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Wang N, Benemerito I, Sourbron SP, Marzo A. An In Silico Modelling Approach to Predict Hemodynamic Outcomes in Diabetic and Hypertensive Kidney Disease. Ann Biomed Eng 2024:10.1007/s10439-024-03573-2. [PMID: 38969955 DOI: 10.1007/s10439-024-03573-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
Early diagnosis of kidney disease remains an unmet clinical challenge, preventing timely and effective intervention. Diabetes and hypertension are two main causes of kidney disease, can often appear together, and can only be distinguished by invasive biopsy. In this study, we developed a modelling approach to simulate blood velocity, volumetric flow rate, and pressure wave propagation in arterial networks of ageing, diabetic, and hypertensive virtual populations. The model was validated by comparing our predictions for pressure, volumetric flow rate and waveform-derived indexes with in vivo data on ageing populations from the literature. The model simulated the effects of kidney disease, and was calibrated to align quantitatively with in vivo data on diabetic and hypertensive nephropathy from the literature. Our study identified some potential biomarkers extracted from renal blood flow rate and flow pulsatility. For typical patient age groups, resistive index values were 0.69 (SD 0.05) and 0.74 (SD 0.02) in the early and severe stages of diabetic nephropathy, respectively. Similar trends were observed in the same stages of hypertensive nephropathy, with a range from 0.65 (SD 0.07) to 0.73 (SD 0.05), respectively. Mean renal blood flow rate through a single diseased kidney ranged from 329 (SD 40, early) to 317 (SD 38, severe) ml/min in diabetic nephropathy and 443 (SD 54, early) to 388 (SD 47, severe) ml/min in hypertensive nephropathy, showing potential as a biomarker for early diagnosis of kidney disease. This modelling approach demonstrated its potential application in informing biomarker identification and facilitating the setup of clinical trials.
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Affiliation(s)
- Ning Wang
- INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK.
- Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK.
- The University of Sheffield, Room E09, The Pam Liversidge Building, Mappin Street, Sheffield, S13JD, UK.
| | - Ivan Benemerito
- INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK
- Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK
| | - Steven P Sourbron
- INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK
- School of Medicine and Population Health, The University of Sheffield, Sheffield, UK
| | - Alberto Marzo
- INSIGNEO Institute for In Silico Medicine, The University of Sheffield, Sheffield, UK
- Department of Mechanical Engineering, The University of Sheffield, Sheffield, UK
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Zhong P, Lu Z, Li Z, Li T, Lan Q, Liu J, Chen S, Wang Z, Huang Q. Impact of premorbid hypertension and renin-angiotensin-aldosterone system inhibitors on the severity of aneurysmal subarachnoid haemorrhage: a multicentre study. Stroke Vasc Neurol 2024:svn-2023-003052. [PMID: 38889918 DOI: 10.1136/svn-2023-003052] [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: 12/19/2023] [Accepted: 05/28/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Hypertension is widely acknowledged as a significant contributory factor to the heightened risk of intracranial aneurysm rupture. Nevertheless, the impact of hypertension management on the outcomes subsequent to aneurysmal subarachnoid haemorrhage (aSAH), particularly concerning the severity of aSAH, remains an underexplored area. METHODS We conducted a retrospective analysis using data from a prospectively multicentre cohort of 4545 patients with aSAH in China. Premorbid hypertension status and the utilisation of antihypertensive medications prior to admission were set as key exposure factors. The primary outcomes encompassed unfavourable clinical grading scales observed on admission. Employing multivariable logistic regression, we explored the association between premorbid hypertension status, preadmission use of renin-angiotensin-aldosterone system (RAAS) inhibitors and unfavourable clinical grading scales. RESULTS In comparison to patients with normal blood pressure, only uncontrolled hypertension demonstrated a significant and independent association with an elevated risk of poor outcomes on the Hunt-Hess scale (OR=1.799, 95% CI 1.413 to 2.291, p<0.001) and the World Federation of Neurological Surgeons (WFNS) scale (OR=1.721, 95% CI 1.425 to 2.079, p<0.001). Furthermore, the antecedent use of RAAS inhibitors before admission was markedly and independently linked to a diminished risk of adverse outcomes on the Hunt-Hess scale (OR=0.653, 95% CI 0.430 to 0.992, p=0.046) and the WFNS scale (OR=0.656, 95% CI 0.469 to 0.918, p=0.014). CONCLUSIONS Uncontrolled hypertension markedly elevates the risk of adverse clinical outcomes following an aSAH. Conversely, the preadmission utilisation of RAAS inhibitors demonstrates a noteworthy association with a favourable clinical outcome after aSAH.
