Pulse pressure amplification and its determinants

Central-to-peripheral blood pressure amplification: role of the recording site, technology, analysis approach, and calibration scheme in invasive and non-invasive data agreement

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.

Exercise blood pressure and heart rate responses to graded exercise testing in intermediate versus morning chronotypes with obesity

Exaggerated exercise blood pressure (BP) is linked to cardiovascular disease (CVD). Although evening chronotypes have greater CVD risk than morning (Morn) types, it is unknown if exercise BP differs in intermediate (Int) types. Adults with obesity were classified as either Morn [n = 23 (18 females), Morning-Eveningness Questionnaire (MEQ) = 63.96 ± 1.0, 54.74 ± 1.4 yr, 33.7 ± 0.6 kg/m2] or Int [n = 23 (19 females), MEQ = 51.36 ± 1.1, 55.96 ± 1.8 yr, 37.2 ± 1.2 kg/m2] chronotype per MEQ. A graded, incremental treadmill test to maximal aerobic capacity (V̇o2max) was conducted. Systolic (SBP) and diastolic (DBP) blood pressure and mean arterial pressure (MAP), rate pressure product (RPP), heart rate (HR), and rate of perceived intensity (RPE) were determined at baseline, 4 min, 6 min, and maximal stages. HR recovery (HRR; maximum postexercise) was determined at 1 and 2 min postexercise. Preexercise fasted aortic waveforms (applanation tonometry), plasma leptin, nitrate/nitrite (nitric oxide bioavailability), and body composition (dual X-ray, DXA) were also collected. Int had lower V̇o2max and plasma nitrate (both P ≤ 0.02) than Morn. No difference in preexercise BP, aortic waveforms, or body composition were noted between groups, although higher plasma leptin was seen in Int compared with Morn (P = 0.04). Although Int had higher brachial DBP and MAP across exercise stages (both P ≤ 0.05) and higher HR, RPE, and RPP at 6 min of exercise (all P ≤ 0.05), covarying for V̇o2max nullified the BP, but not HR or RPE, difference. HRR was greater in Morn independent of V̇o2max (P = 0.046). Fasted leptin correlated with HR at exercise stage 4 (r = 0.421, P = 0.041) and 6 min (r = 0.593, P = 0.002). This observational study suggests that Int has exaggerated BP and HR responses to exercise compared with Morn, although fitness abolished BP differences.NEW & NOTEWORTHY This study compares blood pressure and heart rate responses with graded, incremental exercise between morning and intermediate chronotype adults with obesity. Herein, blood pressure responses to exercise were elevated in intermediate compared with morning chronotype, although V̇o2max abolished this observation. However, heart rate responses to exercise were higher in intermediate vs. morning chronotypes independent of fitness. Collectively, this exercise hemodynamic response among intermediate chronotype may be related to reduced aerobic fitness, altered nitric oxide metabolism, and/or elevated aortic waveforms.

Agreement between distal and forearm radial arterial pressures in patients undergoing prone spinal surgery: a prospective, self-controlled, observational study

OBJECTIVE

To test agreement and interchangeability between distal (dRA) and forearm radial arterial (RA) pressures (AP) during general anesthesia (GA) for prone spinal surgery.

METHODS

This prospective observational study involved 40 patients scheduled for GA spinal surgery. The right dRA and left forearm RA were cannulated in all patients to continuously measure invasive blood pressures (IBP). We compared the agreement and trending ability of systolic AP (SAP), diastolic AP (DAP), and mean AP (MAP) at each site 15 minutes after tracheal intubation, start of surgery, 30 and 60 minutes after the start of surgery, and after skin suturing.

RESULTS

Paired BP values (n = 184) (37 cases) were analyzed. The bias (standard deviation), limits of agreement, and percentage error were: SAP: 0.19 (3.03), -5.75 to 6.12, and 5.04%; DAP: -0.06 (1.75), -3.50 to 3.38, and 5.10%; and MAP: 0.08 (1.52), -2.90 to 3.05, and 3.54%, respectively. The linear regression coefficients of determination were 0.981, 0.982, and 0.988 for SAPs, DAPs, and MAPs, respectively; four-quadrant plot concordance rates were 95.11%, 92.03%, and 92.66%, respectively.

