Arterial Wave Research Articles

Abstract WP485: Racial Differences in the Association Between Central Hemodynamic Parameters and Neuropsychological Assessments

Introduction: Despite a significantly younger at time of stroke, African Americans are at increased risk for post-stroke cognitive impairment compared to whites. Although central arterial stiffness is a well-established correlate of cognitive function in whites, its predictive value in African Americans is not well characterized. We hypothesized that arterial stiffness measures previously associated with declines in cognition may be more robust in African Americans compared to whites. Methods: We administered the Mini Mental State Examination (MMSE), Trail Making Test Part-A (TMTA) and Part-B (TMTB), and Symbol Digit Modalities Test (SDMT) to 54 stroke-free adults (28 African Americans and 26 whites). Central hemodynamic parameters including carotid-femoral pulse wave velocity (PWV), central systolic blood pressure (cSBP), central pulse pressure (cPP), and heart rate-corrected augmentation index (AIx@75) were recorded for each study participant. Univariate analysis was used to evaluate age, sex and mean arterial pressure (MAP) mean-adjusted differences in central hemodynamics. We also evaluated associations between central hemodynamics and neuropsychological test by race. Results: Mean-adjusted PWV values were significantly higher in African Americans compared to whites with values ranging from 8.8 m/s to 7.8 m/s, respectively. Adjusted mean cSBP and AIx@75 were also significantly increased in African Americans. Among whites, unadjusted PWV values were negatively associated with TMTA and TMTB z-scores. Unadjusted AIx@75 was negatively associated with TMTB z-scores in African Americans but not whites. African Americans with MMSE and SDMT z-scores <0 had higher PWV values compared to whites ((9.4 m/s vs 7.9 m/s) and (9.7 m/s vs 7.7 m/s), respectively) and those with TMTB z-scores <0 had higher cSBP values (123.1 mmHg vs 114.4 mmHg). Conclusion: African Americans had higher arterial stiffness compared to whites. Neuropsychological test were associated with arterial stiffness in white study participants but only arterial wave reflections in African Americans. Longitudinal follow-up is warranted to assess specific central hemodynamic parameters associated with cognitive impairments and dementia in African Americans.

Evaluation of arterial stiffness in cardiac surgical patients using applanation tonometry.

Context:Applanation tonometry enables the noninvasive analysis of arterial pressure wave morphology. Applanation tonometry provides the augmentation index (AIx, %), an index of arterial stiffness that partially reflects arterial-ventricular (A-V) coupling. In addition, applanation tonometry provides the dP/dt (rate of intraventricular pressure variation over time), which reflects myocardial contractility, and the sub-endocardial viability ratio (SEVR, %), which is an indicator of myocardial oxygen supply and demand. There are no data on how cardiac surgery can modify these tonometry-derived indexes.Aim:The aim was to assess changes in AIx, dP/dt, and SEVR in patients undergoing cardiac surgery.Subjects and Methods:This observational study was conducted at the University Hospital of Siena. We studied 32 patients before cardiac surgery in intensive care unit (ICU) on admission and at ICU discharge. We measured AIx, dP/dt, and SEVR using applanation tonometry (SphygmoCor). Changes in variables over time were evaluated by analysis of variance for repeated measurements.Results:AIx decreased significantly from T1 [28.8%, interquartile range (IQR) 21.6–36.6%] to T2 (16.2% IQR 8.1–22.4%) and T3 (14.5% IQR 7.9–23.6%) (P = 0.01). dP/dt increased significantly from T1 (635 mmHg/ms, IQR 534–756 mmHg/ms) to T3 (751 mmHg/ms, IQR 651–1013 mmHg/ms; P = 0.03). The SEVR was lower at T2 than at T1, but returned toward T1 values by T3.Conclusions:Cardiac surgery was associated with an improvement in arterial stiffness, A-V coupling, and myocardial contractility as assessed using applanation tonometry. The results suggest, however, a transient imbalance between myocardial oxygen supply and demand in the immediate postoperative period.

