Expandable Catheter for Circumferential Vessel Wall Injection
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Solution Overview
Problem
Current technologies for treating cardiac arrhythmias and hypertension through ablation of muscle cells and nerve fibers are inefficient, challenging to perform reproducibly, and pose safety risks due to thermal injuries, incomplete ablation, and radiation exposure, with existing catheter systems being expensive and requiring significant capital equipment.
Innovation Solution
The Vascular Nerve Ablation System (VNAS) employs multiple expandable injector tubes with needles that penetrate only a preset distance into the vessel wall, allowing for circumferential ablation of nerve fibers and muscle cells using ethanol or other ablative fluids, reducing the need for expensive equipment and minimizing tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiofrequency catheter systems are used to ablate tissue, then ablation of conducting tissue can be achieved, but thermal injury to surrounding tissue occurs and significant capital equipment is required
Solution Approach 1:
The patent replaces the radiofrequency thermal ablation system with a mechanical injection system that delivers ablative substances (ethanol, phenol, or other neurotoxic agents) directly to the target tissue. This substitution eliminates the need for expensive RF generation systems and fluid handling equipment while avoiding thermal injury to surrounding tissues. The injection system uses a simple catheter with injection ports that can be positioned against the vessel wall to deliver the ablative substance locally.
Solution Approach 2:
The patent employs a disposable catheter system rather than expensive reusable RF equipment. The catheter is a single-use device that can be easily inserted and removed, eliminating the need for capital-intensive RF generation systems, fluid handling systems, and other expensive equipment. This approach significantly reduces the cost of the procedure while maintaining effective ablation capability through the use of chemical ablative agents.
2Manufacturing precision
If RF catheters ablate one focus at a time, then precise ablation can be achieved, but the procedure becomes technically challenging and very time consuming
Solution Approach 1:
The catheter is divided into multiple segments or sections, each with its own injection port positioned at different locations along the catheter body. This segmentation allows simultaneous or sequential injection of ablative substance at multiple sites around the vessel circumference, enabling complete circumferential ablation in a single procedure rather than requiring multiple sequential ablations at different focal points.
Solution Approach 2:
The patent combines multiple injection ports into a single catheter device, allowing simultaneous delivery of ablative substance to multiple target sites. This merging of functions into one device enables complete circumferential ablation to be achieved in a single catheter insertion and positioning event, dramatically reducing procedure time while maintaining the precision needed for targeted nerve fiber ablation.
3Reliability
If current technologies are used for circumferential ablation around pulmonary veins, then complete ablation can be achieved, but very long fluoroscopy and procedure times lead to high radiation exposure and increased stroke risk
Solution Approach 1:
The patent replaces the RF thermal ablation system with a chemical injection system that delivers ablative substances directly to the target tissue. This substitution eliminates the need for prolonged fluoroscopy monitoring required with RF systems, thereby reducing radiation exposure to both patients and operators. The chemical ablation process is faster and requires less continuous imaging surveillance.
Solution Approach 2:
The catheter is designed with multiple pre-positioned injection ports that are already oriented to deliver ablative substance circumferentially around the vessel. This preliminary positioning and orientation of injection ports eliminates the need for prolonged fluoroscopy-guided adjustments and maneuvers during the procedure, reducing radiation exposure while ensuring complete circumferential coverage is achieved efficiently.
4Reliability
If RF energy is applied within the renal artery for sympathetic nerve denervation, then nerve ablation can be achieved, but thermal injury may lead to restenosis, thrombosis, and embolization
Solution Approach 1:
The patent replaces the RF thermal energy system with a chemical injection system that delivers neurotoxic agents directly to the sympathetic nerve fibers in the renal artery wall. This substitution avoids the thermal injury mechanisms that cause restenosis, thrombosis, and embolization. The chemical ablative agents (ethanol, phenol, or other neurotoxic substances) selectively destroy nerve fibers without causing the thermal damage to the vessel wall and surrounding tissues that characterizes RF ablation.
5Reliability
If RF energy is applied to ablate nerves, then sympathetic nerve denervation can be achieved, but uneven delivery of RF energy due to anatomic abnormalities leads to incomplete ablation
Solution Approach 1:
The catheter is segmented into multiple injection ports distributed circumferentially around the catheter body. This segmentation ensures that ablative substance is delivered to multiple sites around the vessel circumference, providing uniform coverage even when the vessel has irregular anatomy, calcifications, or atherosclerotic plaques that would cause uneven RF energy distribution. Each injection port independently delivers the neurotoxic agent directly to the vessel wall at its specific location.
Solution Approach 2:
The injection ports are designed to deliver ablative substance locally and directly to the target tissue at each specific site around the vessel. This localized delivery ensures that each segment of the vessel wall receives adequate amounts of the neurotoxic agent regardless of variations in vessel wall thickness, calcification, or atherosclerotic disease. The local quality of the injection system allows tailored delivery to address anatomic abnormalities while maintaining overall uniformity of nerve denervation.
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
VNAS enables efficient and reproducible ablation of nerve fibers and muscle cells, reducing procedure time, radiation exposure, and the risk of complications, while allowing for precise control of ablation zones, thus improving treatment outcomes for cardiac arrhythmias and hypertension.
Implementation Method 1
multiple expandable injector tubes with needles that penetrate only a preset distance into the vessel wall, allowing for circumferential ablation of nerve fibers and muscle cells using ethanol or other ablative fluids
Data Source
AI summary
A vascular nerve ablation (denervation) system includes a multiplicity of expandable needles which open around a central axis to engage the wall of a blood vessel allowing the injection of a cytotoxic or neurotoxic solution for ablating conducting tissue in and near the vessel wall of a renal artery or pulmonary vein. The expandable needles are formed of self-expanding materials and include structures which limit the distance of penetration of the injection needles into the tissue of the wall of the blood vessel.