Determinants of radial artery pulse wave analysis in asymptomatic individuals

Arterial Pulse Wave Velocity Signal Reconstruction Using Low Sampling Rates

Pulse Wave Velocity (PWV) analysis is valuable for assessing arterial stiffness and cardiovascular health and potentially for estimating blood pressure cufflessly. However, conventional PWV analysis from two transducers spaced closely poses challenges in data management, battery life, and developing the device for continuous real-time applications together along an artery, which typically need data to be recorded at high sampling rates. Specifically, although a pulse signal consists of low-frequency components when used for applications such as determining heart rate, the pulse transit time for transducers near each other along an artery takes place in the millisecond range, typically needing a high sampling rate. To overcome this issue, in this study, we present a novel approach that leverages the Nyquist-Shannon sampling theorem and reconstruction techniques for signals produced by bioimpedance transducers closely spaced along a radial artery. Specifically, we recorded bioimpedance artery pulse signals at a low sampling rate, reducing the data size and subsequently algorithmically reconstructing these signals at a higher sampling rate. We were able to retain vital transit time information and achieved enhanced precision that is comparable to the traditional high-rate sampling method. Our research demonstrates the viability of the algorithmic method for enabling PWV analysis from low-sampling-rate data, overcoming the constraints of conventional approaches. This technique has the potential to contribute to the development of cardiovascular health monitoring and diagnosis using closely spaced wearable devices for real-time and low-resource PWV assessment, enhancing patient care and cardiovascular disease management.

Impaired artery elasticity predicts cardiovascular morbidity and mortality- A longitudinal study in the Vara-Skövde Cohort

It is still debated whether arterial elasticity provides prognostic information for cardiovascular risk beyond blood pressure measurements in a healthy population. To investigate the association between arterial elasticity obtained by radial artery pulse wave analysis and risk for cardiovascular diseases (CVD) in men and women. In 2002-2005, 2362 individuals (men=1186, 50.2%) not taking antihypertensive medication were included. C2 (small artery elasticity) was measured using the HDI/Pulse Wave CR2000. Data on acute myocardial infarction or stroke, fatal or non-fatal, was obtained between 2002-2019. Cox- regression was used to investigate associations between C2 and future CVD, adjusting for confounding factors such as age, sex, systolic blood pressure, heart rate, HOMA-IR (Homeostatic Model Assessment for Insulin Resistance), LDL- cholesterol, CRP (C-Reactive Protein), alcohol consumption, smoking and physical activity. At baseline, the mean age of 46 ± 10.6 years and over the follow-up period, we observed 108 events 70 events in men [event rate: 5.9%], 38 in women [event rate: 3.2%]. In the fully adjusted model, and for each quartile decrease in C2, there was a significant increase in the risk for incident CVD by 36%. (HR = 1.36, 95% CI: 1.01-1.82, p = 0.041). The results were accentuated for all men (HR = 1.74, 95% CI: 1.21-2.50, p = 0.003) and women over the age of 50 years (HR = 1.70, 95% CI: 0.69-4.20). We showed a strong and independent association between C2 and CVD in men. In women after menopause, similar tendencies and effect sizes were observed.

Pulse Wave Analysis Method of Cardiovascular Parameters Extraction for Health Monitoring

OBJECTIVE

A pulse waveform is regarded as an information carrier of the cardiovascular system, which contains multiple interactive cardiovascular parameters reflecting physio-pathological states of bodies. Hence, multiple parameter analysis is increasingly meaningful to date but still cannot be easily achieved one by one due to the complex mapping between waveforms. This paper describes a new analysis method based on waveform recognition aimed for extracting multiple cardiovascular parameters to monitor public health. The objective of this new method is to deduce multiple cardiovascular parameters for a target pulse waveform based on waveform recognition to a most similar reference waveform in a given database or pattern library.

METHODS

The first part of the methodology includes building the sub-pattern libraries and training classifier. This provides a trained classifier and the sub-pattern library with reference pulse waveforms and known parameters. The second part is waveform analysis. The target waveform will be classified and output a state category being used to select the corresponding sub-pattern library with the same state. This will reduce subsequent recognition scope and computation costs. The mainstay of this new analysis method is improved dynamic time warping (DTW). This improved DTW and K-Nearest Neighbors (KNN) were applied to recognize the most similar waveform in the pattern library. Hence, cardiovascular parameters can be assigned accordingly from the most similar waveform in the pattern library.

RESULTS

Four hundred and thirty eight (438) randomly selected pulse waveforms were tested to verify the effectiveness of this method. The results show that the classification accuracy is 96.35%. Using statistical analysis to compare the target sample waveforms and the recognized reference ones from within the pattern library, most correlation coefficients are beyond 0.99. Each set of cardiovascular parameters was assessed using the Bland-Altman plot. The extracted cardiovascular parameters are in strong agreement with the original verifying the effectiveness of this new approach.

CONCLUSION

This new method using waveform recognition shows promising results that can directly extract multiple cardiovascular parameters from waveforms with high accuracy. This new approach is efficient and effective and is very promising for future continuous monitoring of cardiovascular health.

The pulse waveform quantification method basing on contour and derivative

OBJECTIVE

Pulse waveform contains abundant physiological and pathological information. The condition of surrounding arteries can be reflected sensitively by the contour and derivative changes of pulse waves. In order to express these changes objectively, the pulse wave needs to be quantified.

METHODS

This study provides a novel quantification method for pulse waveform in the entire cardiac cycle. It involves two new quantification parameters k1 and k2 to display the waveform change caused by the superimposition of wave reflection in the systolic reflex period, which is the most significant changes period. In this method, multi parameters were fused by Kalman filter to obtain an optimal estimation, involving the new parameters and other parameters: k0 for the early systolic period, C1 and C2 for diastole period, and K for pulse pressure.

RESULTS

Use correlation analysis to verify the effectiveness of new parameters that the coefficient is 0.7 between them and the typical augmentation index (AIx). The quantification results of 462 single-cycle pulse waves have consistent change trends with aging in 25-75 different age groups. For respiration analysis, the correlation coefficients are all greater than 0.6, even achieved 0.8 in six multi-cycle data between Kalman optimal estimation and breath wave.

CONCLUSION

This method has quantified the waveform change with physiological status, and these quantification parameters can display the detail of each period.

SIGNIFICANCE

It will be used to verify waveform recognition accuracy and has a vast potential to detect diseases.

In situ controlled and conformal coating of polydimethylsiloxane foams with silver nanoparticle networks with tunable piezo-resistive properties

Nanoparticle-polymer composites hold promise in enabling material functionalities that are difficult to achieve otherwise, yet are hampered to date by the scarce control and tunability of the nanoparticle collective properties on the polymer surface, especially for polymer foams featuring a complex three-dimensional pore network. Here we report on the controlled and conformal in situ coating of polydimethylsiloxane (PDMS) foams with silver nanoparticles (AgNPs) with surface coverage finely tunable over a large range, from 0 to 75%, via the one-step room temperature reduction of AgF directly on the PDMS surface. This enables the design of AgNP electrical networks on the PDMS foam surface with piezo-resistive properties tunable up to a factor of 1000. We leveraged the control of the piezoresistive properties of the AgNP electrical network formed on PDMS foams to fabricate flexible and wearable pressure sensors with sensitivity of 0.41 kPa^-1, an operation range >120 kPa, and a detection limit of 25 Pa. As a proof-of-concept application in wearable biomedical electronics, we successfully used the sensors to monitor the real-time radial artery pulse wave on the human wrist of a young male with high resolution.

Higher carotid-radial pulse wave velocity is associated with non-melancholic depressive symptoms in men - findings from Helsinki Birth Cohort Study

BACKGROUND

Depression and cardiovascular disease (CVD) are major causes of global disease burden that are interrelated through mostly unknown mechanisms. We studied the relationship of melancholic and non-melancholic depressive symptoms with arterial stiffness, an important underlying mechanism of CVD.

