Does Measurement of Central Blood Pressure have Treatment Consequences in the Clinical Praxis?

Relation of forward and backward traveling pressure waves with subclinical carotid artery wall remodeling and central pulse pressure

Central pulse pressure (PP) is the sum of forward and backward traveling pressure waves that have been associated with cardiovascular disease (CVD) risk. However, previous studies have reported differential findings regarding the importance of the forward versus the backward wave for CVD risk. Therefore, we sought to determine the degree to which the forward and backward pressure waves are associated with subclinical carotid artery wall remodeling and central PP in healthy adults. Using applanation tonometry, carotid pressure waveforms were acquired in 308 healthy individuals (aged 45 ± 17 years, range 19-80 years, 61% women), from which the time integral of the forward (PfTI) and backward (PbTI) pressure waves were derived via pressure-only wave separation analysis. Common carotid artery intima-media thickness (cIMT), a biomarker of subclinical CVD risk, was derived via B-mode ultrasonography measured ∼2 cm from the carotid bulb. Both PfTI (r = 0.31, P < 0.001) and PbTI (r = 0.40, P < 0.001) were correlated with cIMT. However, further analysis revealed that PbTI mediated the relation between PfTI and cIMT (proportion mediated = 156%, P < 0.001). The association between PbTI and cIMT remained after adjusting for age, sex, body mass index, blood glucose, low-density lipoprotein cholesterol, heart rate, brachial systolic pressure, and aortic stiffness (B = 0.02, 95% confidence interval = 0.01, 2.77, P < 0.001). Both PfTI (r = -0.58, P < 0.001) and PbTI (r = -0.50, P < 0.001) were correlated with central PP, however, PfTI fully mediated the association between PbTI and central PP (proportion mediated = 124%, P < 0.001). Although PfTI is correlated with higher central PP, it is PbTI that is directly associated with carotid artery wall remodeling.NEW & NOTEWORTHY The present study contributes to the growing body of evidence highlighting the physiological and clinical insight provided by the pulsatile hemodynamic components of central artery pulse pressure. The notable findings of this study are: 1) The reflected (backward) pressure wave is associated with carotid intima-media thickness independent of traditional cardiovascular risk factors, including systolic blood pressure and aortic stiffness. 2) The incident (forward) pressure wave, and not the reflected pressure wave, is associated with greater central pulse pressure.

Pharmacological treatment of hypertension guided by peripheral or central blood pressure: a comparison between the two strategies

Background

Arterial hypertension treatment guided by central blood pressures (CPB) rather than peripheral blood pressures (PBP) measurement has the potential to show greater effectiveness in preventing or even regressing stiffness and target organ damage (TOD).

Objective

This study aimed to compare the parameters of CBP and PBP measurements, arterial stiffness, TOD and renal profile in patients with anti-hypertensive treatment guided by CBP or PBP targets.

Methods

A randomized clinical trial was conducted in central group (CG) and peripheral group (PG). Patients were randomized, evaluated every 3 months for BP and antihypertensive adjustments during a one-year follow up. The procedures in V1 and V5: anthropometric assessment; CBP/PBP measurements, carotid ultrasound; echocardiography; laboratory tests. Paired and unpaired t-tests and the χ2 were used (significance level: 5%).

Results

The study evaluated 59 participants (30CG/29PG). The augmentation index (AIx) was higher in the CG (27.3% vs. 20.3%, p = 0.041). Intergroup analysis has found central diastolic BP lower in the CG (78.9 vs. 84.3 mmHg, p = 0.024) and the Alx difference between groups ceased to exist after a one-year follow-up. Intragroup comparisons, after intervention, showed a lower frequency of changed PWV (p < 0.001) and LVMI (p = 0.018) in the CG. The PG showed a higher frequency of changed PWV (p < 0.001) and LVMI (p = 0.003).

Conclusion

The intervention guided by central BP reduced the central diastolic BP and AIx compared to the PG. There was a reduction in the frequency of changed PWV and LVMI in the CG.

SAGE Score in Normotensive and Pre-Hypertensive Patients: A Proof of Concept

BACKGROUND

The SAGE score was developed to detect individuals at risk for increased pulse wave velocity (PWV). So far, studies have been focused on hypertensive patients.

OBJECTIVE

To assess the ability of the score to detect non-hypertensive and pre-hypertensive patients at risk for increased PWV.

