Brachial Systolic Blood Pressure Research Articles

Relationship between renin, aldosterone, aldosterone-to-renin ratio and left ventricular mass index in young adults

Abstract Background Primary aldosteronism (PA), characterised by excessive aldosterone production and mineralocorticoid receptor activation, is associated with adverse cardiovascular outcomes including left ventricular hypertrophy and failure. Elevated cardiovascular risk is observed even in milder and subclinical forms of PA, especially in middle-aged and elderly populations. It is unclear if early changes in PA biomarkers can affect left ventricular mass index (LVMI), which is a strong predictor of cardiovascular diseases. Aim To evaluate the relationship between PA biomarkers, namely renin concentration, aldosterone concentration and aldosterone-to-renin ratio (ARR), and LVMI in young adults. Methods The Raine Study is a longitudinal, population-based cohort study in Western Australia that enrolled women during pregnancy. We analysed the data from the offspring of these women at age 27. Participants with PA biomarkers and LVMI measured by cardiac magnetic resonance imaging were included. Females who were on oral contraception were excluded due to its confounding effect on the ARR. We examined the relationship between LVMI and plasma renin, aldosterone, and ARR using multivariate-adjusted linear regression and used mediation analysis to test whether these relationships were dependent on systolic blood pressure (SBP). Results Of 758 participants, 252 (33.2%) were females and the mean (SD) age was 26.7 (0.4) years. Females had lower median plasma renin concentration (12.0 vs 15.4mU/L; p<0.001) and higher median ARR (21.0 vs 15.6; p<0.001) than males. There was no sex-difference in median plasma aldosterone concentration (257 vs 237pmol/L in males; p=0.143). Females had lower LVMI (52.2 vs 70.2 g/m²; p<0.001) than males. A significant association between LVMI and aldosterone was detected in males (β-coefficient 0.009; 95% CI 0.001 to 0.017; p=0.027), and between LVMI and ARR in females (β-coefficient 0.098; 95% CI 0.001 to 0.196; p=0.050) after adjusting for confounders. This relationship was not mediated by brachial SBP. Conclusion An elevated aldosterone concentration or ARR was associated with higher LVMI in young adults, independent of brachial SBP. Long-term follow-up is required to determine if the relationship persists over time and leads to reduced cardiac function. One may speculate that an intervention trial in young adults with subclinical PA is warranted to determine the role of aldosterone blockade in preventing future cardiovascular diseases.

Patients vaccinated against COVID-19 present better coronary flow, myocardial work and NTproNP levels than non-vaccinated at 4 months post COVID infection

Abstract Introduction COVID-19 affected patients present impaired subclinical markers of cardiovascular and endothelial function post resolution of infection. Whether vaccination impedes impairment of myocardial and vascular function has not been clarified. Purpose We investigated the effect of COVID-19 infection on markers of endothelial, vascular and myocardial function in vaccinated and non-vaccinated subjects at four months after the infection. Methods We recruited 60 vaccinated and 60 non-vaccinated patients with similar clinical characteristics, who were examined in a dedicated post-COVID-19 outpatient clinic during a scheduled follow-up visit at four months after a confirmed COVID-19 infection. We measured (i) perfused boundary region (PBR) of the sublingual arterial (increased PBR indicates reduced endothelial glycocalyx thickness), (ii) flow-mediated dilatation (FMD), (iii) coronary flow reserve (CFR) by Doppler echocardiography, (iv) pulse wave velocity (PWV) and central systolic blood pressure (cSBP), (v) global left and right ventricular longitudinal strain (GLS), (vi) myocardial global work index (GWI) global constructive work (GCW), global wasted work (GWW) and the myocardial global work efficiency (GWE) and v) NTproBNP blood levels. Results Among vaccinated patients 54,2% had mild disease, 33,3% had moderate disease and 12,5% had severe disease, while among non-vaccinated 29,1% had mild disease, 32,9% had moderate disease and 38% had severe disease(p<0.05). At four months, vaccinated patients presented with higher LVGLS, GCW values and CFR compared to non-vaccinated (p>0.05 table), while GWI, GWW and GWE were similar between the two groups(p>0.5). Moreover, in vaccinated patients RVGLS and RV FWLS were significantly higher than in non-vaccinated patients (p>0.05). Also, NTproBNP leves were significantly lower in vaccinated than in non-vaccinated patients (p<0.05). At four months, in vaccinated patients , we observed a marginally lower brachial and central systolic blood pressure compared with non-vaccinated (p=0.045, p=0.048 respectively.) Vaccinated patients displayed similar FMD and PWV values compared to non-vaccinated (p>0.05 for all the comparisons). Conclusion Patients vaccinated against COVID-19 suffered from milder disease resulting to better cardiac function and lower NTproNP levels than non-vaccinated 4 months post COVID infection.

The use of a novel toe-thumb pressure index for assessing arterial status in the lower limb. A reliability and validity study.