METHODS

The Helsinki Birth Cohort Study recruited 683 previously extensively phenotyped subjects for this sub-study. Cross-sectional data along with responses regarding depressive symptoms were obtained for each participant. For evaluation of depressive symptoms, the Beck Depression Inventory (BDI)and subscales were used to measure melancholic and non-melancholic depressive symptoms. Arterial stiffness was assessed as pulse wave velocity (PWV) that was measured between the carotid and radial artery, and carotid and femoral artery.

RESULTS

Of the participants, 532 scored <10 on the BDI and were classified as not having depressive symptoms. Of the 151 participants that scored ≥10 on the BDI, 122 were classified as having non-melancholic depressive symptoms and 29 as having melancholic depressive symptoms. Men had higher carotid-radial PWV (crPWV) values than women (p < .001). A positive relationship between BDI scores and crPWV (p < .001) was found in men. We also found higher crPWV in men with non-melancholic depressive symptoms compared to all others. No such differences were found in women.

DISCUSSION

Arterial stiffness has a relationship with depressive symptoms and subtypes of depressive symptoms, at least in men. There is a significant relationship between higher PWV and non-melancholic depressive symptoms in men. Due to the intricate nature of the disease causality or directionality is impossible to infer solely based on this study. Further studies into the subtypes of depressive symptoms may be of benefit to understanding depression.KEY MESSAGESIt is known that arterial stiffness contributes to cardiovascular disease, and is associated with depression.Higher Beck Depression Inventory scores are associated with higher carotid-radial pulse wave velocity in men.Non-melancholic depressive symptoms are associated with higher carotid-radial pulse wave velocity in men.

Harnessing the Wide-range Strain Sensitivity of Bilayered PEDOT:PSS Films for Wearable Health Monitoring

Mechanical deformation of human skin provides essential information about human motions, muscle stretching, vocal fold vibration, and heart rates. Monitoring these activities requires the measurement of strains at different levels. Herein, we report a wearable wide-range strain sensor based on conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). A bioinspired bilayer structure was constructed to enable a wide-range strain sensing (1%~100%). Besides, hydrogel was chosen as the biological- and mechanical-compatible interface layer with the human skin. Finally, we demonstrated that the strain sensor is capable of monitoring various strain-related activities, including subtle skin deformation (pulse and phonation), mid-level body stretch (swallowing and facial expressions), and substantial joint movement (elbow bending).

Longitudinal association between leisure-time physical activity and vascular elasticity indices

AIM

We investigated the association between levels of leisure-time physical activity and vascular stiffness in a longitudinal observational study from a representative Swedish population.

METHOD

A total of 2816 randomly selected individuals were examined at visit 1 (2002-2005, Men = 1400). After a mean follow-up of 9.7 ± 1.4 years, a representative sample of 1327 of the original participants were re-examined at visit 2. After excluding subjects with hypertension at baseline, 761 participants were included in the longitudinal analyses. Leisure-time physical (LTPA) activity was self-reported and dichotomized as high or low (level 3, 4 and level 1, 2, respectively). Large Arterial Elasticity Index (LAEI) and Small Arterial Elasticity Index (SAEI) were measured using the HDI/Pulse Wave™ CR2000. Multivariable general linear models were used to investigate the differences in changes SAEI and LAEI based on LTPA levels.

RESULTS

At visit 1, and after adjustment for possible confounders, participants in the high LTPA group had better small artery elasticity (SAEI) (SAEI in low-level LTPA: 7.89 ± 0.11, SAEI in high-level LTPA: 8.32 ± 0.15, ΔSAEI: 0.42, CI: 0.07-0.78; p = 0.020). SAEI decreased between the two assessments (Visit 1: SAEI 8.01 ± 3.37 ml/mmHg; Δ SAEI: 1.4, CI 1.2-1.6, p < 0.001). Participants with a higher LTPA at visit 1 had significantly better SAEI at visit 2 (ΔSAEI: 0.44, CI 0.03-0.85, p = 0.037). No significant associations were observed between LAEI and LTPA after adjustments.

CONCLUSIONS

High LTPA predicted higher small arterial compliance at visit 2 suggesting that positive effects of LTPA on arterial elasticity persists over time.

A Wearable Sensor Using Structured Silver-Particle Reinforced PDMS for Radial Arterial Pulse Wave Monitoring

Human pulse signals contain important and useful physiological information for the auxiliary diagnosis of cardiovascular disease. Here, a wearable pulse sensor based on piezo-thermic transduction is reported using a structured silver-particle reinforced polydimethylsiloxane (PDMS) membrane, for monitoring radial arterial pulse waves. The structured silver-particle reinforced PDMS membrane is optimally designed to meet the specific requirements on sensitivity, linearity, and effective preload measuring range for pulse detection by adjusting the air gap volume fraction and silver particle volume fraction of the structured material. The sensor is endowed with high sensitivity, good linearity in preload measuring range, allowing to detect the subtle pulse waveforms of subjects at different ages under different contact pressures, such as superficial (Fu), medium (Zhong) and deep (Chen). The developed pulse device provides a promising approach for homecare pulse monitoring.

Multilevel Microstructured Flexible Pressure Sensors with Ultrahigh Sensitivity and Ultrawide Pressure Range for Versatile Electronic Skins

Flexible pressure sensors as electronic skins have attracted wide attention to their potential applications for healthcare and intelligent robotics. However, the tradeoff between their sensitivity and pressure range restricts their practical applications in various healthcare fields. Herein, a cost-effective flexible pressure sensor with an ultrahigh sensitivity over an ultrawide pressure-range is developed by combining a sandpaper-molded multilevel microstructured polydimethylsiloxane and a reduced oxide graphene film. The unique multilevel microstructure via a two-step sandpaper-molding method leads to an ultrahigh sensitivity (2.5-1051 kPa^-1 ) and can detect subtle and large pressure over an ultrawide range (0.01-400 kPa), which covers the overall pressure regime in daily life. Sharp increases in the contact area and additional contact sites caused by the multilevel microstructures jointly contribute to such unprecedented performance, which is confirmed by in situ observation of the gap variations and the contact states of the sensor under different pressures. Examples of the flexible pressure sensors are shown in potential applications involving the detection of various human physiological signals, such as breathing rate, vocal-cord vibration, heart rate, wrist pulse, and foot plantar pressure. Another object manipulation application is also demonstrated, where the material shows its great potential as electronic skin intelligent robotics and prosthetic limbs.

Living Arrangement: a Contributor to Vascular Disease in Asymptomatic African American Women

BACKGROUND

Diminished social support lias shown to lead to worse cardiovascular outcomes and since cardiovascular disease (CVD) is the leading cause of death in the United States (U.S.), it is critical to non-invasively study its precursor- vascular disease (VD). Assessing the impact social support lias on vascular outcomes can unveil potential CVD susceptibilities in at-risk populations. African American women exhibit the greatest burden of CVD morbidity and mortality; therefore, the purpose of tins study is to examine the association between living arrangement/social support and impaired vascular function in asymptomatic African American women.

METHODS

Vascular function was assessed by a non-invasive screening tool, HDI/PulseWave CR-2000, during screenings at community outreach events on participants clinically free of CVD. Vascular disease was defined as abnormal/impaired vascular function. Living arrangement, a binary variable (living with someone/living alone), was determined by survey responses (N=67) and represented social support. Multivariable analyses were used to estimate adjusted odds ratios (AORs) and 95% confidence intervals (95% CIs) to determine the association between living arrangement and vascular disease after controlling for confounders. Analyses were conducted using SAS 9.2.

