title: Impact of different aortic valve calcification patterns on the outcome of transcatheter aortic valve implantation: A finite element study.
abstract: Transcatheter aortic valve implantation (TAVI) can treat symptomatic patients with calcific aortic stenosis. However, the severity and distribution of the calcification of valve leaflets can impair the TAVI efficacy. Here we tackle this issue from a biomechanical standpoint, by finite element simulation of a widely adopted balloon-expandable TAVI in three models representing the aortic root with different scenarios of calcific aortic stenosis. We developed a modeling approach realistically accounting for aortic root pressurization and complex anatomy, detailed calcification patterns, and for the actual stent deployment through balloon-expansion. Numerical results highlighted the dependency on the specific calcification pattern of the "dog-boning" of the stent. Also, local stent distortions were associated with leaflet calcifications, and led to localized gaps between the TAVI stent and the aortic tissues, with potential implications in terms of paravalvular leakage. High stresses were found on calcium deposits, which may be a risk factor for stroke; their magnitude and the extent of the affected regions substantially increased for the case of an "arc-shaped" calcification, running from commissure to commissure. Moreover, high stresses due to the interaction between the aortic wall and the leaflet calcifications were computed in the annular region, suggesting an increased risk for annular damage. Our analyses suggest a relation between the alteration of the stresses in the native anatomical components and prosthetic implant with the presence and distribution of relevant calcifications. This alteration is dependent on the patient-specific features of the calcific aortic stenosis and may be a relevant indicator of suboptimal TAVI results.
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy. Electronic address: francesco.sturla@polimi.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sturla
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Ronzoni
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Vitali
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Dimasi
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vismara
authors.affiliation: UCL Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, University College London, London, UK.
authors.forename: Georgia
authors.initials: G
authors.lastname: Preston-Maher
authors.affiliation: UCL Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, University College London, London, UK.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Burriesci
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Votta
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Redaelli
mesh_terms: D001021:Aortic Valve / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D001696:Biomechanical Phenomena; D002114:Calcinosis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D020342:Finite Element Analysis; D006801:Humans; D055595:Mechanical Phenomena; D012307:Risk Factors; D015607:Stents; D065467:Transcatheter Aortic Valve Replacement; D016896:Treatment Outcome
keywords: Aortic stenosis; Biomechanics; Calcifications; Finite element models; TAVI