Dynamic and functional linkage between von Willebrand factor and ADAMTS-13 with aging: an Atherosclerosis Risk in Community study

BACKGROUND

von Willebrand factor (VWF) is a multimeric glycoprotein critically involved in hemostasis, thrombosis, and inflammation. VWF function is regulated by its antigen levels, multimeric structures, and the state of enzymatic cleavage. Population studies in the past have focused almost exclusively on VWF antigen levels in cross-sectional study designs.

OBJECTIVE

To identify subjects in the Atherosclerosis Risk in Community study who had persistently low and high VWF antigen over 10 years and to quantify longitudinal changes in the biological activities and cleavage of VWF in these subjects.

METHODS

We measured VWF antigen, propeptide, adhesive activities, and cleavage by ADAMTS-13 quantified using a mass spectrometry method that detected the cleaved VWF peptide EQAPNLVY, as well as coagulation factor VIII activity.

RESULTS

We determined the mean subject-specific increase in VWF to be 22.0 International Units (IU)/dL over 10 years, with 95% between -0.3 and 59.7 IU/dL. This aging-related increase was also detected in VWF propeptide levels, ristocetin cofactor activity, and VWF binding to collagen. We identified 4.1% and 25.0% of subjects as having persistently low (<50 IU/dL) and high (>200 IU/dL) VWF antigen, respectively. Subjects with persistently low VWF had enhanced ristocetin cofactor activity, whereas those with persistently high VWF had elevated levels of ADAMTS-13, resulting in a comparable rate of VWF cleavage between the 2 groups.

CONCLUSIONS

These results provide new information about the effects of aging on VWF antigens and adhesive activity and identify a functional coordination between VWF and the rate of its cleavage by ADAMTS-13.

Relationship between serum homocysteine, fibrinogen, lipoprotein-a level, and peripheral arterial disease: a dose-response meta-analysis

AIM

At present, the relationship between serum homocysteine (Hcy), fibrinogen (FIB), lipoprotein-a (LPa), and PAD is uncertain, and there has been no meta-analysis to establish the dose-response relationship between their exposure levels and PAD.

METHODS AND RESULTS

Relevant literature published in PubMed, Embase, and Web of Science was retrieved. The robust error meta-regression method was used to assess the linear and non-linear dose-response relationship between exposure level and PAD risk. A total of 68 articles, involving 565,209 participants, were included. Combined with continuous variables, the serum Hcy, FIB, and LPa levels of PAD patients were significantly higher than those of healthy individuals. The odds ratios (ORs) of PAD for individuals with high Hcy, FIB, and LPa levels compared with those with low levels were 1.47, 1.14, and 1.76, respectively. The study also showed that circulating Hcy, FIB, and LPa were significantly elevated in patients with PAD compared with controls. The level of Hcy and the risk of PAD presented a U-shaped distribution. The nonlinear dose-response model showed that each 1 μmol/L increase in serum Hcy increased the risk of PAD by 7%. Similarly, for each 10 mg/dL FIB and 10 mg/dL LPa increases, the risk of PAD increased by 3% and 6%, respectively.

CONCLUSIONS

This meta-analysis provided evidence that elevated Hcy, PIB, and LPa levels may increase the risk of PAD, and the risk of PAD increases with the increase in serum exposure within a certain range. By controlling Hcy level, the incidence of PAD may be reduced to control the PAD growing epidemic.

TRIAL REGISTRATION NUMBER

PROSPERO (CRD42021250501), https://www.crd.york.ac.uk/prospero/.

