Blood Pressure Distribution Research Articles

Impact of Vietnam-era G.I. Bill eligibility on later-life blood pressure distribution: evidence from the Vietnam draft lottery natural experiment.

We quantified the impact of Vietnam-era G.I Bill eligibility, which subsidized college education for eligible Veterans, on the later-life blood pressure distribution by exploiting the Vietnam draft lottery natural experiment. We restricted Health and Retirement Study data (2006-2018) to men born between 1947-1953 (N=1,970). We estimated intention-to-treat effects at the mean and 1st-99th quantiles of blood pressure using linear and quantile regressions. Our outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP), hypertension, and self-reported stroke. We proxied G.I. Bill eligibility using lottery-defined draft eligibility. We also conducted analyses stratified by childhood socioeconomic status (cSES) defined based on a previously validated measure. Draft eligibility reduced mean blood pressure outcomes (e.g., effect on SBP: -1.33 [95% confidence interval (CI) -2.85, 0.19]). Draft eligibility also had larger protective effects at higher quantiles of the SBP and DBP distributions relative to lower quantiles (effects on SBP at the 10th and 90th quantiles: -0.33mmHg [95% CI -2.35,1.68]; -3.00mmHg [95% CI -5.68,-0.32]). Draft eligibility had protective effects on blood pressure among low and medium cSES men but opposite effects among high cSES men. G.I. Bill eligibility reshaped the blood pressure distribution to one of lower morbidity risk, particularly among low and medium cSES men.

Tirzepatide and blood pressure reduction: stratified analyses of the SURMOUNT-1 randomised controlled trial

BackgroundTreating obesity may be a pathway to prevent and control hypertension. In the SURMOUNT-1 trial in people with obesity or overweight with weight-related complications, 72-week tirzepatide treatment led to clinically...

Validation of the JAMR upper-arm pressure monitor B23 according to the AAMI/ESH/ISO Universal Standard (ISO 81060- 2:2018/AMD 1:2020).

The aim of this study was to evaluate the accuracy of the JAMR upper-arm blood pressure monitor B23 in the general population according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). The study recruited participants who met the criteria of the AAMI/ESH/ISO Universal Standard in terms of their number, sex, age, limb size, and blood pressure (BP) distribution. The study involved measuring BP, including both SBP and DBP, using both the test device and a standard mercury sphygmomanometer in sequential measurements. Of 90 participants, 85 qualified participants were analyzed. A total of 255 sets of comparison data (three sets for each subject) were obtained and analyzed. For the validation criterion 1, the mean ± SD of the differences between the JAMR B23 and mercury sphygmomanometer BP readings was -0.24 ± 6.52/-2.67 ± 5.6 mmHg (SBP/DBP). For criterion 2, the SD of the averaged BP (SBP/DBP) differences between the JAMR B23 and reference BP (SBP/DBP) per participant was 5.61/5.13 mmHg (the requirement was ≤6.95/6.43 mmHg by calculation). The JAMR B23 passed all the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020) and can be recommended for clinical and self/home use in the general population.

Validation of the DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor in the general population according to the ISO 81060-2:2018/AMD 1:2020 protocol.

The aim of this study was to evaluate the accuracy of the DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor in the general population according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). The test monitor was used to measure SBP and DBP and pulse rate in the wrists using the oscillometric method. According to this protocol using the same-arm sequential blood pressure measurement method, subjects were recruited to fulfill the age, sex, blood pressure, and cuff distribution criteria of the Universal Standard. A single cuff for wrist sizes of 13.5-21.5 cm was used. A total of 85 subjects were included in this study. According to Criterion 1, the mean difference in SBP between the test device and the reference device was 0.89 mmHg, with a SD of 7.76 mmHg. The mean difference of DBP was -1.44 mmHg, with a SD of 6.23 mmHg. The mean difference between SBP and DBP was less than 5.0 mmHg, and the SD was less than 8.0 mmHg, which met the requirements. According to Criterion 2, the SD of the mean differences of SBP between the test device and the reference device per subject was 5.65 mmHg, which was less than 6.88 mmHg and met the requirements. The SD of the mean differences of DBP between the test device and the reference device per subject was 5.61 mmHg, which was less than 6.78 mmHg and met the requirements. The DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor met the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). It can be recommended for home and clinical use.

