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Alkhatib F, Wittek A, Zwick BF, Bourantas GC, Miller K. Computation for biomechanical analysis of aortic aneurysms: the importance of computational grid. Comput Methods Biomech Biomed Engin 2024; 27:994-1010. [PMID: 37264784 DOI: 10.1080/10255842.2023.2218521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/22/2023] [Indexed: 06/03/2023]
Abstract
Aortic wall stress is the most common variable of interest in abdominal aortic aneurysm (AAA) rupture risk assessment. Computation of such stress has been dominated by finite element analysis. However, the effects of finite element (FE) formulation, element quality, and methods of FE mesh construction on the efficiency, robustness, and accuracy of such computation have attracted little attention. In this study, we fill this knowledge gap by comparing the results of the calculated aortic wall stress for ten AAA patients using tetrahedral and hexahedral meshes when varying the FE formulation (displacement-based and hybrid), FE shape functions, spatial integration scheme, and number of elements through the wall thickness.
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Affiliation(s)
- Farah Alkhatib
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - Adam Wittek
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - Benjamin F Zwick
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - George C Bourantas
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
- Department of Agriculture, University of Patras, Rio, Greece
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
- Harvard Medical School, Boston, MA, USA
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Berggren CC, Jiang D, Jack Wang YF, Bergquist JA, Rupp LC, Liu Z, MacLeod RS, Narayan A, Timmins LH. Influence of material parameter variability on the predicted coronary artery biomechanical environment via uncertainty quantification. Biomech Model Mechanobiol 2024; 23:927-940. [PMID: 38361087 PMCID: PMC11102342 DOI: 10.1007/s10237-023-01814-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 12/30/2023] [Indexed: 02/17/2024]
Abstract
Central to the clinical adoption of patient-specific modeling strategies is demonstrating that simulation results are reliable and safe. Indeed, simulation frameworks must be robust to uncertainty in model input(s), and levels of confidence should accompany results. In this study, we applied a coupled uncertainty quantification-finite element (FE) framework to understand the impact of uncertainty in vascular material properties on variability in predicted stresses. Univariate probability distributions were fit to material parameters derived from layer-specific mechanical behavior testing of human coronary tissue. Parameters were assumed to be probabilistically independent, allowing for efficient parameter ensemble sampling. In an idealized coronary artery geometry, a forward FE model for each parameter ensemble was created to predict tissue stresses under physiologic loading. An emulator was constructed within the UncertainSCI software using polynomial chaos techniques, and statistics and sensitivities were directly computed. Results demonstrated that material parameter uncertainty propagates to variability in predicted stresses across the vessel wall, with the largest dispersions in stress within the adventitial layer. Variability in stress was most sensitive to uncertainties in the anisotropic component of the strain energy function. Moreover, unary and binary interactions within the adventitial layer were the main contributors to stress variance, and the leading factor in stress variability was uncertainty in the stress-like material parameter that describes the contribution of the embedded fibers to the overall artery stiffness. Results from a patient-specific coronary model confirmed many of these findings. Collectively, these data highlight the impact of material property variation on uncertainty in predicted artery stresses and present a pipeline to explore and characterize forward model uncertainty in computational biomechanics.
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Affiliation(s)
- Caleb C Berggren
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - David Jiang
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Y F Jack Wang
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Jake A Bergquist
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
- Nora Eccles Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
| | - Lindsay C Rupp
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
- Nora Eccles Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
| | - Zexin Liu
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
| | - Rob S MacLeod
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
- Nora Eccles Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
| | - Akil Narayan
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
| | - Lucas H Timmins
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA.
- School of Engineering Medicine, Texas A&M University, 1020 Holcombe Blvd., Houston, TX, USA.
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA.
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Siika A, Talvitie M, Lindquist Liljeqvist M, Bogdanovic M, Gasser TC, Hultgren R, Roy J. Peak wall rupture index is associated with risk of rupture of abdominal aortic aneurysms, independent of size and sex. Br J Surg 2024; 111:znae125. [PMID: 38782730 PMCID: PMC11116082 DOI: 10.1093/bjs/znae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 04/10/2024] [Accepted: 04/27/2024] [Indexed: 05/25/2024]
Abstract
BACKGROUND Information on the predictive determinants of abdominal aortic aneurysm rupture from CT angiography are scarce. The aim of this study was to investigate biomechanical parameters in abdominal aortic aneurysms and their association with risk of subsequent rupture. METHODS In this retrospective study, the digital radiological archive was searched for 363 patients with ruptured abdominal aortic aneurysms. All patients who underwent at least one CT angiography examination before aneurysm rupture were included. CT angiography results were analysed to determine maximum aneurysm diameter, aneurysm volume, and biomechanical parameters (peak wall stress and peak wall rupture index). In the primary survival analysis, patients with abdominal aortic aneurysms less than 70 mm were considered. Sensitivity analyses including control patients and abdominal aortic aneurysms of all sizes were performed. RESULTS A total of 67 patients who underwent 109 CT angiography examinations before aneurysm rupture were identified. The majority were men (47, 70%) and the median age at the time of CTA examination was 77 (71-83) years. The median maximum aneurysm diameter was 56 (interquartile range 46-65) mm and the median time to rupture was 2.13 (interquartile range 0.64-4.72) years. In univariable analysis, maximum aneurysm diameter, aneurysm volume, peak wall stress, and peak wall rupture index were all associated with risk of rupture. Women had an increased HR for rupture when adjusted for maximum aneurysm diameter or aneurysm volume (HR 2.16, 95% c.i. 1.23 to 3.78 (P = 0.007) and HR 1.92, 95% c.i. 1.06 to 3.50 (P = 0.033) respectively). In multivariable analysis, the peak wall rupture index was associated with risk of rupture. The HR for peak wall rupture index was 1.05 (95% c.i. 1.03 to 1.08) per % (P < 0.001) when adjusted for maximum aneurysm diameter and 1.05 (95% c.i. 1.02 to 1.08) per % (P < 0.001) when adjusted for aneurysm volume. CONCLUSION Biomechanical factors appear to be important in the prediction of abdominal aortic aneurysm rupture. Women are at increased risk of rupture when adjustments are made for maximum aneurysm diameter alone.
