Blood Pressure Lowering in Patients With Central Hypertension: A randomized Clinical Trial

BACKGROUND

Cuff blood pressure (BP) is recommended for guiding hypertension management. However, central BP has been proposed as a superior clinical measurement. This study aimed to determine whether controlling hypertension as measured by central BP was beneficial in reducing left ventricular mass index beyond control of standard cuff hypertension.

METHODS

This multicenter, open-label, blinded-end point trial was conducted in individuals treated for uncomplicated hypertension with controlled cuff BP (<140/90 mm Hg) but elevated central BP (≥0.5 SD above age- and sex-specific normal values). Participants were randomized to 24-months intervention with spironolactone 25 mg/day (n=148) or usual care control (n=153). The primary outcome was change in left ventricular mass index measured by cardiac MRI. Cuff and central BPs were measured by clinic, 7-day home and 24-hour ambulatory BPs.

RESULTS

At 24-months, there was a greater reduction in left ventricular mass index (-3.2 [95% CI, -5.0 to -1.3] g/m2; P=0.001) with intervention compared with control. Cuff and central BPs were lowered by a similar magnitude across all BP measurement modes (eg, clinic cuff systolic BP, -6.16 [-9.60 to -2.72] mm Hg and clinic central systolic BP, -4.96 [-8.06 to -1.86] mm Hg; P≥0.48 all). Secondary analyses found that changes in left ventricular mass index correlated to changes in BP, with the magnitude of effect nearly identical for BP measured by cuff (eg, 24-hour systolic BP, β, 0.17 [0.02-0.31] g/m2) or centrally (24-hour systolic BP, β, 0.16 [0.01-0.32] g/m2).

CONCLUSIONS

Among individuals with central hypertension, spironolactone had beneficial effects in reducing LV mass. Secondary analyses showed that changes in LV mass were equally well associated with lower measured standard cuff BP and central BP.

REGISTRATION

URL: https://www.anzctr.org.au/; Unique identifier: ACTRN12613000053729.

Participant characteristics and reasons for non-consent to health information linkage for research: experiences from the ATHENA COVID-19 study

BACKGROUND

The linkage of primary care, hospital and other health registry data is a global goal, and a consent-based approach is often used. Understanding the attitudes of why participants take part is important, yet little is known about reasons for non-participation. The ATHENA COVID-19 feasibility study investigated: 1) health outcomes of people diagnosed with COVID-19 in Queensland, Australia through primary care health data linkage using consent, and 2) created a cohort of patients willing to be re-contacted in future to participate in clinical trials. This report describes the characteristics of participants declining to participate and reasons for non-consent.

METHODS

Patients diagnosed with COVID-19 from January 1st, 2020, to December 31st, 2020, were invited to consent to having their primary healthcare data extracted from their GP into a Queensland Health database and linked to other data sets for ethically approved research. Patients were also asked to consent to future recontact for participation in clinical trials. Outcome measures were proportions of patients consenting to data extraction, permission to recontact, and reason for consent decline.

RESULTS

Nine hundred and ninety-five participants were approached and 842(85%) reached a consent decision. 581(69%), 615(73%) and 629(75%) consented to data extraction, recontact, or both, respectively. Mean (range) age of consenters and non-consenters were 50.6(22-77) and 46.1(22-77) years, respectively. Adjusting for age, gender and remoteness, older participants were more likely to consent than younger (aOR 1.02, 95%CI 1.01 to 1.03). The least socio-economically disadvantaged were more likely to consent than the most disadvantaged (aOR 2.20, 95% 1.33 to 3.64). There was no difference in consent proportions regarding gender or living in more remote regions. The main reasons for non-consent were 'not interested in research' (37%), 'concerns about privacy' (15%), 'not registered with a GP' (8%) and 'too busy/no time' (7%). 'No reason' was given in 20%.

CONCLUSION

Younger participants and the more socio-economically deprived are more likely to non-consent to primary care data linkage. Lack of patient interest in research, time required to participate and privacy concerns, were the most common reasons cited for non-consent. Future health care data linkage studies addressing these issues may prove helpful.

Emerging challenges of the impacts of pharmaceuticals on aquatic ecosystems: A diatom perspective

Pharmaceuticals are a ubiquitous group of emerging pollutants of considerable importance due to their biological potency and potential to elicit effects in wildlife and humans. Pharmaceuticals have been quantified in terrestrial, marine, fresh, and transitional waters, as well as the fauna and macro-flora that inhabit them. Pharmaceuticals can enter water ways through different human and veterinary pathways with traditional wastewater treatment, unable to completely remove pharmaceuticals, discharging often unknown quantities to aquatic ecosystems. However, there is a paucity of available information regarding the effects of pharmaceuticals on species at the base of aquatic food webs, especially on phytoplankton, with research typically focussing on fish and aquatic invertebrates. Diatoms are one of the main classes of phytoplankton and are some of the most abundant and important organisms in aquatic systems. As primary producers, diatoms generate ∼40 % of the world's oxygen and are a vital food source for primary consumers. Diatoms can also be used for bioremediation of polluted water bodies but perhaps are best known as bio-indicators for water quality studies. However, this keystone, non-target group is often ignored during ecotoxicological studies to assess the effects of pollutants of concern. Observed effects of pharmaceuticals on diatoms have the potential to be used as an indicator of pharmaceutical-induced impacts on higher trophic level organisms and wider ecosystem effects. The aim of this review is to present a synthesis of research on pharmaceutical exposure to diatoms, considering ecotoxicity, bioremediation and the role of diatoms as bio-indicators. We highlight significant omissions and knowledge gaps which need addressing to realise the potential role of diatoms in future risk assessment approaches and help evaluate the impacts of pharmaceuticals in the aquatic environment at local and global scales.

The cost-effectiveness of coronary calcium score-guided statin therapy initiation for Australians with family histories of premature coronary artery disease

OBJECTIVES

To compare the cost-effectiveness of coronary artery calcium (CAC) score-guided statin therapy criteria and American College of Cardiology/American Heart Association (ACC/AHA) guidelines (10-year pooled cohort equation [PCE] risk ≥ 7.5%) with selection according to Australian guidelines (5-year absolute cardiovascular disease risk [ACVDR] ≥ 10%), for people with family histories of premature coronary artery disease.

