Characteristics of pulse wave velocity in elastic and muscular arteries: a mismatch beyond age. J Hypertens. 2013;31:554-559; discussion 559. [PMID: 23615212 DOI: 10.1097/hjh.0b013e32835d4aec]

Aortic-Femoral Stiffness Gradient and Cardiovascular Risk in Older Adults

BACKGROUND

The aortic-femoral arterial stiffness gradient, calculated as the ratio of lower-limb pulse-wave velocity (PWV) to central (aortic) PWV, is a promising tool for assessing cardiovascular disease (CVD) risk, but whether it predicts incident CVD is unknown.

METHODS

We examined the association of the aortic-femoral arterial stiffness gradient measures carotid-femoral stiffness gradient (femoral-ankle PWV divided by carotid-femoral PWV) and the heart-femoral stiffness gradient (femoral-ankle PWV divided by heart-femoral PWV), as well as PWV, with incident CVD (coronary disease, stroke, and heart failure) and all-cause mortality among 3109 participants of the Atherosclerosis Risk in Communities Study cohort (age, 75±5 years; carotid-femoral PWV, 11.5±3.0 m/s), free of CVD. Cox regression was used to estimate hazard ratios (HR) and 95% CIs.

RESULTS

Over a median 7.4-year follow-up, there were 322 cases of incident CVD and 410 deaths. In fully adjusted models, only top quartiles of carotid-femoral stiffness gradient (quartile 4: HR, 1.43 [95% CI, 1.03-1.97]; and quartile 3: HR, 1.49 [95% CI, 1.08-2.05]) and heart-femoral stiffness gradient (quartile 4: HR, 1.77 [95% CI, 1.27-2.48]; and quartile 3: HR, 1.41 [95% CI, 1.00-2.00]) were significantly associated with a greater risk of incident CVD. Only high aortic stiffness in combination with low lower-limb stiffness was significantly associated with incident CVD (HR, 1.46 [95% CI, 1.06-2.02]) compared with the referent low aortic stiffness and high lower-limb stiffness. No PWVs were significantly associated with incident CVD. No exposures were associated with all-cause mortality.

CONCLUSIONS

The aortic-femoral arterial stiffness gradient may enhance CVD risk assessment in older adults in whom the predictive capacity of traditional risk factors and PWV are attenuated.

Long-term effects of COVID-19 on endothelial function, arterial stiffness, and blood pressure in college students: a pre-post-controlled study

BACKGROUND

The COVID-19 has been shown to have negative effects on the cardiovascular system, but it is unclear how long these effects last in college students. This study aimed to assess the long-term impact of COVID-19 on arterial stiffness, endothelial function, and blood pressure in college students.

METHODS

We enrolled 37 college students who had been infected with COVID-19 for more than 2 months. Brachial artery flow-mediated dilation (FMD) was used to assess endothelial function, while arterial stiffness was evaluated using the ABI Systems 100, including variables such as ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), carotid-femoral pulse wave velocity (cfPWV), heart rate (HR), and blood pressure (BP).

RESULTS

Our results showed that FMD was significantly impaired after COVID-19 infection (p < 0.001), while cfPWV and systolic blood pressure (SBP) were significantly increased (p < 0.05). Simple linear regression models revealed a significant negative correlation between post-COVID-19 measurement time and baPWV change (p < 0.01), indicating an improvement in arterial stiffness over time. However, there was a significant positive correlation between post-COVID-19 measurement time and diastolic blood pressure (DBP) change (p < 0.05), suggesting an increase in BP over time. There were no significant differences in ABI and HR between pre- and post-COVID-19 measurements, and no significant correlations were observed with other variables (p > 0.05).

CONCLUSION

Our study demonstrated that COVID-19 has long-term detrimental effects on vascular function in college students. However, arterial stiffness tends to improve over time, while BP may exhibit the opposite trend.

Anatomical location, sex, and age modulate adipocyte progenitor populations in perivascular adipose tissues

Perivascular adipose tissue (PVAT) regulates vascular function due to its capacity to synthesize vasoactive products and its mechanical properties. PVATs most abundant cells are adipocytes, and their populations are maintained by the maturation of adipocyte progenitor cells (APC), which may play a pivotal role in the pathogenesis of cardiovascular diseases. However, the distribution of APC within PVAT depots, their potential variation in spatial location, and the influence of sex and age on their abundance remain unknown. We hypothesize that APC abundance in PVAT is affected by location, age, sex and that APC subtypes have specific spatial distributions. PVAT from thoracic and abdominal aorta, and mesenteric arteries, and AT from interscapular, gonadal, and subcutaneous depots from 13-week and 30-week-old females and males Pdgfrα-CreERT2 x LSL-tdTomato mice (n = 28) were analyzed. Abdominal aorta PVAT had fewer progenitors than mesenteric PVAT and gonadal AT. Aging reduced the abundance of APC in the thoracic aorta but increased their numbers in mesenteric PVAT. Females had more APC than males in mesenteric PVAT and gonadal AT depots. APC exhibited unique spatial distribution in the aorta and mesenteric PVAT where they localized neighboring vasa vasorum and arteries. APC subtypes (APC1, APC2, APC3, diff APC) were identified in all PVAT depots. Thoracic aorta PVAT APC3 were located in the adventitia while diff APC were in the parenchyma. This study identified variability in APC populations based on depot, age, and sex. The distinctive spatial distribution and the presence of diverse APC subtypes suggest that they may contribute differently to cardiovascular diseases-induced PVAT remodeling.

Structural and Mechanical Properties of Human Superficial Femoral and Popliteal Arteries

The femoropopliteal artery (FPA) is the main artery in the lower limb. It supplies blood to the leg muscles and undergoes complex deformations during limb flexion. Atherosclerotic disease of the FPA (peripheral arterial disease, PAD) is a major public health burden, and despite advances in surgical and interventional therapies, the clinical outcomes of PAD repairs continue to be suboptimal, particularly in challenging calcified lesions and biomechanically active locations. A better understanding of human FPA mechanical and structural characteristics in relation to age, risk factors, and the severity of vascular disease can help develop more effective and longer-lasting treatments through computational modeling and device optimization. This review aims to summarize recent research on the main biomechanical and structural properties of human superficial femoral and popliteal arteries that comprise the FPA and describe their anatomy, composition, and mechanical behavior under different conditions.

Calcium signaling in endothelial and vascular smooth muscle cells: sex differences and the influence of estrogens and androgens

Calcium signaling in vascular endothelial cells (ECs) and smooth muscle cells (VSMCs) is essential for the regulation of vascular tone. However, the changes to intracellular Ca2+ concentrations are often influenced by sex differences. Furthermore, a large body of evidence shows that sex hormone imbalance leads to dysregulation of Ca2+ signaling and this is a key factor in the pathogenesis of cardiovascular diseases. In this review, the effects of estrogens and androgens on vascular calcium-handling proteins are discussed, with emphasis on the associated genomic or nongenomic molecular mechanisms. The experimental models from which data were collected were also considered. The review highlights 1) in female ECs, transient receptor potential vanilloid 4 (TRPV4) and mitochondrial Ca2+ uniporter (MCU) enhance Ca2+-dependent nitric oxide (NO) generation. In males, only transient receptor potential canonical 3 (TRPC3) plays a fundamental role in this effect. 2) Female VSMCs have lower cytosolic Ca2+ levels than males due to differences in the activity and expression of stromal interaction molecule 1 (STIM1), calcium release-activated calcium modulator 1 (Orai1), calcium voltage-gated channel subunit-α1C (CaV1.2), Na+-K+-2Cl- symporter (NKCC1), and the Na+/K+-ATPase. 3) When compared with androgens, the influence of estrogens on Ca2+ homeostasis, vascular tone, and incidence of vascular disease is better documented. 4) Many studies use supraphysiological concentrations of sex hormones, which may limit the physiological relevance of outcomes. 5) Sex-dependent differences in Ca2+ signaling mean both sexes ought to be included in experimental design.

Association of carotid wall shear stress measured by vector flow mapping technique with ba-PWV: a pilot study

Objective

Arterial stiffness is an important tissue biomarker of the progression of atherosclerotic diseases. Brachial-ankle pulse wave velocity (ba-PWV) is a gold standard of arterial stiffness measurement widely used in Asia. Changes in vascular wall shear stress (WSS) lead to artery wall remodeling, which could give rise to an increase in arterial stiffness. The study aimed to explore the association between ba-PWV and common carotid artery (CCA) WSS measured by a newly invented vascular vector flow mapping (VFM) technique.

Methods

We included 94 subjects free of apparent cardiovascular disease (CVD) and divided them into a subclinical atherosclerosis (SA) group (N = 47) and non subclinical atherosclerosis (NSA) group (N = 47). CCA WSS was measured using the VFM technique. Bivariate correlations between CCA WSS and other factors were assessed with Pearson's, Spearman's, or Kendall's coefficient of correlation, as appropriate. Partial correlation analysis was conducted to examine the influence of age and sex. Multiple linear stepwise regression was used for the analysis of independent determinants of CCA WSS. Receiver operating characteristic (ROC) analysis was performed to find the association between CCA WSS and 10-year CVD risk.