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Affiliation(s)
- Ping Zhong
- Department of Neurosurgery and Department of Neuroscience, Fujian Key Laboratory of Brain Tumors Diagnosis and Precision Treatment, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
- Department of Neuroscience, Institute of Neurosurgery, School of Medicine, Xiamen University, Xiamen, Fujian, China
- Department of Neurosurgery, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Zhiwen Lu
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhangyu Li
- Department of Neurosurgery, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Tianxiao Li
- Neurovascular Center, Henan Provincial People's Hospital, Zhengzhou, Henan Province, China
| | - Qing Lan
- Department of Neurosurgery, Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Jianmin Liu
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Sifang Chen
- Department of Neurosurgery, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Zhanxiang Wang
- Department of Neurosurgery and Department of Neuroscience, Fujian Key Laboratory of Brain Tumors Diagnosis and Precision Treatment, Xiamen Key Laboratory of Brain Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
- Department of Neuroscience, Institute of Neurosurgery, School of Medicine, Xiamen University, Xiamen, Fujian, China
- Department of Neurosurgery, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Qinghai Huang
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Shanghai, China
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Ramaekers MJFG, van der Vlugt IB, Westenberg JJM, Perinajová R, Lamb HJ, Wildberger JE, Kenjereš S, Schalla S. Flow patterns in ascending aortic aneurysms: Determining the role of hypertension using phase contrast magnetic resonance and computational fluid dynamics. Comput Biol Med 2024; 172:108310. [PMID: 38508054 DOI: 10.1016/j.compbiomed.2024.108310] [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: 10/08/2023] [Revised: 02/22/2024] [Accepted: 03/12/2024] [Indexed: 03/22/2024]
Abstract
Thoracic aortic aneurysm (TAA) is a local dilation of the thoracic aorta. Although universally used, aneurysm diameter alone is a poor predictor of major complications such as rupture. There is a need for better biomarkers for risk assessment that also reflect the aberrant flow patterns found in TAAs. Furthermore, hypertension is often present in TAA patients and may play a role in progression of aneurysm. The exact relation between TAAs and hypertension is poorly understood. This study aims to create a numerical model of hypertension in the aorta by using computational fluid dynamics. First, a normotensive state was simulated in which flow and resistance were kept unaltered. Second, a hypertensive state was modeled in which blood inflow was increased by 30%. Third, a hypertensive state was modeled in which the proximal and peripheral resistances and capacitance parameters from the three-element Windkessel boundary condition were adjusted to mimic an increase in resistance of the rest of the cardiovascular system. One patient with degenerative TAA and one healthy control were successfully simulated at hypertensive states and were extensively analyzed. Furthermore, three additional TAA patients and controls were simulated to validate our method. Hemodynamic variables such as wall shear stress, oscillatory shear index, endothelial cell activation potential (ECAP), vorticity and helicity were studied to gain more insight on the effects of hypertension on flow patterns in TAAs. By comparing a TAA patient and a control at normotensive state at peak-systole, helicity and vorticity were found to be lower in the TAA patient throughout the entire domain. No major changes in flow and flow derived quantities were observed for the TAA patient and control when resistance was increased. When flow rate was increased, regions with high ECAP values were found to reduce in TAA patients in the aneurysm region which could reduce the risk of thrombogenesis. Thus, it may be important to assess cardiac output in patients with TAA.
