Non-invasive assessment of arterial stiffness using oscillometric blood pressure measurement

The Cardiovascular Benefits of Dark Chocolate Supplementation before High-Intensity Resistance Exercise in the Early Follicular and Mid-Luteal Phases of the Menstrual Cycle

BACKGROUND

Dark chocolate, rich in flavanols, may support vascular health by reducing arterial stiffness and blood pressure across menstrual phases. This study examined the effects of 85% dark chocolate on nitric oxide (NO) levels and vascular function during high-intensity resistance exercise in healthy women across the early follicular and mid-luteal phases.

METHODS

Thirty-one healthy women (aged 20-30 years) with regular menstrual cycles completed a randomized, crossover study (conducted at National Chung Cheng University, Sep-Dec 2023). Participants consumed either 85% dark chocolate or milk chocolate (1 g/kg body weight) before high-intensity resistance exercise during the early follicular (days 2-5) and mid-luteal (days 18-24) phases of two menstrual cycles. Finger-toe pulse wave velocity (ftPWV), arterial stiffness, blood pressure, and plasma NO levels were measured at rest, 2 h after chocolate consumption (baseline), immediately post-exercise (T0), and at 60 (T60) and 120 (T120) minutes post-exercise.

RESULTS

Dark chocolate supplementation significantly increased NO levels and reduced systolic blood pressure (SBP), ftPWV, and arterial pressure volume index (API) (p < 0.05) compared to milk chocolate across both menstrual phases. During the early follicular phase, dark chocolate also attenuated exercise-induced increases in arterial stiffness and blood pressure (p < 0.05).

CONCLUSION

85% dark chocolate supplementation may reduce the negative vascular effects of high-intensity resistance exercise, particularly by lowering blood pressure, arterial stiffness, and API, especially in the early follicular phase. These findings suggest that dark chocolate could be a practical, non-pharmacological intervention for improving cardiovascular health in women.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT06908941. Registered 19 March 2025 - Retrospectively registered, https://clinicaltrials.gov/study/NCT06908941 .

The Feasibility of Measuring Central Blood Pressure with Bedside Echocardiography: An Observational Cross-Sectional Study

RATIONALE AND OBJECTIVES

Central arterial blood pressure (CBP) is considered a more valuable prognostic marker of major cardiovascular diseases than peripheral blood pressure. Non-invasive evaluation of central aortic pressure by Doppler echocardiography is a hopeful tool, avoiding many complications of invasive catheter strategy and diminishing time and costs.

METHODS

A total of 118 patients were referred for elective cardiac catheterization at the Cardiovascular Medicine Department, Mansoura University. Standard transthoracic echocardiography was simultaneously performed during invasive measurement of the central aortic pressure in the cardiac catheterization lab.

RESULTS

A significant correlation existed between invasive systolic, diastolic, and mean aortic pressure and aortic deceleration time, with P-values of 0.0003, 0.0002, and 0.0002, respectively. A significant correlation was also found between invasive systolic, diastolic, and mean aortic pressure and aortic Velocity Time Integral (VTI), with P-values of 0.006, 0.0004, and 0.0004, respectively. A significant and more reliable equation existed to calculate mean or diastolic central blood pressure by transthoracic aortic deceleration time values.

CONCLUSION

Central aortic pressure can be measured non-invasively using Doppler echocardiographic parameters: Left ventricular Mass (LVM), aortic deceleration time, and velocity time integral during routine echocardiography examination using rational equations. This represents a promising technique for further research.

Profile of Nagasaki Islands Study (NaIS): A Population-based Prospective Cohort Study on Multi-disease

In an aging society, it is important to visualize the conditions of people living with diseases or disabilities, such as frailty and sarcopenia, and determine the environmental and genetic factors underlying such conditions. Atherosclerosis and arterial stiffness are key conditions between these factors and noncommunicable diseases. In 2014, we launched a population-based prospective open-cohort study, the Nagasaki Islands Study (NaIS), which was conducted in Goto City, located in the remote islands of Nagasaki Prefecture, Japan, mostly involving middle-aged and older residents. We conducted our own health checkups along with the annual standardized checkups organized by the municipality; recruited study participants; and started to follow them for vital status (death), migration, and occurrence of diseases, such as myocardial infarction, stroke, fracture, and human T-cell leukemia virus type 1 (HTLV-1)-associated uveitis. Our checkups were conducted as baseline surveys in different areas of Goto City during the fiscal years 2014-2016, secondary surveys during 2017-2019, and tertiary surveys since 2021, consisting of medical interviews, physical examinations, blood and urine tests, body composition measurements, osteoporosis screening, arterial stiffness measurements, carotid ultrasonography, and dental examination. A total of 4,957 residents participated in either the baseline or secondary surveys and were followed; 3,594 and 3,364 residents (aged 27-96 and 28-98 years) participated in the baseline and secondary surveys, respectively. In conclusion, the NaIS has been undertaken to reveal the influence of aging and risk factors of noncommunicable diseases and disabilities, with an aim to contribute towards better healthcare in the future.

Photoplethysmography for the Assessment of Arterial Stiffness

This review outlines the latest methods and innovations for assessing arterial stiffness, along with their respective advantages and disadvantages. Furthermore, we present compelling evidence indicating a recent growth in research focused on assessing arterial stiffness using photoplethysmography (PPG) and propose PPG as a potential tool for assessing vascular ageing in the future. Blood vessels deteriorate with age, losing elasticity and forming deposits. This raises the likelihood of developing cardiovascular disease (CVD), widely reported as the global leading cause of death. The ageing process induces structural modifications in the vascular system, such as increased arterial stiffness, which can cause various volumetric, mechanical, and haemodynamic alterations. Numerous techniques have been investigated to assess arterial stiffness, some of which are currently used in commercial medical devices and some, such as PPG, of which still remain in the research space.

Gender and age disparities in small-to-medium arterial stiffness among the Chinese population

BACKGROUND AND AIMS

Arterial pressure-volume index (API) is a non-invasive tool for assessing small-to-medium-sized arterial stiffness. This study aimed to investigate the potential age- and sex-related differences in the API and explore the practical implications of such differences.

METHODS AND RESULTS

The study analysed 7620 subjects for whom API measurements were available. Linear regression and restrictive cubic spline models were used to investigate the associations between potential risk conditions and the API. Additionally, this study employed a backward stepwise regression method to identify the independent factors associated with a high API. Middle-aged to older women had higher API values and a higher prevalence of high API than men in the same age group. However, the opposite was observed among younger individuals, with women having lower API values than men. This study also identified a J-shaped relationship between API and age, where API values began to increase at a certain age and rapidly increased after that. In women, the API started to increase at 31 years of age and rapidly increased after 54 years of age. In men, the API started to increase at 38 years of age, followed by a rapid increase after 53 years of age.

CONCLUSION

This study's observation of a significant age-sex interaction in small-to-medium-sized arterial stiffening offers a valuable explanation for cardiovascular disease risk and provides important parameters for using API measurements to evaluate such risk.

Development and clinical validation of a miniaturized finger probe for bedside hemodynamic monitoring

Our aim is to develop a blood pressure (BP) measurement technology that could be integrated into a finger-worn pulse oximeter, eliminating the need for a brachial cuff. We present a miniature cuffless tonometric finger probe system that uses the oscillometric method to measure BP. Our approach uses a motorized press that is used to apply pressure to the fingertip to measure BP. We verified the functionality of the device in a clinical trial (n = 43) resulting in systolic and diastolic pressures ((mean ± SD) mmHg) of (-3.5 ± 8.4) mmHg and (-4.0 ± 4.4) mmHg, respectively. Comparison was made with manual auscultation (n = 26) and automated cuff oscillometry (n = 18). In addition to BP, we demonstrated the ability of the device to assess arterial stiffness (n = 18) and detect atrial fibrillation (n = 6). We were able to introduce a sufficiently small device that could be used for convenient ambulatory measurements with minimal discomfort.