Static and dynamic analysis of cerebral blood flow in fifty-six large arterial vessel networks

Objective. The cerebral vasculature is formed of an intricate network of blood vessels over many different length scales. Changes in their structure and connection are implicated in multiple cerebrovascular and neurological disorders. In this study, we present a novel approach to the quantitative analysis of the cerebral macrovasculature using computational and mathematical tools in a large dataset. Approach. We analysed a publicly available vessel dataset from a cohort of 56 (32/24F/M) healthy subjects. This dataset includes digital reconstructions of human brain macrovasculatures. We then propose a new mathematical model to compute blood flow dynamics and pressure distributions within these 56-representative cerebral macrovasculatures and quantify the results across this cohort. Main results. Statistical analysis showed that the steady state level of cerebrovascular resistance (CVR) gradually increases with age in both men and women. These age-related changes in CVR are in good agreement with previously reported values. All subjects were found to have only small phase angles (<6°) between blood pressure and blood flow at the cardiac frequency. Significance. These results showed that the dynamic component of blood flow adds very little phase shift at the cardiac frequency, which implies that the cerebral macrocirculation can be regarded as close to steady state in its behaviour, at least in healthy populations, irrespective of age or sex. This implies that the phase shift observed in measurements of blood flow in cerebral vessels is caused by behaviour further down the vascular bed. This behaviour is important for future statistical models of the dynamic maintenance of oxygen and nutrient supply to the brain.

Multifaceted simulation: Finite volume and finite element modeling of blood flow in multiple stenosed arteries

Cardiovascular illnesses are a primary global health concern because they are frequently brought on by arterial stenosis. The complicated hemodynamics of blood flow via elliptically shaped arteries with numerous stenotic lesions along their top and bottom walls are examined in this paper. Carreau fluid model is used with Navier–Stokes equations in this study. The complete comparative study is done by using the Finite Element and Finite Volume Methods. This study uses commercial software to examine blood flow velocity, pressure and temperature distributions under various physiological situations at Reynolds number 30. Our results illuminate the interaction between flow dynamics, stenosis characteristics, and arterial geometry. The novelty of the work is to investigate how stenosis size, shape, and location affect pressure gradients, and flow disturbances. These observations provide helpful direction for understanding disease progression, designing treatments, and possibly new stent designs. The future direction of this research may involve further exploration of the interplay between hemodynamics and arterial stenosis by incorporating advanced computational models. Additionally, studies focusing on in vivo validation and clinical applications could enhance the translational impact of the findings. Collaborations between researchers, clinicians, and engineers may pave the way for personalized treatment strategies and innovations in cardiovascular care based on a deeper understanding of the intricate dynamics within diseased arteries.

Fair non-contact blood pressure estimation using imaging photoplethysmography.

Hypertension is typically manifested as a latent symptom that requires detection through specialized equipment. This poses an inconvenience for individuals who need to undergo long-term blood pressure monitoring in their daily lives. Therefore, there is a need for a portable, non-contact method for estimating blood pressure. However, current non-contact blood pressure estimation methods often rely on relatively narrow datasets, lacking a broad range of blood pressure distributions. Additionally, their applicability is confined to controlled experimental environments. This study proposes a non-contact blood pressure estimation method suitable for various life scenarios, encompassing multiple age groups, diverse ethnicities, and individuals with different skin tones. The aim is to enhance the practicality and accuracy of existing non-contact blood pressure estimation methods. The research extracts the imaging photoplethysmogram (IPPG) signal from facial videos and processes the signal through four layers of filtering operations to obtain an IPPG signal reflecting pulse wave variations. A CNN+BiLSTM+GRU network structure is constructed to improve the accuracy of current non-contact blood pressure estimation methods. In comparison to existing approaches, the mean absolute error (MAE) for systolic blood pressure (SBP) and diastolic blood pressure (DBP) is reduced by 13.6% and 16.4%, respectively.