Comparison of normal saline and heparinized solutions for the maintenance of arterial catheter pressure waves: a randomized pilot study

Objectives: Heparinized continuous-flush solutions are used to maintain arterial catheter patency. We sought to compare the patency and pressure wave integrity of radial artery catheters maintained with heparinized or nonheparinized infusions. Methods: Patients in the emergency room and intensive care unit were consecutively enrolled and randomly assigned to receive a heparinized solution (heparin group, n = 18) or normal saline (NS group, n = 16). The functional duration of radial artery catheters, the differences between arterial catheter and brachial cuff blood pressures, and the pressure wave curve quality were determined. Results: The mean duration of functional cannulas did not differ significantly between the heparin and NS groups (120 ± 129 and 105 ± 82 hours, respectively, P = 0.689). There was no difference in blood pressure between arterial catheter measurements and brachial cuff measurements between the two groups (P = 0.607). Kaplan-Meier analysis showed that the incidence of pressure wave dampening did not differ between the groups (log-rank test, P = 0.896). Conclusions: No significant differences were found between heparinized and nonheparinized flush solutions for maintaining radial artery catheter patency and function.

ASSOCIATION OF INDICATORS OF ARTERIAL RIGIDITY AND ARRITHMOGENESIS IN NOVOSIBIRSK MEN POPULATION

Pulse wave amplification and augmentation are considered as new indicators of arterial stiffness. It is of interest to study their association with electrocardiographic pro-arrhythmic patterns in the male population of Novosibirsk. Material and methods. We used data from a representative sample of 145 men aged 25-44 years from a population of inhabitants of Novosibirsk. Applanation tonometry of the radial artery and pulse wave analysis were performed using the SphygmoCor system (AtCorMedical, Australia). The Brugada pattern, the pattern of early ventricular repolarization and fragmentation of the QRS complex were determined on a resting electrocardiogram according to generally accepted current criteria. When analyzing the data, descriptive statistics methods and the general linear model (GLM) were used. Results. Fragmentation of the QRS complex in the in the area of the inferior wall of the left ventricle, regardless of age, body mass index and heart rate, was associated with a decrease in the ratio of amplification of pulse pressure ( F = 5.34; p = 0.022), amplification of pulse pressure ( F = 5.91; p = 0.016) and amplification of systolic pressure ( F = 5.02; p = 0.027). Conclusion. In the Novosibirsk male population, a decrease in pulse wave amplification was associated with fragmentation of the QRS complex. The results of this study demonstrate the relevance of an integrated assessment of prognostically significant indicators of arterial stiffness and ventricular pro-arrhythmia to study the possible cumulation of cardiovascular risk.

The Optimal Morphological Model for Arterial Blood Pressure Wave Related Classification: Comparison of Two Types of Kernel Function Mixtures

The morphological modeling methods are efficient in quantifying the change of arterial blood pressure (ABP) waves. The related works focus on minimizing the modeling error but ignore the classification related modeling expression in practical applications. In this study, we explored the optimal modeling method for ABP wave related classifications. Two types of conventional models, Gaussian or Lognormal kernel function mixtures, were employed to quantitively describe the change of ABP signals, and the parameters of different models were engaged to train the different classifiers by probabilistic neural network (PNN) and random forest (RF) for identifying the ABP waves by age, gender, and whether belonging to extreme bradycardia (EB) or extreme tachycardia (ET). Then, we defined some indexes about the performance of modeling and classifications as the references to compare the different models. The ABP signals of Fantasia and 2015 PhysioNet/CinC Challenge databases were exploited as the experimental data to select the optimal model. The modeling results show that the Lognormal kernel function mixtures have a lower error in ABP wave modeling. The two-sample Kolmogorov-Smirnov test (ks-test) results indicate that the parameters of all models are markedly different at a highly significant level (h = 1, p <; 0.05) between different groups. The classification results show that the classifiers based on the four-Gaussian function model have the best performance with the average Kappa coefficients (KC) of 99.160 ± 0.123%, while the average KC for the classifiers of two-Lognormal function models is 97.585 ± 0.172%, which means there is excessive information redundancy in the classifications by the three and four kernel functions models. Considering some other indexes such as time consumption and RAM space, the 2 Lognormal function model has more potential in practical applications.

Reconstruction of Continuous Brachial Arterial Pressure From Continuous Finger Arterial Pressure Using a Two-Level Optimization Strategy.

