Graph Machine Learning for Improved Imputation of Missing Tropospheric Ozone Data.

Gaps in the measurement series of atmospheric pollutants can impede the reliable assessment of their impacts and trends. We propose a new method for missing data imputation of the air pollutant tropospheric ozone by using the graph machine learning algorithm "correct and smooth". This algorithm uses auxiliary data that characterize the measurement location and, in addition, ozone observations at neighboring sites to improve the imputations of simple statistical and machine learning models. We apply our method to data from 278 stations of the year 2011 of the German Environment Agency (Umweltbundesamt - UBA) monitoring network. The preliminary version of these data exhibits three gap patterns: shorter gaps in the range of hours, longer gaps of up to several months in length, and gaps occurring at multiple stations at once. For short gaps of up to 5 h, linear interpolation is most accurate. Longer gaps at single stations are most effectively imputed by a random forest in connection with the correct and smooth. For longer gaps at multiple stations, the correct and smooth algorithm improved the random forest despite a lack of data in the neighborhood of the missing values. We therefore suggest a hybrid of linear interpolation and graph machine learning for the imputation of tropospheric ozone time series.

Exploring the direct and indirect effects of cardiovascular disease risk factors on exercise blood pressure.

OBJECTIVE: Exaggerated exercise blood pressure (BP) is independently associated with cardiovascular disease (CVD) outcomes. However, it is unknown how individual CVD risk factors may interact with one another to influence exercise BP. The aim of this study was to quantify direct and indirect associations between CVD risk factors and exercise BP, to determine what CVD risk factor/s most-strongly relate to exercise BP. METHODS: In a cross-sectional design, 660 participants (44 ± 2.6 years, 54% male) from the population-based Childhood Determinants of Adult Health Study had BP measured during low-intensity fixed-workload cycling. CVD risk factors were measured, including body composition, clinic (rest) BP, blood biomarkers, and cardiorespiratory fitness. Associations between CVD risk factors and exercise BP were assessed using linear regression, with direct and indirect pathways of association assessed via structural equation model. RESULTS: Sex, waist-to-hip ratio, fitness, and clinic BP were independently associated with exercise systolic BP (SBP), and along with age, had direct associations with exercise SBP (p < 0.05 all). Most CVD risk factors were indirectly associated with exercise SBP via a relation with clinic BP (p < 0.05 all). Clinic BP, waist-to-hip ratio, and fitness were most-strongly associated (direct and indirect association) with exercise SBP (ß[95% CI]: 9.35 [8.04, 10.67], 4.91 [2.56, 7.26], and -2.88 [-4.25, -1.51] mm Hg/SD, respectively). CONCLUSION: Many CVD risk factors are associated with exercise BP, mostly with indirect effects via clinic BP. Clinic BP, body composition, and fitness were most-strongly associated with exercise BP. These results may elucidate how lifestyle modification could be a primary strategy to decrease exaggerated exercise BP-related CVD risk.

Cardiorespiratory Fitness, Workload, and the Blood Pressure Response to Exercise Testing.

We propose that for correct clinical interpretation of exaggerated exercise blood pressure (EEBP), both cardiorespiratory fitness and exercise workload must be considered. A key recommendation toward achieving the correct clinical interpretation of EEBP is that exercise BP should be measured during submaximal exercise with a fixed external workload.

Mapping Yearly Fine Resolution Global Surface Ozone through the Bayesian Maximum Entropy Data Fusion of Observations and Model Output for 1990-2017.

Estimates of ground-level ozone concentrations are necessary to determine the human health burden of ozone. To support the Global Burden of Disease Study, we produce yearly fine resolution global surface ozone estimates from 1990 to 2017 through a data fusion of observations and models. As ozone observations are sparse in many populated regions, we use a novel combination of the M3Fusion and Bayesian Maximum Entropy (BME) methods. With M3Fusion, we create a multimodel composite by bias-correcting and weighting nine global atmospheric chemistry models based on their ability to predict observations (8834 sites globally) in each region and year. BME is then used to integrate observations, such that estimates match observations at each monitoring site with the observational influence decreasing smoothly across space and time until the output matches the multimodel composite. After estimating at 0.5° resolution using BME, we add fine spatial detail from an additional model, yielding estimates at 0.1° resolution. Observed ozone is predicted more accurately (R2 = 0.81 at the test point, 0.63 at 0.1°, and 0.62 at 0.5°) than the multimodel mean (R2 = 0.28 at 0.5°). Global ozone exposure is estimated to be increasing, driven by highly populated regions of Asia and Africa, despite decreases in the United States and Russia.

