Augmentation index in the assessment of wave reflections and systolic loading

BACKGROUND

Augmentation index (AI_x) is used to quantify the augmented systolic aortic pressure that impedes ventricular ejection. Its use as an index of wave reflections is questionable. We hypothesize that AI_x is quantitatively different from the reflection coefficient under varied physiological conditions.

METHODS

42 datasets of aortic pressure and flow waveforms were obtained during induced hypertension (methoxamine infusion) and vasodilation (nitroprusside infusion) in our mongrel dog experiments (n = 5) and from Mendeley data during various interventions (vasoconstrictors, vasodilators, pacing, stimulation, hemorrhage and hemodilution). Wave reflections and principal components of reflection coefficients were computed for comparison to AI_x and heart rate normalized AI_x. RESULTS: Principal reflection coefficient, Γ₁, increased in hypertension and decreased in vasodilation, hemorrhage and hemodilution. AI_x followed the trend in many cases but was consistently lower than Γ₁ in almost all the subjects. The Bland-Altman analysis also showed that both AI_x and normalized AI_x underestimated Γ₁. The relationship between augmentation index and reflection coefficient was explained by a linear regression model (r² = 0.23, p < 0.01) in which AI_x followed directional changes in Γ₁ and the normalization of AI_x resulted in a linear model that explained less variation in the relationship between AI_x and Γ₁.

CONCLUSION

AI_x is a reasonable clinical trend indicator, albeit not an accurate surrogate measure of the amount of wave reflections.

Aortic Augmentation Index is Dependent on Bodyside in Healthy Young Subjects

INTRODUCTION

Aortic augmentation index (AIx) is a commonly used measure to evaluate the arterial stiffness of large elastic arteries. It has been used as an indicator for cardiovascular risk in clinical practice.

AIM

To evaluate the difference in the aortic AIx assessed from the left and the right hand in a group of healthy young adults using SphygmoCor and Arteriograph devices.

METHODS

32 subjects were enrolled in this study (27 ± 7 years), 16 male and 16 female volunteers participated. Equally, half of the gender groups were left-handed and another half right-handed.

RESULTS

It was found that the aortic AIx values assessed from the pressure waveforms of the right and the left hand are different and significantly higher in the left hand. Using a SphygmoCor device, the mean difference between the aortic AIx values from the right and the left hand among the whole study group was found - 4.78 ± 4.31% and using an Arteriograph the aortic AIx values were - 3.92 ± 3.90%. Aortic AIx values assessed from the right and the left hand were linearly related to each other for both devices. Moreover, it was found that the values of the aortic.

CONCLUSIONS

AIx are independent of the subject's handedness. It has to be pointed out that subjects who cannot be subjected to assessment of the aortic AIx from one side of the body could have different AIx values estimated from the recorded pressure waveform from the other bodyside.

Establishing the interchangeability of arterial stiffness but not endothelial function parameters in healthy individuals

Background

Development of instruments capable of detecting early stage vascular disease has increased interest in employing arterial stiffness (e.g. pulse wave velocity (PWV), augmentation index (AIx)) and endothelial dysfunction (e.g. reactive hyperemia index (RHI)) to diagnose atherosclerotic disease before occurrence of a cardiovascular event. However, amongst the equipment designed for this purpose, there is insufficient information regarding each of these parameters to establish appropriate cutoffs to distinguish between healthy and unhealthy blood vessels. To address these limitations, the study was designed to establish the upper arterial stiffness and endothelial function thresholds in a healthy population, by comparing the outputs from different instruments capable of measuring PWV, AIx and RHI.

Methods

A systematic comparison of PWV, AIx and RHI was conducted to determine the inter-relationships between these parameters of vascular functionality. Outputs were obtained non-invasively using three instruments, the VP-1000 (VP), SphygmoCor (SC), and EndoPAT (EP), in 40 apparently healthy males and females.

Results

Correlations were found between the brachial-ankle PWV and radial-ankle PWV (by VP and SC), and PWV (VP) with AIx (SC). The interchangeability of these outputs was demonstrated by the Bland Altman test, making it feasible to extrapolate cut-offs for radial-ankle PWV and AIx equivalent to brachial-ankle PWV that signify healthy vessels. In contrast, RHI showed no association with AIx, suggesting these endothelial and arterial parameters are functionally distinct.

Conclusions

It was concluded that it is possible to compare the vascular function outputs of different instruments and identify healthy from unhealthy vessels, even though the approaches for quantifying the underlying physiological processes may differ. In this way, non-invasive determination of arterial function could be a new paradigm for detecting existing early stage asymptomatic atherosclerotic disease in individuals using techniques that are amenable to the clinical setting.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1167-3) contains supplementary material, which is available to authorized users.

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.

Arterial stiffness in Familial Mediterranean Fever: correlations with disease-related parameters and colchicine treatment

INTRODUCTION/OBJECTIVES

Familial Mediterranean Fever is the most common autoinflammatory disease. As chronic inflammation may result in increased arterial stiffness, we aimed to investigate indices of arterial stiffness in patients with Familial Mediterranean Fever and their associations with disease-related factors and colchicine treatment.

METHOD

The study was conducted with 43 patients with Familial Mediterranean Fever, including 30 children, in attack free period and 42 healthy controls. Arterial stiffness was assessed by carotid-femoral pulse wave velocity and augmentation index.