CONCLUSION

All arterial BPs showed good agreement and trending capabilities for both the dRA and RA. The dRA may be substituted for the RA in IBP monitoring.

The Relationship of Arsenic Exposure with Hypertension and Wide Pulse Pressure: Preliminary Evidence from Coal-Burning Arsenicosis Population in Southwest China

Evidence from epidemiological studies suggests that chronic arsenic exposure may be associated with a higher incidence of hypertension in the population. However, the effect of arsenic exposure on blood pressure remains unexplored in different populations, regions, and regarding arsenic biomarkers. This study investigated 233 arsenicosis patients and 84 participants from a non-arsenic-exposed area to explore the relationship between arsenic exposure and blood pressure and the occurrence of hypertension and wide pulse pressure (WPP) in patients with coal-burning arsenicosis. The results show that arsenic exposure is related to an increased incidence of hypertension and WPP in the arsenicosis population, primarily due to an induced increase in systolic blood pressure (SBP) and pulse pressure (PP) (OR = 1.47, 1.65, all p < 0.05). The dose-effect relationships between monomethylated arsenicals (MMA), trivalent arsenic (As³⁺), hypertension, and WWP were characterized following trend analyses (all p-trend < 0.05) in the coal-burning arsenicosis population. After adjusting for age, gender, body mass index (BMI), smoking, and alcohol usage, compared with low-level exposure, the high level of MMA exposure increases the risk of hypertension by 1.99 times (CI: 1.04-3.80) and the WPP by 2.42 times (CI: 1.23-4.72). Similarly, the high level of As³⁺ exposure increases the hypertension risk by 3.68 times (CI: 1.86-7.30) and the WPP by 3.84 times (CI: 1.93-7.64). Together, the results revealed that urinary MMA and As³⁺ levels are mainly associated with increased SBP and induce a higher incidence of hypertension and WPP. This study provides preliminary population evidence that cardiovascular-related adverse events such as hypertension and WPP ought to be noticed in the coal-burning arsenicosis population.

Factors associated with arterial stiffness assessed by pulse pressure amplification in healthy children and adolescents: a cross-sectional study

BACKGROUND

Increasing evidence suggests that reducing pulse pressure amplification (PPA) plays an important role in pathogenesis and progression of cardiovascular disease. This is a cross-sectional, observational, and analytical study in which we evaluated the associated factors with a greater chance of reducing PPA in 136 healthy children and adolescents aged 8 to 19 years old stratified by gender and age group.

METHODS

Arterial stiffness and vascular and hemodynamic parameters were non-invasively measured using Mobil-O-Graph® (IEM, Stolberg, Germany), a cuff-based oscillometric device. PPA was expressed as the peripheral-to-central pulse pressure ratio (PPp / PPc). Participants with PPA < 1.49 were considered as part of the arterial stiffness group.

RESULTS

In a univariate model, the increase in total vascular resistance, the reflection coefficient and the augmentation pressure were more likely to have arterial stiffness in all groups. The factors most likely to have arterial stiffness (as assessed by the reduction of the PPA) in the multivariate model were increasing age, the reflection coefficient and cardiac index in the total sample, male group and child and adolescent groups. In addition to age in the female group, cardiac output, stroke volume, and AIx@75 were the factors most likely to present arterial stiffness.

CONCLUSIONS

The results show for the first time in children and adolescents that the factors most likely to reduce PPA are related to the reflection wave, which determines aortic pressures and, therefore, left ventricular afterload.

Arterial stiffness and augmentation index are associated with balance function in young adults

OBJECTIVE

Arterial stiffness and pulsatile central hemodynamics have been shown to affect various aspects of physical function, such as exercise capacity, gait speed, and motor control. The aim of this study was to examine the potential association between arterial stiffness and balance function in healthy younger men and women.

