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Zimmermann J, Bäumler K, Loecher M, Cork TE, Marsden AL, Ennis DB, Fleischmann D. Hemodynamic effects of entry and exit tear size in aortic dissection evaluated with in vitro magnetic resonance imaging and fluid-structure interaction simulation. Sci Rep 2023; 13:22557. [PMID: 38110526 PMCID: PMC10728172 DOI: 10.1038/s41598-023-49942-0] [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: 01/05/2023] [Accepted: 12/13/2023] [Indexed: 12/20/2023] Open
Abstract
Understanding the complex interplay between morphologic and hemodynamic features in aortic dissection is critical for risk stratification and for the development of individualized therapy. This work evaluates the effects of entry and exit tear size on the hemodynamics in type B aortic dissection by comparing fluid-structure interaction (FSI) simulations with in vitro 4D-flow magnetic resonance imaging (MRI). A baseline patient-specific 3D-printed model and two variants with modified tear size (smaller entry tear, smaller exit tear) were embedded into a flow- and pressure-controlled setup to perform MRI as well as 12-point catheter-based pressure measurements. The same models defined the wall and fluid domains for FSI simulations, for which boundary conditions were matched with measured data. Results showed exceptionally well matched complex flow patterns between 4D-flow MRI and FSI simulations. Compared to the baseline model, false lumen flow volume decreased with either a smaller entry tear (- 17.8 and - 18.5%, for FSI simulation and 4D-flow MRI, respectively) or smaller exit tear (- 16.0 and - 17.3%). True to false lumen pressure difference (initially 11.0 and 7.9 mmHg, for FSI simulation and catheter-based pressure measurements, respectively) increased with a smaller entry tear (28.9 and 14.6 mmHg), and became negative with a smaller exit tear (- 20.6 and - 13.2 mmHg). This work establishes quantitative and qualitative effects of entry or exit tear size on hemodynamics in aortic dissection, with particularly notable impact observed on FL pressurization. FSI simulations demonstrate acceptable qualitative and quantitative agreement with flow imaging, supporting its deployment in clinical studies.
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Affiliation(s)
| | - Kathrin Bäumler
- Department of Radiology, Stanford University, Stanford, CA, USA.
| | - Michael Loecher
- Department of Radiology, Stanford University, Stanford, CA, USA
- Division of Radiology, Veterans Affairs Health Care System, Palo Alto, CA, USA
| | - Tyler E Cork
- Department of Radiology, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Alison L Marsden
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Pediatrics, Stanford University, Stanford, CA, USA
| | - Daniel B Ennis
- Department of Radiology, Stanford University, Stanford, CA, USA
- Division of Radiology, Veterans Affairs Health Care System, Palo Alto, CA, USA
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Jafarinia A, Melito GM, Müller TS, Rolf-Pissarczyk M, Holzapfel GA, Brenn G, Ellermann K, Hochrainer T. Morphological parameters affecting false lumen thrombosis following type B aortic dissection: a systematic study based on simulations of idealized models. Biomech Model Mechanobiol 2023; 22:885-904. [PMID: 36630014 PMCID: PMC10167197 DOI: 10.1007/s10237-023-01687-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 01/02/2023] [Indexed: 01/12/2023]
Abstract
Type B aortic dissection (TBAD) carries a high risk of complications, particularly with a partially thrombosed or patent false lumen (FL). Therefore, uncovering the risk factors leading to FL thrombosis is crucial to identify high-risk patients. Although studies have shown that morphological parameters of the dissected aorta are related to FL thrombosis, often conflicting results have been reported. We show that recent models of thrombus evolution in combination with sensitivity analysis methods can provide valuable insights into how combinations of morphological parameters affect the prospect of FL thrombosis. Based on clinical data, an idealized geometry of a TBAD is generated and parameterized. After implementing the thrombus model in computational fluid dynamics simulations, a global sensitivity analysis for selected morphological parameters is performed. We then introduce dimensionless morphological parameters to scale the results to individual patients. The sensitivity analysis demonstrates that the most sensitive parameters influencing FL thrombosis are the FL diameter and the size and location of intimal tears. A higher risk of partial thrombosis is observed when the FL diameter is larger than the true lumen diameter. Reducing the ratio of the distal to proximal tear size increases the risk of FL patency. In summary, these parameters play a dominant role in classifying morphologies into patent, partially thrombosed, and fully thrombosed FL. In this study, we point out the predictive role of morphological parameters for FL thrombosis in TBAD and show that the results are in good agreement with available clinical studies.
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Affiliation(s)
- Alireza Jafarinia
- Institute of Strength of Materials, Graz University of Technology, Graz, Austria.
| | - Gian Marco Melito
- Institute of Mechanics, Graz University of Technology, Graz, Austria.
| | - Thomas Stephan Müller
- Institute of Fluid Mechanics and Heat Transfer, Graz University of Technology, Graz, Austria
| | | | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria.,Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Günter Brenn
- Institute of Fluid Mechanics and Heat Transfer, Graz University of Technology, Graz, Austria
| | - Katrin Ellermann
- Institute of Mechanics, Graz University of Technology, Graz, Austria
| | - Thomas Hochrainer
- Institute of Strength of Materials, Graz University of Technology, Graz, Austria
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