Computer Assisted Transcatheter Heart Valve Implantation In Valve-in-valve Procedures
Vito Giovanni Ruggieri, Reda Belhaj Soulami, Hung Nguyen-Duc, Miguel Castro, Vincent Auffret, Pascal Haigron, Jean Philippe Verhoye.
Pontchaillou University Hospital, Rennes, France.
OBJECTIVE: Valve-in-Valve (VIV) procedures are increasingly being considered as an alternative to redo surgery in the treatment of degenerated bioprosthetic heart valves in selected high-risk patients. These procedures remain however technically demanding, particularly regarding transcatheter heart valve (THV) positioning and implantation inside the degenerated tissue valve. The objective of our study was to evaluate the feasibility and assess the benefits of computer guidance in THV implantation during VIV procedures.
METHODS: ECG gated CT-scan images were segmented to extract the degenerated bioprosthesis stent and the ascending aorta, creating virtual 3D reconstructions. A virtual plane was subsequently added to the 3D reconstruction of the tissue valve’s stent, indicating the optimal implantation area (OIA) of the THV inside the tissue valve. The OIA was defined based on the degenerated bioprosthesis design and the planned THV for the procedure.
A 3D/2D feature-based registration was used to superimpose the 3D reconstructions, while dynamic tracking and image fusion allowed maintaining the projection onto fluoroscopic sequences. The THV was afterwards aligned with the indicated AOI, and implanted inside the tissue valve.
Before and after THV implantation, the projection of the ascending aorta and the coronary arteries assessed the risk of coronary ostia obstruction.
RESULTS: Five procedures were retrospectively evaluated using our approach to validate our model. The mean superimposition error was 1,1 mm (0,4 - 2,2mm). In all procedures, the necessary time to perform the superimposition was under fifteen seconds.
We then carried out two live cases using our approach, successfully implanting the THV inside the degenerated tissue valve, with no residual intervalvular regurgitation and satisfactory transvalvular gradients, while reducing the need for contrast injection.
CONCLUSIONS: Our study demonstrates the feasibility of a computer-guided implantation of THV in VIV procedures, using 3D reconstructions based on the preoperative CT-scan data. Moreover, it underlines the benefits of augmented reality in such procedures: securing the THV implantation, increasing the reproducibility and enhancing the outcomes. The results of this feasibility study are currently being evaluated on more cases, before being extended to more challenging stented tissue valves and evaluation on stentless valves.
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