24-hour Ambulatory Blood Pressure Monitoring Research Articles

Evaluation of renal functional reserve in patients with preserved renal function and coronary microvascular disease

Abstract Background/introduction Renal Functional Reserve (RFR) stands as a subject of significant scientific discussion,holding promise as a diagnostic tool for early detection of subclinical renal disorders. Literature establishes a link between chronic kidney disease & cardiovascular disease (CVD). Purpose This study aims to assess RFR in patients with coronary microvascular dysfunction (CMD), while maintaining preserved renal function (eGFR≥60ml/min/1.73m2 by CKD-EPI criteria)&proteinuria<400mg/24hr. The investigation seeks to provide insights into the nuanced relationship between renal function&CMD, offering potential early indicators of CVD. Methods This is a single-center, prospective study enrolling patients with CMD. In the absence of significant coronary artery disease, functional coronary circulation assessment was performed. Coronary flow reserve (CFR) & index of microvascular resistance (IMR) were measured invasively with bolus thermodilution technique. In all participants, RFR was estimated by endogenous creatinine clearance after oral protein load (cooked meal, 1.2gr/kg). Normal RFR was defined as≥30 ml/min/1.73m2. Also, patients with CMD were offered 24-hour Ambulatory Blood Pressure Monitoring (ABPM). Results A total of 25 participants have been enrolled so far in study: 11 without CMD - control group [7 female, 64%, mean age: 52.9±8.8 years) & 14 with CMD – CMD group (11 female, 79%, mean age: 53.5±10,3 years). CMD patients were classified into 2 groups, structural & functional endotype (CFR<2.5 & IMR≥25 were considered abnormal). The RFR value for CMD & control group is 7.4±6.3 vs 36.3±5.8 ml/min/1.73m2 respectively (p<0.05). This difference between groups remained statistically significant after controlling for confounding factors. It was found that RFR value for functional & structural CMD endotype was 3.8±2.6 & 9.6±7,2 ml/min/1.73m2 respectively (p=0.06). Furthermore, no statistical significance was found between RFR and IMR, CFR indices. According to data from ABPM, there were no significant differences in ambulatory blood pressure (both systolic and diastolic) between the two endotypes of CMD, as well as no relationship with RFR was observed. However, the proportion of non-dipping BP pattern was significantly higher in functional CMD endotype (p<0.05). It was not found correlation between RFR & non-dipping phenotype. Conclusions Impaired RFR is evident across all individuals experiencing microvascular angina. Furthermore, those with functional CMD exhibit a diminished RFR when compared with their counterparts with structural CMD. RFR does not exhibit a correlation with blood pressure levels or the absence of a nocturnal dipping pattern. In light of the hypothesis asserting that appraising renal functional reserve serves as an early diagnostic measure for subclinical renal disorders, promptly recognizing individuals with distinct phenotypes could facilitate tailoring therapeutic interventions on an individual basis.Functional Coronary AngiogramCMD group baseline characteristics

To compare 24 hour blood pressure values of a conventional 24 hours ambulatory blood pressure device versus a wristband using an artificial intelligence algorithm based on photophletysmography

Abstract Background Ambulatory Blood Pressure Monitoring is of high added value in determining blood pressure, but also highly relevant quantitatively, as hypertension is the single most common medical condition. Unfortunately, practical and qualitative limitations are numerous. Purpose To determine the accuracy of a novel wrist-worn cuff-calibrated photoplethysmography (PPG)-based remote patient monitoring device versus ambulatory blood pressure monitoring (ABPM). Methods The single-center prospective study included 40 adult patients with standard 24-hour ABPM with a 30-minute measurements. Participants used a wrist-worn PPG device during the ABPM period. Measurements of the average difference and standard deviation (SD) for the full 24-hour period as well as for awake and asleep periods were compared. Differences in awake-asleep BP change between the investigational and reference device were described for all, and per nighttime BP dipper category. And also, investigational BP monitoring accuracy under motion will be visualised. Results During the 24-hour period the absolute difference in average SBP and DBP was 3.65 (SD±4.57) and 2.98 (SD±3.91), respectively. Similar results were found for the subsets of day- and nighttime determinations. The absolute difference in average awake-asleep BP change was 2.36 (SD ± 2.40) for SBP and 2.17 (SD ± 2.13) for DBP. Comparable absolute differences were present within each of the nighttime dipper categories. The performance of the investigational device remained stable during motion. Conclusions This study demonstrates initial evidence supporting the accuracy of the evaluated wrist-worn PPG-based device in measuring 24-hour as well as day- and nighttime BP. In the average difference and SD remained within ISO-81060-2:2018 cut-off values from recent ESH guidelines. Therefore, the presented method can provide an accurate and more patient friendly alternative to ABPM.

