Methods to evaluate arterial structure and function in children - State-of-the art knowledge

BACKGROUND

With increasing rates of hypertension, obesity, and diabetes in the pediatric population, wide available, and reproducible methods are necessary to evaluate arterial structure and function in children and adolescents.

METHODS

MEDLINE/Pubmed was searched for articles published in years 2012-2017 on methodology of, current knowledge on, and limitations of the most commonly used methods to evaluate central, proximal and coronary arteries, as well as endothelial function in pediatric patients.

RESULTS

Among 1528 records screened (including 1475 records from years 2012 to 2017) 139 papers were found suitable for the review. Following methods were discussed in this review article: ultrasound measurements of the intima-media thickness, coronary calcium scoring using computed tomography, arterial stiffness measurements (pulse wave velocity and pulse wave analysis, carotid artery distensibility, pulse pressure, and ambulatory arterial stiffness index), ankle-brachial index, and methods to evaluate vascular endothelial function (flow-mediated vasodilation, peripheral arterial tonometry, Doppler laser flowmetry, and cellular and soluble markers of endothelial dysfunction).

CONCLUSIONS

Ultrasonographic measurement of carotid intima-media thickness and measurement of pulse wave velocity (by oscillometry or applanation tonometry) are highly reproducible methods applicable for both research and clinical practice with proved applicability for children aged ≥6 years or with height ≥120cm. Evaluation of ambulatory arterial stiffness index by ambulatory blood pressure monitoring is another promising option in pediatric high-risk patients. Clearly, further studies are necessary to evaluate usefulness of these and other methods for the detection of subclinical arterial damage in children.

Cigarette smoking and albuminuria are associated with impaired arterial smooth muscle function in patients with type 2 diabetes mellitus: a FIELD substudy

AIM

Impaired arterial function has been implicated in diabetes-related atherosclerosis, but its determinants in high-risk adults have not been well characterised. We investigated factors associated with impaired arterial function in adults with type 2 diabetes.

METHODS

Flow-mediated dilatation (a marker of endothelial function) and dilator response to glyceryl trinitrate (to assess smooth muscle function) of the brachial artery were assessed at baseline in 193 patients with type 2 diabetes from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study. Traditional risk factors were assessed and a multivariable model was constructed to identify factors independently associated with impaired arterial function.

RESULTS

Median age was 64 years (interquartile range, 58-69; 61% male) and duration of diabetes was 4 years (interquartile range, 2-9). Flow-mediated dilatation (3.06 ± 0.25%, mean ± SEM) was severely impaired but not significantly associated with other risk factors. Dilator responses to glyceryl trinitrate (10.56 ± 0.52%) were significantly and independently impaired in past and present cigarette smokers (P = 0.005) and in subjects with increased urinary albumin/creatinine ratio (P = 0.01).

CONCLUSIONS

In adults with type 2 diabetes and known or suspected atherosclerosis, arterial smooth muscle-dependent dilatation was shown to be significantly impaired in cigarette smokers and those with elevated urinary albumin levels.

The physiological benefits of sitting less and moving more: Opportunities for future research

Sedentary behavior (SB) and physical activity (PA) are important risk factors of cardiovascular disease morbidity and mortality. In addition to increasing the amount of moderate-to-vigorous PA (MVPA), the current PA guidelines recommend that adults should reduce SB, or any waking activity performed while sitting, reclining, or lying, with low energy expenditure. While mounting evidence has emphasized the benefits of increasing MVPA, little has focused on the effect of SB on health. Therefore, this review discusses the pathophysiological effects of SB and the potential physiological benefits of reducing/breaking up SB at the levels below the current guidelines for PA. Such knowledge is important, given that the majority of the United States population performs insufficient or no MVPA and is at high risk of being negatively impacted by SB. Interventions targeting sedentary time, such as breaking up SB by standing and moving, may be safe, feasible, and applicable to execute daily for a wide range of the population. This review also discusses the importance of monitoring SB in the era of the coronavirus disease 2019 (COVID-19) pandemic and the clinical implications of sitting less and moving more.