General practitioner perceptions of assessment and reporting of absolute cardiovascular disease risk via pathology services: a qualitative study.

BACKGROUND: Guidelines for cardiovascular disease (CVD) prevention recommend assessment of absolute CVD risk to guide clinical management. Despite this, use among general practitioners (GPs) remains limited. OBJECTIVE: Pathology services may provide an appropriate setting to assess and report absolute CVD risk in patients attending for cholesterol measurement. This study aimed to explore GPs perceptions of such a service. METHODS: A focus group and semi-structured interviews were conducted with GPs (n = 18) in Tasmania, Australia, to identify perceptions of assessment and reporting of absolute CVD risk via pathology services. An example pathology report including absolute CVD risk was provided and discussed. Audio-recordings were transcribed and thematically coded by two researchers. RESULTS: Almost all GPs identified that absolute CVD risk assessed and reported via pathology services could address deficits in practice. First, by reducing the number of appointments required to collect risk factors. Second, by providing a systematic (rather than opportunistic) approach for assessment of absolute CVD risk. Third, by reducing misclassification of patient CVD risk caused by overreliance on clinical intuition. All GPs reported they would order absolute CVD risk when issuing a cholesterol referral if such a service was offered. GPs recommended improving the service by providing information on methods used to measure risk factors on the pathology report. CONCLUSIONS: Absolute CVD risk assessed and reported via pathology services may address challenges of screening CVD risk experienced by GPs in practice and encourage dedicated follow-up care for CVD prevention.

Cardiorespiratory fitness, fatness, and the acute blood pressure response to exercise in adolescence.

OBJECTIVE: Exaggerated exercise blood pressure (BP) is associated with cardiovascular risk factors in adolescence. Cardiorespiratory fitness and adiposity (fatness) are independent contributors to cardiovascular risk, but their interrelated associations with exercise BP are unknown. This study aimed to determine the relationships between fitness, fatness, and the acute BP response to exercise in a large birth cohort of adolescents. METHODS: 2292 adolescents from the Avon Longitudinal Study of Parents and Children (aged 17.8 ± 0.4 years, 38.5% male) completed a sub-maximal exercise step test that allowed fitness (VO2 max ) to be determined from workload and heart rate using a validated equation. Exercise BP was measured immediately on test cessation and fatness calculated as the ratio of total fat mass to total body mass measured by DXA. RESULTS: Post-exercise systolic BP decreased stepwise with tertile of fitness (146 (18); 142 (17); 141 (16) mmHg) but increased with tertile of fatness (138 (15); 142 (16); 149 (18) mmHg). In separate models, fitness and fatness were associated with post-exercise systolic BP adjusted for sex, age, height, smoking, and socioeconomic status (standardized ß: -1.80, 95%CI: -2.64, -0.95 mmHg/SD and 4.31, 95%CI: 3.49, 5.13 mmHg/SD). However, when fitness and fatness were included in the same model, only fatness remained associated with exercise BP (4.65, 95%CI: 3.69, 5.61 mmHg/SD). CONCLUSION: Both fitness and fatness are associated with the acute BP response to exercise in adolescence. The fitness-exercise BP association was not independent of fatness, implying the cardiovascular protective effects of cardiorespiratory fitness may only be realized with more favorable body composition.

Cuff Under Pressure for Greater Accuracy.

