Pulse Wave Velocity Variability Research Articles

Abstract 14: Arterial Stiffness in Obese Normotensive Children: The First Cardiovascular Risk Biomarker?

Introduction: Obesity is an emerging pandemic driven by consumption of a diet rich in fat, highly refined carbohydrates and a sedentary lifestyle in both children and adults. In obesity arterial stiffness (AS) often associated with endotelial dysfunction (ED) is an independent and strong predictor of cardiovascular disease (CVD) and is a precursor to atherosclerosis, systolic hypertension, cardiac diastolic dysfunction, and impairment of coronary and cerebral flow. In obese children, AS also promotes fatty liver disease whitch eventually leads to fibrosis. Aim of Study: In obese children (OC), central blood pressuere, arterial stiffness and endothelial dysfunction, liver steatosis/fibrosis were evaluated and compared with control group (CG), non-obese, non-hypertensive children. Methods: Carotid-femoral pulse wave velocity (PWV) is the current non-invasive method of choice to asses AS and PWV carotid-brachial variation pre- and post-induced transient ischemia of brachial artery to evaluate ED. Fibroscan (FS) and Control Attenuation Parameter (CAP) are a non-invasive reliable examination that allows to know the degree of liver steatosis and liver stiffness (fibrosis). Carotid-femoral PWV (AS) and PWV variation of brachial artery (ED) were assessed using Complior System® (Artech-Medical France). We evaluated 31 obese children between 10 and 13 years old (BMI 28.70±3.72) and compared to CG (between 11 and 13 years old, n=16, BMI 19.89±1.75) Results: In obese children (BMI 28.70±3.72 and Z score 2.02±0.42) vs CG (BMI 19.89±0.75 and Z core 0.57±0.24), PWV-CF (arterial stiffness) was significantly increased: 5.8±1.3 m/s vs. 3.4±0.9 m/s, p<0.01. PWV-CB variation were paradogical (endothelial dysfunction) after transient ischemia in obese children (△+9% compared to baseline) and it was as epected in the CG (△-12.2% compared to baseline) (P<0.001). Fibroscan and CAP revealed that the degree of steatosis was significantly higher in OC but no differences were found in the degree of liver fibrosis. Conclusions: We found a significatly increase in arterial stiffness in obese children compared to CG. Arterial stiffness in obese children often precedes the development of hypertension and liver fibrosis (even in the presence of liver steatosis) suggesting that arterial stiffness is one of the earliest biomarkers for increased cardiovascular risk. Interventions aimed at attenuating obesity in chidhood are emerging as important target to improve public health outcomes.

The influence of the digital pulse wave reference point on the pulse transit time measurement and variability

By measuring pulse wave velocity (PWV) via an arterial route, one can determine the stiffness of the artery. The duration between the ECG R-wave climax and a reference point on the digital pulse wave (DPW) in the same cardiac cycle must be determined in order to determine the pulse transit time (PTT). The time it takes for a pulse wave to travel from the heart to a peripheral artery location is known as the PTT. To find out the best reference point on the DPW that is associated with the least beat-beat coefficient of variation (CV) of PWV. The study was carried out on 10 healthy young males aged 19 years. A two-minute recording of the left middle fingertip DPW signals (through piezoelectric Finger Pulse Transducer) and lead II ECG (through three surface electrodes) were carried out. PTT was calculated as follows: from the climax of the electrocardiogram R wave to the onset (foot) of the DPW (PTT1); from the apex to the onset points of the DPW at 10% of its amplitude (PTT2); and from the apex to the onset points of the DPW at 50% of its amplitude (PTT3). PTT1, PTT, and PTT3 were measured on each volunteer and on the same cardiac cycles.

Cardiovascular variations in patients with major depressive disorder versus bipolar disorder

BackgroundDifferentiating depression in major depressive disorder and bipolar disorder is challenging in clinical practice. Therefore, reliable biomarkers are urgently needed to differentiate between these diseases. This study's main objective was to assess whether cardiac autonomic function can distinguish patients with unipolar depression (UD), bipolar depression (BD), and bipolar mania (BM). MethodsWe recruited 791 patients with mood disorders, including 191 with UD, 286 with BD, and 314 with BM, who had been drug free for at least 2 weeks. Cardiovascular status was measured using heart rate variability (HRV) and pulse wave velocity (PWV) indicators via finger photoplethysmography during a 5-min rest period. ResultsPatients with BD showed lower HRV but higher heart rates than those with UD and BM. The PWV indicators were lower in the UD group than in the bipolar disorder group. The covariates of age, sex, and body mass index affected the cardiovascular characteristics. After adjusting for covariates, the HRV and PWV variations among the three groups remained significant. Comparisons between the UD and BD groups showed that the variable with the largest effect size was the frequency-domain indices of HRV, very low and high frequency, followed by heart rate. The area under the receiver operating characteristic curve (AUC) for each cardiovascular variable ranged from 0.661 to 0.714. The High-frequency index reached the highest AUC.Limitations.Cross-sectional design and the magnitude of heterogeneity across participants with mood disorders limited our findings. ConclusionPatients with BD, but not BM, had a greater extent of cardiac imbalance than those with UD. Thus, HRV may serve as a psychophysiological biomarker for the differential diagnosis of UD and BD.

