Time-domain heart rate variability features for automatic congestive heart failure prediction

AIMS

Heart failure is a serious condition that often goes undiagnosed in primary care due to the lack of reliable diagnostic tools and the similarity of its symptoms with other diseases. Non-invasive monitoring of heart rate variability (HRV), which reflects the activity of the autonomic nervous system, could offer a novel and accurate way to detect and manage heart failure patients. This study aimed to assess the feasibility of using machine learning techniques on HRV data as a non-invasive biomarker to classify healthy adults and those with heart failure.

METHODS AND RESULTS

We used digitized electrocardiogram recordings from 54 adults with normal sinus rhythm and 44 adults categorized into New York Heart Association classes 1, 2, and 3, suffering from congestive heart failure. All recordings were sourced from the PhysioNet database. Following data pre-processing, we performed time-domain HRV analysis on all individual recordings, including root mean square of the successive difference in adjacent RR interval (RRi) (RMSSD), the standard deviation of RRi (SDNN, the NN stands for natural or sinus intervals), the standard deviation of the successive differences between successive RRi (SDSD), the number or percentage of RRi longer than 50 ms (NN50 and pNN50), and the average value of RRi [mean RR interval (mRRi)]. In our experimental classification performance evaluation, on the computed HRV parameters, we optimized hyperparameters and performed five-fold cross-validation using four machine learning classification algorithms: support vector machine, k-nearest neighbour (KNN), naïve Bayes, and decision tree (DT). We evaluated the prediction accuracy of these models using performance criteria, namely, precision, recall, specificity, F1 score, and overall accuracy. For added insight, we also presented receiver operating characteristic (ROC) plots and area under the ROC curve (AUC) values. The overall best performance accuracy of 77% was achieved when KNN and DT were trained on computed HRV parameters with a 5 min time window. KNN obtained an AUC of 0.77, while DT attained 0.78. Additionally, in the classification of severe congestive heart failure, KNN and DT had the best accuracy of 91%, with KNN achieving an AUC of 0.88 and DT obtaining 0.92.

CONCLUSIONS

The results show that HRV can accurately predict severe congestive heart failure. The findings of this study could inform the use of machine learning approaches on non-invasive HRV, to screen congestive heart failure individuals in primary care.

Impact of Fruit and Fruit Juice on Death and Disease Incidence: A Sex-Specific Longitudinal Analysis of 18 603 Adults

BACKGROUND

The health benefits of fruits are well established, but fruit juice has been more controversial. Fruit and juice are often ingested with other foods, which prompted our investigation to determine whether fruit consumed as juice may negate the beneficial effects of consuming whole fruit in people with cardiovascular disease.

METHODS AND RESULTS

We retrospectively analyzed data from a population-based study in Australia (the 45 and Up Study) linked with hospitalization and mortality data up to September 2018. Kaplan-Meier survival estimates and Cox proportional hazards models were used to examine effects of fruit, fruit juice, and the combination of fruit and fruit juice in relation to death and disease incidence among men and women living with cardiovascular disease. A total of 7308 deaths occurred among 18 603 participants diagnosed with cardiovascular disease over a 13-year follow-up. After multivariable adjustment, inadequate fruit intake (hazard ratio [HR], 1.12 [95% CI, 1.01-1.24]) and high fruit juice intake (HR, 1.26 [95% CI, 1.12-1.41]) predicted all-cause mortality in women. Also, high fruit juice intake plus either adequate fruit intake (HR, 1.18 [95% CI, 1.02-1.37]) or inadequate fruit intake (HR, 1.43 [95% CI, 1.21-1.69]) predicted mortality in women. No relationships were found in men after multivariable adjustments. Also, we found no prognostic value for fruit and fruit juice intake on disease incidence.

CONCLUSIONS

In adults with cardiovascular disease, we found that fruit juice (in combination with adequate or inadequate fruit intake) predicted mortality in women but not in men. These effects became less clear when focusing on disease incidence.

Excess Bed Days and Hospitalization Costs Associated With 30-Day Complications Following Catheter Ablation of Atrial Fibrillation

BACKGROUND

The incidence and type of complications following catheter ablation of atrial fibrillation have been extensively examined, but the impact associated with these complications on the length of stay and hospitalization costs is unknown.

METHODS AND RESULTS

This cohort study included 20 117 adult patients (mean age 62.6±11.4 years, 30.3% women, median length of stay 1 day [interquartile range 1-2 days]) undergoing atrial fibrillation ablation in financial years 2011 to 2017 in Australia with available cost data from the National Hospital Cost Data Collection, which determines government reimbursement of health services provided. The primary outcome was the costs associated with complications occurring up to 30 days postdischarge adjusted for inflation to 2021 Australian dollars. We used generalized linear models to estimate the increase in length of stay and cost associated with complications, adjusting for patient characteristics. Within 30 days of hospital discharge, 1151 (5.72%) patients experienced a complication with bleeding (3.35%) and pericardial effusion (0.75%) being the most common. On average, the occurrence of a complication was associated with an adjusted 3.3 (95% CI, 3.1-3.6) excess bed days of hospital care (totaling 3851 days), and a $7812 (95% CI, $6754-$8870) increase in hospitalization cost (totaling $9.0 million). Most of the total excess cost was attributable to bleeding ($3.8 million, 41.9% of total excess cost) and pericardial effusion ($1.6 million, 18.2%).