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Affiliation(s)
- Antti Siika
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Mareia Talvitie
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - Moritz Lindquist Liljeqvist
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - Marko Bogdanovic
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - T Christian Gasser
- KTH Solid Mechanics, Department of Engineering Mechanics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden
- Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Rebecka Hultgren
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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Derwich W, Schönborn M, Blase C, Wittek A, Oikonomou K, Böckler D, Erhart P. Correlation of four-dimensional ultrasound strain analysis with computed tomography angiography wall stress simulations in abdominal aortic aneurysms. JVS Vasc Sci 2024; 5:100199. [PMID: 38633883 PMCID: PMC11022090 DOI: 10.1016/j.jvssci.2024.100199] [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: 12/12/2023] [Accepted: 03/09/2024] [Indexed: 04/19/2024] Open
Abstract
Objective Biomechanical modeling of infrarenal aortic aneurysms seeks to predict ruptures in advance, thereby reducing aneurysm-related deaths. As individual methods focusing on strain and stress analysis lack adequate discretization power, this study aims to explore multifactorial characterization for progressive aneurysmal degeneration. The study's objective is to compare stress- and strain-related parameters in infrarenal aortic aneurysms. Methods Twenty-two patients with abdominal aortic aneurysms (AAAs) (mean maximum diameter, 53.2 ± 7.2 mm) were included in the exploratory study, examined by computed tomography angiography (CTA) and three-dimensional real-time speckle tracking ultrasound (4D-US). The conformity of aneurysm anatomy in 4D-US and CTA was determined with the mean point-to-point distance (MPPD). CTA was employed for each AAA to characterize stress-related indices using the semi-automated A4-clinics RE software. Five segmentations from one 4D-US examination were fused into one averaged model for strain analysis using MATLAB and the Abaqus solver. Results The mean MPPD between the adjacent points of the 4D-US and CTA-derived geometry was 1.8 ± 0.4 mm. The interclass correlation coefficients for all raters and all measurements for the maximum AAA diameter in 2D, 4D ultrasound, and CTA indicate moderate to good reliability (interclass correlation coefficient1 0.69 with 95% confidence interval [CI], 0.49-0.84; P < .001). The peak wall stress (PWS) correlates fairly with the maximum AAA diameter in 2D-US (r = 0.54; P < .01) and 4D-US (r = 0.53; P < .05) and moderately strongly with the maximum exterior AAA diameter (r = 0.63; P < .01). The peak wall rupture risk index shows a strong correlation with the PWS (ρ > 0.9; P < .001) and is influenced by anatomical parameters with equal strength. Isolated observation of the intraluminal thrombus does not provide significant information in the determination of PWS. The maximum AAA diameter in 2D-US shows a fair negative correlation with the mean circumferential, longitudinal and in-plane shear strain (ρ = -0.46; r = -0.45; ρ = -0.47; P < .05 for all). The circumferential strain ratio as an indicator of wall motion heterogeneity increases with the aneurysm diameter (r = 0.47; P < .05). The direct comparison of wall strain and wall stress indices shows no quantitative correlation. Conclusions The strain and stress analyses provide independent biomechanical information of AAAs. At the current stage of development, the two methods are considered complementary and may optimize a more patient-specific rupture risk prediction in the future.
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Affiliation(s)
- Wojciech Derwich
- Vascular and Endovascular Surgery, Department of Cardiac and Vascular Surgery, University Hospital Frankfurt Goethe University, Frankfurt/Main, Germany
| | - Manuel Schönborn
- Personalized Biomedical Engineering Lab, Frankfurt University of Applied Sciences, Frankfurt/Main, Germany
| | - Christopher Blase
- Personalized Biomedical Engineering Lab, Frankfurt University of Applied Sciences, Frankfurt/Main, Germany
| | - Andreas Wittek
- Personalized Biomedical Engineering Lab, Frankfurt University of Applied Sciences, Frankfurt/Main, Germany
| | - Kyriakos Oikonomou
- Vascular and Endovascular Surgery, Department of Cardiac and Vascular Surgery, University Hospital Frankfurt Goethe University, Frankfurt/Main, Germany
| | - Dittmar Böckler
- Department of Vascular and Endovascular Surgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Philipp Erhart
- Department of Vascular and Endovascular Surgery, Heidelberg University Hospital, Heidelberg, Germany
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Turčanová M, Fischer J, Hermanová M, Bednařík Z, Skácel P, Burša J. Biaxial stretch can overcome discrepancy between global and local orientations of wavy collagen fibres. J Biomech 2023; 161:111868. [PMID: 37976938 DOI: 10.1016/j.jbiomech.2023.111868] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 09/20/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023]
Abstract
Most frequently used structure-based constitutive models of arterial wall apply assumptions on two symmetric helical (and dispersed) fibre families which, however, are not well supported with histological findings where two collagen fibre families are seldom found. Moreover, bimodal distributions of fibre directions may originate also from their waviness combined with ignoring differences between local and global fibre orientations. In contrast, if the model parameters are identified without histological information on collagen fibre directions, the resulting mean angles of both fibre families are close to ±45°, which contradicts nearly all histologic findings. The presented study exploited automated polarized light microscopy for detection of collagen fibre directions in porcine aorta under different biaxial extensions and approximated the resulting histograms with unimodal and bimodal von Mises distributions. Their comparison showed dominantly circumferential orientation of collagen fibres. Their concentration parameter for unimodal distributions increased with circumferential load, no matter if acting uniaxially or equibiaxially. For bimodal distributions, the angle between both dominant fibre directions (chosen as measure of fibre alignment) decreased similarly for both uniaxial and equibiaxial loads. These results indicate the existence of a single family of wavy circumferential collagen fibres in all layers of the aortic wall. Bimodal distributions of fibre directions presented sometimes in literature may come rather from waviness of circumferentially arranged fibres than from two symmetric families of helical fibres. To obtain a final evidence, the fibre orientation should be analysed together with their waviness.
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Affiliation(s)
- Michaela Turčanová
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic.
| | - Jiří Fischer
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic
| | - Markéta Hermanová
- 1st Department of Pathology, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Pekařská 664/53, 656 91 Brno, Czech Republic
| | - Zdeněk Bednařík
- 1st Department of Pathology, St. Anne's University Hospital Brno and Faculty of Medicine, Masaryk University, Pekařská 664/53, 656 91 Brno, Czech Republic
| | - Pavel Skácel
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic
| | - Jiří Burša
- Brno University of Technology, Faculty of Mechanical Engineering, Institute of Solid Mechanics, Mechatronics and Biomechanics, Technická 2896/2, Brno 616 69, Czech Republic
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Hof A, Guthoff H, Ahdab M, Landerer M, Schäkel J, Niehues J, Schorscher M, Zimmermann O, Winkels H, von Stein P, Geißen S, Baldus S, Adam M, Mollenhauer M, Mehrkens D. Vascular Ultrasound for In Vivo Assessment of Arterial Pathologies in a Murine Model of Atherosclerosis and Aortic Aneurysm. Int J Mol Sci 2023; 24:15261. [PMID: 37894941 PMCID: PMC10607567 DOI: 10.3390/ijms242015261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Vascular diseases like atherosclerosis and abdominal aortic aneurysm (AAA) are common pathologies in the western world, promoting various potentially fatal conditions. Here, we evaluate high-resolution (HR) ultrasound in mouse models of atherosclerosis and AAA as a useful tool for noninvasive monitoring of early vascular changes in vivo. We used Apolipoprotein E-deficient (ApoE-/-) mice as an atherosclerosis model and induced AAA development by the implementation of Angiotensin II-releasing osmotic minipumps. HR ultrasound of the carotid artery or the abdominal aorta was performed to monitor vascular remodeling in vivo. Images were analyzed by speckle tracking algorithms and correlated to histological analyses and subsequent automated collagen quantification. Consistent changes were observed via ultrasound in both models: Global radial strain (GRS) was notably reduced in the AAA model (23.8 ± 2.8% vs. 12.5 ± 2.5%, p = 0.01) and in the atherosclerotic mice (20.6 ± 1.3% vs. 15.8 ± 0.9%, p = 0.02). In mice with AAA, vessel distensibility was significantly reduced, whereas intima-media thickness was increased in atherosclerotic mice. The area and collagen content of the tunica media were increased in diseased arteries of both models as measured by automated image analysis of Picrosirius Red-stained aortic sections. Correlation analysis revealed a strong correlation of multiple parameters, predicting early vascular damage in HR ultrasound and histological examinations. In conclusion, our findings underscore the potential of HR ultrasound in effectively tracing early alterations in arterial wall properties in murine models of atherosclerosis and AAA.