Masked hypotension in patients with heart failure

Abstract Background Hypotension limits the up-titration of guideline-directed medical therapies (GDMTs) and correlates with poor prognosis in patients with heart failure. The value of ambulatory blood pressure monitoring (ABPM) in heart failure patients and its association with GDMTs optimization and clinical outcomes were undetermined. Methods REM-HF (Risk Evaluation and Management in Heart Failure) is a multicenter, prospective observational cohort. Our study screened patients from REM-HF who were hospitalized for incident HF and newly initiated GDMTs between April 2018 and December 2022. Eligible participants conducted a 24-hour ABPM before discharge and were followed-up as the cohort routine. GDMTs target dose achievement and dose trajectories were assessed at 3-month visit. The primary outcome was a composite of all-cause mortality and heart failure readmission. Results On adjusted restricted cubic spline analysis, office SBP demonstrated a U-shape relationship with the primary outcome (P for nonlinearity=0.003), while 24-hour SBP was linear (P for nonlinearity=0.338). The risk-related threshold of ambulatory and office systolic hypotension was defined as corresponding SBP < 120 mmHg accordingly. Combining these two measurements together, we described three blood pressure status as sustained hypotension (s-hypo, both SBP < 120 mmHg), masked hypotension (m-hypo, 24h SBP < 120 mmHg while office SBP ≥ 120mmHg), and non-hypotension (n-hypo). Among the 491 patients included, 124 (25.3%), 151 (30.8%) and 216 (44.0%) had s-hypo, m-hypo, and n-hypo, respectively. The m-hypo group showed similar clinical features as the s-hypo subjects, including more serious left ventricle remodeling and worse cardiac function. After the GDMTs dose titration, either patients with s-hypo or m-hypo were as unlikely to achieve target dose as the non-hypotensives (OR for s-hypo 0.42, 95%CI 0.19-0.95, P=0.038; OR for m-hypo 0.39, 95%CI 0.19-0.80, P=0.011). During a median follow-up of 693 days, the adjusted risk of primary outcome was higher in the s-hypo group and m-hypo group compared with the non-hypo group (HR for s-hypo 2.47, 95%CI 1.54-3.96, P<0.001; HR for m-hypo 1.68, 95%CI 1.06-2.65, P=0.027). No significant differences were found in target dose achievement and clinical outcomes between the s-hypo and m-hypo groups. Conclusion Masked systolic hypotension can occur in nearly one-third of new-onset HF patients. Patients with m-hypo and s-hypo exhibit similar clinical characteristics, both associated with GDMTs intolerance and adverse outcomes, suggesting m-hypo deserves recognition as a discrete entity. ABPM provides a more comprehensive view of patients’ blood pressure status by identifying this population.

Ambulatory blood pressure monitoring in Egyptian children with nephrotic syndrome: single center experience

BackgroundHypertension (HTN), especially masked hypertension, is one of the cardiovascular consequences of nephrotic syndrome. Masked hypertension cannot be identified during routine follow-up visits and adversely effects the patients’ cardiac function. The purpose of this study was to use ambulatory blood pressure monitoring (ABPM) to evaluate the blood pressure status of children with nephrotic syndrome.MethodsNinety children with nephrotic syndrome (NS) participated in this cross-sectional study, which was carried out at Cairo University Children Hospital’s nephrology clinic (CUCH). A sphygmomanometer was used in the clinic to measure blood pressure, and a Meditech monitor was used for 24-hour ambulatory blood pressure monitoring (ABPM). Interventricular septum (IVS) was measured, and heart functions were evaluated, using echocardiography.ResultsTwo groups comprised the included patients: Group1 (n = 70): HTN group included masked and ambulatory hypertension, and Group 2 (n = 20): non-HTN group included normal blood pressure, white coat HTN and well controlled HTN, 35% of the studied cohort (n = 32/90) had masked HTN.The serum urea was significantly higher in HTN group than non-HTN group with p-value: 0.047, while the serum albumin was significantly lower in HTN group than non-HTN group with p-value: 0.017. The cut-off point of 9.9, the sensitivity and specificity of serum urea to predict the occurrence of hypertension in NS patients was 92.9% and 35% respectively, with p-value : 0.024 and 95% CI (0.534–0.798). The z score of IVS is significantly higher in group 1 (2.5 ± 1.2) when compared to group 2 (1.7 ± 2.1) with p-value: 0.025 and Among group 1, it was noticed that 74% (n = 52/70) of them were systolic non-dipper, also it was observed that the mean serum potassium and cholesterol were significantly higher among systolic non-dipper when compared with systolic dipper patients with p-values: 0.045 and 0.005 respectively.ConclusionChildren with nephrotic syndrome are particularly vulnerable to experience ambulatory hypertension and masked hypertension, which may adversely impact their cardiac condition because they are not detectable by standard blood pressure readings at the clinic.

Clinical Impact of 3- versus 5-Minute Delay and 30- versus 60-Second Intervals on Unattended Automated Office Blood Pressure Measurements.

