A method to assess linear self-predictability of physiologic processes in the frequency domain: application to beat-to-beat variability of arterial compliance

The concept of self-predictability plays a key role for the analysis of the self-driven dynamics of physiological processes displaying richness of oscillatory rhythms. While time domain measures of self-predictability, as well as time-varying and local extensions, have already been proposed and largely applied in different contexts, they still lack a clear spectral description, which would be significantly useful for the interpretation of the frequency-specific content of the investigated processes. Herein, we propose a novel approach to characterize the linear self-predictability (LSP) of Gaussian processes in the frequency domain. The LSP spectral functions are related to the peaks of the power spectral density (PSD) of the investigated process, which is represented as the sum of different oscillatory components with specific frequency through the method of spectral decomposition. Remarkably, each of the LSP profiles is linked to a specific oscillation of the process, and it returns frequency-specific measures when integrated along spectral bands of physiological interest, as well as a time domain self-predictability measure with a clear meaning in the field of information theory, corresponding to the well-known information storage, when integrated along the whole frequency axis. The proposed measure is first illustrated in a theoretical simulation, showing that it clearly reflects the degree and frequency-specific location of predictability patterns of the analyzed process in both time and frequency domains. Then, it is applied to beat-to-beat time series of arterial compliance obtained in young healthy subjects. The results evidence that the spectral decomposition strategy applied to both the PSD and the spectral LSP of compliance identifies physiological responses to postural stress of low and high frequency oscillations of the process which cannot be traced in the time domain only, highlighting the importance of computing frequency-specific measures of self-predictability in any oscillatory physiologic process.

Smartphone-Based Blood Pressure Monitoring via the Oscillometric Finger Pressing Method: Analysis of Oscillation Width Variations Can Improve Diastolic Pressure Computation

OBJECTIVE

Oscillometric finger pressing is a potential method for absolute blood pressure (BP) monitoring via a smartphone. The user presses their fingertip against a photoplethysmography-force sensor unit on a smartphone to steadily increase the external pressure on the underlying artery. Meanwhile, the phone guides the finger pressing and computes systolic BP (SP) and diastolic BP (DP) from the measured blood volume oscillations and finger pressure. The objective was to develop and evaluate reliable finger oscillometric BP computation algorithms.

METHODS

The collapsibility of thin finger arteries was exploited in an oscillometric model to develop simple algorithms for computing BP from the finger pressing measurements. These algorithms extract features from "width" oscillograms (oscillation width versus finger pressure functions) and the conventional "height" oscillogram for markers of DP and SP. Finger pressing measurements were obtained using a custom system along with reference arm cuff BP measurements from 22 subjects. Measurements were also obtained during BP interventions in some subjects for 34 total measurements.

RESULTS

An algorithm employing the average of width and height oscillogram features predicted DP with correlation of 0.86 and precision error of 8.6 mmHg with respect to the reference measurements. Analysis of arm oscillometric cuff pressure waveforms from an existing patient database provided evidence that the width oscillogram features are better suited to finger oscillometry.

CONCLUSION

Analysis of oscillation width variations during finger pressing can improve DP computation.

SIGNIFICANCE

The study findings may help in converting widely available devices into truly cuffless BP monitors for improving hypertension awareness and control.

Computation of Vascular Parameters: Implementing Methodology and Performance Analysis

This paper presents the feasibility of automated and accurate in vivo measurements of vascular parameters using an ultrasound sensor. The continuous and non-invasive monitoring of certain parameters, such as pulse wave velocity (PWV), blood pressure (BP), arterial compliance (AC), and stiffness index (SI), is crucial for assessing cardiovascular disorders during surgeries and follow-up procedures. Traditional methods, including cuff-based or invasive catheter techniques, serve as the gold standard for measuring BP, which is then manually used to calculate AC and SI through imaging algorithms. In this context, the Continuous and Non-Invasive Vascular Stiffness and Arterial Compliance Screener (CaNVAS) is developed to provide continuous and non-invasive measurements of these parameters using an ultrasound sensor. By driving 5 MHz (ranging from 2.2 to 10 MHz) acoustic waves through the arterial walls, capturing the reflected echoes, and employing pre-processing techniques, the frequency shift is utilized to calculate PWV. It is observed that PWV measured by CaNVAS correlates exponentially with BP values obtained from the sphygmomanometer (BPMR-120), enabling the computation of instantaneous BP values. The proposed device is validated through measurements conducted on 250 subjects under pre- and post-exercise conditions, demonstrating an accuracy of 95% and an average coefficient of variation of 12.5%. This validates the reliability and precision of CaNVAS in assessing vascular parameters.

The association between arterial compliance, as assessed by PTC1 and PTC2 from radial artery waveforms, and age, sex, and race/ethnicity

BACKGROUND

There is limited literature on differences in arterial compliance, as assessed from arterial pressure waveforms, with age, sex, and race/ethnicity. PTC1 and PTC2 are indices of arterial compliance, which are derived from a Windkessel model of the waveform, relatively easy to obtain, and associated with cardiovascular disease.

METHOD

PTC1 and PTC2 were computed from radial artery waveforms from participants of the Multi-Ethnic Study of Atherosclerosis at baseline and again 10 years later. We evaluated the association of PTC1, PTC2, and 10-year change in PTC1 and PTC2 with age, sex, and race/ethnicity.

RESULTS

Among 6245 participants in 2000-2002 (mean ± SD of age was 62 ± 10 years; 52% female; 38% White, 12% Chinese, 27% Black, and 23% Hispanic/Latino), means ± SDs for PTC1 and PTC2 were 394 ± 334 and 94 ± 46 ms. After adjustment for cardiovascular disease risk factors, mean PTC2 was 1.1 ms (95% confidence interval: 1.0, 1.2) lower (arterial stiffness was greater) per year older age, was 22 ms (19, 24) lower for females, and varied by race/ethnicity ( P  < 0.001; e.g., 5 ms lower for Blacks compared with Whites), although the differences were smaller at older ages ( P  < 0.001 for age-sex, P  < 0.001 for age-race/ethnicity interactions). Among 3701 participants with repeat measurements in 2010-2012, arteries had stiffened (mean ± SD 10-year decrease in PTC2: 13 ± 46 ms) consistent with cross-sectional age-trend and tended to stiffen less for females and Blacks consistent with cross-sectional age-interactions.

CONCLUSION

Differences in arterial compliance by age, sex, and race/ethnicity lend support to identify and act on societal factors that may drive health disparities.

Effects of acute cervical stretching on arterial wall elastic properties

Purpose: Acute (immediate) or regular (mid- or long-term) stretching increases arterial compliance and reduces arterial stiffness. Stretching is widely known to induce arterial functional factor changes, but it is unclear whether stretching alters arterial structural factors. Ultrasound shear wave elastography can quantify the distribution of tissue elastic properties as an index of arterial structural factors. This study thus aimed to examine the effects of acute cervical stretching on arterial wall tissue elastic properties. Methods: Seventeen healthy young adults participated in two different trials for 15 min in random order on separate days: a resting and sitting trial (CON) and a supervised cervical stretching trial (CS). In CS, subjects performed 10 different stretches. At each site, the stretch was held for 30 s followed by a 10-s relaxation period. In CON, subjects rested on a chair for 15 min. Results: After the experiment, carotid arterial compliance, assessed by combined ultrasound imaging and applanation tonometry, was significantly increased in CS, but not in CON. However, there was no significant change in tissue elasticity properties of the arterial wall in either trial, as assessed by ultrasound shear wave elastography. Conclusion: Acute cervical stretching significantly increased carotid artery compliance in young participants, but did not reduce elastic tissue properties (i.e., arterial structural factors) of the carotid artery wall. These results strongly suggest that changes in structural factors have little relation to stretching-induced acute increases in arterial compliance.

Cardiac contractility is a key factor in determining pulse pressure and its peripheral amplification

Background

Arterial stiffening and peripheral wave reflections have been considered the major determinants of raised pulse pressure (PP) and isolated systolic hypertension, but the importance of cardiac contractility and ventricular ejection dynamics is also recognised.

Methods

We examined the contributions of arterial compliance and ventricular contractility to variations in aortic flow and increased central (cPP) and peripheral (pPP) pulse pressure, and PP amplification (PPa) in normotensive subjects during pharmacological modulation of physiology, in hypertensive subjects, and in silico using a cardiovascular model accounting for ventricular-aortic coupling. Reflections at the aortic root and from downstream vessels were quantified using emission and reflection coefficients, respectively.

Results

cPP was strongly associated with contractility and compliance, whereas pPP and PPa were strongly associated with contractility. Increased contractility by inotropic stimulation increased peak aortic flow (323.9 ± 52.8 vs. 389.1 ± 65.1 ml/s), and the rate of increase (3193.6 ± 793.0 vs. 4848.3 ± 450.4 ml/s2) in aortic flow, leading to larger cPP (36.1 ± 8.8 vs. 59.0 ± 10.8 mmHg), pPP (56.9 ± 13.1 vs. 93.0 ± 17.0 mmHg) and PPa (20.8 ± 4.8 vs. 34.0 ± 7.3 mmHg). Increased compliance by vasodilation decreased cPP (62.2 ± 20.2 vs. 45.2 ± 17.8 mmHg) without altering d P / d t , pPP or PPa. The emission coefficient changed with increasing cPP, but the reflection coefficient did not. These results agreed with in silico data obtained by independently changing contractility/compliance over the range observed in vivo.

Conclusions

Ventricular contractility plays a key role in raising and amplifying PP, by altering aortic flow wave morphology.

