Should the augmentation index be normalized to heart rate?

Hypertension and Elevated Pulse Pressure Responsive to Biomass Pollutants Exposures in Young Workers From the Democratic Republic of Congo: A Cross-Sectional Analysis

BACKGROUND

Occupational biomass pollutant exposure as observed in charcoal workers may have significant cardiovascular effects. This study aims to ascertain the prevalence and risk factors of hypertension and high pulse pressure (HPP), a marker of arterial stiffness, in charcoal workers compared with a control group of agricultural workers from the Democratic Republic of Congo.

METHODS AND RESULTS

The charcoal worker and agricultural worker groups (n=485; median age, 35-40 years) were composed of male charcoal producers (n=229), charcoal saleswomen (n=72), male farmers (n=118), and vegetable saleswomen (n=66). We assessed workplace air pollution, sociodemographic parameters, self-reported physical activity, body composition, exhaled air carbon monoxide, and blood pressure. Hypertension and HPP prevalences were determined. Logistic regression, adjusted for confounding variables was used to identify the risk factors. Charcoal workplaces were more polluted than agricultural workplaces (P<0.01). Charcoal producers performed higher levels of physical activity (P=0.018) and demonstrated higher levels of exhaled air carbon monoxide (P<0.0001) and pulse pressure (P=0.006), and higher prevalence of grade 1 hypertension (P=0.007), isolated systolic hypertension (P=0.04), and HPP (P=0.02) than farmers. Overall, hypertension (adjusted odds ratio [aOR], 11.76 [95% CI, 6.26-22.13]), level of particulate matter <10 μm pollutants (aOR, 1.001 [95% CI, 1.0002-1.0017]), smoking (aOR, 2.21 [95% CI, 1.15-4.24]) and low education (aOR, 2.14 [95% CI, 1.10-4.17]) were independently associated with HPP. The level of particulate matter <1.0 μm pollutants (aOR, 1.0009 [95% CI, 1.0002-1.0015]), male sex (aOR, 2.09 [95% CI, 1.21-3.64]), and job seniority (aOR, 1.022 [95% CI, 1.004-1.044]) were independently associated with isolated systolic hypertension.

CONCLUSIONS

Charcoal producers appear to develop isolated systolic hypertension and HPP more, both indices of cardiovascular events in which occupational biomass particles seem to play an early significant role.

Non-invasive parameters of autonomic function using beat-to-beat cardiovascular variations and arterial stiffness in hypertensive individuals: a systematic review

PURPOSE

Non-invasive, beat-to-beat variations in physiological indices provide an opportunity for more accessible assessment of autonomic dysfunction. The potential association between the changes in these parameters and arterial stiffness in hypertension remains poorly understood. This systematic review aims to investigate the association between non-invasive indicators of autonomic function based on beat-to-beat cardiovascular signals with arterial stiffness in individuals with hypertension.

METHODS

Four electronic databases were searched from inception to June 2022. Studies that investigated non-invasive parameters of arterial stiffness and autonomic function using beat-to-beat cardiovascular signals over a period of > 5min were included. Study quality was assessed using the STROBE criteria. Two authors screened the titles, abstracts, and full texts independently.

RESULTS

Nineteen studies met the inclusion criteria. A comprehensive overview of experimental design for assessing autonomic function in terms of baroreflex sensitivity and beat-to-beat cardiovascular variabilities, as well as arterial stiffness, was presented. Alterations in non-invasive indicators of autonomic function, which included baroreflex sensitivity, beat-to-beat cardiovascular variabilities and hemodynamic changes in response to autonomic challenges, as well as arterial stiffness, were identified in individuals with hypertension. A mixed result was found in terms of the association between non-invasive quantitative autonomic indices and arterial stiffness in hypertensive individuals. Nine out of 12 studies which quantified baroreflex sensitivity revealed a significant association with arterial stiffness parameters. Three studies estimated beat-to-beat heart rate variability and only one study reported a significant relationship with arterial stiffness indices. Three out of five studies which studied beat-to-beat blood pressure variability showed a significant association with arterial structural changes. One study revealed that hemodynamic changes in response to autonomic challenges were significantly correlated with arterial stiffness parameters.

CONCLUSIONS

The current review demonstrated alteration in autonomic function, which encompasses both the sympathetic and parasympathetic modulation of sinus node function and vasomotor tone (derived from beat-to-beat cardiovascular signals) in hypertension, and a significant association between some of these parameters with arterial stiffness. By employing non-invasive measurements to monitor changes in autonomic function and arterial remodeling in individuals with hypertension, we would be able to enhance our ability to identify individuals at high risk of cardiovascular disease. Understanding the intricate relationships among these cardiovascular variability measures and arterial stiffness could contribute toward better individualized treatment for hypertension in the future.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID: CRD42022336703. Date of registration: 12/06/2022.

Stimulation of the Vascular Endothelium and Angiogenesis by Blood-Flow-Restricted Exercise

Blood-flow-restricted exercise (BFRE) has been gaining constantly increasing interest in rehabilitation, but its influence on endothelial functions has not been well studied yet. Our aim is to examine the influence of low-resistance BFRE on endothelial functions and angiogenesis. This prospective cross-over study involved 35 young healthy adults. They conducted a 21-min low-resistant exercise with blood flow restricted by pressure cuffs placed on arms and tights. They also did the same training but without blood flow restriction. Endothelial parameters and angiogenesis biomarkers were evaluated before and up to 20 min after exercise. Both types of exercise increased Flow-Mediated Dilatation (FMD) but elevation after BFRE was more significant compared to the controls. The stiffness index decreased only after BFRE, while the reflection index decreased significantly after both types of exercise but was higher after BFRE. Platelet endothelial cell adhesion molecule (PECAM-1) and vascular endothelial growth factor receptor 2 (VEGFR-2) concentrations were increased by both exercise types but elevations were higher after BFRE compared to the controls. Only BFRE elevated the mean serum CD34 protein concentration. Based on these results, we can assume that low-resistance BFR exercise stimulates angiogenesis and improves endothelial functions more significantly compared to the same training performed without blood flow restriction.

Arterial stiffness indices in children and adolescents with type 1 diabetes mellitus: A meta-analysis

AIMS

Cardiovascular disease (CVD) represents the most frequent cause of morbidity and mortality among patients with type 1 diabetes mellitus (T1DM). Our aim was to review the evidence and conduct a meta-analysis assessing measures of arterial stiffness by pulse wave velocity (PWV) and augmentation index (AIx) in children and adolescents with T1DM compared to healthy controls.

METHODS

PubMed and the Cochrane Library were searched for relevant studies published up to 10 May 2021.

RESULTS

Twenty-one studies were finally included in the meta-analysis. The T1DM group had significantly higher carotid to femoral PWV levels than that of the control group (mean difference [d]: 0.53 CI: 0.35-0.71, P < 0.00001) but with a fair heterogeneity (I 2:73%). By omitting one study with marked heterogeneity, mean difference in cfPWV remained significantly increased in the T1DM group compared to the control group (mean difference [d]: 0.37 CI: 0.27-0.48, P < 0.00001) but with improved heterogeneity (I2 = 26%). Regarding Aix, the T1DM group had a significantly higher AI@75 index than that of the control group (mean difference [d]: 0.28 CI: 0.17-0.39, P < 0.00001) and with no heterogeneity (I 2 = 8%).

CONCLUSIONS

Youths with T1DM show increased arterial stiffness, either as increased carotid-femoral pulse wave velocity or increased augmentation index, early in their course of life compared to healthy controls.

PROSPERO REGISTRATION NUMBER

CRD42021253236.

Relationship between lipid parameters and vascular mechanical characteristics among a normotensive population without diabetes mellitus residing at the Qinghai-Tibet plateau: a cross-sectional study

Background

There is limited evidence regarding the relationship between lipid parameters and vascular mechanical characteristics in the normotensive population without diabetes mellitus. The aim of this study was to identify an association between lipid parameters and changes in vascular mechanical characteristics between men and women, and in women before and after menopause.

Methods

Six hundred-seventy patients who underwent vascular functional testing and who fulfilled the inclusion and exclusion criteria were enrolled in our cross-sectional study. All participants were from the Qinghai–Tibet Plateau (Luhuo County, Ganzi Tibetan Autonomous Prefecture, Sichuan Province, China; mean altitude: 3860 m). Trained clinical physicians assessed brachial-ankle pulse wave velocity (Ba-PWV) and augmentation index adjusted to a 75-beats-per-minute heart rate (AIx@75). To investigate the relationship between lipid parameters and vascular mechanical characteristics in different sexes and menstrual stages, partial correlation analysis and multiple linear regression were used.

