Diurnal variation of arterial stiffness in healthy individuals of different ages and patients with heart disease

Aortic stiffness increases during prolonged sitting independent of intermittent standing or prior exercise

INTRODUCTION

Adverse vascular responses can occur during prolonged sitting, including stiffening of the aortic artery which may contribute to cardiovascular disease. Few studies have investigated the impact of intermittent standing and/or prior exercise as strategies to attenuate these potentially deleterious vascular changes.

PURPOSE

To investigate central vascular health responses during prolonged sitting, with and without intermittent standing and/or prior exercise.

METHODS

Fifteen males aged 18 to 31 years were recruited. Subjects completed a control condition [Sitting Only (SO)], and three randomized strategy conditions [Sitting Plus Standing (SSt), Exercise Plus Sitting (ES), Exercise Plus Sitting Plus Standing (ESSt)]. For all conditions, measurements of carotid-femoral pulse wave velocity (cfPWV) were taken at pre- and post-intervention, and brachial and central blood pressure (BP) at pre-, 1-h, 2-h, and 3-h intervention.

RESULTS

cfPWV significantly increased from pre- to post-intervention for all conditions (all p ≤ 0.043), as did brachial mean arterial pressure (MAP) and diastolic BP, and central MAP and diastolic BP for the control condition (all p ≤ 0.022). Brachial and central systolic BP were significantly higher during SO compared to ESSt at 1 h, and compared to ES for central systolic BP (all p ≤ 0.036).

CONCLUSIONS

Strategies of intermittent standing and/or prior exercise may not prevent aortic stiffening during sitting but may attenuate BP elevations in the brachial and aortic arteries. Future research should investigate causal mechanistic links between sitting and aortic stiffening, and other attenuation strategies.

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

Background

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.

Methods

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.

Results

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.

Conclusion

We identified factors affecting PWV recordings and measurement-difficulties and propose how to improve PWV measuring protocols.

Circadian and sex differences in carotid-femoral pulse wave velocity in young individuals and elderly with and without type 2 diabetes

The incidence of cardiovascular events is higher in the morning than in the evening and differs between sexes. We tested the hypothesis that aortic stiffness, a compelling cardiovascular risk factor, increases in the morning than in the evening in young, healthy individuals between 18 and 30 years (H18–30) or in older individuals between 50 and 80 years, either healthy (H50–80) or with type 2 diabetes (T2DM50–80). Sex differences were also investigated. Carotid-femoral pulse wave velocity (cf-PWV) recorded via Doppler Ultrasound, blood pressure and heart rate were checked at 6 a.m. and 9 p.m., at rest and during acute sympathetic activation triggered by handgrip exercise. Cf-PWV values were lower in the morning compared to the evening in all groups (p < 0.01) at rest and lower (p = 0.008) in H18–30 but similar (p > 0.267) in the older groups during sympathetic activation. At rest, cf-PWV values were lower in young women compared to young men (p = 0.001); however, this trend was reversed in the older groups (p < 0.04). During sympathetic activation, the cf-PWV was lower in women in H18–30 (p = 0.001), similar between sexes in H50–80 (p = 0.122), and higher in women in T2DM50–80 (p = 0.004). These data do not support the hypothesis that aortic stiffness increases in the morning compared to the evening within any of the considered groups in both rest and sympathetic activation conditions. There are differences between the sexes, which vary according to age and diabetes status. In particular, aortic stiffness is higher in older women than in men with diabetes during acute stress.