Computation of Vascular Parameters: Implementing Methodology and Performance Analysis

This paper presents the feasibility of automated and accurate in vivo measurements of vascular parameters using an ultrasound sensor. The continuous and non-invasive monitoring of certain parameters, such as pulse wave velocity (PWV), blood pressure (BP), arterial compliance (AC), and stiffness index (SI), is crucial for assessing cardiovascular disorders during surgeries and follow-up procedures. Traditional methods, including cuff-based or invasive catheter techniques, serve as the gold standard for measuring BP, which is then manually used to calculate AC and SI through imaging algorithms. In this context, the Continuous and Non-Invasive Vascular Stiffness and Arterial Compliance Screener (CaNVAS) is developed to provide continuous and non-invasive measurements of these parameters using an ultrasound sensor. By driving 5 MHz (ranging from 2.2 to 10 MHz) acoustic waves through the arterial walls, capturing the reflected echoes, and employing pre-processing techniques, the frequency shift is utilized to calculate PWV. It is observed that PWV measured by CaNVAS correlates exponentially with BP values obtained from the sphygmomanometer (BPMR-120), enabling the computation of instantaneous BP values. The proposed device is validated through measurements conducted on 250 subjects under pre- and post-exercise conditions, demonstrating an accuracy of 95% and an average coefficient of variation of 12.5%. This validates the reliability and precision of CaNVAS in assessing vascular parameters.

Threshold values of brachial cuff-measured arterial stiffness indices determined by comparisons with the brachial-ankle pulse wave velocity: a cross-sectional study in the Chinese population

Background

Arterial Velocity-pulse Index (AVI) and Arterial Pressure-volume Index (API), measured by a brachial cuff, have been demonstrated to be indicative of arterial stiffness and correlated with the risk of cardiovascular events. However, the threshold values of AVI and API for screening increased arterial stiffness in the general population are yet to be established.

Methods

The study involved 860 subjects who underwent general physical examinations (M/F = 422/438, age 53.4 ± 12.7 years) and were considered to represent the general population in China. In addition to the measurements of AVI, API and brachial-ankle pulse wave velocity (baPWV), demographic information, arterial blood pressures, and data from blood and urine tests were collected. The threshold values of AVI and API were determined by receiver operating characteristic (ROC) analyses and covariate-adjusted ROC (AROC) analyses against baPWV, whose threshold for diagnosing high arterial stiffness was set at 18 m/s. Additional statistical analyses were performed to examine the correlations among AVI, API and baPWV and their correlations with other bio-indices.

Results

The area under the curve (AUC) values in ROC analysis for the diagnosis with AVI/API were 0.745/0.819, 0.788/0.837, and 0.772/0.825 (95% CI) in males, females, and all subjects, respectively. Setting the threshold values of AVI and API to 21 and 27 resulted in optimal diagnosis performance in the total cohort, whereas the threshold values should be increased to 24 and 29, respectively, in order to improve the accuracy of diagnosis in the female group. The AROC analyses revealed that the threshold values of AVI and API increased markedly with age and pulse pressure (PP), respectively.

Conclusions

With appropriate threshold values, AVI and API can be used to perform preliminary screening for individuals with increased arterial stiffness in the general population. On the other hand, the results of the AROC analyses imply that using threshold values adjusted for confounding factors may facilitate the refinement of diagnosis. Given the fact that the study is a cross-sectional one carried out in a single center, future multi-center or follow-up studies are required to further confirm the findings or examine the value of the threshold values for predicting cardiovascular events.

Relative contributions of arterial stiffness to cardiovascular disease risk score in Chinese women in framingham and China-PAR model

Background

Arterial stiffness played an important role in the development of cardiovascular disease (CVD) events. The aim of this study was to verify the relative importance of arterial stiffness for different CVD risk scores in a large sample of Chinese women.

Methods

We measured arterial velocity pulse index (AVI) and CVD risk scores in 2220 female participants (mean age 57 years). Framingham Risk Score (FRS), and the prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR) were used to estimate CVD risk, respectively. The relationships between AVI and risk scores were investigated by linear regressions and restricted cubic spline (RCS) analysis. To determine the relative importance of AVI in predicting CVD risk scores, random forest analysis was used.

Results

There was a significant positive correlation between AVI and FRS, China-PAR in all subgroup groups stratified by age, blood pressure and BMI. AVI showed higher importance in predicting CVD risk scores in FRS model, compared with these traditional risk factors. In China-PAR model, although AVI was not as predictive as SBP, it had better predictive power than many known risk factors such as lipids. Furthermore, AVI had significant J-shaped associations both with FRS and China-PAR scores.

Conclusions

AVI was significantly associated with CVD risk score. In FRS and China-PAR model, AVI showed relatively high importance in predicting CVD risk scores. These findings may support the use of arterial stiffness measurements in CVD risk assessment.

Arterial Stiffness, Body Mass Index and Cardiovascular Disease Risk in Chinese Females at Various Ages

Background

This study investigated the correlation in parameters of arterial stiffness and cardiovascular disease (CVD) risk on age and body mass index (BMI) in Chinese females.

Methods

This cross-sectional study enrolled 2220 females. Arterial stiffness was assessed by the measurement of arterial velocity pulse index (AVI) and arterial pressure volume index (API). Individual 10-year cardiovascular risk was calculated for each patient using the Framingham cardiovascular risk score (FCVRS).

Results

API and AVI had a significant J-shaped relationship with age. Beginning at the age of 30 years, the API started to increase, while after 49 years, the increase in API was even steeper. AVI increased from the age of 32 years, and increased more rapidly after 56 years. The linear association between API and BMI following adjustment for age was significant ( β = 0.324, 95% CI 0.247-0.400, p < 0.001). In the total study cohort, FCVRS scores increased by 0.16 scores for every 1 kg/ m 2 increase in BMI and by 0.11 scores for each 1 value increase in API in the age adjusted model.

Conclusions

API and BMI correlate with 10-year cardiovascular risk at various ages in females. Regardless of age, overweight females have a higher risk of increased API. Therefore API can be used for the early detection of CVD so that preventive therapy can be instituted in these high risk patients.

Clinical Trial Registration

Registered on the official website of the China Clinical Trial Registration Center (20/08/2020, ChiCTR2000035937).

Increased arterial pressure volume index and cardiovascular risk score in China

BACKGROUND AND OBJECTIVE

The new non-invasive arterial stiffness indices, arterial pressure volume index (API) is explored as a novel marker of residual stress in the wall of the peripheral muscular arteries at zero-stress state in clinical settings. The present study aimed to study the association of API with cardiovascular disease (CVD) risk in China (China-PAR).

METHODS

According to China-PAR score, participants were divided into three groups: low risk (< 5%), medium risk (5-9.9%), and high risk (≥ 10.0%). API ≥ 31 was defined as high API, and the incidences of high API were compared. Logistic regression models were used to analyze the risk factors of high API and high risk China-PAR categories. The association between China-PAR and API was analyzed by restrictive cubic spline.

RESULTS

The study included 4311 participants. After adjustments for confounding factors, high API was independent factor associated with high risk China-PAR categories, and the probability of high API was 1.366 times higher than that in normal API subjects. While, the independent factors associated with high API were BMI, blood pressure and heart rate. Furthermore, API had a significant U-shaped association with China-PAR. CVD risk was lowest with API of 19 units, the fastest increase at 26 units and the flattest starting point at 59 units.