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Affiliation(s)
- Alexander Hof
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Henning Guthoff
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Maysam Ahdab
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
| | - Max Landerer
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
| | - Jasper Schäkel
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Jana Niehues
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
| | - Maximilian Schorscher
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Oscar Zimmermann
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Holger Winkels
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Philipp von Stein
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
| | - Simon Geißen
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Stephan Baldus
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Matti Adam
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Martin Mollenhauer
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
| | - Dennis Mehrkens
- Department for Experimental Cardiology, Faculty of Medicine, University of Cologne, Clinic III for Internal Medicine, University Hospital Cologne, 50937 Cologne, Germany; (A.H.); (M.A.); (M.L.); (J.S.); (J.N.); (M.S.); (O.Z.); (H.W.); (P.v.S.); (S.G.); (S.B.); (M.A.); (M.M.)
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and Faculty of Mathematics and Natural Sciences, University of Cologne, 50937 Cologne, Germany
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7
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Wang X, Carpenter HJ, Ghayesh MH, Kotousov A, Zander AC, Amabili M, Psaltis PJ. A review on the biomechanical behaviour of the aorta. J Mech Behav Biomed Mater 2023; 144:105922. [PMID: 37320894 DOI: 10.1016/j.jmbbm.2023.105922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 06/17/2023]
Abstract
Large aortic aneurysm and acute and chronic aortic dissection are pathologies of the aorta requiring surgery. Recent advances in medical intervention have improved patient outcomes; however, a clear understanding of the mechanisms leading to aortic failure and, hence, a better understanding of failure risk, is still missing. Biomechanical analysis of the aorta could provide insights into the development and progression of aortic abnormalities, giving clinicians a powerful tool in risk stratification. The complexity of the aortic system presents significant challenges for a biomechanical study and requires various approaches to analyse the aorta. To address this, here we present a holistic review of the biomechanical studies of the aorta by categorising articles into four broad approaches, namely theoretical, in vivo, experimental and combined investigations. Experimental studies that focus on identifying mechanical properties of the aortic tissue are also included. By reviewing the literature and discussing drawbacks, limitations and future challenges in each area, we hope to present a more complete picture of the state-of-the-art of aortic biomechanics to stimulate research on critical topics. Combining experimental modalities and computational approaches could lead to more comprehensive results in risk prediction for the aortic system.
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Affiliation(s)
- Xiaochen Wang
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Harry J Carpenter
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Mergen H Ghayesh
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Andrei Kotousov
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Anthony C Zander
- School of Electrical and Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Marco Amabili
- Department of Mechanical Engineering, McGill University, Montreal H3A 0C3, Canada
| | - Peter J Psaltis
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Cardiology, Central Adelaide Local Health Network, Adelaide, South Australia 5000, Australia; Vascular Research Centre, Heart Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, South Australia 5000, Australia
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8
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Bracco MI, Broda M, Lorenzen US, Florkow MC, Somphone O, Avril S, Biancolini ME, Rouet L. Fast strain mapping in abdominal aortic aneurysm wall reveals heterogeneous patterns. Front Physiol 2023; 14:1163204. [PMID: 37362444 PMCID: PMC10285457 DOI: 10.3389/fphys.2023.1163204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/17/2023] [Indexed: 06/28/2023] Open
Abstract
Abdominal aortic aneurysm patients are regularly monitored to assess aneurysm development and risk of rupture. A preventive surgical procedure is recommended when the maximum aortic antero-posterior diameter, periodically assessed on two-dimensional abdominal ultrasound scans, reaches 5.5 mm. Although the maximum diameter criterion has limited ability to predict aneurysm rupture, no clinically relevant tool that could complement the current guidelines has emerged so far. In vivo cyclic strains in the aneurysm wall are related to the wall response to blood pressure pulse, and therefore, they can be linked to wall mechanical properties, which in turn contribute to determining the risk of rupture. This work aimed to enable biomechanical estimations in the aneurysm wall by providing a fast and semi-automatic method to post-process dynamic clinical ultrasound sequences and by mapping the cross-sectional strains on the B-mode image. Specifically, the Sparse Demons algorithm was employed to track the wall motion throughout multiple cardiac cycles. Then, the cyclic strains were mapped by means of radial basis function interpolation and differentiation. We applied our method to two-dimensional sequences from eight patients. The automatic part of the analysis took under 1.5 min per cardiac cycle. The tracking method was validated against simulated ultrasound sequences, and a maximum root mean square error of 0.22 mm was found. The strain was calculated both with our method and with the established finite-element method, and a very good agreement was found, with mean differences of one order of magnitude smaller than the image spatial resolution. Most patients exhibited a strain pattern that suggests interaction with the spine. To conclude, our method is a promising tool for investigating abdominal aortic aneurysm wall biomechanics as it can provide a fast and accurate measurement of the cyclic wall strains from clinical ultrasound sequences.
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Affiliation(s)
- Marta Irene Bracco
- Mines Saint-Étienne, University Jean Monnet, INSERM, Sainbiose, Saint-Étienne, France
- Philips Research Paris, Suresnes, France
| | - Magdalena Broda
- Department of Vascular Surgery, Rigshospitalet, Copenhagen, Denmark
| | | | | | | | - Stephane Avril
- Mines Saint-Étienne, University Jean Monnet, INSERM, Sainbiose, Saint-Étienne, France
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9
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Gasser TC, Miller C, Polzer S, Roy J. A quarter of a century biomechanical rupture risk assessment of abdominal aortic aneurysms. Achievements, clinical relevance, and ongoing developments. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3587. [PMID: 35347895 DOI: 10.1002/cnm.3587] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/28/2022] [Accepted: 03/03/2022] [Indexed: 05/12/2023]
Abstract
Abdominal aortic aneurysm (AAA) disease, the local enlargement of the infrarenal aorta, is a serious condition that causes many deaths, especially in men exceeding 65 years of age. Over the past quarter of a century, computational biomechanical models have been developed towards the assessment of AAA risk of rupture, technology that is now on the verge of being integrated within the clinical decision-making process. The modeling of AAA requires a holistic understanding of the clinical problem, in order to set appropriate modeling assumptions and to draw sound conclusions from the simulation results. In this article we summarize and critically discuss the proposed modeling approaches and report the outcome of clinical validation studies for a number of biomechanics-based rupture risk indices. Whilst most of the aspects concerning computational mechanics have already been settled, it is the exploration of the failure properties of the AAA wall and the acquisition of robust input data for simulations that has the greatest potential for the further improvement of this technology.
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Affiliation(s)
- T Christian Gasser
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
- Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Christopher Miller
- Department of Engineering Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Stanislav Polzer
- Department of Applied Mechanics, VSB-Technical University of Ostrava, Ostrava-Poruba, Czech Republic
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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10
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Dynamic Loading-A New Marker for Abdominal Aneurysm Growth? MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59020404. [PMID: 36837605 PMCID: PMC9967562 DOI: 10.3390/medicina59020404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/07/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023]
Abstract
The growing possibilities of non-invasive heart rate and blood pressure measurement with mobile devices allow vital data to be continuously collected and used to assess patients' health status. When it comes to the risk assessment of abdominal aortic aneurysms (AAA), the continuous tracking of blood pressure and heart rate could enable a more patient-specific approach. The use of a load function and an energy function, with continuous blood pressure, heart rate, and aneurysm stiffness as input parameters, can quantify dynamic load on AAA. We hypothesise that these load functions correlate with aneurysm growth and outline a possible study procedure in which the hypothesis could be tested for validity. Subsequently, uncertainty quantification of input quantities and derived quantities is performed.