Global distributions of age- and sex-related arterial stiffness: systematic review and meta-analysis of 167 studies with 509,743 participants.

Arterial stiffening is central to the vascular ageing process and a powerful predictor and cause of diverse vascular pathologies and mortality. We investigated age and sex trajectories, regional differences, and global reference values of arterial stiffness as assessed by pulse wave velocity (PWV). Measurements of brachial-ankle or carotid-femoral PWV (baPWV or cfPWV) in generally healthy participants published in three electronic databases between database inception and August 24th, 2020 were included, either as individual participant-level or summary data received from collaborators (n=248,196) or by extraction from published reports (n=274,629). Quality was appraised using the Joanna Briggs Instrument. Variation in PWV was estimated using mixed-effects meta-regression and Generalized Additive Models for Location, Scale, and Shape. The search yielded 8920 studies, and 167 studies with 509,743 participants from 34 countries were included. PWV depended on age, sex, and country. Global age-standardised means were 12.5m/s (95% confidence interval: 12.1-12.8m/s) for baPWV and 7.45m/s (95% CI: 7.11-7.79m/s) for cfPWV. Males had higher global levels than females of 0.77m/s for baPWV (95% CI: 0.75-0.78m/s) and 0.35m/s for cfPWV (95% CI: 0.33-0.37m/s), but sex differences in baPWV diminished with advancing age. Compared to Europe, baPWV was substantially higher in the Asian region (+1.83m/s, P=0.0014), whereas cfPWV was higher in the African region (+0.41m/s, P<0.0001) and differed more by country (highest in Poland, Russia, Iceland, France, and China; lowest in Spain, Belgium, Canada, Finland, and Argentina). High vs. other country income was associated with lower baPWV (-0.55m/s, P=0.048) and cfPWV (-0.41m/s, P<0.0001). China and other Asian countries featured high PWV, which by known associations with central blood pressure and pulse pressure may partly explain higher Asian risk for intracerebral haemorrhage and small vessel stroke. Reference values provided may facilitate use of PWV as a marker of vascular ageing, for prediction of vascular risk and death, and for designing future therapeutic interventions. This study was supported by the excellence initiative VASCage funded by the Austrian Research Promotion Agency, by the National Science Foundation of China, and the Science and Technology Planning Project of Hunan Province. Detailed funding information is provided as part of the Acknowledgments after the main text.

Carotid arterial stiffness and cerebral blood flow variability in individuals with mild cognitive impairment

