Pressure Pulse Wave Research Articles

Quantitative stress assessment by blood pressure pulse wave obtained in tele-operating a mobile robot with delay

Quantitative stress assessment by blood pressure pulse wave obtained in tele-operating a mobile robot with delay

Central hemodynamics are associated with fetal outcomes in pregnancies of advanced maternal age.

Age is a known risk factor for both maternal cardiovascular disease and adverse outcomes in pregnancy. We aimed to characterize the hemodynamic profiles in pregnancies of advanced maternal age (AMA) and correlate these with fetal outcomes. This was a prospective observational study of pregnancies undergoing antenatal testing. Maternal hemodynamics were measured non-invasively using an imaging probe at the descending aorta and the Uscom BP+arm cuff utilizing pulse pressure wave analysis. The Wilcoxon rank-sum test, Fisher's exact test, and Spearman rank correlation test were used for statistical analysis in R. Hemodynamic measurements, neonatal birthweight. Twenty-one AMA and twenty-four control patients were enrolled. Mean age±SD was 39±3.22 in the AMA cohort and 28±4.32 in the control cohort (p<0.001). AMA patients were evaluated at a later gestational age (36 4/7 weeks) compared to control (34 1/7 weeks, p=0.02). Between groups, there was no difference in BMI, race, hypertensive disease, diabetes, asthma, drug use, or indication for antenatal testing. 38% (AMA) and 37% (control) had hypertensive disorders of pregnancy. In AMA patients but not control patients, cardiac output (r=0.52, p=0.01), systemic vascular resistance (r=-0.53, p=0.01), and systemic vascular resistance index (r=-0.62, p=0.002) were significantly correlated with neonatal birthweight percentile. Hemodynamic alterations consistent with a low output, high resistance cardiovascular circuit were associated with lower birthweight in AMA, but not in control pregnancies.

Modeling blood flow in viscoelastic vessels: the 1D augmented fluid–structure interaction system

Nowadays mathematical models and numerical simulations are widely used in the field of hemodynamics, representing a valuable resource to better understand physiological and pathological processes in different medical sectors. The theory behind blood flow modeling is closely related to the study of incompressible flow through compliant thin-walled tubes, starting from the incompressible Navier–Stokes equations. Furthermore, the mechanical interaction between blood flow and vessels wall must be properly described by the model. Recent works showed the benefits of characterizing the rheology of the vessel wall through a viscoelastic law. Taking into account the viscous contribution of the wall material and not simply the elastic one leads to a more realistic representation of the vessel behavior, which manifests not only an instantaneous elastic strain but also a viscous damping effect on pulse pressure waves, coupled to energy losses. In this context, the aim of this work is to propose an easily extensible one-dimensional mathematical model able to accurately capture fluid–structure interactions. The originality of the model lies in the introduction of a viscoelastic tube law in PDE form, valid for both arterial and venous networks, leading to an augmented fluid–structure interaction system. In contrast to well established mathematical models, the proposed one is natively hyperbolic. The model is solved with an efficient and robust second-order numerical scheme; the time integration is based on an Implicit–Explicit Runge–Kutta scheme conceived for applications to hyperbolic systems with stiff relaxation terms. The validation of the proposed model is performed on several different test cases. Results obtained in Riemann problems, adopting a simple elastic tube law for the characterization of the vessel wall, are compared with available exact solutions. To validate the contribution given by the viscoelastic term, the Method of Manufactured Solutions has been applied. Specific tests have been designed to verify the well-balancing with respect to fluid-at-rest condition and the accuracy-preserving property of the scheme. Finally, a specific test case with an inlet pulse pressure wave has been designed to assess the effects of viscoelasticity with respect to a simple elastic behavior of the vessel wall. The complete code, written in MATLAB (MathWorks Inc.) language, with the implemented test cases, is made available in Mendeley Data repository.