PURPOSE OF REVIEW: To present the evidence that describes what is being measured by upper-arm cuff blood pressure (BP) and the level of accuracy compared with invasive central aortic and brachial BP. Potential causes of inaccuracy and emerging methods are also discussed. RECENT FINDINGS: On average cuff systolic BP systematically underestimates invasive brachial systolic BP, although in a given individual it may substantially under- or over-estimate central aortic systolic BP. Such errors may affect individual health management outcomes and distort population level data on hypertension prevalence and control. Oscillometric cuff BP is particularly susceptible to inaccuracy in people with high arterial stiffness and with pathophysiological BP waveform shapes. Emerging cuff-less BP methods will be susceptible to inaccuracy if oscillometric cuff BP is used for calibration. The original purpose of cuff BP was to estimate central aortic BP. Recent evidence has shown substantial inaccuracy of oscillometric cuff BP exists for the measurement of invasive central aortic and brachial BP. Thus, development of more accurate BP methods, through better understanding of oscillometric and BP waveform morphology, is needed to improve health outcomes related to high BP.

Impact of U.S. Oil and Natural Gas Emission Increases on Surface Ozone Is Most Pronounced in the Central United States.

Observations of volatile organic compounds (VOCs) from a surface sampling network and simulation results from the EMAC (ECHAM5/MESSy for Atmospheric Chemistry) model were analyzed to assess the impact of increased emissions of VOCs and nitrogen oxides from U.S. oil and natural gas (O&NG) sources on air quality. In the first step, the VOC observations were used to optimize the magnitude and distribution of atmospheric ethane and higher-alkane VOC emissions in the model inventory for the base year 2009. Observation-based increases of the emissions of VOCs and NOx stemming from U.S. oil and natural gas (O&NG) sources during 2009-2014 were then added to the model, and a set of sensitivity runs was conducted for assessing the influence of the increased emissions on summer surface ozone levels. For the year 2014, the added O&NG emissions are predicted to affect surface ozone across a large geographical scale in the United States. These emissions are responsible for an increased number of days when the averaged 8-h ozone values exceed 70 ppb, with the highest sensitivity being in the central and midwestern United States, where most of the O&NG growth has occurred. These findings demonstrate that O&NG emissions significantly affect the air quality across most of the United States, can regionally offset reductions of ozone precursor emissions made in other sectors, and can have a determining influence on a region's ability to meet National Ambient Air Quality Standard (NAAQS) obligations for ozone.

Integration of absolute cardiovascular disease risk assessment into routine blood cholesterol testing at pathology services.

BACKGROUND: Absolute cardiovascular disease (CVD) risk assessment is recommended for primary prevention of CVD, yet uptake in general practice is limited. Cholesterol requests at pathology services provide an opportunity to improve uptake by integrating absolute CVD risk assessment with this service. OBJECTIVE: This study aimed to assess the feasibility of such an additional service. METHODS: Two-hundred and ninety-nine patients (45-74 years) referred to pathology services for blood cholesterol had measurement of all variables required to determine absolute CVD risk according to Framingham calculator (blood pressure, age, sex, smoking and diabetes status via self-report). Data were recorded via computer-based application. The absolute risk score was communicated via the report sent to the referring medical practitioner as per usual practice. Evaluation questionnaires were completed immediately post visit and at 1-, 3- and 6-month follow-up via telephone (n = 262). RESULTS: Absolute CVD risk reports were issued for 90% of patients. Most patients (95%) reported that the length of time for the pathology service assessment was acceptable, and 91% that the self-directed computer-based application was easy to use. Seventy-eight per cent reported a preference for pathology services to conduct absolute CVD risk assessment. Only 2% preferred a medical practitioner. Of follow-up patients, 202 (75%) had a consultation with a medical practitioner, during which, aspects of CVD risk prevention were discussed (cholesterol and blood pressure 74% and 69% of the time, respectively). CONCLUSIONS: Measurement of absolute CVD risk in pathology services is feasible, highly acceptable among middle-to-older adults and may increase uptake of guideline-directed care in general practice.

The influence of fitness on exercise blood pressure and its association with cardiac structure in adolescence.

