Mean arterial pressure estimated by brachial pulse wave analysis and comparison with currently used algorithms

Non-Invasive Assessment of Coronary Microvascular Dysfunction Using Vascular Deformation-Based Flow Estimation

OBJECTIVE

Non-invasive computation of the index of microcirculatory resistance from coronary computed tomography angiography (CTA), referred to as IMR[Formula: see text], is a promising approach for quantitative assessment of coronary microvascular dysfunction (CMD). However, the computation of IMR[Formula: see text] remains an important unresolved problem due to its high requirement for the accuracy of coronary blood flow. Existing CTA-based methods for estimating coronary blood flow rely on physiological assumption models to indirectly identify, which leads to inadequate personalization of total and vessel-specific flow.

METHODS

To overcome this challenge, we propose a vascular deformation-based flow estimation (VDFE) model to directly estimate coronary blood flow for reliable IMR[Formula: see text] computation. Specifically, we extract the vascular deformation of each vascular segment from multi-phase CTA. The concept of inverse problem solving is applied to implicitly derive coronary blood flow based on the physical constraint relationship between blood flow and vascular deformation. The vascular deformation constraints imposed on each segment within the vascular structure ensure sufficient individualization of coronary blood flow.

RESULTS

Experimental studies on 106 vessels collected from 89 subjects demonstrate the validity of our VDFE, achieving an IMR[Formula: see text] accuracy of 82.08 %. The coronary blood flow estimated by VDFE has better reliability than the other four existing methods.

CONCLUSION

Our proposed VDFE is an effective approach to non-invasively compute IMR[Formula: see text] with excellent diagnostic performance.

SIGNIFICANCE

The VDFE has the potential to serve as a safe, effective, and cost-effective clinical tool for guiding CMD clinical treatment and assessing prognosis.

Assessing the Accuracy of Systolic Aortic Pressure Estimation From a Brachial Cuff Alone: A Comparison With Radial Tonometry

BACKGROUND

A novel method for estimating central systolic aortic pressure (cSAP) has emerged, relying solely on the peripheral mean (MBP) and diastolic (DBP) blood pressures. We aimed to assess the accuracy of this Direct Central Blood Pressure estimation using cuff alone (DCBPcuff = MBP2/DBP) in comparison to the use of a generalized transfer function to derive cSAP from radial tonometry (cSAPtono).

METHODS

This retrospective analysis involved the International Database of Central Arterial Properties for Risk Stratification (IDCARS) data (Aparicio et al., Am J Hypertens 2022). The dataset encompassed 10,930 subjects from 13 longitudinal cohort studies worldwide (54.8% women; median age 46.0 years; office hypertension: 40.1%; treated: 61.0%), documenting cSAPtono via SphygmoCor calibrated against brachial systolic BP (SBP) and DBP. Our analysis focused on aggregate group data from 12/13 studies (89% patients) where a full BP dataset was available. A 35% form factor was used to estimate MBP = (DBP + (0.35 × (SBP-DBP)), from which DCBPcuff was derived. The predefined acceptable error for cSAPtono estimation was set at ≤ 5 mm Hg.

RESULTS

The cSAPtono values ranged from 103.8-127.0 mm Hg (n = 12). The error between DCBPcuff and cSAPtono was 0.2 ± 1.4 mm Hg, with no influence of the mean. Errors ranged from -1.8 to 2.9 mm Hg across studies. No significant difference in errors was observed between BP measurements obtained via oscillometry (n = 9) vs. auscultation (n = 3) (P = 0.50).

CONCLUSIONS

Using published aggregate group data and a 35% form factor, DCBPcuff demonstrated remarkable accuracy in estimating cSAPtono, regardless of the BP measurement technique. However, given that individual BP values were unavailable, further documentation is required to establish DCBPcuff's precision.

Evaluating the relative importance of different blood pressure indices in screening for NAFLD: a survey report based on a health examination population

Objective

While hypertension is a well-recognized risk factor for non-alcoholic fatty liver disease (NAFLD), the specific roles of various common blood pressure measurements [diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), mean arterial pressure (MAP)] in detecting NAFLD and evaluating the associated risk in adults remain unclear.

Methods

A retrospective analysis was conducted on 14,251 adult participants undergoing health screenings in the NAfld in the Gifu Area, Longitudinal Analysis project (NAGALA). Following the Z-transformation of the independent variables, we evaluated the relationships between the four blood pressure indices and NAFLD through multivariable logistic regression models. This analysis documented the odds ratio (OR) and 95% confidence interval (CI) for each standard deviation (SD) increase. Additionally, the effectiveness of these indices in identifying NAFLD was comparatively analyzed using receiver operating characteristic (ROC) curves.

