Brachial Blood Pressure Measurements Research Articles

Generalised and visceral obesity metrics and ankle-brachial systolic blood pressures during pregnancy

Abstract Background Increased body mass index (BMI) (generalised obesity) and waist-to-height ratio (WHtR) (visceral obesity) are associated differently with brachial and ankle blood pressures in the general population. Ankle blood pressures are associated with blood glucose in pregnancy. This study investigates the relationship between BMI and WHtR with the brachial and ankle blood pressures separately during pregnancy. Methods Pregnant women were recruited during antenatal visits at an antenatal clinic in Bradford Royal Infirmary, UK, and their BMI, waist circumference, systolic, and diastolic blood pressure were clinically measured by staff in the second trimester. Additionally, blood pressure readings from both arms (left and right brachial arteries) and ankles [dorsalis pedis artery (DP) and posterior tibial artery (PT) on both sides] were obtained using Doppler by research staff. Results A total of 179 women participated, with an average BMI of 28.5 Kg/m2 (SD = 4.97) and average WHtR of 0.61 (SD = 0.08). BMI exhibited a positive correlation with all blood pressure measurements (r = 0.165 to 0.419, p < 0.05), while WHtR demonstrated significant correlations only with the right brachial, left PT, systolic and diastolic blood pressures (r: 0.170 to 0.271, p < 0.05). Moreover, BMI significantly associated with all blood pressure measurements in linear regression models, after adjusting for various sociodemographic and other factors, whereas WHtR significantly predicted only right brachial and left PT and some of the other blood pressure measurements. Conclusions BMI, and to a lesser extent WHtR, are associated with both brachial and ankle blood pressure measurements during pregnancy. These findings underscore the importance of recognizing the varying impacts of cardiometabolic risk factors for early detection and management of potential complications in pregnancy and the postpartum period. Key messages • BMI & WHtR are associated differently with brachial and ankle blood pressures in pregnancy. • Further exploration of combined non-invasive measurements like BMI, WHtR, brachial, and ankle blood pressures in early pregnancy for gestational diabetes mellitus and other co-morbidities is needed.

Concept, study design, and baseline nighttime blood pressure control status of the WISDOM-Night Study using a wrist-type oscillometric home blood pressure monitoring device.

There is growing evidence that nocturnal hypertension is an independent risk factor for cardiovascular diseases, including heart failure. However, brachial blood pressure (BP) measurements during sleep might themselves disturb sleep quality. We initiated a nationwide, multicenter observational prospective study using a wrist-type oscillometric nighttime BP monitoring device with new algorithms to measure supine BP accurately without sleep disturbance. This study, named the Wrist ICT-based Sleep and Circadian Blood Pressure Monitoring Program-Night BP Study (WISDOM-Night Study), was designed to clarify the impact of wrist-measured daily nighttime BPs on cardiovascular prognosis (stroke, coronary artery disease, heart failure, etc.) using 7 days of BP measurements at 2:00 a.m., 3:00 a.m., 4:00 a.m., and 4 h after bedtime. A total of 2751 patients with one or more cardiovascular risk factors were recruited between March 2021 and March 2024 and are currently being followed up for 7 years. Additionally, 1416 of the WISDOM-Night Study-enrolled patients who also agreed to participate in the WISDOM-Hypertension-Mediated Organ Damage (HMOD) Study underwent echocardiography to evaluate the association between wrist-measured BP and left ventricular structure. Data from this WISDOM-Night Study should provide the prospective association between nighttime BP and cardiovascular disease and reveal the indexes of nighttime BP with clinical pathological relevance. This first report of the WISDOM-Night Study describes the study design, baseline characteristics, and BP control status.

In silico data-based comparison of the accuracy and error source of various methods for noninvasively estimating central aortic blood pressure