Mathematical Modeling of Oscillometric Blood Pressure Measurement: A Complete, Reduced Oscillogram Model

OBJECTIVE

Oscillogram modeling is a powerful tool for understanding and advancing popular oscillometric blood pressure (BP) measurement. A reduced oscillogram model relating cuff pressure oscillation amplitude ( ∆O) to external cuff pressure of the artery ( Pe) is: [Formula: see text], where g(P) is the arterial compliance versus transmural pressure ( P) curve, Ps and Pd are systolic and diastolic BP, and k is the reciprocal of the cuff compliance. The objective was to determine an optimal functional form for the arterial compliance curve.

METHODS

Eight prospective, three-parameter functions of the brachial artery compliance curve were compared. The study data included oscillometric arm cuff pressure waveforms and invasive brachial BP from 122 patients covering a 20-120 mmHg pulse pressure range. The oscillogram measurements were constructed from the cuff pressure waveforms. Reduced oscillogram models, inputted with measured systolic and diastolic BP and each parametric brachial artery compliance curve function, were optimally fitted to the oscillogram measurements in the least squares sense.

RESULTS

An exponential-linear function yielded as good or better model fits compared to the other functions, with errors of 7.9±0.3 and 5.1±0.2% for tail-trimmed and lower half-trimmed oscillogram measurements. Importantly, this function was also the most tractable mathematically.

CONCLUSION

A three-parameter exponential-linear function is an optimal form for the arterial compliance curve in the reduced oscillogram model and may thus serve as the standard function for this model henceforth.

SIGNIFICANCE

The complete, reduced oscillogram model determined herein can potentially improve oscillometric BP measurement accuracy while advancing foundational knowledge.

The renin-angiotensin-aldosterone system, neurohumoral axis and cardiovascular mortality in LURIC

Although neurohormones and Renin-Angiotensin-Aldosterone-System (RAAS) components are important predictors of cardiovascular mortality (CVM), their importance for predicting outcomes in patients with/without RAAS-blockers and different degrees of arterial stiffness is less understood. We therefore analyzed long-term data from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study in 3316 patients subdivided according to pulse pressure (PP) and RAAS-blocker use. Patients on RAAS-inhibition had higher renin and noradrenaline, lower aldosterone and aldosterone/renin quotient (ARQ). Renin and noradrenaline significantly predicted CVM in patients without RAAS-blocker (HR = 1.17, 1.15) and in patients receiving angiotensin-converting-enzyme (ACE) inhibitors (HR = 1.17, 1.29), whereas aldosterone predicted CVM only in patients receiving ACE-inhibitors (HR = 1.13). CVM was predicted independently from PP by renin, noradrenaline and angiotensin II. Independently from RAAS inhibition renin decreased and ARQs increased with rising PP. Furthermore, noradrenaline increased with PP, but only without ACE-inhibition. The HR for CVM in the ACE-inhibitor group were 1.29, 1.28, 1.29 for renin in the first, second and third PP quartiles and 1.22, and 1.19 for aldosterone in the second and fourth quartile. Furthermore, we showed that noradrenaline predicts CVM in all PP quartiles in patients with ACE-inhibition. In the RAAS-blocker-free group, the HR for renin for CVM were 1.36 and 1.18 in the third and fourth PP quartiles, but neither aldosterone nor noradrenaline were predictive for CVM within the PP quartiles. Renin and noradrenaline are strong predictors of CVM regardless of RAAS blockade, whereas aldosterone is predictive only in the ACE-inhibitor group. Catecholamines but not renin are associated with rising PP.

Changes in Arterial Stiffness in Response to Various Types of Exercise Modalities: A Narrative Review on Physiological and Endothelial Senescence Perspectives

Arterial stiffness is a reliable independent predictor of cardiovascular events. Exercise training might enhance arterial compliance through improved metabolic health status. Different modes of exercise may have different effects on arterial stiffness. However, the interactions among different modes of exercise on endothelial senescence, the development of arterial vascular stiffness, and the associated molecular mechanisms are not completely understood. In this narrative review, we evaluate the current evidence focusing on the effects of various exercise modes on arterial stiffness and vascular health, and the known underlying physiological mechanisms are discussed as well. Here, we discuss the most recent evidence of aerobic exercise, high-intensity interval training (HIIT), and resistance exercise (RE) on arterial stiffness and endothelial senescence in physiological and cellular studies. Indeed, aerobic, HIIT, and progression RE-induced arterial compliance may reduce arterial stiffness by effectively promoting nitric oxide (NO) bioavailability and reducing endothelial senescence. However, the transient increase in inflammation and sympathetic activation may contribute to the temporary elevation in arterial stiffness following whole-body high-intensity acute resistance exercise.

Immediate post-exercise blood pressure and arterial stiffness in hypertensive and normotensive older females

Although it has been suggested that increased arterial stiffness is linked to exaggerated blood pressure (BP) from brief moderate exercise, it is not clear whether this occurs in older adults with and without hypertension. This study investigates whether the immediate post‐exercise systolic BP following brief moderate exercise is associated with arterial stiffness in older females with different BP status. This cross‐sectional study included 191 older females aged 60–80 years without known cardiovascular disease (CVD). Arterial stiffness was determined by aortic pulse wave velocity (aPWV). Systolic BP was measured before and immediately following a 3‐min moderate walking test (stage 1 Bruce protocol). Specific quartile‐based thresholds were used to define an exaggerated immediate post‐exercise systolic BP for hypertensive and normotensive older females (quartile 4 as an exaggerated response). Traditional CVD risk factors were assessed (covariates). Older females from the highest quartile of immediate post‐exercise absolute systolic BP showed higher aPWV compared to their peers from the lowest quartile (β = .22 m/s, p = .018). The quartile‐based threshold to define the exaggerated post‐exercise systolic BP was higher in hypertensive than in normotensive older females (174 vs. 172 mmHg). In summary, exaggerated immediate post‐exercise systolic BP following a brief moderate exercise is associated with higher arterial stiffness in older females with different BP status.

Potential role of the corpus luteum in maternal cardiovascular adaptation to pregnancy and preeclampsia risk

Studies in the gravid rat model revealed a key role for the corpus luteal hormone, relaxin, in the maternal circulatory changes of early pregnancy epitomized by profound systemic vasodilation and increased arterial compliance. To determine whether the corpus luteum may play a similar role in human pregnancy, women who conceived by in vitro fertilization were studied. Implementation of artificial (programmed) cycles for embryo transfers, which precluded the formation of a corpus luteum, was associated with notable attenuation of the gestational rise in cardiac output and fall in carotid-femoral pulse wave velocity (reflecting impairment of arterial dilation and increased compliance, respectively) and deficiencies in other cardiovascular changes normally observed during the first trimester. Cardiac output and carotid-femoral pulse wave velocity were restored after the first trimester of pregnancy, consistent with rescue by placental vasodilators, such as placental growth factor. In addition, a potential role of corpus luteal factors in reducing the risk of developing preeclampsia was hypothesized. In most single and multiple center, prospective and retrospective cohort (and registry) studies, the risk of developing preeclampsia and preeclampsia with severe features was increased specifically in women undergoing autologous frozen embryo transfer in artificial cycles without the formation of a corpus luteum relative to natural, modified natural, stimulated, or controlled ovarian stimulation cycles and spontaneous pregnancies-all associated with the formation of at least 1 corpus luteum. Taken together, these observational studies are sufficiently compelling to warrant randomized clinical trials comparing preeclampsia risk in autologous frozen embryo transfer in natural vs artificial cycles. Impaired endometrial function because of suboptimal hormonal administration is an alternative but not mutually exclusive explanation for increased preeclampsia risk in autologous frozen embryo transfer in artificial cycles. Potential mechanisms by which the corpus luteum may reduce the risk of developing preeclampsia and whether autologous frozen embryo transfer in artificial cycles is associated with increased risk of preterm preeclampsia, term preeclampsia, or both are discussed. Last, suggestions for future investigations are noted.

The effect of acute aerobic exercise on arterial stiffness in individuals with different body fat percentages: A cross-sectional study

BACKGROUND

Body fat percentage were positively correlated with arterial stiffness, but the acute change in arterial stiffness after aerobic exercise in individuals with different body fat percentages remains unclear. This study was aimed to determine the effect of acute aerobic exercise on arterial stiffness in individuals with different body fat percentages.

METHODS

Individuals who both participated in the seventh survey of the Kailuan study and the fifth iteration of National Physical Fitness Monitoring were enrolled in our study. All participants underwent measurement of brachial-ankle pulse wave velocity, blood pressure, and heart rate before and after a two-stage load test on cycle ergometry. Additionally, the generalized linear model was established to analyse between-group differences of the change in brachial-ankle pulse wave velocity before and after exercise for individuals with different body fat percentages.

RESULTS

The participants (N = 940, 36.8 ± 7.7years old, all male) were divided into: Q1 10.0-19.3%, Q2 19.3-23.3%, Q3 23.3-27.1% and Q4 27.1-37.7% by body fat percentage quartile. Overall, after exercise, brachial-ankle pulse wave velocity decreased significantly (before, 1,375.1 ± 209.1; after, 1,341.5 ± 208.0cm/s; p < 0.01). After adjusting for confounding factors, the generalized linear model showed that the β values and 95% confidence interval (CI) of Q1, Q2 and Q3 groups were -38.1 (95% CI: -57.3, -19.0), -8.5 (95% CI: -25.8, 3.7),-3.7 (95% CI: -20.5, 13.0), respectively, when compared with Q4. For an increase in body fat percentage by one standard deviation (5.8%), β = 14.5 (95% CI: 7.3, 21.6). Similar results were obtained in sensitivity analyses.

