Relationship Between Determinants of Arterial Stiffness Assessed by Diastolic and Suprasystolic Pulse Oscillometry: Comparison of Vicorder and Vascular Explorer

Relationship of proteins and subclinical cardiovascular traits in the population-based LIFE-Adult study

BACKGROUND AND AIMS

Understanding molecular processes of the early phase of atherosclerotic cardiovascular disease conditions is of utmost importance for early prediction and intervention measures.

METHODS

We measured 92 cardiovascular-disease-related proteins (Olink, Cardiovascular III) in 2024 elderly participants of the population-based LIFE-Adult study. We analysed the impact of 27 covariables on these proteins including blood counts, cardiovascular risk factors and life-style-related parameters. We also analysed protein associations with 13 subclinical cardiovascular traits comprising carotid intima media thickness, plaque burden, three modes of Vicorder-based pulse-wave velocities, ankle-brachial index and ECLIA-based N-terminal prohormone of brain natriuretic peptide (NT-proBNP).

RESULTS

Estimated glomerular filtration rate, triglycerides and sex where the most relevant covariables explaining more than 1 % variance of 49, 22 and 20 proteins, respectively. A total of 43 proteins were significantly associated with at least one of the analysed subclinical cardiovascular traits. NT-pro-BNP, brachial-ankle pulse-wave velocity (baPWV) and parameters of carotid plaque burden accounted for the largest number of associations. Association overlaps were relatively sparse. Only growth/differentiation factor 15, low density lipoprotein receptor and interleukin-1 receptor type 2 are associated with these three different cardiovascular traits. We confirmed several literature findings and found yet unreported associations for carotid plaque presence (von-Willebrand factor, galectin 4), carotid intima-media thickness (carboxypeptidase A1 andB1), baPWV (cathepsin D) and NT-proBNP (cathepsin Z, low density lipoprotein receptor, neurogenic locus homolog protein 3, trem-like transcript 2). Sex-interaction effects were observed, e.g. for spondin-1 and growth/differentiation factor 15 likely regulated by androgen response elements.

CONCLUSIONS

We extend the catalogue of proteome biomarkers possibly involved in early stages of cardiovascular disease pathologies providing targets for early risk prediction or intervention strategies.

Fully printed minimum port flexible interdigital electrode sensor arrays

Screen-printed interdigital electrode-based flexible pressure sensor arrays play a crucial role in human-computer interaction and health monitoring due to their simplicity of fabrication. However, the long-standing challenge of how to reduce the number of electrical output ports of interdigital electrodes to facilitate integration with back-end circuits is still commonly ignored. Here, we propose a screen-printing strategy to avoid wire cross-planes for rapid fabrication of flexible pressure sensor arrays. By innovatively introducing an insulating ink to realize electrical insulation and three-dimensional interconnection of wire crossings, the improved sensor array (4 × 4) successfully reduces the number of output ports from 17 to 8. In addition, we further constructed microstructures on the laser-etched electrode surfaces and the sensitive layer, which enabled the sensor to achieve a sensitivity as high as 17 567.5 kPa-1 in the range of 0-50 kPa. Moreover, we integrated the sensors with back-end circuits for the precise detection of tactile and physiological information. This provides a reliable method for preparing high-performance flexible sensor arrays and large-scale integration of microsensors.

Essential Hypertension and Oxidative Stress: Novel Future Perspectives

Among cardiovascular diseases, hypertension is one of the main risk factors predisposing to fatal complications. Oxidative stress and chronic inflammation have been identified as potentially responsible for the development of endothelial damage and vascular stiffness, two of the primum movens of hypertension and cardiovascular diseases. Based on these data, we conducted an open-label randomized study, first, to evaluate the endothelial damage and vascular stiffness in hypertense patients; second, to test the effect of supplementation with a physiological antioxidant (melatonin 1 mg/day for 1 year) in patients with essential hypertension vs. hypertensive controls. Twenty-three patients of either gender were enrolled and randomized 1:1 in two groups (control and supplemented group). The plasmatic total antioxidant capacity (as a marker of oxidative stress), blood pressure, arterial stiffness, and peripheral endothelial function were evaluated at the beginning of the study and after 1 year in both groups. Our results showed that arterial stiffness improved significantly (p = 0.022) in supplemented patients. The endothelial function increased too, even if not significantly (p = 0.688), after 1 year of melatonin administration. Moreover, the supplemented group showed a significative reduction in TAC levels (p = 0.041) correlated with the improvement of arterial stiffness. These data suggest that melatonin may play an important role in reducing the serum levels of TAC and, consequently, in improving arterial stiffness.

