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Ryu H, Wang X, Xie Z, Kim J, Liu Y, Bai W, Song Z, Song JW, Zhao Z, Kim J, Yang Q, Xie JJ, Keate R, Wang H, Huang Y, Efimov IR, Ameer GA, Rogers JA. Materials and Design Approaches for a Fully Bioresorbable, Electrically Conductive and Mechanically Compliant Cardiac Patch Technology. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303429. [PMID: 37518771 PMCID: PMC10520666 DOI: 10.1002/advs.202303429] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/07/2023] [Indexed: 08/01/2023]
Abstract
Myocardial infarction (MI) is one of the leading causes of death and disability. Recently developed cardiac patches provide mechanical support and additional conductive paths to promote electrical signal propagation in the MI area to synchronize cardiac excitation and contraction. Cardiac patches based on conductive polymers offer attractive features; however, the modest levels of elasticity and high impedance interfaces limit their mechanical and electrical performance. These structures also operate as permanent implants, even in cases where their utility is limited to the healing period of tissue damaged by the MI. The work presented here introduces a highly conductive cardiac patch that combines bioresorbable metals and polymers together in a hybrid material structure configured in a thin serpentine geometry that yields elastic mechanical properties. Finite element analysis guides optimized choices of layouts in these systems. Regular and synchronous contraction of human induced pluripotent stem cell-derived cardiomyocytes on the cardiac patch and ex vivo studies offer insights into the essential properties and the bio-interface. These results provide additional options in the design of cardiac patches to treat MI and other cardiac disorders.
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Goyal A. Image-based clustering and connected component labeling for rapid automated left and right ventricular endocardial volume extraction and segmentation in full cardiac cycle multi-frame MRI images of cardiac patients. Med Biol Eng Comput 2019; 57:1213-1228. [PMID: 30690663 DOI: 10.1007/s11517-019-01952-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 01/10/2019] [Indexed: 10/27/2022]
Abstract
A rapid method for left and right ventricular endocardial volume segmentation and clinical cardiac parameter calculation from MRI images of cardiac patients is presented. The clinical motivation is providing cardiologists a tool for assessing the cardiac function in a patient through the left ventricular endocardial volume's ejection fraction. A new method combining adapted fuzzy membership-based c-means pixel clustering and connected regions component labeling is used for automatic segmentation of the left and right ventricular endocardial volumes. This proposed pixel clustering with labeling approach avoids manual initialization or user intervention and does not require specifying the region of interest. This method fully automatically extracts the left and right ventricular endocardial volumes and avoids manual tracing on all MRI image frames in the complete cardiac cycle from systole to diastole. The average computational processing time per frame is 0.6 s, making it much more efficient than deformable methods, which need several iterations for the evolution of the snake or contour. Accuracy of the automated method presented herein was validated against manual tracing-based extraction, performed with the guidance of cardiac experts, on several MRI frames. Dice coefficients between the proposed automatic versus manual traced ventricular endocardial volume segmentations were observed to be 0.9781 ± 0.0070 (for left ventricular endocardial volume) and 0.9819 ± 0.0058 (for right ventricular endocardial volume), and the Pearson correlation coefficients were observed to be 0.9655 ± 0.0206 (for left ventricular endocardial volume) and 0.9870 ± 0.0131 (for right ventricular endocardial volume). Graphical abstract The left ventricular endocardial volume segmentation methodology illustrated as a series of algorithms.
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Affiliation(s)
- Ayush Goyal
- Department of Electrical Engineering and Computer Science, Frank H. Dotterweich College of Engineering, Texas A&M University - Kingsville, MSC 192, 700 University Blvd., Kingsville, TX, 78363-8202, USA.