METHODS

Retrospective cross-sectional study of analysis of central blood pressure data and calculation of the SAGE score of non-hypertensive and pre-hypertensive patients. Each score point was analyzed for sensitivity, specificity, positive and negative predictive values, using the cut-off point for positive diagnosis a PVW ≥ 10m/s, ≥9.08 m/s (75thpercentile) and ≥7.30 m/s (50thpercentile). A p<0.05 was considered statistically significant.

RESULTS

The sample was composed of 100 normotensive and pre-hypertensive individuals, with mean age of 52.64 ± 14.94 years and median PWV of 7.30 m/s (6.03 - 9.08). The SAGE score was correlated with age (r=0.938, p<0.001), glycemia (r=0.366, p<0.001) and glomerular filtration rate (r=-0.658, p<0.001). The area under the ROC curve was 0.968 (p<0.001) for PWV ≥ 10 m/s, 0.977 (p<0.001) for PWV ≥ 9.08 m/s and 0.967 (p<0.001) for PWV ≥ 7.30 m/s. The score 7 showed a specificity of 95.40% and sensitivity of 100% for PWV≥10 m/s. The cut-off point would be of five for a PWV≥9.08 m/s (sensitivity =96.00%, specificity = 94.70%), and two for a PWV ≥ 7.30 m/s.

CONCLUSION

The SAGE score could identify individuals at higher risk of arterial stiffness, using different PWV cutoff points. However, the development of a specific score for normotensive and pre-hypertensive subjects is needed.

Relationship between Pulse Wave Velocity and Cardiovascular Biomarkers in Patients with Risk Factors

BACKGROUND

The relationship between pulse wave velocity (PWV) and biomarkers of structural changes of the left ventricle and carotid arteries remains poorly understood.

OBJECTIVE

To investigate the relationship between PWV and these biomarkers.

METHODS

This was an analytical, retrospective, cross-sectional study. Medical records of patients with diabetes mellitus, dyslipidemia, and pre-hypertension or hypertension, who underwent central blood pressure (CBP) measurement using Mobil-O-Graph®, and carotid doppler or echocardiography three months before and after the CBPM were analyzed. Statistical analysis was performed using Pearson or Spearman correlation, linear bivariate and multiple regression analysis, and the t test (independent) or Mann-Whitney test. A p <0.05 indicated statistical significance.

RESULTS

Medical records of 355 patients were analyzed, mean age 56.1 (±14.8) years, 51% male. PWV was correlated with intima-media thickness (IMT) of carotids (r=0.310) and left ventricular septal thickness (r=0.191), left ventricular posterior wall thickness (r=0.215), and left atrial diameter (r=0.181). IMT was associated with PWV adjusted by age and peripheral systolic pressure (p=0.0004); IMT greater than 1 mm increased the chance of having PWV above 10 m/s by 3.94 times. PWV was significantly higher in individuals with left ventricular hypertrophy (p=0.0001), IMT > 1 mm (p=0.006), carotid plaque (p=0.0001), stenosis ≥ 50% (p=0.003), and target-organ damage (p=0.0001).

CONCLUSION

PWV was correlated with IMT and echocardiographic parameters, and independently associated with IMT. This association was stronger in individuals with left ventricular hypertrophy, increased IMT, carotid plaque, stenosis ≥ 50%, and target organ damage. (Arq Bras Cardiol. 2020; 115(6):1125-1132).

Feasibility of Non-invasive Pulse Pressure Measurement Using the Phased-Tracking Method

Phased tracking (PT) is a high-precision ultrasonic technology that enables measurements of pulse pressure (PP). The aim of this study was to verify the accuracy of estimated PP using PT. Estimated PPs were compared with measured PPs in three sheep fetuses that were connected to an artificial placenta system. Similarly, estimated and measured PPs of 30 human neonates were compared. PP was calculated using the Water-Hammer equation (PP = ρ × PWV (pulse wave velocity) × ΔU). PWV was estimated by measuring the transit times of pulse waves at two sites along the aorta using the PT method, and ΔU was obtained by subtracting end-diastolic velocity from peak systolic velocity. The correlation between the estimated and measured PPs of the sheep fetuses was strong (r = 0.95, p ˂ 0.01), as was the case with the human neonates (r = 0.88, p ˂ 0.05). It can be concluded from the results of this study that PT may be a non-invasive alternative method used to predict PP.

