Association of the von Willebrand Factor-ADAMTS13 Ratio With Incident Cardiovascular Events in Patients With Peripheral Arterial Disease

A machine learning algorithm for peripheral artery disease prognosis using biomarker data

Peripheral artery disease (PAD) biomarkers have been studied in isolation; however, an algorithm that considers a protein panel to inform PAD prognosis may improve predictive accuracy. Biomarker-based prediction models were developed and evaluated using a model development (n = 270) and prospective validation cohort (n = 277). Plasma concentrations of 37 proteins were measured at baseline and the patients were followed for 2 years. The primary outcome was 2-year major adverse limb event (MALE; composite of vascular intervention or major amputation). Of the 37 proteins tested, 6 were differentially expressed in patients with vs. without PAD (ADAMTS13, ICAM-1, ANGPTL3, Alpha 1-microglobulin, GDF15, and endostatin). Using 10-fold cross-validation, we developed a random forest machine learning model that accurately predicts 2-year MALE in a prospective validation cohort of PAD patients using a 6-protein panel (AUROC 0.84). This algorithm can support PAD risk stratification, informing clinical decisions on further vascular evaluation and management.

Von Willebrand factor hyperactivity affects the outcome of lower limb revascularization in subjects with type 2 diabetes mellitus complicated by diabetic foot vasculopathy: An observational pilot study

Aim of this study is to evaluate any differences in VWF antigen, VWF activity and ADAMTS-13 activity before and after successful and non-successful Percutaneous Transluminal Angioplasty (PTA) in subjects with type 2 diabetes (T2DM) complicated by Chronic limb-threatening ischemia (CLTI) in diabetic foot vasculopathy.

METHODS

In this prospective observational pilot study, we enrolled 35 T2DM subjects who underwent lower limb PTA. Transcutaneous oximetry was performed in all patients before and 6 weeks after PTA. The change in oxygen partial pressure (TcpO2) before and after PTA was expressed as TcpO2-delta (ΔTcpO2). VWF antigen, VWF activity and ADAMTS-13 activity were measured before and 6 weeks after PTA; changes were expressed as delta and ratio from baseline.

RESULTS

Subjects with ∆TcpO2 < 15 mmHg presented higher ΔVWF activity (p = 0.050) and lower ADAMTS-13 activity ratio (p = 0.080). Subjects with ∆TcpO2 < 30 mmHg showed lower ADAMTS-13 activity Δ and ratio (p = 0.028).

CONCLUSIONS

VWF antigen levels and VWF activity may potentially affect PTA outcome. Higher levels of VWF could derive from VWF release as consequence of PTA-induced mechanical endothelial damage and/or oxidative stress-induced modifications of VWF structure with impairment of VWF-ADAMTS13 interactions.

Effects of catheter ablation of atrial fibrillation on the biomarker profile

BACKGROUND

Following catheter ablation for atrial fibrillation (AF), there are dynamic changes in the atrial myocardium associated with damage to and necrosis of atrial tissue and other procedure related changes in rhythm and anticoagulation. Early time-dependent changes in biomarkers of necrosis, inflammation, and coagulation have been reported. This study examines mid-term (4-8 weeks post-ablation) changes in biomarkers and explores their ability to predict AF recurrence at one-year.

METHODS

Twenty-seven patients (mean age 65.4 ± 9.7 years, 30% female) undergoing catheter ablation for AF had peripheral venous blood samples obtained at the time of ablation and 4-8 weeks later. All samples were processed to obtain plasma which was frozen for subsequent analysis. Coagulation studies were performed at the Northwestern Special Hemostasis Laboratory: VWF, ADAMTS13, PAI-1, D-dimer, and TAT complexes. A commercial lab analyzed samples for CRP, cystatin C, fibrinogen, galectin, IL-6, MMP-2, myoglobin, NT-proBNP, PAI-1, TIMP-1, TIMP-2, TPA, and VWF.

RESULTS

Significant changes were noted with higher levels of ADAMTS13 (p < 0.0001), fibrinogen (p = 0.004), MMP-2 (p = 0.0002), TIMP-2 (p = 0.003), and TPA (p = 0.001) compared to lower levels of TAT (p < 0.0001) and NT-proBNP (p = 0.0001) at follow up post-ablation. One year after ablation, AF had recurred in 11/26 (42%) of patients. None of the biomarker changes predicted the 1-year outcome, and there was no significant association with the use of warfarin versus rivaroxaban.