Results

The 670 participants comprised 445 women (103 post-menopausal). Mean Ba-PWV and AIx@75 were 1315.56 ± 243.41 cm/s and 25.07% ± 15.84%, respectively. Men had greater Ba-PWV values compared with women (1341.61 ± 244.28 vs 1302.39 ± 242.17 cm/s, respectively; P < 0.05), while AIx@75 values were higher in women compared with men (27.83% ± 15.85% vs 19.64% ± 14.40%, respectively; p < 0.001). In the partial correlation analysis adjusted for age, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (HDL-C) were associated with Ba-PWV in both men and women (p < 0.05); however, the magnitude was larger in men. Statistical significance was not seen for AIx@75 among both men and women. Multiple linear regression analysis revealed that TC (β = 0.165, p = 0.024) and non-HDL-C (β = 0.151, p = 0.042) remained independent predictors of change in Ba-PWV in men after adjusting for age, mean arterial pressure, waist circumference, hemoglobin, platelet count, fasting blood glucose, estimated glomerular filtration rate, and uric acid. After adjusting for traditional cardiovascular risk factors, pre-menopausal women had a similar association to that of men between LDL-C (β = 0.126, p = 0.030), non-HDL-C (β = 0.144, p = 0.013), TC/HDL-C (β = 0.162, p = 0.005), LDL-C/HDL-C (β = 0.142, p = 0.013) and Ba-PWV; however, post-menopausal women had no association between the lipid parameters and vascular function.

Conclusions

Overall, TC and non-HDL-C were independent associated factors for vascular compliance alterations evaluated through Ba-PWV in normotensive men. In pre-menopausal women, LDL-C, non-HDL-C, TC/HDL-C and LDL-C/HDL-C were independent associated factors for vascular compliance alterations. After controlling for traditional risk factors, lipid profiles were not associated with these metrics for AIx@75, which can measure the amplification of reflex flow, because of the high number of confounding factors that do not genuinely reflect changes in vascular characteristics. Lipid factors did not appear to be linked to vascular function in post-menopausal women.

Higher habitual dietary flavonoid intake associates with lower central blood pressure and arterial stiffness in healthy older adults

Flavonoids have shown anti-hypertensive and anti-atherosclerotic properties: the impact of habitual flavonoid intake on vascular function, central haemodynamics and arterial stiffness may be important. We investigated the relationship between habitual flavonoid consumption and measures of central blood pressure and arterial stiffness. We performed cross-sectional analysis of 381 non-smoking healthy older adults (mean age 66·0 (sd 4·1) years; BMI, 26·4 (sd 4·41) kg/m2; 41 % male) recruited as part of the Australian Research Council Longevity Intervention study. Flavonoid intake (i.e. flavonols, flavones, flavanones, anthocyanins, isoflavones, flavan-3-ol monomers, proanthocyanidins, theaflavins/thearubigins and total consumption) was estimated from FFQ using the US Department of Agriculture food composition databases. Measures of central haemodynamics and arterial stiffness included systolic blood pressure (cSBP), diastolic blood pressure (cDBP), mean arterial pressure (cMAP) and augmentation index (cAIx). After adjusting for demographic and lifestyle confounders, each sd/d higher intake of anthocyanins ((sd 44·3) mg/d) was associated with significantly lower cDBP (-1·56 mmHg, 95 % CI -2·65, -0·48) and cMAP (-1·62 mmHg, 95 % CI -2·82, -0·41). Similarly, each sd/d higher intake of flavanones ((sd 19·5) mg/d) was associated with ~1 % lower cAIx (-0·93 %, 95 % CI -1·77, -0·09). These associations remained significant after additional adjustment for (1) a dietary quality score and (2) other major nutrients that may affect blood pressure or arterial stiffness (i.e. Na, K, Ca, Mg, n-3, total protein and fibre). This study suggests a possible benefit of dietary anthocyanin and flavanone intake on central haemodynamics and arterial stiffness; these findings require corroboration in further research.

Vascular alterations among male elite athletes recovering from SARS-CoV-2 infection

SARS-CoV-2 may affect the cardiovascular system and vascular impairment has been reported in healthy young adults recovering from COVID-19. However, the impact of SARS-CoV-2 infection on the vascular function of elite athletes is unknown. We examined 30 healthy male elite athletes (age 25.8 ± 4.6 years) pre-season and at a 6-month follow-up (182 ± 10 days). Vascular function and central blood pressure were calculated using transfer function-based analysis of peripheral arterial waveforms obtained by oscillometry. We performed a two-way repeated-measures ANOVA on the biomarker data, with SARS-CoV-2 status as the between-groups factor and time as the within-groups factor. Subjects who tested positive for SARS-CoV-2 were studied 18 ± 4 days after their positive testing date at follow-up. Of 30 athletes, 15 tested positive for SARS-CoV-2 after the first examination and prior to the follow-up. None had severe COVID-19 or reported any persisting symptoms. The results of the two-way repeated measures ANOVA revealed that there was no significant main effect of COVID-19 on any of the investigated biomarkers. However, there was a significant interaction between the effects of SARS-CoV-2 exposure and time on augmentation index (Aix) (p = 0.006) and augmentation index normalized to a heart rate of 75 beats per minute (Aix@75), (p = 0.0018). The observation of an interaction effect on Aix and Aix@75 in the absence of any main effect indicates a cross-over interaction. Significant vascular alterations in male elite athletes recovering from COVID-19 were observed that suggest vascular impairment. Whether these alterations affect athletic performance should be evaluated in future studies.

Association of arterial stiffness and heart failure with preserved ejection fraction in the elderly population - results from the CARLA study

Arterial stiffness has been suspected as a cause of left ventricular diastolic dysfunction and may thereby contribute to the development of heart failure with preserved ejection fraction (HFpEF). However, this association is derived from a small number of studies and application of outdated criteria to diagnose HFpEF. This study aimed to investigate the association of arterial stiffness measured by the augmentation index (AIx) and criteria for diagnosing HFpEF according to the recommended HFA-PEFF score. Our analysis based on data from the first follow-up of the CARdiovascular Disease, Living and Ageing in Halle study. The current analysis included participants with available information about comorbidities and risk factors for HFpEF, parameters for calculation of the HFA-PEFF and noninvasive AIx estimated by applanation tonometry. The association of AIx and HFA-PEFF was investigated through descriptive and inductive statistics. A total of 767 participants were included in the analysis. AIx was associated with E/e', left ventricular wall thickness (LVWT), relative wall thickness, left ventricular mass index (LVMI) and NT-proBNP but not with e' or left atrial volume index. However, after adjustment for confounders, only LVMI and LVWT remained associated with AIx. Males with a high AIx had a 3.2-fold higher likelihood of HFpEF than those with a low AIx. In contrast, that association was not present in females. In summary, AIx is associated with the morphological domain of the HFA-PEFF score represented by LVMI and LVWT. Higher values of AIx are associated with a higher likelihood for HFpEF in elderly males but not in females.

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.

Aortic haemodynamics: the effects of habitual endurance exercise, age and muscle sympathetic vasomotor outflow in healthy men

PURPOSE

We determined the effect of habitual endurance exercise and age on aortic pulse wave velocity (aPWV), augmentation pressure (AP) and systolic blood pressure (aSBP), with statistical adjustments of aPWV and AP for heart rate and aortic mean arterial pressure, when appropriate. Furthermore, we assessed whether muscle sympathetic nerve activity (MSNA) correlates with AP in young and middle-aged men.

METHODS

Aortic PWV, AP, aortic blood pressure (applanation tonometry; SphygmoCor) and MSNA (peroneal microneurography) were recorded in 46 normotensive men who were either young or middle-aged and endurance-trained runners or recreationally active nonrunners (10 nonrunners and 13 runners within each age-group). Between-group differences and relationships between variables were assessed via ANOVA/ANCOVA and Pearson product-moment correlation coefficients, respectively.

RESULTS

Adjusted aPWV and adjusted AP were similar between runners and nonrunners in both age groups (all, P > 0.05), but higher with age (all, P < 0.001), with a greater effect size for the age-related difference in AP in runners (Hedges' g, 3.6 vs 2.6). aSBP was lower in young (P = 0.009; g = 2.6), but not middle-aged (P = 0.341; g = 1.1), runners compared to nonrunners. MSNA burst frequency did not correlate with AP in either age group (young: r = 0.00, P = 0.994; middle-aged: r = - 0.11, P = 0.604).

CONCLUSION

There is an age-dependent effect of habitual exercise on aortic haemodynamics, with lower aSBP in young runners compared to nonrunners only. Statistical adjustment of aPWV and AP markedly influenced the outcomes of this study, highlighting the importance of performing these analyses. Further, peripheral sympathetic vasomotor outflow and AP were not correlated in young or middle-aged normotensive men.