Results

After adequately adjusting for confounders, all blood pressure indices except PP showed a positive correlation with NAFLD. For each SD increment, MAP had the strongest association with NAFLD compared to SBP and DBP. This finding was confirmed in populations without exercise habits, under 60 years of age, with normal blood pressure, and in non-obese groups. Furthermore, based on ROC analysis, MAP was found to have the highest accuracy in identifying NAFLD compared to the other three blood pressure indices.

Conclusion

Among the four blood pressure indices evaluated, MAP demonstrates the greatest efficacy in identifying NAFLD and assessing its associated risk. These findings underscore the potential of MAP as the most promising blood pressure index for screening NAFLD.

Myocardial oxygen supply and demand imbalance predicts mortality in older nursing home residents: The PARTAGE study

BACKGROUND

A mismatch between myocardial oxygen supply and demand is the most common cause of ischemic myocardial injury in older persons. The subendocardial viability ratio (SEVR) can usefully estimate the degree of myocardial perfusion relative to left-ventricular workload. The aim of the present study was to evaluate the ability of SEVR to predict long-term mortality in the older population. Additionally, we aimed to identify the SEVR cutoff value best predicting total mortality.

METHODS

This is a multicenter, longitudinal study involving a large population of individuals older than 80 years living in nursing homes. Patients with cancer, severe dementia, and very low level of autonomy were excluded from the study. Participants were monitored for 10 years. Adverse outcomes were recorded every 3 months from inclusion to the end of the study. SEVR reflects the balance between subendocardial oxygen supply and demand, and was estimated non-invasively by analyzing the carotid pressure waveform recorded by applanation arterial tonometry.

RESULTS

A total of 828 people were enrolled (mean age: 87.7 ± 4.7 years, 78% female). 735 patients died within 10 years and 24 were lost to follow-up. SEVR was inversely associated with mortality at univariate Cox-regression model (risk ratio, 0.683 per unit increase in SEVR; 95% confidence interval (CI) [0.502-0.930], p = 0.015) and in a model including age, sex, body mass index, Activity of Daily Living index and Mini-Mental State Examination score (risk ratio, 0.647; 95% CI [0.472-0.930]). The lowest tertile of SEVR was associated with higher 10-years total mortality than the middle (p < 0.001) and the highest (p < 0.004) tertile. A SEVR cutoff value of 83% was identified as the best predictor of total mortality.

CONCLUSIONS

SEVR may be considered as a marker of "cardiovascular frailty." An accurate non-invasive estimation of SEVR could be a useful and independent parameter to assess survival probability in very old adults.

TRIAL REGISTRATION

NCT00901355, registered on ClinicalTrials.gov website.

Lower-Limb Perfusion and Cardiovascular Physiology Are Significantly Improved in Non-Healthy Aged Adults by Regular Home-Based Physical Activities-An Exploratory Study

Common daily activities including walking might be used to improve cardiovascular health in the presence of disease. Thus, we designed a specific home-based physical activity program to assess cardiovascular indicators in an older, non-active, non-healthy population. Ten participants, with a mean age of 62.4 ± 5.6 years old, were chosen and evaluated twice-upon inclusion (D0), and on day 30 (D30)-following program application. Perfusion was measured in both feet by laser Doppler flowmetry (LDF) and by polarised spectroscopy (PSp). Measurements were taken at baseline (Phase 1) immediately after performing the selected activities (Phase 2) and during recovery (Phase 3). Comparison outcomes between D0 and D30 revealed relevant differences in Phase 1 recordings, namely a significant increase in LDF perfusion (p = 0.005) and a significant decrease in systolic blood pressure (p = 0.008) and mean arterial pressure (MAP) (p = 0.037). A correlation between the increase in perfusion and the weekly activity time was found (p = 0.043). No differences were found in Phase 2, but, in Phase 3, LDF values were still significantly higher in D30 compared with D0. These simple activities, regularly executed with minimal supervision, significantly improved the lower-limb perfusion while reducing participants' systolic pressure and MAP, taken as an important improvement in their cardiovascular status.

Value and Variability of Pulse Shape Indicator for Estimating Mean Arterial Pressure in the Radial and Femoral Arteries

BACKGROUND

The form factor (FF) is a pulse shape indicator that corresponds to the fraction of pulse pressure added to diastolic blood pressure to estimate the time-averaged mean arterial pressure (MAP). Our invasive study assessed the FF value and variability at the radial and femoral artery levels and evaluated the recommended fixed FF value of 0.33.

METHODS AND RESULTS

Hemodynamically stable patients were prospectively included in 2 intensive care units. FF was documented at baseline and during dynamic maneuvers. A total of 632 patients (64±16 years of age, 66% men, MAP=81±14 mm Hg) were included. Among them, 355 (56%) had a radial catheter and 277 (44%) had a femoral catheter. The FF was 0.34±0.06. In multiple linear regression, FF was influenced by biological sex (P<0.0001) and heart rate (P=0.04) but not by height, weight, or catheter location. The radial FF was 0.35±0.06, whereas the femoral FF was 0.34±0.05 (P=0.08). Both radial and femoral FF were higher in women than in men (P<0.05). When using the 0.33 FF value to estimate MAP, the error was -0.4±4.0 mm Hg and -0.1±2.9 mm Hg at the radial and femoral level, respectively, and the MAP estimate still demonstrated high accuracy and good precision even after changes in norepinephrine dose, increase in positive end-expiratory pressure level, fluid administration, or prone positioning (n=218).

