Sensing Catheter Sizing Valve Annulus Geometry
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Solution Overview
Problem
Current methods for sizing the native valve annulus during trans-catheter aortic valve replacement (TAVR) procedures are inaccurate and costly, often resulting in paravalvular aortic regurgitation due to the elliptical shape and calcification of the valve annulus, which complicates the deployment and anchoring of prosthetic valves.
Innovation Solution
A sensing catheter system with radially expandable splines and sensing coils is used to determine the dimensions and compliance of the native valve annulus by generating a magnetic field and measuring induced potentials, allowing for precise geometry and compliance assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional imaging techniques (TTE, TEE, angiography) are used for valve annulus sizing, then the procedure is cost-effective and safe, but the measurement precision is insufficient due to the elliptical shape and calcification of the valve annulus
Solution Approach 1:
The sizing catheter is divided into multiple splines (typically 3-6) that can be independently deployed and positioned around the valve annulus. Each spline contains sensing coils that independently measure local dimensions, allowing the system to map the elliptical geometry and calcification patterns of the annulus by combining data from multiple segmented measurement points rather than relying on a single imaging view
Solution Approach 2:
The patent replaces traditional mechanical/imaging-based sizing methods (echocardiography, angiography, CT) with an electromagnetic sensing system. Magnetic fields are generated by drive coils and sensed by sensing coils on the splines to determine the positions and dimensions of the valve annulus, eliminating the need for complex imaging equipment and reducing radiation exposure while improving measurement accuracy
2Measurement precision
If 3D CT imaging is used for valve annulus sizing, then the measurement precision is improved with less PV AR, but the cost increases and the patient is exposed to harmful radiation
Solution Approach 1:
The patent replaces ionizing radiation-based CT imaging with a non-ionizing electromagnetic sensing system using magnetic fields. The sensing coils detect magnetic field changes to determine annulus dimensions without exposing the patient to harmful radiation, while maintaining measurement precision through direct contact measurement with the valve annulus using the spline-based catheter system
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the sizing catheter and the valve annulus. Instead of using penetrating radiation (X-rays), the system uses magnetic fields that can be generated and detected by coils, providing a safe intermediary mechanism for measuring annulus geometry without direct radiation exposure to the patient
3Ease of operation
If balloon valvuloplasty is performed before valve implantation, then the valve annulus is dilated to improve valve deployment, but the geometry changes make accurate sizing difficult
Solution Approach 1:
The patent performs valve annulus sizing using the spline-based catheter before balloon valvuloplasty to establish baseline dimensions and identify calcification patterns. This preliminary measurement allows the surgical team to plan the appropriate valve size and deployment strategy before the annulus geometry is altered by balloon dilation, ensuring accurate sizing is captured before the structural changes occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides accurate and cost-effective sizing of the native valve annulus, reducing the risk of paravalvular regurgitation and improving the long-term success of TAVR procedures by ensuring proper valve deployment and anchoring.
Implementation Method 1
a transmitter to generate a magnetic field to induce a potential in each of the sensing coils
Data Source
AI summary
A system for determining the dimensions of a native valve annulus may include a sensing catheter, a transmitter, and a computing device. The sensing catheter may include a shaft extending in a longitudinal direction; a plurality of splines attached to the shaft, the splines having an expanded condition spaced radially outward from the shaft; and at least one sensing coil located on each of the splines. The transmitter may generate a magnetic field to induce a potential in each of the sensing coils, and the computing device may identify the positions of the sensing coils based on the induced potentials.