Arterial elastic properties and central aortic pressure in patients with ankylosing spondylitis

In recent years, arterial stiffness has been shown to be increased in ankylosing spondylitis (AS). However, this issue has not been sufficiently studied today. Objective: to investigate central aortic pressure values and pulse wave velocity (PWV) in patients with AS and their relationship to the clinical manifestations of the disease. Subjects and methods . A total of 47 patients (mean age 37.0+10.1) with AS were examined. ASDAS-CRP averaged 3.2+0.9; the duration of AS was 6.0+4.6 years; and the radiographic stage of sacroiliitis was 2.3+1.4. A control group included 33 healthy individuals. The groups were matched for age, gender, and office blood pressure (BP). Central aortic pressure and PWV were determined by applanation tonometry on a SphygmoCor apparatus (AtCorMedical, Australia). The Mann-Whitney U test and the Spearman correlation coefficient test were used for statistical analysis. Results and discussion . In the patients with AS, central systolic and diastolic BP was significantly higher than that in the controls (115.4+14.04 and 101.1 + 10.2 mm Hg, p=0.00001 and 78.6+12.3 and 71.8+7.3 mm Hg respectively, p=0.001). The patients with AS showed a 15.01% increase in mean central aortic pressure values compared to the control group (106.5+13.7 and 92.6+9.4 mm Hg, respectively; p=0.0001). Carotid-femoral PWV averaged 6.6+1.7 m/sec in the patients with AS and 5.20+0.96 m/sec in the controls (p=0.0001). There was a direct correlation of PWV with the occiput-wall distance r= 0.36; p=0.01) and an inverse correlation with Schober's test (r=-0.54; p=0.0001). Conclusion. The patients with AS were found to have increased arterial stiffness parameters, such as PWV, central aortic pressure, central diastolic BP, and central hemodynamic pressure. PWV was demonstrated to be related to clinical data.

Оценка скорости распространения пульсовой волны артериального давления на основе данных измерения пневматическим датчиком со встроенным каналом ЭКГ

Оценка скорости распространения пульсовой волны артериального давления на основе данных измерения пневматическим датчиком со встроенным каналом ЭКГ

Highlights of the December issue.

Highlights of the December issue.

Dissociation of Carotid and Forearm Pressure Decay Constants (tau), Windkessel Compliances, and Pulse Wave Velocities: Implications for Circulatory Models

Windkessel (WK) models have often been used to simulate the arterial circulation. We studied a critical characteristic of WK function, the arterial pressure-decay constant tau, to test whether all arterial regions share the same WK characteristics, which should theoretically be related to arterial stiffness. We performed carotid and forearm arterial tonometry (Sphygmocor) and modeled arterial pressure (P) as A + (SBP − A)·exp[−(t − t0)/tau], where A = minimum pressure, SBP = systolic BP, t = time, t0 = start of decay). Model validity was supported by strong between-site correlations for t0 and A. We also measured central and peripheral Pulse Wave Velocity (PWV, Colin VP1000) and calculated arterial compliances (1/PWV2) in the heart-femoral (hf) and femoral-ankle (fa) regions. For the full cohort [n = 98, mean (SD): age 50 (20) years, weight 81 (17) kg, BP 135/77 (17/12) mmHg, 38% female], carotid and forearm taus were different [283 (126) vs. 199 (88) ms, p < 0.000] and uncorrelated (r2 = 0.01). Although hf and fa arterial compliances were well correlated (p < 0.000), neither was closely correlated with carotid or forearm tau (r2 < 0.06). In a subset (n = 22), carotid and brachial blood flow (Ultramark 9) were measured and regional WK compliances were calculated (= tau/regional resistance). Carotid blood flow [571 (216) vs. 117 (84) mL/min, p < 0.000] and WK compliance [0.031 (0.017) vs. 0.004 (0.004) mL/mmHg, p < 0.000] were much higher than corresponding forearm values. We conclude that: (1) tau and WK compliance are regional, not systemic indicators, (2) neither carotid nor forearm tau reflects large artery stiffness, and (3) a single WK model cannot adequately describe the arterial circulation.

The relationship of blood pressure with uric acid and bilirubin in young lean and overweight/obese men and women: the African-PREDICT study.