CONCLUSIONS

Despite higher FF in women and despite interindividual variability in FF, using a fixed FF value of 0.33 yielded accurate and precise estimations of MAP. This finding has potential implications for blood pressure monitoring devices and the study of pulse wave amplification.

Mean arterial pressure and mortality in patients with heart failure: a retrospective analysis of Zigong heart failure database

BACKGROUND

It is commonly observed that a higher target of mean arterial pressure (MAP) is in previous studies. This study assessed the association of MAP with short-term mortality in heart failure (HF) patients.

METHODS

A retrospective cohort study was conducted by using data from Hospitalized patients with heart failure: integrating electronic healthcare records and external outcome database (v1.2 ). The characteristic of patients was described by 3 groups of MAP: below 80 mmHg, 80-100 mmHg, and above 100 mmHg. Univariate and multivariate logistic regression analyses were used to assess the relevance between MAP and all-cause mortality within 28 days and 6 months. For assessing the effect of multiple variables on patient survival time, 28-day and 6-month, Kaplan-Meier survival analysis and Forest plot were performed.

RESULTS

The overall cohort comprised 2008 patients divided by MAP into 3 groups, each group had 344 (17.1%), 938 (46.7%), and 726 (36.2%) patients. Patients in MAP < 80 mmHg group had higher mortality than MAP 80-100 mmHg and MAP ≥ 100 mmHg in 28 days(3.8% versus 1.6% versus 1.2%) and in 6 months (4.9% versus 2.5% versus 2.3%). Univariate analysis showed that MAP as a continuous variate was associated with 28-day (OR was 0.98, 95% CIs: 0.96-0.99, P  = 0.011) and 6-month mortality (OR was 0.98, 95% CIs: 0.97-1, P  = 0.021) in HF patients. Model 4 put into multivariate logistic regression analyses showed MAP 80-100 mmHg (OR was 0.13, 95% CIs: 0.02-0.8, P  = 0.027) stably associated with 28-day and 6-month mortality after adjusted covariable. Kaplan-Meier survival curves revealed a higher survival rate in the MAP ≥ 80 mmHg group than in the MAP < 80 mmHg group. The forest plot showed the stable effect of MAP ≥ 80 mmHg compared with MAP < 80 mmHg, the interaction analysis had no statistical significance effect between the two groups of MAP and multi-variable.

CONCLUSION

It is indicated that MAP was independently associated with 28-day, 6-month all-cause mortality of HF patients, and compared with MAP < 80 mmHg, MAP ≥ 80 mmHg had a lower risk of 28-day, 6-month all-cause mortality of patients with HF.

Association of mean arterial pressure with non-alcoholic fatty liver disease: results from the NAGALA study

Objective

Several recent reports have suggested the use of mean arterial blood pressure (MAP) to assess/predict the risk of developing atherosclerosis, chronic kidney disease, diabetes, metabolic syndrome, and poor prognosis in a variety of cardiovascular and cerebrovascular diseases. The current study aimed to investigate the association of MAP with non-alcoholic fatty liver disease (NAFLD) and to explore the differences in this association across populations.

Methods

This study used data from the NAGALA study from 1994 to 2016. MAP was calculated as 1/3 systolic blood pressure (SBP) + 2/3 diastolic blood pressure (DBP). Restricted cubic spline (RCS) and logistic regression models were used to examine the correlation of MAP with NAFLD.

Results

The study population was 14,251 general people undergoing health screening, with a median (interquartile range) age of 42 (36-50) years; among them, 48% were women, and 2,507 (17.59%) were diagnosed with NAFLD. After fully controlling for confounders in the current dataset, MAP was positively and non-linearly associated with NAFLD [(odds ratios (ORs): 1.39, 95% confidence intervals (CIs): 1.15, 1.68); P for non-linearity = 0.024]; the dose-response curve showed that there was a transient saturation effect interval when MAP was between 85 and 95 mmHg, where the risk of NAFLD was neither increased nor decreased. The results of the stratified analysis showed that the risk of NAFLD associated with MAP appeared to be influenced only by age (P-interaction = 0.002), but not by sex, body mass index (BMI), habits of exercise, drinking status, or smoking status (P-interaction > 0.05); further age-stratified RCS analysis showed that the non-linear association between MAP and NAFLD in the young and middle-aged and the middle-aged and elderly populations was consistent with the results of the whole population, whereas, in the elderly population, a U-shaped curve association between MAP and NAFLD was observed, with both low and high MAP increasing the risk of NAFLD.

