Association of central and peripheral pulse pressure with intermediate cardiovascular phenotypes

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.

Comparison of Influence of Blood Pressure and Carotid-Femoral Pulse Wave Velocity on Target Organ Damage in Hypertension

Objectives

Assessment of target organ damage (TOD) is an important part of the diagnosis and evaluation of hypertension. Carotid-femoral pulse wave velocity (cf-PWV) is considered to be the gold-standard for noninvasive arterial stiffness assessment. This study aims to analyze the risk of TOD in people with different phenotypes of peripheral blood pressure and cf-PWV.

Methods

The study cohort was recruited from December 2017 to September 2021 at Ruijin Hospital in Shanghai. It was divided into 4 groups according to peripheral blood pressure (pBP) and cf-PWV. TOD was assessed as carotid intima-media thickness (CIMT), chronic kidney disease (CKD), urinary albumin-creatinine ratio (ACR), estimated glomerular filtration rate (eGFR) and left ventricular mass index (LVMI).

Results

A total of 1,257 subjects (mean age 53.13 ± 12.65 years, 64.2% males) was recruited. Age, body mass index (BMI) and fasting blood glucose (FBG), as well as peripheral systolic blood pressure (pSBP), peripheral diastolic blood pressure (pDBP), peripheral pulse pressure (pPP) were significantly different in the four groups (P < 0.01). eGFR, ACR, LVMI and CIMT were significantly different among different groups (P < 0.01). The risk of ACR abnormality was significantly higher in the group with elevated pBP (P = 0.005, OR 2.264, 95%CI 1.277–4.016; and in the group with elevated pBP and cf-PWV (P = 0.003, OR 1.482, 95%CI 1.144–1.920), while left ventricular hypertrophy (LVH) was significantly higher in the group with elevated cf-PWV (P = 0.002, OR 1.868, 95%CI 1.249–2.793).

Conclusion

Different profiles based on the status of PBP and cf-PWV associated with different TOD. Individuals with higher pBP have an increased risk of ACR abnormality, while individuals with only cf-PWV elevated have a higher risk of LVH.

Sex Differences in Longitudinal Determinants of Carotid Intima Medial Thickening With Aging in a Community-Dwelling Population: The Baltimore Longitudinal Study on Aging

Background Common carotid intima medial thickness (IMT) increases with aging. However, the longitudinal association between IMT and other age-associated hemodynamic alterations in men and in women are not fully explored. Methods and Results We analyzed repeated measures of IMT, blood pressure, and carotid-femoral pulse wave velocity over a 20-year period in 1067 men and women of the Baltimore Longitudinal Study on Aging; participants were ages 20 to 92 years at entry and free of overt cardiovascular disease. Linear mixed-effects models were used to calculate the individual rates of change (_Change) of IMT, pulse pressure, mean arterial pressure, and pulse wave velocity, among other covariates. Multivariate regression analysis was used to examine the association of IMT_Change with baseline and rates of change of hemodynamic parameters and cardiovascular risk factors. IMT increased at accelerating rates from 0.02 mm/decade at age 50 years to 0.05 mm/decade at age 80 years greater rates in men than in women. IMT_Change was positively associated with baseline low-density lipoprotein, low-density lipoprotein_Change, and baseline systolic blood pressure and systolic blood pressure_Change, but inversely with baseline diastolic blood pressure and diastolic blood pressure_Change. When blood pressure was expressed as pulse pressure and MAP, IMT_Change was positively associated with baseline pulse pressure and pulse pressure_Change and inversely with baseline mean arterial pressure and mean arterial pressure_Change. In sex-specific analysis, these associations were observed in women, but not in men. Conclusions In summary, our analyses showed that IMT increases at accelerating rates with aging. Age-associated changes in IMT were modulated by concurrent changes of low-density lipoprotein in both sexes, and of pulsatile and mean blood pressure in women but not men.

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.

