Changes In Arterial Compliance Research Articles

Spontaneous Bursts of Muscle Sympathetic Nerve Activity Reduce Femoral Arterial Compliance in Humans

Previous studies in rodents have demonstrated tonic sympathetic restraint of arterial compliance. To date, studies in humans have examined sympathetic restraint of compliance via either reflexively or pharmacologically manipulating sympathetic vasoconstriction and measuring resultant changes in compliance. The extent to which spontaneous bursts of muscle sympathetic nerve activity (MSNA) dynamically regulate arterial compliance in humans on a beat-by-beat basis remains unknown. Herein, we hypothesized that femoral arterial compliance would be transiently reduced following spontaneous bursts of MSNA. Further, we hypothesized that the magnitude of reduction in arterial compliance would be graded to the MSNA burst amplitude (index of net neural outflow). Beat-to-beat blood pressure (BP; Finometer), heart rate (ECG), MSNA (peroneal microneurography), and femoral artery blood flow (duplex Doppler ultrasound) were continuously measured over 10-20 minutes of quiet supine rest in 27 young, healthy men (age: 22 ± 1 years, resting MSNA burst frequency: 11 ± 5 bursts/minute). Customized labview programs were used to time-align neural cardiovascular variables with ultrasound data sampled at 30Hz, enabling the quantification of arterial compliance on a beat-by-beat basis defined as the change in arterial cross-sectional area divided by the change in blood pressure over the cardiac cycle. Bursts of MSNA were tracked for 10 cardiac cycles and changes in arterial compliance were quantified using signal-averaging for all bursts, and subsequently, for bursts of MSNA when sub-classified based on amplitude into quartiles (Q1= smallest 25% of bursts, Q4= largest 25% of bursts). Reductions in arterial compliance were significantly greater following cardiac cycles with bursts of MSNA compared to cardiac cycles without bursts of MSNA (bursts: -5.1 ± 0.6% vs. non-bursts: -0.8 ± 0.2%, p<0.001). Further, reductions in compliance appeared to be graded to MSNA burst amplitude (Q1: -6.5 ± 0.8%; Q4: -9.1 ± 1.3%, P=0.051). The latency (i.e., number of heartbeats) to nadir arterial compliance following bursts of MSNA was 4.2 ± 0.6 cardiac cycles. Collectively, these findings suggest that the sympathetic nervous system dynamically regulates femoral arterial compliance on a beat-to-beat basis. College of Nursing and Health Innovation, University of Texas at Arlington. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Adolescents and Young Adults with Type 1 Diabetes Present Changes in Arterial Compliance and Resistance and Increased Arterial Stiffness

Adolescents and Young Adults with Type 1 Diabetes Present Changes in Arterial Compliance and Resistance and Increased Arterial Stiffness

Fractional-Order Modeling of Arterial Compliance in Vascular Aging: A Computational Biomechanical Approach for Investigating Cardiovascular Dynamics.

Goal: The goal of this study is to investigate the application of fractional-order calculus in modeling arterial compliance in human vascular aging. Methods: A novel fractional-order modified arterial Windkessel model that incorporates a fractional-order capacitor (FOC) element is proposed to capture the complex and frequency-dependent properties of arterial compliance. The model's performance is evaluated by verifying it using data collected from three different human subjects, with a specific focus on aortic pressure and flow rates. Results: The results show that the FOC model accurately captures the dynamics of arterial compliance, providing a flexible means to estimate central blood pressure distribution and arterial stiffness. Conclusions: This study demonstrates the potential of fractional-order calculus in advancing the modeling and characterization of arterial compliance in human vascular aging. The proposed FOC model can improve our understanding of the physiological changes in arterial compliance associated with aging and help to identify potential interventions for age-related cardiovascular diseases.