Background and objectivesThe higher clinical significance of central aortic blood pressure (CABP) compared to peripheral blood pressures has been extensively demonstrated. Accordingly, many methods for noninvasively estimating CABP have been proposed. However, there still lacks a systematic comparison of existing methods, especially in terms of how they differ in the ability to tolerate individual differences or measurement errors. The present study was designed to address this gap. MethodsA large-scale ‘virtual subject’ dataset (n = 600) was created using a computational model of the cardiovascular system, and applied to examine several classical CABP estimation methods, including the direct method, generalized transfer function (GTF) method, n-point moving average (NPMA) method, second systolic pressure of periphery (SBP2) method, physical model-based wave analysis (MBWA) method, and suprasystolic cuff-based waveform reconstruction (SCWR) method. The errors of CABP estimation were analyzed and compared among methods with respect to the magnitude/distribution, correlations with physiological/hemodynamic factors, and sensitivities to noninvasive measurement errors. ResultsThe errors of CABP estimation exhibited evident inter-method differences in terms of the mean and standard deviation (SD). Relatively, the estimation errors of the methods adopting pre-trained algorithms (i.e., the GTF and SCWR methods) were overall smaller and less sensitive to variations in physiological/hemodynamic conditions and random errors in noninvasive measurement of brachial arterial blood pressure (used for calibrating peripheral pulse wave). The performances of all the methods worsened following the introduction of random errors to peripheral pulse wave (used for deriving CABP), as characterized by the enlarged SD and/or increased mean of the estimation errors. Notably, the GTF and SCWR methods did not exhibit a better capability of tolerating pulse wave errors in comparison with other methods. ConclusionsClassical noninvasive methods for estimating CABP were found to differ considerably in both the accuracy and error source, which provided theoretical evidence for understanding the specific advantages and disadvantages of each method. Knowledge about the method-specific error source and sensitivities of errors to different physiological/hemodynamic factors may contribute as theoretical references for interpreting clinical observations and exploring factors underlying large estimation errors, or provide guidance for optimizing existing methods or developing new methods.

O87 CONCORDANCE BETWEEN NOCTURNAL CARDIAC OUTPUT ESTIMATED WITH A NOVEL NON-INVASIVE METHOD USING BRACHIAL OSCILLOMETRIC BLOOD PRESSURE MEASUREMENTS AND ECHOCARDIOGRAPHY

Background and Objective: Nocturnal hypertension, characterized by elevated blood pressure (BP) levels during sleep as measured by 24-hour ambulatory blood pressure monitoring (24-h ABPM), has garnered increasing interest. However, understanding the explanatory mechanisms and non-invasive demonstration of these alterations poses challenges. We developed a non-invasive method to estimate cardiac output (CO) using brachial oscillometric BP measurements based on total arterial compliance (Ct). Yet, the agreement between estimated nocturnal CO and echocardiography-measured CO, considered the gold standard at rest, remains uncertain. This study aims to evaluate the concordance between the two methods. Methods: A cross-sectional study was conducted involving 216 adult patients who underwent Doppler echocardiograms and 24-h ABPM, regardless of valvular or cardiac pathology, or medication use, provided they had normal aortic valvular anatomy. Stroke volume was calculated as the product of the cross-sectional area of the aortic annulus and the average velocity of the left ventricular outflow tract. Using nocturnal BP and heart rate measurements from the 24-hour ABPM, along with weight, height, age, and sex, Ct and CO were estimated. Values were compared to determine validity. Results: Of the participants, 50.0% were men, with an average age of 54.0±14.0 years. Among them, three had a history of myocardial infarction, nineteen were diabetic, and one hundred thirty-six were hypertensive. CO measured by echocardiography averaged 4.9±1.0 L/min, ranging from 2.8 to 8.1 L/min. The agreement of CO between the new method and Doppler echocardiography was good, with an intraclass correlation coefficient of 0.421 (95%CI 0.305 to 0.525). The mean difference was 0.027±0.977 L/min (95%CI -0.104 to -0.157). Bland-Altman plots demonstrated that the differences between the methods were randomly distributed along the mean difference line (Figure). Conclusions: The novel method for estimating nocturnal CO based on Ct using brachial oscillometric BP measurements demonstrate validity across various clinical conditions. Its adoption in clinical settings could simplify the assessment of nocturnal hypertension with 24-h ABPM.