We attempt to reconstruct brachial arterial pressure (BAP) waves from finger arterial pressure waves measured using the vascular unloading technique without arm-cuff calibration. A novel method called two-level optimization (TOP) strategy is proposed as follows. We first derive a simplified transfer function (TF) based on a tube-load model with only two parameters to be estimated, a coefficient B and a time delay ∆t. Then, at level one, two minimization problems are formulated to estimate the optimal coefficient Bopt and time delay ∆topt. Then, we can derive an optimal TF hopt(t). However, this derivation requires true (or reference) BAP waves. Therefore, at level two, we apply multiple linear regression (MLR) to further model the relationship between the derived optimal parameters and subjects' physiologic parameters. Hence, eventually, one can estimate coefficient BMLR and time delay ∆tMLR from subject's physiologic parameters to derive the MLR-based TF hMLR(t) for the BAP reconstruction. Twenty-one volunteers were recruited for the data collection. The mean ± standard deviation of the root mean square errors between the reference BAP waves and the BAP waves reconstructed by hopt(t), hMLR(t), and a generalized transfer function (GTF) were 3.46 ± 1.42mmHg, 3.61 ± 2.28mmHg, and 6.80 ± 3.73mmHg (significantly larger with p < 0.01), respectively. The proposed method can be considered as a semi-individualized TF which reconstructs significantly better BAP waves than a GTF. The proposed TOP strategy can potentially be useful in more general reconstruction of proximal BP waves.

415 Comparison between two methods for assessing ventricular-arterial coupling: the Chen single-beat method and carotid artery wave intensity

Abstract Background Ventricular arterial coupling (VAC) can be defined as the ratio of the arterial elastance (Ea) to the ventricular elastance (Ees). . The Ea/Ees ratio has been consistently demonstrated to be a reliable and effective measure of cardiovascular performance. The Chen single-beat method is the most used non-invasive method for this measurement. Carotid artery wave intensity (WI) is also considered a index of VAC, as the first peak (W1) represents the forward compression wave, reflecting left ventricle (LV) contractile function. However, data about the relationship between the two methods are nowadays scarce. Purpose Aim of the study was to compare carotid WI and Ventricular-Arterial Coupling (VAC) in a population of patient with heart failure. Methods We examined 50 consecutive patients with heart failure (9 females, 41 males, mean age 67 + 12 years, range 29-97 years, 34 ischemic, 16 not ischemic). Carotid artery wave intensity was achieved merging the echo-tracking of the vessel with its doppler signal. Simultaneous not-invasive oscillometric blood pressure was obtained. The VAC was assessed by the ratio between the arterial elastance (Ea) and the end-systolic ventricular elastance (Ees). Ea was calculated from stroke volume (SV) and end-systolic pressure (Ea=(Systolic BP x 0.9)/SV) and Ees was calculated by the modified single-beat Chen method, using an estimated normalized ventricular elastance at arterial end-diastole (ENd) Ees = [Diastolic BP-(ENd(est) x Systolic BP x 0.9)]/(ENd(est) x SV). Three subgroups were created according to the left ventricle ejection fraction values (LVEF ≤ 35%, LVEF &amp;gt;35% &amp;lt;50%, LVEF ≥ 50%, with 26, 14, 10 patients respectively). Results The correlation between Ea/Ees and W1 was significant (Pearson’s correlation r= -0.35, p 0.01). The W1 and VAC values of the three LVEF-sorted subgroups were processed with ANOVA test (p 0.054 and p 0.0002 respectively). W1 values resulted to be, as expected, reduced especially in the group of severe ventricular dysfunction (mean 4,97+- 3,29), as well as the ventricular-arterial coupling was increased (mean 2.04 +- 1.04). Interestingly W1 shows to be correlated with the Left atrial volume index (Pearson’s correlation r= -0,30 p = 0,037). Conclusions Carotid WI technique seems to be a reliable method to estimate the ventricular-arterial interplay. Larger studies are needed to evaluate the respective role of W1 and Ea/Ees in the prognostic evaluation. Results EF ≤ 35 (n = 10) 35 &amp;lt; EF &amp;lt; 50 (n = 14) EF≥ 50 (n = 26) p value W1 4.97 ± 3.29 8.05 ± 3.79 7.85 ± 3.12 0.054 Ea/Ees 2.04 ± 1.04 1.39 ± 0.31 1.16 ± 0.3 0.0002 Abstract 415 Figure.