CONCLUSIONS

Complications following atrial fibrillation ablation were associated with significant increase in length of stay and hospitalization costs, most of which were attributable to bleeding and pericardial effusion. Strategies to improve procedural safety and reduce health care costs should focus on these complications.

Parent-reported compared with researcher-measured child height and weight: impact on body mass index classification in Australian pre-school aged children

ISSUE ADDRESSED

Parent-reported data may provide a practical and cheap way for estimating young children's weight status. This study aims to compare the validity and reliability of parent-reported height and weight to researcher-measured data for pre-school aged children (aged 2-6 years).

METHODS

This was a nested study within a cluster randomised controlled trial (October 2016-April 2017), conducted within 32 Early Childhood Education and Care (ECEC) services across New South Wales, Australia. Parents of children reported on demographics and child height and weight via a survey. For the same child, height and weight data were objectively collected by trained research staff at the service. We calculated mean differences, intra-class correlations, Bland-Altman plots, percentage agreement and Cohen's kappa coefficient (>0.8 = "excellent"; 0.61-0.8 = "good"; 0.41-0.60 = "moderate"; 0.21 and 0.4 = "fair [weak]"; <0.2 = "poor").

RESULTS

Overall, 89 children were included (mean age: 4.7 years; 59.5% female). The mean difference between parent-reported and researcher-measured data were small (BMI z-score: mean difference -0.01 [95% CI: -0.45 to 0.44]). There was "fair/weak" agreement between parent-categorised child BMI compared with researcher-measured data (Cohen's Kappa 0.24 [95% CI: 0.06 to 0.42]). Agreement was poor (Cohen's kappa <0.2) for female children, when reported by fathers or by parents with a BMI > 25 kg/m2 .

CONCLUSION

There was "fair/weak" agreement between parent-reported and measured estimates of child weight status. SO WHAT?: Parent's report of weight and height may be a weak indicator of adiposity at the level of individuals however it may be useful for aggregate estimates.

Renal arterial infusion of tempol prevents medullary hypoperfusion, hypoxia, and acute kidney injury in ovine Gram-negative sepsis

AIM

Renal medullary hypoperfusion and hypoxia precede acute kidney injury (AKI) in ovine sepsis. Oxidative/nitrosative stress, inflammation, and impaired nitric oxide generation may contribute to such pathophysiology. We tested whether the antioxidant and anti-inflammatory drug, tempol, may modify these responses.

METHODS

Following unilateral nephrectomy, we inserted renal arterial catheters and laser-Doppler/oxygen-sensing probes in the renal cortex and medulla. Noanesthetized sheep were administered intravenous (IV) Escherichia coli and, at sepsis onset, IV tempol (IVT; 30 mg kg-1  h-1 ), renal arterial tempol (RAT; 3 mg kg-1  h-1 ), or vehicle.

RESULTS

Septic sheep receiving vehicle developed renal medullary hypoperfusion (76 ± 16% decrease in perfusion), hypoxia (70 ± 13% decrease in oxygenation), and AKI (87 ± 8% decrease in creatinine clearance) with similar changes during IVT. However, RAT preserved medullary perfusion (1072 ± 307 to 1005 ± 271 units), oxygenation (46 ± 8 to 43 ± 6 mmHg), and creatinine clearance (61 ± 10 to 66 ± 20 mL min-1 ). Plasma, renal medullary, and cortical tissue malonaldehyde and medullary 3-nitrotyrosine decreased significantly with sepsis but were unaffected by IVT or RAT. Consistent with decreased oxidative/nitrosative stress markers, cortical and medullary nuclear factor-erythroid-related factor-2 increased significantly and were unaffected by IVT or RAT. However, RAT prevented sepsis-induced overexpression of cortical tissue tumor necrosis factor alpha (TNF-α; 51 ± 16% decrease; p = 0.003) and medullary Thr-495 phosphorylation of endothelial nitric oxide synthase (eNOS; 63 ± 18% decrease; p = 0.015).

CONCLUSIONS

In ovine Gram-negative sepsis, renal arterial infusion of tempol prevented renal medullary hypoperfusion and hypoxia and AKI and decreased TNF-α expression and uncoupling of eNOS. However, it did not affect markers of oxidative/nitrosative stress, which were significantly decreased by Gram-negative sepsis.

Evidence supporting the choice of a new cardiovascular risk equation for Australia

This article reviews the risk equations recommended for use in international cardiovascular disease (CVD) primary prevention guidelines and assesses their suitability for use in Australia against a set of a priori defined selection criteria. The review and assessment were commissioned by the National Heart Foundation of Australia on behalf of the Australian Chronic Disease Prevention Alliance to inform recommendations on CVD risk estimation as part of the 2023 update of the Australian CVD risk assessment and management guidelines. Selected international risk equations were assessed against eight selection criteria: development using contemporary data; inclusion of established cardiovascular risk factors; inclusion of ethnicity and deprivation measures; prediction of a broad selection of fatal and non-fatal CVD outcomes; population representativeness; model performance; external validation in an Australian dataset; and the ability to be recalibrated or modified. Of the ten risk prediction equations reviewed, the New Zealand PREDICT equation met seven of the eight selection criteria, and met additional usability criteria aimed at assessing the ability to apply the risk equation in practice in Australia.