Conclusion

In the general population, MAP was positively and non-linearly associated with NAFLD, and this association only differed significantly by age, but not by sex, BMI, habits of exercise, drinking status, and smoking status.

Prospective study of the association between chronotype and cardiometabolic risk among Chinese young adults

BACKGROUND

The association of evening chronotype with cardiometabolic disease has been well established. However, the extent to which circadian rhythm disturbances independently result in risk remains unclear. This study aimed to investigate the cross-sectional and prospective longitudinal associations between chronotype and cardiometabolic risk among Chinese young adults.

METHODS

From April to May 2019, a total of 1 135 young adults were selected to complete the self-administered questionnaire, and 744 fasting blood samples were collected to quantify cardiometabolic parameters. From April to May 2021, 340 fasting blood samples were collected to quantify cardiometabolic parameters. The Morning and Evening Questionnaire 5 (MEQ-5) was used to assess chronotype. The cardiometabolic (CM)-risk score was the sum of standardized Z scores based on gender for the 5 indicators: waist circumference (WC), mean arterial pressure (MAP), triglyceride (TG), homeostasis model assessment for insulin resistance (HOMA-IR), and high-density lipoprotein cholesterol (HDL-C), where the HDL-C is multiplied by-1. The generalized linear model was used to determine the cross-sectional and prospective longitudinal associations between chronotype and each cardiometabolic parameter.

RESULTS

Cross-sectional association analysis showed that lower MEQ-5 scores were correlated with higher fasting insulin (β=-1.420, 95%CI: -2.386~-0.453), higher HOMA-IR (β=-0.301, 95%CI: -0.507~-0.095), and higher CM risk score (β=-0.063, 95%CI: -0.122~-0.003), even after adjustment for covariates. Prospective longitudinal association analysis also showed that lower MEQ-5 scores were associated with 2 years later higher fasting glucose (β=-0.018, 95%CI: -0.034~-0.003), higher fasting insulin (β=-0.384, 95%CI: -0.766~-0.003), higher HOMA-IR (β=-0.089, 95%CI: -0.176~-0.002), and higher CM-risk score (β=-0.109, 95%CI: -0.214~-0.003) after adjustment for covariates.

CONCLUSIONS

Evening chronotype was significantly correlated with higher CM risk among young adults. Our findings suggest that biologically and socially affected sleep timing misalignment is a contributing factor to cardiovascular disease risk.

Mean arterial pressure trajectory with premature cardiovascular disease and all-cause mortality in young adults: the Kailuan prospective cohort study

Background

The association between mean arterial pressure (MAP) trajectory in young adults and risk of cardiovascular diseases (CVD) and all-cause mortality is not well-characterized. The objective of this study was to investigate the effects of different MAP trajectory on the risk of CVD and all-cause mortality among the young.

Methods

In the Kailuan cohort study, 19,171 participants aged 18-40 years were enrolled without CVD (including myocardial infarction, stroke, atrial fibrillation and heart failure). The potential hybrid model was used to fit different trajectory patterns according to longitudinal changes of MAP. Hazard ratios and 95% confidence intervals for risk of CVD and all-cause mortality were analyzed using Cox proportional hazard regression models for participants with different trajectories.

Results

Five distinct MAP trajectories were identified during 2006-2013. Each of the trajectories was labelled as low-stable, middle-stable, decreasing, increasing, or high-stable. With the low-stable trajectory group as the reference, the multivariate adjusted HR (95%CI) of CVD for the middle-stable, decreasing, increasing and high-stable groups were 2.49 (1.41-4.40), 5.18 (2.66-10.06), 5.91 (2.96-11.80) and 12.68 (6.30-25.51), respectively. The HR (95%CI) for all-cause deaths were 1.27 (0.84-1.94), 2.01 (1.14-3.55), 1.96 (1.04-4.3.72), and 3.28 (1.69-6.37), respectively.

Conclusion

In young adults, MAP trajectories were associated with the risk of CVD or all-cause mortality and increasing MAP trajectories within the currently designated "normal" range may still increase the risk for CVD.

Relationship between measures of adiposity, blood pressure and arterial stiffness in adolescents. The MACISTE study

OBJECTIVE

Children and adolescents with adiposity excess are at increased risk of future cardiovascular (CV) disease. Fat accumulation promotes the development of elevated blood pressure (BP) and arterial stiffness, two main determinants of CV risk which are strongly inter-related. We aimed at investigating whether the association between overweight and arterial stiffness, taken at different arterial segments, is mediated by increased BP or is BP-independent.

METHODS

Three hundred and twenty-two Italian healthy adolescents (mean age 16.9±1.4 years, 12% with overweight) attending the "G. Donatelli" High School in Terni, Italy, underwent measurement of arterial stiffness by arterial tonometry (aortic stiffness) and semiautomatical detection of pressure-volume ratio of the common carotid (carotid stiffness). The mediator effect of BP was tested for each anthropometric or biochemical measure of fat excess related to arterial stiffness.