P1806 Relation between carotid artery wave intensity compression wave and left ventricular dp/dt

Abstract Background Invasive catheter-based studies demonstrated a correlation between left ventricular (LV) dP/dt, a well known index of contractility, and carotid artery wave intensity compression wave. It is possible to estimate LV dP/dt with ultrasound, evaluating the slope of continuous Doppler wave of mitral regurgitation in early systole. Wave intensity (WI) is achieved merging the echo-tracking of the common carotid artery with the simultaneous pulsed Doppler signal inside the vessel. The first peak (W1) represents the forward compression wave, reflecting theoretically LV contractile function. Nowadays data about the relationship between the two dP/dt methods are scarce. Purpose The aim of the study is to compare carotid artery WI and mitral regurgitation wave-derived LV dP/dt in a population of patients with ischemic and not ischemic heart failure. Methods We examined 31 consecutive patients with heart failure (7 females, 24 males, mean age 66.7 + 13.9 years, range 29-97 years, 21 ischemic, 10 not ischemic). All patients had at least a mild mitral regurgitation. Two subgroups were created according to the left ventricle ejection fraction values (LVEF ≤ 45% and LVEF &amp;gt; 45%, with 15 and 16 patients respectively). A simultaneous not-invasive brachial blood pressure was obtained. Results The W1 was significantly linearly correlated with the echocardiographic LV dP/dt value (r = 0.41, p 0.02). Both W1 and LV dP/dt correlated significantly with LV ejection fraction. Conclusions Carotid WI evaluation, and specifically its first peak W1, could be reinterpreted as an alternative method to estimate not invasively LV contractility performance. Larger studies are needed to evaluate the relative prognostic role of carotid artery W1 and LV dP/dt in clinical practice. Results LVEF ≤ 45 % (n = 15) LVEF &amp;gt; 45 % (n = 16) p value W1 6.19 +- 3.77 9.3 +- 3.43 0.02 dP/dT 789 +- 329 1244 +- 337 0.0007 Abstract P1806 Figure. Common Carotid Artery eTracking

P1528 Prognostic impact of pulmonary arterial wave reflection in heart failure

Abstract Background Pulmonary hypertension (PH) is prevalent and is associated with adverse outcomes in heart failure. The pathophysiology of PH is heterogeneous, including pre-capillary PH and combined pre- and post-capillary PH. The latter PH has been reported in experimental studies to cause wave reflection in pulmonary circulation, putting additional burden on right ventricle. This study tested the hypothesis that separating wave reflection would enhance risk stratification in heart failure. Methods This study included 152 patients with clinical stable heart failure associated with PH who were referred to echocardiography for hemodynamic assessment (age = 72 ± 13 years old, ejection fraction = 49 ± 21%). Pulmonary arterial wave reflection was characterised by separating PA pressure waveform into forward (Pf) and backward pressure (Pb) waves, based on the concept of wave intensity. PA pressure waveform was estimated from continuous Doppler tracing of tricuspid regurgitation. Flow velocity was measured by pulse Doppler at right ventricular outflow tract. Outcome data was obtained by reviewing medical charts. The endpoint was hospitalization for worsening heart failure (WHF). Results Figure A compares PA pressure waveforms (total and separated waves) obtained from 2 patients with and without WHF event. The patient with event had higher total pressure associated with late peak than the patient without event. Pb appeared later than Pf; it was markedly higher in the patient with event than the patient without event, although Pf was similar between both patients. Kaplan-Meier analysis demonstrated a significant separation of survival curves stratified by Pb (chi-square = 25.1, p &amp;lt; 0.001, figure B). During follow-up period of 1.5 ± 1.8 years, 65 patients (43%) experienced the endpoint. Sequential Cox analysis revealed that PASP remained significant after adjusted for left ventricular ejection fraction and E/e’ (hazard ratio = 1.017, p = 0.019). Pb also remained significant after the same adjustment (hazard ratio = 1.066, p = 0.003); the addition of Pb to a baseline model resulted in greater increase in predictive power than the addition of PASP (model chi-square: from 27.4 (baseline), to 37.6 (p = 0.004) for Pb, to 31.6 (p = 0.027) for PASP, figure C) Conclusions Pressure wave reflection in pulmonary artery is associated with early decompensation in heart failure. Abstract P1528 Figure.