Mounting evidence supports the central role of oxidative stress and inflammation in obesity and the development of hypertension. However, most studies focusing on the non-enzymatic antioxidants, such as uric acid and bilirubin, and their relationship with obesity and hypertension were done in older populations with overt cardiovascular disease. The aim of this study was therefore to compare measures of cardiovascular function (blood pressure and arterial stiffness) and non-enzymatic antioxidants (uric acid and bilirubin) between young healthy lean and overweight/obese men and women and to investigate the link between these variables. We grouped 967 men and women (aged 20-30 years) according to body mass index (BMI) categories (lean BMI < 25 kg/m2; overweight/obese BMI ≥ 25 kg/m2). Cardiovascular measurements included 24 h blood pressure and carotid-femoral pulse wave velocity. Serum samples were used to analyse uric acid and bilirubin. Women and men with a BMI ≥ 25 kg/m2 displayed higher 24 h blood pressure (P < 0.001) and uric acid (P ≤ 0.014) than their lean counterparts; lean women showed higher bilirubin (P < 0.001). In multi-variable adjusted regression analyses we found that 24 h systolic blood pressure was independently associated with uric acid (R2 = 0.10; β = 0.19; P = 0.017) only in overweight/obese women. In lean women a negative association of 24 h systolic blood pressure with bilirubin (R2 = 0.03; β = -0.14; P = 0.018) was found. No associations were found in men. In conclusion, we found adverse associations between blood pressure and uric acid in young healthy women with increased adiposity, but not in lean women or men.

A machine learning method correlating pulse pressure wave data with pregnancy.

Pulse feeling , representing the tactile arterial palpation of the heartbeat, has been widely used in traditional Chinese medicine (TCM) to diagnose various diseases. The quantitative relationship between the pulse wave and health conditions however has not been investigated in modern medicine. In this paper, we explored the correlation between pulse pressure wave (PPW), rather than the pulse key features in TCM, and pregnancy by using deep learning technology. This computational approach shows that the accuracy of pregnancy detection by the PPW is 84% with an area under the curve (AUC) of 91%. Our study is a proof of concept of pulse diagnosis and will also motivate further sophisticated investigations on pulse waves.

Peculiarities of Cardiohemodynamics and its Autonomic Regulation in Elderly People

The study was aimed to the experimental verification of the authors’ hypothesis that in elderly people an endogenous functional mechanism develops during late ontogeny to protect muscle effectors of the cardiovascular system (CVS) against negative effects of excessive activity of the sympathetic nervous system by partial replacement of its neurotransmitter norepinephrine with humoral catecholamines. Experiments were carried out using our original method of arterial piezopulsometry which allows evaluation of cardiohemodynamic parameters, as well as the spectral power of oscillations of VmaxPP and TNN parameters of arterial blood pressure pulse waves caused by regulatory effects of the autonomic nervous and endocrine systems. Such a replacement is assumed to be crucial for raising the metabolic tolerance of the CVS in elderly people to an age-related increase in oxygen deficiency, as well as for reducing the incidence of tachyarrhythmia, stenocardia and other cardiac pathological conditions under the influence of psychoemotional and physical stressors.

P4568Effect of intravitreal anti-vascular endothelial growth factor therapy on aortic stiffness and serum interleukin-6 levels in hypertensive patients with age-related macular degeneration

Abstract Purpose Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in adults over 65 years old and it is associated with moderate to severe arterial hypertension and increased aortic stiffness. Anti-vascular endothelial growth factor (anti-VEGF) agents, injected intravitreally, can reverse the symptoms of neovascular (wet) AMD. We sought to investigate whether intravitreal anti-VEGF therapy may influence aortic elastic properties of hypertensive patients with AMD. Methods 54 hypertensive patients with exudative (“wet”) AMD received intravitreal ranibizumab (0.5mg) and blood pressure (BP) and carotid-femoral pulse wave velocity (PWV) were measured at baseline (approximately 2 days before the first injection), 24 h after the first and second injection (time interval between the injections: 1 month) and 1 month after the second injection. Serum levels of high sensitivity interleukin-6 (hsIL-6) were measured at three time points (baseline, first injection, 1 month after the second injection). Results Systolic BP decreased by 3.2 mmHg and by 3.0 mmHg after the first and second injection respectively and remained decreased (by 2.6 mmHg) 1 month after the second injection (overall p=0.07, by ANOVA). The changes in diastolic BP were minimal (overall p=0.74). Ranibizumab injection caused a significant decrease of PWV after the first (by 0.34 m/s) and the second injection (by 0.31 m/s). Furthermore, as upper figure shows, PWV remained decreased 1 month after the second injection. Among the treated naïve eyes, 45 (83%) had a good response to ranibizumab while 9 (17%) were poor responders. Interestingly, PWV decreased significantly in good responders to AMD therapy (overall p=0.004) whereas, it increased in poor responders (overall p=0.21) over the study period. In responders to therapy serum hsIL-6 decreased after the first injection and remained decreased 1 month after the second injection (by 0.63 pg/ml, overall p=0.02, lower figure). The levels of hsIL-6 increased in poor responders (overall p=0.54). Ranibizumab, PWV and serum hsIL-6 levels Conclusions This is the first study showing that intravitreal administration of ranibizumab, a anti-VEGF used for improvement of wet AMD was associated with a beneficial acute and mid-term systematic effect on aortic elastic properties. Changes in systemic inflammatory activation may be involved. The findings have important implications for assessing the effect of anti-VEGF interventions on cardiovascular performance in hypertensive patients with exudative AMD.