METHODS

112 participants (age = 21 ± 4 years, n = 78 women) underwent measures of arterial stiffness, pulsatile central hemodynamics, balance function and physical fitness in this cross-sectional study. Postural sway was measured in triplicate while participants stood on a foam surface with their eyes closed for 20 s. The average total center of pressure path length from the three trials was used for analysis. Measures of vascular function were estimated using an oscillometric blood pressure device while at rest and included pulse wave velocity (PWV), augmentation index (AIx), and pulse pressure amplification. Measures of physical fitness used as covariates in statistical models included handgrip strength determined from a handgrip dynamometer, lower-body flexibility assessed using a sit-and-reach test, estimated maximal aerobic capacity (VO₂max) using heart rate and a step test, and body fat percentage measured from air displacement plethysmography.

RESULTS

The results from linear regression indicated that after considering sex, mean arterial pressure, body fat, estimated VO₂max, handgrip strength, and sit-and-reach, PWV (β = 0.44, p < 0.05) and AIx (β = - 0.25, p < 0.01) were significant predictors of postural sway, explaining 10.2% of the variance.

CONCLUSION

Vascular function is associated with balance function in young adults independent of physical fitness. Increased arterial stiffness may negatively influence balance, while wave reflections may be protective for balance.

Obesity and Body Mass Components Influence Exercise Tolerance and the Course of Hypertension in Perimenopausal Women

The aim of this study was to identify the potential influence of obesity and body mass components on exercise tolerance assessed in cardiopulmonary exercise testing (CPET), biochemical and echocardiographic parameters and factors correlated with oxygen absorption at the anaerobic threshold in hypertensive women with low levels of physical activity in the perimenopausal period. The study comprised 188 hypertensive women divided, based on body mass index (BMI), into an obesity group and a non-obesity group. Women with BMI ≥ 30 kg/m2 had significantly higher parameters of left ventricular diastolic dysfunction in echocardiography, lower total body water (TBC) in percentage assessed by bioimpedance and significantly worse exercise capacity assessed by CPET. In the study group, VO2 AT (mL/kg/min) correlated positively with TBW (r = 0.4, p < 0.0001) and with the ratio of extracellular water to total body water (ECW/TBW) (r = 0.4, p < 0.00001) and negatively with fat (% and kg) (r = −0.4, p < 0.0001 for both). Obesity negatively affects parameters of diastolic left ventricular function, as well as exercise tolerance in CPET in hypertensive females during the perimenopausal period. The oxygen uptake at anaerobic threshold correlates positively with total body water and ECW/TBW and negatively with body fat; this connection is more pronounced in women without obesity. ClinicalTrials.gov Identifier: NCT04802369.

Impaired subendocardial perfusion in patients with metabolic syndrome

BACKGROUND

Metabolic Syndrome (MS) is associated to vascular damage, increased arterial stiffness, and impaired myocardial perfusion. Subendocardial viability ratio (SEVR) is a noninvasive estimation of myocardial workload, oxygen supply, and perfusion. The aim of the study was to describe the relation between arterial stiffness, SEVR, and cardio-metabolic risk factors.

METHODS

A cohort of 55 patients, aged 59.9 ± 10.8 years, was studied; 28 subjects (50.9%) had metabolic syndrome. All patients underwent a clinical evaluation and blood venous sampling, to assess glico-lipid profile. Applanation tonometry was performed, to obtain pulse wave analysis and SEVR values.

RESULTS

In the overall study population, SEVR showed negative associations with mean (r = -0.301; p = 0.026) and systolic (borderline relation, r = -0.257; p = 0.058) arterial pressure. Metabolic syndrome patients presented lower level of SEVR (p = 0.012), even after adjusting for age, sex, and mean arterial pressure (p = 0.040). Subdividing the study population by the number of metabolic syndrome components, SEVR significantly decreased as the number of Metabolic Syndrome components increased (p for trend 0.005). In a logistic backward regression analysis, both metabolic syndrome and mean arterial pressure resulted significant predictors of SEVR, accounting for 18% of variance.

