Estimation of Central Systolic Blood Pressure from Peripheral Pressure Waves using a Novel Second Systolic Pressure-Based Method in Normal and Heritable Hypercholesterolemic Rabbits

AIM

Central systolic blood pressure (cSBP) was closely related to hypertension-related organ damage rather than peripheral systolic blood pressure (pSBP). We aimed to estimate cSBP from pSBP without generalized transfer function in normal and Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits aged 12 months.

METHODS

Two catheter-tip transducers were advanced into the ascending aorta (AA) and distal end of the right brachial artery (Br) through the right common carotid and right radial arteries, respectively, under pentobarbital anesthesia. Pressure waves in response to the intravenous administration of angiotensin II and sodium nitroprusside were simultaneously recorded in AA and Br under regular cardiac pacing.

RESULTS

The first (pSBP) and second peaks (pSBP2) of the brachial blood pressure and their average (pSBPm) were significantly correlated with cSBP, despite Murgo's wave pattern of central pressure waves in both rabbit groups. In Bland-Altman plot and its modification as a function of the peripheral augmentation index (pAI) analyses, the differences between pSBP and cSBP decreased, and those between pSBP2 and cSBP increased significantly in their average- or pAI-dependent manner, with undeniable mean biases in both rabbit groups. When the same analyses for SBPm were performed instead, the mean bias was around zero, with reduced variance in the two rabbit groups. The observed pressure or pAI-dependent systematic biases for pSBP and pSBP2 disappeared, representing the precise feature of pSBPm as a cSBP estimate.

CONCLUSIONS

We conclude that pSBPm could be more precise than pSBP2 as a cSBP estimate, irrespective of blood pressure levels, pAI, or the presence of atherosclerosis.

Noninvasive central hemodynamic monitoring in the primary care setting: improving prevention and management of cardiovascular diseases

Background

Although cardiovascular disease (CVD) has markedly declined since the early 1960s due to medical advances and better management, this condition persists as the most critical and preventable cause of death in the US. For that reason, the identification and application of more sensitive, specific, validated, and noninvasive biomarkers of cardiovascular functioning in the primary care setting for the early identification of CVD risk at the subclinical level are warranted.

Aim

The goal of the present review is twofold: first, to familiarize the primary care practitioner with noninvasive aortic hemodynamic parameters, including how these could be integrated into primary care services and patient management, and second, to propose a model for earlier detection of CVD based on the noninvasive hemodynamic parameters in the primary care setting.

Relevance for Patients

Implementation of noninvasive hemodynamic monitoring in a primary care setting could help in the identification of heart disease risk at the early onset thus preventing the need for expensive treatment or death at later stages.

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.

Markers of arterial stiffness and urinary metabolomics in young adults with early cardiovascular risk: the African-PREDICT study

INTRODUCTION

Increased exposure to risk factors in the young and healthy contributes to arterial changes, which may be accompanied by an altered metabolism.

OBJECTIVES

To increase our understanding of early metabolic alterations and how they associate with markers of arterial stiffness, we profiled urinary metabolites in young adults with cardiovascular disease (CVD) risk factor(s) and in a control group without CVD risk factors.

METHODS

We included healthy black and white women and men (N = 1202), aged 20-30 years with a detailed CVD risk factor profile, reflecting obesity, physical inactivity, smoking, excessive alcohol intake, masked hypertension, hyperglycemia, dyslipidemia and low socio-economic status, forming the CVD risk group (N = 1036) and the control group (N = 166). Markers of arterial stiffness, central systolic blood pressure (BP) and pulse wave velocity were measured. A targeted metabolomics approach was followed by measuring amino acids and acylcarnitines using a liquid chromatography-tandem mass spectrometry method.

RESULTS

In the CVD risk group, central systolic BP (adjusted for age, sex, ethnicity) was negatively associated with histidine, arginine, asparagine, serine, glutamine, dimethylglycine, threonine, GABA, proline, methionine, pyroglutamic acid, aspartic acid, glutamic acid, branched chain amino acids (BCAAs) and butyrylcarnitine (all P ≤ 0.048). In the same group, pulse wave velocity (adjusted for age, sex, ethnicity, mean arterial pressure) was negatively associated with histidine, lysine, threonine, 2-aminoadipic acid, BCAAs and aromatic amino acids (AAAs) (all P ≤ 0.044). In the control group, central systolic BP was negatively associated with pyroglutamic acid, glutamic acid and dodecanoylcarnitine (all P ≤ 0.033).

CONCLUSION

In a group with increased CVD risk, markers of arterial stiffness were negatively associated with metabolites related to AAA and BCAA as well as energy metabolism and oxidative stress. Our findings may suggest that metabolic adaptations may be at play in response to increased CVD risk to maintain cardiovascular integrity.