Background: It is unclear whether cerebral blood flow variability is a sign of impaired vascular function or an adaptation to chronic cerebral hypoperfusion in individuals with cognitive dysfunction. Elevated arterial stiffness increases transmission of pulsatile pressure to the brain, but the relationship between arterial stiffness, the magnitude of cerebral blood flow variability, and cognitive dysfunction is unknown. In this pilot study, we hypothesized that carotid artery stiffness would be higher in individuals with mild cognitive impairment (MCI) compared with individuals with normal cognition (NC), resulting in higher cerebral blood flow variability. Methods: In individuals with MCI (N=5) or NC (N=7), R-wave to common carotid artery (CCA) pulse wave velocity (PWV) was assessed as an index of arterial stiffness (via tonometry). CCA velocity (CCAv) and middle cerebral artery velocity (MCAv) were measured via transcranial Doppler ultrasound, with concurrent measurements of mean arterial pressure (MAP) via finger photoplethysmography. The amplitude of MAP, CCAv, and MCAv oscillations in the low frequency range (LF; 0.07-0.15 Hz) were assessed via fast Fourier transformation, and normalized to total power (0.04-0.4 Hz) for each participant to account for high inter-individual variability. Relationships between R-wave-carotid PWV and LF variability in CCAv and MCAv were assessed via correlational analyses. Results: There were no between-group differences for R-wave-carotid PWV (MCI: 0.91±0.16 m/s vs. NC: 0.87±0.07 m/s; P=0.70), mean CCAv (MCI: 31.8±8.8 cm/s vs. NC: 29.7±2.0 cm/s; P=0.54), mean MCAv (MCI: 50.9±6.5 cm/s vs. NC: 47.9±12.7 cm/s; P=0.63), or MAP (MCI: 102.1±10.2 mmHg vs. 104.7±13.8 mmHg; P=0.73). While there was also no difference between groups for nLF power of CCAv (MCI: 0.28±0.03 au vs. NC: 0.33±0.10 au; P=0.41), nLF power for MCAv was lower in the MCI group (MCI: 0.26±0.07 au vs. 0.43±0.12; P=0.02). Overall, there was a strong positive correlation between R-wave-carotid PWV and CCAv nLF power (R=0.81, P=0.005), but a weaker relationship for MCAv nLF power (R=0.56, P=0.09). While sub-group correlational analyses are limited based on the small sample sizes, relationships between R-wave-carotid PWV and CCAv nLF power were high for both MCI (R=0.98, P=0.02) and NC (R=0.79, P=0.06) groups, but were lower for MCAv nLF power (MCI: R=-0.12, P=0.88; NC: R=0.69, P=0.13). Conclusion: Contrary to our hypothesis, there were no differences in R-wave-carotid PWV between groups, and blood flow variability was either similar between groups (for CCAv), or lower in the MCI group (for MCAv). Overall, there was a strong positive relationship between R-wave-carotid PWV and blood flow variability in the CCA, which was also observed in sub-analysis of the MCI and NC groups. Future investigations with a larger sample size are needed to definitively determine the role of arterial stiffness on cerebral blood flow variability with cognitive dysfunction. R56AG068630, NIH National Institute for Aging (NIA), “Hemodynamic Mechanisms Linking Aortic Arch Stiffness with Brain Insult in Older Adults” This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The effects of experimental, meteorological, and physiological factors on short-term repeated pulse wave velocity measurements, and measurement difficulties: A randomized crossover study with two devices.

Large longitudinal studies with repeated pulse wave velocity (PWV) measurements, a direct measure of arterial stiffness, are required to realize the full potential of arterial stiffness in clinical practice. To facilitate such studies it is important to increase the power of a study by reducing within-subject variability of PWV, and to ease the use of a PWV device in clinical settings by minimizing PWV measurement difficulties. We systematically investigated experimental setting and meteorological conditions, as well as physiological factors and participant characteristics, to determine whether and to what extent they affected: between- and within-subjects variability of PWV recordings, and measurement difficulties of a particular device. We conducted a 2-week longitudinal block-randomized cross-over study with two blinded observers and two commonly used devices: applanation tonometry SphygmoCor CvMS and oscillometric Arteriograph to assess carotid-femoral (cfPWV) or aortic (PWVao) PWV, respectively. Our sample had uniform and wide-spread distribution of age, blood pressures, hypertensive status and BMI. Each participant (N = 35) was recorded 12 times over 3 visiting days, 7 days apart. On each day, recordings were made twice in the morning (7-10 a.m.) and afternoon (16-18 p.m.). Data were analyzed using multilevel mixed-effects models, separately for each device. In addition to age and mean arterial pressure (MAP) that strongly affected both cfPWV and PWVao, other significant factors appeared to indicate a measurement approach. cfPWV as a more direct measure of arterial stiffness was additionally affected by hypertension status, outdoor temperature, interaction of MAP with outdoor temperature and the order of visit, with MAP within-subject variability contributing on average 0.27 m/s to difference in repeated measurements at 5°C and 0.004 m/s at 25°C. PWVao measurements derived at a single brachial site were more dependent on age than cfPWV and also depended on personal characteristics such as height and sex, and heart rate; with within-subject MAP variability adding on average 0.23 m/s to the difference in repeated measures. We also found that female sex significantly increased, and recording in afternoon vs. morning significantly decreased measurement difficulties of both devices. We identified factors affecting PWV recordings and measurement-difficulties and propose how to improve PWV measuring protocols.

Arterial stiffness and its influence on cerebral morphology and cognitive function.