CONCLUSION

The reduced SEVR in metabolic syndrome patients could be an important pathophysiological determinant of the increased cardiovascular risk.

Daily 100% watermelon juice consumption and vascular function among postmenopausal women: A randomized controlled trial

BACKGROUND AND AIMS

Watermelon juice is a rich food source of cardioprotective compounds such as arginine, citrulline, and lycopene. Preventative interventions are warranted as risk of cardiovascular disease increases among women after menopause, and age alone is an independent risk factor for vascular dysfunction. Thus, this study evaluated the effects of 100% watermelon juice on measures of vascular function.

METHODS AND RESULTS

In this randomized, double-blind, placebo-controlled, crossover trial, 21 healthy postmenopausal women were randomized to consume two 360 mL servings of 100% watermelon juice per day or an isocaloric placebo for four weeks. Following a two-week washout period, they consumed the other beverage for an additional four weeks. Before and after each treatment arm, a fasting blood sample was taken for measurement of serum arginine, citrulline, lycopene, glucose, and insulin. Assessments of vascular function included pulse pressure, pulse wave velocity, 24-h ambulatory blood pressure, and flow-mediated dilation. General linear mixed models with intent-to-treat analyses were used to examine the effects of the intervention. Despite a significant treatment effect for circulating lycopene (p = 0.002), no changes in arginine, citrulline, or any vascular measures were observed. Although the juice intervention resulted in a slight but significant increase in fasting serum glucose (p = 0.001), changes in glucose homeostasis were not clinically significant.

CONCLUSION

In contrast to findings from previous studies in younger adults and those with pre-existing hypertension, measures of vascular function in this cohort of healthy postmenopausal women were not impacted by supplemental watermelon juice. CLINICALTRIALS.

GOV IDENTIFIER

NCT03626168.

The impact of heart rate on pulse wave velocity: an in-silico evaluation

BACKGROUND

Clinical and experimental evidence regarding the influence of heart rate (HR) on arterial stiffness and its surrogate marker carotid-to-femoral pulse wave velocity (cf-PWV) is conflicting. We aimed to evaluate the effect of HR on cf-PWV measurement under controlled haemodynamic conditions and especially with respect to blood pressure (BP) that is a strong determinant of arterial stiffness.

METHOD

Fifty-nine simulated cases were created using a previously validated in-silico model. For each case, cf-PWV was measured at five HR values, 60, 70, 80, 90, 100 bpm. With increasing HR, we assessed cf-PWV under two scenarios: with BP free to vary in response to HR increase, and with aortic DBP (aoDBP) fixed to its baseline value at 60 bpm, by modifying total peripheral resistance accordingly. Further, we quantified the importance of arterial compliance (C) on cf-PWV changes caused by increasing HR.

RESULTS

When BP was left free to vary with HR, a significant HR-effect on cf-PWV (0.66 ± 0.24 m/s per 10 bpm, P < 0.001) was observed. This effect was reduced to 0.21 ± 0.14 m/s per 10 bpm (P = 0.048) when aoDBP was maintained fixed with increasing HR. The HR-effect on the BP-corrected cf-PWV was higher in the case of low C = 0.8 ± 0.3 ml/mmHg (0.26 ± 0.15 m/s per 10 bpm, P = 0.014) than the case of higher C = 1.7 ± 0.5 ml/mmHg (0.16 ± 0.07 m/s per 10 bpm, P = 0.045).

CONCLUSION

Our findings demonstrated that relatively small HR changes may only slightly affect the cf-PWV. Nevertheless, in cases wherein HR might vary at a greater extent, a more clinically significant impact on cf-PWV should be considered.

Association Between Central-Peripheral Blood Pressure Amplification and Structural and Functional Cardiac Properties in Children, Adolescents, and Adults: Impact of the Amplification Parameter, Recording System and Calibration Scheme

INTRODUCTION

Systolic blood pressure (SBPA) and pulse pressure amplification (PPA) were quantified using different methodological and calibration approaches to analyze (1) the association and agreement between different SBPA and PPA parameters and (2) the association between these SBPA and PPA parameters and left ventricle (LV) and atrium (LA) structural and functional characteristics.