Blood-pressure–waveform monitoring without interruptions due to changes in arterial compliance: The use of the vibrational and volume-clamp methods

The arterial–blood-pressure (ABP) waveform can be monitored by the volume-clamp method. The photoplethysmography (PPG) signal is measured and clamped at maximum arterial compliance (PPGcmax) by controlling the external pressure (EP) with a cuff. PPGcmax is determined by the volume-oscillometric method though ABP measurement is regularly interrupted. To overcome this drawback, the vibrational method superimposes high-frequency vibrations on EP and measures the PPG response to estimate the “vibrational” compliance (Cv) and the PPGcmax. This method, though, has never been validated or implemented simultaneously with the volume-clamp method because the control has always been unstable. We implemented a custom-made device with a novel control system, monitoring stability and adapting the gain at high frequencies, plus lower-amplitude EP vibrations. We compared, in eleven volunteers, the EP at PPGcmax determined by the volume-oscillometric and the vibrational methods. Both exhibited a good linear correlation (r2 >0.92) and Bland-Altman agreement (95% confidence interval <15 mmHg). Moreover, in three volunteers, the vibrational and volume-clamp methods were implemented together while experimentally changing the ABP and/or Cv without manifesting control-system instability. Cv measured with the vibrational method could be used by the volume-clamp method to measure the ABP waveform without any interruptions due to changes in arterial compliance.

Real-time embedded control for continuous measurement of blood pressure: methodologic innovations

Continuous blood-pressure (BP) waveform can be measured by the volume-clamp method, where a closed-loop control over a fast pneumatic actuator reproduces BP in a finger cuff. Frequent interruptions, however, are necessary to update arterial-wall compliance to a maximum. We implemented an embedded control in hard real time that measures BP without those interruptions. A microcontroller executes the control system at 2 ms while a computer asynchronously handles the most demanding tasks. The system's design included the following methodological innovations: 1) the arterial-compliance changes were estimated with high-frequency vibrations superimposed on the cuff pressure; 2) this information was used to update the control setpoint to maximum compliance, thus avoiding measurement interruptions; 3) the closed-loop stability was guaranteed with a recurrent redesign of the control; 4) the arterial-wall dynamics were identified for each subject in the control's design, thus improving the method's performance.

Cerebrovascular reactivity: a new frontier for measuring cognitive health in models of accelerated ageing?

Cerebrovascular reactivity: a new frontier for measuring cognitive health in models of accelerated ageing?

A modelling framework for assessment of arterial compliance by fusion of oscillometry and pulse wave velocity information

Background and ObjectivesMeasurement of arterial compliance is recognized as important for clinical use and for enabling better understanding of circulatory system regulation mechanisms. Estimation of arterial compliance involves either a direct measure of the ratio between arterial volume and pressure changes or an inference from the pulse wave velocity (PWV). In this study we demonstrate an approach to assess arterial compliance by fusion of these two information sources. The approach is based on combining oscillometry as used for blood pressure inference and PWV measurements based on ECG/PPG. Enabling reliable arterial compliance measurements will contribute to the understanding of regulation mechanisms of the arterial tree, possibly establishing arterial compliance as a key measure relevant in hemodynamic monitoring. MethodsA measurement strategy, a physiological model, and a framework based on Bayesian principles are developed for measuring changes in arterial compliance based on combining oscillometry and PWV data. A simulation framework is used to study and validate the algorithm and measurement principle in detail, motivated by previous experimental findings. ResultsSimulations demonstrate the possibility of inferring arterial compliance via fusion of simultaneously acquired volume/pressure relationships and PWV data. In addition, the simulation framework demonstrates how Bayesian principles can be used to handle low signal – to – noise ratio and partial information loss. ConclusionsThe developed simulation framework shows the feasibility of the proposed approach for assessment of arterial compliance by combining multiple data sources. This represents a first step towards integration of arterial compliance measurements in hemodynamic monitoring using existing clinical technology. The Bayesian approach is of particular relevance for such patient monitoring settings, where measurements are repeated frequently, context is relevant, and data is affected by artefacts. In addition, the simulation framework is necessary for future clinical-study design, in order to determine device specifications and the extent to which noise affects the inference process.

Tonometric and Oscillometric Methods for Measurement of Central Blood Pressure Parameters: a Comparison in Patients with Borderline Hypertension or Stage 1 Hypertension