CONCLUSION

API, an indicator of arterial stiffness and residual stress, had a U-shaped association with China-PAR score and might play an important role in predicting CVD risk in Chinese natural populations.

Upper-Arm SBP Decline Associated with Repeated Cuff-Oscillometric Inflation Significantly Correlated with the Arterial Stiffness Index

We evaluated the clinical significance of the new non-invasive vascular indices to explore their potential utility using repeated cuff-oscillometric inflation. In 250 consecutive outpatients, we performed a cross-sectional, retrospective, single-center, observational study to investigate sequential differences in arterial stiffness using blood pressure, arterial velocity pulse index (AVI), and arterial pressure volume index (API) with repeated measurements. Males accounted for 62.7% of the patients, and the mean age was 68.1 ± 12.1 years. The mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the first reading in repeated measurements were 133.07 ± 21.20 mmHg and 73.94 ± 13.56 mmHg, respectively. The mean AVI and API were 23.83 ± 8.30 and 31.12 ± 7.86, respectively. In each measurement of these parameters, although DBP and AVI did not show significant changes throughout repeated measurements, SBP and API decreased significantly according to the measurement orders. Furthermore, changes in SBP and API were significantly correlated in several of the models. In this study, it was concluded that upper-arm SBP decline associated with repeated cuff-oscillometric inflation was significantly correlated with the arterial stiffness index. The findings of this study will allow clinicians to easily recognize the progression of atherosclerosis through regular, routine practice. In conclusion, this study suggests that changes in repeated SBP measurements may be predictive of arterial stiffness and atherosclerosis.

Association of Arterial Stiffness Indices with Framingham Cardiovascular Disease Risk Score

Purpose

The new non-invasive arterial stiffness indices, arterial velocity pulse index (AVI) and arterial pressure volume index (API) are known to be associated with cardiovascular disease risk. The present study aimed to examine the "dose-response" associations between AVI, API and Framingham cardiovascular disease risk score (FCVRS).

Methods

This survey included individuals with arterial stiffness indices collected at age 18 years and older. We used Pearson's correlation coefficients and multivariate linear analyses to evaluate associations of AVI and API to other variables. The associations between FCVRS and AVI, API were analyzed by restrictive cubic spline.

Results

4311 people were included in the full study population, including 2091 males and 2220 females. In restricted cubic spline regression models, AVI or API had significant U-shaped associations with FCVRS, with the lowest risk score of cardiovascular disease was 8 units or 18 units, respectively. After AVI increased to 12 units, FCVRS increased rapidly until AVI was 27 units, and the FCVRS increased relatively flat afterward. For API, results were similar. When API increased to 23 units, the FCVRS increased rapidly, and after API was 52 units, FCVRS increased relatively flat.

Conclusions

AVI or API had U-shaped associations with FCVRS. The associations may provide a new perspective for early treatment or lifestyle modifications to prevent cardiovascular diseases.

Relationships between muscle sympathetic nerve activity and novel indices of arterial stiffness using single oscillometric cuff in patients with hypertension

The arterial velocity pulse index (AVI) and arterial pressure-volume index (API) have been proposed as new arterial stiffness indices that can be measured using an oscillometric cuff. Sympathetic nerve activity (SNA) contributes to arterial stiffness via increasing vascular smooth muscle tone. However, the associations between SNA and the AVI or API are not understood. The purpose of this study was to evaluate the relationships between muscle sympathetic nerve activity (MSNA) and the AVI or API in healthy individuals and patients with hypertension (HT). Forty healthy individuals (40.1 ± 15.2 years, 8 females) (healthy group) and 40 patients with HT (60.2 ± 13.6, 18 females) (HT group) were included in this study. The AVI, API, MSNA, beat-by-beat blood pressure, and heart rate were recorded simultaneously. The AVI and API were higher in the HT group than in the healthy group (AVI, 26.1 ± 7.6 vs. 16.5 ± 4.0, p < 0.001; API, 31.2 ± 8.6 vs. 25.5 ± 7.2, p = 0.002). MSNA in the HT group was also higher than in the healthy group (p < 0.001). MSNA was correlated with the AVI, but not with the API, in both the healthy group (R = 0.52, p = 0.001) and HT group (R = 0.57, p < 0.001). MSNA was independently correlated with the AVI in multivariate analysis (ß = 0.34, p = 0.001). In conclusion, AVI, obtained by a simple and less user-dependent method, was related to the MSNA in healthy individuals and patients with HT.

Effects of high-intensity interval training on improving arterial stiffness in Chinese female university students with normal weight obese: a pilot randomized controlled trial

Background

High intensity interval training (HIIT) has been reported to exert better effects on cardiovascular fitness in obesity, but little known about the arterial stiffness (AS) in female university students with normal weight obesity (NWO). Thus, this study aimed to investigate the effects of HIIT on the body composition, heart rate (HR), blood pressure (BP), blood lipids metabolism as well as the novel parameters of propensity for AS (arterial velocity pulse index [AVI], arterial pressure volume index [API]) for female university students with NWO.

Methods

Forty female university students with NWO were randomly assigned to control group (n = 20) and HIIT group (3 bouts of 9‑min intervals at 90% of the maximal heart rate [HR_max], interspersed by 1 min rest, 5 days a week, n = 20). Tests were performed before and after 4 weeks of training. Repeated measures ANOVA and simple effect test analysis were used to analyze dependent variable changes.

Results

After 4 weeks HIIT statistically significantly improved the body composition by decreasing the body mass index, body fat percent, total body fat mass (BFM), BFM of left arm, measured circumference of left arm, and obesity degree, and increasing the total body skeletal muscle mass, protein content, total body water, fat free mass, body cell mas, and InBody score. HIIT also statistically significantly decreased the HR and BP. As for the lipid profile, HIIT obviously ameliorated the blood lipids metabolism by decreasing the levels of total cholesterol (TC), triglyceride, low-density lipoprotein, and TC/HDL, and increasing the levels of high-density lipoprotein (HDL). In addition, the AVI and API were markedly decreased via HIIT intervention.

Conclusions

HIIT produced significant and meaningful benefits for body composition, HR, BP, and blood lipids metabolism, and could decrease AS in female university students with NWO. This suggests that HIIT may effectively reduce the risk of arteriosclerosis and protect the cardiovascular function for female university students with NWO.

Trial registration ChiCTR2100050711. Registered 3 September 2021. Retrospectively registered.

Association between blood pressure and the risk of biopsy-induced endobronchial hemorrhage during bronchoscopy

BACKGROUND

Hemorrhage is one of the most common complications of bronchoscopy. Although several hemorrhage risk factors have been proposed, it remains unclear whether blood pressure affects the onset of biopsy-induced endobronchial hemorrhage.

METHODS

We conducted a retrospective cohort study of 643 consecutive adults with lung cancer over an approximately 4-year period (from January 2014 to February 2018) at a large tertiary care hospital. Patients were divided into the hemorrhage group and the non-hemorrhage group based on endobronchial biopsy (EBB) findings. The association between systolic pressure (SP), diastolic pressure (DP), mean arterial pressure (MAP), pulse pressure (PP), PP to DP ratio (PP/DP) and the risk of EBB-induced hemorrhage was evaluated using multivariate regression analysis and smooth curve fitting adjusted for potential confounding factors.

