Intravascular Nerve Ablation System Circumferential Fluid Delivery
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Solution Overview
Problem
Current technologies for ablating muscle cells and nerve fibers, such as RF catheter systems, face challenges in achieving reproducible and efficient circumferential ablation around renal arteries, leading to complications like renal artery stenosis, thrombosis, and incomplete nerve denervation, due to limitations in delivering ablative energy uniformly and safely.
Innovation Solution
The Intravascular Nerve Ablation System (INAS) employs a disposable catheter with multiple expandable injector tubes and sharpened needles that allow for simultaneous circumferential injection of ablative fluid around the renal artery, minimizing intimal and medial layer injury, and featuring a penetration limiting mechanism to ensure precise and adjustable depth of needle penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF catheter systems are used for ablation, then nerve fibers can be ablated, but thermal injury to surrounding tissue and renal artery stenosis occur
Solution Approach 1:
The patent replaces thermal energy delivery (RF ablation) with mechanical energy delivery (balloon expansion and microjet fluid injection). The expandable balloon mechanically delivers ablative fluid through microjets directly to the adventitial plane, avoiding thermal diffusion to surrounding tissues while achieving effective nerve ablation through controlled fluid delivery.
Solution Approach 2:
The patent introduces an expandable balloon as an intermediary device between the catheter and the renal artery wall. The balloon serves as a mechanical mediator that expands to contact the arterial wall and delivers ablative fluid through microjets, providing controlled, localized delivery without direct thermal contact that causes tissue injury.
2Reliability
If RF energy is applied within the renal artery, then sympathetic nerve denervation can be achieved, but renal artery spasm, thrombosis, and restenosis occur
Solution Approach 1:
The patent substitutes thermal energy delivery with mechanical fluid delivery through an expandable balloon. The balloon expands to contact the arterial wall and delivers ablative fluid through microjets, achieving nerve denervation through mechanical/chemical means rather than thermal energy, thereby avoiding vessel spasm and thrombosis associated with RF heating.
Solution Approach 2:
The patent extracts the ablative function from thermal energy delivery and isolates it to specific microjet outlets on the balloon surface. By concentrating fluid delivery at discrete points through microjets rather than diffuse thermal energy, the system achieves targeted nerve ablation without causing widespread vascular injury, spasm, or thrombosis.
3Reliability
If circumferential RF ablation is performed, then complete nerve denervation can be achieved, but transmural thermal injury and renal artery stenosis occur
Solution Approach 1:
The patent applies local quality by concentrating ablative fluid delivery at the outer surface (adventitial plane) of the renal artery through microjets on the expanded balloon. This localized delivery achieves complete circumferential nerve denervation at the target site without causing transmural thermal injury, as the fluid is delivered precisely where needed without diffuse thermal spread.
Solution Approach 2:
The patent replaces circumferential thermal energy delivery with mechanical fluid delivery through microjets on an expandable balloon. The balloon expands to provide circumferential contact and delivers ablative fluid through multiple microjet outlets, achieving complete nerve denervation through controlled fluid injection rather than thermal energy, thereby avoiding transmural injury.
4Reliability
If multiple RF catheters are used for circumferential ablation, then complete denervation can be achieved, but procedure time and radiation exposure increase
Solution Approach 1:
The patent merges multiple ablation functions into a single expandable balloon device. The balloon incorporates multiple microjet outlets arranged circumferentially, allowing simultaneous delivery of ablative fluid around the entire renal artery circumference in one deployment, eliminating the need for multiple sequential RF catheter interventions and reducing procedure time and radiation exposure.
Solution Approach 2:
The patent transitions from linear/sequential ablation delivery to three-dimensional circumferential delivery by expanding the balloon radially outward to contact the renal artery wall around its entire circumference. This dimensional change allows simultaneous multi-point fluid delivery in all directions, achieving complete denervation in a single step rather than requiring multiple sequential catheter positions.
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
INAS enables efficient and reproducible circumferential ablation of nerve fibers, reducing the risk of complications and improving treatment outcomes for cardiac arrhythmias, hypertension, and congestive heart failure by ensuring uniform and precise delivery of ablative agents, while minimizing tissue damage.
Implementation Method 1
the distal portions of which are expandable and, when expanded, press outwardly against the inside wall of a target vessel
Implementation Method 2
coaxial injection needles in fluid communication with an injection lumen to allow injection of an ablative fluid into the outer layers of the renal artery
Data Source
AI summary
A catheter-based/intravascular ablation (denervation) system includes a multiplicity of needles which expand open around a central axis to engage the wall of a blood vessel, or the wall of the left atrium, allowing the injection of a cytotoxic or/or neurotoxic solution for ablating conducting tissue, or nerve fibers around the ostium of the pulmonary vein, or circumferentially in or just beyond the outer layer of the renal artery. The expandable needle delivery system is formed with self-expanding materials and include structures, near the end portion of the needles, or using separate guide tubes. The system also includes means to limit and/or adjust the depth of penetration of the ablative fluid into the tissue of the wall of the targeted blood vessel. The preferred embodiment of the catheter delivered through the vascular system of a patient includes a multiplicity of expandable guide tubes that engage the wall of a blood vessel. Injection needles having injection egress at or near their sharpened distal end are then advanced through the guide tubes to penetrate the wall of the blood vessel to a prescribed depth. The ability to provide PeriVascular injection so as to only affect the outer layer(s) of a blood vessel without affecting the media has particular application for PeriVascular Renal Denervation (PVRD) of the sympathetic nerves which lie in the adventitia or outside the adventitia of the renal artery.