Balloon Catheter Retractable Sheath Length Adjustment
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Solution Overview
Problem
Current balloon catheters lack the ability to adjust length effectively and securely, leading to potential damage to surrounding tissue, ineffective treatments, and premature activation of drug coatings due to exposure to intravascular fluids.
Innovation Solution
A balloon catheter with a retractable sheath and locking mechanism that allows for adjustable length and a mechanical stop to prevent balloon escape, along with a watertight seal to maintain the drug coating until the treatment site, and recapture elements for efficient repacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a balloon catheter is made too long to cover larger treatment areas, then it can treat more extensive blockages, but it may damage surrounding tissue and requires stocking multiple sizes
Solution Approach 1:
The balloon catheter incorporates a retractable sheath that allows the balloon length to be dynamically adjusted during the procedure. The sheath can be retracted to expose different lengths of the balloon, enabling the operator to adapt the effective treatment length to match the specific blockage size, thereby treating extensive blockages when needed while avoiding tissue damage when a shorter exposure is sufficient.
2Adaptability or versatility
If a retractable sheath is added to allow length adjustment, then variable length control is achieved, but the device complexity increases
Solution Approach 1:
The design nests the balloon within a sheath, where the sheath acts as a protective covering that can be retracted. This nested configuration allows the balloon to be stored in a compact state within the sheath during delivery, then exposed to the required length during the procedure. The nesting principle enables length adjustment functionality while maintaining a relatively simple overall structure that can be delivered through standard catheter delivery systems.
3Strength
If the balloon is allowed to extend freely from the sheath during inflation, then full expansion is achieved, but the balloon may escape the sheath entirely due to internal pressure and shape
Solution Approach 1:
The sheath is designed to remain in place over the balloon during the inflation process, acting as a preliminary constraint that prevents the balloon from escaping. The sheath maintains the balloon's position and controls its extension before and during inflation, ensuring that the balloon expands only to the intended length and remains stable throughout the procedure despite internal pressure.
4Ease of manufacture
If the balloon is exposed to intravascular fluids during insertion, then drug coating can be applied to the outer surface, but premature activation and loss of drug coating occurs
Solution Approach 1:
The balloon with its drug coating is nested within the sheath during insertion and delivery. The sheath acts as a protective barrier that isolates the drug-coated balloon surface from direct contact with intravascular fluids until the balloon reaches the treatment zone. This nesting configuration allows the drug coating to be applied to the outer surface for ease of manufacture while preventing premature activation, elution, dilution, and loss of the drug coating during insertion and delivery.
Data Source
AI summary
An intravascular balloon catheter device includes an outer member disposed about an inner member. A balloon has a proximal portion which is connected to the outer member and a distal portion which is connected to the inner member. A sheath is disposed about the outer member and adapted for movement relative to the balloon. A coating with a therapeutic agent is provided on at least the distal portion of the balloon. The distal portion fits snugly into the sheath so as to provide a substantially watertight engagement therebetween when inside the sheath. The sheath is configured to prevent the proximal portion of the balloon from inflating to a diameter larger than the sheath.