Shock Wave Catheter Arc Preconditioning

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Solution Overview

Problem

Current systems for treating calcified lesions in arteries using shock wave generators face issues with excessive energy release, leading to tissue damage and balloon stress due to unpredictable energy delivery and electrode material degradation from high voltage pulses.

Innovation Solution

A catheter system with a power source that applies a low voltage for 2 milliseconds to pre-grow a bubble, followed by a short high voltage pulse to generate shock waves, controlling the energy release and reducing heat generation and balloon stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high voltage pulses are applied to electrodes to generate shock waves for breaking calcified plaque, then the calcified lesion is effectively treated, but excessive energy release causes tissue damage and balloon stress

Engineering Contradiction:
Improveeffectiveness of calcified plaque treatmentVSAvoidtissue damage and balloon stress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A low voltage pulse (100-500 volts) is applied before the high voltage pulse to pre-grow a bubble at the electrode. This preliminary bubble formation reduces the energy required for the subsequent high voltage pulse to generate the shock wave, thereby preventing excessive energy release and tissue damage while maintaining effective plaque treatment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the voltage parameter in two stages: first applying a low voltage (100-500 volts) to grow the bubble, then applying a controlled high voltage pulse (2000-10000 volts) to generate the shock wave. This parameter change sequence optimizes energy delivery, reducing harmful effects while maintaining treatment effectiveness

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the same amount of energy is used for each arc to ensure bubble formation, then reliable arcs are produced, but excessive energy causes fluid heating and balloon stress

Engineering Contradiction:
Improvearc formation reliabilityVSAvoidfluid temperature elevation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The low voltage pulse applied before each high voltage pulse pre-grows a bubble of appropriate size, ensuring reliable arc formation without requiring excessive energy. This preliminary action makes the subsequent high voltage pulse more efficient, reducing energy waste and fluid heating while maintaining consistent arc production

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system replaces direct high voltage arc initiation with a two-stage process involving low voltage bubble growth followed by controlled high voltage discharge. This substitution allows precise control over energy delivery, ensuring reliable arcs while minimizing excessive heating of the fluid

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If high voltage pulses are applied to break calcified plaque, then the lesion is opened, but electrode material is removed limiting the number of usable pulses

Engineering Contradiction:
Improvelesion opening capabilityVSAvoidelectrode material degradation
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

By pre-growing bubbles with low voltage pulses before applying high voltage, the system reduces the total energy required for each shock wave generation. This decreases the erosive effect on electrode material, extending electrode lifespan and allowing more treatment pulses without significant material loss

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The two-stage voltage approach (low voltage bubble growth followed by controlled high voltage discharge) optimizes the energy delivery parameters. This reduces the cumulative material removal from electrodes while maintaining effective shock wave generation for lesion opening

Inventive Principle:
Principle #35Parameter changes

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

This approach allows for controlled energy delivery, minimizing tissue damage and balloon stress while effectively breaking up calcified plaques without excessive pressure, extending the lifespan of the electrodes.

Implementation Method 1

a low voltage is applied across the electrodes for 2 milliseconds to pre-grow a bubble

Methodology Applied
Scientific EffectBubble formation: Bubble

Implementation Method 2

Each high voltage pulse causes an arc to form across the electrodes

Methodology Applied
Scientific EffectElectrical arc: Electric Arc

Implementation Method 3

Each arc results in intense heat and energy for a brief period of time

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

a shock wave is formed that propagates through the fluid and impinges upon the wall of the balloon and the calcified region

Methodology Applied
Scientific EffectShock wave: Shock Wave

Data Source

PatentEP2884911B1Shock wave catheter system with arc preconditioning
Publication Date: 2016.06.22 SHOCKWAVE MEDICAL INC
  • EP2884911B1 patent drawingFigure 1~2
  • EP2884911B1 patent drawingFigure 3~5
  • EP2884911B1 patent drawingFigure 6~7

AI summary

A shock wave catheter system and method produces a shock wave with reduced energy. The system includes a catheter and a power source. The catheter has an elongated carrier and a balloon about the carrier in sealed relation thereto. The balloon is arranged to receive a fluid therein that inflates the balloon. The catheter further includes an arc generator including at least two electrodes within the balloon. The power source is coupled to the at least two electrodes and is configured to grow a bubble at one of the at least two electrodes and then thereafter to rapidly expand the bubble to form a shock wave within the balloon.