Risk factors for venous thromboembolism in pregnancy.

Venous thromboembolism remains the leading cause of maternal mortality in the United Kingdom. In this review we highlight studies that have documented the incidence of objectively confirmed venous thromboembolism in pregnancy, consider the effect of pregnancy on the coagulation and fibrinolytic systems, and examine in detail current knowledge of the risk factors for the development of this condition.     

Risk factors for venous thromboembolism

Venous thromboembolism is a common and potentially lethal disease. Patients who have pulmonary embolism are at especially high risk for death. Death owing to pulmonary embolism is independent of other comorbid conditions (e.g., cancer, chronic heart disease, or lung disease). Sudden death is often the first clinical manifestation. Only a reduction in the incidence of venous thromboembolism can reduce sudden death owing to pulmonary embolism and venous stasis syndrome owing to deep vein thrombosis. The incidence of venous thromboembolism has been relatively constant since about 1980. Improvement in the incidence of venous thromboembolism will require better recognition of persons at risk, improved estimates of the magnitude of risk, the avoidance of risk exposure when possible, more widespread use of safe and effective prophylaxis when risk is unavoidable, and targeting of prophylaxis to those persons who will benefit most. Recognition of venous thromboembolism as a multifactorial disease with genetic and genetic-environmental interaction has provided significant insights into its epidemiology and offers the possibility of improved identification of persons at risk for incident and recurrent venous thromboembolism.     

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.     

老年人静脉血栓栓塞症的危险因素

静脉血栓栓塞症(VTE)包括深静脉血栓形成(DVT)和肺栓塞(PE),其发生率随着年龄的增高而显著上升,老年人是VTE的高危人群。随着人口老龄化加剧,老年VTE患者势必不断增多。明确老年人VTE危险因素,及时采取有效预防措施,具有重要的现实意义。本文综述了与老年人VTE发生较为密切的一些因素,包括制动相关危险因素、癌症、老年人常见慢性病、慢性静脉功能不全、衰弱综合征等,以期发现其特点,为老年人VTE预防提供可靠的临床参考。     

Risk factors for venous thromboembolism after lung transplantation

BACKGROUND: The risk factors for venous thromboembolism (VTE) following lung transplantation are not well established. We aimed to estimate the incidence of VTE and to identify the risk factors for VTE after lung transplantation. METHODS: We performed a nested case-control study within the cohort of 121 patients who underwent lung transplantation at our center between August 2001 and July 2005. Control subjects were matched to case patients on the number of days from the time of transplant. Cox proportional hazards models were used to identify risk factors for VTE. RESULTS: Twenty-four patients had deep vein thromboses, and 6 patients had pulmonary emboli (3 patients had both) [22% of the cohort]. In multivariate models, older age (p < 0.05), diabetes mellitus (p = 0.03), and pneumonia (p = 0.02) were associated with a higher rate of VTE. CONCLUSIONS: VTE is a frequent complication of lung transplantation. Older age, diabetes, and pneumonia increase the rate of VTE. Future studies of intensive VTE prophylaxis may be warranted.     

Risk factors for venous thromboembolism in immunoglobulin light chain amyloidosis

Patients with immunoglobulin light chain amyloidosis are at risk for both thrombotic and bleeding complications. While the hemostatic defects have been extensively studied, less is known about thrombotic complications in this disease. This retrospective study examined the frequency of venous thromboembolism in 929 patients with immunoglobulin light chain amyloidosis presenting to a single referral center, correlated risk of venous thromboembolism with clinical and laboratory factors, and examined complications of anticoagulation in this population. Sixty-five patients (7%) were documented as having at least one venous thromboembolic event. Eighty percent of these patients had events within one year prior to or following diagnosis. Lower serum albumin was associated with increased risk of VTE, with a hazard ratio of 4.30 (CI 1.60–11.55; P=0.0038) for serum albumin less than 3 g/dL compared to serum albumin greater than 4 g/dL. Severe bleeding complications were observed in 5 out of 57 patients with venous thromboembolism undergoing treatment with anticoagulation. Prospective investigation should be undertaken to better risk stratify these patients and to determine the optimal strategies for prophylaxis against and management of venous thromboembolism.     