Arterial stiffness measurements in pregnancy as a predictive tool for hypertensive disorders of pregnancy and preeclampsia: Protocol for a systematic review and meta-analysis

Hypertensive disorders of pregnancy (HDPs) are a leading cause of maternal morbidity and mortality worldwide. Unfortunately, accurate early clinical screening methods for the development of these disorders are lacking. Arterial stiffness (AS) is an important hemodynamic indicator of vascular health that has shown promising results for the prediction of HDP onset. Past systematic reviews in the field have reported an increase in AS indices in women who develop HDPs and have highlighted the potential of AS measurements as a predictive tool early in pregnancy. The most recent systematic review, including papers up to 2015, assessed the differences in AS parameters between women with and without pregnancy complications. Since then, there has been a substantial influx of published research on the topic and a growing interest in the incorporation of AS measurements into clinical practice. Thus, we propose a systematic review and meta-analysis that is more inclusive to all HDP subsets and various hemodynamic indices of vascular health to provide a comprehensive overview of the current state of evidence. Specifically, we aim to evaluate these measures in women who develop HDPs compared to normotensive pregnancies to determine which measures are most associated with and/or can predict the development of HDPs. Major databases (Medline, Embase, The Cochrane Library, Web of Science, PubMed, and CINAHL), grey literature (Google Scholar) and clinical trials (clinicaltrials.gov) will be searched to identify studies that report AS and hemodynamic measurements in pregnant women with and without HDPs. No restrictions will be made on study type or year. Articles will be independently evaluated by three authors to determine eligibility based on inclusion and exclusion criteria. Methodological quality of included studies will be assessed. Pooled analyses will be conducted using a random-effects model. Publication bias and between-study heterogeneity will also be assessed. Sources of heterogeneity will be explored by sensitivity, subgroup, and/or meta-regression analyses. Results from this study will be shared through scientific conferences and publications in scientific journals. The analysis of potential AS and hemodynamic markers for HDP onset will help inform the development of screening guidelines and clinically relevant cut-off values of AS and hemodynamic markers for HDP risk, guiding future research. There are no applicable ethical considerations to the writing of this protocol.

Endothelial Dysfunction in Childhood Cancer Survivors: A Narrative Review

Assessment of endothelial dysfunction in cancer survivors may have a role in the early identification of non-communicable diseases and cardiovascular late effects. Oncological therapies may impair endothelial function. Therefore, in patients such as childhood cancer survivors who could benefit from early cardioprotective pharmacological interventions, it is essential to monitor endothelial function, even if the optimal methodology for investigating the multifaceted aspects of endothelial dysfunction is still under debate. Biochemical markers, as well as invasive and non-invasive tools with and without pharmacological stimuli have been studied. Human clinical studies that have examined lifestyle or cancer treatment protocols have yielded evidence showing the involvement of lipid and lipoprotein levels, glycemic control, blood pressure, adiposity, inflammation, and oxidative stress markers on the state of endothelial health and its role as an early indicator of cardiometabolic risk. However, with regards to pharmacological interventions, cautious interpretation of the result attained whilst monitoring the endothelial function is warranted due to methodological limitations and substantial heterogeneity of the results reported in the published studies. In this narrative review, an overview of evidence from human clinical trials examining the effects of cancer therapies on endothelial disease is provided together with a discussion of endothelial function assessment using the different non-invasive techniques available for researchers and clinicians, in recent years.

Pulse sharpness as a quantitative index of vascular aging

The aim of this study was to develop a robust algorithm to quantify pulse sharpness that can complement the limitations of radial augmentation index (rAIx) and explore the role of this quantitative sharpness index in reflecting vascular aging or arterial stiffness. The pulse sharpness index (PSI) was developed by combining the end point angle and virtual height, and 528 radial pulses were analyzed. The PSI could be uniformly applied to various waveform morphologies, even those with no or vague tidal waves, unlike the rAIx. Significant sex differences were identified in the rAIx and PSI (P < 0.01 for both), and significant age-dependent decreases in the PSI were observed (P < 0.01). In addition, the PSI and age were correlated (r = - 0.550) at least as strong as the rAIx and age (r = 0.532), and the PSI had a significant negative correlation with arterial stiffness (r = - 0.700). Furthermore, the multiple linear regression model for arterial stiffness using the PSI, age, sex and heart rate showed the excellent performance (cross-validated R2 = 0.701), and the PSI was found to have the greatest influence on arterial stiffness. This study confirmed that the PSI could be a quantitative index of vascular aging and has potential for use in inferring arterial stiffness with an advantage over the rAIx.

Degree of arterial stiffness is comparable across inflammatory joint disease entities

Objectives: Inflammatory joint disease (IJD) is associated with an increased risk of developing cardiovascular disease (CVD). Arterial stiffness is both a risk factor and a surrogate marker for CVD. This study aims to compare arterial stiffness across patients with rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis, and, by extension, to explore the relationship between arterial stiffness and the estimated CVD risk by the Systematic COronary Risk Evaluation (SCORE) algorithm.Method: During the study period, from April 2017 to June 2018, 196 patients with IJD visited the Preventive Cardio-Rheuma Clinic in Oslo, Norway. A CVD risk stratification was performed, including the assessment of traditional risk factors and the measurement of arterial stiffness.Results: Thirty-six patients (18.4%) had elevated aortic pulse wave velocity (aPWV) (≥ 10 m/s). After adjustment for age and heart rate, arterial stiffness was comparable across the IJD entities (p = 0.69). Associated factors, revealed by regression analysis, were age, blood pressure, heart rate, presence of carotid plaques, establis hed CVD, non-steroidal anti-inflammatory drugs, and statin use. Furthermore, aPWV was positively correlated with estimated CVD risk (r = 0.7, p < 0.001) and patients with a very high predicted CVD risk (SCORE ≥ 10%) had significantly higher aPWV than patients at lower CVD risk (9.2 vs 7.5 m/s, p < 0.001).Conclusion: The degree of arterial stiffness was comparable across the IJD entities and was highly associated with the estimated CVD risk. Our findings support the need for an increased focus on prevention of CVD in all patients with IJD.

Augmentation Index Predicts the Sweat Volume in Young Runners

Sweating during exercise is regulated by objective parameters, body weight, and endothelial function, among other factors. However, the relationship between vascular arterial stiffness and sweat volume in young adults remains unclear. This study aimed to identify hemodynamic parameters before exercise that can predict sweat volume during exercise, and post-exercise parameters that can be predicted by the sweat volume. Eighty-nine young healthy subjects (aged 21.9 ± 1.7 years, 51 males) were recruited to each perform a 3-km run on a treadmill. Demographic and anthropometric data were collected and hemodynamic data were obtained, including heart rate, blood pressure and pulse wave analysis using non-invasive tonometry. Sweat volume was defined as pre-exercise body weight minus post-exercise body weight. Post-exercise hemodynamic parameters were also collected. Sweat volume was significantly associated with gender, body surface area (BSA) (b = 0.288, p = 0.010), peripheral systolic blood pressure (SBP), peripheral and central pulse pressure (PP), and was inversely associated with augmentation index at an HR of 75 beats/min (AIx@HR75) (b = -0.005, p = 0.019) and ejection duration. While BSA appeared to predict central PP (B = 19.271, p ≤ 0.001), central PP plus AIx@HR75 further predicted sweat volume (B = 0.008, p = 0.025; B = -0.009, p = 0.003 respectively). Sweat volume was associated with peripheral SBP change (B = -17.560, p = 0.031). Sweat volume during a 3-km run appears to be influenced by hemodynamic parameters, including vascular arterial stiffness and central pulse pressure. Results of the present study suggest that vascular arterial stiffness likely regulates sweat volume during exercise.

Effects of cycling bouts performed with different intensities and amounts of energy expended on central pressure and pulse wave reflection in normotensive and hypertensive men

OBJECTIVE

This study investigated pulse wave analysis in normotensive and hypertensive men after cycling bouts with different intensities and amounts of energy expended.

METHODS

Twenty-four men were assigned into normotensive (n = 14; age: 40.7 ± 2.8 years; 24-h ambulatory SBP/DBP:121 ± 2/74 ± 1 mmHg) and hypertensive (n = 10; age: 39.2 ± 2.3 years; 24-h ambulatory SBP/DBP:139 ± 3/86 ± 2 mmHg) groups. Participants undertook a maximal cardiopulmonary exercise test, a nonexercise control session (CTL) and three cycling bouts [two prolonged bouts expending 300 kcal at 50% (i.e. P-MOD) and 70% (i.e. P-VIG) oxygen uptake reserve (VO2R) and one short bout expending 150 kcal at 50% VO2R (i.e. S-MOD)] performed in a randomized order. Central SBP (cSBP), pulse pressure (cPP), augmentation pressure, augmentation index (AIx), heart rate (HR) and AIx adjusted for HR (AIx@75) were determined 10 min before, and 30- and 70-min postintervention.

