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

Cardio-Ankle Vascular Index and Aging: Differences between CAVI and CAVI0

BACKGROUND

Cardio-ankle vascular index (CAVI) and CAVI0 (a mathematical expression derived from CAVI, supposed to be less dependent on blood pressure), can describe arterial stiffness, considering a wide proportion of the arterial tree. The aim of this study was to examine the relationship between CAVI, CAVI0 and aging, looking at the differences between the two arterial stiffness indexes.

METHODS

A total of 191 patients (68 male, mean age 68.3 ± 14.4 years) referred to the Geriatric Ward and Outpatient Clinic at Verona University Hospital were included and underwent a comprehensive clinical evaluation. CAVI and CAVI0 were obtained for each.

RESULTS

CAVI0 steeply rises in the elderly age strata, widening the gap between CAVI and CAVI0. An inverse relationship is evident between CAVI0 and DBP in older patients, and CAVI0 is shown to be dependent on age, DBP and age-DBP interaction (R2 = 0.508). Age modifies the effect of DBP on CAVI0, but not on CAVI.

CONCLUSIONS

The real new findings of our study are that the association between CAVI0 and diastolic blood pressure (DBP) is modified by age, whereas the association between CAVI and DBP is not modified by age. From a clinical point of view, these are very important findings, as DBP decreases with aging, affecting in elderly populations the reliability of CAVI0, which strictly depends on DBP in the formula to calculate it. To monitor the effect of CV therapies, progression of CV diseases and to evaluate clinical outcomes in elderly populations, we suggest using CAVI and not CAVI0.

Five years of cardio-ankle vascular index (CAVI) and CAVI0: how close are we to a pressure-independent index of arterial stiffness?

Pulse wave velocity, a common metric of arterial stiffness, is an established predictor for cardiovascular events and mortality. However, its intrinsic pressure-dependency complicates the discrimination of acute and chronic impacts of increased blood pressure on arterial stiffness. Cardio-ankle vascular index (CAVI) represented a significant step towards the development of a pressure-independent arterial stiffness metric. However, some potential limitations of CAVI might render this arterial stiffness metric less pressure-independent than originally thought. For this reason, we later introduced CAVI0. Nevertheless, advantages of one approach over the other are left debated. This review aims to shed light on the pressure (in)dependency of both CAVI and CAVI0. By critically reviewing results from studies reporting both CAVI and CAVI0 and using simple analytical methods, we show that CAVI0 may enhance the pressure-independent assessment of arterial stiffness, especially in the presence of large inter-individual differences in blood pressure.

The impacts of exercise on pediatric obesity

Over the last few decades, the rates of pediatric obesity have more than doubled regardless of sociodemographic categorization, and despite these rates plateauing in recent years there continues to be an increase in the severity of obesity in children and adolescents. This review will discuss the pediatric obesity mediated cardiovascular disease (CVD) risk factors such as attenuated levels of satiety and energy metabolism hormones, insulin resistance, vascular endothelial dysfunction, and arterial stiffness. Additionally, early intervention to combat pediatric obesity is critical as obesity has been suggested to track into adulthood, and these obese children and adolescents are at an increased risk of early mortality. Current suggested strategies to combat pediatric obesity are modifying diet, limiting sedentary behavior, and increasing physical activity. The effects of exercise intervention on metabolic hormones such as leptin and adiponectin, insulin sensitivity/resistance, and body fat in obese children and adolescents will be discussed along with the exercise modality, intensity, and duration. Specifically, this review will focus on the differential effects of aerobic exercise, resistance training, and combined exercise on the cardiovascular risks in pediatric obesity. This review outlines the evidence that exercise intervention is a beneficial therapeutic strategy to reduce the risk factors for CVD and the ideal exercise prescription to combat pediatric obesity should contain both muscle strengthening and aerobic components with an emphasis on fat mass reduction and long-term adherence.

A randomised, factorial trial to reduce arterial stiffness independently of blood pressure: Proof of concept? The VaSera trial testing dietary nitrate and spironolactone

AIMS

To test if spironolactone or dietary nitrate from beetroot juice could reduce arterial stiffness as aortic pulse wave velocity (PWVart), a potential treatment target, independently of blood pressure.

