To plan valve implantation in bicuspid aortas (BAV) through transcatheter aortic valve replacement (TAVR), a series of well-defined procedural steps must be followed. Here is a summary of the main steps from the document:Transcatheter Aortic Valve Replacement for Bicuspid Aortic Valve Stenosis: A Practical Operative Overview

 

Characterization of BAV Morphology:

• Use cardiac-synchronized multislice computed tomography (CT) to accurately evaluate the bicuspid aortic valve and identify the type of BAV, as classified by Sievers and Schmidtke (type 0, 1, and 2) or the TAVR-specific classification by Jilaihawi et al.
• Determine the presence of raphe and the number of commissures, as these elements influence the interaction with transcatheter heart valves (THVs)

Assessment of the Virtual Basal Ring (VBR):

• In the case of BAV without raphe, the virtual basal ring must be defined manually, as it has only two anatomical hinge points.
• For BAV with bi-commissural or tri-commissural raphe, the definition of the VBR is more accurate, with area and perimeter measurements to determine the prosthetic size and height of the implant.

Assessment of the Virtual Raphe Ring (VRR):

• In some cases, it may be necessary to consider a supra-annular plane, the VRR, for the sizing of the prosthesis, especially if the basal ring is not the narrowest part of the aortic root.
• Measure the supra-annular perimeter, intercommissural distance, and raphe specifications (length, degree, and distribution of calcification).

Graft Size Selection:

• Compare the basal ring (BRR) and raphe ring (VRR) sizes to determine the dominant pattern (codominant, VBR-dominant, or VRR-dominant).
• Apply an annular-based or supra-annular-based sizing strategy depending on the dominant pattern and anatomical characteristics.

Graft Type Selection:

• Consider balloon-expandable or self-expandable grafts based on anatomical characteristics and available evidence.
• Graft selection should be individualized based on patient characteristics and anticipated interaction with surrounding anatomy.

Procedural Considerations:

• Use balloon valvuloplasty to facilitate graft passage and expansion, as well as test raphe resistance and define device size.
• The graft implantation technique should be tailored based on aortic root configuration (codominant, BRR-dominant, VRR-dominant).

Post-Implantation Dilation:

• Limit post-dilation to cases with significant paravalvular leaks or residual transvalvular gradients to reduce complications.
• Assess potential complications such as coronary obstruction and stent-graft distortion.

Brain Protection and Coronary Access:

• Consider the use of embolic brain protection devices during TAVR in BAV, given the association with increased risk of stroke.
• Pay particular attention to post-TAVR coronary access, especially in the presence of anatomical features that could increase the risk of coronary obstruction.

Future Considerations and Limitations:

• The need for randomized, controlled trials to compare TAVR with AVR surgery in patients with BAV and to determine the efficacy of different transcatheter stent-grafts in BAV.
• Appropriately plan future valve-in-valve procedures to reduce the risk of coronary obstruction and compromise coronary access.

 

Here are the main steps to follow with the software to measure the virtual raphe ring (VRR or VBR) in the case of a bicuspid aortic valve:

Computerized Tomography (CT) Preparation: Acquire multislice cardiac synchronized CT images of the entire heart during the entire cardiac cycle for an accurate assessment of the bicuspid aortic valve.

Identification of the Measurement Planes: Determine the appropriate plane where we find the narrowest dimensions. This plane can vary depending on the type of bicuspid: codominant, VBR-dominant, or VRR-dominant.

Tracing of the Projected Neo Annulus: Trace the internal margins of the cusps with the valve open in systole to define the projected neo annulus (VRR or VBR). It is important to avoid bulky surrounding structures such as calcifications (Sinus Sequestration). 

Calculating the Supra Annular Perimeter: Calculate the perimeter of the neoannulus rather than the area due to the irregular shape of the supra annular structure. The perimeter allows us to derive the diameter needed for sizing the prosthesis.

Misurazioni Specifiche del Raphe: Calculating the Supra Annular Perimeter:.

Intercommissural Distance Measurement: Measure the intercommissural distance corresponding to the largest supra annular diameter. This measurement is crucial to assess the eccentricity and general anatomical characteristics of the aortic root.

Ante-Raphe Space Determination: Measure the ante-raphe space, which corresponds to the smallest supra annular diameter. This value is used to further assess the configuration and suitability of the VRR plan.

Confirmation and Review of Measurements: Review all measurements and confirm that the VRR plan accurately represents the patient’s anatomical structure. Make any necessary adjustments based on the specific characteristics of the bicuspid valve.

 

Take notes on the journey…