Incidence of arterial cardiovascular events after venous thromboembolism: a systematic review and a meta-analysis

How I treat the co-occurrence of venous and arterial thromboembolism: anticoagulation, antiplatelet therapy, or both?

ABSTRACT

Arterial and venous thromboses are classically considered distinct disease states, with arterial thrombosis mediated predominantly by platelets and therefore, treated with antiplatelet therapy, and venous thrombosis mediated by the plasmatic coagulation system and treated with anticoagulation. However, co-occurrence of arterial and venous events is common, and there is increasing evidence of shared risk factors and pathophysiologic overlap. This presents a management challenge: does the patient with venous and arterial thrombosis, require anticoagulation, antiplatelet therapy, or both? Herein, we present a structured approach to the evaluation and management of patients with venous thrombosis who are also at risk for or have a history of an arterial thromboembolic event. We emphasize the importance of defining the indications for antithrombotic therapy, as well as the evaluation of factors that influence both thrombotic and bleeding risk, including disorder-specific and patient-specific factors, as well as the inherent risk balance of antithrombotic therapy regimens. We illustrate this approach in 4 cases, discussing the unique considerations and recent updates in the management of venous thrombosis, acute noncardioembolic ischemic stroke, coronary artery disease and acute myocardial infarction, and peripheral artery disease after revascularization.

Multimorbidity disease clusters are associated with venous thromboembolism: an extended cross-sectional national study

Multimorbidity, i.e., two or more non-communicable diseases (NCDs), is an escalating challenge for society. Venous thromboembolism (VTE) is a common cardiovascular disease and it is unknown which multimorbidity clusters associates with VTE. Our aim was to examine the association between different common disease clusters of multimorbidity and VTE. The study is an extended (1997-2015) cross-sectional Swedish study using the National Patient Register and the Multigeneration Register. A total of 2,694,442 Swedish-born individuals were included in the study. Multimorbidity was defined by 45 NCDs. A principal component analysis (PCA) identified multimorbidity disease clusters. Odds ratios (OR) for VTE were calculated for the different multimorbidity disease clusters. There were 16% (n = 440,742) of multimorbid individuals in the study population. Forty-four of the individual 45 NCDs were associated with VTE. The PCA analysis identified nine multimorbidity disease clusters, F1-F9. Seven of these multimorbidity clusters were associated with VTE. The adjusted OR for VTE in the multimorbid patients was for the first three clusters: F1 (cardiometabolic diseases) 3.44 (95%CI 3.24-3.65), F2 (mental disorders) 2.25 (95%CI 2.14-2.37) and F3 (digestive system diseases) 4.35 (95%CI 3.63-5.22). There was an association between multimorbidity severity and OR for VTE. For instance, the occurrence of at least five diseases was in F1 and F2 associated with ORs for VTE: 8.17 (95%CI 6.32-10.55) and 6.31 (95%CI 4.34-9.17), respectively. In this nationwide study we have shown a strong association between VTE and different multimorbidity disease clusters that might be useful for VTE prediction.

Causes of death after first time venous thromboembolism

BACKGROUND

Causes of death after first time community-acquired venous thromboembolism (VTE) diagnosed in unselected patients at the emergency department (ED) was investigated.

MATERIALS AND METHODS

The study consists of all patients > 18 years of age who had a visit for any medical reason to any of 5 different ED in Stockholm County, Sweden from 1st January 2016 to 31st December 2017. We have identified all patients with a first registered incident VTE; deep vein thrombosis (DVT) and/or pulmonary embolism (PE) during the study period. Cox regression models were used to estimate hazards ratios (HR) with 95% confidence intervals (CIs) for all-cause mortality and cause-specific death in patients with DVT or PE using all other patients as the reference group.

RESULTS

In total, 359,884 patients had an ED visit during the study period of whom about 2.1% were diagnosed with VTE (DVT = 4,384, PE = 3,212). The patients with VTE were older compared to the control group. During a mean follow up of 2.1 years, 1567 (21%) and 23,741(6.7%) patients died within the VTE and reference group, respectively. The adjusted risk of all-cause mortality was nearly double in patients with DVT (HR 1.7; 95% CI, 1.5-1.8) and more than 3-fold in patients with PE (HR 3.4; 95% CI, 3.1-3.6). While the risk of cancer related death was nearly 3-fold in patient with DVT (HR 2.7; 95% CI, 2.4-3.1), and 5-fold in PE (HR 5.4; 95% CI, 4.9-6.0 respectively). The diagnosis of PE during the ED visit was associated with a significantly higher risk of cardiovascular death (HR 2.2; 95% CI, 1.9-2.6).