METHODS

Daily spironolactone (≤50 mg) vs doxazosin (control ≤16 mg) and 70 mL beetroot juice (Beet-It ≤11 mmol nitrate) vs nitrate-depleted juice (placebo; 0 mmol nitrate) were tested in people at risk or with type-2 diabetes using a double-blind, 6-month factorial trial. Vascular indices (baseline, 12, 24 weeks) were cardiac-ankle vascular index (CAVI), a nominally pressure-independent stiffness measure (primary outcome), PWVart secondary, central systolic pressure and augmentation. Analysis was intention-to-treat, adjusted for systolic pressure differences between trial arms.

RESULTS

Spironolactone did not reduce stiffness, with evidence for reduced CAVI on doxazosin rather than spironolactone (mean difference [95% confidence interval]; 0.25 [-0.3, 0.5] units, P = .080), firmer for PWVart (0.37 [0.01, 0.7] m/s, P = .045). There was no difference in systolic pressure reduction between spironolactone and doxazosin (0.7 [-4.8, 3.3] mmHg, P = .7). Circulating nitrate and nitrite increased on active vs placebo juice, with central systolic pressure lowered -2.6 [-4.5, - 0.8] mmHg, P = .007 more on the active juice, but did not reduce CAVI, PWVart or peripheral pressure. Change in nitrate and nitrite concentrations were 1.5-fold [1.1-2.2] and 2.2-fold [1.3, 3.6] higher on spironolactone than on doxazosin respectively; both P < .05.

CONCLUSION

Contrary to our hypothesis, in at-risk/type 2 diabetes patients, spironolactone did not reduce arterial stiffness, rather PWVart was lower on doxazosin. Dietary nitrate elevated plasma nitrite, selectively lowering central systolic pressure, observed previously for nitrite.

Arterial Stiffness and Endothelial Function in Young Obese Patients - Vascular Resistance Matters

AIM

Motivated by the paradoxical and differing results of the early atherosclerosis related indices - Cardio-Ankle Vascular Index (CAVI) reflecting arterial stiffness and Reactive Hyperemia Index (RHI) evaluating endothelium dependent flow-induced vasodilation - in obesity, we aimed to assess CAVI and RHI in obese adolescents and young adults in the context of differences in systemic vascular resistance (SVR).

METHODS

We examined 29 obese (14f, 15.4 [12.3-18.5] y; BMI: 33.2±4.4 kg.m-2) and 29 non-obese gender and age matched adolescents and young adults (BMI: 21.02±2.3 kg.m-2). CAVI and RHI were measured using VaSera VS-1500 (Fukuda Denshi, Japan) and Endo-PAT 2000 (Itamar Medical, Israel), respectively. Hemodynamic measures were recorded using volume-clamp plethysmography (Finometer Pro, FMS, Netherlands) and impedance cardiography (CardioScreen 2000, Medis GmbH, Germany). SVR and sympathetic activity related indices - Velocity Index (VI) and Heather Index (HI), and LFSAP (spectral power in low frequency band of systolic blood pressure oscillations) were determined.

RESULTS

In obese group, CAVI (4.59±0.88 vs. 5.18±0.63, p=0.002) and its refined version CAVI0 (6.46±1.39 vs.7.33±0.99, p=0.002) were significantly lower. No significant difference in RHI was found. SVR and sympathetic activity indices were all significantly lower in the obese group than in the non-obese group. RHI correlated positively with SVR (r=0.390, p=0.044) in obese subjects.

CONCLUSION

Our results indicate that both indices used for the detection of early atherosclerotic changes are influenced by vascular tone. Vascular resistance could influence CAVI and RHI results impairing their interpretation.