Guidelines advise automated office blood pressure (AOBP) with an initial 5-minute delay and multiple measurements at least 60 seconds apart. Recent studies suggest that AOBP may be accurate with shorter delays or intervals, but evidence in clinical settings is limited. Patients referred to one hypertension (HTN) center underwent 24-hour ambulatory blood pressure monitoring (ABPM) and one of four non-randomized, unattended AOBP protocols: a 3- or 5-minute delay with a 30 or 60-second interval, i.e., 3min/30sec/30sec, 3/60/60, 5/30/30 and 5/60/60 protocols. HTN was defined as systolic blood pressure ≥140 or diastolic blood pressure ≥90 mmHg. We compared differences in mean blood pressure and HTN classification between average AOBP and awake-time ABPM by t-tests and Fisher's exact test. Among 212 participants (mean 58.9 years, 61% women, 25% Black), there was substantial overlap in the probability distributions of awake-time ABPM and each of the three AOBP measures. Systolic blood pressure means were similar between the 5/60/60 and 3/30/30 protocols and 5/30/30 and 3/60/60 protocols. The 5/30/30 was associated with a higher proportion of systolic HTN, while the 3/60/60 protocol was associated with a higher proportion of diastolic HTN. There were no significant differences in systolic or diastolic HTN between 5/60/60 and 3/30/30 protocols with respect to awake-time ABPM. In this quality improvement study, the shortest AOBP protocol did not differ significantly from the longest protocol. The time savings of shorter protocols may improve AOBP adoption in clinical practice without meaningfully compromising accuracy.

Role of Artificial Intelligence (AI) in Clinical Interpretation of 24-Hour Ambulatory Blood Pressure Monitoring

Role of Artificial Intelligence (AI) in Clinical Interpretation of 24-Hour Ambulatory Blood Pressure Monitoring

The relationship between exercise-related hypertension and carotid artery intima media thickness and brachial artery endothelial function

Aims: Hypertension is one of the most common chronic diseases in the world. There are some non-invasive tests which are used to assess end organ damages in patients with hypertension. The purpose of this study is to show relationship between carotid artery intima media thickness (CIMT) and flow mediated dilatation (FMD) in patients with exercise induced hypertension (EIH). Methods: 73 healthy normotensive men and women, who are between 18 and 65 years of age, participated in this study. All patients underwent electrocardiography, echocardiography, 24-hour ambulatory blood pressure monitoring and symptom-limited treadmill testing before CIMT and FMD were measured with Doppler ultrasonography. CIMT and FMD values of both groups were statistically compared with each other. Results: Of a total of 73 individuals, 56 were evaluated as the patient group and 17 as the control group. Age, smoking rate, body mass index, resting and maximum blood pressure values, and ascending aorta diameter were significantly higher in the patient group (p=0.02 for smoking, p<0.01 for the rest). Right/left main CIMT, right/left bulbus IMT, and left ventricular diastolic dysfunction was significantly higher in the patient group (p<0.05 for all). In addition, the mean CIMT and mean FMD (%) values were significantly higher and lower, respectively, in the patient group compared to the control group. No difference was observed between the two groups in terms of right/left internal CIMT and passive smoking exposure. In addition, the mean values of CIMT and FMD (%) did not show a statistically significant difference according to hypertensive response stages and gender. Conclusion: CIMT and FMD are significantly associated with EIH. EIH should be evaluated as important risk factor for future hypertension and may cause asymptomatic end-organ damage. It can be easily assessed using CIMT and FMD.

Nocturnal blood pressure dipping and left ventricular hypertrophy among hypertensive outpatients in a Ghanaian hospital.

To investigate the association between the extent of nocturnal systolic blood pressure decline and left ventricular hypertrophy in patients with primary hypertension who were receiving antihypertensive drug therapy. This was a cross-sectional hospital-based study from November 2020 to March 2021. The study was conducted at the Polyclinic of Korle Bu Teaching Hospital, Ghana. Outpatients ≥18 years old with primary hypertension who were receiving antihypertensive drug therapy. Each participant underwent a 24-hour ambulatory blood pressure monitoring and a transthoracic echocardiogram. Left ventricular hypertrophy and the extent of mean systolic blood pressure decline during sleep. 180 participants were recruited, comprising 110 (61.1%) females. The participants' mean (±SD) age was 57.6 ± 11.0 years. 80% had a non-dipping blood pressure pattern, and 43.9% had left ventricular hypertrophy. Uncontrolled office blood pressure was an independent predictor of left ventricular hypertrophy in these patients (AOR 2.010, 95% CI 1.048-3.855, p=0.036); however, a non-dipping nocturnal systolic blood pressure status was not (AOR 1.849, 95% CI 0.850-4.022, p=0.121). 61.1% had abnormal left ventricular geometry, with concentric hypertrophy being the predominant geometric pattern. Left ventricular hypertrophy and non-dipping nocturnal blood pressure were common in these hypertensive Ghanaian patients on antihypertensive therapy. Left ventricular hypertrophy was associated with uncontrolled office blood pressure but not the extent of nocturnal systolic blood pressure declines during a single 24-hour ambulatory blood pressure recording. None declared.