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Yang F, Yang X, Teo SK, Lee G, Zhong L, Tan RS, Su Y. Multi-dimensional proprio-proximus machine learning for assessment of myocardial infarction. Comput Med Imaging Graph 2018; 70:63-72. [DOI: 10.1016/j.compmedimag.2018.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 08/13/2018] [Accepted: 09/21/2018] [Indexed: 10/28/2022]
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Zhao X, Tan RS, Tang HC, Teo SK, Su Y, Wan M, Leng S, Zhang JM, Allen J, Kassab GS, Zhong L. Left Ventricular Wall Stress Is Sensitive Marker of Hypertrophic Cardiomyopathy With Preserved Ejection Fraction. Front Physiol 2018; 9:250. [PMID: 29643812 PMCID: PMC5882847 DOI: 10.3389/fphys.2018.00250] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/06/2018] [Indexed: 11/23/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) patients present altered myocardial mechanics due to the hypertrophied ventricular wall and are typically diagnosed by the increase in myocardium wall thickness. This study aimed to quantify regional left ventricular (LV) shape, wall stress and deformation from cardiac magnetic resonance (MR) images in HCM patients and controls, in order to establish superior measures to differentiate HCM from controls. A total of 19 HCM patients and 19 controls underwent cardiac MR scans. The acquired MR images were used to reconstruct 3D LV geometrical models and compute the regional parameters (i.e., wall thickness, curvedness, wall stress, area strain and ejection fraction) based on the standard 16 segment model using our in-house software. HCM patients were further classified into four quartiles based on wall thickness at end diastole (ED) to assess the impact of wall thickness on these regional parameters. There was a significant difference between the HCM patients and controls for all regional parameters (P < 0.001). Wall thickness was greater in HCM patients at the end-diastolic and end-systolic phases, and thickness was most pronounced in segments at the septal regions. A multivariate stepwise selection algorithm identified wall stress index at ED (σi,ED) as the single best independent predictor of HCM (AUC = 0.947). At the cutoff value σi,ED < 1.64, both sensitivity and specificity were 94.7%. This suggests that the end-diastolic wall stress index incorporating regional wall curvature—an index based on mechanical principle—is a sensitive biomarker for HCM diagnosis with potential utility in diagnostic and therapeutic assessment.
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Affiliation(s)
- Xiaodan Zhao
- National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Ru-San Tan
- National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
| | - Hak-Chiaw Tang
- National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
| | - Soo-Kng Teo
- Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore
| | - Yi Su
- Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore
| | - Min Wan
- School of Information Engineering, Nanchang University, Nanchang, Jiangxi, China
| | - Shuang Leng
- National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Jun-Mei Zhang
- National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
| | - John Allen
- Duke-NUS Medical School, Singapore, Singapore
| | - Ghassan S Kassab
- California Medical Innovations Institute, San Diego, CA, United States
| | - Liang Zhong
- National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.,Duke-NUS Medical School, Singapore, Singapore
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Wong KKL, Wang D, Ko JKL, Mazumdar J, Le TT, Ghista D. Computational medical imaging and hemodynamics framework for functional analysis and assessment of cardiovascular structures. Biomed Eng Online 2017; 16:35. [PMID: 28327144 PMCID: PMC5359907 DOI: 10.1186/s12938-017-0326-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/13/2017] [Indexed: 11/10/2022] Open
Abstract
Cardiac dysfunction constitutes common cardiovascular health issues in the society, and has been an investigation topic of strong focus by researchers in the medical imaging community. Diagnostic modalities based on echocardiography, magnetic resonance imaging, chest radiography and computed tomography are common techniques that provide cardiovascular structural information to diagnose heart defects. However, functional information of cardiovascular flow, which can in fact be used to support the diagnosis of many cardiovascular diseases with a myriad of hemodynamics performance indicators, remains unexplored to its full potential. Some of these indicators constitute important cardiac functional parameters affecting the cardiovascular abnormalities. With the advancement of computer technology that facilitates high speed computational fluid dynamics, the realization of a support diagnostic platform of hemodynamics quantification and analysis can be achieved. This article reviews the state-of-the-art medical imaging and high fidelity multi-physics computational analyses that together enable reconstruction of cardiovascular structures and hemodynamic flow patterns within them, such as of the left ventricle (LV) and carotid bifurcations. The combined medical imaging and hemodynamic analysis enables us to study the mechanisms of cardiovascular disease-causing dysfunctions, such as how (1) cardiomyopathy causes left ventricular remodeling and loss of contractility leading to heart failure, and (2) modeling of LV construction and simulation of intra-LV hemodynamics can enable us to determine the optimum procedure of surgical ventriculation to restore its contractility and health This combined medical imaging and hemodynamics framework can potentially extend medical knowledge of cardiovascular defects and associated hemodynamic behavior and their surgical restoration, by means of an integrated medical image diagnostics and hemodynamic performance analysis framework.