Mendelian Randomization Analysis of Hemostatic Factors and Their Contribution to Peripheral Artery Disease-Brief Report

BACKGROUND AND OBJECTIVE

Peripheral artery disease (PAD) is the third most common form of atherosclerotic vascular disease and is characterized by significant functional disability and increased cardiovascular mortality. Recent genetic data support a role for a procoagulation protein variant, the factor V Leiden mutation, in PAD. The role of other hemostatic factors in PAD remains unknown. We evaluated the role of hemostatic factors in PAD using Mendelian randomization. Approach and Results: Two-sample Mendelian randomization to evaluate the roles of FVII (factor VII), FVIII (factor VIII), FXI (factor XI), VWF (von Willebrand factor), and fibrinogen in PAD was performed using summary statistics from GWAS for hemostatic factors performed within the Cohorts for Heart and Aging Research in the Genome Epidemiology Consortium and from GWAS performed for PAD within the Million Veteran Program. Genetically determined FVIII and VWF, but not FVII, FXI, or fibrinogen, were associated with PAD in Mendelian randomization experiments (FVIII: odds ratio, 1.41 [95% CI, 1.23-1.62], P=6.0×10^-7, VWF: odds ratio, 1.28 [95% CI, 1.07-1.52], P=0.0073). In single variant sensitivity analysis, the ABO locus was the strongest genetic instrument for both FVIII and VWF.

CONCLUSIONS

Our results suggest a role for hemostasis, and by extension, thrombosis in PAD. Further study is warranted to determine whether VWF and FVIII independently affect the biology of PAD.

Tissue-type plasminogen activator and plasminogen activator inhibitor type 1 in patients with symptomatic lower extremity artery disease

BACKGROUND

Lower extremity artery disease (LEAD) involves progressive arterial narrowing manifested by intermittent claudication (IC). LEAD entails endothelial dysfunction and fibrinolytic disorders. In the current study, we analyze the selected parameters of the fibrinolytic system in the blood of patients with symptomatic LEAD depending on clinical parameters.

METHODS

The test group was comprised of 80 patients with diagnosis of LEAD based on Ankle-Brachial Index (ABI) test (27 female/53 male) with an average age of 63.5±9 years. The control group included 30 healthy, non-smoking volunteers (10 female/20 male), with the median age of 56±6 years. The research material - venous blood - was sampled to determine the concentrations of tissue-type plasminogen activator (t-PA Ag), plasminogen activator inhibitor type 1 (PAI-1 Ag), D-dimer, fibrinogen, and platelet count (PLT).

RESULTS

We found elevated concentrations of t-PA Ag, PAI-1 Ag, D-dimer, and fibrinogen in the plasma of subjects with symptomatic LEAD. Various stages of the Fontaine classification demonstrated a gradual, statistically significant increase in the concentrations of fibrinogen and PLT count as the disease progressed. More so, in the subgroup of LEAD patients aged ≥65 years, we observed significantly higher levels of D-dimer than in the group of younger subjects. In addition to that, the LEAD group demonstrated negative correlations of IC distance, fibrinogen concentrations, and PLT count, negative correlations of ABI at rest and concentrations of D-dimer and PLT count, as well as positive correlations between age and D-dimer levels.

CONCLUSIONS

High t-PA Ag concentrations in LEAD patients suggest damage to the endothelium which comprises the main source of this factor. With high PAI-1 Ag levels, inactive fibrinolytic t-PA-PAI-1 complexes are formed. Increasing fibrinogen concentrations at the subsequent stages in accordance with the Fontaine classification, indicate increasing inflammation. Moreover, heightened values of D-dimer reflect an increased secondary fibrinolysis activation as patients get older and impaired extremity vascularization, manifested by the decreasing ABI, progresses.

The White Blood Cell Count to Mean Platelet Volume Ratio for the Prediction of Chronic Limb-Threatening Ischemia in Lower Extremity Artery Disease

Background: The white blood cell count to mean platelet volume ratio (WMR) is increasingly gaining importance as a promising prognostic marker in atherosclerotic disease, but data on lower extremity artery disease (LEAD) are not yet available. The principle aim of this study was to assess the association of the WMR with the occurrence of CLTI (chronic limb-threatening ischemia) as the most advanced stage of disease. Methods: This study was performed as a retrospective analysis on 2121 patients with a diagnosis of LEAD. Patients were admitted to the hospital for the reason of LEAD and received conservative or endovascular treatment. Blood sampling, in order to obtain the required values for this analysis, was implemented at admission. Statistical analysis was conducted by univariate regression in a first step and, in case of significance, by multivariate regression additionally. Results: Multivariate regression revealed an increased WMR (p < 0.001, OR (95%CI) 2.258 (1.460–3.492)), but also advanced age (p < 0.001, OR (95%CI) 1.050 (1.040–1.061)), increased CRP (p < 0.001, OR (95%CI) 1.010 (1.007–1.014)), and diabetes (p < 0.001, OR (95%CI) 2.386 (1.933–2.946)) as independent predictors for CLTI. Conclusions: The WMR presents an easily obtainable and cost-effective parameter to identify LEAD patients at high risk for CLTI.