This study explored the reliability, validity and perceived comfort of a novel thumb pressure measure and calculation of a toe-thumb index to identify their suitability as an adjunct or alternatives to ankle-brachial and toe-brachial indices. Repeated manual thumb and toe systolic blood pressures were conducted using two raters, over two time points, on 34 healthy participants. Concurrent automated toe, thumb and brachial systolic blood pressures as well as comfort ratings for these measures (using a 10mm visual analogue scale) were captured once by a research assistant. Automated thumb and brachial measures showed fair correlation (ρ=0.36, p=0.03) and a toe-thumb index and toe-brachial index good correlation (ρ=0.62, p<0.01). Intraclass correlation coefficients (ICC) identified moderate intra-rater reliability for manual thumb pressures for Rater 1 and 2 (ICC 0.57, 95% CI [0.14, 0.79] and ICC 0.74, 95% CI [0.49, 0.87], respectively), while inter-rater reliability was poor (ICC=0.16, 95% CI [-0.85, 0.47]). Concurrent validity comparing manual and automated measures for thumb pressure was also poor (ICC -0.05, 95% CI [-1.06, 0.72] and ICC 0.42, 95% CI [-0.16, 0.72] Rater 1 and 2 respectively). Thumb measures were significantly more comfortable than brachial measures (5mm, p<0.00). Thumb systolic pressures are correlated with brachial systolic pressures, with reasonable intra-rater reliability, however, correlation is only fair and measurement error wider than clinically acceptable. Furthermore, manual measures are poorly correlated with automated units. Consequently, caution is required in applying these techniques. As thumb measures were perceived as significantly more comfortable than brachial measures and have an advantage where brachial pressures cannot, or should not, be obtained, further evaluation is warranted.

Intrarater Reliability and Agreement of Blood Pressure, Arterial Stiffness, and Heart Rate Variability Assessments in Patients With Parkinson's Disease.

To assess the intrarater reliability and agreement of blood pressure (BP), arterial stiffness, and heart rate variability (HRV) assessments in patients with Parkinson`s disease (PD). Twenty patients with PD visited the laboratory three times, during which brachial and central BP (auscultatory and applanation tonometry, respectively), arterial stiffness (carotid-femoral pulse wave velocity and augmentation index), and HRV assessments were performed at rest. Brachial and central systolic BP presented greater values on visit 1 when compared to visits 2 and 3 (122±13 vs. 116±16 vs. 120±15, p=0.029). There were no significant differences (p>0.05) among the experimental visits for other parameters. Brachial and central BP showed an intraclass correlation coefficient (ICC) above 0.842 and a standard error of measurement (SEM) lower than 5.0%. Bland-Altman plots indicated low agreement between visits 1 and 2 and good agreement between visits 2 and 3. Arterial stiffness indices exhibited ICC values between 0.781 and 0.886, and SEM ranged from 7.3% to 25.2%. Bland-Altman plots indicated moderate to good agreement among visits for arterial stiffness parameters. HRV indices presented ICC values ranging from 0.558 to 0.854 and SEM values ranging from 5.1% to 76.0%. Bland-Altman plots indicated moderate agreement among visits for HRV parameters. In PD patients, brachial and central BP present low intrarater reliability and agreement between visits 1 and 2 and good intrarater reliability and agreement between visits 2 and 3. In general, arterial stiffness and HRV assessments present acceptable intrarater reliability and agreement among visits, except for cardiac sympathovagal balance.

Cruciferous vegetables lower blood pressure in adults with mildly elevated blood pressure in a randomized, controlled, crossover trial: the VEgetableS for vaScular hEaLth (VESSEL) study

BackgroundHigher cruciferous vegetable intake is associated with lower cardiovascular disease risk in observational studies. The pathways involved remain uncertain. We aimed to determine whether cruciferous vegetable intake (active) lowers 24-h brachial systolic blood pressure (SBP; primary outcome) compared to root and squash vegetables (control) in Australian adults with mildly elevated BP (SBP 120–160 mmHg inclusive).MethodsIn this randomized, controlled, crossover trial, participants completed two 2-week dietary interventions separated by a 2-week washout. Cruciferous vegetables were compared to root and squash vegetables (~ 300 g/day) consumed with lunch and dinner meals. Participants were blinded to which interventions were the active and control. Adherence was assessed using food diaries and biomarkers (S-methyl cysteine sulfoxide (SMCSO, active) and carotenoids (control)). Twenty-four-hour brachial ambulatory SBP and secondary outcomes were assessed pre- and post each intervention. Differences were tested using linear mixed effects regression.ResultsEighteen participants were recruited (median (IQR) age: 68 (66–70); female: n = 16/18; mean ± SD clinic SBP: 135.9 ± 10.0 mmHg). For both interventions, 72% participants had 100% adherence (IQR: 96.4–100%). SMCSO and carotenoids were significantly different between interventions (mean difference active vs. control SMCSO: 22.93 mg/mL, 95%CI 15.62, 30.23, P < 0.0001; carotenoids: − 0.974 mg/mL, 95%CI − 1.525, − 0.423, P = 0.001). Twenty-four-hour brachial SBP was significantly reduced following the active vs. control (mean difference − 2.5 mmHg, 95%CI − 4.2, − 0.9, P = 0.002; active pre: 126.8 ± 12.6 mmHg, post: 124.4 ± 11.8 mmHg; control pre: 125.5 ± 12.1 mmHg, post: 124.8 ± 13.1 mmHg, n = 17), driven by daytime SBP (mean difference − 3.6 mmHg, 95%CI − 5.4, − 1.7, P < 0.001). Serum triglycerides were significantly lower following the active vs. control (mean difference − 0.2 mmol/L, 95%CI − 0.4, − 0.0, P = 0.047).ConclusionsIncreased intake of cruciferous vegetables resulted in reduced SBP compared to root and squash vegetables. Future research is needed to determine whether targeted recommendations for increasing cruciferous vegetable intake benefits population health.Trial registrationClinical trial registry ACTRN12619001294145. https://www.anzctr.org.au