STUDY DESIGN, SETTING

Markov microsimulation state transition model based on data from the Coronary Artery calcium score: Use to Guide management of Hereditary Coronary Artery Disease (CAUGHT-CAD) trial and transition probabilities derived from published statin prescribing and adherence outcomes and clinical data.

PARTICIPANTS

1083 people with family histories of premature coronary artery disease but no symptomatic cardiovascular disease.

MAIN OUTCOME MEASURES

Relative cost-effectiveness over fifteen years, from the perspective of the Australian health care system, compared with usual care (Australian guidelines), assessed as incremental cost-effectiveness ratios (ICERs), with a notional willingness-to-pay threshold of $50 000 per quality-adjusted life-year (QALY) gained.

RESULTS

Applying the Australian guidelines, 77 people were eligible for statin therapy (7.1%); with ACVDR 5-year risk ≥ 2% and CAC score > 0, 496 people (46%); with ACVDR 5-year risk ≥ 2% and CAC score ≥ 100, 155 people (14%); and with the ACC/AHA guidelines, 256 people (24%). The ICERs for CAC-guided selection were $33 108 (CAC ≥ 100) and $53 028 per QALY gained (CAC > 0); the ACC/AHA guidelines approach (ICER, $909 241 per QALY gained) was not cost-effective. CAC score-guided selection (CAC ≥ 100) was cost-effective for people with 5-year ACVDR of at least 5%.

CONCLUSION

Expanding the number of people at low to intermediate CVD risk eligible for statin therapy should selectively target people with subclinical atherosclerosis identified by CAC screening. This approach can be more cost-effective than simply lowering treatment eligibility thresholds.

Evaluating the magnet response in deep subcutaneous implanted cardioverter defibrillator implants

INTRODUCTION

The manufacturer of subcutaneous implantable cardioverter defibrillators (S-ICDs) acknowledges that 'deep implants' may fail to elicit a magnet response, however, does not define 'deep implant' or recommend a maximum implant depth. This study aims to systematically evaluate the effect of subcutaneous tissue depth and magnet types on evoked magnet response.

METHODS

Sunshine Coast University Hospital's S-ICD cohort underwent magnet response evaluation; where bar and donut magnets were compared and the evoked magnet response was recorded in three separate zones, guided by a template. Ordinal regression (OR) models assessed the relationship between the evoked magnet response and tissue depth (TD), measured via post-implant X-Ray. The patient's ability to hear the magnet response audible tone was recorded.

RESULTS

Patients (n = 39) with measurable TD (n = 30) were analyzed. The bar magnet evoked a magnet response in all zones in 53% of patients, compared with 73% of patients with the donut magnet (p = 0.18). The relationship between bar magnet response and TD showed the odds of an evoked magnet response decreased by 11% every 1 mm increase in TD (OR of 0.89, p < 0.01), whereas the donut magnet decreased by 16% per 1 mm (OR of 0.84, p < 0.01). Directly over the S-ICD was the most effective in evoking magnet response with the bar (85% of patients), and off-centre was most effective for the donut magnet (100%). BMI and Praetorian score were not significantly associated with magnet response. We found 23% of patients were unable to detect the audible tone.

CONCLUSION

We observed a statistically significant association between TD and ability to evoke magnet response. The bar magnet was less reliable than the donut magnet for therapy inhibition in deep implants.

Type-2 Diabetes and the Clinical Importance of Exaggerated Exercise Blood Pressure

BACKGROUND

Exaggerated exercise blood pressure (EEBP) during clinical exercise testing is associated with poor blood pressure (BP) control and cardiovascular disease (CVD). Type-2 diabetes (T2DM) is thought to be associated with increased prevalence of EEBP, but this has never been definitively determined and was the aim of this study.

METHODS

Clinical exercise test records were analyzed from 13 268 people (aged 53±13 years, 59% male) who completed the Bruce treadmill protocol (stages 1-4, and peak) at 4 Australian public hospitals. Records (including BP) were linked to administrative health datasets (hospital and emergency admissions) to define clinical characteristics and classify T2DM (n=1199) versus no T2DM (n=12 069). EEBP was defined as systolic BP ≥90th percentile at each test stage. Exercise BP was regressed on T2DM history and adjusted for CVD and risk factors.

RESULTS

Prevalence of EEBP (age, sex, preexercise BP, hypertension history, CVD history and aerobic capacity adjusted) was 12% to 51% greater in T2DM versus no T2DM (prevalence ratio [95% CI], stage 1, 1.12 [1.02-1.24]; stage 2, 1.51 [1.41-1.61]; stage 3, 1.25 [1.10-1.42]; peak, 1.18 [1.09-1.29]). At stages 1 to 3, 8.6% to 15.8% (4.8%-9.7% T2DM versus 3.5% to 6.1% no-T2DM) of people with 'normal' preexercise BP (<140/90 mm Hg) were identified with EEBP. Exercise systolic BP relative to aerobic capacity (stages 1-4 and peak) was higher in T2DM with adjustment for all CVD risk factors.

CONCLUSIONS

People with T2DM have higher prevalence of EEBP and exercise systolic BP independent of CVD and many of its known risk factors. Clinicians supervising exercise testing should be alerted to increased likelihood of EEBP and thus poor BP control warranting follow-up care in people with T2DM.

Myocarditis and Cardiac Complications Associated With COVID-19 and mRNA Vaccination: A Pragmatic Narrative Review to Guide Clinical Practice

Coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus is likely to remain endemic globally despite widespread vaccination. There is increasing concern for myocardial involvement and ensuing cardiac complications due to COVID-19, however, the available evidence suggests these risks are low. Pandemic publishing has resulted in rapid manuscript availability though pre-print servers. Subsequent article retractions, a lack of standardised definitions, over-reliance on isolated troponin elevation and the heterogeneity of studied patient groups (i.e. severe vs. symptomatic vs all infections) resulted in early concern for high rates of myocarditis in patients with and recovering from COVID-19. The estimated incidence of myocarditis in COVID-19 infection is 11 cases per 100,000 infections compared with an estimated 2.7 cases per 100,000 persons following mRNA vaccination. For substantiated cases, the clinical course of myocarditis related to COVID-19 or mRNA vaccination appears mild and self-limiting, with reports of severe/fulminant myocarditis being rare. There is limited data available on the management of myocarditis in these settings.