CONCLUSIONS

Acute aerobic exercise had a positive effect on the arterial stiffness of adults with different body fat percentages. Compared with individuals with high body fat percentages, the arterial stiffness of people with low body fat percentages had significant reduction after exercise.

Standalone sauna vs exercise followed by sauna on cardiovascular function in non-naïve sauna users: A comparison of acute effects

BACKGROUND AND AIMS

Sauna bathing and aerobic exercise have each been shown to affect cardiovascular function. However, direct comparisons between standalone sauna bathing and a combination of exercise and sauna on vascular indices remain limited. Therefore, we conducted a cross-over study using matched durations to explore the hemodynamic changes of sauna exposure when compared to a combination of aerobic exercise and sauna exposure.

METHODS

Participants (N = 72) with at least one cardiovascular risk factor underwent, on two separate occasions: (a) a 30-minute sauna at 75°C (SAUNA) and (b) the combination of a 15-minute cycling exercise at 75% maximum heart rate followed by 15-minute sauna exposure (EX+SAUNA). Relative changes to arterial stiffness (PWV), augmentation index (Alx), brachial systolic and diastolic blood pressure (SBP and DBP), central SBP (cSBP), mean arterial pressure (MAP), and heart rate (HR) were compared PRE-POST and pre- to 30-minutes post-intervention (PRE-POST30).

RESULTS

Baseline SBP and DBP were 143 (SD 18) mmHg and 86 (SD 10) mmHg, respectively. From PRE-POST, SAUNA had lower DBP (mean difference [95% CI] 2.5 [1.0, 4.1], P = .002) and MAP (2.5 [0.6, 4.3], P = .01). However, EX+SAUNA had lower SBP (-2.7 [-4.8, -0.5], P = .02), DBP (-1.8 [-3.3, -0.4], P = .01), and MAP (-2.0 [-3.5, -0.5], P = .009) PRE-POST30. There were no statistically significant differences between SAUNA and EX+SAUNA for other measured parameters.

CONCLUSION

This study demonstrated that when matched for duration, EX+SAUNA and SAUNA elicit comparable acute hemodynamic alterations in middle-aged participants with cardiovascular risk factors. The sauna is a suitable option for acute blood pressure reductions in those who are unable to perform aerobic exercise, and may be a viable lifestyle treatment option to improve blood pressure control.

Treatment Site Does Not Affect Changes in Pulse Wave Velocity but Treatment Length and Device Selection Are Associated With Increased Pulse Wave Velocity After Thoracic Endovascular Aortic Repair

Background: Endovascular treatment of aortic aneurysm is associated with an increase in pulse wave velocity (PWV) after surgery. However, the effect of different types of endovascular devices on PWV at different sites of the thoracic aorta remains unclear.

Objectives: The purposes of this study were (1) to investigate the changes in PWV after endovascular treatment of thoracic aortic aneurysm; (2) to evaluate whether there is a difference in the changes in PWV at different treatment sites; and (3) to evaluate the effect of treatment length on changes in PWV.

Methods: From July 2008 to July 2021, 276 patients underwent endovascular treatment of the true thoracic aortic aneurysm. Of these patients, 183 patients who underwent preoperative and postoperative PWV measurement within 1 year of surgery were included in the study. The treatment length index was calculated by treatment length divided by the height of the patients.

Results: Five different types of endovascular devices were used (Najuta, Kawasumi Laboratories, Inc., Tokyo, Japan; TAG, W.L. Gore & Associates, Inc., AZ, USA; Relay, Bolton Medical, Inc., FL, USA; Talent/Valiant, Medtronic, MN, USA; and Zenith, Cook Medical, IN, USA). There was no significant change in PWV in patients receiving Najuta (Before: 2,040 ± 346.8 cm/s vs. After: 2,084 ± 390.5 cm/s, p = 0.14). However, a significant increase was observed in other devices: TAG (Before: 2,090 ± 485.9 cm/s vs. After: 2,300 ± 512.1 cm/s, p = 0.025), Relay (Before: 2,102 ± 465.3 cm/s vs. After: 2,206 ± 444.4 cm/s, p = 0.004), Valiant (Before: 1,696 ± 330.2 cm/s vs. After: 2,186 ± 378.7 cm/s, p < 0.001), and Zenith (Before: 2,084 ± 431.7 cm/s vs. After: 2,321 ± 500.6 cm/s, p < 0.001). There was a significant increase in PWV in patients treated from aortic arch (Before: 2,006 ± 333.7 cm/s vs. After: 2,132 ± 423.7 cm/s, p < 0.001) and patients treated from descending thoracic aorta (Before: 2,116 ± 460.9 cm/s vs. After: 2,292 ± 460.9 cm/s, p < 0.001). Multivariate analysis showed that treatment site was not an independent factor associated with changes in PWV. However, Najuta (Coef −219.43, 95% CI −322.684 to −116.176, p < 0.001) and treatment index (Coef 147.57, 95% CI 24.826 to 270.312, p = 0.019) were independent factors associated with changes in PWV.

Conclusion: Najuta did not show a significant increase in PWV, while other commercially available devices showed a significant increase. The treatment site did not have a different effect on PWV. However, the treatment length was an independent factor associated with an increase in PWV.

Domains of Physical Activity in Relation to Stiffness Index in the General Population

Background

Regular exercise training represents an important modifier of arterial stiffness (AS). Therefore, sex‐specific relations between domains of physical activity (PA; commuting, domestic, and leisure‐time PA, including active sport and occupational PA) with AS were investigated.

Methods and Results

Stiffness index by digital photoplethysmography was investigated in 12 650 subjects from the GHS (Gutenberg Health Study). Self‐reported PA was evaluated by the “Short Questionnaire to Assess Health‐Enhancing Physical Activity” and reported as activity score peer week, being a combined measure of duration, frequency, and intensity of PA. Multivariable linear regression analysis demonstrated strong beneficial effects of repetitive activities, such as active commuting or leisure‐time PA–related walking on AS in men, but not in women. Lower AS associated with endurance training was also found among men and premenopausal women. In contrast, intense occupational PA was related to stiffer vessels in men (P<0.0001) and women (P=0.0021) in a fully adjusted model. Combination of both, performing endurance training and having stiffness index values below median, resulted in the best survival. In contrast, subjects with elevated stiffness index at baseline without any endurance activities demonstrated the worst survival.

Conclusions

In this population representative sample, a differential impact of domains of self‐reported PA on AS was demonstrated. Our data strengthen the importance of regular endurance PA to induce a reduction of AS, which, in turn, may improve cardiovascular prognosis. We also report deleterious effects of intense occupational PA on stiffness index, a finding that needs further confirmation by larger prospective trials.

Insulin stimulation reduces aortic wave reflection in adults with metabolic syndrome

Adults with metabolic syndrome (MetS) have increased fasting arterial stiffness and altered central hemodynamics that contribute, partly, to increased cardiovascular disease (CVD) risk. Although insulin affects aortic wave reflections in healthy adults, the effects in individuals with MetS are unclear. We hypothesized that insulin stimulation would reduce measures of pressure waveforms and hemodynamics in people with MetS. Thirty-five adults with obesity (27 women; 54.2 ± 6.0 yr; 37.1 ± 4.8 kg/m²) were selected for MetS (ATP III criteria) following an overnight fast. Pulse wave analysis was assessed using applanation tonometry before and after a 2-h euglycemic-hyperinsulinemic clamp (90 mg/dL, 40 mU/m²/min). Deconvolution analysis was used to decompose the aortic waveform [augmentation index corrected to heart rate of 75 beats/min (AIx@75); augmentation pressure (AP)] into backward and forward pressure components. Aerobic fitness (V̇o_2max), body composition (DXA), and blood biochemistries were also assessed. Insulin significantly reduced augmentation index (AIx@75, 28.0 ± 9.6 vs. 23.0 ± 9.9%, P < 0.01), augmentation pressure (14.8 ± 6.4 vs. 12.0 ± 5.7 mmHg, P < 0.01), pulse pressure amplification (1.26 ± 0.01 vs. 0.03 ± 0.01, P = 0.01), and inflammation [high-sensitivity C-reactive protein (hsCRP): P = 0.02; matrix metallopeptidase 7 (MMP-7): P = 0.03] compared to fasting. In subgroup analyses to understand HTN influence, there were no insulin stimulation differences on any outcome. V̇o_2max, visceral fat, and blood potassium correlated with fasting AIx@75 (r = -0.39, P = 0.02; r = 0.41, P = 0.03; r = -0.53, P = 0.002). Potassium levels were also associated with insulin-mediated reductions in AP (r = 0.52, P = 0.002). Our results suggest insulin stimulation improves indices of aortic reflection in adults with MetS.NEW & NOTEWORTHY This study is one of the first to investigate the effects of insulin on central and peripheral hemodynamics in adults with metabolic syndrome. We provide evidence that insulin infusion reduces aortic wave reflection, potentially through a reduction in inflammation and/or via a potassium-mediated vascular response.

The association between indices of blood pressure waveforms (PTC1 and PTC2) and incident heart failure

OBJECTIVES

The radial artery pulse waveform is a continuous measure of pressure throughout the cardiac cycle, and thus can provide more information than just systolic and diastolic blood pressures. New indices based on a Windkessel model of the waveform, PTC1 and PTC2, are related to arterial compliance and add information for prediction of incident cardiovascular disease (coronary heart disease, stroke, myocardial infarction) but their association with heart failure is unknown.

METHODS

Among 6229 adults (mean age 62 years) from four race/ethnic groups who were initially free of clinical cardiovascular disease and heart failure in 2000-2002, we evaluated the associations of baseline PTC1 and PTC2 with incident heart failure.