O83 ESTIMATING CARDIAC OUTPUT FROM ARTERIAL BLOOD PRESSURE WITHOUT PRESSURE WAVEFORMS

Background and Objective: Noninvasive estimations of cardiac Output (CO) using pulse wave analysis have been studied for over a century, yielding contrasting results. Our research group has developed a novel method for the noninvasive estimation of CO based on brachial blood pressure (BP) measurements and total arterial compliance (Ct), eliminating the need for arterial pulse wave analysis. This study compares all reported methods for estimating CO without pulse wave contours using the same dataset to assess their accuracy. Methods: A cross-sectional study was conducted involving 447 adult patients who underwent ambulatory transthoracic Doppler echocardiograms. Stroke volume (SV) was calculated as the product of the cross-sectional area of the aortic annulus and the average velocity of the left ventricular outflow tract. Simultaneously, oscillometric BP measurements were obtained, and CO was derived from Ct utilizing anthropometric variables, BP, and heart rates (HR). Calibration was conducted with 75% of the data using the formula: CO=K0+K1×estimator. The remaining 25% of the data was used for validation, with Bland-Altman analysis and the intraclass correlation coefficient (ICC). Calibration involved the following CO estimators: i) mean arterial pressure; ii) HR; iii) pulse pressure (PP); iv) PPxHR; v) Warner time-correction; vi) Liljestrand-Zander; vii) Wesseling-Langewouters; and viii) the new Ct-based method. Results: Of the participants, 51.2% were men, with an average age of 51.0±15.0 years, weight of 75.0±14.0 kg, and height of 166.0±9.5 cm. The CO by echocardiography had an average of 4.9±1.0 L/min, with a range of 2.0 to 8.5 L/min. Among the compared methods, the new Ct-based method showed the smallest mean difference and error, as well as the largest ICC. The Bland-Altman analysis shows a normal distribution for the new Ct-based method, with agreement limits between -1.56 to 1.48 L/min (Figure). Conclusions: The new Ct-based method developed surpasses other published methods and exhibits practical accuracy suitable for ambulatory use, such as hemodynamic monitoring of pathophysiological or therapeutic outcomes.

P072 VALIDATION OF A NOVEL METHOD FOR NONINVASIVE ESTIMATION OF CARDIAC OUTPUT USING BRACHIAL OSCILLOMETRIC BLOOD PRESSURE MEASUREMENTS IN PATIENTS WITH VARIOUS CLINICAL CONDITIONS

Background and Objective: Estimating cardiac output (CO) and other hemodynamic parameters from blood pressure (BP) measurements could aid in selecting appropriate antihypertensive treatments in clinical settings. Our research group has developed a non-invasive method to estimate CO based on total arterial compliance (Ct). However, its validity in populations with various cardio-metabolic chronic diseases remains uncertain. The objective of this study is to assess the validity of our CO estimation method across different patient with varied clinical conditions. Methods: A cross-sectional study was conducted involving 217 adult patients who underwent ambulatory transthoracic Doppler echocardiograms, irrespective of valvular or cardiac pathology, or medication use, provided they had normal aortic valvular anatomy. Stroke volume was calculated as the product of the cross-sectional area of the aortic annulus and the average velocity of the left ventricular outflow tract. Simultaneously, oscillometric BP measurements were obtained. Subsequently, the CO values obtained via Doppler echocardiography and those estimated based on Ct were compared to determine validity. Ct was estimated as: Ct/BSA= 38/PPth + 4/5 × Td/T - 3/7, where BSA denotes body surface area, Td signifies diastolic time, T represents the cardiac period, and PPth refers to the theoretical pulse pressure. Results: Of the participants, 49.7% were men, with an average age of 54.0±14.0 years. Among them, three had a history of acute myocardial infarction, one had a pacemaker, nineteen were diabetic, and one hundred thirty-six were hypertensive. CO by echocardiography averaged 4.9±1.0 L/min, ranging from 2.0 to 8.5 L/min. The agreement of CO between the new method and Doppler echocardiography was good. Bland-Altman plots showed that the differences between the methods were randomly distributed along the mean difference line (Figure). Conclusions: The novel method for noninvasive estimation of CO based on Ct with brachial oscillometric BP measurements in patients with various clinical conditions is deemed valid. Its implementation in clinical practice has the potential to transform patient assessment.

Actigraphy-based sleep and muscle sympathetic nerve activity in humans.

Short and insufficient sleep are prevalent and associated with cardiovascular disease, with the sympathetic nervous system as a suspected mediator. The purpose of the present study was to investigate the association between objective, actigraphy-based total sleep time (TST), sleep efficiency (SE), and cardiovascular and sympathetic regulation in healthy adults. We hypothesized that short TST and low SE would be associated with elevated resting blood pressure, heart rate (HR), and muscle sympathetic nerve activity (MSNA). Participants included 94 individuals [46 males, 48 females, age: 30 ± 15 yr, body mass index (BMI): 26 ± 4 kg/m2]. All participants underwent at least 7 days of at-home, wristwatch actigraphy monitoring (avg: 10 ± 3 days). Seated blood pressures were assessed using brachial blood pressure measurements, followed by a 10-minute supine autonomic testing session consisting of continuous HR (electrocardiogram), beat-by-beat blood pressure (finger plethysmograph), and MSNA (microneurography) monitoring. Partial correlations were used to determine the relationship between sleep and cardiovascular parameters while accounting for the influence of age, sex, and BMI. TST was not associated with MAP (R = -0.105, P = 0.321), HR (R = 0.093, P = 0.383), or MSNA burst frequency (BF; R = -0.168, P = 0.112) and burst incidence (BI; R = -0.162, P = 0.124). Similarly, SE was not associated with MAP (R = -0.088, P = 0.408), HR (R = -0.118, P = 0.263), MSNA BF (R = 0.038, P = 0.723), or MSNA BI (R = 0.079, P = 0.459). In contrast to recent preliminary findings, our results do not support a significant association between actigraphy-based sleep duration or efficiency and measures of resting blood pressure, heart rate, and MSNA.NEW & NOTEWORTHY The present study investigated the independent association between actigraphy-based sleep duration, efficiency, and measures of blood pressure, heart rate, and muscle sympathetic nerve activity (MSNA) in adult males and females. Contrary to our hypothesis, the findings do not support an independent association between habitual sleep and cardiovascular or sympathetic neural activity. However, these findings do not preclude a potential association between these parameters in populations with sleep disorders and/or cardiovascular disease.