P134 A New Method for Non-invasive Measurement of Arterial Wave Intensity, Speed and Reflection

P134 A New Method for Non-invasive Measurement of Arterial Wave Intensity, Speed and Reflection

Association Between Central Blood Pressure and Subclinical Cerebrovascular Disease in Older Adults.

Elevated blood pressure (BP) level is one of the most consistently identified risk factors for silent brain disease. BP values obtained at the proximal segment of the aorta (central BP) are more directly involved than brachial BP in the pathogenesis of cardiovascular disease. However, the association between central BP and silent cerebrovascular disease has not been clearly established. Participants in the CABL (Cardiovascular Abnormalities and Brain Lesions) study (n=993; mean age, 71.7±9.3 years; 37.9% men) underwent 2-dimensional echocardiography, arterial wave reflection analysis for determination of central BPs, and brain magnetic resonance imaging. Central BPs were calculated from the radial pulse waveform. Subclinical silent cerebrovascular disease was defined as silent brain infarction and white matter hyperintensity volume. Both brachial (P=0.014) and central pulse pressure (P=0.026) were independently associated with silent brain infarctions after adjustment for clinical variables, but not adjusting for each other. None of the brachial BP values was associated with upper quartile of white matter hyperintensity volume in multivariable analysis. Both central systolic BP (P<0.001) and central pulse pressure (P<0.001) were significantly associated with upper quartile of white matter hyperintensity volume in multivariable analysis, even after adjustment for brachial BP. In a predominantly older population-based cohort, both brachial and central pulse pressure were independently associated with silent brain infarction. However, higher central systolic BP and central pulse pressure, but not brachial BP, were significantly associated with white matter hyperintensity volume.

Commentary: Acute Effects of Exercise Mode on Arterial Stiffness and Wave Reflection in Healthy Young Adults: A Systematic Review and Meta-Analysis.

We recently read the article, “Acute Effects of Exercise Mode on Arterial Stiffness and Wave Reflection in Healthy Young Adults: A Systematic Review and Meta-Analysis” by Doris R. Pierce, Kenji Doma and Anthony S. Leicht (volume 13, 2018). This particular article was a review and meta-analysis that focused on changes in arterial stiffness and measures of pulse wave reflection in response to different exercise modalities. The aim of this commentary is to highlight, and to make note, on some of the data that was presented in their manuscript. Increases in measures of pulse wave reflection, primarily the augmentation index (AIx), and the AIx at normalized to 75 beats per minute (AIx@75), are associated with increased cardiovascular mortality and morbidity (Weber et al., 2004). The AIx is defined as augmentation pressure expressed as a percentage of aortic pulse pressure. It is influenced by the timing and the amplitude of the forward traveling wave and the reflected wave (Wilkinson et al., 2000). Following resistance exercise there appears to be a significant impact on measures of pulse wave reflection (Fahs et al., 2009; Yoon et al., 2010; Kingsley et al., 2017; Tai et al., 2018). This is further supported by the meta-analysis of Pierce et al. (2018).

Augmentation index, a predictor of cardiovascular events, is increased in children and adolescents with primary nephrotic syndrome.