RESULTS

Mean ± standard deviation PTC1 and PTC2 were 394 ± 334 and 94 ± 46 ms, respectively. During a median of 15.7 years follow-up, there were 357 heart failure events (148 with reduced, 150 with preserved, and 59 with unknown ejection fraction). After adjustment for traditional risk factors, the hazard ratio for heart failure per 1 standard deviation higher PTC2 was 0.73 (95% confidence interval: 0.63--0.85). Higher PTC2 was also significantly associated with lower risk of heart failure with reduced ejection fraction (hazard ratio = 0.67; 95% confidence interval: 0.56--0.80). There was no evidence of a significant association between PTC2 and heart failure with preserved ejection fraction or between PTC1 and heart failure.

CONCLUSION

The PTC2 measure of the radial artery pulse waveform may represent a novel phenotype related to heart failure, especially heart failure with reduced ejection fraction.

Stature is negatively associated with increased arterial stiffness after high-intensity bicep curls training in young Japanese men

Reports have indicated that high-intensity resistance training (RT) increases or does not change arterial stiffness. Meanwhile, higher stature has been suggested to have a protective effect on cardiovascular disease and arterial stiffness. Stature could explain the disagreement in the reported effects of RT on arterial stiffness. This study was aimed at investigating whether stature is related to RT-induced change in arterial stiffness. Thirty-six young Japanese men were assigned to the control (n = 15) and training groups (n = 21). RT programme consisted of supervised bicep curls 3 days per week for 4 weeks (5 sets of 10 repetitions at 75% of 1-repetition maximum). Arterial compliance (AC) and β-stiffness index (via combination of ultrasound and carotid pressure waveforms) were measured in all participants. To verify the effect of stature on RT-induced change in arterial stiffness, the training group was divided into tertiles of stature: lower, middle, and higher stature groups (each group, n = 7). RT significantly decreased AC and increased β-stiffness index in only the lower stature group (both, P < 0.05). Moreover, stature was positively associated with decreased AC and negatively associated with increased β-stiffness index, even after adjusting for confounders including changes in relative strength, pulse pressure, and arterial distension (P < 0.05). The present results suggest that short stature contributes to the increase in arterial stiffness induced by RT in young Japanese men. The present findings suggest that stature should be taken into consideration when designing/engaging in RT programme, due to potential implications for cardiovascular health.Highlights Participants were divided into 3 groups according to tertiles of statures, and arterial stiffness of lower stature group (range of stature: 161.0-169.8 cm) increased after resistance training in young Japanese men, but not middle and higher stature group.Stature was negatively associated with the changed arterial stiffness by resistance training.This study suggests that short stature contributes to the elevation in arterial stiffness elicited by resistance training.

Influences of Recreational Tennis-Playing Exercise Time on Cardiometabolic Health Parameters in Healthy Elderly: The ExAMIN AGE Study

BACKGROUND

Aging and chronic degeneration are the primary threats to cardiometabolic health in elderly populations. Regular appropriate exercise would benefit the advanced aging population.

PURPOSE

This study investigates whether the degree of weekly tennis participation exhibits differences in primary cardiometabolic parameters, including arterial stiffness, inflammation, and metabolic biomarkers in elderly tennis players.

METHODS

One hundred thirty-five long-term participants in elder tennis (>50 years old) were initially screened. Twenty-six eligible and voluntary subjects were divided into high tennis time group (HT) (14 ± 1.3 h/week) and low tennis time group (LT) (4.5 ± 0.7 h/week) by stratification analysis based on the amount of tennis playing activity time. The brachial-ankle pulse wave velocity (baPWV), blood pressure, ankle-brachial index (ABI), blood metabolic biomarkers, and insulin resistance were measured to compare the difference between HT and LT groups.

RESULTS

The baPWV was significantly lower in the HT group than that in the LT group (1283.92 ± 37.01 vs. 1403.69 ± 53.71 cm/s, p < 0.05). We also found that the HT insulin-resistant homeostasis model assessment (HOMA-IR) was significantly lower than that of LT (1.41 ± 0.11 vs. 2.27 ± 0.48 μIU/mL, p < 0.05). However, the blood lipid biomarkers (glucose, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride) were not statistical different between HT and LT groups (p > 0.05).

CONCLUSION

We demonstrated that under the condition of similar daily physical activity level, elderly with a higher time of tennis-playing (HT group) exhibited relatively lower arterial stiffness (lower PWV) and lower insulin resistance compared to those with lower time tennis-playing (LT).

Sedentary Behavior in Childhood, Lower Arterial Compliance and Decreased Endothelial Function-Cross Sectional Data From a German School Cohort

BACKGROUND

Endothelial function by flow-mediated dilatation assesses early markers of atherosclerotic progression. Greater amounts of physical activity and physical fitness in children are associated with cardiovascular health benefits. We aimed to explore factors, influencing endothelial function and arterial compliance in a cohort of healthy school children.

METHODS

The 94 participants (41 girls, 53 boys) in the study were young, healthy children from a German school cohort. Anthropometric data, body composition and blood pressure were assessed. Blood was drawn (8 h overnight fast), assessing total cholesterol, high density lipoprotein and low density lipoprotein and triglycerides. Endothelial function was diagnosed by flow-mediated dilatation with ultrasonography (ALOKA/Hitachi, Prosound alpha 6). Tracking gates were set on the intima in B-mode. The waveform of diameter changes over the cardiac cycle was displayed in real time using the FMD-mode of the eTRACKING system. Changes in arterial diameter at baseline, ischaemia and vasodilatation were measured. A symptom limited pulmonary exercise test on a bicycle ergometer was performed to test cardiorespiratory fitness. Physical activity was assessed using GT3x accelerometers (Actigraph, USA), over 4 days (including 1 week-end day), with a minimum wear-time duration of 10 h.

RESULTS

The median age was 12.2 years (11.8-12.8). Children were normal weight, blood lipid profiles (cholesterol, high-density lipoprotein, low-density lipoprotein, triglyceride) were in normal range. Baseline measurements during the diagnostics of endothelial function revealed higher arterial compliance of the brachial artery in boys. Boys' cardiorespiratory fitness was higher than compared to girls. Boys met the recommendations of 60 min moderate to vigorous activity, whereas girls were significantly less active and did not meet current recommendations. More time spent in sedentary activity was the main predictor for lower arterial compliance (adjusted for age and sex), accounting for 14% of the variance. No significant model revealed, analyzing the influencing factors such as anthropometric data, blood lipids, physical activity and fitness on endothelial function.

CONCLUSION

This is the first study on endothelial function in association to objectively measured physical activity and cardiorespiratory fitness in healthy school children in Germany. The study highlights the importance of reducing time spent being sedentary to maintain endothelial health.

A Randomized Trial on the Effect of Phosphate Reduction on Vascular End Points in CKD (IMPROVE-CKD)

BACKGROUND

Hyperphosphatemia is associated with increased fibroblast growth factor 23 (FGF23), arterial calcification, and cardiovascular mortality. Effects of phosphate-lowering medication on vascular calcification and arterial stiffness in CKD remain uncertain.

METHODS

To assess the effects of non-calcium-based phosphate binders on intermediate cardiovascular markers, we conducted a multicenter, double-blind trial, randomizing 278 participants with stage 3b or 4 CKD and serum phosphate >1.00 mmol/L (3.10 mg/dl) to 500 mg lanthanum carbonate or matched placebo thrice daily for 96 weeks. We analyzed the primary outcome, carotid-femoral pulse wave velocity, using a linear mixed effects model for repeated measures. Secondary outcomes included abdominal aortic calcification and serum and urine markers of mineral metabolism.

RESULTS

A total of 138 participants received lanthanum and 140 received placebo (mean age 63.1 years; 69% male, 64% White). Mean eGFR was 26.6 ml/min per 1.73 m2; 45% of participants had diabetes and 32% had cardiovascular disease. Mean serum phosphate was 1.25 mmol/L (3.87 mg/dl), mean pulse wave velocity was 10.8 m/s, and 81.3% had abdominal aortic calcification at baseline. At 96 weeks, pulse wave velocity did not differ significantly between groups, nor did abdominal aortic calcification, serum phosphate, parathyroid hormone, FGF23, and 24-hour urinary phosphate. Serious adverse events occurred in 63 (46%) participants prescribed lanthanum and 66 (47%) prescribed placebo. Although recruitment to target was not achieved, additional analysis suggested this was unlikely to have significantly affected the principle findings.

CONCLUSIONS

In patients with stage 3b/4 CKD, treatment with lanthanum over 96 weeks did not affect arterial stiffness or aortic calcification compared with placebo. These findings do not support the role of intestinal phosphate binders to reduce cardiovascular risk in patients with CKD who have normophosphatemia.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Australian Clinical Trials Registry, ACTRN12610000650099.

