Simulation of transcatheter aortic valve implantation under consideration of leaflet calcification

Abstract

Transcatheter aortic valve implantation (TAVI) is a minimally invasive off-pump procedure to replace diseased aortic heart valves. Known complications include paravalvular leaks, atrioventricular blocks, coronary obstruction and annular rupture. Careful procedure planning including appropriate stent selection and sizing are crucial. Few patient-specific geometric parameters, like annular diameters, annular perimeter and measurement of the distance to the coronary ostia, are currently used within this process. Biomechanical simulation allows the consideration of extracted anatomy and material parameters for the intervention, which may improve planning and execution phases. We present a simulation workflow using a fully segmented aortic root anatomy, which was extracted from pre-operative CT-scan data and apply individual material models and parameters to predict the procedure outcome. Our results indicate the high relevance of calcification location and size for intervention planning, which are not sufficiently considered at this time. Our analysis can further provide guidance for accurate, patient-specific device positioning and future adaptations to stent design.

Assessing the impact of including leaflets in the simulation of TAVI deployment into a patient-specific aortic root

“…Such verification extends to the value of including the prosthetic leaflets when deploying a device into a patient specific aortic root. Other recent attempts at modelling TAVI device deployment have neglected the leaflets or employed approximate models for them (Auricchio et al 2014;Capelli et al 2012;Russ et al 2013;Tzamtzis et al 2013;Wang et al 2012;Wang et al 2014). Most notably, Auricchio et al (2014), successfully simulated a TAVI frame deployment into an aortic root and then developed a leaflet model within the frame in its post-procedural position.…”

“…To date there have been relatively few papers published that describe computational methods for simulating TAVI deployment. Most of the papers neglected to include either the leaflets or the cuff (Capelli et al 2012;Russ et al 2013;Tzamtzis et al 2013;Wang et al 2012;Wang et al 2014). Only a single paper included prosthetic leaflets but modelled them using a post deployment mapping technique to align the leaflets with the frame (Auricchio et al 2014)).…”

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

“…Sixty percent of the cases with coronary obstruction reviewed by Ribeiro et al had a coronary ostium height >10 mm, suggesting that other factors might be involved, such as the size and location of calcium nodules on the leaflets and the size of the sinuses of Valsalva. With respect to MSCT-based planning, computer simulation incorporating the calcium load of the base of the aortic root including leaflets such as reported in the current study and by Russ et al may help to predict coronary obstruction more precisely 16 . Similarly, preoperative assessment of the risk of paravalvular aortic regurgitation may be improved by the proposed computer model.…”

“…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] .…”