CONCLUSION

In patients undergoing catheter ablation for AF, there were significant changes in pre- vs post-ablation levels of multiple biomarkers. However, these changes were not associated with 1-year outcome of AF recurrence.

ADAMTS-13/von Willebrand factor ratio: A prognostic biomarker for portal vein thrombosis in compensated cirrhosis. A prospective observational study

BACKGROUND AND AIMS

In cirrhosis, decreased portal flow velocity, thrombophilia factors, and portal hypertension are considered risk factors for portal vein thrombosis (PVT). In cirrhosis, the transformation of the stellate cells causes a progressive decrease of ADAMTS-13, while VWF multimers secretion by endothelial cells is strongly enhanced. This imbalance leads to an accumulation of ultra-large VWF multimers that in sinusoidal circulation could favor PVT both in intra- and extra-hepatic branches, mostly in decompensated cirrhosis. This prospective study was aimed at identifying possible clinical, biochemical, and hemostatic factors predictive for non-tumoral PVT in a cohort of patients with compensated cirrhosis.

METHODS

Seventynine compensated cirrhosis patients were prospectively followed for 48 months, receiving a periodic Doppler-ultrasound liver examination associated with an extensive evaluation of clinical, biochemical, and hemostatic profile.

RESULTS

Five patients developed PVT (cumulative prevalence = 6.3%), occurring 4-36 months after enrollment. In logistic regression analysis, the ADAMTS-13/VWF:GpIbR ratio < 0.4 was the only independent variable significantly associated with PVT (OR 14.6, 95% C.I.:1.36-157.2, p = 0.027). A Cox-regression-analysis confirmed this finding (HR = 7.7, p = 0.027).

CONCLUSIONS

The ADAMTS-13/VWF ratio < 0.4 measured in compensated cirrhosis could be a reliable predictive biomarker for PVT development, paving the way to novel therapeutic strategies to prevent and treat PVT in this clinical setting.

The Role of the Coagulation System in Peripheral Arterial Disease: Interactions with the Arterial Wall and Its Vascular Microenvironment and Implications for Rational Therapies

Peripheral artery disease (PAD) is a clinical manifestation of atherosclerotic disease with a large-scale impact on the economy and global health. Despite the role played by platelets in the process of atherogenesis being well recognized, evidence has been increasing on the contribution of the coagulation system to the atherosclerosis formation and PAD development, with important repercussions for the therapeutic approach. Histopathological analysis and some clinical studies conducted on atherosclerotic plaques testify to the existence of different types of plaques. Likely, the role of coagulation in each specific type of plaque can be an important determinant in the histopathological composition of atherosclerosis and in its future stability. In this review, we analyze the molecular contribution of inflammation and the coagulation system on PAD pathogenesis, focusing on molecular similarities and differences between atherogenesis in PAD and coronary artery disease (CAD) and discussing the possible implications for current therapeutic strategies and future perspectives accounting for molecular inflammatory and coagulation targets. Understanding the role of cross-talking between coagulation and inflammation in atherosclerosis genesis and progression could help in choosing the right patients for future dual pathway inhibition strategies, where an antiplatelet agent is combined with an anticoagulant, whose role, despite pathophysiological premises and trials' results, is still under debate.

ADAM and ADAMTS disintegrin and metalloproteinases as major factors and molecular targets in vascular malfunction and disease

A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are two closely related families of proteolytic enzymes. ADAMs are largely membrane-bound enzymes that act as molecular scissors or sheddases of membrane-bound proteins, growth factors, cytokines, receptors and ligands, whereas ADAMTS are mainly secreted enzymes. ADAMs have a pro-domain, and a metalloproteinase, disintegrin, cysteine-rich and transmembrane domain. Similarly, ADAMTS family members have a pro-domain, and a metalloproteinase, disintegrin, and cysteine-rich domain, but instead of a transmembrane domain they have thrombospondin motifs. Most ADAMs and ADAMTS are activated by pro-protein convertases, and can be regulated by G-protein coupled receptor agonists, Ca²⁺ ionophores and protein kinase C. Activated ADAMs and ADAMTS participate in numerous vascular processes including angiogenesis, vascular smooth muscle cell proliferation and migration, vascular cell apoptosis, cell survival, tissue repair, and wound healing. ADAMs and ADAMTS also play a role in vascular malfunction and cardiovascular diseases such as hypertension, atherosclerosis, coronary artery disease, myocardial infarction, heart failure, peripheral artery disease, and vascular aneurysm. Decreased ADAMTS13 is involved in thrombotic thrombocytopenic purpura and microangiopathies. The activity of ADAMs and ADAMTS can be regulated by endogenous tissue inhibitors of metalloproteinases and other synthetic small molecule inhibitors. ADAMs and ADAMTS can be used as diagnostic biomarkers and molecular targets in cardiovascular disease, and modulators of ADAMs and ADAMTS activity may provide potential new approaches for the management of cardiovascular disorders.