Heart Failure With Preserved Ejection Fraction: A Comprehensive Review and Update of Diagnosis, Pathophysiology, Treatment, and Perioperative Implications

Almost three-quarters of all heart failure patients who are older than 65 have heart failure with preserved ejection fraction (HFpEF). The proportion and hospitalization rate of patients with HFpEF are increasing steadily relative to patients in whom heart failure occurs as result of reduced ejection fraction. The predominance of the HFpEF phenotype most likely is explained by the prevalence of medical conditions associated with an aging population. A multitude of age-related, medical, and lifestyle risk factors for HFpEF have been identified as potential causes for the sustained low-grade proinflammatory state that accelerates disease progression. Profound left ventricular (LV) systolic and diastolic stiffening, elevated LV filling pressures, reduced arterial compliance, left atrial hypertension, pulmonary venous congestion, and microvascular dysfunction characterize HFpEF, but pulmonary arterial hypertension, right ventricular dilation and dysfunction, and atrial fibrillation also frequently occur. These cardiovascular features make patients with HFpEF exquisitely sensitive to the development of hypotension in response to acute declines in LV preload or afterload that may occur during or after surgery. With the exception of symptom mitigation, lifestyle modifications, and rigorous control of comorbid conditions, few long-term treatment options exist for these unfortunate individuals. Patients with HFpEF present for surgery on a regular basis, and anesthesiologists need to be familiar with this heterogeneous and complex clinical syndrome to provide successful care. In this article, the authors review the diagnosis, pathophysiology, and treatment of HFpEF and also discuss its perioperative implications.

Vascular Decoupling in Septic Shock: The Combined Role of Autonomic Nervous System, Arterial Stiffness, and Peripheral Vascular Tone

BACKGROUND

Acute inflammation and sepsis are known to induce changes in vascular properties, leading to increased arterial stiffness; at the same time, the autonomic nervous system (ANS) also affects vascular properties by modulating the arterial smooth muscle tone, and it is widely reported that sepsis and septic shock severely impair ANS activity. Currently, clinical guidelines are mainly concerned to resuscitate septic shock patients from hypotension, hypovolemia, and hypoperfusion; however, if the current resuscitation maneuvers have a beneficial effect also on vascular properties and autonomic functionality is still unclear. The objective of this work is to assess the effects of standard resuscitation at vascular level and to verify if there is any association between alterations in vascular properties and ANS activity.

METHODS

Six pigs underwent a protocol of polymicrobial septic shock and resuscitation (fluids and noradrenaline). The arterial blood pressure (ABP) waveform was recorded in the central aorta and in the peripheral radial and femoral artery. The characteristic arterial time constant was computed at the three arterial sites based on the two-element Windkessel model, to characterize the overall arterial vascular tree. Moreover, independent estimates of total arterial compliance (AC) and total peripheral resistance (TPR) were performed. Baroreflex sensitivity (BRS), low frequency (LF, 0.04-0.15 Hz) spectral power of diastolic blood pressure, and indices of heart rate variability (HRV) were computed to assess ANS functionality.

RESULTS

Septic shock induced a severe vascular disarray, decoupling the usual pressure wave propagation from central to peripheral sites; this phenomenon appeared as an inversion of the physiological pulse pressure (PP) amplification, with a higher PP in the central aorta than in the peripheral arteries. The time constant was decreased, together with AC and TPR. ANS dysfunction was described by a reduced BRS, decreased LF power, and suppressed HRV. This compromised condition was not resolved by administration of fluids and noradrenaline. Thus, a persistent vascular and autonomic dysfunction were reported also in the resuscitated animals, and they were found to be significantly correlated.

CONCLUSION

Measures of vascular function and ANS activity could add information to standard hemodynamic and clinical markers, and the current resuscitation strategies could benefit from the adjunction of these additional functional indices.

Formulas to Explain Popular Oscillometric Blood Pressure Estimation Algorithms

Oscillometry is the blood pressure (BP) measurement principle of most automatic cuff devices. The oscillogram (which is approximately the blood volume oscillation amplitude-external pressure function) is measured, and BP is then estimated via an empirical algorithm. The objective was to establish formulas to explain three popular empirical algorithms in the literature—the maximum amplitude, derivative, and fixed ratio algorithms. A mathematical model of the oscillogram was developed and analyzed to derive parametric formulas for explaining each algorithm. Exemplary parameter values were obtained by fitting the model to measured oscillograms. The model and formulas were validated by showing that their predictions correspond to measurements. The formula for the maximum amplitude algorithm indicates that it yields a weighted average of systolic and diastolic BP (0.45 and 0.55 weighting) instead of commonly assumed mean BP. The formulas for the derivative algorithm indicate that it can accurately estimate systolic and diastolic BP (<1.5 mmHg error), if oscillogram measurement noise can be obviated. The formulas for the fixed ratio algorithm indicate that it can yield inaccurate BP estimates, because the ratios change substantially (over a 0.5–0.6 range) with arterial compliance and pulse pressure and error in the assumed ratio translates to BP error via large amplification (>40). The established formulas allow for easy and complete interpretation of perhaps the three most popular oscillometric BP estimation algorithms in the literature while providing new insights. The model and formulas may also be of some value toward improving the accuracy of automatic cuff BP measurement devices.

Evaluation of the calculation formulas of the cardio-ankle vascular index used in the Japanese apparatus

Background

Recently, coefficients in the equation of cardio-ankle vascular index (CAVI) used in VaSera^® device were disclosed. This study aimed to simulate the influence of adjusting the coefficients in the equation of CAVI and also aimed to validate the equation.

Methods

The CAVI displayed by VaSera (CAVIvs) and the CAVI estimated (CAVIes) with fixing the coefficients of the middle range of the heart-ankle stiffness parameter β (haβ) in the equation were compared. Moreover, the heart-ankle pulse wave velocity (haPWV) which corresponds to the low cutoff haβ of 7.348 was estimated in various blood pressure patterns to validate the formula.

Results

The CAVIvs was clearly lower than CAVIes in the low and the high range of CAVIvs. Moreover, it was virtually impossible to obtain the low cutoff haβ of 7.348 by using typical values of haPWV.

Conclusion

The CAVIvs in the high-range of VaSera underestimates the original property of stiffness parameter β. Moreover, there will be also a missing information in the equations introduced in the corresponding article, especially in the calculation formula of CAVIvs from haβ. Therefore, in order to make the best use of the nature of the stiffness parameter β to be used in VaSera, fixing the coefficients or termination of its use should be considered.

Acute Blood Pressure and Cardiovascular Effects of Near-Roadway Exposures With and Without N95 Respirators

BACKGROUND

The risk for cardiovascular events increases within hours of near-roadway exposures. We aimed to determine the traffic-related air pollution (TRAP) and biological mechanisms involved and if reducing particulate matter <2.5 µm (PM2.5) inhalation is protective.

METHODS

Fifty healthy-adults underwent multiple 2-hour near-roadway exposures (Tuesdays to Fridays) in Ann Arbor during 2 separate weeks (randomized to wear an N95 respirator during 1 week). Monday both weeks, participants rested 2 hours in an exam room (once wearing an N95 respirator). Brachial blood pressure, aortic hemodynamics, and heart rate variability were repeatedly measured during exposures. Endothelial function (reactive hyperemia index [RHI]) was measured post-exposures (Thursdays). Black carbon (BC), total particle count (PC), PM2.5, noise and temperature were measured throughout exposures.

RESULTS

PM2.5 (9.3 ± 7.7 µg/m3), BC (1.3 ± 0.6 µg/m3), PC (8,375 ± 4,930 particles/cm3) and noise (69.2 ± 4.2 dB) were higher (P values <0.01) and aortic hemodynamic parameters trended worse while near-roadway (P values<0.15 vs. exam room). Other outcomes were unchanged. Aortic hemodynamics trended towards improvements with N95 respirator usage while near-roadway (P values<0.15 vs. no-use), whereas other outcomes remained unaffected. Higher near-roadway PC and BC exposures were associated with increases in aortic augmentation pressures (P values<0.05) and trends toward lower RHI (P values <0.2). N95 respirator usage did not mitigate these adverse responses (nonsignificant pollutant-respirator interactions). Near-roadway outdoor-temperature and noise were also associated with cardiovascular changes.

CONCLUSIONS

Exposure to real-world combustion-derived particulates in TRAP, even at relatively low concentrations, acutely worsened aortic hemodynamics. Our mixed findings regarding the health benefits of wearing N95 respirators support that further studies are needed to validate if they adequately protect against TRAP given their growing worldwide usage.

Burden of Cardiovascular Risk Factors Over Time and Arterial Stiffness in Youth With Type 1 Diabetes Mellitus: The SEARCH for Diabetes in Youth Study

Background The incidence of type 1 diabetes mellitus (T1DM) in children is increasing, resulting in higher burden of cardiovascular diseases due to diabetes mellitus-related vascular dysfunction. Methods and Results We examined cardiovascular risk factors ( CVRF s) and arterial parameters in 1809 youth with T1DM. Demographics, anthropometrics, blood pressure, and laboratory data were collected at T1DM onset and 5 years later. Pulse wave velocity and augmentation index were collected with tonometry. ANOVA or chi-square tests were used to test for differences in measures of arterial parameters by CVRF . Area under the curve of CVRF s was entered in general linear models to explore determinants of accelerate vascular aging. Participants at the time of arterial measurement were 17.6±4.5 years old, 50% female, 76% non-Hispanic white, and duration of T1DM was 7.8±1.9 years. Glycemic control was poor (glycated hemoglobin, 9.1±1.8%). All arterial parameters were higher in participants with glycated hemoglobin ≥9% and pulse wave velocity was higher with lower insulin sensitivity or longer duration of diabetes mellitus. Differences in arterial parameters were found by sex, age, and presence of obesity, hypertension, or dyslipidemia. In multivariable models, higher glycated hemoglobin, lower insulin sensitivity, body mass index, blood pressure, and lipid areas under the curve were associated with accelerated vascular aging. Conclusions In young people with T1DM, persistent poor glycemic control and higher levels of traditional CVRF s are independently associated with arterial aging. Improving glycemic control and interventions to lower CVRF s may prevent future cardiovascular events in young individuals with T1DM.