Clinical guidance for appropriate use of cardiac investigations and monitoring in COVID-19 is needed for effective risk stratification and efficient use of cardiac resources in Australia. An amalgamation of national and international position statements and guidelines is helpful for guiding clinical practice. This paper reviews the current available evidence and guidelines and provides a summary of the risks and potential use of cardiac investigations and monitoring for patients with COVID-19.

Role of interatrial conduction in atrial fibrillation. Mechanistic insights from renewal theory-based fibrillatory dynamic analysis

Background

Interatrial conduction has been postulated to play an important role in atrial fibrillation (AF). The pathways involved in interatrial conduction during AF remain incompletely defined.

Objective

We recently showed physiological assessment of fibrillatory dynamics could be performed using renewal theory, which determines rates of phase singularity formation (λ_f) and destruction (λ_d). Using the renewal approach, we aimed to understand the role of the interatrial septum and other electrically coupled regions during AF.

Method

RENEWAL-AF is a prospective multicenter observational study recruiting AF ablation patients (ACTRN 12619001172190). We studied unipolar electrograms obtained from 16 biatrial locations prior to ablation using a 16-electrode Advisor HD Grid catheter. Renewal rate constants λ_f and λ_d were calculated, and the relationships between these rate constants in regions of interatrial connectivity were examined.

Results

Forty-one AF patients (28.5% female) were recruited. A positive linear correlation was observed between λ_f and λ_d (1) across the interatrial septum (λ_f r² = 0.5, P < .001, λ_d r² = 0.45, P < .001), (2) in regions connected by the Bachmann bundle (right atrial appendage–left atrial appendage λ_f r² = 0.29, P = .001; λ_d r² = 0.2, P = .008), and (3) across the inferior interatrial routes (cavotricuspid isthmus–left atrial septum λ_f r² = 0.67, P < .001; λ_d r² = 0.55, P < .001). Persistent AF status and left atrial volume were found to be important effect modifiers of the degree of interatrial renewal rate statistical correlation.

Conclusion

Our findings support the role of interseptal statistically determined electrical disrelation in sustaining AF. Additionally, renewal theory identified preferential conduction through specific interatrial pathways during fibrillation. These findings may be of importance in identifying clinically significant targets for ablation in AF patients.

Effect of a 3-Year Lifestyle Intervention in Patients with Chronic Kidney Disease: A Randomized Clinical Trial

BACKGROUND

Supervised lifestyle interventions have the potential to significantly improve physical activity and fitness in patients with CKD.

METHODS

To assess the efficacy of a lifestyle intervention in patients with CKD to improve cardiorespiratory fitness and exercise capacity over 36 months, we conducted a randomized clinical trial, enrolling 160 patients with stage 3-4 CKD, with 81 randomized to usual care and 79 to a 3-year lifestyle intervention. The lifestyle intervention comprised care from a multidisciplinary team, including a nephrologist, nurse practitioner, exercise physiologist, dietitian, diabetes educator, psychologist, and social worker. The exercise training component consisted of an 8-week individualized and supervised gym-based exercise intervention followed by 34 months of a predominantly home-based program. Self-reported physical activity (metabolic equivalent of tasks [METs] minutes per week), cardiorespiratory fitness (peak O₂ consumption [VO_2peak]), exercise capacity (maximum METs and 6-minute walk distance) and neuromuscular fitness (grip strength and get-up-and-go test time) were evaluated at 12, 24, and 36 months.

RESULTS

The intervention increased the percentage of patients meeting physical activity guideline targets of 500 MET min/wk from 29% at baseline to 63% at 3 years. At 12 months, both VO_2peak and METs increased significantly in the lifestyle intervention group by 9.7% and 30%, respectively, without change in the usual care group. Thereafter, VO_2peak declined to near baseline levels, whereas METs remained elevated in the lifestyle intervention group at 24 and 36 months. After 3 years, the intervention had increased the 6-minute walk distance and blunted declines in the get-up-and-go test time.

CONCLUSIONS

A 3-year lifestyle intervention doubled the percentage of CKD patients meeting physical activity guidelines, improved exercise capacity, and ameliorated losses in neuromuscular and cardiorespiratory fitness.

Diet Quality and Protein-Bound Uraemic Toxins: Investigation of Novel Risk Factors and the Role of Microbiome in Chronic Kidney Disease

OBJECTIVE

This study aims to explore the associations between diet quality, uraemic toxins, and gastrointestinal microbiota in the chronic kidney disease (CKD) population.

METHODS

This is a baseline cross-sectional study of adults with CKD participating in a randomized controlled trial of prebiotic and probiotic supplementation. Dietary intake was measured using a seven-day diet history method, administered by a specialist dietitian. Diet quality was assessed using plant-based diet index (PDI) (overall PDI, healthy PDI, and unhealthy PDI), food group analysis, protein intake, fiber intake, and dietary protein-to-fiber ratio. Serum uraemic toxins (free and total; indoxyl sulfate and p-cresyl sulfate) were determined by ultraperformance liquid chromatography. Gastrointestinal microbiota richness, diversity, composition, and functional capacity were analyzed via metagenomic sequencing.

RESULTS

Sixty-eight adults [median age: 70 (interquartile range: 58-75) years, 66% male] with an estimated glomerular filtration rate of 34 ± 11 mL/min/1.73 m² were included, with 40 participants completing the optional fecal substudy. Dietary fiber intake was associated with lower levels of total indoxyl sulfate, whereas the healthy plant-based diet index was associated with lower levels of free p-cresyl sulfate. A higher protein-to-fiber ratio was associated with an increased relative abundance of unclassified members of order Oscillospirales. Intake of vegetables and whole grains was correlated with Subdoligranulum formicile, whereas an unclassified Prevotella species was correlated with potatoes and food items considered discretionary, including sweet drinks, sweet desserts, and animal fats.

