Dog-Bone Balloon Catheter Annular Tear Prevention
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Solution Overview
Problem
Current balloon valvuloplasty catheters face challenges such as difficulty in expanding and returning to original shape, causing vascular trauma, limited control over expansion diameter, potential rupture, and inadequate restoration of aortic valve flexibility, leading to complications like annular tear, restenosis, and mechanical injury to cardiac tissues.
Innovation Solution
A dog-bone-shaped balloon catheter with a semi-compliant waist and non-compliant bulbous regions, designed to self-center on the aortic annulus, providing controlled dilation and accurate measurement of annulus diameter, reducing the risk of annular dissection and improving valve leaflet flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If polymeric balloon catheters are used to achieve high pressures at fixed diameter, then effective valve dilation is improved, but the ability to return to pre-expansion configuration is worsened
Solution Approach 1:
The balloon transitions from a static fixed-diameter design to a dynamic variable-diameter design that can adapt its shape during inflation and deflation cycles, enabling both high pressure delivery and shape recovery through controlled material deformation
Solution Approach 2:
The balloon material properties are changed to allow variable compliance, transitioning from rigid fixed-diameter polymeric material to a material that can dynamically adjust its mechanical properties to achieve both high pressure expansion and shape recovery
2Stress or pressure
If non-distensible plastic balloons are used to achieve high pressures, then therapeutic effectiveness is improved, but the risk of vascular trauma is worsened
Solution Approach 1:
The rigid non-distensible plastic balloon is replaced with a flexible thin-film balloon that can conform to vascular anatomy, reducing mechanical stress concentration and minimizing vascular trauma while maintaining therapeutic pressure delivery
Solution Approach 2:
The mechanical properties of the balloon material are changed from rigid non-distensible to flexible distensible, allowing the balloon to adapt to vessel walls and reduce trauma while still achieving necessary expansion pressures for valve dilation
3Manufacturing precision
If oversized balloons are used for aggressive predilation, then valve preparation is improved, but the risk of annular tear is worsened
Solution Approach 1:
The balloon transitions from a static oversized design to a dynamic design that can be precisely controlled during inflation, allowing progressive expansion that prepares the valve without exceeding safe pressure thresholds that would cause annular tear
Solution Approach 2:
The balloon system incorporates feedback mechanisms (pressure sensors, compliance monitoring) that provide real-time information about valve resistance and balloon expansion, allowing dynamic adjustment of inflation pressure to achieve optimal valve preparation while preventing annular tear
4Object-affected harmful factors
If undersized balloons are used for predilation, then annular tear risk is reduced, but valve preparation effectiveness is worsened
Solution Approach 1:
The balloon transitions from a static undersized design to a dynamic design that can progressively increase in size during the procedure, starting with a smaller profile to minimize trauma then expanding to achieve adequate valve preparation
Solution Approach 2:
The balloon is designed to perform preliminary gentle expansion first to prepare the annulus, then progressively increase size to achieve optimal valve preparation, rather than attempting full expansion in a single step
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 dog-bone-shaped balloon catheter effectively dilates aortic valve leaflets with controlled pressure, minimizing the risk of annular dissection and restenosis, while maintaining accurate positioning and perfusion during the procedure, enhancing the safety and efficacy of valvuloplasty.
Implementation Method 1
The waist region is formed with a semi-compliant material... As the balloon is inflated, the waist region expands to a diameter that contacts the aortic annulus
Implementation Method 2
Each of the proximal and distal end regions is formed with a non-compliant material... These regions maintain a fixed diameter that is larger than the waist diameter
Implementation Method 3
The balloon is then inflated to dilate the diseased valve opening... increases in fluid pressure within the balloon produce very little change in balloon diameter
Data Source
AI summary
A valvuloplasty catheter has a dog-bone shaped balloon with semi-compliant smaller diameter waist and non-compliant larger diameter bulbous end regions. The balloon centers across the valve with the waist adjacent to the annulus. One bulbous region serves to hyperextend the valve leaflets and the other assists in stabilizing the balloon position to reduce migration. The semi-compliant waist increases in diameter as fluid enters the balloon until it comes into contact with the valve annulus. The pressure within the balloon per unit of volume delivery has a greater slope after contact with the annulus than before resulting in a change in slope for the pressure versus volume curve. The diameter of the balloon and annulus are determined at this inflection point when the balloon contacts the annulus.