Ideal Life’s Simple 7 Score Relates to Macrovascular Structure and Function in the Healthy Population

Background: Cardiovascular health scores, such as Life’s Simple 7 from the American Heart Association, and the assessment of arterial properties are independently used to determine cardiovascular risk. However, evidence of their association remains scarce, especially in healthy, middle-aged to older populations. Methods: A healthy sample of the Swiss population aged 50–91 years as part of the COmPLETE cohort study was included. Carotid intima–media thickness (cIMT), carotid lumen diameter (cLD), carotid distensibility coefficient (DC), flow-mediated dilation (FMD), and brachial–ankle pulse wave velocity (baPWV) were used to determine arterial properties. The Life’s Simple 7 cardiovascular health score was calculated using seven categories (body-mass index, cholesterol, systolic blood pressure, hemoglobin A1c, smoking status, physical activity, and diet). In accordance with the American Heart Association, for each category, two points were given for an ideal health metric level, intermediate scores one point, and poor scores zero points. Intermediate and ideal health scores corresponded to a total of 5–9 and 10–14 points, respectively. Results: A total of 280 participants (50.7% male) were included. After adjusting for age and sex, an ideal health score was associated with lower cIMT (−0.038 mm, 95% CI: −0.069 mm–−0.007 mm, p = 0.017), lower cLD (−0.28 mm, 95% CI: −0.46 mm–−0.11 mm, p = 0.002), and lower baPWV (−0.05 m/s, 95% CI: −0.08 m/s–−0.02 m/s, p = 0.003). No differences were found for FMD and DC. Conclusions: Even in a healthy sample of middle-aged and older adults, individuals with an ideal cardiovascular health score showed more favorable biomarkers of vascular aging than those with an intermediate score. This stresses the relevance of promoting an optimal lifestyle, even among the healthy population.

Predictive Value of the Cardio-Ankle Vascular Index for Cardiovascular Events in Patients at Cardiovascular Risk

Background Arterial stiffness is an important predictor of cardiovascular events; however, indexes for measuring arterial stiffness have not been widely incorporated into routine clinical practice. This study aimed to determine whether the cardio-ankle vascular index (CAVI), based on the blood pressure-independent stiffness parameter β and reflecting arterial stiffness from the origin of the ascending aorta, is a good predictor of cardiovascular events in patients with cardiovascular disease risk factors in a large prospective cohort. Methods and Results This multicenter prospective cohort study, commencing in May 2013, with a 5-year follow-up period, included patients (aged 40‒74 years) with cardiovascular disease risks. The primary outcome was the composite of cardiovascular death, nonfatal stroke, or nonfatal myocardial infarction. Among 2932 included patients, 2001 (68.3%) were men; the mean (SD) age at diagnosis was 63 (8) years. During the median follow-up of 4.9 years, 82 participants experienced primary outcomes. The CAVI predicted the primary outcome (hazard ratio, 1.38; 95% CI, 1.16‒1.65; P<0.001). In terms of event subtypes, the CAVI was associated with cardiovascular death and stroke but not with myocardial infarction. When the CAVI was incorporated into a model with known cardiovascular disease risks for predicting cardiovascular events, the global χ² value increased from 33.8 to 45.2 (P<0.001), and the net reclassification index was 0.254 (P=0.024). Conclusions This large cohort study demonstrated that the CAVI predicted cardiovascular events. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01859897.

Functional aging in health and heart failure: the COmPLETE Study

BACKGROUND

Cardiovascular (CV) diseases including heart failure are the leading causes of morbidity, with age being the primary risk factor. The combination of age-related organic functional impairment and reduced physical fitness can drastically impact an individual's healthspan. One's lifespan can potentially be prolonged by the preservation or improvement of physical fitness. However, it remains unclear as to which biomarkers are most suitable for distinguishing between healthy aging and the impaired organ function associated with heart failure. Therefore, a comprehensive assessment of the components of physical fitness and CV function will be performed to identify the most important factors contributing to aging in relation to both health and disease.