RESULTS

Compared to CTL, only the P-VIG changed the cSBP [70-min (Δ -11.7 mmHg)], cPP [70-min (Δ:-7.4 mmHg)], augmentation pressure [30-min (Δ:-5.7 mmHg); 70-min (Δ:-7.3 mmHg)], AIx [30-min (Δ:-15.3 %); 70-min (Δ:-16.4 %)], AIx@75 [30-min (Δ:-12.8 %); 70-min (Δ:-13.9 %)] and HR [70-min (Δ: 9.9 bpm)] in the hypertensive group. However, all exercise bouts mitigated the increased cSBP responses post-CTL in the hypertensive group.

CONCLUSION

The present study provides evidence that vigorous-intensity aerobic exercise reduces acute central pressure and pulse wave reflection in hypertensive men.

Phospholemman Phosphorylation Regulates Vascular Tone, Blood Pressure, and Hypertension in Mice and Humans

BACKGROUND

Although it has long been recognized that smooth muscle Na/K ATPase modulates vascular tone and blood pressure (BP), the role of its accessory protein phospholemman has not been characterized. The aim of this study was to test the hypothesis that phospholemman phosphorylation regulates vascular tone in vitro and that this mechanism plays an important role in modulation of vascular function and BP in experimental models in vivo and in humans.

METHODS

In mouse studies, phospholemman knock-in mice (PLM3SA; phospholemman [FXYD1] in which the 3 phosphorylation sites on serines 63, 68, and 69 are mutated to alanines), in which phospholemman is rendered unphosphorylatable, were used to assess the role of phospholemman phosphorylation in vitro in aortic and mesenteric vessels using wire myography and membrane potential measurements. In vivo BP and regional blood flow were assessed using Doppler flow and telemetry in young (14-16 weeks) and old (57-60 weeks) wild-type and transgenic mice. In human studies, we searched human genomic databases for mutations in phospholemman in the region of the phosphorylation sites and performed analyses within 2 human data cohorts (UK Biobank and GoDARTS [Genetics of Diabetes Audit and Research in Tayside]) to assess the impact of an identified single nucleotide polymorphism on BP. This single nucleotide polymorphism was expressed in human embryonic kidney cells, and its effect on phospholemman phosphorylation was determined using Western blotting.

RESULTS

Phospholemman phosphorylation at Ser63 and Ser68 limited vascular constriction in response to phenylephrine. This effect was blocked by ouabain. Prevention of phospholemman phosphorylation in the PLM3SA mouse profoundly enhanced vascular responses to phenylephrine both in vitro and in vivo. In aging wild-type mice, phospholemman was hypophosphorylated, and this correlated with the development of aging-induced essential hypertension. In humans, we identified a nonsynonymous coding variant, single nucleotide polymorphism rs61753924, which causes the substitution R70C in phospholemman. In human embryonic kidney cells, the R70C mutation prevented phospholemman phosphorylation at Ser68. This variant's rare allele is significantly associated with increased BP in middle-aged men.

CONCLUSIONS

These studies demonstrate the importance of phospholemman phosphorylation in the regulation of vascular tone and BP and suggest a novel mechanism, and therapeutic target, for aging-induced essential hypertension in humans.

Effects of aerobic, resistance and concurrent exercise on pulse wave reflection and autonomic modulation in men with elevated blood pressure

The acute effects of exercise modes on pulse wave reflection (PWR) and their relationship with autonomic control remain undefined, particularly in individuals with elevated blood pressure (BP). We compared PWR and autonomic modulation after acute aerobic (AE), resistance (RE), and concurrent exercise (CE) in 15 men with stage-1 hypertension (mean ± SE: 34.7 ± 2.5 years, 28.4 ± 0.6 kg/m², 133 ± 1/82 ± 2 mmHg). Participants underwent AE, RE, and CE on different days in counterbalanced order. Applanation tonometry and heart rate variability assessments were performed before and 30-min postexercise. Aortic pressure decreased after AE (− 2.4 ± 0.7 mmHg; P = 0.01), RE (− 2.2 ± 0.6 mmHg; P = 0.03), and CE (− 3.1 ± 0.5 mmHg; P = 0.003). Augmentation index remained stable after RE, but lowered after AE (− 5.1 ± 1.7%; P = 0.03) and CE (− 7.6 ± 2.4% P = 0.002). Systolic BP reduction occurred after CE (− 5.3 ± 1.9 mmHg). RR-intervals and parasympathetic modulation lowered after all conditions (~ 30–40%; P < 0.05), while the sympathovagal balance increased after RE (1.2 ± 0.3–1.3 ± 0.3 n.u., P < 0.05). Changes in PWR correlated inversely with sympathetic and directly with vagal modulation in CE. In conclusion, AE, RE, and CE lowered central aortic pressure, but only AE and CE reduced PWR. Overall, those reductions related to decreased parasympathetic and increased sympathetic outflows. Autonomic fluctuations seemed to represent more a consequence than a cause of reduced PWR.

Predictors and reference equations for augmentation index, an arterial stiffness marker, in healthy children and adolescents

OBJECTIVES

To investigate predictors and propose reference equations for the augmentation index normalized to 75 bpm heart rate (AIx@75) in healthy children and adolescents.

METHODS

This was a cross-sectional, observational study involving 134 healthy children and adolescents aged 9 to 19 years old. Participants were categorized into child (n=53) and adolescent (n=81) groups, as well as into male (n=69) and female (n=65) groups. We evaluated AIx@75, vascular and hemodynamic parameters, anthropometric data, physical activity profile, and quality of life (Peds-QL4.0; physical, emotional, social and school domains).

RESULTS

The predictors of AIx@75 in the whole sample were age, peripheral diastolic blood pressure (pDBP), mean arterial pressure, pulse pressure amplification (PPA), systolic volume (SV), cardiac index (CI), and pulse wave velocity (PWV; R2=80.47%). In the male group, the predictors of AIx@75 were SV, CI, total vascular resistence (TVR), and PWV (R2=78.56%), while in the female group, they were pDBP, PPA, SV, and PWV (R2=82.45%). In the children, they were pDBP, PPA, SV, and PWV (R2=79.17%), while in the adolescents, they were body mass index, pDBP, PPA, SV, TVR, and PWV (R2=81.57%).

CONCLUSION

In the present study, we used a representative sample from Belo Horizonte to establish normality values of AIx@75. We also identified, for the first time, independent predictors of AIx@75 in healthy children and adolescents categorized by sex and age. Determining AIx@75 reference equations may facilitate the early diagnosis of preclinical atherosclerosis and allow an objective measure of the vascular effects of therapeutic interventions aimed at modifying cardiovascular risk factors.

Evaluation of arterial stiffness in cardiac surgical patients using applanation tonometry

Context:

Applanation tonometry enables the noninvasive analysis of arterial pressure wave morphology. Applanation tonometry provides the augmentation index (AIx, %), an index of arterial stiffness that partially reflects arterial-ventricular (A-V) coupling. In addition, applanation tonometry provides the dP/dt (rate of intraventricular pressure variation over time), which reflects myocardial contractility, and the sub-endocardial viability ratio (SEVR, %), which is an indicator of myocardial oxygen supply and demand. There are no data on how cardiac surgery can modify these tonometry-derived indexes.

Aim:

The aim was to assess changes in AIx, dP/dt, and SEVR in patients undergoing cardiac surgery.

Subjects and Methods:

This observational study was conducted at the University Hospital of Siena. We studied 32 patients before cardiac surgery in intensive care unit (ICU) on admission and at ICU discharge. We measured AIx, dP/dt, and SEVR using applanation tonometry (SphygmoCor). Changes in variables over time were evaluated by analysis of variance for repeated measurements.

Results:

AIx decreased significantly from T1 [28.8%, interquartile range (IQR) 21.6–36.6%] to T2 (16.2% IQR 8.1–22.4%) and T3 (14.5% IQR 7.9–23.6%) (P = 0.01). dP/dt increased significantly from T1 (635 mmHg/ms, IQR 534–756 mmHg/ms) to T3 (751 mmHg/ms, IQR 651–1013 mmHg/ms; P = 0.03). The SEVR was lower at T2 than at T1, but returned toward T1 values by T3.

Conclusions:

Cardiac surgery was associated with an improvement in arterial stiffness, A-V coupling, and myocardial contractility as assessed using applanation tonometry. The results suggest, however, a transient imbalance between myocardial oxygen supply and demand in the immediate postoperative period.