RESULTS

The EBB-induced bleeding incidence was 37.8% (243/643) in our cohort. An independent association was found between PP/PD and the EBB-induced hemorrhage risk (per 1 SD, adjusted odds ratio, 0.788; 95% confidence interval, 0.653-0.951). The multivariate regression analysis performed using quartiles of PP/DP revealed that lower level of PP/DP ratio was related to a higher risk of EBB-induced hemorrhage (P for trend <0.05) after adjustment for potential confounders. However, no association was observed between SP, DP, MAP, PP and EBB-induced hemorrhage.

CONCLUSIONS

Low PP/DP was the independent risk factor for biopsy-induced endobronchial hemorrhage during bronchoscopy in patients with lung cancer.

Effect of aerobic exercise training frequency on arterial stiffness in middle-aged and elderly females

[Purpose] This study aimed to determine the effects of aerobic exercise training frequency on arterial stiffness in postmenopausal females. [Participants and Methods] This study included 45 postmenopausal females randomly assigned to one of the following three groups: 1) low-frequency training group (aerobic exercise training twice per week); 2) high-frequency training group (aerobic exercise training four times per week); and 3) control group (no training). Each group was subjected to an 8-week intervention period. Both traditional and newer indexes were measured immediately before and after the 8-week intervention period. [Results] In the low-frequency training group, carotid-femoral pulse wave velocity and arterial velocity pulse index decreased post 8 weeks compared with those at baseline. In the high-frequency training group, carotid-femoral, brachial-ankle, and heart-brachial pulse wave velocities and arterial velocity pulse and arterial pressure-volume indexes decreased post 8 weeks compared to those at baseline. In the control group, no change in any indices post 8 weeks compared to those at baseline was observed. [Conclusion] Carotid-femoral pulse wave velocity was lower after aerobic training than before training in both the exercise groups. Thus, aerobic exercise training might have a beneficial effect on aortic stiffness, regardless of the training frequency in this population.

Enabling Wearable Pulse Transit Time-Based Blood Pressure Estimation for Medically Underserved Areas and Health Equity: Comprehensive Evaluation Study

BACKGROUND

Noninvasive and cuffless approaches to monitor blood pressure (BP), in light of their convenience and accuracy, have paved the way toward remote screening and management of hypertension. However, existing noninvasive methodologies, which operate on mechanical, electrical, and optical sensing modalities, have not been thoroughly evaluated in demographically and racially diverse populations. Thus, the potential accuracy of these technologies in populations where they could have the greatest impact has not been sufficiently addressed. This presents challenges in clinical translation due to concerns about perpetuating existing health disparities.

OBJECTIVE

In this paper, we aim to present findings on the feasibility of a cuffless, wrist-worn, pulse transit time (PTT)-based device for monitoring BP in a diverse population.

METHODS

We recruited a diverse population through a collaborative effort with a nonprofit organization working with medically underserved areas in Georgia. We used our custom, multimodal, wrist-worn device to measure the PTT through seismocardiography, as the proximal timing reference, and photoplethysmography, as the distal timing reference. In addition, we created a novel data-driven beat-selection algorithm to reduce noise and improve the robustness of the method. We compared the wearable PTT measurements with those from a finger-cuff continuous BP device over the course of several perturbations used to modulate BP.

RESULTS

Our PTT-based wrist-worn device accurately monitored diastolic blood pressure (DBP) and mean arterial pressure (MAP) in a diverse population (N=44 participants) with a mean absolute difference of 2.90 mm Hg and 3.39 mm Hg for DBP and MAP, respectively, after calibration. Meanwhile, the mean absolute difference of our systolic BP estimation was 5.36 mm Hg, a grade B classification based on the Institute for Electronics and Electrical Engineers standard. We have further demonstrated the ability of our device to capture the commonly observed demographic differences in underlying arterial stiffness.

CONCLUSIONS

Accurate DBP and MAP estimation, along with grade B systolic BP estimation, using a convenient wearable device can empower users and facilitate remote BP monitoring in medically underserved areas, thus providing widespread hypertension screening and management for health equity.

New indices of arterial stiffness correlate with disease severity and mid-term prognosis in acute decompensated heart failure

Arterial stiffness has been implicated in pathophysiology of heart failure (HF) since it is involved in the ventricular-vascular coupling. Recently, new indices obtained by a cuff oscillometric technique, the arterial velocity pulse index (AVI) for the stiffness of central arteries and the arterial pressure volume index (API) for the stiffness of peripheral arteries have been developed and validated. However, the AVI and API measurement has not been attempted in HF population. This study aimed to investigate the relationship between the AVI, API and clinical parameters and outcomes in HF patients. A prospective cohort of patients with acute decompensated HF were enrolled within 6 months, who were admitted to a tertiary referral hospital in China. Measurement of the AVI and API (AVE-1500, Shisei Datum, Tokyo, Japan) was performed on the day of admission and discharge. Patients were followed up to 6 months for the composite endpoint of all-cause death and rehospitalization for HF. A total of 127 patients were recruited for analysis (60 ± 15 years, 70% male). 80% of the patients were in New York Heart Association (NYHA) Class III or IV at admission with mean left ventricular ejection fraction (LVEF) of 34 ± 9%. During hospitalization, all patients received guideline-directed medical therapy if not contraindicated. The AVI (27.3 ± 5.0 vs. 28.6 ± 6.7, P = 0.002) and API (24.9 ± 4.9 vs. 26.0 ± 6.5, P = 0.05) were lower at discharge than at admission. By dividing the patients into mild to severe group based on systolic blood pressure (SBP) and LVEF or into tertiles according to the amino-terminal pro-brain natriuretic peptide (NT-proBNP), transmitral E velocity over mitral annular e' velocity (E/e' ratio), it was observed that the AVI increased with a higher level of NT-proBNP (P for trend < 0.001), a larger E/e' (P for trend < 0.001) and a lower LVEF (P for trend = 0.0183), while the API increased as the E/e' and systolic blood pressure became higher (both P for trend < 0.05). The improvement in AVI at discharge was correlated with LVEF (R = - 0.3024, P < 0.05) and NT-proBNP improvement (R = 0.3118, P < 0.05), while the change in API was positively correlated with SBP change (R = 0.3897, P < 0.001). In 6 months after discharge, there were 52 predefined events including 15 deaths and 44 rehospitalization for HF. Apart from the level of NT-proBNP, the AVI at discharge of ≥ 26 showed a trend of being associated with the composite outcome (HR 2.747, 95% CI 1.411-5.349, P < 0.001 for univariate analysis; HR 1.864, 95% CI 0.892-3.893, P = 0.09761 for multivariate analysis). New noninvasive arterial stiffness indices as the AVI and API reflected severity of illness and midterm prognosis in admitted HF patients. Further studies are warranted for understanding its mechanisms and developing clinical applications.

Arterial Stiffness Index and Exercise Tolerance in Patients Undergoing Cardiac Rehabilitation

Arterial stiffness contributes to the development of cardiovascular disease (CVD). However, the relationship between the arterial stiffness and exercise tolerance in CVD patients with preserved ejection fraction (pEF) and those with reduced EF (rEF) is unclear. We enrolled 358 patients who participated in cardiac rehabilitation and underwent cardiopulmonary exercise testing at Juntendo University Hospital. After excluding 195 patients who had undergone open heart surgery and 20 patients with mid-range EF, the patients were divided into pEF (n = 99) and rEF (n = 44) groups. Arterial stiffness was assessed using arterial velocity pulse index (AVI) and arterial pressure volume index (API) at rest. The patients in the pEF group were significantly older and had a higher prevalence of coronary artery disease than the rEF group. The pEF group had significantly lower AVI levels and higher API levels than the rEF group. In the pEF group, the peak oxygen uptake (peak VO₂) and the anaerobic threshold was significantly higher than those in the rEF group. The peak VO₂ was significantly and negatively correlated with AVI and API in the pEF group (All, P < 0.05), but not in the rEF group. Multivariate linear regression analyses demonstrated that AVI was independently associated with peak VO₂ (β = -0.34, P < 0.05) in the pEF group. In conclusion, AVI may be a useful factor for assessing exercise tolerance, particularly in CVD patients with pEF.

