benefit–risk profiles compared with conventional standard therapy for the treatment and secondary prevention of venous thromboembolism and for stroke prevention in patients with nonvalvular atrial fibrillation. In clinical practice, many factors may influence overall clinical outcomes in patients receiving anticoagulant therapy, including adherence and persistence to the prescribed therapy, which becomes particularly important during long-term therapy. When choosing an anticoagulant for an individual patient, the pharmacological and clinical profile of the anticoagulant, its dosing regimen, and the patient’s clinical characteristics (eg, renal function and comorbidities) and preferences should be considered. This review examines the rationale for and clinical evidence of the selected dosing regimens of the direct oral anticoagulants for the treatment of venous thromboembolism and stroke prevention in nonvalvular atrial fibrillation. The potential influence of dosing strategies (eg, once- or twice-daily dosing) and other factors on patient adherence and therapy persistence are also discussed.

Management of Venous Thromboembolisms: Part I. The Consensus for Deep Vein Thrombosis

Deep vein thrombosis (DVT) is a potentially catastrophic condition because thrombosis, left untreated, can result in detrimental pulmonary embolism. Yet in the absence of thrombosis, anticoagulation increases the risk of bleeding. In the existing literature, knowledge about the epidemiology of DVT is primarily based on investigations among Caucasian populations. There has been little information available about the epidemiology of DVT in Taiwan, and it is generally believed that DVT is less common in Asian patients than in Caucasian patients. However, DVT is a multifactorial disease that represents the interaction between genetic and environmental factors, and the majority of patients with incident DVT have either inherited thrombophilia or acquired risk factors. Furthermore, DVT is often overlooked. Although symptomatic DVT commonly presents with lower extremity pain, swelling and tenderness, diagnosing DVT is a clinical challenge for physicians. Such a diagnosis of DVT requires a timely systematic assessment, including the use of the Wells score and a D-dimer test to exclude low-risk patients, and imaging modalities to confirm DVT. Compression ultrasound with high sensitivity and specificity is the front-line imaging modality in the diagnostic process for patients with suspected DVT in addition to conventional invasive contrast venography. Most patients require anticoagulation therapy, which typically consists of parenteral heparin bridged to a vitamin K antagonist, with variable duration. The development of non-vitamin K oral anticoagulants has revolutionized the landscape of venous thromboembolism treatment, with 4 agents available,including rivaroxaban, dabigatran, apixaban, and edoxaban. Presently, all 4 drugs have finished their large phase III clinical trial programs and come to the clinical uses in North America and Europe. It is encouraging to note that the published data to date regarding Asian patients indicates that such new therapies are safe and efficacious. Ultimately, our efforts to improve outcomes in patients with DVT rely on the awareness in the scientific and medical community regarding the importance of DVT.

KEY WORDS

Combination therapy; Hypertension; α1-blocker.

Systematic review of the complications following isolated calf deep vein thrombosis

Background

A large number of studies have examined the potential complications of calf deep vein thrombosis (DVT). There is no consensus on when or how to treat patients to prevent these complications. This systematic review assessed the rate of proximal propagation, pulmonary embolism, major bleeding and recurrence in patients with isolated calf DVT.

Methods

Database searches of MEDLINE, the Cochrane Library, Scopus, CINAHL and Web of Science were undertaken along with extensive cross-referencing. Two independent reviewers screened the papers using stringent inclusion and exclusion criteria. Included studies were graded on six methodological standards. Data on propagation, pulmonary embolism, recurrence and major bleeding were abstracted.

Results

A total of 4261 papers were found; 15 met the inclusion criteria, including five randomized clinical trials and ten prospective cohort studies. The propagation rate to the popliteal vein or above was around 9 per cent and the rate of pulmonary embolism was close to 1·5 per cent. No studies found anticoagulant therapy to reduce the rate of adverse outcomes.

Conclusion

The literature on calf DVT is heterogeneous, limiting conclusions from data analysis. Adverse outcomes are infrequent and studies do not suggest that they are reduced by anticoagulation.