RESULTS

Of those who lived alone, 82% had vascular disease (p=0.03). After adjusting for family CVD, and other CVD risk factors, those who lived with a spouse/partner or relative were 78% (p=0.04) less likely to develop vascular disease (AOR=0.22; 95% 0=0.05, 0.98).

CONCLUSIONS

Our study provides preliminary evidence to suggest that among African American women, clinically free of CVD, living arrangement is associated with vascular disease. While living alone may place individuals at an increased risk of CVD because of the association, living with a spouse/partner or relative may act as a protective factor against vascular disease and reduce the risk of CVD. Public health practitioners may use individuals' living arrangement as preventive measure for CVD risk.

Pulse wave response characteristics for thickness and hardness of the cover layer in pulse sensors to measure radial artery pulse

Background

Piezo-resistive pressure sensors are widely used for measuring pulse waves of the radial artery. Pulse sensors are generally fabricated with a cover layer because pressure sensors without a cover layer are fragile when they come into direct contact with the skin near the radial artery. However, no study has evaluated the dynamic pulse wave response of pulse sensors depending on the thickness and hardness of the cover layer. This study analyzed the dynamic pulse wave response according to the thickness and hardness of the cover layer and suggests an appropriate thickness and hardness for the design of pulse sensors with semiconductor device-based pressure sensors.

Methods

Pulse sensors with 6 different cover layers with various thicknesses (0.8 mm, 1 mm, 2 mm) and hardnesses (Shore type A; 30, 43, 49, 71) were fabricated. Experiments for evaluating the dynamic pulse responses of the fabricated sensors were performed using a pulse simulator to transmit the same pulse wave to each of the sensors. To evaluate the dynamic responses of the fabricated pulse sensors, experiments with the pulse sensors were conducted using a simulator that artificially generated a constant pulse wave. The pulse wave simulator consisted of a motorized cam device that generated the artificial radial pulse waveform by adjusting the stroke of the cylindrical air pump and an air tube that conveyed the pulse to the artificial wrist.

Results

The amplitude of the measured pulse pressure decreased with increasing thickness and hardness of the cover layer. Normalized waveform analysis showed that the thickness rather than the hardness of the cover layer contributed more to waveform distortion. Analysis of the channel distribution of the pulse sensor with respect to the applied constant dynamic pressure showed that the material of the cover layer had a large effect.

Conclusions

In this study, in-line array pulse sensors with various cover layers were fabricated, the dynamic pulse wave responses according to the thickness and the hardness of the cover layer were analyzed, and an appropriate thickness and hardness for the cover layer were suggested. The dynamic pulse wave responses of pulse sensors revealed in this study will contribute to the fabrication of improved pulse sensors and pulse wave analyses.

Evaluation of arterial stiffness and cardiac function in patients with vascular erectile dysfunction: acute effects of phosphodiesterase-5 inhibitor tadalafil

This study aimed to detect endothelial dysfunction in erectile dysfunction (ED) patients free from cardiovascular diseases or atherosclerotic risk factors and to evaluate acute effects of phosphodiesterase-5 inhibitor tadalafil on endothelial dysfunction and cardiac function. Thirty ED patients and 20 healthy male subjects (mean ages: 48.7±11.7 and 48.3±8.7 years, respectively) were enrolled. Endothelium functions were assessed by applanation tonometry. Aortic stiffness and cardiac function were evaluated by transthoracic echocardiography. Pulse pressure was greater in the ED group (P<0.05), whereas aortic strain and aortic distensibility were significantly lower (P<0.001). Treatment with tadalafil reduced pulse pressure (P=0.0179), systolic blood pressure (P=0.001) and diastolic blood pressure (P=0.054) and increased aortic distensibility (P=0.001) and aortic strain (P=0.003) in the ED group. Tadalafil administration also increased large artery and small artery elasticity indices that were reduced in the ED group at baseline (P=0.02 and 0.003, respectively). Systemic vascular disease and compromised left ventricular diastolic function (LVDF) were present in ED patients with no known atherosclerotic risk factors and cardiac diseases. Tadalafil positively affected arterial stiffness and LVDF.

Aortic augmentation index in endurance athletes: a role for cardiorespiratory fitness

PURPOSE

Endurance exercise improves cardiovascular health and reduces mortality risk. Augmentation index (AIx) reflects adverse loading exerted on the heart and large arteries and predicts future cardiovascular disease. The purpose of this study was to establish whether endurance athletes possess lower AIx and aortic blood pressure compared to healthy controls, and to determine the association between AIx and cardiorespiratory fitness.

METHODS

Forty-six endurance athletes and 43 healthy controls underwent central BP and AIx measurements by non-invasive applanation tonometry before a maximal exercise test. Peak oxygen uptake ([Formula: see text]) was assessed by pulmonary analysis.

RESULTS

Relative to controls, athletes had significantly lower brachial diastolic blood pressure (BP, -4.8 mmHg, p < 0.01), central systolic BP (-3.5 mmHg, p = 0.07), and AIx at a heart rate of 75 beats min(-1) (AIx@75, -11.9 %, p < 0.001). No AIx@75 differences were observed between athletes and controls when adjusted for age and [Formula: see text] [athletes vs controls mean (%) ± SE: -6.9 ± 2.2 vs -5.7 ± 2.3, p = 0.76]. Relative to men with low [Formula: see text], those with moderate and high [Formula: see text] had lower age-adjusted AIx@75 (p < 0.001). In women, those with high [Formula: see text] had lower AIx@75 than those with low and moderate [Formula: see text] (p < 0.01).

CONCLUSIONS

The lower AIx@75 in endurance athletes is partly mediated by [Formula: see text]. While an inverse relationship between AIx@75 and [Formula: see text] was found in men, women with the highest [Formula: see text] possessed lowest AIx@75 compared to females with moderate or poor cardiorespiratory fitness. We recommend aerobic training aimed at achieving a minimum [Formula: see text] of 45 ml kg(-1) min(-1) to decrease the risk of future cardiovascular events and all-cause mortality.

The influence of obesity on arterial compliance in adult men and women

The objective of this study was to determine whether differences in large and small arterial compliance existed among normal weight, overweight, and obese older men and women, and whether large and small arterial compliance were associated with abdominal, hip, and subcutaneous fat distribution. A total of 134 individuals who were 40 years of age and older (age = 62 ± 11 years; mean ± SD) were grouped into normal weight (BMI: 18.5—24.9 kg/m2; n = 33), overweight (BMI: 25.0—29.9 kg/m2; n = 48), or obese (BMI: ≥30.0 kg/m2; n = 53) categories. The hemodynamic and arterial compliance measurements were obtained using the HDI/PulseWave CR-2000 CardioVascular Profiling System (Hypertension Diagnostics, Inc). Body mass index, nine-site sum of skinfolds, and circumference measures around the hip and waist were used for analysis. Large and small arterial compliance was lower (p < 0.001) in the obese group (12.4 ± 4.8 ml/mmHg × 10 vs 4.6 ± 2.5 ml/mmHg × 100, respectively) than the normal weight (16.2 ± 4.9 ml/mmHg × 10 vs 5.5 ± 2.7 ml/mmHg × 100) and overweight (15.2 ± 4.3 ml/mmHg × 10 vs 5.0 ± 2.2 ml/mmHg × 100) groups. This difference remained (p < 0.001) after adjusting for body surface area, sex, hyperlipidemia, and hypertension. Additionally, large arterial compliance correlated (p < 0.05) with sum of skinfolds (r = — 0.209), while small arterial compliance correlated with hip circumference (r = — 0.189). Arterial compliance measures were not related (p > 0.05) to waist circumference or waist-to-hip ratio. In conclusion, obesity was associated with a decrease in large and small arterial compliance independent of conventional risk factors. Additionally, subcutaneous fat and fat around the hips were inversely related to arterial compliance.

