Duration of anticoagulation after initial idiopathic venous thrombosis--the swinging pendulum: risk assessment to predict recurrence

The influence of thrombophilia on the long-term survival of patients with a history of venous thromboembolism

Data on the long-term survival following venous thromboembolism (VTE) are rare,and the influence of thrombophilia has not been evaluated thus far. Our aim was to assess thrombophilia-parameters as predictors for long-term survival of patients with VTE. Overall, 1,905 outpatients (99 with antithrombin-, protein C or protein S deficiency, 517 with factor V Leiden, 381 with elevated factor VIII and 160 with elevated homocysteine levels, of these 202 had a combination and 961 had none of these risk factors) were included in the study between September 1, 1994 and December 31, 2007. Retrospective survival analysis showed that a total of 78 patients (4.1%) had died during the analysis period, among those four of definite or possible pulmonary embolism and four of bleeding. In multivariable analysis including age and sex an association with increased mortality was found for hyperhomocysteinemia (hazard ratio 2.0 [1.1.-3.5]) whereas this was not the case for all other investigated parameters. We conclude that the classical hereditary thrombophilia risk factors did not have an impact on the long-term survival of patients with a history of VTE. Thus our study supports the current concept that thrombophilia should not be a determinant for decision on long term anticoagulation. However, hyperhomocysteinaemia, known as a risk factor for recurrent VTE and arterial disease, might impact survival.

Do novel oral anticoagulants do better than standard therapy in the treatment of deep vein thrombosis?

The focus of DVT treatment is the prevention of recurrence and thrombus migration by treatment with anticoagulants. The aim is to improve outcomes by reducing clot burden and by preventing thrombus propagation, in order to prevent PE and the development of long-term complication. Actually, initial therapy is parenteral anticoagulation, mainly with low molecular weight heparin followed by a vitamin K antagonist (VKA) for triggered and idiopathic DVT. The long term treatment suggestion with a VKA is for sure the most challenging therapeutic scenario, showing all the disadvantages of VKA especially in the onset phase when therapeutic levels of VKA are difficult to achieve. The difference between VKAs and NOACs is the fact, that NOACs target a specific factor in the coagulation cascade. At time now two pathways have been chosen for treatment options, the direct inhibition of active sites of thrombin and factor Xa. Routine monitoring is not required and the drugs can be administered in fixed doses, which should increase patient adherence to long term treatment. At time now, four novel anticoagulants are called to be options for DVT treatment. Rivaroxaban, apixaban and edoxaban are direct FXa inhibitors, whereas dabigtran etexilate is a direct thrombin inhibitor.

A survey of the clinical course and management of Japanese patients deficient in natural anticoagulants

Few data are available on the clinical course of Japanese patients deficient in natural anticoagulants (antithrombin (AT), protein C, and protein S). We conducted a nationwide survey to reveal the clinical course of these patients. Questionnaires were sent to 321 council members of the Japanese Society on Thrombosis and Hemostasis, Japanese Society for Vascular Surgery, and Japanese Society of Phlebology. A total of 103 responses were obtained and data of 183 patients were collected. Of 183 patients, 142 (78%) experienced at least one episode of venous thromboembolism (VTE). The first VTE occurred before the age of 40 years in 71 patients (45%). Venous thromboembolism recurred in 15 (39%) patients with AT deficiency and 19 (18%) patients with other deficiencies. These findings suggest that half of the first episodes of VTE in patients deficient in natural anticoagulants occur before middle age and the risk of VTE recurrence is high in patients with AT deficiency.

Risk of recurrence after venous thromboembolism in men and women: patient level meta-analysis

OBJECTIVE

To determine the effect of sex on the risk of recurrent venous thromboembolism in all patients and in patients with venous thromboembolism that was unprovoked or provoked (by non-hormonal factors). Data source Comprehensive search of electronic databases (Medline, Embase, CINAHL, Cochrane Central Register of Controlled Trials) until July 2010, supplemented by review of conference abstracts and contact with content experts.

STUDY SELECTION

Seven prospective studies investigating an association between D-dimer, measured after anticoagulation was stopped, and disease recurrence in patients with venous thromboembolism.