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11
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Biomechanical Rupture Risk Assessment in Management of Patients with Abdominal Aortic Aneurysm in COVID-19 Pandemic. Diagnostics (Basel) 2022; 13:diagnostics13010132. [PMID: 36611424 PMCID: PMC9818825 DOI: 10.3390/diagnostics13010132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/18/2022] [Accepted: 12/27/2022] [Indexed: 01/04/2023] Open
Abstract
Background: The acute phase of the COVID-19 pandemic requires a redefinition of healthcare system to increase the number of available intensive care units for COVID-19 patients. This leads to the postponement of elective surgeries including the treatment of abdominal aortic aneurysm (AAA). The probabilistic rupture risk index (PRRI) recently showed its advantage over the diameter criterion in AAA rupture risk assessment. Its major improvement is in increased specificity and yet has the same sensitivity as the maximal diameter criterion. The objective of this study was to test the clinical applicability of the PRRI method in a quasi-prospective patient cohort study. Methods: Nineteen patients (fourteen males, five females) with intact AAA who were postponed due to COVID-19 pandemic were included in this study. The PRRI was calculated at the baseline via finite element method models. If a case was diagnosed as high risk (PRRI > 3%), the patient was offered priority in AAA intervention. Cases were followed until 10 September 2021 and a number of false positive and false negative cases were recorded. Results: Each case was assessed within 3 days. Priority in intervention was offered to two patients with high PRRI. There were four false positive cases and no false negative cases classified by PRRI. In three cases, the follow-up was very short to reach any conclusion. Conclusions: Integrating PRRI into clinical workflow is possible. Longitudinal validation of PRRI did not fail and may significantly decrease the false positive rate in AAA treatment.
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12
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O'Rourke D, Surman TL, Abrahams JM, Edwards J, Reynolds KJ. Predicting rupture locations of ascending aortic aneurysms using CT-based finite element models. J Biomech 2022; 145:111351. [PMID: 36334320 DOI: 10.1016/j.jbiomech.2022.111351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 09/05/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022]
Abstract
Accurate rupture risk assessment of ascending aortic aneurysms is important for reducing aneurysm-related mortality. More recently, computational models have been shown to better predict rupture risk than diameter-based measurements. However, it remains unclear whether finite element (FE) models of the ascending aorta can predict rupture location, and over what timeframe those predictions are reliable. The aim of this study was to evaluate FE models of the ascending aorta generated from computed tomography (CT) scans in predicting rupture location. Pre- and post-rupture CT scans were obtained of 12 patients who underwent emergency surgical repair for ascending aorta rupture with varying time intervals between scans (20 days - 6 years). A rigid iterative closest point (ICP) registration was used to overlay post-rupture aortic geometries with pre-rupture FE models and directly compare predicted regions of high equivalent strain with actual rupture. The FE model predicted the rupture location in the 5 patients with the shortest time intervals between the pre- and post-rupture scans (20 days - 2 years, 3 months). However, rupture location was not predicted in the 4/5 patients with greater than 3 years between scans. Achieving a physiological equivalent strain distribution in the FE model was highly dependent on the resolution of the pre-rupture scan and whether contrast agent was present. The results suggest there may be a time interval beyond which FE predictions of rupture location may not be reliable. The results in this study may help clinical validation of FE models of ascending aortic aneurysms predicting rupture risk.
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Affiliation(s)
- Dermot O'Rourke
- Medical Device Research Institute, College of Science and Engineering, Flinders University. Australia.
| | - Timothy L Surman
- D'Arcy Sutherland Cardiothoracic Surgical Unit, Royal Adelaide Hospital, Adelaide, Australia
| | - John M Abrahams
- Centre for Orthopaedic and Trauma Research, The University of Adelaide, Adelaide, Australia
| | - James Edwards
- D'Arcy Sutherland Cardiothoracic Surgical Unit, Royal Adelaide Hospital, Adelaide, Australia
| | - Karen J Reynolds
- Medical Device Research Institute, College of Science and Engineering, Flinders University. Australia
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13
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Arbănași EM, Mureșan AV, Coșarcă CM, Arbănași EM, Niculescu R, Voidăzan ST, Ivănescu AD, Hălmaciu I, Filep RC, Mărginean L, Suzuki S, Chirilă TV, Kaller R, Russu E. Computed Tomography Angiography Markers and Intraluminal Thrombus Morphology as Predictors of Abdominal Aortic Aneurysm Rupture. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:15961. [PMID: 36498041 PMCID: PMC9741090 DOI: 10.3390/ijerph192315961] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/26/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Background: Abdominal aortic aneurysm (AAA) is a complex vascular disease characterized by progressive and irreversible local dilatation of the aortic wall. Currently, the indication for repair is linked to the transverse diameter of the abdominal aorta, using computed tomography angiography imagery, which is one of the most used markers for aneurysmal growth. This study aims to verify the predictive role of imaging markers and underlying risk factors in AAA rupture. Methods: The present study was designed as an observational, analytical, retrospective cohort study and included 220 patients over 18 years of age with a diagnosis of AAA, confirmed by computed tomography angiography (CTA), admitted to Vascular Surgery Clinic of Mures County Emergency Hospital in Targu Mures, Romania, between January 2018 and September 2022. Results: Patients with a ruptured AAA had higher incidences of AH (p = 0.006), IHD (p = 0.001), AF (p < 0.0001), and MI (p < 0.0001), and higher incidences of all risk factors (tobacco (p = 0.001), obesity (p = 0.02), and dyslipidemia (p < 0.0001)). Multivariate analysis showed that a high baseline value of all imaging ratios markers was a strong independent predictor of AAA rupture (for all p < 0.0001). Moreover, a higher baseline value of DAmax (OR:3.91; p = 0.001), SAmax (OR:7.21; p < 0.001), and SLumenmax (OR:34.61; p < 0.001), as well as lower baseline values of DArenal (OR:7.09; p < 0.001), DACT (OR:12.71; p < 0.001), DAfemoral (OR:2.56; p = 0.005), SArenal (OR:4.56; p < 0.001), SACT (OR:3.81; p < 0.001), and SThrombusmax (OR:5.27; p < 0.001) were independent predictors of AAA rupture. In addition, AH (OR:3.33; p = 0.02), MI (OR:3.06; p = 0.002), and PAD (OR:2.71; p = 0.004) were all independent predictors of AAA rupture. In contrast, higher baseline values of SAmax/Lumenmax (OR:0.13; p < 0.001) and ezetimibe (OR:0.45; p = 0.03) were protective factors against AAA rupture. Conclusions: According to our findings, a higher baseline value of all imaging markers ratios at CTA strongly predicts AAA rupture and AH, MI, and PAD highly predicted the risk of rupture in AAA patients. Furthermore, the diameter of the abdominal aorta at different levels has better accuracy and a higher predictive role of rupture than the maximal diameter of AAA.
