Search

as Each artery conduces blood (conduit function, CF) and smoothes out the pulsatility (buffering function, BF), while keeping its wall protected against the high oscillations of the pulse waves (damping function, ξ). These functions depend on each segment viscoelasticity and capability to store and dissipate energy. When a graft/prosthesis is implanted, the physiological gradual transition in the viscoelasticity and functionality of adjacent arterial segments is disrupted. It remains to be elucidated if the cryografts would allow keeping the physiological biomechanical transition. The aim of this study was to evaluate the cryografts capability to reproduce the functional, energetic and reflection properties of patients' arteries and fresh homografts. Common carotid's pressure, diameter and wallthickness were recorded in vivo (15 patients) and in vitro (15 cryografts and 15 fresh homografts from donors). Calculus: elastic (Epd) and viscous (Vpd) indexes, CF, BF, dissipated (WD) and stored (WPS) energy and ξ. The graft-patient's artery matching was evaluated using the reflection coefficient (Γ) and reflected power (WΓ). Cryografts did not show differences in Epd, Vpd, BF, CF, WD, WPS, and ξ, in respect to fresh homografts and patients' arteries, ensuring a reduced Γ and WΓ. Cryografts could be considered as alternatives in arterial reconstructions since they ensure the gradual transition of patients' arteries biomechanical and functional behavior. [ABSTRACT FROM AUTHOR]

Background: Systolic blood pressure amplification (SBPA) and pulse pressure amplification (PPA) can independently predict cardiovascular damage and mortality. A wide range of methods are used for the non-invasive estimation of SBPA and PPA. The most accurate non-invasive method for obtaining SBPA and/or PPA remains unknown., Aim: This study aims to evaluate the agreement between the SBPA and PPA values that are invasively and non-invasively obtained using different (1) measurement sites (radial, brachial, carotid), (2) measuring techniques (tonometry, oscillometry/plethysmography, ultrasound), (3) pulse waveform analysis approaches, and (4) calibration methods [systo-diastolic vs. approaches using brachial diastolic and mean blood pressure (BP)], with the latter calculated using different equations or measured by oscillometry., Methods: Invasive aortic and brachial pressure (catheterism) and non-invasive aortic and peripheral (brachial, radial) BP were simultaneously obtained from 34 subjects using different methodologies, analysis methods, measuring sites, and calibration methods. SBPA and PPA were quantified. Concordance correlation and the Bland-Altman analysis were performed., Results: (1) In general, SBPA and PPA levels obtained with non-invasive approaches were not associated with those recorded invasively. (2) The different non-invasive approaches led to (extremely) dissimilar results. In general, non-invasive measurements underestimated SBPA and PPA; the higher the invasive SBPA (or PPA), the greater the underestimation. (3) None of the calibration schemes, which considered non-invasive brachial BP to estimate SBPA or PPA, were better than the others. (4) SBPA and PPA levels obtained from radial artery waveform analysis (tonometry) (5) and common carotid artery ultrasound recordings and brachial artery waveform analysis, respectively, minimized the mean errors., Conclusions: Overall, the findings showed that (i) SBPA and PPA indices are not "synonymous" and (ii) non-invasive approaches would fail to accurately determine invasive SBPA or PPA levels, regardless of the recording site, analysis, and calibration methods. Non-invasive measurements generally underestimated SBPA and PPA, and the higher the invasive SBPA or PPA, the higher the underestimation. There was not a calibration scheme better than the others. Consequently, our study emphasizes the strong need to be critical of measurement techniques, to have methodological transparency, and to have expert consensus for non-invasive assessment of SBPA and PPA., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Zócalo, Bia, Sánchez, Lev, Mendiz, Ramirez and Cabrera-Fischer.)

Background: Recently it has been proposed a new approach to estimate aortic systolic blood pressure (aoSBP) without the need for specific devices, operator-dependent techniques and/or complex wave propagation models/algorithms. The approach proposes aoSBP can be quantified from brachial diastolic and mean blood pressure (bDBP, bMBP) as: aoSBP = bMBP 2 /bDBP. It remains to be assessed to what extent the method and/or equation used to obtain the bMBP levels considered in aoSBP calculation may affect the estimated aoSBP, and consequently the agreement with aoSBP invasively recorded., Methods: Brachial and aortic pressure were simultaneously obtained invasively (catheterization) and non-invasively (brachial oscillometry) in 89 subjects. aoSBP was quantified in seven different ways, using measured (oscillometry-derived) and calculated (six equations) mean blood pressure (MBP) levels. The agreement between invasive and estimated aoSBP was analyzed (Concordance correlation coefficient; Bland-Altman Test)., Conclusions: The ability of the equation "aoSBP = MBP 2 /DBP" to (accurately) estimate (error <5 mmHg) invasive aoSBP depends on the method and equation considered to determine bMBP, and on the aoSBP levels (proportional error). Oscillometric bMBP and/or approaches that consider adjustments for heart rate or a form factor ∼40% (instead of the usual 33%) would be the best way to obtain the bMBP levels to be used to calculate aoSBP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Bia, Salazar, Cinca, Gutierrez, Facta, Zócalo and Diaz.)

The following article highlights the need for methodological transparency and consensus for an accurate and non-invasive assessment of central aortic blood pressure (aoBP), which would contribute to increasing its validity and value in both clinical and physiological research settings. The recording method and site, the mathematical model used to quantify aoBP, and mainly the method applied to calibrate pulse waveforms are essential when estimating aoBP and should be considered when analyzing and/or comparing data from different works, populations and/or obtained with different approaches. Up to now, many questions remain concerning the incremental predictive ability of aoBP over peripheral blood pressure and the possible role of aoBP-guided therapy in everyday practice. In this article, we focus on "putting it on the table" and discussing the main aspects analyzed in the literature as potential determinants of the lack of consensus on the non-invasive measurement of aoBP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Diaz, Zócalo, Salazar and Bia.)

The use of oscillometric methods to determine brachial blood pressure (bBP) can lead to a systematic underestimation of the invasively measured systolic (bSBP) and pulse (bPP) pressure levels, together with a significant overestimation of diastolic pressure (bDBP). Similarly, the agreement between brachial mean blood pressure (bMBP), invasively and non-invasively measured, can be affected by inaccurate estimations/assumptions. Despite several methodologies that can be applied to estimate bMBP non-invasively, there is no consensus on which approach leads to the most accurate estimation. Aims: to evaluate the association and agreement between: (1) non-invasive (oscillometry) and invasive bBP; (2) invasive bMBP, and bMBP (i) measured by oscillometry and (ii) calculated using six different equations; and (3) bSBP and bPP invasively and non-invasively obtained by applanation tonometry and employing different calibration methods. To this end, invasive aortic blood pressure and bBP (catheterization), and non-invasive bBP (oscillometry [Mobil-O-Graph] and brachial artery applanation tonometry [SphygmoCor]) were simultaneously obtained (34 subjects, 193 records). bMBP was calculated using different approaches. Results: (i) the agreement between invasive bBP and their respective non-invasive measurements (oscillometry) showed dependence on bBP levels (proportional error); (ii) among the different approaches used to obtain bMBP, the equation that includes a form factor equal to 33% (bMBP = bDBP + bPP/3) showed the best association with the invasive bMBP; (iii) the best approach to estimate invasive bSBP and bPP from tonometry recordings is based on the calibration scheme that employs oscillometric bMBP. On the contrary, the worst association between invasive and applanation tonometry-derived bBP levels was observed when the brachial pulse waveform was calibrated to bMBP quantified as bMBP = bDBP + bPP/3. Our study strongly emphasizes the need for methodological transparency and consensus for non-invasive bMBP assessment.

