Transcatheter procedures are transforming the treatment of heart valve conditions, particularly with regards to aortic valve stenosis. As TAVR is still a fairly new technology, challenges remain where precise pre-operative planning can play a crucial role. FEops is a company that focuses on the role simulations can play in optimizing transcatheter cardiovascular devices and patient-tailored interventions. They rely on the Mimics Innovation Suite to prepare the models which are used in these simulations.

FEops: Better Healthcare Through Simulations

Aortic valve annulus measurements performed on the re-sampled images
FEops strives to develop novel realistic simulation technologies for transcatheter cardiovascular devices. FEops continuously improves its in-house developed simulation tools to help medical device companies and doctors advance novel transcatheter cardiovascular devices, delivery systems and procedures. In addition, FEops uses its simulation expertise to perform and support basic research in the field of minimally invasive surgery with the final aim of improving patient treatment.

Computer Simulations to Predict Valvular Regurgitation

Device selection for TAVR is primarily based on aortic annulus measurements, often from pre-operative MSCT data. However, optimal size selection based on these measurements is challenging due to the fact that the aortic annulus is not circular and may deform with the deployment of a TAVR device. Moreover, calcifications may deform the valve frame, leading to a sub-optimal apposition and potentially to valvular regurgitation.

The FEops team applied their patient-specific computer simulation expertise to the development of the TAVIguideTM technology. It is a web-based, pre-operative planning service for TAVR cases. Starting from pre-operative MSCT images and using the Mimics Innovation Suite, FEops performs multiple measurements on the re-sampled images, including aortic annulus diameters, ellipticity, perimeter and area. The aortic root, including the calcifications, is then segmented and reconstructed in 3D. The 3D model is finally converted to a finite element mesh and combined with a transcatheter aortic valve model. Several predictions can be made by using advanced, non-linear finite element simulations: stent frame deformation, incomplete frame apposition, calcium movement and more. This allows the team to assess the risk of complications, such as regurgitation, prior to the intervention.

 3D representation of the pre-operative aortic root, including valve leaflets and calcifications

Visualization of deployed CoreValve in patient-specific aortic root model

Validation Study

3D visualization of frame and skirt apposition (red = malapposed)

In order to validate the results obtained through computer simulations, the engineers at FEops established a collaborative study with the Erasmus MC, in Rotterdam (Netherlands). In a first retrospective pilot study, 18 patients who received a 26 and 29mm Medtronic Corevalve® were included. MSCT data was obtained for each patient shortly after the intervention. The stent frame was segmented using the Mimics Innovation Suite. The 3D reconstruction of the post-operative valve was then overlaid and compared with the prediction of the computer simulation.

Comparison of predicted (left) and observed (CT, right) calcium movement

A quantitative analysis of the frame deformation was performed by measuring minimal and maximal diameter, cross-sectional area and perimeter on cross-sections at multiple levels of the CoreValve®. Overall, there is a strong and significant correlation between the observed and predicted measurements for all dimensions (r > 0.80, p < 0.001). The accuracy of the predicted frame deformation was confirmed by a Blant-Altman analysis, but further validation from a larger patient group is required and ongoing. If the current results are confirmed, this process could become the industry standard for device selection.

Why choose Mimics® Innovation Suite?

  • It's the industry standard for accurate segmentation
  • Importing a wide variety of medical imaging formats is simple
  • It's easy to use and helps to reduce training time
  • Mimics® has the regulatory clearance to be considered a medical device

 

How can computational modelling and simulation give medical device companies the opportunity to integrate valve design with patient-specific testing ? Check our webinar with Prof. Dr. Ir. Matthieu De Beule, CEO and founder of FEops

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