EVALUATION OF A PROTOTYPE CUFFLESS MULTI-SENSOR DEVICE TO TRACK BLOOD PRESSURE CHANGES

Objective: Accurate measurements are essential if cuffless blood pressure (BP) devices are to be used in hypertension care. The aim of the present study was to evaluate the ability of a prototype cuffless device (XXXXX) to track changes in BP compared to a non-invasive, continuous BP monitor (reference BP; Human NIBP Nano system, ADInstruments, Dunedin, New Zealand) in an experimental laboratory set up. Design and method: After ethical approval, three external techniques (Figure 1) to induce BP changes via different physiological mechanisms, were applied in 23 healthy subjects. Continuous data from the prototype cuffless device on the upper arm was obtained simultaneously with reference BP measurements. The cuffless device measures skin temperature, 3D acceleration, 3D angular velocity and photoplethysmography. Data from 16 of the participants were used to train a machine learning model, which was then used to estimate BP (15-second resolution) on data from 7 other participants. The cuffless BP device was calibrated once using brachial cuff BP measurement (WatchBP O3, Microlife, Cambridge, United Kingdom). The present study provides preliminary results from a larger on-going study designed to evaluate performance of the cuffless device according to ISO 81060-3:2022 standard. Results: A timeseries plot displaying BP measurements from the cuffless and the reference device is displayed in Figure 2. The mean error (± corrected standard deviation of error) was 2.4 (± 7.9) mmHg for systolic blood pressure (SBP) and 1.7 (± 7.4) mmHg for diastolic blood pressure (DBP) for the accuracy requirement. The corresponding errors for stability requirements were 1.9 (± 8.1) and 1.9 (± 6.0) mmHg for SBP and DBP. Conclusions: The present study demonstrated that the prototype cuffless BP device could track BP changes with high accuracy in healthy subjects in a laboratory setting. The cuffless device fulfilled the acceptance criteria (± 6 (± 10) mmHg) for the accuracy and stability requirements from the ISO 81060-3:2022 standard. Further research is necessary to determine accuracy of the prototype cuffless BP device during real-life conditions as described in the 2023 ESH recommendations for the validation of cuffless devices.

COMPARISON OF CALIBRATION METHODS IN THE PRECISION OF A RING-TYPE CUFFLESS BLOOD PRESSURE MEASUREMENT DEVICE

Objective: This study aimed to compare the efficacy of two calibration methods for a ring-type cuffless blood pressure (BP) measurement device, CART-I Plus, to assess if regular calibration with a traditional brachial arm cuff device enhances its precision. Design and method: The study involved 40 patients, with 28 completing the study. Participants underwent calibration in three different positions (sitting, standing, supine). Prior to the initial calibration, they were seated quietly for 3–5 minutes. Calibration was executed using a conventional brachial arm cuff device on the same arm. In each position, calibration was performed twice, separated by a minimum interval of one minute. A rest period exceeding two minutes was allowed between position changes for stabilization. BP estimates from the CART-I Plus, derived from photoplethysmography signals, were then compared with corresponding conventional 24-hour ambulatory BP monitoring (ABPM) measurements. Results: The mean differences between the CART-I Plus and ABPM, when calibrated using the sitting position alone (twice), were -2.12±8.53/2.36±7.82 mmHg (awake/sleep SBP) and -4.11±7.73/0.27±7.99 mmHg (awake/sleep DBP), respectively. When calibration included all three positions (six total calibrations), the mean differences remained similar; -2.14±8.95/2.17±8.53 mmHg (awake/sleep SBP) and -4.10±7.91/0.25±7.73 mmHg (awake/sleep DBP) (p > 0.5). Neither the standing nor the supine position, nor a combination of sitting and supine positions, significantly improved precision. In both standing and supine positions, the devices demonstrated a strong correlation for systolic blood pressure (SBP) (r=0.86 and r=0.90, respectively) and diastolic blood pressure (DBP) (r=0.90 for both), with all correlations being statistically significant (p < 0.001). Conclusions: Provided that patient stabilization is adequately ensured, and precise brachial BP measurements are taken by medical personnel, a single sitting position calibration appears to be sufficient. The addition of dynamic three-point calibration involving standing and supine positions did not significantly enhance precision.