RESULTS

Patients with Familial Mediterranean Fever presented similar carotid-femoral pulse wave velocity values to controls, but significantly higher augmentation index values (patients versus controls, 19.76% and 9.96%, P < 0.05). Augmentation index, adjusted for age and sex, was associated with complete response compared with partial response to treatment (B = - 17.78, 95% CI - 31.17 to - 4.40, P < 0.05) and the presence of M694V.M680I genotype (B = - 16.75, 95% CI - 33.81 to 0.30, P = 0.05). Carotid-femoral pulse wave velocity presented an inverse relationship with colchicine treatment duration (B = - 0.003, 95% CI - 0.006 to - 0.00, P < 0.05). Pulse wave velocity values adjusted for age and systolic blood pressure were associated with attack frequency (B = 0.48, 95% CI 0.01 to 0.96, P < 0.05). Addition of colchicine treatment duration to the model attenuated the association between carotid-femoral pulse wave velocity and attack frequency supporting the protective role of colchicine.

CONCLUSIONS

The normal values of carotid-femoral pulse wave velocity in Familial Mediterranean Fever patients may reflect the compliance to colchicine treatment, which seems to have a protective role against arterial stiffness. However, the increased values of augmentation index need further investigation.

KEY POINTS

• FMF patients are prone to present increased cardiovascular risk possibly due to inflammation. • Colchicine treatment may have protective role against arterial stiffness in FMF. • The normal values of cf-PWV in FMF patients may reflect the compliance to colchicine.

Cardiorespiratory fitness predicts cardiovascular health in breast cancer survivors, independent of body composition, age and time post-treatment completion

BACKGROUND

Breast cancer treatment may increase non-cancer related mortality risk due to unintended cardiovascular consequences. The aim of this study was to investigate the strongest correlate of cardiovascular health (CVH) in female breast cancer survivors, cardiorespiratory fitness or fatness.

METHODS

Fifty-one women (59 ± 9 years, BMI 26.4 ± 4.8 kg/m²) previously diagnosed and treated for primary breast cancer were assessed using pulse wave analysis to determine central arterial wave reflection (augmentation index, AIx) and central systolic blood pressure (cSBP). A composite Z score calculated which incorporated central double product and AIx, as an indicator of CVH. Dual energy X-ray absorptiometry was used to obtain total body fat percentage (BF%). Cardiorespiratory fitness was determined using the single-stage walk test to predict maximal oxygen uptake ([Formula: see text]).

RESULTS

Linear regression analysis revealed that fitness was associated with AIx after adjusting for BF %, age and time post-treatment completion (β = - 0.271, p = 0.010). A significant association between BF% and AIx after adjusting for fitness and age was found (β = 0.166, p = 0.0005); however, this association was lost when time post-treatment was included in the model (β = 0.166, p = 0.167). Both fitness (β = - 0.347, p = 0.0005) and BF% (β = 0.333, p = 0.013) were independently associated with CVH in the fully adjusted model.

CONCLUSIONS

This study provides evidence for an association between cardiorespiratory fitness and cardiovascular health in female breast cancer survivors. While fatness may be associated with cardiovascular health, it appears to be more strongly associated with age.

Parameters of arterial stiffness in patients with Behçet's disease and their relationship with disease duration

The results of investigations of arterial stiffness in Behçet's disease (BD) are contradictory and the reason for this contradictory situation is not clear. The lack of studies in homogenous groups according to the duration of the disease may be the cause of conflicting results. To compare arterial stiffness by assessing pulse wave velocity (PWV) and augmentation index (AIx) measurements in healthy controls (HC) and patients diagnosed with BD with short and long disease duration. This cross-sectional study was conducted between August-November 2017 and 54 patients with BD and 34 HC were included. Patients with BD who were diagnosed within 12 months were included in the group with short disease duration (SDD) and the others in the group with long disease duration (LDD). Parameters of cardiovascular risk of all participants were recorded and PWV and AIx values were measured from the brachial artery. AIx was significantly higher in all patients with BD, patients with BD with SDD and patients with BD with LDD, than in HC (p = 0.005, p = 0.011, p = 0.004, respectively). Pulse wave velocity values were not different from HC in patients with BD. When patients with BD with SDD and LDD were compared with each other, PWV was significantly higher in patients with BD with LDD (p = 0.030). There was a moderate correlation between PWV and disease duration (Rho = 0.414, p = 0.002). Augmentation index is higher in patients with BD than HC regardless of disease duration.

Heart Failure-Specific Relationship Between Muscle Sympathetic Nerve Activity and Aortic Wave Reflection

BACKGROUND

Reflected arterial waves contribute to left ventricular (LV) afterload. Heart failure patients with reduced ejection fraction (HFrEF) are afterload sensitive and sympathetically activated. We tested the hypothesis that HFrEF patients exhibit a positive relationship between sympathetic vasoconstrictor discharge and aortic wave reflection.

METHODS

Sixteen treated patients with HFrEF (61 ± 9 years of age, left ventricular ejection fraction 30 ± 7%, 3 women) and 16 similar-aged healthy control subjects (57 ± 7 years of age, 4 women) underwent noninvasive measurements of radial pulse waveforms (applanation tonometry) to calculate central blood pressures and aortic wave reflection characteristics: augmentation pressure (AP), augmentation index (AI_x), and AI_x corrected to a heart rate of 75 beats/min (AI_x@75). Muscle sympathetic nerve activity (MSNA) burst frequency was recorded from the fibular nerve (microneurography).