Autonomic Nervous System Responses to Concussion: Arterial Pulse Contour Analysis

The arterial pulse wave (APW) has a distinct morphology whose contours reflect dynamics in cardiac function and peripheral vascular tone as a result of sympathetic nervous system (SNS) control. With a transition from rest to increased metabolic demand, the expected augmentation of SNS outflow will not only affect arterial blood pressure and heart rate but it will also induce changes to the contours of the APW. Following a sports concussion, a transient state cardiovascular autonomic dysfunction is present. How this state affects the APW has yet to be described. A prospective, parallel-group study on cardiovascular autonomic control (i.e., digital electrocardiogram and continuous beat-to-beat blood pressure) was performed in the seated upright position in 10 athletes with concussion and 7 non-injured control athletes. Changes in APW were compared at rest and during the first 60 s (F60) of an isometric handgrip test (IHGT) in concussed athletes and non-injured controls within 48 h and 1 week of injury. The concussion group was further separated by the length of time until they were permitted to return to play (RTP > 1week; RTP ≤ 1week). SysSlope, an indirect measurement of stroke volume, was significantly lower in the concussion group at rest and during F60 at 48 h and 1week; a paradoxical decline in SysSlope occurred at each visit during the transition from rest to IHGT F60. The RTP > 1week group had lower SysSlope (405 ± 200; 420 ± 88; 454 ± 236 mmHg/s, respectively) at rest 48 h compared to the RTP ≤ 1week and controls. Similarly at 48 h rest, several measurements of arterial stiffness were abnormal in RTP > 1week compared to RTP ≤ 1week and controls: peak-to-notch latency (0.12 ± 0.04; 0.16 ± 0.02; 0.17 ± 0.05, respectively), notch relative amplitude (0.70 ± 0.03; 0.71 ± 0.04; 0.66 ± 0.14, respectively), and stiffness index (6.4 ± 0.2; 5.7 ± 0.4; 5.8 ± 0.5, respectively). Use of APW revealed that concussed athletes have a transient increase in peripheral artery stiffness, which may be a compensatory adaptation to a paradoxical decline of stroke volume during the transition from rest to a state of increased metabolic demand within 48 h of concussion. This dysfunction of the SNS appeared to be more pronounced among concussed athletes who were removed from participation for >1 week compared to those who resumed play within 7 days.

Solution-Processed Large-Area Nanocrystal Arrays of Metal-Organic Frameworks as Wearable, Ultrasensitive, Electronic Skin for Health Monitoring

Pressure sensors based on solution-processed metal-organic frameworks nanowire arrays are fabricated with very low cost, flexibility, high sensitivity, and ease of integration into sensor arrays. Furthermore, the pressure sensors are suitable for monitoring and diagnosing biomedical signals such as radial artery pressure waveforms in real time.

Radial augmentation index is a surrogate marker of atherosclerotic burden in a primary prevention cohort

Arterial stiffness is linked to cardiovascular risk and predicts clinical events independently of peripheral blood pressure. The potential relationship between the augmentation index measured at the radial artery and asymptomatic atherosclerosis remains unclear however. In order to assess relationship between the peripheral augmentation index and traditional risk factors, we estimated cardiovascular risk and presence of subclinical atherosclerosis in a large asymptomatic population in primary prevention. Patients in primary prevention (n = 1007) with at least 1 cardiovascular risk factor were included and radial augmentation index was measured. Maximum common carotid intima-media thickness, the presence of plaque and Framingham 10 year cardiovascular risk score were assessed. The mean augmentation index was 81 ± 13% in a population composed of 55% males (mean age 56 years). The augmentation index differed significantly between men (77 ± 12%) and women (86 ± 12%). In the global population, augmentation index was negatively correlated to height and weight, and positively correlated to cardiovascular risk, age, systolic blood pressure, pulse pressure, diabetes, HDL-Cholesterol, fasting glucose, intima-media thickness and to the presence of plaques. Multivariate analysis in the global and in the male population revealed an independent and positive relationship between augmentation index and intima-media thickness on the one hand, and between augmentation index and the presence of plaque on the other. Our results confirm that there are significant relationships between a surrogate marker of arterial stiffness and subclinical atherosclerosis in a large primary prevention population.

Metabolic syndrome and arterial elasticity in youth

OBJECTIVE

To compare arterial elasticity in children, adolescents, and young adults with and without metabolic syndrome (MetS), and to assess which MetS components, demographic measures, and body composition measures are associated with arterial elasticity.

MATERIALS/METHODS

Two-hundred six subjects (107 females and 99 males) between the ages of 10 and 20years were recruited by local newspaper advertisements, university email advertisements, and informational flyers. Subjects were assessed on MetS components, demographic measures, body composition measures, and arterial elasticity via radial tonometry. Forty-five subjects (22%) had MetS, as defined by the International Diabetes Federation, and 161 subjects (78%) did not.

RESULTS

The primary novel finding was that group differences were not observed for large artery elasticity index (LAEI) (MetS=16.1±4.4 (ml×mmHg(-1))×10 (mean±SD), control=15.4±4.9, (ml×mmHg(-1))×10, p=0.349), and small artery elasticity index (SAEI) (MetS=9.2±2.7 (ml×mmHg(-1))×100, control=8.4±2.9, (ml×mmHg(-1))×100, p=0.063). In the MetS group, fat free mass was positively associated with arterial elasticity, and was the strongest multivariate predictor of LAEI (partial R(2)=0.41) and SAEI (partial R(2)=0.29).

CONCLUSIONS

Youth with MetS did not exhibit differences in LAEI and SAEI compared to controls. Furthermore, fat free mass of youth with MetS was positively associated with arterial elasticity, and was the strongest predictor of both LAEI and SAEI. The clinical implication is that exercise intervention designed to increase fat free mass might increase arterial elasticity in youth, particularly in youth with MetS.

The association of 25(OH)D with blood pressure, pulse pressure and carotid-radial pulse wave velocity in African women

High susceptibility of the African population to develop cardiovascular disease obliges us to investigate possible contributing risk factors. Our aim was to determine whether low 25(OH)D status is associated with increased blood pressure and carotid-radial pulse wave velocity in black South African women. We studied 291 urban women (mean age: 57.56±9.00 yrs.). 25(OH)D status was determined by serum 25(OH)D levels. Women were stratified into sufficient (>30 ng/ml), and insufficient/deficient (<30 ng/ml) groups. Cardiovascular variables were compared between groups. Women with low 25(OH)D levels had significantly higher SBP (150.8±27.1 vs. 137.6±21.0), DBP (94.7±14.5 vs. 89.3±12.3) and PP (53.15(50.7;55.7) vs. 46.3(29.4;84.6)) compared to women with sufficient levels. No significant difference was observed with regards to c-rPWV. ANCOVA analyses still revealed significant differences between the two groups with regards to SBP, DBP as well as PP. Partial correlations revealed significant inverse association between SBP and 25(OH)D (p = .04;r = −.12). Women with low 25(OH)D levels were ∼2 times more likely to have high SBP (95% CI: 3.23;1.05). To conclude, women with deficient/insufficient 25(OH)D had significantly higher SBP compared to women with a sufficient 25(OH) status.

Association between Endothelial Biomarkers and Arterial Elasticity in Young Adults - The CARDIA Study

BACKGROUND

Reduced arterial elasticity and endothelial dysfunction both may indicate early cardiovascular (CV) disease in young adults. Pulse waveform analysis estimates large (LAE) and small (SAE) artery elasticity noninvasively. We assessed the associations between LAE and SAE and markers of endothelial dysfunction and CV risk factors.