Increased aortic augmentation index is associated with reduced exercise capacity after heart transplantation

OBJECTIVE

Exercise capacity is often reduced after heart transplantation. We aimed to investigate the association between aortic stiffness and exercise capacity after heart transplantation.

METHODS

We retrospectively analyzed the data of patients who underwent a cardiopulmonary exercise test and central hemodynamic measurements over 1 year following heart transplantation, from Janary 2011 to June 2018.

RESULTS

A total of 54 patients (mean age, 49 years; 72% men) were analyzed. The median peak oxygen uptake level was 21.1 ml/kg per min at a median time of 13 months after heart transplantation. In univariate linear regression, recipient age, pulmonary arterial pressure, pulmonary capillary wedge pressure, hemoglobin level, estimated glomerular filtration rate, aortic augmentation index, and pulse wave velocity were significant predictors for peak oxygen uptake level. After adjustment for other confounding variables, heart rate-corrected aortic augmentation index was a significant predictor for peak oxygen uptake (β = -0.141, 95% confidence interval, -0.263 to -0.058, P = 0.003).

CONCLUSION

In the present study, increased aortic augmentation index was associated with reduced exercise capacity after heart transplantation. Therefore, this simple measurement of aortic stiffness should be periodically used for the evaluation of exercise capacity after heart transplantation.

Longitudinal Effects of Cigarette Smoking and Smoking Cessation on Aortic Wave Reflections, Pulse Wave Velocity, and Carotid Artery Distensibility

Background We evaluated the effects of smoking and smoking cessation on aortic wave reflections (augmentation index), aortic pulse wave velocity, and carotid artery distensibility and stiffness (distensibility coefficient, Young's elastic modulus). Methods and Results Current smokers underwent carotid, radial, and femoral artery tonometry and carotid ultrasound at baseline and 3 years after a quit attempt. Baseline associations of smoking heaviness markers (exhaled carbon monoxide and cigarettes smoked/d) and effects of smoking cessation at year 3 on changes in arterial measures were assessed using multivariable linear regression models. The 1417 smokers (54% female) were mean (SD) 49.3 (11.6) years old and smoked 17.2 (8.3) cigarettes/d (exhaled carbon monoxide 14.7 [8.2] parts per million). Arterial measures were associated more strongly with age, blood pressure (BP), and waist circumference than with smoking heaviness markers. Augmentation index was associated independently with carbon monoxide (P=0.004). Pulse wave velocity, distensibility coefficient, and Young's elastic modulus had small, inconsistent associations with smoking heaviness markers. At year 3, augmentation index improved with smoking cessation (P=0.006) despite more weight gain (2.54 vs 0.36 kg, P<0.001) and insulin resistance (P=0.001) among abstainers, but distensibility coefficient decreased (P=0.004). Changes in arterial measures were related more strongly to changes in BP than smoking cessation. Conclusions Arterial wave reflection and stiffness measures were associated more strongly with age, BP, and waist circumference than smoking heaviness. Smoking cessation was associated with weight gain and increased insulin resistance. Changes in arterial measures were predicted by changes in BP, highlighting the need to address weight gain and BP changes during a quit attempt.

Impact of Red Beetroot Juice on Vascular Endothelial Function and Cardiometabolic Responses to a High-Fat Meal in Middle-Aged/Older Adults with Overweight and Obesity: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

BACKGROUND

High-fat meal (HFM) consumption may induce transient postprandial atherogenic responses, including impairment of vascular endothelial function, in individuals with overweight/obesity. Red beetroot juice (RBJ) may modulate endothelial function and other measures of cardiometabolic health.

OBJECTIVE

This study investigated the impact of acute and chronic RBJ consumption, including nitrate-dependent and -independent effects, on postprandial endothelial function and other cardiometabolic responses to a HFM.

METHODS

Fifteen men and postmenopausal women with overweight/obesity were enrolled in this randomized, double-blind, placebo-controlled, 4-period, crossover clinical trial. Following an overnight fast, participants underwent baseline assessment of endothelial function (reactive hyperemia index; RHI) and hemodynamics, and biological sample collection. In random order, participants consumed 70 mL (acute visit) of: 1) RBJ, 2) nitrate-free RBJ (NF-RBJ), 3) placebo + nitrate (PBO + NIT), or 4) placebo (PBO), followed by a HFM. RHI was remeasured 4 h post-HFM, and hemodynamic assessment and biological sample collection were performed 1, 2, and 4 h post-HFM consumption. Participants consumed treatments daily for 4 wk (chronic visit), and assessments were repeated before/after the HFM (without consuming treatments).

RESULTS

HFM consumption did not induce significant impairment of postprandial RHI. No significant differences in RHI were detected across treatment groups following acute or chronic exposure, despite increases in circulating nitrate/nitrite (NOx) concentrations in the RBJ and PBO + NIT groups compared with PBO and NF-RBJ (P < 0.0001 for all time points at the acute visit; P < 0.05 for all time points at the chronic visit). Although the HFM led to significant alterations in several secondary outcomes, there were no consistent treatment effects on postprandial cardiometabolic responses.

CONCLUSIONS

HFM consumption did not impair postprandial endothelial function in this population, and RBJ exposure did not alter postprandial endothelial function or other outcomes despite increasing NOx concentrations. This trial is registered at clinicaltrials.gov as NCT02949115.

Augmentation index in the assessment of wave reflections and systolic loading

BACKGROUND

Augmentation index (AI_x) is used to quantify the augmented systolic aortic pressure that impedes ventricular ejection. Its use as an index of wave reflections is questionable. We hypothesize that AI_x is quantitatively different from the reflection coefficient under varied physiological conditions.

METHODS

42 datasets of aortic pressure and flow waveforms were obtained during induced hypertension (methoxamine infusion) and vasodilation (nitroprusside infusion) in our mongrel dog experiments (n = 5) and from Mendeley data during various interventions (vasoconstrictors, vasodilators, pacing, stimulation, hemorrhage and hemodilution). Wave reflections and principal components of reflection coefficients were computed for comparison to AI_x and heart rate normalized AI_x. RESULTS: Principal reflection coefficient, Γ₁, increased in hypertension and decreased in vasodilation, hemorrhage and hemodilution. AI_x followed the trend in many cases but was consistently lower than Γ₁ in almost all the subjects. The Bland-Altman analysis also showed that both AI_x and normalized AI_x underestimated Γ₁. The relationship between augmentation index and reflection coefficient was explained by a linear regression model (r² = 0.23, p < 0.01) in which AI_x followed directional changes in Γ₁ and the normalization of AI_x resulted in a linear model that explained less variation in the relationship between AI_x and Γ₁.

CONCLUSION

AI_x is a reasonable clinical trend indicator, albeit not an accurate surrogate measure of the amount of wave reflections.

Proximal pressure reducing effect of wave reflection in the pulmonary circulation disappear in obstructive disease: insight from a rabbit model

Locating the site of increased resistance within the vascular tree in pulmonary arterial hypertension could assist in both patient diagnosis and tailoring treatment. Wave intensity analysis (WIA) is a wave analysis method that may be capable of localizing the major site of reflection within a vascular system. We investigated the contribution of WIA to the analysis of the pulmonary circulation in a rabbit model with animals subjected to variable occlusive pulmonary disease. Animals were embolized with different sized microspheres for 6 wk ( n = 10) or underwent pulmonary artery (PA) ligation for 6 wk ( n = 3). These animals were compared with a control group ( n = 6) and acutely embolized animals ( n = 4). WIA was performed and compared with impedance-based methods to analyze wave reflections. The control group showed a relatively high extent of reflected waves (15.7 ± 10.6%); reflections had a net effect of pressure reduction during systole, suggesting an open-end reflector. The pattern of wave reflection was not different in the group with partial PA ligation (12.4 ± 4.1%). In the chronically embolized group, wave reflection was not observed (3.6 ± 1.5%). In the acute embolization group, wave reflection was more prominent (37.3 ± 12.6%), with the appearance of a novel wave increasing pressure, suggesting the appearance of a closed-end reflector. Wave reflections of an open-end type are present in the normal rabbit pulmonary circulation. However, the pattern and nature of reflections vary according to the extent of pulmonary vascular occlusion.

NEW & NOTEWORTHY The study proposes an original framework of a complementary analysis of wave reflections in the time domain and in the frequency domain. The methodology was used in the pulmonary circulation with different forms of chronic obstructions. The results suggest that the pulmonary vascular tree generates a reflection pattern that could actually assist the heart during ejection, and chronic obstruction significantly modifies the pattern.