Recurrent hospitalization and healthcare resource use among patients with deep vein thrombosis and pulmonary embolism: findings from a multi-payer analysis

The objective of this study was to assess deep vein thrombosis and pulmonary embolism (DVT/PE) recurrence rates and resource utilization among patients with an initial DVT or PE event across multiple payer perspectives. Retrospective analyses were performed using a software tool that analyzes health plan claims to evaluate treatment patterns and resource utilization for various cardiovascular conditions. Six databases were analyzed from three payer perspectives (Commercial, Medicare, and Medicaid). Patients were ≥18 years old with a primary diagnosis of DVT or PE associated with an inpatient and/or emergency room claim, had received an antithrombotic within 7 days before or 14 days after index, and had no diagnosis of atrial fibrillation during follow-up. Outcomes were assessed over a 1 year period following index. More PE patients were hospitalized for their index event than DVT patients (42–59 % DVT and 69–86 % PE) and had longer mean length of stay (2.35–2.95 days DVT and 3.26–3.76 days PE). Recurrent event rates among PE patients (12–32 %) were higher than those for DVT patients (6–16 %) across all payers. The highest rate of recurrence was observed among the Medicaid population [23 % overall (VTE); 16 % DVT; 32 % PE]. All-cause hospitalization in the year following their VTE episode occurred in 23–67 % DVT patients and 30–68 % PE patients. Medicaid had the highest proportion of patients with hospitalizations and ER visits. Recurrent VTE events and all-cause hospitalizations are relatively common, especially for patients who had a PE, and among those in the Medicaid payer population.

The epidemiology of venous thromboembolism

Venous thromboembolism (VTE) is categorized by the U.S. Surgeon General as a major public health problem. VTE is relatively common and associated with reduced survival and substantial health-care costs, and recurs frequently. VTE is a complex (multifactorial) disease, involving interactions between acquired or inherited predispositions to thrombosis and VTE risk factors, including increasing patient age and obesity, hospitalization for surgery or acute illness, nursing-home confinement, active cancer, trauma or fracture, immobility or leg paresis, superficial vein thrombosis, and, in women, pregnancy and puerperium, oral contraception, and hormone therapy. Although independent VTE risk factors and predictors of VTE recurrence have been identified, and effective primary and secondary prophylaxis is available, the occurrence of VTE seems to be relatively constant, or even increasing.

Comparison of the Novel Oral Anticoagulants Apixaban, Dabigatran, Edoxaban, and Rivaroxaban in the Initial and Long-Term Treatment and Prevention of Venous Thromboembolism: Systematic Review and Network Meta-Analysis

Background

Anticoagulation with low molecular weight heparin and vitamin K antagonists is the current standard of care (SOC) for venous thromboembolism (VTE) treatment and prevention. Although novel oral anti-coagulants (NOACs) have been compared with SOC in this indication, no head-to-head randomised controlled trials (RCTs) have directly compared NOACs. A systematic review and network meta-analysis (NMA) were conducted to compare the efficacy and safety of NOACs for the initial and long-term treatment of VTE.

Methods

Electronic databases (accessed July 2014) were systematically searched to identify RCTs evaluating apixaban, dabigatran, edoxaban, and rivaroxaban versus SOC. Eligible patients included adults with an objectively confirmed deep vein thrombosis (DVT), pulmonary embolism (PE) or both. A fixed-effect Bayesian NMA was conducted for outcomes of interest, and results were presented as relative risks (RR) and 95% credible intervals (Crl).

Results

Six Phase III RCTs met criteria for inclusion: apixaban (one RCT; n = 5,395); rivaroxaban (two RCTs; n = 3,423/4,832); dabigatran (two RCTs; n = 2,539/2,568); edoxaban (one RCT; n = 8,240). There were no statistically significant differences between the NOACs with regard to the risk of ‘VTE and VTE-related death. Apixaban treatment was associated with the most favourable safety profile of the NOACs, showing a statistically significantly reduced risk of ‘major or clinically relevant non-major (CRNM) bleed’ compared with rivaroxaban (0.47 [0.36, 0.61]), dabigatran (0.69 [0.51, 0.94]), and edoxaban (0.54 [0.41, 0.69]). Dabigatran was also associated with a significantly lower risk of ‘major or CRNM bleed’ compared with rivaroxaban (0.68 [0.53, 0.87]) and edoxaban (0.77 [0.60, 0.99]).

Conclusions

Indirect comparisons showed statistically similar reductions in the risk of ‘VTE or VTE-related death for all NOACs. In contrast, reductions in ‘major or CRNM bleed’ for initial/long-term treatment were significantly better with apixaban compared with all other NOACs, and with dabigatran compared with rivaroxaban and edoxaban. Results from the current analysis indicate that the NOACs offer clinical benefit over conventional therapy while highlighting relative differences in their bleeding profile.