CONCLUSION

Patients with VTE have an elevated risk of all-cause mortality, including cardiovascular death.

Heterogeneous distributions in clinical events preceding anticoagulant treatment nonpersistence in patients with venous thromboembolism stratified by active cancer: A nationwide cohort study

BACKGROUND

Nonpersistence in anticoagulation therapy is common and associated with undesirable clinical outcomes in patients with venous thromboembolism (VTE).

METHODS

We investigated preceding clinical events of treatment nonpersistence (e.g., switching, discontinuing, or restarting) in VTE patients with and without active cancer using Korean claims database.

RESULTS

Clinically significant events including thromboembolic events, hepatic function change and surgery preceded treatment nonpersistence, but heterogeneous distributions of clinical events were observed in the presence of active cancer. Patients with active cancer had a low rate of clinical events preceding treatment nonpersistence, and new active cancer diagnosis in the nonactive cancer group was most common before the switch to parenteral anticoagulants from warfarin or non-vitamin K antagonist oral anticoagulants (NOACs).

CONCLUSION

These findings suggest that clinically significant events can precede treatment nonpersistence and largely paralleled current guidelines for patients with VTE, whereas heterogeneous distributions of clinical events were observed in the presence of active cancer.

A hypothesis - generating Swedish extended national cross-sectional family study of multimorbidity severity and venous thromboembolism

OBJECTIVES

Venous thromboembolism (VTE) is a common worldwide disease. The burden of multimorbidity, that is, two or more chronic diseases, has increased. Whether multimorbidity is associated with VTE risk remains to be studied. Our aim was to determine any association between multimorbidity and VTE and any possible shared familial susceptibility.

DESIGN

A nationwide extended cross-sectional hypothesis - generating family study between 1997 and 2015.

SETTING

The Swedish Multigeneration Register, the National Patient Register, the Total Population Register and the Swedish cause of death register were linked.

PARTICIPANTS

2 694 442 unique individuals were analysed for VTE and multimorbidity.

MAIN OUTCOMES AND MEASURES

Multimorbidity was determined by a counting method using 45 non-communicable diseases. Multimorbidity was defined by the occurrence of ≥2 diseases. A multimorbidity score was constructed defined by 0, 1, 2, 3, 4 or 5 or more diseases.

RESULTS

Sixteen percent (n=440 742) of the study population was multimorbid. Of the multimorbid patients, 58% were females. There was an association between multimorbidity and VTE. The adjusted odds ratio (OR) for VTE in individuals with multimorbidity (2 ≥ diagnoses) was 3.16 (95% CI: 3.06 to 3.27) compared with individuals without multimorbidity. There was an association between number of diseases and VTE. The adjusted OR was 1.94 (95% CI: 1.86 to 2.02) for one disease, 2.93 (95% CI: 2.80 to 3.08) for two diseases, 4.07 (95% CI: 3.85 to 4.31) for three diseases, 5.46 (95% CI: 5.10 to 5.85) for four diseases and 9.08 (95% CI: 8.56 to 9.64) for 5 ≥ diseases. The association between multimorbidity and VTE was stronger in males OR 3.45 (3.29 to 3.62) than in females OR 2.91 (2.77 to 3.04). There were significant but mostly weak familial associations between multimorbidity in relatives and VTE.

CONCLUSIONS

Increasing multimorbidity exhibits a strong and increasing association with VTE. Familial associations suggest a weak shared familial susceptibility. The association between multimorbidity and VTE suggests that future cohort studies where multimorbidity is used to predict VTE might be worthwhile.

Sex‐specific aspects of venous thromboembolism: What is new and what is next?