RESULTS

Both carotid and aortic stiffness showed positive correlations with body mass index, waist, hip, and neck circumferences (NC). Only carotid stiffness, but not aortic stiffness, was associated with serum markers of fat accumulation and metabolic impairment such as insulin, homeostatic model of insulin resistance (HOMA-IR), serum gamma-glutamyl transferase (sGGT) and uric acid. The association with NC was stronger for carotid than for aortic stiffness (Fisher z -to- R 2.07, P  = 0.04), and independent from BP.

CONCLUSIONS

In healthy adolescents, fat accumulation is associated with arterial stiffness. The degree of this association differs by arterial segments, since carotid stiffness is more strongly associated to adipose tissue excess than aortic stiffness and shows a BP-independent association with NC whereas aortic stiffness does not.

Brachial Blood Pressure Invasively and Non-Invasively Obtained Using Oscillometry and Applanation Tonometry: Impact of Mean Blood Pressure Equations and Calibration Schemes on Agreement Levels

The use of oscillometric methods to determine brachial blood pressure (bBP) can lead to a systematic underestimation of the invasively measured systolic (bSBP) and pulse (bPP) pressure levels, together with a significant overestimation of diastolic pressure (bDBP). Similarly, the agreement between brachial mean blood pressure (bMBP), invasively and non-invasively measured, can be affected by inaccurate estimations/assumptions. Despite several methodologies that can be applied to estimate bMBP non-invasively, there is no consensus on which approach leads to the most accurate estimation. Aims: to evaluate the association and agreement between: (1) non-invasive (oscillometry) and invasive bBP; (2) invasive bMBP, and bMBP (i) measured by oscillometry and (ii) calculated using six different equations; and (3) bSBP and bPP invasively and non-invasively obtained by applanation tonometry and employing different calibration methods. To this end, invasive aortic blood pressure and bBP (catheterization), and non-invasive bBP (oscillometry [Mobil-O-Graph] and brachial artery applanation tonometry [SphygmoCor]) were simultaneously obtained (34 subjects, 193 records). bMBP was calculated using different approaches. Results: (i) the agreement between invasive bBP and their respective non-invasive measurements (oscillometry) showed dependence on bBP levels (proportional error); (ii) among the different approaches used to obtain bMBP, the equation that includes a form factor equal to 33% (bMBP = bDBP + bPP/3) showed the best association with the invasive bMBP; (iii) the best approach to estimate invasive bSBP and bPP from tonometry recordings is based on the calibration scheme that employs oscillometric bMBP. On the contrary, the worst association between invasive and applanation tonometry-derived bBP levels was observed when the brachial pulse waveform was calibrated to bMBP quantified as bMBP = bDBP + bPP/3. Our study strongly emphasizes the need for methodological transparency and consensus for non-invasive bMBP assessment.

The Role of Cumulative Mean Arterial Pressure Levels in First Stroke Events Among Adults with Hypertension: A 10-Year Prospective Cohort Study

Background

Mean arterial pressure (MAP) has been proved to be an independent risk factor for stroke. In this study, we explored whether cumulative exposure of MAP in patients with hypertension is more associated with the occurrence of stroke.

Methods

In this prospective follow-up cohort study of hypertension from June 2010 to May 2020, 9136 participants without previous stroke at recruitment were included, of whom 492 (5.4%) had a first incident stroke during the study period (418 ischemic strokes and 74 hemorrhagic strokes). The study exposure factor was cumulative MAP, and was quartered from low to high (Q1, Q2, Q3, Q4). We analyzed the risk of first stroke using multivariable adjusted Cox regression models and used stratified analysis to further explore the risk of stroke in hypertensive patients with different characteristics.

Results

Increased cumulative MAP in patients with hypertension were associated with risk for ischemic stroke (HR, Q2, 1.23 [95% CI, 0.91–1.67]; Q3, 1.35 [95% CI, 1.01–1.82]; Q4, 1.55 [95% CI, 1.15–2.10]; P=0.035). Furthermore, this trend persisted after stratified analysis in men (HR, Q3, 1.76[1.10–2.82]; Q4, 2.05[1.28–3.28]), aged 60 or above (HR, Q4, 1.63[1.13–2.35]) and higher body mass index (BMI) populations (HR, Q3, 1.48[1.02–2.14]; Q4, 1.59[1.09–2.32]). In contrast, cumulative MAP was not significantly associated with stroke in women, age under 60, and non-obese individuals.

Conclusion

Increased cumulative MAP is an independent risk factor of ischemic stroke in patients with hypertension. Special attention should also be paid to men, aged 60 or older, or those with a higher BMI.