Association of body composition with ambulatory blood pressure among Chinese youths

BackgroundFor youths, abnormalities in ambulatory blood pressure (ABP) patterns are known to be associated with increased cardiovascular disease risk and potential target organ damage. Body composition, including indicators such as lean mass index (LMI), fat mass index (FMI), and visceral fat level (VFL), plays a significant role in blood pressure (BP) regulation. However, little is known about the association between these body composition indicators and ABP. Therefore, the present study examined the association between these body composition indicators and BP among Chinese youths.MethodsA total of 477 college students aged 17 to 28 years old (mean ± Standard deviation = 18.96 ± 1.21) from a university in Changsha, Hunan Province, China, were included in this study. Body composition indicators were measured with a bioelectrical impedance body composition analyzer, and 24-hour ambulatory blood pressure monitoring (ABPM) was conducted. Multivariable logistic regression was performed to assess the relationship between body composition indicators and abnormal ABP.ResultsThe prevalence of abnormal BP, including 24-hour BP, daytime BP, nighttime BP, and clinic BP, were 4.8%, 4.2%, 8.6%, and 10.9%, respectively. After adjusting for potential covariates, LMI [abnormal 24-hour BP (OR = 1.85, 95%CI:1.31, 2.62), abnormal daytime BP (OR = 1.76, 95%CI:1.21, 2.58), abnormal nighttime BP (OR = 1.64, 95%CI:1.25, 2.14), abnormal clinic BP (OR = 1.84, 95%CI:1.38, 2.45)], FMI [abnormal 24-hour BP (OR = 1.20, 95%CI:1.02, 1.41), abnormal daytime BP (OR = 1.30, 95%CI:1.07, 1.57), abnormal nighttime BP (OR = 1.24, 95%CI:1.10, 1.39), abnormal clinic BP (OR = 1.42, 95%CI:1.22, 1.65)], and VFL [abnormal 24-hour BP (OR = 1.22, 95%CI:1.06, 1.39), abnormal daytime BP (OR = 1.29, 95%CI:1.10, 1.51), abnormal nighttime BP (OR = 1.24, 95%CI:1.12, 1.39), abnormal clinic BP (OR = 1.38, 95%CI:1.21, 1.57)] are positively linked to abnormal BP. Additionally, there were significant sex differences in the association between body composition and abnormal BP.ConclusionsOur findings suggested maintaining an individual’s appropriate muscle mass and fat mass and focusing on the different relations of males’ and females’ body composition is crucial for the achievement of appropriate BP profiles.

P060 A NOVEL NON-INVASIVE METHOD FOR ESTIMATING CENTRAL SYSTOLIC BLOOD PRESSURE USING AMBULATORY BLOOD PRESSURE MONITORING

Background and Objective: Central blood pressure (BP) holds superior prognostic value compared to peripheral BP in predicting cardiovascular events. Despite its significance, measuring central BP in outpatient settings is impractical. To address this limitation, our research group devised a novel non-invasive method for estimating central systolic blood pressure (cSBP) using peripheral data based on the equation proposed by Chemla et al. However, its validity remains uncertain. The objective was to assess the validity of our new non-invasive method for estimating cSBP by comparing it to a validated brachial oscillometric method. Methods: A cross-sectional study was conducted, involving 132 patients who underwent 24-hour ambulatory blood pressure monitoring (24-h ABPM). A total of 8,112 BP records were obtained. The cSBP was measured during 24-h ABPM using a Custo Screen 310 device (Custo, Ottobrunn, Germany), which has been validated. The cSBP was estimated using the formula: cSBP= MAP2/DBP, where MAP2 represents the estimated mean arterial pressure using the equation: MAP2=(Ts/T) × SBP + (Td/T) × DBP, where T, Ts, and Td denote the cardiac, systolic, and diastolic periods, respectively. The SBP indicate systolic blood pressure and DBP denote diastolic blood pressure. Ts was calculated as: Ts=0.2061+ (Age/2244) + (T/8.17). Results: Among the participants, 53.8% were men, with an average age of 55±16 years. The average height was 1.65±0.1 m, weight 74±12 kg, heart rate 71±12 bpm, SBP 125±19 mmHg, DBP 79±12 mmHg, and cSBP 120±19 mmHg. The agreement of cSBP between the new method and the brachial oscillometric method was very good. Bland-Altman plots revealed that the differences between the methods were randomly distributed along the mean difference line (Figure). Conclusions: The new non-invasive method to estimate cSBP from peripheral BP data, using MAP2 and cardiac periods, has been demonstrated to be valid. The equation, which allows for the estimation of cSBP without a pulse wave, could be easily implemented in conventional 24-h ABPM systems.