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Affiliation(s)
- M J F G Ramaekers
- Departments of Cardiology and Radiology and Nuclear Medicine, Maastricht University Medical Center +, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - I B van der Vlugt
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - J J M Westenberg
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - R Perinajová
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands; J.M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands
| | - H J Lamb
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - J E Wildberger
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands; Department of Radiology and Nuclear Medicine, Maastricht University Medical Center +, Maastricht, The Netherlands
| | - S Kenjereš
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands; J.M. Burgerscentrum Research School for Fluid Mechanics, Delft, The Netherlands.
| | - S Schalla
- Departments of Cardiology and Radiology and Nuclear Medicine, Maastricht University Medical Center +, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
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Zhong P, Lu Z, Li Z, Li T, Lan Q, Liu J, Wang Z, Chen S, Huang Q. Effect of Renin-Angiotensin-Aldosterone System Inhibitors on the Rupture Risk Among Hypertensive Patients With Intracranial Aneurysms. Hypertension 2022; 79:1475-1486. [PMID: 35656813 DOI: 10.1161/hypertensionaha.122.18970] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Mounting experimental evidence supports the concept that the RAAS (renin-angiotensin-aldosterone system) is involved in the pathogenesis of intracranial aneurysm rupture. However, whether RAAS inhibitors could reduce the rupture risk of intracranial aneurysms remains unclear. METHODS We performed a chart review of a multicenter, prospectively maintained database of 3044 hypertensive patients with intracranial aneurysms from 20 medical centers in China. The patients were separated into ruptured and unruptured groups. Univariable and multivariable logistical regression analyses were performed to determine the association between the use of RAAS inhibitors and the rupture risk. Sensitivity analyses and subgroup analyses were performed to verify the robustness of the results. RESULTS In multivariable analyses, female sex, passive smoking, uncontrolled, or unmonitored hypertension, use of over 2 antihypertensive medications, RAAS inhibitors use, antihyperglycemic agents use, hyperlipidemia, ischemic stroke, and aneurysmal location were independently associated with the rupture risk. The use of RAAS inhibitors was significantly associated with a reduced rupture risk compared with the use of non-RAAS inhibitors (odds ratio, 0.490 [95% CI, 0.402-0.597]; P=0.000). Compared with the use of non-RAAS inhibitors, the use of ACE (angiotensin-converting enzyme) inhibitors (odds ratio, 0.559 [95% CI, 0.442-0.709]; P=0.000) and use of ARBs (angiotensin receptor blockers; odds ratio, 0.414 [95% CI, 0.315-0.542]; P=0.000) were both significantly associated with a reduced rupture risk. The negative association of the rupture risk with RAAS inhibitors was consistent across 3 analyzed data and the predefined subgroups (including controlled hypertension). CONCLUSIONS The use of RAAS inhibitors was significantly associated with a decreased rupture risk independent of blood pressure control among hypertensive patients with intracranial aneurysms.
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Affiliation(s)
- Ping Zhong
- Department of Neurosurgery (P.Z., Z. Li, S.C.), School of Medicine, Xiamen University, China.,BE and Phase I Clinical Trial Center (P.Z.), School of Medicine, Xiamen University, China
| | - Zhiwen Lu
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Shanghai, China (Z. Lu, J.L., Q.H)
| | - Zhangyu Li
- Department of Neurosurgery (P.Z., Z. Li, S.C.), School of Medicine, Xiamen University, China
| | - Tianxiao Li
- Neurovascular Center, Henan Provincial People's Hospital, Zhengzhou, China (T.L.)
| | - Qing Lan
- Department of Neurosurgery, Second Affiliated Hospital of Soochow University, Suzhou, China (Q.L.)