Functional versus morphological assessment of vascular age in patients with coronary heart disease

Communicating cardiovascular risk based on individual vascular age (VA) is a well acknowledged concept in patient education and disease prevention. VA may be derived functionally, e.g. by measurement of pulse wave velocity (PWV), or morphologically, e.g. by assessment of carotid intima-media thickness (cIMT). The purpose of this study was to investigate whether both approaches produce similar results. Within the context of the German subset of the EUROASPIRE IV survey, 501 patients with coronary heart disease underwent (a) oscillometric PWV measurement at the aortic, carotid-femoral and brachial-ankle site (PWVao, PWVcf, PWVba) and derivation of the aortic augmentation index (AIao); (b) bilateral cIMT assessment by high-resolution ultrasound at three sites (common, bulb, internal). Respective VA was calculated using published equations. According to VA derived from PWV, most patients exhibited values below chronological age indicating a counterintuitive healthier-than-anticipated vascular status: for VAPWVao in 68% of patients; for VAAIao in 52% of patients. By contrast, VA derived from cIMT delivered opposite results: e.g. according to VAtotal-cIMT accelerated vascular aging in 75% of patients. To strengthen the concept of VA, further efforts are needed to better standardise the current approaches to estimate VA and, thereby, to improve comparability and clinical utility.

Development of an Efficient, Non-Invasive Method for Cardiovascular Disease Risk Stratification in a Resource-Limited Setting

BACKGROUND

Augmentation Index (AIx) is considered as an important predictor of cardiovascular disease. So, quantification of AIx may provide a rapid cost-effective and non-invasive means of cardiovascular risk stratification. At present, WHO/ISH risk prediction charts are used to predict 10-year risk of a fatal or nonfatal major cardiovascular event, an assessment which requires laboratory support for blood chemistry and thus making it ill-suited for resource-limited settings.

OBJECTIVES

In this study, we examined the association of AIx with cardiovascular risk as determined by the WHO/ISH chart and identified AIx cut-offs to stratify patients into different risk categories.

METHODS

A case-control study with 162 cases and 61 controls was conducted in a tertiary care hospital in eastern India. Data were obtained for demographic, anthropometric, cardiovascular, and biochemical parameters. Cardiovascular risk assessment was carried out by WHO/ISH risk model in R. Statistical analysis was done for examining the association of AIx with WHO/ISH cardiovascular risk and for identifying AIx cut-offs to stratify patients into different risk categories.

RESULTS

Box and whisker plots for assessing the correlation between AIx and WHO/ISH cardiovascular risk showed an increase in the median value of AIx with increasing risk in both cases and controls. Heart rate corrected AIx showed a steady increase with increasing risk in males. AIx cutoffs showed good sensitivity and specificity for each risk category.

CONCLUSION

AIx is remarkably associated with cardiovascular risk as assessed by the WHO/ISH chart and the AIx cut-offs obtained in the study can be used as an efficient, non-invasive surrogate biomarker of cardiovascular risk even in resource-limited settings.

Genome-wide association analysis of pulse wave velocity traits provide new insights into the causal relationship between arterial stiffness and blood pressure

Background

The pathophysiology of arterial stiffness is not completely understood. Pulse wave velocity (PWV) is an established marker for arterial stiffness. We compare genetics of three PWV modes, namely carotid-femoral PWV (cfPWV), brachial-ankle (baPWV) and brachial-femoral (bfPWV), reflecting different vascular segments to analyse association with genetic variants, heritability and genetic correlation with other biological traits. Furthermore we searched for shared genetic architecture concerning PWV, blood pressure (BP) and coronary artery disease (CAD) and examined the causal relationship between PWV and BP.

Methods and results

We performed a genome-wide association study (GWAS) for cfPWV, baPWV and bfPWV in LIFE-Adult (N = 3,643–6,734). We analysed the overlap of detected genetic loci with those of BP and CAD and performed genetic correlation analyses. By bidirectional Mendelian Randomization, we assessed the causal relationships between PWV and BP. For cfPWV we identified a new locus with genome-wide significance near SLC4A7 on cytoband 3p24.1 (lead SNP rs939834: p = 2.05x10^-8). We replicated a known PWV locus on cytoband 14q32.2 near RP11-61O1.1 (lead SNPs: rs17773233, p = 1.38x10^-4; rs1381289, p = 1.91x10^-4) For baPWV we estimated a heritability of 28% and significant genetic correlation with hypertension (rg = 0.27, p = 6.65x10^-8). We showed a positive causal effect of systolic blood pressure on PWV modes (cfPWV: p = 1.51x10^-4; bfPWV: p = 1.45x10^-3; baPWV: p = 6.82x10^-15).

Conclusions

We identified a new locus for arterial stiffness and successfully replicated an earlier proposed locus. PWV shares common genetic architecture with BP and CAD. BP causally affects PWV. Larger studies are required to further unravel the genetic determinants and effects of PWV.