O99 RELATIONSHIP BETWEEN RENIN, ALDOSTERONE, ALDOSTERONE-TO-RENIN RATIO AND LEFT VENTRICULAR MASS INDEX IN YOUNG ADULTS

Background and Objective: Primary aldosteronism (PA), characterised by excessive aldosterone production and mineralocorticoid receptor activation, is associated with adverse cardiovascular outcomes including left ventricular hypertrophy and failure. Elevated cardiovascular risk is observed even in milder and subclinical forms of PA, based on studies primarily conducted in middle-aged and elderly populations. It is unclear if the biomarkers of PA, including renin, aldosterone, and aldosterone-to-renin ratio (ARR), are associated with left ventricular mass index (LVMI), which is a strong predictor of cardiovascular diseases, in young adults. Methods: The Raine Study is a longitudinal, population-based cohort study in Western Australia that enrolled women during pregnancy. We analysed the data from the offspring of these women at age 27 years. Participants with elevated high-sensitivity C-reactive protein (&gt;10 mg/L) and females who were on oral contraception were excluded. LVMI was measured by cardiac magnetic resonance imaging. We examined the relationship between LVMI and plasma renin, aldosterone, and ARR using multivariate-adjusted linear regression and used mediation analysis to test whether these relationships were dependent on systolic blood pressure (SBP). Results: Of 758 participants, 252 (33.2%) were females. Females had lower median plasma renin concentration (12.0 vs 15.4mU/L; p&lt;0.001) and higher median ARR (21.0 vs 15.6; p&lt;0.001) than males. There was no sex-difference in median plasma aldosterone concentration (257 vs 237pmol/L in males; p=0.143). Females had lower LVMI (52.2 vs 70.2 g/m2; p&lt;0.001) than males. A significant association between LVMI and aldosterone was detected in males (β-coefficient 0.009; 95% CI 0.001 to 0.017; p=0.027), and between LVMI and ARR in females (β-coefficient 0.098; 95% CI 0.001 to 0.196; p=0.050) after adjusting for confounders. This relationship was not mediated by brachial SBP. Conclusions: An elevated aldosterone concentration or ARR was associated with higher LVMI in young adults, independent of brachial SBP. Long-term follow-up is required to determine if the relationship persists over time and leads to reduced cardiac function.

Abstract 56: High Blood Pressure Is Associated with Lower Brain Volume and Cortical Thickness in Healthy Young Adults

Background: High blood pressure (BP) in middle-aged and older adults is associated with lower brain volume and cortical thickness assessed with structural MRI. However, little evidence is available in young adults. Objective: We investigated the associations of high BP with brain volumes and cortical thickness in healthy young adults. We hypothesized that high BP is associated with lower brain volume and cortical thickness in young adults. Methods: This cross-sectional study included 1095 young adults (54% women, 22-37 years) from the Human Connectome Project (HCP) who self-reported not having a history of hypertension or taking antihypertensive medications. Brachial systolic (SBP) and diastolic BP (DBP) were measured with semi-automatic or manual sphygmomanometer during study visits. Structural MRI was used to measure gray matter (GM) and white matter (WM) volume and mean cortical thickness. Associations of BP and hypertension stage with total and regional brain volumes and cortical thickness were analyzed using linear regression and analysis of covariance (ANCOVA) after adjusting for age, sex, education years, body mass index (BMI), smoking, alcohol consumption history, zygosity, and total intracranial volume. Results: SBP and DBP were (mean ± SD) 123.6 ± 14.2 and 76.5 ± 10.6 mmHg, respectively (n = 1095). High DBP was associated with lower total GM ( p = 0.012), cortical GM ( p = 0.004), subcortical GM ( p = 0.012), and total WM volumes ( p = 0.031). There were no associations of SBP and hypertension stage with total brain volume and cortical thickness. High SBP and DBP were associated with lower regional cortical thickness in the parietal lobe and lingual gyrus, and lower regional cortical volume in the postcentral gyrus, inferior parietal lobe, lateral occipital gyrus, and middle temporal gyrus. Conclusion: Associations of high BP, particularly DBP, with lower total and regional brain volume and cortical thickness were observed in healthy young adults. These findings suggest the importance of prevention or control of high BP early in life for brain health.

