Pulse wave velocity in four extremities for assessing cardiovascular risk using a new device

Association between arterial stiffness and fat mass in patients with obesity

OBJECTIVE

The aim is to observe whether body composition in patients with high-risk obesity (body mass index >35 or between 30 and 34.9kg/m² with a waist circumference greater than 102cm in men or greater than 88cm in women) is related with vascular disease.

METHODS

This is a cross-sectional study of patients with high-risk obesity. Their fat mass was measured through bioimpedance and arterial stiffness through pulse wave velocity (PWV). Tertiles of patients were analyzed according to PWV distribution.

RESULTS

A total of 59 patients were analyzed. As PWV increased, BMI (p=0.02) and fat mass content (p<0.00) increased. There was also a significant increase in inflammation indicators.

CONCLUSIONS

In patients with high-risk obesity, there were differences in their body composition which were associated with changes in arterial stiffness and inflammatory burden.

Brachial-ankle pulse wave velocity with a custom device

BACKGROUND AND OBJECTIVES

The brachial-ankle pulse wave velocity (baPWV) is one of the most widely used arterial stiffness variables for assessing vascular risk. The abiPWV is a device that calculates various PWVs and the blood pressure ankle-brachial index (ABI). The device can also determine baPWV. The aim of this study was to calculate the baPWV with abiPWV, validate it with a reference device (VaSera) and study its clinical usefulness.

PATIENTS AND METHODS

We studied 113 patients (mean age, 53±12years), 59 (52%) of whom were women, and 10 (8.8%) of whom had a previous cardiovascular event. The participants were classified according to cardiovascular risk factors (CRFs) into groupI (none), groupII (1 or 2 CRFs) and groupIII (3 or more CRFs). The patients with a previous cardiovascular event were included in groupIII. All participants had their baPWV measured with abiPWV and VaSera.

RESULTS

The baPWV correlation between the 2 devices was r=0.93 (P<.001), and the percentage error calculated with the Bland-Altman analysis was 4.5%. The baPWV measured with abiPWV (in m/s) was as follows: groupI, 10.5±1.6; groupII, 13.8±2.9 (P<.001 when compared with groupI); and groupIII, 14.1±2.7 (P<.001 when compared with groupI). There were no differences between groupsII and III. The results with VaSera were comparable to those of abiPWV.

CONCLUSIONS

Measuring baPWV with the abiPWV is safe and has a similar clinical utility to that of VaSera. Incorporating this function into the options of abiPWV makes it a complete device for assessing arterial stiffness.

Brachial-ankle pulse wave velocity with a custom device

BACKGROUND AND OBJECTIVES

The brachial-ankle pulse wave velocity (baPWV) is one of the most widely used arterial stiffness variables for assessing vascular risk. The abiPWV is a device that calculates various PWVs and the blood pressure ankle-brachial index (ABI). The device can also determine baPWV. The aim of this study was to calculate the baPWV with abiPWV, validate it with a reference device (VaSera) and study its clinical usefulness.

PATIENTS AND METHODS

We studied 113 patients (mean age, 53 ± 12 years), 59 (52%) of whom were women, and 10 (8.8%) of whom had a previous cardiovascular event. The participants were classified according to cardiovascular risk factors (CRFs) into group I (none), group II (1 or 2 CRFs) and group III (3 or more CRFs). The patients with a previous cardiovascular event were included in group III. All participants had their baPWV measured with abiPWV and VaSera.

RESULTS

The baPWV correlation between the 2 devices was r = 0.93 (p < .001), and the percentage error calculated with the Bland-Altman analysis was 4.5%. The baPWV measured with abiPWV (in m/s) was as follows: group I, 10.5 ± 1.6; group II, 13.8 ± 2.9 (p < .001 when compared with group I); and group III, 14.1 ± 2.7 (p < .001 when compared with group I). There were no differences between groups II and III. The results with VaSera were comparable to those of abiPWV.

CONCLUSIONS

Measuring baPWV with the abiPWV is safe and has a similar clinical utility to that of VaSera. Incorporating this function into the options of abiPWV makes it a complete device for assessing arterial stiffness.

Cardio-ankle vascular index (CAVI) measured by a new device: protocol for a validation study

INTRODUCTION

Cardio-ankle vascular index (CAVI) is a new marker of arterial stiffness (AS) that can assess vascular wall stiffness in the aorta, femoral artery and tibial artery. CAVI is less affected by blood pressure at the time of measurement than the gold standard method (carotid-femoral pulse wave velocity (PWV)). Our group has developed a device called VOPITB (Velocidad Onda de Pulso Índice Tobillo Brazo) that uses the oscillometric method and easily and accurately measures the PWV in the arms and legs separately, allowing new AS indices to be studied. This article describes the research protocol to determine CAVI using VOPITB and to validate the device against a reference device (VaSera VS-1500) and assess its clinical utility.