Background: The non-invasive estimation of aortic systolic (aoSBP) and pulse pressure (aoPP) is achieved by a great variety of devices, which differ markedly in the: 1) principles of recording (applied technology), 2) arterial recording site, 3) model and mathematical analysis applied to signals, and/or 4) calibration scheme. The most reliable non-invasive procedure to obtain aoSBP and aoPP is not well established. Aim: To evaluate the agreement between aoSBP and aoPP values invasively and non-invasively obtained using different: 1) recording techniques (tonometry, oscilometry/plethysmography, ultrasound), 2) recording sites [radial, brachial (BA) and carotid artery (CCA)], 3) waveform analysis algorithms (e.g., direct analysis of the CCA pulse waveform vs. peripheral waveform analysis using general transfer functions, N-point moving average filters, etc.), 4) calibration schemes (systolic-diastolic calibration vs. methods using BA diastolic and mean blood pressure (bMBP); the latter calculated using different equations vs. measured directly by oscillometry, and 5) different equations to estimate bMBP (i.e., using a form factor of 33% ("033"), 41.2% ("0412") or 33% corrected for heart rate ("033HR"). Methods: The invasive aortic (aoBP) and brachial pressure (bBP) (catheterization), and the non-invasive aoBP and bBP were simultaneously obtained in 34 subjects. Non-invasive aoBP levels were obtained using different techniques, analysis methods, recording sites, and calibration schemes. Results: 1) Overall, non-invasive approaches yielded lower aoSBP and aoPP levels than those recorded invasively. 2) aoSBP and aoPP determinations based on CCA recordings, followed by BA recordings, were those that yielded values closest to those recorded invasively. 3) The "033HR" and "0412" calibration schemes ensured the lowest mean error, and the "033" method determined aoBP levels furthest from those recorded invasively. 4) Most of the non-invasive approaches considered overestimated and underestimated aoSBP at low (i.e., 80 mmHg) and high (i.e., 180 mmHg) invasive aoSBP values, respectively. 5) The higher the invasively measured aoPP, the higher the level of underestimation provided by the non-invasive methods. Conclusion: The recording method and site, the mathematical method/model used to quantify aoSBP and aoPP, and to calibrate waveforms, are essential when estimating aoBP. Our study strongly emphasizes the need for methodological transparency and consensus for the non-invasive aoBP assessment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Bia, Zócalo, Sánchez, Lev, Mendiz, Pessana, Ramirez and Cabrera-Fischer.)

Background: Increased wave reflections assessed by pulse wave analysis (PWA) was proposed as one of the potential culprits of hypertension seen in women with pregnancy-associated hypertension (PAH). However, this statement has never been confirmed with "Wave Separation Analysis" (WSA), a more sophisticated mathematical approach that analyzes the amplitude and interaction between forward and backward aortic pressure waveform components., Objective: To characterize potential changes in pressure wave components of PAH compared to healthy non-pregnant (NP) women and women with normal pregnancies (HP) by using WSA and compared these findings with PWA-derived indexes; secondarily, to evaluate differences in WSA-derived indexes between subgroups of PAH (i.e., preeclampsia [PE] and gestational hypertension [GH])., Methods: Using radial and carotid applanation tonometry, we quantified in HP ( n = 10), PAH ( n = 16), and NP ( n = 401): (i) PWA-derived indexes; (ii) WSA-derived indexes: forward (Pf) and backward (Pb) waveform components, backward component arrival time (PbAT), reflection magnitude (RM = Pb/Pf) and index [RIx = Pb/(Pf + Pb)]., Results: While PAH was associated with a higher Pf compared to HP and NP, Pb and PbAT were similar between the groups. Both GH and PE showed a higher Pf compared to HP, but only PE had a trend of presenting with higher Pb and lower PbAT compared to the other groups. Finally, PAH showed a trend of having lower RM and RIx compared to NP and HP, with no differences between GH and PE., Conclusion: PAH was associated with higher Pf, but not higher Pb, compared to NP and HP, although PE also demonstrated a trend of higher Pb., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Pereira, Torrado, Bock, Sosa, Diaz, Bia and Zócalo.)

Bioelectrical impedance analysis (BIA)-derived indexes [e.g., fat (FMI) and fat-free mass indexes (FFMI), visceral fat level (VFL)] are used to characterize obesity as a cardiovascular risk factor (CRF). The BIA-derived index that better predicts arterial variability is still discussed., Aims: To determine: (1) the association of classical [weight, height, body mass index (BMI), basal metabolic rate (BMR)] and BIA-derived indexes, with arterial properties deviations from expected values (arterial z-scores); (2) maximum arterial variations attributable to BIA-derived indexes; (3) whether the composition of total body, trunk and/or limbs is most closely associated with arterial variations., Methods: Hemodynamic, structural, and functional parameters of different histological types of arteries were assessed ( n = 538, 7-85 years). Classical and BIA-derived indexes [fat mass and percentage, FMI, VFL, muscle mass percentage (PMM), FFMI, and percentage] were measured (mono- and multi-segmental devices). Arterial z-scores were obtained using age-related equations derived from individuals not-exposed to CRFs ( n = 1,688)., Results: First, regardless of the classical index considered, the associations with the arterial properties showed a specific hierarchy order: diameters and local stiffness > aortic and brachial blood pressure (BP) > regional stiffness. Second, all the associations of FMI and FFMI with z-scores were positive. Third, FFMI exceeded the association obtained with BMI and BMR, considering structural z-scores. In contrast, FMI did not exceed the association with z-scores achieved by BMI and BMR. Fourth, regardless of CRFs and classical indexes, arterial z-scores would be mainly explained by FFMI, VFL, and PMM. Fifth, regardless of the body-segment considered, the levels of association between FMI and z-scores did not exceed those found for classic and FFMI. Total fat mass and trunk indexes showed a greater strength of association with z-scores than the FMI of limbs. Sixth, compared to lower limb FFMI indexes, total and upper limbs FFMI showed higher levels of association with z-scores., Conclusions: FFMI (but not FMI) exceeded the strength of association seen between BMI or BMR and structural z-scores. Regardless of the body segment analyzed, the associations between FMI and z-scores did not exceed those found with classic and FFMI. Arterial z-scores could be independently explained by FFMI, VFL, and PMM., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Gómez-García, Torrado, Pereira, Bia and Zócalo.)

Background: It remains to be established to what extent physical activity (PA) levels among individuals are independently associated with deviations from the "optimal" state of the arterial system. Accelerometers have been proposed as means to obtain reliable, objective, and more comprehensive data of PA. Decisions at the time of data collection/processing could influence the association between accelerometry-derived indices and arterial properties., Objectives: (i) To identify to what extent the strength of association between arterial properties and accelerometer-derived indices depend on the recording site and/or the epoch length; (ii) to determine whether some arterial characteristics (hemodynamic vs. structural vs. functional) or regions (elastic vs. transitional vs. muscular arteries; central vs. peripheral) have higher levels of association with accelerometry-derived indices., Methods: Physical activity (PA), cardiovascular risk factors (CRFs), and cardiovascular properties were evaluated in 60 volunteers (general population; age: 23-62 years; women: 43%). PA was measured daily for 7 days (free-living situation; triaxial-accelerometers ActiGraph-GT3X+; hip and wrist; "Worn-to-wrist" option) and raw data was converted at epoch lengths of 1, 5, 10, 30, and 60-s. PA-related energy expenditure, daily time in moderate-to-vigorous PA, steps/minute, and counts-per-minute for vector magnitude were calculated. The cardiovascular evaluation included hemodynamic (central and peripheral pressure), structural (diameters and intima-media thickness), and functional (local and regional stiffness) parameters of carotids, femoral, and brachial arteries, and carotid-femoral and carotid-radial pathways. Arterial z-scores were obtained using age-related equations derived from healthy participants not exposed to CRFs ( n = 1,688; age: 2-84 years; female: 51.2%) to evaluate at which degree each parameter deviates from the "optimal" value., Methods: In general, hip recordings outperformed those obtained on the wrist regarding the strength of association with arterial parameters. Accelerometer-derived indices and their association with arterial properties vary depending on the recording site and epoch length. PA indices are stronger associated with functional (local) than structural variables and with central than peripheral arteries., Conclusions: Regardless of the PA index, there were independent associations with central artery characteristics, which reinforces that these territories would be the most related to PA levels. Differences in data acquisition and processing could lead to differences in conclusions when addressing the association between accelerometer-derived indices and the cardiovascular system., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Gómez-García, Torrado, Bia and Zócalo.)

