Melbourne Medical School Collected Works - Research Publications
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ItemCost-Effectiveness of Obstructive Sleep Apnea Screening and Treatment Before Catheter Ablation for Symptomatic Atrial Fibrillation.(Japanese Circulation Society, 2020-08-27)Background: Although management of obstructive sleep apnea (OSA) has been recommended to improve outcomes of catheter ablation (CA) in patients with symptomatic atrial fibrillation (AF), the most cost-effective way of preprocedural OSA screening is undetermined. This study assessed the cost-effectiveness of OSA management before CA for symptomatic AF. Methods and Results: A Markov model was developed to assess the cost-effectiveness of 3 OSA detection strategies before CA: no screening; Type 3 portable monitor (PM)-guided screening; and polysomnography (PSG)-guided screening. The target population consisted of a hypothetical cohort of patients aged 65 years with symptomatic AF, with 50% prevalence of OSA. We used a 5-year horizon, with sensitivity analyses for significant variables and scenario analyses for lower and higher OSA prevalence (30% and 70%, respectively). In the base-case, both types of OSA screening were dominant (less costly and more effective) relative to no screening. Although PSG-guided management was more effective than PM-guided management, it was more costly and therefore did not show clear benefit. These findings were replicated in cohorts with lower and higher OSA risks. Conclusions: OSA screening before CA is cost-effective in patients with symptomatic AF, with PM screening being the most cost-effective. Physicians should consider OSA management using this simple tool in the decision making for treatment of symptomatic AF.
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ItemRole of cardiovascular imaging in cancer patients receiving cardiotoxic therapies: a position statement on behalf of the Heart Failure Association (HFA), the European Association of Cardiovascular Imaging (EACVI) and the Cardio-Oncology Council of the European Society of Cardiology (ESC)(WILEY, 2020-09)Cardiovascular (CV) imaging is an important tool in baseline risk assessment and detection of CV disease in oncology patients receiving cardiotoxic cancer therapies. This position statement examines the role of echocardiography, cardiac magnetic resonance, nuclear cardiac imaging and computed tomography in the management of cancer patients. The Imaging and Cardio-Oncology Study Groups of the Heart Failure Association (HFA) of the European Society of Cardiology (ESC) in collaboration with the European Association of Cardiovascular Imaging (EACVI) and the Cardio-Oncology Council of the ESC have evaluated the current evidence for the value of modern CV imaging in the cardio-oncology field. The most relevant echocardiographic parameters, including global longitudinal strain and three-dimensional ejection fraction, are proposed. The protocol for baseline pre-treatment evaluation and specific surveillance algorithms or pathways for anthracycline chemotherapy, HER2-targeted therapies such as trastuzumab, vascular endothelial growth factor tyrosine kinase inhibitors, BCr-Abl tyrosine kinase inhibitors, proteasome inhibitors and immune checkpoint inhibitors are presented. The indications for CV imaging after completion of oncology treatment are considered. The typical consequences of radiation therapy and the possibility of their identification in the long term are also summarized. Special populations are discussed including female survivors planning pregnancy, patients with carcinoid disease, patients with cardiac tumours and patients with right heart failure. Future directions and ongoing CV imaging research in cardio-oncology are discussed.
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ItemCoronary artery calcium scoring in cardiovascular risk assessment of people with family histories of early onset coronary artery disease(WILEY, 2020-08)OBJECTIVES: To assess the predictive value of the Australian absolute cardiovascular disease risk (ACVDR) calculator and other assessment tools for identifying Australians with family histories of early onset coronary artery disease (CAD) who have coronary artery calcification. DESIGN, SETTING, PARTICIPANTS: People without known CAD were recruited at seven Australian hospitals, October 2016 - January 2019. Participants were aged 40-70 years, had a family history of early onset CAD, and a 5-year ACVDR of 2-15%. MAIN OUTCOME MEASURES: CT coronary artery calcium score greater than zero (any coronary calcification) or greater than 100 (calcification warranting lipid therapy). RESULTS: 1059 participants were recruited; 477 (45%) had non-zero coronary artery calcium scores (median 5-year ACVDR, 4.8% [IQR, 2.9-7.6%]; median coronary artery calcium score, 41.7 [IQR, 8-124]); 582 (55%) did not (median 5-year ACVDR, 3.2% [IQR, 2.0-4.6%]). Of 151 participants with calcium scores of 100 or more, 116 (77%) were deemed to be at low cardiovascular risk by Australian guidelines, while 14 of 75 participants at intermediate risk (19%) had zero calcium scores. The sensitivity of the ACVDR calculator for identifying people with non-zero calcium scores (area under receiver operator curve [AUC], 0.674) was lower than that of the pooled cohort equation (AUC, 0.711; P < 0.001). ACVDR (10-year)- and Multi-Ethnic Study of Atherosclerosis (MESA)-predicted risk categories concurred for 511 participants (48%); classifications were concordant for 925 participants (87%) when the ACVDR was supplemented by calcium scores. CONCLUSIONS: Coronary artery calcium scoring should be considered as part of the heart health check for patients at intermediate ACVDR risk and with family histories of early onset CAD. Alternative risk calculators may better select such patients for further diagnostic testing and primary prevention therapy. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN 12614001294640; 11 December 2014 (prospective).