Results

The overall subjects had a mean age of 47.9 ± 11.2 years, and males accounted for 52.1%. Average systolic CCA WSS was significantly correlated with ba-PWV (r = -0.618, p < 0.001) in the SA group. Multiple linear stepwise regression analysis confirmed that ba-PWV was an independent determinant of average systolic CCA WSS (β = -0.361, p = 0.003). The area under the curve (AUC) of average systolic CCA WSS for 10-year CVD risk ≥10% was 0.848 (p < 0.001) in the SA group.

Conclusions

Average systolic CCA WSS was significantly correlated with ba-PWV and was associated with 10-year CVD risk ≥10% in the SA group. Therefore, CCA WSS measured by the VFM technique could be used for monitoring and screening subjects with potential CVD risks.

Assessment of aortic to peripheral vascular stiffness and gradient by segmented upper limb PWV in healthy and hypertensive individuals

Theoretically pulse wave velocity (PWV) is obtained by calculating the distance between two waveform probes divided by the time difference, and PWV ratio is used to assess the arterial stiffness gradient (SG) from proximal to distal. The aim was to investigate segmental upper-limb PWV (ulPWV) differences and the effects of hypertension and or aging on each ulPWV and SG. The study collected multi-waveform signals and conduction distances from 167 healthy individuals and 92 hypertensive patients. The results showed significant differences between ulPWVs (P < 0.001), with increased and then decreased vascular stiffness along the proximal transmission to the distal peripheral artery and then to the finger. Adjusted for age and sex, ulPWVs in hypertension exceeded that of healthy individuals, with significant differences between groups aged ≥ 50 years (P < 0.05). The hrPWV/rfPWV (heart-radial/radial-finger) was reduced in hypertension and differed significantly between the aged ≥ 50 years (P = 0.015); the ratio of baPWV (brachial-ankle) to ulPWV differed significantly between groups (P < 0.05). Hypertension affected the consistency of rfPWV with hfPWV (heart-finger). The findings suggest that segmented ulPWV is instrumental in providing stiffness corresponding to the physiological structure of the vessel. The superimposition of hypertension and or aging exacerbates peripheral arterial stiffness, as well as alteration in stiffness gradient.

Use of phase-contrast MRI to measure aortic stiffness in young-onset hypertension: a pilot study

BACKGROUND

Young-onset hypertension is defined as hypertension diagnosed before the age of 40 years. Aortic pulse wave velocity is an indication of aortic stiffness. MRI assessment has been well verified compared to invasive pressure recordings for evaluating aortic pulse wave velocity. In this study, we aimed to determine whether aortic stiffness played a role in the aetiology of young-onset hypertension by calculating pulse wave velocity using MRI.

METHODS

We enrolled 20 patients diagnosed with young-onset hypertension and 20 volunteers without hypertension. Aortic pulse wave velocity was measured by cardiac MRI and protocol for the pulse wave velocity measurement involved the use of a 1.5 T scanner to acquire velocity-encoded, phase-contrast transverse aortic cine images. Sagittal oblique images used to measure the distance (ΔX) between the ascending aorta and descending aorta for the calculation of pulse wave velocity. The aortic flow versus time curves of ascending aorta and descending aorta were automatically obtained from the phase-contrast MRI images. Using these curves, the temporal shift (ΔT) was measured by Segment Medviso.

FINDINGS

The mean pulse wave velocity was 8.72 (SD 2.34) m/second (range: 7-12.8 m/second) for the patient group and 5.96 (standard deviation 1.86) m/second (range: 4.8-7.1 m/second) for the control group. The pulse wave velocity values were significantly higher in the patient group compared to the control group (p < 0.001).

INTERPRETATION

Aortic stiffness may play a role in the aetiology of young-onset hypertension and serve as a non-invasive and reliable screening tool when measured by MRI.

Vascular stiffening and endothelial dysfunction in atherosclerosis

PURPOSE OF REVIEW

Aging is an important risk factor for cardiovascular disease and is associated with increased vessel wall stiffness. Pathophysiological stiffening, notably in arteries, disturbs the integrity of the vascular endothelium and promotes permeability and transmigration of immune cells, thereby driving the development of atherosclerosis and related vascular diseases. Effective therapeutic strategies for arterial stiffening are still lacking.

RECENT FINDINGS

Here, we overview the literature on age-related arterial stiffening, from patient-derived data to preclinical in-vivo and in-vitro findings. First, we overview the common techniques that are used to measure stiffness and discuss the observed stiffness values in atherosclerosis and aging. Next, the endothelial response to stiffening and possibilities to attenuate this response are discussed.

SUMMARY

Future research that will define the endothelial contribution to stiffness-related cardiovascular disease may provide new targets for intervention to restore endothelial function in atherosclerosis and complement the use of currently applied lipid-lowering, antihypertensive, and anti-inflammatory drugs.

Comparison of carotid-femoral and brachial-ankle pulse wave velocity in association with carotid plaque in a Chinese community-based population

Pulse wave velocity (PWV) is the most widely used measurement of arterial stiffness in clinical practice. This study aimed to evaluate and compare the relationships between carotid-femoral pulse wave velocity (cfPWV) and brachial-ankle PWV (baPWV) and the presence of carotid plaque. This study was designed cross-sectionally and included 6027 participants from a community-based cohort in Beijing. Logistic regression analyses were performed to evaluate and compare the associations of cfPWV and baPWV with the presence of carotid plaque. The mean (SD) cfPWV and baPWV were 8.55 ± 1.83 and 16.79 ± 3.36, respectively. The prevalence of carotid plaque was 45.26% (n = 2728). Both cfPWV (per 1 m/s increase: OR = 1.11, 95% CI: 1.07-1.16) and baPWV (OR = 1.04, 95% CI: 1.02-1.06) were independently associated with carotid plaque after adjusting for various confounders. Compared with bottom quartile (cfPWV ≤7.31 m/s and baPWV ≤14.44 m/s), the top quartile of cfPWV and baPWV had a significantly higher prevalence of carotid plaque (for cfPWV: OR = 1.59, 95% CI: 1.32-1.92; for baPWV: OR = 1.53, 95% CI: 1.26-1.86). However, the relationship of baPWV and carotid plaque was nonlinear, with a positive trend only when baPWV < 16.85 m/s. When comparing relationships between PWV indices and carotid plaque in one model, both cfPWV and baPWV were significantly associated with carotid plaque in participants with baPWV < 16.85 m/s; however, only cfPWV was independently associated with carotid plaque in participants with baPWV ≥16.85 m/s. Both cfPWV and baPWV were significantly associated with carotid plaque in the Chinese community-based population. Furthermore, cfPWV was more strongly correlated with carotid plaque than baPWV in participants with baseline baPWV ≥16.85 m/s.

An XGBoost-based model for assessment of aortic stiffness from wrist photoplethysmogram

BACKGROUND AND OBJECTIVE

Carotid-femoral pulse wave velocity (cf-PWV) is the gold standard for non-invasive assessment of aortic stiffness. Photoplethysmography used in wearable devices provides an indirect measurement method for cf-PWV. This study aimed to construct a cf-PWV prediction method based on the XGBoost algorithm and wrist photoplethysmogram (wPPG) for the early screening of arteriosclerosis in primary healthcare.

METHODS

Data from 210 subjects were used for modeling, and 100 subjects were used as an external validation set. The wPPG pulse waves were filtered by discrete wavelet transform, and various features were extracted from each waveform, including two original indexes. The extraction rate (ER) and Pearson P were calculated to evaluate the applicability of each feature for model training. The magnitude of cf-PWV was predicted by an XGBoost-based model using the selected features and basic physiological parameters (age, sex, height, weight and BMI). The level of aortic stiffness was classified by a 3-classification strategy according to the standard cf-PWV (measured by the Complior device). Bland-Altman plot, Pearson correlation analysis, and accuracy tested performance from two aspects: predicting the magnitude of cf-PWV and classifying the level of aortic stiffness.

RESULTS

In the external validation set (n = 100, age range 22-79), 97 subjects obtained features (ER = 97%). The predicted cf-PWV was significantly correlated with the standard cf-PWV (r = 0.927, P < 0.001). The accuracy (AC) of the 3-classification was 85.6%. The interrater agreement for assessing aortic stiffness was at least substantial (quadratically weighted Kappa = 0.833).

CONCLUSIONS

The multi-parameter fusion cf-PWV prediction method based on the XGBoost algorithm and wPPG pulse wave analysis proves the feasibility of atherosclerosis screening in wearable devices.

Inadequacy of Augmentation Index for Monitoring Arterial Stiffness: Comparison with Arterial Compliance and Other Hemodynamic Variables

PURPOSE

Augmentation Index (AI_x) is used clinically for monitoring both wave reflections and arterial stiffness, which when increased is a risk factor of cardiovascular mortality and morbidity. We hypothesize that AI_x is not solely related to vascular stiffness as described by arterial compliance and other hemodynamic parameters since AI_x underestimates wave reflections.