Blood Plasma Serotonin and von Willebrand Factor as Biomarkers of Unstable Angina Progression Toward Myocardial Infarction

Aim: To investigate the serotonin and von Willebrand factor (vWF) concentrations among unstable angina (UA) patients without and with progression toward myocardial infarction (outcome) and to assess the utility of both as prognostic markers of UA complications. Materials and methods: In observational cohort study, we recruited 103 patients with ischemic heart disease (the median age 65.0 (59.0-69.0) years, 45 females (43.7%)). After full set of investigations including high sensitive Troponin I test and 28-day follow-up period, we defined three groups: Group 1 - stable angina patients (n=22) as control, Group 2 - UA patients without outcome (n=71), Group 3 - UA patients with outcome (n=10). We analyzed the blood plasma serotonin content by the ion-exchange chromatography with measurement of serotonin on fluorescence spectrophotometer. VWF concentration was determined by ELISA. We compared the concentrations of observed parameters among the groups with the Kruskal-Wallis test (with post-hoc Mann-Whitney test with Bonferroni-Holm correction). We assessed binary logistic models, receiver operating characteristic curves, calculated sensitivity (Se), specificity (Sp), and positive likelihood ratio (LR+) for each indicator. Results: We registered elevation in serotonin concentration and decline in vWF concentration in Group 3 in comparison with Group 2 (22.670 (20.687-24.927) μg/ml vs 11.980 (8.120-15.000) μg/ml, p< 0.001, and 0.117 (0.109-0.120) rel.units/ml vs 0.134 (0.127-0.143) rel.units/ml, p < 0.001) and Group 1 (12.340 (10.052-13.619) μg/ml, p < 0.001, and 0.137 (0.127-0.156) rel.units/ml, p < 0.001), respectively. No significant differences in serotonin and vWF concentrations between Group 1 and Group 2 were detected (p=0.81 and p=0.36, respectively). The probability of outcome increased significantly (by 60.7% and 59.7%, LR+ 19.0 [6.0, 60.0] and 18.0 [3.9, 80.0]) if serotonin concentration was above 21.575 μg/ml (Se=80.0%, Sp=95.8%, AUC=0.975) and vWF concentration was below 0.114 rel.units/ml (Se=50.0%, Sp=97.2%, AUC=0.973), respectively. Conclusions: Serotonin and vWF as biomarkers are demonstrated promising results for rule-in the patients with risk of short-term UA progression toward myocardial infarction.

Association of systemic inflammation and coagulation biomarkers with source-specific PM2.5 mass concentrations among young and elderly subjects in central Tehran

In this study, we investigated the association between short-term exposure to different sources of fine particulate matter (PM_2.5) and biomarkers of coagulation and inflammation in two different panels of elderly and healthy young individuals in central Tehran. Five biomarkers, including white blood cells (WBC), high sensitive C-reactive protein (hsCRP), tumor necrosis factor-soluble receptor-II (sTNF-RII), interleukin-6 (IL-6), and von Willebrand factor (vWF) were analyzed in the blood samples drawn every 8 weeks from the subjects between May 2012 and May 2013. The studied populations consisted of 44 elderly individuals at a retirement home as well as 40 young adults residing at a school dormitory. Positive Matrix Factorization (PMF)-resolved source-specific PM_2.5 mass concentrations and biomarker levels were used as the input to the linear mixed-effects regression model to evaluate the impact of exposure to previously identified PM sources at retirement home and school dormitory in two time lag configurations: lag 1-3 (1-3 days before the blood sampling), and lag 4-6 (4-6 days before the blood sampling). Our analysis of the elderly revealed positive associations of all biomarkers (except hsCRP) with particles of secondary origin in both time lags, further corroborating the toxicity of secondary aerosols formed by photochemical processing in central Tehran. Moreover, industrial emissions, and road dust particles were positively associated with WBC, sTNF-RII, and IL-6 among seniors, while vehicular emissions exhibited positive associations with all biomarkers in either first- or second-time lag. In contrast, most of the PM_2.5 sources showed insignificant associations with biomarkers of inflammation in the panel of healthy young subjects. Therefore, findings from this study indicated that various PM_2.5 sources increase the levels of inflammation and coagulation biomarkers, although the strength and significance of these associations vary depending on the type of PM sources, demographic characteristics, and differ across the different time lags. Implications: Tehran, the capital of Iran with a population of more than 9 million people, has been facing serious air pollution challenges as a result of extensive vehicular, and industrial activities in the previous years. Among various air pollutants in Tehran, fine particulate matters (PM_2.5, particles with aerodynamic diameters < 2.5 µm) are known as one of the most important critical pollutants, causing several adverse health impacts including lung cancer, respiratory, cardiovascular, and cardiopulmonary diseases. Therefore, a number of studies in the area have tried to investigate the adverse health impacts of exposure to PM_2.5. However, no studies have ever been conducted in Tehran to examine the association between specific PM_2.5 sources and biomarkers of coagulation and systemic inflammation as indicators of cardiovascular disorders. Indeed, this is the first study in the area investigating the association of source-specific PM_2.5 with biomarkers of inflammation including white blood cells (WBC), high sensitive C-reactive protein (hsCRP), tumor necrosis factor-soluble receptor-II (sTNF-RII), interleukin-6 (IL-6), and von Willebrand factor (vWF). Our results have important implications for policy makers in identifying the most toxic sources of PM_2.5, and in turn designing schemes for mitigating adverse health impacts of air pollution in Tehran.