METHODS

This cross-sectional investigation will consist of two parts: COmPLETE-Health (C-Health) and COmPLETE-Heart (C-Heart). C-Health will examine the aging trajectories of physical fitness components and CV properties in a healthy population sample aged between 20 and 100 years (n = 490). Separately, C-Heart will assess the same markers in patients at different stages of chronic heart failure (n = 80). The primary outcome to determine the difference between C-Health and C-Heart will be cardiorespiratory fitness as measured by cardiopulmonary exercise testing on a bicycle ergometer. Secondary outcomes will include walking speed, balance, isometric strength, peak power, and handgrip strength. Physical activity as a behavioural component will be assessed objectively via accelerometry. Further, CV assessments will include pulse wave velocity; retinal, arterial, and venous diameters; brachial and retinal arterial endothelial function; carotid intima-media thickness; and systolic and diastolic function. The health distances for C-Health and C-Heart will be calculated using the methodology based on statistical (Mahalanobis) distance applied to measurements of quantitative biomarkers.

DISCUSSION

This research seeks to identify physical fitness and CV biomarkers that best resemble underlying CV risk with age. Further, it will examine which physical fitness markers are impaired most in heart failure. The presented integrative approach could define new recommendations for diagnostic guidance in aging. Ultimately, this study is expected to offer a better understanding of which functional characteristics should be specifically targeted in primary and secondary prevention to achieve an optimal healthspan.

Effects of metabolic syndrome on arterial function in different age groups: the Advanced Approach to Arterial Stiffness study

OBJECTIVE

The aim of the Advanced Approach to Arterial Stiffness study was to compare arterial stiffness measured simultaneously with two different methods in different age groups of middle-aged and older adults with or without metabolic syndrome (MetS). The specific effects of the different MetS components on arterial stiffness were also studied.

METHODS

This prospective, multicentre, international study included 2224 patients aged 40 years and older, 1664 with and 560 without MetS. Patients were enrolled in 32 centres from 18 European countries affiliated to the International Society of Vascular Health & Aging. Arterial stiffness was evaluated using the cardio-ankle vascular index (CAVI) and the carotid-femoral pulse wave velocity (CF-PWV) in four prespecified age groups: 40-49, 50-59, 60-74, 75-90 years. In this report, we present the baseline data of this study.

RESULTS

Both CF-PWV and CAVI increased with age, with a higher correlation coefficient for CAVI (comparison of coefficients P < 0.001). Age-adjusted and sex-adjusted values of CF-PWV and CAVI were weakly intercorrelated (r = 0.06, P < 0.001). Age-adjusted and sex-adjusted values for CF-PWV but not CAVI were higher in presence of MetS (CF-PWV: 9.57 ± 0.06 vs. 8.65 ± 0.10, P < 0.001; CAVI: 8.34 ± 0.03 vs. 8.29 ± 0.04, P = 0.40; mean ± SEM; MetS vs. no MetS). The absence of an overall effect of MetS on CAVI was related to the heterogeneous effects of the components of MetS on this parameter: CAVI was positively associated with the high glycaemia and high blood pressure components, whereas lacked significant associations with the HDL and triglycerides components while exhibiting a negative association with the overweight component. In contrast, all five MetS components showed positive associations with CF-PWV.

CONCLUSION

This large European multicentre study reveals a differential impact of MetS and age on CAVI and CF-PWV and suggests that age may have a more pronounced effect on CAVI, whereas MetS increases CF-PWV but not CAVI. This important finding may be due to heterogeneous effects of MetS components on CAVI. The clinical significance of these original results will be assessed during the longitudinal phase of the study.

Effects of exercise intensity and cardiorespiratory fitness on the acute response of arterial stiffness to exercise in older adults

PURPOSE

Increased arterial stiffness is observed with ageing and in individuals with low cardiorespiratory fitness ([Formula: see text]O_2peak), and associated with cardiovascular risk. Following an exercise bout, transient arterial stiffness reductions offer short-term benefit, but may depend on exercise intensity. This study assessed the effects of exercise intensity on post-exercise arterial stiffness in older adults with varying fitness levels.