METHODS

Aortic pressure and flow datasets (n = 42) from mongrel dogs were obtained from our experiments and Mendeley Data under various conditions. Arterial compliances based on the Windkessel model (C_t), the stroke volume (SV) to pulse pressure (PP) ratio (C_v = SV/PP), and at inflection pressure point (C_Pi) were computed. Other relevant hemodynamic factors are also computed.

RESULTS

AI_x was poorly associated with arterial stiffness calculated from C_t (r = 0.299, p = 0.058) or C_Pi (r = 0.203, p = 0.203), even when adjusted for heart rates. C_t and C_v were monotonically associated. Alterations in inflection pressure (P_i) did not follow the changes in pulse pressure (PP) (r = 0.475, p = 0.002), and P_i was quantitatively similar to systolic pressure (r = 0.940, p < 0.001).

CONCLUSION

AI_x is neither linearly correlated with arterial stiffness, nor with arterial compliance and several cardiac and arterial parameters have to be considered when AI_x is calculated.

Association between measurements of arterial stiffness and target organ damage in a general Spanish population

INTRODUCTION

Little is known about the relationship between arterial stiffness and cardiovascular target organ damage (TOD) in the general population. The aim was to analyse the relationship between different measurements of arterial stiffness and TOD, in a general Spanish population without a history of cardiovascular event.

MATERIALS AND METHODS

Transversal descriptive study. Through stratified random sampling, a total of 501 individuals were included. Carotid-femoral pulse wave velocity (cf-PWV) was measured using a SphygmoCor System®, the cardio-ankle vascular index (CAVI) was determined with aVasera VS-1500® and brachial-ankle pulse wave velocity (ba-PWV)was calculated through a validated equation.

RESULTS

The average age was 55.84 ± 14.26.The percentage of vascular TOD, left ventricular hypertrophy (LVH) and renal TOD was higher in men (p < .001). A positive correlation was obtained between carotid intima-media thickness (c-IMT) and the measurements of vascular function. In the model 1 of the logistic regression analysis, cf-PWV was associated with vascular TOD (OR = 1.15, p = .040), ba-PWV was associated with vascular TOD (OR = 1.20, p = .010) and LVH (OR = 1.12, p = .047).

CONCLUSIONS

The different measurements of arterial stiffness are highly associated with each other. Moreover, cf-PWV and ba-PWV were associated with vascular TOD, and ba-PWV with LVH, although they disappear when adjusting for cardiovascular risk factors. Key Messages There is a strong correlation between the different measurements of vascular structure and function. Carotid-femoral and brachial-ankle pulse wave velocity were positively associated with vascular target organ damage, the latter was also positively associated with left ventricular hypertrophy. This associations disappear when adjusting for cardiovascular risk factors.

Comparing oscillometric and tonometric methods to assess pulse wave velocity: a population-based study

BACKGROUND

Oscillometric pulse wave velocity (o-PWV) represents an attractive, non invasive and non operator-dependent method to estimate arterial stiffness. Tonometric carotid-femoral measurements (cf-PWV),are considered the gold-standard for non-invasive aortic stiffness assessment. To date, no studies in the general population comparing the two methods have been performed.

METHODS AND RESULTS

1162 subjects were analysed. O-PWV and cf-PWV showed a mean difference of -0.31 m/sec(p ≤ 0.001). No significant differences between cf-PWV and o-PWVs were observed in patients without cardiovascular risk factors. The Bland and Altman analysis showed a moderate agreement between 24 h-o-PWV and cf-PWV (mean difference -0.99, LoA 4.23 to -6.22m/s). O-PWVs underestimate and overestimate arterial stiffness under and over 50 years respectively(p ≤ 0.001). Systolic blood pressure (SBP) and age differently impact cf-PWV and in office o-PWV variability (r2 0.35 and 0.88 respectively). In younger subjects a strong relationship between o-PWV and SBP reducing as age increases was found. Analysing the impact of age, an opposite trend was noticed.

CONCLUSIONS

Oscillometric PWV estimates provide reliable values in the general population. An o-PWV tendency to underestimate arterial stiffness in younger subjects and in subjects with diseases known to increase arterial stiffness and to overestimate it with increasing age was found, even if scarcely relevant in clinical perspective. Overall the present findings underline an acceptable and satisfactory agreement between oscillometric and tonometric methods for the PWV assessment. KEY MESSAGES Oscillometric and tonometric PWV estimates showed a good and satisfactory agreement in the general population, above all in subjects without cardiovascular risk factors or a documented vascular damage. In comparison with tonometric values, oscillometric PWV estimates showed, however, the tendency to underestimate arterial stiffness in younger subjects and to overestimate it with increasing age, while diverging when diseases known to increase arterial stiffness are present. The magnitude of differences in PWV estimates between tonometric and oscillometric methods found in the general population appears most likely not to be significant in everyday clinical practice.

Arterial Stiffness in Renal Transplant Recipients: 5-Year Follow-up

BACKGROUND

Chronic kidney disease is a risk factor for cardiovascular diseases. After renal transplant, some traditional and chronic kidney disease-specific risk factors vanish, but new risk factors emerge. This retrospective study aimed to define the long-term impact of renal transplant and diabetes mellitus on arterial stiffness, evaluated by measuring pulse wave velocity (PWV) and augmentation index (AI) and on myocardial perfusion, evaluated by subendocardial viability ratio (SEVR).

METHODS

PWV, AI, and SEVR were evaluated noninvasively by applanation tonometry using SphygmoCor in the first 4 weeks after kidney transplant and 4 to 5 years thereafter.

RESULTS

A total of 48 graft recipients (18 women, 30 men; mean ± standard deviation age, 47.9 ± 11.8 years) were included. The follow-up period was 57.4 ± 8.0 months. PWV did not change significantly during the follow-up period (9.1 ± 1.8m/s and 8.7 ± 1.8m/s, respectively; P = .137). In the subgroup of patients without diabetes mellitus, we observed a trend of PWV reduction, whereas in the subgroup of patients with diabetes we observed the trend of PWV increase. The duration of smoking before transplant correlated significantly with PWV (P = .012). AI in the whole group increased significantly during the study period (from 18.3% ±10.3% to 25.9% ±9.4%; P < .01) as well as SEVR (from 134.9 ± 23.1 to 155.4 ± 28.6; P = .001).

CONCLUSIONS

PWV, reflecting the central vessel stiffness, did not change significantly in the whole group during the follow-up period. The AI, which indicates systemic stiffness, increased significantly within 5 years after transplant, indicating the progression of vascular processes of elastic and muscular arteries. Significant increases in the SEVR values in both diabetics and nondiabetics indicate the long-term favorable effect of kidney transplant on myocardial perfusion.

Comparison of morphometric, structural, mechanical, and physiologic characteristics of human superficial femoral and popliteal arteries

Peripheral arterial disease differentially affects the superficial femoral (SFA) and the popliteal (PA) arteries, but their morphometric, structural, mechanical, and physiologic differences are poorly understood. SFAs and PAs from 125 human subjects (age 13-92, average 52±17 years) were compared in terms of radii, wall thickness, and opening angles. Structure and vascular disease were quantified using histology, mechanical properties were determined with planar biaxial extension, and constitutive modeling was used to calculate the physiologic stress-stretch state, elastic energy, and the circumferential physiologic stiffness. SFAs had larger radii than PAs, and both segments widened with age. Young SFAs were 5% thicker, but in old subjects the PAs were thicker. Circumferential (SFA: 96→193°, PA: 105→139°) and longitudinal (SFA: 139→306°, PA: 133→320°) opening angles increased with age in both segments. PAs were more diseased than SFAs and had 11% thicker intima. With age, intimal thickness increased 8.5-fold, but medial thickness remained unchanged (620μm) in both arteries. SFAs had 30% more elastin than the PAs, and its density decreased ~50% with age. SFAs were more compliant than PAs circumferentially, but there was no difference longitudinally. Physiologic circumferential stress and stiffness were 21% and 11% higher in the SFA than in the PA across all ages. The stored elastic energy decreased with age (SFA: 1.4→0.4kPa, PA: 2.5→0.3kPa). While the SFA and PA demonstrate appreciable differences, most of them are due to vascular disease. When pathology is the same, so are the mechanical properties, but not the physiologic characteristics that remain distinct due to geometrical differences.

Mechanical, structural, and physiologic differences in human elastic and muscular arteries of different ages: Comparison of the descending thoracic aorta to the superficial femoral artery

Elastic and muscular arteries differ in structure, function, and mechanical properties, and may adapt differently to aging. We compared the descending thoracic aortas (TA) and the superficial femoral arteries (SFA) of 27 tissue donors (average 41±18 years, range 13-73 years) using planar biaxial testing, constitutive modeling, and bidirectional histology. Both TAs and SFAs increased in size with age, with the outer radius increasing more than the inner radius, but the TAs thickened 6-fold and widened 3-fold faster than the SFAs. The circumferential opening angle did not change in the TA, but increased 2.4-fold in the SFA. Young TAs were relatively isotropic, but the anisotropy increased with age due to longitudinal stiffening. SFAs were 51% more compliant longitudinally irrespective of age. Older TAs and SFAs were stiffer, but the SFA stiffened 5.6-fold faster circumferentially than the TA. Physiologic stresses decreased with age in both arteries, with greater changes occurring longitudinally. TAs had larger circumferential, but smaller longitudinal stresses than the SFAs, larger cardiac cycle stretch, 36% lower circumferential stiffness, and 8-fold more elastic energy available for pulsation. TAs contained elastin sheets separated by smooth muscle cells (SMCs), collagen, and glycosaminoglycans, while the SFAs had SMCs, collagen, and longitudinal elastic fibers. With age, densities of elastin and SMCs decreased, collagen remained constant due to medial thickening, and the glycosaminoglycans increased. Elastic and muscular arteries demonstrate different morphological, mechanical, physiologic, and structural characteristics and adapt differently to aging. While the aortas remodel to preserve the Windkessel function, the SFAs maintain higher longitudinal compliance.