Biomembrane force probe (BFP): Design, advancements, and recent applications to live-cell mechanobiology

Mechanical forces play a vital role in biological processes at molecular and cellular levels, significantly impacting various diseases such as cancer, cardiovascular disease, and COVID-19. Recent advancements in dynamic force spectroscopy (DFS) techniques have enabled the application and measurement of forces and displacements with high resolutions, providing crucial insights into the mechanical pathways underlying these diseases. Among DFS techniques, the biomembrane force probe (BFP) stands out for its ability to measure bond kinetics and cellular mechanosensing with pico-newton and nano-meter resolutions. Here, a comprehensive overview of the classical BFP-DFS setup is presented and key advancements are emphasized, including the development of dual biomembrane force probe (dBFP) and fluorescence biomembrane force probe (fBFP). BFP-DFS allows us to investigate dynamic bond behaviors on living cells and significantly enhances the understanding of specific ligand-receptor axes mediated cell mechanosensing. The contributions of BFP-DFS to the fields of cancer biology, thrombosis, and inflammation are delved into, exploring its potential to elucidate novel therapeutic discoveries. Furthermore, future BFP upgrades aimed at improving output and feasibility are anticipated, emphasizing its growing importance in the field of cell mechanobiology. Although BFP-DFS remains a niche research modality, its impact on the expanding field of cell mechanobiology is immense.

Healthy lifestyles are associated with better vitamin D status in community-dwelling older men: The Health In Men Study (HIMS)

OBJECTIVE

Older people are more prone to vitamin D deficiency than younger populations. Individual lifestyle factors have been associated with vitamin D status. We examined the influence of a combination of lifestyle factors on vitamin D status in older men.

PARTICIPANTS AND MEASUREMENTS

In a population-based cohort study of older men (age ≥65 years), a lifestyle score was calculated from eight prudent health-related behaviours (smoking, exercise, alcohol, fish and meat consumption, adding salt, milk choices and obesity) collected via questionnaire at baseline. Blood samples were collected 5 years afterwards to measure plasma 25-hydroxyvitamin D (25OHD) levels. Associations between lifestyles and the likelihood of having plasma 25OHD levels of ≥75 versus <75 nmol/L and ≥50 versus <50 nmol/L were tested using logistic regression models.

RESULTS

Of the 2717 men analysed, mean plasma 25OHD was 69.0 ± 23.5 nmol/L, with 20.7% having plasma 25OHD <50 nmol/L. Men engaging in ≥4 healthy lifestyle behaviours had 20% higher odds of plasma 25OHD ≥75 nmol/L (adjusted OR = 1.20, 95% CI: 1.01-1.45) compared to those with <4 healthy behaviours. No association was found for 25OHD ≥50 nmol/L. Higher physical activity was the only individual component significantly associated with vitamin D sufficiency (highest vs. lowest quintiles of physical activity, adjusted OR = 2.01, 95% CI: 1.47-2.74 for 25OHD ≥50 nmol/L, adjusted OR = 2.35, 95% CI: 1.81-3.06 for 25OHD ≥75 nmol/L).

CONCLUSION

Multiple healthy lifestyle behaviours are associated with better vitamin D status in older men. Further work is needed to determine the effects of promoting healthy lifestyle behaviours, including physical activity, on vitamin D sufficiency.

State of Shock: Contemporary Vasopressor and Inotrope Use in Cardiogenic Shock

Cardiogenic shock is characterized by tissue hypoxia caused by circulatory failure arising from inadequate cardiac output. In addition to treating the pathologic process causing impaired cardiac function, prompt hemodynamic support is essential to reduce the risk of developing multiorgan dysfunction and to preserve cellular metabolism. Pharmacologic therapy with the use of vasopressors and inotropes is a key component of this treatment strategy, improving perfusion by increasing cardiac output, altering systemic vascular resistance, or both, while allowing time and hemodynamic stability to treat the underlying disease process implicated in the development of cardiogenic shock. Despite the use of mechanical circulatory support recently garnering significant interest, pharmacologic hemodynamic support remains a cornerstone of cardiogenic shock management, with over 90% of patients receiving at least 1 vasoactive agent. This review aims to describe the pharmacology and hemodynamic effects of current pharmacotherapies and provide a practical approach to their use, while highlighting important future research directions.

Small molecule allosteric modulation of the adenosine A1 receptor

G protein-coupled receptors (GPCRs) represent the target for approximately a third of FDA-approved small molecule drugs. The adenosine A₁ receptor (A₁R), one of four adenosine GPCR subtypes, has important (patho)physiological roles in humans. A₁R has well-established roles in the regulation of the cardiovascular and nervous systems, where it has been identified as a potential therapeutic target for a number of conditions, including cardiac ischemia-reperfusion injury, cognition, epilepsy, and neuropathic pain. A₁R small molecule drugs, typically orthosteric ligands, have undergone clinical trials. To date, none have progressed into the clinic, predominantly due to dose-limiting unwanted effects. The development of A₁R allosteric modulators that target a topographically distinct binding site represent a promising approach to overcome current limitations. Pharmacological parameters of allosteric ligands, including affinity, efficacy and cooperativity, can be optimized to regulate A₁R activity with high subtype, spatial and temporal selectivity. This review aims to offer insights into the A₁R as a potential therapeutic target and highlight recent advances in the structural understanding of A₁R allosteric modulation.