Relation of blood pressure and organ damage: comparison between feasible, noninvasive central hemodynamic measures and conventional brachial measures

OBJECTIVE

The present cross-sectional study investigated whether central SBP and pulse pressure (PP) measured noninvasively with a novel cuff-based stand-alone monitor are more strongly associated with hypertensive end-organ damage than corresponding brachial measures.

METHODS

We investigated the cross-sectional association of central versus brachial SBP and PP with echocardiographic left ventricular mass index (LVMI), LV hypertrophy (LVH), carotid intima-media thickness (IMT), and increased IMT (IMT ≥ 75th percentile) among 246 participants drawn from the general population (mean age 57.2 years, 55.3% women).

RESULTS

All blood pressure (BP) measures were positively correlated with LVMI and IMT (P < 0.001 for all). Brachial and central SBP correlated equally strongly with LVMI (r = 0.42 versus 0.40, P for difference 0.19) and IMT (r = 0.32 versus 0.33, P = 0.60). However, brachial PP correlated more strongly than central PP with LVMI (r = 0.34 versus 0.27, P = 0.03) and IMT (r = 0.40 versus 0.35, P = 0.04). In multivariable-adjusted logistic models, all four BP measures were significantly associated with LVH and increased IMT (P ≤ 0.03 for all). However, the diagnostic accuracy of logistic regression models that included brachial or central hemodynamic parameters was similar for LVH [area under curve (AUC) for SBP: 0.74 versus 0.76, P = 0.16; AUC for PP: 0.75 versus 0.73, P = 0.35] and IMT (AUC for SBP: 0.61 versus 0.61, P = 0.67; AUC for PP: 0.63 versus 0.61, P = 0.29).

CONCLUSION

Our findings suggest that central SBP and PP measured with a stand-alone noninvasive BP monitor do not improve diagnostic accuracy for end-organ damage over corresponding brachial measures.

Association between the level of serum soluble ST2 and invasively measured aortic pulse pressure in patients undergoing coronary angiography

Despite the well-documented value of ST2 in heart failure and myocardial infarction, the role of ST2 in vascular biology has not yet been well defined. This study was performed to investigate the association between serum soluble ST2 (sST2) and invasively measured aortic pulse pressure (APP). A total of 167 consecutive patients with suspected coronary artery disease (CAD) (65.1 ± 9.8 years; men, 65.9%) referred for invasive coronary angiography was prospectively enrolled. APP was measured at the ascending aorta with a pig-tail catheter, and arterial blood samples for the measurement of sST2 were collected before coronary angiography. Serum sST2 levels were quantified by radioimmunoassay. Most of the patients (73.9%) had significant CAD (stenosis ≥ 50%) on coronary angiography. Patients with higher APP (≥76 mmHg) showed a significantly higher sST2 level compared to those with lower APP (<76 mmHg) (31.7 ± 13.9 ng/mL vs 26.2 ± 10.2 ng/mL, P < .001). In simple correlation analysis, there was a significant positive correlation between sST2 levels and APP (r = 0.413, P < .001). In multiple linear regression analysis, sST2 had an independent association with APP even after controlling for potential confounders (β = 0.331, P < .001). The serum sST2 level may be independently associated with invasively measured APP in patients undergoing coronary angiography. The result of this study gives insight into the role of sST2 in aortic stiffening, and suggests that the sST2 level may be a useful marker of aortic stiffness.

Determinants of pulse pressure amplification in hypertensive and diabetic patients