Recently, arterial stiffness has been associated with cerebral small vessel disease (SVD), brain atrophy and vascular dementia. Arterial stiffness is assessed via pulse wave velocity (PWV) measurement and is strongly dependent on arterial blood pressure. While circadian blood pressure fluctuations are important determinants of end-organ damage, the role of 24-h PWV variability is yet unclear. We here investigated the association between PWV and its circadian changes on brain morphology and cognitive function in community-dwelling individuals. Single-centre, prospective, community-based follow-up study. The study cohort comprised elderly community-based participants of the Austrian Stroke Prevention Family Study which was started in 2006. Patients with any history of cerebrovascular disease or dementia were excluded. The study consists of 84 participants who underwent ambulatory 24-h PWV measurement. White matter hyperintensity volume and brain volume were evaluated by 3-Tesla magnetic resonance imaging (MRI). A subgroup of patients was evaluated for cognitive function using an extensive neuropsychological test battery. PWV was significantly related to reduced total brain volume (p = 0.013), which was independent of blood pressure and blood pressure variability. We found no association between PWV with markers of cerebral SVD or impaired cognitive functioning. Only night-time PWV values were associated with global brain atrophy (p = 0.005). This study shows a relationship of arterial stiffness and reduced total brain volume. Elevations in PWV during night-time are of greater importance than day-time measures.

Abstract 081: Pulse Wave Velocity And Blood Pressure Variability As Prognostic Indicators In Very Elderly Patients With Advanced Chronic Conditions

The prognostic value of BP elevation in very old patients with other chronic comorbidities is uncertain. We aimed to assess the prognostic impact of 24-hour BP (both brachial and central), BP variability, and pulse wave velocity (PWV) in very elderly patients hospitalized due to a chronic disease decompensation. We included 249 patients older than 80 years, admitted to the hospital due to decompensation of congestive heart failure (149), chronic obstructive pulmonary disease (60), chronic kidney disease with acute kidney injury (26), or other decompensated chronic conditions (14). During hospital stay, 24-h BP monitoring was performed (Mobil-O-Graph PWV). Mean values of brachial and central BP, aortic PWV, and BP variability (24-hour SD) were obtained in all participants. After discharge, patients were followed-up for one year. The primary outcome was total mortality. Hazard ratio (HR) of BP estimates (for 1 SD increase) were obtained through Cox models, adjusted for clinical confounders. During follow-up 72 patients (29%) died. Progression of heart failure (58%) was the most frequent cause of death. No differences were observed in 24-h BP between those who died or remained alive. Systolic BP-SD, and PWV were higher in patients who subsequently died, while 24-hour HR- SD was lower (Table). In fully adjusted models, PWV (HR: 3.54; 95%CI: 2.37-5.28), SD of 24-h brachial systolic BP (1.29; 1.00-1.67) and SD of 24-h heart rate (0.65; 0.46-0.91) were associated with the risk of mortality. We conclude that PWV, SBP and heart rate variabilities, but not the level of BP are associated with mortality in very old patients with advanced chronic conditions

ASSESSMENT OF STIFFNESS OF LARGE TO SMALL ARTERIES IN MULTI-STAGE RENAL DISEASE: A NUMERICAL STUDY

Objective: Arterial stiffness, as assessed via pulse wave velocity (PWV), is a major biomarker for risk assessment in patients with chronic kidney disease. However, the mechanisms responsible for the changes in PWV in the presence of kidney disease are not yet fully elucidated. In the present study, we aimed to investigate the direct effects attributable to biomechanical alterations to the arterial tree caused by renal disease progression on arterial stiffness, independent of any biochemical or compensatory effects. Design and method: Particularly, we used a previously validated one-dimensional (1-D) model of the cardiovascular system to simulate arterial pressure and flow at control with two kidneys (2KDN) and in arterial tree configurations representative of different stages of kidney disease, namely subject with a single functional kidney (1KDN), without any functional kidney (0KDN) and a transplant recipient (TX) with a single functional kidney re-attached to the external iliac artery. We evaluated the respective variations in blood pressure (BP), as well as arterial stiffness of large, medium, and small-sized vessels via carotid-femoral PWV (cfPWV), carotid-radial PWV (crPWV), and radial-digital PWV (rdPWV), respectively. Results: Our results showed that BP was increased in 1KDN and 0KDN, and that systolic BP values were restored in the TX configuration. Furthermore, a rise was reported in all PWVs for all tested configurations. The relative difference in stiffness from control to 0KDN was higher in the case of crPWV (+20 %); approximately twice the difference observed for cfPWV and rdPWV (+11 %). In TX, we observed a restoration of the PWVs to values close to 1KDN. Globally, it was demonstrated that alterations of the outflow boundaries to the renal arteries as occurring in different stages of renal disease lead to changes in blood pressure and central and peripheral PWV in line with previously reported clinical data. Conclusions: Our findings suggest that the PWV variations observed in clinical practice with renal disease progression may be partially attributed to biomechanical alterations of the arterial tree, and their effect on blood pressure.