Von Willebrand factor:antigen and ADAMTS-13 level, but not soluble P-selectin, are risk factors for the first asymptomatic deep vein thrombosis in cancer patients undergoing chemotherapy

Background

There is a high incidence of deep vein thrombosis (DVT) among cancer patients undergoing chemotherapy. Chemotherapy-induced vascular endothelial cell activation (VECA) is characterized by increased plasma levels of von Willebrand factor (vWF) and soluble P-selectin (sP-selectin), leading to the activation of endothelial cells and signaling cascades. The biological role of a disintegrin-like and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS-13) is to control the activity of vWF and consequently the risk of thrombosis. The objective of this study was to investigate the roles of sP-selectin, vWF, and ADAMTS-13 as risk factors for the first episode of DVT in cancer patients undergoing chemotherapy.

Methods

This prospective cohort study was conducted at Dr. Kariadi Hospital, Indonesia, on 40 cancer patients. Prechemotherapy (baseline) and postchemotherapy sP-selectin, vWF antigen (vWF:Ag), and ADAMTS-13 plasma levels were determined with ELISAs before and 3 months after chemotherapy. The clinical characteristics of the patients, cancer type, cancer stage, chemotherapy regimen, ABO blood type, D-dimer level and Khorana risk score were also analyzed using logistic regression. Patients were observed for the possibility of developing DVT during chemotherapy.

Results

DVT was confirmed in 5 patients (12.5%) after a period of 3 months. In patients with DVT, sP-selectin and vWF were significantly higher while ADAMTS-13 was lower than in their counterparts. The levels of baseline vWF:Ag and ADAMTS-13, with cut-off points ≥ 2.35 IU/mL and ≤ 1.03 IU/mL, respectively, were found to independently predict the incidence of DVT. In the multivariate logistic regression analysis, the relative risk (RR) for DVT in patients with high vWF:Ag was 3.80 (95% CI 1.15–12.48, p = 0.028), and that for patients with low ADAMTS-13 was 2.67 (95% CI 1.22–23.82, p = 0.005). The vWF:Ag/ADAMTS-13 ratio and both vWF:Ag and ADAMTS-13 dynamics during treatment were also able to differentiate those with prospective DVT. However, sP-selectin and other covariates showed no statistical significance.

Conclusion

We found that prechemotherapy plasma levels of vWF:Ag ≥ 2.35 IU/mL and ADAMTS-13 ≤ 1.03 IU/mL are independent risk factors for DVT incidence among cancer patients.

von Willebrand factor/ADAMTS13 ratio at presentation of acute ischemic brain injury is predictive of outcome