Coagulation disorders and their cutaneous presentations: Pathophysiology

Hypercoagulable states are inherited or acquired predispositions to venous or arterial thromboses that are best understood in the context of the coagulation cascade. Dermatologists can play a critical role in diagnosing and treating patients with hypercoagulable states because cutaneous symptoms may be a presenting manifestation, thereby reducing morbidity and mortality related to these conditions. This review focuses on the epidemiology and pathophysiology of hypercoagulable states, while the accompanying article iterates the basic clinical features, diagnostic testing, and management of patients who have these conditions.

Estudo comparativo do Índice Tornozelo-Braquial em diabéticos e não diabéticos com isquemia crítica

Resumo Contexto A calcificação da camada média arterial pode tornar o Índice Tornozelo-Braquial (ITB) falsamente elevado em diabéticos, dificultando a avaliação da doença arterial. Objetivo Comparar os valores do ITB de diabéticos e não diabéticos com isquemia crítica. Métodos Foram incluídos 140 pacientes (60% de diabéticos) acompanhados no Serviço de Cirurgia Vascular do Complexo Hospitalar Universitário Professor Edgard Santos com isquemia crítica por DAOP infra-inguinal. Comparou-se a média dos valores do ITB dos dois grupos de pacientes, correlacionando o ITB com a gravidade da isquemia, segundo a Classificação de Rutherford. A análise estatística foi realizada pelo EPI-INFO. Resultados A maioria dos 140 pacientes (77%) se encontrava na Categoria 5 da Classificação de Rutherford, 6% na 4 e 17% na 6. Nove diabéticos (11%) e um não diabético (2%) apresentaram ITB > 1,15 (p = 0,02), sendo excluídos da análise das médias do ITB. Considerando os 130 pacientes, os 75 doentes diabéticos apresentaram média do ITB na artéria tibial posterior de 0,26 versus 0,28 dos 55 doentes não diabéticos (p = 0,6); e no ITB da artéria pediosa aqueles apresentaram média de 0,32 versus 0,23 desses (p = 0,06). Estratificando os doentes nas categorias da Classificação de Rutherford, não houve diferença nas médias do ITB nas categorias 4 e 5. Apenas em relação à artéria pediosa e em pacientes na Categoria 6, a média do ITB foi significativamente maior em diabéticos (0,44 versus 0,16; p = 0,03). Conclusão Os diabéticos apresentaram maior prevalência de ITB falsamente elevado. Porém, excluindo-se esses casos, a média dos valores de ITB são semelhantes aos não diabéticos, exceto na artéria pediosa, nos pacientes com isquemia na categoria 6.

Distribution, genetic and cardiovascular determinants of FVIII:c - Data from the population-based Gutenberg Health Study

BACKGROUND

Elevated levels of

FVIII

c are associated with risk for both venous and arterial thromboembolism. However, no population-based study on the sex-specific distribution and reference ranges of plasma

FVIII

c and its cardiovascular determinants is available.

METHODS

FVIII

c was analyzed in a randomly selected sample of 2533 males and 2440 females from the Gutenberg Health Study in Germany. Multivariable regression analyses for

FVIII

c were performed under adjustment for genetic determinants, cardiovascular risk factors and cardiovascular disease.

RESULTS AND CONCLUSIONS

Females (126.6% (95% CI: 125.2/128)) showed higher

FVIII

c levels than males (121.2% (119.8/122.7)).

FVIII

c levels increased with age in both sexes (ß per decade: 5.67% (4.22/7.13) male, 6.15% (4.72/7.57) female; p<0.001). Sex-specific reference limits and categories indicating the grade of deviation from the reference were calculated, and nomograms for

FVIII

c were created.

