Rotational Atherectomy Drive Shaft Low-Speed Control

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Solution Overview

Problem

Existing rotational atherectomy systems lack control over unsustained rotational speed and direction, leading to unwanted friction, tissue damage, and inefficient plaque removal due to spring-back action in drive shafts.

Innovation Solution

A rotational atherectomy device with a motor or turbine capable of slow, non-sustained rotation (less than 50,000 rpm) and controlled rotational direction, using a spin-to-open or spin-to-close drive shaft design to minimize friction and improve tracking, with a microprocessor-controlled PWM system for speed and direction management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high rotational speed is used for plaque removal, then plaque removal efficiency is improved, but friction and tissue damage increase

Engineering Contradiction:

Improveplaque removal efficiencyVSAvoidfriction and tissue damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The drive shaft is designed to rotate periodically between forward and reverse directions at controlled low speeds, creating intermittent motion that prevents continuous friction and tissue wrapping while maintaining plaque removal capability through periodic abrasive contact

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically changes rotational speed parameters from high speed to very low speed (less than 50,000 rpm), and changes rotational direction periodically, allowing the drive shaft to maintain plaque removal effectiveness while minimizing friction and tissue damage through parameter modulation

Inventive Principle:

Principle #35Parameter changes

2Productivity

If sustained high rotational speed is used, then plaque removal efficiency is improved, but drive shaft tracking and friction control deteriorate

Engineering Contradiction:

Improveplaque removal efficiencyVSAvoiddrive shaft tracking

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The rotational driver implements periodic forward and reverse rotation cycles at controlled low speeds, allowing the drive shaft to periodically engage and disengage from the guide wire, which maintains tracking accuracy while preventing continuous friction and enabling periodic repositioning

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system transitions from static high-speed rotation to dynamic low-speed bidirectional rotation, allowing real-time adjustment of rotational direction and speed to maintain optimal drive shaft tracking and minimize friction during the atherectomy procedure

Inventive Principle:

Principle #15Dynamics

3Speed

If spring-back action occurs in drive shaft, then rotational speed recovery is improved, but tissue wrapping and vessel damage increase

Engineering Contradiction:

Improverotational speed recoveryVSAvoidtissue wrapping and vessel damage

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The rotational driver applies preliminary counter-rotation in the opposite direction before spring-back occurs, preventing tissue wrapping and vessel damage by actively counteracting the spring-back motion that would otherwise cause harmful effects

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system uses periodic forward and reverse rotation to prevent continuous spring-back action, allowing controlled speed variations that maintain rotational speed recovery while preventing the uncontrolled spring-back that causes tissue wrapping and vessel damage

Inventive Principle:

Principle #19Periodic action

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 solution reduces friction and tissue wrapping, enhances plaque removal efficiency by allowing controlled low-speed and direction changes, preventing vessel damage and improving the tracking of the drive shaft during procedures.

Implementation Method 1

A rotational atherectomy device with a motor or turbine capable of slow, non-sustained rotation

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

using a spin-to-open or spin-to-close drive shaft design to minimize friction and improve tracking

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

an abrasive element attached thereto

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentUS10702300B2Methods, devices and systems for slow rotation of drive shaft driven atherectomy systems

Publication Date: 2020.07.07 CARDIOVASCULAR SYSTEMS INC

AI summary

The present system is directed in various embodiments to methods, devices and systems for rotational atherectomy procedures. More specifically, embodiments comprise a rotational driver with rotational drive shaft and abrasive element attached thereto, the rotational driver being controlled by the rotational controller to rotate at unsustained low rotational speeds and/or rotational direction.