Brachial-ankle pulse wave velocity is associated with the risk of osteoporosis: a cross-sectional evidence from a Chinese community-based cohort

BACKGROUND

Association of arterial stiffness and osteoporosis has been well documented in elderly population. However, it is not clear whether they co-progress from the early stages through common mechanisms. The object of this study was to evaluate possible associations between arterial stiffness and osteoporosis by measuring brachial-ankle pulse wave velocity (baPWV) and the Osteoporosis Self-Assessment Tool for Asia (OSTA) index among a healthy population of Chinese aged 40 years and older. Whether baPWV can be used as a predictor of osteoporosis on OSTA was further assessed.

METHODS

This study was cross-sectional in design. Of 3984 adults aged 40 years and older in the Yunyan district of Guiyang (Guizhou, China) who underwent both OSTA and baPWV measurements within 1 month, 1407 were deemed eligible for inclusion (women, 1088; men, 319).

RESULTS

The mean baPWV was 1475 ± 302 cm/s (range,766-3459 cm/s). baPWV in 110 individuals with high risk of osteoporosis (OSTA index < - 4) was higher than that of individuals with non-high risk (1733 ± 461 cm/s vs. 1447 ± 304 cm/s, P < 0.001). OSTA index was negatively correlated with baPWV(ρ = - 0.296, P < 0.001) after adjusting for age, sex, body mass index, waist circumference, diastolic blood pressure, and creatinine clearance rate. baPWV was an independent predictor for the presence of high risk of osteoporosis (β = - 0.001, P < 0.001) and was consistent across age and sex subgroups, and the optimal baPWV cutoff value for predicting the presence of high risk of osteoporosis and fracture was 1693 cm/s. The AUC was 0.722 (95% confidence interval [CI], 0.667-0.777; P < 0.001, sensitivity of 52.8% and specificity of 83.6%).

CONCLUSIONS

We conclude that arterial stiffness measured by baPWV is well correlated with the severity of osteoporosis evaluated by OSTA. baPWV index may be a valuable tool for identifying individuals with risk of developing osteoporosis.

Noninvasive Measurement of Time-Varying Arterial Wall Elastance Using a Single-Frequency Vibration Approach

The arterial wall elastance is an important indicator of arterial stiffness and a kind of manifestation associated with vessel-related disease. The time-varying arterial wall elastances can be measured using a multiple-frequency vibration approach according to the Voigt and Maxwell model. However, such a method needs extensive calculation time and its operating steps are very complex. Thus, the aim of this study is to propose a simple and easy method for assessing the time-varying arterial wall elastances with the single-frequency vibration approach. This method was developed according to the simplified Voigt and Maxwell model. Thus, the arterial wall elastance measured using this method was compared with the elastance measured using the multiple-frequency vibration approach. In the single-frequency vibration approach, a moving probe of a vibrator was induced with a radial displacement of 0.15 mm and a 40 Hz frequency. The tip of the probe directly contacted the wall of a superficial radial artery, resulting in the arterial wall moving 0.15 mm radially. A force sensor attached to the probe was used to detect the reactive force exerted by the radial arterial wall. According to Voigt and Maxwell model, the wall elastance (E_single) was calculated from the ratio of the measured reactive force to the peak deflection of the displacement. The wall elastances (E_multiple) measured by the multiple-frequency vibration approach were used as the reference to validate the performance of the single-frequency approach. Twenty-eight healthy subjects were recruited in the study. Individual wall elastances of the radial artery were determined with the multiple-frequency and the single-frequency approaches at room temperature (25 °C), after 5 min of cold stress (4 °C), and after 5 min of hot stress (42 °C). We found that the time-varying E_single curves were very close to the time-varying E_multiple curves. Meanwhile, there was a regression line (E_single = 0.019 + 0.91 E_multiple, standard error of the estimate (SEE) = 0.0295, p < 0.0001) with a high correlation coefficient (0.995) between E_single and E_multiple. Furthermore, from the Bland-Altman plot, good precision and agreement between the two approaches were demonstrated. In summary, the proposed approach with a single-frequency vibrator and a force sensor showed its feasibility for measuring time-varying wall elastances.

Roles of arterial pressure volume index and arterial velocity pulse index trajectories in risk prediction in hypertensive patients with heart failure with preserved ejection fraction

Background: Arterial pressure volume index (API) and arterial velocity pulse index (AVI) contribute to the development of vascular damage and cardiovascular disease. However, the relationship between common API/AVI trajectories and cardiovascular outcomes in hypertensive patients with heart failure with preserved ejection fraction (HFpEF) is unknown.Methods: A total of 488 consecutive hypertensive patients with HFpEF who repeatedly underwent API/AVI measurements were prospectively examined. We then applied API/AVI measurements into actual clinical practice. Latent mixture modeling was performed to identify API/AVI trajectories. Hazards ratios (HRs) were measured using Cox proportional hazard models.Results: We identified four distinct API/AVI trajectory patterns: low (7.6%), moderate (43.8%), high (28.9%), and very high (19.7%). Compared with the low group, higher API trajectories were associated with increased risk of total cardiovascular events (high group, adjusted HR: 2.91, 95% confidence interval [CI]: 1.97-4.26; very high group, adjusted HR: 2.46, 95%CI: 1.18-3.79). Consistently, higher AVI trajectories were also associated with a higher risk of total cardiovascular events (high group, adjusted HR: 2.58, 95%CI: 1.23-5.47; very high group, adjusted HR: 3.12, 95%CI: 1.83-6.08), compared with the low trajectory group.Conclusion: High API/AVI trajectories are strong predictors of cardiovascular risk in hypertensive patients with HFpEF. Among these patients, measuring API/AVI may improve risk stratification and provide additional information to tailor treatment strategies.

Assessment of vascular stiffness using different modalities in patients with systemic lupus erythematosus: a case control study

Background

Cardiovascular disease is a major cause of morbidity and mortality in systemic lupus erythematosus (SLE) patients. Accurate risk stratification would require a simple, non-invasive index integrating all traditional and emerging risk factors. Vascular stiffness fulfills these requirements and has better predictive value for cardiovascular events than traditional risk factors in hypertensives and patients with coronary artery disease. Our aim was to determine whether arterial stiffness is increased in SLE patients compared to healthy controls and to correlate the arterial stiffness in SLE patients with cardiovascular risk factors, namely, hypertension and diabetes mellitus.

Results

This study included 50 SLE patients and 50 age- and gender-matched healthy individuals. SLE patients had higher median aortic stiffness index (SI) and lower strain and distensibility, compared to controls (p value for all < 0.001). SLE patients had significantly impaired flow-mediated dilation (FMD) compared to controls: the median (range) in SLE patients was 8.82 (2.5–21.87), compared to 19 (12–37.5) in controls (z = − 7.695, p ˂ 0.001). Regarding quality arterial stiffness (QAS) parameters, SLE patients had significantly lower median carotid distension, distensibility coefficient, and compliance coefficient, with higher median carotid SI, carotid pulse wave velocity (PWV), and augmentation index (AI), compared to controls (p value for all ≤ 0.001). SLE patients had a higher median cf-PWV 6.5 m/s (4.8–11.8), compared to a median of 4.6 m/s (3.8–6.9) in controls (z = − 8.193, p ˂ 0.001). Linear regression analysis to adjust for hypertension and diabetes mellitus yielded a statistically significant difference between both groups for all of the above parameters (p = 0.014 for maximum carotid intima media thickness (IMT) and < 0.001 for remaining parameters), with the exception of the maximum carotid augmentation index (p = 0.184).