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<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.

Vascular Health of Females with History of Assisted Reproductive Technology.

The use of assisted reproductive technologies (ART) for the treatment of infertility is gaining popularity. Limited data on the overall vascular health of females with history of ART are available. This pilot study aimed to investigate the overall vascular health of females with history of ART compared to individuals who conceived spontaneously. The assessment of overall vascular health included the measurement of brachial blood pressure, central blood pressure, and pulse wave velocity, as well as the evaluation of the arterial stiffness and carotid intima-media thickness (cIMT) of the common carotid arteries. Conventional blood lipids including lipoprotein a (Lp(a)) were also determined. In total, 45 females with history of ART and 52 females who conceived spontaneously were included (mean age: 47.72 ± 5.96 years vs. 46.84 ± 7.43 years, p = 0.525). An initial comparison revealed a significantly higher prevalence of elevated Lp(a) in ART females (p = 0.011). However, after multiple comparison correction, the significant result disappeared (p = 0.132). Within the cohort of ART females, no significantly higher cardiovascular risk was detected regarding vascular function. The potentially higher prevalence of elevated Lp(a) in ART females must be further investigated in future studies, as it might contribute to the impaired reproductive process in this cohort.

Synchronous Bilateral Brachial Blood Pressure Measurements Increased Orthostatic Hypotension Detection in the Elderly.

Orthostatic hypotension (OH) is a common clinical sign, but its detection rate is low, and it is difficult to repeat because there is no standardized screening method available. This study aimed to establish a method for detecting blood pressure and assess whether it could increase the OH detection rate in the elderly. From May to October, 2022, 178 patients with symptomatic OH and 286 subjects with asymptomatic OH were selected. BP from the bilateral brachial artery was measured using two electronic sphygmomanometers on both arms at the same time, in the order of supine, sitting, and standing at 0-3 min. OH should meet 20/10 mmHg, standing BP minus sitting BP. The OH detection rates were calculated and compared. The symptomatic OH group was more often older, slimmer, had lower ADL scores, and contained fewer smokers (all P< 0.05). The detection rate of the symptomatic OH group using the modified method was 59.55%, which was higher than that of the routine method (34.83% vs. 59.55%, P<0.05). The detection rate using the modified method in the OH group with asymptomatic OH was 20.63%, which was higher than that of the routine method (20.63% vs. 5.59%, P< 0.01). Synchronous measurement of bilateral brachial artery BP in supine, sitting, and standing positions increased the detection rate of OH in the elderly.

Contractility, ventriculoarterial coupling, and stroke work after acute myocardial infarction using CMR-derived pressure-volume loop data.

Noninvasive left ventricular (LV) pressure-volume (PV) loops derived by cardiac magnetic resonance (CMR) have recently been shown to enable characterization of cardiac hemodynamics. Thus, such PV loops could potentially provide additional diagnostic information such as contractility, arterial elastance (Ea ) and stroke work (SW) currently not available in clinical routine. This study sought to investigate to what extent PV-loop variables derived with a novel noninvasive method can provide incremental physiological information over cardiac dimensions and blood pressure in patients with acute myocardial infarction (MI). A total of 100 patients with acute MI and 75 controls were included in the study. All patients underwent CMR 2-6 days after MI including assessment of myocardium at risk (MaR) and infarct size (IS). Noninvasive PV loops were generated from CMR derived LV volumes and brachial blood pressure measurements. The following variables were quantified: Maximal elastance (Emax ) reflecting contractility, Ea , ventriculoarterial coupling (Ea /Emax ), SW, potential energy, external power, energy per ejected volume, and efficiency. All PV-loop variables were significantly different in MI patients compared to healthy volunteers, including contractility (Emax : 1.34 ± 0.48 versus 1.50 ± 0.41 mmHg/mL, p = .024), ventriculoarterial coupling (Ea /Emax : 1.27 ± 0.61 versus 0.73 ± 0.17, p < .001) and SW (0.96 ± 0.32 versus 1.38 ± 0.32 J, p < .001). These variables correlated to both MaR and IS (Emax : r2 = 0.25 and r2 = 0.29; Ea /Emax : r2 = 0.36 and r2 = 0.41; SW: r2 = 0.21 and r2 = 0.25). Noninvasive PV-loops provide physiological information beyond conventional diagnostic variables, such as ejection fraction, early after MI, including measures of contractility, ventriculoarterial coupling, and SW.