PURPOSE: Exaggerated exercise blood pressure (BP) is associated with altered cardiac structure and increased cardiovascular risk. Fitness modifies these associations, but the effect in healthy adolescents is unknown. We performed an observational study to determine the influence of fitness on post-exercise BP, and on its relationship with cardiac structure in adolescents. METHODS: 4835 adolescents from the Avon Longitudinal Study of Parents and Children, (15.4 (0.3) years, 49% male) completed a submaximal cycle test. Fitness was estimated as physical work capacity 170 adjusted for lean body mass and post-exercise BP measured immediately posttest. Cardiovascular structure and function, including left ventricular (LV) mass (n = 1589), left atrium (LA) size (n = 1466), cardiac output (CO, n = 1610), and total peripheral resistance (TPR, n = 1610) were measured at rest by echocardiography 2.4 (0.4) years later. RESULTS: Post-exercise systolic BP increased stepwise by fitness tertile (131.2 mm Hg [130.4, 132.1]; 137.3 mm Hg [136.5, 138.0]; 142.3 mm Hg [141.5, 143.1]). Each 5 mm Hg of post-exercise systolic BP was associated with 2.46 g [1.91, 3.01] greater LV mass, 0.02 cm [0.02, 0.03] greater LA size, and 0.25 g/m2.7 [0.14, 0.36] greater LV mass index. Adjustment for fitness abolished associations (0.29 g [-0.16, 0.74]; 0.01 cm [-0.001, 0.014] and 0.08 g/m2.7 [-0.001, 0.002]). Similar associations between post-exercise systolic BP and each outcome were found between the lowest and highest fitness thirds. CO increased with fitness third (difference 0.06 L/min [-0.05, 0.17]; 0.23 L/min [0.12, 0.34]) while TPR decreased (difference -0.13 mm Hg·min/L [-0.84,0.59]; -1.08 mm Hg·min/L [-0.1.80, 0.35]). CONCLUSIONS: Post-exercise systolic BP increased with fitness, which modified its association with cardiac structure. Higher CO, but lower TPR suggests a physiologically adapted cardiovascular system with greater fitness, highlighting the importance of fitness in adolescence.

Masked hypertension and submaximal exercise blood pressure among adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC).

PURPOSE: Masked hypertension is associated with increased cardiovascular risk but is undetectable by clinic blood pressure (BP). Elevated systolic BP responses to submaximal exercise reveal the presence of masked hypertension in adults, but it is unknown whether this is the case during adolescence. We aimed to determine if exercise BP was raised in adolescents with masked hypertension, and its association with cardiovascular risk markers. METHODS: A total of 657 adolescents (aged 17.7 ± 0.3 years; 41.9% male) from the Avon longitudinal study of parents and children (ALSPAC) completed a step-exercise test with pre-, post-, and recovery-exercise BP, clinic BP and 24-hour ambulatory BP. Masked hypertension was defined as clinic BP <140/90 mm Hg and 24-hour ambulatory BP ≥130/80 mm Hg. Assessment of left-ventricular (LV) mass index and carotid-femoral pulse wave velocity (aortic PWV) was also undertaken. Thresholds of clinic, pre-, post-, and recovery-exercise systolic BP were explored from ROC analysis to identify masked hypertension. RESULTS: Fifty participants (7.8%) were classified with masked hypertension. Clinic, pre-, post-, and recovery-exercise systolic BP were associated with masked hypertension (AUC ≥ 0.69 for all, respectively), with the clinic systolic BP threshold of 115 mm Hg having high sensitivity and specificity and exercise BP thresholds of 126, 150, and 130 mm Hg, respectively, having high specificity and negative predictive value (individually or when combined) for ruling out the presence of masked hypertension. Additionally, this exercise systolic BP above the thresholds was associated with greater left-ventricular mass index and aortic PWV. CONCLUSIONS: Submaximal exercise systolic BP is associated with masked hypertension and adverse cardiovascular structure in adolescents. Exercise BP may be useful in addition to clinic BP for screening of high BP and cardiovascular risk in adolescents.

Influence of blood pressure level and age on within-visit blood pressure variability in children and adolescents.