METHODS

Fifty-one older adults (72 ± 5 years) were stratified into fitness tertiles ([Formula: see text]O_2peak: low-, 22.3 ± 3.1; mid-, 27.5 ± 2.4 and high-fit 36.3 ± 6.5 mL kg^-1 min^-1). In a randomised order, participants underwent control (no-exercise), moderate-intensity continuous exercise (40% of peak power output; PPO), and higher-intensity interval exercise (70% of PPO) protocols. Pulse wave velocity (PWV), augmentation index (AIx75) and reflection magnitude (RM) were assessed at rest and during 90 min of recovery following each protocol.

RESULTS

After control, delta PWV increased over time (P < 0.001) and delta RM was unchanged. After higher-intensity interval exercise, delta PWV (P < 0.001) and delta RM (P < 0.001) were lower to control in all fitness groups. After moderate-intensity continuous exercise, delta PWV was not different from control in low-fit adults (P = 0.057), but was lower in the mid- and higher-fit older adults. Post-exercise AIx75 was higher to control in all fitness groups (P = 0.001).

CONCLUSIONS

In older adults, PWV increases during seated rest and this response is attenuated after higher-intensity interval exercise, regardless of fitness level. This attenuation was also observed after moderate-intensity continuous exercise in adults with higher, but not lower fitness levels. Submaximal exercise reveals differences in the arterial stiffness responses between older adults with higher and lower cardiorespiratory fitness.

Improved assessment of arterial stiffness using corrected cardio-ankle vascular index (CAVI0) in overweight adolescents with white-coat and essential hypertension

Arterial stiffness is a marker of vascular damage. Although adiposity increases cardiovascular risk, the relationship between paediatric overweight and arterial stiffness is unclear. The study aimed to evaluate the simultaneous effect of hypertension and overweight on arterial stiffness using cardio-ankle vascular index (CAVI) and related novel, theoretically blood pressure (BP)-independent, index CAVI₀. CAVI and CAVI₀ were measured in 140 adolescent boys (16.0 ± 1.9 years) divided into age-matched groups: normal-weight normotensives, overweight normotensives, overweight white-coat hypertensives, and overweight essential hypertensives. Overweight normotensives had significantly lower CAVI and CAVI₀ compared to normal-weight normotensives (4.81 ± 0.64 vs. 5.33 ± 0.66, p < .01; 7.10 ± 0.99 vs. 7.81 ± 1.00, p < .01, respectively). CAVI and CAVI₀ in overweight essential hypertensives showed no significant difference compared to normal-weight normotensives and were significantly higher compared to overweight normotensives (5.32 ± 0.77 vs. 4.81 ± 0.64, p < .01; 7.77 ± 1.19 vs. 7.10 ± 0.99, p < .01, respectively). CAVI, but not CAVI₀, was associated positively with diastolic pressure (0.022 mmHg^-1, p = .002) and negatively with pulse pressure (-0.022 mmHg^-1, p = .001), and it was significantly higher in overweight white-coat hypertensives compared to overweight normotensives (5.20 ± 0.63 vs. 4.81 ± 0.64, p < .05). The lowering effect of overweight on arterial stiffness indexed by CAVI and CAVI₀ in hypertensive adolescents seems to counterbalance the early arteriosclerotic effect of essential hypertension. The increase in CAVI, but not CAVI₀, in overweight white-coat hypertensives could be attributable to residual BP dependence of CAVI, which is not present in CAVI₀. Under certain conditions, CAVI₀ may offer a clinically relevant improved assessment of arterial stiffness superior to CAVI.

Ambulatory Aortic Stiffness Is Associated With Narrow Retinal Arteriolar Caliber in Hypertensives: The SAFAR Study

BACKGROUND

Arterial stiffness measured under static conditions reclassifies significantly cardiovascular (CV) risk and associates with narrower retinal arterioles. However, arterial stiffness exhibits circadian variation, thus single static stiffness recordings do not correspond to the "usual" 24 hr, awake, and asleep average arterial stiffness. We aimed to test the hypothesis that ambulatory 24 hr, awake, and asleep aortic (a) pulse wave velocity (PWV) associate with retinal vessel calibers, independently of confounders and of static arterial stiffness, in hypertensive individuals free from diabetes and CV disease.