Assessment of Stiffness of Large to Small Arteries in Multistage Renal Disease Model: A Numerical Study

Arterial stiffness (AS), as assessed via pulse wave velocity (PWV), is a major biomarker for cardiovascular risk assessment in patients with chronic kidney disease (CKD). However, the mechanisms responsible for the changes in PWV in the presence of kidney disease are not yet fully elucidated. In the present study, we aimed to investigate the direct effects attributable to biomechanical changes in the arterial tree caused by staged renal removal, independent of any biochemical or compensatory effects. Particularly, we simulated arterial pressure and flow using a previously validated one-dimensional (1-D) model of the cardiovascular system with different kidney configurations: two kidneys (2KDN), one single kidney (1KDN), no kidneys (0KDN), and a transplanted kidney (TX) attached to the external iliac artery. We evaluated the respective variations in blood pressure (BP), as well as AS of large-, medium-, and small-sized arteries via carotid-femoral PWV (cfPWV), carotid-radial PWV (crPWV), and radial-digital PWV (rdPWV), respectively. Our results showed that BP was increased in 1KDN and 0KDN, and that systolic BP values were restored in the TX configuration. Furthermore, a rise was reported in all PWVs for all tested configurations. The relative difference in stiffness from 2KDN to 0KDN was higher in the case of crPWV (15%) in comparison with the increase observed for cfPWV (11%). In TX, we observed a restoration of the PWVs to values close to 1KDN. Globally, it was demonstrated that alterations of the outflow boundaries to the renal arteries with staged kidney removal led to changes in BP and central and peripheral PWV in line with previously reported clinical data. Our findings suggest that the PWV variations observed in clinical practice with different stages of kidney disease may be partially attributed to biomechanical alterations of the arterial tree and their effect on BP.

The Novel Bone Alkaline Phosphatase Isoform B1x Is Associated with Improved 5-Year Survival in Chronic Kidney Disease.

Circulating alkaline phosphatase (ALP) is an independent cardiovascular risk marker. Serum bone ALP (BALP) isoforms indicate bone turnover and comprise approximately 50% of total circulating ALP. In chronic kidney disease (CKD), mortality is highest in patients with increased ALP and BALP and low bone turnover. However, not all low bone turnover states are associated with increased mortality. Chronic inflammation and oxidative stress, features of protein energy wasting syndrome, induce cardiovascular BALP activity and fibro-calcification, while bone turnover is suppressed. Circulating BALP isoform B1x is associated with low ALP and low bone turnover and has been exclusively detected in CKD. We investigated the association of serum B1x with survival, abdominal aortic calcification (AAC) score, and aortic pulse wave velocity (PWV) in CKD. Serum ALP, BALP isoforms, parathyroid hormone (PTH), PWV, and AAC were measured repeatedly over 2 years in 68 prevalent dialysis patients. Mortality was assessed after 5 years. B1x was detected in 53 patients. A competing risk analysis revealed an association of B1x with improved 5-year survival; whereas, baseline PWV, but not AAC score, predicted mortality. However, PWV improved in 26 patients (53%), and B1x was associated with variation of PWV over time (p = 0.03). Patients with B1x had lower PTH and total ALP, suggesting an association with lower bone turnover. In conclusion, B1x is associated with time-varying PWV, lower circulating ALP, and improved survival in CKD, and thus may be an indicator of a reduced cardiovascular risk profile among patients with low bone turnover.

Decreased heritability and emergence of novel genetic effects on pulse wave velocity from youth to young adulthood

Increased arterial stiffness measured by pulse wave velocity (PWV) is an important parameter in the assessment of cardiovascular risk. Our previous longitudinal study has demonstrated that carotid-distal PWV showed reasonable stability throughout youth and young adulthood. This stability might be driven by genetic factors that are expressed consistently over time. We aimed to illustrate the relative contributions of genetic and environmental factors to the stability of carotid-distal PWV from youth to young adulthood. We also examined potential ethnic differences. For this purpose, carotid-distal PWV was measured twice in 497 European American (EA) and African American (AA) twins, with an average interval time of 3 years. Twin modelling on PWV showed that heritability decreased over time (62–35%), with the nonshared environmental influences becoming larger. There was no correlation between the nonshared environmental factors on PWV measured at visit 1 and visit 2, with the phenotypic tracking correlation (r = 0.32) completely explained by shared genetic factors over time. Novel genetic influences were identified accounting for a significant part of the variance (19%) at the second measurement occasion. There was no evidence for ethnic differences. In summary, novel genetic effects appear during development into young adulthood and account for a considerable part of the variation in PWV. Environmental influences become larger with age for PWV.