Relation between Oscillometric Measurement of Central Hemodynamics and Left Ventricular Hypertrophy in Hypertensive Patients

Introduction

The augmentation index (AIx) or central systolic blood pressure (SBP), measured by radial applanation tonometry, has been reported to be independently associated with left ventricular hypertrophy (LVH) in Japanese hypertensive patients. Cuff-based oscillometric measurement of the AIx using Mobil-O-Graph® showed a low or moderate agreement with the AIx measurement with other devices.

Methods

The AIx measured using the Mobil-O-Graph was validated against the tonometric measurements of the radial AIx measured using HEM-9000AI in 110 normotensive healthy individuals (age, 21-76 years; 50 men). We investigated the relationship between the central hemodynamics assessed using the Mobil-O-Graph and LVH in 100 hypertensive patients (age, 54-75 years; 48 men), presenting a wall thickness of ≥11 mm and ≥10 mm in men and women, respectively.

Results

Although the Mobil-O-Graph-measured central AIx showed no negative values, it correlated moderately with the HEM-9000AI-measured radial AIx (r = 0.602, p < 0.001) in the normotensive individuals. The hypertensive patients did not show a significant difference in the central SBP between the sexes, but the central AIx was lower in men than in women. The independent determinants influencing left ventricle (LV) mass index (LVMI) (R² = 0.362; adjusted R² = 0.329, p < 0.001) were heart rate (β = -0.568 ± 0.149, p < 0.001), central SBP (β = 0.290 ± 0.100, p = 0.005), and aortic root diameter (β = 1.355 ± 0.344, p = 0.001). Age (β = -0.025 ± 0.124, p = 0.841) and the central AIx (β = 0.120 ± 0.131, p = 0.361) were not independently associated with the LVMI. The area under the receiver operator characteristic curve to evaluate the diagnostic performance of the central AIx for the presence of LVH (LVMI >118 g/m² in men or >108 g/m² in women) was statistically significant in men (0.875, p < 0.001) but not in women (0.622, p = 0.132). In men, a central AIx of 28.06% had a sensitivity of 83.3% and specificity of 80.0% for detecting LVH.

Conclusions

AIx measurement in men provided useful prognostic information for the presence of LVH. Pulse-wave analysis assessed using the Mobil-O-Graph may be a valuable tool for detecting LVH in hypertensive patients.

The effect of acute aerobic exercise on central arterial stiffness, wave reflections, and hemodynamics in adults with diabetes: A randomized cross-over design

BACKGROUND

Individuals with diabetes have greater central arterial stiffness, wave reflections, and hemodynamics, all of which promote the accelerated cardiovascular pathology seen in this population. Acute aerobic exercise has been shown to be an effective strategy for reducing central arterial stiffness, wave reflections, and hemodynamics in healthy individuals; however, the effects of acute aerobic exercise in reducing these outcomes is not well established in people with diabetes. Recently, implementation of high-intensity interval exercise (HIIE) has shown superior improvements in cardiovascular health outcomes when compared to traditional aerobic exercise. Yet, the effect of HIIE on the aforementioned outcomes in people with diabetes is not known. The purpose of this study was to (i) describe the central arterial stiffness, wave reflections, and hemodynamic responses to a bout of HIIE and moderate-intensity continuous exercise (MICE) in adults with diabetes; and (ii) compare the effects of HIIE and MICE on the aforementioned outcomes.

METHODS

A total of 24 adult men and women (aged 29-59 years old) with type 1 (n = 12) and type 2 (n = 12) diabetes participated in a randomized cross-over study. All participants completed the following protocols: (i) HIIE: cycling for 4 × 4 min at 85%-95% of heart rate peak (HR_peak), interspersed with 3 min of active recovery at 60%-70%HR_peak; (ii) MICE: 33 min of continuous cycling at 60%-70%HR_peak; and (iii) control (CON): lying quietly in a supine position for 30 min.

RESULTS

A significant group × time effect was found for changes in central systolic blood pressure (F = 3.20, p = 0.01) with a transient reduction for the HIIE group but not for the MICE or CON groups. There was a significant group × time effect for changes in augmentation index at a heart rate of 75 beats/min (F = 2.32, p = 0.04) with a decrease following for HIIE and MICE but not for CON. For all other measures of central arterial stiffness and hemodynamics, no significant changes were observed (p > 0.05).

CONCLUSION

A bout of HIIE appears to lead to a greater transient reduction in central systolic blood pressure than the reduction observed following MICE; however, both HIIE and MICE improved augmentation index at a heart rate of 75 beats/min in people with diabetes. There was no significant difference in response to HIIE and MICE in all outcomes. This provides preliminary evidence on the role of HIIE on such outcomes in people with diabetes.