Acute ischemic stroke (IS) and transient ischemic attack (TIA) are associated with raised von Willebrand factor (VWF) and decreased ADAMTS13 activity (ADAMTS13Ac). Their impact on mortality and morbidity is unclear. We conducted a prospective investigation of the VWF-ADAMTS13 axis in 292 adults (acute IS, n = 103; TIA, n = 80; controls, n = 109) serially from presentation until >6 weeks. The National Institutes of Health Stroke Score (NIHSS) and modified Rankin scale (mRS) were used to assess stroke severity. Presenting median VWF antigen (VWF:Ag)/ADAMTS13Ac ratios were: IS, 2.42 (range, 0.78-9.53); TIA, 1.89 (range, 0.41-8.14); and controls, 1.69 (range, 0.25-15.63). Longitudinally, the median VWF:Ag/ADAMTS13Ac ratio decreased (IS, 2.42 to 1.66; P = .0008; TIA, 1.89 to 0.65; P < .0001). The VWF:Ag/ADAMTS13Ac ratio was higher at presentation in IS patients who died (3.683 vs 2.014; P < .0001). A presenting VWF:Ag/ADAMTS13Ac ratio >2.6 predicted mortality (odds ratio, 6.33; range, 2.22-18.1). Those with a VWF:Ag/ADAMTS13Ac ratio in the highest quartile (>3.091) had 31% increased risk mortality. VWF:Ag/ADAMTS13Ac ratio at presentation of ischemic brain injury was associated with higher mRS (P = .021) and NIHSS scores (P = .029) at follow-up. Thrombolysis resulted in prompt reduction of the VWF:Ag/ADAMTS13Ac ratio and significant improvement in mRS on follow-up. A raised VWF:Ag/ADAMTS13Ac ratio at presentation of acute IS or TIA is associated with increased mortality and poorer functional outcome. A ratio of 2.6 seems to differentiate outcome. Prompt reduction in the ratio in thrombolysed patients was associated with decreased mortality and morbidity. The VWF:Ag/ADAMTS13Ac ratio is a biomarker for the acute impact of an ischemic event and longer-term outcome.

Effect of Acute Myocardial Infarction on a Disintegrin and Metalloprotease with Thrombospondin Motif 13 and Von Willebrand Factor and Their Relationship with Markers of Inflammation

Objectives

Coagulation mechanisms and fibrinolytic assembly are important components role players of acute myocardial infarction (AMI) progression. Our study objective was to see the serial variations in the levels of Von Willebrand factor (VWF) and A Disintegrin and Metalloprotease with ThromboSpondin motif (ADAMTS13) over the course of AMI and to determine their relationship with the cardiovascular risk markers and the patient's clinical characteristics.

Methods

This project was done at the departments of Emergency Medicine, Physiology and Cardiac sciences of King Saud University Medical City. We studied ADAMTS13, VWF, fibrinogen, and CRP levels in 80 patients with AMI when patients were admitted; post AMI by 3-4 days and at follow-up of 3 months. We compared them with a control group consisting of 36 subjects.

Results

AMI had significantly lower levels of ADAMTS13 at AMI and after 3-4 days; at follow-up the difference in levels was nonsignificant, when compared with controls. Similarly, VWF levels were significantly higher in AMI and remained high even at follow-up compared to control subjects. VWF/ADAMTS13 ratio was also significantly higher at AMI and 3-4 days while at follow-up difference was nonsignificant compared to control subjects. Regression analysis between hsCRP and ADAMTS13 showed an inverse relationship (r = 0.376, p < 0.01), while correlation with VWF was significantly positive (r = 0.376, p < 0.01), while correlation with VWF was significantly positive (.

Conclusions

Increased levels of VWF and reduced levels of ADAMTS13 activity may contribute to the pathogenesis of acute myocardial infarction and might prove to be important mediators of AMI progression.

Biomarkers and Genetics in Peripheral Artery Disease

BACKGROUND

Peripheral artery disease (PAD) is highly prevalent and there is considerable diversity in the initial clinical manifestation and disease progression among individuals. Currently, there is no ideal biomarker to screen for PAD, to risk stratify patients with PAD, or to monitor therapeutic response to revascularization procedures. Advances in human genetics have markedly enhanced the ability to develop novel diagnostic and therapeutic approaches across a host of human diseases, but such developments in the field of PAD are lagging.

CONTENT

In this article, we will discuss the epidemiology, traditional risk factors for, and clinical presentations of PAD. We will discuss the possible role of genetic factors and gene-environment interactions in the development and/or progression of PAD. We will further explore future avenues through which genetic advances can be used to better our understanding of the pathophysiology of PAD and potentially find newer therapeutic targets. We will discuss the potential role of biomarkers in identifying patients at risk for PAD and for risk stratifying patients with PAD, and novel approaches to identification of reliable biomarkers in PAD.

SUMMARY

The exponential growth of genetic tools and newer technologies provides opportunities to investigate and identify newer pathways in the development and progression of PAD, and thereby in the identification of newer biomarkers and therapies.