Volume adaptation of neonatal cardiomyocyte spheroids in 3D stiffness gradient GelMA

Present understandings of cardiomyocyte mechanobiology have primarily been developed using 2-dimensional, monocellular cell cultures, however the emergence of 3-dimensional (3D) multicellular cardiac constructs has enabled us to develop more sophisticated recapitulations of the cardiac microenvironment. Several of these strategies have illustrated that incorporating elements of the extracellular matrix (ECM) can promote greater maturation and enhance desirable cardiac functions, such as contractility, but the responses of these cardiac constructs to biophysically aberrant conditions, such as in the post-infarct heart, has remained relatively unexplored. In our study, we employ a stiffness gradient gelatin methacryloyl (GelMA) hydrogel platform to unpack the mechanobiology of cardiac spheroids. We encapsulated neonatal rat cardiac cell spheroids in a 4.4-18.7 kPa linear stiffness gradient up to 120 h. We found the proportion of viable cells within the spheroids increased over time, but the cell number per spheroid decreased. Spheroids expand more in softer matrices while stiffer matrices promote larger nuclei without changing nuclei shape. Volume expansion came primarily from cells expressing vimentin. We did not observe any correlations between stiffness and mechanomarker expression, however we found that after 120 h post-encapsulation, the localization of YAP, the localization of MRTF-A and the expression of Lamin-A was correlated with spheroid morphology. The same trends were not observed 24 h post-encapsulation, indicating that volume adaptation can take a relatively long time. Our data demonstrates that cardiac spheroids are mechanosensitive and that their capacity to respond to ECM-based cues depends on their capacity to adapt their volume with a 3D microenvironment.

The implementation and effectiveness of outlet-level healthy food and beverage accreditation schemes: A systematic review

Healthy food outlet accreditation schemes represent an avenue for incentivizing food retailers to promote healthy eating patterns by improving the healthiness of food environments. This systematic review aimed to (i) assess the impact of food outlet-level accreditation schemes on outlet practices and customer purchases and (ii) identify barriers and enablers to scheme implementation. Peer-reviewed and grey literature were systematically searched. Eligible studies related to outlet-level food and beverage accreditation schemes across any food retail setting. Findings were narratively synthesized by retailer type according to (i) scheme characteristics (governance, targeted products, support, and monitoring); (ii) scheme outcomes (rate of uptake, proportion of certified retailers, impact on purchasing, customer perspectives, and retailer perspectives); and (iii) barriers and enablers to implementation. From 21,943 records screened, 48 were included, covering 26 schemes. Most (18) targeted restaurants or convenience stores. Average uptake was 65% of all outlets approached to participate. Implementation of accreditation schemes was associated with healthier customer purchases in convenience stores, schools, and hospitals, but evidence from restaurants was mixed. Enablers of scheme implementation included support for implementation and maintenance, flexible scheme criteria, and motivated retail staff. Healthy food outlet accreditation schemes represent a promising mechanism for engaging retailers to improve the healthiness of food retail environments.

The effects of recruitment of renal functional reserve on renal cortical and medullary oxygenation in non-anesthetized sheep

AIM

Recruitment of renal functional reserve (RFR) with amino acid loading increases renal blood flow and glomerular filtration rate. However, its effects on renal cortical and medullary oxygenation have not been determined. Accordingly, we tested the effects of recruitment of RFR on renal cortical and medullary oxygenation in non-anesthetized sheep.

METHODS

Under general anesthesia, we instrumented 10 sheep to enable subsequent continuous measurements of systemic and renal hemodynamics, renal oxygen delivery and consumption, and cortical and medullary tissue oxygen tension (PO2 ). We then measured the effects of recruitment of RFR with an intravenous infusion of 500 ml of a clinically used amino acid solution (10% Synthamin® 17) in the non-anesthetized state.

RESULTS

Compared with baseline, Synthamin® 17 infusion significantly increased renal oxygen delivery mean ± SD maximum increase: (from 0.79 ± 0.17 to 1.06 ± 0.16 ml/kg/min, p < 0.001), renal oxygen consumption (from 0.08 ± 0.01 to 0.15 ± 0.02 ml/kg/min, p < 0.001), and glomerular filtration rate (+45.2 ± 2.7%, p < 0.001). Renal cortical tissue PO2 increased by a maximum of 26.4 ± 1.1% (p = 0.001) and medullary tissue PO2 increased by a maximum of 23.9 ± 2.8% (p = 0. 001).

CONCLUSIONS

In non-anesthetized healthy sheep, recruitment of RFR improved renal cortical and medullary oxygenation. These observations might have implications for the use of recruitment of RFR for diagnostic and therapeutic purposes.

Acute exercise and high-glucose ingestion elicit dynamic and individualized responses in systemic markers of redox homeostasis

Background

Biomarkers of oxidation-reduction (redox) homeostasis are commonly measured in human blood to assess whether certain stimuli (e.g., high-glucose ingestion or acute exercise) lead to a state of oxidative distress (detrimental to health) or oxidative eustress (beneficial to health). Emerging research indicates that redox responses are likely to be highly individualized, yet few studies report individual responses. Furthermore, the effects of complex redox stimuli (e.g., high-glucose-ingestion after exercise) on redox homeostasis remains unclear. We investigated the effect of acute exercise (oxidative eustress), high-glucose ingestion (oxidative distress), and high-glucose ingestion after exercise (both oxidative eu/distress), on commonly measured redox biomarkers in serum/plasma.