Blood pressure (BP) is variable in children and this could affect BP assessment, but the magnitude of within-visit BP variability (BPV) over consecutive measurements has never been investigated. This study aimed to determine the direction and magnitude of, and factors affecting, within-visit BPV in children and adolescents. BP was recorded among 3047 children (aged 12 years [95%CI 12, 13], males 52%) from the 2011-2013 Australian Health Survey. BPV was defined as the absolute difference (∆SBPABS) between the first (SBP1) and second systolic BP (SBP2) and the overall variability in three measures when available (SBPV). On average, ∆SBPABS was 6.7 mmHg (95%CI 6.3, 7.0) and SBPV was 8.2% (95%CI 7.8, 8.6). ∆SBPABS was greater with higher BP levels but lower with older age. From first to second measurements, SBP decreased in 58% (95%CI 56, 60), did not change in 10% (95%CI 9, 12), and increased in 32% (95%CI 29, 34) of the population. CONCLUSIONS: BP is highly variable in children and adolescents, with the magnitude of variability being associated with both age and BP level. SBP increases on repeat measurement in a substantial proportion of the population. The optimal protocol of BP assessment to address this increased BPV needs to be determined. What is Known: • Diagnosis of elevated blood pressure (BP) is based on strict probabilistic criteria, the difference between the 90th (pre-hypertension) and 95th (hypertension) percentiles only being 3-4 mmHg. • BP variability could affect BP classification among children and adolescents. What is New: • The magnitude of BP change among children and adolescents is highly affected by BP level and age. • BP does not always drop on consecutive measurements, and evidence-based BP assessment protocols should be established to avoid misdiagnosis of hypertension.

Availability, Cost, and Consumer Ratings of Popular Nonvalidated vs Validated Blood Pressure-Measuring Devices Sold Online in 10 Countries.

This study examines the availability, cost, and consumer ratings of blood pressure­measuring devices relative to validation status across 10 countries.

Blood Pressure Response to Exercise and Cardiovascular Disease.

PURPOSE OF REVIEW: This review aimed to provide a clinical update on exercise blood pressure (BP) and its relationship to cardiovascular disease (CVD), outlining key determinants of abnormal exercise BP responses. We also highlight current evidence gaps that need addressing in order to optimise the relevance of exercise BP as clinical CVD risk factor. RECENT FINDINGS: Abnormal exercise BP manifests as either exercise hypotension (low BP response) or as exaggerated exercise BP (high BP response). Exercise hypotension is an established sign of existing and likely severe CVD, but exaggerated exercise BP also carries elevated CVD risk due to its association with sub-clinical hypertension. Although exaggerated exercise BP is related to heightened CVD risk at any exercise intensity, recent data suggest that the BP response to submaximal intensity exercise holds greater prognostic and clinical significance than BP achieved at peak/maximal intensity exercise. Cardiorespiratory fitness is a strong modifier of the exercise BP response, and should be taken into consideration when assessing the association with CVD. Both exercise hypotension and exaggerated exercise BP serve as markers that should prompt evaluation for potential underlying CVD. However, the clinical utility of these markers is currently inhibited by the lack of consensus informing the definitions and thresholds for abnormalities in exercise BP.

Associations and clinical relevance of aortic-brachial artery stiffness mismatch, aortic reservoir function, and central pressure augmentation.

Central augmentation pressure (AP) and index (AIx) predict cardiovascular events and mortality, but underlying physiological mechanisms remain disputed. While traditionally believed to relate to wave reflections arising from proximal arterial impedance (and stiffness) mismatching, recent evidence suggests aortic reservoir function may be a more dominant contributor to AP and AIx. Our aim was therefore to determine relationships among aortic-brachial stiffness mismatching, AP, AIx, aortic reservoir function, and end-organ disease. Aortic (aPWV) and brachial (bPWV) pulse wave velocity were measured in 359 individuals (aged 61 ± 9, 49% male). Central AP, AIx, and aortic reservoir indexes were derived from radial tonometry. Participants were stratified by positive (bPWV > aPWV), negligible (bPWV ≈ aPWV), or negative stiffness mismatch (bPWV < aPWV). Left-ventricular mass index (LVMI) was measured by two-dimensional-echocardiography. Central AP and AIx were higher with negative stiffness mismatch vs. negligible or positive stiffness mismatch (11 ± 6 vs. 10 ± 6 vs. 8 ± 6 mmHg, P < 0.001 and 24 ± 10 vs. 24 ± 11 vs. 21 ± 13%, P = 0.042). Stiffness mismatch (bPWV-aPWV) was negatively associated with AP (r = -0.18, P = 0.001) but not AIx (r = -0.06, P = 0.27). Aortic reservoir pressure strongly correlated to AP (r = 0.81, P < 0.001) and AIx (r = 0.62, P < 0.001) independent of age, sex, heart rate, mean arterial pressure, and height (standardized ß = 0.61 and 0.12, P ≤ 0.001). Aortic reservoir pressure independently predicted abnormal LVMI (ß = 0.13, P = 0.024). Positive aortic-brachial stiffness mismatch does not result in higher AP or AIx. Aortic reservoir function, rather than discrete wave reflection from proximal arterial stiffness mismatching, provides a better model description of AP and AIx and also has clinical relevance as evidenced by an independent association of aortic reservoir pressure with LVMI.