Hemodynamic factors of spontaneous vertebral artery dissecting aneurysms assessed with numerical and deep learning algorithms: Role of blood pressure and asymmetry

Background and ObjectivesThe pathophysiology of spontaneous vertebral artery dissecting aneurysms (SVADA) is poorly understood. Our goal is to investigate the hemodynamic factors contributing to their formation using computational fluid dynamics (CFD) and deep learning algorithms. MethodsWe have developed software that can use patient imagery as input to recreate the vertebrobasilar arterial system, both with and without SVADA, which we used in a series of three patients. To obtain the kinematic blood flow data before and after the aneurysm forms, we utilized numerical methods to solve the complex Navier-Stokes partial differential equations. This was accomplished through the application of a finite volume solver (OpenFoam/Helyx OS). Additionally, we trained a neural ordinary differential equation (NODE) to learn and replicate the dynamical streamlines obtained from the computational fluid dynamics (CFD) simulations. ResultsIn all three cases, we observed that the equilibrium of blood pressure distributions across the VAs, at a specific vertical level, accurately predicted the future SVADA location. In the two cases where there was a dominant VA, the dissection occurred on the dominant artery where blood pressure was lower compared to the contralateral side. The SVADA sac was characterized by reduced wall shear stress (WSS) and decreased velocity magnitude related to increased turbulence. The presence of a high WSS gradient at the boundary of the SVADA may explain its extension. Streamlines generated by CFD were learned with a neural ordinary differential equation (NODE) capable of capturing the system’s dynamics to output meaningful predictions of the flow vector field upon aneurysm formation. ConclusionIn our series, asymmetry in the vertebrobasilar blood pressure distributions at and proximal to the site of the future SVADA accurately predicted its location in all patients. Deep learning algorithms can be trained to model blood flow patterns within biological systems, offering an alternative to the computationally intensive CFD. This technology has the potential to find practical applications in clinical settings.

Noninvasive assessment of pressure distribution and fractional flow in middle cerebral artery using microbubbles and plane wave in vitro

Fractional flow has been proposed for quantifying the degree of functional stenosis in cerebral arteries. Herein, subharmonic aided pressure estimation (SHAPE) combined with plane wave (PW) transmission was employed to noninvasively estimate the pressure distribution and fractional flow in the middle cerebral artery (MCA) in vitro. Consequently, the effects of incident sound pressure (peak negative pressures of 86–653 kPa), pulse repetition frequency (PRF), number of pulses, and blood flow rate on the subharmonic pressure relationship were investigated. The radio frequency data were stored and beamformed offline, and the subharmonic amplitude over a 0.4 MHz bandwidth was extracted using a 12-cycle PW at 4 MHz. The optimal incident sound pressure was 217 kPa without skull (sensitivity = 0.09 dB/mmHg; r2 = 0.997) and 410 kPa with skull (median sensitivity = 0.06 dB/mmHg; median r2 = 0.981). The optimal PRF was 500 Hz, as this value affords the highest sensitivity (0.09 dB/mmHg; r2 = 0.976) and temporal resolution. In addition, the blood flow rate exhibited a lesser effect on the subharmonic pressure relationship in our experimental setup. Using the optimized parameters, the blood pressure distribution and fractional flow (FFs) were measured. As such, the FFs value was in high agreement with the value measured using the pressure sensor (FFm). The mean ± standard deviations of the FF difference (FFm − FFs) were 0.03 ± 0.06 without skull and 0.01 ± 0.05 with skull.

Software-driven chronic disease management: Algorithm design and implementation in a community-based blood pressure control pilot