RESULTS

HFrEF patients had higher AI_x (26 ± 9 vs 17 ± 15%; P < .05) and MSNA burst frequency (48 ± 7 vs 39 ± 11 bursts/min; P < .05) and lower central diastolic pressure than control subjects (64 ± 8 vs 70 ± 9 mm Hg; P = 0.05). There were no between-group differences in heart rate, other measures of blood pressure (brachial and central; P > .05), AP (11 ± 5 vs 7 ± 8 mm Hg; P = 0.11), or AI_x@75 (19 ± 9 vs 13 ± 11%,-P = 0.14). MSNA correlated positively with AP (r = 0.50; P < .05), AI_x (r = 0.51; P < .05), and AI_x@75 (r = 0.54; P < .05) in HFrEF patients but not in control subjects (r = 0.002-0.18; P > 0.49).

CONCLUSIONS

In patients with HFrEF, but not similarly aged healthy subjects, indices of aortic wave reflection correlate positively with MSNA. By increasing LV afterload, such neurovascular coupling could impair LV performance and worsen heart failure symptoms. Therapies that attenuate neurogenic vasoconstriction may benefit HFrEF patients by diminishing arterial wave reflection.

Radial Artery Tonometry is Associated With Major Adverse Cardiac Events in Patients With Peripheral Artery Disease

BACKGROUND

Peripheral artery disease (PAD) is associated with increased arterial stiffness, as measured by an increasing radial artery augmentation index (AIX). However, it has not yet been clearly demonstrated whether AIX is associated with adverse cardiovascular outcomes in a PAD population.

MATERIALS AND METHODS

Seventy-two patients with PAD were recruited between 2011 and 2016. Radial artery applanation tonometry was performed at a baseline visit, and the central AIX, normalized to 75 beats/min, and the peripheral AIX were calculated using pulse wave analysis. Incident major adverse cardiac events (MACEs) were identified by subsequent chart review.

RESULTS

Study subjects had comorbidities commonly associated with PAD including a high prevalence of hypertension (93%), hyperlipidemia (85%), coronary artery disease (39%), and diabetes mellitus (39%). During a median follow-up period of 34 mo (interquartile range 29-38), 14 patients experienced a MACE. In a univariate Cox proportional hazards model, a 10-unit increase in the peripheral AIX was significantly associated with a 54% increased rate of MACE (hazard ratio [HR] 1.54, 95% confidence interval [CI] 1.06-2.22, P = 0.02), but central AIX, normalized to 75 beats/min, was not (HR 1.33, 95% CI 0.71-2.47, P = 0.37). In a multivariable model adjusted for coronary artery disease, age, and Rutherford category the peripheral AIX remained significantly associated with MACE (HR 1.70, 95% CI 1.10-2.62, P = 0.02).

CONCLUSIONS

Increased arterial stiffness, as measured by the peripheral AIX, was independently associated with an increased rate of MACE in patients with PAD. The use of radial artery tonometry should be contemplated as a tool for risk stratification in patients with PAD.

Peripheral maternal haemodynamics across pregnancy in hypertensive disorders of pregnancy

OBJECTIVES

Evaluating maternal haemodynamics across pregnancy in uncomplicated pregnancies and those complicated by hypertensive disorders of pregnancy (HDP).

STUDY DESIGN

Prospective cohort study from 2015 to 2018 of healthy, nulliparous, singleton-bearing women. Maternal haemodynamics assessed by Uscom BP+ at 9-16 and 32-36 weeks' gestation in pregnancies complicated by HDP [preeclampsia with severe (sPE n = 12) and without severe clinical features (nsPE n = 49), gestational hypertension (GH n = 25), transient gestational hypertension (TGH n = 33)] were compared to uncomplicated pregnancies (n = 286) using mixed-effects linear modelling.

MAIN OUTCOME MEASURES

Maternal haemodynamic adaptation in uncomplicated pregnancies and those complicated by HDP.

RESULTS

Between the two measurements, haemodynamic adaptation in women with sPE and nsPE was significantly different compared to those with uncomplicated pregnancies. An additional increase was observed for peripheral systolic blood pressure [SBP; 14.3 mmHg, 8.6-20.1 (sPE)], peripheral diastolic blood pressure [DBP; 7.7 mmHg, 3.3-12.1 (sPE); 2.6 mmHg, 3.3-12.1 (nsPE)] peripheral mean arterial pressure [MAP; 10.6 mmHg, 5.8-15.5 (sPE); 3.4 mmHg, 0.8-6.0 (nsPE)], peripheral pulse pressure [PP; 6.6 mmHg, 2.1-11.1 (sPE)], central SBP [15.8 mmHg, 10.4-21.2 (sPE); 2.9 mmHg, 0.1-5.8 (nsPE)], central DBP [8.3 mmHg, 3.9-12.6 (sPE); 2.5 mmHg, 0.2-4.8 (nsPE), central MAP [10.8 mmHg, 6.4-15.2 (sPE); 2.6 mmHg, 0.3-5.0 (nsPE)] and central PP [7.6 mmHg, 3.9-11.3 (sPE)]. Augmentation index (AIx) decreased less (15.5%, 6.3-24.6 (sPE); 9.0%, 4.2-13.6 (nsPE)] compared to uncomplicated pregnancies. Haemodynamic adaptation across pregnancy in women with GH and TGH was not different from those with uncomplicated pregnancies.

CONCLUSION

Women who develop preeclampsia show an altered, while those who develop GH or TGH demonstrate a comparable haemodynamic adaptation compared to uncomplicated pregnancies. TGH is not a benign condition.