Men seem to have a higher intrinsic risk of venous thromboembolism (VTE) than women, regardless of age. To date, this difference has not been explained. By integrating state‐of‐the‐art research presented at the International Society on Thrombosis and Haemostasis Congress of 2021 with the available literature, we address potential explanations for this intriguing risk difference between men and women. We discuss the role of exogenous and endogenous sex hormones as the most important known sex‐specific determinants of VTE risk. In addition, we highlight clues on the role of sex hormones and VTE risk from clinical scenarios such as pregnancy and the polycystic ovary syndrome. Furthermore, we address new potential sex‐specific risk factors and unanswered research questions, which could provide more insight in the intrinsic risk difference between men and women, such as body height and differences in body fat distribution, leading to dysregulation of metabolism and inflammation.

Potential Association between Distal Deep Vein Thrombosis and Asymptomatic Atherosclerosis

Background  Several studies have previously reported an association between idiopathic proximal deep vein thrombosis (DVT) and atherosclerosis, but whether spontaneous distal DVT is associated with asymptomatic atherosclerosis is still unknown.

Methods  Ultrasonography of the carotid arteries was done for plaque detection and intima-media thickness (IMT) evaluation, and the ankle-brachial index (ABI) in 116 patients with spontaneous DVT and without symptomatic atherosclerosis. Fifty-seven patients (M/F 19/38, age range 54–78 years) had distal DVT and 59 (M/F 24/35, age range 51–73 years) had proximal DVT. A group of 57 (M/F 21/36, age range 64–70 years) matched subjects acted as controls.

Results  No significant difference was found in carotid plaques between patients with distal or proximal DVT versus controls ( p > 0.05 in all comparisons). Carotid IMT (mean ± SD) was significantly increased in patients with distal (1.00 ± 0.20 mm) and proximal (0.98 ± 0.16 mm) DVT versus controls (0.88 ± 0.15 mm, p <0.01 in both comparisons). An ABI £ 0.9 was found in 3/57 (5.3%) and 5/59 (8.5%) patients with distal and proximal DVT, respectively versus no controls with abnormal ABI.

Conclusion  Our results revealed that there may be an association between spontaneous distal DVT and asymptomatic atherosclerosis, and confirmed the known association between idiopathic proximal DVT and asymptomatic atherosclerosis. Larger studies are needed to confirm our results and to evaluate their clinical implications.

Accelerated fibrin clot degradation is associated with arterial thromboembolism in patients following venous thrombosis: a cohort study

Several lines of evidence have suggested that patients following venous thromboembolism (VTE) are at higher risk of arterial thromboembolism (ATE). Prothrombotic fibrin clot characteristics were reported in individuals with cardiovascular risk factors. We investigated whether specific fibrin clot properties measured after 3-4 months of anticoagulation characterize VTE patients with subsequent ATE. We enrolled 320 patients following VTE aged below 70 years (median age, 46). Ten patients were lost to follow-up. ATE occurred in 21 individuals after a median 54 (31-68) months during a follow-up of 87.5 months (incidence 0.94%; 95% confidence interval [CI], 0.59-1.4 per patient-year). Patients with ATE had faster fibrin clot degradation, reflected by maximum rate of D-dimer increase during plasma clot lysis induced by tissue-type plasminogen activator (D-D_rate) at baseline. Clot permeability, turbidimetric variables, clot lysis time, and thrombin generation were unrelated to ATE. Univariable Cox proportional hazards analysis showed that age, diabetes, and D-D_rate were risk factors for subsequent ATE. Increased D-D_rate (by 0.001 mg/L/min; hazard ratio, 1.08; 95% CI 1.02-1.14) was an independent predictor of ATE after adjustment for potential confounders. Faster fibrin clot degradation at 3 months since VTE may increase the risk of ATE among VTE patients during follow-up.

Neurological Complications of Pulmonary Embolism: a Literature Review

PURPOSE OF REVIEW

The present review discusses in-depth about neurological complications following acute venous thromboembolism (VTE).

RECENT FINDINGS

Intracranial hemorrhage, acute ischemic cerebrovascular events, and VTE in brain tumors are described as central nervous system (CNS) complications of PE, while peripheral neuropathy and neuropathic pain are reported as peripheral nervous system (PNS) sequelae of PE. Syncope and seizure are illustrated as atypical neurological presentations of PE. Mounting evidence suggests higher risk of venous thromboembolism (VTE) in patients with neurological diseases, but data on reverse, i.e., neurological sequelae following VTE, is underexplored. The present review is an attempt to explore some of the latter issues categorized into CNS, PNS, and atypical complications following VTE.

