Lipid levels do not influence the risk of venous thromboembolism

Use of the RCOG risk assessment model and biomarkers to evaluate the risk of postpartum venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality during pregnancy and the puerperium. The vast majority of VTE occurs after childbirth. China has not yet established standard risk assessment model for postpartum venous thromboembolism (VTE), the Royal College of Obstetricians and Gynecologists (RCOG) risk assessment model (RAM) is commonly used in clinic at present. Herein, we aimed to evaluate the validity of the RCOG RAM in the Chinese population and try to formulate a local risk assessment model by combining with other biomarkers for VTE prophylaxis.

METHODS

The retrospective study was conducted from January 2019 to December 2021at Shanghai First Maternity and Infant Hospital which has approximately 30,000 births annually, and the incidence of VTE, differences between RCOG-recommended risk factors, and other biological indicators from medical records were evaluated.

RESULTS

The study included VTE (n = 146) and non-VTE(n = 413) women who examined by imaging for suspicion of postpartum VTE. There was no statistical difference in the incidence rate of postpartum VTE between the low-score group (23.8%) and the high-score group (28%) after stratification by RCOG RAM. However, we found that cesarean section (in the low-score group), white blood cell (WBC) ≥ 8.64*10^9/L (in the high-score group), low-density lipoprotein(LDL) ≥ 2.70 mmol/L, and D-dimer ≥ 3.04 mg/L (in both groups) were highly associated with postpartum VTE. Subsequently, the validity of the RCOG RAM combined with biomarkers as a model for the risk assessment of VTE was estimated and the results showed that this model has good accuracy, sensitivity, and specificity.

CONCLUSIONS

Our study indicated that the RCOG RAM was not the best strategy for predicting postpartum VTE. Combined with some biomarkers (including the value of LDL and D-Dimer, and WBC count), the RCOG RAM is more efficient when identifying high-risk groups of postpartum VTE in the Chinese population.

TRIAL REGISTRATION

This purely observational study does not require registration based on ICMJE guidelines.

A two-sample Mendelian randomization study of circulating lipids and deep venous thrombosis

In view of the current debate about the relationship between lipids and deep venous thrombosis (DVT) in clinical studies, a two-sample Mendelian randomization (MR) study was conducted to clarify the effects of five circulating lipids (apolipoprotein A1, apolipoprotein B, low-density lipoprotein, high-density lipoprotein and triglycerides) on DVT from the perspective of genetic inheritance. Five lipids (exposure) were analysed by MR with DVT (outcome) from two different data sources. For the analysis, we used inverse variance weighting and a weighted mode, weighted median, simple mode and MR-Egger regression to analyse the effect of circulating lipids on DVT. In addition, we used the MR-Egger intercept test, Cochran's Q test and "leave-one-out" sensitivity analysis to evaluate horizontal multiplicity, heterogeneity and stability, respectively, in the analysis. In the analysis, the two-sample Mendelian randomization analysis of five common circulating lipids and DVT showed that common circulating lipids had no causal effect on DVT, which is somewhat inconsistent with the findings of many published observational studies. Based on our results, our two-sample MR analysis failed to detect a statistically significant causal relationship between five common circulating lipids and DVT.

A bidirectional Mendelian randomized study of classical blood lipids and venous thrombosis

There is still some controversy about the relationship between lipids and venous thrombosis (VTE). A bidirectional Mendelian randomization (MR) study was conducted to clarify the causal relationship between three classical lipids (low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides (TGs)) and venous thromboembolism (VTE) (deep venous thrombosis (DVT) and pulmonary embolism (PE)). Three classical lipids and VTE were analysed by bidirectional Mendelian randomization (MR). We used the random effect inverse variance weighted (IVW) model as the main analysis model and the weighted median method, simple mode method, weighted mode method and MR-Egger methods as supplementary methods. The leave-one-out test was used to determine the influence of outliers. The heterogeneity was calculated by using Cochran Q statistics in the MR-Egger and IVW methods. The intercept term in the MR‒Egger regression was used to indicate whether horizontal pleiotropy affected the results of the MR analysis. In addition, MR-PRESSO identified outlier single-nucleotide polymorphisms (SNPs) and obtained a stable result by removing outlier SNPs and then performing MR analysis. When we used three classical lipids (LDL, HDL and TGs) as exposure variables, no causal relationship between them and VTE (DVT and PE) was found. In addition, we did not find significant causal effects of VTE on the three classical lipids in reverse MR analysis. There is no significant causal relationship between three classical lipids (LDL, HDL and TGs) and VTE (DVT and PE) from a genetic point of view.