Radial Pulse Wave Signals Combined with Ba-PWV for the Risk Prediction of Hypertension and the Monitoring of Its Accompanying Metabolic Risk Factors

Our aim was to study whether radial pulse wave signals can improve the risk prediction of incident hypertension and are associated with its concomitant metabolic risk factors beyond the traditional cardiovascular risk factor Ba-PWV. By enrolling 523 Chinese subjects in this study, linear and stepwise regression analysis was performed to assess the association of radial artery pulse wave signals and Ba-PWV with blood pressure and its related metabolic risk factors such as fasting plasma glucose (FPG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and uric acid (UA). The area under the receiver-operating characteristic curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were calculated by risk assessment plot to compare the discriminative ability among models with and without radial artery pulse wave signals. After adjusting related confounding factors, radial artery pulse wave variable h 3/h 1 was selected as the sensitive influential factor for blood pressure. Moreover, a new model with h 3/h 1 had a higher AUC than the reference model without it (0.86 vs 0.84; P=0.030). And the NRI and IDI for the new model was 50.0% (P=0.017) and 3.16% (P=0.044), respectively. In addition to Ba-PWV, we found that the decrease of t 4, t 5, and h 5 might be associated with higher FPG, TC, LDL-C, and UA and lower HDL-C. This research might provide a valuable additional tool for remote wearable monitoring of radial artery pulse wave signals in hypertension risk evaluation and management.

Parameters of pulse wave velocity: determinants and reference values assessed in the population-based study LIFE-Adult

AIMS AND BACKGROUND

Parameters of arterial stiffness such as pulse wave velocity (PWV) were recently proposed as independent risk factors of cardiovascular events. We analyse three PWV parameters in the large population-based study LIFE-Adult to identify risk factors, normal and reference values.

METHODS AND RESULTS

Brachial-ankle (ba), brachial-femoral (bf) and carotid-femoral (cf) PWV assessment was performed using Vicorder device. 8509 participants aged 19-80 were analysed. PWV parameters were moderately correlated (r(ba/bf) = 0.6, r(ba/cf) = 0.46, r(bf/cf) = 0.59). Age and blood pressure are the dominant determinants of PWV parameters explaining > 18% of variability. Sex was only relevant for bfPWV and cfPWV. All further analysed cardiovascular and other risk factors are of minor importance. We provide age-dependent percentiles for the population (reference values) and for the subgroup of normotonic individuals. All percentiles show a strong increase with age. The difference between normotonic and all individuals is small for younger age groups but increases up to 1 m/s for elderly subjects.

CONCLUSION

Our study confirms and further underpins the strong impact of age and blood pressure on arterial stiffness and the relatively weak contribution of other factors, supporting an independent role of arterial stiffness in cardiovascular disease development. Age-dependent reference and normal values were provided on the basis of the so far largest study sample facilitating the implementation of PWV assessment in clinical practice. Due to better compliance, handling and stronger association with age and blood pressure, baPWV could serve as an alternative to cfPWV. Follow-up data are required to estimate the clinical significance of specified PWV cut-offs.

Maternal endothelial function and vascular stiffness after HELLP syndrome: a case-control study

OBJECTIVES

To assess endothelial function and arterial stiffness in women with a previous pregnancy complicated by pre-eclampsia (PE) with hemolysis, elevated liver enzymes and low platelet count (HELLP) syndrome, and to compare these findings to those in women with previous PE but no HELLP and to those in controls with previous uncomplicated pregnancy, in order to investigate the influence of HELLP syndrome on subsequent cardiovascular impairment.

METHODS

In this prospective single-center case-control study, we performed peripheral arterial tonometry (PAT) (using the EndoPAT method) and pulse-wave velocity (PWV) assessment in 109 women who had had a singleton pregnancy complicated by PE with (n = 49) or without (n = 60) HELLP syndrome, as well as in 60 controls with previous uncomplicated pregnancy, between 6 months and 4 years after delivery. The following EndoPAT and PWV indices were compared between groups: reactive hyperemia index (RHI), as an indication of endothelial function, and peripheral and aortic heart-rate-corrected augmentation indices (AIx) standardized for a heart rate of 75 bpm (AIx@75) and carotid-femoral pulse-wave velocity (cfPWV), as indications of arterial stiffness.

RESULTS

PAT and arterial stiffness indices were significantly different between PE cases, with or without previous HELLP, and controls, except for carotid-femoral PWV. There were no significant differences among PE groups: women who had experienced HELLP and those with a history of PE without HELLP showed similar rates of RHI ≤ 1.67 (28.6% vs 18.3%, P = 0.254) and RHI ≤ 2.00 (61.2% vs 41.7%, P = 0.055), peripheral AIx@75 ≥ 17% (38.8% vs 30.0%, P = 0.417), aortic AIx@75 ≥ 35% (29.2% vs 20.0%, P = 0.461) and cfPWV × 0.8 > 9.6 m/s, which occurred in only three women, all in the group without previous HELLP (0% vs 5.0%, P = 0.251). On multivariate regression analysis, HELLP syndrome, intrauterine growth restriction (IUGR) and early-onset PE independently predicted endothelial dysfunction at 6 months to 4 years postpartum, after correcting for uterine artery pulsatility index, birth-weight percentile, and maternal blood pressure, age and body mass index. Women with both previous HELLP and early-onset IUGR had a significantly higher prevalence of endothelial dysfunction (P = 0.001).

CONCLUSION

Similar vascular abnormalities were found in women previously affected by HELLP syndrome and those with previous PE without HELLP. However, a history of HELLP syndrome, IUGR and early-onset PE seems to identify a subgroup of women with a higher risk for future development of endothelial dysfunction. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.