Methods

In a randomized crossover fashion, eight healthy men (age: 28 ± 4 years; BMI: 24.5 ± 1.5 kg/m2 [mean ± SD]) completed two separate testing conditions; 1) consumption of a high-glucose mixed-nutrient meal (45% carbohydrate [1.1 g glucose.kg-1], 20% protein, and 35% fat) at rest (control trial), and 2) consumption of the same meal 3 h and 24 h after 1 h of moderate-intensity cycling exercise (exercise trial). Plasma and serum were analyzed for an array of commonly studied redox biomarkers.

Results

Oxidative stress and antioxidant defense markers (hydrogen peroxide, 8-isoprostanes, catalase, superoxide dismutase, and nitrate levels) increased immediately after exercise (p &lt; 0.05), whereas nitric oxide activity and thiobarbituric acid reactive substances (TBARS) remained similar to baseline (p &gt; 0.118). Nitric oxide activity and nitrate levels decreased at 3 h post-exercise compared to pre-exercise baseline levels. Depending on when the high-glucose mixed nutrient meal was ingested and the postprandial timepoint investigated, oxidative stress and antioxidant defense biomarkers either increased (hydrogen peroxide, TBARS, and superoxide dismutase), decreased (hydrogen peroxide, 8-isoprostanes, superoxide dismutase, nitric oxide activity, nitrate, and nitrite), or remained similar to pre-meal baseline levels (hydrogen peroxide, 8-isoprostanes, TBARS, catalase, superoxide dismutase and nitrite). Redox responses exhibited large inter-individual variability in the magnitude and/or direction of responses.

Conclusion

Findings highlight the necessity to interpret redox biomarkers in the context of the individual, biomarker measured, and stimuli observed. Individual redox responsiveness may be of physiological relevance and should be explored as a potential means to inform personalized redox intervention.

Evidence of low vitamin D intakes in the Australian population points to a need for data-driven nutrition policy for improving population vitamin D status

BACKGROUND

Nearly one in four Australian adults is vitamin D deficient (serum 25-hydroxyvitamin D concentrations [25(OH)D] < 50 nmol L-1 ) and current vitamin D intakes in the Australian population are unknown. Internationally, vitamin D intakes are commonly below recommendations, although estimates generally rely on food composition data that do not include 25(OH)D. We aimed to estimate usual vitamin D intakes in the Australian population.

METHODS

Nationally representative food consumption data were collected for Australians aged ≥ 2 years (n = 12,153) as part of the cross-sectional 2011-2013 Australian Health Survey (AHS). New analytical vitamin D food composition data for vitamin D3 , 25(OH)D3 , vitamin D2 and 25(OH)D2 were mapped to foods and beverages that were commonly consumed by AHS participants. Usual vitamin D intakes (µg day-1 ) by sex and age group were estimated using the National Cancer Institute method.

RESULTS

Assuming a 25(OH)D bioactivity factor of 1, mean daily intakes of vitamin D ranged between 1.84 and 3.25 µg day-1 . Compared to the estimated average requirement of 10 µg day-1 recommended by the Institute of Medicine, more than 95% of people had inadequate vitamin D intakes. We estimated that no participant exceeded the Institute of Medicine's Upper Level of Intake (63-100 µg day-1 , depending on age group).

CONCLUSIONS

Usual vitamin D intakes in Australia are low. This evidence, paired with the high prevalence of vitamin D deficiency in Australia, suggests that data-driven nutrition policy is required to safely increase dietary intakes of vitamin D and improve vitamin D status at the population level.

Epidemiology, outcomes and predictors of mortality in patients transported by ambulance for dyspnoea: A population-based cohort study

OBJECTIVES

There are currently limited data to inform the management of patients transported by emergency medical services (EMS) with dyspnoea. We aimed to describe the incidence, aetiology and outcomes of patients transported by EMS for dyspnoea using a large population-based sample and to identify factors associated with 30-day mortality.

METHODS

Consecutive EMS attendances for dyspnoea in Victoria, Australia from January 2015 to June 2019 were included. Data were individually linked to hospital and mortality records to determine incidence, diagnoses, and outcomes. Factors associated with 30-day mortality were assessed using multivariable logistic regression.

RESULTS

During the study period, there were 2 505 324 cases attended by EMS, of whom 346 228 (14%) met inclusion criteria for dyspnoea. The incidence of EMS attendances for dyspnoea was 1566 per 100 000 person-years, and was higher in females, older patients and socially disadvantaged areas. Of the 271 204 successfully linked cases (median age 76 years; 51% women), 79% required hospital admission with a 30-day mortality of 9%. The most common final diagnoses (and 30-day mortality rates) were lower respiratory tract infection (13%, mortality 11%), chronic obstructive pulmonary disease (13%, mortality 6.4%), heart failure (9.1%, mortality 9.8%), arrhythmias (3.9%, mortality 4.4%), acute coronary syndromes (3.9%, mortality 9.5%) and asthma (3.2%, mortality 0.5%). Predictors of mortality included older age, male sex, pre-existing chronic kidney disease, heart failure or cancer, abnormal respiratory status or vital signs and pre-hospital intubation.