METHODS AND ANALYSES

A cross-sectional, descriptive and observational study will be conducted. In all, 120 subjects (a minimum of 40% of subjects from any one gender) will be evaluated. CAVI will be determined from the measurement by VOPITB and VaSera VS-1500. For each subject, the average of the three readings taken with each device will be calculated. The Bland-Altman plot will be used to determine whether any bias exists in the data-that is, a tendency of the size of the difference to vary with the mean. The participants will be divided roughly equally between the following age bands: <30, 30-60 and >60 years.

ETHICS AND DISSEMINATION

The study has been approved by the ethics committee of the Hospital San Pedro de Alcántara, Cáceres, Spain. The participants will be required to sign an informed consent form before inclusion in the study, in accordance with the Declaration of Helsinki and WHO standards for observational studies. The dissemination plan of the research study results will be through presentations in relevant national and international conferences and scientific publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04303546.

Electrocardiogram-Based R Wave Pulse Wave Index for Assessment of Carotid Atherosclerosis

BACKGROUND Carotid atherosclerosis (CA) is a common disease in middle-aged and elderly people, which is closely related to cardiovascular and cerebrovascular disease. In this study, we investigated the benefits of the electrocardiogram (ECG)-based R wave pulse wave index (ERWVI) for the diagnosis of CA. MATERIAL AND METHODS According to CA examinations by color Doppler ultrasound, patients were assigned to positive and negative groups. The ECG R wave-Pulse wave transit time (ERWPTT) was obtained by synchronously collecting ECG signals (R wave in ECG) and the time variations in maximum finger pulse oxygen (DOP) on the ECG monitor. RESULTS ERPWI was positively correlated with sex, age, BMI, diastolic/systolic blood pressure, fasting blood glucose, uric acid, cholesterol and triglyceride levels, LDL-cholesterol, non-alcoholic fatty liver disease (NAFLD), creatinine, and homocysteine, and was negatively correlated with HDL-cholesterol (P<0.05). With the increase of ERPWI, the incidence of CA significantly increased to various degrees among the subgroups (P<0.05). The binary logistic regression model showed that ERPWI was an independent risk factor for atherosclerosis. The ROC curve showed that when ERPWI was above 0.505, the incidence of CA increased significantly. CONCLUSIONS There is a close relationship between ERPWI and CA. ERPWI is an independent risk factor for CA. ERPWI ≥0.505 can be used as a diagnostic threshold for CA and a reference index for the diagnosis of CA.

Measuring Blood Pulse Wave Velocity with Bioimpedance in Different Age Groups

In this project, we have studied the use of electrical impedance cardiography as a possible method for measuring blood pulse wave velocity, and hence be an aid in the assessment of the degree of arteriosclerosis. Using two different four-electrode setups, we measured the timing of the systolic pulse at two locations, the upper arm and the thorax, and found that the pulse wave velocity was in general higher in older volunteers and furthermore that it was also more heart rate dependent for older subjects. We attribute this to the fact that the degree of arteriosclerosis typically increases with age and that stiffening of the arterial wall will make the arteries less able to comply with increased heart rate (and corresponding blood pressure), without leading to increased pulse wave velocity. In view of these findings, we conclude that impedance cardiography seems to be well suited and practical for pulse wave velocity measurements and possibly for the assessment of the degree of arteriosclerosis. However, further studies are needed for comparison between this approach and reference methods for pulse wave velocity and assessment of arteriosclerosis before any firm conclusions can be drawn.

Regional assessment of carotid artery pulse wave velocity using compressed sensing accelerated high temporal resolution 2D CINE phase contrast cardiovascular magnetic resonance

BACKGROUND

Cardiovascular magnetic resonance (CMR) allows for non-invasive assessment of arterial stiffness by means of measuring pulse wave velocity (PWV). PWV can be calculated from the time shift between two time-resolved flow curves acquired at two locations within an arterial segment. These flow curves can be derived from two-dimensional CINE phase contrast CMR (2D CINE PC CMR). While CMR-derived PWV measurements have proven to be accurate for the aorta, this is more challenging for smaller arteries such as the carotids due to the need for both high spatial and temporal resolution. In this work, we present a novel method that combines retrospectively gated 2D CINE PC CMR, high temporal binning of data and compressed sensing (CS) reconstruction to accomplish a temporal resolution of 4 ms. This enables accurate flow measurements and assessment of PWV in regional carotid artery segments.