Abstract Background Changes in arterial compliance are among the first changes detectable in hypertensive syndrome. Methods with good reproducibility as compared with the gold standard for identifying such changes are desirable in clinical practice. Objectives To compare central pressure measurements and arterial stiffness obtained by two non-invasive methods (tonometry and oscillometry). Methods This was a descriptive, cross-sectional study with a convenience sample of patients with borderline hypertension or stage 1 hypertension. Peripheral and central blood pressure measurements were obtained by tonometry (SphygmoCor®), considered the gold standard, and oscillometry (Mobil O´graph®). Comparisons of results were made by unpaired t-test, and p values 0.05). Mean pressure wave velocity (PWV), 8.4 m/s vs. 7.4 m/s (p = 0.013) and mean central pulse pressure, 37.7 mmmHg and 30.9 mmHg (p = 0.013) were significantly higher by SphygmoCor® than Mobil O´graph®. Conclusion Values of central systolic blood pressure, AIx and pulse pressure amplification obtained by oscillometry were not statistically different compared with tonometry; values of PWV and cPP, however, were underestimated by oscillometry. (Int J Cardiovasc Sci. 2020; 33(2):145-150)

Dietary modification reduces serum angiopoietin-like protein 2 levels and arterial stiffness in overweight and obese men.

Weight loss can reduce obesity-induced arterial stiffening that is attributed to decreased inflammation. Angiopoietin-like protein 2 (ANGPTL2) is a pro-inflammatory adipokine that is upregulated in obesity and is important in the progression of atherosclerosis and cardiovascular disease. The purpose of this study is to investigate the effects of dietary modification on circulating ANGPTL2 levels and arterial stiffness in overweight and obese men. Twenty-two overweight and obese men (with mean age of 56 ± 2 years and body mass index of 28.6 ± 2.6 kg/m2) completed a 12-week dietary modification program. We measured the arterial compliance and β-stiffness index (as the indices of arterial stiffness) and serum ANGPTL2 levels before and after the program. After the 12-week dietary modification, body mass and daily energy intake were significantly reduced. Arterial compliance was significantly increased and β-stiffness index was significantly decreased after the 12-week dietary modification program. Serum ANGPTL2 levels were significantly decreased. Also, the changes in arterial compliance were negatively correlated with the changes in serum ANGPTL2 levels, whereas the changes in β-stiffness index were positively correlated with the changes in serum ANGPTL2 levels. These results suggest that the decrease in circulating ANGPTL2 levels can be attributed to the dietary modification-induced reduction of arterial stiffness in overweight and obese men.

Can we IMPROVE cardiovascular outcomes through phosphate lowering in CKD? Rationale and protocol for the IMpact of Phosphate Reduction On Vascular End-points in Chronic Kidney Disease (IMPROVE-CKD) study

IntroductionPatients with chronic kidney disease (CKD) are at heightened cardiovascular risk, which has been associated with abnormalities of bone and mineral metabolism. A deeper understanding of these abnormalities should facilitate...

Etomidate-induced hypotension: a pathophysiological approach using arterial elastance

Introduction: Anaesthesia frequently induces hypotension. Several recent studies have analysed arterial elastance (Ea) in order to describe clinical variations of mean arterial pressure (MAP). The objective of the study was to assess Ea to explain MAP variation following etomidate induction.Methods: We conducted a prospective single-centre study. Inclusion criteria were patients undergoing elective cardiac surgery with invasive blood pressure monitoring. Ea was expressed as Pes/SV (Pes: end systolic pressure, SV: stroke volume). Cardiac index (CI), peripheral vascular resistance (PVR) and arterial compliance (C) was compared before and 2 minutes after etomidate induction. Arterial hypotension was defined as a decrease greater than 15% of the baseline MAP.Results: Of the 45 patients included, 24 (53%) had a preserved MAP and 21 (47%) had an etomidate-induced hypotension. Ea was similar before induction and decreased in the decreased MAP group 2 minutes after induction (2.0 mmHg.ml-1 [1.7-2.4] vs 1.4 mmHg.ml-1 [0.9-1.9]; p = 0.001). Arterial compliance (C) increased in the decreased MAP group 2 minutes after induction (0.8 ml. mmHg-1 [0.6-1.0] vs 0.5 ml. mmHg-1 [0.4-0.6], p < 0.0001). No significant change in CI or PVR was observed between patients with or without etomidate-induced hypotension.Conclusion: Etomidate-induced hypotension was associated to a decrease in Ea. Ea variations can mainly be explained by induced changes in arterial compliance.

Arterial stiffness in normal pregnancy as assessed by digital pulse wave analysis by photoplethysmography - A longitudinal study.

