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Pu W, Chen Y, Zhao S, Yu T, Lin H, Gao H, Xie S, Zhang X, Zhang B, Li C, Lian K, Xie X. Computing pulsatile blood flow of coronary artery under incomplete boundary conditions. Med Eng Phys 2024; 130:104193. [PMID: 39160034 DOI: 10.1016/j.medengphy.2024.104193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 05/27/2024] [Accepted: 06/08/2024] [Indexed: 08/21/2024]
Abstract
BACKGROUND Accurate measurement of pulsatile blood flow in the coronary arteries enables coronary wave intensity analysis, which can serve as an indicator for assessing coronary artery physiology and myocardial viability. Computational fluid dynamics (CFD) methods integrating coronary angiography images and fractional flow reserve (FFR) offer a novel approach for computing mean coronary blood flow. However, previous methods neglect the inertial effect of blood flow, which may have great impact on pulsatile blood flow calculation. To improve the accuracy of pulsatile blood flow calculation, a novel CFD based method considering the inertia term is proposed. METHODS A flow resistance model based on Pressure-Flow vs.Time curves is proposed to model the resistance of the epicardial artery. The parameters of the flow resistance model can be fitted from the simulated pulsating flow rates and pressure drops of a specific mode. Then, pulsating blood flow can be calculated by combining the incomplete pressure boundary conditions under pulsating conditions which are easily obtained in clinic. Through simulation experiments, the effectiveness of the proposed method is validated in idealized and reconstructed 3D model of coronary artery. The impacts of key parameters for generating the simulated pulsating flow rates and pressure drops on the accuracy of pulsatile blood flow calculation are also investigated. RESULTS For the idealized model, the previously proposed Pressure-Flow model has a significant leading effect on the computed blood flow waveform in the moderate model, and this leading effect disappears with the increase of the degree of stenosis. The improved model proposed in this paper has no leading effect, the root mean square error (RMSE) of the proposed model is low (the left coronary mode:≤0.0160, the right coronary mode:≤0.0065) for all simulated models, and the RMSE decreases with an increase of stenosis. The RMSE is consistently small (≤0.0217) as the key parameters of the proposed method vary in a large range. It is verified in the reconstructed model that the proposed model significantly reduces the RMSE of patients with moderate stenosis (the Pressure-Flow model:≤0.0683, the Pressure-Flow vs.Time model:≤0.0297), and the obtained blood flow waveform has a higher coincidence with the simulated reference waveform. CONCLUSIONS This paper confirms that ignoring the effect of inertia term can significantly affect the accuracy of calculating pulsatile blood flow in moderate stenosis lesions, and the new method proposed in this paper can significantly improves the accuracy of calculating pulsatile blood flow in moderate stenosis lesions. The proposed method provides a convenient clinical method for obtaining pressure-synchronized blood flow, which is expected to facilitate the application of waveform analysis in the diagnosis of coronary artery disease.
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Affiliation(s)
- WenJun Pu
- Department of Information Engineering, School of Electronics and Information, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Yan Chen
- Department of Cardiology, No. 971 Hospital of the PLA Navy, Qingdao, Shandong, China
| | - Shuai Zhao
- Department of Cardiology, Air Force Hospital of Western Theater Command, Chengdu, Sichuan, China
| | - Tiantong Yu
- Department of Cardiology, Xijing Hospital, Forth Military Medical University, Xi'an, Shaanxi, China
| | - Heqiang Lin
- Department of Information Engineering, School of Electronics and Information, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Haokao Gao
- Department of Cardiology, Xijing Hospital, Forth Military Medical University, Xi'an, Shaanxi, China
| | - Songyun Xie
- Department of Information Engineering, School of Electronics and Information, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Xi Zhang
- Department of Cardiology, Xijing Hospital, Changle West Road, Xi'an, Shaanxi, China
| | - Bohui Zhang
- School of Public Health, Shaanxi University of Chinese Medicine, Xixian New District, Xi'an, Shaanxi, China
| | - Chengxiang Li
- Department of Cardiology, Xijing Hospital, Forth Military Medical University, Xi'an, Shaanxi, China
| | - Kun Lian
- Department of Cardiology, Xijing Hospital, Forth Military Medical University, Xi'an, Shaanxi, China.
| | - Xinzhou Xie
- Department of Information Engineering, School of Electronics and Information, Northwestern Polytechnical University, Xi'an, Shaanxi, China.