METHODS

The Coronary Artery Risk Development in Young Adults (CARDIA) assessed arterial elasticity and other characteristics cross-sectionally in 389 men and 381 women aged 27-42 years in 1995 (CARDIA year 10) and circulating levels of P-selectin and soluble intercellular adhesion molecule 1 (sICAM-1) in 2000. We adjusted for variables included in the estimation of arterial elasticity (year 10 height, body mass index, age, heart rate, and blood pressure) and other year 10 characteristics.

RESULTS

Mean adjusted SAE was 8.5 vs. 7.6 ml/mmHg x100 in those with urine albumin/creatinine ratio </=4 vs. microalbuminuria (ratio > 25; p(trend) =0.008). Mean LAE was 25.6 vs. 24.2 ml/mmHg x10 in the lowest vs. highest quintile of P-selectin (p(trend) =0.004). sICAM-1 was unrelated to either LAE or SAE. Plasma triglycerides were inversely related to LAE (p(trend) =0.029). Cigarette smokers had lower SAE than nonsmokers (p(trend) = 0.009).

CONCLUSION

In addition to smoking and triglycerides, biomarkers for endothelial dysfunction were associated with impaired LAE and SAE in young adults.

Arterial elasticity and oxidized LDL among men with metabolic syndrome and different 10-year cardiovascular risk estimated by FINRISK and SCORE models

BACKGROUND

SCORE and FINRISK models are designed to estimate patient's risk for cardiovascular diseases (CVD). Increased circulating oxidized LDL (oxLDL) and impaired arterial elasticity, on their part, are considered as markers of subclinical atherosclerosis. Subjects with metabolic syndrome (MetS) are thought to be at high risk for CVD because of metabolic abnormalities.

AIM

To study among men with MetS whether subjects with three, four, or five MetS variables or different estimated 10-year CVD risk differ in oxLDL and arterial elasticity.

METHODS

OxLDL was assessed by a capture ELISA and arterial elasticity by a radial artery tonometer among 120 men with MetS. Ten-year CVD risk was calculated for those without CVD or statin medication by FINRISK and SCORE at the actual age and at the extrapolated age of 60. Results. High-risk subjects by FINRISK and SCORE had impaired arterial elasticity. In addition, high-risk subjects by FINRISK at the extrapolated age had elevated oxLDL levels. The number of MetS variables did not associate with arterial elasticity or oxLDL.

CONCLUSION

Among men with MetS, estimation of 10-year CVD risk, especially when extrapolated to age 60, seems to differentiate subjects with respect to markers of subclinical atherosclerosis. Trial registration. ClinicalTrials.gov NCT01119404.

Cardio-ventilatory coupling in young healthy resting subjects

In this work, cardio-ventilatory coupling (CVC) refers to the statistical relationship between the onset of either inspiration (I) or expiration (E) and the timing of heartbeats (R-waves) before and after these respiratory events. CVC was assessed in healthy, young (<45 yr), resting, supine subjects (n = 19). Four intervals were analyzed: time from I-onset to both the prior R-wave (R-to-I) and the following R-wave (I-to-R), as well as time from E-onset to both the prior R-wave (R-to-E) and following R-wave (E-to-R). The degree of coupling was quantified in terms of transformed relative Shannon entropy (tRSE), and χ(2) tests based on histograms of interval times from 200 breaths. Subjects were studied twice, from 5 to 27 days apart, and the test-retest reliability of CVC measures was computed. Several factors pointed to the relative importance of the R-to-I interval compared with other intervals. Coupling was significantly stronger for the R-to-I interval, coupling reliability was largest for the R-to-I interval, and only tRSE for the R-to-I interval was correlated with height, weight, and body surface area. The high test-retest reliability for CVC in the R-to-I interval provides support for the hypothesis that CVC strength is a subject trait. Across subjects, a peak ~138 ms prior to I-onset was characteristic of CVC in the R-to-I interval, although individual subjects also had earlier peaks (longer R-to-I intervals). CVC for the R-to-I interval was unrelated to two separate measures of respiratory sinus arrhythmia (RSA), suggesting that these two forms of coupling (CVC and RSA) are independent.

Arterial elasticity in American Indian and Caucasian children, adolescents, and young adults

We compared arterial elasticity in American Indian and Caucasian children, adolescents, and young adults, and we assessed whether demographic, body composition, and ambulatory activity measures were predictive of arterial elasticity within each group. Fifty-one American Indians and 66 Caucasians between the ages of 8 and 30 years were assessed on large artery elasticity index, small artery elasticity index, body fat percentage, and daily ambulatory activity during 7 consecutive days. American Indians had a higher percentage of body fat than Caucasians (p = 0.002), whereas daily ambulatory activity measures were similar (p > 0.05). American Indians had a 16% lower large artery elasticity index (p = 0.007) and a 19% lower small artery elasticity index (p < 0.001) than Caucasians. The regression model for large artery elasticity index included average cadence (p = 0.001), fat-free mass (p < 0.001), age component (Caucasian only) (p < 0.001), and sex (p = 0.025). The regression model for small artery elasticity index included fat-free mass (p < 0.001), maximum cadence for 30 continuous minutes (p = 0.009), race (p = 0.005), and average cadence (p = 0.049). Between 8 and 30 years of age, elasticity means for the large and small arteries is lower in American Indians than in Caucasians. A smaller difference was observed in children, with a trend to a much larger difference in young adults. Furthermore, greater fat-free mass and higher daily ambulatory cadence are associated with higher arterial elasticity in both American Indians and Caucasians.

Abnormalities of vascular function in resistant hypertension

We aimed to evaluate markers of vascular dysfunction in patients with resistant hypertension (RH). A group of 144 patients (61 years, 42% women) with essential RH were divided in two groups based on ambulatory blood pressure monitoring (ABPM). True RH (72%) was considered when 24-h blood pressure (BP) was ≥ 130 and/or 80 mmHg. Otherwise, patients were classified as white coat RH (28%). Hyperemia-induced forearm vasodilation (HIFV), serum inflammatory biomarkers (hs-CRP, s-ICAM-1, s-VCAM-1, e-selectin, p-selectin and MCP-1) and large (C1) and small arterial (C2) compliance (HDI/Pulse Wave CR 2000) were determined in all individuals. In comparison with patients with white coat RH, and after adjustment for age, office systolic BP and diabetes status, those with true RH had a more impaired HIFV (201 ± 159 vs 436 ± 157%; p < 0.001), increased e-selectin (53.1 ± 29.8 vs 40.7 ± 23.5 ng/ml; p = 0.035), and MCP-1 (445 ± 120 vs 386 ± 126 ng/ml; p = 0.027). No significant differences were observed in arterial compliance. Maximal HIFV inversely correlated with urinary albumin excretion (Rho: - 0.278; p = 0.004) and with some inflammatory biomarkers (MCP-1: - 0.441; p < 0.001, e-selectin: - 0.468; p < 0.001 and p-selectin: - 0.329; p = 0.001). We conclude that true RH, diagnosed by ABPM, is associated with a more severe degree of vascular dysfunction, as measured by HIFV and serum biomarkers, whereas other types of vascular alterations, such as compliance, are not directly linked with the level of BP.

Arterial stiffness/elasticity in the contribution to progression of heart failure

Arterial stiffness/elasticity plays a major role in the pathogenesis of heart failure beyond arterial blood pressure. Arterial wave reflections are generated from the periphery of the vascular system, especially at the level of the small arteries. The pattern change of the arterial wave reflections can alter the ventricular-vascular coupling in a pathologic manner, leading to heart failure. Several noninvasive techniques are used to estimate arterial stiffness/elasticity. Small artery elasticity has important predictive value for the diagnosis of heart failure. The beneficial effect of some cardiovascular therapy on arterial stiffness/elasticity has potential to prevent or delay the progression of heart failure.