| | - Jianmin Liu
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Shanghai, China (Z. Lu, J.L., Q.H)
| | - Zhanxiang Wang
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center (Z.W.), School of Medicine, Xiamen University, China.,The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University and Department of Neuroscience, Institute of Neurosurgery (Z.W.), School of Medicine, Xiamen University, China
| | - Sifang Chen
- Department of Neurosurgery (P.Z., Z. Li, S.C.), School of Medicine, Xiamen University, China
| | - Qinghai Huang
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Shanghai, China (Z. Lu, J.L., Q.H)
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Zhong P, Lu Z, Li T, Lan Q, Liu J, Wang Z, Chen S, Huang Q. Association Between Regular Blood Pressure Monitoring and the Risk of Intracranial Aneurysm Rupture: a Multicenter Retrospective Study with Propensity Score Matching. Transl Stroke Res 2022; 13:983-994. [PMID: 35314955 DOI: 10.1007/s12975-022-01006-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/24/2022] [Accepted: 03/10/2022] [Indexed: 12/20/2022]
Abstract
Although hypertension is a known risk factor for intracranial aneurysm rupture, the benefit of the management of blood pressure in reducing the rupture risk of intracranial aneurysms remains largely unknown, especially for regular blood pressure monitoring. We conducted a retrospective analysis of a prospectively maintained database of 3965 patients with saccular intracranial aneurysms from 20 medical centers in China. The patients were divided into the non-hypertensive group and hypertensive group. Propensity score matching was applied to identify a cohort of patients with similar baseline characteristics. Univariable and multivariable logistic regression analyses were performed to determine the association between intracranial aneurysm rupture and the management of blood pressure. After matching, hypertension was significantly associated with an increased rupture risk of intracranial aneurysms (OR = 2.559, 95%CI = 2.161-3.030, P = 0.000). For the management of blood pressure, controlled hypertension (OR = 1.803, 95%CI = 1.409-2.307, P = 0.000), uncontrolled hypertension (OR = 2.178, 95%CI = 1.756-2.700, P = 0.000), and hypertension without regular blood pressure monitoring (OR = 5.000, 95%CI = 3.823-6.540, P = 0.000) were all significantly associated with a higher rupture risk compared with the absence of hypertension. Moreover, hypertension without regular blood pressure monitoring was associated with a higher rupture risk compared with either controlled hypertension (OR = 3.807, 95%CI = 2.687-5.395, P = 0.000) or hypertension with regular blood pressure monitoring (including controlled and uncontrolled hypertension) (OR = 2.893, 95%CI = 2.319-3.609, P = 0.000). The absence of regular blood pressure monitoring was significantly associated with an increased risk of intracranial aneurysm rupture, emphasizing the importance of implementation of regular blood pressure monitoring in hypertensive patients with intracranial aneurysms.
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Affiliation(s)
- Ping Zhong
- BE and Phase I Clinical Trial Center, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Zhiwen Lu
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Changhai Road 168, Shanghai, 200433, China
| | - Tianxiao Li
- Neurovascular Center, Henan Provincial People's Hospital, Zhengzhou, China
| | - Qing Lan
- Department of Neurosurgery, Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Jianmin Liu
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Changhai Road 168, Shanghai, 200433, China
| | - Zhanxiang Wang
- Department of Neurosurgery, Xiamen Key Laboratory of Brain Center, the First Affiliated Hospital of Xiamen University, Xiamen, China.,Department of Neuroscience, Institute of Neurosurgery, School of Medicine, Xiamen University, Xiamen, China
| | - Sifang Chen
- Department of Neurosurgery, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, No. 55 Zhenhai Road, Xiamen, 361003, Fujian, China.
| | - Qinghai Huang
- Neurovascular Center, Changhai Hospital, Second Military Medical University, Changhai Road 168, Shanghai, 200433, China.
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Shimano K, Serigano S, Ikeda N, Yuchi T, Shiratori S, Nagano H. Understanding of boundary conditions imposed at multiple outlets in computational haemodynamic analysis of cerebral aneurysm. ACTA ACUST UNITED AC 2019. [DOI: 10.17106/jbr.33.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kenjiro Shimano
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Shota Serigano
- Graduate School of Integrative Science and Engineering, Tokyo City University
| | - Naoki Ikeda
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Tomoki Yuchi
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Suguru Shiratori
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Hideaki Nagano
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
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Zhang H, Li L, Cheng C, Sun X. Clinical value of homodynamic numerical simulation applied in the treatment of cerebral aneurysm. Exp Ther Med 2017; 14:5401-5404. [PMID: 29163674 PMCID: PMC5684832 DOI: 10.3892/etm.2017.5189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/12/2017] [Indexed: 11/06/2022] Open
Abstract
Our objective was to evaluate the clinical value of numerical simulation in diagnosing cerebral aneurysm based on the analysis of numerical simulation of hemodynamic model. The experimental method used was the numerical model of cerebral aneurysm hemodynamic, and the numerical value of blood flow at each point was analyzed. The results showed that, the wall shear stress (WSS) value on the top of CA1 was significantly lower than that of the top (P<0.05), the WSS value of each point on the CA2 tumor was significantly lower than that of tumor neck (P<0.05); the pressure value on the tumor top and tumor neck between CA1 and CA2 had no significant difference (P>0.05); the unsteady index of shear (UIS) value at the points of 20 had distinctly changed, the wave range was 0.6-1.5; the unsteady index of pressure value of every point was significantly lower than UIS value, the wave range was 0.25-0.40. In conclusion, the application of cerebral aneurysm hemodynamic research can help doctors to diagnose cerebral aneurysm more precisely and to grasp the opportunity of treatment during the formulating of the treatment strategies.