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Affiliation(s)
- Emil Marian Arbănași
- Doctoral School of Medicine and Pharmacy, George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, 540142 Targu Mures, Romania
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
| | - Adrian Vasile Mureșan
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
- Department of Surgery, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Cătălin Mircea Coșarcă
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
| | - Eliza Mihaela Arbănași
- Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Raluca Niculescu
- Department of Pathophysiology, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Septimiu Toader Voidăzan
- Department of Epidemiology, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Adrian Dumitru Ivănescu
- Department of Anatomy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Ioana Hălmaciu
- Department of Anatomy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Rareș Cristian Filep
- Department of Radiology, Mures County Emergency Hospital, 540136 Targu Mures, Romania
| | - Lucian Mărginean
- Department of Radiology, Mures County Emergency Hospital, 540136 Targu Mures, Romania
| | - Shuko Suzuki
- Queensland Eye Institute, South Brisbane, QLD 4101, Australia
| | - Traian V. Chirilă
- Queensland Eye Institute, South Brisbane, QLD 4101, Australia
- School of Chemistry & Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
- Australian Institute of Bioengineering & Nanotechnology (AIBN), University of Queensland, St. Lucia, QLD 4072, Australia
- Faculty of Medicine, University of Queensland, Herston, QLD 4006, Australia
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia
- Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
| | - Réka Kaller
- Doctoral School of Medicine and Pharmacy, George Emil Palade University of Medicine, Pharmacy, Sciences and Technology of Targu Mures, 540142 Targu Mures, Romania
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
| | - Eliza Russu
- Clinic of Vascular Surgery, Mures County Emergency Hospital, 540136 Targu Mures, Romania
- Department of Surgery, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540139 Targu Mures, Romania
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14
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Zhou J, Li J, Qin S, Liu J, Lin Z, Xie J, Zhang Z, Chen R. High-resolution cerebral blood flow simulation with a domain decomposition method and verified by the TCD measurement. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 224:107004. [PMID: 35841853 DOI: 10.1016/j.cmpb.2022.107004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 06/24/2022] [Accepted: 07/03/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND An efficient and accurate blood flow simulation can be useful for understanding many vascular diseases. Accurately resolving the blood flow velocity based on patient-specific geometries and model parameters is still a major challenge because of complex geomerty and turbulence issues. In addition, obtaining results in a short amount of computing time is important so that the simulation can be used in the clinical environment. In this work, we present a parallel scalable method for the patient-specific blood flow simulation with focuses on its parallel performance study and clinical verification. METHODS We adopt a fully implicit unstructured finite element method for a patient-specific simulation of blood flow in a full precerebral artery. The 3D artery is constructed from MRI images, and a parallel Newton-Krylov method preconditioned with a two-level domain decomposition method is adopted to solve the large nonlinear system discretized from the time-dependent 3D Navier-Stokes equations in the artery with an integral outlet boundary condition. The simulated results are verified using the clinical data measured by transcranial Doppler ultrasound, and the parallel performance of the algorithm is studied on a supercomputer. RESULTS The simulated velocity matches the clinical measured data well. Other simulated blood flow parameters, such as pressure and wall shear stress, are within reasonable ranges. The results show that the parallel algorithm scales up to 2160 processors with a 49% parallel efficiency for solving a problem with over 20 million unstructured elements on a supercomputer. For a standard cerebral blood flow simulation case with approximately 4 million finite elements, the calculation of one cardiac cycle can be finished within one hour with 1000 processors. CONCLUSION The proposed method is able to perform high-resolution 3D blood flow simulations in a patient-specific full precerebral artery within an acceptable time, and the simulated results are comparable with the clinical measured data, which demonstrates its high potential for clinical applications.
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Affiliation(s)
- Jie Zhou
- School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha, China
| | - Jing Li
- School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha, China
| | - Shanlin Qin
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
| | - Jia Liu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zeng Lin
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jian Xie
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Zhijun Zhang
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Rongliang Chen
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, China.
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15
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Wittek A, Alkhatib F, Vitásek R, Polzer S, Miller K. On stress in abdominal aortic aneurysm: Linear versus non-linear analysis and aneurysm rupture risk. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3554. [PMID: 34806314 DOI: 10.1002/cnm.3554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
We present comprehensive biomechanical analyses of abdominal aortic aneurysms (AAA) for 43 patients. We compare stress magnitudes and stress distributions within arterial walls of abdominal aortic aneurysms (AAA) obtained using two simulation and modelling methods: (a) Fully automated and computationally very efficient linear method embedded in the software platform Biomechanics based Prediction of Aneurysm Rupture Risk (BioPARR), freely available from https://bioparr.mech.uwa.edu.au/; (b) More complex and much more computationally demanding Non-Linear Iterative Stress Analysis (Non-LISA) that uses a non-linear inverse iterative approach and strongly non-linear material model. Both methods predicted localised high stress zones with over 90% of AAA model volume fraction subjected to stress below 20% of the 99th percentile maximum principal stress. However, for the non-linear iterative method, the peak maximum principal stress (and 99th percentile maximum principal stress) was higher and the stress magnitude in the low stress area lower than for the automated linear method embedded in BioPARR. Differences between the stress distributions obtained using the two methods tended to be particularly pronounced in the areas where the AAA curvature was large. Performance of the selected characteristic features of the stress fields (we used 99th percentile maximum principal stress) obtained using BioPARR and Non-LISA in distinguishing between the AAAs that would rupture and remain intact was for practical purposes the same for both methods.
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Affiliation(s)
- Adam Wittek
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - Farah Alkhatib
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
| | - Radek Vitásek
- Department of Applied Mechanics, VSB Technical University of Ostrava, Ostrava, Czech Republic
| | - Stanislav Polzer
- Department of Applied Mechanics, VSB Technical University of Ostrava, Ostrava, Czech Republic
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Western Australia, Australia
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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16
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Avril S, Gee MW, Hemmler A, Rugonyi S. Patient-specific computational modeling of endovascular aneurysm repair: State of the art and future directions. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3529. [PMID: 34490740 DOI: 10.1002/cnm.3529] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Endovascular aortic repair (EVAR) has become the preferred intervention option for aortic aneurysms and dissections. This is because EVAR is much less invasive than the alternative open surgery repair. While in-hospital mortality rates are smaller for EVAR than open repair (1%-2% vs. 3%-5%), the early benefits of EVAR are lost after 3 years due to larger rates of complications in the EVAR group. Clinicians follow instructions for use (IFU) when possible, but are left with personal experience on how to best proceed and what choices to make with respect to stent-graft (SG) model choice, sizing, procedural options, and their implications on long-term outcomes. Computational modeling of SG deployment in EVAR and tissue remodeling after intervention offers an alternative way of testing SG designs in silico, in a personalized way before intervention, to ultimately select the strategies leading to better outcomes. Further, computational modeling can be used in the optimal design of SGs in cases of complex geometries. In this review, we address some of the difficulties and successes associated with computational modeling of EVAR procedures. There is still work to be done in all areas of EVAR in silico modeling, including model validation, before models can be applied in the clinic, but much progress has already been made. Critical to clinical implementation are current efforts focusing on developing fast algorithms that can achieve (near) real-time solutions, as well as ways of dealing with inherent uncertainties related to patient aortic wall degradation on an individualized basis. We are optimistic that EVAR modeling in the clinic will soon become a reality to help clinicians optimize EVAR interventions and ultimately reduce EVAR-associated complications.