Arterial stiffness in lower limb amputees

BACKGROUND

A high carotid-femoral pulse wave velocity (PWV) has been related to increased cardiovascular morbidity and mortality, but has not been previously evaluated in amputees. The aim of this study was to compare PWV between amputees and nonamputees.

METHODS

In this cross-sectional study, data were collected from 60 male lower limb amputees and 86 male age-matched nonamputees. PWV was measured noninvasively using a Complior(®) device. All participants underwent laboratory investigations and anthropometry. The difference in PWV between amputee and nonamputees was estimated. Multivariate regression was used to adjust for differences between the groups as a result of potential confounders.

RESULTS

PWV was higher in amputees than in nonamputees (10.8 ± 1.9 m/sec versus 9.9 ± 1.8 m/sec, P = 0.008, respectively). This difference remained even after adjusting for confounding factors.

CONCLUSION

A higher PWV was demonstrated in lower limb amputees. Routine assessment of PWV may contribute to cardiovascular risk stratification in amputees.

Association of small artery elasticity with incident cardiovascular disease in older adults: the multi-ethnic study of atherosclerosis

Functional biomarkers like large artery elasticity (LAE) and small artery elasticity (SAE) may predict cardiovascular disease (CVD) events beyond blood pressure. The authors examined the prognostic value of LAE and SAE for clinical CVD events among 6,235 Multi-Ethnic Study of Atherosclerosis participants who were initially aged 45-84 years and without symptomatic CVD. LAE and SAE were derived from diastolic pulse contour analysis. During a median 5.8 years of follow-up between 2000 and 2008, 454 adjudicated CVD events occurred, including 256 cases of coronary heart disease (CHD), 93 strokes, and 126 heart failures (multiple diagnoses were possible). After adjustment for age, race/ethnicity, sex, clinic, height, heart rate, body mass index, systolic and diastolic blood pressure, use of antihypertensive and cholesterol-lowering medications, smoking, total cholesterol, high density lipoprotein cholesterol, triglycerides, diabetes, and high-sensitivity C-reactive protein, the hazard ratio for any CVD per standard-deviation increase in SAE was 0.71 (95% confidence interval: 0.61, 0.83; P < 0.0001). The lowest (stiffest) SAE quartile had a hazard ratio of 2.28 (95% confidence interval: 1.55, 3.36) versus the highest (most elastic) quartile. The net reclassification index, conditional on base risk, was 0.11. SAE was significantly associated with future CHD, stroke, and heart failure. After adjustment, LAE was not significantly related to CVD. In asymptomatic participants free of overt CVD, lower SAE added prognostic information for CVD, CHD, stroke, and heart failure events.

Is Small Artery Elasticity Decreased Prior to Intima-Media Thickening in Patients with Longstanding Rheumatoid Arthritis?

Objective.

To determine small artery elasticity (SAE) in patients with longstanding rheumatoid arthritis (RA) in comparison to healthy controls, and to investigate its relation to markers of endothelial cell activation, disease activity, joint damage, and the presence of atherosclerosis.

Methods.

Forty-nine patients with RA and 50 age- and sex-matched healthy controls were studied. Traditional cardiovascular risk factors and disease-related factors were recorded. SAE was measured noninvasively by pulse-wave analysis (PWA). Endothelial activation was assessed by measuring levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) and von Willebrand factor (vWF). Carotid intima-media thickness (IMT), as an indicator of subclinical atherosclerosis, was assessed using ultrasonography.

Results.

Patients with RA had higher body mass index, blood pressure, and triglyceride levels and were more often cigarette smokers compared to controls. SAE was decreased in RA patients compared to controls and was inversely related with age, smoking, blood pressure, vWF, sVCAM-1, high sensitivity C-reactive protein, and IMT. Presence of RA was independently related to SAE in multivariate linear regression analysis. SAE was inversely related with the Health Assessment Questionnaire score. No correlation was found between SAE and other disease activity markers and damage. IMT in patients and controls was not different.

Conclusion.

Small artery elasticity was decreased in patients with longstanding RA. The presence of RA was independently associated with SAE. Whereas IMT in patients with RA was not increased, we hypothesize that endothelial dysfunction, reflected by decreased SAE, is present prior to IMT thickening in these patients.

Long-term exposure to airborne particles and arterial stiffness: the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Increased arterial stiffness could represent an intermediate subclinical outcome in the mechanistic pathway underlying associations between average long-term pollution exposure and cardiovascular events.

OBJECTIVE

We hypothesized that 20 years of exposure to particulate matter (PM) ≤ 2.5 and 10 μm in aerodynamic diameter (PM2.5 and PM10, respectively) would be positively associated with arterial stiffness in 3,996 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) who were seen at six U.S. study sites.

METHODS

We assigned pollution exposure during two decades preceding a clinical exam (2000-2002) using observed PM10 from monitors nearest participants' residences and PM10 and PM2.5 imputed from a space-time model. We examined three log-transformed arterial stiffness outcome measures: Young's modulus (YM) from carotid artery ultrasound and large (C1) and small (C2) artery vessel compliance from the radial artery pulse wave. All associations are expressed per 10 μg/m3 increment in PM and were adjusted for weather, age, sex, race, glucose, triglycerides, diabetes, waist:hip ratio, seated mean arterial pressure, smoking status, pack-years, cigarettes per day, environmental tobacco smoke, and physical activity. C1 and C2 models were further adjusted for heart rate, weight, and height.

RESULTS

Long-term average particle exposure was not associated with greater arterial stiffness measured by YM, C1, or C2, and the few associations observed were not robust across metrics and adjustment schemes.

CONCLUSIONS

Long-term particle mass exposure did not appear to be associated with greater arterial stiffness in this study sample.

Predictors of large and small artery elasticity in healthy subjects from 9 to 89 years old

BACKGROUND

We identified demographic variables, cardiovascular risk factors, and ambulatory activity measures that predict large and small artery elasticity in apparently healthy subjects between 9 and 89 years of age.

METHODS

A total of 480 subjects were assessed on large artery elasticity index (LAEI), small artery elasticity index (SAEI), demographic measures, cardiovascular risk factors, and daily ambulation during 7 consecutive days. All possible regression and Mallow's C(p) were used to select multivariate models for prediction of LAEI and SAEI.

RESULTS

In subjects 20 years of age and younger, LAEI model (R(2) = 0.25, P < 0.001) included age, average ambulatory cadence, and obesity. SAEI model (R(2) = 0.39, P < 0.001) contained body mass index (BMI), maximum daily ambulatory cadence for 30 continuous min, age, and total ambulatory strides. In subjects between 21 and 50 years, LAEI model (R(2) = 0.41, P < 0.001) included systolic blood pressure (SBP), gender, race, and diastolic blood pressure (DBP). SAEI model (R(2) = 0.42, P < 0.001) contained gender, BMI, DBP, race, dyslipidemia, and SBP. In subjects older than 50 years, LAEI model (R(2) = 0.54, P < 0.001) included SBP, gender, age, and BMI. SAEI model (R(2) = 0.45, P < 0.001) contained gender, age, BMI, DBP, current smoking, and SBP.

CONCLUSIONS

Daily ambulatory activity, particularly cadence of 30 continuous min of ambulation, is positively associated with arterial elasticity in children and adolescents. In contrast, the predominant factors related to the decline in arterial elasticity in adults are blood pressure and age.

Association of serum cystatin C with pulse wave velocity, but not pressure wave reflection, in subjects with normal renal function or mild chronic kidney disease

BACKGROUND

This prospective cross-sectional study was conducted to clarify whether serum cystatin C levels might be associated with not only arterial stiffness, but also the pressure wave reflection, in middle-aged Japanese subjects with normal renal function or mild chronic kidney disease (CKD) (stage 1 or 2 CKD) (i.e., creatinine-based estimate of the glomerular filtration rate (eGFRcr) > or =60 ml/min/1.73 m(2) plus a result of the urine dipstick test for proteinuria of <1+).

