Bipolar Off-Wall Electrode for Renal Nerve Ablation
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Solution Overview
Problem
Conventional methods for ablating perivascular renal nerves to treat hypertension often result in renal artery injury due to high current density and limited accessibility, especially in patients with short or multiple renal arteries, and require larger electrodes to reduce heating, which complicates the procedure and extends treatment time.
Innovation Solution
A bipolar off-wall RF electrode configuration is used, where electrodes are positioned a short distance away from the renal artery wall, reducing current density and minimizing thermal injury to the artery while effectively ablating perivascular nerves and ganglia, employing a spacing structure to maintain electrodes at a predefined distance from the tissue during ablation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ablation methods are used with electrodes in direct contact with the renal artery wall, then effective ablation of perivascular nerves is achieved, but renal artery injury occurs due to high current density and thermal damage
Solution Approach 1:
The patent introduces an electrical insulator as an intermediary between the electrode and the renal artery wall. This insulator allows the electrode to be positioned in direct contact with the artery wall for effective ablation while preventing harmful thermal injury to the artery wall. The insulator acts as a mediator that enables the ablation function while blocking the harmful thermal effects.
2Object-affected harmful factors
If larger electrodes are used to reduce current density and minimize thermal injury, then renal artery injury is reduced, but device complexity and procedure time increase
Solution Approach 1:
The patent changes the electrical properties of the insulator material to optimize current density distribution. By carefully selecting the electrical resistance and other parameters of the insulator, the system achieves effective ablation with controlled current density without requiring larger electrodes, thus avoiding increased device complexity.
3Object-affected harmful factors
If electrodes are positioned away from the artery wall to reduce current density, then thermal injury is minimized, but heat transfer to target tissues becomes insufficient for effective ablation
Solution Approach 1:
The electrical insulator serves as a thermal mediator that facilitates heat transfer from the electrode to the target perivascular nerves while preventing excessive thermal injury to the renal artery wall. The insulator's thermal properties are optimized to allow sufficient heat conduction for effective ablation while limiting peak temperatures at the artery wall interface.
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 approach effectively ablates renal sympathetic nerves and ganglia with reduced renal artery injury, allowing for more efficient treatment of hypertension by maintaining effective heat transfer to target tissues while minimizing damage to the artery walls, and can be adapted for various renal anatomies.
Implementation Method 1
high frequency alternating current delivered to bipolar electrodes positioned a distance away from the inner wall of a renal artery during ablation
Implementation Method 2
positioning apparatus to maintain a gap between electrodes of a bipolar electrode arrangement and tissue of the body
Data Source
AI summary
A first spacing structure is provided at a distal end of a first catheter. The first spacing structure is configured to position at least one arterial electrode at a predefined distance away from a wall of the renal artery. A second spacing structure is provided at the distal end of the first catheter or at a distal end of a second catheter. The second spacing structure is configured to position at least one aortal electrode at a predefined distance away from a wall of the aorta. The arterial and aortal electrodes are operable as a bipolar electrode arrangement. The first and second spacing structures respectively maintain the arterial and aortal electrodes at a predefined distance away from the renal artery and aortal walls while electrical energy sufficient to ablate perivascular nerve tissue adjacent the renal artery and aortal walls is delivered by the bipolar electrode arrangement.