Aging, aerobic exercise, and cardiovascular health: Barriers, alternative strategies and future directions

Age-associated cardiovascular (CV) dysfunction, namely arterial dysfunction, is a key antecedent to the development of CV disease (CVD). Arterial dysfunction with aging is characterized by impaired vascular endothelial function and stiffening of the large elastic arteries, each of which is an independent predictor of CVD. These processes are largely mediated by an excess production of reactive oxygen species (ROS) and an increase in chronic, low-grade inflammation that ultimately leads to a reduction in bioavailability of the vasodilatory molecule nitric oxide. Additionally, there are other fundamental aging mechanisms that may contribute to excessive ROS and inflammation termed the "hallmarks of aging"; these additional mechanisms of arterial dysfunction may represent therapeutic targets for improving CV health with aging. Aerobic exercise is the most well-known and effective intervention to prevent and treat the effects of aging on CV dysfunction. However, the majority of mid-life and older (ML/O) adults do not meet recommended exercise guidelines due to traditional barriers to aerobic exercise, such as reduced leisure time, motivation, or access to fitness facilities. Therefore, it is a biomedical research priority to develop and implement time- and resource-efficient alternative strategies to aerobic exercise to reduce the burden of CVD in ML/O adults. Alternative strategies that mimic or are inspired by aerobic exercise, that target pathways specific to the fundamental mechanisms of aging, represent a promising approach to accomplish this goal.

Sex and Gender Aspects in Vascular Ageing - Focus on Epidemiology, Pathophysiology, and Outcomes

Sex and gender are important modifiers of cardiovascular system physiology, pathophysiology, and disease development. The atherosclerosis process, together with the progressive loss of arterial elasticity with age, is a major factor influencing the development of overt cardiovascular, renal, and cerebrovascular disease. While differences between women and men in epidemiology and pathophysiology of vascular ageing are increasingly reported, sex-disaggregated data are still scarcely available for prospective studies. A better knowledge of sex differences in physiological ageing as well as in disease-related changes in vascular ageing trajectories is crucial to avoid misdiagnosis and mistreatment. This review presents key concepts and knowledge gaps identified in vascular ageing due to gonadal function, vascular physiology, pathophysiology, psychosocial factors, pregnancy, and prognostic relevance. Gender roles determine the effectiveness of any cardiovascular preventive strategy and acceptance for non-invasive or invasive diagnostics and therapeutics. Gender differences in health behaviour, also due to sociocultural norms conditioned by society, contribute to behaviours that may lead to premature arterial vascular ageing. These include differences in risk behaviours like smoking, diet, exercise, and in stress, but also conditions such as housing, noise pollution, poverty, disability, and any kind of stigmatisation. The VascAgeNet Gender Expert Group aims to advance the use of non-invasive vascular ageing measures in routine clinical settings by providing facts to fill in the gaps concerning sex and gender differences at each step of this process, and to search for solutions.

The design and rationale of the Beijing Vascular Disease Patients Evaluation Study (BEST study)

Aims

Arteriosclerosis and arterial stiffness increasing are the basic pathophysiological changes of vascular-related diseases, and also the predictor factors of future cardiovascular events. Plasma biomarkers such as glucose, lipids, Homocysteine (Hcy), N-terminal pro-brain natriuretic peptide (NT-proBNP) have been shown to be involved the development of arteriosclerosis. The present study is a prospective observational and follow-up study of the characteristics of subclinical vascular disease detected by non-invasive methods that can predict progression of clinical overt vascular events in a Chinese population.

Methods

The study including both genders with age of 45 years to 75 years was designed as observational research by questionnaires and 3-year follow-up with vascular functional and structural parameters evaluation without any interventions. Questionnaire was designed to survey the lifestyle, personal history, family history of the study population. Arterial function indexes such as pulse wave velocity, cardio-ankle vascular index, flow mediated vascular dilation, ankle brachial index, carotid intima-media thickness, and plasma biomarkers such as glucose, lipids, Hcy, NT-pro BNP, Glycosylated hemoglobin, insulin resistance index, uric acid are collected. The outcome is the composite of acute myocardial infarction or coronary reperfusion therapy or stroke or peripheral vascular diseases.