FVIII

c was approximately 25% higher in individuals with non-O blood type. Adjusted for sex and age, ABO-blood group accounted for 18.3% of

FVIII

c variation. In multivariable analysis,

FVIII

c was notably positively associated with diabetes mellitus, obesity, hypertension and dyslipidemia and negatively with current smoking. In a fully adjusted multivariable model, the strongest associations observed were of elevated

FVIII

c with diabetes and peripheral artery disease in both sexes and with obesity in males. Effects of SNPs in the vWF, STAB2 and SCARA5 gene were stronger in females than in males. The use of nomograms for valuation of

FVIII

c might be useful to identify high-risk cohorts for thromboembolism. Additionally, the prospective evaluation of

FVIII

c as a risk predictor becomes feasible.

Association of total white cell count with mortality and major adverse events in patients with peripheral arterial disease: a systematic review

OBJECTIVES

Peripheral arterial disease (PAD) is principally caused by atherosclerosis, an established inflammatory disease. Total white cell count (TWCC) is a marker of inflammation and has been associated with outcomes for patients with inflammatory diseases. The aim of this systematic review was to assess the association of TWCC with mortality and major adverse events (MAEs) in PAD patients.

METHODS

Studies investigating the association of TWCC with outcome in patients with PAD were identified by a literature search using the Medline and Cochrane databases. To be eligible for inclusion, studies needed to investigate the association of TWCC with mortality or a composite endpoint that included mortality in patients with PAD. Studies were excluded when the primary focus was carotid artery disease, aortic aneurysmal disease, intracranial vascular disease, or rheumatoid arthritis and treatment with chemotherapy or transplantation of stem cells. Secondary searching of reference lists and relevant reviews was performed.

RESULTS

Ten studies including 8,490 patients with PAD met the inclusion criteria. All studies investigated more than 100 patients with four studies assessing more than 1,000 patients. Study quality varied with well-established risk factors of outcome such as age, smoking, diabetes, and the ankle brachial index being adjusted for inconsistently. The study populations were also disparate. Few studies reported relative risk and 95% confidence intervals for the association of TWCC with mortality or MAE. TWCC was positively and significantly associated with death alone in four of five studies investigating 3,387 patients. TWCC was positively and significantly associated with MAE in five of six studies investigating a total of 6,846 patients.

CONCLUSIONS

Current evidence suggests a positive association of TWCC with mortality and MAEs in patients with PAD. Further well-designed prospective studies are required with high-quality analysis and more complete reporting of outcomes.

Etiopathogenic Differences in Coronary Artery Disease and Peripheral Artery Disease

Cross-sectional data from the National Health and Nutrition Examination Surveys 1999 to 2004 were pooled for this study. Compared with coronary artery disease (CAD), a greater proportion of individuals with peripheral artery disease (PAD) were female, black, and active smokers. Patients with PAD had significantly higher serum concentrations of low-density lipoprotein cholesterol and C-reactive protein than those with CAD alone. The risk of CAD increased with serum cotinine levels >0.02 ng/mL. However, the risk of PAD increased only with serum cotinine levels >138 ng/mL. Despite this association, there was no significant association of secondhand smoke exposure with CAD or PAD. In conclusion, patients with CAD and PAD differed with respect to several demographic and biochemical factors. The relationship between PAD and cotinine demonstrated a threshold phenomenon (serum cotinine levels >138 ng/mL).

Ethnic differences in ankle brachial index are present in middle-aged individuals without peripheral arterial disease

INTRODUCTION

To better understand the basis for previously reported ethnic differences in ankle brachial index (ABI), we investigated whether these differences were present in individuals without known peripheral arterial disease (PAD).

METHODS

We used data from National Health and Nutrition Examination surveys (NHANES 1999-2004) to determine whether ethnic differences were present in respondents without PAD (1 ≤ ABI ≤ 1.3). We assessed whether ethnicity was an independent predictor of ABI and ankle systolic blood pressure (SBP) in linear regression models that adjusted for conventional and novel cardiovascular risk factors. To minimize effects of atherosclerosis on ABI, we studied adults aged ≤ 60 years, and also repeated our analyses in a subset aged ≤ 50 years that did not have risk factors for PAD.

