Expandable Catheter for Circumferential Ablation
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Solution Overview
Problem
Current technologies for treating cardiac arrhythmias and hypertension using radiofrequency catheter systems are inefficient, time-consuming, and pose safety risks due to challenges in reproducible circumferential ablation of tissue around blood vessel ostia, leading to potential complications such as thermal injury, radiation exposure, and incomplete nerve ablation.
Innovation Solution
A disposable catheter system with multiple expandable injector tubes and a centering mechanism that allows for precise and controlled injection of ablative fluid around the ostium of blood vessels, reducing the risk of perforation and ensuring complete tissue ablation with minimal equipment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If radiofrequency catheter systems are used for circumferential ablation, then tissue ablation can be achieved, but the procedure becomes time-consuming and technically challenging with inconsistent results
Solution Approach 1:
The catheter is divided into multiple separate injector tubes (at least three) arranged circumferentially, each capable of independent injection. This segmentation allows each tube to be precisely positioned and controlled individually, improving the reproducibility of circumferential ablation while reducing the technical complexity compared to attempting to ablate the entire circumference simultaneously with a single catheter.
Solution Approach 2:
The injector tubes are pre-positioned in a collapsed state within the catheter body during delivery, then expanded at the target site to achieve precise circumferential placement. This preliminary positioning allows the system to be delivered easily through vasculature and then deployed in the exact configuration needed for ablation, reducing procedure time and improving reproducibility.
2Reliability
If RF energy is applied inside the renal artery for sympathetic nerve ablation, then hypertension can be treated, but complications such as restenosis, thrombosis, and embolization may occur
Solution Approach 1:
The system uses an ablative substance (such as ethanol or other chemically active agents) delivered through injector tubes as an intermediary to achieve nerve ablation. This chemical mediator allows for precise delivery to the target nerve tissue without the need for high-energy RF fields that cause thermal damage, thereby reducing complications such as restenosis, thrombosis, and embolization while maintaining treatment efficacy.
Solution Approach 2:
The invention replaces the mechanical/thermal RF energy delivery system with a chemical injection system. Instead of using RF catheters that generate heat to ablate tissue, the system injects ablative substances that chemically destroy nerve fibers. This substitution eliminates the harmful thermal effects while achieving the same therapeutic goal of sympathetic denervation for hypertension treatment.
3Manufacturing precision
If multiple RF catheters are used to ablate multiple pulmonary veins, then complete ablation can be achieved, but the procedure becomes elaborate and expensive requiring significant capital equipment
Solution Approach 1:
The system combines multiple injection functions into a single catheter assembly with multiple injector tubes that can be deployed simultaneously. This merging allows one catheter to perform the work of multiple separate RF catheters, achieving complete circumferential ablation of multiple pulmonary veins in a single procedure while eliminating the need for multiple separate catheter deliveries and reducing overall equipment complexity and cost.
Solution Approach 2:
The catheter system is designed with multi-functionality, capable of treating multiple pulmonary veins and potentially other vascular structures with a single device. The expandable injector tube assembly can be configured to address different anatomical targets, making the system universal rather than requiring specialized equipment for each specific ablation site, thereby reducing capital equipment requirements.
4Reliability
If RF ablation is performed to create sympathetic nerve denervation, then hypertension treatment can be achieved, but uneven or incomplete ablation may occur due to anatomic abnormalities or atherosclerotic disease
Solution Approach 1:
The injector tubes are designed to be expandable from a collapsed delivery configuration to an expanded treatment configuration. This dynamic transformation allows the system to adapt to different anatomical conditions and vessel diameters, ensuring that the injector tubes can be positioned uniformly around the target vessel regardless of anatomic variations or atherosclerotic changes, thereby achieving complete and uniform sympathetic nerve ablation.
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
Enables efficient and safe circumferential ablation of muscle and nerve fibers, reducing procedure time and radiation exposure while improving treatment efficacy for cardiac arrhythmias and hypertension, with potential for reduced complications and improved patient outcomes.
Implementation Method 1
Each tube includes an injector needle at its distal end. The injector needles are in fluid communication with an injection lumen in the catheter body
Implementation Method 2
There is a penetration limiting member proximal to the distal end of each needle so that the needles will only penetrate into the tissue of the ostial wall to a preset distance
Implementation Method 3
multiple expandable injector tubes arranged circumferentially around the body of the CAS near its distal end
Data Source
AI summary
At the present time, physicians often treat patients with atrial fibrillation (AF) using radiofrequency (RF) catheter systems to ablate conducting tissue in the wall of the Left Atrium of the heart around the ostium of the pulmonary veins. These systems are expensive and take time consuming to use. The present invention circular ablation system CAS includes a multiplicity of expandable needles that can be expanded around a central axis and positioned to inject a fluid like ethanol to ablate conductive tissue in a ring around the ostium of a pulmonary vein quickly and without the need for expensive capital equipment. The expansion of the needles is accomplished by self-expanding or balloon expandable structures. The invention includes centering means so that the needles will be situated in a pattern surrounding the outside of the ostium of a vein. Also included are members that limit the distance of penetration of the needles into the wall of the left atrium, or the aortic wall. The present invention also has an important application to ablate tissue around the ostium of one or both renal arteries, for the ablation of the sympathetic nerve fibers and/or other afferent or efferent nerves going to or from each kidney in order to treat hypertension.