Aortic pressure and forward and backward wave components in children, adolescents and young-adults: Agreement between brachial oscillometry, radial and carotid tonometry data and analysis of factors associated with their differences

Non-invasive devices used to estimate central (aortic) systolic pressure (cSBP), pulse pressure (cPP) and forward (Pf) and backward (Pb) wave components from blood pressure (BP) or surrogate signals differ in arteries studied, techniques, data-analysis algorithms and/or calibration schemes (e.g. calibrating to calculated [MBPc] or measured [MBPosc] mean pressure). The aims were to analyze, in children, adolescents and young-adults (1) the agreement between cSBP, cPP, Pf and Pb obtained using carotid (CT) and radial tonometry (RT) and brachial-oscillometry (BOSC); and (2) explanatory factors for the differences between approaches-data and between MBPosc and MBPc.1685 subjects (mean/range age: 14/3-35 y.o.) assigned to three age-related groups (3–12; 12–18; 18–35 y.o.) were included. cSBP, cPP, Pf and Pb were assessed with BOSC (Mobil-O-Graph), CT and RT (SphygmoCor) records. Two calibration schemes were considered: MBPc and MBPosc for calibrations to similar BP levels. Correlation, Bland-Altman tests and multiple regression models were applied. Systematic and proportional errors were observed; errors´ statistical significance and values varied depending on the parameter analyzed, methods compared and group considered. The explanatory factors for the differences between data obtained from the different approaches varied depending on the methods compared. The highest cSBP and cPP were obtained from CT; the lowest from RT. Independently of the technique, parameter or age-group, higher values were obtained calibrating to MBPosc. Age, sex, heart rate, diastolic BP, body weight or height were explanatory factors for the differences in cSBP, cPP, Pf or Pb. Brachial BP levels were explanatory factors for the differences between MBPosc and MBPc.

Impact of Methodological and Calibration Approach on the Association of Central and Peripheral Systolic Blood Pressure with Cardiac Structure and Function in Children, Adolescents and Adults

INTRODUCTION

Peripheral and aortic systolic blood pressure (pSBP and aoSBP) were measured using different methodological and calibration approaches to analyze the association and agreement between pSBP and/or aoSBP, and the association of pSBP and aoSBP with left ventricle (LV) and atrium (LA) structural-functional characteristics.

METHODS

In healthy subjects (n = 269, age: 9-85 years; n = 147, age < 24 years) LV and LA parameters were echocardiography-derived. pSBP and aoSBP were obtained by brachial sub-diastolic (Mobil-O-Graph^®) and supra-systolic oscillometry (Arteriograph^®) and aortic diameter waveform re-calibration (RCD; ultrasonography), using three calibration schemes: systo-diastolic (SD), calculated mean (CM), and oscillometric mean (OscM).

RESULTS

Always pSBP and aoSBP were positively associated; aoSBP obtained with the Mobil-O-Graph^® and calibrated to CM or OscM were the ones that showed the lowest levels of association with the remaining forms of aoSBP and pSBP. Bland-Altman related mean errors varied noticeably (e.g. - 27, - 23, - 17, - 12 or 8 mmHg when aoSBP obtained with MOG (OscM) was compared with data from other methodological and calibration schemes). The aoSBP data obtained with Mobil-O-Graph^® (calibration: CM and OscM) showed the highest levels of association with cardiac structural characteristics. aoSBP values obtained calibrating to OscM were higher than those obtained calibrating to SD or CM.

CONCLUSIONS

aoSBP obtained with Mobil-O-Graph^® and calibrated to CM or OscM showed (1) lower association with other forms of aoSBP and pSBP determination and (2) higher levels of association with LV and LA structural characteristics. Differences in aoSBP data between approaches were more sensitive to the calibration method than to the device used.

Incorporation of Novel Vascular Measures into Clinical Management: Recent Insights from the Framingham Heart Study

PURPOSE OF REVIEW

The review discusses evidence from the Framingham Heart Study that supports the assessment and utility of novel vascular and blood pressure measures to inform clinical management of blood pressure-related cardiovascular disease.

RECENT FINDINGS

Recent Framingham Heart Study investigations provide new insights into the associations of novel and traditional vascular and blood pressure measures, such as measures of aortic stiffness, components of blood pressure waves, and orthostatic change in blood pressure, with cardiovascular disease events and brain structure and function. Novel vascular measures provide opportunities for additional investigation and potential development of new interventions that are more precisely targeted at underlying pathophysiology. Inclusion of novel vascular measures should be considered in clinical practice to screen for early, subclinical disease and to stratify high-risk individuals for targeted therapies.