Arterial Stiffness Determinants for Primary Cardiovascular Prevention among Healthy Participants

Background: Arterial stiffness (AS), measured by arterial stiffness index (ASI), can be considered as a major denominator in cardiovascular (CV) diseases. Thus, it remains essential to highlight the risk factors influencing its increase among healthy participants. Methods: According to European consensus, AS is defined as ASI > 10 m/s. The purpose of this study was to investigate the determinants of the arterial stiffness (ASI > 10 m/s) among UK Biobank normotensive and healthy participants without comorbidities and previous CV diseases. Thus, a cross-sectional study was conducted on 22,452 healthy participants. Results: Participants were divided into two groups, i.e., ASI > 10 m/s (n = 5782, 25.8%) and ASI < 10 m/s (n = 16,670, 74.2%). All the significant univariate covariables were included in the multivariate analysis. The remaining independent factors associated with AS were age (OR = 1.063, threshold = 53.0 years, p < 0.001), BMI (OR = 1.0450, threshold = 24.9 kg/m2, p < 0.001), cystatin c (OR = 1.384, threshold = 0.85 mg/L, p = 0.011), phosphate (OR = 2.225, threshold = 1.21 mmol/L, p < 0.001), triglycerides (OR = 1.281, threshold = 1.09 mmol/L, p < 0.001), mean BP (OR = 1.028, threshold = 91.2 mmHg, p < 0.001), HR (OR = 1.007, threshold = 55 bpm, p < 0.001), Alkaline phosphate (OR = 1.002, threshold = 67.9 U/L, p = 0.004), albumin (OR = 0.973, threshold = 46.0 g/L, p < 0.001), gender (male, OR = 1.657, p < 0.001) and tobacco use (current, OR = 1.871, p < 0.001). Conclusion: AS is associated with multiple parameters which should be investigated in future prospective studies. Determining the markers of increased ASI among healthy participants participates in the management of future CV risk for preventive strategies.

Exposure to bedroom light pollution and cardiometabolic risk: A cohort study from Chinese young adults

Indoor light environment has altered dramatically and exposure to light at night (LAN) potential leads to the progression of cardiometabolic conditions. However, few studies have investigated the effect of bedroom LAN exposure on cardiometabolic risk. To estimate the associations between multi-period bedroom LAN exposure with cardiometabolic risk among Chinese young adults. We objectively measured multi-period bedroom LAN intensity using portable illuminance meter in an ongoing prospective cohort (n = 484). At one-year follow-up, 230 young adults provided fasting blood samples for quantification of cardiometabolic parameters. Cardiometabolic (CM)-risk score was derived as the sum of standardized sex-specific z-scores for waist circumference (WC), mean arterial pressure (MAP), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG) and homeostasis model assessment for insulin resistance (HOMA-IR), with HDL-C multiplied by - 1. Multivariate and univariable linear regression models were used to examine associations of multi-period bedroom LAN exposure with cardiometabolic risk. Exposure to higher bedroom LAN intensity is associated with 1.47-unit increase in CM-risk score (95% CI: 0.69-2.25; P < 0.001). Besides, post-bedtime light exposure was associated with elevated fasting insulin (PBL-1h: β = 0.06, 95% CI: 0.01-0.10; PBL-4h: β = 0.33, 95% CI: 0.19-0.47) and HOMA-IR (PBL-1h: β = 0.013, 95% CI: 0-0.03; PBL-4h: β = 0.07, 95% CI: 0.04-0.11) while pre-awake light exposure was associated with elevated total cholesterol (PAL-1h: β = 0.03, 95% CI: 0.02-0.04; PAL-2h: β = 0.02, 95% CI: 0.01-0.03), triglyceride (PAL-1h: β = 0.015, 95% CI: 0.01-0.02; PAL-2h: β = 0.01, 95% CI: 0-0.02) and low-density lipoprotein cholesterol (PAL-1h: β = 0.02, 95% CI: 0.01-0.03; PAL-2h: β = 0.02, 95% CI: 0.01-0.03). Among young adults, bedroom LAN exposure was significantly associated with higher cardiometabolic risk. Furthermore, different periods of bedroom light exposure have time-dependent effect on cardiometabolic risk. Further research is needed to confirm our findings and to elucidate potential mechanisms.