Abstract MP27: Pregnant Women of Advanced Maternal Age Have Higher Central Artery Stiffness Than Younger Pregnant Women

The frequency of women undergoing pregnancy at advanced maternal age (AMA, ≥35 years) is increasing in developed countries, including the United States. AMA is associated with an increased risk of adverse pregnancy outcomes such as gestational hypertension, preeclampsia, and preterm birth. Increased risk for adverse pregnancy outcomes at AMA may be mediated in part by altered arterial structure and function or inadequate maternal arterial adaptations during pregnancy. Therefore, we examined central artery stiffness and endothelial function across healthy pregnancy (i.e. no comorbid maternal or fetal conditions, born at term) in women who had enrolled in a longitudinal study between March 2015 and January 2020. We hypothesized that women at AMA (age ≥35 years, mean±SE: 36±0 years, n=18) would have higher arterial stiffness and lower endothelial function compared with younger women (age 21-30 years, mean±SE: 27±0 years, n=51) across pregnancy. Hemodynamic and arterial function measures were collected in the first (6-13 weeks), second (18-26 weeks), and third (27-37 weeks) trimesters and postpartum (4-14 weeks after the delivery). Brachial artery blood pressure was assessed in the supine position and central artery stiffness was assessed via carotid-femoral (aortic) pulse wave velocity (cfPWV) and carotid β-stiffness index. Endothelial function was determined via brachial artery flow-mediated dilation (FMD). Brachial artery systolic, diastolic, and mean blood pressures were not different between AMA and younger women across pregnancy or postpartum (all P &gt;0.05). The AMA group had higher cfPWV ( P &lt;0.01) and carotid β-stiffness index ( P &lt;0.01) across pregnancy and postpartum compared to the younger group. cfPWV decreased among younger women at the second and third trimesters compared with the first trimester ( P &lt;0.01), while cfPWV among women of AMA did not change ( P =0.07). There were no differences in FMD between AMA and younger women across pregnancy or postpartum ( P =0.96). These results demonstrate that healthy women of AMA have increased central artery stiffness, but no difference in endothelial function, compared to younger pregnant women across pregnancy, and that the normal decrease in aortic stiffness is blunted in pregnant women of AMA compared to younger women. The sustained higher central artery stiffness throughout pregnancy among women of AMA may contribute to increased risk of pregnancy complications and future CVD risk in these women.

Associations between physical activity and ankle-brachial index: the Swedish CArdioPulmonary bioImage Study (SCAPIS)

BackgroundThe ankle–brachial index (ABI) is the ratio of the ankle and brachial systolic blood pressures. In the clinical setting, low ABI (< 0.9) is an indicator of peripheral atherosclerosis, while high ABI (> 1.4) is a sign of arterial stiffness and calcification. The purpose of the current study was to investigate the association between ABI and physical activity levels, measured by accelerometer.MethodsThe Swedish CArdioPulmonary bioImage Study (SCAPIS) is a Swedish nationwide population-based cross-sectional cohort for the study of cardiovascular and pulmonary diseases, in which individuals aged 50–64 years were randomly invited from the general population. The study population with data on ABI, physical activity, and sedentary time based on accelerometry was 27,737. Differences between ABI categories and associations to sedentary behavior, moderate to vigorous physical activity (MVPA), and other metabolic characteristics were compared. ABI was categorized as low, ABI ≤ 0.9, borderline, ABI 0.91–0.99, normal, ABI 1.0-1.39, and high, ABI ≥ 1.4.ResultsPrevalence of low ABI was higher in the most sedentary quartiles compared to the least sedentary (0.6% vs. 0.1%, p < 0.001). The most sedentary individuals also exhibited higher BMI, higher prevalence of diabetes and hypertension. The proportion of wake time spent in MVPA was lowest in those with low ABI (0.033 ± 0.004; p < 0.001) and highest in those with ABI > 1.4 (0.069 ± 0.001; p < 0.001) compared to those with normal ABI. Compared to normal ABI, the proportion of sedentary time was highest in those with low ABI (0.597 ± 0.012; p < 0.001) and lowest in those with ABI > 1.4 (0.534 ± 0.002; p = 0.004).ConclusionThis population-based study shows that middle-aged individuals with ABI > 1.4 have the highest level of physical activity, while individuals with a lower ABI, especially those with ABI < 0.9, are less active and spend more time sedentary. Future studies are needed to understand the relationships between ABI, physical activity, and the risk of peripheral arterial and cardiovascular disease in the general population.

Associations of 24-Hour Central Systolic Blood Pressure With Multiorgan Damage in Nondialysis Patients With Chronic Kidney Disease.

Multiple target-organ damages (TODs) in the same patient are common and further increase the risk of cardiovascular disease. However, the relationship between ambulatory central systolic blood pressure (SBP) and multiple TODs has yet to be explored. MobilO-Graph PWA was used to monitor the participants' ambulatory blood pressure, and the presence of left ventricular hypertrophy, carotid hypertrophy, and kidney injury were used to define TOD. Logistic regression analyses and receiver operating characteristic analyses were used to explore the correlation between SBP and TOD. Overall, 2018 nondialysis patients with chronic kidney disease were included and 580 (28.74%) had multiple TODs. Twenty-four-hour central SBP with c2 calibration exhibited a stronger correlation with the increasing number of TOD compared with 24-hour brachial SBP in ordinal logistic regression analyses. In the multivariable analyses with the presence of multiple TODs, the odds ratios were 1.786 (95% CI, 1.474-2.165; P<0.001) for 24-hour brachial SBP and 1.949 (95% CI, 1.605-2.366; P<0.001) for 24-hour central SBP with c2 calibration. The receiver operating characteristic analyses also showed that 24-hour central SBP with c2 calibration had higher discrimination than 24-hour brachial SBP regarding multiple TODs (P<0.001). In addition, using 130/135 mm Hg as the threshold for 24-hour brachial SBP/central SBP with c2 calibration to cross-classify, the prevalence of multiple TODs was greater in cases of concordant hypertension compared with cases of isolated brachial hypertension and concordant normotension, with no difference between the latter 2 conditions. Twenty-four-hour central SBP with c2 calibration was more associated with the presence of multiple TODs compared with 24-hour brachial SBP and was helpful in risk classification of multiple TODs among nondialysis patients with chronic kidney disease.

