Venous thromboembolism: risk factors for recurrence

Correlates of in-hospital deaths among hospitalizations with pulmonary embolism: findings from the 2001-2008 National Hospital Discharge Survey

BACKGROUND

Deep vein thrombosis and pulmonary embolism (PE) are responsible for substantial mortality, morbidity, and impaired health-related quality of life. The aim of this study was to evaluate the correlates of in-hospital deaths among hospitalizations with a diagnosis of PE in the United States.

METHODS

By using data from the 2001-2008 National Hospital Discharge Survey, we assessed the correlates of in-hospital deaths among 14,721 hospitalizations with a diagnosis of PE and among subgroups stratified by age, sex, race, days of hospital stay, type of admission, cancer, pneumonia, and fractures. We produced adjusted rate ratios (aRR) and 95% confidence intervals using log-linear multivariate regression models.

RESULTS

Regardless of the listing position of diagnostic codes, we observed an increased likelihood of in-hospital death in subgroups of hospitalizations with ages 50 years and older (aRR = 1.82-8.48), less than 7 days of hospital stay (aRR = 1.43-1.57), cancer (aRR = 2.10-2.28), pneumonia (aRR = 1.79-2.20), or fractures (aRR = 2.18) (except for first-listed PE), when compared to the reference groups with ages 1-49 years, 7 days or more of hospital stay, without cancer, pneumonia, or fractures while adjusting for covariates. In addition, we observed an increased likelihood of in-hospital death for first-listed PE in hospitalizations of women, when compared to those of men (aRR = 1.45).

CONCLUSIONS

The results of this study provide support for identifying, developing, and implementing effective, evidence-based clinical assessment and management strategies to reduce PE-related morbidity and mortality among hospitalized PE patients who may have concurrent health conditions including cancer, pneumonia, and fractures.

New insights into the mechanisms of venous thrombosis

Venous thrombosis is a leading cause of morbidity and mortality in industrialized countries, especially in the elderly. Many risk factors have been identified for venous thrombosis that alter blood flow, activate the endothelium, and increase blood coagulation. However, the precise mechanisms that trigger clotting in large veins have not been fully elucidated. The most common site for initiation of the thrombus appears to be the valve pocket sinus, due to its tendency to become hypoxic. Activation of endothelial cells by hypoxia or possibly inflammatory stimuli would lead to surface expression of adhesion receptors that facilitate the binding of circulating leukocytes and microvesicles. Subsequent activation of the leukocytes induces expression of the potent procoagulant protein tissue factor that triggers thrombosis. Understanding the mechanisms of venous thrombosis may lead to the development of new treatments.

Taller women are at greater risk of recurrent venous thromboembolism: the Iowa Women's Health Study

Venous thromboembolism (VTE) recurs frequently. Greater height is associated with increased risk of incident VTE, but it is unclear whether height is related to risk of VTE recurrence. Recurrent VTE is associated with substantial morbidity and mortality, thus identifying individuals at greatest risk of experiencing a recurrent event, who may benefit from extended anticoagulant therapy, is vitally important. Using data from the Iowa Women,s Health Study, we explored whether greater height was associated with increased risk of VTE recurrence.Among 1,691 women who experienced an initial VTE event, 286(16.9%) experienced a recurrent event. Risk of recurrence was 76%(95% CI: 16% -186%) higher among women >66 inches [168 cm] tall relative to those ≤62 inches [158 cm] tall, after adjustment for age and waist circumference. Future research should evaluate whether body height improves clinical prediction of VTE recurrence risk.

Recurrent venous thromboembolism while on anticoagulant therapy

There has been immense progress in the management of venous thromboembolism in recent years with increased awareness and adequate thromboprophylaxis proving successful in reducing the morbidity and mortality associated with this condition. One of the commonest complications of an initial venous thrombosis is the development of recurrent thrombosis. Unlike in the case of the first clot, the diagnosis and management of the recurrent episode remain a difficult issue. Even more challenging is the clinical situation where a new thrombus develops while the patient is being treated with anticoagulant medication for a previous clot. The clinical approach and management of these patients are complex, and require understanding of the differences in thrombus development in the different clinical circumstances.