It might in the future be valuable to screen for increased maternal arterial stiffness, i.e. low compliance, since it is associated with development of hypertensive complications in pregnancy. Digital pulse wave analysis (DPA) is an easy and manageable method for arterial stiffness assessment. We aimed to investigate gestational influence on DPA variables longitudinally, and establish gestational age-adjusted reference values in normal pregnancy. DPA measurements were performed longitudinally up to five times during pregnancy in 139 healthy women. Reference curves for DPA variables aging index (AI), b/a and d/a relative to gestational age were calculated with linear and polynomial mixed-effects models, and the influences of age and parity investigated with analysis of variance and analysis of covariance. A p < 0.05 was regarded significant. All DPA variables were significantly associated with GA with best fit for a quadratic model. Arterial compliance peaked in the late second trimester. Age and parity independently influenced DPA variables but did not change the associations with gestational age. DPA reflects longitudinal changes in arterial compliance in normal pregnancy but individual variance of DPA changes were greater than the influence of GA. Normal distributions of AI, b/a and d/a at 14-24 weeks are presented, but it remains to show whether these can be used to detect pathological hemodynamic alterations in pregnancy.

Perioperative Noninvasive Blood Pressure Monitoring.

The most commonly monitored variable for perioperative hemodynamic management is blood pressure. Several indirect noninvasive blood pressure monitoring techniques have been developed over the last century, including intermittent techniques such as auscultation (Riva-Rocci and Korotkoff) and oscillometry (Marey) and continuous techniques. With the introduction of automated noninvasive blood pressure devices in the 1970s, the oscillometric technique quickly became and remains the standard for automated, intermittent blood pressure measurement. It tends to estimate more extreme high and low blood pressures closer to normal than what invasive measurements indicate. The accuracy of the oscillometric maximum amplitude algorithm for estimating mean arterial pressure is affected by multiple factors, including the cuff size and shape, the shape of the arterial compliance curve and arterial pressure pulse, and pulse pressure itself. Additionally, the technique typically assumes a consistent arterial compliance and arterial pressure pulse, thus changes in arterial compliance and arrhythmias that lead to variation in the pressure pulse can affect accuracy. Volume clamping, based on the Penaz principle, and arterial tonometry provide continuous tracking of the arterial pressure pulse. The ubiquitous use of blood pressure monitoring is in contrast with the lack of evidence for optimal perioperative blood pressure targets.

Cardiovascular Responses to Different Resistance Exercise Protocols in Elderly.

Increase in muscle mass and strength through resistance exercise (RE) has been highly recommended for healthy aging. On the other hand, RE could lead to acute cardiovascular risks prompted mainly by intense blood pressure elevations and cardiac autonomic imbalance. We compared the cardiovascular responses to three different RE protocols performed by 21 healthy elderly on a leg press machine. The protocols tested were high load (80% 1RM) until muscular failure (HL); low load (30% 1RM) until muscular failure (LL); low load, 30 repetitions followed by 3 sets of 15 repetitions, with 50% blood flow restriction (LL-BFR); and a control session (CON). Based on heart rate variability analysis, only LL kept parasympathetic indexes lower than CON at 30 min recovery. By finger photoplethysmography, LL-BFR prompted higher systolic and mainly diastolic blood pressure increments in many sets. The heart rate and cardiac output increase, and total peripheral resistance reduction following exercise were not different among RE protocols. There was no significant post-exercise hypotension and carotid arterial compliance changes. HL seems to be the safer protocol to be recommended for the healthy elderly, because it induces lower blood pressure increments and faster parasympathetic recovery compared to LL and LL-BFR.

Three-year change in endothelin-1 and markers of vascular remodelling in a bi-ethnic South African cohort: the SABPA study.

South Africans are at high risk for developing cardiovascular disease. Endothelin-1 is known for its vasoconstrictive properties and its ability to contribute to vascular structural changes. In this study we investigated the association of change in endothelin-1 levels and change in markers implicated in vascular remodelling after 3 years. Serum endothelin-1 levels and markers of vascular remodelling such as carotid intima-media thickness, carotid cross-sectional wall area (CSWA) and arterial compliance were measured. Participants were divided into two groups according to an increase (n=185) and a decrease (n=152) in plasma endothelin-1 levels after 3 years. In partial regression analysis, the extent of endothelin-1 increase correlated positively with a change in pulse pressure and inversely with the change in arterial compliance in the group with increased endothelin-1 levels after 3 years. In the group with decreased endothelin-1 levels, the extent of decreased endothelin-1 correlated inversely with a change in CSWA. In multiple regression analysis, after splitting for race, the increase in endothelin-1 levels associated positively with the change in pulse pressure (Adj. R2=0.092; β=0.278; P=0.036) in the black participants only. In conclusion, with increased endothelin-1 levels after 3 years, the positive association between endothelin-1 and pulse pressure suggest subclinical haemodynamic changes with potential premature onset of cardiovascular disease in the black participants.