Association Between Blood Lipid Levels and Lower Extremity Deep Venous Thrombosis: A Population-Based Cohort Study

ObjectsTo investigate the potential clinical significance between blood lipid levels and lower extremity deep venous thrombosis (LEDVT). Methods: This cohort study included 500 participants, contains 246 patients with LEDVT and 254 patients without LEDVT. The characteristics including age, sex, body mass index (BMI), disease course, ill position, smoking history, history of current illness, drug administration were collected. And blood lipid levels and other clinical parameters including triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), activated partial thromboplastin time (APTT), thromboplastin time (TT), prothrombin time (PT), and fibrinogen (FIB), neutrophils (NEUT), platelet (PLT), lymphocyte count (LY) were observed. Univariate and multivariate logistic regression analyses were applied. In the present study we particularly focused on the potential associations between blood lipid levels and LEDVT. Results: The risk of LEDVT in participants with HDL-C levels of 0.965 to 1.14 mmol/L, 1.14 to 1.36 mmol/L, and >1.36 mmol/L were 0.366, 0.183, 0.203 times than in controls (<0.965 mmol/L), respectively. Compared to individuals with ApoA1 <1.06 mmol/L, individuals with ApoA1 levels of 1.06 to 1.22 mmol/L, 1.22 to 1.38 mmol/L, and >1.38 mmol/L were related to a decreased risk of LEDVT. The risk of LEDVT in patients with TG levels of 0.985 to 1.37 mmol/L, 1.37 to 1.91 mmol/L, and >1.91 mmol/L were 2.243, 2.224, and 2.540 times higher than that of those with TG <0.985 mmol/L, respectively. The risk of LEDVT in subjects with 4.57< TC <5.17 mmol/L was 0.471-fold than that of those with TC <3.97 mmol/L. Conclusion: The present study indicates that higher levesl of HDL-C and ApoA1 could be associated with a decreased risk of LEDVT, while higher TG levels might be associated with an increased risk of LEDVT. In addition, within the normal range, high TC levels were associated with decreased risk of LEDVT. These findings may help clinicals to identify early and treat those patients with a high-risk of LEDVT at proper time, which could improve patients’ life quality.

PCSK9 Monoclonal Antibodies: New Developments and Their Relevance in a Nucleic Acid-Based Therapy Era

Purpose of Review

To report on recent data about PCSK9 monoclonal antibodies and to evaluate their relevance in a nucleic acid–based therapy era for lipid lowering and prevention of cardiovascular disease.

Recent Findings

New methods of PCSK9 inhibition based on nucleic acid therapeutics such as antisense oligonucleotides, small interfering RNAs, and CRISPR tools for therapeutic gene editing are reported, and interesting new data regarding the clinical relevance of PCSK9 antibodies are discussed.

Summary

Promising methods of PCSK9 inhibition are in development, and one of them, the siRNA inclisiran targeting PCSK9, has already been approved for clinical use. However, PCSK9-mAb remains the PCSK9-inhibiting tool with the longest safety data and the only one having positive cardiovascular outcome trials. An ongoing cardiovascular outcome trial with inclisiran is planned to be completed in 2026. Other forms of PCSK9 inhibition, such as antisense oligonucleotides targeting PCSK9 and CRISPR base editing of PCSK9, are still in early phases of development, and their potential clinical relevance remains to be established.

Non-Lipid Effects of PCSK9 Monoclonal Antibodies on Vessel Wall

Elevated low density lipoprotein (LDL) cholesterol and lipoprotein(a) (Lp(a)) levels have an important role in the development and progression of atherosclerosis, followed by cardiovascular events. Besides statins and other lipid-modifying drugs, PCSK9 monoclonal antibodies are known to reduce hyperlipidemia. PCSK9 monoclonal antibodies decrease LDL cholesterol levels through inducing the upregulation of the LDL receptors and moderately decrease Lp(a) levels. In addition, PCSK9 monoclonal antibodies have shown non-lipid effects. PCSK9 monoclonal antibodies reduce platelet aggregation and activation, and increase platelet responsiveness to acetylsalicylic acid. Evolocumab as well as alirocumab decrease an incidence of venous thromboembolism, which is associated with the decrease of Lp(a) values. Besides interweaving in haemostasis, PCSK9 monoclonal antibodies play an important role in reducing the inflammation and improving the endothelial function. The aim of this review is to present the mechanisms of PCSK9 monoclonal antibodies on the aforementioned risk factors.