Ex vivo aortic stiffness in mice with different eNOS activity

Endothelial function and NO bioavailability are important determinants of aortic biomechanics and function. With a new technique we investigated the ex vivo aortic segment biomechanics of different mouse models with altered NO signaling. Our experiments clearly show that chronic distortion of NO signaling triggered several compensatory mechanisms that reflect the organism’s attempt to maintain optimal central hemodynamics.

Arterial Stiffness in Hypertension and Function of Large Arteries

BACKGROUND

Arterial stiffness-typically assessed from non-invasive measurement of pulse wave velocity along a straight portion of the vascular tree between the right common carotid and femoral arteries-is a reliable predictor of cardiovascular risk in patients with essential hypertension.

METHODS

We reviewed how carotid-femoral pulse wave velocity increases with age and is significantly higher in hypertension (than in age- and gender-matched individuals without hypertension), particularly when hypertension is associated with diabetes mellitus.

RESULTS

From the elastic aorta to the muscular peripheral arteries of young healthy individuals, there is a gradual but significant increase in stiffness, with a specific gradient. This moderates the transmission of pulsatile pressure towards the periphery, thus protecting the microcirculatory network. The heterogeneity of stiffness between the elastic and muscular arteries causes the gradient to disappear or be inversed with aging, particularly in long-standing hypertension.

CONCLUSIONS

In hypertension therefore, pulsatile pressure transmission to the microcirculation is augmented, increasing the potential risk of damage to the brain, the heart, and the kidney. Furthermore, elevated pulse pressure exacerbates end-stage renal disease, particularly in older hypertensive individuals. With increasing age, the elastin content of vessel walls declines throughout the arterial network, and arterial stiffening increases further due to the presence of rigid wall material such as collagen, but also fibronectin, proteoglycans, and vascular calcification. Certain genes, mainly related to angiotensin and/or aldosterone, affect this aging process and contribute to the extent of arterial stiffness, which can independently affect both forward and reflected pressure waves.

Role of aortic stiffness and inflammation in the etiology of young-onset hypertension

Background/aim

Young-onset hypertension is a form of condition diagnosed in patients aged below 40. Cytokines such as interleukin (IL)-6 and also MCP-1 may play a role in the development of arterial hypertension. Aortic stiffness can be detected by measuring pulse wave velocity (PWV). We aimed to explore the relationship between inflammation and aortic stiffness and investigate their roles in the etiology of young-onset hypertension.

Materials and methods

We enrolled 16 patients diagnosed with young-onset hypertension and 16 volunteers without hypertension. The plasma levels of MCP-1 and IL-6 were determined using an enzyme-linked immunosorbent assay and quantitative enzyme-linked immunoassay, respectively. Carotid-femoral PWV was measured using an arteriograph device.

Results

Compared with those in normotensive controls, the plasma levels of IL-6 and MCP-1 and the PWV values were significantly higher in patients with young-onset hypertension (P < 0.001). PWV values were also positively correlated with the levels of MCP-1 and IL-6. However, no statistically significant difference was noted in intima-media thickness between the two groups (P = 0.224).

Conclusion

In this study, increased PWVs and the levels of inflammation markers were associated with aortic stiffness and inflammation in patients with young-onset hypertension, suggesting they have a role in the etiology of hypertension.

Arterial Stiffness in Patients With Renal Transplantation; Associations With Co-morbid Conditions, Evolution, and Prognostic Importance for Cardiovascular and Renal Outcomes

Patients with chronic kidney disease (CKD), particularly those with end-stage renal disease (ESRD), are at increased risk of cardiovascular events and mortality. The spectrum of arterial remodeling in CKD and ESRD includes atheromatosis of middle-sized conduit arteries and, most importantly, the process of arteriosclerosis, characterized by increased arterial stiffness of aorta and the large arteries. Longitudinal studies showed that arterial stiffness and abnormal wave reflections are independent cardiovascular risk factors in several populations, including patients with CKD and ESRD. Kidney transplantation is the treatment of choice for patients with ESRD, associated with improved survival and better quality of life in relation to hemodialysis or peritoneal dialysis. However, cardiovascular mortality in transplanted patients remains much higher than that in general population, a finding that is at least partly attributed to adverse lesions in the vascular tree of these patients, generated during the progression of CKD, which do not fully reverse after renal transplantation. This article attempts to provide an overview of the field of arterial stiffness in renal transplantation, discussing in detail available studies on the degree and the associations of arterial stiffness with other co-morbidities in renal transplant recipients, the prognostic significance of arterial stiffness for cardiovascular events, renal events and mortality in these individuals, as well as studies examining the changes in arterial stiffness following renal transplantation.

Vascular smooth muscle cell contraction and relaxation in the isolated aorta: a critical regulator of large artery compliance

Over the past few decades, isometric contraction studies of isolated thoracic aorta segments have significantly contributed to our overall understanding of the active, contractile properties of aortic vascular smooth muscle cells (VSMCs) and their cross-talk with endothelial cells. However, the physiological role of VSMC contraction or relaxation in the healthy aorta and its contribution to the pulse-smoothening capacity of the aorta is currently unclear. Therefore, we investigated the acute effects of VSMC contraction and relaxation on the isobaric biomechanical properties of healthy mouse aorta. An in-house developed set-up was used to measure isobaric stiffness parameters of periodically stretched (10 Hz) aortic segments at an extended pressure range, while pharmacologically modulating VSMC tone and endothelial cell function. We found that the effects of α1-adrenergic stimulation with phenylephrine on the pressure-stiffness relationship varied in sensitivity, magnitude and direction, with the basal, unstimulated NO production by the endothelium playing a pivotal role. We also investigated how arterial disease affected this system by using the angiotensin-II-treated mouse. Our results show that isobaric stiffness was increased and that the aortic segments demonstrated a reduced capacity for modulating the pressure-stiffness relationship. This suggests that not only increased isobaric stiffness at normal pressure, but also a reduced capacity of the VSMCs to limit the pressure-associated increase in aortic stiffness, may contribute to the pathogenesis of this mouse model. Overall, this study provides more insight in how aortic VSMC tone affects the pressure-dependency of aortic biomechanics at different physiological and pathological conditions.

The Clinical Significance and Application of Vascular Stiffness Measurements

Increasing evidence points out at vascular stiffness (and in particular aortic stiffness measured by pulse wave velocity) as a reliable biomarker of vascular aging, able to integrate in a single measure the overall burden of cardiovascular (CV) risk factors on the vasculature over time; furthermore, it may be per se a mechanism of disease, by inducing microcirculatory damage and favoring CV events. Increased aortic stiffness has been shown to predict future CV events and improve risk reclassification in those at intermediate risk. However, several questions in this field are still open, limiting the wide use of these tools in the clinical practice. This article will review the basic aspects of physiology of large artery stiffness, as well as current evidence about its possible clinical applications.

Irreversible effects of long-term chronic smoking on arterial stiffness: An analysis focusing on ex-smokers among otherwise healthy middle-aged men

Objective: Smoking is a modifiable cardiovascular risk factor closely related to arterial stiffness (AS). However, data are lacking regarding the chronic effects of smoking on AS, especially in ex-smoker (ES) who faces remnant cardiovascular risk when compared to never-smokers (NS).Methods: Among 1722 health screening participants, we retrospectively evaluated 652 healthy men with different smoking history [240 current smoker (CS) vs. 228 ES vs. 184 NS]. To assess AS, augmentation index (AIx), pulse pressure amplification (PPamp), and carotid-femoral pulse wave velocity (cfPWV) were measured and compared.Results: Baseline characteristics were similar except age and triglyceride level. AIx was lowest in NS, followed by ES, and was highest in CS. PPamp was highest in NS, lowest in CS, and ES was of intermediate level. The differences were more robust after adjustment for baseline covariates (AIx, p = 0.005; PPamp: p = 0.001). On the other hand, no significant intergroup difference was observed for cfPWV in our middle-aged population. With the regression analyses revealing an independent association between smoking duration and AS in ES, subgroup analysis demonstrated that long-term ES (smoking duration ≥20 years) had significantly higher AS than short-term ES (<20 years) and NS, approaching levels comparable to CS (AIx and PPamp: p < 0.0001).Conclusions: Our study demonstrated impaired arterial elastic properties in long-term ES, suggesting that AS caused by chronic smoking might be irreversible even after smoking cessation. Further longitudinal studies are warranted to determine the impacts of past smoking on AS and its clinical relevance.