P1584The prognostic significance of the blood pressure-pulse wave velocity association for cardiovascular outcomes and mortality in hemodialysis patients

Abstract Introduction and purpose Hemodialysis patients have premature arterial stiffness, and the relationship between pulse wave velocity (PWV) and blood pressure (BP) may be different than in other hypertensives. Previous studies showed that when BP decrease is accompanied by PWV decrease the survival is improved. The aim of this study is to examine the prognostic significance of BP sensitivity of PWV for major cardiovascular outcomes and all-cause mortality in hemodialysis patients. Methods This is a prospective cohort study including 242 hemodialysis patients [age, 62.6±14.2 years; female, 91 (37.6%); hemodialysis vintage, 41.53±43.46]. All subjects underwent 48-hour-ABPM with Mobil-O-Graph-NG and followed-up for 33.17±19.68 months. The within-individual MBP-PWV association (MBP, dependent and PWV independent variable) was evaluated using the beta-coefficient value from simple linear regression analysis for each patient. The primary end-point was first occurrence of all-cause death, non-fatal myocardial infarction or non-fatal stroke. Secondary end-points were: (i) all-cause mortality; (ii) cardiovascular mortality; (iii) a combination of cardiovascular events. Results Patients who experienced the primary end-point during follow-up had significantly lower beta-coefficient levels (primary end-point: 19.877±3.975 vs 18.483±3.550, p=0.008). Higher quartiles of beta-coefficients (indicating dependency of PWV on MBP) were associated with higher cumulative freedom from the primary end-point (50.8%, 60.0%, 70.0% and 80.3% for quartiles 1 to 4 respectively; logrank-p=0.001), higher overall survival (60.7%, 61.7%, 73.3%, 86.9%; logrank-p=0.002) and higher cardiovascular survival (78.7%, 75.0%, 81.7%, 91.8% for quartiles 1 to 4; logrank-p=0.044). The future risk for the primary end-point, all-cause and cardiovascular mortality and the combined outcome was progressively increasing for lower quartiles of beta-coefficients (HR for all-cause mortality 3.395; 95% CI: 1.524–7.563, p=0.003 for quartile 1 vs quartile 4). Age (OR: 1.046, 95% CI: 1.016–1.077 per year increase, p=0.003) and 48h heart rate (OR: 0.949, 95% CI: 0.916–0.982 per bpm increase, p=0.003) were independently associated with weaker relationship between 48h-MBP and 48h-PWV. Conclusions Lower within-individual MBP-PWV association, based on AMBP recordings, is associated with higher risk of death and cardiovascular events in hemodialysis. These findings support that BP-independent arterial stiffness may be the underlying factor for adverse outcomes in these individuals.

Machine learning in cardiovascular flows modeling: Predicting arterial blood pressure from non-invasive 4D flow MRI data using physics-informed neural networks

Advances in computational science offer a principled pipeline for predictive modeling of cardiovascular flows and aspire to provide a valuable tool for monitoring, diagnostics and surgical planning. Such models can be nowadays deployed on large patient-specific topologies of systemic arterial networks and return detailed predictions on flow patterns, wall shear stresses, and pulse wave propagation. However, their success heavily relies on tedious pre-processing and calibration procedures that typically induce a significant computational cost, thus hampering their clinical applicability. In this work we put forth a machine learning framework that enables the seamless synthesis of non-invasive in-vivo measurement techniques and computational flow dynamics models derived from first physical principles. We illustrate this new paradigm by showing how one-dimensional models of pulsatile flow can be used to constrain the output of deep neural networks such that their predictions satisfy the conservation of mass and momentum principles. Once trained on noisy and scattered clinical data of flow and wall displacement, these networks can return physically consistent predictions for velocity, pressure and wall displacement pulse wave propagation, all without the need to employ conventional simulators. A simple post-processing of these outputs can also provide a relatively cheap and effective way for estimating Windkessel model parameters that are required for the calibration of traditional computational models. The effectiveness of the proposed techniques is demonstrated through a series of prototype benchmarks, as well as a realistic clinical case involving in-vivo measurements near the aorta/carotid bifurcation of a healthy human subject.