Effects of acute dietary nitrate supplementation on aortic blood pressures and pulse wave characteristics in post-menopausal women

PURPOSE

Consumption of nitrate-rich beetroot juice can lower blood pressure in peripheral as well as central arteries and may exert additional hemodynamic benefits (e.g. reduced aortic wave reflections). The specific influence of nitrate supplementation on arterial pressures and aortic wave properties in postmenopausal women, a group that experiences accelerated increases in these variables with age, is unknown. Accordingly, the primary aim of this study was to determine the effect of consuming nitrate-rich beetroot juice on resting brachial and aortic blood pressures (BP) and pulse wave characteristics in a group of healthy postmenopausal women, in comparison to a true (nitrate-free beetroot juice) placebo.

METHODS

Brachial (oscillometric cuff) and radial (SphygmoCor) pressures and derived-aortic waveforms were measured during supine rest in thirteen healthy postmenopausal women (63 ± 1 yr) before and 100 min after consumption of 140 ml of either nitrate-rich (9.7 mmol, 0.6 gm NO₃^-) or nitrate-depleted beetroot juice on randomized visits approximately 10 days apart (cross-over design). Ten young premenopausal women (22 ± 1 yr) served as a reference (non-supplemented) cohort.

RESULTS

Brachial and derived-aortic variables showed the expected age-associated differences in these women (all p < 0.05). In post-menopausal women, nitrate supplementation reduced (p < 0.05 vs. placebo visit) brachial systolic BP (BR_nitrate -4.9 ± 2.1 mmHg vs BR_placebo +1.1 ± 1.8 mmHg), brachial mean BP (BR_nitrate -4.1 ± 1.7 mmHg vs BR_placebo +0.9 ± 1.3 mmHg), aortic systolic BP (BR_nitrate -6.3 ± 2.0 mmHg vs BR_placebo +0.5 ± 1.7 mmHg) and aortic mean BP (BR_nitrate -4.1 ± 1.7 mmHg vs BR_placebo +0.9 ± 1.3 mmHg), and increased pulse pressure amplification (BR_nitrate +4.6 ± 2.0% vs BR_placebo +0.7 ± 2.5%, p = 0.04), but did not alter aortic pulse wave velocity or any other derived-aortic variables (e.g., augmentation pressure or index).

CONCLUSIONS

Dietary nitrate supplementation favorably modifies aortic systolic and mean blood pressure under resting conditions in healthy postmenopausal women. Acute supplementation of nitrate does not, however, appear to restore indices of aortic stiffness in this group. Future work should evaluate chronic, long-term effects of this non-pharmacological supplement.

A compact pulsatile simulator based on cam-follower mechanism for generating radial pulse waveforms

Background

There exists a growing need for a cost-effective, reliable, and portable pulsation simulator that can generate a wide variety of pulses depending on age and cardiovascular disease. For constructing compact pulsation simulator, this study proposes to use a pneumatic actuator based on cam-follower mechanism controlled by a DC motor. The simulator is intended to generate pulse waveforms for a range of pulse pressures and heart beats that are realistic to human blood pulsations.

Methods

This study first performed in vivo testing of a healthy young man to collect his pulse waveforms using a robotic tonometry system (RTS). Based on the collected data a representative human radial pulse waveform is obtained by conducting a mathematical analysis. This standard pulse waveform is then used to design the cam profile. Upon fabrication of the cam, the pulsatile simulator, consisting of the pulse pressure generating component, pressure and heart rate adjusting units, and the real-time pulse display, is constructed. Using the RTS, a series of testing was performed on the prototype to collect its pulse waveforms by varying the pressure levels and heart rates. Followed by the testing, the pulse waveforms generated by the prototype are compared with the representative, in vivo, pulse waveform.

Results

The radial Augmentation Index analysis results show that the percent error between the simulator data and human pulse profiles is sufficiently small, indicating that the first two peak pressures agree well. Moreover, the phase analysis results show that the phase delay errors between the pulse waveforms of the prototype and the representative waveform are adequately small, confirming that the prototype simulator is capable of simulating realistic human pulse waveforms.

Conclusions

This study demonstrated that a very accurate radial pressure waveform can be reproduced using the cam-based simulator. It can be concluded that the same testing and design methods can be used to generate pulse waveforms for other age groups or any target pulse waveforms. Such a simulator can make a contribution to the research efforts, such as development of wearable pressure sensors, standardization of pulse diagnosis in oriental medicine, and training medical professionals for pulse diagnosis techniques.

Association of HIV-infection, antiretroviral treatment and metabolic syndrome with large artery stiffness: a cross-sectional study

Background

Effective combined antiretroviral therapy (cART) has improved life expectancy among people living with HIV-1 infection. Treated HIV-1infection increases the prevalence of metabolic syndrome (MS). Despite sub-Saharan Africa having among the highest rates of HIV-1 infection, the effects of MS in HIV-1-infected individuals on cardiovascular risk is poorly explored. The aim of the study was to assess whether MS and/or HIV-1 treatment correlates with large elastic artery stiffness in HIV-1-infected patients treated with first-line cART.

Methods

The study sample comprised of 102 subjects free of cardiovascular disease and major risk factors divided into two groups based on HIV-1 infection, treatment, and MS status: HIV-1⁺/cART⁺/MS⁺ (n = 12); HIV-1⁺/cART⁻/MS⁺ (n = 16); HIV-1⁻/ MS⁺ (n = 10); HIV-1⁺/cART⁺/MS⁻ (n = 42); HIV-1⁺/cART⁻/MS⁻ (n = 32); HIV-1⁻/ MS⁻ (n = 39). MS was established according the International Diabetes Federation definition. Large artery stiffness was measured using applanation tonometry to assess aortic pulse wave velocity (aPWV) and aortic augmentation index at heart rate of 75 bpm (AIx@HR75). cART included lamivudine/zidovudine and nevirapine or efavirenz.