Arterial stiffness during whole-body passive heat stress in healthy older adults

We tested the hypothesis that whole-body passive heat stress reduces arterial stiffness in older adults. At preheat stress (baseline) and when core temperature was elevated by 0.6 ± 0.2°C (mild) and 1.2 ± 0.3°C (moderate), arterial stiffness was measured in eight healthy younger (26 ± 5 years) and eight healthy older (70 ± 4 years) adults in the supine position. Arterial stiffness was estimated from carotid-to-femoral pulse wave velocity (cfPWV, applanation tonometry). cfPWV was higher at baseline in older adults (8.8 ± 2.3 m/sec vs. 5.6 ± 0.9 m/sec, P < 0.01) and this difference was maintained throughout passive heat stress (P < 0.01). cfPWV did not change (P ≥ 0.49) with passive heat stress in either younger (at moderate heat stress: 6.0 ± 1.0 m/sec) or older (at moderate heat stress: 8.5 ± 1.6 m/sec) adults. However, the influence of baseline cfPWV on the change in cfPWV during mild (r = -0.66, P = 0.04) and moderate (r = -0.87, P < 0.01) heat stress were inversely related in older adults, and the strength of these relations was not statistically different (P = 0.08). In younger adults, the influence of baseline cfPWV on the change in cfPWV during mild heat stress was also inversely related (r = -0.79, P = 0.01), while the strength of this relation was attenuated at moderate heat stress (r = -0.24, P = 0.30). Changes in arterial stiffness during passive heat stress in adults aged ≥65 year are likely dependent on the magnitude of baseline arterial stiffness and not necessarily age.

Aortic Pulsatility Propagates Intracranially and Correlates with Dilated Perivascular Spaces and Small Vessel Compliance

INTRODUCTION

To test the hypotheses that changes in the aortic pulse-wave produced by arterial stiffening are (1) propagated into cerebral small vessels, (2) associated with reduced compliance of small cerebral arterial vessels, and (3) associated with the presence of dilated perivascular spaces (PVS).

METHODS

Fifteen volunteers and 19 patients with late-onset depression (LOD) were prospectively recruited, of which 6 fulfilled the criteria for treatment-resistant depression (TRD). Aortic pulse-wave velocity (PWV) was determined using Carotid-Femoral Doppler. Pulse-wave analysis (PWA) was performed using a SphygmoCor system. White-matter lesion load and PVS were scored on established MRI scales. Cerebral arterial and aqueductal cerebrospinal fluid (CSF) flow patterns were studied using quantitative phase-contrast angiography.

RESULTS

Depressed patients had more PVS (P < .05) and prolongation of the width of the arterial systolic pulse-wave in the carotid arteries (P < .01). There was no significant group difference for any PWV or PWA measurement. TRD patients showed more PVS than other LOD patients (P < .05). The fractional width of the arterial systolic peak correlated significantly with augmentation index (AIx) and heart rate-corrected augmentation index (AIx75; R² = 0.302, P < .01and R² = 0.363, P < .01 respectively). Arterial-aqueductal delay showed a negative correlation with estimated aortic systolic pressure (PWVsys; R² =  0.293; P < .01), AIx (R² = -0.491; P < .01) and AIx75 (R² = -0.310; P < .01). PVS scores correlated with AIx (R² = 0.485; P < .01) and AIx75 (R² = -0.292; P < .01).

CONCLUSION

Our findings support the hypothesis that increased arterial pulsatility resulting from central arterial stiffness propagates directly into cerebral vessels and is associated with the development of microvascular angiopathy, characterized by dilated PVS and decreased compliance of small arterial vessels.

Reducing lung liquid volume increases biventricular outputs and systemic arterial blood flows despite decreased cardiac filling pressures in fetal lambs

As prior work has shown that reducing lung liquid volume 1) increases pulmonary arterial (PA) blood flow, 2) augments right ventricular (RV) output/power, and 3) decreases left atrial (LA) pressure, we tested the hypothesis that this perturbation has global cardiovascular effects. Ten anesthetized, open-chest fetal lambs (128 ± 2 days gestation, full term = 147 days) were acutely instrumented with 1) LA and right atrial (RA) catheters, 2) aortic and pulmonary trunk catheters, 3) brachiocephalic trunk, aortic isthmus, ductal, and left PA flow probes to obtain left ventricular (LV) and RV outputs and hydraulic power and flow in the descending thoracic aorta, and 4) an endotracheal tube to remove lung liquid. A 17 ± 7 ml/kg reduction of lung liquid volume 1) decreased LA and RA pressures similarly (1.5-1.6 mmHg, P < 0.001), 2) augmented LV and RV outputs (21-24%, P < 0.001) and total power (27-28%, P < 0.005), 3) increased systolic flows in the brachiocephalic trunk (18%, P < 0.001), aortic isthmus (29%, P < 0.005), ductus (12%, P < 0.005), and descending thoracic aorta (16%, P < 0.001), 4) increased mean PA flow via a higher systolic inflow (37%, P < 0.001) and lower diastolic backflow (-16%, P < 0.05), and 5) did not change systemic vascular conductance or arterial compliance but increased both pulmonary vascular conductance and arterial compliance (1.8-fold, P < 0.001). These data suggest that hemodynamic effects of lung liquid volume reduction are not confined to the lungs but extend to all cardiac chambers via rises in LV and RV outputs and power, despite falls in cardiac filling pressures, as well as the systemic circulation, via downstream increases in systolic flows of major central arteries.

Hypertension and transcatheter aortic valve replacement: parallel or series?

Aortic stenosis (AS) is the most common valvular heart disease in the elderly and it causes significant morbidity and mortality. Hypertension is also highly prevalent in elderly patients with AS, and AS patients with hypertension have worse outcomes. Accurate assessment of AS severity and understanding its relationship with arterial compliance has become increasingly important as the options for valve management, particularly transcatheter interventions, have grown. The parameters used for quantifying stenosis severity have traditionally mainly focused on the valve itself. However, AS is now recognized as a systemic disease involving aging ventricles and stiff arteries rather than one limited solely to the valve. Over the last decade, valvuloarterial impedance, a measure of global ventricular load, has contributed to our understanding of the pathophysiology and course of AS in heterogeneous patients, even when segregated by symptoms and severity. This review summarizes our growing understanding of the interplay between ventricle, valve, and vessel, with a particular emphasis on downstream vascular changes after transcatheter aortic valve replacement and the role of valvuloarterial impedance in predicting left ventricular changes and prognosis in patients with various transvalvular flow patterns.

Arterial stiffness and subclinical aortic damage of reclassified subjects as stage 1 hypertension according to the new 2017 ACC/AHA blood pressure guidelines

Background: The 2017 ACC/AHA blood pressure (BP) guidelines generated controversies due to the new proposed BP cut-off values defining hypertension. We aimed to assess aortic stiffness of subjects who are reclassified as stage 1 hypertensive according to the new guidelines and compare them with the subjects of "elevated BP" category. Patients and methods. Data from the "Corinthia" study, an observational, cross-sectional survey of 2,043 participants were analyzed. Subjects were classified into 4 groups: group A: systolic pressure (SBP) 120-129 and diastolic pressure (DBP) < 80 mmHg, group B: SBP 130-139 or DBP 80-89 mmHg, group B1: SBP 130-139 and DBP < 80 mmHg and group B2: SBP 130-139 and DBP 80-89 mmHg. Aortic stiffness was assessed by carotid-to-femoral pulse wave velocity (PWV). A value of PWV > 10m/s was consider indicative of asymptomatic organ damage while values of PWV exceeded the 90 % percentile for each age group were consider as abnormal. Results: Groups B, B1 and B2 have significantly increased PWV compared to group A, independently from age and other risk factors (PWV: 9.2 ± 2.8 vs 9.4 ± 2.7 vs 8.6 ± 2.5 vs 8.1 ± 2.3 m/s, p < 0.01, respectively). The prevalence of PWV > 10 m/s and abnormal PWV values in group A was significantly lower than the corresponding prevalence in randomly selected, age-matched subjects from group B (13.5 % vs 24.4 %, p = 0.027 and 5.6 % vs 14.2 %, p = 0.022, respectively). Conclusions: The reclassified subjects as stage 1 hypertensive by the new guidelines have a significantly increased aortic stiffness and greater prevalence in asymptomatic aortic damage compared to subjects with elevated BP. This finding may indirectly explain the increased cardiovascular risk of this group.

Disconnection of pulmonary and systemic arterial stiffness in COPD

Background

Both pulmonary arterial stiffening and systemic arterial stiffening have been described in COPD. The aim of the current study was to assess pulse wave velocity (PWV) within these two arterial beds to determine whether they are separate or linked processes.

Materials and methods

In total, 58 participants with COPD and 21 healthy volunteers (HVs) underwent cardiac magnetic resonance imaging (MRI) and were tested with a panel of relevant biomarkers. Cardiac MRI was used to quantify ventricular mass, volumes, and pulmonary (pulse wave velocity [pPWV] and systemic pulse wave velocity [sPWV]).

Results

Those with COPD had higher pPWV (COPD: 2.62 vs HV: 1.78 ms⁻¹, p=0.006), higher right ventricular mass/volume ratio (RVMVR; COPD: 0.29 vs HV: 0.25 g/mL, p=0.012), higher left ventricular mass/volume ratio (LVMVR; COPD: 0.78 vs HV: 0.70 g/mL, p=0.009), and a trend toward a higher sPWV (COPD: 8.7 vs HV: 7.4 ms⁻¹, p=0.06). Multiple biomarkers were elevated: interleukin-6 (COPD: 1.38 vs HV: 0.58 pg/mL, p=0.02), high-sensitivity C-reactive protein (COPD: 6.42 vs HV: 2.49 mg/L, p=0.002), surfactant protein D (COPD: 16.9 vs HV: 9.13 ng/mL, p=0.001), N-terminal pro-brain natriuretic peptide (COPD: 603 vs HV: 198 pg/mL, p=0.001), and high-sensitivity troponin I (COPD: 2.27 vs HV: 0.92 pg/mL, p<0.001). There was a significant relationship between sPWV and LVMVR (p=0.01) but not pPWV (p=0.97) nor between pPWV and RVMVR (p=0.27).