P167 DIFFERENCES IN PULSE WAVE VELOCITY ESTIMATED USING TOTAL ARTERIAL COMPLIANCE BETWEEN SUBTYPES OF ARTERIAL HYPERTENSION

Background and Objective: Different clinical phenotypes of arterial hypertension (AH) are identified through current oscillometric blood pressure (BP) measurements. Recently, our group described hemodynamic characteristics of AH subtypes utilizing 24-hour ambulatory blood pressure monitoring (24-h ABPM). It remains unclear whether differences in PWV exist among AH subtypes, which could potentially enhance diagnostic accuracy and guide antihypertensive treatment selection. The objective was to assess the relationship between PWV, estimated using Ct, and AH subtypes. Methods: A cross-sectional study was conducted, involving 13,027 untreated patients referred for 24-h ABPM. PWV was estimated using a novel method based on Ct, derived from BP and heart rate measurements obtained during 24-h ABPM. This estimation method was developed based on the relationship between Ct and PWV as described by Vardoulis et al., utilizing the Bramwell-Hill theory and experimental research. The formula used for PWV estimation was PWV = √(36.7/(Ct/(log[age]))). Results: Among the participants, 46.5% were men, with an average age of 50.2±14.1 years and a body mass index of 27.1±4.1 kg/m2. Isolated systolic hypertension (ISH) (3.9%) exhibited the highest arterial stiffness, with the highest PWV (10.2±1.4 m/s) and pulse pressure (PP) (60.0±6.6 mmHg), and the lowest Ct (0.67±0.16 mL/mmHg). In contrast, isolated diastolic hypertension (IDH) (26.3%) showed the lowest PWV (7.9±0.8 m/s) and PP (40.6±3.6 mmHg), and the highest Ct (1.01±0.18 mL/mmHg). As Ct decreased, PWV increased. Thus, PWV based on Ct from 24-hour ABPM showed clear differences between AH subtypes (ANOVA; p value < 0.001) (Figure). Conclusions: PWV is related with AH subtypes, exhibiting a progression from IDH to ISH. Patients with IDH typically have the lowest PWV, whereas those with divergent systolic-diastolic hypertension (D-SDH) and ISH have the highest PWV values. These findings underscore the significance of Ct in determining PWV values and carry diagnostic and prognostic implications concerning arterial function across various AH subtypes.

Abstract P313: Diastolic to Systolic Arterial stiffening has Greater Prognostic Power than Diastolic Stiffness in 20-60 Years Old Patients Undergoing 24-Hour Ambulatory Blood Pressure Monitoring

The 24-hour ambulatory pulse pressure (PP), can be expressed as a sum of two ‘PP components’: ‘elastic’ PP (elPP) and ‘stiffening’ PP (stPP) associated, respectively, with arterial stiffness at the diastolic pressure (somewhat equivalent to pulse wave velocity being measured in the diastole), and the relative stiffness change from the diastolic- to the systolic pressure. Here we assess and compare the hazard ratio (HR) of elPP and stPP for outcomes in a large cohort of young and middle-age patients. We analyzed adequate quality 24h ambulatory blood pressure monitoring records from the Spanish Ambulatory Blood Pressure Registry. For standard deviation(SD), K=SD(SBP)/SD(DBP), elPP=PPxln(K)/(K-1) and stPP=PP-elPP. HRs were determined for age 20-40, 41-50, and 51-60 years, using Cox regression models applied to standardized elPP & stPP (combined), adjusted for age, sex, BMI, smoking status, diabetes, dyslipidemia, mean DBP, pulse rate, SD(SBP), antihypertensive treatment, and previous cardiovascular disease (CVD). The endpoints were total mortality, and death from CVD, or coronary heart disease (CHD). Of the 24,260 patients mean age (SD) 48.0(9.0) years, 34% male] 845 deaths occurred during period of 9.6(2.2) years. The Table shows that mean elPP slightly decreased from younger to older age, while stPP strongly increased. At age 41-60 years the adjusted HRs of stPP appeared significant and greater than those of elPP for almost all cases. The most contributing adjustors in the Cox regression were smoking, for all age classes, and sex for age over 40 years. Thus, the stiffening component may have greater predictive power than the elastic component for total mortality, and CVD&CHD death, in middle-age patients.

