Balloon Inflation Rate Control via Pressure Attenuator
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Solution Overview
Problem
Fast inflation rates during stent deployment can lead to uneven expansion, strut damage, and increased likelihood of restenosis due to kinetic effects and material properties of both metallic and bioresorbable stents, particularly polymers, which are susceptible to fractures under rapid deformation.
Innovation Solution
A system with a pressure attenuator, such as a fluid accumulator, is used to control the inflation rate of the balloon by varying the chamber volume in response to pressure, allowing a biasing force to modulate the pressure increase, ensuring a controlled and slower expansion of the stent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast inflation rate is used during stent deployment, then procedural time is reduced and productivity is improved, but stent expansion uniformity deteriorates and strut damage increases
Solution Approach 1:
A fluid accumulator chamber is introduced as an intermediary device between the inflation source and the balloon. The chamber accumulates inflation fluid and releases it at a controlled rate, mediating between the fast inflation demand and the slow expansion requirement. This allows rapid fluid delivery while maintaining controlled balloon inflation pressure and rate.
Solution Approach 2:
The invention changes the pressure parameter dynamics by using an accumulator chamber that decouples pressure buildup from volume delivery. The chamber allows pressure to build rapidly while controlling the rate of volume transfer to the balloon, effectively separating the pressure generation phase from the expansion phase.
2Speed
If fast inflation rate is used, then deployment speed is improved, but stent recoil increases and deployment reliability deteriorates
Solution Approach 1:
The fluid accumulator acts as a mediator that buffers the kinetic effects of rapid inflation. By accumulating fluid at high pressure and releasing it gradually, the system achieves fast deployment initiation while maintaining controlled expansion rates that prevent stent recoil and ensure reliable deployment.
Solution Approach 2:
The accumulator chamber provides beforehand cushioning by pre-storing inflation fluid under pressure. This allows the system to rapidly respond to deployment needs while the chamber's compliance cushions pressure fluctuations, preventing sudden pressure spikes that could cause stent recoil or damage.
3Productivity
If rapid inflation is used for polymer scaffolds, then procedural efficiency is improved, but material stress increases and strut fracture risk increases
Solution Approach 1:
The fluid accumulator serves as a protective intermediary for the polymer scaffold. It delivers inflation fluid rapidly to the system but controls the actual pressure application to the scaffold, preventing excessive stress concentrations that could cause strut fracture while maintaining procedural efficiency.
Solution Approach 2:
The invention changes the rate parameter of pressure application. By decoupling fluid delivery rate from pressure application rate through the accumulator chamber, the system can efficiently deliver fluid while applying pressure at a rate that prevents polymer material stress exceedance and strut fracture.
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 prevents strut damage and ensures uniform stent deployment, reducing the risk of restenosis by maintaining consistent expansion speed and minimizing material stress, particularly beneficial for bioresorbable polymer scaffolds.
Implementation Method 1
a biasing element associated with the movable containing wall that applies a biasing force opposing an increase in the volume of the chamber
Implementation Method 2
a pressure attenuator for controlling an inflation rate of the balloon, the pressure attenuator comprising a chamber connected with the inflation lumen of the catheter, wherein a movable containing wall of the chamber allows the volume of the chamber to vary in response to pressure of inflation fluid
Data Source
AI summary
An apparatus and method for controlling inflation pressure and pressurization rate of a balloon during deployment of a stent or scaffold are disclosed. The apparatus and method involve a pressure attenuator for controlling an inflation rate of the delivery balloon.