Hypercapnia-induced vasodilation in the cerebral circulation is reduced in older adults with sleep-disordered breathing

The prevalence of sleep-disordered breathing (SDB) is higher in older adults compared with younger individuals. The increased propensity for ventilatory control instability in older adults may contribute to the increased prevalence of central apneas. Reductions in the cerebral vascular response to CO₂ may exacerbate ventilatory overshoots and undershoots during sleep. Thus, we hypothesized that hypercapnia-induced cerebral vasodilation (HCVD) will be reduced in older compared with younger adults. In 11 older and 10 younger adults with SDB, blood flow velocity in the middle cerebral artery (MCAV) was measured using Doppler transcranial ultrasonography during multiple steady-state hyperoxic hypercapnic breathing trials while awake, interspersed with room air breathing. Changes in ventilation, MCAV, and mean arterial pressure (MAP) via finger plethysmography during the trials were compared with baseline eupneic values. For each hyperoxic hypercapnic trial, the change (Δ) in MCAV for a corresponding change in end-tidal CO₂ and the HCVD or the change in cerebral vascular conductance (MCAV divided by MAP) for a corresponding change in end-tidal CO₂ was determined. The hypercapnic ventilatory response was similar between the age groups, as was ΔMCAV/Δ[Formula: see text]. However, compared with young, older adults had a significantly smaller HCVD (1.3 ± 0.7 vs. 2.1 ± 0.6 units/mmHg, P = 0.004). Multivariable analyses demonstrated that age and nadir oxygen saturation during nocturnal polysomnography were significant predictors of HCVD. Thus, our data indicate that older age and SDB-related hypoxia are associated with diminished HCVD. We hypothesize that this impairment in vascular function may contribute to breathing instability during sleep in these individuals.NEW & NOTEWORTHY This study demonstrates, for the first time, in individuals with sleep-disordered breathing (SDB) that aging is associated with decreased hypercapnia-induced cerebral vasodilation (HCVD). In addition to advanced age, the magnitude of nocturnal oxygen desaturation due to SDB is an equal independent predictor of HCVD.

New Method to Estimate Central Systolic Blood Pressure From Peripheral Pressure: A Proof of Concept and Validation Study

Objective: The non-invasive estimation of central systolic blood pressure (cSBP) is increasingly performed using new devices based on various pulse acquisition techniques and mathematical analyses. These devices are most often calibrated assuming that mean (MBP) and diastolic (DBP) BP are essentially unchanged when pressure wave travels from aorta to peripheral artery, an assumption which is evidence-based. We tested a new empirical formula for the direct central blood pressure estimation of cSBP using MBP and DBP only (DCBP = MBP²/DBP).

Methods and Results: First, we performed a post-hoc analysis of our prospective invasive high-fidelity aortic pressure database (n = 139, age 49 ± 12 years, 78% men). The cSBP was 146.0 ± 31.1 mmHg. The error between aortic DCBP and cSBP was −0.9 ± 7.4 mmHg, and there was no bias across the cSBP range (82.5–204.0 mmHg). Second, we analyzed 64 patients from two studies of the literature in whom invasive high-fidelity pressures were simultaneously obtained in the aorta and brachial artery. The weighed mean error between brachial DCBP and cSBP was 1.1 mmHg. Finally, 30 intensive care unit patients equipped with fluid-filled catheter in the radial artery were prospectively studied. The cSBP (115.7 ± 18.2 mmHg) was estimated by carotid tonometry. The error between radial DCBP and cSBP was −0.4 ± 5.8 mmHg, and there was no bias across the range.

Conclusion: Our study shows that cSBP could be reliably estimated from MBP and DBP only, provided BP measurement errors are minimized. DCBP may have implications for assessing cardiovascular risk associated with cSBP on large BP databases, a point that deserves further studies.

Comparison Between Invasive and Noninvasive Methods to Estimate Subendocardial Oxygen Supply and Demand Imbalance

Background

Estimation of the balance between subendocardial oxygen supply and demand could be a useful parameter to assess the risk of myocardial ischemia. Evaluation of the subendocardial viability ratio (SEVR, also known as Buckberg index) by invasive recording of left ventricular and aortic pressure curves represents a valid method to estimate the degree of myocardial perfusion relative to left ventricular workload. However, routine clinical use of this parameter requires its noninvasive estimation and the demonstration of its reliability.

Methods and Results

Arterial applanation tonometry allows a noninvasive estimation of SEVR as the ratio of the areas directly beneath the central aortic pressure curves obtained during diastole (myocardial oxygen supply) and during systole (myocardial oxygen demand). However, this “traditional” method does not account for the intra‐ventricular diastolic pressure and proper allocation to systole and diastole of left ventricular isometric contraction and relaxation, respectively, resulting in an overestimation of the SEVR values. These issues are considered in the novel method for SEVR assessment tested in this study. SEVR values estimated with carotid tonometry by "traditional” and "new” method were compared with those evaluated invasively by cardiac catheterization. The “traditional” method provided significantly higher SEVR values than the reference invasive SEVR: average of differences±SD= 44±11% (limits of agreement: 23% – 65%). The noninvasive “new” method showed a much better agreement with the invasive determination of SEVR: average of differences±SD= 0±8% (limits of agreement: ‐15% to 16%).

Conclusions

Carotid applanation tonometry provides valid noninvasive SEVR values only when all the main factors determining myocardial supply and demand flow are considered.