Conclusion

SLE patients have significantly increased arterial stiffness and impaired FMD compared to healthy controls. This is true even after adjusting for hypertension and diabetes mellitus, highlighting the fact that SLE could be an independent cardiovascular risk factor. These findings emphasize the need for early management of SLE together with aggressive risk factor modification.

Effects of different intensities and durations of aerobic exercise training on arterial stiffness

[Purpose] In the present study, we investigated the effects of regular aerobic training with different intensities and durations on new indices of arterial stiffness measured via an upper-arm oscillometric device. [Participants and Methods] We gathered data from 41 middle-aged and older people (age 65.0 ± 11.7 years). Participants were randomly divided into five groups: (1) 15 minutes of low intensity aerobic training (n=10); (2) 30 minutes of low intensity training (n=7); (3) 15 minutes of moderate-intensity training (n=9); (4) 30 minutes of moderate-intensity training (n=8); and (5) a non-training group (n=7). Training was conducted for 8 weeks, three times per week. Arterial pulse wave index, arterial pressure-volume index, brachial-ankle and heart-brachial pulse wave velocity, cardio-ankle vascular index, brachial and ankle blood pressure, heart rate, and peak oxygen uptake were measured before and after the intervention. [Results] All indicators of arterial stiffness and brachial and ankle blood pressure in the exercise groups were significantly lower after versus before the intervention. Peak oxygen uptake did not differ before versus after the intervention. [Conclusion] The present findings indicate that regular aerobic exercise may be important in reducing arterial stiffness regardless of the intensity or duration of aerobic exercise.

NOVEL METHOD FOR ASSESSING ARTERIAL STIFFNESS BASED ON OSCILLOMETRIC BLOOD PRESSURE MEASUREMENT

Arterial stiffness is a major contributor to cardiovascular diseases. The aim of this study is to explore the physiological significance of the brachial mechanical parameters, which could be estimated from oscillometric blood pressure (BP) measurement, and investigate on the potential of these arterial parameters as an index of arterial stiffness. The mechanical characteristics of brachial artery were modeled based on the collapsible tube theory, which includes two important parameters to describe the compliance of brachial artery. After the model validation, the arterial parameters were estimated from the measured oscillometric envelope of 56 subjects by solving an inverse problem. The physiological significance of these parameters was explored by analyzing their association with pulse wave velocity (PWV) as well as with the BP. Arterial compliance parameters were successfully estimated from the envelope of the oscillometric pulse wave in the BP measurement. The parameters were found to be linearly associated with age, PWV, and BP. These results suggest that our method may provide a potential approach to assess arterial compliance based on oscillometric measurement of BP.

Seasonal variation of novel arterial stiffness indexes in Japanese hypertensive patients

Background and Objective: Seasonal variation of blood pressure (BP) is well known, and a relationship between increases in BP and the incidence of cardiovascular accidents (CVAs) in the winter has been reported. Parameters of arterial stiffness may exhibit seasonal variation; however, available data are currently limited. Novel arterial stiffness indexes, namely the arterial velocity pulse index (AVI) and arterial pressure-volume index (API), can be determined through usual maneuver for BP measurement during the regular examination in the outpatient clinic.The present study assessed the seasonal variation of AVI and API in 59 hypertensive patients undergoing stable treatment and regularly visiting our outpatient clinic over a period of 30 months. Methods: BP, pulse rate (PR), AVI, and API were measured using the AVE-1500 (Pasesa) in the sitting position. Six time frames of assessment were established. All measurements (average: 17.9 measurements per person) were sorted using these six time frames, and their averages were used for analysis. Results: Significant seasonal variations in PR (P < 0.001) and AVI (P < 0.001), along with weak variation in systolic BP (SBP) (P = 0.047) and marginal variation in API (P = 0.055), were confirmed by repeated analysis of variance. SBP, API, and PR were decreased, whereas AVI was increased in the summer. Coefficient variations were SBP 5.1%, PR 4.9%, AVI 12.6%, and API 10.6%. Conclusion: AVI was associated with reflected wave like as augmentation index. Thus, a high AVI may suggest increased central wave reflection. Although the significance of seasonal variation of AVI remains unknown, AVI may influence seasonal variations in the incidence of CVA.

Increase in the Arterial Velocity Pulse Index of Patients with Peripheral Artery Disease

Background

Recently, a simple parameter calculated from the brachial pressure waveform recorded using an oscillometric device (arterial velocity pulse index [AVI]: ratio of the forward/reflected pressure wave amplitudes) has become available to assess the pathophysiological abnormalities associated with vascular damage. Peripheral artery disease (PAD) represents one of the disease entities associated with the advanced stages of atherosclerotic vascular damage. The present study was conducted to examine whether an increase in the AVI might be influenced by the presence of PAD.

Methods and Results

The AVI was measured from oscillometric recordings of the brachial pressure waveform, and the ankle-brachial pressure index (ABPI) was determined by an oscillometric method. Study 1: In 341 consecutive patients admitted for the management of cardiovascular disease and/or cardiovascular risk factors, the ABPI and the AVI were measured simultaneously. An ABPI ≤0.90 was observed in 19 subjects, and logistic regression analysis revealed a significant association between AVI and ABPI ≤0.90 (odds ratio = 1.81; 95% confidence interval = 1.15-2.84; p = 0.01). Study 2: In another 19 patients with PAD, percutaneous transluminal angioplasty resulted in a decrease in the AVI from 31 ± 8 to 27 ± 8 (p < 0.01).

Conclusion

Possible presence of PAD must be taken into account while applying the AVI for the assessment of vascular damage.

New non-invasive indexes of arterial stiffness are significantly correlated with severity and complexity of coronary atherosclerosis

BACKGROUND

Endothelial dysfunction and increased arterial stiffness gradually develop before the manifestation of catastrophic cardiovascular events. Therefore, detection and assessment of vascular function are required to address pre-existing pathological conditions. However, the currently available diagnostic devices and methods are insufficient due to variability among investigators and the time-consuming nature of manual procedures.

METHODS

Recently, novel devices were developed for the detection of both arterial stiffness and endothelial dysfunction in a single blood pressure measurement using a cuff-oscillometric technique (AVE-1500, Shisei Datum, Japan). API (arterial pressure volume index) is defined as the reciprocal of the slope of the tangent of the brachial artery pressure-volume curve, and AVI (arterial velocity pulse index) is defined as the ratio of the difference between the ejection and reflection waves. In the present study, we performed retrospective, cross-sectional analyses of subjects (n = 102; mean age = 70.5 ± 10.4 years) with detailed coronary angiographic examinations and clinical background parameters.

RESULTS

After adjusting for various variables using multiple linear regression analyses, we found that API, but not AVI, was significantly correlated with coronary artery severity and complexity scores.

CONCLUSIONS

We propose that API may be a new vascular index useful for monitoring and assessing the severity and complexity of atherosclerosis in subjects with coronary artery disease and for evaluating atherosclerotic diseases.