Role of family history of venous thromboembolism and thrombophilia as predictors of recurrence: a prospective follow-up study

BACKGROUND

Several studies have shown that the family history of venous thromboembolism (FHVTE) is a predictor of first venous thromboembolism (VTE). However its role in recurrent VTE is still controversial.

OBJECTIVES

To investigate whether the presence of FHVTE is a risk factor for VTE recurrence in patients from a well-characterized Malmö thrombophilia study.

METHODS

VTE patients from the Malmö Thrombophilia Study were followed from discontinuation of warfarin treatment until diagnosis of VTE recurrence or to the end of the study (maximum follow-up 9.8 years).

RESULTS

There were 127 events of VTE recurrence (12.2%) registered during the follow-up. Multivariate Cox regression analysis in patients with unprovoked first VTE showed that FHVTE was associated with higher risk of VTE recurrence (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.2-2.9) compared with patients with no FHVTE. Stratification of data according to thrombophilia status of patients showed that compared with the reference group (no FHVTE or thrombophilia), thrombophilia together with FHVTE was associated with a higher risk of VTE recurrence (HR 3.2, 95% CI 1.8-5.9) than thrombophilia alone (HR 1.8, 95% CI 1.02-3.2) independent of DVT location and duration of warfarin treatment. FHVTE was mainly an important risk factor of VTE recurrence in women (HR 3.1, 95% CI 1.6-5.8) but not in men (HR 1.1, 95% CI 0.6-2.2).

CONCLUSION

Our results show that FHVTE is a risk factor for VTE recurrence in patients who had unprovoked first VTE. Furthermore, presence of FHVTE may be an additional risk factor of VTE recurrence in thrombophilia-positive patients.

Patterns and Predictors of Use of Anticoagulants for the Treatment of Venous Thromboembolism Following Approval of Rivaroxaban

BACKGROUND

Few studies have identified patterns and predictors of use of direct oral anticoagulants for venous thromboembolism (VTE).

OBJECTIVE

To describe the use of anticoagulants and assess predictors associated with the prescription of rivaroxaban over vitamin K antagonist (VKA) for the subsequent treatment of VTE.

METHODS

This cross-sectional study was built with all consecutive patients newly diagnosed with acute VTE admitted between February 18, 2013, and September 18, 2013, in an academic tertiary care center in Quebec, Canada. Patient characteristics and VTE treatments were described. Univariate analyses and a multiple forward stepwise logistic regression were performed to assess predictors of rivaroxaban use over VKA for the subsequent treatment of VTE.

RESULTS

The study included 256 patients, 36.7% with a diagnosis of deep vein thrombosis (DVT) and 63.3% with pulmonary embolism (PE). Mean age was 63.1 years, and 28.1% of patients had cancer-associated VTE. Overall, rivaroxaban was prescribed in 1.6% of patients for the initial treatment and in nearly 20% of patients for the subsequent treatment of VTE. Low-molecular-weight heparin and VKA were mostly prescribed. Independent predictors associated with the prescription of rivaroxaban over VKA were as follows: age < 65 years (OR: 2.86, 95% CI 1.29-6.37), a diagnosis of DVT versus PE (OR 2.54, 95% CI 1.20-5.40), and an emergency department visit rather than a hospitalization (OR 2.24, 95% CI 1.06-4.71).

CONCLUSION

Several months following its availability, rivaroxaban was rarely prescribed for acute VTE disease. It also appears to be prescribed in different patient populations than VKA.