Modeling arterial pulse waves in healthy aging: a database for in silico evaluation of hemodynamics and pulse wave indexes.

The arterial pulse wave (PW) is a rich source of information on cardiovascular (CV) health. It is widely measured by both consumer and clinical devices. However, the physical determinants of the PW are not yet fully understood, and the development of PW analysis algorithms is limited by a lack of PW data sets containing reference CV measurements. Our aim was to create a database of PWs simulated by a computer to span a range of CV conditions, representative of a sample of healthy adults. The typical CV properties of 25–75 yr olds were identified through a literature review. These were used as inputs to a computational model to simulate PWs for subjects of each age decade. Pressure, flow velocity, luminal area, and photoplethysmographic PWs were simulated at common measurement sites, and PW indexes were extracted. The database, containing PWs from 4,374 virtual subjects, was verified by comparing the simulated PWs and derived indexes with corresponding in vivo data. Good agreement was observed, with well-reproduced age-related changes in hemodynamic parameters and PW morphology. The utility of the database was demonstrated through case studies providing novel hemodynamic insights, in silico assessment of PW algorithms, and pilot data to inform the design of clinical PW algorithm assessments. In conclusion, the publicly available PW database is a valuable resource for understanding CV determinants of PWs and for the development and preclinical assessment of PW analysis algorithms. It is particularly useful because the exact CV properties that generated each PW are known.NEW & NOTEWORTHY First, a comprehensive literature review of changes in cardiovascular properties with age was performed. Second, an approach for simulating pulse waves (PWs) at different ages was designed and verified against in vivo data. Third, a PW database was created, and its utility was illustrated through three case studies investigating the determinants of PW indexes. Fourth, the database and tools for creating the database, analyzing PWs, and replicating the case studies are freely available.

Pressure pulse wave attenuation model coupling waveform distortion and viscous dissipation for blockage detection in pipeline

AbstractSafety issues are always a major concern in the oil and gas transportation facilities. Equipment damages are frequently encountered due to solid deposition such as gas hydrate deposition. A fast and efficient detection of the location, length, and rate of the accumulating blockage will significantly help relieve the potential risk. Most existing pressure wave‐based models suffer the difficulty to properly predict the blockage percentage arising from the ignorance of the wave attenuation. In the present work, an attenuation model to describe the transportation of the pressure pulse wave in gas is developed; the effects of waveform distortion and absorption as a result of the nonlinear effect and viscous dissipation are collectively considered for the first time. A simplified procedure to couple the wave attenuation in the model is proposed. The results show that the model can remarkably improve the prediction accuracy of blockage percentage by reducing the errors from −9.0% to −4.2%. Moreover, the attenuation process of the pressure pulse wave is determined to consist of three stages. The effect of waveform distortion on amplitude mainly occurs in the second stage, when our proposed model shows an improved prediction. The performance of the proposed model will help the early warning of the blockage in the pipelines and effectively avoid the potential injury and financial loss.