Sexual Function Is an Indicator of Central Arterial Stiffness and Arterial Stiffness Gradient in Japanese Adult Men

Background

As arterial stiffness increases in the absence of subjective symptoms, a personal indicator that reflects increased risk of cardiovascular disease is necessary. Penile erection is regulated by vascular function, and atherosclerosis affects the penile artery earlier than it affects the coronary and carotid arteries. Therefore, we hypothesized that deterioration of erectile function could be a marker of increased risk for cardiovascular disease. To test our hypothesis, we assessed erectile function and arterial stiffness in a cross‐sectional study.

Methods and Results

Carotid‐femoral pulse wave velocity (PWV), brachial‐ankle PWV, femoral‐ankle PWV, and arterial stiffness gradient (PWV ratio: carotid‐femoral PWV/femoral‐ankle PWV) were measured as indexes of central, systemic, and peripheral arterial stiffness and peripheral organ damage, respectively, in 317 adult men. In addition, erectile function was assessed by using the questionnaire International Index of Erectile Function 5 (a descending score indicates worsening of erectile function). The scores of male sexual function were inversely correlated with carotid‐femoral PWV (r_s=−0.41), brachial‐ankle PWV (r_s=−0.35), femoral‐ankle PWV (r_s=−0.19), and PWV ratio (r_s=−0.33). Furthermore, multivariate linear regression analyses revealed that International Index of Erectile Function 5 scores were significantly associated with carotid‐femoral PWV (β=−0.22) and PWV ratio (β=−0.25), but not with brachial‐ankle PWV and femoral‐ankle PWV.

Conclusions

Our results indicated that erectile function is independently associated with central arterial stiffness and peripheral organ damage. These findings suggest that male sexual function could be an easily identifiable and independent marker of increased central arterial stiffness and peripheral organ damage.

Mismatch between stiffness in elastic and muscular arteries as a predictor of vascular calcification in dialysis patients

BACKGROUND

Vascular calcification is one of the risk factors for arterial stiffness in patients with chronic kidney disease. We hypothesized that a mismatch between elastic and muscular arteries, represented as pulse wave velocity (PWV) ratio, could depict the extent of vascular calcification in end-stage renal disease. We also aimed to compare the predictive PWV ratio value to other factors possibly related to vascular calcification in dialysis population.

METHODS

In this cross-sectional study, in 60 chronic dialysis patients without previous cerebrovascular events, cardiovascular disease and events or clinically evident peripheral artery disease (ankle-brachial index >0.9), carotid-femoral and carotid-radial PWV as well as central hemodynamic parameters were measured by applanation tonometry (SphygmoCor). The PWV ratio using carotid-femoral PWV divided by carotid-radial PWV was calculated. Each patient underwent blood tests and chest X-ray for aortic arch calcification scoring. Two experienced radiologists blinded to patient's medical data evaluated chest X-rays (Cohen's kappa coefficient 0.76) and calculated how many sectors were calcified (Ogawa et al. in Hemodial Int 13:301-306, 2009). Differently scored chest X-rays were repeatedly reviewed and a consensus was reached.

RESULTS

The study population consisted of 31 (51.7%) males and 29 (48.3%) females, mean age 52.73 ± 13.76 years. Increased risk for aortic arch calcification was associated with higher PWV ratio even after adjustment for age, height, heart rate, ferritin level and C-reactive protein level (OR 2.59E+04, 95% CI 2.43E+01, 2.65E+09, p = 0.021). PWV ratio together with above-mentioned variables could predict the presence of aortic arch calcification with specificity of 93% (95% CI 78, 99%) and sensitivity of 53% (95% CI 34, 72%).

CONCLUSION

The elastic and muscular arteries' stiffness mismatch was strongly associated with the extent of aortic arch calcification in this dialysis population and had better calcification predictive value compared to other demographic, hemodynamic and biochemical markers.

Association of asymptomatic target organ damage with secreted frizzled related protein 5 in the elderly: the Northern Shanghai Study

Objective

Secreted frizzled related protein 5 (SFRP5) is a novel anti-inflammatory adipokine that is implicated in metabolic and cardiovascular disease (CVD). However, little is known about the relevance of SFRP5 with asymptomatic hypertensive target organ damages (TODs). We aimed to investigate the association between SFRP5 and TOD in a large population.

Clinical trial registration

NCT02368938.

Methods

A total of 1,745 community-dwelling elderly subjects aged over 65 years from northern Shanghai were recruited in the study. Plasma SFRP5 level was measured by an enzyme-linked immunosorbent assay. Asymptomatic TODs, including left ventricular mass index, peak transmitral pulsed Doppler velocity/early diastolic tissue Doppler velocity, carotid intima–media thickness (CIMT), pulse wave velocity (PWV), estimated glomerular filtration rate, and urinary albumin–creatinine ratio were evaluated.

Results

Plasma SFRP5 level was negatively associated with body mass index, waist/hip ratio, and fasting blood glucose (all P<0.001). Men, compared with women, had lower plasma SFRP5 level (4.19 vs 5.13 ng/mL, P<0.001). Additionally, plasma SFRP5 level was lower in diabetics than in those without diabetes (4.30 vs 4.81 ng/mL, P<0.05). Furthermore, an inverse association was observed between SFRP5 and PWV and CIMT (both P<0.05). Lastly, the multivariate logistic regression analysis showed lower SFRP5 level was significantly associated with increased arterial stiffness in the elderly (odds ratio 0.83, 95% confidence interval 0.71 to 0.99 per 1 standard deviation increase, P<0.05).

Conclusion

Plasma SFRP5 level was inversely correlated with conventional cardiovascular risk factors, and low plasma SFRP5 was also significantly associated with arterial stiffening in the elderly Chinese population.

Association between serum total homocysteine and arterial stiffness in adults: a community-based study

Both increased arterial stiffness and higher total homocysteine (tHcy) are associated with an elevated risk for cardiovascular disease. However, the relationship between tHcy and arterial stiffness is still inconclusive. The authors aimed to test the relationship of tHcy with carotid-femoral pulse wave velocity (cfPWV) and examine the possible effect modifiers in adults. A study was conducted from July to September 2016 in Jiangsu Province, China. A total of 16 644 participants were enrolled in the final analysis. Increased arterial stiffness is defined as a cfPWV ≥10 m/s. Overall, there was a positive association between tHcy and cfPWV levels (per 5-μmol/L tHcy increase: β = 0.10; 95% confidence interval [CI], 0.08-0.13) and increased arterial stiffness (per 5-μmol/L tHcy increase: odds ratio, 1.11; 95% CI, 1.07-1.14). Compared with participants with tHcy <10 μmol/L, the significantly higher cfPWV levels were observed in those with tHcy ≥15 μmol/L (β = 0.37; 95% CI, 0.28-0.47). Accordingly, a higher prevalence of increased arterial stiffness was found in patients with tHcy10 to <15 μmol/L (odds ratio, 1.18; 95% CI, 1.05-1.33) and tHcy ≥15 μmol/L (odds ratio, 1.50; 95% CI, 1.32-1.71) as compared with participants with tHcy <10 μmol/L. Furthermore, the stronger positive association was found in participants who were older (≥60 years, P for interaction = .008), had low body mass index (<25 kg/m² , P for interaction = .026), high systolic blood pressure levels (≥145 mm Hg [median], P for interaction = .048), or diabetes mellitus (P for interaction = .045). The present study demonstrated that serum tHcy concentrations were positively associated with cfPWV and the prevalence of increased arterial stiffness. These results suggest that the cardiovascular effects of tHcy may partly be mediated through arterial stiffness.

Pulse wave velocity differs between ulcerative colitis and chronic kidney disease

BACKGROUND

We hypothesized that a reversal of the physiological stiffness gradient, previously reported in end-stage renal disease, begins in the early stages of chronic kidney disease (CKD) and that chronic inflammation produces a different arterial phenotype in patients with ulcerative colitis (UC).

OBJECTIVES

To assess the extent of arterial stiffening in the central (carotid-femoral pulse wave velocity, cf.-PWV) and peripheral arteries (carotid-radial pulse wave velocity, cr-PWV) and to explore the determinants of the stiffness gradient in UC and in CKD.

METHODS

We enrolled 45 patients with UC, 45 patients with stage 3-4 CKD and 45 matched controls.

RESULTS

Despite the comparable cf.-PWV, the cr-PWV was higher in patients with UC than in those with CKD (median: 8.7 vs. 7.5m/s; p<0.001) and, consequently, the PWV ratio was lower (median: 0.97 vs. 1.12; p<0.001). In patients with CKD a stiffness mismatch was reported starting from stage 3B. The PWV ratio was associated with age and C-reactive protein (beta: 0.08 z-score, 95%CI 0.02-0.14; p=0.01) or active disease (beta: 0.43 z-score, 95%CI 0.003-0.857; p=0.048) in patients with UC and with age and glomerular filtration rate (beta: -0.56 z-score, 95%CI -1.05 to -0.07; p=0.02) in patients with CKD.