Background: Optimal guideline-directed medical therapy is rarely attained in practice, resulting in inadequate control of diseases such as hypertension, with poorer results in under-resourced communities. Technology, including artificial intelligence-driven decision support and software-driven workflow transformation, can potentially improve disease outcomes at a reduced cost, although it must be integrated with a holistic approach. Methods: We describe the design of a software platform that enables rapid iterative remote management of &gt;20 conditions across cardiac-kidney-metabolic disease. The platform distributes work across a care team of providers and care navigators, automates decision-making, ordering, and documentation, supports rapid incorporation of new evidence, and launches pragmatic trials. We describe software used in a 500-person community-based blood pressure control implemented as a single-arm quality improvement program. The primary endpoint was the proportion of patients meeting the Healthcare Effectiveness Data and Information Set quality measure blood pressure goal (&lt;140/90) at 12 weeks. Results: A total of 1609 patients were screened, 945 (59%) were found to have uncontrolled hypertension, and 512 patients consented to join the program. The average age was 61 ± 11 years; 59% were female, and 99% self-identified as Black. Blood pressure distribution was: 10% Stage 1 (SBP 130–139 mmHg or DBP 80–89 mmHg), 69% Stage 2 (SBP 140–179 mmHg or DBP 90–119 mmHg), and 21% Stage 3 (SBP &gt;180 mmHg or DBP &gt;120 mmHg). Two hundred four patients (39%) proceeded to a provider encounter, and 160 of these (78%) completed the program. The Healthcare Effectiveness Data and Information Set blood pressure goal was achieved in &lt;12 weeks of enrollment for 141 participants (69% of those enrolled, 88% of those who completed the program). Conclusion: Software-driven remote blood pressure is feasible, although strategies to improve patient enrollment will be needed to achieve maximum impact. Future work will be required to compare outcomes to usual care and evaluate concurrent management of multiple cardiac-kidney-metabolic conditions.

Fractional-Order Modeling of Arterial Compliance in Vascular Aging: A Computational Biomechanical Approach for Investigating Cardiovascular Dynamics.

Goal: The goal of this study is to investigate the application of fractional-order calculus in modeling arterial compliance in human vascular aging. Methods: A novel fractional-order modified arterial Windkessel model that incorporates a fractional-order capacitor (FOC) element is proposed to capture the complex and frequency-dependent properties of arterial compliance. The model's performance is evaluated by verifying it using data collected from three different human subjects, with a specific focus on aortic pressure and flow rates. Results: The results show that the FOC model accurately captures the dynamics of arterial compliance, providing a flexible means to estimate central blood pressure distribution and arterial stiffness. Conclusions: This study demonstrates the potential of fractional-order calculus in advancing the modeling and characterization of arterial compliance in human vascular aging. The proposed FOC model can improve our understanding of the physiological changes in arterial compliance associated with aging and help to identify potential interventions for age-related cardiovascular diseases.

A review on the role of novel adipokine Isthmin-1 and Subfatin in human type 2 diabetes mellitus

Adipokines are essential for maintaining cardiovascular and metabolic balance. The term "adipokines" refers to peptides in the pancreas, brain, vascular system, liver, immune system and muscle. adipokines regulate numbers of factors, such as energy expenditure, hunger, satiety, insulin sensitivity, and blood pressure, insulin secretion, adipogenesis and fat distribution, and that might make them play a role in future pharmacological treatment strategies for obesity and metabolic diseases. Isthmin-1 (Ism-1) is a recently discovered insulin-like adipokine that suppresses hepatic lipids. According to recent research, Ism-1 can enhance lipid metabolism and treat metabolic disorders linked to type 2 diabetic mellitus (T2DM). The primary source of the protein subfatin (SUB) is white adipose tissue. Subfatin (SUB) is expressed in these following tissues: adipose tissue, brain tissue, thymus gland, liver, activated human monocytes, spleen, omental adipose tissue, muscle, salivary glands and heart tissues. The SUB lowers insulin resistance to control glucose metabolism. Isthmian-1 is a novel biomarker for early management and diagnosis of T2DM and has a beneficial effect in glucose homeostasis and might be therapeutic for diabetes. Subfatin also plays a role in glucose metabolism and insulin sensitivity, so it has significant effect in pathogenesis and complication of diabetes.