P004 BODY MASS INDEX IS RELATED TO SUBTYPES OF ARTERIAL HYPERTENSION IN CHILDREN

Background and Objective: Arterial hypertension (AH) subtypes in the pediatric population may represent distinct pathophysiological subsets, potentially allowing for more targeted interventions and improved blood pressure (BP) management. Emerging evidence suggests that various hemodynamic mechanisms may underlie hypertension development across different age groups. Moreover, overweight and obesity, are closely linked to hypertension and other risk factors. Therefore, this study aims to investigate the relationship between body mass index (BMI) and (AH) subtypes in the pediatric population. Methods: A cross-sectional study was conducted, involving 195 records from 189 children referred to an outpatient cardiology center due to suspected BP abnormalities. Each participant underwent 24-hour ambulatory blood pressure monitoring (24-h ABPM) using a device validated. Demographic, clinical, and anthropometric data were collected. The American Heart Association (2022) criteria were utilized to ensure accurate 24-h ABPM recordings and to classify AH subtypes based on average BP, including: i) isolated diastolic hypertension (IDH); ii) non-divergent systolic-diastolic hypertension (ND-SDH) (pulse pressure [PP]<50 mmHg); iii) divergent systolic-diastolic hypertension (D-SDH) (PP>50 mmHg); and iv) isolated systolic hypertension (ISH). BMI Z-Score was calculated using Colombian reference tables, and nutritional status was determined based on World Health Organization recommendations. Results: Among the participants, 46.0% were male, with a distribution of nutritional status showing 3% underweight, 37% normal weight, 30% overweight, and 30% obese. The average age was 12.3±3.0 years (range: 5-17 years). 24-h ABPM records revealed that 34.0% had normotension, 33.0% had IDH, 16.0% had ND-SDH, 13.0% had D-SDH, and 3% had ISH. The ANOVA test indicated significant differences in BMI Z-Score values among AH subtypes (P value <0.001) (Figure). Conclusions: BMI is related with AH subtypes in children. Specifically, BMI tends to be higher in D-SDH and ISH, which could be characterized by a hyperdynamic state marked by increased activity of the sympathetic nervous system. This finding may help to elucidate the pathophysiology of hypertension in obese children.

O56 NIGHTTIME BLOOD PRESSURE REFERENCE VALUES FOR AMBULATORY BLOOD PRESSURE MONITORING AND THEIR RELATIONSHIP WITH AGE

Background and Objective: Nocturnal hypertension is characterized by elevated blood pressure (BP) levels during sleep (systolic blood pressure [SBP]>120 mmHg or diastolic blood pressure [DBP]>70 mmHg) as measured by 24-hour ambulatory blood pressure monitoring (24-h ABPM) (ESH 2023 guidelines). With aging, there is a gradual decline in renal function and vascular health, leading to changes in BP patterns. This study seeks to evaluate the necessity of age-specific cutoff points in defining hypertension, particularly during nocturnal hours. Methods: A cross-sectional study was conducted, involving 3,220 patients without hypertension, defined by 24-hour BP values, who were not using any antihypertensive medications and were referred for 24-h ABPM. Patients with a body mass index (BMI) ≥30 kg/m2 were excluded. The sleep period was defined as spanning from midnight to 6 am. Reference percentiles were established and juxtaposed with standard references. To determine the significance of age-specific cutoff points for defining nocturnal hypertension, the ESH 2023 reference was compared with the 95th percentile (P95) for age. Results: Among the participants, 64.6% were female, with an average age of 51.0±15.0 years, BMI of 25.0±2.7 kg/m2, nocturnal SBP of 106.4±9.0 mmHg (P95=121.8 mmHg), and nocturnal DBP of 66.0±5.0 mmHg (P95=74.3 mmHg). Normal distribution was observed for both SBP and DBP (Jarque Bera test). Nocturnal SBP exhibited a “J” shaped curve concerning age, whereas the average DBP remained relatively stable. Significant differences were noted for SBP across different age groups (P value <0.00001). Proposed cutoff points for mean nocturnal SBP were suggested as follows: i) P95 <60 years=120 mmHg; ii) P95 60-70 years=125 mmHg; and iii) P95 >70 years=130 mmHg (Figure). A reference of 75 mmHg was proposed as the cutoff point for mean nocturnal DBP. Conclusions: The study highlights age-related variations in the P95 of mean nocturnal SBP, while DBP remains relatively stable across age groups. Consequently, we propose new cutoff points for defining these parameters.