CONCLUSIONS

The arterial phenotype differed between UC and CKD. The reversal of the arterial stiffness gradient is evident in CKD patients starting from stage 3B but not in patients with UC and comparable cf.-PWV. In patients with UC, the stiffness of both elastic and muscular arteries is increased as a consequence of inflammation.

Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments

Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10%) than muscular arteries (2%). As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC). The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α₁-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor) and/or 35 μM diltiazem (blocker of voltage-gated Ca²⁺ channels) were measured. As compared with static or cyclic stretch at low amplitude (<10 mN) or low frequency (0.1 Hz), cyclic stretch at physiological amplitude (>10 mN) and frequency (1–10 Hz) caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME), physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca²⁺ and shifted the smaller tonic contraction more from a voltage-gated Ca²⁺ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and vascular smooth muscle cells to maintain basal NO release and low intracellular Ca²⁺ in the smooth muscle cells in large arteries. Both phenomena may play a vital role in maintaining the high compliance of large arteries.

eGFRs from Asian-modified CKD-EPI and Chinese-modified CKD-EPI equations were associated better with hypertensive target organ damage in the community-dwelling elderly Chinese: the Northern Shanghai Study

Background

With increasing age, estimated glomerular filtration rate (eGFR) decline is a frequent manifestation and is strongly associated with other preclinical target organ damage (TOD). In literature, many equations exist in assessing patients’ eGFR. However, these equations were mainly derived and validated in the population from Western countries, which equation should be used for risk stratification in the Chinese population remains unclear, as well as their comparison. Considering that TOD is a good marker for risk stratification in the elderly, in this analysis, we aimed to investigate whether the recent eGFR equations derived from Asian and Chinese are better associated with preclinical TOD than the other equations in elderly Chinese.

Methods

A total of 1,599 community-dwelling elderly participants (age >65 years) in northern Shanghai were prospectively recruited from June 2014 to August 2015. Conventional cardiovascular risk factors were assessed, and hypertensive TOD including left ventricular mass index (LVMI), carotid–femoral pulse wave velocity (cf-PWV), carotid intima-media thickness (IMT), ankle–brachial index (ABI) and urine albumin to creatinine ratio (UACR) was evaluated for each participant. Participant’s eGFR was calculated from the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Chinese-abbreviated MDRD (c-aMDRD), Asian-modified CKD-EPI (aCKD-EPI) equation and Chinese-modified CKD-EPI (cCKD-EPI) equation.

Results

In multivariate regression analysis, only eGFRs from aCKD-EPI were significantly and inversely associated with carotid IMT (P=0.005). In multivariate logistic models, decreased eGFR from all the equations were significantly associated with lower ABI (P<0.001), microalbuminuria (P=0.02 to P<0.001) and increased cf-PWV (P<0.001). Only decreased eGFRs from aCKD-EPI and cCKD-EPI equations were significantly associated with increased IMT (both crude P<0.05). In the receiver operator characteristic (ROC) analysis, only aCKD-EPI and cCKD-EPI equations presented significant associations with all the listed preclinical TODs (P-value from <0.05 to <0.001).

Conclusion

In community-dwelling elderly Chinese, eGFRs from aCKD-EPI and cCKD-EPI equations are better associated with preclinical TOD. aCKD-EPI and cCKD-EPI equations should be preferred when making risk assessment.

Cardiometabolic risk factors in children with celiac disease on a gluten-free diet

Celiac disease (CD) is an immune-mediated systemic condition evoked by gluten and related prolamines in genetically predisposed subjects. It is characterised by a variable combination of gluten-dependent clinical symptoms, CD-specific antibodies, HLA-DQ2 and HLA-DQ8 haplotypes, and enteropathy. The only therapy of CD consists of a life-long gluten free diet (GFD). Strict GFD adherence results in full clinical, serological and histological remission, avoiding long-term complications in CD patients. However, this diet is not without problems. Gluten free products have high levels of lipids, sugar and salt to improve food palatability and consistency, and subjects with CD show an excessive consumption of hypercaloric and hyperlipidic foods to compensate dietetic restriction. GFD may therefore have a negative impact on cardiometabolic risk factors such as obesity, serum lipid levels, insulin resistance, metabolic syndrome, and atherosclerosis. In adults, some studies have suggested that GFD have a beneficial effect on cardiovascular profile, whereas others have shown an atherogenic effect of GFD. In children, very few studies are available on the issue. Thus, the aim of the present narrative review was to analyze the current clinical evidence on the impact of GFD on cardiometabolic risk factors in children with CD.

Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments

Most vaso-reactive studies in mouse aortic segments are performed in isometric conditions and at an optimal preload, which is the preload corresponding to a maximal contraction by non-receptor or receptor-mediated stimulation. In general, this optimal preload ranges from about 1.2 to 8.0 mN/mm, which according to Laplace's law roughly correlates with transmural pressures of 10-65 mmHg. For physiologic transmural pressures around 100 mmHg, preloads of 15.0 mN/mm should be implemented. The present study aimed to compare vascular reactivity of 2 mm mouse (C57Bl6) aortic segments preloaded at optimal (8.0 mN/mm) vs. (patho) physiological (10.0-32.5 mN/mm) preload. Voltage-dependent contractions of aortic segments, induced by increasing extracellular K⁺, and contractions by α₁-adrenergic stimulation with phenylephrine (PE) were studied at these preloads in the absence and presence of L-NAME to inhibit basal release of NO from endothelial cells (EC). In the absence of basal NO release and with higher than optimal preload, contractions evoked by depolarization or PE were attenuated, whereas in the presence of basal release of NO PE-, but not depolarization-induced contractions were preload-independent. Phasic contractions by PE, as measured in the absence of external Ca²⁺, were decreased at higher than optimal preload suggestive for a lower contractile SR Ca²⁺ content at physiological preload. Further, in the presence of external Ca²⁺, contractions by Ca²⁺ influx via voltage-dependent Ca²⁺ channels were preload-independent, whereas non-selective cation channel-mediated contractions were increased. The latter contractions were very sensitive to the basal release of NO, which itself seemed to be preload-independent. Relaxation by endogenous NO (acetylcholine) of aortic segments pre-contracted with PE was preload-independent, whereas relaxation by exogenous NO (diethylamine NONOate) displayed higher sensitivity at high preload. Results indicated that stretching aortic segments to higher than optimal preload depolarizes the SMC and causes Ca²⁺ unloading of the contractile SR, making them extremely sensitive to small changes in the basal release of NO from EC as can occur in hypertension or arterial stiffening.

Comparison of Carotid-Femoral and Brachial-Ankle Pulse-Wave Velocity in Association With Target Organ Damage in the Community-Dwelling Elderly Chinese: The Northern Shanghai Study

Background

Carotid‐femoral pulse‐wave velocity (cf‐PWV) and brachial‐ankle PWV (ba‐PWV) are the 2 most frequently applied PWV measurements. However, little is known about the comparison of hypertensive target organ damage (TOD) with cf‐PWV and ba‐PWV.

Methods and Results

A total of 1599 community‐dwelling elderly subjects (age >65 years) in northern Shanghai were recruited from June 2014 to August 2015. Both cf‐PWV and ba‐PWV were measured using SphygmoCor and VP1000 systems, respectively. Within the framework of comprehensive cardiovascular examinations, risk factors were assessed, and asymptomatic TOD, including left ventricular mass index, peak transmitral pulsed Doppler velocity/early diastolic tissue Doppler velocity (E/Ea), carotid intima‐media thickness, arterial plaque, creatinine clearance rate, and urinary albumin‐creatinine ratio were all evaluated. Both PWVs were significantly associated with male sex, age, waist/hip circumference, fasting plasma glucose, and systolic blood pressure, and ba‐PWV was also significantly related to body mass index. Both PWVs were significantly correlated with most TOD. When cf‐PWV and ba‐PWV were both or separately put into the stepwise linear regression model together with cardiovascular risk factors and treatment, only cf‐PWV, but not ba‐PWV, was significantly associated with carotid intima‐media thickness and creatinine clearance rate (P<0.05). When cf‐PWV and ba‐PWV were both or separately put into the same full‐mode model after adjustment for confounders, only cf‐PWV, but not ba‐PWV, showed significant association with carotid intima‐media thickness and creatinine clearance rate (P<0.05). Similar results were observed in logistic regression analysis.

Conclusions

Taken together, in the community‐dwelling elderly Chinese, cf‐PWV seems to be more closely associated with hypertensive TOD, especially vascular and renal TOD, as compared with ba‐PWV.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02368938.

Development of Coronary Pulse Wave Velocity: New Pathophysiological Insight Into Coronary Artery Disease

Background

Although aortic stiffness assessed by pulse wave velocity (PWV) is a strong predictor of coronary artery disease, the significance of local coronary stiffness has never been tackled. The first objective of this study was to describe a method of measuring coronary PWV (CoPWV) invasively and to describe its determinants. The second objective was to assess both CoPWV and aortic PWV in patients presenting with acute coronary syndromes or stable coronary artery disease.