BRCA2 gene mutations and coagulation-associated biomarkers

Thromboembolic events are the second cause of death in cancer patients, although the mechanisms underlying this increased thromboembolic risk remain unclear. The aims of this study were to examine whether BRCA2 gene mutations may modify the circulating levels of thrombocoagulation biomarkers and whether breast cancer development may influence changes in such circulating biomarkers. The study was performed in 25 women with mutations in the BRCA2 gene (n=12 breast cancer, n=13 breast cancer-free) and in 13 BRCA2 non-mutant controls. Results revealed that plasma levels of fibrinogen gamma chain isotypes 2 and 3, haptoglobin isotypes 4 and 5, serotransferrin isotypes 3 and 4 and convertase C3/C5 isotypes 4 and 5 were significantly higher in BRCA2 mutation carriers compared to controls. However, plasma levels of vitamin D binding protein isotype 1 and alpha1-antitrypsin isotypes 2, 3 and 4 were significantly decreased in BRCA2 mutation carriers compared to controls. Plasma expression of PF4 and P-selectin was significantly higher in BRCA2 mutations carriers than in controls. BRCA2 truncated mutations conserving a binding region for RAD51 were associated with increased plasma levels of alpha1-antitrypsin isotypes 3 and 4 with respect to women showing BRCA2 mutations that loss the binding RD51 region to BRCA2. Only plasma levels of vitamin D binding protein isotypes 1 and 3 were significantly reduced and alpha 1-antitrypsin isotype 1 was increased in cancer-free BRCA2 mutation carriers compared to BRCA2 mutation carriers with breast cancer. The presence of BRCA2 mutations is associated with increased plasma levels of thrombo-coagulating-related proteins, which are independent to breast cancer development.

Should lifelong anticoagulation for unprovoked venous thromboembolism be revisited?

Venous thromboembolism [VTE] is a common medical condition that has significant morbidity and mortality. Although stringent guidelines recommend lifelong anticoagulation for patients with unprovoked VTE, the optimal management strategy for their long term treatment remains controversial.

Whereas in cancer-associated VTE and second unprovoked VTE lifelong anticoagulation is universally accepted, a careful analysis of the benefit vs. risk of long-term anticoagulation following a first unprovoked VTE should be considered as case fatality rates [CFR] from VTE appear more pronounced in the first few months. The CFR from major bleeding remains constant throughout therapy. Therefore, the risk of bleeding may be underestimated over longer treatment periods relative to the morbidity of recurrent VTE which appears to peak in the first year. The current review highlights the balance between the recurrence risk and bleeding risks in the era of direct oral anticoagulants.

Vitamin K antagonists have been the standard of care for over 50 years bearing significant bleeding risks. The new oral anticoagulants [NOACs] have shown similar efficacy and perhaps a questionable improved safety profile when compared to warfarin.

Aspirin has historically not been a useful agent in the management of VTE. However, two recent trials [WARFASA and ASPIRE] showed a likely 20-30 % risk reduction when compared to placebo for recurrent VTE after initial anticoagulation. The risk of major hemorrhage was low in both trials.

With the emergence of NOACs and the increased utility of aspirin, there are multiple therapeutic options for long term management for VTE. Given comparable efficacy and improved safety of NOACs and aspirin, the risk benefit of anticoagulation is improving.

A risk stratification model may help identifying patients at high risk for recurrence necessitating a lifelong anticoagulation. This cohort should be separated from a low risk group that may benefit from clinical observation, aspirin or NOACs.

Prospective clinical trials are needed to support these clinical observations.

History of deep vein thrombosis is a discriminator for concomitant atrial fibrillation in pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is the consequence of deep vein thrombosis (DVT) in 70% of all cases. Although, PE and DVT are commonly related to risk factors of Virchow's triad, both entities are linked to cardiovascular risk factors, but risk factors seem differently important in both entities.

OBJECTIVES

We aimed to investigate clinical profile and outcome of patients with PE history stratified by concomitant DVT.

PATIENTS/METHODS

Data from the observational multi-center thrombEVAL-study were analyzed.

RESULTS

The sample (N=2,318) comprised 295 PE patients, of whom 69.2% (N=204) had DVT. Individuals without DVT were older and had higher prevalence of concomitant atrial fibrillation (AF), chronic lung diseases, coronary artery disease, heart failure and hypertension. Multivariable regression revealed an independent association of AF (Odds Ratio (OR) 3.17, 95% CI 1.63-6.18, P<0.001) and coronary artery disease (OR 2.31, 95% CI 1.15-4.66, P=0.019) with PE without DVT. There was higher frequency of permanent AF in individuals without DVT, whereas paroxysmal AF was more prevalent in individuals with DVT. All AF subtypes were independently associated with PE without DVT with increasing ORs from paroxysmal to permanent AF. PE patients with and without DVT did not differ in survival (P=0.32) and cost-relevant clinical outcome (P=0.26) during follow-up. AF in PE patients was associated with cost-relevant clinical outcome (Hazard Ratio (HR) 1.78, 95% CI 1.03-3.09, P=0.040), but no significant difference in survival (HR 0.93, 95% CI 0.35-2.50, P=0.88) was observed.