New indices of arterial stiffness measured with an upper-arm oscillometric device in active versus inactive women

Arterial velocity pulse index (AVI) and arterial pressure-volume index (API), new indicators of arterial stiffness, are risk factors for the development of cardiovascular disease. Regular aerobic exercise decreases arterial stiffness. In fact, pulse wave velocity (PWV), index of arterial stiffness, is lower in endurance-trained than in untrained young adults. However, the effect of regular aerobic exercise on AVI and API remains unknown. This study investigates the effect of regular aerobic exercise on AVI and API, new indicators of arterial stiffness. We gathered data from 18 recreationally active females (active group, age: 18 ± 1 years, 2 ± 2 h/week, 3 ± 2 times/week, ≥2 years of aerobic endurance training) and 18 recreationally inactive females (inactive group, age: 18 ± 1 years, ≥2 years without such training) in a cross-sectional study. Height, body weight, body mass index, AVI, API, brachial blood pressure, heart rate, and 20-m multistage shuttle run test were measured in a quiet room at a temperature between 24°C and 25°C. AVI and API were lower in the active group than in the inactive group (P < 0.01). Number of 20-m shuttles was negatively correlated with AVI (P < 0.01, r = -0.8) and API (P < 0.01, r = -0.8). These results suggest that regular aerobic exercise training decreases AVI and API in young females.

Screening Validity of Arterial Pressure-Volume Index and Arterial Velocity-Pulse Index for Preclinical Atherosclerosis in Japanese Community-Dwelling Adults: the Nagasaki Islands Study

AIM

The arterial pressure-volume index (API) and arterial velocity-pulse index (AVI) are novel measurement indices of arterial stiffness. This study was performed to examine the screening validity of the API and AVI for preclinical atherosclerosis in Japanese community-dwelling adults.

METHODS

We conducted a cross-sectional study of 2,809 participants aged ≥40 years who underwent Japanese national medical check-ups from 2014 to 2016. Preclinical atherosclerosis was defined as a mean carotid intima-media thickness (CIMT) of ≥1.0 mm. Multivariable linear regression analysis was performed to investigate the association of CIMT with API and AVI, adjusting for body mass index, sex, and the Framingham-D'Agostino score. We also examined receiver operating characteristic curves, sensitivity, and specificity to predict preclinical atherosclerosis defined by the CIMT. The cardio-ankle vascular index was also measured for comparison with the API and AVI.

RESULTS

Of 2,809 participants, 68 (2.4%) had preclinical atherosclerosis. In the multivariable linear regression analysis, the API and AVI maintained a positive association with the mean CIMT (B=2.6, P=0.009 and B=3.7, P=0.001, respectively). The cut-offs of the API and AVI that demonstrated better sensitivity and specificity for detection of subclinical atherosclerosis were 31 [area under the curve (AUC), 0.64] and 29 (AUC, 0.60).

CONCLUSIONS

The API and AVI were positively associated with preclinical carotid atherosclerosis independent of the participants' cardiovascular risk. The ability of these scores to predict carotid atherosclerosis could make them a useful screening tool for atherosclerosis.

Cardiac rehabilitation in patients with cardiovascular disease leads various hemodynamic parameters obtained using simple non-invasive tests to their appropriate levels

We evaluated whether comprehensive cardiac rehabilitation (CR) in patients with cardiovascular disease (CVD) could improve various hemodynamic parameters obtained using simple non-invasive tests. We analyzed 48 CVD patients with (n = 38, CR group) or without (n = 10, non-CR group) a CR program, and prospectively followed them for 12 months. Various parameters were measured at baseline and after 12 months using 3 simple non-invasive tests: blood pressure (BP) and severity of atherosclerosis [arterial velocity pulse index (AVI) and atrial pressure volume index] were determined using PASESA®, an index of total autonomic nerve activity and a coefficient of variation of the R-R interval (CVRR) were determined using eHEART®, and the total peripheral resistance, stroke volume and cardiac index (CI) were determined using nico®. The main hemodynamic parameters did not change between baseline and 12 months in both groups. Patients in the CR group were divided into higher (H-) and lower (L-) systolic BP (SBP) or AVI according to the average value of SBP or AVI at baseline in the CR group. Patients with H-SBP or H-AVI in the CR group showed a significant reduction of SBP or AVI at 12 months. In addition, patients in the CR group were divided into H- and L- CI or CVRR according to the average value of CI or CVRR at baseline in the CR group. Patients with L-CI or L-CVRR in the CR group significantly improved after 12 months. In conclusion, CR may lead various hemodynamic parameters obtained using simple non-invasive tests to their appropriate levels.

Low-frequency and low-intensity ultrasound irradiation to the forearm improves an index of arterial stiffness in subjects with type 2 diabetes and hypertension

Objectives

The arterial pressure-volume index (API) is a non-invasive assessment of arterial stiffness, and is suggested as a useful predictor of future cardiovascular events. The aim of the present study was to determine the effects of low-frequency and low-intensity ultrasound applied to the forearm for 10 min on the API in Japanese subjects with type 2 diabetes and hypertension.

Methods

We examined the effects of low-frequency and low-intensity ultrasound (800 kHz, 25 mW/cm²) applied to the forearm for 10 min on the API, blood pressure (BP) and pulse rate in 40 Japanese subjects (13 men and 27 women; mean age ± SE, 70 ± 2 years) with type 2 diabetes and hypertension, who had the API > 30 and systolic BP > 140 mmHg at a clinic visit. We also examined the effects of the ultrasound irradiation for 10 min on the API, BP and pulse rate in 33 Japanese subjects (11 men and 22 women; mean age ± SE, 65 ± 2 years) with type 2 diabetes and hypertension, who had the API > 30 and systolic BP (SBP) < 140 mmHg.

Results

The API, systolic BP and pulse rate in the ultrasound treatment group was significantly lower than the baseline values in the subjects who had the API > 30 and either the baseline of systolic BP > 140 mmHg or systolic BP < 140 mmHg.

Conclusions

The low-frequency and low-intensity ultrasound irradiation to the forearm for 10 min might be useful as a preventive application for arterial stiffness in subjects with type 2 diabetes and hypertension.

Association between novel arterial stiffness indices and risk factors of cardiovascular disease

BACKGROUND

Prevention and early detection of arterial stiffness are required to avoid severe cardiovascular events. Recently, new noninvasive arterial stiffness indices, the arterial pressure volume index (API) and the arterial velocity pulse index (AVI), have been developed. The purpose of this study was to examine the clinical validity of these new indices by investigating the association between known risk factors of cardiovascular disease (CVD) and API or AVI in a large population.

METHODS

This cross-sectional survey included 7248 adults who underwent an annual medical checkup at a single medical institution. API and AVI were measured using cuff oscillometry by trained nurses. We used correlation coefficients, t-tests, and multiple regression analyses to evaluate associations, and calculated intraclass correlation coefficients (ICC) to examine test-retest reliabilities of these indices.

RESULTS

Mean age was 45.5 years (SD = 5.8), and 4083 (56.3 %) participants were men, while 3165 were women. Mean values of API and AVI were 25.1 (SD = 7.0) and 16.6 (SD = 5.4), respectively. API was strongly correlated with body mass index (BMI), systolic blood pressure (sBP), and diastolic blood pressure (dBP) (r > 0.3, p < 0.001). AVI was strongly correlated with age, sBP, and API (r > 0.3, p < 0.001). Multiple regression analyses showed that sex, age, BMI, and sBP were independently associated with API. Sex, age, BMI, sBP, fasting plasma glucose (FPG), and smoking condition were also independently associated with AVI. As reliabilities of measurements, the ICC of API was 0.74, and the ICC of AVI was 0.80.