Conclusions

2858 subjects were enrolled into our present study at baseline, and this present study will provide important information on the metabolic related traditional and new risk factors, establish a new vascular disease early detection system and scoring systems based on comprehensive vascular disease risk factors and vascular function and structure evaluation indexes.

Non-invasive assessment of vascular alteration using ultrasound

It is well known that arterial function relates to cardiovascular morbidity and mortality. The noninvasive technology for the assessment of arterial function has developed as the importance of prevention of early cardiovascular disease has been emphasized. Over 2-D and Doppler echocardiography, speckle-tracking echocardiography has emerged as a valuable ultrasound imaging technique that allows for an objective and quantitative evaluation of global and regional myocardial function. Recently, several studies have extended its applicability beyond cardiac chambers, such as artery. Measurement of carotid arterial strain with speckle tracking ultrasound has been shown to be feasible and reliable. This review describes the new ultrasound techniques to assess arterial function and their clinical implications.

Associations of childhood diet quality scores with arterial stiffness and carotid artery intima-media thickness in adolescence/early adulthood: findings from the ALSPAC cohort

This study examined the relationship between childhood diet quality and arterial stiffness and thickness during adolescence/early adulthood. Participants were from the Avon Longitudinal Study of Parents and Children (ALSPAC) with dietary data at ages 7, 10 and 13 years and pulse wave velocity (PWV) and carotid intima-media thickness (cIMT) at ages 17 and/or 24 years. Diet quality (DQ) was assessed using five scores: a children's Mediterranean-style diet (C-rMED) Z-score, a children's Dietary Inflammatory Z-score (C-DIS), a DASH diet Z-score, a children's Eatwell Guide (C-EWG) Z-score reflecting UK dietary guidelines and a data-driven obesogenic Z-score. Adjusted regression models examined the associations between DQ scores at 7-13 years and PWV and cIMT at 17 and 24 years. In adjusted models, a high v. low Obesogenic Z-score at 7 and 10 years was associated with higher PWV at 17: β 0.07 (95 % CI 0.01, 0.13) and β 0.10 (95 % CI 0.04, 0.16), respectively. A high v. low C-rMED Z-score at 7 years was associated with lower PWV at 17 (β -0.07; 95 % CI -0.14, -0.01). A high (more anti-inflammatory) vs low C-DIS Z-score at 10 years was associated with a lower PWV at 17 years: β -0.06 (95 % CI -0.12, -0.01). No other associations were observed. In conclusion, an Obesogenic dietary pattern in childhood (7-10 years) was related to increased arterial stiffness, while Mediterranean-style and anti-inflammatory diets were related to decreased arterial stiffness in adolescence. This highlights the importance of establishing healthy dietary habits early in life to protect against vascular damage.

Impaired arterial responsiveness in untreated gout patients compared with healthy non-gout controls: association with serum urate and C-reactive protein

To determine whether arterial responsiveness is impaired among patients with gout, and whether arterial responsiveness inversely correlates with serum urate and inflammatory measures. This is a cross-sectional study of untreated gout subjects (n = 34) and non-gout healthy controls (n = 64). High-resolution dynamic ultrasound-measured flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD) assessed endothelium-dependent and endothelium-independent arterial responsiveness respectively. Serum urate (sUA) and high-sensitivity C-reactive protein (hsCRP) were measured in the gout group, and correlated with FMD and NMD responses. Both FMD (2.20 ± 0.53 vs 3.56 ± 0.31, p = 0.021) and NMD (16.69 ± 1.54 vs 24.51 ± 0.90, p = 0.00002) were impaired in the gout versus control group. Stratification for individual comorbidities suggested that no single risk factor accounted for impaired FMD/NMD in the gout subjects. However, the degree of association between gout and FMD, but not NMD impairment, was dampened after multivariable adjustment (FMD unadjusted beta = - 1.36 (SE 0.58), p = 0.02; adjusted beta = - 1.16 (SE 0.78), p = 0.14 and NMD unadjusted beta = - 7.68 (SE 1.78), p < 0.0001; adjusted beta = - 5.33 (SE 2.46), p = 0.03). Within the gout group, there was an inverse correlation between FMD and sUA (R = - 0.5, p = 0.003), and between FMD and hsCRP (R = - 0.42, p = 0.017), but not between NMD and sUA or hsCRP. Compared with healthy controls, subjects with gout have reduced arterial function. Individual comorbidities are insufficient to account for differences between gout and control groups, but multiple comorbidities may collectively contribute to impairment in endothelium-dependent arterial responsiveness. Endothelial impairment is also related to sUA and hsCRP, markers of gout severity and inflammation respectively. Studies to determine whether gout therapy may improve arterial responsiveness are warranted.