Normal and reference values for cardiovascular magnetic resonance-based pulse wave velocity in the middle-aged general population

BackgroundAortic stiffness, assessed through pulse wave velocity (PWV), is an independent predictor for cardiovascular disease risk. However, the scarce availability of normal and reference values for cardiovascular magnetic resonance imaging (CMR) based PWV is limiting clinical implementation. The aim of this study was to determine normal and reference values for CMR assessed PWV in the general population.MethodsFrom the 2,484 participants of the Netherlands Epidemiology of Obesity (NEO) study that have available CMR-PWV data, 1,394 participants free from cardiovasculard disease, smokers or treatment for diabetes, hypertension or dyslipidaemia were selected (45–65 years, 51% female). Participants were divided into sex, age and blood pressure (BP) subgroups. Normal values were specified for participants with a BP < 130/80 mmHg and reference values for elevated BP subgroups (≥ 130/80 and < 140/90 mmHg; and ≥ 140/90 mmHg). Differences between groups were tested with independent samples t-test or ANOVA. Due to an oversampling of obese individuals in this study, PWV values are based on a weighted analysis making them representative of the general population.ResultsNormal mean PWV was 6.0 m/s [95% CI 5.8–6.1]. PWV increased with advancing age and BP categories (both p < 0.001). There was no difference between sex in normal PWV, however in the BP > 140/90 mmHg women had a higher PWV (p = 0.005). The interpercentile ranges were smaller for participants < 55 years old compared to participants ≥ 55 years, indicating an increasing variability of PWV with age. PWV upper limits were particularly elevated in participants ≥ 55 years old in the high blood pressure subgroups.ConclusionThis study provides normal and reference values for CMR-assessed PWV per sex, age and blood pressure category in the general population.

Variability of peripheral pulse wave velocity in patients with diabetes mellitus type 2 during orthostatic challenge.

Diabetes mellitus 2 (DM2) is the seventh cause of death worldwide. One of the reasons is late diagnosis of vascular damage. Pulse wave velocity (PWV) has become an independent marker of arterial stiffness and cardiovascular risk. Moreover, the previous studies have shown the importance of beat-to-beat PWV measurement due to its variability among the heart cycle. However, variability of PWV (PWVv) of the whole body hasn't been examined yet. We have studied a group of DM II and heathy volunteers, to investigate the beat-to-beat mean PWV (PWVm) and PWVv in the different body positions. PWV of left lower and upper extremities were measured in DM2 (7 m/8 f, age 68+/-10 years, BP 158/90+/-19/9 mm Hg) and healthy controls (5 m/6 f, age 23+/-2 years, BP 117/76+/-9/5 mm Hg). Volunteers were lying in the resting position and of head-up-tilt in 45° (HUT) for 6 min. PWVv was evaluated as a mean power spectrum in the frequency bands LF and HF (0.04-0.15 Hz, 0.15-0.5 Hz). Resting PWVm of upper extremity was higher in DM2. HUT increased lower extremity PWVm only in DM2. Extremities PWVm ratio was significantly lower in DM2 during HUT compared to controls. LF and HF PWVv had the same response to HUT. Resting PWVv was higher in DM2. Lower extremity PWVv increased during HUT in both groups. PWVm and PWVv in DM2 differed between extremities and were significantly influenced by postural changes due to hydrostatic pressure. Increased resting PWVm and PWVv in DM2 is a marker of increased arterial stiffness.

Normal and reference values for MRI-based pulse wave velocity in the middle-aged general population

Abstract Background Aortic stiffness, assessed through pulse wave velocity (PWV), is an independent predictor for cardiovascular (CV) risk. However, the scarce availability of normal and reference values for magnetic resonance imaging (MRI) based PWV is limiting clinical implementation. Purpose The aim of this study was to determine normal and reference values for MRI-PWV in the general population. Methods From the 2,484 participants of the NEO study that have available MRI-PWV data, we selected 1,639 participants that were free from CV disease or treatment for diabetes, hypertension or dyslipidaemia (age range 45–65 years, 51% male). Participants were categorized by sex, age and blood pressure (BP) subgroups. Normal values were specified for healthy (&amp;lt;130/80 mmHg) and elevated BP (≥130/80 and &amp;lt;140/90 mmHg) and reference values for high BP (≥140/90 mmHg) subgroups. Differences between groups were tested with either an independent samples t-test or ANOVA. Results Overall mean PWV was 6.5 m/s [95% CI 6.4–6.6]. PWV increased significantly with advancing age and BP categories (both p&amp;lt;0.001). There was no difference in PWV between men and women, however a stronger increasing trend for women above 55 years old was observed (figure). The 95% CI's were smaller for participants &amp;lt;55 years old as compared to participants &amp;gt;55, indicating an increasing variability of PWV with age. The elevated PWV upper limits for the higher blood pressure subgroups are particularly evident in participants above 55 years old. Conclusion This study provides normal and reference values for MRI-assessed PWV per sex, age and blood pressure category. PWV percentiles (10, 25, 50, 75 and 90th) Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): The NEO study is supported by the participating departments, the Division and the Board of Directors of the Leiden University Medical Centre, and by the Leiden University, Research Profile Area “Vascular and Regenerative Medicine”

Long-term variations of arterial stiffness in patients with obesity and obstructive sleep apnea treated with continuous positive airway pressure.