Evolution of isolated systolic hypertension with normal central blood pressure in adolescents-prospective study

BACKGROUND

The clinical significance of isolated systolic hypertension with normal central blood pressure known as spurious hypertension (sHT) in adolescents and its evolution over time is not known.

METHODS

The aim of this study was to analyze changes in office, ambulatory blood pressure (ABPM), central systolic blood pressure (cSBP), hemodynamic parameters, and target organ damage (TOD) over a 1-year follow-up in a group of non-obese children with sHT.

RESULTS

Of 294 patients referred for primary hypertension, 138 patients (31 girls; 22%) had hypertension confirmed by ABPM. 48/138 (35%) patients (7 girls; 15%) were diagnosed with sHT (elevated office and ambulatory systolic BP, but normal cSBP); 43 of them (6 girls; 14%) were followed for 12 ± 3 months during non-pharmacological therapy. At baseline 7 (16%) patients had borderline values of cIMT or LVMi indicating mild TOD. After 12 months, 10/43 (3 girls; 23%) patients developed sustained HT (elevated office, ambulatory BP and cSBP), 11/43 (1 girl; 26%) maintained sHT, and 22/43 (2 girls; 51%) evolved to white coat hypertension or normotension. The cSBP values increased in 27 patients (4 girls; 63%), but the group average remained in the normal range. Prevalence of TOD did not change during observation. The multivariate regression analysis showed that the only predictor of cSBP change over time was a change in serum uric acid level.

CONCLUSIONS

In conclusion, after 1 year of non-pharmacological treatment, 23% of adolescents with sHT developed sustained hypertension, with the main predictor of cSBP change being the change in serum uric acid.

Associations of central and peripheral blood pressure with the renin-angiotensin-aldosterone system in healthy young adults: the African-PREDICT study

This study investigated associations of brachial and central blood pressure (BP) with detailed renin-angiotensin-aldosterone system (RAAS) components in a healthy young population stratified according to ethnicity and sex. We included healthy black men (n = 285) and women (n = 304) and white men (n = 278) and women (n = 305) aged 20-30 years old. We derived central systolic BP (cSBP), measured clinic and 24-h systolic and diastolic BP. Aldosterone and equilibrium angiotensin levels were assessed and used for calculating angiotensin-derived markers for plasma renin activity (PRA-S, Angiotensin I + Angiotensin II), angiotensin-converting enzyme (ACE-S, Angiotensin II/Angiotensin I), and two markers for adrenal effects of angiotensin II, the aldosterone-to-renin ratio (ARR-S, Aldosterone/PRA-S) and the aldosterone-to-angiotensin II-ratio (AA2-R, Aldosterone/Angiotensin II)_. Young black men and women presented with lower RAAS components and higher cSBP compared to their white counterparts (all p ≤ 0.001). In multivariable-adjusted regression analyses, positive associations of cSBP with ARR-S and AA2-R and negative associations with PRA-S and angiotensin II were found for black women (all p ≤ 0.001); this pattern was also observed for 24-h and clinic BP (p ≤ 0.045). A similar trend of RAAS associations was present in black men but only for clinic BP (all p ≤ 0.047). In white men, negative associations between clinic SBP and PRA-S, angiotensin II and aldosterone were detected (all p ≤ 0.048). No associations were observed in white women. Positive associations of central and peripheral BP with the ratio of aldosterone to PRA-S and angiotensin II only in healthy, young black adults suggest that relative aldosterone excess may contribute to early hypertension development in this group.

Central Aortic Systolic Blood Pressure Exhibits Advantages Over Brachial Blood Pressure Measurements in Chronic Kidney Disease Risk Prediction in Women

BACKGROUND/AIMS

To investigate whether the invasively obtained central aortic systolic blood pressure (CSBP) predicts chronic kidney disease (CKD) better than brachial systolic blood pressure (SBP), brachial diastolic blood pressure (DBP) and brachial pulse pressure (PP) in the middle-aged Chinese population.

METHODS

A cross-sectional study was carried out across China in 2009-2010 among the subjects aged 35-64 years. CSBP was measured non-invasively by radial artery applanation tonometry B-pro (A-PULSE CASP and corresponding software). CSBP, SBP, DBP and PP were standardized with Z-score and the odds ratios were calculated with multivariable logistic regression model.