Background: Compliance with physical activity recommendations (CPARs) is associated with better health indicators. However, there are only few studies to date that have comprehensively analyzed the association between CPARs and cardiovascular status "as a whole" (e.g., analyzing hemodynamic, structural, and functional properties, and different arterial territories). The relationship between CPARs and cardiovascular properties could be strongly influenced by the growth and aging process., Aim: The goal of the study is to investigate the association between CPAR and cardiovascular properties by placing special emphasis on: (i) identifying if there is an independent association, (ii) if the association is "moderated" by age, and (iii) to what extent the association depends on the arterial parameter (hemodynamic vs. structural vs. functional) and/or the arterial segment (e.g., central vs. peripheral; elastic vs. transitional vs. muscular arteries)., Methods: A total of 3,619 subjects (3-90 years of age) were studied. Extensive cardiovascular evaluations were performed. Cardiovascular risk factors (CRFs) and physical activity (PA) levels were determined. The subjects were categorized as compliant ( n = 1, 969) or non-compliant ( n = 1,650) with World Health Organization-related PA recommendations. Correlation and multiple regression models (including CPAR * Age interaction) were obtained, and Johnson-Neyman technique was used to produce regions of significance., Results: The independent association between CPARs and cardiovascular characteristics were strongly moderated by age. The moderation was observed on a wide range of age but particularly notorious on the extremes of life. Certain arterial characteristics demonstrated opposite effects in relation to CPAR status depending on the range of age considered. The association between CPAR and cardiovascular characteristics was independent of CRFs and moderated by age. In subjects younger than 45-55 years, CPAR status was associated with lower central and peripheral blood pressure (i.e., the younger the subject, the higher the reduction). During adult life, as age increases in the subjects, CPARs was associated with a beneficial hemodynamic profile, which is not related with variations in pressure but strongly related with lower levels of waveform-derived indexes and ventricular afterload determinants., Conclusions: The independent associations between CPARs and arterial properties were strongly moderated by age. Data provided by blood pressure levels and waveform-derived indexes would be enough to evaluate the independent association between CPARs and the vascular system in the general population., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zócalo, Gómez-García, Torrado and Bia.)

Aortic blood pressure (aoBP) waveform-derived indexes could provide valuable (prognostic) information over and above cardiovascular risk factors (CRFs). To obtain aoBP waveform-characteristics, several (i) techniques, (ii) recording sites, (iii) pressure-only waveform analysis mathematical approaches [e.g., pulse wave analysis (PWA), wave separation analysis (WSA)], and (iv) indexes [augmentation pressure and index (AP and AIx), forward (Pf) and backward (Pb) components of aoBP, reflection magnitude (RM), and reflection index (Rix)], were proposed. An accurate clinical use of these indexes requires knowing their physiological age-related profiles and the expected values for a specific subject. There are no works that have characterized waveform-derived indexes profiles in large populations considering: (i) as a continuous, data from different age stages (childhood, adolescence, and adulthood), (ii) complementary indexes, (iii) data obtained from different techniques and approaches, and (iv) analyzing potential sex- and body height (BH)-related differences. In addition, (v) there is a lack of normative data (reference intervals, RIs) for waveform-derived indexes., Aims: (1) to evaluate the association and agreement between PWA- and/or WSA-derived indexes obtained with different techniques and approaches; (2) to determine the need for sex-, BH-, and/or age-specific RIs; (3) to define RIs for PWA- and WSA-derived indexes in a large cohort of healthy children, adolescents, and adults., Methods: 3619 subjects (3-90 y) were included; 1688 healthy (2-84 y). AP, AIx, AIx@75, Pf, Pb, RM, and RIx were obtained (carotid and radial tonometry, brachial oscillometry/plethysmography). The association and agreement between indexes were analyzed (Concordance correlation coefficients, Bland-Altman analysis). Mean and SD equations and sex-specific BH- and age-related profiles were obtained (regression methods; fractional polynomials)., Results: Waveform-derived indexes were not equivalent; for a specific index, there were systematic and proportional differences associated with the recording site (e.g., carotid vs. radial) and technique (e.g., tonometry vs. oscillometry). The need for sex-, BH-, or age-specific RIs was dependent on the index and/or age considered. RIs were defined for each index considering differences between recording sites and techniques. Equations for waveform-derived indexes age-related profiles were included, enabling to determine for a specific subject, the expected values and potential data deviations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zócalo and Bia.)

Background: Non-pregnant (NP) women have a progressive increase in arterial stiffness from central-to-peripheral arteries ["stiffness gradient" (SG)], which is of physiologic importance since excessive pulsatility is filtered by the creation of wave reflections. If the aorta gets stiff with minimal or no change in the periphery, the SG is dissipated transmitting pressure disturbances to the microcirculation. It remains unknown the status of the SG in both women with healthy pregnancies (HP) and complicated by pregnancy-associated hypertension (PAH). Objective: To determine whether HP and PAH are associated with changes in SG. Secondarily, we aim at identifying potential differences between the subgroups of PAH (pre-eclampsia and gestational hypertension). Methods: HP ( n = 10), PAH ( n = 16), and healthy NP women ( n = 401, to be matched for age, and cardiovascular risk with the pregnant women) were included. Carotid-to-femoral (cfPWV) and carotid-to-radial pulse wave velocity (crPWV), common carotid artery (CCA) and brachial artery (BA) diameters and elastic modulus (EM), and regional (cfPWV/crPWV or "PWV ratio") and local (CCA EM/BA EM or "EM ratio") SG were quantified. Results: HP showed no changes in PWV ratio compared with NP, in the presence of significantly lower cfPWV and crPWV. HP exhibited higher arterial diameters and lower CCA EM/BA EM compared to NP, without differences with PAH. PAH was associated with a significant increase in the PWV ratio that exceeded the levels of both NP and HP, explained by a lower (although significant) reduction of cfPWV with respect to that observed in HP with respect to NP, and a higher reduction in crPWV with respect to that observed between HP and NP. The blunted reduction in cfPWV observed in PAH coincided with an increase in the CCA EM. Conclusions: Compared with NP, HP was associated with unchanged PWV ratio but with a reduction in CCA EM/BA EM, in the setting of a generalized drop in arterial stiffness. Compared with NP and HP, PAH was associated with an "exaggerated rise" in the PWV ratio without changes in CCA EM/BA EM, in the setting of a blunt reduction in cfPWV but exaggerated crPWV drop. The SG attenuation/reversal in PAH was mainly driven by pre-eclampsia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Pereira, Torrado, Sosa, Diaz, Bia and Zócalo.)

Background: There are scarce and controversial data on whether human immunodeficiency virus (HIV) infection is associated with changes in aortic pressure (aoBP) and waveform-derived indexes. Moreover, it remains unknown whether potential differences in aoBP and waveform indexes between people living with HIV (PLWHIV) and subjects without HIV (HIV-) would be affected by the calibration method of the pressure waveform. Aims: To determine: (i) whether PLWHIV present differences in aoBP and waveform-derived indexes compared to HIV- subjects; (ii) the relative impact of both HIV infection and cardiovascular risk factors (CRFs) on aoBP and waveform-derived indexes; (iii) whether the results of the first and second aims are affected by the calibration method. Methods: Three groups were included: (i) PLWHIV (n = 86), (ii) HIV- subjects (general population; n = 1,000) and (iii) a Reference Group (healthy, non-exposed to CRFs; n = 398). Haemodynamic parameters, brachial pressure (baBP; systolic: baSBP; diastolic: baDBP; mean oscillometric: baMBPosc) and aoBP and waveform-derived indexes were obtained. Brachial mean calculated (baMBPcalc=baDBP+[baSBP-baDBP]/3) pressure was quantified. Three waveform calibration schemes were used: systolic-diastolic, calculated (baMBPcalc/baDBP) and oscillometric mean (baMBPosc/baDBP). Results: Regardless of CRFs and baBP, PLWHIV presented a tendency of having lower aoBP and waveform-derived indexes which clearly reached statistical significance when using the baMBPosc/baDBP or baMBPcalc/baDBP calibration. HIV status exceeded the relative weight of other CRFs as explanatory variables, being the main explanatory variable for variations in central hemodynamics when using the baMBPosc/baDBP, followed by the baMBPcalc/baDBP calibration. Conclusions: The peripheral waveform calibration approach is an important determinant to reveal differences in central hemodynamics in PLWHIV., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Diaz, Grand, Torrado, Salazar, Zócalo and Bia.)

