Patient-specific simulations of transcatheter aortic valve stent implantation

Abstract

Transcatheter aortic valve implantation (TAVI) enables treatment of aortic stenosis with no need for open heart surgery. According to current guidelines, only patients considered at high surgical risk can be treated with TAVI. In this study, patient-specific analyses were performed to explore the feasibility of TAVI in morphologies, which are currently borderline cases for a percutaneous approach. Five patients were recruited: four patients with failed bioprosthetic aortic valves (stenosis) and one patient with an incompetent, native aortic valve. Three-dimensional models of the implantation sites were reconstructed from computed tomography images. Within these realistic geometries, TAVI with an Edwards Sapien stent was simulated using finite element (FE) modelling. Engineering and clinical outcomes were assessed. In all patients, FE analysis proved that TAVI was morphologically feasible. After the implantation, stress distribution showed no risks of immediate device failure and geometric orifice areas increased with low risk of obstruction of the coronary arteries. Maximum principal stresses in the arterial walls were higher in the model with native outflow tract. FE analyses can both refine patient selection and characterise device mechanical performance in TAVI, overall impacting on procedural safety in the early introduction of percutaneous heart valve devices in new patient populations.

Fluid–Structure Interaction Model of a Percutaneous Aortic Valve: Comparison with an In Vitro Test and Feasibility Study in a Patient-Specific Case

“…Although in recent years numerical studies in this field have emerged, as far as the authors are aware, fluid-structure simulations of percutaneous valves are absent. Only structural 3,6,14,17,23,32,39 or fluid dynamics 3,13,31,37 studies have been carried out. This study used FSI simulations both in the in vitro durability testing and in the patient-specific set-up.…”

“…In the literature, mathematical models related to TAVR are increasing. They can be related to the understanding of the mechanical behavior of the stented valve, the aortic root and the leaflet dynamics from a structural point of view 3,6,14,17,23,32,39 or to the hemodynamics inside the treated aortic root. 3,13,31,37 To the best of our knowledge, scientific publications which take into account both the mechanical and the fluid aspects in a coupled manner are absent.…”

Patient-specific image-based computer simulation for theprediction of valve morphology and calcium displacement after TAVI with the Medtronic CoreValve and the Edwards SAPIEN valve

“…As mentioned above, There is growing interest in the development of software which is able to construct detailed geometric anatomic models from patient-specific diagnostic images and software that allows computer simulation of TAVI in order to predict valve configuration in the patient-specific anatomy, thereby helping the physician to select the valve (type and size) that best fits the individual patient [14][15][16][17][18][19][20][21][22] . A number of studies have employed finite element computer modelling to deploy a transcatheter aortic valve virtually into a patient-specific aortic root model [14][15][16]19,21,22 . While all of these studies have definitely contributed to proving the feasibility of patient-specific TAVI simulations, the validation of the modelling results has been limited so far.…”

“…The increasing number and spectrum of patients referred for TAVI as well as the increasing valve types available necessitate patient-specific tools predicting device-host interaction for both patient selection and procedure planning (i.e., selection of the valve that best fits the individual patient). Finite element computer simulation of a TAVI procedure based upon the integration of the patient-specific anatomy, the physical and mechanical properties of the valve and the biomechanical properties of the aortic root, may help to define in vivo device-host interactions, thereby enhancing the safety of TAVI [14][15][16][17][18][19][20][21][22] .…”

Transcatheter aortic valve replacement in patients with high aortic anguation

“…Finite-element models analyses can both refine patient selection and characterize device mechanical performance in TAVR, thus enhancing the safety and efficacy in high-risk patients (18). In the setting of high AA, this simulation model could provide operator with potential implications before TAVR procedure.…”