CONCLUSIONS

History of DVT is a significant discriminator for clinical profile of PE patients. Individuals without DVT had more often cardiac and pulmonary disease with strongest association with AF. Data advocate a potential link between AF and PE.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov, Unique identifier NCT01809015.

New oral anticoagulants for the treatment of venous thromboembolism: understanding differences and similarities

Venous thromboembolism (VTE) is a major cause of morbidity, mortality, and healthcare expenditure. In the United States, approximately 0.1 % of the population experiences an initial VTE event each year. Anticoagulation therapy is the cornerstone of acute VTE treatment and for prevention of recurrent VTE events. Conventional anticoagulants, including heparin, low-molecular-weight heparins, fondaparinux, and vitamin K antagonists are widely used but have limitations. Newer oral anticoagulant agents, including direct thrombin inhibitors (e.g., dabigatran etexilate) and direct factor Xa inhibitors (e.g., rivaroxaban, apixaban, and edoxaban) have been developed to attempt to overcome some of the limitations of conventional anticoagulant therapy. These new oral agents have been evaluated for safety and efficacy in large, randomized clinical trials in the treatment and secondary prevention of VTE with results that are comparable to conventional therapy. Dabigatran, rivaroxaban, apixaban, and edoxaban are important new treatment options for patients with VTE. In this review, we compare these new agents and their associated clinical trials in VTE treatment.

Epidemiology of venous thromboembolism

Thrombosis can affect any venous circulation. Venous thromboembolism (VTE) includes deep-vein thrombosis of the leg or pelvis, and its complication, pulmonary embolism. VTE is a fairly common disease, particularly in older age, and is associated with reduced survival, substantial health-care costs, and a high rate of recurrence. VTE is a complex (multifactorial) disease, involving interactions between acquired or inherited predispositions to thrombosis and various risk factors. Major risk factors for incident VTE include hospitalization for surgery or acute illness, active cancer, neurological disease with leg paresis, nursing-home confinement, trauma or fracture, superficial vein thrombosis, and-in women-pregnancy and puerperium, oral contraception, and hormone therapy. Although independent risk factors for incident VTE and predictors of VTE recurrence have been identified, and effective primary and secondary prophylaxis is available, the occurrence of VTE seems to be fairly constant, or even increasing.

The economic implications of switching to rivaroxaban from enoxaparin plus vitamin K antagonist in the treatment of venous thromboembolism

OBJECTIVE

Venous thromboembolism (VTE) impacts ∼900,000 individuals annually in the US, causing up to 100,000 deaths. Patients experiencing VTE have heightened risk of recurrence. Initial parenteral anti-coagulation is standard therapy for acute VTE followed by ≥3 months of warfarin, which introduces the risk of major bleeding. Balancing increased risks of bleeding and recurrent VTE remains challenging. Recent clinical trials suggest that rivaroxaban, an oral direct inhibitor of factor Xa, provides an effective, safe, simplified approach to treatment. This study considers the economic implications of these data.

METHODS

This study modeled inpatient, acute, and 1-year VTE costs for a hypothetical commercial plan with 1 million members. At baseline, all VTE patients receive standard therapy. Alternatively, 25% are instead treated with rivaroxaban. Model inputs are trial- and literature-based.

RESULTS

Standard therapy for VTE consumes 9474 inpatient days ($31.6 million). Added to that is treatment for 74 recurrences ($1.4 million); major and non-major bleed events ($1 million); and direct costs of anti-coagulation ($5.3 million). Alternatively, a 25% shift to oral anti-coagulation with rivaroxaban reduces inpatient days (by 5%); associated acute-care costs (by 2%); recurrences and costs (by 6%). Four major bleeding events are prevented, at the cost of one additional non-major bleeding event, which, taken together, reduce net utilization by 9%. Direct costs of anti-coagulation increase by 5%.

CONCLUSION

The reduction in inpatient utilization, recurrences, and major bleeding resulting from a 25% shift from standard therapy to rivaroxaban following acute VTE would conserve ∼$860,475 for every 1 million commercial health plan enrollees.