Ultrasound-derived blood flow velocity (BFV) levels [e.g., peak systolic velocity (PSV)], intrabeat indexes (e.g., resistive), and intersegment ratios [e.g., internal/common carotid artery (ICA/CCA) PSV ratio] are assessed to describe cardiovascular physiology and health status (e.g., disease severity evaluation and/or risk stratification). In this respect, fixed cut-off values (disregard of age or sex) have been proposed to define "significant" vascular disease from BFV-derived data (parameters). However, the use of single fixed cut-off values has limitations. Accurate use of BFV-derived parameters requires knowing their physiological age-related profiles and the expected values for a specific subject. To our knowledge, there are no studies that have characterized BFV profiles in large populations taking into account: (i) data from different age-stages (as a continuous) and transitions (childhood-adolescence-adulthood), (ii) complementary parameters, (iii) data from different arteries, and (iv) potential sex- and hemibody-related differences. Furthermore, (v) there is little information regarding normative data [reference intervals (RIs)] for BFV indexes. Aims: The aims of this study are the following: (a) to determine the need for age-, body side-, and sex-specific profiles for BFV levels and derived parameters (intrabeat indexes and intersegment ratios), and (b) to define RIs for BFV levels and parameters, obtained from CCA, ICA, external carotid, vertebral, femoral, and brachial arteries records. Methods: A total of 3,619 subjects (3-90 years) were included; 1,152 were healthy (without cardiovascular disease and atheroma plaques) and non-exposed to cardiovascular risk factors. BFV data were acquired. The agreement between left and right data was analyzed (Concordance correlation, Bland-Altman). Mean and SD equations and age-related profiles were obtained for BFV levels and parameters (regression methods; fractional polynomials). Results: Left and right body-side derived data were not always equivalent. The need for sex-specific RIs was dependent on the parameter and/or age considered. RIs were defined for each studied artery and parameter. Percentile curves were compared with recommended fixed cut-off points. The equations for sex, body-side, and age-specific BFV physiological profiles obtained in the large population (of children, adolescents, and adults) studied were included (spreadsheet formats), enabling to determine for a particular subject, the expected values and potential data deviations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zócalo and Bia.)

Vascular reactivity (VR), defined as blood vessels' capability to actively modify the diameter and flow resistances can be non-invasively assessed analyzing vascular response to forearm occlusion. Several VR indexes can be quantified: (i) ´microvascular´, which consider variables that depend almost exclusively on changes in distal resistances, (ii)´ macrovascular´, that evaluate the changes in brachial artery (BA) diameter, adjusting for blood flow stimulus, and (iii) ´macro/micro´, whose values depend on the micro and macrovascular response without discriminating each one´s contribution. VR indexes could not be associated. Many VR indexes have been used without availability of adequate normative data (reference intervals, RIs)., Aims: (1) to evaluate macro, macro/micro and micro VR indexes obtained in a cohort of healthy children, adolescents and adults, (2) to evaluate the association between VR indexes, (3) to determine the need for age and/or sex-specific RIs, and (4) to define RIs for VR indexes., Methods: Ultrasound (B-mode/Doppler) and automatic computerized analysis were used to assess BA diameter, blood flow velocity and distal resistances, at rest and in conditions of decreased and increased blood flow. Macro, macro/micro and micro VR indexes were quantified (n = 3619). RIs-subgroups were defined according to European Reference Values for Arterial Measurements Collaboration Group (n = 1688, 3-84 years) and HUNT3-Fitness Study Group (n = 2609, 3-85 years) criteria. Mean value and standard deviation equations were obtained for VR indexes. The need for age or sex-specific RIs was analyzed. Percentile curves were defined and data were compared with those obtained in other populations., Conclusion: Macro and macro/micro VR indexes showed no association (or it was very weak) with microvascular indexes. Age- and sex-related profiles and RIs for macro, macro/micro and micro VR indexes were defined in a large population of healthy subjects (3-85 y). Equations for mean, standard deviation and percentiles values (year-to-year) were included in text and spreadsheet formats., Competing Interests: The authors have declared that no competing interests exist.

An association between movement behavior (MB) components (sleep time (ST), physical activity (PA) and sedentary behavior (SB)) and the state of the cardiovascular (CV) system in children has been postulated. However, it is still controversial whether MB components and/or sub-components (domains) during childhood are independently associated with aortic and peripheral blood pressure (BP), and structural or functional arterial properties., Aims: (1) to evaluate MB components and subcomponents associations with CV characteristics, (2) to analyze the explanatory capacity of interindividual variations in MB on CV properties inter-individual variations at the beginning of school age., Methods: Anthropometric, aortic and peripheral BP, hemodynamic levels (cardiac output, systemic vascular resistances), wave reflection indexes, and arterial structural (diameter, intima-media thickness) and functional (blood flow velocities, Doppler-indexes, local and regional arterial stiffness) parameters of elastic (carotids), transitional (brachial) and muscular (femoral) arteries and time spent in MB (PA questionnaires) were assessed in 816 children (5-6 years). Cardiovascular variables were standardized (z-scores), using age- and sex-related mean values and standard deviations obtained from subjects non-exposed to CV risk factors (CRFs) and who complied with 24 h MB recommendations (reference subgroup). Multiple linear regression models were constructed considering the CV z-scores as dependent variables and CRFs and MB components and subcomponents as independent variables., Results: CV variables showed independent association with MB variations. However, their explanatory capacity on CV characteristics was lesser than that of anthropometric indexes, sex and/or high BP., Conclusions: MB components and sub-components were associated with CV characteristics regardless of other factors, but their capacity to explain variations was lesser than that of anthropometric data, sex or high BP state. MB subcomponents (e.g., sedentary play and screen time in case of SB) showed different (even opposite) associations with CV parameters. ST was associated mainly with indexes of the ventricle ejective function, rather than with CV structural characteristics. SB component and subcomponents were associated with BP, but not with structural parameters. PA component and subcomponents were associated with both BP and structural parameters. The different arterial types, as well central and peripheral parameters showed independent associations with MB components and subcomponents. None of these were independently associated with arterial stiffness.

Preeclampsia is a worldwide pregnancy complication with serious short- and long-term maternal and neonatal consequences. Our understanding of preeclampsia pathophysiology has significantly evolved over the last decades with the recognition that impaired arterial function and structure may occur early in the course of pregnancy, preceding the clinic-humoral syndrome and driving long-term cardiovascular disease risk in the future of these patients. Although an early abnormal placentation may be the inciting event for a large proportion of cases, there is growing evidence that challenges the placental hypothesis in all affected women, since placental histopathology lesions thought to be characteristic are neither sensitive nor specific markers for the disorder. Recent hemodynamic investigations and studies on left ventricular function and structure in women with preeclampsia further challenge this universal paradigm and propose that placental dysfunction could be secondary to a maternal cardiovascular maladaptation to pregnancy in certain patients. Supporting this hypothesis, certain vascular features, which are characteristically enhanced in normal pregnancy allowing a healthy vascular adaptation, are absent in preeclampsia and comparable to the nonpregnant population. However, arterial biomechanics in preeclampsia may only not cope with hemodynamic demands of pregnancy but also impose additional detrimental loads to the maternal heart ("impaired left-ventricle-aorta coupling") and transmit pressure and flow disturbances into the fetoplacental circulation ("impaired large arteries-microcirculation coupling"). In this review, we analyze the major role of the arterial dysfunction in the cardiovascular maladaptation hypothesis of preeclampsia, shed light on its potential etiopathogenic link, and discuss the complementary nature of the placental and cardiovascular theories.

Nutritional status in early life stages has been associated with arterial parameters in childhood. However, it is still controversial whether changes in standardized body weight (z-BW), height (z-BH), BW for height (z-BWH) and/or body mass index (z-BMI) in the first three years of life are independently associated with variations in arterial structure, stiffness and hemodynamics in early childhood. In addition, it is unknown if the strength of the associations vary depending on the growth period, nutritional characteristics and/or arterial parameters analyzed., Aims: First, to compare the strength of association between body size changes (Δz-BW, Δz-BH, Δz-BWH, Δz-BMI) in different time intervals (growth periods: 0-6, 0-12, 0-24, 0-36, 12-24, 12-36, 24-36 months (m)) and variations in arterial structure, stiffness and hemodynamics at age 6 years. Second, to determine whether the associations depend on exposure to cardiovascular risk factors, body size at birth and/or on body size at the time of the evaluation (cofactors). Anthropometric (at birth, 6, 12, 24, 36 m and at age 6 years), hemodynamic (peripheral and central (aortic)) and arterial (elastic (carotid) and muscular (femoral) arteries; both hemi-bodies) parameters were assessed in a child cohort (6 years; n =632). The association between arterial parameters and body size changes (Δz-BW, Δz-BH, Δz-BWH, Δz-BMI) in the different growth periods was compared, before and after adjustment by cofactors., Results: Δz-BW 0-24 m and Δz-BWH 0-24 m allowed us to explain inter-individual variations in structural arterial properties at age 6 years, with independence of cofactors. When the third year of life was included in the analysis (0-36, 12-36, 24-36 m), Δz-BW explained hemodynamic (peripheral and central) variations at age 6 years. Δz-BH and Δz-BMI showed limited associations with arterial properties., Conclusion: Δz-BW and Δz-BWH are the anthropometric variables with the greatest association with arterial structure and hemodynamics in early childhood, with independence of cofactors.