Smartphone-Based versus Non-Invasive Automatic Oscillometric Brachial Cuff Blood Pressure Measurements: A Prospective Method Comparison Volunteer Study.

Introduction: Mobile health diagnostics have demonstrated effectiveness in detecting and managing chronic diseases. This method comparison study aims to assess the accuracy and precision of the previously evaluated OptiBP™ technology over a four-week study period. This device uses optical signals recorded by placing a patient's fingertip on a smartphone's camera to estimate blood pressure (BP). Methods: In adult participants without cardiac arrhythmias and minimal interarm blood pressure difference (systolic arterial pressure (SAP) < 15 mmHg or diastolic arterial pressure (DAP) < 10 mmHg), three pairs of 30 s BP measurements with the OptiBP™ (test method) were simultaneously compared using three pairs of measurements with the non-invasive oscillometric brachial cuff (reference method) on the opposite arm over a period of four consecutive weeks at a rate of two measurements per week (one in the morning and one in the afternoon). The agreement of BP values between the two technologies was analyzed using Bland-Altman and error grid analyses. The performance of the smartphone application was investigated using the International Organization for Standardization (ISO) definitions, which require the bias ± standard deviation (SD) between two technologies to be lower than 5 ± 8 mmHg. Results: Among the 65 eligible volunteers, 53 participants had adequate OptiBP™ BP values. In 12 patients, no OptiBP™ BP could be measured due to inadequate signals. Only nine participants had known chronic arterial hypertension and 76% of those patients were treated. The mean bias ± SD between both technologies was -1.4 mmHg ± 10.1 mmHg for systolic arterial pressure (SAP), 0.2 mmHg ± 6.5 mmHg for diastolic arterial pressure (DAP) and -0.5 mmHg ± 6.9 mmHg for mean arterial pressure (MAP). Error grid analyses indicated that 100% of the pairs of BP measurements were located in zones A (no risk) and B (low risk). Conclusions: In a cohort of volunteers, we observed an acceptable agreement between BP values obtained with the OptiBPTM and those obtained with the reference method over a four-week period. The OptiBPTM fulfills the ISO standards for MAP and DAP (but not SAP). The error grid analyses showed that 100% measurements were located in risk zones A and B. Despite the need for some technological improvements, this application may become an important tool to measure BP in the future.

Association of Central Blood Pressure and Carotid Intima Media Thickness with New-Onset Hypertension in People with High Normal Blood Pressure.

People with high normal blood pressure (BP) have a higher risk of cardiovascular events than those with normal BP; therefore, progression to hypertension (HT) should be prevented. We aimed to assess the HT risk using central BP and carotid intima media thickness (CIMT) in people with high normal BP. This prospective cohort study used the Tohoku Medical Megabank Community-Based Project Cohort Study (conducted from 2013 in Miyagi Prefecture in Japan). The participants had a high normal BP, defined as a systolic BP of 120-139 mmHg and diastolic BP ＜90 mmHg using brachial BP measurement during the baseline survey. The outcome was new-onset HT during the secondary survey, conducted four years after the baseline survey. Overall, 4,021 participants with high normal BP during the baseline survey, with an average age of 58.7 years, were included; 1,030 (26%) were diagnosed with new-onset HT during the secondary survey, 3.5±0.7 years after the baseline survey. The multivariable odds ratio (95% confidence interval) for HT in the highest versus lowest quartile of central BP was 1.7 (1.2-2.4, p=0.0030), and that of CIMT was 1.8 (1.4-2.4, p＜0.001). Subgroup analysis according to age (＜60 and ≥ 60 years) and sex revealed that the central BP was influential in groups with younger age and female individuals; CIMT was influential in all groups. Higher central BP and thicker CIMT at the baseline were correlated with new-onset HT in individuals with high normal BP, independent of brachial systolic BP and other cardiovascular risk factors.