METHODS

Retrospectively gated 2D CINE PC CMR data acquired in the carotid artery was binned into cardiac frames of 4 ms length, resulting in an incoherently undersampled ky-t-space with a mean undersampling factor of 5. The images were reconstructed by a non-linear CS reconstruction using total variation over time as a sparsifying transform. PWV values were calculated from flow curves by using foot-to-foot and cross-correlation methods. Our method was validated against ultrasound measurements in a flow phantom setup representing the carotid artery. Additionally, PWV values of two groups of 23 young (30 ± 3 years, 12 [52%] women) and 10 elderly (62 ± 10 years, 5 [50%] women) healthy subjects were compared using the Wilcoxon rank-sum test.

RESULTS

Our proposed method produced very similar flow curves as those measured using ultrasound at 1 ms temporal resolution. Reliable PWV estimation proved possible for transit times down to 7.5 ms. Furthermore, significant differences in PWV values between healthy young and elderly subjects were found (4.7 ± 1.0 m/s and 7.9 ± 2.4 m/s, respectively; p < 0.001) in accordance with literature.

CONCLUSIONS

Retrospectively gated 2D CINE PC CMR with CS allows for high spatiotemporal resolution flow measurements and accurate regional carotid artery PWV calculations. We foresee this technique will be valuable in protocols investigating early development of carotid atherosclerosis.

Automatic or manual arterial path for the ankle-brachial differences pulse wave velocity

An automated method for measuring arterial path length with devices that determine pulse wave velocity (PWV) in peripheral arteries is frequently applied. We aimed to compare arterial path length measurements based on mathematical height-based formulas with those measured manually and to assess whether the ankle-brachial difference (abD-PWV) measured with the VOPITB device is comparable to that obtained by manual measurements. In 245 patients, a metric measuring tape was used to determine the arterial path length from the suprasternal notch to the midpoint of the VOPITB cuffs wrapped around the extremities, and the results were compared with those obtained with height-based formulas. We examined the relationship between the abD-PWV measured with both methods. The arterial path length measured manually was shorter than that calculated automatically by 5 ± 2 and 30 ± 4 cm—of 13% and 21% for the arms and legs, respectively (difference of 13% and 21%). As a result, the abD-PWV calculated with the automatic method was greater (automatic abD-PWV vs. manual: 462 ± 90 vs. 346 ± 79 cm/s). The Blant Altman plot showed a percentage error of: 15,2%, 7,5% and 17,3% for heart-brachial, heart-ankle length and abD-PWV respectively. In conclusion there were significant differences between manual and automated arterial length measurements and it translates into difference abD-PWV calculate from both methods. However, the Bland-Alman plot showed that abD-PWV was comparable for both techniques. The advantages of height-based formulas for the calculation of arterial path lengths suggest that they may be the recommended method for measuring the abD-PWV.

[Pulse wave velocity of the leg minus that of the arm measured with a custom device correlates to the coronary calcium quantification]

OBJECTIVE

The pulse wave velocity (PWV) in the great arteries is an indicator of vascular risk. Our objective was to identify the PWV index between the arms and legs that best correlates with the coronary calcium quantification (CCQ) and to compare it with other methods.

MATERIAL AND METHODS

Eight-one patients without vascular disease underwent the following measurements: CCQ; carotid intima-media thickness (IMT); carotid-femoral PWV (cfPWV), using COMPLIOR; and PWV in the arms and legs, with our own device (abiPWV, ankle brachial index PWV).

RESULTS

The difference in PWVs between the leg and arm (l-a PWV) measured with abiPWV was the index that best correlated with CCQ (r=0.401, P<.001). The correlation between IMT and CCQ and between CF-PWV and CCQ were r=0.366, P=.001; and r=0.385, P=.001, respectively. For a CCQ score higher than 100 as a marker of significant coronary arteriosclerosis, the areas under the curve for l-a PWV, IMT and cfPWV were 0.721 (P=.002), 0.758 (P<.001) and 0.636 (P=.058), respectively.

CONCLUSIONS

For patients without vascular disease, the l-a PWV measured with abiPWV appears to be the index that best correlates with the CCQ. This association is comparable to that between IMT and CCQ and between cfPWV and CCQ. The abiPWV is an easy-to-use device that can help improve vascular risk stratification.