Melbourne Medical School Collected Works - Research Publications

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    Applications of artificial intelligence in echocardiography
    Sen, J ; Marwick, TH (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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    Antihypertensive therapies in moderate or severe aortic stenosis: a systematic review and meta-analysis
    Sen, J ; Chung, E ; Neil, C ; Marwick, T (BMJ PUBLISHING GROUP, 2020-01-01)
    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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    Metformin treatment in heart failure with preserved ejection fraction: a systematic review and meta-regression analysis
    Halabi, A ; Sen, J ; Huynh, Q ; Marwick, TH (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.