Derivation and validation of a clinical prediction model for risks of venous thromboembolism in diabetic and general populations

Most studies on the prediction of venous thromboembolism (VTE) focused on hospitalized, surgery, and cancer patients or women receiving hormonal contraceptives or menopausal hormone therapy. No study considered diabetic and general populations to establish a VTE prediction model, especially in Asia. We developed a predictive model for VTE among type 2 diabetic patients and the general population.This study considered 2 nationwide retrospective cohort studies consisting of 52,427 diabetic participants and 508,664 participants from the general population aged 30 to 85 years during 2001 to 2004 in Taiwan. All participants were followed up until VTE event, death, or December 2011. The outcome event was VTE, including deep venous thrombosis and pulmonary embolism. Candidate predictors consisted of socio-demographic factors, diabetes-related factors and biomarkers, comorbidities, and medicine use. Our study followed the procedures proposed by the Framingham Heart Study to develop prediction models by using a Cox regression model. The predictive accuracy and performance characteristics were assessed using the area under curve of receiver operating characteristics curve and calibration of a risk score were performed by Hosmer-Lemeshow goodness-of-fit test.The common factors for persons with type 2 diabetes and general population included age, hospitalization status 1 year before the baseline, hypertension, chronic kidney disease, chronic obstructive pulmonary disease, and anti-diabetes medications; the specific factors for persons with type 2 diabetes consisted of body mass index, glycosylated hemoglobin A1C, and creatinine; and the factors for general population included gender, peripheral vascular disease, cancer, hypertension medication, cardiovascular medication, and non-steroidal anti-inflammatory drug. The area under curve of 3-, 5-, and 8-year VTE prediction models were 0.74, 0.71, and 0.69 in the diabetic population and 0.77, 0.76, and 0.75 in the general population, respectively.The new clinical prediction models can help identify a high risk of VTE and provide medical intervention in diabetic and general populations.

Is Hematopoietic Clonality of Indetermined Potential a Risk Factor for Pulmonary Embolism?

Background  Unprovoked pulmonary embolism (uPE) is a severe and frequent condition. Identification of new risk factors is mandatory to identify patients that would benefit from a long-term treatment. Clonal hematopoiesis of indeterminate potential (CHIP) is defined by the acquisition of somatic mutations that drive clonal expansion in the absence of cytopenia. Its prevalence is estimated of 5% in the population above 65 years. Since inflammation and endothelial dysfunction may share a pathophysiological pathway(1), we hypothesized that CHIP, may be a risk factor for uPE.

Methods  We conducted a pilot retrospective observational study. Patients with iPE between 18 to 65 years old were included. PE was considered as unprovoked, when no transient nor persistant risk factor was present and when thrombophilia testing was negative. We excluded documented atherosclerosis, personal or familial history of VTE and presence of cytopenias. CHIP proportion in uPE patients were analyzed using next generation sequencing of the coding sequence of a custom panel composed by DNMT3A, ASXL1, SF3B1, TET2 and TP 53 .

Results  Upon 61 patients with uPE consecutively included, a total of 19 somatic mutations were found in 12 patients (20%) IC95% [10 - 20]. 15 mutations were found in DNMT3A gene, 3 in ASXL1 and one in TET2 . There was no diference in terms of age, PE location, DVT presence and risk stratification in CHIP carriers and non carriers.

Conclusion  We report for the first time, the presence of high rates of CHIP in patients presenting with uPE. Thus, CHIP may be a new risk factor for VTE. These results need to be confirmed in an ongoing prospective case-control study including more patients and using a more diverse gene panel to better determine CHIP incidence in uPE.