Relationships between indicators of cardiovascular disease and intensity of oil and natural gas activity in Northeastern Colorado

BACKGROUND

Oil and natural gas (O&G) extraction emits pollutants that are associated with cardiovascular disease, the leading cause of mortality in the United States.

OBJECTIVE

We evaluated associations between intensity of O&G activity and cardiovascular disease indicators.

METHODS

Between October 2015 and May 2016, we conducted a cross-sectional study of 97 adults living in Northeastern Colorado. For each participant, we collected 1-3 measurements of augmentation index, systolic and diastolic blood pressure (SBP and DBP), and plasma concentrations of interleukin (IL)- 1β, IL-6, IL-8 and tumor necrosis factor alpha (TNF-α). We modelled the intensity of O&G activity by weighting O&G well counts within 16 km of a participant's home by intensity and distance. We used linear models accounting for repeated measures within person to evaluate associations.

RESULTS

Adjusted mean augmentation index differed by 6.0% (95% CI: 0.6, 11.4%) and 5.1% (95%CI: -0.1, 10.4%) between high and medium, respectively, and low exposure tertiles. The greatest mean IL-1β, and α-TNF plasma concentrations were observed for participants in the highest exposure tertile. IL-6 and IL-8 results were consistent with a null result. For participants not taking prescription medications, the adjusted mean SBP differed by 6 and 1 mm Hg (95% CIs: 0.1, 13 mm Hg and -6, 8 mm Hg) between the high and medium, respectively, and low exposure tertiles. DBP results were similar. For participants taking prescription medications, SBP and DBP results were consistent with a null result.

CONCLUSIONS

Despite limitations, our results support associations between O&G activity and augmentation index, SBP, DBP, IL-1β, and TNF-α. Our study was not able to elucidate possible mechanisms or environmental stressors, such as air pollution and noise.

The impact of upper-limb position on estimated central blood pressure waveforms

Pulse wave analysis (PWA) utilizes arm blood pressure (BP) waveforms to estimate aortic waveforms. The accuracy of central BP waveform estimation may be influenced by assessment site local haemodynamics. This study investigated whether local haemodynamic changes, induced via arm tilting ±30° relative to heart level, affect estimated central systolic BP (cSBP) and arterial wave reflection (central augmentation index, cAIx; aortic backward pressure wave, Pb). In 20 healthy adults (26.7 years [SD 5.2], 10 F) brachial BP waveforms were simultaneously recorded on experimental and control arms. The experimental arm was randomly repositioned three times (heart level, -30° heart level, +30° heart level), while the control arm remained fixed at heart level. For the experimental arm, arm repositioning resulted in a large (partial eta-squared > 0.14) effect size (ES) change in SBP (ES = 0.75, P < 0.001), cSBP (ES = 0.81, P < 0.001), and cAIx (ES = 0.75, P = 0.002), but not Pb (ES = 0.06, P = 0.38). In the control arm, cAIx (ES = 0.22, P = 0.013) but not SBP or cSBP significantly changed. Change in experimental arm cSBP was partially explained by brachial systolic blood velocity (P = 0.026) and mean diameter (P = 0.012), while change in cAIx was associated with brachial retrograde blood velocity (P = 0.020) and beta stiffness (P = 0.038). In conclusion, manipulation of assessment site local haemodynamics, including the blood velocity profile and local arterial stiffness, had a large effect on estimated cSBP and cAIx, but not on Pb. These findings do not invalidate PWA devices but do suggest that the accuracy of the estimated aortic pressure waveform is dependent on stable peripheral haemodynamics.

Oscillometric central blood pressure and central systolic loading in stroke patients: Short-term reproducibility and effects of posture and fasting state

BACKGROUND

This study examined the short-term reproducibility of non-invasive estimates of central and peripheral blood pressure and markers of central systolic loading (augmentation index [AIx; a measure of central systolic loading] and AIx75 [AIx standardised to 75 b·min-1 heart rate]) and the effect of posture and fasting state on these variables in patients with acute stroke.

METHODS

Twenty-two acute stroke patients (72 ± 10y) had blood pressure measured using the SphygmoCor XCEL in supine and seated postures and whilst fasted and non-fasted.

RESULTS

Acceptable short-term reproducibility (ICC >0.75) was reported for all peripheral and central variables in all conditions (ICC = 0.77-0.90) and for AIx and AIx75 in both fasted postures (ICC = 0.78-0.81). Food consumption significantly lowered all blood pressures (p <0.05; η2p = 0.20-0.55). The seated posture resulted in a significantly greater AIx than supine (p <0.05; η2p = 0.22). Fasting state had significant main effects on AIx and AIx75 (p <0.05; η2p = 0.14-0.22).

CONSLUSIONS

Oscillometric estimates of central blood pressure have high short-term reproducibility in different postures and fasting states but markers of systolic load should be assessed whilst fasted. Fasting state has a large effect on central and peripheral blood pressures and on measures of systolic loading. It is important for clinicians to be aware of optimal assessment conditions without this impacting on patient wellbeing.

TRIAL REGISTRATION

Clinical trial registry name: NCT02537652.

Hyperleptinemia is associated with the aortic augmentation index in kidney transplant recipients

OBJECTIVE

Increased circulating leptin, a marker of leptin resistance, is common in patients with obesity and is also an independent factor in prediction of cardiovascular disease. The aim of this study was to evaluate the relationship between fasting serum leptin levels and the aortic augmentation index (AIx) in kidney transplant recipients.

MATERIALS AND METHODS

Fasting blood samples were obtained from 70 kidney transplant recipients. The aortic AIx was measured using a validated tonometry system (SphygmoCor). Plasma leptin levels were measured using a commercial enzyme-linked immunosorbent assay kit.

RESULTS

Simple linear analysis of the aortic AIx in kidney transplant recipients showed that body fat mass (P = 0.002), diastolic blood pressure (DBP) (P = 0.020), logarithmically transformed triglycerides (P = 0.035), and leptin (P < 0.001) were positively correlated, while height (P = 0.004) and the glomerular filtration rate (P = 0.022) were negatively correlated with the aortic AIx in kidney transplant recipients. Forward stepwise linear regression analysis of the factors significantly associated with the aortic AIx showed that leptin (P < 0.001), DBP (P = 0.014), and body height (P = 0.036) were independent predictors of the aortic AIx in kidney transplant recipients.

CONCLUSION

These results suggest that the serum fasting leptin level is associated with the aortic AIx in kidney transplant recipients.

Reference Intervals of Central Aortic Blood Pressure and Augmentation Index Assessed with an Oscillometric Device in Healthy Children, Adolescents, and Young Adults from Argentina

Age-related reference intervals (RIs) of central (aortic) systolic blood pressure (cSBP) and augmentation index (cAIx) obtained from large healthy population are lacking in Argentina (South America). Aims. To analyze the existence of associations among cSBP and cAIx with demographic, anthropometric, and hemodynamic parameters and to generate percentile curves and RIs adjusted to each level of age and gender and/or body height. cSBP and cAIx were measured in 1038 healthy children, adolescents, and young adults. First, we evaluated if RIs for males and females were necessary using correlation and covariate analysis. Second, mean (M) and standard deviation (SD) age-related equations were obtained for cSBP and cAIx, using parametric regression methods based on fractional polynomials. Third, age specific percentiles curves were generated. Fourth, body height specific percentiles curves were generated using a similar procedure. The obtained equations (considering age as independent variable) for all subjects (cSBP^0.26 and (cAIx + 12.001)^0.5) were as follows: cSBP Mean = 3.0581 + 0.2189 log(Age) − 0.001044Age; cSBP SD = −0.03919 + 0.1535 log(Age) − 0.004564Age; cAIx mean = 9.5226 − 6.1599 log(Age) + 0.1450Age; cAIx SD = 1.3880 − 0.8468 log(Age) + 0.03212Age. This study, performed in Argentinean healthy children, adolescents, and young adults with ages of 5 to 22 years, provides the first RIs and percentile curves of cSBP and cAIx. Additionally, specific body height-related cAIx percentiles are reported for the analyzed population. The RIs and percentiles contribute to the knowledge of arterial dynamic evolution along the normal aging process and the interpretation of data obtained in clinical research and daily clinical practice.

Central Blood Pressure Responses to Dietary Sodium and Potassium Interventions

BACKGROUND

To explore how central hemodynamics respond to dietary sodium and potassium interventions, and whether the responses are associated with metabolic traits.

METHODS

We conducted a dietary intervention study including a 7-day low-sodium (51.3 mmol sodium/day) intervention, a 7-day high-sodium (307.8 mmol sodium/day) intervention, and a 7-day high-sodium with potassium supplementation (60.0 mmol potassium/day) intervention among 99 northern Chinese subjects aged 18-60 years. Five metabolic traits included abdominal obesity, high triglycerides, low HDL cholesterol, raised blood pressure (BP), and high glucose. Central hemodynamics were measured at baseline and during each intervention.