METHODS

In 269 healthy subjects, LV and LA parameters were echocardiography-derived. SBPA and PPA parameters were quantified using: (1) different equations (n = 9), (2) methodological approaches (n = 3): brachial sub-diastolic (Mobil-O-Graph®) and supra-systolic oscillometry (Arteriograph®) and aortic diameter waveform re-calibration (RCD; ultrasonography), and (3) using three different calibration schemes: systo-diastolic (SD), calculated mean (CM) and oscillometric mean (OscM).

RESULTS

SBPA and PPA parameters obtained with different equations, techniques, and calibration schemes show a highly variable association level (negative, non-significant, and/or positive) among them. The association between SBPA and PPA with cardiac parameters were highly variable (negative, non-significant, or positive associations). Differences in BPA parameter data between approaches were more sensitive to the calibration method than to the device used. Both, SBPA and PPA obtained with brachial sub-diastolic technique and calibrated to CM or OscM showed higher levels of association with LV and LA structural characteristics.

CONCLUSIONS

Our data show that many of the parameters that assume to quantify the same phenomenon of BPA are not related to each other in the different age groups. Both, SBPA and PPA obtained with brachial sub-diastolic technique and calibrated to CM or OscM showed higher levels of association with LV and LA structural characteristics.

Estimating Central Pulse Pressure From Blood Flow by Identifying the Main Physical Determinants of Pulse Pressure Amplification

Several studies suggest that central (aortic) blood pressure (cBP) is a better marker of cardiovascular disease risk than peripheral blood pressure (pBP). The morphology of the pBP wave, usually assessed non-invasively in the arm, differs significantly from the cBP wave, whose direct measurement is highly invasive. In particular, pulse pressure, PP (the amplitude of the pressure wave), increases from central to peripheral arteries, leading to the so-called pulse pressure amplification (ΔPP). The main purpose of this study was to develop a methodology for estimating central PP (cPP) from non-invasive measurements of aortic flow and peripheral PP. Our novel approach is based on a comprehensive understanding of the main cardiovascular properties that determine ΔPP along the aortic-brachial arterial path, namely brachial flow wave morphology in late systole, and vessel radius and distance along this arterial path. This understanding was achieved by using a blood flow model which allows for workable analytical solutions in the frequency domain that can be decoupled and simplified for each arterial segment. Results show the ability of our methodology to (i) capture changes in cPP and ΔPP produced by variations in cardiovascular properties and (ii) estimate cPP with mean differences smaller than 3.3 ± 2.8 mmHg on in silico data for different age groups (25-75 years old) and 5.1 ± 6.9 mmHg on in vivo data for normotensive and hypertensive subjects. Our approach could improve cardiovascular function assessment in clinical cohorts for which aortic flow wave data is available.

Conduit arterial wave reflection promotes pressure transmission but impedes hydraulic energy transmission to the microvasculature

With aging, a reduction in the stiffness gradient between elastic and muscular arteries is thought to reduce wave reflection in conduit arteries, leading to increased pulsatile pressure transmission into the microvasculature. This assumes that wave reflection limits pressure transmission in arteries. However, using a computational model, we showed that wave reflection promotes pulsatile pressure transmission, although it does limit hydraulic energy transmission. Increased microvascular pulse pressure with aging is instead related to decreasing arterial compliance.

The Effects of Mat Pilates Training on Vascular Function and Body Fatness in Obese Young Women With Elevated Blood Pressure

BACKGROUND

Effective nonpharmacological interventions targeting the enhancement of vascular function and decline of body fatness (BF) in obese individuals are indispensable for the prevention of hypertension and cardiovascular events in young adults. Mat Pilates training (MPT) has gained significant popularity worldwide, yet its effects on vascular function and body composition are understudied. We examined the effects of MPT on vascular function and BF in young obese women with elevated blood pressure (BP).