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Affiliation(s)
- Kelvin K. L. Wong
- School of Medicine, University of Western Sydney, Campbelltown, Sydney, NSW 2560 Australia
- School of Medicine, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751 Australia
| | - Defeng Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jacky K. L. Ko
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories Hong Kong
| | - Jagannath Mazumdar
- Centre for Biomedical Engineering and School of Electrical and Electronics Engineering, University of Adelaide, Adelaide, SA 5005 Australia
| | - Thu-Thao Le
- National Heart Centre, Mistri Wing, 17 Third Hospital Avenue, Singapore, 168752 Singapore
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Doost SN, Zhong L, Su B, Morsi YS. The numerical analysis of non-Newtonian blood flow in human patient-specific left ventricle. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2016; 127:232-247. [PMID: 26849955 DOI: 10.1016/j.cmpb.2015.12.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
Recently, various non-invasive tools such as the magnetic resonance image (MRI), ultrasound imaging (USI), computed tomography (CT), and the computational fluid dynamics (CFD) have been widely utilized to enhance our current understanding of the physiological parameters that affect the initiation and the progression of the cardiovascular diseases (CVDs) associated with heart failure (HF). In particular, the hemodynamics of left ventricle (LV) has attracted the attention of the researchers due to its significant role in the heart functionality. In this study, CFD owing its capability of predicting detailed flow field was adopted to model the blood flow in images-based patient-specific LV over cardiac cycle. In most published studies, the blood is modeled as Newtonian that is not entirely accurate as the blood viscosity varies with the shear rate in non-linear manner. In this paper, we studied the effect of Newtonian assumption on the degree of accuracy of intraventricular hemodynamics. In doing so, various non-Newtonian models and Newtonian model are used in the analysis of the intraventricular flow and the viscosity of the blood. Initially, we used the cardiac MRI images to reconstruct the time-resolved geometry of the patient-specific LV. After the unstructured mesh generation, the simulations were conducted in the CFD commercial solver FLUENT to analyze the intraventricular hemodynamic parameters. The findings indicate that the Newtonian assumption cannot adequately simulate the flow dynamic within the LV over the cardiac cycle, which can be attributed to the pulsatile and recirculation nature of the flow and the low blood shear rate.
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Affiliation(s)
- Siamak N Doost
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia.
| | - Liang Zhong
- Duke-NUS Graduate Medical School, Singapore; National Heart Research Institute of Singapore, National Heart Centre, Singapore.
| | - Boyang Su
- National Heart Research Institute of Singapore, National Heart Centre, Singapore
| | - Yosry S Morsi
- Biomechanical and Tissue Engineering Lab, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Australia
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Khalafvand SS, Zhong L, Ng EYK. Three-dimensional CFD/MRI modeling reveals that ventricular surgical restoration improves ventricular function by modifying intraventricular blood flow. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:1044-1056. [PMID: 24753501 DOI: 10.1002/cnm.2643] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 01/10/2014] [Accepted: 03/22/2014] [Indexed: 06/03/2023]
Abstract
Surgical ventricular restoration (SVR) is designed to normalize distorted ventricular shape and size in patients with left ventricular (LV) dysfunction and akinetic and dyskinetic segments. This study is aimed to quantify the characteristics of LV as a pump for a case before and after SVR, which is followed by coronary artery bypass grafting (CABG). We hypothesize that SVR+CABG improves heart flow. A patient with heart failure had magnetic resonance (MR) scans before and 4 months after SVR. LV endocardial geometries were semi-automated segmented and reconstructed using our customized algorithm. The arbitrary Lagrangian-Eulerian formulation of Navier-Stokes equations was solved to derive the flow patterns and calculate pressure differences in LV. After SVR, LV ejection fraction increased from 34% to 48% in patient but was still lower than normal (70%). Second, LV vortices were stronger than pre-surgery but still weaker than normal. The maximum pressure differences between ventricular base and apex increased from 180 to 400 Pa during diastole, from 252 to 560 Pa during systole, respectively. As anticipated, SVR reduced LV volumes and augmented LV ejection fraction. Three-dimensional CFD/MRI modeling suggests that improved diastolic and systolic ventricular function after SVR is associated with changes in intraventricular blood flow.