Impact of Vascular Function on Maximum Power Output in Elite Handball Athletes

ABSTRACTPurpose: To evaluate vascular function and its relationship to cardiorespiratory fitness in professional handball athletes. Method: We examined 30 male professional handball athletes (age 27 ± 4 y) and 10 male sedentary controls (age 26 ± 5 y) at rest. The workup included exercise testing via ergometry. To assess vascular function, a validated electronic model of the arterial tree (vasc assist 2®) was used. It replicates noninvasively acquired pulse pressure waves by modulating the relevant functional parameters of compliance, resistance, inertia, pressure, and flow. The maximum oxygen uptake (VO2max) was estimated using the validated heart rate ratio method. Results: Athletes had a significantly lower systolic and diastolic central blood pressure (cBP) compared to controls (102 ± 9/60 ± 9 vs. 110 ± 8/74 ± 9 mmHg, p < .01), whereas aortic pulse wave velocity (PWV) (6.2 ± 0.8 vs. 6.3 ± 0.5 m/s, p = .45) and augmentation index at a heart rate of 75 (Aix@75) (−4 ± 12 vs. −13 ± 16%, p = .06) were not different. Resistance index (R) (15.9 ± 4.4 vs. 10.6 ± 0.6, p = .001) and maximum power output (MPO) (3.55 ± 0.54 vs. 2.46 ± 0.55 Watt/kg, p < .001) were significantly higher in athletes compared to controls. We found no relevant correlation between MPO, resting heart rate, PWV, Aix@75, and cBP. A higher VO2max (p = .02) and a lower R (p < .01) were significant predictors of a higher MPO in athletes. Conclusion: R had an independent and strong correlation to MPO in athletes, which might help to disentangle the contribution of aerobic capacity and arterial function to physical power.

Biomarkers of cardiovascular risk across phenotypes of osteoarthritis

BackgroundThe objective of this study was to explore the associations between ultrasonographic and radiographic joint scores and levels of arterial CVD risk markers in patients with osteoarthritis (OA). Secondly, to compare the levels of arterial CVD risk markers between OA phenotypes and controls.MethodThe “Musculoskeletal pain in Ullensaker” Study (MUST) invited residents of Ullensaker municipality with self-reported OA to a medical examination. OA was defined according to the American College of Rheumatology (ACR) criteria and phenotyped based on joint distribution. Joints of the hands, hips and knees were examined by ultrasonography and conventional radiography, and scored for osteosteophytes. Hands were also scored for inflammation by grey scale (GS) synovitis and power Doppler (PD) signal. Control populations were a cohort of inhabitants of Oslo (OCP), and for external validation, a UK community-based register (UKPC).Pulse pressure augmentation index (AIx) and pulse wave velocity (PWV) were measured using the Sphygmocor apparatus (Atcor®). Ankel-brachial index (ABI) was estimated in a subset of patients. In separate adjusted regression models we explored the associations between ultrasonography and radiograph joint scores and AIx, PWV and ABI. CVD risk markers were also compared between phenotypes of OA and controls in adjusted analyses.ResultsThree hundred and sixty six persons with OA were included (mean age (range); 63.0 (42.0–75.0)), (females (%); 264 (72)). Of these, 155 (42.3%) had isolated hand OA, 111 (30.3%) had isolated lower limb OA and 100 (27.3%) had generalized OA. 108 persons were included in the OCP and 963 persons in the UKPC; (mean age (range); OCP: 57.2 (40.4–70.4), UKPC: 63.9 (40.0–75.0), females (%); OCP: 47 (43.5), UKPC: 543 (56.4%). Hand osteophytes were associated with AIx while GS and PD scores were not related to CVD risk markers. All OA phenotypes had higher levels of AIx compared to OCP in adjusted analyses. External validation against UKPC confirmed these findings.ConclusionsHand osteophytes might be related to higher risk of CVD. People with OA had higher augmented central pressure compared to controls.Words 330.

Area of the pressure-strain loop during ejection as non-invasive index of left ventricular performance: a population study

BackgroundPrevious studies highlighted the usefulness of integrating left ventricular (LV) deformation (strain) and hemodynamic parameters to quantify LV performance. In a population sample, we investigated the anthropometric and clinical determinants of a novel non-invasive index of LV systolic performance derived from simultaneous registration of LV strain and brachial pressure waveforms.MethodsThree hundred fifty-six randomly recruited subjects (44.7% women; mean age, 53.9 years; 47.5% hypertensive) underwent echocardiographic and arterial data acquisition. We constructed pressure-strain loops from simultaneously recorded two-dimensional LV strain curves and brachial pressure waveforms obtained by finger applanation tonometry. We defined the area of this pressure-strain loop during ejection as LV ejection work density (EWD). We reported effect sizes as EWD changes associated with a 1-SD increase in covariables.ResultsIn multivariable-adjusted analyses, higher EWD was associated with age, female sex and presence of hypertension (P ≤ 0.0084). In both men and women, EWD increased independently with augmentation pressure (effect size: + 59.1 Pa), central pulse pressure (+ 65.7 Pa) and pulse wave velocity (+ 44.8 Pa; P ≤ 0.0006). In men, EWD decreased with relative wall thickness (− 29.9 Pa) and increased with LV ejection fraction (+ 23.9 Pa; P ≤ 0.040). In women, EWD increased with left atrial (+ 76.2 Pa) and LV end-diastolic (+ 43.8 Pa) volume indexes and with E/e’ ratio (+ 51.1 Pa; P ≤ 0.026).ConclusionOlder age, female sex and hypertension were associated with higher EWD. Integration of the LV pressure-strain loop during ejection might be a useful tool to non-invasively evaluate sex-specific and interdependent effects of preload and afterload on LV myocardial performance.