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Affiliation(s)
- Stéphane Avril
- Mines Saint-Étienne, Univ Lyon, Univ Jean Monnet, INSERM, Saint-Étienne, France
| | - Michael W Gee
- Mechanics & High Performance Computing Group, Department of Mechanical Engineering, Technical University of Munich, Garching, Germany
| | - André Hemmler
- Mechanics & High Performance Computing Group, Department of Mechanical Engineering, Technical University of Munich, Garching, Germany
| | - Sandra Rugonyi
- Biomedical Engineering Department, Oregon Health & Science University, Portland, Oregon, USA
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17
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Busch A, Bleichert S, Ibrahim N, Wortmann M, Eckstein HH, Brostjan C, Wagenhäuser MU, Goergen CJ, Maegdefessel L. Translating mouse models of abdominal aortic aneurysm to the translational needs of vascular surgery. JVS Vasc Sci 2021; 2:219-234. [PMID: 34778850 PMCID: PMC8577080 DOI: 10.1016/j.jvssci.2021.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/04/2021] [Indexed: 01/03/2023] Open
Abstract
Introduction Abdominal aortic aneurysm (AAA) is a condition that has considerable socioeconomic impact and an eventual rupture is associated with high mortality and morbidity. Despite decades of research, surgical repair remains the treatment of choice and no medical therapy is currently available. Animal models and, in particular, murine models, of AAA are a vital tool for experimental in vivo research. However, each of the different models has individual limitations and provide only partial mimicry of human disease. This narrative review addresses the translational potential of the available mouse models, highlighting unanswered questions from a clinical perspective. It is based on a thorough presentation of the available literature and more than a decade of personal experience, with most of the available models in experimental and translational AAA research. Results From all the models published, only the four inducible models, namely the angiotensin II model (AngII), the porcine pancreatic elastase perfusion model (PPE), the external periadventitial elastase application (ePPE), and the CaCl2 model have been widely used by different independent research groups. Although the angiotensin II model provides features of dissection and aneurysm formation, the PPE model shows reliable features of human AAA, especially beyond day 7 after induction, but remains technically challenging. The translational value of ePPE as a model and the combination with β-aminopropionitrile to induce rupture and intraluminal thrombus formation is promising, but warrants further mechanistic insights. Finally, the external CaCl2 application is known to produce inflammatory vascular wall thickening. Unmet translational research questions include the origin of AAA development, monitoring aneurysm growth, gender issues, and novel surgical therapies as well as novel nonsurgical therapies. Conclusion New imaging techniques, experimental therapeutic alternatives, and endovascular treatment options provide a plethora of research topics to strengthen the individual features of currently available mouse models, creating the possibility of shedding new light on translational research questions.
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Affiliation(s)
- Albert Busch
- Department for Vascular and Endovascular Surgery, Technical University Munich, Munich, Germany.,Deutsches Zentrum für Herz-Kreislaufforschung (DZHK), Berlin, Germany
| | - Sonja Bleichert
- Division of Vascular Surgery and Surgical Research Laboratories, Department of Surgery, Medical University of Vienna, Vienna General Hospital, Vienna, Austria
| | - Nahla Ibrahim
- Division of Vascular Surgery and Surgical Research Laboratories, Department of Surgery, Medical University of Vienna, Vienna General Hospital, Vienna, Austria
| | - Markus Wortmann
- Department of Vascular and Endovascular Surgery, Universitaetsklinik Heidelberg, Heidelberg, Germany
| | - Hans-Henning Eckstein
- Department for Vascular and Endovascular Surgery, Technical University Munich, Munich, Germany
| | - Christine Brostjan
- Division of Vascular Surgery and Surgical Research Laboratories, Department of Surgery, Medical University of Vienna, Vienna General Hospital, Vienna, Austria
| | - Markus U Wagenhäuser
- Department of Vascular and Endovascular Surgery, Heinrich-Heine-University Medical Center Düsseldorf, Düsseldorf, Germany
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Ind
| | - Lars Maegdefessel
- Department for Vascular and Endovascular Surgery, Technical University Munich, Munich, Germany.,Deutsches Zentrum für Herz-Kreislaufforschung (DZHK), Berlin, Germany
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18
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Lindquist Liljeqvist M, Bogdanovic M, Siika A, Gasser TC, Hultgren R, Roy J. Geometric and biomechanical modeling aided by machine learning improves the prediction of growth and rupture of small abdominal aortic aneurysms. Sci Rep 2021; 11:18040. [PMID: 34508118 PMCID: PMC8433325 DOI: 10.1038/s41598-021-96512-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/02/2021] [Indexed: 12/17/2022] Open
Abstract
It remains difficult to predict when which patients with abdominal aortic aneurysm (AAA) will require surgery. The aim was to study the accuracy of geometric and biomechanical analysis of small AAAs to predict reaching the threshold for surgery, diameter growth rate and rupture or symptomatic aneurysm. 189 patients with AAAs of diameters 40-50 mm were included, 161 had undergone two CTAs. Geometric and biomechanical variables were used in prediction modelling. Classifications were evaluated with area under receiver operating characteristic curve (AUC) and regressions with correlation between observed and predicted growth rates. Compared with the baseline clinical diameter, geometric-biomechanical analysis improved prediction of reaching surgical threshold within four years (AUC 0.80 vs 0.85, p = 0.031) and prediction of diameter growth rate (r = 0.17 vs r = 0.38, p = 0.0031), mainly due to the addition of semiautomatic diameter measurements. There was a trend towards increased precision of volume growth rate prediction (r = 0.37 vs r = 0.45, p = 0.081). Lumen diameter and biomechanical indices were the only variables that could predict future rupture or symptomatic AAA (AUCs 0.65-0.67). Enhanced precision of diameter measurements improves the prediction of reaching the surgical threshold and diameter growth rate, while lumen diameter and biomechanical analysis predicts rupture or symptomatic AAA.
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Affiliation(s)
- Moritz Lindquist Liljeqvist
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden.
| | - Marko Bogdanovic
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Antti Siika
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - T Christian Gasser
- Department of Engineering Mechanics, Royal Institute of Technology, Stockholm, Sweden
| | - Rebecka Hultgren
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
| | - Joy Roy
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Vascular Surgery, Karolinska University Hospital, Stockholm, Sweden
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19
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Liu M, Liang L, Ismail Y, Dong H, Lou X, Iannucci G, Chen EP, Leshnower BG, Elefteriades JA, Sun W. Computation of a probabilistic and anisotropic failure metric on the aortic wall using a machine learning-based surrogate model. Comput Biol Med 2021; 137:104794. [PMID: 34482196 DOI: 10.1016/j.compbiomed.2021.104794] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/20/2021] [Accepted: 08/21/2021] [Indexed: 01/15/2023]
Abstract
Scalar-valued failure metrics are commonly used to assess the risk of aortic aneurysm rupture and dissection, which occurs under hypertensive blood pressures brought on by extreme emotional or physical stress. To compute failure metrics under an elevated blood pressure, a classical patient-specific computer model consists of multiple computation steps involving inverse and forward analyses. These classical procedures may be impractical for time-sensitive clinical applications that require prompt feedback to clinicians. In this study, we developed a machine learning-based surrogate model to directly predict a probabilistic and anisotropic failure metric, namely failure probability (FP), on the aortic wall using aorta geometries at the systolic and diastolic phases. Ascending thoracic aortic aneurysm (ATAA) geometries of 60 patients were obtained from their CT scans, and biaxial mechanical testing data of ATAA tissues from 79 patients were collected. Finite element simulations were used to generate datasets for training, validation, and testing of the ML-surrogate model. The testing results demonstrated that the ML-surrogate can compute the maximum FP failure metric, with 0.42% normalized mean absolute error, in 1 s. To compare the performance of the ML-predicted probabilistic FP metric with other isotropic or deterministic metrics, a numerical case study was performed using synthetic "baseline" data. Our results showed that the probabilistic FP metric had more discriminative power than the deterministic Tsai-Hill metric, isotropic maximum principal stress, and aortic diameter criterion.