CONCLUSIONS

Diet quality may influence uraemic toxin generation and gut microbiota diversity, composition, and function in adults with CKD. Well-designed dietary intervention studies targeting the production of uraemic toxins and exploring the impact on gut microbiome are warranted in the CKD population.

The ATHENA COVID-19 Study: Cohort profile and first findings for people diagnosed with COVID-19 in Queensland, 1 January to 31 December 2020

Background

To date, there are limited Australian data on characteristics of people diagnosed with COVID-19 and on how these characteristics relate to outcomes. The ATHENA COVID-19 Study was established to describe health outcomes and investigate predictors of outcomes for all people diagnosed with COVID-19 in Queensland by linking COVID-19 notification, hospital, general practice and death registry data. This paper reports on the establishment and first findings for the ATHENA COVID-19 Study.

Methods

Part 1 of the ATHENA COVID-19 Study used Notifiable Conditions System data from 1 January 2020 to 31 December 2020, linked to: Emergency Department Collection data for the same period; Queensland Health Admitted Patient Data Collections (from 1 January 2010 to 30 January 2021); and Deaths Registrations data (from 1 January 2020 to 17 January 2021).

Results

To 31 December 2020, a total of 1,254 people had been diagnosed with SARS-CoV-2 infection in Queensland: half were female (49.8%); two-thirds (67.7%) were aged 20-59 years; and there was an over-representation of people living in less-disadvantaged areas. More than half of people diagnosed (57.6%) presented to an ED; 21.2% were admitted to hospital as an inpatient (median length of stay 11 days); 1.4% were admitted to an intensive care unit (82.4% of these required ventilation); and there were six deaths. Analysis of factors associated with these outcomes was limited due to small case numbers: people living in less-disadvantaged areas had a lower risk of being admitted to hospital (test for trend, p < 0.001), while those living in more remote areas were less likely than people living in major cities to present to an ED (test for trend: p=0.007), which may reflect differential health care access rather than health outcomes per se. Increasing age (test for trend, p < 0.001) and being a current/recent smoker (age-sex-adjusted relative risk: 1.61; 95% confidence interval: 1.00, 2.61) were associated with a higher risk of being admitted to hospital.

Conclusion

Despite uncertainty in our estimates due to small numbers, our findings are consistent with what is known about COVID-19. Our findings reinforce the value of linking multiple data sources to enhance reporting of outcomes for people diagnosed with COVID-19 and provide a platform for longer term follow-up.

Impact of COVID-19 Pandemic on Cardiovascular Testing in Asia

Background

The coronavirus disease-2019 (COVID-19) pandemic significantly affected management of cardiovascular disease around the world. The effect of the pandemic on volume of cardiovascular diagnostic procedures is not known.

Objectives

This study sought to evaluate the effects of the early phase of the COVID-19 pandemic on cardiovascular diagnostic procedures and safety practices in Asia.

Methods

The International Atomic Energy Agency conducted a worldwide survey to assess changes in cardiovascular procedure volume and safety practices caused by COVID-19. Testing volumes were reported for March 2020 and April 2020 and were compared to those from March 2019. Data from 180 centers across 33 Asian countries were grouped into 4 subregions for comparison.

Results

Procedure volumes decreased by 47% from March 2019 to March 2020, showing recovery from March 2020 to April 2020 in Eastern Asia, particularly in China. The majority of centers cancelled outpatient activities and increased time per study. Practice changes included implementing physical distancing and restricting visitors. Although COVID testing was not commonly performed, it was conducted in one-third of facilities in Eastern Asia. The most severe reductions in procedure volumes were observed in lower-income countries, where volumes decreased 81% from March 2019 to April 2020.

Conclusions

The COVID-19 pandemic in Asia caused significant reductions in cardiovascular diagnostic procedures, particularly in low-income countries. Further studies on effects of COVID-19 on cardiovascular outcomes and changes in care delivery are warranted.

The Association Between Contrast-Enhanced Ultrasound and Near-Infrared Spectroscopy-Derived Measures of Calf Muscle Microvascular Responsiveness in Older Adults

BACKGROUND AND AIM

Contrast-enhanced ultrasound (CEUS) measures of post-occlusion skeletal muscle microvascular responsiveness demonstrate the microvascular dysfunction associated with ageing and age-related disease. However, the accessibility of CEUS is limited by the need for intravenous administration of ultrasound contrast agents and sophisticated imaging analysis. Alternative methods are required for the broader assessment of microvascular dysfunction in research and clinical settings. Therefore, we aimed to evaluate the level of association and agreement between CEUS and near-infrared spectroscopy (NIRS)-derived measures of post-occlusion skeletal muscle microvascular responsiveness in older adults.

METHODS

During supine rest, participants (n=15, 67±11 years) underwent 5 minutes of thigh cuff-occlusion (200 mmHg). Post-occlusion CEUS measures of calf muscle microvascular responsiveness were made, including time to 95% peak acoustic intensity (TTP⁹⁵ AI) and the rate of rise (slope AI). Simultaneous measures, including time to 95% peak oxygenated haemoglobin (TTP⁹⁵ O₂Hb) and slope O₂Hb, were made using continuous-wave NIRS in the same muscle region.

RESULTS

There were strong correlations between TTP⁹⁵ measures derived from CEUS and NIRS (r=0.834, p=<0.001) and the corresponding measures of slope (r=0.735, p=0.004). The limits of agreement demonstrated by Bland Altman plot analyses for CEUS and NIRS-derived measures of TTP⁹⁵ (-9.67-1.98 s) and slope (-1.29-5.23%. s^-1) were smaller than the minimum differences expected in people with microvascular dysfunction.

CONCLUSIONS

The strong correlations and level of agreement in the present study support the use of NIRS as a non-invasive, portable and cost-effective method for assessing post-occlusion skeletal muscle microvascular responsiveness in older adults.