Obstructive sleep apnea (OSA) is associated with cardiovascular co-morbidities and mortality. Arterial stiffness is an independent predictor of cardiovascular risk and mortality, and is influenced by the presence of OSA and related comorbidities. There is a paucity of data regarding long-term evolution of arterial stiffness in CPAP-treated OSA patients. We aimed to prospectively study long term PWV variations and determinants of PWV deterioration. In a prospective obese OSA cohort, at time of diagnosis and after several years of follow-up we collected arterial stiffness measured by carotid-femoral pulse wave velocity (PWV), clinical and metabolic parameters, and CPAP adherence. Univariate and multivariate analyses were performed in order to determine contributing factors. Seventy two OSA patients (men: 52.8%, median age: 55.8 years and median BMI of 38.5 kg/m2) with a prevalence of hypertension: 58.3%, type 2 diabetes: 20.8%, hypercholesterolemia: 33.3%, current or past smoking: 59.7%, were evaluated after a median follow-up of 7.4 [5.8; 8.3] years. Over the period of follow-up, the median increase in PWV was 1.34 [0.10; 2.37] m/s. In multivariate analysis, the increase in PWV was associated with older age (10 extra years was associated with a 5.24 [1.35; 9.12] % increase in PWV) and hypertension (a significant increase in PWV of 8.24 [1.02; 15.57] %). No impact of CPAP adherence on PWV evolution was found. PWV progression in CPAP-treated OSA patients is mainly related to pre-existing cardio-metabolic comorbidities and not influenced by CPAP adherence. In this high cardiovascular risk population, it is crucial to associated weight management and exercise with CPAP treatment.

Demonstration of Pressure-Dependent Inter and Intra-Cycle Variations in Local Pulse Wave Velocity Using Excised Bovine Carotid Artery.

Pulse wave velocity (PWV) is a function of the artery's material property, and its incremental nature in elastic modulus led to the concept of incremental PWV. Recent advancements in technology paved the way for reliable measurement of the variation in PWV within a cardiac cycle. This change in PWV has shown its potential as a biomarker for advanced cardiovascular diagnostics, screening, and has recently started using as a vascular screening tool and medical device development. In this work, we have demonstrated the concept of inter and intra-cycle variations of PWV with pressure using an excised bovine carotid artery. Results demonstrated that local PWV measured at the foot of the waveform followed the same trend as of the pressure. As the pressure level was increased to 68% across the cycles, resulting PWV increased up to 81%. An exponential PWV-Pressure relationship was obtained, in agreement with the widely used models. The incremental nature of PWV was recorded in a reflection-free region of the pressure pulse wave. This was further demonstrated in continuous pulse cycles with varying pressure ranges, by comparing the PWV values at two fiduciary points selected in the upstroke of the pressure wave. On average, a 48.11% increase in PWV was observed for 31.04% increase in pressure between the selected fiducial points within a pulse cycle. The article concludes, highlighting the clinical significance of incremental PWV.Clinical Relevance- This experimental study supplements the evidence for the incremental nature of PWV within a cardiac cycle, which has the potential for being a biomarker for advanced cardiovascular screening and diagnostics.

Variability of MRI Aortic Stiffness Measurements in a Multicenter Clinical Trial Setting: Intraobserver, Interobserver, and Intracenter Variability of Pulse Wave Velocity and Aortic Strain Measurement.

