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Zeugin T, Coulter FB, Gülan U, Studart AR, Holzner M. In vitro investigation of the blood flow downstream of a 3D-printed aortic valve. Sci Rep 2024; 14:1572. [PMID: 38238358 PMCID: PMC10796383 DOI: 10.1038/s41598-024-51676-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/08/2024] [Indexed: 01/22/2024] Open
Abstract
The hemodynamics in the aorta as well as the durability of aortic valve prostheses vary greatly between different types of devices. Although placement and sizing of surgical aortic valve prostheses are excellent, the valve geometry of common devices cannot be customized to fit the patient's anatomy perfectly. Similarly, transcatheter aortic valve implantation (TAVI) devices are not customizable and may be orientated unfavorably during implantation. Imperfect fit of an aortic valve prosthesis may result in suboptimal performance and in some cases the need for additional surgery. Leveraging the advent of precision, multi-material 3D-printing, a bioinspired silicone aortic valve was developed. The manufacturing technique makes it fully customizable and significantly cheaper to develop and produce than common prostheses. In this study, we assess the hemodynamic performance of such a 3D-printed aortic valve and compare it to two TAVI devices as well as to a severely stenosed valve. We investigate the blood flow distal to the valve in an anatomically accurate, compliant aorta model via three-dimensional particle tracking velocimetry measurements. Our results demonstrate that the 3D-printed aortic valve induces flow patterns and topology compatible with the TAVI valves and showing similarity to healthy aortic blood flow. Compared to the stenosis, the 3D-printed aortic valve reduces turbulent kinetic energy levels and irreversible energy losses by over 75%, reaching values compatible with healthy subjects and conventional TAVIs. Our study substantiates that the 3D-printed heart valve displays a hemodynamic performance similar to established devices and underscores its potential for driving innovation towards patient specific valve prostheses.
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Affiliation(s)
- Till Zeugin
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, Swiss Federal Institute of Technology ETH Zürich, Zürich, Switzerland.
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland.
| | - Fergal B Coulter
- Complex Materials, Swiss Federal Institute of Technology ETH Zürich, Zürich, Switzerland
| | | | - André R Studart
- Complex Materials, Swiss Federal Institute of Technology ETH Zürich, Zürich, Switzerland
| | - Markus Holzner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Swiss Federal Institute for Water Science and Technology EAWAG, Dübendorf, Switzerland
- Institute of Hydraulic Engineering and River Research (IWA), University of Natural Resources and Life Sciences, Vienna, Austria
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Jahren SE, Demirel C, Bornemann KM, Corso P, Stortecky S, Obrist D. Altered blood flow due to larger aortic diameters in patients with transcatheter heart valve thrombosis. APL Bioeng 2023; 7:046120. [PMID: 38125699 PMCID: PMC10732696 DOI: 10.1063/5.0170583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023] Open
Abstract
The etiology of transcatheter heart valve thrombosis (THVT) and the relevance of the aortic root geometry on the occurrence of THVT are largely unknown. The first aim of this pilot study is to identify differences in aortic root geometry between THVT patients and patients without THVT after transcatheter aortic valve implantation (TAVI). Second, we aim to investigate how the observed difference in aortic diameters affects the aortic flow using idealized computational geometric models. Aortic dimension was assessed using pre-TAVI multi-detector computed tomography scans of eight patients with clinical apparent THVT and 16 unaffected patients (two for each THVT patient with same valve type and size) from the Bern-TAVI registry. Among patients with THVT the right coronary artery height was lower (-40%), and sinotubular junction (STJ) and ascending aorta (AAo) diameters tended to be larger (9% and 14%, respectively) compared to the unaffected patients. Fluid-structure interaction (FSI) in two idealized aortic models with the observed differences in STJ and AAo diameter showed higher backflow rate at the STJ (+16%), lower velocity magnitudes in the sinus (-5%), and higher systolic turbulent dissipation rate in the AAo (+8%) in the model with larger STJ and AAo diameters. This pilot study suggests a direct effect of the aortic dimensions on clinically apparent THVT. The FSI study indicates that larger STJ and AAo diameters potentially favor thrombus formation by increased backflow rate and reduced wash-out efficiency of the sinus. The reported observations require clinical validation but could potentially help identifying patients at risk for THVT.
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Affiliation(s)
- Silje Ekroll Jahren
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Caglayan Demirel
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | | | - Pascal Corso
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Stefan Stortecky
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Dominik Obrist
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
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Katz S, Caiazzo A, Moreau B, Wilbrandt U, Brüning J, Goubergrits L, John V. Impact of turbulence modeling on the simulation of blood flow in aortic coarctation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3695. [PMID: 36914373 DOI: 10.1002/cnm.3695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 02/10/2023] [Accepted: 02/20/2023] [Indexed: 05/13/2023]
Abstract
Numerical simulations of pulsatile blood flow in an aortic coarctation require the use of turbulence modeling. This paper considers three models from the class of large eddy simulation (LES) models (Smagorinsky, Vreman, σ -model) and one model from the class of variational multiscale models (residual-based) within a finite element framework. The influence of these models on the estimation of clinically relevant biomarkers used to assess the degree of severity of the pathological condition (pressure difference, secondary flow degree, normalized flow displacement, wall shear stress) is investigated in detail. The simulations show that most methods are consistent in terms of severity indicators such as pressure difference and stenotic velocity. Moreover, using second-order velocity finite elements, different turbulence models might lead to considerably different results concerning other clinically relevant quantities such as wall shear stresses. These differences may be attributed to differences in numerical dissipation introduced by the turbulence models.