Arterial stiffness is associated with an increased risk of cardiovascular diseases. Augmentation index (AIx@75), a measure of arterial stiffness and wave reflection, has not been evaluated in patients with primary nephrotic syndrome (PNS). We investigated whether central and peripheral vascular profiles, hemodynamic parameters, and biochemical tests are associated with AIx@75 in PNS patients. This observational study involved 38 children and adolescents with PNS (12.14 ± 3.65years) and 37 healthy controls (13.28 ± 2.80years). Arterial stiffness and vascular and hemodynamic parameters were measured noninvasively using the Mobil-O-Graph® (IEM, Stolberg, Germany). In the PNS group, biochemical tests and corticosteroid dosage/treatment time were analyzed. Peripheral and central systolic blood pressure (SBPp, SBPc) Z-scores were significantly higher in the PNS patients. AIx@75 was significantly higher in the PNS patients (25.14 ± 9.93%) than in controls (20.84 ± 7.18%). In the control group, AIx@75 negatively correlated with weight (r = - 0.369; p = 0.025), height (r = - 0.370; p = 0.024), and systolic volume/body surface (r = - 0.448; p = 0.006). In the PNS group, a univariate linear correlation showed that AIx@75 negatively correlated with weight (r = - 0.360; p = 0.027), height (r = 0.381; p = 0.18), and systolic volume/body surface (r = - 0.447; p < 0.002) and positively with the Z-score of SBPp (r = 0.407; p = 0.011), peripheral diastolic blood pressure (DBPp, r = 0.452; p = 0.004), SBPc (r = 0.416; p = 0.009), DBPc (r = 0.407; p = 0.011), triglycerides (r = 0.525; p = 0.001), and cholesterol [total (r = 0.539; p < 0.001), LDLc (r = 0.420; p = 0.010), and non-HDLc (r = 0.511; p = 0.001)]. Early abnormalities of AIx@75 and vascular parameters suggest that patients with PNS, even in stable condition, present subclinical indicators for the development of cardiovascular disease.

Central hemodynamics in relation to low-level environmental lead exposure

Purpose: Arterial stiffness predicts cardiovascular complications. The association between arterial stiffness and blood lead (BL) remains poorly documented. We aimed to assess the association of central hemodynamic measurements, including pulse wave velocity (aPWV), with blood lead in a Flemish population.Materials and Methods: In this Flemish population study (mean age, 37.0 years; 48.3% women), 267 participants had their whole BL and 24-h urinary cadmium (UCd) measured by electrothermal atomic absorption spectrometry in 1985–2005. After 9.4 years (median), they underwent applanation tonometry to estimate central pulse pressure (cPP), the augmentation index (AI), pressure amplification (PA), and aPWV. The amplitudes of the forward (Pf) and backward (Pb) pulse waves and reflection index (RI) were derived by a pressure-based wave separation algorithm.Results: BL averaged 2.93 μg/dL (interquartile range, 1.80–4.70) and UCd 4.79 µg (2.91–7.85). Mean values were 45.0 ± 15.2 mm Hg for cPP, 24.4 ± 12.4% for AI, 1.34 ± 0.21 for PA, 7.65 ± 1.74 m/s for aPWV, 32.7 ± 9.9 mm Hg for Pf, 21.8 ± 8.4 mm Hg for Pb, and 66.9 ± 18.4% for RI. The multivariable-adjusted association sizes for a 2-fold higher BL were: +3.03% (95% confidence interval, 1.56, 4.50) for AI; −0.06 (−0.08, −0.04) for PA; 1.02 mm Hg (0.02, 2.02) for Pb; and 3.98% (1.71, 6.24) for RI (p ≤ .045). In 206 participants never on antihypertensive drug treatment, association sizes were +2.59 mm Hg (0.39, 4.79) for cPP and +0.26 m/s (0.03, 0.50) for aPWV. Analyses adjusted for co-exposure to cadmium were consistent.Conclusion: In conclusion, low-level environmental lead exposure possibly contributes to arterial stiffening and wave reflection from peripheral sites.

Nurse and Physician Perceptions of Working With Goal-Directed Therapy in the Perioperative Period

To explore nurse and physician perceptions of working with and collaborating about arterial wave analysis for goal-directed therapy to identify barriers and facilitators for use in anesthesia departments, postanesthesia care units, and intensive care units. A qualitative study drawing on ethnographic principles in a field study using the technique of nonparticipating observation and semistructured interviews. Data collection occurred using semistructured interviews with nurses (n= 23) and physicians (n= 12) and field observations in three anesthetic departments. An inductive approach for content analysis was used. The results showed one overarching theme Interprofessional collaboration encourage and impede based on three categories: (1) interprofessional and professional challenges; (2) obtaining competencies; and (3) understanding optimal fluid treatment. Several barriers identified related to interprofessional collaboration. Nurses and physicians were dependent on each other's skills and capabilities to use arterial wave analysis. Education of nurses and physicians is important to secure optimal use of goal-directed therapy.