RESULTS

3348 participants aged ≤ 60 years were included in the study. Mean ABI was 1.11 in non-Hispanic Blacks (NHB) and 1.13 in non-Hispanic Whites (NHW) (P < 0.0001). In multivariable linear regression analysis that adjusted for age, gender, ethnicity, smoking, height, diabetes, brachial SBP, dyslipidemia, diabetes, renal function, concurrent cardiovascular disease, and plasma levels of homocysteine, fibrinogen and C-reactive protein, NHB had lower ABI than NHW (β = -0.03 ± 0.004, P < 0.00001). Although, NHBs had higher ankle SBP than NHWs (by 5.4 mm Hg), NHBs had a lower mean ankle SBP (β = -3.663 mm Hg ± 0.500, P < 0.0001) after adjusting for clinical covariates, including brachial SBP, in multivariable analysis.

CONCLUSION

Ethnic differences in ABI are present in middle-aged adults at low risk for peripheral atherosclerosis.

Novel risk factors and the prediction of type 2 diabetes in the Atherosclerosis Risk in Communities (ARIC) study

OBJECTIVE

The objective of this study was to determine potential added value of novel risk factors in predicting the development of type 2 diabetes beyond that provided by standard clinical risk factors.

RESEARCH DESIGN AND METHODS

The Atherosclerosis Risk in Communities (ARIC) Study is a population-based prospective cohort study in four U.S. communities. Novel risk factors were either measured in the full cohort or in a case-control sample nested within the cohort. We started with a basic prediction model, previously validated in ARIC, and evaluated 35 novel risk factors by adding them independently to the basic model. The area under the curve (AUC), net reclassification index (NRI), and integrated discrimination index (IDI) were calculated to determine if each of the novel risk factors improved risk prediction.

RESULTS

There were 1,457 incident cases of diabetes with a mean of >7.6 years of follow-up among 12,277 participants at risk. None of the novel risk factors significantly improved the AUC. Forced expiratory volume in 1 s was the only novel risk factor that resulted in a significant NRI (0.54%; 95% CI: 0.33-0.86%). Adiponectin, leptin, γ-glutamyl transferase, ferritin, intercellular adhesion molecule 1, complement C3, white blood cell count, albumin, activated partial thromboplastin time, factor VIII, magnesium, hip circumference, heart rate, and a genetic risk score each significantly improved the IDI, but net changes were small.

CONCLUSIONS

Evaluation of a large panel of novel risk factors for type 2 diabetes indicated only small improvements in risk prediction, which are unlikely to meaningfully alter clinical risk reclassification or discrimination strategies.

The association between the metabolic syndrome and peripheral, but not coronary, artery disease is partly mediated by endothelial dysfunction: the CODAM study

BACKGROUND

The metabolic syndrome is associated with coronary artery disease (CAD) and with peripheral artery disease (PAD), but the underlying mechanisms explaining these associations have not yet been completely clarified. The aim was to investigate (i) whether endothelial dysfunction can explain the association between the metabolic syndrome and CAD and/or the severity of PAD, as measured by the ankle-arm index (AAIx); and (ii) whether any such mediation is independent of that from low-grade inflammation.

MATERIALS AND METHODS

We studied 539 subjects (232 men) aged 59·4 ± 6·9 years, with an increased risk of type 2 diabetes and cardiovascular diseases. Endothelial dysfunction and inflammation scores were calculated from three markers of endothelial dysfunction (soluble E-selectin, soluble vascular cell adhesion molecule-1 and von Willebrand factor) and six of inflammation (C-reactive protein, interleukin 6, soluble intercellular adhesion molecule-1, serum amyloid A, ceruloplasmin and haptoglobin). The association between the metabolic syndrome and CAD and/or PAD, and the mediating role of endothelial dysfunction herein was examined with logistic and linear regression analyses, all adjusted for age, sex and smoking.