Serum Albumin and Circulating Metabolites and Risk of Venous Thromboembolism: A Two-Sample Mendelian Randomization Study

Background and Aim: Previous observational studies indicated that the serum albumin levels and circulating metabolites are associated with a high risk of venous thromboembolism (VTE). However, whether these observations reflect causality remained unclear. Hence, we conducted a two-sample Mendelian randomization (MR) analysis to evaluate the causal associations of serum albumin and circulating metabolites with the risk of VTE.

Methods and Results: Summary statistics of genetic instruments proxying serum albumin, total protein, and common circulating metabolites were extracted from genome-wide association studies in the European ancestry. Summary-level results of age- and sex-adjusted estimates for associations of the instruments with VTE were derived from the FinnGen consortium. We used the inverse-variance weighted (IVW) method as the primary analysis for univariable MR. Sensitivity analyses were performed to detect horizontal pleiotropy and outliers. Genetically proxied high-serum albumin and total protein levels were suggestive protective factor of VTE, with odds ratio (OR) = 0.69 (CI 0.54–0.89, p = 4.7 × 10⁻³) and 0.76 (CI 0.61–0.95, p = 0.015), respectively. Genetically proxied low-monounsaturated fatty acids and the ratio of monounsaturated fatty acid to total fatty acid are causally associated with increased risk of VTE, with ORs = 0.89 (CI 0.80–0.99, p = 0.031) and 0.85 (CI 0.78–0.94, p = 9.92 × 10⁻⁴), respectively. There is no indication of causal associations between other circulating metabolites and the risk of VTE.

Conclusions: Genetically liability to low-serum albumin and total protein levels, low proxied monounsaturated fatty acids (MUFAs) and the ratio of MUFAs to total fatty acids are associated with the higher risk of VTE.

The Higher Prevalence of Venous Thromboembolism in the Hungarian Roma Population Could Be Due to Elevated Genetic Risk and Stronger Gene-Environmental Interactions

Background: Interactions between genetic and environmental risk factors (GxE) contribute to an increased risk of venous thromboembolism (VTE). Understanding how these factors interact provides insight for the early identification of at-risk groups within a population and creates an opportunity to apply appropriate preventive and curative measures.

Objective: To estimate and compare GxE for VTE risk in the general Hungarian and Roma populations.

Methods: The study was based on data extracted from a database consisting of results previously obtained from a complex health survey with three pillars (questionnaire-based, physical, and laboratory examinations) involving 406 general Hungarian and 395 Roma subjects. DNA was genotyped for rs121909567 (SERPINC1), rs1799963 (F2), rs2036914 (F11), rs2066865 (FGG), rs6025 (F5), and rs8176719 (ABO) polymorphisms. After allele frequency comparisons, the odds ratio (OR) was calculated for individual SNPs. Furthermore, genetic risk scores (weighted GRS, unweighted GRS) were computed to estimate the joint effect of the genetic factors. Multivariable linear regression analysis was applied to test the impact of GxE on VTE risk after interaction terms were created between genetic and VTE risk factors [diabetes mellitus (DM), cancer, chronic kidney diseases (CKD), coronary artery diseases (CAD), migraine, depression, obesity, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high density lipoprotein (HDL-C), triglyceride (TG), and smoking].

Results: Interestingly, the rs121909567 (SERPINC1, ATBp3 mutation) SNP was not present in the general population at all. However, the risk allele frequency was 1% among the Roma population, which might suggest a founder effect in this minority. This polymorphism multiplicatively interacted with CAD, CKD, cancer, DM, depression, migraine, and obesity. Even though interactions were not statistically significant, the trend of interaction showed the probability of an incremental VTE risk among the Roma population. The risk of VTE was 4.7 times higher (p > 0.05) for Roma subjects who had ≥3 wGRS (median value) compared with individuals having lower wGRS values but lower for the general subjects (OR = 3.1 × 10⁻⁸). Additionally, the risk of VTE was 6.6 times higher in the Roma population that had ≥3 risk alleles (median value) than in individuals with the 0–1 risk allele, and the overall risk was much higher for the Roma population (OR = 6.6; p > 0.05) than for the general Hungarian population (OR = 1.5; p > 0.05). Five positive and significant GxE interactions were identified in the Roma population. The risk of VTE was higher among depressive Roma subjects who carried the risk variant rs2036914 (β = 0.819, p = 0.02); however, this interaction was not significant for the general subjects. The joint presence of high levels of LDL-C and rs2066865 (FGG) increased the VTE risk only among Roma individuals (β = 0.389, p = 0.002). The possibility of VTE risk increment, as a result of a multiplicative interaction between rs8176719 (ABO) and cancer, was identified, which was higher for the Roma population (β = 0.370, p < 0.001) than for the general population (β = −0.042, p = 0.6). The VTE risk increased in the Roma population (β = 0.280, p = 0.001), but was higher in the general population (β = 0.423, p = 0.001) as a result of the multiplicative interaction between CAD and rs2036914 (F11). The presence of a multiplicative interaction between rs2066865 (FGG) and CAD increased the VTE risk for the Roma population (β = 0.143, p = 0.046) but not for the general population (β = −0.329, p < 0.001).