MO590GUT HEALTH INTERVENTIONS IN CHRONIC KIDNEY DISEASE: ACCEPTABILITY AND FEASIBILITY OF OF SYNBIOTIC SUPPLEMENTATION

Background and Aims

Synbiotics, co-administered prebiotics and probiotics, have emerged over the last decade as an innocuous intervention targeting the microbial generation of the uraemic toxins, indoxyl sulphate (IS) and p-cresyl sulphate (PCS). However, most trials to date are of short duration (2-24 weeks). In order to inform translation into clinical practice, it is imperative to consider the efficacy of synbiotic supplementation as a long-term intervention. The aims of this study were to evaluate the feasibility and acceptability (including symptoms and adherence) of long-term synbiotic supplementation in adults with chronic kidney disease (CKD), as well as explore the perspectives of these patients on nutrition supplementation for gut health, including strategies to optimise adherence in practice.

Method

SYNERGY II was a double-blind randomised controlled trial in adults (&gt;18years) with stage 3-4 CKD over 12 months. The intervention comprised of daily prebiotic powder (2 x 10g/day resistant starch) and probiotic supplementation (single sachet of 6g/day multi strain 4.5x1011CFU) or placebo control (waxy maize powder and a sachet of maltodextrin). Adherence to nutrition supplementation was defined as participants consuming &gt;80% of the prescribed sachets/powder. Symptoms were monitored via Gastrointestinal Symptom Rating Scale (GSRS) and Bristol Stool Score (BSS). Semi-structured interviews were conducted in person or by telephone with a sample of 30 participants at the completion of the intervention. The interviews explored experiences and perspectives regarding frequencies, timing and difficulties experienced with each aspect of the intervention and overall perceptions of the intervention as a strategy to improve gut health.

Results

Sixty-eight participants [66% male, median age 70 (IQR 58-75) years] were consented and randomised to either intervention or control groups, with a mean estimated glomerular filtration rate of 34 ± 11 mL/min/1.73m2. A total of 56 participants (82%) completed the 12-month intervention with no differences in withdrawals between groups (p=0.6). One participant from each group withdrew at week 2, citing palatability of the study product as the reason for withdrawal. Overall adherence to study supplementation was excellent in both intervention and placebo groups [median intake 92.1% (85.9-95.2%) placebo versus 89.5% (84.4-94.5%) synbiotic; P=0.4)]. Overall, there was no significant change from baseline to end of study visit for mean BSS (3.6 ± 1.4 to 3.6 ± 1.4 placebo versus 3.6 ± 1.1 to 4.1 ± 1.2 synbiotic, P=0.13), mean bowel movements (1.3 ± 0.6 to 1.6 ± 0.9 placebo versus 1.3 ± 0.6 to 1.8 ± 1.0 synbiotic, P=0.70) or GSRS [1.3 (1.1 - 1.9) to 1.3 (1.1 - 1.5) placebo versus 1.1 (1.1 - 1.5) to 1.3 (1.1 - 1.5) synbiotic, P=0.83]. Acceptability components described by participants were appreciating convenience and improving health and well-being. Participants discussed the following feasibility components: integrating easily into lifestyle and social accountability. Tablets or capsules were the preferred supplement formulation with a probiotic drink made from a SCOBY (synbiotic culture of bacteria and yeast) the least preferred.

Conclusion

Among adults with stage 3-4 CKD, synbiotic supplementation is a well-tolerated and acceptable form of nutrition supplementation. People with CKD would prefer nutrition supplements to be formulated as a tablet or capsule, which is an important consideration when translating into clinical practice.

FC 082DIET QUALITY, PROTEIN-BOUND URAEMIC TOXINS AND GASTROINTESTINAL MICROBIOME IN CHRONIC KIDNEY DISEASE

Background and Aims

Individuals with chronic kidney disease (CKD) have significantly increased risk of cardiovascular mortality which is only partially explained by Framingham risk factors. There is a growing body of evidence linking the gut-derived uraemic toxins indoxyl sulphate (IS) and p-cresyl sulphate (PCS) with accelerated kidney disease progression and cardiovascular burden in CKD. Whilst the effect of specific nutrients on uraemic toxin generation has been explored, few studies have characterised the impact of diet quality on the gastrointestinal microbiome in the CKD population. This study aims to explore the associations between dietary quality, protein-bound uraemic toxins and gastrointestinal microbiome in adults with CKD.

Method

This was a baseline cross-sectional study of adults with stage 3 to 4 CKD who were enrolled in a randomised controlled trial of prebiotic and probiotic supplementation. Habitual dietary intake was measured using a 7-day diet history method by a specialist Dietitian. Diet quality was assessed using food group analysis; protein intake, fibre intake, dietary protein:fibre ratio and adherence to plant-based diet index (PDI) (overall PDI, healthy PDI, unhealthy PDI). Serum uraemic toxins (free and total; IS and PCS) were determined by ultra-performance liquid chromatography. Metagenomic sequencing was used to determine gastrointestinal microbiota richness, diversity, composition and functional capacity.

Results

There were 68 CKD patients [66% male, median age 70 (IQR 58-75) years] with a mean estimated glomerular filtration rate of 34 ± 11 mL/min/1.73m2. Greater adherence to a hPDI was associated with lower levels of free PCS [-0.021 µmol/L (95% CI -0.042 to -0.001)], while a higher intake of dietary fibre intake was associated with lower levels of free IS [-0.022 µmol/L (95% CI -0.043 to -0.001)]. Compositionally, the gastrointestinal microbiota of this cohort was dominated by members of the phyla Firmicutes and Bacteroidetes. Supervised analysis at the species level demonstrated that 21% of variance in gastrointestinal microbial composition could be attributed to protein:fibre ratio (F=1.27, p=0.04). Further, a higher protein:fibre ratio was associated with an increased relative abundance of unclassified members of order Oscillospirales. Subdoligranulum formicile was correlated with dietary intake of vegetables and wholegrains while an unclassified Prevotella species was correlated with food items considered discretionary including sweet drinks, sweet desserts, animal fats and potatoes.