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Affiliation(s)
- Minliang Liu
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Liang Liang
- Department of Computer Science, University of Miami, Coral Gables, FL, USA
| | - Yasmeen Ismail
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Hai Dong
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Xiaoying Lou
- Emory University School of Medicine, Atlanta, GA, USA
| | - Glen Iannucci
- Emory University School of Medicine, Atlanta, GA, USA
| | - Edward P Chen
- Emory University School of Medicine, Atlanta, GA, USA
| | | | | | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
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Rengarajan B, Patnaik SS, Finol EA. A Predictive Analysis of Wall Stress in Abdominal Aortic Aneurysms Using a Neural Network Model. J Biomech Eng 2021; 143:1115051. [PMID: 34318314 DOI: 10.1115/1.4051905] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Indexed: 11/08/2022]
Abstract
Rupture risk assessment of abdominal aortic aneurysms (AAAs) by means of quantifying wall stress is a common biomechanical strategy. However, the clinical translation of this approach has been greatly limited due to the complexity associated with the computational tools required for its implementation. Thus, being able to estimate wall stress using nonbiomechanical markers that can be quantified as a direct outcome of clinical image segmentation would be advantageous in improving the potential implementation of said strategy. In the present work, we investigated the use of geometric indices to predict patient-specific AAA wall stress by means of a novel neural network (NN) modeling approach. We conducted a retrospective review of existing clinical images of two patient groups: 98 asymptomatic and 50 symptomatic AAAs. The images were subject to a protocol consisting of image segmentation, processing, volume meshing, finite element modeling, and geometry quantification, from which 53 geometric indices and the spatially averaged wall stress (SAWS) were calculated. SAWS estimated from finite element analysis was considered the gold standard for the predictions. We developed feed-forward NN models composed of an input layer, two dense layers, and an output layer using Keras, a deep learning library in python. The NN models were trained, tested, and validated independently for both AAA groups using all geometric indices, as well as a reduced set of indices resulting from a variable reduction procedure. We compared the performance of the NN models with two standard machine learning algorithms (MARS: multivariate adaptive regression splines and GAM: generalized additive model) and a linear regression model (GLM: generalized linear model). With the reduced sets of indices, the NN-based approach exhibited the highest mean goodness-of-fit (for the symptomatic group 0.71 and for the asymptomatic group 0.79) and lowest mean relative error (17% for both groups). In contrast, MARS yielded a mean goodness-of-fit of 0.59 for the symptomatic group and 0.77 for the asymptomatic group, with relative errors of 17% for the symptomatic group and 22% for the asymptomatic group. GAM had a mean goodness-of-fit of 0.70 for the symptomatic group and 0.80 for the asymptomatic group, with relative errors of 16% for the symptomatic group and 20% for the asymptomatic group. GLM did not perform as well as the other algorithms, with a mean goodness-of-fit of 0.53 for the symptomatic group and 0.70 for the asymptomatic group, with relative errors of 19% for the symptomatic group and 23% for the asymptomatic group. Nevertheless, the NN models required a reduced set of 15 and 13 geometric indices to predict SAWS for the symptomatic and asymptomatic AAA groups, respectively. This was in contrast to the reduced set of nine and eight geometric indices required to predict SAWS with the MARS and GAM algorithms for each AAA group, respectively. The use of NN modeling represents a promising alternative methodology for the estimation of AAA wall stress using geometric indices as surrogates, in lieu of finite element modeling. The performance metrics of NN models are expected to improve with significantly larger group sizes, given the suitability of NN modeling for "big data" applications.
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Affiliation(s)
- Balaji Rengarajan
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249
| | - Sourav S Patnaik
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249; Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080
| | - Ender A Finol
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249
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21
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Qin S, Wu B, Liu J, Shiu WS, Yan Z, Chen R, Cai XC. Efficient parallel simulation of hemodynamics in patient-specific abdominal aorta with aneurysm. Comput Biol Med 2021; 136:104652. [PMID: 34329862 DOI: 10.1016/j.compbiomed.2021.104652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/30/2021] [Accepted: 07/13/2021] [Indexed: 10/20/2022]
Abstract
Surgical planning for aortic aneurysm repair is a difficult task. In addition to the morphological features obtained from medical imaging, alternative features obtained with computational modeling may provide additional useful information. Though numerical studies are noninvasive, they are often time-consuming, especially when we need to study and compare multiple repair scenarios, because of the high computational complexity. In this paper, we present a highly parallel algorithm for the numerical simulation of unsteady blood flows in the patient-specific abdominal aorta before and after the aneurysmic repair. We model the blood flow with the unsteady incompressible Navier-Stokes equations with different outlet boundary conditions, and solve the discretized system with a highly scalable domain decomposition method. With this approach, a high resolution simulation of a full-size adult aorta can be obtained in less than an hour, instead of days with older methods and software. In addition, we show that the parallel efficiency of the proposed method is near 70% on a parallel computer with 2, 880 processor cores.
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Affiliation(s)
- Shanlin Qin
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Bokai Wu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jia Liu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Wen-Shin Shiu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhengzheng Yan
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Rongliang Chen
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; Shenzhen Key Laboratory for Exascale Engineering and Scientific Computing, Shenzhen, China.
| | - Xiao-Chuan Cai
- Department of Mathematics, University of Macau, Macau, China.
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22
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Polzer S, Kracík J, Novotný T, Kubíček L, Staffa R, Raghavan ML. Methodology for Estimation of Annual Risk of Rupture for Abdominal Aortic Aneurysm. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 200:105916. [PMID: 33503510 DOI: 10.1016/j.cmpb.2020.105916] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Estimating patient specific annual risk of rupture of abdominal aortic aneurysm (AAA) is currently based only on population. More accurate knowledge based on patient specific data would allow surgical treatment of only those AAAs with significant risk of rupture. This would be beneficial for both patients and health care system. METHODS A methodology for estimating annual risk of rupture (EARR) of abdominal aortic aneurysms (AAA) that utilizes Bayesian statistics, mechanics and patient-specific blood pressure monitoring data is proposed. EARR estimation takes into consideration, peak wall stress in AAA computed by patient-specific finite element modeling, the probability distributions of wall thickness, wall strength, systolic blood pressure and the period of time that the patient is known to have already survived with the intact AAA. Initial testing of proposed approach was performed on fifteen patients with intact AAA (mean maximal diameter 51mm±8mm). They were equipped with a pressure holter and their blood pressure was recorded over 24 hours. Then, we calculated EARR values for four possible scenarios - without considering any days of survival prior identification of AAA at computed tomography scans (EARR_0), considering past survival of 30 (EARR_30), 90 (EARR_90) and 180 days (EARR_180). Finally, effect of patient-specific blood pressure variability was analyzed. RESULTS Consideration of past survival does indeed significantly improve predictions of future risk: EARR_30 (1.04%± 0.87%), EARR_90 (0.67%± 0.56%) and EARR_180 (0.47%± 0.39%) which are unrealistically high otherwise (EARR_0 5.02%± 5.24%). Finally, EARR values were observed to vary by an order as a consequence of blood pressure variability and by factor of two as a consequence of neglected growth. CONCLUSIONS Methodology for computing annual risk of rupture of AAA was developed for the first time. Sensitivity analyses showed respecting patient specific blood pressure is important factor and should be included in the AAA rupture risk assessment. Obtained EARR values were generally low and in good agreement with confirmed survival time of investigated patients so proposed method should be further clinically validated.