Modeling of blood flow in cerebral arterial circulation and its dynamic impact on electrical conductivity in a realistic multi-compartment head model

Background and ObjectiveThis study aims to assess the dynamic impact of non-Newtonian cerebral arterial circulation on electrical conductivity within a realistic multi-compartment head model. Evaluating this research question is crucial and challenging due to its relevance to electrophysiological modalities like transcranial electrical stimulation (tES), electro-/magnetoencephalography (EEG/MEG), and electrical impedance tomography (EIT). In these modalities, accurate forward modeling depends on the electrical conductivity, which is affected by complex tortuous vessel networks, limited data acquisition in Magnetic Resonance Imaging (MRI), and non-linear blood flow phenomena, including shear rate and viscosity in non-Newtonian fluid. MethodsTo obtain an approximation for the blood concentration, we first use Navier–Stokes equations (NSEs) to solve for the pressure and velocity of the blood in the major vessels. Then Fick's law is used to solve for the blood concentration in the tissues. Finally, Archie's law is used to estimate the electrical conductivity distribution based on the blood concentration. ResultsThe results, obtained with an open 7 Tesla MRI dataset, suggest that a dynamic model of cerebral blood flow (CBF) for both arterial and microcirculation can be established; we find blood pressure and electrical conductivity distributions given a numerically simulated pulse sequence and approximate the blood concentration and electrical conductivity inside the brain based on those. ConclusionsOur model provides an approximation of the dynamical blood flow and the corresponding electrical conductivity distribution in the different parts of the brain. The advantage of our approach is that it is applicable with limited a priori information about the blood flow and with an arbitrary head model distinguishing the arteries.

Association of blood pressure with neurologic outcome at hospital discharge after pediatric cardiac arrest resuscitation

BackgroundPoor outcomes are associated with post cardiac arrest blood pressures <5th percentile for age. We aimed to study the relationship of mean arterial pressure (MAP) with favorable neurologic outcome following cardiac arrest and return of spontaneous circulation (ROSC). MethodsThis retrospective, multi-center, observational study analyzed data from the Pediatric Resuscitation Quality Collaborative (pediRES-Q). Children (<18 years) who achieved ROSC following index in-hospital or out-of-hospital cardiac arrest and survived ≥6 hours were included. Lowest documented MAP within the first 6 hours of ROSC was percentile adjusted for age and categorized into six groups – Group I: <5th, II: 5–24th, III: 25–49th, IV: 50–74th, V: 75–94th; and VI: 95–100th percentile. Primary outcome was favorable neurologic status at hospital discharge, defined as PCPC score 1, 2, or no change from pre-arrest baseline. Multivariable logistic regression was performed to analyze the association of MAP group with favorable outcome, controlling for illness category (surgical-cardiac), initial rhythm (shockable), arrest time (weekend or overnight), age, CPR duration, and clustering by site. Results787 patients were included: median [Q1,Q3] age 17.9 [4.8,90.6] months; male 58%; OHCA 21%; shockable rhythm 13%; CPR duration 7 [3,16] min; favorable neurologic outcome 54%. Median lowest documented MAP percentile for the favorable outcome group was 13 [3,43] versus 8 [1,37] for the unfavorable group. The distribution of blood pressures by MAP group was I: 37%, II: 28%, III: 13%, IV: 11%, V: 7%, and VI: 4%. Compared with patients in Group I (<5%ile), Groups II, III, and IV had higher odds of favorable outcome (aOR, 1.84 [95% CI, 1.24, 2.73]; 2.20 [95% CI, 1.32, 3.68]; 1.90 [95% CI, 1.12, 3.25]). There was no association between Groups V or VI and favorable outcome (aOR, 1.44 [95% CI, 0.75, 2.80]; 1.11 [95% CI, 0.47, 2.59]). ConclusionIn the first 6-hours post-ROSC, a lowest documented MAP between the 5th−74th percentile for age was associated with favorable neurologic outcome compared to MAP <5th percentile for age.

Validation of the automated oscillometric upper-arm cuff home blood pressure monitor AVITA BPM82 in a general population according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard.

This study evaluated the accuracy of the automated oscillometric upper-arm cuff device AVITA BPM82 intended for home use in a general population according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard (ISO 81060-2:2018) and its Amendment 1.2020-01. Participants were recruited to fulfill the age, sex, blood pressure (BP), and limb distribution criteria of the AAMI/ESH/ISO Universal Standard and its Amendment 1.2020-01 in a general population using the same arm sequential BP measurement method. Two cuffs of the test device were used for arm circumference 22-33 (medium) and 33-42 cm (large). One-hundred-one individuals were recruited and 85 were analyzed [mean age 57.3 ± 15.1 (SD) years, 46 men, arm circumference 32 ± 5.1 cm, range 22.3-42 cm]. For validation Criterion 1, the mean difference ±SD between the test device and reference BP readings (N = 255) was 1.3 ± 6.5/3.6 ± 5.9 mmHg (systolic/diastolic; threshold ≤5 ± 8 mmHg). For Criterion 2, the SD of the averaged BP differences between the test device and reference BP per individual (N = 85) was 5.70/5.25 mmHg (systolic/diastolic; threshold ≤6.82/5.89 mmHg). The automated oscillometric home BP monitor AVITA BPM82 comfortably fulfilled all the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018) and its Amendment 1.2020-01 in a general population and can be recommended for clinical use.