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Affiliation(s)
- S S Khalafvand
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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The shape and function of the left ventricle in Ebstein's anomaly. Int J Cardiol 2013; 171:404-12. [PMID: 24411210 DOI: 10.1016/j.ijcard.2013.12.037] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 12/17/2013] [Indexed: 11/20/2022]
Abstract
BACKGROUND Left ventricular (LV) failure is common in Ebstein's anomaly, though remains poorly understood. We investigated whether shape deformity impacts LV function. METHODS Three-dimensional models of the right ventricle (RV) and LV from 29 adult Ebstein's patients and nine normal subjects were generated from cardiac magnetic resonance image tracings. LV end diastolic (ED) shape, systolic function, septal motion and ventricular interaction were analyzed. RESULTS LV ED volume index was normal in Ebstein's (75 ± 19 vs. 78 ± 11 ml/m(2) in normals, p=0.50) but the LV was basally narrowed and modestly dilated apically. LV function was reduced globally (ejection fraction (EF) 41 ± 7 vs. 57 ± 5% in normals, p<0.0001) and regionally (decreased mean segment displacement at end systole (ES) in 12/16 segments, basal Z-scores -2.1 to -1.0). Septal dyskinesis was suggested by outward mean segment displacement in at least one basal septal segment in 25 patients (86%) but refuted by septal thickening in 14 (48%), normal septal curvature at ED and ES, and by visually evident basal LV anterior translation in 27 patients (93%). LV EF correlated better with normalized tricuspid annular plane systolic excursion (r=0.70) than with RV EF (r=0.42) or RVEDVI (r=0.18). CONCLUSIONS Although the Ebstein's LV has preserved volume, it exhibits basal narrowing, modest apical dilation and global hypokinesis. The apparent basal septal dyskinesis observed in most patients is likely attributable to anterior cardiac translation rather than true paradoxical motion. LV EF is unaffected by RV volume, correlating well instead with RV longitudinal shortening.
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Su Y, Zhong L, Lim CW, Ghista D, Chua T, Tan RS. A geometrical approach for evaluating left ventricular remodeling in myocardial infarct patients. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2012; 108:500-510. [PMID: 21507502 DOI: 10.1016/j.cmpb.2011.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 02/14/2011] [Accepted: 03/16/2011] [Indexed: 05/30/2023]
Abstract
A computational method for quantifying left ventricle (LV) remodeling using 3D mesh models reconstructed from magnetic resonance imaging is proposed. The underlying geometry of the LV mesh is obtained by using a quadric fitting method, and its quantification is performed by using a curvedness shape descriptor. To achieve robustness, we have performed detailed studies of the effects of n-ring parameter selection on the accuracy of this method with in vitro and in vivo LV models. We have found that curvedness calculations based on a 5-ring selection can accurately depict anomalies in LV shape despite the presence of noise due to manual image segmentation. Our studies show that patients after myocardial infarction exhibit significant LV shape alteration in terms of curvedness, in particular at the apex. The diastole-to-systole change in regional curvedness was significantly lower suggesting regional differences in hypokinesis due to infarcted myocardium. This approach may add new insights into ventricular deformation and enable better discrimination between normal and pathologic conditions.
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Affiliation(s)
- Yi Su
- Institute of High Performance Computing, 1 Fusionopolis Way #16-16 Connexis, S138632, Singapore
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Zhong L, Gobeawan L, Su Y, Tan JL, Ghista D, Chua T, Tan RS, Kassab G. Right ventricular regional wall curvedness and area strain in patients with repaired tetralogy of Fallot. Am J Physiol Heart Circ Physiol 2011; 302:H1306-16. [PMID: 22210750 DOI: 10.1152/ajpheart.00679.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A quantitative understanding of right ventricular (RV) remodeling in repaired tetralogy of Fallot (rTOF) is crucial for patient management. The objective of this study is to quantify the regional curvatures and area strain based on three-dimensional (3-D) reconstructions of the RV using cardiac magnetic resonance imaging (MRI). Fourteen (14) rTOF patients and nine (9) normal subjects underwent cardiac MRI scan. 3-D RV endocardial surface models were reconstructed from manually delineated contours and correspondence between end-diastole (ED) and end systole (ES) was determined. Regional curvedness (C) and surface area at ED and ES were calculated as well as the area strain. The RV shape and deformation in rTOF patients differed from normal subjects in several respects. Firstly, the curvedness at ED (mean for 13 segments, 0.030 ± 0.0076 vs. 0.029 ± 0.0065 mm(-1); P < 0.05) and ES (mean for 13 segments, 0.040 ± 0.012 vs. 0.034 ± 0.0072 mm(-1); P < 0.001) was decreased by chronic pulmonary regurgitation. Secondly, the surface area increased significantly at ED (mean for 13 segments, 982 ± 192 vs. 1,397 ± 387 mm(2); P < 0.001) and ES (mean for 13 segments, 576 ± 130 vs. 1,012 ± 302 mm(2); P < 0.001). In particular, rTOF patients had significantly larger surface area than that in normal subjects in the free wall but not for the septal wall. Thirdly, area strain was significantly decreased (mean for 13 segments, 56 ± 6 vs. 34 ± 7%; P < 0.0001) in rTOF patients. Fourthly, there were increases in surface area at ED (5,726 ± 969 vs. 6,605 ± 1,122 mm(2); P < 0.05) and ES (4,280 ± 758 vs. 5,569 ± 1,112 mm(2); P < 0.01) and decrease in area strain (29 ± 8 vs. 18 ± 8%; P < 0.001) for RV outflow tract. These findings suggest significant geometric and strain differences between rTOF and normal subjects that may help guide therapeutic treatment.