Methods and Results

In 53 patients, CoPWV was measured from the delay in pressure wave and distance traveled as a pressure wire was withdrawn from the distal to the proximal coronary segment. Similarly, aortic PWV was measured invasively when the wire was pulled across the ascending aorta; carotid–femoral PWV was also measured noninvasively using the SphygmoCor system (AtCor Medical). Mean CoPWV was 10.3±6.1 m/s. Determinants of increased CoPWV were fractional flow reserve, diastolic blood pressure, and previous stent implantation in the recorded artery. CoPWV was lower in patients with acute coronary syndromes versus stable coronary artery disease (7.6±3 versus 11.5±6.4 m/s; P=0.02), and this persisted after adjustment for confounders. In contrast, aortic stiffness, assessed by aortic and carotid–femoral PWV, did not differ significantly.

Conclusions

CoPWV seems associated with acute coronary events more closely than aortic PWV. High coronary compliance, whether per se or because it leads to a distal shift in compliance mismatch, may expose vulnerable plaques to high cyclic stretch. CoPWV is a new tool to assess local compliance at the coronary level; it paves the way for a new field of research.

The Effects of Hemodynamic Changes on Pulse Wave Velocity in Cardiothoracic Surgical Patients

The effect of blood pressure on pulse wave velocity (PWV) is well established. However, PWV variability with acute hemodynamic changes has not been examined in the clinical setting. The aim of the present study is to investigate the effect of hemodynamic changes on PWV in patients who undergo cardiothoracic surgery. Using data from 25 patients, we determined blood pressure (BP), heart rate (HR), and the left ventricular outflow tract (LVOT) velocity-time integral. By superimposing the radial arterial waveform on the continuous wave Doppler waveform of the LVOT, obtained by transesophageal echo, we were able to determine pulse transit time and to calculate PWV, stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR). Increases in BP, HR, and SVR were associated with higher values for PWV. In contrast increases in SV were associated with decreases in PWV. Changes in CO were not significantly associated with PWV.

Pulse wave velocity in elastic and muscular arteries: tracking stability and association with anthropometric and hemodynamic measurements

Pulse wave velocity (PWV) has been used as a measurement for arterial stiffness, a predictor of cardiovascular risk. Tracking describes the stability of a measurement over time. The purpose of this study was to evaluate the tracking stability of carotid-femoral (cfPWV), carotid-radial (crPWV) and carotid-distal (cdPWV) PWV in young adults and their associations with anthropometric and hemodynamic measurements. cfPWV, crPWV and cdPWV were measured by tonometric (SphygmoCor) technique in 531 subjects (aged 23.7±4.9 with 42.9% African Americans and 49.9% females). Out of these subjects, 142 subjects had all these 3 PWV measurements evaluated again during their next visit with an average follow-up time of 2 years. In the tracking analysis on the data from the 142 subjects, cfPWV displayed moderate to relatively high tracking ability (r=0.61, P<0.001), whereas crPWV and cdPWV only displayed low to moderate tracking coefficients (r=0.29 and r=0.36 respectively, P<0.001). In the association test on the data from the 531 subjects, all three PWV measurements showed significant correlations with age and obesity related measurements. cfPWV displayed stronger correlations with these parameters. In addition, all three PWVs showed significant correlations with systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure with the exception that no correlation existed between crPWV and pulse pressure. The higher tracking ability of cfPWV and its higher association with obesity related measurements highlights the importance of using cfPWV compared with crPWV and cdPWV for research and clinical settings.

Quantification of the Interrelationship between Brachial-Ankle and Carotid-Femoral Pulse Wave Velocity in a Workplace Population

BACKGROUND

Brachial-ankle pulse wave velocity (PWV) is increasingly used for the measurement of arterial stiffness. In the present study, we quantified the interrelationship between brachial-ankle and carotid-femoral PWV in a workplace population, and investigated the associations with cardiovascular risk factors and carotid intima-media thickness (IMT).

METHODS

Brachial-ankle and carotid-femoral PWV were measured using the Omron-Colin VP1000 and SphygmoCor devices, respectively. We investigated the interrelationship by the Pearson's correlation analysis and Bland-Altman plot, and performed sensitivity and specificity analyses.

RESULTS

The 954 participants (mean ± standard deviation age 42.6 ± 14.2 years) included 630 (66.0%) men and 203 (21.3%) hypertensive patients. Brachial-ankle (13.4 ± 2.7 m/s) and carotid-femoral PWV (7.3 ± 1.6 m/s) were significantly correlated in all subjects (r = 0.75) as well as in men (r = 0.72) and women (r = 0.80) separately. For arterial stiffness defined as a carotid-femoral PWV of 10 m/s or higher, the sensitivity and specificity of brachial-ankle PWV of 16.7 m/s or higher were 72 and 94%, respectively. The area under the receiver operating characteristic curve was 0.953. In multiple stepwise regression, brachial-ankle and carotid-femoral PWV were significantly (p < 0.001) associated with age (partial r = 0.33 and 0.34, respectively) and systolic blood pressure (partial r = 0.71 and 0.66, respectively). In addition, brachial-ankle and carotid-femoral PWV were significantly (p < 0.001) associated with carotid IMT (r = 0.57 and 0.55, respectively) in unadjusted analysis, but not in analysis adjusted for cardiovascular risk factors (p ≥ 0.08).

CONCLUSIONS

Brachial-ankle and carotid-femoral PWV were closely correlated, and had similar determinants. Brachial-ankle PWV can behave as an ease-of-use alternative measure of arterial stiffness for assessing cardiovascular risk.

Assessment of arterial stiffness from pedal artery Korotkoff sound recordings: feasibility and potential utility

Brachial artery (BA) Korotkoff sound (KS) timing reflects arterial stiffness. We recorded pedal artery (PA) KS in 68 healthy subjects using an electronic stethoscope and electrocardiography. Intervals between QRS complex of the electrocardiogram and KS waveform peaks (termed the QKD interval) were measured for 60 seconds, averaged, and QKD velocity (v) calculated. Carotid-BA and carotid-PA pulse wave velocities (PWVs) were measured by applanation tonometry. Analyzable KS recordings were obtained from BA and PA in 100% and 92% subjects. PA QKDv decreased less than BA QKDv with progressive cuff inflation. At diastolic blood pressure + 20 mm Hg (maximal yield), BA QKDv was independently associated with weight and pulse pressure, whereas PA QKDv was related to weight and age. PA QKDv correlated with its corresponding PWV stronger than BA QKDv. In conclusion, PA KS is optimally recorded at diastolic blood pressure + 20 mm Hg; PA QKDv is correlated with age and better correlates with PWV than does BA QKDv. This technique may provide a simple arterial stiffness measure.

Elastic and Muscular Arteries Differ in Structure, Basal NO Production and Voltage-Gated Ca(2+)-Channels

In the last decades, the search for mechanisms underlying progressive arterial stiffening and for interventions to avoid or reverse this process has gained much attention. In general, arterial stiffening displays regional variation and is, for example, during aging more prominent in elastic than in muscular arteries. We hypothesize that besides passive also active regulators of arterial compliance [i.e., endothelial and vascular smooth muscle cell (VSMC) function] differ between these arteries. Hence, it is conceivable that these vessel types will display different time frames of stiffening. To investigate this hypothesis segments of muscular arteries such as femoral and mesenteric arteries and elastic arteries such as the aorta and carotid artery were isolated from female C57Bl6 mice (5–6 months of age, n = 8). Both microscopy and passive stretching of the segments in a myograph confirmed that passive mechanical properties (elastin, collagen) of elastic and muscular arteries were significantly different. Endothelial function, more specifically basal nitric oxide (NO) efficacy, and VSMC function, more specifically L-type voltage-gated Ca²⁺ channel (VGCC)-mediated contractions, were determined by α₁-adrenoceptor stimulation with phenylephrine (PE) and by gradual depolarization with elevated extracellular K⁺ in the absence and presence of eNOS inhibition with L-NAME. PE-mediated isometric contractions significantly increased after inhibition of NO release with L-NAME in elastic, but not in muscular vessel segments. This high basal eNOS activity in elastic vessels was also responsible for shifts of K⁺ concentration-contraction curves to higher external K⁺. VGCC-mediated contractions were similarly affected by depolarization with elevated K⁺ in muscular artery segments or in elastic artery segments in the absence of basal NO. However, K⁺-induced contractions were inhibited by the VGCC blocker diltiazem with significantly higher sensitivity in the muscular arteries, suggestive of different populations of VGCC isoforms in both vessel types. The results from the present study demonstrate that, besides passive arterial wall components, also active functional components contribute to the heterogeneity of arterial compliance along the vascular tree. This crucially facilitates the search for (patho) physiological mechanisms and potential therapeutic targets to treat or reverse large artery stiffening as occurring in aging-induced arterial stiffening.

