Balloon Expandable Stent Inducing Spiral Flow
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Solution Overview
Problem
Existing balloon expanded stent delivery systems face challenges in consistently imparting a spiral shape to stents during deployment, which is necessary to induce spiral flow and reduce thrombosis and restenosis, as modifying balloons and stents with helical constraints is problematic for mass production.
Innovation Solution
A balloon expanded stent delivery system that includes a balloon mounted on a catheter with a spirally wound inflation constraint, which constrains the balloon to a spiral shape upon inflation, imprinting a matching spiral contour on the stent, allowing the stent to retain the flow directing surface after deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If helical plastic strips are attached to the balloon surface to create spiral flow, then spiral flow is induced and thrombosis is reduced, but manufacturing complexity increases and mass production becomes problematic
Solution Approach 1:
The patent removes the complex helical plastic strips from the system and replaces them with a simple wire constraint mechanism attached to the catheter, extracting the problematic component while preserving the spiral flow function
Solution Approach 2:
The patent introduces a wire constraint as an intermediary element between the catheter and the balloon, which indirectly shapes the balloon into a spiral configuration during inflation, avoiding direct modification of the balloon surface
2Reliability
If helical constraints are modified on stents to produce spiral flow, then thrombosis is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The wire constraint is pre-formed with the desired spiral geometry before deployment, and this pre-formed constraint automatically imprints the spiral shape on the stent during balloon inflation, eliminating the need for complex post-manufacturing adjustments
Solution Approach 2:
The wire constraint acts as a physical template or mold that copies its spiral geometry onto the balloon and subsequently onto the stent, ensuring consistent spiral contours without requiring high-precision manufacturing of each individual stent
3Shape
If the balloon is constrained to a spiral shape during inflation, then a spiral contour is imprinted on the stent, but the balloon requires additional constraint structures
Solution Approach 1:
The wire constraint is a flexible, thin element that can conform to the balloon surface while maintaining its spiral geometry, providing the necessary constraint without adding bulky or complex structures
Solution Approach 2:
The wire constraint serves multiple functions: it maintains catheter stability, shapes the balloon into a spiral configuration, and imprints the spiral contour on the stent, eliminating the need for separate constraint mechanisms
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 system effectively induces spiral flow, increasing sheer stress at the stent surface, potentially reducing thrombosis and restenosis, while using conventional stents and balloon catheters with minimal modifications, offering adaptability and cost-effectiveness.
Implementation Method 1
a wire attached to the catheter and spirally wrapped on the balloon... the wire constrains the inflated balloon to a spiral shape
Data Source
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AI summary
A balloon expanded stent delivery system includes an inflation constraint, such as a wire, spirally wound about the longitudinal axis in contact with a balloon and attached to an underlying catheter. A balloon expanded stent is mounted about the balloon and the inflation constraint. The delivery system has a predeployment configuration with the balloon deflated and the stent unexpanded. The system has a deployment configuration in which the inflation constraint constrains the inflated balloon to a spiral shape, the stent is expanded and in contact with the balloon, and the stent has a flow directing surface with a spiral contour that matches the spiral shape of the balloon. In a postdeployment configuration, the stent retains the flow directing surface with the spiral contour.