Non-invasive estimation of left ventricular systolic peak-pressure: a prerequisite to calculate of myocardial work in hypertrophic obstructive cardiomyopathy

Abstract Introduction Myocardial work (MW) is an echocardiographic parameter to estimate global and regional myocardial performance. This method utilizes pressure strain loops derived from global longitudinal strain (GLS) and left ventricular systolic pressure (LVSP) estimated by brachial blood pressure (BP). Purpose Since LVSP cannot be equated with BP in pts with HOCM, we investigated whether the LVSP can be calculated non-invasively by combining Doppler echo parameters and the BP. This estimation is mandatory to make MW applicable for HOCM-pts. Methods We studied 20 consecutive pts (8 women, 12 men; mean age 57.0±13.9 years; NYHA class 2.1±0.8) with indication for first alcohol septal ablation. 6 pts had hypertension and 2 pts unexplained syncope. 18 (90%) pts were in sinus rhythm. NTproBNP was 1431 pg/ml (1912 IQR). Echo baseline measurements showed subaortic septal (IVS) thickness of 21.0±5.0 mm and maximal IVS thickness of 24.7±6.3 mm. Pts showed high-normal left ventricular ejection fraction (70.4±10.1%). Left atrial (LA) volume was 101.2±26 ml. All measurements of pressures and gradients were performed in the catheterization laboratory after placement of a 5F Judkins JR4 in the ascending aorta and a 5.2F special pigtail catheter in the apex of LV beyond the obstruction. Simultaneous measurements of BP at left upper arm, echo intraventricular gradients (instantaneous and mean) with CW Doppler (GE Vivid E70), and invasive pressures and gradients (peak-to-peak and mean) of the LV and ascending aorta were performed. Echo and invasive gradients were averaged over 3 cardiac cycles. Finally, we tried to identify an estimation of invasively measured LV systolic pressure by combining systolic BP and echo measured gradients. Results Systolic BP was 143±21 mmHg. Max. CW Doppler gradient was 65±29 mmHg and mean gradient was 31±14 mmHg. Invasive simultaneous measurements at rest showed peak-to-peak gradient of 55±24 mmHg and mean gradient of 34±13 mmHg between apical LV and ascending aorta. Mean LVSP was 190±40 mmHg. Systolic pressure of the ascending aorta was 134±28 mmHg. Adding systolic peripheral BP and maximal echo-gradient mean value was 208±38 mmHg. Adding systolic peripheral BP and echo-mean gradient mean value was 174±26 mmHg. Correlating these values with the invasively measured systolic LV pressure we found a slightly higher correlation of the sum of systolic BP and mean-echo gradient (Pearson correlation coefficient: 0.867 p&amp;lt;0.001) compared with the sum of systolic BP and maximal echo-gradient (Pearson correlation coefficient: 0.851; p&amp;lt;0.001). Bland–Altman plots demonstrated good levels of agreements between invasively measured LVSP and both non-invasively estimated LVSP. Conclusions Non-invasive estimation of LVSP is feasible by combining conventional BP and CW Doppler measured mean LV outflow tract gradient in HOCM. Hereby estimation of MW in pts with HOCM is applicable.

Invasively Measured Aortic Systolic Blood Pressure and Office Systolic Blood Pressure in Cardiovascular Risk Assessment in CKD

IntroductionCentral aortic blood pressure (BP) could be a better risk predictor than brachial BP. This study examined whether invasively measured aortic systolic BP improved outcome prediction beyond risk prediction by conventional cuff-based office systolic BP in patients with and without chronic kidney disease (CKD). MethodsIn a prospective, longitudinal cohort study aortic and office systolic BPs were registered in patients undergoing elective coronary angiography. CKD was defined as estimated glomerular filtration rate <60 ml/min/1.73 m2. Multivariable Cox models were used for the association with incident myocardial infarction (MI), stroke, and death. ResultsAortic and office systolic BPs were available in 39,866 patients (mean age: 64 years; 58% males; 64% with hypertension) out of which 6,605 (17%) had CKD. During a median follow-up of 7.2 years (interquartile range: 4.6-10.1 years), 1,367 strokes (CKD: 353), 1,858 MIs (CKD: 446) and 7,551 deaths (CKD: 2,515) occurred. CKD increased the risk of stroke, MI and death significantly. Office and aortic systolic BP were both associated with stroke in non-CKD patients (adjusted hazard ratios with 95% confidence interval per 10 mmHg: 1.08 (1.05–1.12) and 1.06 (1.03–1.09), respectively) and with MI in CKD patients (adjusted hazard ratios: 1.08 (1.03–1.13) and 1.08 (1.04–1.12), respectively). There was no significant difference between prediction of outcome with office or aortic systolic BP when adjusted models were compared with C-statistics. ConclusionRegardless of CKD status, invasively measured central aortic systolic BP does not improve the ability to predict outcome compared with brachial office BP measurement.