Computational Modeling and Comparative Tissue Damage Analysis of Angioplasty and Orbital Atherectomy Interventional Procedures

This research was directed toward quantitatively characterizing the effects of arterial mechanical treatment procedures on the stress and strain energy states of the artery wall. Finite element simulations of percutaneous transluminal angioplasty (PTA) and orbital atherectomy (OA) were performed on arterial lesion models with various extents and types of plaque. Stress fields in the artery were calculated and strain energy density was used as an explicit description of potential damage to the artery. The research also included numerical simulations of changes in arterial compliance due to orbital atherectomy. The angioplasty simulations show that the damage energy fields in the media and adventitia are predominant in regions of the lesion that are not protected by a layer of calcification. In addition, it was observed that softening the plaque components leads to a lower peak stress and therefore lesser damage energy in the media and adventitia under the action of a semicompliant balloon. Orbital atherectomy simulations revealed that the major portion of strain energy dissipated is concentrated in the plaque components in contact with the spinning tool. The damage and peak stress fields in the media and adventitia components of the vessel were significantly less. This observation suggests less mechanically induced trauma during a localized procedure like orbital atherectomy. Artery compliance was calculated pre- and post-treatment and an increase was observed after the orbital atherectomy procedure. The localized plaque disruption produced in atherectomy suggests that the undesirable stress states in angioplasty can be mitigated by a combination of procedures such as atherectomy followed by angioplasty.

Calf Venous Compliance Differences in Male and Female Adults

Similar to changes in arterial compliance with fitness and aging, venous compliance in the lower extremities of adults improves with higher fitness and declines with increasing age. In young adults, males have a higher venous compliance than females, a difference that does not appear related to hormonal fluctuations. Most previous studies have used small groups to make these comparisons. PURPOSE: To determine the calf venous compliance differences in males and females in a larger group of adults. METHODS: 71 females and 102 males volunteered for this project. Participants underwent anthropometric assessment, a submaximal graded exercise test, and assessment of calf venous compliance. Utilizing venous occlusion plethysmography, calf pressure-volume relations were determined using the quadratic regression equation [(Δlimb volume) = β0 + β1*(cuff pressure) + β2*(cuff pressure)2]. Calf venous compliance was calculated as the first derivative of the pressure-volume relation during cuff pressure reduction. Sex differences in anthropometric variables, fitness, and compliance (β1, β2, and the slope of the pressure compliance relationship) were analyzed with a simple ANOVA. RESULTS: The males and females were of similar age [102 males (26 ± 12 yrs), 71 females (28 ± 17 yrs)] and fitness level (males 50.24 ± 19.55 ml*kg−1*min−1 vs. females 47.84 ± 16.03 ml*kg−1*min−1). The males were larger in size (BMI: 25.07 ± 3.81 kg/m2; calf volume: 585.79 ± 116.70 cm) than the females (BMI: 23.78 ± 4.3 kg/m2; calf volume: 497.52 ± 132.31 cm). Females had significantly larger β0 values than males, but males had significantly higher β2 values than females indicating higher calf venous compliance [males; ΔLimb Volume = 0.6665 ± 1.89051 + 0.0939 ± 0.1119 (Cuff Pressure) - 0.0212 ± 0.20587 (Cuff Pressure)2 vs. females; ΔLimb Volume = 1.8384 ± 5.28027 + 0.1083 ± 0.12568 (Cuff Pressure) - 0.0009 ± 0.00107). Compliance @ 20mmHg was significantly higher in males than females (0.28 ± 0.83mmHg vs. 0.06 ± 0.02 mmHg respectively). CONCLUSION: Consistent with previous research, this large data set found males to have higher calf venous compliance than females and females to have higher net capillary filtration than males.

