Locus Emitter Shock Wave Catheter for Flexibility and Longevity
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Solution Overview
Problem
Existing shock wave catheters for treating calcified lesions have issues with a large crossing profile, reduced flexibility, and decreased longevity due to erosion and degradation of electrodes under high voltage pulsing.
Innovation Solution
The catheter design incorporates an emitter wire with gaps forming shock wave emitters, using durable materials like molybdenum or tungsten, and a carrier wire with higher conductivity, such as copper, connected by electrical joints to enhance flexibility and longevity, reducing the crossing profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrode designs are used in shock wave catheters, then shock wave generation capability is achieved, but the electrodes suffer from erosion and degradation under high voltage pulsing, reducing catheter longevity
Solution Approach 1:
The patent employs a sacrificial emitter wire made of durable material (molybdenum, tungsten, or rhodium) that can be replaced after a limited number of shock wave generation cycles. This emitter wire is positioned within a replaceable electrode assembly that can be swapped out when degraded, eliminating the need to replace the entire catheter. This approach directly addresses electrode erosion by accepting that the emitter will degrade and providing an economical replacement strategy.
Solution Approach 2:
The patent uses composite construction for the electrode assembly, combining a durable emitter wire (molybdenum, tungsten, or rhodium) with a conductive carrier wire (copper, aluminum, or stainless steel). This composite structure allows the emitter to be made of erosion-resistant material while the carrier wire provides high electrical conductivity. The combination resolves the contradiction between durability and conductivity.
2Ease of operation
If emitter bands with inner and outer electrodes are used, then shock wave generation is achieved, but the crossing profile increases and flexibility decreases
Solution Approach 1:
The patent removes the inner electrode and insulating sleeve components from the traditional emitter band design, retaining only the outer electrode as a simplified ring-shaped emitter. This extraction of unnecessary components significantly reduces the crossing profile and improves catheter flexibility while maintaining shock wave generation capability through the simplified outer electrode structure.
Solution Approach 2:
The patent segments the emitter into discrete ring-shaped outer electrodes positioned at intervals along the catheter shaft, rather than using continuous emitter bands. This segmentation allows for reduced local complexity at each emitter location, improving flexibility without compromising overall shock wave generation effectiveness.
3Ease of operation
If rigid emitter structures are used, then structural stability is maintained, but deliverability of the catheter is reduced
Solution Approach 1:
The patent applies local quality by making the emitter wire and carrier wire assemblies replaceable only at the distal emitter end, while maintaining structural integrity of the remaining catheter shaft. This allows the catheter to be flexible for delivery but maintains stability where needed, as the rigid emitter components are concentrated only at the treatment site and can be replaced if degraded.
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 new design achieves increased flexibility, reduced crossing profile, and extended longevity of the catheter, allowing for more effective and safer treatment of calcified lesions with improved sonic output.
Implementation Method 1
The calcified plaque modification is achieved by creating acoustic shock waves within the catheter by an electrical discharge across the electrodes. This discharge creates one or more rapidly expanding vapor bubbles that generate the acoustic shock waves.
Implementation Method 2
These shock waves propagate radially outward and modify calcified plaque within the blood vessels.
Implementation Method 3
a laser pulse is transmitted into and absorbed by a fluid within the catheter. This absorption process rapidly heats and vaporizes the fluid
Implementation Method 4
This absorption process rapidly heats and vaporizes the fluid, thereby generating the rapidly expanding vapor bubble, as well as the acoustic shock waves
Implementation Method 5
the acoustic pressure from the shock waves can crack and disrupt lesions near the angioplasty balloon without harming the surrounding tissue
Data Source
AI summary
An exemplary shock wave catheter system comprises: a catheter body comprising a lumen; an emitter wire configured to generate shock waves, wherein one or more gaps are formed between two or more portions of the emitter wire along a length of the catheter body, each of the one or more gaps forming a locus emitter; a carrier wire configured to conduct electricity to the emitter wire; and one or more electrical joints configured to electrically couple and join the emitter wire and the carrier wire.