The effect of deep vein thrombosis on major adverse limb events in diabetic patients: a nationwide retrospective cohort study

Little is known about the association between deep vein thrombosis (DVT) and arterial complications in patients with type 2 diabetes (T2DM). The aim of this retrospective cohort study was to assess the influence of prior DVT on major adverse limb events (MALEs) and major adverse cardiovascular events (MACEs) in T2DM. A total of 1,628,675 patients with T2DM with or without a history of DVT from 2001 to 2013 were identified in the National Health Insurance Research Database of Taiwan. Before matching, the patients in the DVT group (n = 2020) were older than the control group (66.3 vs. 58.3 years). Patients in the DVT group were more likely to be female than the control group (54.3% vs. 47.5%). Before matching, the DVT group had higher prevalence of most comorbidities, more prescription of antiplatelet, antihypertensive agents and insulins, but less prescription of metformin and sulfonylurea. During a mean follow-up of 5.2 years (standard deviation: 3.9 years), the matched DVT group (n = 2017) have a significantly increased risk of MALE (8.4% vs. 5.2%; subdistribution hazard ratio [SHR] 1.60, 95% CI 1.34–1.90), foot ulcer (5.2% vs. 2.6%, SHR 1.96, 95% CI 1.57–2.45), gangrene (3.4% vs. 2.3%, SHR 1.44, 95% CI 1.10–1.90) and amputation (2.5% vs. 1.7%; SHR 1.42, 95% CI 1.03–1.95) than the 10,085 matched controls without DVT. They also tended to have a greater risk of all-cause mortality (38.1% vs. 33.1%; hazard ratio [HR] 1.18, 95% CI 1.09–1.27) and systemic thromboembolism (4.2% vs. 2.6%; SHR 1.56, 95% CI 1.22–1.99), respectively. We showed the presence of DVT may be associated with an increased risk of MALEs, major amputation, and thromboembolism, contributing to a higher mortality rate in T2DM.

Identification of common and divergent gene expression signatures in patients with venous and arterial thrombosis using data from public repositories

STRENGTHS AND LIMITATIONS OF THIS STUDY

Our results represent the first comparison of venous and arterial thrombosis at the transcriptomic level.Our main result was the demonstration that immunothrombosis pathways are important to the pathophysiology of these conditions, also at the transcriptomic level.A specific signature for venous and arterial thrombosis was described, and validated in independent cohorts.The limited number of public repositories with gene expression data from patients with venous thromboembolism limits the representation of these patients in our analyses.In order to gather a meaningful number of studies with gene expression data we had to include patients in different time-points since the index thrombotic event, which might have increased the heterogeneity of our population.

Is there a link between venous and arterial thrombosis? A reappraisal

Whether there is a link between venous and arterial thrombotic disorders is still a matter of debate. They share common risk factors, such as old age, male sex and obesity. Endothelial dysfunction and inflammation are likely to play a role in determining the simultaneous involvement of the two vascular compartments. Unlike subclinical atherosclerosis, symptomatic complications of atherosclerosis such as myocardial infarction, ischemic stroke and atrial fibrillation are likely to predict the subsequent development of venous thromboembolic (VTE) complications. Patients with VTE, especially those with apparently unprovoked episodes, have a definitely increased risk of subsequent arterial thrombotic disorders. Drugs that reduce the risk of arterial thrombosis are likely to reduce the risk of venous thrombosis and vice versa. In particular, the direct oral anticoagulants have recently been shown to reduce the risk of both vascular disorders. In conclusion, recent evidence provides compelling evidence in support of the link between venous and arterial thrombosis. Future studies are needed to clarify the nature of this association, to assess its extent, and to evaluate its implications for clinical practice.

Increased systemic arterial stiffness in patients with chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of venous thromboembolism (VTE) resulting from non-dissolving thromboemboli in the pulmonary arteries. Previous observations indicate a higher prevalence of atherosclerosis and cardiovascular risk factors in patients with VTE and CTEPH. The purpose of the present study was to evaluate the arterial stiffening assessed by pulse wave velocity (PWV), a marker of arterial stiffness, in CTEPH patients in comparison with a matched control group (CG).

METHODS

The study group consisted of 26 CTEPH patients (9 male and 17 female, age 69 ± 10 years) and 22 CG (10 male, 12 female, age 67 ± 8 years). In all subjects a physical examination, carotid-femoral PWV and transthoracic echocardiography were performed. Right heart catheterization was done in all CTEPH.