Predicting the risk of venous thromboembolism recurrence

Venous thromboembolism (VTE) is a chronic disease with a 30% ten-year recurrence rate. The highest incidence of recurrence is in the first 6 months. Active cancer significantly increases the hazard of early recurrence, and the proportions of time on standard heparin with an APTT ≥ 0.2 anti-X(a) U/mL, and on warfarin with an INR ≥ 2.0, significantly reduce the hazard. The acute treatment duration does not affect recurrence risk after treatment is stopped. Independent predictors of late recurrence include increasing patient age and body mass index, leg paresis, active cancer and other persistent VTE risk factors, idiopathic VTE, antiphospholipid antibody syndrome, antithrombin, protein C or protein S deficiency, hyperhomocysteinemia and a persistently increased plasma fibrin D-dimer. A recommendation for secondary prophylaxis should be individualized based on the risk for recurrent VTE (especially fatal pulmonary embolism) and bleeding. The appropriateness of secondary prophylaxis should be continuously reevaluated, and the prophylaxis stopped if the benefit no longer exceeds the risk.

Outpatient use of low molecular weight heparin monotherapy for first-line treatment of venous thromboembolism in advanced cancer

BACKGROUND

Evidence-based treatment guidelines recommend low molecular weight heparin (LMWH) monotherapy for cancer-associated venous thromboembolism (VTE). This analysis assessed the first-line treatment strategies for VTE in patients with advanced solid tumors.

METHODS

Using administrative data from advanced lung, prostate, colon, or breast cancer patients diagnosed between January 2000 and December 2007 at four HMOs with integrated delivery systems, patients with an inpatient or outpatient VTE diagnosed within 2 years after cancer diagnosis and an outpatient purchase of warfarin, LMWH, and/or fondaparinux anticoagulant within 7 days of the VTE diagnosis were identified. First-line outpatient VTE pharmacological treatment and factors independently associated with receipt/non-receipt of LMWH monotherapy were assessed.

RESULTS

Overall, 25% of the 1,089 eligible patients received LMWH monotherapy as primary VTE treatment. The percentage increased steadily over time from 18% among patients diagnosed in 2000 to 31% among those diagnosed in 2007. Factors associated with LMWH monotherapy included VTE diagnosis year, chemotherapy within 60 days prior to VTE diagnosis, history of VTE prior to cancer diagnosis, and invasive surgery in the 90 days following VTE diagnosis. Colorectal and prostate cancer patients versus lung cancer patients and stage III versus stage IV patients were less likely to be treated with LMWH monotherapy.

CONCLUSIONS

Adoption of LMWH monotherapy as initial treatment for cancer-associated VTE was low but increased steadily over the study period. Future studies should explore reasons underlying the underutilization of this preferred evidence-based treatment as well as the comparative effectiveness of LMWH versus warfarin-based anticoagulation in real-world cancer patients with VTE.

Epidemiology of recurrent venous thrombosis

Venous thrombosis, including deep vein thrombosis and pulmonary embolism, is a common disease that frequently recurs. Recurrence can be prevented by anticoagulants, but this comes at the risk of bleeding. Therefore, assessment of the risk of recurrence is important to balance the risks and benefits of anticoagulant treatment. This review briefly outlines what is currently known about the epidemiology of recurrent venous thrombosis, and focuses in more detail on potential new risk factors for venous recurrence. The general implications of these findings in patient management are discussed.

Myeloid cell tissue factor does not contribute to venous thrombogenesis in an electrolytic injury model

INTRODUCTION

Tissue factor (TF) is a potent initiator of the extrinsic coagulation cascade. The role and source of TF in venous thrombotic disease is not clearly defined. Our study objective was to identify the contribution of myeloid cell TF to venous thrombogenesis in mice.

MATERIALS AND METHODS

The mouse electrolytic inferior vena cava model was used to induce thrombosis. The following groups of mice were used (1) TF(flox/flox)LysMCre(+) mice that have reduced TF expression in myeloid cells, (2) TF(flox/flox)LysMCre(-) littermate controls, (3) Wild type mice given a monoclonal anti-mouse TF antibody (1H1) to inhibit TF activity, and (4) Wild type mice given rat IgG. Evaluations at baseline, day 2, and day 6 post thrombosis included thrombus weight, vein wall inflammatory cell migration, vein wall TF mRNA, and plasma D-dimer levels.

RESULTS

Inhibition of TF significantly decreased thrombus weight 2days post venous thrombosis. In contrast, TF(flox/flox)LysMCre(+) had no change in thrombus weight when compared to littermate controls. The absence of myeloid cell TF did not affect infiltration of neutrophils or monocytes into the vein wall. TF mRNA expression in the vein wall decreased at 2days but then returned to baseline levels by 6days post thrombosis. D-dimer levels peaked at 2days post thrombosis in mice with or without myeloid cell TF.