RESULTS

Data of 10197 participants were analyzed. The multivariable logistic regression after adjusting for possible confounders showed that a 1-standard deviation increment in each blood pressure measurement was associated with greater risk of CKD in both men and women (P < 0.05). The association of CSBP with CKD was stronger than SBP, DBP and PP in women, while in men the association of CSBP with CKD was stronger only than PP. With CSBP and SBP entering into the multivariable logistic regression models jointly, the odds ratio (95% confidence interval) for CSBP and SBP was 1.57 (1.39-1.79) and 1.22 (1.07-1.38) in women and 1.20 (1.03-1.39) and 1.48 (1.28-1.72) in men, respectively. With CSBP and DBP entering into the multivariable logistic regression models jointly, the odds ratio (95% confidence interval) for CSBP and DBP was 1.68 (1.52-1.84) and 1.15 (1.04-1.27) in women and 1.30 (1.15-1.46) and 1.45 (1.29-1.63) in men, respectively. With CSBP and PP entering into the multivariable logistic regression models jointly, the odds ratio (95% confidence interval) for CSBP and PP was 1.75 (1.58-1.94) and 1.06 (0.96-1.17) in women and 1.58 (1.41-1.77) and 1.04 (0.93-1.17) in men, respectively.

CONCLUSION

CSBP and brachial blood pressure measurements are all predictors of CKD, however the non-invasively obtained CSBP may offer advantages over brachial blood pressure measurements in CKD risk prediction in women.

Chlorthalidone Plus Amiloride Reduces the Central Systolic Blood Pressure in Stage 1 Hypertension Patients

BACKGROUND

Hypertension reduction strategies use blood pressure in the brachial artery as the primary endpoint. Individuals who achieve the target blood pressure reduction with antihypertensive treatment have residual cardiovascular risk attributed to the difference in pressure between the aorta and brachial artery. Antihypertensive treatment affects the intrinsic properties of the vascular wall and arterial stiffness markers and consequently the central pressure. Recent publications stress the importance of adequate control of the central compared to peripheral blood pressure. Related clinical implications suggest that individuals with normal peripheral but high central blood pressure should not receive antihypertensive drugs that act on the central pressure. Therefore, they are at greater cardiovascular risk. The aim of the study was to evaluate the effect of treatment with a thiazide diuretic versus losartan on the central blood pressure in stage 1 hypertensive patients.

METHODS

Twenty-five patients were randomized to the chlorthalidone 25 mg/amiloride 5 mg group (q.d.) and 25 patients received losartan 50 mg (b.i.d). The central systolic blood pressure (CSBP) and augmentation index (AIx 75) were assessed using applanation tonometry. The paired t-test was used to compare the systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), CSBP and AIx 75 between the thiazide and losartan groups at baseline and after 6 months of treatment.

RESULTS

Significant reductions in CSBP (123.3 ± 14.2 vs. 113.4 ± 111.4, P = 0.0103) and AIx 75 (87.7 ± 9.6 vs. 83.8 ± 8.9, P = 0.0289) were observed after 6 months of drug treatment with chlorthalidone 25 mg/amiloride 5 mg (q.d.). The administration of losartan 50 mg (b.i.d) did not reduce the CSBP and there were insignificant changes in the AIx 75.

CONCLUSIONS

Six-month treatment of chlorthalidone/amiloride but not losartan reduces the CSBP and AIx 75 in adults with stage 1 hypertension.

Serum glycated albumin, glycated hemoglobin, and arterial stiffness in a general Chinese population

BACKGROUND

Both glycated albumin (GA) and glycated hemoglobin (HbA1c) reflect the mean glucose levels. This study was conducted to investigate the relationships among GA, HbA1c, and arterial stiffness in the general population.

METHODS

A total of 11,014 participants were included. Serum GA; HbA1c; and arterial stiffness indices, including brachial-ankle pulse wave velocity (baPWV) and central systolic blood pressure (cSBP), were measured. Single-factor and multivariate regression analyses were performed. Receiver operating characteristic (ROC) analysis was performed to compare the predictive value of GA, HbA1c, and their combination for arterial stiffness. All analyses were stratified by sex.

RESULTS

Men had a lower GA level than women. GA, HbA1c, and plasma glucose levels were correlated. The levels of baPWV and cSBP increased across sex-specific quartiles of GA and HbA1c (P for trend<0.001 for all). Both GA and HbA1c were positively related to elevated baPWV and cSBP after adjusting for conventional factors (P<0.05 for all). These relationships remained significant when participants were divided into groups with normal glucose tolerance, prediabetes, or diabetes. Regarding screening for elevated baPWV and cSBP, the values of the area under the ROC curve (AUC) for GA were similar to those for HbA1c in men but were lower than those for HbA1c in women. The combination of GA and HbA1c did not improve the AUC compared with HbA1c alone.

CONCLUSIONS

Both GA and HbA1c were associated with arterial stiffness. The predictive value of GA for arterial stiffness was similar in men but lower in women compared with that of HbA1c.