Fitness and Fatness Are Both Associated with Cardiometabolic Risk in Preadolescents

To determine the associations between cardiorespiratory fitness (CRF) and fatness (overweight-obesity) with cardiometabolic disease risk among preadolescent children. This cross-sectional study recruited 392 children (50% female, 8-10years of age). Overweight-obesity was classified according to 2007 World Health Organization criteria for body mass index. High CRF was categorized as a maximum oxygen uptake, determined using a shuttle run test, exceeding 35mL·kg-1·minute-1 in girls and 42mL·kg-1·minute-1 in boys. Eleven traditional and novel cardiometabolic risk factors were measured including lipids, glucose, glycated hemoglobin, peripheral and central blood pressure, and arterial wave reflection. Factor analysis identified underlying cardiometabolic disease risk factors and a cardiometabolic disease risk summary score. Two-way analysis of covariance determined the associations between CRF and fatness with cardiometabolic disease risk factors. Factor analysis revealed four underlying factors: blood pressure, cholesterol, vascular health, and carbohydrate-metabolism. Only CRF was significantly (P=.001) associated with the blood pressure factor. Only fatness associated with vascular health (P=.010) and carbohydrate metabolism (P=.005) factors. For the cardiometabolic disease risk summary score, there was an interaction effect. High CRF was associated with decreased cardiometabolic disease risk in overweight-obese but not normal weight children (P=.006). Conversely, high fatness was associated with increased cardiometabolic disease risk in low fit but not high fit children (P<.001). In preadolescent children, CRF and fatness explain different components of cardiometabolic disease risk. However, high CRF may moderate the relationship between fatness and cardiometabolic disease risk. ACTRN12614000433606.

A Non-invasive Method for Determining Biomechanical Properties of the Internal Carotid Artery

ObjectivesMechanical properties of the carotid artery play an important role in the progression of arterial disease such as atherosclerosis. An early change in the mechanical properties of the arteries can be introduced as a novel risk factor for cardiovascular events. The aim of this study is to estimate, in vivo, the elastic biomechanical properties of the internal carotid wall (ICA), from the noninvasive determination of the local arterial wave speed (c). Material and methodsTo achieve this objective, c was determined from a mathematical and physical model developed in our previous work that uses the measurement of the instantaneous blood velocity at two sites by contrast magnetic resonance (PCMR), the study having been conducted on 20 healthy, young and old subjects. The determination of Young's modulus (E) requiring the measurement of the arterial radius (R) and the wall thickness (h), we first estimated the arterial compliance (C). Then from a segmentation of the PCMR image, we evaluated R and thus the elastance given by the product Eh. Finally, in front of the difficulty of measuring h, E was estimated from a statistical study on h. ResultsOur method is sensitive to a variation of the parietal elasticity as it is the case with the age. A statistical test showed that there is a very significant difference between younger and older subjects in terms of speed wave, elastance, compliance, and Young's modulus (p<0.001). Furthermore, these results, in agreement with the reference values reported in the literature, are very promising for detecting a pathological change in parietal elasticity, as is the case in atherosclerosis. ConclusionThus, the in vivo application of this technique shows its potential for clinical evaluation of arterial stiffness ICA as it is fully quantitative, non-invasive and can be performed in real time.

Effect of extension tube length on invasive blood pressure in dogs

Introduction: Extension tube length (ETL) of invasive blood pressure monitoring system affects damping in arterial wave, and proper length selection is required. This study was performed to evaluate proper ETL in dogs.