A practical approach to the use of low molecular weight heparins in VTE treatment and prophylaxis in children and newborns

Low-molecular weight heparins are currently the most commonly used anticoagulants in children and newborns. However, since thrombotic complications rarely occur outside large children's hospitals, physicians often encounter some practical problems in managing these treatments when a pediatric thrombosis specialist is not available. The drug of choice is enoxaparin, due to its favorable FXa/FIIa ratio and the availability of pharmacokinetic and pharmacodynamic data. The treatment of acute thrombosis should be started with two daily injections but when compliance is an issue, a single daily administration schedule could be chosen for secondary prophylaxis ensuring careful measurement of the post 24-hour anti-FXa activity. Furthermore, a subcutaneous device may be a useful tool and a topical dermal anesthetic could be effective in controlling pain without affecting anti-FXa levels. In neonate and toddlers, where mini doses are frequently needed, the dead space of syringes and needles could represent an issue and therefore the use of insulin syringes without dead space is advisable, while a dilution of the drug is useful with other syringes. This article derives from a nonsystematic review of the available literature, with special attention to recent international guidelines and expert recommendations, combined to authors' clinical practice in large tertiary pediatric hospitals and will provide concise and practical information for the use of low-molecular weight heparin in childhood and infancy in a sort of "answering frequently asked questions."

The potential of target-specific oral anticoagulants for the acute and long-term treatment of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) comprises both deep vein thrombosis and pulmonary embolism. VTE is a leading cause of morbidity and mortality worldwide and its increasing incidence and prevalence are a major health concern. The primary medical objective during the acute phase of VTE treatment is to prevent thrombus extension and embolization. Extended treatment aims to prevent or minimize long-term complications, such as recurrent VTE, post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension.

SCOPE

Anticoagulant therapy has been the mainstay of treatment for VTE and traditionally involves initial therapy with heparin, overlapping with and followed by a vitamin K antagonist. Although effective, standard heparin/vitamin K antagonist therapy has several limitations that can be overcome by more recently developed target-specific oral anticoagulants (TSOACs). These agents have predictable pharmacokinetics, a rapid onset of action and few drug-drug or drug-food interactions. Furthermore, TSOACs offer convenient anticoagulation without the need for routine coagulation monitoring and dose adjustment.

FINDINGS

The efficacy and safety data from phase III clinical trials support the use of TSOACs for VTE treatment, including in special patient populations. Risk-stratification tools and strategies have been developed to assist physicians in managing anticoagulation treatment.

CONCLUSIONS

Rivaroxaban is the first TSOAC to gain widespread approval for the treatment of acute deep vein thrombosis and pulmonary embolism and the long-term prevention of recurrent VTE as monotherapy. Dabigatran has also been approved for this indication recently. TSOACs, especially as monotherapy, represent a paradigm shift in clinical practice for the management of patients with VTE.

Pulmonary hypertension in systemic lupus erythematosus: pulmonary thromboembolism is the leading cause

BACKGROUND

Pulmonary hypertension (PH) is a life-threatening complication of systemic lupus erythematosus (SLE). Pulmonary hypertension in SLE has a variety of causes. Diagnosing early and defining the cause of PH accurately can provide better clinical outcome in SLE. We investigated the causes and characteristics of PH in patients with SLE.

METHODS

One hundred twenty-one patients with SLE who had a visit in a 6-month period were assessed retrospectively. Patients who ever had a systolic pulmonary arterial pressure of 40 mm Hg or greater by Doppler echocardiography were considered to have PH.

RESULTS

Among 122 patients, 65 had echocardiography for some reason, and 10 (8.2%) were diagnosed as having PH by echocardiographic examination. This number reduced to 9 (7.4%) when we excluded the patient with normal pulmonary artery pressure at right heart catheterization. Causes of PH were as follows: thromboembolic events in 4 patients (44.4%) (2 of them had chronic thromboembolic PH), left-sided heart disease in 2 patients (22.2%), pulmonary arterial hypertension in 1 patient (11.1%), high cardiac output state in 1 patient (11.1%), and transient elevation of systolic pulmonary artery pressure in 1 patient (11.1%) who had a history of venous thromboembolism. Venous thromboembolic disease was significantly higher in patients with SLE with PH in comparison to patients with SLE without PH (7 patients [6.3%] vs 5 patients [50.0%]; P = 0.001). All patients improved clinically during their short-term follow-up.

CONCLUSIONS

Patients with SLE are at increased risk for PH. This study highlights the complexity of the differential diagnosis of PH in patients with SLE once again and emphasizes the importance of pulmonary thromboembolism as a cause of PH. One should investigate patients with SLE with unexplained symptoms and/or signs related to PH for possible treatable causes.

