title: In vitro and in silico approaches to quantify the effects of the Mitraclip®system on mitral valve function.
abstract: Mitraclip®implantation is widely used as a valid alternative to conventional open-chest surgery in high-risk patients with severe mitral valve (MV) regurgitation. Although effective in reducing mitral regurgitation (MR) in the majority of cases, the clip implantation produces a double-orifice area that can result in altered MV biomechanics, particularly in term of hemodynamics and mechanical stress distribution on the leaflets. In this scenario, we combined the consistency of in vitro experimental platforms with the versatility of numerical simulations to investigate clip impact on MV functioning. The fluid dynamic determinants of the procedure were experimentally investigated under different working conditions (from 40bpm to 100bpm of simulated heart rate) on six swine hearts; subsequently, fluid dynamic data served as realistic boundary conditions in a computational framework able to quantitatively assess the post-procedural MV biomechanics. The finite element model of a human mitral valve featuring an isolated posterior leaflet prolapse was reconstructed from cardiac magnetic resonance. A complete as well as a marginal, sub-optimal grasping of the leaflets were finally simulated. The clipping procedure resulted in a properly coapting valve from the geometrical perspective in all the simulated configurations. Symmetrical complete grasping resulted in symmetrical distribution of the mechanical stress, while uncomplete asymmetrical grasping resulted in higher stress distribution, particularly on the prolapsing leaflet. This work pinpointed that the mechanical stress distribution following the clipping procedure is dependent on the cardiac hemodynamics and has a correlation with the proper execution of the grasping procedure, requiring accurate evaluation prior to clip delivery.
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, 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, Milano, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vismara
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Michal
authors.initials: M
authors.lastname: Jaworek
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Votta
authors.affiliation: Abbott Vascular International, Bruxelles, Belgium.
authors.forename: Paolo
authors.initials: P
authors.lastname: Romitelli
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy; Division of cardiovascular Surgery, Università degli Studi di Verona, Verona, Italy.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Pappalardo
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Lucherini
authors.affiliation: Forcardiolab, Fondazione per la ricerca in Cardiochirurgia ONLUS, Milan, Italy; Cardiovascular Surgery Department, "Luigi Sacco" University general Hospital, Milan, Italy; Università degli Studi di Milano, Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Antona
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Gianfranco B
authors.initials: GB
authors.lastname: Fiore
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Redaelli
mesh_terms: D000818:Animals; D002302:Cardiac Output; D003198:Computer Simulation; D020342:Finite Element Analysis; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000503:physiopathology* / Q000601:surgery; D008944:Mitral Valve Insufficiency / Q000503:physiopathology; D008945:Mitral Valve Prolapse / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D008955:Models, Cardiovascular; D034421:Sus scrofa
keywords: Experimental platforms; Finite element models; Mitraclip(®); Mitral valve; Percutaneous procedure