METHODS

Twenty-eight young obese women with elevated BP were randomized to an MPT (n = 14) or a nonexercising control (CON, n = 14) group for 12 weeks. Systemic arterial stiffness (brachial-ankle pulse wave velocity (baPWV)), brachial and aortic BP, wave reflection (augmentation index (AIx)), plasma nitric oxide (NO) levels, and BF percentage (BF%) were assessed before and after 12 weeks.

RESULTS

MPT significantly reduced (P ˂ 0.05) baPWV (-0.7 ± 0.2 m/s), AIx (-4 ± 1%), brachial systolic BP (-5 ± 1 mm Hg), aortic systolic BP (-6 ± 1 mm Hg), and BF% (-2 ± 1%), while significantly increasing plasma NO (6 ± 2 µM) (P ˂ 0.05) compared with CON. MPT improved systemic arterial stiffness, aortic BP, wave reflection, circulating plasma NO, and BF% in young obese women with elevated BP.

CONCLUSIONS

MPT may be an effective intervention for the improvement of vascular function and BF in young obese women with elevated BP, a population at risk for hypertension and early vascular complications.

CLINICAL TRIALS REGISTRATION

Trial Number NCT03907384.

Wave reflections and systemic vascular resistance are stronger determinants of pulse pressure amplification than aortic stiffness in drug-naïve hypertensives

Background: Aortic-to-brachial pulse pressure (PP) amplification is a novel biomarker that prognosticates the cardiovascular risk above and beyond central aortic and brachial blood pressure. This phenomenon is modulated by left ventricular contractility and chronotrophy, large-artery stiffness and reflecting properties of microcirculation. However, the relative importance of these parameters as hemodynamic determinant of PP amplification remains elusive.Methods: A total of 88 consecutive drug-naïve hypertensives underwent a non-invasive assessment of central and peripheral hemodynamics via impedance cardiography and pulse wave analysis. Participants were classified into tertiles according to the magnitude of PP amplification. Hemodynamic determinants of low PP amplification were explored in univariate and multivariate regression analysis.Results: Compared with the high tertile, patients within the low PP amplification tertile were older and more commonly female and had lower height, weight and heart rate. Augmentation index (AIx) and systemic vascular resistance index (SVRI) were higher among patients within the low PP amplification tertile, whereas aortic pulse wave velocity (PWV) did not differ among groups. In multivariate analysis, higher AIx (OR: 1.27; 95% CI: 1.09-1.48) and higher SVRI were independently associated with higher odds for low PP amplification, whereas higher heart rate was the only parameter related to lower odds for low PP amplification (OR: 0.84; 95% CI: 0.71-0.99).Conclusion: This study shows that among newly-diagnosed drug-naïve hypertensives, elevated wave reflections and systemic vascular resistance are stronger determinants of PP amplification than aortic stiffness.

The association of smoothness index of central blood pressure with ambulatory carotid femoral pulse wave velocity after 20-week treatment with losartan in combination with amlodipine versus hydrochlorothiazide

Supplemental Digital Content is available in the text

The aim of this study was to identify associations between the smoothness index of central SBP (CSBP) and changes of ambulatory carotid femoral pulse wave velocity in response to 20-week treatments with losartan and amlodipine vs. losartan and hydrochlorthiazide combinations.

Electrocardiographic left ventricular hypertrophy in relation to peripheral and central blood pressure indices in a Nigerian population