METHODS

In 2,904 Japanese subjects (45 +/- 9 years old), the brachial-ankle pulse wave velocity (baPWV), radial augmentation index adjusted to a heart rate of 75 beats/min (rAI75), and serum cystatin C levels were measured.

RESULTS

Multivariate linear regression analysis demonstrated that the serum cystatin C levels were significantly correlated with the baPWV (standardized coefficient = 0.04, P < 0.01) even after adjustments for confounding variables, but not with the AI75 (standardized coefficient = 0.01, P = 0.71). adjusted values of the baPWV, but not those of rAI75, were higher in subjects with serum cystatin C levels in the highest tertile than in those with serum cystatin levels in the intermediate or lowest tertile.

CONCLUSION

In middle-aged Japanese subjects with normal renal function or mild CKD (stage 1 or 2 CKD) (eGFRcr >60 ml/min/1.73 m(2) plus a result of the urine dipstick test for proteinuria of <1+), the serum cystatin C levels may reflect facet of cardiovascular risk associated with arterial stiffness, but not that associated with the pressure wave reflection.

Relation of Arterial Properties to Left Ventricular Hypertrophy in Hypertensive Adults: Focus on Gender-Related Differences

Background: Although gender-related differences in ventricular remodeling and arterial stiffness have been described, the impact of gender on the association between vascular compliance and left ventricular hypertrophy (LVH) has not been investigated. The current study was designed to determine the gender-related differences in the association between echographically determined LVH measures and arterial stiffness in hypertensive men and women. Methods: In the current study, 104 hypertensive participants (61 men and 43 women) were enrolled. Large artery elasticity index (LAEI) and small artery elasticity index (SAEI) were determined using pulse wave contour analysis (HDI CR 2000, Eagan, Minnesota). Left ventricular hypertrophy parameters including intraventricular septum thickness (IVST), posterior wall thickness (PWT), and left ventricular mass index (LVMI) were assessed echographically. Results: Hypertensive male versus female were similar in terms of age, body mass index (BMI), blood pressure, concomitant medications, and cardiovascular risk factors. Left ventricular mass index was significantly, inversely associated with IVST (r = —.32, P = .01), PWT (r = —.32, P = .01), and LVMI (r = —.28, P = .03) in men and significantly, inversely associated with IVST (r = —39, P = .01), PWT (r = —.42, P = .005), LVMI (r = —.54, P < .0001) in women. Small artery elasticity index was significantly, inversely associated with LVMI (r = —0.36, P = .02) in women only. In regression analysis, LAEI explained more variability than SAEI and was an independent predictor of LVH parameters in hypertensive men and women. Conclusions: Compliance of large arteries is potentially an independent predictor of LVH in hypertensive men and women. Therefore, arterial compliance is being considered an important tool in predicting LVH in hypertensive participants.

Cardiovascular risk factors and arterial rigidity are similar in asymptomatic normocalcemic and hypercalcemic primary hyperparathyroidism

OBJECTIVE

It is still uncertain whether mild primary hyperparathyroidism (PHPT) carries the same risk for increased cardiovascular (CV) morbidity as the more severe symptomatic form. In recent years, the even more subtle normocalcemic (NC) variant is being increasingly recognized. We sought to compare the prevalence of CV risk factors in patients with NC- and hypercalcemic (HC)-PHPT, and to examine whether they differ on a battery of non-invasive vascular parameters. DESIGN/SUBJECTS/METHODS: A retrospective study of two cohorts of patients with PHPT in a referral center: 32 subjects with NC-PHPT and 81 subjects with HC-PHPT, compared for the presence of clinical and biochemical risk factors, and CV morbidity. Non-invasive parameters of arterial stiffness (augmentation index; pulse wave velocity; and vascular compliance indices, C1 and C2) were extracted from the data of gender- and age-matched subsets of these patients, and were related to those of a group of matched control subjects.

RESULTS

Despite a similar prevalence of hypertension (approximately 62%), hyperlipidemia (approximately 30%), and impaired glucose metabolism in both PHPT groups, CV or cerebrovascular disease was more common in the HC-PHPT group (24.7 vs 3.1%, P=0.007). Arterial stiffness parameters did not differ in the three groups, and were unrelated to serum calcium or parathyroid hormone concentration.

CONCLUSIONS

NC-PHPT and HC-PHPT subjects exhibit similar high rates of traditional CV risk factors, and have comparable indices of arterial stiffness. The lower clinical CV morbidity observed with NC-PHPT remains unexplained, and requires confirmation. Until then, the CV risk associated with NC-PHPT should not be underestimated.

Cardiovascular autonomic neuropathy, HDL cholesterol, and smoking correlate with arterial stiffness markers determined 18 years later in type 1 diabetes

OBJECTIVE To examine the relationship between cardiovascular autonomic neuropathy and pulse waveform analysis (PWA) measures of arterial stiffness in a childhood-onset type 1 diabetes population. RESEARCH DESIGN AND METHODS Cardiac autonomic nerve function was measured in the baseline examination of the Pittsburgh Epidemiology of Diabetes Complications Study of childhood-onset type 1 diabetes by heart rate variability (R-R interval) during deep breathing and expressed as expiration-to-inspiration (E/I) ratio. Other cardiovascular and diabetes factors were also assessed. PWA was performed using SphgymoCor Px on 144 participants at the 18-year follow-up examination. Univariate and multivariate analyses for associations between baseline nerve function and other cardiovascular and diabetes-related factors were performed for augmentation index (AIx), augmentation pressure (AP), and subendocardial viability ratio (SEVR), a surrogate marker of myocardial perfusion. RESULTS E/I ratio correlated negatively with both AIx (r = -0.18, P = 0.03) and AP (r = -0.32, P < 0.001) and positively with SEVR (r = 0.47, P < 0.001) univariately. Lower baseline E/I ratio, HDL cholesterol, and a history of smoking were associated with higher follow-up (18 years later) AIx and AP and lower SEVR in multivariate analyses. Higher baseline HbA(1) was also associated with higher AP and lower SEVR multivariately. CONCLUSIONS Cardiovascular autonomic neuropathy is associated with increased arterial stiffness measures and decreased estimated myocardial perfusion in those with type 1 diabetes some 18 years later. This association persists after adjustment for potential confounders as well as for baseline HbA(1), HDL cholesterol, and smoking history, which were also associated with these PWA measures.

Relationship of low birth weight to pulsatile arterial function in asymptomatic younger adults: the Bogalusa Heart Study

BACKGROUND

Low birth weight, an indicator of intrauterine growth restriction, is associated with adult cardiovascular (CV) disease, type 2 diabetes, and adverse levels of CV risk factors. Impaired pulsatile arterial function is also an independent predictor of early vascular damage and related CV outcome. However, information is scant regarding the influence of low birth weight on pulsatile arterial function.

METHODS

The study cohort consisted of 538 black and white subjects (29% black, 42% male) aged 18-44 years (mean 36.7 years) enrolled in the Bogalusa Heart Study. Subjects were categorized into low birth weight and normal birth weight. Pulsatile arterial function was assessed in terms of large artery compliance, small artery compliance, and systemic vascular resistance by noninvasive radial artery pressure pulse contour analysis.

RESULTS

Blacks and females had significantly lower birth weight compared to their counterparts. Low vs. normal birth weight group had lower large artery compliance (13.3 ml/mm Hg x 10 vs. 15.5 ml/mm Hg x 10, P = 0.0002). Further, after adjusting for age, race, and sex, the large artery compliance increased across quartiles of increasing birth weight specific for race, sex, and gestational age (P for trend = 0.03). In multivariate regression model, adding race, sex, age, body surface area, systolic blood pressure, diastolic blood pressure, triglycerides/high-density lipoprotein cholesterol ratio one by one, the effect was attenuated but significant (beta = -0.067, P = 0.033).