非小细胞肺癌合并静脉血栓栓塞症危险因素研究

目的 探讨非小细胞肺癌(NSCLC)患者发生静脉血栓栓塞症(VTE)的危险因素.方法 回顾性分析2005年1月至2016年1月新疆医科大学第一附属医院收治的57例NSCLC合并VTE患者的资料,选取同期在我院确诊为NSCLC的患者105例,用二元logistic回归分析NSCLC患者并发VTE的可能危险因素.结果 二元logistic回归多因素分析显示,化疗(OR =5.91,95％CI:1.47～10.76)、白细胞＞11×109/L(OR=7.54,95％ CI:1.69～13.25)、白蛋白＜35 g/L(OR =5.25,95％ CI:1.89～12.42)、D-二聚体＞500 μg/L(OR=25.16,95％ CI:7.87～80.41)与NSCLC患者发生VTE存在显著的相关关系.结论 化疗、白细胞＞1i×109/L、白蛋白＜35 g/L、D-二聚体＞500 μg/L是NSCLC患者并发VTE的独立危险因素.     

Risk factors for in-hospital venous thromboembolism in children: a case-control study employing diagnostic validation

Background

Studies evaluating risk factors for in-hospital venous thromboembolism in children are limited by quality assurance of case definition and/or lack of controlled comparison. The objective of this study is to determine risk factors for the development of in-hospital venous thromboembolism in children.

Design and Methods

In a case-control study at The Children’s Hospital, Colorado, from 1^st January 2003 to 31^st December 2009 we employed diagnostic validation methods to determine pediatric in-hospital venous thromboembolism risk factors. Clinical data on putative risk factors were retrospectively collected from medical records of children with International Classification of Diseases, 9th edition codes of venous thromboembolism at discharge, in whom radiological reports confirmed venous thromboembolism and no signs/symptoms of venous thromboembolism were noted on admission.

Results

We verified 78 cases of in-hospital venous thromboembolism, yielding an average incidence of 5 per 10,000 hospitalized children per year. Logistical regression analyses revealed that mechanical ventilation, systemic infection, and hospitalization duration of five days or over were statistically significant, independent risk factors for in-hospital venous thromboembolism (OR=3.29, 95%CI=1.53–7.06, P=0.002; OR=3.05, 95%CI=1.57–5.94, P=0.001; and OR=1.03, 95%CI=1.01–1.04, P=0.001, respectively). Using these factors in a risk model, post-test probability of venous thromboembolism was 3.6%.

Conclusions

These data indicate that risk of in-hospital venous thromboembolism in children with this risk factor combination may exceed that of hospitalized adults in whom prophylactic anticoagulation is indicated. Substantiation of these findings via multicenter studies could provide the basis for future risk-stratified randomized control trials of pediatric venous thromboembolism prevention.     

Risk factors for venous thromboembolism after total hip and knee replacement surgery

Elective total hip and total knee arthroplasty surgeries are associated with an extraordinarily high incidence of asymptomatic venous thromboembolism (VTE). Symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) is diagnosed in only 2%-4% of these patients. A number of studies have defined the incidence and time course of symptomatic thromboembolism after these procedures. Knee arthroplasty is associated with a very high incidence of asymptomatic calf vein thrombosis, with almost all symptomatic VTE events diagnosed in the first 21 days after surgery. Hip arthroplasty, however, is associated with a higher incidence of asymptomatic proximal thrombi and a modestly higher incidence of symptomatic VTE events, many diagnosed up to 6 or 8 weeks after hospital discharge. Extended medical thromboprophylaxis has been shown to reduce the incidence of symptomatic and asymptomatic VTE among hip arthroplasty patients but not among knee arthroplasty patients. Risk factors for VTE after knee arthroplasty are not well defined. Important risk factors that have been shown to be associated with the development of VTE after hip surgery include (1) a history of prior VTE, (2) obesity (body mass index > 25), (3) delay in ambulation after surgery, and (4) female sex. Factors associated with lower risk include (1) Asian/Pacific Islander ethnicity, (2) use of pneumatic compression among non-obese patients after surgery, and (3) extended thromboprophylaxis after hospital discharge.     

Risk factors for venous thromboembolism in the elderly: results of the master registry

Approximately 50-75% of patients with venous thromboembolism have a readily identifiable risk factor, either transient or permanent, whereas the remaining episodes are classified as unprovoked. The incidence of first-time venous thromboembolism rises exponentially with age. Whether the prevalence and the relative weight of major risk factors differ between elderly and younger patients is unclear. We performed a multicenter, prospective, observational study on consecutive patients with objectively confirmed acute venous thromboembolism admitted to 25 Italian hospitals. Baseline characteristics and information on temporary and permanent risk factors at the time of the index event were secured by an electronic data network. We enrolled 2119 patients (49.8% men), of whom 440 (20%) were more than 75 years of age and 1679 (79.2%) 75 years of age or less. Elderly patients were more likely to have pulmonary embolism at presentation (33.6 and 25.6%, respectively, P < 0.001). After binary logistic regression analysis, we found that the risk of venous thromboembolism in the elderly, compared with the younger age group, was significantly associated with immobilization (odds ratio: 2.46, 95% confidence interval: 1.85-3.27) and with severe medical disorders (odds ratio: 1.99, 95% confidence interval: 1.41-2.80), whereas male sex (odds ratio: 0.53, 95% confidence interval: 0.42-0.66), surgery (odds ratio: 0.61, 95% confidence interval: 0.43-0.85), and trauma (odds ratio: 0.49, 95% confidence interval: 0.31-0.77) were less common risk factors in the elderly than in younger patients. Use of thromboprophylaxis prior to the index event was not different between the two age groups. Severe medical disorders and immobilization are strongly associated with the occurrence of venous thromboembolism in the elderly. Our findings stress the need for adequate thromboprophylaxis in this setting.     