In addition to being a marker of cardiovascular (CV) aging, aortic stiffening has been shown to be independently associated with increased CV risk (directly and/or indirectly due to stiffness-gradient attenuation). Arterial stiffness determines the rate at which the pulse pressure wave propagates (i.e., pulse wave velocity, PWV). Thus, propagated PWV (i.e., the distance between pressure-wave recording sites divided by the pulse transit time) was proposed as an arterial stiffness index. Presently, aortic PWV is considered a gold-standard for non-invasive stiffness evaluation. The limitations ascribed to PWV have hampered its use in clinical practice. To overcome the limitations, different approaches and parameters have been proposed (e.g., local PWV obtained by wave separation and pulse wave analysis). In turn, it has been proposed to determine PWV considering blood pressure (BP) levels (β-PWV), so as to evaluate intrinsic arterial stiffness. It is unknown whether the different approaches used to assess PWV or β-PWV are equivalent and there are few data regarding age- and sex-related reference intervals (RIs) for regional and local PWV, β-PWV and PWV ratio., Aims: (1) to evaluate agreement between data from different stiffness indexes, (2) to determine the need for sex-specific RIs, and (3) to define RIs for PWV, β-PWV and PWV ratio in a cohort of healthy children, adolescents and adults., Methods: 3619 subjects (3-90 y) were included, 1289 were healthy and non-exposed to CV risk factors. Carotid-femoral (cfPWV) and carotid-radial (crPWV) PWV were measured (SphygmoCor System (SCOR)) and PWV ratio (cfPWV/crPWV) was quantified. Local aortic PWV was obtained directly from carotid waves (aoPWV-Carotid; SCOR) and indirectly (generalized transfer function use) from radial (aoPWV-Radial; SCOR) and brachial (aoPWV-Brachial; Mobil-O-Graph system (MOG)) recordings. β-PWV was assessed by means of cardio-ankle brachial (CAVI) and BP-corrected CAVI (CAVIo) indexes. Analyses were done before and after adjustment for BP. Data agreement was analyzed (correlation, Bland-Altman). Mean and standard deviation (age- and sex-related) equations were obtained for PWV parameters (regression methods based on fractional polynomials)., Results: The methods and parameters used to assess aortic stiffness showed different association levels. Stiffness data were not equivalent but showed systematic and proportional errors. The need for sex-specific RIs depended on the parameter and/or age considered. RIs were defined for all the studied parameters. The study provides the largest data set related to agreement and RIs for stiffness parameters obtained in a single population., Competing Interests: The authors declare no conflict of interest. The funders had no role in the study design; collection, analyses or interpretation of data; in the manuscript writing, nor in the decision to publish the results.

Background: Non-invasive assessment of stroke volume (SV), cardiac output (CO) and cardiac index (CI) has shown to be useful for the evaluation, diagnosis and/or management of different clinical conditions. Through pulse contour analysis (PCA) cuff‑based oscillometric devices would enable obtaining ambulatory operator-independent non-invasive hemodynamic monitoring. There are no reference intervals (RIs), when considered as a continuum in childhood, adolescence and adult life, for PCA-derived SV [SV(PCA)], CO [CO(PCA)] and CI [CI(PCA)]. The aim of the study were to analyze the associations of SV(PCA), CO(PCA) and CI(PCA) with demographic, anthropometric, cardiovascular risk factors (CVRFs) and hemodynamic parameters, and to define RIs and percentile curves for SV(PCA), CO(PCA) and CI(PCA), considering the variables that should be considered when expressing them., Methods: In 1449 healthy subjects (3-88 years) SV(PCA), CO(PCA) and CI(PCA) were non-invasively obtained (Mobil-O-Graph; Germany)., Analysis: associations between subject characteristics and SV(PCA), CO(PCA) and CI(PCA) levels (correlations; regression models); RIs and percentiles for SV(PCA), CO(PCA) and CI(PCA) (parametric methods; fractional polynomials)., Results: Sex, age, and heart rate would be explanatory variables for SV, CO, and CI levels. SV levels were also examined by body height, while body surface area (BSA) contributing to evaluation of CO and CI. CVRFs exposure did not contribute to independently explain the values of the dependent variables. SV, CO and CI levels were partially explained by the oscillometric-derived signal quality. RIs and percentiles were defined., Conclusions: Reference intervals and percentile for SV(PCA), CO(PCA) and CI(PCA), were defined for subjects from 3-88 years of age, results are expressed according to sex, age, heart rate, body height and/or BSA.

Carotid and/or femoral atherosclerotic plaques (AP) assessment through imaging studies is an interesting strategy for improving individual cardiovascular risk (CVR) stratification and cardiovascular disease (CVD) and/or events prediction. There is no consensus on who would benefit from image screening aimed at determining AP presence, burden, and characteristics., Aims: (1) to identify, in asymptomatic and non-treated subjects, demographic factors, anthropometric characteristics and cardiovascular risk factors (CRFs), individually or grouped (e.g., CVR equations, pro-atherogenic lipid ratios) associated with carotid and femoral AP presence, burden, geometry, and fibro-lipid content; (2) to identify cut-off values to be used when considering the variables as indicators of increased probability of AP presence, elevated atherosclerotic burden, and/or lipid content, in a selection scheme for subsequent image screening., Methods: CRFs exposure and clinical data were obtained ( n = 581; n = 144 with AP; 47% females). Arterial (e.g., ultrasonography) and hemodynamic (central [cBP] and peripheral blood pressure; oscillometry/applanation tonometry) data were obtained. Carotid and femoral AP presence, burden (e.g., AP number, involved territories), geometric (area, width, height) and fibro-lipid content (semi-automatic, virtual histology analysis, grayscale analysis and color mapping) were assessed. Lipid profile was obtained. Lipid ratios (Total cholesterol/HDL-cholesterol, LDL-cholesterol/HDL-cholesterol, LogTryglicerides(TG)/HDL-cholesterol) and eight 10-years [y.]/CVR scores were quantified (e.g., Framingham Risk Scores [FRS] for CVD)., Results: Age, 10-y./CVR and cBP showed the highest levels of association with AP presence and burden. Individually, classical CRFs and lipid ratios showed almost no association with AP presence. 10-y./CVR levels, age and cBP enabled detecting AP with large surfaces (˃p75th). Lipid ratios showed the largest association with AP fibro-lipid content. Ultrasound evaluation could be considered in asymptomatic and non-treated subjects aiming at population screening of AP (e.g., ˃ 45 y.; 10-y./FRS-CVD ˃ 5-8%); identifying subjects with high atherosclerotic burden (e.g., ˃50 y., 10-y./FRS-CVD ˃ 13-15%) and/or with plaques with high lipid content (e.g., LogTG/HDL ˃ 0.135)., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; data collection, analyses or interpretation; in the writing of the manuscript or in the decision to publish the results.

Non-invasive devices used to estimate central (aortic) systolic pressure (cSBP), pulse pressure (cPP) and forward (Pf) and backward (Pb) wave components from blood pressure (BP) or surrogate signals differ in arteries studied, techniques, data-analysis algorithms and/or calibration schemes (e.g. calibrating to calculated [MBPc] or measured [MBPosc] mean pressure). The aims were to analyze, in children, adolescents and young-adults (1) the agreement between cSBP, cPP, Pf and Pb obtained using carotid (CT) and radial tonometry (RT) and brachial-oscillometry (BOSC); and (2) explanatory factors for the differences between approaches-data and between MBPosc and MBPc.1685 subjects (mean/range age: 14/3-35 y.o.) assigned to three age-related groups (3-12; 12-18; 18-35 y.o.) were included. cSBP, cPP, Pf and Pb were assessed with BOSC (Mobil-O-Graph), CT and RT (SphygmoCor) records. Two calibration schemes were considered: MBPc and MBPosc for calibrations to similar BP levels. Correlation, Bland-Altman tests and multiple regression models were applied. Systematic and proportional errors were observed; errors´ statistical significance and values varied depending on the parameter analyzed, methods compared and group considered. The explanatory factors for the differences between data obtained from the different approaches varied depending on the methods compared. The highest cSBP and cPP were obtained from CT; the lowest from RT. Independently of the technique, parameter or age-group, higher values were obtained calibrating to MBPosc. Age, sex, heart rate, diastolic BP, body weight or height were explanatory factors for the differences in cSBP, cPP, Pf or Pb. Brachial BP levels were explanatory factors for the differences between MBPosc and MBPc., Competing Interests: The authors have declared that no competing interests exist.