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ItemIndependence of coronary artery disease to subclinical left ventricular dysfunction(WILEY, 2020-05)OBJECTIVE: Epicardial atherosclerosis and heart failure while distinct clinical entities share common pathophysiological features including endothelial dysfunction and inflammation. Presence of subclinical disease could lead to early diagnosis and intervention in the other. The aim of our study was to assess the association between coronary calcium score (CCS), conventional cardiovascular risk factors, and echocardiographic markers of subclinical left ventricular dysfunction (S-LVD). METHODS: One hundred and fifty-nine participants aged 40-70 years with intermediate risk of coronary artery disease (5-year risk of 2%-15%) were identified. Computed tomography (CT) CCS and 2-D transthoracic echocardiography were performed. Main outcomes included presence of subclinical left ventricular dysfunction defined by reduced average global longitudinal strain, left atrial volume enlargement, and elevated E/e'. RESULTS: Fifteen participants had evidence of subclinical LV dysfunction (8 with systolic dysfunction and 7 with diastolic dysfunction) and 85 participants had CCS > 0. CCS > 0 was present in 10 participants with S-LVD compared to 75 participants without S-LVD (67% vs 53%, P = .47). There was no significant difference between in mean GLS (19.2 vs 19.5, P = .14), E/e' (7.2 vs 7.5 P = .33) in those without or with coronary artery calcium. Elevated CCS was also not associated with a higher tertiles of indexed LV mass (OR 1.15, P = .49) or index left atrial volume (OR 1.15, P = .49). CONCLUSIONS: In an asymptomatic, low-intermediate-risk group, mechanistic processes that lead to atherosclerosis are not directly associated with subclinical LV dysfunction.
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ItemAortic Thickness: A Forgotten Paradigm in Risk Stratification of Aortic Disease.(Georg Thieme Verlag KG, 2020-10)BACKGROUND: This study aimed at risk-stratifying aortic dilatation using aortic wall thickness (AWT) and comparing methods of AWT assessment. METHODS: Demographic, epidemiological, and perioperative data on 72 consecutive aortic surgeries (age = 62 years[standard deviation (SD) = 12] years) performed by a single surgeon were collected from hospital database. Aortic thickness was measured on computed tomography scans, as well as intraoperatively in four quadrants, at the level of aortic sinuses, as well as midascending aorta, using calipers. Aortic wall stress was calculated using standard mathematical formulae. RESULTS: The ascending aorta was 48.2 (SD = 8) mm and the mean thickness at ascending aorta level was 1.9 (SD = 0.3) mm. There was congruence between imaging and intraoperative measurements of thickness, as well as between the radiologist and surgeon. Preoperatively, 16 patients had multiple imaging studies showing an average rate of growth of 1.2 mm per year without significant difference in thickness. The wider the aorta, the thinner was the lateral or convex wall. Aortic stenosis (p = 0.01), lateral to medial wall thickness ratio (p = 0.04), and history of hypertension (p = 0.00), all had protective effect on aortic root stress. The ascending aortic stress was directly affected by age (p = 0.03) and inversely related to lateral to medial wall thickness ratio (p = 0.03). CONCLUSION: Aortic thickness can be measured preoperatively and easily confirmed intraoperatively. Risk stratification based on both aortic thickness and diameter (stress calculations) would better predict acute aortic events in dilated aortas and define aortic resection criteria more objectively.
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ItemApplications of artificial intelligence in echocardiography(Heart and Metabolism, 2020-01-01)Artificial intelligence (AI) is a significant technological advance that underlies many aspects of modern life. Computer-aided detection is increasingly being applied to cardiovascular imaging such as echocardiography. AI improves the accuracy and reliability of echocardiographic measurements, reduces diagnostic errors, and minimizes interobserver variability. Research of, access to, and investment in AI-enhanced echocardiography has the potential to improve the diagnosis of cardiovascular disease (CVD), particularly in regional and remote areas, and allows for prognostication and risk stratification of age-related CV events. This review describes how AI-enhanced echocardiography can lead to improvements in image interpretation and in the diagnosis and prognostication of CVD. It also outlines the challenges precluding widespread adoption of AI tools in echocardiographic practice at the current time.