RESULTS

Central systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), and augmentation index (AIx@75) significantly decreased during low-sodium intervention, increased during high-sodium intervention, and then decreased during potassium supplementation. We observed potential linear trends toward significance of central SBP and PP responses to low-sodium intervention, and significant linear trends of responses to high-sodium intervention as the number of metabolic traits grows. For example, among participants with 0 or 1, 2 or 3, and 4 or 5 metabolic traits, central SBP responses to high-sodium intervention were 8.8 [95% confidence interval (5.8, 11.8)], 9.3 (7.1, 11.6), and 14.0 (11.6, 16.3) mmHg, respectively (P for trend = 0.009). Significant linear trends of central SBP and DBP responses to potassium supplementation were also observed.

CONCLUSIONS

Central BP and AIx@75 were lowered by sodium reduction and potassium supplementation, and elevated by sodium-loading. The responses of central BP were pronounced among individuals with metabolic traits clustering.

CLINICAL TRIALS REGISTRATION

Trial Number NCT00721721 (The current study is registered on ClinicalTrials.gov; https://clinicaltrials.gov).

Salbutamol-induced Decrease in Augmentation Index is Related to the Parallel Increase in Heart Rate

The change in augmentation index following salbutamol inhalation has been applied to evaluate endothelial function. We examined the contribution of salbutamol-induced increase in heart rate to the observed decrease in augmentation index. Haemodynamics were recorded using whole-body impedance cardiography and continuous pulse wave analysis from tonometric radial blood pressure. All subjects (n = 335, mean age 46, body mass index 26, 48% men) were without medications with cardiovascular influences. The effects of salbutamol inhalation (0.4 mg) versus the endothelium-independent agent nitroglycerin resoriblet (0.25 mg) were examined during passive head-up tilt, as the haemodynamic influences of these compounds depend on body position. Salbutamol decreased augmentation index by ~3-4% units in supine and upright positions. Although salbutamol moderately increased cardiac index (+4.5%) and decreased systemic vascular resistance (-8.5%), the significant haemodynamic explanatory factors for decreased augmentation index in multivariate analysis were increased supine heart rate, and increased upright heart rate and decreased ejection duration (p < 0.001 for all, r²  = 0.36-0.37). Sublingual nitroglycerin decreased supine and upright augmentation index by ~15% units and ~23% units, respectively. The haemodynamic explanatory factors for these changes in multivariate analysis were increased heart rate, reduced ejection duration and reduced systemic vascular resistance (p ≤ 0.021 for all, r²  = 0.22-0.34). In conclusion, the lowering influence of salbutamol on augmentation index may be largely explained by increased heart rate, suggesting that this effect may not predominantly reflect endothelial function.

Reliability of pulse waveform separation analysis responses to an orthostatic challenge

Cardiovascular autonomic nervous system function can be assessed using an orthostatic challenge to induce arterial wave reflection. While arterial reflection is typically estimated using a central augmentation index, a superior estimation can be obtained using pulse wave separation analysis to estimate the aortic backward pressure wave (Pb). However, to be of value in a clinical or research setting, an assessment tool must be precise (reliable). Therefore, this study sought to determine the measurement precision of Pb responses to a modified tilt-table test. Twenty healthy adults (26.4 year (SD 5.2), 24.7 kg/m² (SD 3.8), 55% female) were tested in a fasted state on three different mornings separated by a maximum of seven days. Pressure waveforms were recorded on the left arm, and aortic waveforms were generated using a generalized transfer function. Subsequently, a physiologic flow waveform was assumed to separate the aortic pressure wave into its forward and timing-independent backward (Pb) components. The criterion intra-class correlation coefficient of ≥0.75 was exceeded at baseline (0.79), following a 5-min tilt (0.75), and following a 5-min recovery from tilt (0.75). The standard error of measurement was 7%. These findings indicate that in a healthy cohort, the Pb response to an orthostatic challenge can be assessed with acceptable precision. The next step is to determine the sensitivity (validity) of this technique in identifying cardiovascular autonomic dysfunction in patient groups.

The effect of high altitude on central blood pressure and arterial stiffness

Central arterial systolic blood pressure (SBP) and arterial stiffness are known to be better predictors of adverse cardiovascular outcomes than brachial SBP. The effect of progressive high altitude (HA) on these parameters has not been examined. Ninety healthy adults were included. Central BP and the augmentation index (AI) were measured at the level of the brachial artery (Uscom BP⁺ device) at <200 m and at 3619, 4600 and 5140 m. The average age of the subjects (70% men) were 32.2±8.7 years. Compared with central arterial pressures, brachial SBP (+8.1±6.4 mm Hg; P<0.0001) and pulse pressure (+10.9±6.6 mm Hg; P<0.0001) were significantly higher and brachial diastolic BP was lower (-2.8±1.6 mm Hg; P<0.0001). Compared with <200 m, HA led to a significant increase in brachial and central SBP. Central SBP correlated with AI (r=0.50; 95% confidence interval (CI): 0.41-0.58; P<0.0001) and age (r=0.32; 95% CI: 21-0.41; P<0.001). AI positively correlated with age (r=0.39; P<0.001) and inversely with subject height (r=-0.22; P<0.0001), weight (r=-0.19; P=0.006) and heart rate (r=-0.49; P<0.0001). There was no relationship between acute mountain sickness scores (Lake Louis Scoring System (LLS)) and AI or central BP. The independent predictors of central SBP were male sex (coefficient, t=4.7; P<0.0001), age (t=3.6; P=0.004) and AI (t=7.5; P<0.0001; overall r²=0.40; P<0.0001). Subject height (t=2.4; P=0.02), age (7.4; P<0.0001) and heart rate (t=11.4; P<0.0001) were the only independent predictors of AI (overall r²=0.43; P<0.0001). Central BP and AI significantly increase at HA. This rise was influenced by subject-related factors and heart rate but not independently by altitude, LLS or SpO₂.

Controversies in the association of cardiorespiratory fitness and arterial stiffness in children and adolescents

The relationship between cardiorespiratory fitness and arterial compliance in children and adolescents remains controversial. The aim of this study was to assess this association with a quantitative approach. A total of 646 healthy children and adolescents (316 females, age 13.9±2.1 years) were cross-sectionally investigated in seven school settings in and around Munich for their cardiorespiratory fitness and demographic, anthropometric and hemodynamic parameters. Surrogates of arterial stiffness, such as pulse wave velocity (PWV), Augmentation Index normalized to a heart rate of 75 (AI@75), and peripheral and central systolic blood pressures were measured in a supine position using the oscillometric Mobil-O-Graph. Cardiopulmonary fitness was measured by 6-min indoor run tests. After correction for age, sex, body weight, body height, heart rate and mean arterial pressure, controversial findings were produced. PWV increased with higher cardiorespiratory fitness (Beta=0.173; P<0.001), which represented an unfavorable relationship, whereas AI@75 declined with higher cardiorespiratory fitness (Beta=-0.106; P=0.025). Therefore, in contrast to PWV, higher cardiorespiratory fitness seems beneficial for AI@75. The third surrogate of arterial stiffness, central systolic blood pressure, showed no association with cardiorespiratory fitness (Beta=0.066; P=0.052). These controversial outcomes remain almost unchanged when the boys and girls were analyzed separately. Different surrogates of arterial stiffness have different relationships with cardiorespiratory fitness in children and adolescents after correcting for multiple confounders. More research is needed in this field to understand the functioning of the juvenile vessels, and measurements and methodological approaches should be reconsidered.

A randomized controlled trial to assess the central hemodynamic response to exercise in patients with transient ischaemic attack and minor stroke

Early exercise engagement elicits meaningful changes in peripheral blood pressure in patients diagnosed with transient ischaemic attack (TIA) or minor stroke. However, central hemodynamic markers may provide clinicians with important diagnostic and prognostic information beyond that provided by peripheral blood pressure readings. The purpose of this single-centre, randomized, parallel-group clinical trial was to determine the effect of a 12-week aerobic exercise intervention on central and peripheral hemodynamic variables in patients with TIA or minor stroke. In this study, 47 participants (66±10 years) completed a baseline assessment, which involved the measurement of central and peripheral hemodynamic parameters, undertaken in the morning, in a fasted state. Participants were randomized to either a 12-week exercise or control group on completion of the baseline assessment. An identical follow-up assessment was completed post intervention. Central hemodynamic variables were assessed using an oscillometric device at both assessments. Analysis of covariance demonstrated a significant interaction for central and peripheral blood pressure and augmentation index (all P<0.05; η_p².09–.11), with the exercise group presenting lower values than the control group post intervention (118±17 vs 132±28 mm Hg for central blood pressure; 125±19 vs 138±28 mm Hg for peripheral blood pressure; 104±49 vs 115±67% for augmentation index). The present study demonstrates that participation in an exercise program soon after stroke/TIA diagnosis may elicit significant beneficial changes to a patient's central systolic blood pressure and augmentation index. This may positively impact upon the treatment strategies implemented by clinicians in the care of patients with TIA and minor stroke.