Conclusions: rs121909567 (SERPINC1, ATBp3) was confirmed as a founder mutation in the Roma population. Our study revealed some evidence on the burden of the joint presence of genetic and environmental risk factors on VTE, although the finding is highly subjected to the selection and observational biases due to the very small number of VTE cases and the observational nature of the study design, respectively. As a result of higher genetic load and GxE interactions, this minority Roma population is at higher risk of VTE than the general Hungarian population. Thus, our results suggest the need for an intensive search for the rs121909567 (SERPINC1; ATBp3) founder mutation, which might be an important factor for the assessment of thrombotic disease susceptibility among the Roma population. In addition, we strongly recommend further studies among a large number of VTE cases to explore the more precise impact of genetic and environmental risk factors on VTE in the study populations.

Emerging views of statin pleiotropy and cholesterol lowering

Over the past four decades, no class of drugs has had more impact on cardiovascular health than the HMC-CoA reductase inhibitors or statins. Developed as potent lipid-lowering agents, statins were later shown to reduce morbidity and mortality of patients who are at risk for cardiovascular disease. However, retrospective analyses of some of these clinical trials have uncovered some aspects of their clinical benefits that may be additional to their lipid-lowering effects. Such "pleiotropic" effects of statins garnered intense interest and debate over its contribution to cardiovascular risk reduction. This review will provide a brief background of statin pleiotropy, assess the available clinical evidence for and against their non-lipid-lowering benefits, and propose future research directions in this field.

Correlation between climatic and biochemical parameters in etiopathogenesis of unprovoked deep vein thrombosis of the lower limbs

AIM

Beside the intention of early detection and optimal treatment of deep venous thrombosis (DVT), the aim of this study was to investigate the influence of chronobiological rhythms on the etiopathogenesis of unprovoked deep vein thrombosis of the lower limbs with monitoring of seasonal variations in biochemical parameters.

PATIENTS AND METHODOLOGY

The prospective clinical trial included all consecutive hospitalized patients and outpatients diagnosed with DVT at the Vascular Surgery Clinic of the Clinical Center in Niš, starting from January 2013 to December 2014.

RESULTS

There was no statistically significant difference in correlation between the distribution of the incidence of DVT of the lower limbs (p = 0.582), sex (p = 0.350), age (p = 0.385) and localization (p = 0.886) and the seasons. Creatinine levels were significantly higher in patients who developed DVT in spring than in those who developed DVT in winter (p < 0.05), while LDL cholesterol levels were significantly higher in patients diagnosed with DVT in winter than in those diagnosed with DVT in autumn (p < 0.05).

CONCLUSION

According to the results of the study, it can be concluded that in the territory of South Serbia, the seasons are not significantly related to the incidence, sex, age and localization of unprovoked DVT of the lower limbs. Creatinine levels were significantly higher in patients who developed DVT in spring than in those who developed DVT in winter, while LDL cholesterol levels were significantly higher in patients during winter than during autumn.

Lifestyle Moderates Genetic Risk of Venous Thromboembolism: The ARIC Study

OBJECTIVE

Venous thromboembolism (VTE) is a common disease that has a genetic basis. Lifestyle factors contribute to risk, but it is unknown whether healthy lifestyle can mitigate the genetic risk. We studied whether greater adherence to the American Heart Association's cardiovascular health metric, Life's Simple 7 (LS7), is associated with lower incidence of VTE in individuals across categories of a genetic risk score (GRS) for VTE. Approach AND RESULTS: We followed 9026 White participants from the ARIC (Atherosclerosis Risk in Communities) Study, a prospective cohort enrolled in 1987 to 1989 until 2015. We tested the joint associations with VTE of a validated VTE GRS comprising 5 well-known gene variants and baseline LS7 categories. There were 466 incident VTE events over 22.8 years. Participants with an optimal LS7 score had a lower incidence of VTE (3.9%) than those with inadequate LS7 (5.7%). Compared with the high GRS and inadequate LS7 group (hazard ratio=1), those with high GRS and optimal LS7 indeed had a reduced hazard ratio of VTE: 0.65 (95% CI, 0.48-0.89). The group with low GRS and optimal LS7 had the lowest hazard ratio of VTE (0.39 [95% CI, 0.25-0.61]). Of the LS7 components, in all GRS groups, the factor most strongly protective for VTE was normal weight.