Fluid–Structure Interaction Aortic Valve Surgery Simulation: A Review

The complicated interaction between a fluid flow and a deformable structure is referred to as fluid–structure interaction (FSI). FSI plays a crucial role in the functioning of the aortic valve. Blood exerts stresses on the leaflets as it passes through the opening or shutting valve, causing them to distort and vibrate. The pressure, velocity, and turbulence of the fluid flow have an impact on these deformations and vibrations. Designing artificial valves, diagnosing and predicting valve failure, and improving surgical and interventional treatments all require the understanding and modeling of FSI in aortic valve dynamics. The most popular techniques for simulating and analyzing FSI in aortic valves are computational fluid dynamics (CFD) and finite element analysis (FEA). By studying the relationship between fluid flow and valve deformations, researchers and doctors can gain knowledge about the functioning of valves and possible pathological diseases. Overall, FSI is a complicated phenomenon that has a great impact on how well the aortic valve works. Aortic valve diseases and disorders can be better identified, treated, and managed by comprehending and mimicking this relationship. This article provides a literature review that compiles valve reconstruction methods from 1952 to the present, as well as FSI modeling techniques that can help advance valve reconstruction. The Scopus, PubMed, and ScienceDirect databases were used in the literature search and were structured into several categories. By utilizing FSI modeling, surgeons, researchers, and engineers can predict the behavior of the aortic valve before, during, and after surgery. This predictive capability can contribute to improved surgical planning, as it provides valuable insights into hemodynamic parameters such as blood flow patterns, pressure distributions, and stress analysis. Additionally, FSI modeling can aid in the evaluation of different treatment options and surgical techniques, allowing for the assessment of potential complications and the optimization of surgical outcomes. It can also provide valuable information on the long-term durability and functionality of prosthetic valves. In summary, fluid–structure interaction modeling is an effective tool for predicting the outcomes of aortic valve surgery. It can provide valuable insights into hemodynamic parameters and aid in surgical planning, treatment evaluation, and the optimization of surgical outcomes.

The Pattern of Blood Pressure Distribution and Analysis of Influencing Factors of Pre (Hypertension) Among Young Adults: A Cross-Sectional Survey in Western India

Background: Raised blood pressure is one of the significant preventable causes of cardiovascular diseases. The Global Burden of Diseases report 2019 has identified high systolic blood pressure as the leading risk factor for attributable deaths accounting for about 1.4 million deaths in India. The study aimed to determine the prevalence of prehypertension and hypertension, along with their associated risk factors, among young adults. Methods: A cross-sectional study was conducted in urban science colleges in Gujarat. A multicomponent questionnaire comprised of demographic, dietary and lifestyle characteristics was administered to the participants (18-23 years). Data on weight, height and blood pressure were collected by trained field personnel. The categorical variables were tested by a chi-square test, while the t-test was used to compare quantitative variables. Results: Overall, 415 participants (65% female) were included in the study, with a mean age of 19.5 years. The prevalence of prehypertension and hypertension was 23.4% and 4.8%, respectively. The multivariate analysis showed that the male gender, not being underweight, and overweight was found to be associated with elevated blood pressure. Conclusions: There is a pressing need to identify cardiovascular risk factors at younger ages through regular screening, with more focus should be put on the adaptation of healthy lifestyles.

