title: Biomechanical properties of the Marfan's aortic root and ascending aorta before and after personalised external aortic root support surgery.
abstract: Marfan syndrome is an inherited systemic connective tissue disease which may lead to aortic root disease causing dilatation, dissection and rupture of the aorta. The standard treatment is a major operation involving either an artificial valve and aorta or a complex valve repair. More recently, a personalised external aortic root support (PEARS) has been used to strengthen the aorta at an earlier stage of the disease avoiding risk of both rupture and major surgery. The aim of this study was to compare the stress and strain fields of the Marfan aortic root and ascending aorta before and after insertion of PEARS in order to understand its biomechanical implications. Finite element (FE) models were developed using patient-specific aortic geometries reconstructed from pre and post-PEARS magnetic resonance images in three Marfan patients. For the post-PEARS model, two scenarios were investigated-a bilayer model where PEARS and the aortic wall were treated as separate layers, and a single-layer model where PEARS was incorporated into the aortic wall. The wall and PEARS materials were assumed to be isotropic, incompressible and linearly elastic. A static load on the inner wall corresponding to the patients' pulse pressure was applied. Results from our FE models with patient-specific geometries show that peak aortic stresses and displacements before PEARS were located at the sinuses of Valsalva but following PEARS surgery, these peak values were shifted to the aortic arch, particularly at the interface between the supported and unsupported aorta. Further studies are required to assess the statistical significance of these findings and how PEARS compares with the standard treatment.
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: S D
authors.initials: SD
authors.lastname: Singh
authors.affiliation: Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. Electronic address: yun.xu@imperial.ac.uk.
authors.forename: X Y
authors.initials: XY
authors.lastname: Xu
authors.affiliation: Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, UK; National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Pepper
authors.affiliation: Clinical Operational Research, Department of Mathematics, University College London, 4 Taviton Street, London WC1H 0BT, UK.
authors.forename: T
authors.initials: T
authors.lastname: Treasure
authors.affiliation: Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, UK; National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK.
authors.forename: R H
authors.initials: RH
authors.lastname: Mohiaddin
mesh_terms: D001011:Aorta / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D001018:Aortic Diseases / Q000209:etiology / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D001794:Blood Pressure; D001807:Blood Vessel Prosthesis; D055424:Cardiac-Gated Imaging Techniques; D003198:Computer Simulation; D055119:Elastic Modulus; D004562:Electrocardiography; D020342:Finite Element Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008382:Marfan Syndrome / Q000150:complications / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D008955:Models, Cardiovascular; D013312:Stress, Physiological; D016896:Treatment Outcome
keywords: Aortic root dilatation; Finite element modelling; Marfan syndrome; Vascular prosthetics