CONCLUSIONS

TF is important in the formation of venous thrombi in the macrovasculature. However, TF expression by myeloid cells does not significantly contribute to venous thrombogenesis in this model.

Cardiac arrest caused by multiple recurrent pulmonary embolism

Pulmonary embolism is a common condition with a high mortality. We describe a previously healthy 68-year-old male who suffered three pulmonary embolisms during a short period of time, including two embolisms while on anticoagulant treatment. This paper illustrates three important points. (1) The importance of optimal anticoagulant treatment in the prevention of pulmonary embolism reoccurrence. (2) The benefit of immediate accessibility to echocardiography in the handling of haemodynamically unstable patients with an unknown underlying cause. (3) Thrombolytic treatment should always be considered and may be life-saving in patients with cardiac arrest suspected to be caused by pulmonary embolism.

[Treatment of deep vein thrombosis and pulmonary embolism]

Deep vein thrombosis and pulmonary embolism may be considered as different manifestations of the same disease: venous thromboembolism. Under the condition of entirely stable hemodynamics, treatment follows exactly the same principles. The phase of initial therapy has a duration of 5-10 days and has remained so far a domain of parenteral anticoagulants (low molecular weight heparin, fondaparinux). The phase of early maintenance therapy is instituted with an overlap and has a duration of 3-6 months; vitamin K antagonists with a target INR of 2.0-3.0 are the standard. Patients with a high risk of recurrence and a low risk of bleeding will enter a phase of prolonged or even indefinite maintenance therapy. Again, vitamin K antagonists with a target INR of 2.0-3.0 are the standard. A target INR of 1.5-2.0 may be considered an alternative for patients in whom a very stable anticoagulation with less frequent INR testing is desirable. Clear recommendations can be made for venous thromboembolism treatment in pregnancy, in the post partum and lactation periods, as well as for patients with severe renal impairment. New anticoagulants (thrombin inhibitors, factor Xa inhibitors) have made significant progress in their clinical development and will soon become available as an alternative for all three phases of therapy.

Impact of venous thromboembolism on clinical management and therapy after hip and knee arthroplasty

Postoperative deep vein thrombosis (DVT) occurs most often in the large veins of the legs in patients undergoing major joint arthroplasty and major surgical procedures. These patients remain at high risk for venous thromboembolic events. In patients undergoing total hip or total knee arthroplasty (THA or TKA, respectively), different patterns of altered venous hemodynamics and hypercoagulability have been found, thus the rate of distal DVT is higher than that of proximal DVT after TKA. In addition, symptomatic venous thromboembolism (VTE) occurs earlier after TKA than THA; however, most of those events occur after hospital discharge. Consequently, extended thromboprophylaxis after discharge should be considered and is particularly important after THA owing to the prolonged risk period for VTE. Evidence-based guideline recommendations for the prevention of VTE in these patients have not been fully implemented. This is partly owing to the limitations of traditional anticoagulants, such as the parenteral route of administration or frequent coagulation monitoring and dose adjustment, as well as concerns about bleeding risks. The introduction of new oral agents (e.g., dabigatran etexilate and rivaroxaban) may facilitate guideline adherence, particularly in the outpatient setting, owing to their oral administration without the need for routine coagulation monitoring. Furthermore, the direct Factor Xa inhibitor rivaroxaban has been shown to be more effective than enoxaparin in preventing VTE.

Association of elevated NTproBNP with recurrent thromboembolic events after acute pulmonary embolism

INTRODUCTION

N-Terminal Pro-Brain Natriuretic Peptide (NTproBNP) is a predictor of adverse short-term clinical outcomes in patients with acute pulmonary embolism (APE), but its long-term prognostic value remains largely undefined. The aim of this study was to assess the value of plasma NTproBNP with regard to recurrent venous thromboembolism (VTE).

MATERIALS AND METHODS

NTproBNP levels were measured in 224 consecutive patients with the first episode of acute pulmonary embolism occurring from January 2005 through October 2010. Patients were categorized into two groups by NTproBNP reference range. Follow-ups were performed at 3, 6, and 12months and yearly thereafter. The primary end point was symptomatic, recurrent fatal or nonfatal VTE.

RESULTS

NTproBNP was elevated in 158 (70.5%) patients and not elevated in 66 (29.5%) patients. After a mean follow-up period of 31.0±19.4months, patients with elevated NTproBNP showed an increased risk of recurrent VTE (20 patients, 12.7%) compared to those without elevated NTproBNP (only 1 patient, 1.5%) (P=0.009). Of the 7 deaths related to pulmonary embolism, 6 occurred in patients with elevated NTproBNP compared to patients with normal NTproBNP (1 of 7 deaths). In a multivariate analysis stratified by oral anticoagulant treatment duration, elevated NTproBNP was an independent predictor of recurrent VTE (hazard ratio, 9.32; P=0.02).