Arterial function, biomarkers, carcinoid syndrome and carcinoid heart disease in patients with small intestinal neuroendocrine tumours

PURPOSE

Carcinoid heart disease (CHD) is a life-threatening complication of carcinoid syndrome (CS) characterised by tricuspid regurgitation (TR). However, there is an unmet need for earlier diagnosis of CHD. We cross-sectionally assessed the prevalence and potential predictive or diagnostic markers for CS and CHD in a contemporary cohort of patients with small intestinal neuroendocrine tumours (SI-NETs).

METHODS

Biochemical characteristics, hepatic tumour load, measures of arterial and endothelial function, atherosclerosis, and transthoracic echocardiography were analysed in a prospective cross-sectional setting.

RESULTS

Among the 65 patients studied, 29 (45%) had CS (CS+ ), and 3 (5%) CHD. CS+ was characterised by significantly higher hepatic tumour load, S-5-HIAA and fP-CgA, higher frequency of diarrhoea and flushing, and more frequent PRRT compared to CS- (for all, P < 0.05). Central systolic, central mean, and central end-systolic blood pressures were significantly higher in CS+ than in CS- (for all, P < 0.05). Subjects with grades 2-4 TR had higher hepatic tumour burden, fP-CgA, and S-5-HIAA compared to those with grades 0-1 TR, but measures of vascular function did not differ. fP-CgA (P = 0.017) and S-5-HIAA (P = 0.019) but not proBNP increased significantly according to the severity of TR.

CONCLUSION

Although CS is common, the prevalence of CHD was found to be lower in a contemporary cohort of SI-NET patients than previously anticipated. Measures of arterial or endothelial function or carotid atherosclerosis do not identify subjects with mild TR. Echocardiography remains the most sensitive means to diagnose CHD in CS patients with high tumour burden and elevated CgA and 5-HIAA.

Relationship between cardio-ankle vascular index and homocysteine in hypertension subjects with hyperhomocysteinemia

BACKGROUND

Arteriosclerosis evaluated by arterial stiffness is the basic pathophysiological change during the development of hypertension. Cardio-ankle vascular index (CAVI) is an index of arterial stiffness. Hyperhomocysteinemia (HHcy) is an independent risk factor for vascular diseases. However, there was little research about the relationship between CAVI and homocysteine (Hcy) in hypertension subjects with HHcy.

METHODS

A total of 330 subjects (M/F 133/197) from Vascular Medicine of Peking University Shougang Hospital were divided into four groups: control group (group 1, normotensive with normal Hcy, n = 149), hypertension group (group 2, n = 113), HHcy group (group 3, n = 30), and hypertension with HHcy group (group 4, n = 38). CAVI was measured by VS-1000 apparatus.

RESULTS

Our results showed that CAVI was significantly higher in group 4 than in group 1 and group 2 (8.41 ± 1.08 vs. 7.79 ± 1.14; 8.41 ± 1.08 vs. 7.87 ± 1.02, both p < 0.05, respectively). Positive correlation between CAVI and Hcy was found in the entire study group (r = 0.109, p = 0.049) and hypertension subjects (group 2 + group 4; r = 0.202, p = 0.014). Multivariate analysis showed that Hcy was an independent associating factor of CAVI in all subjects (β = 0.251, p = 0.034).