CONCLUSIONS

Among people at low or high genetic risk for VTE, healthier lifestyle factors, particularly normal weight, were associated with a lower incidence of VTE. Further studies should determine the impact of lifestyle changes among patients at high genetic risk of VTE, such as in thrombophilic families.

The Effect of PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) Inhibition on the Risk of Venous Thromboembolism

BACKGROUND

The relationship between cholesterol levels and risk of venous thromboembolism (VTE) is uncertain. We set out to determine the effect of PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibition on the risk of VTE, explore potential mechanisms, and examine the efficacy in subgroups with clinically and genetically defined risk.

METHODS

We performed a post hoc analysis of the FOURIER trial (Further Cardiovascular Outcomes Research With PCSK9 Inhibition in Subjects With Elevated Risk) testing whether evolocumab reduces the risk of VTE events (deep venous thrombosis or pulmonary embolism). Data from FOURIER and ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment with Alirocumab) were then combined in a meta-analysis to assess the class effect of PCSK9 inhibition on the risk of VTE. We also analyzed baseline lipids in FOURIER to investigate potential mechanisms explaining the reduction in VTE with evolocumab. Last, an exploratory genetic analysis was performed in FOURIER to determine whether a VTE polygenic risk score could identify high-risk patients who would derive the greatest VTE reduction from evolocumab.

RESULTS

In FOURIER, the hazard ratio (HR) for VTE with evolocumab was 0.71 (95% CI, 0.50-1.00; P=0.05), with no effect in the 1st year (HR, 0.96 [95% CI, 0.57-1.62]) but a 46% reduction (HR, 0.54 [95% CI, 0.33-0.88]; P=0.014) beyond 1 year. A meta-analysis of FOURIER and ODYSSEY OUTCOMES demonstrated a 31% relative risk reduction in VTE with PCSK9 inhibition (HR, 0.69 [95% CI, 0.53-0.90]; P=0.007). There was no relation between baseline low-density lipoprotein cholesterol levels and magnitude of VTE risk reduction. In contrast, in patients with higher baseline lipoprotein(a) (Lp[a]) levels, evolocumab reduced Lp(a) by 33 nmol/L and risk of VTE by 48% (HR, 0.52 [95% CI, 0.30-0.89]; P=0.017), whereas, in patients with lower baseline Lp(a) levels, evolocumab reduced Lp(a) by only 7 nmol/L and had no effect on VTE risk (Pinteraction 0.087 for HR; Pheterogeneity 0.037 for absolute risk reduction). Modeled as a continuous variable, there was a significant interaction between baseline Lp(a) concentration and magnitude of VTE risk reduction (Pinteraction=0.04). A polygenic risk score identified patients who were at >2-fold increased risk for VTE and who derived greater relative (Pinteraction=0.04) and absolute VTE reduction (Pheterogeneity=0.009) in comparison with those without high genetic risk.

CONCLUSIONS

PCSK9 inhibition significantly reduces the risk of VTE. Lp(a) reduction may be an important mediator of this effect, a finding of particular interest given the ongoing development of potent Lp(a) inhibitors.

Associations of Serum Lipids and Deep Venous Thrombosis Risk After Total Knee Arthroplasty in Patients With Primary Knee Osteoarthritis

Deep venous thrombosis (DVT) of the lower extremities is a common complication after total knee arthroplasty (TKA). This study aimed to investigate the potential associations between serum lipids and the risk of DVT after TKA in patients with primary knee osteoarthritis (OA). A total of 431 patients who received TKA caused by primary knee OA were randomly enrolled. According to the results of the color Doppler ultrasound of bilateral lower extremities deep veins on the third day postoperatively, patients were divided into DVT and non-DVT groups. Comparisons of preoperative serum levels of triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1, and apolipoprotein B were then performed by the Student’s t test, χ2 test, and multivariate logistic regression analysis. For females, DVT patients had a higher serum LDL-C level at baseline ( P = .043) compared with non-DVT patients. A higher LDL-C value was significantly associated with an elevated DVT risk following TKA in female patients ( P = .037). In female patients with primary knee OA, preoperative serum LDL-C level may have an association with DVT risk after TKA. The relatively small male sample size may limit the accuracy of the findings.

Association of apolipoproteins C-I, C-II, C-III and E with coagulation markers and venous thromboembolism risk

Purpose

Apolipoproteins C-I, C-II, C-III and E have been associated with risk of arterial thrombotic diseases. We investigated whether these apolipoproteins have prothrombotic properties and are associated with risk of venous thromboembolism (VTE).