Aortic reservoir pressure corresponds to cyclic changes in aortic volume: physiological validation in humans.

OBJECTIVE: Aortic reservoir pressure indices independently predict cardiovascular events and mortality. Despite this, there has never been a study in humans to determine whether the theoretical principles of the mathematically derived aortic reservoir pressure (RP(derived)) and excess pressure (XP(derived)) model have a real physiological basis. This study aimed to directly measure the aortic reservoir (AR(direct); by cyclic change in aortic volume) and determine its relationship with RP(derived), XP(derived), and aortic blood pressure (BP). APPROACH AND RESULTS: Ascending aortic BP and Doppler flow velocity were recorded via intra-arterial wire in 10 men (aged 62 ± 12 years) during coronary artery bypass surgery. Simultaneous ascending aortic transesophageal echocardiography was used to measure AR(direct). Published mathematical formulae were used to determine RP(derived) and XP(derived). AR(direct) was strongly and linearly related to RP(derived) during systole (r=0.988; P<0.001) and diastole (r=0.985; P<0.001). Peak cross-correlation (r=0.98) occurred at a phase lag of 0.004 s into the cardiac cycle, suggesting close temporal agreement between waveforms. The relationship between aortic BP and AR(direct) was qualitatively similar to the cyclic relationship between aortic BP and RP(derived), with peak cross-correlations occurring at identical phase lags (AR(direct) versus aortic BP, r=0.96 at 0.06 s; RP(derived) versus aortic BP, r=0.98 at 0.06 s). CONCLUSIONS: RP(derived) is highly correlated with changes in proximal aortic volume, consistent with its physiological interpretation as corresponding to the instantaneous volume of blood stored in the aorta. Thus, aortic reservoir pressure should be considered in the interpretation of the central BP waveform.

Co-Designed Cardiac Rehabilitation for the Secondary Prevention of Stroke (CARESS): A Pilot Program Evaluation.

Structured health system-based programs, such as cardiac rehabilitation, may reduce the risk of recurrent stroke. This study aimed to co-design and evaluate a structured program of rehabilitation, developed based on insights from focus groups involving stroke survivors and health professionals. Conducted in Tasmania, Australia in 2019, the 7-week program comprised one hour of group exercise and one hour of education each week. Functional capacity (6 min walk test), fatigue, symptoms of depression (Patient Health Questionnaire), and lifestyle were assessed pre- and post-program, with a historical control group for comparison. Propensity score matching determined the average treatment effect (ATE) of the program. Key themes from the co-design focus groups included the need for coordinated care, improved psychosocial management, and including carers and peers in programs. Of the 23 people approached, 10 participants (70% men, mean age 67.4 ± 8.6 years) completed the program without adverse events. ATE analysis revealed improvements in functional capacity (139 m, 95% CI 44, 234) and fatigue (-5 units, 95% CI -9, -1), with a small improvement in symptoms of depression (-0.8 units, 95% CI -1.8, 0.2) compared to controls. The co-designed program demonstrated feasibility, acceptability, and positive outcomes, suggesting its potential to support stroke survivors.

Lifestyle management of hypertension: International Society of Hypertension position paper endorsed by the World Hypertension League and European Society of Hypertension.