CONCLUSIONS

The observed deleterious association of low birth weight on arterial wall dynamics in asymptomatic younger adults may account in part for the adverse CV risk in the Bogalusa sample.

Insight into the dicrotic notch in photoplethysmographic pulses from the finger tip of young adults

This study aims to investigate arterial stiffness in selected young adults by non-invasively determining the characteristics of the photoplethysmographic dicrotic notch. A total of 15 volunteers participated in this study, divided into four groups by age and gender. Contour analysis was applied to analyse the photoplethysmographic dicrotic notch, including time-related and height-related parameters. The height of reflected wave, mirrored by the notch relative amplitude (NRA), was found to be significantly larger in the older group compared to the younger group (p = 0.016). The timing of the reflected wave, measured by three parameters, i.e. notch index (NI), notch latency (NL) and peak-to-notch latency (PTNL), significantly increased in the female group compared to the male group (all p < 0.02). The results confirm that arterial stiffness occurs in young adults, and demonstrate that a difference of arterial stiffness exists between young male and female. This study indicates that examining the characteristic notch of the PPG pulse could help in identifying differences of vascular activities.

Pulse wave velocity is more closely associated with cardiovascular risk than augmentation index in the relatively low-risk population

Pulse wave velocity (PWV) and augmentation index (AI) are both indirect indicators of arterial stiffness, which is an independent predictor of morbidity and mortality in cardiovascular diseases. The aim of this study was to assess the association between carotid AI (CAI), carotid-femoral PWV (CFPWV), and Framingham risk score (FRS), and to evaluate the factors determining CAI and CFPWV. Carotid AI and CFPWV were measured by applanation tonometry in 177 consecutive subjects without evidence of significant cardiovascular disease. Correlations between CAI and FRS and CFPWV and FRS were analyzed and major determinants of CAI and CFPWV were assessed. The mean age was 60.5 +/- 11.9 years and 112 (63%) of study patients were men. There was a significant association between CFPWV and FRS (r = 0.417, P < 0.001) and a weaker but also significant relation between CAI and FRS (r = 0.267, P < 0.001). CFPWV was significantly related to FRS in both men and women (P < 0.001 in both sexes), whereas the relation between CAI and FRS was significant only in women (P < 0.001). Our results suggest that CFPWV may be associated with CVD risk irrespective of sex, whereas CAI may be associated with CVD risk in women only.

Comprehensive noninvasive arterial vascular evaluation

Noninvasive evaluation of the health of the vasculature is an increasingly important approach to identifying individuals at risk for cardiovascular morbid events. Vascular health assessment involves functional and structural examination of the large and small arteries. Endothelial dysfunction, which alters small artery function, is a key contributor to progressive structural vascular changes. Ultrasonography of conduit arteries and aortic pulse-wave velocity provide information limited to structural changes in large arteries. Comprehensive assessment of the large and small arteries is best carried out by pulse-contour analysis. This can provide insight into functional and structural abnormalities in the small as well as the large arteries, and may be useful in monitoring response to therapy.

Vascular function, inflammation, and variations in cardiac autonomic responses to particulate matter among welders

Patients with health conditions associated with impaired vascular function and inflammation may be more susceptible to the adverse health effects of fine particulate (particulate matter with a mass median aerodynamic diameter of </=2.5 mum (PM(2.5))) exposure. In 2006, the authors conducted a panel study to investigate directly whether vascular function and inflammation (assessed by C-reactive protein) modify PM(2.5)-associated reductions in heart rate variability among 23 young male workers (mean age, 40 years) from Massachusetts. Concurrent 24-hour ambulatory electrocardiogram and personal PM(2.5) exposure information was collected over a total of 36 person-days, including either or both welding and nonwelding days. Linear mixed models were used to examine the 5-minute standard deviation of normal-to-normal intervals (SDNN) in relation to the moving PM(2.5) averages in the preceding 1-4 hours. C-reactive protein levels and 3 measures of vascular function (augmentation index, mean arterial pressure, and pulse pressure) were determined at baseline. The authors observed an inverse association between the 1-hour PM(2.5) and 5-minute SDNN. Greater SDNN declines were observed among those with C-reactive protein (P(interaction) < 0.001) and augmentation index (P = 0.06) values at or above the 75th percentile and pulse pressure values below the 75th percentile (P < 0.001). Systemic inflammation and poorer vascular function appear to aggravate particle-related declines in heart rate variability among workers.

Noninvasive pulse wave analysis for the determination of central artery stiffness

Central artery stiffness predicts cardiovascular structural damage and clinical outcome. It is controversial whether central artery stiffness can be determined by noninvasive measurements. We compared noninvasive determination of central artery stiffness obtained from applanation tonometry of the peripheral radial artery waveform with invasive measurements of the ratio of pulse-pressure-to-stroke-volume. A total of 112 invasive measurements of the ratio of pulse-pressure-to-stroke-volume and noninvasive determinations of central artery stiffness were performed in 49 patients on the intensive care unit. In 13 out of 112 attempts of noninvasive measurements (12%) radial pulse could not be obtained using applanation tonometry because of cardiac arrhythmia or radial pulse could not be detected. These 13 failing noninvasive measurements were attempted in 7 patients. In the remaining cases we found a significant correlation between noninvasively obtained central artery stiffness and invasive measurements of the ratio of pulse-pressure-to-stroke-volume (Spearman r=0.40; p<0.0001). The association between invasive and noninvasive measurements was confirmed using Bland-Altman plots. Furthermore, a norepinephrine-induced increase of arterial stiffness was detected both invasively and noninvasively. Noninvasive determination of central artery stiffness obtained from peripheral radial artery waveform should be useful in clinical practice although it cannot be performed in every patient.

Family history of hypertension and arterial elasticity characteristics in healthy young people

Family history of hypertension is a primary predictor of high blood pressure (BP). This study attempted to determine whether there is a gradual increase in BP and an early change in arterial elasticity characteristics between young healthy individuals with or without a family history of hypertension and whether or not this increase is apparent in males as well as in females. A total of 270 normotensive healthy individuals (112 men and 158 women, aged 16 to 30 years) with or without a family history of hypertension, participated in conventional BP measurement and completed questionnaires covering basic information and a detailed family history of cardiovascular disease. Large arterial (capacitive) compliance (C1) and small arterial (oscillatory or reflective) compliance (C2) were derived from HDI/PulseWave CR-2000 (Hypertension Diagnostics, Minneapolis, USA). Based on family history information about parents and grandparents, three groups were formed: subjects with at least one hypertensive parent (group A), subjects with only hypertensive grandparents (group B), and subjects with normotensive parents and grandparents (group C). Men in group A had lower C1 and C2 along with higher systolic BP (SBP), diastolic BP (DBP), and heart rate than men in group C. Those in group B had intermediate C1, C2 and BP levels. C1 had a linear relationship with SBP, DBP, and heart rate. In the logistic regression model of family history of hypertension, C2 was lower in young normotensive males with parental hypertension (B = -0.315, exp B = 0.73, p = 0.03), independently of SBP, DBP, and heart rate. Among females, subjects with parental hypertension had higher systolic, mean arterial pressure, and pulse pressure (p < 0.05), and there were no significant differences in C1 and C2 between those with and those without parental hypertension. In conclusion, compared with normotensive offspring of normotensive parents, normotensive offspring of hypertensive parents had increased BP and impaired arterial properties, namely large and small arterial compliance as measured noninvasively by HDI. These differences were exhibited conspicuously in men but not in women. Alteration in arterial function in young non-hypertensive subjects may be a risk factor for hypertension and may contribute to the progression to hypertension later in life.