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ItemNo Preview AvailableMultimodality Cardiovascular Imaging in the Midst of the COVID-19 Pandemic(ELSEVIER SCIENCE INC, 2020-07)
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ItemAntihypertensive therapies in moderate or severe aortic stenosis: a systematic review and meta-analysis(BMJ PUBLISHING GROUP, 2020)BACKGROUND: Hypertension confers a poor prognosis in moderate or severe aortic stenosis (AS), however, antihypertensive therapy (AHT) is often not prescribed due to the perceived deleterious effects of vasodilation and negative inotropes. OBJECTIVE: To assess the efficacy and safety outcomes of AHT in adults with moderate or severe AS. DESIGN: Systematic review and meta-analysis. DATA SOURCES: The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and grey literature were searched without language restrictions up to 9 September 2019. STUDY ELIGIBILITY CRITERIA, APPRAISAL AND SYNTHESIS METHODS: Two independent reviewers performed screening, data extraction and risk of bias assessments from a systematic search of observational studies and randomised controlled trials comparing AHT with a placebo or no AHT in adults with moderate or severe AS for any parameter of efficacy and safety outcomes. Conflicts were resolved by the third reviewer. Meta-analysis with pooled effect sizes using random-effects model, were estimated in R. MAIN OUTCOME MEASURES: Mortality, Left Ventricular (LV) Mass Index, systolic blood pressure, diastolic blood pressure and LV ejection fraction RESULTS: From 3025 publications, 31 studies (26 500 patients) were included in the qualitative synthesis and 24 studies in the meta-analysis. AHT was not associated with mortality when all studies were pooled, but heterogeneity was substantial across studies. The effect size of AHT differed according to drug class. Renin-angiotensin-aldosterone system inhibitors (RAASi) were associated with reduced risk of mortality (Pooled HR 0.58, 95% CI 0.43 to 0.80, p=0.006), The differences in changes of haemodynamic or echocardiographic parameters from baseline with and without AHT did not reach statistical significance. CONCLUSION: AHT appears safe, is well tolerated. RAASi were associated with clinical benefit in patients with moderate or severe AS.
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ItemRationale and design of a risk-guided strategy for reducing readmissions for acute decompensated heart failure: the Risk-HF study(WILEY PERIODICALS, INC, 2020-10)AIMS: Heart failure (HF) readmission commonly arises owing to insufficient patient knowledge and failure of recognition of the early stages of recurrent fluid congestion. In previous work, we developed a score to predict short-term hospital readmission and showed that higher-risk patients benefit most from a disease management programme (DMP) that included enhancing knowledge and education by a nurse. We aim to evaluate the effectiveness of a novel, nurse-led HF DMP in selected patients at high risk of short-term hospital readmission, using ultrasound-guided diuretic management and artificial intelligence to enhance HF knowledge in an outpatient setting. METHODS AND RESULTS: Risk-HF is a prospective multisite randomized controlled trial that will allocate 404 patients hospitalized with acute decompensated HF, and ≥33% risk of readmission and/or death at 30 days, into risk-guided nurse intervention (DMP-Plus group) compared with usual care. Intervention elements include (i) fluid management with a handheld ultrasound (HHU) device at point of care; (ii) post-discharge follow-up; (iii) optimal programmed drug titration; (iv) better transition of care; (v) intensive self-care education via an avatar-based 'digital health coach'; and (vi) exercise guidance through the digital coach. Usual care involves standard post-discharge hospital care. The primary outcome is reduced death and/or hospital readmissions at 30 days post-discharge, and secondary outcomes include quality of life, fluid management efficacy, and feasibility and patient engagement. Assuming that our intervention will reduce readmissions and/or deaths by 50%, with a 1:1 ratio of intervention vs. usual care, we plan to randomize 404 patients to show a difference at a statistical power of 80%, using a two-sided alpha of 0.05. We anticipate this recruitment will be achieved by screening 2020 hospitalized HF patients for eligibility. An 8 week pilot programme of our digital health coach in 21 HF patients, age > 75 years, showed overall improvements in quality of life (13 of 21), self-care (12 of 21), and HF knowledge (13 of 21). A pilot of the use of HHU by nurses showed that it was feasible and accurate. CONCLUSIONS: The Risk-HF trial will evaluate the effectiveness of a risk-guided intervention to improve HF outcomes and will evaluate the efficacy of trained HF nurses delivering a fluid management protocol that is guided by lung ultrasound with an HHU at point of care.
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ItemMetformin treatment in heart failure with preserved ejection fraction: a systematic review and meta-regression analysis(BMC, 2020-08-05)BACKGROUND: Observational series suggest a mortality benefit from metformin in the heart failure (HF) population. However, the benefit of metformin in HF with preserved ejection fraction (HFpEF) has yet to be explored. We performed a systematic review and meta-analysis to identify whether variation in EF impacts mortality outcomes in HF patients treated with metformin. METHODS: MEDLINE and EMBASE were searched up to October 2019. Observational studies and randomised trials reporting mortality in HF patients and the proportion of patients with an EF > 50% at baseline were included. Other baseline variables were used to assess for heterogeneity in treatment outcomes between groups. Regression models were used to determine the interaction between metformin and subgroups on mortality. RESULTS: Four studies reported the proportion of patients with a preserved EF and were analysed. Metformin reduced mortality in both preserved or reduced EF after adjustment with HF therapies such as angiotensin converting enzyme inhibitors (ACEi) and beta-blockers (β = - 0.2 [95% CI - 0.3 to - 0.1], p = 0.02). Significantly greater protective effects were seen with EF > 50% (p = 0.003). Metformin treatment with insulin, ACEi and beta-blocker therapy were also shown to have a reduction in mortality (insulin p = 0.002; ACEi p < 0.001; beta-blocker p = 0.017), whereas female gender was associated with worse outcomes (p < 0.001). CONCLUSIONS: Metformin treatment is associated with a reduction in mortality in patients with HFpEF.