CONCLUSIONS

Elevated NTproBNP is associated with recurrent VTE in acute pulmonary embolism patients.

Venous thromboembolism in patients with reduced estimated GFR: a population-based perspective

BACKGROUND

An increased frequency of venous thromboembolism (VTE) has been shown in patients with decreased kidney function measured by decreased estimated glomerular filtration rate (eGFR). However, present practices with respect to VTE prevention and management in patients with decreased eGFR in general population settings are uncertain.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

Community investigation of 1,509 metropolitan Worcester, MA, residents with a validated VTE in 1999, 2001, and 2003 with further follow-up for up to 3 years.

PREDICTOR

Patients with VTE classified further according to eGFR on presentation: <30, 30-59, 60-89, or ≥90 mL/min/1.73 m(2) (reference group).

OUTCOMES

Recurrent VTE, major bleeding episodes, and all-cause mortality.

MEASUREMENTS

Demographic and clinical characteristics, treatment practices, and study outcomes were extracted from patients' hospital and outpatient medical records; eGFR was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.

RESULTS

Patients with VTE with eGFR <30 mL/min/1.73 m(2) were at increased risk of recurrent VTE (HR, 1.83; 95% CI, 1.03-3.25), major bleeding episodes (HR, 2.30; 95% CI, 1.28-4.16), and all-cause mortality (HR, 1.70; 95% CI, 1.12-2.57) during a 3-year follow-up. Patients with decreased eGFR also presented with more comorbid conditions and were less likely to be discharged on any form of anticoagulant therapy (72.6%, 81.0%, 82.1%, and 87.3% for eGFR <30, 30-59, 60-89, and ≥90 mL/min/1.73 m(2), respectively; P < 0.001).

LIMITATIONS

Decreased eGFR status is presumed based on creatinine values on clinical presentation. The impact of drug dosage, timing, type of anticoagulant therapy, and medication adherence on study outcomes could not be evaluated.

CONCLUSIONS

Severe decreases in eGFR are associated with increased risk of long-term recurrent VTE, bleeding, and total mortality in patients with VTE. A greater frequency of serious comorbid conditions, difficulties implementing available management strategies, and suboptimal VTE prophylaxis during hospital admissions likely contributed to our findings.

Residual vein obstruction as a predictor for recurrent thromboembolic events after a first unprovoked episode: data from the REVERSE cohort study

OBJECTIVES

There is growing interest in using residual vein obstruction (RVO) to guide the duration of oral anticoagulant therapy (OAT) for unprovoked deep vein thrombosis (DVT). We sought to determine if RVO as determined by compression ultrasonography (CUS) after completion of 5-7 months of anticoagulation for unprovoked DVT is associated with an increased risk of recurrent venous thromboembolism (VTE).

MATERIALS AND METHODS

This was a multicentre multinational prospective cohort study undertaken in tertiary care centers. Patients with a first 'unprovoked' major VTE were enrolled over a 4-year period and completed a mean 18-month follow-up in September 2006. All 452 patients with DVT had baseline CUS at inclusion to assess any RVO before stopping OAT at 5-7 months. During follow-up off OAT, all episodes of suspected recurrent VTE were independently adjudicated with reference to baseline imaging.

RESULTS

Forty-five out of 231 patients with abnormal CUS (19.5%) had recurrent VTE during follow-up, as compared with 32 out of 220 patients with normal CUS (14.6%), and one patient had inadequate CUS. There was no significant association between an abnormal CUS at inclusion and the risk of recurrent VTE: hazard ratio 1.4 (95% confidence interval, 0.9-2.1), P=0.19. None of the different degrees of clot resolution on baseline CUS was statistically significantly associated with the risk of recurrent VTE.

CONCLUSION

In our study, the presence of RVO at the time of OAT withdrawal was not associated with a statistically significant higher risk of recurrent VTE. RVO assessment may not be useful to guide duration of anticoagulation.