Transfer-function-free technique for the noninvasive determination of the human arterial pressure waveform

The estimation of central aortic blood pressure is a cardinal measurement, carrying effective physiological, and prognostic data beyond routine peripheral blood pressure. Transfer function-based devices effectively estimate aortic systolic and diastolic blood pressure from peripheral pressure waveforms, but the reconstructed pressure waveform seems to preserve features of the peripheral waveform. We sought to develop a new method for converting the local diameter distension waveform into a pressure waveform, through an exponential function whose parameters depend on the local wave speed. The proposed method was then tested at the common carotid artery. Diameter and blood velocity waveforms were acquired via ultrasound at the right common carotid artery while simultaneously recording pressure at the left common carotid artery via tonometer in 203 people (122 men, 50 ± 18 years). The wave speed was noninvasively estimated via the lnDU-loop method and then used to define the exponential function to convert the diameter into pressure. Noninvasive systolic and mean pressures estimated by the new technique were 3.8 ± 21.8 (p = 0.015) and 2.3 ± 9.6 mmHg (p = 0.011) higher than those obtained using tonometery. However, differences were much reduced and not significant in people >35 years (0.6 ± 18.7 and 0.8 ± 8.3 mmHg, respectively). This proof of concept study demonstrated that local wave speed, estimated from noninvasive local measurement of diameter and flow velocity, can be used to determine an exponential function that describes the relationship between local pressure and diameter. This pressure-diameter function can then be used for the noninvasive estimation of local arterial pressure.

Association between Ideal Cardiovascular Health and aortic stiffness in Italian adolescents. The MACISTE study

BACKGROUND AND AIMS

Ideal Cardiovascular Health (ICH), defined as optimal levels of cardiovascular (CV) health factors and behaviors, has been reported to be very low in adults and children, with consequent several negative health outcomes and higher CV risk. The present study investigated the burden of ICH among Italian adolescents and its association with carotid-femoral pulse wave velocity (cf-PWV).

METHODS AND RESULTS

387 healthy adolescents (mean age 17.1 ± 1.4 years) attending the "G. Donatelli" High School in Terni, Italy, were evaluated. ICH was assessed through clinical evaluation, laboratory measures and interviewer-administered questionnaires. Cf-PWV was measured by arterial tonometry (SphygmoCor). For each ICH metric, a score of 2 was assigned for ideal levels, 1 for intermediate, and 0 for poor. All subjects showed at least one ICH metric, whereas none showed all ICH 7 metrics. The average number of ICH metrics was 4.3 ± 1.1. The highest rates were observed for fasting blood glucose (98%), whereas an ideal healthy diet was achieved only by 8% of subjects. The Cf-PWV was inversely and linearly associated with the sum of ICH metrics (p = 0.03) and the ICH score (p < 0.01). At the multivariate analysis, the association between ICH score and cf-PWV remained significant after adjustment for age, sex, heart rate, mean arterial pressure and other confounders (p = 0.04).

CONCLUSION

ICH is relatively uncommon among Italian adolescents and inversely related to cf-PWV. Our results showed a detrimental association between CV unhealthy factors and behaviors with increased aortic stiffness, which starts developing at an early stage of the lifespan.

Long-Term Visit-to-Visit Mean Arterial Pressure Variability and the Risk of Heart Failure and All-Cause Mortality

Background: Systolic or diastolic blood pressure (BP) variability is associated with an increased risk of cardiovascular events. We assessed whether BP variability measured by mean arterial pressure (MAP) was associated with increased risk of heart failure (HF) and death in individuals with or without hypertension. Methods: We evaluated 9,305 Atherosclerosis Risk in Communities (ARIC) study participants with or without hypertension and calculated BP variability based on MAP values from visit 1 to 4 [expressed as standard deviation (SD), average real variability (ARV), coefficient of variation (CV), and variability independent of the mean (VIM)]. Multivariate-adjusted Cox regression model and restricted cubic spline curve were used to evaluate the associations of MAP variability with all-cause mortality and HF. Results: During a median follow-up of 16.8 years, 1,511 had an HF event and 2,903 died. Individuals in the highest quartile of VIM were both associated with a 21% higher risk of all-cause mortality [hazard ratio (HR), 1.21; 95% CI, 1.09-1.35] and HF (HR, 1.21; 95% CI, 1.04-1.39) compared with the lowest quartile of VIM. Cubic spline curves reveal that the risk of deaths and HF increased with MAP variability when it reached a higher level. Results were similar in individuals with normotension (all-cause mortality: HR, 1.30; 95% CI, 1.09-1.55; HF, HR, 1.49; 95% CI, 1.12-1.98). Conclusions: In individuals with or without hypertension, greater visit-to-visit MAP variability was associated with a higher risk of all-cause mortality and HF, indicating that the BP variability assessed by MAP might be a potential risk factor for HF and death.

Pulse Wave Calibration and Implications for Blood Pressure Measurement: Systematic Review and Meta-Analysis

[Figure: see text].