Short-Term Variability of Both Brachial and Aortic Blood Pressure is Increased in Patients with Immune-mediated Chronic Inflammation.

Blood pressure (BP) variability (BPV) has emerged as an indicator of subclinical organ damage and an independent predictor of cardiovascular disease (CVD) morbidity and mortality in high-risk populations. We aimed to assess short-term variability of both brachial and aortic BP in psoriasis, a common immune-mediated inflammatory disorder characterized by increased CVD risk. Psoriasis patients and non-psoriasis individuals had their BP assessed throughout a 24h period (Mobil-O-Graph device). Brachial and aortic BPV during the 24h and the respective daytime and nighttime periods was calculated from relevant ambulatory BP profiles. In-house software was applied to automatically calculate average real variability (ARV) of brachial and aortic systolic (bSBP, aSBP) and diastolic BP (bDPB, aDBP), and the weighted standard deviation (wSD) of 24h bSBP/aSBP. 24h pulse wave velocity (PWV) and augmentation index (AIx) were used as widely applied markers of arterial stiffness. Psoriasis patients (n = 74) presented increased ARV of 24h and daytime bSBP/aSBP, and increased ARV of 24h and daytime bDBP/aDBP, compared to controls (n = 40). PWV and AIx correlated with ARV of 24h bSBP/aSBP, daytime bSBP/aSBP, while PWV further correlated with ARV of nighttime aSBP. The observed associations with PWV, yet not AIx, with indices of BPV remained significant after adjusting for CVD risk factors. This is the first study reporting increased 24h variability of both brachial and aortic BP in psoriasis. The association of short-term BPV with arterial stiffness implies a potential role of BPV in terms of CVD risk stratification in patients with chronic immune-mediated inflammation.

Aortic Stiffness Is Associated With Higher Nighttime Ambulatory Blood Pressure in Middle-Aged and Older Adults.

The objective of this study was to determine the relationship between aortic stiffening and brachial and central ambulatory blood pressure (AMBP) in a nonclinical sample of middle-aged and older adults (MA/O). We hypothesized aortic stiffness would be positively associated with 24-hr, daytime, and nighttime brachial and central AMBP. Fifty-one participants aged ≥50yr (21 males and 30 females, mean age 63.4±9.0yr) with a body mass index <35 kg/m 2 who also had a resting brachial blood pressure (BP) <160/100mmHg with or without BP medications were recruited for this cross-sectional analysis. All participants underwent measures of aortic stiffness (carotid-femoral pulse wave velocity [cfPWV]) and 24-hr AMBP monitoring. Bivariate correlations assessed the relationship between cfPWV, brachial, and central AMBP. Partial correlations were used to independently adjust for traditional cardiovascular disease (CVD) risk factors including age, sex, waist circumference, glucose, and augmentation index normalized to heart rate 75bpm, a surrogate measure of arterial stiffness, and in a multivariable combined model. Nighttime brachial systolic BP ( r =0.31) and central systolic BP ( r =0.30) were correlated with cfPWV in the multivariable combined model ( P ≤.05). Nighttime brachial pulse pressure and central pulse pressure were correlated with cfPWV after independently adjusting for all CVD risk factors ( P ≤.05, all) but not when combined in the multivariable model ( P >.05). Higher nighttime brachial and central AMBP with older age are related, in part, to greater aortic stiffening. Therefore, interventions to lower or prevent aortic stiffening may also lower nighttime BP in MA/O adults to lower CVD risk.

High Blood Pressure Is Associated With Lower Brain Volume and Cortical Thickness in Healthy Young Adults.

High blood pressure (BP) in middle-aged and older adults is associated with lower brain volume and cortical thickness assessed with structural magnetic resonance imaging (MRI). However, little evidence is available on young adults. We investigated the associations of high BP with brain volumes and cortical thickness in healthy young adults. This cross-sectional study included 1,095 young adults (54% women, 22-37 years) from the Human Connectome Project (HCP) who self-reported not having a history of hypertension or taking antihypertensive medications. Brachial systolic (SBP) and diastolic BP (DBP) were measured with a semi-automatic or manual sphygmomanometer during study visits. Structural MRI was used to measure gray matter (GM) and white matter (WM) volume and mean cortical thickness. Associations of BP and hypertension stage with total and regional brain volumes and cortical thickness were analyzed using linear regression and analysis of covariance (ANCOVA) after adjusting for age, sex, education years, body mass index (BMI), smoking, alcohol consumption history, zygosity, and total intracranial volume. SBP and DBP were (mean ± SD) 123.6 ± 14.2 and 76.5 ± 10.6 mm Hg, respectively, (n = 1,095). High DBP was associated with lower total GM (P = 0.012), cortical GM (P = 0.004), subcortical GM (P = 0.012), and total WM volumes (P = 0.031). High SBP and DBP were associated with lower regional cortical volume and cortical thickness. These findings suggest that high BP may have deleterious effects on brain health at the early stage of adulthood.