P165 HEMODYNAMIC PROFILES OF ISOLATED DIASTOLIC HYPERTENSION IN AMBULATORY BLOOD PRESSURE MONITORING

Background and Objective: Isolated diastolic hypertension (IDH) is a prevalent form of high blood pressure (BP), especially among young individuals. Yet, its association with cardiovascular disease risk and the necessity of treatment remain subjects of ongoing debate. Our research endeavors to elucidate hemodynamic profiles using a non-invasive method applied to 24-hour ambulatory blood pressure monitoring (24-h ABPM). However, uncertainty persists regarding whether distinct hemodynamic profiles exist within IDH patients, considering they are characterized by normal total arterial compliance (Ct). This study aims to shed light on potential variations in hemodynamics within the IDH population, providing valuable insights for personalized treatment. Methods: A cross-sectional study was conducted, involving 7,202 patients referred to an outpatient cardiology center for suspected arterial hypertension. These patients underwent 24-h ABPM. The study included individuals over 18 years old without a prior diagnosis of hypertension and not taking antihypertensive medication. Two groups were included: those with IDH, defined as diastolic blood pressure >80 mmHg (24-h ABPM), and those with normotension. Hemodynamic parameters were estimated using a published method to estimate Ct. Silhouette analysis determined the number of underlying groups within the IDH cohort, while cluster analysis classified these subgroups. Results: Among the participants, 59.0% were female, with an average age of 49.0±14.0 years. Of the total patients included, 3,424 (47.5%) had isolated diastolic hypertension (IDH). Silhouette analysis effectively distinguished two groups. Group IDH-1 exhibited normal Ct and systemic vascular resistance (SVR), elevated heart rate (HR), and higher cardiac index (CI) (P value <0.001). Conversely, group IDH-2 demonstrated high Ct and SVR, lower HR, and CI (P value <0.001) (Table). Conclusions: The delineation of two distinct hemodynamic profiles within IDH is significant. The first group demonstrates a cardiogenic hypertension profile, indicated by elevated CI, whereas the second group presents a profile characterized by heightened SVR. These contrasting hemodynamic patterns offer valuable insights for tailoring treatment strategies to individual patient needs. Table. Comparison of hemodynamic variables between normotensives (NT) and two isolated diastolic hypertension (IDH) profile, utilizing ANOVA for statistical analysis.

Abstract P167: Sex Dependent Associations of the Gut Microbiota with Hypertension – A Prospective Cohort

Background: Whilst there is emerging evidence that the associations of the gut microbiota (GM) with hypertension differ between sexes, it remains uncertain whether the GM 1) is altered with antihypertensive-use, 2) can predict blood pressure (BP) trajectories, and 3) whether these associations are also sex-dependent. We therefore aimed to determine the sex-dependent associations of the GM with baseline hypertensive state in untreated versus treated participants and BP changes over time. Methods: A total of 451 community-dwelling middle-aged Hong Kong Chinese without symptomatic cardiovascular diseases were recruited (50% men, 14% on antihypertensive agents, mean age, 54.6±6.5 years). Shotgun metagenomic sequencing of stool samples and 24-hour ambulatory blood pressure monitoring (ABPM) were performed. The 24hr-ABPM was repeated on 139 returned subjects after 4 years. Statistical analysis was conducted with 4 covariate models that include age, sex, menopause status, body mass index (BMI), smoking, fasting glucose, triglyceride, cholesterol, sodium intake, and fatty liver status. Results: Amongst the 389/451 subjects not on antihypertensive agents, 167/389 (42.9%) had newly diagnosed hypertension at baseline. Females drove the significantly different b-diversity of the GM composition ( p <0.01) between the normotensives and hypertensives in the baseline study. Multiple GM species were significantly associated with hypertension. In sex stratified analysis, Faecalimonas umbilicate was significantly enriched in hypertensive females while Roseburia sp Am16-25 and Eubacterium ramulus were enriched in hypertensive males (all p <0.05-0.01). When comparing the 62 treated and 167 nontreated hypertensive subjects, the GM abundance, a-, and b-diversity were not significantly different. However, there were significant GM species associated with the use of antihypertensive medication. Notably, Lachnospiraceae bacterium and Flavonifractor plautii were significantly enriched in treated and untreated individuals, respectively (all p <0.05-0.001). During a mean follow up of 51.2±4.5 months, 73.2% of the 71 untreated subjects remained normotensive and were associated with enriched Bacteroides uniformis in their baseline metagenomic data under models adjusted for age, sex, and BMI. Conclusion: The GM displayed sex-dependent associations with hypertension within untreated and treated individuals and can potentially predict BP trajectory changes within a Chinese population.

Abstract P312: Comparing Activity Logs in 24-hour Ambulatory Blood Pressure Monitoring

Background: Growing evidence suggests that activities during ambulatory blood pressure monitoring (ABPM) may affect measurement. While activity logs are often used to characterize context of measurements, there is little evidence to inform strategies to optimize the collection of these data from patients. Objective: To compare different log formats and their impact on data collection from activity logs of events occurring during ABPM. Methods: We performed a quality improvement project in our Hypertension Center using three different types of 24-hour ABPM logs (unstructured, semi-structured, and structured). Each log asked patients to record their daily activities including sleep, meals, physical activity, pain or other symptoms, medications, stress, caffeine, and tobacco use. The structured logs requested patients document activities with check boxes, the unstructured logs requested documentation with free text, and the semi-structured log combined check boxes and free text. Over a 12-month period, patients received one of the three versions of the ABPM logs in an alternating non-randomized schedule. We used linear regression models with adjustments for age, sex, and Black race to determine the association between items reported and log structure. Results: Between September 2022-2023, patients returned 47 unstructured, 26 semi-structured, and 31 structured logs (N=104). Patients were an average age of 58.9 years (SD, 17), 63% female and 23% Black. Compared with the unstructured log, the semi-structured log was associated with frequent reports of physical activity (0.05, P = 0.03), while the structured log was associated with more reports of pain (0.03, P =0.037) and stress (0.03, P =0.01). Compared to the semi-structured log, the structured log was associated with more reports of stress (0.03; P =0.032) . Discussion: In this quality improvement project of patients undergoing ABPM, adding structure to the log increased reporting of clinically relevant information related to pain and stress. Whether these data are related to changes in blood pressure should be a focus of subsequent work.