Hypertensive diabetic patients remain at high cardiovascular risk despite adequate blood pressure and glycemic control. Pulse pressure amplification (PPA) is expressed as the peripheral-to-central PP ratio and provides complementary information for use in assessing cardiovascular risk. The aim of our study was to determine the clinical and biological determinants of PPA in hypertensive and diabetic patients. A cross-sectional study was conducted in 624 patients. Applanation tonometry was used to determine hemodynamic parameters. Age, gender, and the association between hypertension and diabetes were the independent factors of PPA in our population (N = 624). A threshold of 55 years of age was chosen because of its link with menopause in our analysis. Multivariate regression analyses were performed to evaluate the independent determinants of PPA for hypertensive diabetic and hypertensive nondiabetic male and female patients. HbA1c level is the main factor of increased PPA regardless of age and gender (P < 0.05). Mean BP negatively regulates PPA in the overall study: men > 55 years (P = 0.0001) and women > 55 years (P = 0.03). The threshold calculated glomerular filtration rate (cGFR) < 60 mL/min/1.73 m2 was an independent and negative factor of PPA in hypertensive diabetic men regardless of age (P < 0.05) and in women > 55 years (P = 0.04). Mean BP negatively regulates PPA in hypertensive nondiabetic patients (P < 0.04) regardless of age and gender, except in women > 55 years, where cGFR < 60 (P = 0.04) negatively regulates the modulation of PPA. HbA1c and threshold cGFR < 60 have highly significant impacts on PPA in hypertensive diabetic patients, whereas mean BP appears as the main factor of PPA in hypertensive nondiabetic patients.

Association of Haemodynamic Indices of Central and Peripheral Pressure with Subclinical Target Organ Damage

Background

Central aortic pressure has often been shown to be more closely associated with markers of vascular function and incidence of cardiovascular events compared to peripheral pressure. However, the potential clinical use of central aortic or peripheral haemodynamic indices as markers of target organ damage (TOD) has not been fully established.

Methods

We evaluated associations of TOD with central aortic and peripheral haemodynamic indices (central aortic [cPP] and peripheral pulse pressure [pPP], central aortic augmentation index, and central and peripheral waveform factor) in 770 hospital inpatients (age 60 ± 10 years, 473 males) with primary hypertension. TOD was quantified in terms of arterial stiffness as measured by carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (IMT), and urine albumin-to-creatinine ratio (ACR). Subclinical TOD was defined as carotid IMT >0.9 mm, urine ACR >3.5 mg/mmol in females and >2.5 mg/mmol in males and/or cfPWV >12 m/s.

Results

Both cPP and pPP showed significant correlation with cfPWV (r = 0.41 vs. 0.40; p < 0.01), ACR (r = 0.24 vs. 0.27; p < 0.01) and carotid IMT (r = 0.14 vs. 0.15; p < 0.01). Each SD increase in pPP and cPP was associated with increased risk of cfPWV >12 m/s (odds ratio [OR] = 2.7 and 2.9 for pPP and cPP, respectively), ACR >2.5 mg/mmol (OR = 1.2 and 1.4, respectively), and carotid IMT >0.9 mm (OR = 1.46 and 1.53, respectively). Compared to pPP, cPP had higher predictive power for TOD for age ≥60 years (OR = 3.07, p < 0.001).

Conclusions

Although both pPP and cPP show an association with TOD in a hypertensive population, cPP provides additional information beyond pPP associated with TOD in a hypertensive cohort. Central aortic haemodynamic indices as potential biomarkers of subclinical TOD need to be validated by further prospective studies.

Association of arterial stiffness and central hemodynamics with moderately reduced glomerular filtration rate in Chinese middle-aged and elderly community residents: a cross-sectional analysis

Background

Kidney impairment constitutes severe risk for cardiovascular disease, stroke and all-cause mortality, and early identification and prevention of kidney impairment is critical to effective management of prognostic risk in community residents. Previous studies have validated that carotid-femoral pulse wave velocity (cfPWV) is a significant factor associated with chronic kidney disease. However, whether cfPWV is associated with moderately reduced glomerular filtration rate (GFR) remains unclear. This analysis was designed to examine the association of moderately reduced GFR with cfPWV and central pulse pressure (cPP) in Chinese middle-aged and elderly community residents.

Methods

There were 875 community residents enrolled in this analysis, and then cfPWV and cPP were assessed in all participants following the standard procedure.

Results

Entire cohort had a median (range) age of 66 (45–88) years, and 65.4% were women. Both cfPWV and cPP differed significantly between participants with and without moderately reduced GFR (P < 0.05 for all). Logistic regression analyses indicated that cfPWV and cPP had the significant association with moderately reduced GFR (P < 0.05 for all).

