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Caddy HT, Thomas HJ, Kelsey LJ, Smith KJ, Doyle BJ, Green DJ. Comparison of computational fluid dynamics with transcranial Doppler ultrasound in response to physiological stimuli. Biomech Model Mechanobiol 2024; 23:255-269. [PMID: 37805938 PMCID: PMC10902019 DOI: 10.1007/s10237-023-01772-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023]
Abstract
Cerebrovascular haemodynamics are sensitive to multiple physiological stimuli that require synergistic response to maintain adequate perfusion. Understanding haemodynamic changes within cerebral arteries is important to inform how the brain regulates perfusion; however, methods for direct measurement of cerebral haemodynamics in these environments are challenging. The aim of this study was to assess velocity waveform metrics obtained using transcranial Doppler (TCD) with flow-conserving subject-specific three-dimensional (3D) simulations using computational fluid dynamics (CFD). Twelve healthy participants underwent head and neck imaging with 3 T magnetic resonance angiography. Velocity waveforms in the middle cerebral artery were measured with TCD ultrasound, while diameter and velocity were measured using duplex ultrasound in the internal carotid and vertebral arteries to calculate incoming cerebral flow at rest, during hypercapnia and exercise. CFD simulations were developed for each condition, with velocity waveform metrics extracted in the same insonation region as TCD. Exposure to stimuli induced significant changes in cardiorespiratory measures across all participants. Measured absolute TCD velocities were significantly higher than those calculated from CFD (P range < 0.001-0.004), and these data were not correlated across conditions (r range 0.030-0.377, P range 0.227-0.925). However, relative changes in systolic and time-averaged velocity from resting levels exhibited significant positive correlations when the distinct techniques were compared (r range 0.577-0.770, P range 0.003-0.049). Our data indicate that while absolute measures of cerebral velocity differ between TCD and 3D CFD simulation, physiological changes from resting levels in systolic and time-averaged velocity are significantly correlated between techniques.
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Affiliation(s)
- Harrison T Caddy
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Hannah J Thomas
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
| | - Lachlan J Kelsey
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia
- School of Engineering, The University of Western Australia, Perth, Australia
| | - Kurt J Smith
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
- Cerebrovascular Health, Exercise, and Environmental Research Sciences Laboratory, University of Victoria, Victoria, Canada
| | - Barry J Doyle
- Vascular Engineering Laboratory, Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Australia and the UWA Centre for Medical Research, The University of Western Australia, Perth, Australia.
- School of Engineering, The University of Western Australia, Perth, Australia.
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Perth, Australia
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Penny-Dimri JC, Bergmeir C, Reid CM, Williams-Spence J, Cochrane AD, Smith JA. Paying attention to cardiac surgical risk: An interpretable machine learning approach using an uncertainty-aware attentive neural network. PLoS One 2023; 18:e0289930. [PMID: 37647308 PMCID: PMC10468047 DOI: 10.1371/journal.pone.0289930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/29/2023] [Indexed: 09/01/2023] Open
Abstract
Machine learning (ML) is increasingly applied to predict adverse postoperative outcomes in cardiac surgery. Commonly used ML models fail to translate to clinical practice due to absent model explainability, limited uncertainty quantification, and no flexibility to missing data. We aimed to develop and benchmark a novel ML approach, the uncertainty-aware attention network (UAN), to overcome these common limitations. Two Bayesian uncertainty quantification methods were tested, generalized variational inference (GVI) or a posterior network (PN). The UAN models were compared with an ensemble of XGBoost models and a Bayesian logistic regression model (LR) with imputation. The derivation datasets consisted of 153,932 surgery events from the Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) Cardiac Surgery Database. An external validation consisted of 7343 surgery events which were extracted from the Medical Information Mart for Intensive Care (MIMIC) III critical care dataset. The highest performing model on the external validation dataset was a UAN-GVI with an area under the receiver operating characteristic curve (AUC) of 0.78 (0.01). Model performance improved on high confidence samples with an AUC of 0.81 (0.01). Confidence calibration for aleatoric uncertainty was excellent for all models. Calibration for epistemic uncertainty was more variable, with an ensemble of XGBoost models performing the best with an AUC of 0.84 (0.08). Epistemic uncertainty was improved using the PN approach, compared to GVI. UAN is able to use an interpretable and flexible deep learning approach to provide estimates of model uncertainty alongside state-of-the-art predictions. The model has been made freely available as an easy-to-use web application demonstrating that by designing uncertainty-aware models with innately explainable predictions deep learning may become more suitable for routine clinical use.