CONCLUSIONS

These new noninvasive arterial stiffness indices, which had high test-retest reliabilities, were associated with known risk factors of CVD. Further study is warranted to determine the clinical validity of these indices.

Characteristic Ratio-Independent Arterial Stiffness-Based Blood Pressure Estimation

Noninvasive blood pressure (BP) measurement is an important tool for managing hypertension and cardiovascular disease. However, automated noninvasive BP measurement devices, which are usually based on the oscillometric method, do not always provide accurate estimation of BP. It has been found that change in arterial stiffness (AS) is an underlying mechanism of disagreement between an oscillometric BP monitor and a sphygmomanometer. This problem is addressed by incorporating parameters related to AS in the algorithm for BP measurement. Pulse transit time (PTT) is first used to estimate AS parameters, which are fixed into a model of the oscillometric envelope. This model can then be used to perform curve fitting to the measured signal using only four parameters: systolic BP, diastolic BP, mean BP, and lumen area at zero transmural pressure. The proposed technique is independent of the experimentally determined characteristic ratios that are commonly used in existing oscillometric methods. The accuracy of the proposed technique was evaluated by comparing with the same model without incorporation of AS, and with reference BP device measurements. The new method achieved standard deviation of error less than 8 mmHg and mean error less than 5 mmHg. The results show consistency with ANSI/AAMI SP-10 standard for noninvasive BP measurement techniques.

Assessment of various parameters using simple non-invasive tests in patients with cardiovascular diseases with or without cardiac rehabilitation

Cardiac rehabilitation (CR) improves cardiac function and exercise capacity in patients with cardiovascular disease (CVD). Simpler techniques are needed for use by physicians in the examination room to assess the usefulness of CR. We enrolled 46 consecutive CVD patients in a CR program (CR group) and prospectively followed them for 3 months. We compared them to 18 age-, gender- and body mass index-matched CVD patients without CR (non-CR group). Various parameters were measured at baseline and after 3 months using 3 simple non-invasive tests: severity of atherosclerosis [arterial velocity pulse index and arterial pressure volume index (API)] were determined using PASESA®, an autonomic nerve total activity amount index and a coefficient of variation of the R–R interval (CVRR) were determined using eHEART®, and peripheral resistance index, pressure rate product, stroke volume and cardiac index were determined using nico®]. There were no significant differences in patient characteristics including percentages (%) of ischemic heart disease and heart failure between the non-CR and CR groups. Systolic blood pressure (SBP), diastolic BP, heart rate and API at baseline significantly decreased and CVRR at baseline significantly increased after 3 months in the CR group, but not in the non-CR group. In addition, ΔAPI (Δ = the value after 3 months minus the value at baseline) was positively associated with ΔSBP in the CR group. In conclusion, CR significantly decreased BP and improved atherosclerosis and sympathetic nerve activity. These findings suggest that simple non-invasive tests may be useful for assessing the effects of CR.

Association of Arterial Pressure Volume Index With the Presence of Significantly Stenosed Coronary Vessels

Background

A blood pressure (BP) monitoring system (PASESA^®) can be used to easily analyze the characteristics of central and peripheral arteries during the measurement of brachial BP.

Methods

We enrolled 108 consecutive patients (M/F = 86/22, age 70 ± 10 years) who underwent coronary angiography (CAG) due to suspected coronary artery disease (CAD) in whom we could measure various parameters using PASESA^® in addition to brachial-ankle pulse wave velocity (baPWV). The patients were divided into two groups: patients who did not have significantly stenosed coronary vessel disease (n = 33, non-SVD group) and those who had at least one significantly stenosed coronary vessel (n = 75, SVD group). The characteristics of central and peripheral arteries (arterial velocity pulse index (AVI) and arterial pressure volume index (API), respectively) and baPWV were measured. Estimated central BP (eCBP) was calculated from the data obtained from PASESA^®, and CBP was also measured simultaneously by invasive catheterization.

Results

API, but not AVI and baPWV, in the SVD group was significantly higher than that in the non-SVD group. Although eCBP was significantly associated with CBP, there was no difference in eCBP between the groups. There were significant associations among API, AVI and baPWV, albeit these associations were relatively weak. A multivariate logistic regression revealed that API and β-blocker were significant independent variables that were associated with the presence of significant coronary stenosis. The cut-off level of API that gave the greatest sensitivity and specificity for the presence of SVD was 24 units (sensitivity 0.636 and specificity 0.667).

Conclusion

In conclusion, API, but not AVI or baPWV, is associated with the presence of significant coronary stenosis.

A vibration-based approach to quantifying the dynamic elastance of the superficial arterial wall

Background

The purpose of this study is to propose a novel method for assessing dynamic elastance of the superficial arterial wall using the sinusoidal minute vibration method.

Methods

A sinusoidal signal was used to drive a vibrator which induced a displacement of 0.15 mm with a frequency range between 40 and 85 Hz. The vibrator closely contacted with the wall of a superficial radial artery, and caused the arterial wall to shift simultaneously. A force sensor attached to the tip of the vibrator was used to pick up the reactive force exerted by the radial arterial wall. According to the Voigt and Maxwell models, a linear relationship was found between the maximum reactive force and the squared angular frequency of the vibration. The intercept of the linear function represents the arterial wall elastance. In order to validate the feasibility of our method, twenty-nine healthy subjects were recruited and the wall elastances of their radial arteries were measured at room temperature (25 °C), after a 5-min cold stress (4 °C) and a 5-min hot stress (42 °C), respectively.

Results

After the 5-min cold stimulation, the maximum radial wall elastance significantly increased from 0.441 ± 0.182 × 10⁶ dyne/cm to 0.611 ± 0.251 × 10⁶ dyne/cm (p = 0.001). In the 5-min hot stress, the maximum radial wall elastance significantly decreased to 0.363 ± 0.106 × 10⁶ dyne/cm (p = 0.013).

Conclusions

The sinusoidal minute vibration method proposed can be employed to obtain the quantitative elastance of a superficial artery under different thermal conditions, and to help assess the severity of arterial stiffness in conduit arteries.

Aerobic exercise training decreases plasma asymmetric dimethylarginine concentrations with increase in arterial compliance in postmenopausal women

BACKGROUND

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, increase with advancing age and menopausal status. ADMA plays a role in endothelial dysfunction and increasing arterial stiffness. Regular aerobic exercise has a positive effect on arterial function (i.e., arterial compliance). This study investigated the effects of aerobic exercise training on plasma ADMA concentrations and arterial compliance in postmenopausal women.

METHODS

Thirty postmenopausal women were divided into 2 groups: an exercise group (n = 20) and a control group (n = 10). Subjects in the exercise group completed 12 weeks of aerobic exercise training (65%-80% of maximal heart rate, 40-60 min/day, 3-6 days/week). Before and after each intervention, plasma ADMA concentrations and carotid arterial compliance were measured in all participants.

RESULTS

The baseline plasma ADMA concentrations, carotid arterial compliance, and most other key dependent variables did not differ between the 2 groups. In the exercise group, carotid arterial compliance significantly increased after exercise intervention (P < 0.01), and plasma ADMA concentrations significantly decreased (P < 0.05). In addition, changes in carotid arterial compliance after the exercise intervention were inversely correlated with changes in plasma ADMA concentrations (r = -0.367; P < 0.05).

CONCLUSIONS

We demonstrated that aerobic exercise training significantly decreased plasma ADMA concentrations with increase in carotid arterial compliance in postmenopausal women. These results suggest that reduction in ADMA may play an important role in the aerobic exercise training-induced increase in arterial compliance.