[Risk factors for recurrent venous thromboembolism]

Recurrent venous thromboembolism (VTE) is frequent and can be fatal. Long-term antithrombotic treatment reduces the risk of recurrent VTE but increases the risk of bleeding and, therefore, cannot be proposed for all patients. Predicting the probability of recurrence in an individual patient is of utmost importance for assessing the risk-benefit ratio of long-term anticoagulation. Multiple clinical risk factors for recurrent VTE have been identified which include: unprovoked first episode, anatomical proximal location, male gender, residual venous thrombosis, cancer and antiphospholipid syndrome. d-dimer level after discontinuation of oral anticoagulation can help to predict the risk of recurrence with a good negative predictive value. Finally, genetic polymorphisms and rare inherited deficiencies of natural anticoagulant proteins do not seem to be strongly associated to recurrence. New antithrombotic drugs may, in the near future, improve the safety and of long-term anticoagulation treatment.

Mortality and recurrence after treatment of VTE: long term follow-up of patients with good life-expectancy

INTRODUCTION

After completed anticoagulant treatment for acute VTE, both the subsequent mortality and risk of recurrent VTE are high, probably related to the frequent presence of serious disease in these patients. The aim of the study was to determine survival and recurrence in selected patients with good life-expectancy, and to evaluate risk factors.

METHODS

The 323 patients were followed for median 7.4 years (range 4.1-11.9) after cessation of anticoagulation. Survival analysis and Cox-regression were used for univariate and multivariate analysis.

RESULTS

The cumulative incidence of survival after 5 years was 93.4%. Standardised mortality ratio was 1.42 for men and 1.28 for women. Patients without a transient risk factor prior to the index VTE were associated with higher risk of mortality compared to risk of mortality in patients with a transient risk factor (hazard ratio (HR) 2.81; 95% CI 1.40-5.62). Recurrence of VTE after 5 years was 19.0%. A persistent risk factor or a spontaneous VTE was associated with higher risk of recurrence compared to a transient risk factor (HR 2.39; 95% CI 1.44-3.95). Elevated D-dimer levels increased the risk, and immobilisation prior to the index VTE reduced the risk of recurrence. Sex, age and thrombophilia were not independent risk factors for recurrence.

CONCLUSIONS

Despite a low mortality rate in this selected cohort, the recurrence rate and risk factors for recurrence were similar to findings reported in unselected populations. VTE unrelated to a transient risk factor was associated with increased mortality compared to mortality in patients with a transient risk factor.

Male mice have increased thrombotic potential: sex differences in a mouse model of venous thrombosis

INTRODUCTION

Our objectives were to characterize sex differences during venous thrombosis, using the electrolytic inferior vena cava model of the disease.

MATERIALS AND METHODS

Male and female C57BL/6 mice (6-8 weeks) underwent inferior vena cava thrombosis. Time points included 6 hours, day 2, day 6, and day 14 post surgery, along with surgically naïve true controls and surgical shams. Analyses included thrombus weight, vein wall morphometrics, vein wall protein and gene expression for P-selectin, interleukin-1β, and tumor necrosis factor-α; hematology, soluble P-selectin, and plasma microparticle tissue factor activity assays.

RESULTS

Male venous thrombi were significantly larger than females at days 2 (13.1 ± 1.0 vs. 6.8 ± 0.5 × 10(-3) grams, p < 0.01), 6 (10.4 ± 0.8 vs. 5.4 ± 0.5 × 10(-3) grams, p < 0.01) and 14 (6.3 ± 0.5 vs. 4.1 ± 0.3 × 10(-3) grams, p < 0.01). Both male and female mice exhibited significantly increased vein wall P-selectin at 6 hours, vs. true controls (p < 0.05). Males had increased vein wall interleukin-1β, versus females, at 6 hours (180.926 ± 24.596 vs. 60.417 ± 10.478 pg/mL, p < 0.05) and day 6 (76.966 ± 13.081 vs. 33.834 ± 4.198 pg/mL, p < 0.01). Males showed decreased tumor necrosis factor-α expression (-66 %) at 6 hours. Females had increased tumor necrosis factor-α expression at 6 hours (+541%) and day 6 (+539%). Both sexes demonstrated decreased peripheral platelets at 6 hours (p < 0.05), coinciding with thrombogenesis. Plasma P-selectin increased in both sexes, versus controls, through day 6 (p < 0.05).

CONCLUSIONS

Males had significantly larger venous thrombi than females. Sex differences in vascular anatomy and response to inflammation may influence thrombus formation in our mouse thrombosis model.

An update on etiology, prevention, and therapy of postthrombotic syndrome

Postthrombotic syndrome is a common sequelae resulting from deep venous thrombosis. The primary interventions are prevention and treatment, both of which many vascular specialists may not always recognize. We review the definition, epidemiology, the basic pathophysiology, and preventative management for postthrombotic syndrome. The current primary medical and interventional treatment modalities to decrease the occurrence of postthrombotic syndrome are also highlighted. Many of these treatments are currently available and simply need to be adhered to, whereas others are a shift in the paradigm, focusing on active thrombus removal.