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Affiliation(s)
- Jahan C. Penny-Dimri
- Department of Surgery, School of Clinical Sciences at Monash Health, Monash University, Melbourne, Vic, Australia
| | - Christoph Bergmeir
- Department of Computer Science and Artificial Intelligence, University of Granada, Granada, Spain
- Department of Data Science and Artificial Intelligence, Faculty of Information Technology, Monash University, Melbourne, Vic, Australia
| | - Christopher M. Reid
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Vic, Australia
| | - Jenni Williams-Spence
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Vic, Australia
| | - Andrew D. Cochrane
- Department of Surgery, School of Clinical Sciences at Monash Health, Monash University, Melbourne, Vic, Australia
| | - Julian A. Smith
- Department of Surgery, School of Clinical Sciences at Monash Health, Monash University, Melbourne, Vic, Australia
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Zeng C, Bennell K, Yang Z, Nguyen USDT, Lu N, Wei J, Lei G, Zhang Y. Risk of venous thromboembolism in knee, hip and hand osteoarthritis: a general population-based cohort study. Ann Rheum Dis 2020; 79:1616-1624. [PMID: 32938637 PMCID: PMC7677492 DOI: 10.1136/annrheumdis-2020-217782] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Osteoarthritis is a leading cause of immobility and joint replacement, two strong risk factors for venous thromboembolism (VTE). We aimed to examine the relation of knee, hip and hand osteoarthritis to the risk of VTE and investigate joint replacement as a potential mediator. METHODS We conducted three cohort studies using data from The Health Improvement Network. Up to five individuals without osteoarthritis were matched to each case of incident knee (n=20 696), hip (n=10 411) or hand (n=6329) osteoarthritis by age, sex, entry time and body mass index. We examined the relation of osteoarthritis to VTE (pulmonary embolism and deep vein thrombosis) using a multivariable Cox proportional hazard model. RESULTS VTE developed in 327 individuals with knee osteoarthritis and 951 individuals without osteoarthritis (2.7 vs 2.0 per 1000 person-years), with multivariable-adjusted HR being 1.38 (95% CI 1.23 to 1.56). The indirect effect (HR) of knee osteoarthritis on VTE through knee replacement was 1.07 (95% CI 1.01 to 1.15), explaining 24.8% of its total effect on VTE. Risk of VTE was higher in hip osteoarthritis than non-osteoarthritis (3.3 vs 1.8 per 1000 person-years; multivariable-adjusted HR=1.83, 95% CI 1.56 to 2.13). The indirect effect through hip replacement yielded an HR of 1.14 (95% CI 1.04 to 1.25), explaining 28.1% of the total effect. No statistically significant difference in VTE risk was observed between hand osteoarthritis and non-osteoarthritis (1.5 vs 1.6 per 1000 person-years; multivariable-adjusted HR=0.88, 95% CI 0.67 to 1.16). CONCLUSION Our large population-based cohort study provides the first evidence that knee or hip osteoarthritis, but not hand osteoarthritis, was associated with an increased risk of VTE, and such an association was partially mediated through knee or hip replacement.
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Affiliation(s)
- Chao Zeng
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China
- Division of Rheumatology, Allergy, and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Mongan Institute, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Hunan Key Laboratory of Joint Degeneration and Injury, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center of Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Kim Bennell
- Centre for Health, Exercise and Sports Medicine, The University of Melbourne, Melbourne, Victoria, Australia
| | - Zidan Yang
- Hunan Key Laboratory of Joint Degeneration and Injury, Xiangya Hospital, Central South University, Changsha, China
| | - Uyen-Sa D T Nguyen
- Department of Biostatistics and Epidemiology, University of North Texas Health Science Center, School of Public Health, Fort Worth, Texas, USA
| | - Na Lu
- Arthritis Research Centre, Richmond, British Columbia, Canada
| | - Jie Wei
- Division of Rheumatology, Allergy, and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Mongan Institute, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Health Management Center, Xiangya Hospital, Central South University, Changsha, China
| | - Guanghua Lei
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, China
- Hunan Key Laboratory of Joint Degeneration and Injury, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center of Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yuqing Zhang
- Division of Rheumatology, Allergy, and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- The Mongan Institute, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Middelweerd A, te Velde SJ, Abbott G, Timperio A, Brug J, Ball K. Do intrapersonal factors mediate the association of social support with physical activity in young women living in socioeconomically disadvantaged neighbourhoods? A longitudinal mediation analysis. PLoS One 2017; 12:e0173231. [PMID: 28301538 PMCID: PMC5354271 DOI: 10.1371/journal.pone.0173231] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 02/18/2017] [Indexed: 11/21/2022] Open
Abstract
Background Levels of physical activity (PA) decrease when transitioning from adolescence into young adulthood. Evidence suggests that social support and intrapersonal factors (self-efficacy, outcome expectations, PA enjoyment) are associated with PA. The aim of the present study was to explore whether cross-sectional and longitudinal associations of social support from family and friends with leisure-time PA (LTPA) among young women living in disadvantaged areas were mediated by intrapersonal factors (PA enjoyment, outcome expectations, self-efficacy). Methods Survey data were collected from 18–30 year-old women living in disadvantaged suburbs of Victoria, Australia as part of the READI study in 2007–2008 (T0, N = 1197), with follow-up data collected in 2010–2011 (T1, N = 357) and 2012–2013 (T2, N = 271). A series of single-mediator models were tested using baseline (T0) and longitudinal data from all three time points with residual change scores for changes between measurements. Results Cross-sectional analyses showed that social support was associated with LTPA both directly and indirectly, mediated by intrapersonal factors. Each intrapersonal factor explained between 5.9–37.5% of the associations. None of the intrapersonal factors were significant mediators in the longitudinal analyses. Conclusions Results from the cross-sectional analyses suggest that the associations of social support from family and from friends with LTPA are mediated by intrapersonal factors (PA enjoyment, outcome expectations and self-efficacy). However, longitudinal analyses did not confirm these findings.
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Affiliation(s)
- Anouk Middelweerd
- Department of Epidemiology & Biostatistics and the EMGO+ Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Saskia J. te Velde
- Department of Epidemiology & Biostatistics and the EMGO+ Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Gavin Abbott
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong Victoria, Australia
| | - Anna Timperio
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong Victoria, Australia
| | - Johannes Brug
- Amsterdam School of Communication Research, University of Amsterdam, Amsterdam, the Netherlands
| | - Kylie Ball
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong Victoria, Australia
- * E-mail:
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