METHODS

Digital retinal images were obtained (181 individuals, age: 53.9±10.7 years, 55.2% men) and retinal vessel calibers were measured with validated software to determine central retinal arteriolar and venular equivalents (CRAE and CRVE, respectively); ambulatory (24 hr, awake, asleep) and static office aPWV were estimated by Mobil-O-Graph; and static office carotid to femoral (cf) PWV by SphygmoCor.

RESULTS

Regression analysis performed in 320 gradable retinal images showed that, after adjustment for confounders: (i) ambulatory aPWV was significantly associated with narrower retinal arterioles but not with venules; (ii) asleep aPWV had stronger associations with CRAE than awake aPWV; (iii) both ambulatory aPWV and cfPWV were associated mutually independently with narrower retinal arterioles; aPWV introduction in the model of cfPWV, improved model's R2 (P = 0.012). Similar discriminatory ability of 24 hr aPWV and of cfPWV to detect the presence of retinal arteriolar narrowing was found.

CONCLUSION

Ambulatory aPWV, estimated by an operator-independent method, provides additional information to cfPWV regarding the associations of arterial stiffness with the retinal vessel calibers.

Assessment of Arterial Stiffness Using the Cardio-Ankle Vascular Index

BACKGROUND

Arterial stiffness is an independent predictor of outcomes for patients with cardiovascular disease. Although measurement of pulse wave velocity is a widely accepted, noninvasive approach for the assessment of arterial stiffness, its accuracy is affected by changes in blood pressure.

SUMMARY

The cardio-ankle vascular index (CAVI) is an index of the overall stiffness of the artery from the origin of the aorta to the ankle and is theoretically independent of blood pressure at the time of measurement. CAVI increases linearly with age and is elevated even in mild arteriosclerotic disease. It can identify differences in the degree of arteriosclerosis among patients with severe arteriosclerotic disease and better reflects the severity of disease of the coronary artery than does brachial-ankle pulse wave velocity. Patients with higher CAVI values show a poor prognosis compared with those with lower CAVI values. Furthermore, CAVI can be lowered by controlling diabetes mellitus and hypertension.

KEY MESSAGES

The primary aims of assessing arterial stiffness using CAVI are to assist in the early detection of arteriosclerosis, allowing timely treatment and lifestyle modification, and to quantitatively evaluate the progression of disease and the effectiveness of treatment. Whether CAVI-guided therapy can improve prognosis in high-risk patients needs to be further examined to confirm the clinical usefulness of this measure.

Cardio-ankle vascular index predicts for the incidence of cardiovascular events in obese patients: a multicenter prospective cohort study (Japan Obesity and Metabolic Syndrome Study: JOMS)

OBJECTIVE

The cardio-ankle vascular index (CAVI) is an index of arterial stiffness less dependent on blood pressure and an indicator suitable for assessing the arterial dysfunction. However, it remains unclear whether CAVI can predict the outcome of cardiovascular diseases (CVD) in obese patients.

METHODS

A total of 425 obese Japanese outpatients (189 men and 236 women, mean age: 51.5 years) were enrolled in a multicenter prospective cohort Japan, the Japan Obesity and Metabolic Syndrome Study (JOMS). Primary analysis regarding measurements of cardiovascular risk factors including CAVI and the occurrence of macrovascular complications was based on following the participants over a 5-year period.