RESULTS

Chronic tromboembolic pulmonary hypertension patients had significantly higher PWV than CG (10.3 ± 2.5 m/s vs. 9 ± 1.3 m/s, p < 0.05), even though systolic blood pressure was higher in CG (120 ± 11 vs. 132 ± 14 mmHg, p = 0.002). PWV correlated only with age and pulmonary vascular resistance (PVR) in CTEPH (r = 0.45, p = 0.03 and r = 0.43, p = 0.03, respectively). Arterial stiffening defined as PWV > 10 m/s was found in 11 (42%) CTEPH patients and in 5 (23%) cases from CG (p = 0.13). CTEPH patients with PWV > 10 m/s were older (74 ± 8 vs. 66 ± 10 years, p < 0.05), had decreased oxygen saturation (SaO2 89 [73-96]% vs. 96 [85-98]%, p < 0.01) and tended to have higher PVR (8.1 [3.1-14.0] vs. 5.2 [3.1-12.7] HRU, p = 0.10).

CONCLUSIONS

Arterial stiffness, assessed with PWV, is increased in CTEPH. The elevated PWV is associated with older age, lower SaO2 and higher PVR in CTEPH.

Venous thromboembolism has the same risk factors as atherosclerosis: A PRISMA-compliant systemic review and meta-analysis

BACKGROUND

Previous studies have shown that idiopathic pulmonary embolism is positively associated with other cardiovascular events, such as myocardial infarction and stroke, suggesting a potentially important association between atherosclerosis risk factors and venous thromboembolism (VTE). We performed a meta-analysis to evaluate the correlation between risk factors for atherosclerosis and VTE.

METHODS

In December 2014, we searched MEDLINE and EMBASE for studies evaluating the associations between VTE and risk factors for atherosclerosis and pooled outcome data using random-effects meta-analysis. In addition, we analyzed publication bias.

RESULTS

Thirty-three case-control and cohort studies with a total of 185,124 patients met the inclusion criteria. We found that participants with body mass index (BMI) ≥30 kg/m had a significantly higher prevalence of VTE than those with BMI <30 kg/m in both case-control studies (odds ratio [OR] = 2.45, 95% confidence interval [CI]: 1.78-3.35) and cohort studies (relative risk [RR] = 2.39, 95% CI: 1.79-3.17). VTE was more prevalent in patients with hypertension than without hypertension (OR = 1.40, 95% CI: 1.06-1.84; RR = 1.36, 95% CI: 1.11-1.67). The findings were similar for VTE prevalence between patients with and without diabetes (OR = 1.78, 95% CI: 1.17-2.69; RR = 1.41, 95% CI: 1.20-1.66). Current smoking was significantly associated with VTE prevalence in case-control studies (OR = 1.34, 95% CI: 1.01-1.77), but not in cohort studies (RR = 1.29, 95% CI: 0.96-1.72). In addition, we found that total cholesterol and triglyceride concentrations were significantly higher in patients with VTE than without VTE (weighted mean differences [WMD] = 8.94 mg/dL, 95% CI: 3.52-14.35 mg/dL, and WMD = 14.00 mg/dL, 95% CI: 8.85-19.16 mg/dL, respectively). High-density lipoprotein cholesterol concentrations were significantly lower in patients with VTE than without VTE (WMD = -2.03 mg/dL, 95% CI: -3.42 to -0.63 mg/dL). Higher quality studies were more homogeneous, but confirmed the same significant associations.

CONCLUSIONS

Based on our systematic review and meta-analysis, we observed a significant association between VTE and the risk factors for atherosclerosis. These results may make an important contribution to clinical practice regarding VTE treatment.

Influence of statin use on the incidence of recurrent venous thromboembolism and major bleeding in patients receiving rivaroxaban or standard anticoagulant therapy

Background

Statins may reduce the risk of first and recurrent venous thromboembolism (VTE). No data are available on their potential benefit in patients treated with the oral anticoagulant rivaroxaban.

Methods

The EINSTEIN DVT/PE and EINSTEIN Extension studies compared rivaroxaban with standard of care (n=8280) and placebo (n=1188), respectively. The incidences of recurrent VTE and major bleeding per 100 patient-years for exposure (or not) to statins were calculated. A Cox proportional hazards model was constructed, stratified by index event and intended treatment duration, with statin use as a time-dependent variable, for each treatment group (rivaroxaban vs enoxaparin/vitamin K antagonist or placebo) and adjusted for relevant variables.