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.

Sex difference in risk of recurrent venous thrombosis and the risk profile for a second event

BACKGROUND

The risk of recurrent venous thrombosis is higher in men than in women, and this is so far unexplained. We set out to determine the influence of age, time between first and second event, type of first event, oral contraception, pregnancy and surgery.

METHODS

We performed a prospective follow-up study of 474 patients with a first objective diagnosis of deep vein thrombosis, aged 18-70 years (Leiden Thrombophilia Study cohort).

RESULTS

During 3477 person-years of follow-up, 90 recurrences occurred. The overall incidence rates of recurrence (IRs) were 40.9 per 1000 person-years in men and 15.8 per 1000 person-years in women. Men with an unprovoked first event had the highest risk of recurrence, with almost one-third experiencing a second unprovoked event within 8 years (IR 41.2 per 1000 person-years). This risk was three-fold lower in women [IR 14.2 per 1000 person-years; hazard ratio 2.8 (95% confidence interval 1.4-5.7)]. Age at diagnosis had little effect on recurrence rate, and nor had time elapsed since the first event. In women, almost half of the recurrences were provoked and were mainly related to oral contraceptive use or pregnancy.

CONCLUSIONS

The higher recurrence rate in men than in women is not the result of differences in the environmental or transient risk factors that we studied. The risk profile for a second thrombotic event is clearly different from that of a first.

Inflammatory bowel disease is a risk factor for recurrent venous thromboembolism

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) are at increased risk of a first venous thromboembolism (VTE), yet their risk of recurrent VTE is unknown. We performed a cohort study to determine the risk for recurrent VTE among patients with IBD compared with subjects without IBD.

METHODS

We assessed 2811 patients with IBD for a history of VTE, recruited from outpatient clinics at 14 referral centers (June 2006-December 2008). Patients with VTE before a diagnosis of IBD or those not confirmed to have VTE, cancer, or a VTE other than deep vein thrombosis or pulmonary embolism, were excluded. Recurrence rates were compared with 1255 prospectively followed patients without IBD that had a first unprovoked VTE (not triggered by trauma, surgery, or pregnancy). The primary end point was symptomatic, objectively confirmed, recurrent VTE after discontinuation of anticoagulation therapy after a first VTE.

RESULTS

Overall, of 116 IBD patients who had a history of first VTE, 86 were unprovoked. The probability of recurrence 5 years after discontinuation of anticoagulation therapy was higher among patients with IBD than patients without IBD (33.4%; 95% confidence interval [CI]: 21.8-45.0 vs 21.7%; 95% CI: 18.8-24.6; P = .01). After adjustment for potential confounders, IBD was an independent risk factor of recurrence (hazard ratio = 2.5; 95% CI: 1.4-4.2; P = .001).

CONCLUSIONS

Patients with IBD are at an increased risk of recurrent VTE compared to patients without IBD.

Venous thromboembolic events after cerebral vein thrombosis

BACKGROUND AND PURPOSE

After cerebral vein and dural sinus thrombosis (CVT), there is an increased risk of further venous thromboembolic events (VTEs). Time to a second cerebral or systemic venous thrombotic event and risk factors for recurrence have not been investigated in large prospective studies.

METHODS

We used the International Study on Cerebral Vein and Dural sinus Thrombosis, which included 624 patients with CVT followed up for a median of 13.9 months. Outcome measures included all symptomatic VTEs and CVT recurrence. Potential predictors of recurrence, including demographic characteristics, imaging features, thrombophilic abnormalities, other risk factors for CVT, and anticoagulation, were analyzed by Cox survival analysis.

RESULTS

Of the 624 included patients, 36 (5.8%) had at least 1 venous thromboembolic event. The rate of VTEs after the initial CVT was 4.1 per 100 person-years. Of all VTEs, 63.2% (n=24) occurred within the first year. Fourteen patients (2.2%) had an episode of recurrent CVT and the rate of recurrence was 1.5 per 100 person-years. Nine (64.3%) of these CVT recurrences occurred within the first year. Male gender (hazard ratios=2.6; 95% CI, 1.4 to 5.1; P=0.004) and polycythemia/thrombocythemia (hazard ratios=4.4; 95% CI, 1.6 to 12.7; P=0.005) were the only factors associated with a significant higher risk of VTEs in multivariate survival analysis.