CONCLUSION

Dyspnoea is a common presentation with a broad range of causes and is associated with high rates of hospitalisation and death.

Is the cost-effectiveness of an early-childhood sleep intervention to prevent obesity affected by socioeconomic position?

OBJECTIVE

This study aimed to determine whether the cost-effectiveness of an infant sleep intervention from the Prevention of Overweight in Infancy (POI) trial was influenced by socioeconomic position (SEP).

METHODS

An SEP-specific economic evaluation of the sleep intervention was conducted. SEP-specific intervention costs and effects at age 5 years, derived from the trial data, were applied to a representative cohort of 4,898 4- to 5-year-old Australian children. Quality-adjusted life years and health care costs were simulated until age 17 years using a purpose-built SEP-specific model. Incremental cost-effectiveness ratios and acceptability curves were derived for each SEP group.

RESULTS

The incremental cost-effectiveness ratios, in Australian dollars per quality-adjusted life year gained, were smaller in the low- ($23,010) and mid-SEP ($18,206) groups compared with the high-SEP group ($31,981). The probability that the intervention was cost-effective was very high in the low- and mid-SEP groups (92%-100%) and moderately high in the high-SEP group (79%).

CONCLUSIONS

An infant sleep intervention is more cost-effective in low- and mid-SEP groups compared with high-SEP groups. Targeting this intervention to low-SEP groups would not require trade-offs between efficiency and equity.

Sex hormones, intestinal inflammation, and the gut microbiome: Major influencers of the sexual dimorphisms in obesity

Obesity is defined as the excessive accumulation of body fat and is associated with an increased risk of developing major health problems such as cardiovascular disease, diabetes and stroke. There are clear sexual dimorphisms in the epidemiology, pathophysiology and sequelae of obesity and its accompanying metabolic disorders, with females often better protected compared to males. This protection has predominantly been attributed to the female sex hormone estrogen and differences in fat distribution. More recently, the sexual dimorphisms of obesity have also been attributed to the differences in the composition and function of the gut microbiota, and the intestinal immune system. This review will comprehensively summarize the pre-clinical and clinical evidence for these sexual dimorphisms and discuss the interplay between sex hormones, intestinal inflammation and the gut microbiome in obesity. Major gaps and limitations of this rapidly growing area of research will also be highlighted in this review.

A single dose of noradrenergic/serotonergic reuptake inhibitors combined with an antimuscarinic does not improve obstructive sleep apnoea severity

Previous trials have demonstrated that the combination of noradrenergic reuptake inhibitors with an antimuscarinic can substantially reduce the apnoea-hypopnoea index (AHI) and improve airway collapsibility in patients with obstructive sleep apnoea (OSA). However, some studies have shown that when administered individually, neither noradrenergic or serotonergic agents have been effective at alleviating OSA. This raises the possibility that serotonergic agents (like noradrenergic agents) may also need to be delivered in combination to be efficacious. Therefore, we investigated the effect of an antimuscarinic (oxybutynin) on OSA severity when administered with either duloxetine or milnacipran, two dual noradrenergic/serotonergic reuptake inhibiters. A randomized, double-blind, 4 way cross-over, placebo-controlled trial in ten OSA patients was performed. Patients received each drug condition separately across four overnight in-lab polysomnography (PSG) studies ~1-week apart. The primary outcome measure was the AHI. In addition, the four key OSA endotypes (collapsibility, muscle compensation, arousal threshold, loop gain) were measured non-invasively from the PSGs using validated techniques. There was no significant effect of either drug combinations on reducing the total AHI or improving any of the key OSA endotypes. However, duloxetine+oxybutynin did significantly increase the fraction of hypopnoeas to apnoeas (F_Hypopnoea ) compared to placebo (p = 0.02; d = 0.54). In addition, duloxetine+oxybutynin reduced time in REM sleep (p = 0.009; d = 1.03) which was positively associated with a reduction in the total AHI (R²  = 0.62; p = 0.02). Neither drug combination significantly improved OSA severity or modified the key OSA endotypes when administered as a single dose to unselected OSA patients.

Clinical management of pregnancy in women with polycystic ovary syndrome: An expert opinion

Polycystic ovary syndrome (PCOS) is associated with a higher risk for pregnancy and birth complications according to the specific features associated with PCOS. The features include obesity before and during pregnancy, hyperandrogenism, insulin resistance, infertility, cardiometabolic risk factors, and poor mental health. PCOS is not often recognized as a risk factor for poor pregnancy and birth outcomes in pregnancy care guidelines, while its associated features are. Pregnancy-related risk profile should ideally be assessed for modifiable risk factors (e.g., lifestyle and weight management) at preconception in women with PCOS. Hyperglycaemia should be screened using a 75-g oral glucose tolerance test at preconception or within the first 20 weeks of pregnancy if it has not been performed at preconception and should be repeated at 24-28 weeks of pregnancy. In the absence of evidence of benefit for strategies specific to women with PCOS, the international evidence-based guidelines for the assessment and management of PCOS recommend screening, optimizing, and monitoring risk profile in women with PCOS (at preconception, during and postpregnancy) consistent with the recommendations for the general population. Recommended factors include blood glucose, weight, blood pressure, smoking, alcohol, diet, exercise, sleep and mental health, emotional, and sexual health among women with PCOS. The guidelines recommend Metformin in addition to lifestyle for assisting with weight management and improving cardiometabolic risk factors, particularly in those with overweight or obesity. Letrozole is considered the first-line pharmacological treatment for anovulatory infertility in PCOS. Individualized approach should be considered in the management of pregnancy in PCOS.