Conclusion

The study suggests that habitual diets that are higher in fibre and plant-based foods may positively influence uraemic toxin levels and gut microbiota diversity and composition in adults with CKD. These findings provide rationale for well-designed dietary intervention studies targeting the production of uraemic toxins and exploring the impact on gut microbiome in the CKD population.

Cognitive impairment as a determinant of response to management plans after heart failure admission

AIMS

Cognitive impairment (CI) is highly prevalent in heart failure (HF), and increases patients' risks of readmission. This study sought to determine whether the presence and degree of CI could identify patients most likely to benefit from a HF disease management programme (DMP) to reduce readmissions.

METHODS AND RESULTS

A total of 1152 consecutive Australian patients admitted with HF (2014-2017) were prospectively followed up for 12 months. Of these, 324 patients who received DMP (1-month duration, including post-discharge home visits, medication reconciliation, exercise guidance and early clinical review) were matched (1:2 ratio) with 648 usual care patients. Cognitive function was assessed either on the day of or one day before discharge using the Montreal Cognitive Assessment (MoCA). Outcomes included readmission or death at 1, 3 and 12 months, and days at home within 12 months of discharge. Poorer cognitive function was associated with all adverse outcomes. Compared with usual care, DMP was associated with lower odds of 30-day [odds ratio (OR) 0.60, 95% confidence interval 0.40, 0.91] and 90-day (OR 0.53, 95% confidence interval 0.36, 0.77) readmission or death, and with 19 more days at home within 12 months, independent of HF therapy. The effect sizes of these associations were greater for patients with diminished cognition than those with normal cognition (interaction P = 0.036), and might have been more pronounced among those with mild CI compared with those with more severe CI (MoCA score 17-22; OR 0.42, 95% confidence interval 0.21, 0.87) at 30 days (OR 0.31, 95% confidence interval 0.16, 0.60 at 90 days). Patients with normal cognition had fewer events, irrespective of DMP.

CONCLUSIONS

Cognitive function may determine how HF patients respond to a DMP. Cognitive screening before implementation of a DMP may allow personalized plans for patients with different levels of cognitive function.

Absolute cardiovascular disease risk score and pharmacotherapy at the time of admission in patients presenting with acute coronary syndrome due to coronary artery disease in a single Australian tertiary centre: a cross-sectional study

OBJECTIVES

To describe (1) absolute cardiovascular disease risk (ACVDR) scores in patients presenting to hospital with acute coronary syndrome (ACS) and (2) proportions of these patients on guideline-recommended pharmacotherapy according to their ACVDR score.

DESIGN

Cross-sectional study.

SETTING

Single-site tertiary centre hospital, Queensland, Australia over a 12-month period.

PARTICIPANTS

Patients >18 years of age presenting to hospital with ACS due to coronary artery disease (CAD) confirmed by angiography.

PRIMARY AND SECONDARY OUTCOME MEASURES

Proportion of patients without prior history of CVD with a high ACVDR score, and of patients with a prior history of CVD, who are on guideline-recommended pharmacotherapy.

RESULTS

527 ACS patients were included of whom the mean age was 63 years and 75% were male. Overall, 66% (350) had no prior CVD and 34% (177) patients had prior CVD.In patients with no prior CVD, the proportions of patients with low, intermediate and high CVD risk scores were 41%, 24% and 36%. In the no prior CVD, high-risk patient group, 48% were on no preventative pharmacotherapy, 32% on single pharmacotherapy and 20% patients on complete guideline-recommended pharmacotherapy. In the prior CVD group, 7% patients were on no pharmacotherapy, 40% on incomplete pharmacotherapy and 53% were on complete guideline-recommended pharmacotherapy.

CONCLUSION

This study adds to the evidence on implementation gaps in guideline-recommended management of ACVDR, showing that a large proportion of patients presenting with ACS due to CAD were at high risk of developing CVD prior to the event and most were not on guideline-recommended treatment. A significant proportion of these events are likely to have been preventable, and therefore, increased assessment and appropriate treatment of ACVDR in primary care is needed to reduce the incidence of CVD events in the population.

Cost-Effectiveness of Coronary Artery Calcium Scoring in People With a Family History of Coronary Disease

OBJECTIVES

To assess the cost effectiveness of coronary artery calcium (CAC) compared with traditional risk factor-based prediction alone in those with an family history of premature coronary artery disease (FHCAD).

BACKGROUND

The use of CAC scoring to guide primary prevention statin therapy in those with a FHCAD is inconsistently recommended in guidelines, and usually not reimbursed by insurance.

METHODS

A microsimulation model was constructed in TreeAge Healthcare Pro using data from 1,083 participants in the CAUGHT-CAD (Coronary Artery Calcium Score: Use to Guide Management of HerediTary Coronary Artery Disease) trial. Outcomes assessed were quality-adjusted life years (QALYs): cost-effectiveness was assessed over a 15-year time horizon from the perspective of the US health care sector using real-world statin prescribing, accounting for the effect of knowledge of subclinical disease on adherence to guideline-directed therapies. Costs were assessed in 2020 USD, with discounting undertaken at 3%.

RESULTS

Statins were indicated in 45% of the cohort using the CAC strategy and 27% using American College of Cardiology/American Heart Association (2019) treatment strategies. Compared with applying a statin treatment threshold of 7.5%, the CAC strategy was more costly ($145) and more effective (0.0097 QALY) with an incremental cost-effective ratio (ICER) of $15,014/QALY. CAC ICER was driven by CAC acquisition and statin prescription cost and improved with certain patient subgroups: male, age >60 years, and 10-year risk pooled cohort equation risk ≥7.5%. CAC scanning of low-risk patients (10-year risk <5%) or those 40 to 50 years of age was not cost-effective.

CONCLUSIONS

Systematic CAC screening and treatment of those with FHCAD and subclinical disease was more cost-effective than management using statin treatment thresholds, in the US health care system.