CONCLUSIONS

The risk of recurrence of CVT is low but is moderate for other VTEs. Recurrence of venous thrombosis after CVT is more frequent among men and in patients with polycythemia/thrombocythemia.

Recurrent venous thromboembolism after surgery-provoked versus unprovoked thromboembolism

SUMMARY BACKGROUND

The incidence of recurrent venous thromboembolism (VTE) varies depending on the nature of the initial provoking risk factor(s).

OBJECTIVES

To compare the incidence and time course of recurrent VTE after unprovoked VTE vs. VTE provoked by nine different types of surgery.

METHODS

Retrospective analysis of linked California hospital and emergency department discharge records. Between 1997 and 2007, all surgery-provoked VTE cases had a first-time VTE event diagnosed within 60 days after undergoing a major operation. The incidence of recurrent VTE was compared during specified follow-up periods by matching each surgery-provoked case with three unprovoked cases based on age, race, gender, VTE event, calendar year and co-morbidity.

RESULTS

The 4-year Kaplan-Meier cumulative incidence of recurrent VTE was 14.7% (95%CI: 14.2-15.1) in the matched unprovoked VTE group vs. 7.6% (CI: 7.0-8.2) in 11 797 patients with surgery-provoked VTE (P < 0.001). The overall risk reduction was 48%, which ranged from 64% lower risk (P < 0.001) after coronary bypass surgery to 25% lower risk (P = 0.06) after disc surgery. The risk of recurrent VTE 1-5 years after the index event was significantly lower in the surgery group (HR = 0.47, CI: 0.41-0.53). Within the surgery-provoked group, the risk of recurrent VTE was similar in men and women (HR = 1.0, CI: 0.8-1.3).

CONCLUSIONS

The risk of recurrent VTE after surgery-provoked VTE was approximately 50% lower than after unprovoked VTE, confirming the view that provoked VTE is associated with a lower risk of recurrent VTE. However, there was appreciable heterogeneity in the relative risk of recurrent VTE associated with different operations.

Risk Assessment of Recurrence in Patients With Unprovoked Deep Vein Thrombosis or Pulmonary Embolism

Background— Predicting the risk of recurrent venous thromboembolism (VTE) in an individual patient is often not feasible. We aimed to develop a simple risk assessment model that improves prediction of the recurrence risk.

Methods and Results— In a prospective cohort study, 929 patients with a first unprovoked VTE were followed up for a median of 43.3 months after discontinuation of anticoagulation. We excluded patients with a strong thrombophilic defect such as a natural inhibitor deficiency, the lupus anticoagulant, and homozygous or combined defects. A total of 176 patients (18.9%) had recurrent VTE. Preselected clinical and laboratory variables (age, sex, location of VTE, body mass index, factor V Leiden, prothrombin G20210A mutation, D-dimer, and in vitro thrombin generation) were analyzed in a Cox proportional hazards model, and those variables that were significantly associated with recurrence were used to compute risk scores. Male sex (hazard ratio versus female sex 1.90, 95% confidence interval 1.31 to 2.75), proximal deep vein thrombosis (hazard ratio versus distal 2.08, 95% confidence interval 1.16 to 3.74), pulmonary embolism (hazard ratio versus distal thrombosis 2.60, 95% confidence interval 1.49 to 4.53), and elevated levels of D-dimer (hazard ratio per doubling 1.27, 95% confidence interval 1.08 to 1.51) were related to a higher recurrence risk. Using these variables, we developed a nomogram that can be used to calculate risk scores and to estimate the cumulative probability of recurrence in an individual patient. The model was cross validated, and patients were assigned to different risk categories based on their risk score. Recurrence rates corresponded well with the different risk categories.

Conclusions— By use of a simple scoring system, the assessment of the recurrence risk in patients with a first unprovoked VTE and without strong thrombophilic defects can be improved.

Update on perioperative bridging in patients on chronic oral anticoagulation

Oral anticoagulation (OAC) with vitamin K antagonists is commonly used for long-term prevention or treatment of arterial or venous thromboembolism. In the USA alone, approximately 250,000 patients will require temporary interruption of OAC annually. Managing anticoagulation in those patients on chronic OAC who require invasive procedures continues to be a major clinical dilemma. This article summarizes the existing evidence in light of the recommendations of the American College of Chest Physicians. Management of anticoagulation in the perioperative period will continue to be an important clinical challenge and an evolving area of research. If new oral anticoagulants are successful in replacing warfarin, the entire perioperative anticoagulation scene will change.