RESULTS

Subjects with the metabolic syndrome (n = 289; 54%) had higher prevalence of CAD [OR (95%CI) = 1·75 (1·14; 2·69)] and lower AAIx [β (95% CI) = -0·036 (-0·056; -0·016)]. Endothelial dysfunction explained 6% of the association between the metabolic syndrome and CAD, and 19% of the association with AAIx, whereas low-grade inflammation explained 26% and 28% of these associations, respectively. Together, the two scores explained 24% and 36% of the association between the metabolic syndrome and CAD and AAIx, respectively.

CONCLUSIONS

Endothelial dysfunction explains part of the association between the metabolic syndrome and the severity of PAD, but is not involved in the association between the metabolic syndrome and CAD. This indicates that the pathophysiologies of coronary and peripheral artery disease are essentially distinct.

High thrombin activatable fibrinolysis inhibitor levels are associated with an increased risk of premature peripheral arterial disease

BACKGROUND

Previous studies suggested that hypofibrinolysis is associated with increased risk of peripheral arterial disease. Thrombin activatable fibrinolysis inhibitor (TAFI) has been identified as an important inhibitor of fibrinolysis. The aim of our study was to assess the role of TAFI in young patients with peripheral arterial disease.

METHODS

In a single-center case-control study we measured plasma TAFI antigen levels and functional TAFI in consecutive young patients (men 18-45 years and women 18-55 years) with a first manifestation of peripheral arterial disease and compared these with a population-based control group.

RESULTS

A total of 47 peripheral arterial disease patients and 141 controls (mean age 43) were included. Intact TAFI antigen levels were significantly higher in patients with peripheral arterial disease (112.4±21.1%) than in controls (104.9±19.9%, p=0.03). The risk of peripheral arterial disease increased with 18% (OR 1.18; CI 1.01-1.34) per 10% increase of TAFI antigen. Functional TAFI levels were slightly higher in patients compared to controls, however this difference was not significant. For individuals with the highest functional TAFI levels, above the 90th percentile, the increased risk for peripheral arterial disease was most pronounced (OR 3.1; CI 1.02-9.41).

CONCLUSION

High TAFI levels are associated with increased risk of premature peripheral arterial disease.

Study on Unrecognized Peripheral Arterial Disease (PAD) by Ankle/Brachial Index and Arterial Comorbidity in Catania, Sicily, Italy

Peripheral arterial disease (PAD) is under diagnosed and early diagnosis decreases consequences. We screened unrecognized PAD focusing on arterial co-morbidities. In the 3412 subjects, screened from 10 general practices in the city of Catania (Sicily, Italy), ankle brachial index (ABI) measurements were performed. An ABI ≤0.9 was considered as valid in diagnosing PAD. ABI value ≤0.9 was found in 2.3%, and a significant rate of carotid stenosis was also found Echocardiographic markers left ventricular diameter (LVD) >55 mm, interventricular septum (IVS) >11 mm, left ventricular diastolic volume (LVDV) was found > 100 ml), and ejection fraction (EF) was <50% were found with high frequency in those with ABI ≤0.9. Unrecognized PAD is lower compared with other findings but our prevalence resulted higher than other prevalence previously found by other study performed in Italy. Unrecognized PAD shows significant arterial co-morbidities and the ABI is a useful method to screen asymptomatic PAD.

The Association Between Ankle-Brachial Index and Quality of Life in Chronic Hemodialysis Patients

Ankle-brachial index (ABI) is an important indicator of peripheral arterial disease (PAD) and PAD has a negative impact on quality of life (QOL). However, the correlation between ABI and QOL is unknown among chronic hemodialysis patients. Ankle-brachial index was measured, and WHOQOL-BRIEF (TW) questionnaire was completed. The association between ABI and QOL was analyzed using linear regression. A total of 54 chronic hemodialysis patients (mean age of 56.2 ± 14.6 years) were included. Ankle-brachial index was positively associated with QOL (r = .448, P = .001). The QOL scores were 3.1 ± 2.9 and 2.6 ± 0.4 for 37 patients with an ABI more than 0.9 and 17 patients with an ABI less than 0.9 or more than 1.3 (p < .001). In linear regression, only ABI was significantly associated with QOL scores with a β of .448 (95% CI: 0.443 to 1.55, P = .001). Ankle-brachial index is positively correlated to QOL among chronic hemodialysis patients.