CONCLUSIONS

The present study showed that CAVI was significantly higher in hypertension subjects with HHcy compared to hypertension group. There was significant correlation between CAVI and Hcy, indicating the relationship between arterial stiffness and biomarkers in vascular-related diseases.

Towards the non-invasive determination of arterial wall distensible properties: New approach using old formulae

Arterial function and wall mechanical properties are important determinants of hemodynamics in the circulation. However, their non-invasive determination is not widely available. Therefore, the aim of this work is to present a novel approach for the non-invasive determination of vessel's distensibility and elastic modulus. Simultaneous measurements of vessel's Diameter (D) and flow velocity (U) were recorded to determine local wave speed (_nC) in flexible tubes and calf aortas non-invasively using the lnDU-loop method, which was used to calculate the Distensibility (_nD_s) and Elastic Modulus (_nE), also non-invasively. To validate the new approach, the non-invasive results were compared to traditionally invasive measurements of Dynamic Distensibility (D_sd) and Tangential Elastic Modulus (E_m). In flexible tubes, the average _nD_s was higher and _nE was lower than D_sd and E_m by 1.6% and 6.9%, respectively. In calf aortas, the results of _nD_s and _nE agreed well with those of D_sd and E_m, as demonstrated by Bland-Altman technique. The results of _nD_s and _nE are comparable to those determined using traditional techniques. Our results suggest that _nD_s and _nE could be measured in-vivo non-invasively, given the possibility of measuring D and U to obtain _nC. Further studies are warranted to establish the clinical usefulness of the new approach.

Maternal Serum B Cell activating factor in hypertensive and normotensive pregnancies

OBJECTIVES

The objective of this study was the analysis of B-Cell Activating Factor (BAFF) levels in pregnancies affected by PE, and in pregnancies affected by fetal growth restriction without Hypertensive disorders and its possible correlation with pulse wave velocity and cardiac output.

STUDY DESIGN

Prospective study of 69 women at 24-40 weeks gestation. Haemodynamic function was assessed in those with Pre-eclampsia (PE, n = 19), fetal growth restriction (FGR, n = 10) and healthy pregnancies (n = 40). Maternal venous BAFF levels at recruitment were measured using ELISA. We analysed the relationship between BAFF and cardiac output (CO), and BAFF and PWV (pulse wave velocity); the gold standard for assessing arterial stiffness. PWV was measured with an oscillometric device and CO using inert gas rebreathing technique. PWV and CO were converted to gestation adjusted indices (z scores).

MAIN OUTCOME MEASURES

The association between BAFF levels in PE and FGR, and the relationship of BAFF with PWV and CO.

RESULTS

BAFF was higher in PE (p = 0.03) but not in FGR (p = 0.83) when compared to healthy pregnancies. There was a positive correlation between BAFF levels and z score PWV (r = 0.25, p = 0.04), but not CO (r = -0.01, p = 0.91). BAFF levels did not change with gestational age. (r = 0.012, p = 0.925).

CONCLUSIONS

These findings provide evidence of a possible contribution of BAFF to both maternal inflammation and arterial dysfunction associated with PE. Though no relationship was found with another disorder of placentation: normotensive FGR, this condition is not thought to be associated with maternal inflammation.

T-Wave Indices and Atherosclerosis

Tpeak-Tend interval, the time difference between the peak and the end of the T-wave, reflects the degree of dispersion of repolarization. Its prolongation has been associated with higher risks of developing ventricular arrhythmias and sudden cardiac death in different pro-arrhythmic conditions such as Brugada and long QT syndromes. In this review, we will provide a comprehensive overview on how Tpeak-Tend is altered in different atherosclerotic conditions such as hypertension, stable coronary artery disease, acute coronary obstruction, and coronary slow flow as well as inflammatory diseases affecting the arterial tree. We will explore its relationship with arterial function and dysfunction, ventricular remodeling, and arrhythmic and mortality outcomes. The published literature shows that patients with coronary atherosclerosis, whether in the form of stable coronary artery disease, chronic total occlusion, slow flow, or acute coronary obstruction, have prolonged Tpeak-Tend intervals and Tpeak-Tend/QT ratios. These can be used to predict the occurrence of ventricular arrhythmias and sudden cardiac death. They also correlate with the extent and severity of arterial stenosis and structural remodeling of the ventricles as well as arterial function and dysfunction. Finally, they can be normalized following revascularization and may therefore be used as a surrogate measure of treatment success.

