ABSTRACT
Objective: The use of the transcatheter aortic valve in low-risk patients might lead to a second intervention due to the deterioration of the first 1. Understanding the implantation height is key to an effective redo transcatheter aortic valve replacement treatment. Methods: The effects of implantation height on the performance of a balloon-expandable valve within a self-expandable valve were assessed using hemodynamic testing and particle image velocimetry. The hemodynamic performances, leaflet kinematics, and turbulent shear stresses were measured and compared. Results: When a second balloon-expandable valve was positioned at varying heights relative to the first self-expandable valve, the leaflet motion of the first valve transitioned from free opening and closing to overhanging, and eventually to being entirely pinned to the stent, forming a neo-skirt. When the leaflets of the self-expandable valve could move freely, a decrease in regurgitation fraction was observed, but with an increased pressure gradient across the valve. Flow visualization indicated that the overhanging leaflets disrupted the flow, generating a higher level of turbulence. Conclusions: This study suggests that the overhanging leaflets should be avoided, whereas the other 2 scenarios should be carefully evaluated based on an individual patient's anatomy and the cause of failure of the first valve.
ABSTRACT
Objective@#Conebeam CT (CBCT) was used to measure the palatine between the maxillary first and second molars. The proximal and distal palatal widths of the maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nail were implanted at different angles provided a reference for the clinical selection of microscrew implant placement.@* Methods@#The image data of 90 adult patients were selected as the research object, and the jaw bone was reconstructed by scanning. In maxillary palatine, selection of distances at 12 mm, 14 mm, 16 mm, and 18 mm from the palatal apex of maxillary first molar between the maxillary first and second molar were used as measurement, measured the proximal and distal palatal widths of maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nails were implanted at 30 °, 45 °, 60 °, and 90 °. SPSS 26.0 software was used for one-way ANOVA and LSD pair comparison. @*Results@#The larger the angle of the microscrew implant anchorage nail was, the smaller the proximal and distal medial widths between the maxillary first and second molar, and the difference was statistically significant (P < 0.05). Compared with the 90° direction, the proximal and distal medial widths of the microscrew implant anchorage nail were larger in the 60° direction. The greater the angle of implantation, the smaller the mucosal thickness and the greater the bone tissue thickness, and the results showed a significant difference (P < 0.001). Compared with the direction of 30° and 45°, the mucosal thickness at the direction of 60° was smaller, and the bone tissue thickness was larger. The higher the position of the microscrew implant anchorage nail, the greater the width of the proximal and distal medial, and the difference was statistically significant (P < 0.05). Compared with the positions 12 and 14 mm from the palatal tip, the proximal and distal medial widths of the microscrew implant anchorage nail were larger. The higher the implant position was, the greater the mucosal thickness and the smaller the bone tissue thickness. The results showed a significant difference (P < 0.001). Compared with the position of 18 mm from the palatal tip of the maxillary first molar, the mucosal thickness was smaller and the bone tissue thickness was larger.@*Conclusion@#It is most appropriate to implant microscrew implant anchorage nail at least 10 mm in length in the direction of 60° at the palatal apex 16 mm from the maxillary first molar in palatine between the first and second molar.
ABSTRACT
TAVR in bicuspid aortic valve (BAV) represents a challenging scenario. Valve sizing and positioning are the most important determinants of procedural success. In BAV the maximal prosthesis-anatomy interference occurs at the supra-annular level. Supra-annular prosthesis implantation may improve valve sealing and hemodynamic result. In this case series, we propose a new site for prosthesis implantation, guided CT scan supra-annular sizing for BAV undergoing TAVR.