Novel Biomarkers of Early Atherosclerotic Changes for Personalised Prevention of Cardiovascular Disease in Cervical Cancer and Human Papillomavirus Infection

Cervical cancer is associated with a causative role of human papillomavirus (HPV), which is a highly prevalent infection. Recently, women with a genital HPV infection were found to have increased incidence of cardiovascular diseases (CVD), including severe cardiovascular events such as myocardial infarction and stroke. The pathomechanisms of this relation are not yet fully understood, and may significantly affect the health of a large part of the population. Accelerated atherosclerosis is assumed to play a key role in the pathophysiology of this relationship. To identify high-risk groups of the population, it is necessary to stratify the CVD risk. Current algorithms, as widely used for the estimation of CVD risk, seem to be limited by the individual misclassification of high-risk subjects. However, personalised prediction of cardiovascular events is missing. Regarding HPV-related CVD, identification of novel sensitive biomarkers reflecting early atherosclerotic changes could be of major importance for such personalised cardiovascular risk prediction. Therefore, this review focuses on the pathomechanisms leading to HPV-related cardiovascular diseases with respect to atherosclerosis, and the description of potential novel biomarkers to detect the earliest atherosclerotic changes important for the prevention of CVD in HPV infection and cervical cancer.

Arterial stiffness and haemodynamic regulation in adolescent anorexia nervosa versus obesity

Cardiovascular complications contribute to higher morbidity and mortality in patients with anorexia nervosa. We aimed to study biomarkers of cardiovascular risk in anorexic, normal-weight, and obese adolescents with focus on complex cardiovascular autonomic regulation and early arteriosclerotic damage. We examined 20 adolescent girls with anorexia nervosa, 20 obese girls, and 20 healthy normal-weight controls. Collected data: body composition analysis, 5 min recordings of R-R intervals and beat-to-beat blood pressure (BP), and arterial stiffness evaluated using cardio-ankle vascular index (CAVI). Evaluated parameters: beat-to-beat heart rate and BP variability, haemodynamic parameters (total peripheral resistance (TPR) cardiac output), CAVI, and anthropometric indices, including novel body roundness index (BRI). Adolescents with anorexia nervosa had increased CAVI associated with lower arterial constriction indexed by low-frequency band of BP variability compared with normal-weight peers (p = 0.03, p = 0.04, respectively) and obese adolescents (p < 0.01, p = 0.01, respectively). After normalization of CAVI and TPR by BRI, the relationship between CAVI and TPR was significant for all groups with the highest slope in the anorexia nervosa group (R² = 0.724, p < 0.01). This is the first study revealing early arteriosclerotic damage in anorexic girls with increased CAVI. Complex analysis of cardiovascular autonomic regulation, and early arteriosclerotic, hemodynamic, and anthropometric changes in spectrum anorexia nervosa, normal weight, and obesity could help to understand the mechanisms of increased cardiovascular risk in malnutrition. Novelty Girls with anorexia nervosa showed signs of early arteriosclerotic damage indexed by CAVI. Insufficient sympathetic cardiovascular control was found already in adolescents with anorexia nervosa. The effect of body composition on CAVI was best predicted by novel body roundness index.

Comparison of Cardio-Ankle Vascular Index (CAVI) and CAVI0 in Large Healthy and Hypertensive Populations

Aim: The cardio-ankle vascular index (CAVI) represents the blood pressure-independent arterial stiffness from the origin of the aorta to the ankle. CAVI₀ has been proposed as a variant index. We aimed to clarify the difference between CAVI and CAVI₀ among large populations, and to explore reasons of the difference.

Methods: The subjects were 5,293 Japanese healthy and 3,338 hypertensive people. Simple and multiple regression analyses were performed using age, sex, body mass index, systolic, and diastolic blood pressure (Pd) as variables. Sub-group analysis was performed by sex and age. The CAVI values with and without adjustment by reference pressure were also compared.

Results: CAVI had a positive correlation with Pd, while CAVI₀ had a negative correlation with Pd in the healthy population. The CAVI values of the hypertensive group were higher than those of healthy group in both men and women, but the CAVI₀ values in women of the hypertensive group in the 30–39 age group was significantly lower than that of the corresponding healthy group. Differences of CAVI values with or without modification using the reference pressure were 1.09% ± 1.38% for the healthy group and 3.68% ± 1.66% for the hypertensive group.

Conclusion: CAVI showed the expected values, but CAVI₀ showed inexplicable results in the healthy and hypertensive populations. The differences were due to the strong dependency of CAVI₀ on Pd. Differences of CAVI values with or without reference pressure were negligible. These results indicate that CAVI obtained by the VaSera system is appropriate, but CAVI₀ is not.