Impact of body tilt on the central aortic pressure pulse

The present work was undertaken to investigate, in young healthy volunteers, the relationships between the forward propagation times of arterial pressure waves and the timing of reflected waves observable on the aortic pulse, in the course of rapid changes in body position. 20 young healthy subjects, 10 men, and 10 women, were examined on a tilt table at two different tilt angles, −10° (Head-down) and + 45° (Head-up). In each position, carotid-femoral (T_cf) and carotid-tibial forward propagation times (T_ct) were measured with the Complior device. In each position also, the central aortic pressure pulse was recorded with radial tonometry, using the SphygmoCor device and a generalized transfer function, so as to evaluate the timing of reflected waves reaching the aorta in systole (onset of systolic reflected wave, sT1r) and diastole (mean transit time of diastolic reflected wave, dMTT). The position shift from Head-up to Head-down caused a massive increase in both T_ct (women from 130 ± 10 to 185 ± 18 msec P < 0.001, men from 136 ± 9 to 204 ± 18 msec P < 0.001) and dMTT (women from 364 ± 35 to 499 ± 33 msec P < 0.001, men from 406 ± 22 to 553 ± 21 msec P < 0.001). Mixed model regression showed that the changes in T_ct and dMTT observed between Head-up and Head-down were tightly coupled (regression coefficient 2.1, 95% confidence interval 1.9–2.3, P < 0.001). These results strongly suggest that the diastolic waves observed on central aortic pulses reconstructed from radial tonometric correspond at least in part to reflections generated in the lower limbs.

Aortic-Brachial Stiffness Mismatch and Mortality in Dialysis Population

We hypothesized that increased aortic stiffness (central elastic artery) combined with a decrease in brachial stiffness (peripheral muscular artery) leads to the reversal of the physiological stiffness gradient (ie, mismatch), promoting end-organ damages through increased forward pressure wave transmission into the microcirculation. We, therefore, examined the effect of aortic-brachial stiffness mismatch on mortality in patients in need of dialysis. In a prospective observational study, aortic-brachial arterial stiffness mismatch (pulse wave velocity ratio) was assessed using carotid-femoral pulse wave velocity divided by carotid-radial pulse wave velocity in 310 adult patients on dialysis. After a median follow-up of 29 months, 146 (47%) deaths occurred. The hazard ratio (HR) for mortality related to PWV ratio in a Cox regression analysis was 1.43 (95% confidence interval [CI], 1.24–1.64; P <0.001 per 1 SD) and was still significant after adjustments for confounding factors, such as age, dialysis vintage, sex, cardiovascular disease, diabetes mellitus, smoking status, and weight (HR, 1.23; 95% CI: 1.02–1.49). The HRs for changes in 1 SD of augmentation index (HR, 1.35; 95% CI, 1.12–1.63), carotid-femoral pulse wave velocity (HR, 1.29; 95% CI, 1.11–1.50), and carotid-radial pulse wave velocity (HR, 0.80; 95% CI, 0.67–0.95) were statistically significant in univariate analysis, but were no longer statistically significant after adjustment for age. In conclusion, aortic-brachial arterial stiffness mismatch was strongly and independently associated with increased mortality in this dialysis population. Further studies are required to confirm these finding in lower-risk groups.

Comparison of pulse wave velocity assessed by three different techniques: Arteriograph, Complior, and Echo-tracking

Arterial stiffness estimated by pulse wave velocity (PWV) is an independent predictor of cardiovascular morbidity and mortality. Although recommended by the current guidelines, clinical applicability of this parameter is difficult, due to differences between the various techniques used to measure it and to biological variability. Our aim was to compare PWV assessed by 3 different commercially available systems. 100 subjects (51 ± 16 years, 45 men) were evaluated using the 3 methods: an oscillometric technique (Arteriograph, PWV-A); a piezo-electric method (Complior, PWV-C); and an high-resolution ultrasound technique implemented with an Echo-tracking system (Aloka, PWV-E). Conventional biological markers were measured. Correlations of PWV measured by the 3 methods were poor (r = 0.39, r = 0.39, and r = 0.31 for PWV-A vs. PWV-C, PWV-A vs. PWV-E, and PWV-C vs. PWV-E, respectively, all p < 0.05). By Bland-Altman analysis, mean difference (±SD) of PWV-A vs. PWV-C was -1.9 ± 2.0 m/s, of PWV-A vs. PWV-E -3.6 ± 1.9 m/s, and of PWV-C vs. PWV-E -2.7 ± 1.9 m/s, with a wide coefficient of variation (22.3, 25.7, and 25.7 %, respectively). As expected, PWV-A, PWV-C, and PWV-E correlated with other arterial stiffness parameters, such as intima-media thickness (r = 0.22, r = 0.22, and r = 0.36, respectively), E p (r = 0.37, r = 0.26, and r = 0.94, respectively), and augmentation index measured by Arteriograph method (r = 0.66, r = 0.35, and r = 0.26, respectively); all p < 0.05. Assessment of PWV is markedly dependent on the technique used to measure it, related to various methods for measuring traveled distance of the arterial wave. Our results suggest the urgent need to establish reference values of PWV for each of these techniques, separately, to be used in routine clinical practice.

Natriuresis and blood pressure reduction in hypertensive patients with diabetes mellitus: the NESTOR study

The antihypertensive effect of indapamide has never been clearly understood, particularly in hypertensive patients with diabetes mellitus. A total of 565 patients were randomly selected to receive either indapamide 1.5 mg or enalapril 10 mg daily for 12 months. Brachial blood pressure (BP) and plasma and urinary electrolytes were measured at baseline and at the end of follow-up. Sodium and potassium levels and excretion rates were measured in overnight urine collections. After 12 months' treatment, similar significant reductions were observed in systolic and diastolic BP and pulse pressure levels in both treatment arms (P < .001). However, age, body mass index, diabetes duration, and plasma sodium reductions were shown to be major, independent factors influencing BP reduction with indapamide, but not with enalapril. Regression coefficients were positive for age and plasma sodium reductions (P ≤ .009) but negative for body mass index and diabetes duration (P ≤ .008). Similar findings were observed for pulse pressure. These results were more notable in elderly patients, did not differ regardless of whether BP reduction was measured in absolute or percent values, and were associated with increased sodium and potassium excretion rates.Indapamide is more effective than enalapril at reducing BP in elderly diabetic hypertensives with marked sodium retention.

Low plasma renalase concentration in hypertensive patients after surgical repair of coarctation of aorta

The study aimed to evaluate plasma renalase level, a recently discovered kidney-derived catecholamine-metabolizing enzyme in patients after successful repair of aortic coarctation, with special consideration of arterial hypertension in the context of underlying process of arterial remodeling. This case-control study covered 50 consecutive patients after Dacron patch repair of aortic coarctation (31 men; median age 33 [26; 40]; age at surgery 10 [5; 16] years), matched in terms of age and gender with 50 controls. Both groups were stratified depending on the presence of hypertension and assessed in terms of renalase, C-reactive protein, and carotid intima-media thickness. Additionally ultrasound and tonometric markers of vascular remodeling were obtained in the study group. Hypertension was found in 21 patients (42%) in the study group and 29 (58%) in the control group (P = .11). Renalase level was significantly lower in patients in the study than control group (5825.1 vs. 6592.7 ng/mL; P = .041). Significant difference in terms of renalase concentration between hypertensive and normotensive patients was confirmed both in subjects with coarctation of aorta (P = .027) and in control group (P < .0001). Renalase level inversely correlated with serum creatinine (r = -0.36) and arterial blood pressure in the whole population, and with central systolic (r = -0.29) and diastolic pressure (r = -0.35) in study group. Multivariate regression revealed that serum creatinine and pulse pressure were independent predictors of renalase. Surgical intervention >7 years was linked to lower renalase (P = .018) and unfavorable vascular parameters. Renalase level <4958 ng/mL accurately predicted presence of hypertension in patients after coarctation of aorta repair (odds ratio, 3.8; P = .032). Renalase deficiency is associated with the presence of hypertension in both patients after surgical repair of aortic coarctation and the control group. In coarctation of aorta, its action is probably parallel to underlying arterial remodeling.

Determinants of brachial-ankle pulse wave velocity in Chinese patients with rheumatoid arthritis

Objective. To investigate the relationship between Brachial-ankle pulse wave velocity (baPWV), and its associated risk factors in Chinese patients with RA. Methods. 138 Chinese RA patients and 150 healthy subjects were included. baPWV of all the participants was measured. RA related factors were determined, as well as traditional cardiovascular risk factors. Results. baPWV was significant higher in RA group (1705.44 ± 429.20 cm/s) compared to the healthy control group (1386.23 ± 411.09 cm/s) (P < 0.001). Compared with low baPWV group, high baPWV group patients were significantly older (P = 0.008) and taller (P = 0.033). Serum cholesterol (P = 0.035), triglycerides (P = 0.004), and LDL level (P = 0.006) were significantly higher in high baPWV group patients compared with low baPWV group patients. The baPWV of RA patients was positively correlated with age (r = 0.439, P < 0.001), and serum cholesterol level (r = 0.231, P = 0.035), serum triglycerides level (r = 0.293, P < 0.001), serum LDL level (r = 0.323, P = 0.003). Meanwhile, baPWV negatively correlated with the height of RA patients (r = −0.253, P = 0.043). Multivariate regression analysis showed that baPWV of RA group was independently associated with age and serum triglycerides level. Conclusions. The old age and high level of serum triglycerides may be the major determinants of arterial stiffness in Chinese RA patients.