Results

The prevalence of MS in the HIV-1-infected patients was 28%. There were no significant differences in aPWV in the non-MS groups. However, in subjects with MS, aPWV was significantly higher in the HIV-1 cART patients (9.0 ± 1.9 m/s) compared with both controls (7.5 ± 1.8 m/s; P = 0.018) and untreated HIV-1 patients (7.7 ± 1.3 m/s; P = 0.023), and these differences remained after adjustment for blood pressure and sex. Aortic PWV was significantly elevated (P = 0.009) in HIV-1 cART patients with MS compared to their counterparts without MS. Untreated HIV-1 patients with MS also demonstrated increased aPWV compared to their counterparts without MS (P = 0.05). Aortic AIx@HR75 was, on average, ~ 5% higher in HIV-1 cART patients with MS (28.3 ± 62% compared with untreated HIV-1 patients with MS (23.5 ± 9%; P = 0.075). Sub-group multivariate analysis identified MS as an independent predictor of increased aPWV in HIV-1 cART patients.

Conclusions

Our study established that presence of MS in HIV-1 patients on treatment was associated with increased aPWV and hence increased arterial stiffness in sub-Saharan African HIV-1 patients on first-line cART.

Left atrial functional response after a marathon in healthy amateur volunteers

Middle-aged marathon runners have an increased risk of developing atrial fibrillation (AF). A previous study described that repetitive marathon running was associated with left atrial (LA) dysfunction. However, whether this change is common in marathon runners and which runners are at risk of LA dysfunction remain unknown. The purpose of this study was to determine which factors could predict LA dysfunction. We prospectively examined 12 healthy amateur volunteers (9 males, 31 ± 8 years old) who participated in a full marathon. All echocardiographic measurements and speckle-tracking echocardiography were performed before and after the marathon. The endpoint was defined as reduced LA reservoir strain 1 day after the marathon (non-responder group). Seven participants were in the non-responder group. Age (35 ± 9 vs. 26 ± 2 years, p = 0.020), augmentation index (76 ± 12 vs. 55 ± 8, p = 0.002), and diastolic blood pressures (83 ± 11 vs. 70 ± 7 mmHg, p = 0.021) in the non-responder group were significantly higher compared with the responder group. In multivariate linear regression analysis, only the augmentation index was an independent predictor of reduced LA reservoir function after the marathon (β = - 0.646, p = 0.023). The augmentation index was a predictive marker for reduction in LA reservoir function after a marathon in healthy amateur volunteers.

Association between nondipping pattern and EndoPAT signal in patients with mild obstructive sleep apnea

OBJECTIVE

To compare vascular endothelial function between dipping (D) and nondipping (ND) patterns in patients with and without mild obstructive sleep apnea (OSA) using EndoPAT, a test of reactive hyperemia used to assess peripheral vascular endothelial function.

METHODS

The sample consisted of individuals of both genders between 18 and 65 years of age with a body mass index (BMI) of ≤35 kg/m² and apnea/hypopnea index (AHI) of ≤15. The nondipping pattern was considered present when the dip of nocturnal blood pressure (NBP) was <10%. All of the sample underwent clinical and physical evaluation, full polysomnography, 24-hour ambulatory blood pressure monitoring, and EndoPAT evaluation. A generalized linear model was used for statistical analysis.

RESULTS

The sample comprised 120 individuals, 35 in the control group and 85 in the mild OSA group. Four groups were formed: Control-ND, Control-D, Mild OSA-ND, and Mild OSA-D according to nocturnal ABPM patterns. The frequency of nondipping was (34.1%) in the Mild OSA group and (17.1%) in the Control group (p = 0.07). The Mild OSA-ND group had a higher augmentation index (AIx) than the Mild OSA-D group. Regression analysis showed that male gender, higher age, and nondipping status were associated with these results, whereas oxygen desaturation index (ODI) and AHI did not. With respect to the reactive hyperemia index (RHI), the Mild OSA-D group had lower values compared to the Control-ND group, but an association with OSA was not confirmed in the regression model.

CONCLUSION

Nondipping status was associated with a worse augmentation index in both groups independently of AHI or oxygen desaturation index. Male gender, higher age, and nondipping status were associated with augmentation index. ClinicalTrials.gov Identifier: NCT01461486.

Aortic hemodynamics in postmenopausal women following cessation of hormone therapy

Central (aortic) blood pressure and aortic pulse wave characteristics are measures of cardiovascular health, predictive of cardiovascular mortality. Previous studies have compared aortic hemodynamics in women who do and do not take menopausal hormone therapy, but characteristics of these parameters following cessation of treatment have not been defined. Therefore, the purpose of this study was to define aortic pulse wave characteristics in postmenopausal women with and without a history of menopausal hormone therapy use. Pulse wave analysis was conducted on 67 women who had participated in the randomized, double‐blind, placebo‐controlled Kronos Early Estrogen Prevention Study (KEEPS), 3 years subsequent to the four‐year treatment period. Treatment was oral conjugated equine estrogen (0.45 mg/day; n = 18); transdermal 17β‐estradiol (50 μg/day; n = 23) each with oral micronized progesterone (Prometrium 200 mg); and placebo pills and patch (n = 26). At post‐treatment, median age (60 years) and body mass index (27 kg/m²) did not differ across prior treatment assignment. Aortic blood pressures (median systolic 115 mm Hg and diastolic 76 mm Hg) and augmentation index (median 33%) did not differ among women across prior treatment assignment. These results suggest that these doses and formulations of menopausal hormone therapy had no long‐term effects on central vascular function 3 years after cessation of treatment.