Association of affective temperaments with blood pressure and arterial stiffness in hypertensive patients: a cross-sectional study

Background

Affective temperaments (anxious, depressive, cyclothymic, irritable and hyperthymic) measure subclinical manifestations of major mood disorders. Furthermore, cumulating evidence suggests their involvement in somatic disorders as well. We aimed to assess associations between affective temperament scores and blood pressure and arterial stiffness parameters in hypertensive patients.

Methods

In this cross-sectional study, 173 patients with well-controlled or grade 1 chronic hypertension, with no history of depression, completed the TEMPS-A, Beck Depression Inventory (BDI) and Hamilton Anxiety Scale (HAM-A) questionnaires in three GP practices. Arterial stiffness was measured with tonometry (PulsePen).

Results

According to multiple linear regression analysis, cyclothymic temperament score was positively associated with brachial systolic blood pressure independently of age, sex, total cholesterol, brachial diastolic blood pressure, BDI, HAM-A and the use of alprazolam (β = 0.529, p = 0.042), while hyperthymic temperament score was negatively related to augmentation index independent of age, sex, smoking, heart rate, BDI, HAM-A and the use of alprazolam (β = -0.612, p = 0.013). A significant interaction was found between cyclothymic temperament score and sex in predicting brachial systolic blood pressure (p = 0.025), between irritable and anxious temperament scores and sex in predicting pulse wave velocity (p = 0.021, p = 0.023, respectively) and an interaction with borderline significance between hyperthymic temperament score and sex in predicting augmentation index (p = 0.052).

Conclusions

The present findings highlight elevated blood pressure among subjects with high cyclothymic temperament as well as an increased level of arterial stiffening in subjects with low hyperthymic scores suggesting that affective temperaments may play a role in the development of hypertension and arterial stiffening and may thus represent markers of cardiovascular risk. Sex differences were also present in these associations.

Effects of pacing modality on noninvasive assessment of heart rate dependency of indices of large artery function

Studies investigating the relationship between heart rate (HR) and arterial stiffness or wave reflections have commonly induced HR changes through in situ cardiac pacing. Although pacing produces consistent HR changes, hemodynamics can be different with different pacing modalities. Whether the differences affect the HR relationship with arterial stiffness or wave reflections is unknown. In the present study, 48 subjects [mean age, 78 ± 10 (SD), 9 women] with in situ cardiac pacemakers were paced at 60, 70, 80, 90, and 100 beats per min under atrial, atrioventricular, or ventricular pacing. At each paced HR, brachial cuff-based pulse wave analysis was used to determine central hemodynamic parameters, including ejection duration (ED) and augmentation index (AIx). Wave separation analysis was used to determine wave reflection magnitude (RM) and reflection index (RI). Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Pacing modality was found to have significant effects on the HR relationship with ED (P = 0.01), central aortic pulse pressure (P = 0.01), augmentation pressure (P < 0.0001), and magnitudes of both forward and reflected waves (P = 0.05 and P = 0.003, respectively), but not cfPWV (P = 0.57) or AIx (P = 0.38). However, at a fixed HR, significant differences in pulse pressure amplification (P < 0.001), AIx (P < 0.0001), RM (P = 0.03), and RI (P = 0.03) were observed with different pacing modalities. These results demonstrate that although the HR relationships with arterial stiffness and systolic loading as measured by cfPWV and AIx were unaffected by pacing modality, it should still be taken into account for studies in which mixed pacing modalities are present, in particular, for wave reflection studies.

Assessment of Arterial Stiffness in Korean Patients With Psoriasis by Cardio-Ankle Vascular Index

Many recent studies have suggested that psoriasis, a chronic, inflammatory, immune-mediated skin disease, is associated with increased risk of cardiovascular disease (CVD). We aimed to compare arterial stiffness in psoriasis and control patient groups using the cardio-ankle vascular index (CAVI) and to determine whether psoriasis is an independent risk factor for CVD. A total 103 patients with psoriasis and 103 age- and sex-matched controls were enrolled. Compared with controls, the patients showed a higher CAVI ( P = .03), particularly patients older than 40 years. The duration of psoriasis exhibited a positive correlative tendency with CAVI ( P = .066). Moreover, psoriasis is an independent predictor of arterial stiffness after adjusting for other factors ( P = .011). We suggest that psoriasis can be a risk factor for CVD, and older patients with psoriasis of longer disease duration should be monitored carefully for cardiovascular risk.

Sustained Improvement of Arterial Stiffness and Blood Pressure after Long-Term Rosuvastatin Treatment in Patients with Inflammatory Joint Diseases: Results from the RORA-AS Study

OBJECTIVE

Patients with inflammatory joint diseases (IJD) have a high prevalence of hypertension and increased arterial stiffness. The aim of the present study was to evaluate the effect of long-term rosuvastatin treatment on arterial stiffness, measured by augmentation index (AIx) and aortic pulse wave velocity (aPWV), and blood pressure (BP) in IJD patients with established atherosclerosis.

METHODS

Eighty-nine statin naïve IJD patients with carotid atherosclerotic plaque(s) (rheumatoid arthritis n = 55, ankylosing spondylitis n = 23, psoriatic arthritis n = 11) received rosuvastatin for 18 months to achieve low-density lipoprotein cholesterol goal ≤1.8 mmol/L. Change in AIx (ΔAIx), aPWV (ΔaPWV), systolic BP (ΔsBP) and diastolic BP (ΔdBP) from baseline to study end was assessed by paired samples t-tests. Linear regression was applied to evaluate associations between cardiovascular disease (CVD) risk factors, rheumatic disease specific variables and medication, and ΔAIx, ΔaPWV, ΔsBP and ΔdBP.

RESULTS

AIx, aPWV, sBP and dBP were significantly reduced from baseline to study end. The mean (95%CI) changes were: ΔAIx: -0.34 (-0.03, -0.65)% (p = 0.03), ΔaPWV: -1.69 (-0.21, -3.17) m/s2 (p = 0.03), ΔsBP: -5.27 (-1.61, -8.93) mmHg (p = 0.004) and ΔdBP -2.93 (-0.86, -5.00) mmHg (p = 0.01). In linear regression models, ∆aPWV was significantly correlated with ΔsBP and ΔdBP (for all: p<0.001).

CONCLUSIONS

There is an unmet need of studies evaluating CVD prevention in IJD patients. We have shown for the first time that long-term intensive lipid lowering with rosuvastatin improved arterial stiffness and induced a clinically significant BP reduction in patients with IJD. These improvements were linearly correlated and may represent novel insight into the pleiotropic effects by statins.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01389388.

Serum osteoprotegerin levels associated with the aortic augmentation index in renal transplant recipients

OBJECTIVES

Arterial stiffness is recognized as an independent risk factor for cardiovascular morbidity and mortality. Recent studies found that osteoprotegerin (OPG) is associated with arterial stiffness and may reflect endothelial dysfunction. The aim of this study was to evaluate the relationship between fasting serum OPG levels and the aortic augmentation index (AIx) in renal transplant recipients.

MATERIALS AND METHODS

Fasting blood samples were obtained from 66 renal transplant recipients. The aortic AIx was measured using a validated tonometry system (SphygmoCor). Serum OPG levels were measured using a commercial enzyme-linked immunosorbent assay kit.

RESULTS

Univariate linear analysis of the aortic AIx in renal transplant recipients revealed that body fat mass (r = 0.377, p = 0.002), aortic diastolic blood pressure (DBP; r = 0.307, p = 0.020), triglycerides (r = 0.260, p = 0.035), and logarithmically transformed OPG (log-OPG, r = 0.402, p < 0.001) were positively correlated, whereas height (r = 0.361, p = 0.004) and body weight (r = 0.212, p = 0.041) were negatively correlated with the aortic AIx in renal transplant recipients. Multivariate forward stepwise linear regression analysis of the factors significantly associated with the aortic AIx showed that log-OPG (R2 = 0.213, p < 0.001), height (R2 = 0.081, p = 0.009), and aortic DBP (R2 = 0.058, p = 0.022) were independent predictors of the aortic AIx in renal transplant recipients.

CONCLUSION

These results suggest that the serum fasting OPG level is associated with the aortic AIx in renal transplant recipients.