DATA EXTRACTION

Patient level databases were obtained, transferred to a central database, checked, and completed with further information provided by authors.

DATA SYNTHESIS

2554 patients with a first venous thromboembolism had follow-up for a mean of 27.1 (SD 19.6) months. The one year incidence of recurrent venous thromboembolism was 5.3% (95% confidence interval 4.1% to 6.7%) in women and 9.5% (7.9% to 11.4%) in men, and the three year incidence of recurrence was 9.1% (7.3% to 11.3%) in women and 19.7% (16.5% to 23.4%) in men. Among patients with unprovoked venous thromboembolism, men had a higher risk of recurrence than did women (hazard ratio 2.2, 95% confidence interval 1.7 to 2.8). After adjustment for women with hormone associated initial venous thromboembolism, the risk of recurrence remained higher in men (hazard ratio 1.8, 1.4 to 2.5). In patients with provoked venous thromboembolism, occurring after exposure to a major risk factor, recurrence of disease did not differ between men and women (hazard ratio 1.2, 0.6 to 2.4). In women with hormone associated venous thromboembolism and no other risk factors, recurrence was lower than that in women with unprovoked venous thromboembolism and no previous hormone use (hazard ratio 0.5, 0.3 to 0.8).

CONCLUSION

In patients with a first unprovoked venous thromboembolism, men have a 2.2-fold higher risk of recurrent venous thromboembolism than do women, which remained 1.8-fold higher in men after adjustment for previous hormone associated venous thromboembolism in women. In patients with a first provoked venous thromboembolism, risk of recurrence does not differ between men and women with or without hormone associated venous thromboembolism. Indefinite anticoagulation may be given greater consideration in men than in women after a first venous thromboembolism.

Management of deep vein thrombosis to reduce the incidence of post-thrombotic syndrome

The post-thrombotic syndrome (PTS) is the major chronic sequel of deep vein thrombosis (DVT) of the leg, and is a major socioeconomic challenge. In addition to systematic prophylaxis of DVT in hospitalized patients, effective management of DVT is important to reduce the incidence of PTS. Thrombolysis and thrombectomy are not indicated routinely. Optimal anticoagulation, usually with heparins initially and then with oral warfarin, is important to prevent recurrent DVT, which is a major risk factor for PTS. Following a routine three-month period of anticoagulation, patients with proximal idiopathic DVT should be individually assessed for the benefits and risks of continued oral anticoagulation, including patient preferences. Risk factors for recurrent DVT include active cancer, pregnancy, continued use of oral oestrogens, male sex, obesity, recurrent thrombosis, established PTS, permanent inferior vena caval filters, residual DVT, high fibrin d-dimer and other thrombophilias. Early walking, continued high levels of physical activity and wearing compression stockings for up to two years may also reduce the risk of PTS.

Procoagulant activity, but not number, of microparticles increases with age and in individuals after a single venous thromboembolism

The Calibrated Automated Thrombogram (CAT), a plate-based assay that measures thrombin generation and inhibition in plasma samples, is modified to measure the procoagulant activity of phospholipid associated with plasma microparticles (MP). The assay uses a tissue factor trigger without addition of 4 μM exogenous phospholipid (PL) used in the standard CAT. Calibrated with 4:1 posphatidylcholine- phosphatidylserine (PCPS) liposomes, the assay defines a median of 40 nM procoagulant phospholipid (PPL) equivalents in plasma containing MPs from 50 normal donors, with a range from 20 - 200 nM. Like the standard CAT, the modified assay detected no difference in plasma from 36 individuals with a history of a single episode of venous thromboembolism. However the male cases had double the PPL activity, as measured by rate of thrombin generation, of females; and there was a significant correlation among cases of increased thrombin generation with age. In contrast, there were no gender disparities or age correlations among control plasmas. The findings suggest that procoagulant activity of plasma microparticles, facilitated by a simplified, one-stage plate-based assay, offer a promising avenue of investigation of mechanisms and management of venous thromboembolic disorders.

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

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.