Racial Disparities in Arterial Stiffness Between Healthy Whites and African Americans in the United States: A Meta-analysis

BACKGROUND

African Americans (AAs) present with cardiovascular disease (CVD) risk factors at younger ages than whites. Consequently, CVD and stroke occur at a higher incidence and at earlier decades in life in AA populations. Arterial stiffness is a predictor of CVD outcomes and partially explains the CVD risk experienced by racial minorities. We evaluated the differences in arterial stiffness observed in AAs and whites through a systematic review and meta-analysis.

METHODS

We searched PubMed and SCOPUS for comparative studies published March 1995 to November 29, 2017 comparing arterial stiffness assessments (pulse wave velocity, augmentation index, and central blood pressure) between AAs and whites. Two independent reviewers examined 195 titles/abstracts, 85 full text articles and 11 articles were included in the meta-analysis using random effects modeling approaches.

MAIN RESULTS

A total of 5060 white and 3225 AAs were included across 11 relevant studies. Carotid-femoral pulse wave velocity (cfPWV) measures were statistically different between AAs and whites (mean difference = -0.44, 95% confidence interval [CI]: -[-0.67, -0.21], p = 0.0002). Aortic femoral pulse wave velocity was significantly different between AAs and whites (mean difference = -0.21, [95% CI] -0.35, -0.07, p = 0.003) regardless of sex. Augmentation index (AIx) and Augmentation index at a 75 beats per minutes heart rate (AIx @75) was also significantly different between AA and whites (mean difference = -4.36 [95% CI] = -6.59, -2,12, p = 0.0001 and -6.26, [95% CI] = -9.19, -3.33, p < 0.0001, respectively).

CONCLUSIONS

Racial disparities in arterial stiffness persist among African American racial groups in the United States. The lack of homogeneity in studies capturing racial disparities in cfPWV suggest that additional studies are needed to understand the magnitude of racial differences in African Americans and whites that might be clinically relevant.

Gender differences of aortic wave reflection and influence of menopause on central blood pressure in patients with arterial hypertension

Background

Evidences suggest that central hemodynamics indexes are independent predictors of future cardiovascular events and all-cause mortality. Multiple factors have been pointed to have potential influence on central aortic function: height, heart rate, left ventricular ejection duration and blood pressure level. Data related to the influence of gender and postmenopausal status on aortic waveform reflection is scarce. We aim to evaluate the impact of gender and menopause on central blood pressure of hypertensive patients.

Methods

In a cross sectional study 122 hypertensive patients (52 men and 70 women) were studied. Hypertension was defined as blood pressure (BP) levels ≥140/90 mmHg or use of antihypertensive drugs. Central arterial pressure, augmentation index (AIx) and augmentation index normalized to 75 bpm (AIx75) were obtained using applanation tonometry. Menopause and postmenopause history were accessed by a direct series of questions. Postmenopause was defined as at least one year since last menstruation. Patients were paired by age, gender and menopausal status, and the data were compared considering gender and menopausal status.

Results

Height and weight were significantly lower in women than in men at the same age. Conversely, AIx (32.7 ± 9.8% vs. 20.1 ± 11.7%, p < 0.01), AIx75 (29.6 ± 6.7% vs. 18.3 ± 9.4%, p < 0.01) and central systolic blood pressure (136 ± 30 vs. 125 ± 23 mmHg, p = 0.03) were higher in women than men. The menopausal women (mean age of menopause = 48 years) had the worst indexes of aortic wave reflection, compared to men at the same age and younger women.

Conclusion

Hypertensive women had both higher reflected aortic pressure waveform and central blood pressure indexes than hypertensive men, and these findings were worsened by the menopausal status.

The effects of metformin on maternal haemodynamics in gestational diabetes mellitus: A pilot study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major clinical challenge and is likely to remain so as the incidence of GDM continues to increase.

AIM

To assess longitudinal changes in maternal haemodynamics amongst women diagnosed with GDM requiring either metformin or dietary intervention in comparison to low-risk healthy controls.

METHODOLOGY

Fifty-six pregnant women attending their first appointment at the GDM clinic and 60 low-risk healthy pregnant controls attending their routine antenatal clinics were recruited and assigned to three groups: GDM Metformin (GDM-M), GDM Diet (GDM-D) and Control. Non-invasive assessment of maternal haemodynamics, using recognised measures of arterial stiffness and central blood pressure (Arteriograph®), were undertaken under controlled conditions within four gestational windows: antenatal; AN1 (26-28 weeks), AN2 (32-34 weeks) and AN3 (37-40 weeks), and postnatal (PN) (6-8 weeks after delivery). Data were analysed using a linear mixed model incorporating gestational age and other relevant predictors, including age, blood pressure (BP), baseline bodyweight and pulse as fixed effects, and patient as a random effect.