Novel markers of peripheral arterial disease

Peripheral arterial disease (PAD), a relatively common manifestation of atherosclerotic vascular disease, is associated with significant morbidity and mortality. Although conventional risk factors contribute to the onset and progression of PAD, the role of 'novel' biomarkers in pathways of inflammation, thrombosis, lipoprotein metabolism, and oxidative stress in determining susceptibility to PAD is being increasingly recognized. Validation of novel risk factors for PAD may allow earlier detection, an improved understanding of disease etiology and progression, and the development of new therapies. In this review, we discuss available evidence for associations between novel circulating markers and several aspects of PAD including disease susceptibility, progression, functional limitation, and adverse outcomes.

Hemostatic factors and subclinical brain infarction in a community-based sample: the ARIC study

BACKGROUND

Previous data are conflicting as to whether imbalance between hemostatic factors is associated with clinical strokes. We evaluated the association between hemostatic factor levels and subclinical lacunar infarcts in a nested sample from a subset of the Atherosclerosis Risk in Communities (ARIC) cohort.

METHODS

196 cases without clinical strokes had lacunar infarcts by MRI, and 214 controls without radiographic infarcts were frequency-matched by age group and sex. Logistic regression models were fitted to assess the association between levels of hemostatic markers and case status.

RESULTS

In age-, race- and sex-adjusted models, von Willebrand factor (vWF) and D-dimer were positively associated with case status, with odds ratios for the highest vs. lowest tertile of 2.0 (95% CI 1.2-3.6) for vWF and 1.76 (95% CI 1.02-3.0) for D-dimer. Plasminogen had nonsignificant inverse associations with presence of silent lacunar infarcts.

CONCLUSIONS

vWF and D-dimer were positively associated, and plasminogen was nonsignificantly inversely associated with subclinical radiographic infarct. Further studies on the role of these hemostatic factors in the development of silent lacunar infarcts may help elucidate the mechanisms behind this injury and may even point to potential targets for future intervention.

Haemostatic markers are associated with measures of vascular disease in adults with hypertension

Haemostatic markers have been implicated in the development and progression of vascular disease. We investigated the associations of several haemostatic markers (fibrinogen, D-dimer, FV, FVII, FVIII, von Willebrand factor (vWF) and antithrombin III) with two quantitative measures of vascular disease in adults with hypertension. Participants included 1051 African Americans (65+/-9 years, 72% women) and 894 non-Hispanic whites (61+/-9 years, 55% women) belonging to hypertensive sibships. Phenotypes of vascular disease included the ankle-brachial index (ABI), a measure of peripheral arterial disease, and urinary albumin/creatinine ratio (UACR), a surrogate of glomerular endothelial function. Generalized estimating equations were used to assess whether plasma levels of haemostatic markers were associated with measures of arteriosclerosis, after adjustment for conventional risk factors and medication (statin, aspirin and oestrogen) use. Higher fibrinogen and D-dimer were significantly associated with lower ABI in African Americans (P<0.001 and 0.004 respectively) and in non-Hispanic whites (P<0.001 and 0.010 respectively). Higher fibrinogen (P<0.001), D-dimer (P=0.003), FVIII (P<0.001) and vWF (P<0.001) were significantly associated with higher UACR in African Americans, whereas, in non-Hispanic whites, higher fibrinogen (P=0.020) and FVII (P=0.006) were significantly associated with higher UACR. Our findings indicate that in adults with essential hypertension, several markers in the haemostatic pathway are independently associated with ABI and UACR, two measures of vascular disease..