An association between nutritional characteristics in theearlylife stages and the state of the cardiovascular (CV) system in early childhood itself and/or at the beginning of adulthood has been postulated. It is still controversial whether changes in weight, height and/or body mass index (BMI) during childhood or adolescence are independently associated with hemodynamics and/or arterial properties in early childhood and adulthood., Aims: First, to evaluate and compare the strength of association between CVproperties (at 6 and 18 years (y)) and (a) anthropometric data at specific growth stages (e.g., birth, 6 y, 18 y) and (b) anthropometric changes during early (0-2 y), intermediate (0-6 y), late (6-18 y) and global (0-18 y) growth. Second, to determine whether the associations between CVproperties and growth-related body changes depend on size at birth and/or at the time of CVstudy. Third, to analyze the capacity of growth-related body size changes to explain hemodynamic and arterial properties in early childhood and adulthood before and after adjusting for exposure to CV risk factors. Anthropometric, hemodynamic (central, peripheral) and arterial parameters (structural, functional; elastic, transitional and muscular arteries) were assessed in two cohorts (children, n = 682; adolescents, n = 340). Data wereobtained and analyzed following identical protocols., Results: Body-size changes in infancy (0-2 y) and childhood (0-6 y) showed similar strength of association with CV properties at 6 y. Conversely, 0-6, 6-18 or 0-18 ychanges were not associated with CV parameters at 18 y. The association between CV properties at 6 yand body-size changes during growth showed: equal or greater strength than the observed for body-size at birth, and lower strength compared to that obtained for current z-BMI. Conversely, only z-BMI at 18 y showed associations with CV z-scores at 18 y. Body size at birth showed almost no association with CVproperties at 6 or 18 y., Conclusion: current z-BMI showed the greatest capacity to explain variations in CV properties at 6 and 18 y. Variations in some CV parameters were mainly explained by growth-related anthropometric changes and/or by their interaction with current z-BMI. Body size at birth showed almost no association with arterial properties at 6 or 18 y.

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

There is little information regarding age-related reference intervals (RIs) of carotid-femoral pulse wave velocity (cfPWV) for large healthy populations in South America. The aims of this study were to determine cfPWV RIs and percentiles in a cohort of healthy children, adolescents, and adults and to generate year-to-year percentile curves and body-height percentile curves for children and adolescents. cfPWV was measured in 1722 healthy participants with no cardiovascular risk factors (9-87 years, 60% men). First, RIs were evaluated for males and females through correlation and covariate analysis. Then, mean and standard deviation age-related equations were obtained for cfPWV using parametric regression methods based on fractional polynomials and age-specific (year-to-year) percentile curves that were defined using the standard normal distribution. Age-specific first, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile curves were calculated. Finally, height-related cfPWV percentile curves for children and adolescents (<21 years) were established. After adjusting for age and blood pressure differences with respect to females, males showed higher cfPWV levels (6.60 vs 6.45 m/s; P < .01). Thus, specific RIs for males and females were reported. The study provides the largest database to date concerning cfPWV in healthy people from Argentina. Specific RIs and percentiles of cfPWV are now available according to age and sex. Specific percentiles of cfPWV according to body height were reported for people younger than 21 years., (©2018 Wiley Periodicals, Inc.)

Reference intervals (RIs) of carotid intima media thickness (CIMT) from large healthy population are still lacking in Latin America. The aim of this study was to determine CIMT RIs in a cohort of 1012 healthy subjects from Argentina. We evaluated if RIs for males and females and for left and right carotids were necessary. Second, mean and standard deviation (SD) age-related equations were obtained for left, right, and average (left + right)/2) CIMT using parametric regression methods based on fractional polynomials, in order to obtain age-specific percentiles curves. Age-specific percentile curves were obtained. Males showed higher A-CIMT (0.577 ± 0.003 mm versus 0.566 ± 0.004 mm, P = 0.039) in comparison with females. For males, the equations were as follows: A-CIMT mean = 0.42 + 8.14 × 10 -5 ⁎Age 2 ; A-CIMT SD = 5.9 × 10 -2 + 1.09 × 10 -5 ⁎Age 2 . For females, they were as follows: A-CIMT mean = 0.40 + 8.20 × 10 -5 ⁎Age 2 ; A-CIMT SD = 4.67 × 10 -2 + 1.63 × 10 -5 ⁎Age 2 . Our study provides the largest database concerning RIs of CIMT in healthy people in Argentina. Specific RIs and percentiles of CIMT for children, adolescents, and adults are now available according to age and gender, for right and left common carotid arteries.

Aim. To analyze if childhood obesity associates with changes in elastic, transitional, and/or muscular arteries' stiffness. Methods. 221 subjects (4-15 years, 92 females) were assigned to normal weight (NW, n = 137) or obesity (OB, n = 84) groups, considering their body mass index z-score. Age groups were defined: 4-8; 8-12; 12-15 years old. Carotid, femoral, and brachial artery local stiffness was determined through systodiastolic pressure-diameter and stress-strain relationships. To this end, arterial diameter and peripheral and aortic blood pressure (BP) levels and waveforms were recorded. Carotid-femoral, femoropedal, and carotid-radial pulse wave velocities were determined to evaluate aortic, lower-limb, and upper-limb regional arterial stiffness, respectively. Correlation analysis between stiffness parameters and BP was done. Results. Compared to NW, OB subjects showed higher peripheral and central BP and carotid and femoral stiffness, reaching statistical significance in subjects aged 12 and older. Arterial stiffness differences disappeared when levels were normalized for BP. There were no differences in intrinsic arterial wall stiffness (elastic modulus), BP stiffness relationships, and regional stiffness parameters. Conclusion. OB associates with BP-dependent and age-related increase in carotid and femoral (but not brachial) stiffness. Stiffness changes would not be explained by intrinsic arterial wall alterations but could be associated with the higher BP levels observed in obese children.

The aims were to determine if childhood obesity is associated with increased central aortic blood pressure (BP) and to characterize haemodynamic and vascular changes associated with BP changes in obese children and adolescents by means of analyzing changes in cardiac output (stroke volume, SV), arterial stiffness (aortic pulse wave velocity, PWV), peripheral vascular resistances (PVR), and net and relative contributions of reflected waves to the aortic pulse wave amplitude. We included 117 subjects (mean/range age: 10 (5-15) years, 49 females), who were obese (OB) or had normal weight (NW). Peripheral and central aortic BP, PWV, and pulse wave-derived parameters (augmentation index, amplitude of forward and backward components) were measured with tonometry (SphygmoCor) and oscillometry (Mobil-O-Graph). With independence of the presence of dyslipidemia, hypertension, or sedentarism, the aortic systolic and pulse BP were higher in OB than in NW subjects. The increase in central BP could not be explained by the elevation in the relative contribution of reflections to the aortic pressure wave and higher PVR or by an augmented peripheral reflection coefficient. Instead, the rise in central BP could be explained by an increase in the amplitude of both incident and reflect wave components associated to augmented SV and/or PWV.

Background. Adequate fluid management could be essential to minimize high arterial stiffness observed in chronically hemodialyzed patients (CHP). Aim. To determine the association between body fluid status and central and peripheral arterial stiffness levels. Methods. Arterial stiffness was assessed in 65 CHP by measuring the pulse wave velocity (PWV) in a central arterial pathway (carotid-femoral) and in a peripheral pathway (carotid-brachial). A blood pressure-independent regional arterial stiffness index was calculated using PWV. Volume status was assessed by whole-body multiple-frequency bioimpedance. Patients were first observed as an entire group and then divided into three different fluid status-related groups: normal, overhydration, and dehydration groups. Results. Only carotid-femoral stiffness was positively associated (P < 0.05) with the hydration status evaluated through extracellular/intracellular fluid, extracellular/Total Body Fluid, and absolute and relative overhydration. Conclusion. Volume status and overload are associated with central, but not peripheral, arterial stiffness levels with independence of the blood pressure level, in CHP.

Introduction. An altered endothelial function (EF) could be associated with preeclampsia (PE). However, more specific and complementary analyses are required to confirm this topic. Flow-mediated dilation (FMD), low-flow-mediated constriction (L-FMC), and hyperemic-related changes in carotid-radial pulse wave velocity (PWVcr) offer complementary information about "recruitability" of EF. Objectives. To evaluate, in healthy and hypertensive pregnant women (with and without PE), central arterial parameters in conjunction with "basal and recruitable" EF. Methods. Nonhypertensive (HP) and hypertensive pregnant women (gestational hypertension, GH; preeclampsia, PE) were included. Aortic blood pressure (BP), wave reflection parameters (AIx@75), aortic pulse wave velocity (PWVcf) and PWVcr, and brachial and common carotid stiffness and intima-media thickness were measured. Brachial FMD and L-FMC and hyperemic-related change in PWVcr were measured. Results. Aortic BP and AIx@75 were elevated in PE. PE showed stiffer elastic but not muscular arteries. After cuff deflation, PWVcr decreased in HP, while GH showed a blunted PWVcr response and PE showed a tendency to increase. Maximal FMD and L-FMC were observed in HP followed by GH; PE did not reach significant arterial constriction. Conclusion. Aortic BP and wave reflections as well as elastic arteries stiffness are increased in PE. PE showed both "resting and recruitable" endothelial dysfunctions.