Age and Sex Differences in the Contribution of Mean Arterial Pressure to Pulse Pressure Before Middle Age.

A lower ability to buffer pulse pressure (PP) in the face of increasing mean arterial pressure (MAP) may underlie the disproportionate increase in systolic blood pressure (SBP) in women from young adulthood through middle-aged relative to men. To evaluate the contribution of MAP to the change in PP and pressure wave contour in men and women from young adulthood to middle age. Central pressure waveform was obtained from radial artery applanation tonometry in 312 hypertensive patients between 16 to 49 years (134 women, mean age 35 ± 9 years), 185 of whom were on antihypertensive treatment. Higher MAP levels (≥ 100 mmHg) were significantly associated with higher brachial and central SBP (P < 0.001), PP (P < 0.001), incident wave (P = 0.005), AP (P < 0.001), and PWV (P < 0.001) compared to lower MAP levels. The relationship between MAP and brachial PP (P < 0.001), central PP (P < 0.001), incident wave (P < 0.001), and AP (P < 0.01), but not PWV, strengthens with age. The age-related increase in the contribution of MAP to brachial PP (P < 0.001), central PP (P < 0.001), and incident wave (P < 0.001) was more prominent in women than in men beginning in the fourth decade. In multiple regression analyses, MAP remained a significantly stronger predictor of central PP and incident wave in women than in men, independent of age, heart rate, and antihypertensive treatment. In turn, age remained a significantly stronger predictor of central PP and incident wave in women than in men, independent of MAP, heart rate, and antihypertensive treatment. Women of reproductive age showed a steeper increase in PP with increasing MAP, despite comparable increases in arterial stiffness in both sexes. The difference was driven by a greater contribution of MAP to the forward component of the pressure wave in women.

Relationship between baroreflex sensitivity and orthostatic blood pressure increases in humans

Background: Orthostatic hypertension (OHT) is characterized by an increase in blood pressure (BP) upon standing. Although not a common condition, it is not considered rare. Autonomic dysfunction has been speculated to be a potential cause of OHT as the baroreflex is essential for maintaining homeostasis. However, the exact mechanism responsible for OHT remains unclear. Additionally, the definition of OHT varied among prior reports, and diagnostic criteria have not been firmly established. Thus, this study aims to assess differences in autonomic function in the supine and standing positions in individuals with and without elevated BP upon standing. Hypothesis: Individuals with elevated BP upon standing will have lower cardiovagal baroreflex sensitivity (CBRS) than individuals without elevated BP upon standing. Methods: This study included 90 healthy volunteers (39 ± 14 years; 21 men and 69 women). Brachial BP was measured with a cuff on an upper arm. Beat-by-beat BP with a Finometer and heart rate (HR) with ECG were measured during 10 minutes of supine rest and 10 minutes of standing. Spontaneous CBRS was calculated from the relationship between systolic BP (SBP) and R-R intervals using the sequence method. Heart rate variability (HRV) indices were also calculated. Results: Subjects were sorted into four groups based on the change in brachial SBP upon standing: Control (-5 &lt; ΔSBP &lt; 10 mmHg, n = 53), Mild (10 ≤ ΔSBP &lt; 15 mmHg, n = 22), Moderate (15 ≤ ΔSBP &lt; 20 mmHg, n = 8), and Severe (ΔSBP ≥ 20 mmHg, n = 7). There were no significant differences in age, body mass index, or sex ratio among groups (all P &gt; 0.05). Supine CBRS was significantly lower in the Severe group than in the Control group (9.8 ± 4.1 vs. 16.9 ± 9.0 ms/mmHg, P = 0.003) and the other two groups (all P &lt; 0.05). Additionally, ΔSBP was negatively correlated with supine CBRS in subjects with ΔSBP ≥ 10 mmHg (R = -0.39, P = 0.02, n = 37). Supine high-frequency (HF) power of HRV, an index of vagal activity, was also significantly lower in the Severe group than in the Control group (493 ± 503 vs. 1561 ± 2277 ms2, P = 0.006). Standing induced significant decreases in CBRS and HF power in all groups (all P &lt; 0.05). During standing, CBRS remained significantly lower in the Severe group than in the Control group (P = 0.045), but no other significant differences were observed in CBRS or HRV indices between the groups. Discussion and Conclusion: OHT is associated with adverse cardiovascular events. Our data show that supine baroreflex sensitivity and vagal tone are lower in individuals with higher (ΔSBP ≥ 20 mmHg) elevated BP upon standing. Additionally, a negative relationship was observed between CBRS and elevated SBP (ΔSBP ≥ 10 mmHg) upon standing. These findings suggest that altered or impaired autonomic function may contribute to OHT. In addition, the data support the recent consensus definition of clinical OHT (ΔSBP ≥ 20 mmHg). Further studies are warranted to examine the mechanisms in more detail. This study was supported by NIH R01 HL144781 and R01 HL141198. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Age Comparisons of Cardiac Work During Exercise in Women: Insight from Acute β1 Adrenergic Blockade