Hypertension, defined as persistently elevated systolic blood pressure (SBP) >140 mmHg and/or diastolic blood pressure (DBP) at least 90 mmHg (International Society of Hypertension guidelines), affects over 1.5 billion people worldwide. Hypertension is associated with increased risk of cardiovascular disease (CVD) events (e.g. coronary heart disease, heart failure and stroke) and death. An international panel of experts convened by the International Society of Hypertension College of Experts compiled lifestyle management recommendations as first-line strategy to prevent and control hypertension in adulthood. We also recommend that lifestyle changes be continued even when blood pressure-lowering medications are prescribed. Specific recommendations based on literature evidence are summarized with advice to start these measures early in life, including maintaining a healthy body weight, increased levels of different types of physical activity, healthy eating and drinking, avoidance and cessation of smoking and alcohol use, management of stress and sleep levels. We also discuss the relevance of specific approaches including consumption of sodium, potassium, sugar, fibre, coffee, tea, intermittent fasting as well as integrated strategies to implement these recommendations using, for example, behaviour change-related technologies and digital tools.

Accuracy of cuff blood pressure and systolic blood pressure amplification.

Automated cuff measured blood pressure (BP) is the global standard used for diagnosing hypertension, but there are concerns regarding the accuracy of the method. Individual variability in systolic BP (SBP) amplification from central (aorta) to peripheral (brachial) arteries could be related to the accuracy of cuff BP, but this has never been determined and was the aim of this study. Automated cuff BP and invasive brachial BP were recorded in 795 participants (74% male, aged 64 ± 11 years) receiving coronary angiography at five independent research sites (using seven different automated cuff BP devices). SBP amplification was recorded invasively by catheter and defined as brachial SBP minus aortic SBP. Compared with invasive brachial SBP, cuff SBP was significantly underestimated (130 ± 18 mmHg vs. 138 ± 22 mmHg, p < 0.001). The level of SBP amplification varied significantly among individuals (mean ± SD, 7.3 ± 9.1 mmHg) and was similar to level of difference between cuff and invasive brachial SBP (mean difference -7.6 ± 11.9 mmHg). SBP amplification explained most of the variance in accuracy of cuff SBP (R2 = 19%). The accuracy of cuff SBP was greatest among participants with the lowest SBP amplification (ptrend < 0.001). After cuff BP values were corrected for SBP amplification, there was a significant improvement in the mean difference from the intra-arterial standard (p < 0.0001) and in the accuracy of hypertension classification according to 2017 ACC/AHA guideline thresholds (p = 0.005). The level of SBP amplification is a critical factor associated with the accuracy of conventional automated cuff measured BP.

Cardiovascular and health cost impacts of cuff blood pressure underestimation and overestimation of invasive aortic systolic blood pressure.

OBJECTIVE: Hypertension management is directed by cuff blood pressure (BP), but this may be inaccurate, potentially influencing cardiovascular disease (CVD) events and health costs. This study aimed to determine the impact on CVD events and related costs of the differences between cuff and invasive SBP. METHODS: Microsimulations based on Markov modelling over one year were used to determine the differences in the number of CVD events (myocardial infarction or coronary death, stroke, atrial fibrillation or heart failure) predicted by Framingham risk and total CVD health costs based on cuff SBP compared with invasive (aortic) SBP. Modelling was based on international consortium data from 1678 participants undergoing cardiac catheterization and 30 separate studies. Cuff underestimation and overestimation were defined as cuff SBP less than invasive SBP and cuff SBP greater than invasive SBP, respectively. RESULTS: The proportion of people with cuff SBP underestimation versus overestimation progressively increased as SBP increased. This reached a maximum ratio of 16 : 1 in people with hypertension grades II and III. Both the number of CVD events missed (predominantly stroke, coronary death and myocardial infarction) and associated health costs increased stepwise across levels of SBP control, as cuff SBP underestimation increased. The maximum number of CVD events potentially missed (11.8/1000 patients) and highest costs ($241 300 USD/1000 patients) were seen in people with hypertension grades II and III and with at least 15 mmHg of cuff SBP underestimation. CONCLUSION: Cuff SBP underestimation can result in potentially preventable CVD events being missed and major increases in health costs. These issues could be remedied with improved cuff SBP accuracy.