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Affiliation(s)
- Stanislav Polzer
- Department of Applied Mechanics, VSB-Technical University of Ostrava, 17.listopadu 2172/15, Ostrava-Poruba, 708 33, Czech Republic.
| | - Jan Kracík
- Department of Applied Mathematics, VSB-Technical University of Ostrava, 17.listopadu 2172/15, Ostrava-Poruba, 708 33, Czech Republic
| | - Tomáš Novotný
- 2nd Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Luboš Kubíček
- 2nd Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Robert Staffa
- 2nd Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Madhavan L Raghavan
- Department of Biomedical Engineering, University of Iowa, 5605 Seamans Center, Iowa City, IA, 52242, USA
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23
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Estimating aortic thoracic aneurysm rupture risk using tension-strain data in physiological pressure range: an in vitro study. Biomech Model Mechanobiol 2021; 20:683-699. [PMID: 33389275 DOI: 10.1007/s10237-020-01410-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 12/02/2020] [Indexed: 12/17/2022]
Abstract
Previous studies have shown that the rupture properties of an ascending thoracic aortic aneurysm (ATAA) are strongly correlated with the pre-rupture response features. In this work, we present a two-step machine learning method to predict where the rupture is likely to occur in ATAA and what safety reserve the structure may have. The study was carried out using ATAA specimens from 15 patients who underwent surgical intervention. Through inflation test, full-field deformation data and post-rupture images were collected, from which the wall tension and surface strain distributions were computed. The tension-strain data in the pressure range of 9-18 kPa were fitted to a third-order polynomial to characterize the response properties. It is hypothesized that the region where rupture is prone to initiate is associated with a high level of tension buildup. A machine learning method is devised to predict the peak risk region. The predicted regions were found to match the actual rupture sites in 13 samples out of the total 15. In the second step, another machine learning model is utilized to predict the tissue's rupture strength in the peak risk region. Results suggest that the ATAA rupture risk can be reasonably predicted using tension-strain response in the physiological range. This may open a pathway for evaluating the ATAA rupture propensity using information of in vivo response.
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24
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Bruder L, Pelisek J, Eckstein HH, Gee MW. Biomechanical rupture risk assessment of abdominal aortic aneurysms using clinical data: A patient-specific, probabilistic framework and comparative case-control study. PLoS One 2020; 15:e0242097. [PMID: 33211767 PMCID: PMC7676745 DOI: 10.1371/journal.pone.0242097] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/26/2020] [Indexed: 11/18/2022] Open
Abstract
We present a data-informed, highly personalized, probabilistic approach for the quantification of abdominal aortic aneurysm (AAA) rupture risk. Our novel framework builds upon a comprehensive database of tensile test results that were carried out on 305 AAA tissue samples from 139 patients, as well as corresponding non-invasively and clinically accessible patient-specific data. Based on this, a multivariate regression model is created to obtain a probabilistic description of personalized vessel wall properties associated with a prospective AAA patient. We formulate a probabilistic rupture risk index that consistently incorporates the available statistical information and generalizes existing approaches. For the efficient evaluation of this index, a flexible Kriging-based surrogate model with an active training process is proposed. In a case-control study, the methodology is applied on a total of 36 retrospective, diameter matched asymptomatic (group 1, n = 18) and known symptomatic/ruptured (group 2, n = 18) cohort of AAA patients. Finally, we show its efficacy to discriminate between the two groups and demonstrate competitive performance in comparison to existing deterministic and probabilistic biomechanical indices.
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Affiliation(s)
- Lukas Bruder
- Mechanics & High Performance Computing Group, Technical University of Munich, Garching, Germany
| | - Jaroslav Pelisek
- Department of Vascular Surgery, University Hospital Zurich, Zurich, Switzerland
- Clinic for Vascular and Endovascular Surgery, Technical University of Munich, Munich, Germany
| | - Hans-Henning Eckstein
- Clinic for Vascular and Endovascular Surgery, Technical University of Munich, Munich, Germany
| | - Michael W. Gee
- Mechanics & High Performance Computing Group, Technical University of Munich, Garching, Germany
- * E-mail:
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25
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Failure properties of abdominal aortic aneurysm tissue are orientation dependent. J Mech Behav Biomed Mater 2020; 114:104181. [PMID: 33153925 DOI: 10.1016/j.jmbbm.2020.104181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 08/12/2020] [Accepted: 10/23/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Biomechanical rupture risk assessment of abdominal aortic aneurysm (AAA) requires information about failure properties of aneurysmal tissue. There are large differences between reported values. Among others, studies vary in using either axially or circumferentially oriented samples. This study investigates the effect of sample orientation on failure properties. METHODS Aneurysmal tissues from 45 patients (11 females) were harvested during open AAA repair, cut into uniaxial samples (90) and tested mechanically within 3 h. If possible, the samples were cut in both axial (49 samples) and circumferential (41 samples) directions. Wall thickness, First Piola-Kirchhoff strength Pult and ultimate tension Tult were recorded. Influence of sample orientation and other clinical parameters were investigated using non parametric tests. RESULTS Medians of Pult (values 1100 kPa for circumferential vs. 715 kPa for axial direction, p < 10-4) and Tult (17.4 N/cm in circumferential vs. 11.2 N/cm in axial direction, p < 10-4) were significantly higher in circumferential direction. For paired data, the median of difference was 411 kPa (p < 10-3) in Pult and 7.4 N/cm (p < 10-4) in Tult in favor of circumferential direction. CONCLUSIONS In this first study of anisotropy in AAA wall failure properties using paired comparisons, the strength in circumferential orientation was found to be higher than in axial orientation.
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26
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Boyd AJ. Biomechanical prediction of abdominal aortic aneurysm rupture potential. J Vasc Surg 2020; 71:627. [PMID: 32040432 DOI: 10.1016/j.jvs.2019.03.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 03/26/2019] [Indexed: 11/25/2022]
Affiliation(s)
- April J Boyd
- Department of Vascular Surgery, University of Manitoba, Winnipeg, Manitoba, Canada
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Elbatarny M, Chung JCY, Ouzounian M. Commentary: Curating the culprits: Moving closer to personalized aortic surgery. J Thorac Cardiovasc Surg 2020; 160:906-907. [PMID: 32475498 DOI: 10.1016/j.jtcvs.2020.04.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/04/2020] [Accepted: 04/07/2020] [Indexed: 10/24/2022]
Affiliation(s)
- Malak Elbatarny
- Division of Cardiovascular Surgery, Department of Surgery, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Jennifer C Y Chung
- Division of Cardiovascular Surgery, Department of Surgery, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Maral Ouzounian
- Division of Cardiovascular Surgery, Department of Surgery, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.
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28
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Commentary: Do not "futz" with Laplace. J Thorac Cardiovasc Surg 2020; 162:1463-1466. [PMID: 32448689 DOI: 10.1016/j.jtcvs.2020.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 11/20/2022]
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