Postmenopausal women exhibit exaggerated increases in blood pressure during activities of daily living and exercise. The decreased size and increased stiffening of postmenopausal women's hearts elevate myocardial oxygen demand when compared to age-matched men and younger cohorts. Together, this poses a risk to the safety of, and capacity for, exercise in postmenopausal women. We recently studied the effects of esmolol, a fast-acting, cardio-selective β1 antagonist, on oxygen transport variables during dynamic exercise in healthy young (Y) and older (O) women to better understand differences in cardiovascular responses to exercise. Objective: Determine the effects of acute cardiac specific blockade on myocardial oxygen demand (rate pressure product, RPP) and cardiac work (CW) in healthy young premenopausal and older postmenopausal women. Methods: Thirteen healthy young (20-32 yr) and older postmenopausal (58-70 yr) women performed moderate (85% of lactate threshold) and heavy (50% between lactate threshold and the respiratory compensation point) recumbent leg cycling exercise during IV infusion of saline or esmolol in randomized order. Whole body oxygen consumption (VO2, indirect calorimetry), brachial systolic blood pressure (SBP, automated cuff), heart rate (HR, ECG), and cardiac output (CO, bioimpedance) were measured continuously. RPP (HR×SBP), CW (CO×SBP), and cardiac effciency (CE, CW/VO2) were calculated. Mixed model repeated measures ANOVAs were used to determine the effect of treatment and age group. Results: Power outputs were lower in O vs. Y at both moderate (45±9W and 72±15W, p&lt;0.001) and heavy (81±21W vs. 117±32W, p&lt;0.001) intensities. During the saline trial CO was lower (p&lt;0.001), and RPP was higher (p&lt;0.001) in the O vs. Y group during both intensities. There was a main effect of treatment on RPP, CW, and CE. Esmolol reduced RPP (4638±775 SD, p&lt;0.001), CW (547±89, p&lt;0.001) and CE (1682±62, p&lt;0.001) in both O and Y. There was a main effect of age group on CE, pairwise comparisons showed CE was lower in O than Y (441±112, p&lt;0.001). Conclusions: Older postmenopausal women experience higher myocardial oxygen demand and perform more cardiac work for a given whole body liter oxygen consumed during dynamic leg exercise compared to younger premenopausal women. Acute β1 adrenergic blockade narrows the gap between central cardiovascular function in young and old women and provides a powerful tool to investigate age-related cardiovascular differences. NIH R21 AG054940. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sex Differences in Central Hemodynamics of Patients with Untreated Obstructive Sleep Apnea

Patients with obstructive sleep apnea (OSA) have increased risk for cardiovascular diseases. Data from the Atherosclerosis Risk in the Communities and Sleep Heart Health Study suggest that OSA is more deleterious to females versus males, although mechanistic data are lacking. Estimates of central (aortic) blood pressure (BP) are superior in predicting future cardiovascular events than traditional brachial BP measurements. While patients with OSA have altered central hemodynamics (e.g., higher aortic pulse wave velocity; PWV), potential sex differences are unexplored. We tested the hypothesis that females with OSA (n=7, 50±3yrs, 35.1±1.9kg/m2, 22.2±7.6 events/hr) have worse central hemodynamics than males with OSA (n=9, 47±3yrs, 35.0±1.4kg/m2, 31.7±6.2 events/hr). Data collection consisted of an overnight sleep study (polysomnography) to identify the presence, and characterize the severity, of OSA via the apnea-hypopnea index (AHI). Then, duplicate measures of central (aortic) and peripheral (brachial) BP, as well as central artery stiffness (PWV) and wave reflection (AIx), were made in the morning after ≥15min of quiet, supine rest. Additional hemodynamic measurements were made if data differed by ≥2% (AIx) or ≥0.5m/s (PWV). Data that met these criteria were averaged and used for analysis. Comparisons were made using two-tailed, independent samples t-tests or nonparametric Mann-Whitney Rank Sum tests, as indicated. No differences were observed in age (p=0.44), body mass index (p=0.96), nor AHI (p=1.00) between sexes. Similarly, no sex differences were observed in brachial systolic (female vs. male: 129±7 vs. 134±8mmHg, p=0.83), diastolic (77±5 vs. 85±4mmHg, p=0.26), or mean BP (96±6 vs. 101±5mmHg, p=0.45). Similarly, central systolic (122±6 vs. 125±7mmHg, p=0.96), diastolic (78±5 vs. 86±4mmHg, p=0.25), and augmentation (21±2 vs. 15±2mmHg, p=0.07) BP did not differ between sexes. Resting heart rate was also comparable between groups (67±3 vs. 65±2bpm, p=0.64). However, AIx (AIx; 42±3 vs. 35±4%) and AIx normalized to a heart rate of 75bpm (42±3 vs. 30±3%) were higher in females with OSA relative to males with OSA (p&lt;0.05 for both). Interestingly, the forward (30±3 vs. 28±2mmHg, p=0.63) and reflected (20±2 vs. 18±2mmHg, p=0.44) pulse heights, as well as PWV (7.3±0.6 vs. 7.4±0.6m/s, p=0.85), were similar between groups. Our data indicate that despite a trend towards higher BP in males with OSA (~5mmHg) that may be clinically, though not statistically different, females with OSA have a higher AIx. As AIx is positively associated with left ventricular hypertrophy, these data also suggest that altered central (aortic) hemodynamics may contribute to the sex differences in cardiovascular risk with OSA. This work was supported by the National Institutes of Health T32-HL007111 and U54AG044170 (JMB), HL065176 (PS and VKS), and HL134885 (VKS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Differences between brachial and aortic blood pressure in adolescence and their implications for diagnosis of hypertension.