Abstract 446: The Impact of the Menstrual Cycle on the Cardiovascular System

The stage of the menstrual cycle is an exquisite regulation of female hormone and cardiovascular adaptation to prepare for pregnancy. However, there are still many unclear areas in the study of the influence of the menstrual cycle on cardiovascular function. Since the arterial pulse wave provides insightful information about the cardiovascular system, this study aimed to study cardiovascular adaptation in three phases of the menstrual cycle through non-invasive blood pressure and radial pulse wave measurements. In this observational study, we recruited 113 healthy women with regular menstrual cycles(25±35 days). All participants underwent blood pressure and radial pulse measurements in three stages of the menstrual cycle, including menses period, proliferative phase, and secretory phase. The Fourier series method was used to calculate the first ten harmonic amplitudes of the radial pulse wave(C1~C10). The results showed no significant systolic and diastolic changes in the three phases of menstruation. However, compared to the other two phases, women in menses period had lower C2 and higher C4, C6 and C7. (Figure 1) C4 and C7 are two indices that are inversely related to arterial stiffness and peripheral arterial impedance. Thus, during the menstrual cycle, female hormones may be involved in the regulation of vascular elasticity and peripheral vasodilatation, which in turn changed the radial pulse spectrum. In summary, the menstrual cycle has an impact on the radial pulse spectrum and could alter arterial stiffness to accommodate the physiological needs of the pre-pregnancy period.

Abstract 176: The Effects of Age, Menopause, and Body Mass Index on Blood Pressure and Radial Pulse Wave in Women

Age, gender, and body mass index (BMI) play an important roles in cardiovascular risk. However, the independent effects of menopause on the ventricular-arterial system in female individuals have not been fully investigated. Thus, this study aimed to assess the effect of age, menopause and body mass index on different hemodynamic parameters including systolic blood pressure (SBP), diastolic blood pressure (DBP) and harmonics of radial pulse wave. This study enrolled 327 female subjects(230 pre-menopausal and 97 post-menopausal), aged 20-87 and without cardiovascular history. SBP and DBP were evaluated by an automatic blood pressure monitor. A 12-second continuous radial pulse data was recorded using medical grade pulse measuring instrument and standard protocol. Spectrum analysis of radial pressure wave was calculated and transformed into first five harmonic amplitudes(C1~C5). We further performed multivariable linear regression models to assess the independent effects of age, menopause, and body mass index on SBP, DBP, and C1 to C5 respectively. The mean age, BMI, SBP, and DBP in enrolled subjects were 43±13 yeas, 23±4 kg/m 2 , 116±16 mmHg, and 69±11 mmHg. Regression analysis demonstrated that age was positively correlated with SBP(P&lt;0.001), whereas effect of age exerted no significant influence on DBP. BMI had positive associations with SBP and DBP(P&lt;0.001), while menopause had no significant effect on neither SBP nor DBP. Multivariable linear regression showed that menopause had significant effects on C1 (P&lt;0.05) and C3 (P&lt;0.05). C1 is associated with atherosclerosis and is an independent risk predictor for adverse cardiac events. We proposed that an increase in cardiovascular risk during menopause may be due to hormonal changes exacerbating the progression of atherosclerosis and reflected in the radial pulse spectrum. Conclusively, this study demonstrates that age and BMI have an independent effect on SBP, whereas menopause has no significant independent effect on SBP. The effects of menopause on C1 and C3, independent of age and BMI, may partially explain the reasons of dramatically increased cardiovascular risk during menopause and provide clues to the underlying mechanisms of the change in cardiovascular system.