Patients and methods

A total of 127 VTE patients and 299 controls were randomly selected from the Multiple Environmental and Genetic Assessment of Risk Factors for Venous Thrombosis study (1999–2004), in the Netherlands. The apolipoproteins were quantified using mass spectrometry (LC/MS/MS), and their levels were analyzed as continuous variable (per SD increase).

Results

In controls, increases in levels of apolipoproteins were associated with increases in levels of vitamin K-dependent factors, factor XI, antithrombin and clot lysis time. Additionally, increasing apolipoproteins C-III and E levels were associated with higher factor VIII and von Willebrand factor levels. Levels of C-reactive protein were not associated with any apolipoprotein. The age- and sex-adjusted odds ratios of apolipoproteins E, C-III, CII and CI to the risk of venous thrombosis were 1.21 (95% CI, 0.98–1.49), 1.19 (95% CI, 0.99–1.44), 1.24 (95% CI, 0.95–1.61) and 1.06 (95% CI, 0.87–1.30) per SD increase, respectively. These odds ratios did not attenuate after adjustments for statin use, estrogen use, BMI, alcohol use, and self-reported diabetes.

Conclusions

Levels of apolipoproteins C-I, C-II, C-III and E are associated with those of several coagulation factors. However, whether these apolipoproteins are also associated with an increased risk of VTE remains to be established.

Lipoprotein(a) is not associated with venous thromboembolism risk

Objectives. Evidence from case-control studies as well as meta-analyses of these study designs suggest elevated lipoprotein(a) [Lp(a)] to be associated with an increased risk of venous thromboembolism (VTE). Prospective evidence on the association is limited, uncertain, and could be attributed to regression dilution bias. We aimed to assess the prospective association of Lp(a) with risk of VTE and correct for regression dilution. Design. We related plasma Lp(a) concentrations to the incidence of VTE in 2,180 men of the Kuopio Ischemic Heart Disease cohort study. Hazard ratios (HRs) (95% confidence intervals [CI]) were assessed and repeat measurements of Lp(a) at 4 and 11 years from baseline, were used to correct for within-person variability. Results. After a median follow-up of 24.9 years, 110 validated VTE cases were recorded. The regression dilution ratio of log_e Lp(a) adjusted for age was 0.85 (95% CI: 0.82-0.89). In analyses adjusted for several established risk factors and potential confounders, the HR (95% CI) for VTE per 1 SD (equivalent to 3.56-fold) higher baseline log_e Lp(a) was 1.06 (0.87-1.30). In pooled analysis of five population-based cohort studies (including the current study) comprising 66,583 participants and 1314 VTE cases, the fully-adjusted corresponding HR for VTE was 1.00 (95% CI: 0.94-1.07), with no evidence of heterogeneity between studies. Conclusions. Primary analysis as well as pooled evidence from previous studies suggest circulating Lp(a) is not prospectively associated with future VTE risk, indicating that evidence of associations demonstrated in case-control designs may be driven by biases such as selection bias.

Oxidized low-density lipoprotein in inflammation-driven thrombosis

Thrombosis is the defining feature of the most prevalent causes of cardiovascular mortality, such as myocardial infarction, stroke, and pulmonary artery embolism. Although platelet activation and activation of the plasmatic coagulation system are the hallmarks of thrombus formation, inflammatory processes and the cellular responses involved are increasingly being recognized as critical modulators of thrombosis. In the context of many chronic inflammatory diseases that are associated with a high thrombotic risk, oxidized lipoproteins represent a prominent sterile trigger of inflammation. Oxidized low-density lipoprotein and its components play a central role in the initiation and progression of atherosclerotic plaques, but also in other processes that lead to thrombotic events. Moreover, dying cells and microvesicles can be decorated with some of the same oxidized lipid components that are found on oxidized lipoproteins, and thereby similar mechanisms of thromboinflammation may also be active in venous thrombosis. In this review, we summarize the current knowledge on how oxidized lipoproteins and components thereof affect the cells and pathways involved in thrombosis.

Thrombosis in central obesity and metabolic syndrome: Mechanisms and epidemiology

Central obesity is a key feature of the metabolic syndrome (metS), a multiplex risk factor for subsequent development of type 2 diabetes and cardiovascular disease. Many metabolic alterations closely related to this condition exert effects on platelets and vascular cells. A procoagulant and hypofibrinolytic state has been identified, mainly underlain by inflammation, oxidative stress, dyslipidaemia, and ectopic fat that accompany central obesity. In support of these data, central obesity independently predisposes not only to atherothrombosis but also to venous thrombosis.