Arterial stiffness measured by cardio-ankle vascular index in Korean women with polycystic ovary syndrome

Many studies have reported an increased arterial stiffness using pulse wave velocity (PWV) in women with polycystic ovary syndrome (PCOS). However, PWV is essentially dependent on blood pressure (BP) at the time of measurement. The cardio-ankle vascular index (CAVI) is a relatively new index for measuring arterial stiffness, and its conspicuous feature is its independency from the BP at the time of measurement. The aim of this study was to evaluate arterial stiffness by CAVI in PCOS patients (n = 26) and in the age-matched controls (n = 59). The CAVI was measured by a single medical professional. The mean age of the women with PCOS was 33.3 (±6.6) years, and that of the matched controls was 33.1 (±5.9) years (p = .861). The mean CAVIs were similar between the patients and controls (6.49 ± 0.41 and 6.39 ± 0.65, respectively, p = .452). The CAVI increased linearly with age in both groups, but in the women with PCOS, CAVI showed relatively strong negative correlations with body mass index (BMI) in both the unadjusted (r = -0.537, p = .005) and adjusted models (r = -0.474, p = .003 after age and BMI adjustment and r = -0.604, p = .033 after age, BMI, sitting auscultatory systolic BP and square root hs-CRP adjustment). In conclusion, relatively young women with PCOS may not have increased arterial stiffness. A negative correlation between CAVI and BMI in women with PCOS requires further study to determine whether vascular adaptation to adiposity occurred in these women. Impact Statement What is already known on this subject? Increased arterial stiffness is one of the earliest adverse structural and functional alterations in blood vessels, potentially leading to later cardiovascular disease. Many studies have reported an increased arterial stiffness using pulse wave velocity (PWV) in women with polycystic ovary syndrome (PCOS). However, PWV is essentially dependent on blood pressure (BP) at the time of measurement. The cardio-ankle vascular index (CAVI) is a relatively new index for measuring arterial stiffness, and its conspicuous feature is its independency from the BP at the time of measurement. What do the results of this study add? The CAVIs were similar between the women with PCOS and the age-matched controls. The CAVI increased linearly with age in both groups, but in women with PCOS, CAVI showed a relatively strong negative correlation with the body mass index (BMI). What are the implications of these findings for clinical practice and/or further research? Relatively young women with PCOS may not have increased arterial stiffness. However, CAVI showed a negative correlation with BMI only in the women with PCOS, suggesting that adiposity itself is associated with the decreased arterial stiffness in these women. This finding requires a replication, and whether adaptation to the hemodynamic consequences of adiposity occurred in the PCOS patients remains to be established. Further longitudinal studies are needed to verify the relationships among vascular stiffness, adiposity and PCOS.

Pediatric reference values for arterial stiffness parameters cardio-ankle vascular index and CAVI0

The process of arteriosclerosis begins early in life, and cardiovascular risk factors identified in childhood tend to persist into adulthood. Cardio-ankle vascular index (CAVI), a recent parameter of arterial stiffness, is considered an independent predictor of cardiovascular risk. However, there are no studies reporting sex- and age-specific physiological values of CAVI in childhood. We aimed to establish reference values for CAVI and its blood pressure-corrected variant (CAVI₀) in 500 healthy children and adolescents aged 7 to 19 years and to study potential relationships with anthropometric indices. Sex- and age-specific distributions of CAVI and CAVI₀ values in healthy children and adolescents are presented. Boys aged 15-19 years had lower CAVI than girls, which could result from CAVI's slight blood pressure dependence. CAVI₀ did not show such sex difference. Body roundness index-a novel parameter to quantify abdominal fat-was a strong anthropometric predictor of both CAVI and CAVI₀. This is the first study providing pediatric age- and sex-specific reference values for arterial stiffness parameters CAVI and CAVI₀. The presented data can contribute to the understanding of the evolution of these indices during childhood and adolescence. Under specific conditions, CAVI₀ may offer more robust information about arterial stiffness than standard CAVI.