Testing low-risk patients for suspected pulmonary embolism: a decision analysis

STUDY OBJECTIVE

The Pulmonary Embolism Rule-out Criteria (PERC) identifies low-risk patients who are treated in the emergency department for suspected pulmonary embolism and for whom testing may be deferred. The purpose of this study is to develop a decision model to determine whether certain elements not included in the PERC methodology could better estimate the testing threshold for pulmonary embolism (ie, the pretest probability below which a patient should not be tested for pulmonary embolism). In addition, we determine which risks and benefits of pulmonary embolism evaluation and treatment have the greatest effect on the testing threshold.

METHODS

We built decision models of low-risk patients with suspected pulmonary embolism, as determined by the PERC. We obtained model inputs from the literature or by using clinical judgment when data were unavailable. One-way sensitivity analysis derived the testing threshold, and 2-way sensitivity analysis was used to determine the main drivers of the testing threshold.

RESULTS

We found an average testing threshold of 1.4% across all age and sex cohorts. Two-way sensitivity analysis demonstrated that risk of major bleeding from anticoagulation, mortality from contrast-induced renal failure, risk of cancer from computed tomography scan, and mortality from both treated and untreated pulmonary embolism had the greatest effects on the testing threshold.

CONCLUSION

We found a testing threshold for the PERC similar to that calculated by the Pauker and Kassirer method, using somewhat different assumptions. The 5 major drivers for the testing threshold are variables for which there is a paucity of literature to assess accurately for low-risk patients.

Hyperhomocysteinemia in patients with pulmonary embolism

Investigation of hyperhomocysteinemia (HHcy) as an important risk factor for pulmonary thromboembolism (PTE), which represents a most dangerous consequence of a unique phenomenon of venous thromboembolism which still suffers from sometimes conflicting or inadequately clarified results. The role of homocysteine in the clinical manifestation of this life-threatening disease and its treatment (in which any further information may be decisive) requires detailed examination. The purpose of this study is to determine the differences in HHcy incidence and homocysteinemia levels between patients with PTE and healthy persons. The study enrolled 70 patients with PTE and 50 healthy persons. Homocysteine was measured using the HPLC method with fluorescent detection and HHcy was defined as homocysteinemia above 12 ?mol/L. Statistical analyses included chi-square and Mann Whitney U tests. The median homocysteinemia value was significantly higher (p=0.017) in the patients (12.10 ?mol/L) than in the controls (10.35 ?mol/L). The comparison of HHcy incidence between the patients (51.5%) and controls (30%) revealed a significant difference (p=0.021). In patients, homocysteinemia was significantly higher (p=0.002) in men (14.05?mol/L) than in women (10.01 ?mol/L). HHcy was present in 67.6% of men with PTE, which was significantly higher (p=0.006) than the incidence in women with PTE (33.3%). Healthy males had significantly higher (p=0.001) homocysteinemia (12.54 ?mol/L) than healthy females (9.4 ?mol/L). A significant difference (p=0.031) was observed between the incidences of HHcy in healthy males (44.0%) and healthy females (16.0%). We conclude that the incidence of hyperhomocysteinemia and homocysteinemia are significantly higher in all the patients compared with the healthy persons, as well as in both healthy males and males with PTE compared with healthy females and female patients. This indicates that HHcy findings in PE are likely to have a clinical importance.

[Deep venous thrombosis as a marker of tumor recurrence]

BACKGROUND AND OBJECTIVE

There is a bidirectional association between neoplasia and venous thromboembolism (VTE). However, whether this association has an impact in tumor recurrence is unknown. The aim of the study is to assess the incidence of cancer recurrence after diagnosis of VTE and determine if VTE could be a marker for cancer recurrence.

PATIENTS AND METHOD

This was a retrospective cohort observational study. The observations were made in June 2008. The study included 132 patients diagnosed with a deep vein thrombosis (DVT) between January 2002 and December 2005 and had a cancer without activity in the last 12 months in their medical history. The cancer recurrence was assessed. The sample was divided according to the presence or absence of cancer recurrence and study variables were compared.

RESULTS

The incidence of cancer recurrence after diagnosis with DVT was 50,7%. This recurrence occurred in the first 4 months in 55,2% and more frequent and earlier in patients with breast tumors (p:00014), with carcinoma (p:0,02), in patients under palliative chemotherapy and in patients with previous presence of metastasis. (p:0,00).

CONCLUSIONS

In 50,7% of patients without neoplasic activity in the last year, DVT was the first sign of tumor recurrence. These patients should be referred to an oncology department as soon as possible in order to diagnose the tumor recurrence.