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Affiliation(s)
- Sarah Katz
- Numerical Mathematics and Scientific Computing Research Group, Weierstrass Institute for Applied Analysis and Stochastics (WIAS), Berlin, Germany
| | - Alfonso Caiazzo
- Numerical Mathematics and Scientific Computing Research Group, Weierstrass Institute for Applied Analysis and Stochastics (WIAS), Berlin, Germany
| | - Baptiste Moreau
- Numerical Mathematics and Scientific Computing Research Group, Weierstrass Institute for Applied Analysis and Stochastics (WIAS), Berlin, Germany
| | - Ulrich Wilbrandt
- Numerical Mathematics and Scientific Computing Research Group, Weierstrass Institute for Applied Analysis and Stochastics (WIAS), Berlin, Germany
| | - Jan Brüning
- Deutsches Herzzentrum der Charité, Institute of Computer-assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Leonid Goubergrits
- Deutsches Herzzentrum der Charité, Institute of Computer-assisted Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
- Einstein Center Digital Future, Berlin, Germany
| | - Volker John
- Numerical Mathematics and Scientific Computing Research Group, Weierstrass Institute for Applied Analysis and Stochastics (WIAS), Berlin, Germany
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
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Polacin M, Geiger J, Burkhardt B, Callaghan FM, Valsangiacomo E, Kellenberger C. Quantitative evaluation of aortic valve regurgitation in 4D flow cardiac magnetic resonance: at which level should we measure? BMC Med Imaging 2022; 22:169. [PMID: 36167535 PMCID: PMC9513957 DOI: 10.1186/s12880-022-00895-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 09/08/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To find the best level to measure aortic flow for quantification of aortic regurgitation (AR) in 4D flow CMR. METHODS In 27 congenital heart disease patients with AR (67% male, 31 ± 16 years) two blinded observers measured antegrade, retrograde, net aortic flow volumes and regurgitant fractions at 6 levels in 4D flow: (1) below the aortic valve (AV), (2) at the AV, (3) at the aortic sinus, (4) at the sinotubular junction, (5) at the level of the pulmonary arteries (PA) and (6) below the brachiocephalic trunk. 2D phase contrast (2DPC) sequences were acquired at the level of PA. All patients received prior transthoracic echocardiography (TTE) with AR severity grading according to a recommended multiparametric approach. RESULTS After assigning 2DPC measurements into AR grading, agreement between TTE AR grading and 2DPC was good (κ = 0.88). In 4D flow, antegrade flow was similar between the six levels (p = 0.87). Net flow was higher at level 1-2 than at levels 3-6 (p < 0.05). Retrograde flow and regurgitant fraction at level 1-2 were lower compared to levels 3-6 (p < 0.05). Reproducibility (inter-reader agreement: ICC 0.993, 95% CI 0.986-0.99; intra-reader agreement: ICC 0.982, 95%CI 0.943-0.994) as well as measurement agreement between 4D flow and 2DPC (ICC 0.994; 95%CI 0.989 - 0.998) was best at the level of PA. CONCLUSION For estimating severity of AR in 4D flow, best reproducibility along with best agreement with 2DPC measurements can be expected at the level of PA. Measurements at AV or below AV might underestimate AR.
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Affiliation(s)
- Malgorzata Polacin
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. .,Department of Diagnostic Imaging, University Children`s Hospital, University of Zurich, Zurich, Switzerland.
| | - Julia Geiger
- Department of Diagnostic Imaging, University Children`s Hospital, University of Zurich, Zurich, Switzerland
| | - Barbara Burkhardt
- Division of Pediatric Cardiology, Pediatric Heart Center, University Children`s Hospital, University of Zurich, Zurich, Switzerland
| | - Fraser M Callaghan
- Center for MR Research, University Children's Hospital, University of Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital, University of Zurich, Zurich, Switzerland
| | - Emanuela Valsangiacomo
- Division of Pediatric Cardiology, Pediatric Heart Center, University Children`s Hospital, University of Zurich, Zurich, Switzerland
| | - Christian Kellenberger
- Department of Diagnostic Imaging, University Children`s Hospital, University of Zurich, Zurich, Switzerland
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Mid-term outcomes of patients with Lotus and Evolut transcatheter valves. ADVANCES IN INTERVENTIONAL CARDIOLOGY 2022; 18:146-153. [PMID: 36051828 PMCID: PMC9421513 DOI: 10.5114/aic.2022.118531] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/06/2022] [Indexed: 11/18/2022] Open
Abstract
Introduction Long-term data on the Lotus® (Boston Scientific, USA) valve are lacking. Aim To evaluate mid-term outcomes of aortic stenosis patients treated with either Lotus or Evolut R® valves (Medtronic, USA). Material and methods Our study sample comprised 190 patients (71 Lotus and 119 Evolut valves). The mean clinical follow-up was 2.0 ±0.9 years. Information on mortality was obtained from the National Institutes of Health Information and Statistics. Results No significant differences existed in baseline characteristics between the groups. The rate of procedural complications was low and without significant differences between groups. The log rank test showed higher mortality in the Lotus group for cardiovascular mortality (p = 0.02; RR = 2.4, 95% CI: 1.123–5.075). Multivariable analysis revealed that the Lotus valve was independently associated with cardiovascular mortality (p = 0.03). At the end of echocardiography follow-up (4.1 ±0.9 years), we found a significantly higher mean aortic valve gradient (AVGm) in the Lotus group than in the Evolut group (17.9 ±9.5 vs. 10.2 ±3.5 mm Hg; p = 0.0006), and 3 (10%) patients from the Lotus group suffered from symptomatic re-stenosis requiering re-intervention. Conclusions The results of our study suggest that higher cardiovascular mortality rates during mid-term follow-up were associated with Lotus compared with Evolut valves. Higher AVGm in the Lotus valves suggests the possibility of accelerated prosthesis degeneration.
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