Smoking and quitting characteristics of Aboriginal and Torres Strait Islander women of reproductive age: findings from the Which Way? study

OBJECTIVE

To describe smoking characteristics, quitting behaviour and other factors associated with longest quit attempt and the use of nicotine replacement therapy (NRT) and stop-smoking medication (SSM) in a population of Indigenous Australian women of reproductive age.

DESIGN, SETTING AND PARTICIPANTS

A national cross-sectional survey of Aboriginal and Torres Strait Islander women aged 16-49 years who were smokers or ex-smokers was conducted online during the period July to October 2020.

MAIN OUTCOME MEASURES

Quitting experience: attempt to cut down, time since last quit attempt, longest period without smoking, attempt to cut down during last quit attempt, any use of NRT and/or SSM.

RESULTS

Most of the 428 participating women (302 [70.6%]) reported using an Aboriginal health service. Younger women (16-20-year-olds) smoked fewer cigarettes daily (24/42 [57.1%], 0-5 cigarettes per day), waited longer to smoke after waking (20/42 [47.6%], > 60 minutes after waking), and were categorised as low smoking dependency compared with those aged 35 years and over. One-third of women (153 [35.7%]) had ever used NRT and/or SSM. A greater proportion of older women (35-49-year-olds) had sustained a quit attempt for years (62/149 [45.6%]) and reported trying NRT and/or SSM (78/149 [52.4%]) than women in younger age groups. Quitting suddenly rather than gradually was significantly associated with sustained abstinence (prevalence ratio, 1.27 [95% CI, 1.10-1.48]). Among women who had never used NRT or SSM, most (219/275 [79.6%]) reported reasons for this in the category of attitudes and beliefs. NRT and SSM use was also more likely among women who were confident talking to their doctor about quitting (odds ratio, 2.50 [95% CI, 1.23-5.10]) and those who received most of their information from a health professional (odds ratio, 1.71 [95% CI, 1.11-2.63]).

CONCLUSION

Aboriginal and Torres Strait Islander women want to quit smoking and are making attempts to quit. Quitting suddenly, rather than reducing cigarette consumption, is associated with increased sustained abstinence. Health providers can enable access and uptake of NRT and/or SSM and should recognise that NRT and/or SSM use may change over time. Consistent messaging, frequent offers of smoking cessation support, and access to a range of smoking cessation supports should be provided to Aboriginal and Torres Strait Islander women to enable them to be smoke-free.

Modelling the Tumor Microenvironment: Recapitulating Nano- and Micro-Scale Properties that Regulate Tumor Progression

Breast cancer remains a significant burden with 1 in 8 women affected and metastasis posing a significant challenge for patient survival. Disease progression involves remodeling of the extracellular matrix (ECM). In breast cancer, tissue stiffness increases owing to an increase in collagen production by recruited cancer-associated fibroblasts (CAFs). These stromal modifications are notable during primary tumor growth and have a dualistic action by creating a hard capsule to prevent penetration of anti-cancer therapies and forming a favorable environment for tumor progression. Remodeling of the tumor microenvironment immediately presented to cells can include changes in protein composition, concentration and structural arrangement and provides the first mechanical stimuli in the metastatic cascade. Not surprisingly, metastatic cancer cells possess the ability to mechanically adapt, and their adaptability ensures not only survival but successful invasion within altered environments. In the past decade, the importance of the microenvironment and its regulatory role in diseases have gained traction and this is evident in the shift from plastic culture to the development of novel biomaterials that mimic in vivo tissue. With these advances, elucidations can be made into how ECM remodeling and more specifically, altered cell-ECM adhesions, regulate tumor growth and cancer cell plasticity. Such enabling tools in mechanobiology will identify fundamental mechanisms in cancer progression that eventually help develop preventative and therapeutic treatment from a clinical perspective. This review will focus on current platforms engineered to mimic the micro and nano-properties of the tumor microenvironment and subsequent understanding of mechanically regulated pathways in cancer.

Circulating Cystatin C Is an Independent Risk Marker for Cardiovascular Outcomes, Development of Renal Impairment, and Long-Term Mortality in Patients With Stable Coronary Heart Disease: The LIPID Study

Background

Elevated plasma cystatin C levels reflect reduced renal function and increased cardiovascular risk. Less is known about whether the increased risk persists long‐term or is independent of renal function and other important biomarkers.

Methods and Results

Cystatin C and other biomarkers were measured at baseline (in 7863 patients) and 1 year later (in 6106 patients) in participants in the LIPID (Long‐Term Intervention with Pravastatin in Ischemic Disease) study, who had a previous acute coronary syndrome. Outcomes were ascertained during the study (median follow‐up, 6 years) and long‐term (median follow‐up, 16 years). Glomerular filtration rate (GFR) was estimated using Chronic Kidney Disease Epidemiology Collaboration equations (first GFR‐creatinine, then GFR‐creatinine‐cystatin C). Over 6 years, in fully adjusted multivariable time‐to‐event models, with respect to the primary end point of coronary heart disease mortality or nonfatal myocardial infarction, for comparison of Quartile 4 versus 1 of baseline cystatin C, the hazard ratio was 1.37 (95% CI, 1.07–1.74; P=0.01), and for major cardiovascular events was 1.47 (95% CI, 1.19–1.82; P<0.001). Over 16 years, the association of baseline cystatin C with coronary heart disease, cardiovascular, and all‐cause mortality persisted (each P<0.001) and remained significant after adjustment for estimated GFR‐creatinine‐cystatin C. Cystatin C also predicted the development of chronic kidney disease for 6 years (odds ratio, 6.61; 95% CI, 4.28–10.20) independently of estimated GFR‐creatinine and other risk factors. However, this association was no longer significant after adjustment for estimated GFR‐creatinine‐cystatin C.