Results

In EINSTEIN DVT/PE, 1509 (18.3%) patients used statins during the at-risk period, and 6731 (81.7%) did not. Overall, 2.6 recurrent VTEs occurred per 100 patient-years with statin use compared with 3.8 per 100 patient-years without statins (adjusted hazard ratio [HR] 0.76; 95% confidence interval [CI] 0.46–1.25). HRs for recurrent VTE were similar for concomitant use of rivaroxaban-statin and enoxaparin/VKA-statin. Major bleeding events occurred in 3.0 per 100 patient-years with statin use compared with 2.3 per 100 patient-years without statins (adjusted HR 0.77; 95% CI 0.46–1.29). Due to adjustments in the Cox regression model, the direction of this HR is in contrast to the crude comparison. In EINSTEIN Extension, no recurrent VTEs occurred with statin use in the rivaroxaban group compared with 1.6 per 100 patient-years without statins. In the placebo group, 12.2 recurrent VTEs occurred per 100 patient-years with statin use compared with 13.2 per 100 patient-years without (adjusted HR 0.81; 95% CI 0.35–1.86).

Conclusions

The effect of statins in this secondary analysis of the EINSTEIN VTE treatment program is consistent with other studies that suggest a reduced risk of recurrent VTE, but conclusive evidence of this benefit is lacking. Statins are simple to use, inexpensive, very safe and do not cause bleeding. Therefore, the potential effect on reducing recurrent VTE, which is in the range of that of acetylsalicylic acid, deserves evaluation in a large randomized trial.

Trial registration number

ClinicalTrials.gov: EINSTEIN PE, NCT00439777; EINSTEIN DVT, NCT00440193; EINSTEIN Extension, NCT00439725.

Association between the metabolic syndrome, its individual components, and unprovoked venous thromboembolism: results of a patient-level meta-analysis

OBJECTIVE

The metabolic syndrome (MetS) may contribute to the pathogenesis of venous thromboembolism (VTE), but this association requires additional investigation.

APPROACH AND RESULTS

We performed a patient-level meta-analysis of case-control and cohort studies that evaluated the role of MetS and risk of unprovoked VTE. For case-control studies, odds ratios and 95% confidence intervals were calculated using logistic regression analysis to estimate the influence of individual variables on the risk of VTE; χ(2) tests for trend were used to investigate the effect of increasing number of components of MetS on the risk of VTE and to explore the influence of abdominal obesity on this relationship. For cohort studies, hazard ratios and 95% confidence interval were calculated using multivariable Cox regression analysis. Six case-control studies were included (908 cases with unprovoked VTE and 1794 controls): in multivariate analysis, MetS was independently associated with VTE (odds ratio, 1.91; 95% confidence interval, 1.57-2.33), and both MetS and abdominal obesity were better predictors of unprovoked VTE than obesity defined by the body mass index. Two prospective cohort studies were included (26,531 subjects and 289 unprovoked VTE events): age, obesity, and abdominal obesity, but not MetS were associated with VTE.

CONCLUSIONS

Case-control but not prospective cohort studies support an association between MetS and VTE. Abdominal adiposity is a strong risk factor for VTE.

Are myocardial infarction and venous thromboembolism associated? Population-based case-control and cohort studies

INTRODUCTION

Because the association of myocardial infarction (MI) and venous thromboembolism (VTE) is uncertain, we tested MI as a VTE risk factor and VTE as a predictor of MI.

MATERIALS AND METHODS

Using Rochester Epidemiology Project resources, we identified all Olmsted County, MN residents with objectively-diagnosed incident VTE over the 13-year period, 1988-2000 (n=1311), one to two resident controls per VTE case (n=1511), and all residents with incident MI over the 31-year period, 1979-2010. For VTE cases and controls, we reviewed their complete medical records in the community for VTE and MI risk factors. Using conditional logistic regression we tested MI as a potential VTE risk factor, both unadjusted and after adjusting for VTE risk factors. We also followed VTE cases and controls without prior MI forward in time for incident MI through 12/31/2010, and using Cox proportional hazards modeling, tested VTE as a predictor of MI, both unadjusted and after adjusting for MI risk factors.