Conclusion

This analysis demonstrated the significant association of cfPWV and cPP with moderately reduced GFR in Chinese middle-aged and elderly community residents.

Use of Biomarkers in the Evaluation and Treatment of Hypertensive Patients

The current definition of hypertension is based on blood pressure values, and blood pressure also drives treatment decisions, is the most important treatment monitoring tool and helps estimating risk of hypertension-related organ damage. In an era of precision medicine, additional biomarkers are needed in the diagnosis and management of patients with hypertension. In this review, we outline the areas in which functional, imaging and circulating biomarkers could help in a more individualised definition of hypertension and associated risk. We will cover biomarkers for diagnosis; of pathophysiology and prediction of hypertension; response to treatment, organ damage; and to monitor treatment. A clear focus is on the vasculature, the heart and the kidneys, whereas we see a need to further develop biomarkers of cerebral function in order to diagnose cognition deficits and monitor changes in cognition in the future to support addressing the growing burden of hypertension-associated vascular dementia.

Proteomic-Biostatistic Integrated Approach for Finding the Underlying Molecular Determinants of Hypertension in Human Plasma

Despite advancements in lowering blood pressure, the best approach to lower it remains controversial because of the lack of information on the molecular basis of hypertension. We, therefore, performed plasma proteomics of plasma from patients with hypertension to identify molecular determinants detectable in these subjects but not in controls and vice versa. Plasma samples from hypertensive subjects (cases; n=118) and controls (n=85) from the InGenious HyperCare cohort were used for this study and performed mass spectrometric analysis. Using biostatistical methods, plasma peptides specific for hypertension were identified, and a model was developed using least absolute shrinkage and selection operator logistic regression. The underlying peptides were identified and sequenced off-line using matrix-assisted laser desorption ionization orbitrap mass spectrometry. By comparison of the molecular composition of the plasma samples, 27 molecular determinants were identified differently expressed in cases from controls. Seventy percent of the molecular determinants selected were found to occur less likely in hypertensive patients. In cross-validation, the overall R² was 0.434, and the area under the curve was 0.891 with 95% confidence interval 0.8482 to 0.9349, P<0.0001. The mean values of the cross-validated proteomic score of normotensive and hypertensive patients were found to be -2.007±0.3568 and 3.383±0.2643, respectively, P<0.0001. The molecular determinants were successfully identified, and the proteomic model developed shows an excellent discriminatory ability between hypertensives and normotensives. The identified molecular determinants may be the starting point for further studies to clarify the molecular causes of hypertension.

Prediction of acute coronary syndromes by urinary proteome analysis

Identification of individuals who are at risk of suffering from acute coronary syndromes (ACS) may allow to introduce preventative measures. We aimed to identify ACS-related urinary peptides, that combined as a pattern can be used as prognostic biomarker. Proteomic data of 252 individuals enrolled in four prospective studies from Australia, Europe and North America were analyzed. 126 of these had suffered from ACS within a period of up to 5 years post urine sampling (cases). Proteomic analysis of 84 cases and 84 matched controls resulted in the discovery of 75 ACS-related urinary peptides. Combining these to a peptide pattern, we established a prognostic biomarker named Acute Coronary Syndrome Predictor 75 (ACSP75). ACSP75 demonstrated reasonable prognostic discrimination (c-statistic = 0.664), which was similar to Framingham risk scoring (c-statistics = 0.644) in a validation cohort of 42 cases and 42 controls. However, generating by a composite algorithm named Acute Coronary Syndrome Composite Predictor (ACSCP), combining the biomarker pattern ACSP75 with the previously established urinary proteomic biomarker CAD238 characterizing coronary artery disease as the underlying aetiology, and age as a risk factor, further improved discrimination (c-statistic = 0.751) resulting in an added prognostic value over Framingham risk scoring expressed by an integrated discrimination improvement of 0.273 ± 0.048 (P < 0.0001) and net reclassification improvement of 0.405 ± 0.113 (P = 0.0007). In conclusion, we demonstrate that urinary peptide biomarkers have the potential to predict future ACS events in asymptomatic patients. Further large scale studies are warranted to determine the role of urinary biomarkers in clinical practice.