Association of subendocardial viability ratio and mortality in the elderly population: results from the CARdiovascular disease, Living and Ageing in Halle study.

The subendocardial viability ratio (SEVR) reflects the balance of myocardial oxygen supply and demand. Low SEVR indicates a reduced subendocardial perfusion and has been shown to predict mortality in patients with kidney disease and diabetes. The aim of this study is to investigate the association of SEVR and mortality in the elderly population. We analysed data from the CARdiovascular disease, Living and Ageing in Halle (CARLA) study. SEVR was estimated noninvasively by radial artery tonometry and brachial blood pressure measurement. The study population was divided into a low (SEVR ≤130%) and normal (SEVR >130%) SEVR group. Cox-regression was used for survival analysis. In total, 1414 participants (635 women, 779 men) aged from 50 to 87 years (mean age 67.3 years) were included in the analysis. The all-cause mortality was 22.7% during a median follow-up of 10.5 years. The unadjusted association of SEVR with all-cause mortality decreased from 3.52 (1.31-9.46) [hazard ratio (95% confidence interval) for low SEVR ≤ 130% versus normal SEVR > 130%] among those younger than 60 years to 0.86 (0.50-1.48) among those older than 80 years and from 1.81 (0.22-14.70) to 0.75 (0.30-1.91) for cardiovascular mortality. Sex-specific unadjusted analyses demonstrated an association of SEVR with all-cause and cardiovascular mortality in men [2.32 (1.61-3.34) and 2.24 (1.18-4.24)], but not in women [1.53 (0.87-2.72) and 1.14 (0.34-3.82)]. Our data suggests that SEVR is an age dependent predictor for all-cause mortality, predominantly in men younger than 60 years.

Blood Pressure Measurement Based on the Camera and Inertial Measurement Unit of a Smartphone: Instrument Validation Study.

Even though several mobile apps that can measure blood pressure have been developed, the data about the accuracy of these apps are limited. We assessed the accuracy of AlwaysBP (test) in blood pressure measurement compared with the standard, cuff-based, manual method of brachial blood pressure measurement (reference). AlwaysBP is a smartphone software that estimates systolic blood pressure (SBP) and diastolic blood pressure (DBP) based on pulse transit time (PTT). PTT was calculated with a finger photoplethysmogram and seismocardiogram using, respectively, the camera and inertial measurement unit sensor of a commercially available smartphone. After calculating PTT, SBP and DBP were estimated via the Bramwell-Hill and Moens-Korteweg equations. A calibration process was carried out 3 times for each participant to determine the input parameters of the equations. This study was conducted from March to August 2021 at Chungnam National University Sejong Hospital with 87 participants aged between 19 and 70 years who met specific conditions. The primary analysis aimed to evaluate the accuracy of the test method compared with the reference method for the entire study population. The secondary analysis was performed to confirm the stability of the test method for up to 4 weeks in 15 participants. At enrollment, gender, arm circumference, and blood pressure distribution were considered according to current guidelines. Among the 87 study participants, 45 (52%) individuals were male, and the average age was 35.6 (SD 10.4) years. Hypertension was diagnosed in 14 (16%) participants before this study. The mean test and reference SBPs were 120.0 (SD 18.8) and 118.7 (SD 20.2) mm Hg, respectively (difference: mean 1.2, SD 7.1 mm Hg). The absolute differences between the test and reference SBPs were <5, <10, and <15 mm Hg in 57.5% (150/261), 84.3% (220/261 ), and 94.6% (247/261) of measurements. The mean test and reference DBPs were 80.1 (SD 12.6) and 81.1 (SD 14.4) mm Hg, respectively (difference: mean -1.0, SD 6.0 mm Hg). The absolute differences between the test and reference DBPs were <5, <10, and <15 mm Hg in 75.5% (197/261), 93.9% (245/261), and 97.3% (254/261) of measurements, respectively. The secondary analysis showed that after 4 weeks, the differences between SBP and DBP were 0.1 (SD 8.8) and -2.4 (SD 7.6) mm Hg, respectively. AlwaysBP exhibited acceptable accuracy in SBP and DBP measurement compared with the standard measurement method, according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization protocol criteria. However, further validation studies with a specific validation protocol designed for cuffless blood pressure measuring devices are required to assess clinical accuracy. This technology can be easily applied in everyday life and may improve the general population's awareness of hypertension, thus helping to control it.