Conclusion

Pulmonary arterial stiffening and systemic arterial stiffening appear to be disconnected and should therefore be considered independent processes in COPD. Further work is warranted to determine whether both these cause an increased morbidity and mortality and whether both can be targeted by similar pharmacological therapy or whether different strategies are required for each.

The role of increased glucose on neurovascular dysfunction in patients with the metabolic syndrome

Metabolic syndrome (MetS) causes autonomic alteration and vascular dysfunction. The authors investigated whether impaired fasting glucose (IFG) is the main cause of vascular dysfunction via elevated sympathetic tone in nondiabetic patients with MetS. Pulse wave velocity, muscle sympathetic nerve activity (MSNA), and forearm vascular resistance was measured in patients with MetS divided according to fasting glucose levels: (1) MetS+IFG (blood glucose ≥100 mg/dL) and (2) MetS-IFG (<100 mg/dL) compared with healthy controls. Patients with MetS+IFG had higher pulse wave velocity than patients with MetS-IFG and controls (median 8.0 [interquartile range, 7.2-8.6], 7.3 [interquartile range, 6.9-7.9], and 6.9 [interquartile range, 6.6-7.2] m/s, P=.001). Patients with MetS+IFG had higher MSNA than patients with MetS-IFG and controls, and patients with MetS-IFG had higher MSNA than controls (31±1, 26±1, and 19±1 bursts per minute; P<.001). Patients with MetS+IFG were similar to patients with MetS-IFG but had higher forearm vascular resistance than controls (P=.008). IFG was the only predictor variable of MSNA. MSNA was associated with pulse wave velocity (R=.39, P=.002) and forearm vascular resistance (R=.30, P=.034). In patients with MetS, increased plasma glucose levels leads to an adrenergic burden that can explain vascular dysfunction.

Impact of Vascular Hemodynamics on Aortic Stenosis Evaluation: New Insights Into the Pathophysiology of Normal Flow-Small Aortic Valve Area-Low Gradient Pattern

Background

About 50% of normal‐flow/low‐gradient patients (ie, low mean gradient [MG] or peak aortic jet velocity and small aortic valve area) have severe aortic valve calcification as measured by computed tomography. However, they are considered to have moderate aortic stenosis (AS) in current American College of Cardiology/American Heart Association guidelines. The objective was thus to evaluate the effect of hypertension and reduced arterial compliance (rAC) on MG and V_peak measurements.

Methods and Results

Doppler‐echocardiography was performed in 4 sheep with experimentally induced severe and critical AS at: (1) normal aortic pressure, (2) during hypertension, and (3) with rAC. Hypertension and rAC induced a substantial decrease in MG/V_peak compared with normal stage (both P≤0.03) despite a stable transvalvular flow (P>0.16). Hypertension and rAC resulted in a greater reduction of MG in critical (−42%) compared with severe (−35%) AS (P˂0.0001). Comprehensive Doppler‐echocardiography and computed tomography were performed in 220 AS patients (mean age: 69±13 years; MG 29±18 mm Hg) with normal flow. The population was divided in 3 groups according to the presence of hypertension and rAC. The slope of the linear association between MG/V_peak and aortic valve calcification divided by the cross‐sectional area of the aortic annulus was significantly reduced in patients with hypertension and/or rAC compared with normotensive/normal AC patients (P<0.01). Accordingly, patients with normal‐flow/low‐gradient and severe aortic valve calcification density were more frequent in hypertension and rAC groups compared with the normotensive/normal‐AC group (16% and 12% compared with 2%; P=0.03).

Conclusions

Hypertension and rAC are associated with a substantial reduction in MG/V_peak for similar aortic valve calcification (ie, similar AS anatomic severity), which may lead to underestimation of AS hemodynamic severity.

Arteriosclerosis in the ventral aorta and epicarditis in the bulbus arteriosus of Atlantic salmon (Salmo salar L)

Spontaneous mortality of seemingly healthy, farmed Atlantic salmon (Salmo salar L) is an increasing problem in Norwegian aquaculture. In this study, we present a morphological study of the previously undescribed syndrome of arteriosclerosis of the ventral aorta and epicarditis of the adjacent bulbus arteriosus found in farmed Atlantic salmon, with wild-captured fish as a control group. Both the ventral aorta and epicardium are vital for correct arterial compliance and vascular resistance in the respiratory capillaries of the gills. We discuss the possible implications of ventral aorta arteriosclerosis and epicarditis for blood vascular health and in particular for the increasing frequency of spontaneous gill bleeding in farmed salmon. As both these conditions primarily occur in farmed salmon, we suggest that they should be considered pathological.

Interrelationships Among Various Measures of Central Artery Stiffness

BACKGROUND

A number of different techniques and methodologies have been applied to quantify stiffness of arteries. Because measures of arterial stiffness differ in regards to measurement locations as well as properties, it is not clear how well these measures that are supposed to reflect the same arterial wall properties are related.

METHODS

Interrelationships between different measures of arterial stiffness were evaluated in 50 apparently healthy subjects varying in age.

RESULTS

Significant relations ranging from mild to strong were observed among measures of arterial stiffness while some measures were not significantly associated. Cardio-ankle vascular index (CAVI) was significantly associated with carotid-femoral pulse wave velocity (cfPWV) and brachial-ankle pulse wave velocity (baPWV). Ultrasound-derived measures of arterial stiffness (e.g., compliance, distensibility) were weakly or not significantly related to pulse wave velocity (PWV) measures. The limits of agreement between each of arterial stiffness measures based on the Bland-Altman analyses indicate that there were close agreements (CI = 1.12-1.52) between CAVI, cfPWV, and baPWV. However, agreements between PWV measures and ultrasound-derived measures were mild to moderate. β-stiffness index demonstrated large 95% CIs with other measures. When associations between relative changes in various measures of arterial stiffness in response to isometric handgrip exercise were evaluated, the general trend of associations was similar to the relations observed at rest. β-stiffness index was not related to most measures of arterial stiffness.

CONCLUSION

These results suggest that the techniques used to assess arterial stiffness may not be interchangeable in clinical and research settings and that comparisons of findings obtained with different arterial stiffness measures should be conducted with caution.

Comparison of High-Protein, Intermittent Fasting Low-Calorie Diet and Heart Healthy Diet for Vascular Health of the Obese

AIM

It has been debated whether different diets are more or less effective in long-term weight loss success and cardiovascular disease prevention among men and women. To further explore these questions, the present study evaluated the combined effects of a high-protein, intermittent fasting, low-calorie diet plan compared with a heart healthy diet plan during weight loss, and weight loss maintenance on blood lipids and vascular compliance of obese individuals.

METHODS

The experiment involved 40 obese adults (men, n = 21; women, n = 19) and was divided into two phases: (a) 12-week high-protein, intermittent fasting, low-calorie weight loss diet comparing men and women (Phase 1) and (b) a 1-year weight maintenance phase comparing high-protein, intermittent fasting with a heart healthy diet (Phase 2). Body weight, body mass index (BMI), blood lipids, and arterial compliance outcomes were assessed at weeks 1 (baseline control), 12 (weight loss), and 64 (12 + 52 week; weight loss maintenance).

RESULTS

At the end of weight loss intervention, concomitant reductions in body weight, BMI and blood lipids were observed, as well as enhanced arterial compliance. No sex-specific differences in responses were observed. During phase 2, the high-protein, intermittent fasting group demonstrated a trend for less regain in BMI, low-density lipoprotein (LDL), and aortic pulse wave velocity than the heart healthy group.

CONCLUSION

Our results suggest that a high-protein, intermittent fasting and low-calorie diet is associated with similar reductions in BMI and blood lipids in obese men and women. This diet also demonstrated an advantage in minimizing weight regain as well as enhancing arterial compliance as compared to a heart healthy diet after 1 year.

Antihypertensive treatment decreases arterial stiffness at night but not during the day. Results from the Hypertension in the Very Elderly Trial

The main Hypertension in the Very Elderly Trial (HYVET) demonstrated a very marked reduction in cardiovascular events by treating hypertensive participants 80 years or older with a low dose, sustained release prescription of indapamide (indapamide SR, 1.5 mg) to which was added a low dose of an angiotensin converting enzyme inhibitor in two-thirds of cases (perindopril 2-4 mg). This report from the ambulatory blood pressure sub-study investigates whether changes in arterial stiffness and ambulatory blood pressure (BP) could both explain the benefits observed in the main trial. A total of 139 participants were randomized to placebo [67] and to active treatment [72] and had both day and night observations of BP and arterial stiffness as determined from the Q wave Korotkoff diastolic (QKD) interval. The QKD interval was 5.6 ms longer (p = 0.017) in the actively treated group at night than in the placebo group. This was not true for the more numerous daytime readings so that 24-h results were similar in the two groups. The QKD interval remained longer at night in the actively treated group even when adjusted for systolic pressure, heart rate and height. The reduced arterial stiffness at night may partly explain the marked benefits observed in the main trial.