Risk factors for venous thromboembolism (VTE) recurrences in Thai patients without cancer

Introduction: Studies in Western countries show that VTE recurrent rates are lower in the presence of a transient provoking factor, older age, female sex and/or hormonal use, while thrombophilia (factor V Leiden or prothrombin mutation) has no predictive role. This study aimed to determine the incidence and risk factors of recurrent VTE in Asian patients.

Method: This is a retrospective cohort study in adult VTE patients who were diagnosed during 2004–2014, had no active cancer and followed-up for at least 1 year.

Results: There were 198 patients. The mean age was 58.2?±?17.6 years and 68.2% were female. The diagnoses were deep vein thrombosis (56%), pulmonary embolism (32%) or both (12%). They were provoked by major surgery in 21.7%. Thrombophilia (antiphospholipid syndrome or protein C or protein S deficiency) was found in 11.6%. The recurrent rate during the median follow-up time of 52 months was 2.2 (95% confidence interval [CI] 1.46–3.31) per 100 patient-years. Presence of thrombophilia was independently associated with recurrences with the adjusted hazard ratio (aHR) of 3.52 (95% CI 1.32–9.42, p?=?0.01). There were 144 patients who discontinued anticoagulants. During the median time of 55 months after stopping anticoagulants, the recurrent rate was 4.3 per 100 patient-years. Thrombophilia was associated with recurrences with aHR of 4.00 (95% CI 1.42–11.31, p?=?0.01), while male sex, younger age, provoking conditions and hormone use showed no significant association.

Conclusion: VTE recurrent rate in Asians is comparable to Caucasians, but thrombophilia is the strongest risk factor.     

Diagnosis of venous thromboembolism in children

Venous thromboembolic events (VTE) in children are mostly related to central venous lines (CVL), and are located in the central upper venous system. The incidence of VTE in children with CVL is significant. However, the majority of CVL-related VTE do not present with typical symptoms or are not recognized due to underlying disease. Asymptomatic VTE still cause significant venous obstruction and are associated with short-term and long-term clinical complications. Because the clinical diagnosis of CVL-related VTE is unreliable, screening by objective radiographic testing is required. In the upper venous system, ultrasound is insensitive for the VTE in the central venous system and venography is not sensitive for jugular VTE. Therefore, a combination of ultrasound and venography is required for accurate diagnosis of CVL-related VTE in the upper venous system. Whether ultrasound alone is accurate for CVL-related VTE in the lower venous system is uncertain. Magnetic resonance venography will likely prove a valid alternative for diagnosis of VTE both in the upper and lower central venous system, and may be combined with magnetic resonance pulmonary angiography to screen for pulmonary embolism.     

Risk of venous thromboembolism in lung cancer

PURPOSE OF REVIEW: To evaluate venous thromboembolism (VTE) risk factors in lung cancer patients. RECENT FINDINGS: VTE incidence is around 40-100 cases per 1000 person-years in lung carcinoma patients vs. an estimated 1-2 cases per 1000 person-years in the general population. Patients with adenocarcinoma have higher risk of VTE than patients with squamous cell lung carcinoma. VTE risk appears two-fold higher in nonsmall-cell lung cancer than in small-cell lung cancer patients. Other risk factors are pneumonectomy, metastatic disease, use of specific chemotherapeutic drugs in combination with novel targeted drugs, such as antiangiogenic agents, and elevated prechemotherapy platelet counts. Tissue factor (TF), the initiator of the clotting cascade, may be (over)expressed in lung carcinoma cells. Active TF-bearing microparticles, which may originate from the tumour cells themselves, have been found in the circulation of cancer patients. Microparticle-associated TF activity may provide a link between cancer and thrombosis and play a decisive role in the pathogenesis of the prothrombotic state in cancer patients. SUMMARY: Risk factors of VTE in lung cancer patients are adenocarcinoma, metastatic disease, pneumonectomy and anticancer therapy including chemotherapy and anti-VEGF targeted drugs. Other risk factors include pretreatment platelet counts and active TF-expressing circulating microparticles.