Purpose: Previous studies that addressed whether left ventricular hypertrophy is more closely associated with central than peripheral blood pressure (BP) have been inconsistent. Radial artery wave generated by applanation tonometry and calibrated with brachial BP in 162 adult Nigerians were analysed by using generalized transfer function to derive central BP.Materials and methods: We compared the associations of ECG voltages and left ventricular hypertrophy (ECG-LVH) as continuous and binary variables respectively with central and brachial BP indices.Results: In a multivariable adjusted analysis, 1 standard deviation (SD) increase in brachial systolic, diastolic, pulse and mean arterial pressures increased the Sokolow-Lyon QRS voltage by 0.34 (CI, 0.21-0.48; p < 0.0001), 0.21 (CI, 0.07-0.36; p < 0.05); 0.22 (CI, 0.9-0.34; p < 0.001) and 0.29 (CI, 0.14-0.43) similar to (p > 0.05) corresponding Sokolow-Lyon QRS increase of 0.26 (0.12-0.40, p < 0.001); 0.14 (0.00-0.28, p < 0.05); 0.24 (0.11-0.39; p < 0.001) and 0.19 (0.05-0.34, p < 0.05) respectively observed for 1 SD increment in central pressures. The odds ratio (OR) relating ECG-LVH to 1 SD increase in brachial systolic, pulse, and mean arterial pressures were 2.62 (CI, 1.49-4.65, p < 0.001); 1.88 (CI, 1.19-2.95, p < 0.01) and 2.16 (CI, 1.22-3.82, p < 0.01) was similar to (p > 0.05) corresponding OR of 2.41 (1.33-4.36, p < 0.01); 2.04 (1.23-3.37, p < 0.01); 2.00 (1.11-3.63, p < 0.001) observed for I SD increment in central pressures.Conclusion: Central and peripheral BP are similarly associated with Sokolow-Lyon ECG voltage and hypertrophy.

Feasibility of Fingertip Oscillometric Blood Pressure Measurement: Model-Based Analysis and Experimental Validation

The most commonly used oscillometric upper-arm (UA) blood pressure (BP) monitors are not convenient enough for ambulatory BP monitoring, given the large size of the arm cuff and the compression of UA during the measurement. Finger-worn oscillometric BP devices featuring miniaturized finger cuff have been developed and researched as an alternative solution to the UA-based measurement, yet the reliability of the finger-based measurement is still questioned. To investigate the feasibility of oscillometric BP measurements at the finger position, we performed model-based analysis and experimental validation to explore the underlying issues associated with extending the cuff-based oscillometric approach from UA to other alternative sites. The simulation results revealed that a larger bone-to-tissue volume ratio produced a lower pressure transmission efficiency, which can account for the inter-site measurement discrepancies of mean blood pressure (MBP). We also experimentally compared the oscillometric MBP measurements at UA, middle forearm, wrist, finger proximal phalanx, and finger distal phalanx (FD) of 20 young adults, and each position was matched with a cuff of appropriate size and kept at the same height with the heart. The experimental results demonstrated that FD could be a superior alternative position for oscillometric BP measurement, as it requires the smallest cuff size while providing the most consistent MBP with the UA. Our analysis also suggested that further study is demanded to identify the appropriate oscillometric algorithm for reliable systolic blood pressure and diastolic blood pressure measurements at FD.

Associations Between Obstructive Sleep Apnea and Measures of Arterial Stiffness

STUDY OBJECTIVES

The aim of this study was to determine whether severity measures of obstructive sleep apnea (OSA) are associated with arterial stiffness and central blood pressure (two important cardiovascular risk factors) in a large group of patients with OSA.

METHODS

Baseline data from six studies on OSA in which arterial stiffness and central aortic blood pressure measures were determined using applanation tonometry were pooled. Associations between measures of arterial stiffness (heart rate corrected augmentation index [AI75]), central aortic blood pressure (central systolic pressure [CSP] and heart rate corrected central augmentation pressure [CAP75]) and measures of OSA severity were explored using stepwise regression modelling.

RESULTS

Data from 362 participants (M:F ratio 13:1) with mean (standard deviation) age 49.2 (11.0) years, body mass index 31.9 (5.3) kg/m², apnea-hypopnea index (AHI) 35.7 (20.7) events/h were included in the analyses. The AHI, oxygen desaturation index (ODI3%), and sleep time with SpO₂ < 90% (T90) were all associated with arterial stiffness (AI75), (AHI: adj. β = .069; P = .01; ODI3%: adj. β = .072; P = .01; T90: adj. β = .18; P < .0001) and CAP75 (AHI: adj. β = .030; P = .01; ODI3%: adj. β = .027; P = .02; T90: adj. β = .080; P < .0001). AHI was also associated with CSP (AHI: adj. β = .11; P = .002).

