Subrounded Ultrasonic Ablation Catheter for Renal Denervation
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Solution Overview
Problem
Conventional catheters for renal sympathetic denervation lack precision in targeting renal sympathetic nerves, leading to potential nerve self-restoration, excessive denervation, and complications such as renal artery stenosis and thrombosis, due to inadequate ablation techniques and lack of nerve distribution identification.
Innovation Solution
An ultrasound ablation catheter with a cylindrical body, featuring laterally arranged ultrasound treatment transducers spaced ≥1cm apart, an ultrasound imaging transducer between them, and a control handle for unidirectional rotation, emitting non-focusing acoustic beams to achieve sub-rounded ablation without focusing, thereby preventing nerve self-restoration and preserving sympathetic nerve tracts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a short electrode or wafer is used for ablation, then the risk of blood vessel injury and ablation complications is reduced, but the sympathetic nerve fiber may self-restored after operation, adversely affecting long-term therapeutic effect
Solution Approach 1:
The ablation electrode is designed as a long structure extending along the renal artery, segmented into multiple active ablation zones spaced at specific intervals (e.g., 5-10mm apart). This segmentation allows the electrode to cover a sufficient length of the artery to prevent nerve self-restoration while maintaining safe energy distribution to avoid concentrated damage to any single blood vessel segment.
2Reliability
If an overlong ablation electrode or wafer is used, then the sympathetic nerve fiber self-restoration is prevented, but the released energy is greatly enhanced, which may increase a risk of the blood vessel being injured and an ablation complication
Solution Approach 1:
The electrode incorporates varying properties along its length, with active ablation zones positioned at specific locations where sympathetic nerves are most densely distributed. The spacing and energy output of each segment are optimized locally to match the anatomical distribution of nerves, ensuring effective denervation while minimizing unnecessary energy release in areas with fewer nerves, thus reducing blood vessel injury risk.
3Reliability
If circumferential ultrasound ablation is employed to achieve complete sympathetic denervation, then a complete denervation effect is obtained, but excessive sympathetic denervation may occur, decreasing stress ability of the patient and aggravating damage to the intima of the renal arteries
Solution Approach 1:
Instead of applying circumferential ablation uniformly around the entire renal artery, the catheter delivers ultrasound energy to only specific angular sectors (e.g., 180-270 degrees) at selected locations along the artery. This partial ablation approach targets the predominant sympathetic nerve distribution while deliberately preserving nerves in other sectors, achieving effective denervation without excessive destruction of all sympathetic innervation, thus maintaining patient stress ability and reducing intima damage.
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
The catheter provides stable and controlled sympathetic denervation, preventing nerve self-restoration and minimizing vascular injury, while allowing for precise renal-nerve ablation and maintaining body homeostasis.
Implementation Method 1
ultrasound treatment transducers spaced ≥1cm apart... emitting non-focusing acoustic beams
Implementation Method 2
energy acts on sympathetic nerve fibers on a vascular adventitia and in an adipose tissue via a vascular intima, thereby decreasing a sympathetic tone
Data Source
Figure 1~2
Figure 3~4
AI summary
An ultrasonic ablation catheter comprises a catheter body (1), an ultrasonic treatment energy converter set (2), an ultrasonic imaging energy converter set (3), a control handle (4) and an energy converter interface (5). The catheter body (1) is of a cylindrical structure; the ultrasonic treatment energy converter set (2) is disposed on the lateral surface of the far end of the catheter body (1), is of a sheet shape or an unclosed ring shape and can emit line-shaped or subrounded ultrasonic beams. The crossing distance between every two adjacent ultrasonic treatment energy converters (21) is more than or equal to 1 cm. Each ultrasonic imaging energy converter (31) is positioned between every two adjacent ultrasonic treatment energy converters (21). The control handle (4) is disposed at the near end of the catheter body (1). The energy converter interface (5) comprises a first interface (51) and a second interface (52). After sympathetic nerve fibers are ablated by the ablation catheter, the nerve fibers can be cut into sections which are not continuous mutually and are completely separated in the middle; moreover, the coverage distance between the ultrasonic treatment energy converters (21) is long (more than or equal to 1 cm), so that mutual chemotaxis and self repair of the completely separated nerve fibers are avoided and stability of an effect of removing the sympathetic nerve fibers is improved.