Comparison of different statistical approaches for urinary peptide biomarker detection in the context of coronary artery disease

Background

When combined with a clinical outcome variable, the size, complexity and nature of mass-spectrometry proteomics data impose great statistical challenges in the discovery of potential disease-associated biomarkers. The purpose of this study was thus to evaluate the effectiveness of different statistical methods applied for urinary proteomic biomarker discovery and different methods of classifier modelling in respect of the diagnosis of coronary artery disease in 197 study subjects and the prognostication of acute coronary syndromes in 368 study subjects.

Results

Computing the discovery sub-cohorts comprising \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\scriptscriptstyle \raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right.} $$\end{document}23 of the study subjects based on the Wilcoxon rank sum test, t-score, cat-score, binary discriminant analysis and random forests provided largely different numbers (ranging from 2 to 398) of potential peptide biomarkers. Moreover, these biomarker patterns showed very little overlap limited to fragments of type I and III collagens as the common denominator. However, these differences in biomarker patterns did mostly not translate into significant differently performing diagnostic or prognostic classifiers modelled by support vector machine, diagonal discriminant analysis, linear discriminant analysis, binary discriminant analysis and random forest. This was even true when different biomarker patterns were combined into master-patterns.

Conclusion

In conclusion, our study revealed a very considerable dependence of peptide biomarker discovery on statistical computing of urinary peptide profiles while the observed diagnostic and/or prognostic reliability of classifiers was widely independent of the modelling approach. This may however be due to the limited statistical power in classifier testing. Nonetheless, our study showed that urinary proteome analysis has the potential to provide valuable biomarkers for coronary artery disease mirroring especially alterations in the extracellular matrix. It further showed that for a comprehensive discovery of biomarkers and thus of pathological information, the results of different statistical methods may best be combined into a master pattern that then can be used for classifier modelling.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-016-1390-1) contains supplementary material, which is available to authorized users.

Pulse pressure amplification and its determinants

BACKGROUND

Pulse pressure (PP) amplification expressed as the peripheral-to-central PP ratio has gained importance in the assessment of cardiovascular phenotypes and cardiovascular risk. The aim of the present study was to assess the relationship between PP amplification, large vessel parameters and peripheral blood pressure (BP) to gain insights into the amplification phenomenon.

METHODS

Peripheral BP, central BP and carotid-femoral pulse wave velocity (cfPWV) were assessed using the OMRON M6, SphygmoCor and Complior devices, respectively, in 741 adults attending the hypertension outpatient clinic. Analysis of covariance, partial correlations and multiple linear regression models were performed to assess the relationship between PP amplification, peripheral BP and cfPWV.

RESULTS

PP amplification was inversely related to BP group. Women showed lower PP amplification than men (1.24 ± 0.18 and 1.35 ± 0.18, respectively, p < 0.001). Age, female gender and mean arterial pressure were inversely associated with PP amplification (p < 0.001), whereas heart rate and body mass index showed positive associations (p < 0.001 and p = 0.049, respectively). cfPWV was a predictor of PP amplification in men but not in women (p = 0.006 and p = 0.424, respectively).

CONCLUSIONS

PP amplification is related to BP: the higher the BP, the lower the PP amplification. Gender, age and body composition have a significant impact on PP amplification.