Conclusions

Cystatin C independently predicted major cardiovascular events, development of chronic kidney disease, and cardiovascular and all‐cause mortality. Prediction of long‐term mortality was independent of improved estimation of GFR.

Registration

URL: https://anzctr.org.au; Unique identifier: ACTRN12616000535471.

Sympatho-adrenergic mechanisms in heart failure: new insights into pathophysiology

The sympathetic nervous system is activated in the setting of heart failure (HF) to compensate for hemodynamic instability. However, acute sympathetic surge or sustained high neuronal firing rates activates β-adrenergic receptor (βAR) signaling contributing to myocardial remodeling, dysfunction and electrical instability. Thus, sympatho-βAR activation is regarded as a hallmark of HF and forms pathophysiological basis for β-blocking therapy. Building upon earlier research findings, studies conducted in the recent decades have significantly advanced our understanding on the sympatho-adrenergic mechanism in HF, which forms the focus of this article. This review notes recent research progress regarding the roles of cardiac β2AR or α1AR in the failing heart, significance of β1AR-autoantibodies, and βAR signaling through G-protein independent signaling pathways. Sympatho-βAR regulation of immune cells or fibroblasts is specifically discussed. On the neuronal aspects, knowledge is assembled on the remodeling of sympathetic nerves of the failing heart, regulation by presynaptic α2AR of NE release, and findings on device-based neuromodulation of the sympathetic nervous system. The review ends with highlighting areas where significant knowledge gaps exist but hold promise for new breakthroughs.

Effects of acetazolamide on control of breathing in sleep apnea patients: Mechanistic insights using meta-analyses and physiological model simulations

Obstructive and central sleep apnea affects ~1 billion people globally and may lead to serious cardiovascular and neurocognitive consequences, but treatment options are limited. High loop gain (ventilatory instability) is a major pathophysiological mechanism underlying both types of sleep apnea and can be lowered pharmacologically with acetazolamide, thereby improving sleep apnea severity. However, individual responses vary and are strongly correlated with the loop gain reduction achieved by acetazolamide. To aid with patient selection for long-term trials and clinical care, our goal was to understand better the factors that determine the change in loop gain following acetazolamide in human subjects with sleep apnea. Thus, we (i) performed several meta-analyses to clarify how acetazolamide affects ventilatory control and loop gain (including its primary components controller/plant gain), and based on these results, we (ii) performed physiological model simulations to assess how different baseline conditions affect the change in loop gain. Our results suggest that (i) acetazolamide primarily causes a left shift of the chemosensitivity line thus lowering plant gain without substantially affecting controller gain; and (ii) higher controller gain, higher paCO2 at eupneic ventilation, and lower CO2 production at baseline result in a more pronounced loop gain reduction with acetazolamide. In summary, the combination of mechanistic meta-analyses with model simulations provides a unified framework of acetazolamide's effects on ventilatory control and revealed physiological predictors of response, which are consistent with empirical observations of acetazolamide's effects in different sleep apnea subgroups. Prospective studies are needed to validate these predictors and assess their value for patient selection.

Spatial concentration and distribution of phase singularities in human atrial fibrillation: Insights for the AF mechanism

BACKGROUND

Atrial fibrillation (AF) is characterized by the repetitive regeneration of unstable rotational events, the pivot of which are known as phase singularities (PSs). The spatial concentration and distribution of PSs have not been systematically investigated using quantitative statistical approaches.

OBJECTIVES

We utilized a geospatial statistical approach to determine the presence of local spatial concentration and global clustering of PSs in biatrial human AF recordings.

METHODS

64-electrode conventional basket (~5 min, n = 18 patients, persistent AF) recordings were studied. Phase maps were produced using a Hilbert-transform based approach. PSs were characterized spatially using the following approaches: (i) local "hotspots" of high phase singularity (PS) concentration using Getis-Ord Gi* (Z ≥ 1.96, P ≤ .05) and (ii) global spatial clustering using Moran's I (inverse distance matrix).

RESULTS

Episodes of AF were analyzed from basket catheter recordings (H: 41 epochs, 120 000 s, n = 18 patients). The Getis-Ord Gi* statistic showed local PS hotspots in 12/41 basket recordings. As a metric of spatial clustering, Moran's I showed an overall mean of 0.033 (95% CI: 0.0003-0.065), consistent with the notion of complete spatial randomness.

CONCLUSION

Using a systematic, quantitative geospatial statistical approach, evidence for the existence of spatial concentrations ("hotspots") of PSs were detectable in human AF, along with evidence of spatial clustering. Geospatial statistical approaches offer a new approach to map and ablate PS clusters using substrate-based approaches.