CONCLUSIONS

OSA severity was significantly associated with augmentation index and CAP75 although the relationships were not strong.

Cardiac amyloidosis is associated with increased aortic stiffness

OBJECTIVE

Cardiac amyloidosis (CA) is as an infiltrative disorder primarily caused by extracellular tissue deposition of amyloid fibrils in the myocardial interstitium. The current study was designed to test whether alterations in ascending aortic elastic properties could be detected by echocardiography in CA patients, and to compare their results to controls.

PATIENTS AND METHODS

We included 19 CA patients from which CA proved to be AL amyloidosis in 17 cases and transthyretin (TTR) amyloidosis in 2 cases. Their results were compared to 20 age-, gender-, and risk factor-matched controls.

RESULTS

There was significantly greater interventricular septum and left ventricular (LV) posterior wall thickness, lower LV ejection fraction and greater E/A in CA patients than in controls, suggesting systolic, and diastolic dysfunction. CA patients also showed significantly reduced aortic strain and pulsatile change in aortic diameter, and increased aortic stiffness index.

CONCLUSION

These results suggest increased aortic stiffness in CA patients.

Central blood pressure and pulse wave amplification across the spectrum of peripheral blood pressure in overweight and obese youth

OBJECTIVE

To identify vascular phenotypes across blood pressure (BP) conditions in overweight and obese youths, by assessing office BP (oBP), and central BP (cBP), and pulse pressure (PP) amplification. Whether or not 24-h ambulatory BP monitoring (ABPM) and pulse wave velocity (PWV) add insight to the issue has also been examined.

METHODS

White youths of both sexes with overweight or obesity and of European origin, ranging from 8 to 18 years of age, were included. oBP, cBP, PWV, and 24-h ABPM were measured. oBP conditions and 'white-coat' hypertension were defined as recommend by European Society Hypertension Guidelines in Children and Adolescents. Patients were divided into subgroups of 'normal' or 'high' according to cBP and PP ratio.

RESULTS

A total of 593 patients (mean age, 12.2 ± 2.3 years; 275 women) were included in the study. The largest differences between office SBP and central SBP correspond to the isolated systolic hypertension (ISH) group, in which only 25% of patients have high cBP, in contrast to 50% of the systo-diastolic hypertension (SDH) group. Two patterns emerged based on cBP and PP ratio - while the highest cBP was among the SDH, the highest PP amplitude was in the ISH group. Ninety percent of the SDH were confirmed with 24-h ABPM, in contrast to 75% of the ISH, who were white-coat hypertensive. PWV showed a progressive increment across the groups from normotension to SDH. Significant differences were observed only when compared with the normotensive, but not among all other groups.

CONCLUSION

In overweight and obese hypertensive patients, ISH is prevalent, posing a challenge for the clinician of whether these may therefore be diagnosed and managed as hypertensive patients. Until prospective studies can give more knowledge, 24-h ABPM can offer information for making clinical decisions.

Factors associated with the reduction of albumin excretion in diabetic hypertensive patients: differential effect of manidipine versus amlodipine

AIMS

In AMANDHA trial, the addition of manidipine, but not amlodipine, in diabetic patients with uncontrolled hypertension, microalbuminuria and preserved renal function resulted in a large decrease of urinary albumin excretion (UAE) despite similar blood pressure (BP) reductions. Factors associated with the reduction of UAE were analyzed.

METHODS

For this purpose, a multivariable analysis was performed.

RESULTS

Although after 6 months of treatment, manidipine and amlodipine decreased BP to a similar extent, reductions of UAE were higher with manidipine. The assigned treatment, changes in mean BP, sympathetic tone and glycemic control were associated with changes in UAE.

CONCLUSION

The assigned treatment, changes in mean BP, sympathetic tone and glycemic control were independently associated with changes in UAE. Compared with amlodipine, manidipine reduced UAE to a higher extent, independently of BP reduction.