Arterial Stiffness as a Cardiovascular Risk Factor in Prostate Cancer Survivors: A Case–Control Study

In New Zealand, prostate cancer (PCa) is the most commonly diagnosed cancer in men and the third most common cause of male cancer deaths. Among these patients, the most common non-cancer related cause of death is cardiovascular disease (CVD). Aortic arterial stiffness may be clinically viable solution for detecting and tracking CVD risk factor in PCa survivors. The aim of the study was to determine whether aortic arterial stiffness is increased in PCa survivors compared to age-matched controls. Participants recruited for this prospective comparative study were PCa survivors who had completed treatment (other than endocrine therapy) or were on active surveillance compared, or were age-matched non-cancer controls. During a single 1-h appointment, all participants had measures of aortic arterial stiffness, arterial wave reflection, central blood pressure and body composition taken. Ninety-eight men were recruited, 51 PCa survivors and 47 controls. There was no significant between group difference for aortic arterial stiffness [12.0 m/s (SD: 1.7) vs. 12.0 m/s (SD: 1.9), P = 0.953, d = 0.0]. Fat free mass [60.7 kg (SD: 4.9) vs. 65.1 kg (SD: 8.3), P = 0.007, d = 0.6] and skeletal muscle index [8.6 kg/m2 (SD: 0.6) vs. 9.0 kg/m2 (SD: 0.9), P = 0.050, d = 0.5] were lower in the PCa group. Aortic arterial stiffness is not increased (worse) in men with PCa who receive various treatments, compared to age-matched controls. These findings may indicate that factors other than increased aortic arterial stiffness contribute to heightened risk of cardiovascular events in this population.

265Amyloid beta 1-40 and its upstream regulatory pathway BACE1-AS long noncoding RNA/BACE1 are associated with presence and severity of human atherosclerotic disease

Abstract Background Amyloid-beta (1-40) (Aβ1–40), a proinflammatory and pro-atherosclerotic peptide, is associated with accelerated atherosclerosis and major adverse cardiac events. Abeta1–40 production is mainly dependent on the cleavage of amyloid precursor protein by β-amyloid cleaving enzyme-1 (BACE1), known as beta-secretase. BACE1 antisense (BACE1-AS) is a long noncoding RNA that enhances BACE1 stability. Objectives To evaluate the clinical value of plasma amyloid-beta levels and its upstream regulatory pathway BACE1/BACE1-AS in patients with subclinical and established atherosclerotic cardiovascular disease. Methods Plasma levels of Aβ40 were measured in 642 consecutively recruited patients with and without clinically overt coronary artery disease (CAD). BACE1-AS lncRNA and BACE1 mRNA expression were measured in peripheral blood mononuclear cells derived from 214 study participants. Intima-media thickness and atheromatous plaques by ultrasonography, markers of arterial wave reflections and pulse wave velocity were used as surrogate markers of subclinical CVD. Cardiovascular risk factors (CVRFs), including impaired glomerular filtration rate (&lt;60 ml/min), smoking, hypertension, hyperlipidemia, diabetes, obesity and increased hsCRP (&gt;2 mg/l) were assessed as a measure of CVRF burden. Results Both in non-CAD (n=369) and CAD (n=273) patients, Aβ1–40 was associated with age, aortic and peripheral systolic and pulse pressure, and low GFR (p&lt;0.05 for all). In non-CAD subjects Aβ1–40 also correlated with diabetes and low HDL. Importantly, Aβ1–40 was associated with the presence of any plaque in subjects without CAD (p=0.035) and with increased number of diseased coronary arteries (p=0.022) independently of age, gender and CVRFs. Aβ1–40 plasma levels were increased in the highest tertile of BACE1 and BACE1AS (p&lt;0.05) while their expression levels were highly intercorrelated (r=0.825, P&lt;0.001). BACE1 and BACE1-AS levels progressively increased across the 3 groups of non-CAD (n=145), stable CAD (n=43) and acute myocardial infarction (n=26) patients (p for trend&lt;0.001). Among non-CAD subjects, both BACE1 and BACE1-AS were increased in individuals with &gt;2 CVRFs. Among CAD patients, BACE1-AS was associated with decreased LVEF (&lt;50%) (adjusted OR=1.92 per 1-SD increase, p=0.047) while BACE1 in the highest tertile was associated with 5-fold higher odds for coronary multi-vessel disease (p=0.004) after adjustment for age, gender and CVRFs. Conclusions Circulating Aβ1–40 and increased expression of its upstream regulators BACE1/BACE1-AS are intercorrelated and associated with the presence and severity of subclinical and clinically overt atherosclerosis. These findings suggest that BACE1-AS/BACE1-mediated increased availability of Aβ1–40 may play a pivotal role in its adverse cardiovascular effects.