Blood pressure (BP) is the leading global cause of mortality, and its prevalence is increasing in children and adolescents. Aortic BP is lower than brachial BP in adults. We aimed to assess the extent of this difference and its impact on the diagnosis of hypertension among adolescents. We used data from 3850 participants from a UK cohort of births in the early 1990s in the Southwest of England, who attended their ∼17-year follow-up and had valid measures of brachial and aortic BP at that clinic [mean (SD) age 17.8 (0.4) years, 66% female individuals]. Data are presented as mean differences [95% prediction intervals] for both sexes. Aortic systolic BP (SBP) was lower than brachial SBP [male, -22.3 (-31.2, -13.3) mmHg; female, -17.8 (-25.5, -10.0) mmHg]. Differences between aortic and brachial diastolic BP (DBP) were minimal. Based on brachial BP measurements, 101 male individuals (6%) and 22 female individuals (1%) were classified as hypertensive. In contrast, only nine male individuals (<1%) and 14 female individuals (<1%) met the criteria for hypertension based on aortic BP, and the predictive value of brachial BP for aortic hypertension was poor (positive-predictive value = 13.8%). Participants with aortic hypertension had a higher left ventricular mass index than those with brachial hypertension. Brachial BP substantially overestimates aortic BP in adolescents because of marked aortic-to-brachial pulse pressure amplification. The use of brachial BP measurement may result in an overdiagnosis of hypertension during screening in adolescence.

A Practical Approach for Ischemic Preconditioning Intervention in Sports: A Pilot Study for Cuff Thigh Occlusion Pressure Estimation Based on Systolic Blood Pressure.

For the ischemic preconditioning (IPC) intervention, the accuracy of the protocol is paramount for mediating its possible ergogenic effects. However, the lack of standardization and widespread use of arbitrary cuff pressures (ranging from 130 to >300 mmHg) have been predominantly observed, potentially affecting the results and compromising the reproducibility of findings. Thus, the purpose of this study was to determine an appropriate cuff pressure during IPC. Seventeen healthy male participants were enrolled in the study. Anthropometric measurements were initially conducted, followed by systolic and diastolic blood pressure measurements. Subsequently, we determined the individual thigh occlusion pressure (TOP) for the right leg using a hand-held Doppler device. Based on these findings, we developed an estimation equation for TOP, considering the current brachial systolic blood pressure (SBP) values. We then conducted a retrospective analysis of its capacity to mediate occlusion. We observed the ability to estimate TOP using the equation (p = 0.01; ES: 0.86), presenting ~6% superiority in absolute values for occlusion compared to direct measurement (TOP equation: 169.9 ± 9.1; TOP direct measured: 161.2 ± 11.1). However, TOP estimation was insufficient to produce complete occlusion in two out of 17 subjects (11.8%). In conclusion, the estimation of TOP incorporating SBP values may offer a valid and practical means for cuff administration during IPC protocols with potential to minimize adverse effects and maximize its positive effects.

Endothelial dysfunction influences augmented aortic hemodynamic responses to metaboreflex activation in postmenopausal women.

Postmenopausal women experience augmented aortic hemodynamic responses to isometric handgrip (IHG) exercise and metaboreflex activation post-exercise muscle ischemia (PEMI). Relationships between endothelial function brachial artery flow-mediated dilation (FMD) and aortic stiffness carotid-femoral pulse wave velocity (cfPWV) with aortic pulsatile hemodynamics during IHG and PEMI have not been determined. The relationships between aortic hemodynamic responses to PEMI were evaluated. Aortic blood pressure (BP), wave reflection, and pressure of forward (Pf) and backward (Pb) waves were measured using arterial tonometry at rest, IHG at 30% maximal force, and PEMI in 30 (15/group) postmenopausal women with low (≤ 4.5%) and normal (≥ 5.5%) FMD. Hemodynamic responses were analyzed as the change (Δ) from rest to the last minute of IHG and PEMI. Brachial and aortic systolic BP (SBP) responses to IHG were higher in the low vs normal FMD group (P < 0.05). Aortic SBP (Δ20 ± 8 vs Δ11 ± 7mmHg), pulse pressure (PP) (Δ12 ± 8 vs Δ6 ± 4mmHg), augmented pressure (AP) (Δ5 ± 3 vs Δ2 ± 2mmHg), and Pb (Δ6 ± 4 vs Δ3 ± 2mmHg) responses to PEMI were greater (P < 0.05) in women with low vs. normal FMD. FMD was negatively correlated with aortic SBP, PP, AP, and Pb (P < 0.05) responses to PEMI. cfPWV was not correlated with responses to PEMI. Endothelial dysfunction relates to augmented aortic pulsatile load during metaboreflex activation, which may increase cardiovascular risk in postmenopausal women.