Annealed Catheter Wire Segment for Kink Resistance
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Solution Overview
Problem
Current introducer sheaths face challenges with vascular access bleeding after removal and kinking issues due to thin walls, which can block access to the vascular system and affect medical instrument fit.
Innovation Solution
The introduction of an introducer sheath with a coiled wire frame that includes an annealed segment at the distal portion, where the wire is disposed more densely, helps maintain the shape and reduces kinking, while the annealed segment reduces residual stresses and prevents unraveling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the wall thickness of the introducer sheath is reduced to minimize trauma during insertion, then insertion trauma is reduced, but the sheath becomes prone to kinking and loss of shape retention
Solution Approach 1:
The patent employs a composite construction combining a thin-walled sheath with an internal coiled wire frame reinforcement. The wire frame acts as a structural skeleton that maintains the sheath's shape and prevents kinking while allowing the outer wall to remain thin for reduced insertion trauma. This composite approach allows the sheath to achieve both flexibility for easy insertion and structural integrity for shape retention.
2Ease of operation
If the wall thickness of the introducer sheath is reduced to facilitate easy removal from the puncture site, then removal ease is improved, but vascular access bleeding increases due to poor shape retention
Solution Approach 1:
The thin-walled sheath combined with the internal wire frame reinforcement allows the sheath to be easily removed while maintaining its shape. The wire frame prevents the sheath from collapsing or deforming during removal, ensuring that the puncture site maintains its integrity and minimizing bleeding risks associated with poor shape retention.
3Stability of the object's composition
If the wire frame is made entirely from annealed wire to prevent unraveling, then coil stability is improved, but the wire frame loses spring temper and becomes prone to kinking
Solution Approach 1:
The patent applies different heat treatment states to different segments of the wire frame. The distal portion (tip area) is annealed to prevent unraveling and maintain coil stability where the wires are most susceptible to separation. The proximal portion (body area) retains spring temper to provide resistance against kinking and maintain overall shape. This localized differentiation of material properties resolves the contradiction between coil stability and kink resistance.
4Strength
If the wire frame is made entirely from unannealed wire to maintain spring temper, then resistance to kinking is improved, but the coil becomes prone to unraveling at the distal portion
Solution Approach 1:
The wire frame is constructed with a gradient of material properties where the proximal portion maintains unannealed spring temper for kink resistance, while the distal portion is annealed to prevent unraveling. This localized heat treatment approach allows each segment of the wire frame to optimize its function for the specific mechanical demands of its location.
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 design effectively reduces vascular access bleeding by maintaining the integrity of the sheath shaft and preventing kinking, ensuring consistent access to the vascular system without the need for frequent replacements.
Implementation Method 1
electrodes secured to two pulleys in a catheter coil winding system may be activated to apply a charge or voltage to a segment of reinforcing wire extending between the two pulleys just before the segment of reinforcing wire is coiled around a liner or elongate member. Applying the charge to the segment of reinforcing wire heats the segment of reinforcing wire effective to anneal the segment of reinforcing wire.
Implementation Method 2
The annealed segment of the reinforcing wire may form at least some of a distal portion of a coiled wire frame. This annealed segment reduces a tendency of the coiled wire frame to unravel along the annealed portion
Data Source
AI summary
The present disclosure describes systems and methods of annealing segment of a reinforcing coil of a catheter shaft. A method includes providing a liner and annealing a segment of a reinforcing wire such that the segment is between two unannealed regions of the reinforcing wire. The method also includes, after annealing the segment of the reinforcing wire, coiling the reinforcing wire over the liner to form a wire frame having a distal portion and a proximal portion. The wire is disposed more densely in the distal portion than in the proximal portion, and the segment of the reinforcing wire that is annealed is at least proximate to the distal portion of the wire frame. The method also includes securing a jacket over the wire frame and the liner.