A guide to uncertainty quantification and sensitivity analysis for cardiovascular applications

As we shift from population-based medicine towards a more precise patient-specific regime guided by predictions of verified and well-established cardiovascular models, an urgent question arises: how sensitive are the model predictions to errors and uncertainties in the model inputs? To make our models suitable for clinical decision-making, precise knowledge of prediction reliability is of paramount importance. Efficient and practical methods for uncertainty quantification (UQ) and sensitivity analysis (SA) are therefore essential. In this work, we explain the concepts of global UQ and global, variance-based SA along with two often-used methods that are applicable to any model without requiring model implementation changes: Monte Carlo (MC) and polynomial chaos (PC). Furthermore, we propose a guide for UQ and SA according to a six-step procedure and demonstrate it for two clinically relevant cardiovascular models: model-based estimation of the fractional flow reserve (FFR) and model-based estimation of the total arterial compliance (CT ). Both MC and PC produce identical results and may be used interchangeably to identify most significant model inputs with respect to uncertainty in model predictions of FFR and CT . However, PC is more cost-efficient as it requires an order of magnitude fewer model evaluations than MC. Additionally, we demonstrate that targeted reduction of uncertainty in the most significant model inputs reduces the uncertainty in the model predictions efficiently. In conclusion, this article offers a practical guide to UQ and SA to help move the clinical application of mathematical models forward. Copyright © 2015 John Wiley & Sons, Ltd.

Arterial stiffness of lifelong Japanese female pearl divers

Japanese female pearl divers called Ama specialize in free diving in the cold sea for collecting foods and pearls in oysters. Exercising in the water combined with marked bradycardia and pressor responses provides a circulatory challenge to properly buffer or cushion elevated cardiac pulsations. Because Ama perform repeated free dives throughout their lives, it is possible that they may have adapted similar arterial structure and function to those seen in diving mammals. We compared arterial stiffness of lifelong Japanese pearl divers with age-matched physically inactive adults living in the same fishing villages. A total of 115 Japanese female pearl divers were studied. Additionally, 50 physically inactive adults as well as 33 physically active adults (participating in community fitness programs) living in the same coastal villages were also studied. There were no differences in age (∼65 yr), body mass index, and brachial blood pressure between the groups. Measures of arterial stiffness, cardio-ankle vascular index and β-stiffness index were lower (P < 0.05) in pearl divers and physically active adults than in their physically inactive peers. Augmentation pressure and augmentation index adjusted for the heart rate of 75 beats/min were lower (P < 0.05) in pearl divers than in other groups. These results indicate that lifelong Japanese pearl divers demonstrate reduced arterial stiffness and arterial wave reflection compared with age-matched physically inactive peers living in the same fishing villages.

The acute effect of maximal exercise on central and peripheral arterial stiffness indices and hemodynamics in children and adults

This study compared the effects of a bout of maximal running exercise on arterial stiffness in children and adults. Right carotid blood pressure and artery stiffness indices measured by pulse wave velocity (PWV), compliance and distensibility coefficients, stiffness index α and β (echo-tracking), contralateral carotid blood pressure, and upper and lower limb and central/aortic PWV (applanation tonometry) were taken at rest and 10 min after a bout of maximal treadmill running in 34 children (7.38 ± 0.38 years) and 45 young adults (25.22 ± 0.91 years) having similar aerobic potential. Two-by-two repeated measures analysis of variance and analysis of covariance were used to detect differences with exercise between groups. Carotid pulse pressure (PP; η(2) = 0.394) increased more in adults after exercise (p < 0.05). Compliance (η(2) = 0.385) decreased in particular in adults and in those with high changes in distending pressure, similarly to stiffness index α and β. Carotid PWV increased more in adults and was related to local changes in PP but not mean arterial pressure (MAP). Stiffness in the lower limbs decreased (η(2) = 0.115) but apparently only in those with small MAP changes (η(2) = 0.111). No significant exercise or group interaction effects were found when variables were adjusted to height. An acute bout of maximal exercise can alter arterial stiffness and hemodynamics in the carotid artery and within the active muscle beds. Arterial stiffness and hemodynamic response to metabolic demands during exercise in children simply reflect their smaller body size and may not indicate a particular physiological difference compared with adults.

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.

Left Ventricle-Arterial System Interaction in Heart Failure

Ejection fraction (EF) has been viewed as an important index in assessing the contractile state of the left ventricle (LV). However, it is frequently inadequate for the diagnosis and management of heart failure (HF), as a significant subset of HF patients have been found to have reduced EF (HFrEF) whereas others have preserved EF (HFpEF). It should be noted that the function of the LV is dependent on both preload and afterload, as well as its intrinsic contractile state. Furthermore, stroke volume (SV) is dependent on the properties of the arterial system (AS). Thus, the LV-arterial system interaction plays an important role in those patients with HF. This aspect is investigated through the analysis of the specific parameters involved in the coupling of the LV and AS. This includes contractility and the systolic/diastolic indices of the LV. Furthermore, AS afterload parameters such as vascular stiffness and arterial compliance, and their derived coupling coefficient, are also investigated. We conclude that those parameters, which relate to LV structural changes, are most appropriate in quantifying the LV-AS interaction.

Noninvasive assessment of arterial compliance of human cerebral arteries with short inversion time arterial spin labeling

A noninvasive method of assessing cerebral arterial compliance (AC) is introduced in which arterial spin labeling (ASL) is used to measure changes in arterial blood volume (aBV) occurring within the cardiac cycle. Short inversion time pulsed ASL (PASL) was performed in healthy volunteers with inversion times ranging from 250 to 850 ms. A model of the arterial input function was used to obtain the cerebral aBV. Results indicate that aBV depends on the cardiac phase of the arteries in the imaging volume. Cerebral AC, estimated from aBV and brachial blood pressure measured noninvasively in systole and diastole, was assessed in the flow territories of the basal cerebral arteries originating from the circle of Willis: right and left middle cerebral arteries (RMCA and LMCA), right and left posterior cerebral arteries (RPCA and LPCA), and the anterior cerebral artery (ACA). Group average AC values calculated for the RMCA, LMCA, ACA, RPCA, and LPCA were 0.56%±0.2%, 0.50%±0.3%, 0.4%±0.2%, 1.1%±0.5%, and 1.1%±0.3% per mm Hg, respectively. The current experiment has shown the feasibility of measuring AC of cerebral arteries with short inversion time PASL.

Associations between echocardiographic arterial compliance and incident cardiovascular disease in blacks: the ARIC study

BACKGROUND

Systemic arterial compliance is sometimes derived by echocardiographic stroke volume to pulse pressure ratios. Few studies have assessed echocardiographic arterial compliance in blacks or its associations with explicit, rather than composite, cardiovascular disease (CVD) outcomes.

METHODS

We analyzed a subset (n = 1,887) of blacks (mean age = 59 ± 6 years; 65% women) in the Atherosclerosis Risk in Communities study who were free of prevalent CVD and were imaged by echocardiography in 1993-1995. Arterial compliance was calculated by the aortic velocity time integral and brachial pulse pressure ratio (VTI/PP). Associations between VTI/PP and subsequent CVD (defined as first incident stroke, coronary event, or heart failure) were modeled by Cox regression after controlling for demographics, anthropometry, and cardiac risk factors. For comparison, CVD hazard ratios were also calculated for pulse pressure quartiles.

RESULTS

Over a mean follow-up of 13 ± 4 years, 237 subjects (12%) developed coronary disease, 322 (16%) developed heart failure, and 180 (9%) experienced a stroke. Hazard ratios contrasting lowest with highest quartiles of VTI/PP were 2.3 (95% confidence interval (CI) = 1.7-3.1) for composite CVD, 2.1 (95% CI = 1.3-3.2) for coronary disease, 2.5 (95% CI = 1.7-3.6) for heart failure, and 2.7 (95% CI = 1.6-4.5) for stroke. Hazard ratios contrasting widest with narrowest pulse pressure quartiles were 1.7 (95% CI = 1.3-2.2) for composite CVD, 1.6 (95% CI = 1.0-2.4) for coronary heart disease, 1.8 (95% CI = 1.2-2.6) for heart failure, and 2.3 (95% CI = 1.3-3.9) for stroke.

CONCLUSIONS

In blacks, the VTI/PP ratio has stronger associations with both composite and individual CVD outcomes than does pulse pressure.

Arterial stiffness is inversely associated with a better running record in a full course marathon race

[Purpose]

Arterial stiffness is an independent predictor of cardiovascular risk and may contribute to reduced running capacity in humans. This study investigated the relationship between course record and arterial stiffness in marathoners who participated in the Seoul International Marathon in 2012.

[Methods]

A total of 30 amateur marathoners (Males n = 28, Females n = 2, mean age = 51.6 ± 8.3 years) were assessed before and after the marathon race. Brachial-ankle pulse wave velocity (ba-PWV) was assessed by VP-1000 plus (Omron Healthcare Co., Ltd., Kyoto, Japan) before and immediately after the marathon race. Pearson's correlation coefficient was used to determine the relationship between race record and ba-PWV. In addition, Wilcoxon signed rank test was used to determine the difference in ba-PWV between before and after the race.

[Results]

There was no significant change in the ba-PWV of marathoners before and after the race (1271.1 ± 185 vs. 1268.8 ± 200 cm/s, P=0.579). Both the full course record (Pearson's correlation coefficient = 0.416, P = 0.022) and the record of half line (Pearson's correlation coefficient = 0.482, P = 0.007) were positively related with the difference in ba-PWV, suggesting that reduced arterial stiffness is associated with a better running record in the marathon.

[Conclusion]

These results may suggest that good vascular function contributes to a better running record in the marathon race.