To assess intraobserver, interobserver, and scan-rescan variability of MRI aortic stiffness measurements in a multicenter trial setting. This study was a retrospective analysis of prospectively collected data in a multicenter prospective clinical trial (clinicaltrials.gov ID NCT01870739). Forty-five adult patients (31 men; mean age, 58 years ± 12 [standard deviation]; 15 patients per center; three centers) with arterial hypertension underwent standardized 3-T baseline MRI assessments between June and September 2014. Aortic strain was calculated from maximum and minimum aortic area measurements repeated three times by three readers at three aortic levels on three retrospectively gated axial gradient-echo (GRE) data sets. Pulse wave velocity (PWV) was assessed three times by five readers as Δx/Δt: Δx was measured on a parasagittal GRE image of the aortic arch, and Δt was extracted from ascending and descending aortic velocity curves created on three axial phase-contrast acquisitions. Intraobserver, interobserver, and scan-rescan variability was calculated using percentage coefficient of variation (COV). Aortic strain variability was lowest at the level of the distal descending aorta (DDA) with median COVs of 1.6% for intraobserver variability, 4.0% for interobserver variability, and 10.3% for scan-rescan variability. It was highest at the ascending aorta (AA) with COVs of 3.6% for intraobserver variability, 10.7% for interobserver variability, and 19.8% for scan-rescan variability. Variability of PWV was low: 0.7% for intraobserver variability, 1.5% for interobserver variability, and 8.1% for scan-rescan variability. Low variability can be achieved for aortic strain and PWV measurements in a multicenter trial setting using standardized MRI protocols. Although COV was lower when measuring aortic strain at DDA compared with AA, variability was acceptable at both anatomic locations.Supplemental material is available for this article.© RSNA, 2020.

PULSE WAVE VELOCITY AND CIRCADIAN VARIABILITY IN WELL CONTROLLED HYPERTENSIVE PATIENTS

Objective: Pulse wave velocity (PWV) is the gold standard for measuring large artery stiffness. A PWV >10m/s is considered a conservative estimate of significant alterations of aortic function in middle-aged hypertensive patients. Although commonly used, there are only a few reports investigating the 24-hour variability in PWV measurements, the determination of which is important when using PWV as a clinical marker of target organ damage. The aim of this study was to investigate the variability in PWV measurements and factors that may influence PWV variability during 24 hours. Design and method: A prospective study was conducted in 55 well controlled hypertensive patients (mean age 65.8 ± 11.8 years) and 21 healthy control subjects (mean age 55.6 ± 18.9 years). In all subjects, complete blood chemistry (including SUA determination), echocardiographic examination, office and 24 h ambulatory blood pressure (BP) as well as 24 h ambulatory PWV and central (BP) measurement were performed Results: 24 hours systolic BP, central BP and PWV (p < 0.001) were significantly higher in hypertensive patients in confront to health subjects, but not diastolic BP (p = 0.140) levels. Specifically, the mean of PWV, SBP and cBP during 24 h was 9.7 (±0.3) vs 7.7 (± 0.3); 131.6 (±4.6) vs 122.8 (±5.9) and 137.7 (±4.3) vs 125.6 (± 4.2) for hypertensives and controls respectively. However, the mean of DBP during 24 h was 78.7 (±4.1) for patients and 79.4 (±5.6) for controls. Moreover, PWV of patients was significantly correlated with SBP, DBP (r = 0.411) and cBP (r = 0.717) levels (p < 0.001). Significant correlations were found between PWV of controls and SBP (r = 0.616), DBP (r = 0.499) and cBP (r = 0.579) levels (p < 0.001). PWV levels presented a small variability during the whole 24 hours (±0,3) suggesting that measurement and reproducibility of this marker are not influenced by a circadian rhythm. Conclusions: PWV assessment may be performed any time during 24 hours in an outpatient clinic. In our study, we didn’t find a circadian variability that may influence the reproducibility of PWV.

Do patients with rheumatoid arthritis have aorta stiffer than general population?

ObjectiveThe aim of this study was to compare the aortic stiffness in patients with rheumatoid arthritis (RA) with the aortic stiffness in general population (GP) and to evaluate the determinants of their stiffness.Patients and methodsThe study group consisted of 80 patients with RA and 71 matched GP. Pulse wave velocity (PWV) was assessed by Doppler ultrasonography. Biochemical analyses were conducted for serum using standard laboratory procedures.ResultsThe mean PWV values were 7.687±1.03 versus 7.253±0.97 m/s in the patients with RA and GP, respectively. The average coordination of PWV and RA duration (RAD) variations is present by equation of linear regression: y=7.1309+0.0971x. By multiple regression analysis, C-reactive protein, (βst=0.1096, P=0.0009), RAD (βst=0.0917, P=0.0018), high-density lipoprotein cholesterol (βst=‒1.0610, P=0.0271), and cholesterol (βst=0.8491, P=0.0350) were independently associated with PWV in the patients with RA. C-reactive protein (βst=0.1057, P=0.0016), triglycerides (βst=0.1730, P=0.0117), low-density lipoprotein cholesterol (βst=0.1467, P=0.0206), and cholesterol (βst=0.0305, P=0.0261) were independently associated with PWV in the GP.ConclusionArterial stiffness was more pronounced in the patients with RA than in the GP. The independent determinants of arterial stiffness in both groups include traditional risk factors. RAD is determinant in patients with RA only.