RESULTS

The number (%) of MI prior to VTE among cases and controls were 75 (5.7) and 51 (3.4), respectively, and the number (%) of MI after VTE among cases and controls were 58 (4.4) and 77 (5.1), respectively. In univariate analyses, MI was significantly associated with VTE but not after adjusting for VTE risk factors. In both univariate and multivariate analyses, VTE (overall or idiopathic) was not a predictor of MI.

CONCLUSIONS

MI is not an independent risk factor for VTE, and VTE is not a predictor of MI.

Recurrent arterial and venous thromboemboli as initial presentation of acute promyelocytic leukemia

We report a case of a 52-year-old Caucasian woman diagnosed with a synchronic arterial and venous thrombosis as an initial presentation of an acute promyelocytic leukemia (APL). After the diagnosis, the patient was treated with all trans-retinoic acid and arsenic chemotherapy concomitant to systemic anticoagulation. This treatment regimen led to a complete remission and absence of relapse of the thrombosis or APL during the follow-up. To our knowledge, this presentation is the second case in the literature. We use this opportunity to emphasize the importance of performing a complete medical evaluation in cases of unusual thromboembolic events.

Procoagulant activity in hemostasis and thrombosis: Virchow's triad revisited

Virchow's triad is traditionally invoked to explain pathophysiologic mechanisms leading to thrombosis, alleging concerted roles for abnormalities in blood composition, vessel wall components, and blood flow in the development of arterial and venous thrombosis. Given the tissue-specific bleeding observed in hemophilia patients, it may be instructive to consider the principles of Virchow's triad when investigating mechanisms operant in hemostatic disorders as well. Blood composition (the function of circulating blood cells and plasma proteins) is the most well studied component of the triad. For example, increased levels of plasma procoagulant proteins such as prothrombin and fibrinogen are established risk factors for thrombosis, whereas deficiencies in plasma factors VIII and IX result in bleeding (hemophilia A and B, respectively). Vessel wall (cellular) components contribute adhesion molecules that recruit circulating leukocytes and platelets to sites of vascular damage, tissue factor, which provides a procoagulant signal of vascular breach, and a surface upon which coagulation complexes are assembled. Blood flow is often characterized by 2 key variables: shear rate and shear stress. Shear rate affects several aspects of coagulation, including transport rates of platelets and plasma proteins to and from the injury site, platelet activation, and the kinetics of fibrin monomer formation and polymerization. Shear stress modulates adhesion rates of platelets and expression of adhesion molecules and procoagulant activity on endothelial cells lining the blood vessels. That no one abnormality in any component of Virchow's triad fully predicts coagulopathy a priori suggests coagulopathies are complex, multifactorial, and interactive. In this review, we focus on contributions of blood composition, vascular cells, and blood flow to hemostasis and thrombosis, and suggest that cross-talk among the 3 components of Virchow's triad is necessary for hemostasis and determines propensity for thrombosis or bleeding. Investigative models that permit interplay among these components are necessary to understand the operant pathophysiology, and effectively treat and prevent thrombotic and bleeding disorders.

Arterial and venous thrombosis in cancer patients

The most frequent ultimate cause of death is myocardial arrest. In many cases this is due to myocardial hypoxia, generally arising from failure of the coronary macro- and microcirculation to deliver enough oxygenated red cells to the cardiomyocytes. The principle reason for this is occlusive thrombosis, either by isolated circulating thrombi, or by rupture of upstream plaque. However, an additionally serious pathology causing potentially fatal stress to the heart is extra-cardiac disease, such as pulmonary hypertension. A primary cause of the latter is pulmonary embolus, considered to be a venous thromboembolism. Whilst the thrombotic scenario has for decades been the dominating paradigm in cardiovascular disease, these issues have, until recently, been infrequently considered in cancer. However, there is now a developing view that cancer is also a thrombotic disease, and notably a disease predominantly of the venous circulation, manifesting as deep vein thrombosis and pulmonary embolism. Indeed, for many, a venous thromboembolism is one of the first symptoms of a developing cancer. Furthermore, many of the standard chemotherapies in cancer are prothrombotic. Accordingly, thromboprophylaxis in cancer with heparins or oral anticoagulation (such as Warfarin), especially in high risk groups (such as those who are immobile and on high dose chemotherapy), may be an important therapy. The objective of this communication is to summarise current views on the epidemiology and pathophysiology of arterial and venous thrombosis in cancer.