Simulation of coronary capillary transit time based on full vascular model of the heart

Capillary transit time (CTT) is a fundamental determinant of gas exchange between blood and tissues in the heart and other organs. Despite advances in experimental techniques, it remains difficult to measure coronary CTT in vivo. Here, we developed a novel computational framework that couples coronary microcirculation with cardiac mechanics in a closed-loop system that enables prediction of hemodynamics in the entire coronary network, including arteries, veins, and capillaries. We also developed a novel “particle-tracking” approach for computing CTT where “virtual tracers” are individually tracked as they traverse the capillary network. Model predictions compare well with blood pressure and flow rate distributions in the arterial network reported in previous studies. Model predictions of transit times in the capillaries (1.21 ± 1.5 s) and entire coronary network (11.8 ± 1.8 s) also agree with measurements. We show that, with increasing coronary artery stenosis (as quantified by fractional flow reserve, FFR), intravascular pressure and flow rate downstream are reduced but remain non-stationary even at 100 % stenosis because some flow (∼3 %) is redistributed from the non-occluded to the occluded territories. Importantly, the model predicts that occlusion of a large artery results in higher CTT. For moderate stenosis (FFR > 0.6), the increase in CTT (from 1.21 s without stenosis to 2.23 s at FFR=0.6) is caused by a decrease in capillary flow rate. In severe stenosis (FFR = 0.1), the increase in CTT to 14.2 s is due to both a decrease in flow rate and an increase in path length taken by “virtual tracers” in the capillary network.

Genetic Markers Regulating Blood Pressure in Extreme Discordant Sib Pairs.

Genome-wide scans performed in affected sib pairs have revealed small and often inconsistent clues to the loci responsible for the inherited components of hypertension. Since blood pressure is a quantitative trait regulated by many loci, two siblings at opposite extremes of the blood pressure distribution are more likely to have inherited different alleles at any given locus. Hence, we investigated an extreme discordant sib pair strategy to analyse markers from two previous loci of interest: (1) the Gordons syndrome locus that includes the WNK4 gene and (2) the ROMK locus identified in our first genome-wide scan. For this study, 24 sib pairs with strong family histories of essential hypertension were selected from the top and bottom 10% of the blood pressure distribution and genotyped for highly polymorphic microsatellite markers on chromosomes 11 and 17. The mean age of the population was 39.8 ± 7.8 years. A significant inverse correlation was found between the squared difference in pulse pressure and the number of alleles shared by IBD between the siblings for the DS11925 marker (r = -0.44, p = 0.031), systolic pressure and chromosome 17 markers (D17S250: r = -0.42, p = 0.040; D17S799 (r = -0.51, p = 0.011), and this relationship persisted after correcting for age and gender. Markers on chromosome 17 (D17S250, D17S928 and D17S1301) and 11 (D11S1999) also correlated with diastolic pressure. These results illustrate the successful use of discordant sib pair analysis to detect linkage within relatively small numbers of pedigrees with hypertension. Further analysis of this cohort may be valuable in complementing findings from the large genome wide scans in affected sib pairs.

Secular trends and age-specific distribution of blood pressure in Japanese adolescents aged 12-18 years in 2000-2019.

Adolescent blood pressure is a predictor of future risk for hypertension and cardiovascular diseases, and therefore its status needs to be accurately determined. However, limited evidence is available regarding the secular trends and distribution of adolescent blood pressure. In the present study, we assessed the secular trends and age-specific distributions of blood pressure in Japanese adolescents aged 12-18 years by using data drawn from 20 years of annual health checkups conducted between 2000 and 2019. Participants underwent health checkups every year for three years at the same school and the data were divided into four 5-year cycles: 2000-2004, 2005-2009, 2010-2014, and 2015-2019. From a total of 124,460 records (33,496 individuals) retrieved, 3000 records (3000 individuals) from each year-cycle were randomly selected to avoid duplicating data from the same individuals. In the study period, in males systolic blood pressure showed a decreasing trend over time, whereas in females diastolic blood pressure showed an increasing trend. Subgroup analyses by school category (junior/senior high school) and by obesity category showed similar blood pressure trends as in the overall analysis. Age-specific blood pressure values in Japanese adolescents increased with age in males but not in females. Thus, different patterns of change in blood pressure values over the past 20 years were observed between males and females. Age-specific blood pressure distributions are also presented. Together, these findings will be useful for understanding blood pressure trends among adolescents.