RESULTS

Fitted linear mixed models showed evidence of a two-way interaction effect between groups (GDM-D, GDM-M and Control) and stages of gestation (AN1, AN2, AN3 and PN) for maternal haemodynamic parameters: brachial artery augmentation index (AIx) (p = 0.004), aortic AIx (p = 0.008), and central systolic BP (p = 0.001). However, differences in respect of aortic pulse wave velocity (p = 0.001) and heart rate (p < 0.001) were only significant for gestational stage. At AN2, we did not observe any evidence that the mean brachial Aix in the GDM-M was different from the control group (p = 0.158).

CONCLUSION

AIx and central systolic BP measures of arterial stiffness are adversely affected by GDM in comparison to controls during pregnancy. The possible beneficial effects of metformin therapy seen at 32 to 34 weeks of gestation require further exploration.

Reliability of oscillometric central blood pressure and central systolic loading in individuals over 50 years: Effects of posture and fasting

BACKGROUND AND AIMS

The between-day reliability of oscillometric pulse wave analysis has been demonstrated in a young, healthy population but not in an older sample. This study examined the between-day reliability of the SphygmoCor XCEL in individuals over 50 years. As blood pressure is measured in a range of postures and fasting states (supine/seated, fasted/non-fasted), this study also investigated the effect of these variables on central blood pressure and central systolic loading.

METHODS

Fifty-one adults (m = 21; age 57 ± 6.4 y) were tested on three mornings in supine and seated conditions and in fasted and non-fasted states. Data was analysed as a whole and for normotensive (n = 25) and hypertensive participants (n = 26).

RESULTS

SphygmoCor XCEL demonstrated strong reliability in the whole sample for central systolic and diastolic blood pressures, augmentation index (AIx) and AIx75 (ICC = 0.77-0.95). Significant interaction effects were observed in central diastolic blood pressure, central pulse pressure, augmentation index (AIx) and AIx75 (p < 0.05; η_p² = 0.10-0.23). Fasting state had a greater influence on central pressures in a seated than supine posture, but a greater effect on central systolic loading measures in a supine posture.

CONCLUSIONS

The SphygmoCor XCEL is a reliable tool to assess central haemodynamic variables in an older population. It would be pertinent for clinicians and researchers to record central measures in a supine posture to minimise the effects of food consumption. Conversely, the assessment of central systolic loading should occur in a seated condition to minimise the influence of varying fasting states.

Effects of 6-month treatment with the glucagon like peptide-1 analogue liraglutide on arterial stiffness, left ventricular myocardial deformation and oxidative stress in subjects with newly diagnosed type 2 diabetes

Background

Incretin-based therapies are used in the treatment of type 2 diabetes mellitus (T2DM) and obesity. We investigated the changes in arterial stiffness and left ventricular (LV) myocardial deformation after 6-month treatment with the GLP-1 analogue liraglutide in subjects with newly diagnosed T2DM.

Methods

We randomized 60 patients with newly diagnosed and treatment-naive T2DM to receive either liraglutide (n = 30) or metformin (n = 30) for 6 months. We measured at baseline and after 6-month treatment: (a) carotid-femoral pulse wave velocity (PWV) (b) LV longitudinal strain (GLS), and strain rate (GLSR), peak twisting (pTw), peak twisting velocity (pTwVel) and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography. LV untwisting was calculated as the percentage difference between peak twisting and untwisting at MVO (%dpTw–Utw_MVO), at peak (%dpTw–Utw_PEF) and end of early LV diastolic filling (%dpTw–Utw_EDF) (c) Flow mediated dilatation (FMD) of the brachial artery and percentage difference of FMD (FMD%) (d) malondialdehyde (MDA), protein carbonyls (PCs) and NT-proBNP.

Results

After 6-months treatment, subjects that received liraglutide presented with a reduced PWV (11.8 ± 2.5 vs. 10.3 ± 3.3 m/s), MDA (0.92 [0.45–2.45] vs. 0.68 [0.43–2.08] nM/L) and NT-proBNP (p < 0.05) in parallel with an increase in GLS (− 15.4 ± 3 vs. − 16.6 ± 2.7), GLSR (0.77 ± 0.2 vs. 0.89 ± 0.2), pUtwVel (− 97 ± 49 vs. − 112 ± 52°, p < 0.05), %dpTw–Utw_MVO (31 ± 10 vs. 40 ± 14), %dpTw–Utw_PEF (43 ± 19 vs. 53 ± 22) and FMD% (8.9 ± 3 vs. 13.2 ± 6, p < 0.01). There were no statistically significant differences of the measured markers in subjects that received metformin except for an improvement in FMD. In all subjects, PCs levels at baseline were negatively related to the difference of GLS (r = − 0.53) post-treatment and the difference of MDA was associated with the difference of PWV (r = 0.52) (p < 0.05 for all associations) after 6-month treatment.

Conclusions

Six-month treatment with liraglutide improves arterial stiffness, LV myocardial strain, LV twisting and untwisting and NT-proBNP by reducing oxidative stress in subjects with newly diagnosed T2DM.

ClinicalTrials.gov Identifier NCT03010683

Arterial Flow, Pulse Pressure and Pulse Wave Velocity in Men and Women at Various Ages

The increase in pulse pressure (PP) that occurs with advancing age is predominantly due to reduced arterial distensibility leading to decreased aortic compliance, particularly in the elderly, in whom high blood pressure mainly manifests as isolated systolic hypertension. Since age-related changes in stroke volume are minimal compared with changes in PP, PP is often considered a surrogate measure of arterial stiffness. However, since PP is determined by both cardiac and arterial function, a more precise and reliable means of assessment of arterial stiffness is arterial pulse wave velocity (PWV), a parameter that is only dependent on arterial properties. Arterial stiffness as measured by PWV has been found to be a powerful pressure-related indicator for cardiovascular morbidity and mortality. We analyzed PP and PWV in men and women of various age groups in healthy volunteers as well as cardiac patients with different types of diseases. The findings identified several striking sex-specific differences which demand consideration in guidelines for diagnostic procedures, for epidemiological analysis, and in evaluation of therapeutic interventions.