Cross-sectional survey describing general practitioners' absolute cardiovascular disease risk assessment practices and their relationship to knowledge, attitudes and beliefs about cardiovascular disease risk in Queensland, Australia

OBJECTIVES

To describe general practitioners' (GPs') absolute cardiovascular disease risk (ACVDR) self-reported assessment practices and their relationship to knowledge, attitudes and beliefs about ACVDR.

DESIGN

Cross-sectional survey with opportunistic sampling (October-December 2017).

SETTING

Sunshine Coast region, Queensland, Australia.

PARTICIPANTS

111 GPs responded to the survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

Proportion of GPs reporting a high (≥80%) versus moderate (60%-79%)/low (<60%) percentage of eligible patients receiving ACVDR assessment; proportion agreeing with statements pertaining to knowledge, attitudes and beliefs about ACVDR and associations between these factors.

RESULTS

Of the 111 respondents, 78% reported using the Australian ACVDR calculator; 45% reported high, 25% moderate and 30% low ACVDR assessment rates; >85% reported knowing how to use ACVDR assessment tools, believed assessment valuable and were comfortable with providing guideline-recommended treatment. Around half believed patients understood the concept of high risk and were willing to adopt recommendations. High assessment rates (vs moderate/low) were less likely among older GPs (≥45 vs ≤34 years, age-adjusted and sex-adjusted OR (aOR) 0.36, 95% CI 0.12 to 0.97). Those who answered knowledge-based questions about the guidelines incorrectly had lower assessment rates, including those who answered questions on patient eligibility (aOR 0.13, 95% CI 0.02 to 1.11). A high assessment rate was more likely among GPs who believed there was sufficient time to do the assessment (aOR 3.79, 95% CI 1.23 to 11.61) and that their patients were willing to undertake lifestyle modification (aOR 2.29, 95% CI 1.02 to 5.15). Over 75% of GPs agreed better patient education, nurse-led assessment and computer-reminder prompts would enable higher assessment rates.

CONCLUSIONS

Although the majority of GPs report using the ACVDR calculator when undertaking a CVD risk assessment, there is a need to increase the actual proportion of eligible patients undergoing ACVDR assessment. This may be achieved by improving GP assessment practices such as GP and patient knowledge of CVD risk, providing sufficient time and nurse-led assessment.

Relationship between coronary microvascular dysfunction and left ventricular diastolic function in patients with chest pain and unobstructed coronary arteries

BACKGROUD

Diastolic dysfunction (DD) is reported to affect up to 35% of the adult general population. The consequence of progressive DD is heart failure with preserved ejection fraction (HFpEF). Coronary microvascular dysfunction (CMD) has been suggested as one of the pathologic mechanisms leading to HFpEF. We investigated whether there was an association between coronary microvascular function and echocardiographic indices of left ventricular diastolic function at rest in patients with chest pain and unobstructed coronary arteries (CPUCA).

METHODS

This retrospective observational study recruited patients referred to cardiology clinics assessment of chest pain who subsequently underwent assessment via CT coronary angiogram (CTA). Coronary microvascular dysfunction was determined by myocardial blood flow reserve (MBFR; <2.0) using myocardial contrast echocardiography. Echocardiographic indices of diastolic function (septal mitral annular e'; septal mitral annular E/e', E/A ratio) were measured from baseline transthoracic echocardiogram.

RESULTS

149 patients (52% men) with a mean age 59.7(9.5) years were recruited. Mean (standard deviation) MBFR was 2.2 (0.51). 37% (55/149) had MBFR < 2.0. Median [interquartile range] septal mitral annular e' velocity and septal mitral annular E/e' were 7.6 cm/s [6.2, 8.9] and 9.5 [7.5, 10.8], respectively. Univariate regression analysis showed only age was a significant predictor of increasing septal mitral annular E/e' (β = +0.20 95% CI 0.13, +0.28, P < .001) but not MBFR. Multivariable analysis also showed no association between these septal mitral annular E/e' and MBFR after adjustment for cardiovascular risk factors.

CONCLUSION

There was no relationship found between echocardiographic indices of left ventricular diastolic function and coronary microvascular function at rest.

CSANZ Imaging Council Position Statement on Echocardiography Services During the COVID-19 Pandemic

This Cardiac Society of Australia and New Zealand (CSANZ) Imaging Council Position Statement aims to guide local, regional and national clinical practice, and facilitate resource and echocardiographic service planning appropriately during the current COVID-19 global pandemic. General considerations include workforce arrangements and contingency plans, patient risk assessment for COVID-19 and level of care (personal protective equipment) for staff. Both outpatient and inpatient settings are addressed, including specific considerations in the in-patient setting including scanning protocols, screening modalities and indications for echocardiograms in the context of COVID-19 infection.

An Experimental Series Investigating the Effects of Hyperinsulinemic Euglycemia on Myocardial Blood Flow Reserve in Healthy Individuals and on Myocardial Perfusion Defect Size following ST-Segment Elevation Myocardial Infarction

BACKGROUND

Incomplete restoration of myocardial blood flow (MBF) is reported in up to 30% of ST-segment elevation myocardial infarction (STEMI) despite prompt mechanical revascularization. Experimental hyperinsulinemic euglycemia (HE) increases MBF reserve (MBFR). If fully exploited, this effect may also improve MBF to ischemic myocardium. Using insulin-dextrose infusions to induce HE, we conducted four experiments to determine (1) how insulin infusion duration, dose, and presence of insulin resistance affect MBFR response; and (2) the effect of an insulin-dextrose infusion given immediately following revascularization of STEMI on myocardial perfusion.

METHODS

The MBFR was determined using myocardial contrast echocardiography. Experiment 1 (insulin duration): 12 participants received an insulin-dextrose or saline infusion for 120 minutes. MBFR was measured at four time intervals during infusion. Experiment 2 (insulin dose): 22 participants received one of three insulin doses (0.5, 1.5, 3.0 mU/kg/minute) for 60 minutes. Baseline and 60-minute MBFRs were determined. Experiment 3 (insulin resistance): five metabolic syndrome and six type 2 diabetes (T2DM) participants received 1.5 mU/kg/minute of insulin-dextrose for 60 minutes. Baseline and 60-minute MBFRs were determined. Experiment 4 (STEMI): following revascularization for STEMI, 20 patients were randomized to receive either 1.5 mU/kg/minute insulin-dextrose infusion for 120 minutes or standard care. Myocardial contrast echocardiography was performed at four time intervals to quantify percentage contrast defect length.