The influence of race length on arterial compliance following an ultra-endurance marathon

There is inconclusive evidence concerning the effects of routine participation in ultra-endurance events on cardiovascular disease (CVD) risk. Arterial compliance is a reliable, non-invasive, and effective tool for evaluating CVD risk. The purpose of this research was to examine if race length influences acute changes in arterial compliance following an ultra-marathon event. A total of 46 ultra-marathon runners were recruited including 21 participants (39.8 ± 8.3 years, 6 females) in the 80-km event and 25 participants (43.7 ± 9.8 years, 3 female) in the 195-km event. Arterial compliance was measured via radial applanation tonometry (CR-2000, HDI) for diastolic pulse contour analysis before and following the race. Significant between-group differences were found for changes in large arterial compliance with a decrease (increase in stiffness) following the 195-km event and an increase following the 80-kilometre event (p < .05). Longer race lengths are associated with greater reductions in large arterial compliance following recreational ultra-marathon running. Assessment of arterial compliance might be a useful prognostic tool to assess the long-term risk of CVD among ultra-marathon runners.

Acute Effect of High-Intensity Eccentric Exercise on Vascular Endothelial Function in Young Men.

Choi, Y, Akazawa, N, Zempo-Miyaki, A, Ra, S-G, Shiraki, H, Ajisaka, R, and Maeda, S. Acute effect of high-intensity eccentric exercise on vascular endothelial function in young men. J Strength Cond Res 30(8): 2279-2285, 2016-Increased central arterial stiffness is as an independent risk factor for cardiovascular disease. Evidence regarding the effects of high-intensity resistance exercise on vascular endothelial function and central arterial stiffness is conflicting. The purpose of this study was to examine the effects of acute high-intensity eccentric exercise on vascular endothelial function and central arterial stiffness. We evaluated the acute changes in endothelium-dependent flow-mediated dilation (FMD), low-flow-mediated constriction (L-FMC), and arterial stiffness after high-intensity eccentric exercise. Seven healthy, sedentary men (age, 24 ± 1 year) performed maximal eccentric elbow flexor exercise using their nondominant arm. Before and 45 minutes after eccentric exercise, carotid arterial compliance and brachial artery FMD and L-FMC in the nonexercised arm were measured. Carotid arterial compliance was significantly decreased, and β-stiffness index significantly increased after eccentric exercise. Brachial FMD was significantly reduced after eccentric exercise, whereas there was no significant difference in brachial L-FMC before and after eccentric exercise. A positive correlation was detected between change in arterial compliance and change in FMD (r = 0.779; p ≤ 0.05), and a negative correlation was detected between change in β-stiffness index and change in FMD (r = -0.891; p < 0.01) with eccentric exercise. In this study, acute high-intensity eccentric exercise increased central arterial stiffness; this increase was accompanied by a decrease in endothelial function caused by reduced endothelium-dependent vasodilation but not by a change in endothelium-dependent vasoconstriction.

Impact of chronic changes in arterial compliance and resistance on left ventricular ageing in humans.

Left ventricular systolic elastance (Ees) and diastolic elastance (Eed) correlate with arterial elastance (Ea), but it is unknown how chronic changes in arterial compliance and resistance, which determine Ea, might differentially affect cardiac properties with ageing. We sought to characterize chronic changes in pulsatile and resistive arterial load and correlate them with longitudinal changes in LV structure and function in a prospective, community-based study. Comprehensive echocardiography was performed in 722 subjects participating in a randomly selected community-based study at two examinations separated by 4 years, allowing for assessment of LV Ees, Eed, and end-diastolic volume (EDV), Ea, total arterial compliance, and systemic vascular resistance at both examinations. Chronic changes in resistance and heart rate were the dominant contributors to change in Ea. Changes in arterial compliance had little impact on changes in Ea, but were strongly associated with changes in Ees. The combination of increased resistance and decreased compliance was associated with the largest increase in LV diastolic stiffness, an effect that was mediated by a decrease in LVEDV. In contrast, subjects with both improved arterial compliance and decreased resistance displayed an increase in LVEDV over time, with no increase in LV Eed. Increases in pulsatile arterial load with ageing contribute more to LV systolic stiffening, while combined pulsatile and resistive loading changes are associated with positive and negative chamber remodelling and diastolic stiffness. Therapies designed to improve arterial resistance and particularly to enhance aortic compliance may hold promise to prevent or reverse cardiac ageing and its sequelae.