The use of oral anticoagulants for the treatment of venous thromboembolic events in an ED

Venous thromboembolism (VTE) is a disease spectrum that ranges from deep vein thrombosis (DVT) to pulmonary embolism (PE). Rapid diagnosis and treatment of VTE by emergency care providers are critical for decreasing patient mortality, morbidity, and the incidence of recurrent events. Recent American College of Chest Physicians guidelines recommend initial treatment with unfractionated heparin, low-molecular weight heparin, or fondaparinux overlapped with warfarin for a minimum of 5 days for the treatment of VTE in most cases. Warfarin monotherapy is thereafter continued for 3, 6, or 12 months. These guidelines were published before the approval of target-specific oral anticoagulants (TSOACs), and they have yet to be updated to reflect these new treatment options. For some patients, TSOACs, which act by directly inhibiting factor IIa or factor Xa, may provide safer, more convenient alternatives to warfarin. Their advantages include ease of use, reduced monitoring requirements, and lower bleeding risk than traditional therapy. Additionally, clinical trials have established noninferiority of TSOACs to warfarin for the prevention of recurrent VTE. These trials have demonstrated that TSOACs exhibit similar or lower bleeding rates, particularly intracranial bleeding rates compared with warfarin. Anticoagulation therapy with TSOACs may allow early discharge or outpatient management options for low-risk patients with DVT and PE. This review addresses the importance of early diagnosis and treatment of VTE, outcomes of VTE risk assessment, key efficacy and safety data from phase 3 clinical trials for the various TSOACs for the treatment of DVT and PE, and the corresponding considerations for clinical practice.

Weekly risk of venous thromboembolism recurrence in patients receiving oral anticoagulants

BACKGROUND

Data is currently lacking in evaluating the weekly rates of recurrent venous thromboembolism (VTE) among patients receiving anticoagulants.

OBJECTIVE

To quantify the risk of VTE recurrence during the first 12 weeks after an index VTE event.

METHODS

Healthcare claims from Truven Health Analytics MarketScan database from January 2007 to June 2012 were analyzed. Adult patients with ≥1 diagnosis of VTE, ≥1 anticoagulant prescription dispensed within 7 days of the index VTE hospitalization discharge or outpatient/emergency room (ER) visit (index date), and a proportion of days covered ≥0.7 on the anticoagulant therapy during the 12 weeks post-discharge were included. The weekly risk of VTE recurrence was evaluated with the hazard function using the life-table method.

RESULTS

A total of 105,682 patients with a VTE were included. Mean age was 59 years and 49% were female. The risk of VTE recurrence was at its highest during the first and second weeks, at 0.78% and 0.83%, respectively. The risk remained high during Weeks 3, 4, and 5 with risks of VTE recurrence of 0.63%, 0.52%, and 0.39%, respectively. The risk of VTE recurrence stabilized around Week 7, with risks of 0.26%, 0.22%, 0.20%, 0.25%, 0.23%, and 0.23% for Weeks 7, 8, 9, 10, 11 and 12, respectively.

LIMITATIONS

Claims data may have contained inaccuracies. During hospitalizations it was not possible to assess anticoagulant use or a VTE recurrence occurring in the same hospitalization as the index VTE event.

CONCLUSION

This analysis suggests that the risk of VTE recurrence remains high in the early weeks after an index VTE among patients receiving anticoagulants.

Prior myocardial infarction and presence of upper gastrointestinal conditions among patients with venous thromboembolism: prevalence, associated comorbidities and burden

WHAT IS KNOWN AND OBJECTIVES

Venous thromboembolism (VTE), comprising deep vein thrombosis (DVT) and pulmonary embolism (PE), is a serious, life-threatening condition that often complicates treatment of individuals who are already ill and increases in risk with age. The comorbidity burden of VTE can complicate treatment; therefore, treatment should be influenced by the presence of comorbidities (Kearon 2012). The prevalence of common conditions in the VTE population is, therefore, an important subject of research. Prevalence of two common comorbid burdens, prior myocardial infarction (MI) and upper gastrointestinal (GI) conditions, was studied among survey respondents who reported DVT or PE.

METHODS

Responses to the 2010 wave of the National Health and Wellness Survey (NHWS), a self-administered, internet-based questionnaire from a nationwide, demographically representative sample of adults, were evaluated.