Uterine kallikrein and arterial bradykinin activities and uterine arterial proliferation in response to acute estradiol-17β exposure in ovariectomized ewes

Estradiol-17β (E2) increases kallikrein in rodent and human reproductive tissues. Kallikrein specific activity is increased in the porcine uterus when conceptus E2 is secreted at maternal recognition of pregnancy. When kallikrein acts on kininogen to liberate bradykinin, angiogenic and vasoactive factors are released. The uterus of ovariectomized ewes administered E2 undergoes rapid vascular changes via different patterns of angiogenic and vasoactive factors. Our hypothesis was that E2 would increase the specific activity and protein secretion of tissue kallikrein in endometrial explants culture media (ECM) and ewes exposed to E2 would have uterine arteries that would be more sensitive to the vasodilatory effects of bradykinin. Ovariectomized ewes received 100 mg of E2 implants for 0, 12, 24, or 48 h. After treatment, uterine weights were determined, and caruncles were processed for ECM. Uterine weights and uterine weight per ewe body weight were significantly greater in the 12 and 24 h ewes compared with the 0 h ewes, with the 48 h ewes being similar to the 24 h ewes. There were no statistically significant differences in caruncular tissue kallikrein protein secretion among the treatment groups. There was a tendency (P = 0.09) for duration of E2 exposure to influence tissue kallikrein specific activity where kallikrein activity was greater (P ≤ 0.05) in the 12 and 48 h ewes compared with the 0 h ewes, with 24 h ewes being intermediate (unprotected F test). Uterine arteries from ewes with E2 for 24 and 48 h had more sensitivity to bradykinin, via the bradykinin receptor 2, than uterine arteries from ewes with 0 or 12 h E2 exposure. We fail to reject our hypothesis as E2 did elicit a positive response in tissue kallikrein specific activity and bradykinin response. Further investigations are needed to determine how kallikrein and bradykinin may be involved in vascular remodeling of the ovine uterus.

Glycocalyx-targeted therapy ameliorates age-related arterial dysfunction

Advanced age is accompanied by arterial dysfunction, as well as a diminished glycocalyx, which may be linked to reduced high molecular weight-hyaluronan (HMW-HA) synthesis. However, the impact of glycocalyx deterioration in age-related arterial dysfunction is unknown. We sought to determine if manipulations in glycocalyx properties would alter arterial function. Tamoxifen-induced hyaluronan synthase 2 (Has2) reduction was used to decrease glycocalyx properties. Three weeks post-tamoxifen treatment, glycocalyx thickness was lower in Has2 knockout compared to wild-type mice (P<0.05). Has2 reduction induced arterial dysfunction, demonstrated by impaired endothelium-dependent dilation (EDD) and elevated aortic stiffness (P<0.05). To augment glycocalyx properties, old mice received 10 weeks of a glycocalyx-targeted therapy via Endocalyx™ (old+ECX), which contains HMW-HA and other glycocalyx components. Compared to old control mice, glycocalyx properties and EDD were augmented, and aortic stiffness decreased in old+ECX mice (P<0.05). Old+ECX mice had a more youthful aortic phenotype, demonstrated by lower collagen content and higher elastin content than old control mice (P<0.05). Functional outcomes were repeated in old mice that underwent a diet supplemented solely with HMW-HA (old+HA). Compared to old controls, glycocalyx properties and EDD were augmented, and aortic stiffness was lower in old+HA mice (P<0.05). We did not observe any differences between old+HA and old+ECX mice (P>0.05). Has2 reduction phenocopies age-related arterial dysfunction, while 10 weeks of glycocalyx-targeted therapy that restores the glycocalyx also ameliorates age-related arterial dysfunction. These findings suggest that the glycocalyx may be a viable therapeutic target to ameliorate age-related arterial dysfunction.