Catheter Guide Wire Assembly Flow Resistance Optimization
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Solution Overview
Problem
Existing catheter and guide wire assemblies for intravascular blood pressure measurements face challenges in providing reliable and accurate signal quality, mechanical handling characteristics, and efficient flushing of blood from the lumen during PCI procedures, due to issues with signal damping and stiffness variations along the length.
Innovation Solution
A catheter and guide wire assembly with a tubular shaft, tubular extension, helical coil, and core member, featuring a low total flow-resistance index, anti-thrombogenic surfaces, and varying bending resistances along its length, designed to enhance torqueability, steerability, and facilitate efficient blood flushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the core member occupies a large portion of the inner lumen cross-sectional area, then the mechanical strength and structural stability are improved, but the fluid flow and pressure signal transmission are impeded
Solution Approach 1:
The patent applies parameter changes by optimizing the core member dimensions to occupy 10-40% of the inner lumen cross-sectional area, and by varying the wall thickness of the tubular shaft along its length. These parameter adjustments balance structural stability with adequate fluid flow capacity, resolving the contradiction between strength and fluid quantity.
2Ease of operation
If the catheter and guide wire assembly has high torsional rigidity and bending stiffness, then the mechanical handling and maneuverability are improved, but the signal transmission quality deteriorates due to damping
Solution Approach 1:
The patent applies local quality by providing different wall thicknesses at different locations of the tubular shaft. The distal portion has different wall thickness characteristics compared to the proximal portion, allowing optimized local mechanical properties for maneuverability while maintaining overall signal transmission quality through appropriate structural design.
3Reliability
If the inner lumen diameter is increased to improve pressure signal transmission, then the signal quality is improved, but the device outer diameter increases making it less suitable for intravascular use
Solution Approach 1:
The patent resolves this contradiction by optimizing multiple parameters simultaneously: the inner lumen diameter is set to 0.19-0.35mm for adequate signal transmission, while the outer diameter is constrained to 0.35-0.50mm through appropriate wall thickness selection and core member dimension optimization, maintaining both signal quality and intravascular compatibility.
4Stability of the object's composition
If the core member extends through the entire length of the tubular shaft, then the structural integrity is improved, but the fluid flow resistance increases
Solution Approach 1:
The patent applies parameter changes by limiting the core member length to extend only into the distal portion of the tubular shaft rather than its full length. This dimensional parameter adjustment maintains structural integrity where needed while preserving adequate fluid flow capacity in the proximal portion, resolving the contradiction between stability and fluid quantity.
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 assembly provides improved mechanical handling characteristics, enhanced signal quality, and efficient blood flushing, ensuring accurate blood pressure measurements and effective PCI procedures by optimizing the inner lumen dimensions and surface coatings.
Implementation Method 1
via a permeable, distal member, e.g. a coil, is in fluid connection with blood
Data Source
AI summary
A catheter and guide wire assembly for measurement of blood pressure in a living body, including a tubular shaft, which is connected to a tubular extension, which is connected to a permeable helical coil, which has a distal end that is secured in a distal tip, and a core member, which is attached in a distal portion of the tubular shaft and extends through the tubular extension and the helical coil, and is secured in the distal tip. The catheter and guide wire assembly has an outer diameter of about 0.35 mm and an open, inner lumen, which includes the tubular shaft, the tubular extension, the helical coil, and the core member. The catheter and guide wire assembly has a total flow-resistance index less than about 1.2×106 mm−3, and more preferably less than about 1.0×106 mm−3, and even more preferably less than about 0.7×106 mm−3.