The association of active and passive smoking with peripheral arterial disease: results from NHANES 1999-2004

We aim to quantify the association between different forms of tobacco use and peripheral arterial disease (PAD) and to characterize the association between secondhand smoke exposure and PAD in a large nationally representative sample of the US population. We observed significant associations between current and former cigarette smoking and PAD. The association between noncigarette forms of tobacco and PAD was not significant even after adjustment for clinical and demographic variables. Secondhand smoke was not significantly associated with PAD. Interestingly, a ;;threshold phenomenon'' for tobacco exposure was demonstrated for PAD occurrence. Individuals with serum cotinine >155 ng/ mL were at significantly higher risk of having PAD as compared with a nonexistent or a minimal risk below this threshold value. Lack of association between PAD and secondhand smoke exposure in conjunction with the threshold phenomenon described above leads us to speculate existence of striking differences between the systemic circulation and lower extremity vasculature in terms of pathogenesis of atherosclerosis.

African-American ethnicity is associated with higher plasma levels of D-dimer in adults with hypertension

BACKGROUND

African Americans with hypertension have higher cardiovascular morbidity and mortality than hypertensives from other ethnic groups. Plasma D-dimer, a fragment generated from fibrin during lysis of mature clot in vivo, is a predictor of adverse cardiovascular events.

OBJECTIVE

We investigated whether plasma levels of D-dimer differ between African American (AA) and non-Hispanic white (NHW) adults with hypertension.

METHODS

Participants included 933 AA (65 +/- 9 years, 72% women) and 821 NHW (61 +/- 9 years, 56% women) from the community. D-dimer was measured using an immunoturbidimetric assay. Multivariable regression analyses, stratified by gender, were performed to assess whether AA ethnicity was associated with D-dimer levels after adjustment for age, body mass index (BMI), total and high-density lipoprotein (HDL) cholesterol, systolic blood pressure, diabetes, history of smoking, medication (statin and aspirin) use, lifestyle variables (physical activity, alcohol intake, and education), estimated glomerular filtration rate (eGFR), and a marker of inflammation, C-reactive protein (CRP).

RESULTS

D-dimer levels were higher in AA men and women than in their NHW counterparts (mean +/- SD; men 256 +/- 199 vs. 190 +/- 183 ng mL(-1), P < 0.001; women, 290 +/- 233 vs. 225 +/- 195 ng mL(-1), P < 0.001). In both sexes, after adjustment for age, conventional risk factors, medication use, and lifestyle variables, AA ethnicity remained associated with higher D-dimer levels (P = 0.002 in men, P = 0.006 in women). These associations remained significant after additional adjustment for eGFR and plasma CRP (P = 0.003 in men, P < 0.0001 in women).

CONCLUSIONS

Among adults with hypertension, AA ethnicity was independently associated with higher plasma levels of D-dimer.

Von Willebrand factor as marker of vascular function in South African women: the POWIRS Study

BACKGROUND

The increasing prevalence of hypertension and vascular-related morbidity and mortality among Africans emphasizes the need to identify markers for the early detection of vascular disease. Caucasian-based studies demonstrate that the von Willebrand factor (vWf) is a useful marker of vascular dysfunction. We investigated whether associations between this marker and markers of cardiovascular function in Caucasian women are comparable with African women.

METHODS

The study consisted of apparently healthy African (n = 99) and Caucasian (n = 114) women (mean age, 31.0 years), individually matched for age and body mass index. We measured blood pressure and arterial compliance noninvasively, and vWf in serum. We assessed univariate and multivariate-adjusted associations of blood pressure and arterial compliance with vWf.

RESULTS

Although no ethnic difference existed for mean vWf levels, Caucasian and African women showed opposite associations of blood pressure and arterial compliance with vWf after single, partial, and multiple regression analyses. In Caucasians, after full adjustment, systolic (beta = +0.179; P < 0.05) and diastolic (beta = +0.190; P < 0.05) blood pressure correlated positively and arterial compliance negatively (beta = -0.197; P < 0.01) with vWf. Conversely, in Africans, systolic blood pressure correlated weakly, but negatively (beta = -0.168; P = 0.059) with vWf. However, this opposite tendency seemed due to the confounding influence of the depot medroxyprogesterone acetate (DMPA) contraceptive injection and, although >99% power existed, significance disappeared after excluding these subjects (beta = -0.071; P = 0.46).

CONCLUSIONS

Associations of vWf with blood pressure and arterial compliance were not comparable between Caucasian and African women, suggesting that the vWf may not be a useful marker of vascular alterations in African women.