RESULTS

Of the eligible patients, 300 (78%) were followed into the fifth year. During the study period, 15 coronary heart disease, 7 stroke, and 6 arteriosclerosis obliterans events occurred. All events occurred in 28 patients, and CVD incidence rate was 15.8 per 1000 person-years. In the analysis of adjusted models for traditional risk factors, CAVI was a significant factor for the incidence of events. In addition, high CAVI and low HDL-cholesterol were significant factors for the incidence of events in Cox stepwise multivariate analysis when age- and sex-adjusted (CAVI [per 1]: HR = 1.44 [1.02-2.02], p = 0.037; HDL-cholesterol [per 1 mmol/L]: HR = 0.20 [0.06-0.69], p = 0.011). In addition, CAVI added value to atherosclerotic cardiovascular disease risk score in predicting the development of CVD.

CONCLUSION

This study demonstrates for the first time that CAVI is an effective predictor of CVD events in obese patients.

Physical activity is associated with lower arterial stiffness in older adults: results of the SAPALDIA 3 Cohort Study

Associations of physical activity (PA) intensity with arterial stiffness in older adults at the population level are insufficiently studied. We examined cross-sectional associations of self-reported PA intensities with arterial stiffness in elderly Caucasians of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults. Mixed central and peripheral arterial stiffness was measured oscillometrically by the cardio-ankle vascular index (CAVI) and brachial-ankle pulse wave velocity (baPWV). The self-reported International Physical Activity Questionnaire long version was administered to classify each subject's PA level. We used univariable and multivariable mixed linear and logistic regression models for analyses in 1908 persons aged 50 years and older. After adjustment for several confounders moderate, vigorous and total PA were inversely associated with CAVI (p = 0.02-0.03). BaPWV showed negative and marginally significant associations with vigorous and moderate PA (each p = 0.06), but not with total PA (p = 0.28). Increased arterial stiffness (CAVI ≥ 9, upper tertile) was inversely and significantly associated with vigorous PA [odds ratio (OR) 0.65, 95% confidence interval (CI) 0.48-0.88], and marginally significantly with total PA (OR 0.76, 95% CI 0.57-1.02) and moderate PA (OR 0.75, 95% CI 0.56-1.01). The odds ratio for baPWV ≥ 14.4 was 0.67 (95% CI 0.48-0.93) across the vigorous PA levels, and was non-significant across the total (OR 0.91, 95% CI 0.66-1.23) and moderate PA levels (OR 0.94, 95% CI 0.69-1.28). In this general Caucasian population of older adults higher levels especially of vigorous PA were associated with lower arterial stiffness. These data support the importance of PA for improving cardiovascular health in elderly people.

Reproducibility of oscillometrically measured arterial stiffness indices: Results of the SAPALDIA 3 cohort study

BACKGROUND

There is an increasing interest in oscillometric arterial stiffness measurement for cardiovascular risk stratification. We assessed reproducibility of the cuff-based arterial stiffness measures cardio-ankle vascular index (CAVI), brachial-ankle pulse wave velocity (baPWV) and peripheral augmentation index (pAI) in a subsample of the second follow-up of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA 3).

METHODS

CAVI, baPWV and pAI were measured twice within 90 days in a representative subsample (n = 105) of SAPALDIA 3 with a mean age of 63 years (52.4% female).

RESULTS

The mean coefficient of variation for CAVI was 4.4%, baPWV 3.9%, and pAI 7.4%. The intraclass correlation coefficient ranged from 0.6 for pAI to 0.8 for CAVI, and 0.9 for baPWV. The mixed linear model revealed that 68.7%/80.1%/55.0% of the CAVI/baPWV/pAI variance was accounted for by the subject, 5.2%/8.1%/ < 0.01% by the fieldworker, 6.7%/7.8%/28.5% by variation between measurement days, and 19.4%/4%/16.5% by measurement error. Bland-Altman plots showed no particular dispersion patterns except for pAI.

CONCLUSIONS

Oscillometric arterial stiffness measurement by CAVI and baPWV has proved to be highly reproducible in Caucasians. Results of the pAI showed lower reproducibility. CAVI and baPWV can be implemented as easy-to-apply arterial stiffness measures in population wide cardiovascular risk assessment in Caucasians.