Lipid levels and risk of venous thrombosis: results from the MEGA-study

The relationship between lipid levels and risk of venous thrombosis is not well established. We aimed to assess the association between several lipids and risk of venous thrombosis using data from a population-based case-control study, and to evaluate the underlying mechanism, considering confounding by common risk factors and mediation via hemostatic factors and C-reactive protein. From the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) study, 2234 patients with a first venous thrombosis and 2873 controls were included. Percentile categories of total/low-density lipoprotein/high-density lipoprotein cholesterol, triglycerides, and apolipoproteins B and A1 were established in controls (<10th, 10th-25th, 25th-75th [reference], 75th-90th, >90th percentile). In age- and sex-adjusted models, decreasing levels of apolipoproteins B and A1 were dose-dependently associated with increased thrombosis risk, with odds ratios of 1.35 (95% confidence interval 1.12-1.62) and 1.50 (95% confidence interval 1.25-1.79) for the lowest category versus the reference category, respectively. The dose-response relation remained with further adjustment for body mass index, estrogen use, statin use, and diabetes. Although apolipoproteins B and A1 were associated with several hemostatic factors and C-reactive protein, none explained the increased risk in mediation analyses. The other lipids were not associated with venous thrombosis risk. In conclusion, decreasing levels of apolipoproteins B and A1 were associated with increased risk of venous thrombosis. Our findings are consistent with experimental data on the anticoagulant properties of apolipoproteins B and A1. These findings need to be confirmed and the underlying mechanism further investigated.

Lipid levels and risk of recurrent venous thrombosis: results from the MEGA follow-up study

Essentials The role of lipid levels in the risk of recurrent venous thrombosis is unclear. Lipids were assessed in patients with a first venous thrombosis (n = 2106) followed for 6.9 years. Lipids were not associated with recurrence, overall or in patients with unprovoked first events. Testing lipid levels is not useful to identify patients at an increased risk of recurrence.

SUMMARY

Background Knowledge of risk factors for recurrent venous thrombosis may guide decisions on duration of anticoagulation. The association between lipid levels and first venous thrombosis has been studied extensively. However, data on the role of lipids in the risk of recurrence are scarce. Objective To assess the association between lipid levels and recurrent venous thrombosis. Patients/Methods Patients with a first venous thrombosis from the MEGA study were included. Follow-up started at the date of end of anticoagulant treatment. Percentile categories of total/low-density lipoprotein/high-density lipoprotein cholesterol, triglycerides and apolipoproteins B and A1 were established (< 10th, 10th-25th, 25th-75th [reference], 75th-90th, > 90th percentile). Lipids were measured at least 3 months after discontinuing anticoagulation. Results Of 2106 patients followed for a median of 6.9 years, 326 developed recurrence (incidence rate, 2.7/100 patient-years; 95% confidence interval [CI], 2.5-3.1). With hazard ratios ranging from 0.88 (95% CI, 0.55-1.42) to 1.33 (95% CI, 0.86-2.04) in the highest percentile category vs. the reference, we found no association across percentile categories between recurrence and lipid levels in age- and sex-adjusted models, nor after further adjustments for body mass index, diabetes, estrogen and statin use, and duration of anticoagulation. Subgroup analyses stratified by unprovoked or provoked first events, location (deep vein thrombosis or pulmonary embolism) and sex also did not reveal an association with any of the lipid levels studied. Conclusions Testing lipid levels did not identify patients at an increased risk of recurrent venous thrombosis in this study, including those with unprovoked first events, and these should not influence decisions on duration of anticoagulation.

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.

Lipoprotein (a): truly a direct prothrombotic factor in cardiovascular disease?

Elevated plasma concentrations of lipoprotein (a) [Lp(a)] have been determined to be a causal risk factor for coronary heart disease, and may similarly play a role in other atherothrombotic disorders. Lp(a) consists of a lipoprotein moiety indistinguishable from LDL, as well as the plasminogen-related glycoprotein, apo(a). Therefore, the pathogenic role for Lp(a) has traditionally been considered to reflect a dual function of its similarity to LDL, causing atherosclerosis, and its similarity to plasminogen, causing thrombosis through inhibition of fibrinolysis. This postulate remains highly speculative, however, because it has been difficult to separate the prothrombotic/antifibrinolytic functions of Lp(a) from its proatherosclerotic functions. This review surveys the current landscape surrounding these issues: the biochemical basis for procoagulant and antifibrinolytic effects of Lp(a) is summarized and the evidence addressing the role of Lp(a) in both arterial and venous thrombosis is discussed. While elevated Lp(a) appears to be primarily predisposing to thrombotic events in the arterial tree, the fact that most of these are precipitated by underlying atherosclerosis continues to confound our understanding of the true pathogenic roles of Lp(a) and, therefore, the most appropriate therapeutic target through which to mitigate the harmful effects of this lipoprotein.