Association of Central Versus Brachial Blood Pressure With Target-Organ Damage: Systematic Review and Meta-Analysis

Accumulating evidence suggests that central blood pressure (BP) may reflect the hemodynamic stress on target organs more accurately than brachial BP. A systematic review assessing the relationship of central versus brachial BP with preclinical target-organ damage was performed. Meta-analysis of cross-sectional data showed that central compared with brachial systolic BP was more closely associated with (1) left ventricular mass index (12 studies, n=6431; weighted age [SD], 49.9 [13.1] years; 51% hypertensives): pooled correlation coefficients r=0.30; 95% confidence interval (CI), 0.23-0.37 versus r=0.26; 95% CI, 0.19-0.33, respectively; P<0.01 for difference; (2) carotid intima-media thickness (7 studies, n=6136; weighted age, 55.6 [13.2] years; 48% hypertensives): r=0.27; 95% CI, 0.19-0.34 versus r=0.23; 95% CI, 0.16-0.30, respectively; P<0.01 for difference; (3) pulse-wave velocity (14 studies, n=3699; weighted age, 53.9 [13.3] years; 53% hypertensives): r=0.42; 95% CI, 0.37-0.47 versus r=0.39; 95% CI, 0.33-0.45, respectively; P<0.01 for difference. Four studies assessing urine albumin excretion (n=3718; weighted age, 56.4 [5] years; 69% hypertensives) reported similar correlations (P=not significant) with central (r=0.22; 95% CI, 0.14-0.29) and brachial systolic BP (r=0.22; 95% CI, 0.12-0.32). Similar findings were observed for central compared with brachial pulse pressure in terms of relationship with target-organ damage. Metaregression analyses did not reveal any significant effect of age. In conclusion, central compared with brachial BP seems to be more strongly associated with most of the investigated indices of preclinical organ damage.

Relation between exercise central haemodynamic response and resting cardiac structure and function in young healthy men

BACKGROUND

Left ventricular (LV) structure and function are predictors of cardiovascular (CV) morbidity and mortality and are related to resting peripheral haemodynamic load in older adults. The central haemodynamic response to exercise may reveal associations with LV structure and function not detected by traditional peripheral (brachial) measures in a younger population.

PURPOSE

To examine correlations between acute exercise-induced changes in central artery stiffness and wave reflections and measures of resting LV structure and function.

METHODS

Sixteen healthy men (age 26 ± 6 year; BMI 25·3 ± 2·7 kg m^-2 ) had measures of central haemodynamic load measured before/after a 30-s Wingate anaerobic test (WAT). Common carotid artery stiffness and reflected wave intensity were assessed via wave intensity analysis as a regional pulse wave velocity (PWV) and negative area (NA), respectively. Resting LV structure (LV mass) and function [midwall fractional shortening (mFS)] were assessed using M-mode echocardiography in the parasternal short-axis view.

RESULTS

There was a significant association between mFS and WAT-mediated change in carotid systolic BP (r = -0·57, P = 0·011), logNA (r = -0·58, P = 0·009) and PWV (r = -0·44, P = 0·045). There were no significant associations between resting mFS and changes in brachial systolic BP (r = -0·26, P>0·05). There were no associations between resting LV mass and changes in any haemodynamic variable (P>0·05).

CONCLUSION

Exercise-induced increases in central haemodynamic load reveal associations with lower resting LV function in young healthy men undetected by traditional peripheral haemodynamics.

Multimarker Analysis for New Biomarkers in Relation to Central Arterial Stiffness and Hemodynamics in a Chinese Community-Dwelling Population

Central arterial stiffness and hemodynamics independently reflect the risk of cardiovascular events. This Chinese community-based analysis was performed to evaluate the relationships of new biomarkers with central arterial stiffness and hemodynamics by a multimarker method. This analysis consisted of 1540 participants who were fully tested for the new biomarkers including N-terminal prohormone of brain natriuretic peptide, lipid accumulation product, triglyceride-high-density lipoprotein cholesterol (TG-HDL-c) ratio, uric acid, high-sensitivity C-reactive protein, and homocysteine. Carotid-femoral pulse wave velocity (cfPWV), central pulse pressure (cPP), and central augmentation index (cAIx) were measured. The median (range) age of entire cohort was 62 years (21-96 years), and 40.5% were males. The median (interquartile range) of cfPWV, cPP, and cAIx was 11.0 m/s (9.6-13.0 m/s), 42 mm Hg (35-52 mm Hg), and 28% (21%-33%), respectively. In multivariate analysis, participants with higher cfPWV had significantly higher age, peripheral pulse pressure, TG, TG-HDL-c ratio, and homocysteine levels compared with others (P < .05 for all). Multimarker analysis in a Chinese community-dwelling population reinforced the potential clinical value of plasma TG-HDL-c ratio and homocysteine levels as the biomarkers of increased arterial stiffness.