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Affiliation(s)
- Liang Zhong
- Cardiac Mechanics Engineering and Physiology Unit, National Heart Centre Singapore, Singapore
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Khalafvand SS, Ng EYK, Zhong L. CFD simulation of flow through heart: a perspective review. Comput Methods Biomech Biomed Engin 2011; 14:113-32. [PMID: 21271418 DOI: 10.1080/10255842.2010.493515] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The heart is an organ which pumps blood around the body by contraction of muscular wall. There is a coupled system in the heart containing the motion of wall and the motion of blood fluid; both motions must be computed simultaneously, which make biological computational fluid dynamics (CFD) difficult. The wall of the heart is not rigid and hence proper boundary conditions are essential for CFD modelling. Fluid-wall interaction is very important for real CFD modelling. There are many assumptions for CFD simulation of the heart that make it far from a real model. A realistic fluid-structure interaction modelling the structure by the finite element method and the fluid flow by CFD use more realistic coupling algorithms. This type of method is very powerful to solve the complex properties of the cardiac structure and the sensitive interaction of fluid and structure. The final goal of heart modelling is to simulate the total heart function by integrating cardiac anatomy, electrical activation, mechanics, metabolism and fluid mechanics together, as in the computational framework.
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Affiliation(s)
- S S Khalafvand
- School of Mechanical and Aerospace Engineering, College of Engineering, 50 Nanyang Avenue, Nanyang Technological University, Singapore.
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Maffessanti F, Lang RM, Niel J, Steringer-Mascherbauer R, Caiani EG, Nesser HJ, Mor-Avi V. Three-dimensional analysis of regional left ventricular endocardial curvature from cardiac magnetic resonance images. Magn Reson Imaging 2011; 29:516-24. [DOI: 10.1016/j.mri.2010.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 11/02/2010] [Indexed: 11/26/2022]
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Zhong L, Su Y, Gobeawan L, Sola S, Tan RS, Navia JL, Ghista DN, Chua T, Guccione J, Kassab GS. Impact of surgical ventricular restoration on ventricular shape, wall stress, and function in heart failure patients. Am J Physiol Heart Circ Physiol 2011; 300:H1653-60. [PMID: 21357513 DOI: 10.1152/ajpheart.00021.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Surgical ventricular restoration (SVR) was designed to treat patients with aneurysms or large akinetic walls and dilated ventricles. Yet, crucial aspects essential to the efficacy of this procedure like optimal shape and size of the left ventricle (LV) are still debatable. The objective of this study is to quantify the efficacy of SVR based on LV regional shape in terms of curvedness, wall stress, and ventricular systolic function. A total of 40 patients underwent magnetic resonance imaging (MRI) before and after SVR. Both short-axis and long-axis MRI were used to reconstruct end-diastolic and end-systolic three-dimensional LV geometry. The regional shape in terms of surface curvedness, wall thickness, and wall stress indexes were determined for the entire LV. The infarct, border, and remote zones were defined in terms of end-diastolic wall thickness. The LV global systolic function in terms of global ejection fraction, the ratio between stroke work (SW) and end-diastolic volume (SW/EDV), the maximal rate of change of pressure-normalized stress (dσ*/dt(max)), and the regional function in terms of surface area change were examined. The LV end-diastolic and end-systolic volumes were significantly reduced, and global systolic function was improved in ejection fraction, SW/EDV, and dσ*/dt(max). In addition, the end-diastolic and end-systolic stresses in all zones were reduced. Although there was a slight increase in regional curvedness and surface area change in each zone, the change was not significant. Also, while SVR reduced LV wall stress with increased global LV systolic function, regional LV shape and function did not significantly improve.
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Affiliation(s)
- L Zhong
- Department of Cardiology, National Heart Centre, Singapore.
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