RESULTS AND DISCUSSION

Among the 814 participants reporting a history of VTE, 9·7% (n = 60) of the DVT subpopulation and 13·2% (n = 39) of the PE subpopulation also reported prior MI. In respondents with prior MI, cardiovascular, urological, and pain comorbidities were each reported as additional comorbidities by at least two thirds of respondents in both the PE and DVT subpopulations, with cardiovascular and urological conditions reported significantly (P < 0·05) more often than among respondents with no prior MI. Among the respondents reporting VTE, 48·9% (n = 302) of the subpopulation reporting DVT and 52·2% (n = 154) of those reporting PE also reported upper GI comorbidities. Cardiovascular and pain conditions in the respondents reporting upper GI comorbidities were each reported by more than three quarters of VTE patients in both the DVT and PE subpopulations and were significantly more common (P < 0·05) than among their counterparts without upper GI comorbidities.

WHAT IS NEW AND CONCLUSION

The results of the NHWS indicate that VTE patients who have either of two common comorbid burdens, prior MI and concomitant upper GI conditions, also showed high levels of additional, concurrent comorbidities and generally poor health status. Clinicians must be aware of the total comorbidity profile of their patients who have experienced VTE in order to best manage them and prescribe appropriate therapy.

Family history of venous thromboembolism (VTE) and risk of recurrent hospitalization for VTE: a nationwide family study in Sweden

BACKGROUND

Data concerning the importance of a family history of venous thromboembolism (VTE) for the risk of recurrent VTE are sparse. The aim of this nationwide study was to determine whether a family history of VTE is a risk factor for recurrent hospitalization for unprovoked VTE (deep vein thrombosis of the lower extremities or pulmonary embolism).

METHODS

We linked Multigeneration Register data on individuals aged 0-77 years to the Swedish nationwide Hospital Discharge Register data for the period 1987-2009 to compare the risk of hospitalization for unprovoked recurrent VTE among individuals with and without a parental or sibling history of VTE. We calculated hazard ratios (HRs) to determine the familial HR for recurrent hospitalization for VTE.

RESULTS AND CONCLUSIONS

The risk of recurrent VTE hospitalization was 1.20 (95% confidence interval [CI] 1.10-1.32) for individuals with affected parents, and 1.30 (95% CI 1.14-1.49) for those with affected siblings. The risk of recurrent VTE hospitalization in individuals with two affected parents was 1.92 (95% CI 1.44-2.58). There was an interaction between age at diagnosis of VTE and a family history of VTE, with a family history having a stronger effect on VTE risk in younger patients. We conclude that a family history of VTE is a modest risk factor for recurrent VTE hospitalization in Sweden.

Prevalence of thrombophilia according to age at the first manifestation of venous thromboembolism: results from the MAISTHRO registry

Thrombophilia is a well-established risk factor for a venous thromboembolic event (VTE), and it has been proposed that hereditary thrombophilia may substantially contribute to the development of VTE in young patients. We aimed to analyse the prevalence of thrombophilia with special regard to the age of VTE manifestation. The study cohort consisted of 1490 patients (58% females) with a median age 43 years at the time of their first VTE. At least one thrombophilic disorder was identified in 50·1% of patients. The probability of detecting a hereditary thrombophilia declined significantly with advancing age (from 49·3% in patients aged 20 years and younger to 21·9% in patients over the age of 70 years; P < 0·001). This may be primarily attributed to the decreasing frequencies of the F5 R506Q (factor V Leiden) mutation and deficiencies of protein C or protein S with older age at the time of the initial VTE event. Moreover, thrombophilia was more prevalent in unprovoked compared with risk-associated VTE (57·7% vs. 47·7%; P = 0·001). The decline in the prevalence of hereditary thrombophilia with older ages supports the use of a selected thrombophilia screening strategy dependent on age and the presence or absence of additional VTE risk factors.

New anticoagulants for treatment of venous thromboembolism

Venous thromboembolism (VTE) is a major cause of morbidity and mortality and anticoagulation is the cornerstone of treatment. Although effective, traditional anticoagulants (i.e., heparins and vitamin K antagonists) have significant limitations and there are several unmet needs. Therefore, new drugs have been developed, including direct factor Xa inhibitors (e.g., rivaroxaban, apixaban and edoxaban) and thrombin inhibitors (e.g., dabigatran etexilate). The characteristics of these agents and the main results of published clinical studies dealing with VTE treatment are critically summarized in this article.