Impact of coronary artery disease on augmentation index as measured by estimated central blood pressure: A case control study in Asian Indians

Aims

We compared various components of blood pressure and arterial stiffness of healthy control with those of coronary artery disease (CAD) patients using BP+ machine™.

Methods

In this prospective, case-control study, total 585 individuals of both the genders were enrolled. The study population consisted of 277 controls (healthy siblings of diseased subjects not having CAD – group A) and 308 CAD patients (group B). Age and sex adjusted regression and receiver operative curve (ROC) analysis was performed to assess the strength of association of these parameters.

Results

We found that mean systolic blood pressure (SBP) (137.14 ± 22.49 vs. 129.26 ± 19.86), central systolic blood pressure (CSBP) (130.78 ± 21.89 vs. 117.53 ± 17.98), augmentation index (AI) (108.55 ± 44.98 vs. 49.38 ± 21.03) and pulse rate variability (98.82 ± 231.09 vs. 82.86 ± 208.77) were significantly (p < 0.05) higher in CAD population as compared to healthy counterparts. Left ventricular contractibility as measured by dP/dt was significantly lower in CAD patients. All these parameters were significantly abnormal in CAD as compared to healthy control population irrespective of the gender of the patient except for SBP in females. Both – odds ratio (1.108; 95% CI: 1.081–1.135; p < 0.0001) and ROC analysis (AUC: 0.937; 95% CI: 0.919–0.956; p < 0.0001) showed AI as the strongest predictor of CAD, closely followed by CSBP.

Conclusion

Central aortic blood pressure parameters such as AI and CSBP measured noninvasively with BP+ machine could be the effective predictors of CAD in Asian Indians.

Nonfunctioning adrenal incidentaloma affecting central blood pressure and arterial stiffness parameters

PURPOSE

Recently, cardiovascular risk is thought to be increased in patients with nonfunctioning adrenal incidentaloma (NFAI). There are no sufficient studies in the literature to evaluate this situation in NFAI patients without cardiovascular risk. The objective of this study is to compare peripheral and central blood pressure and arterial stiffness between patients with NFAI and healthy volunteers (of a similar age, gender and body mass index as the NFAI group) who have no traditional cardiovascular risk factors and autonomous cortisol secretion, with pulse wave analysis (PWA).

METHODS

In this cross-sectional study, we evaluated 35 NFAI patients who have no traditional cardiovascular risk factors and 35 healthy volunteers. PWA was performed in the participants of similar gender, age and body mass index, with a Mobil-O-Graph PWA/ABPM (I.E.M. GmBH, Stolberg, Germany) device. Radiological and biochemical data were obtained retrospectively in the NFAI group.

RESULTS

In our study, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), central SBP, central DBP, peripheral vascular resistance, augmentation pressure (AP), heart rate-corrected augmentation index (Aix@75) and pulse wave velocity (PWV) values were significantly higher in the NFAI group compared to the control group. In addition, peripheral and central blood pressure and arterial stiffness parameters were correlated with age and duration of NFAI diagnosis of more than 1 year.

CONCLUSIONS

NFAIs are known as cardiometabolically innocent, but in our study, both peripheral and central blood pressure values and arterial stiffness parameters were negatively affected in patients diagnosed with NFAI who have no traditional cardiovascular risk factors. These patients are at risk of cardiovascular diseases.

Relationship Between Serum Total Testosterone Concentration and Augmentation Index at Radial Artery in Japanese Postmenopausal Patients

Background

The significance of testosterone as a risk factor for cardiovascular disease (CVD) in females is controversial. This cross-sectional study aimed to elucidate the relationship between serum total testosterone concentration (T-T) and augmentation index at the radial artery (r-AIx) as a marker of arterial function in Japanese postmenopausal patients.

Methods

A total of 447 postmenopausal patients with traditional cardiovascular risk factors and/or a history of CVD (age (mean ± standard deviation (SD)), 73 ± 10 years) were enrolled. r-AIx was measured using tonometry, and the association between r-AIx and various clinical parameters, including T-T, was determined.

Results

r-AIx significantly increased (CVD vs. non-CVD: 99±11% vs. 91±11%, P < 0.001) and T-T significantly decreased (CVD vs. non-CVD: 0.31 ± 0.13 ng/mL vs. 0.49 ± 0.23 ng/mL, P < 0.001) in patients with CVD than in those without CVD. A significant negative correlation (r = -0.48; P < 0.001) between r-AIx and T-T was observed. Furthermore, multiple regression analysis indicated that T-T (t value = -7.7; P < 0.001), height (t value = -5.3; P < 0.001), d-ROMs test as a marker of oxidative stress in vivo (t value = 3.2; P < 0.001), CVD (t value = 2.9; P < 0.01), and pulse rate (t value = -2.7; P < 0.01) were independent variables for r-AIx as a subordinate factor.

Conclusion

This study revealed that low T-T is an important determining factor for an increase in r-AIx in Japanese postmenopausal patients. A prospective multicenter study with a large sample size is required to confirm the results of this study.