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Francis N, Selwanos PP, Yacoub MH, Parker KH. The Use of Maximum Entropy to Enhance Wave Intensity Analysis: An Application to Coronary Arteries in Hypertrophic Obstructive Cardiomyopathy. Front Cardiovasc Med 2021; 8:701267. [PMID: 34513947 PMCID: PMC8429819 DOI: 10.3389/fcvm.2021.701267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/05/2021] [Indexed: 01/09/2023] Open
Abstract
Background: Wave intensity analysis is useful for analyzing coronary hemodynamics. Much of its clinical application involves the identification of waves indicated by peaks in the wave intensity and relating their presence or absence to different cardiovascular events. However, the analysis of wave intensity peaks can be problematic because of the associated noise in the measurements. This study shows how wave intensity analysis can be enhanced by using a Maximum Entropy Method (MEM). Methods: We introduce a MEM to differentiate between "peaks" and "background" in wave intensity waveforms. We apply the method to the wave intensity waveforms measured in the left anterior descending coronary artery from 10 Hypertrophic Obstructive Cardiomyopathy (HOCM) and 11 Controls with normal cardiac function. We propose a naming convention for the significant waves and compare them across the cohorts. Results: Using a MEM enhances wave intensity analysis by identifying twice as many significant waves as previous studies. The results are robust when MEM is applied to the log transformed wave intensity data and when all of the measured data are used. Comparing waves across cohorts, we suggest that the absence of a forward expansion wave in HOCM can be taken as an indication of HOCM. Our results also indicate that the backward compression waves in HOCM are significantly larger than in Controls; unlike the forward compression waves where the wave energy in Controls is significantly higher than in HOCM. Comparing the smaller secondary waves revealed by MEM, we find some waves that are present in the majority of Controls and absent in almost all HOCM, and other waves that are present in some HOCM patients but entirely absent in Controls. This suggests some diagnostic utility in the clinical measurement of these waves, which can be a positive sign of HOCM or a subgroup with a particular pathology. Conclusion: The MEM enhances wave intensity analysis by identifying many more significant waves. The method is novel and can be applied to wave intensity analysis in all arteries. As an example, we show how it can be useful in the clinical study of hemodynamics in the coronary arteries in HOCM.
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Affiliation(s)
- Nadine Francis
- Biomedical Engineering and Innovation Laboratory, Department of Research, Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
- Department of Bioengineering, Imperial College, London, United Kingdom
| | - Peter P. Selwanos
- Department of Cardiology, Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
| | - Magdi H. Yacoub
- Biomedical Engineering and Innovation Laboratory, Department of Research, Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
- Department of Cardiology, Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
- Harefield Heart Science Centre, Harefield, United Kingdom
- Department of Surgery, Aswan Heart Centre, Magdi Yacoub Heart Foundation, Aswan, Egypt
- National Heart and Lung Institute, Imperial College, London, United Kingdom
| | - Kim H. Parker
- Department of Bioengineering, Imperial College, London, United Kingdom
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Bruining N, Cummins P. Identifying cardiac pathologies with coronary wave intensity analysis: an enrichment to the ever-expanding coronary haemodynamics armamentarium? Eur Heart J 2018; 39:1815-1817. [PMID: 29346546 DOI: 10.1093/eurheartj/ehx817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Nico Bruining
- Eramus MC, Thoraxcenter, Department of Cardiology, Rotterdam, The Netherlands
| | - Paul Cummins
- Eramus MC, Thoraxcenter, Department of Cardiology, Rotterdam, The Netherlands
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