Relationship of arterial compliance and blood pressure with microalbuminuria and mildly decreased glomerular filtration rate: a Chinese community-based analysis

OBJECTIVE

This analysis is designed to determine the prevalence of microalbuminuria (MAU) and mildly decreased glomerular filtration rate (GFR); to investigate the association of augmentation index (AIx), central blood pressure (cBP) and peripheral blood pressure (pBP) with MAU and mildly decreased GFR; and to compare the association strength of cBP and pBP with MAU and mildly decreased GFR.

METHODS

This community-based analysis included 2071 Chinese residents. Urine albumin-to-creatinine ratio (UACR), GFR, and pulse wave measurements were performed. UACR of 30-299 mg/g and GFR of 60-89 ml/min/1.73 m2 were identified as MAU and mildly decreased GFR.

RESULTS

The prevalence of MAU and mildly decreased GFR was 21.3% and 33.2%. The AIx, cBP and pBP were significantly higher in participants with MAU compared with those without MAU, and in participants with mildly decreased GFR compared with those without mildly decreased GFR (all P<0.001). After participants were categorized into four subgroups based on the presence or absence of MAU and mildly decreased GFR, Aix, cBP and pBP progressively increased from the subgroup without both of MAU and mildly decreased GFR to the subgroups with either one of them, and arrived at top in the subgroup with both of them (all P<0.001). Compared with the reference category without MAU and mildly decreased GFR, the odd ratio values significantly increased from the category with either one of MAU and mildly decreased GFR to the category with both of them (all P<0.001). The AIx, cBP and pBP were all independently associated with MAU and mildly decreased GFR after full adjustment (all P<0.05), and the association strength of MAU and mildly decreased GFR with cBP was similar to those with pBP.

CONCLUSIONS

In Chinese community-dwelling population, there was a high prevalence of MAU and mildly decreased GFR. The AIx, cBP and pBP were all independently associated with MAU and mildly decreased GFR; meanwhile, cBP did not exhibit stronger association with MAU and mildly decreased GFR compared with pBP.

Brachial artery tonometry and the Popeye phenomenon: explanation of anomalies in generating central from upper limb pressure waveforms

BACKGROUND

Noninvasive applanation tonometry studies of the brachial and radial artery pressure waves show that the arterial pulse is substantially amplified between the brachial and radial sites. Brachial tonometry waveforms have also been used to calibrate carotid tonometry waves as a measure of central pressure in major clinical trials. These trials assume identity of mean and of DBP in calculation of central (carotid) SBP. None of these trials showed superiority of central over brachial pressure in predicting outcome, but all showed equivalence of SBP and pulse pressure at brachial and carotid sites!

METHOD

We tested this method by measuring pressure waves at brachial, radial and carotid sites by applanation tonometry in 100 patients, with attention to any subtle difference between brachial and radial waveforms, and with both calibrated to cuff SBP and DBP.

RESULTS

The results confirmed no proximal and strong distal amplification in the arm. However, this was accompanied by blunting of the brachial compared with radial waveform with brachial pressure 2.7 mmHg higher during most of the cardiac cycle. Form factor of the ensemble-averaged brachial wave [39.1 standard deviation (SD) 4.9%] was similar to the carotid (40.2 SD 4.1%) but different to the radial wave (34.8 SD 3.7%; P < 0.01).

CONCLUSIONS

All findings were explained by inability to applanate the brachial artery, and resulting systematic error in generating brachial waveforms. In estimation of central pressure with applanation tonometry, the radial pressure wave, which can be accurately applanated, should be used, and calibrated to the brachial cuff.