The increase of arterial stiffness has been to have a significant impact on predicting mortality in end-stage renal disease patients. Pulse wave velocity (PWV) is a noninvasive, reliable parameter of regional arterial stiffness that integrates the vascular geometry and arterial wall intrinsic elasticity and is capable of predicting cardiovascular mortality in this patient population. Nevertheless, reports on PWV in dialyzed patients are contradictory and sometimes inconsistent: some reports claim the arterial wall stiffness increases (i.e., PWV increase), others claim that it is reduced, and some even state that it augments in the aorta while it simultaneously decreases in the brachial artery pathway. The purpose of this study was to analyze the literature in which longitudinal or transversal studies were performed in hemodialysis and/or peritoneal dialysis patients, in order to characterize arterial stiffness and the responsiveness to renal replacement therapy.

Introduction. Flow-mediated dilation (FMD), low flow-mediated constriction (L-FMC), and reactive hyperemia-related changes in carotid-to-radial pulse wave velocity (ΔPWVcr%) could offer complementary information about both "recruitability" and "resting" endothelial function (EF). Carotid-to-femoral pulse wave velocity (PWVcf) and pulse wave analysis-derived parameters (i.e., AIx@75) are the gold standard methods for noninvasive evaluation of aortic stiffness and central hemodynamics. If healthy pregnancy is associated with both changes in resting and recruitable EF, as well as in several arterial parameters, it remains unknown and/or controversial. Objectives. To simultaneously and noninvasively assess in healthy pregnant (HP) and nonpregnant (NP) women central parameters in conjunction with "basal and recruitable" EF, employing new complementary approaches. Methods. HP (n = 11, 34.2 ± 3.3 weeks of gestation) and age- and cardiovascular risk factors-matched NP (n = 22) were included. Aortic blood pressure (BP), AIx@75, PWVcf, common carotid stiffness, and intima-media thickness, as well as FMD, L-FMC, and ΔPWVcr %, were measured. Results. Aortic BP, stiffness, and AIx@75 were reduced in HP. ΔPWVcr% and FMD were enhanced in HP in comparison to NP. No differences were found in L-FMC between groups. Conclusion. HP is associated with reduced aortic stiffness, central BP, wave reflections, and enhanced recruitable, but not resting, EF.

Background: Cardiac resynchronization therapy (CRT) has benefits on left ventricle (LV) performance, but its mid-term effects on LV load and LV-arterial coupling are unknown., Aims: To evaluate CRT mid-term effects on LV-arterial coupling, arterial load and its determinants, and the association between CRT-dependent aortic haemodynamic changes and the arterial biomechanics., Methods and Results: Cardiac and aortic echographies were done in 25 patients (age: 61 ± 12 years; 14 men; New York Heart Association functional classes III-IV; LV ejection fraction = 28 ± 7%, QRS = 139 ± 20 ms) before and after (23 ± 12 days) CRT. Standard structural and functional parameters and dyssynchrony indices were evaluated. Ascending aorta flow and diameter waveforms were measured. Central pressure was derived using a transfer function and the diameter calibration method. Calculus: arterial elastance (EA); aortic impedance (Zc) and distensibility (AD); systemic resistances (SVR), total compliance (CT); global reflection coefficient; LV end-systolic elastance (EES); and LV-arterial coupling (EA/EES). After CRT EA diminished (-30%;P = 0.001), EES increased (29%; P = 0.001) and EA/EES improved (pre-CRT: 2.9 ± 0.9, post-CRT: 1.6 ± 0.7; P = 0.001). Arterial elastance changes were associated with changes in arterial properties. Cardiac resynchronization therapy was associated with pressure-independent increase in mean aortic diameter (pre-CRT: 30.0 ± 4.0 mm, post-CRT: 33.0 ± 5.1 mm; P = 0.005) and distensibility (pre-CRT: 3.8 ± 2.6 × 10(-3)mmHg(-1), post-CRT: 6.4 ± 2.5 × 10(-3) mmHg(-1); P = 0.002), and Zc reduction (pre-CRT: 3.5 ± 1.8 × 10(-2)mmHg.s/mL, post-CRT:1.9 ± 0.8 × 10(-2) mmHg.s/mL; P = 0.001) and SVR (pre-CRT:1.7 ± 0.4 mmHg.s/mL, post-CRT:1.0 ± 0.3 mmHg.s/mL; P = 0.001). Changes in EA determinants were associated with changes in aortic flow., Conclusion: Early after CRT central and peripheral arterial biomechanics improved, determining a pressure-independent increase in aortic diameter and a reduction in arterial load. Left ventricular systolic performance and LV-arterial coupling were enhanced. Arterial biomechanical changes were associated with aortic flow changes.

Purpose. To evaluate in chronically haemodialysed patients (CHPs), if: (1) the vascular access (VA) position (upper arm or forearm) is associated with differential changes in upper limb arterial stiffness; (2) differences in arterial stiffness exist between genders associated with the VA; (3) the vascular substitute (VS) of choice, in biomechanical terms, depends on the previous VA location and CHP gender. Methods. 38 CHPs (18 males; VA in upper arm: 18) were studied. Left and right carotid-brachial pulse wave velocity (PWV(c-b)) was measured. In in vitro studies, PWV was obtained in ePTFE prostheses and in several arterial and venous homografts obtained from donors. The biomechanical mismatch (BM) between CHP native vessel (NV) and VS was calculated. Results/Conclusions. PWV(c-b) in upper limbs with VA was lower than in the intact contralateral limbs (P < 0.05), and differences were higher (P < 0.05) when the VA was performed in the upper arm. Differences between PWV(c-b) in upper limbs with VA (in the upper arm) with respect to intact upper limbs were higher (P < 0.05) in males. Independently of the region in which the VA was performed, the homograft that ensured the minimal BM was the brachial artery. The BM was highly dependent on gender and the location in the upper limb in which the VA was performed.

Carotid-to-radial pulse wave velocity (PWV(cr)) has been proposed to evaluate endothelial function. However, the measurement of PWV(cr) is not without limitations. A new simple approach could have wide application. Stiffness index (SI) is obtained by analysis of the peripheral pulse wave and gives reproducible information about stiffness of large arteries. This study assessed the effects of hyperemia on SI and compared it with PWV(cr) in 14 healthy subjects. Both were measured at rest and during 8 minutes after ischemia. SI temporal course was determined. At 1 minute, SI and PWV(cr) decreased (5.58 ± 0.24 to 5.34 ± 0.23 m/s, P < 0.05; 7.8 ± 1.0 to 7.2 ± 0.9 m/s; P < 0.05, resp.). SI was positively related to PWV(cr) in baseline (r = 0.62 , P < 0.05), at 1 minute (r = 0.79, P < 0.05), and during the whole experimental session (r = 0.52, P < 0.05). Conclusion. Hyperemia significantly decreases SI in healthy subjects. SI was related to PWV(cr) and could be used to facilitate the evaluation of hyperemia-related changes in arterial stiffness.

Carotid-femoral pulse wave velocity (PWV) has emerged as the gold standard for non-invasive evaluation of aortic stiffness; absence of standardized methodologies of study and lack of normal and reference values have limited a wider clinical implementation. This work was carried out in a Uruguayan (South American) population in order to characterize normal, reference, and threshold levels of PWV considering normal age-related changes in PWV and the prevailing blood pressure level during the study. A conservative approach was used, and we excluded symptomatic subjects; subjects with history of cardiovascular (CV) disease, diabetes mellitus or renal failure; subjects with traditional CV risk factors (other than age and gender); asymptomatic subjects with atherosclerotic plaques in carotid arteries; patients taking anti-hypertensives or lipid-lowering medications. The included subjects (n = 429) were categorized according to the age decade and the blood pressure levels (at study time). All subjects represented the "reference population"; the group of subjects with optimal/normal blood pressures levels at study time represented the "normal population." Results. Normal and reference PWV levels were obtained. Differences in PWV levels and aging-associated changes were obtained. The obtained data could be used to define vascular aging and abnormal or disease-related arterial changes.