RESULTS

Experiment 1: MBFR increased with time through to 120 minutes in the insulin-dextrose group and did not change in controls. Experiment 2: compared with baseline, MBFR increased in the 1.5 (2.42 ± 0.39 to 3.25 ± 0.77, P = .002), did not change in the 0.5, and decreased in the 3.0 (2.64 ± 0.25 to 2.16 ± 0.33, P = .02) mU/kg/minute groups. Experiment 3: compared with baseline, MBFR increase was only borderline significant in metabolic syndrome and T2DM participants (1.98 ± 0.33 to 2.59 ± 0.45, P = .04, and 1.67 ± 0.35 to 2.14 ± 0.21, P = .05). Experiment 4: baseline percentage contrast defect length was similar in both groups but with insulin decreased with time and was significantly lower than in controls at 60 minutes (2.8 ± 5.7 vs 13.7 ± 10.6, P = .02).

CONCLUSIONS

Presence of T2DM, insulin infusion duration, and dose are important determinants of the MBFR response to HE. When given immediately following revascularization for STEMI, insulin-dextrose reduces perfusion defect size at one hour. Hyperinsulinemic euglycemia may improve MBF following ischemia, but further studies are needed to clarify this.

Relation of Left Atrial Volumes in Patients With Myocardial Infarction to Left Ventricular Filling Pressures and Outcomes

The inter-relationships between minimal and maximal left atrial volume index (LAVI), left ventricular filling pressures and survival have not been well studied. This study aimed to compare LAVImin with LAVImax with respect to (1) relative prognostic value, and (2) correlation with left ventricular end-diastolic pressures (LVEDP), in patients with myocardial infarction (MI). A retrospective study involving consecutive patients with a first-ever MI (n = 419) was undertaken. LAVIs were determined using Simpson's biplane method from 2D echocardiography performed the day after admission. LAVmin ≥ 18 mls/m² and LAVImax ≥ 34 mls/m² were considered enlarged. The primary end point was composite major adverse cardiovascular events (MACE) (death/MI/heart failure). Correlation between LVEDP and LAVI was assessed in 120 patients who underwent echocardiography and cardiac catheterization either simultaneously (n = 30) or same-day (n = 90). At a median follow-up of 24 months, there were 61 MACE events. On Cox proportional hazards multivariate analysis incorporating significant clinical predictors and LVEF, whereas both LAVImin ≥ 18 mls/m² (hazard ratio 3.15 [95% confidence interval 1.70 to 5.54], p <0.001) and LAVImax ≥ 34 mls/m² (hazard ratio 1.79 [95% confidence interval 1.02 to 3.14], p = 0.041) were independent predictors of MACE, LAVImin showed a stronger association. Intermodel comparisons of the model chi-square and Harrell's C-statistic confirmed better prognostication with LAVImin. In the invasive cohort, because LAVImin and LAVImax had a similar correlation with LVEDP ≥ 15 mm Hg (r = 0.41 [p <0.001] vs r = 0.42 [p <0.001]), LAVmin ≥ 18 mls/m² had a greater sensitivity for LVEDP ≥ 15 mm Hg than LAVImax ≥ 34 mls/m² (sensitivity 59.4% vs 34.4%). In conclusion, utilizing thresholds of ≥18 and ≥34 mls/m², respectively, LAVImin was a better predictor of survival than LAVImax, the pathophysiologic basis of which relates to a better sensitivity for elevated left ventricular filling pressures with LAVImin at these thresholds. There may be incremental clinical value in measuring LAVImin alongside LAVImax.

The Clinical Utility and Enduring Versatility of Stress Echocardiography

Stress echocardiography is an established cardiac imaging modality for the detection and quantification of severity of coronary artery disease. In recent years, there has also been an increasing use of stress echocardiography in the assessment of non-ischaemic cardiac disease given its ability to assess functional capacity and haemodynamic changes with exercise which can help guide therapy and inform prognosis. The emerging use of strain, myocardial contrast and three-dimensional (3D) echocardiography further assists in improving diagnostic accuracy particularly in patients with coronary artery disease. This paper summarises the protocols, indications and clinical applications of stress echocardiography in both ischaemic and non-ischaemic cardiac disease.

Validation of Predictive Score of 30-Day Hospital Readmission or Death in Patients With Heart Failure

Existing prediction algorithms for the identification of patients with heart failure (HF) at high risk of readmission or death after hospital discharge are only modestly effective. We sought to validate a recently developed predictive model of 30-day readmission or death in HF using an Australia-wide sample of patients. This study used data from 1,046 patients with HF at teaching hospitals in 5 Australian capital cities to validate a predictive model of 30-day readmission or death in HF. Besides standard clinical and administrative data, we collected data on individual sociodemographic and socioeconomic status, mental health (Patient Health Questionnaire [PHQ]-9 and Generalized Anxiety Disorder [GAD]-7 scale score), cognitive function (Montreal Cognitive Assessment [MoCA] score), and 2-dimensional echocardiograms. The original sample used to develop the predictive model and the validation sample had similar proportions of patients with an adverse event within 30 days (30% vs 29%, p = 0.35) and 90 days (52% vs 49%, p = 0.36). Applying the predicted risk score to the validation sample provided very good discriminatory power (C-statistic = 0.77) in the prediction of 30-day readmission or death. This discrimination was greater for predicting 30-day death (C-statistic = 0.85) than for predicting 30-day readmission (C-statistic = 0.73). There was a small difference in the performance of the predictive model among patients with either a left ventricular ejection fraction of <40% or a left ventricular ejection fraction of ≥40%, but an attenuation in discrimination when used to predict longer-term adverse outcomes. In conclusion, our findings confirm the generalizability of the predictive model that may be a powerful tool for targeting high-risk patients with HF for intensive management.