Resistance exercise training reduces arterial reservoir pressure in older adults with prehypertension and hypertension

We examined changes in central blood pressure (BP) following resistance exercise training (RET) in men and women with prehypertension and never-treated hypertension. Both Windkessel theory and wave theory were used to provide a comprehensive examination of hemodynamic modulation with RET. Twenty-one participants (age 61±1 years, n=6 male; average systolic blood pressure (SBP)/diastolic blood pressure (DBP)=138/84 mm Hg) were randomized to either 12 weeks of RET (n=11) or an inactive control group. Central BP and augmentation index (AIx) were derived from radial pressure waveforms using tonometry and a generalized transfer function. A novel reservoir-wave separation technique was used to derive excess wave pressure (related to forward and backward traveling waves) and reservoir pressure (related to the capacitance/Windkessel properties of the arterial tree). Wave separation using traditional impedance analysis and aortic flow triangulation was also applied to derive forward wave pressure (Pf) and backward wave pressure (Pb). There was a group-by-time interaction (P<0.05) for central BP as there was a significant ~6 mm Hg reduction in SBP and ~7 mm Hg reduction in DBP following RET with no change in the control condition. There were also group-by-time interactions (P<0.05) for Pf, excess wave pressure and reservoir pressure attributable to reductions in these parameters in the RET group concomitant with slight increases in the control group. There was no change in AIx or Pb (P>0.05). RET may reduce central BP in older adults with hypertension and prehypertension by lowering Pf and reservoir pressure without affecting pressure from wave reflections.

Relationship of central and peripheral blood pressure to left ventricular mass in hypertensive patients

INTRODUCTION AND OBJECTIVES

The purpose of the present study was to assess the relationship of central and peripheral blood pressure to left ventricular mass.

METHODS

Cross-sectional study that included 392 never treated hypertensive individuals. Measurement of office, 24-h ambulatory, and central blood pressure (obtained using applanation tonometry) and determination of left ventricular mass by echocardiography were performed in all patients.

RESULTS

In a multiple regression analysis, with adjustment for age, gender and metabolic syndrome, 24-h blood pressure was more closely related to ventricular mass than the respective office and central blood pressures. Systolic blood pressures always exhibited a higher correlation than diastolic blood pressures in all 3 determinations. The correlation between left ventricular mass index and 24-h systolic blood pressure was higher than that of office (P<.002) or central systolic blood pressures (P<.002). Changes in 24-h systolic blood pressure caused the greatest variations in left ventricular mass index (P<.001).

CONCLUSIONS

In our population of untreated middle-aged hypertensive patients, left ventricular mass index is more closely related to 24-h ambulatory blood pressure than to office or central blood pressure. Central blood pressure does not enable us to better identify patients with left ventricular hypertrophy.

Distribution of central blood pressure values estimated by Omron HEM-9000AI in the Japanese general population

Central blood pressure is more closely associated with cardiovascular events and target organ damage than peripheral blood pressure measured over the brachium using a conventional method. This study was designed to investigate the distribution of central systolic blood pressure values estimated by Omron HEM-9000AI in the Japanese general population. A cross-sectional study were performed in 10,756 subjects without overt cardiovascular disease (male=6574; mean age 55.3±12.5 years, range 20-91 years). Of these, 7348 subjects received no antihypertensive, antidiabetic or lipid-lowering drug treatment, and were used for the present analysis. Estimated central systolic blood pressure was higher than brachial systolic blood pressure and was significantly correlated with age and brachial blood pressure. The central systolic blood pressure values obtained from subjects without cardiovascular risk factors other than hypertension were 125.8±37.2 (mean±2 s.d., n=3760) mm Hg. The values obtained from subjects with no cardiovascular risk factors were 112.6±19.2 (n=1975) mm Hg for optimal and 129.2±14.9 mm Hg for normal brachial blood pressure categories (n=697). This study is the first to show the distribution of central systolic blood pressure values estimated using the Omron HEM-9000AI, marking an important step toward implementing the clinical use of central blood pressure in the diagnosis and management of hypertension.