This work was carried out in a Uruguayan (South American) population to characterize aging-associated physiological arterial changes. Parameters markers of subclinical atherosclerosis and that associate age-related changes were evaluated in healthy people. A conservative approach was used and people with nonphysiological and pathological conditions were excluded. Then, we excluded subjects with (a) cardiovascular (CV) symptoms, (b) CV disease, (c) diabetes mellitus or renal failure, and (d) traditional CV risk factors (other than age and gender). Subjects (n = 388) were submitted to non-invasive vascular studies (gold-standard techniques), to evaluate (1) common (CCA), internal, and external carotid plaque prevalence, (2) CCA intima-media thickness and diameter, (3) CCA stiffness (percentual pulsatility, compliance, distensibility, and stiffness index), (4) aortic stiffness (carotid-femoral pulse wave velocity), and (5) peripheral and central pressure wave-derived parameters. Age groups: ≤20, 21-30, 31-40, 41-50, 51-60, 61-70, and 71-80 years old. Age-related structural and functional vascular parameters profiles were obtained and analyzed considering data from other populations. The work has the strength of being the first, in Latin America, that uses an integrative approach to characterize vascular aging-related changes. Data could be used to define vascular aging and abnormal or disease-related changes.

Background: The aims were to characterize in muscular arteries (a) the passive and active effects of the adventitia on vessel biomechanical properties and conduit function (CF), and (b) potential differences between the adventitial role in elastic and muscular arteries., Methods and Results: Ovine femoral arteries were studied in vivo and in vitro (reduced smooth muscle-tone) in a circulation mock-up during hemodynamic conditions similar to those found in vivo. Pressure and diameter were assessed before and after removing the adventitia. The arterial compliance, distensibility, stiffness beta-index and CF were quantified. Results were compared with those obtained in brachiocephalic trunks. In vivo, after removing the adventitia there was a nonsignificant diameter reduction and an increase in stiffness (P<0.05). The CF decreased in the early recordings (P<0.02). In vitro, there were no biomechanical changes but vascular dilatation after the adventitia removal. Biomechanical changes associated with the adventitia removal were higher in muscular arteries, whereas diameter changes were major in elastic vessels., Conclusions: After removing the adventitia, (a) the arterial stiffness and CF were modified in vivo only, suggesting the changes could be ascribed to variations in smooth muscle tone, and (b) changes in elastic and muscular arteries were quantitatively different.

Introduction and Objectives: The structural and functional changes observed in the left ventricle in professional soccer players could cause alterations in ventricular rotation (Rv) and ventricular torsion (Tv). Our aim was to characterize the changes in Tv that occur in professional soccer players., Methods: In total, 17 professional soccer players and 10 healthy volunteers who had not undergone training (control subjects) were investigated by M-mode, B-mode and Doppler echocardiography. Left ventricular systolic and diastolic functional and structural parameters were measured. Basal and apical Rv, and Tv were determined using specially developed software (EchoPAC, GE Medical Systems). In addition, Tv was characterized in the time domain., Results: In all subjects, left ventricular structural and functional parameters were within the normal ranges. Both left ventricular ejection fraction and shortening were greater in soccer players (P< .05). The magnitude of apical and basal Rv and the magnitude and velocity of Tv were all lower in soccer players (P< .05). In soccer players, there were negative correlations between the maximum Tv achieved and left ventricular shortening and ejection fraction (P< .05)., Conclusions: The magnitude and velocity of Tv were lower in soccer players. A reduction in Tv might take place under certain physiological conditions and could represent an adaptive response that contributes to increased ventricular efficiency.

Introduction and Objectives: The incidence of cardiovascular events is related to the sleep-wakefulness cycle. In particular, the magnitude and speed of the changes in hemodynamic variables that occur during transitions between wakefulness and sleep and between sleep and wakefulness are regarded as factors that either predict or determine target organ damage and cardiovascular risk. Although increased arterial stiffness (AS) is associated with the development of cardiovascular abnormalities, it is not known whether there exist any changes in AS that are associated with circadian variations in the incidence of cardiovascular events. The aims of this study were to assess AS in healthy subjects over a 24-hour period, to characterize any differences that occur between sleep and wakefulness, and to investigate any changes in AS that occur during the transition from wakefulness to sleep or from sleep to wakefulness., Methods: Twenty healthy volunteers with a dipper circadian blood pressure pattern underwent 24-hour ambulatory monitoring of blood pressure, heart rate and AS. In practice, AS was determined using the aorta-brachial pulse transit time and fractional pulsatility indices. Myocardial oxygen consumption was quantified using the double product (DP). An average was calculated for all variables for periods of sleep (23:00 to 06:00) and wakefulness (8:00 to 21:00) and for transitions from wakefulness to sleep (20:00 vs. 02:00) and from sleep to wakefulness (06:00 vs. 10:00 hours)., Results: In complete contrast to DP, AS was greater during sleep than wakefulness (P< .05). Moreover, the changes in AS that occurred during transitions from wakefulness to sleep and from sleep to wakefulness were the opposite of those observed in DP (P< .05)., Conclusions: Arterial stiffness was greater during sleep than wakefulness, increased during the transition from wakefulness to sleep, and decreased during the transition from sleep to wakefulness.

Introduction and Objectives: Ventricular dynamic afterload depends on arterial viscoelastic and geometric properties. Vasoactive factors produced in the adventitia modulate arterial tone. However, it is still not known whether the adventitia is involved in determining the magnitude of the dynamic afterload. The aim of this study was to investigate the role played by the adventitia, via smooth muscle-dependent mechanisms, in determining dynamic afterload., Methods: The diameter, pressure and flow in brachiocephalic trunks from sheep were measured before and after removal of the adventitia, both in vivo with muscular reactivity preserved (n=8) and in vitro with muscular reactivity abolished (n=8). All studies were performed under similar hemodynamic conditions. Dynamic afterload was determined from elastic and viscous arterial responses, elastic and viscous work, arterial characteristic impedance, and pulse wave velocity. Comparison of in vivo and in vitro findings enabled smooth muscle-dependent changes to be evaluated., Results: Only in vivo, did removal of the adventitia lead to a reduction in vessel diameter (17.32 [2.02] vs 15.46 [1.28] mm) and to increases in elastic (7.21 [1.39] vs 15.59 [3.00] x 10(6) dyn.cm(-2)) and viscous (5.16 [2.04] vs 9.87 [2.00] x 10(5) dyn.s.cm(-2)) arterial responses, elastic (6.15 [1.08] vs 9.20 [0.76] x 10(-2) J/m2) and viscous work (11.61 [2.25] vs 15.20 [2.37] x 10(-3) J/m2), impedance (223.97 [136.11] vs 396.33 [182.27] dyn x s x cm(-3)), and pulse wave velocity (397.70 [31.21] vs 598.78 [28.04] cm.s(-1)) (P<.05). The reduction in diameter and the increases in elastic and viscous responses are evidence of muscular activation., Conclusions: The adventitia may contribute to the control of ventricular dynamic afterload by means of mechanisms dependent on muscular tone.

Introduction and Objectives: It is not yet known whether cryopreservation enables vessels to retain their viscoelastic properties or whether cryopreserved homografts are biomechanically more like native arteries than currently used vascular prostheses. The study objectives were: a) to determine whether our cryopreservation methodology enables arterial and venous homografts to retain their viscoelastic and functional properties; and b) to assess similarities between patients' femoral arteries, homografts, and other vascular prostheses in common use., Methods: The pressure and the diameter and parietal thickness of 15 muscular (femoral) arteries were measured in patients using tonometry and echography, both noninvasive techniques. In addition, the pressure in and diameter and parietal thickness of 15 fresh and 15 cryopreserved human muscular (femoral) artery segments, saphenous veins, and 15 expanded polytetrafluoroethylene (ePTFE) vascular prostheses were measured in vitro under hemodynamic conditions similar to those in patients. A Kelvin-Voigt model of the segment wall was used to derive elastic (Epd, mm Hg/mm) and viscous (Vpd, mm Hg x s/mm) pressure-diameter indices, the buffering function (Vpd/Epd), and the conduit function (1/Zc, where Zc is the characteristic impedance). The incremental Young modulus, the pressure-strain elastic modulus, and pulse wave velocity were also calculated., Results: No difference was observed between either the viscoelastic or functional properties of fresh and cryopreserved homografts. Arterial homografts were the most similar to the patient's arteries., Conclusions: Cryopreservation enabled venous and arterial homografts to retain their viscoelastic and functional properties. Of all the grafts investigated, arterial homografts were most similar, both biomechanically and functionally, to the patient's femoral arteries.