P214 PREDICTION OF AMBULATORY BRACHIAL CUFF-BASED OSCILLOMETRIC PULSE WAVE VELOCITY USING A NOVEL METHOD FOR ESTIMATING TOTAL ARTERIAL COMPLIANCE

Background and Objective: Total arterial compliance (Ct) serves as a critical determinant of arterial hemodynamics, providing insights into the mechanical and structural characteristics of large arteries and influencing ventricular-arterial coupling. To estimate Ct, we developed a method utilizing data from 24-hour ambulatory blood pressure monitoring (24-h ABPM) recordings. Our objective is to evaluate the reliability of Ct in estimating oscillometric pulse wave velocity (oPWV), with the potential to eliminate the requirement for additional oPWV measurements. Methods: A cross-sectional study was conducted, involving 162 patients who underwent 24-h ABPM, resulting in a total of 8,113 blood pressure (BP) recordings. oPWV was measured during 24-h ABPM using a Custo Screen 310 device (Custo, Ottobrunn, Germany), which has been validated. Ct was estimated employing a two-element Windkessel model based on mean systolic pressure. The formula utilized for Ct estimation was Ct/BSA= (38/PPth)×(4/5)×(Td/T)-(3/7), where BSA denotes body surface area, Td represents diastolic time, T signifies the cardiac period, and PPth denotes theoretical pulse pressure. A linear regression model (LRM) was developed to estimate oPWV from Ct. Results: Among the participants, 55.1% were men, with an average age of 55.7±16.2 years and a body mass index of 27.4±3.7 kg/m2. The analyzed records revealed an average systolic blood pressure of 125.6±18.7 mmHg, diastolic blood pressure of 79.5±12.2 mmHg, heart rate of 71.0±12.2 beats per minute, Ct of 0.9±0.3 mL/mmHg, and oPWV of 7.2±1.8 m/s. The best predictive model (R2=0.42; r=0.65) for oPWV was based on the ratio of systolic time (Ts) to Ct as follows: oPWV=3.3 × 6.0 ×[Ts/(Ct/BSA)]. Indexed Ct demonstrated an inverse relationship with oPWV (Figure). Residuals analysis confirmed compliance with assumptions. Conclusions: The Ts/Ct ratio inversely predicts oPWV, indicating an inverse relationship between Ct and oPWV in this population. These findings suggest that estimated Ct has the potential to replace oPWV in clinical practice for cardiovascular risk stratification.

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.

P006 AGE-RELATED DIFFERENCES IN PULSE PRESSURE AND AMBULATORY ARTERIAL STIFFNESS INDEX MEASURED BY AMBULATORY BLOOD PRESSURE MONITORING

Background: Hypertension is a prevalent public health concern, particularly affecting older adults. Beyond optimal blood pressure (BP) control, ambulatory blood pressure monitoring (ABPM) offers valuable insights into additional cardiovascular parameters like pulse pressure (PP), arterial stiffness index (AASI), and heart rate (HR). Studies have shown that PP correlates with systolic blood pressure and predicts cardiovascular mortality in older adults (1). Furthermore, AASI, a readily measured indirect marker of arterial stiffness, has demonstrated predictive power for cardiovascular mortality (2). Objective: This study investigates the differences in PP, AASI, and HR measured through ABPM across age groups (younger than 50 years, 50-65 years, and over 65 years) and between genders. Methods: This cross-sectional descriptive study analyzed ABPM data collected between 2018 and 2024 from a cardiovascular institution in Colombia. Mean systolic and diastolic BP, heart rate, AASI, and PP were evaluated based on age and sex. Normality testing was performed using the Kolmogorov-Smirnov test. For continuous variables, parametric ANOVA tests compared values across age groups. Categorical variables were analyzed using Chi-square tests. Results: A total of 150 patients participated in the study, with females comprising 76 (50.7%) of the group. The age distribution was: 23.3% younger than 50 years, 41.3% between 50-65 years, and 34.0% over 65 years old. Significant differences were found in diastolic BP, PP, AASI, and HR between the age groups. Importantly, no significant differences were observed in these measures based on gender, nor in systolic BP by age or sex. Conclusions: Our findings align with previous research, demonstrating an increase in PP and AASI with advancing age. Given its widespread availability, ABPM offers a valuable tool. Incorporating additional parameters like PP and AASI provides further information potentially linked to cardiovascular mortality risk. 1. Glynn RJ et al. Pulse Pressure and Mortality in Older People. Arch Intern Med. 2000;160(18):2765–2772. 2. Li, Y. et al. Ambulatory arterial stiffness index derived from 24-hour ambulatory blood pressure monitoring. Hypertension, 47(3), 359–364.