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Affiliation(s)
- Hailin Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Li Li
- School of Clinical Medicine, Gansu University of Chinese Medicine, Lanzhou, Gansu 730030, P.R. China
| | - Chongjie Cheng
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Xiaochuan Sun
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
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VALENCIA ALVARO, TORRES FRANCISCO. EFFECTS OF HYPERTENSION AND PRESSURE GRADIENT IN A HUMAN CEREBRAL ANEURYSM USING FLUID STRUCTURE INTERACTION SIMULATIONS. J MECH MED BIOL 2017. [DOI: 10.1142/s021951941750018x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fluid–structure interaction (FSI) simulations were carried out in a human cerebral aneurysm model with the objective of quantifying the effects of hypertension and pressure gradient on the behavior of fluid and solid mechanics. Six FSI simulations were conducted using a hyperelastic Mooney–Rivlin model. Important differences in wall shear stress (WSS), wall displacements, and effective von Mises stress are reported. The hypertension increases wall stress and displacements in the aneurysm region; however, the effects of hypertension on the hemodynamics in the aneurysm region were small. The pressure gradient affects the WSS in the aneurysm and also the displacement and wall stress on the aneurysm. Maximum wall stress with hypertension in the range of rupture strength was found.
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Affiliation(s)
- ALVARO VALENCIA
- Department of Mechanical Engineering, Universidad de Chile, Beauchef 851, Santiago 8370456, Chile
| | - FRANCISCO TORRES
- Department of Mechanical Engineering, Universidad de Chile, Beauchef 851, Santiago 8370456, Chile
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Cebral JR, Duan X, Chung BJ, Putman C, Aziz K, Robertson AM. Wall Mechanical Properties and Hemodynamics of Unruptured Intracranial Aneurysms. AJNR Am J Neuroradiol 2015; 36:1695-703. [PMID: 26228891 PMCID: PMC4890156 DOI: 10.3174/ajnr.a4358] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/30/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Aneurysm progression and rupture is thought to be governed by progressive degradation and weakening of the wall in response to abnormal hemodynamics. Our goal was to investigate the relationship between the intra-aneurysmal hemodynamic conditions and wall mechanical properties in human aneurysms. MATERIALS AND METHODS A total of 8 unruptured aneurysms were analyzed. Computational fluid dynamics models were constructed from preoperative 3D rotational angiography images. The aneurysms were clipped, and the domes were resected and mechanically tested to failure with a uniaxial testing system under multiphoton microscopy. Linear regression analysis was performed to explore possible correlations between hemodynamic quantities and the failure characteristics and stiffness of the wall. RESULTS The ultimate strain was correlated negatively to aneurysm inflow rate (P = .021), mean velocity (P = .025), and mean wall shear stress (P = .039). It was also correlated negatively to inflow concentration, oscillatory shear index, and measures of the complexity and instability of the flow; however, these trends did not reach statistical significance. The wall stiffness at high strains was correlated positively to inflow rate (P = .014), mean velocity (P = .008), inflow concentration (P = .04), flow instability (P = .006), flow complexity (P = .019), wall shear stress (P = .002), and oscillatory shear index (P = .004). CONCLUSIONS In a study of 8 unruptured intracranial aneurysms, ultimate strain was correlated negatively with aneurysm inflow rate, mean velocity, and mean wall shear stress. Wall stiffness was correlated positively with aneurysm inflow rate, mean velocity, wall shear stress, flow complexity and stability, and oscillatory shear index. These trends and the impact of hemodynamics on wall structure and mechanical properties should be investigated further in larger studies.
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Affiliation(s)
- J R Cebral
- From the Department of Bioengineering (J.R.C., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - X Duan
- Department of Mechanical Engineering and Material Science (X.D., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - B J Chung
- From the Department of Bioengineering (J.R.C., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - C Putman
- Interventional Neuroradiology (C.P.), Inova Fairfax Hospital, Falls Church, Virginia
| | - K Aziz
- Neurosurgery (K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - A M Robertson
- Department of Mechanical Engineering and Material Science (X.D., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
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