Predictive value of HDL cholesterol for cancer-associated venous thromboembolism during chemotherapy

BACKGROUND

Dyslipidemia is a well-known risk factor for the development of atherothrombosis; however, its involvement in venous thromboembolism (VTE) is still debated. Low levels of HDL cholesterol (HDL-C) have been found to be associated with VTE, which is a common complication of cancer and its treatment. VTE incidence is increased in cancer patients, especially those undergoing chemotherapy.

OBJECTIVE

We sought to investigate the value of pretreatment HDL-C in the risk prediction of future VTE in a population of ambulatory cancer patients undergoing chemotherapy.

PATIENTS AND METHODS

Blood lipid composition was retrospectively evaluated in 592 consecutive patients with primary (n = 373) or relapsing/recurrent (n = 219) solid cancers at the start of a new chemotherapy regimen (12% neoadjuvant, 31% adjuvant, 57% metastatic).

RESULTS

VTE occurred during chemotherapy in 38 patients (median time-to-event: 3 months). Mean HDL-C levels were lower in patients who developed VTE during chemotherapy (41 mg dL(-1) ; standard deviation [SD] 13 mg dL(-1) ) than in those who did not (48 mg dL(-1) ; SD 14 mg dL(-1) ). Cox proportional hazard survival analysis showed that HDL-C levels ≤ 43 mg dL(-1) were able to significantly predict a first VTE episode, with a hazard ratio of 2.87 (95% confidence interval 1.45-5.68). Moreover, patients with HDL-C levels ≤ 43 mg dL(-1) had worse 1-year VTE-free survival (86%) than those with HDL-C levels > 43 mg dL(-1) (96%; log rank test, 3.14).

CONCLUSIONS

Patients with low HDL-C levels have a three-fold higher risk of developing a first VTE episode during chemotherapy. Baseline analysis of HDL-C levels might be of clinical value in predicting VTE in cancer outpatients treated with anticancer drugs.

Severe hypertriglyceridaemia during therapy for childhood acute lymphoblastic leukaemia

BACKGROUND

Asparaginase and steroids can cause hypertriglyceridaemia in children with acute lymphoblastic leukaemia (ALL). There are no guidelines for screening or management of patients with severe hypertriglyceridaemia (>1000mg/dL) during ALL therapy.

PATIENTS AND METHODS

Fasting lipid profiles were obtained prospectively at four time-points for 257 children consecutively enrolled on a frontline ALL study. Risk factors were evaluated by the exact chi-square test. Details of adverse events and management of hypertriglyceridaemia were extracted retrospectively.

RESULTS

Eighteen of 257 (7%) patients developed severe hypertriglyceridaemia. Older age and treatment with higher doses of asparaginase and steroids on the standard/high-risk arm were significant risk factors. Severe hypertriglyceridaemia was not associated with pancreatitis after adjustment for age and treatment arm or with osteonecrosis after adjustment for age. However, patients with severe hypertriglyceridaemia had a 2.5-3 times higher risk of thrombosis compared to patients without, albeit the difference was not statistically significant. Of the 30 episodes of severe hypertriglyceridaemia in 18 patients, seven were managed conservatively while the others with pharmacotherapy. Seventeen of 18 patients continued to receive asparaginase and steroids. Triglyceride levels normalised after completion of ALL therapy in all 12 patients with available measurements.

CONCLUSION

Asparaginase- and steroid-induced transient hypertriglyceridaemia can be adequately managed with dietary modifications and close monitoring without altering chemotherapy. Patients with severe hypertriglyceridaemia were not at increased risk of adverse events, with a possible exception of thrombosis. The benefit of pharmacotherapy in decreasing symptoms and potential complications requires further investigation.

Budd-Chiari Syndrome with Multiple Thrombi due to a Familial Arg42Ser Mutation in the Protein C Gene

A 34-year-old Japanese woman was admitted to our hospital complaining of developing bilateral pedal edema. Imaging studies led to a diagnosis of Budd-Chiari syndrome combined with internal jugular vein thrombus. We investigated the cause of thrombosis and found that the anticoagulant activity of protein C was decreased. Genetic analysis showed the presence of a c.125C>A (Arg42Ser) substitution in the protein C gene (PROC) of the proband, which generates an Arg42Ser mutation that replaces the scissile bond Arg42-Ala43 normally cleaved by a furin-like processing protease. Her father and younger brother also carried this mutation, although they had no evidence of thrombosis.