Helical Coupling Sheath Mechanism for Vascular Constriction Crossing
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Solution Overview
Problem
Current techniques for crossing vascular constrictions during percutaneous vascular procedures often risk injury to the patient due to the need for substantial axial force, which can lead to vascular wall puncturing, and existing methods lack efficient mechanisms for navigating tortuous paths and constrictions.
Innovation Solution
A vascular constriction crossing mechanism featuring a first and second sheath with a helical coupling that converts torque to axial force, combined with an anchoring mechanism that resists displacement within the vascular structure, allowing for safe and effective advancement of a constriction crossing tip through vascular constrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If substantial axial force is applied to push a wire guide through a vascular constriction, then the wire guide can cross the constriction, but the risk of vascular wall puncturing increases
Solution Approach 1:
The patent replaces the conventional axial pushing mechanism with a rotational mechanical system. The helical coupling converts rotational motion of the outer sheath into axial advancement of the inner sheath and constriction crossing tip, allowing the tip to advance through the constriction via rotation rather than direct axial compression, thereby reducing vascular wall puncturing risk while maintaining crossing capability
Solution Approach 2:
The patent employs a helical (curved) coupling mechanism between the inner and outer sheaths. This helical structure converts rotational motion into axial motion, enabling the constriction crossing tip to advance through the constriction by rotating the outer sheath, which reduces the need for substantial axial force and thereby reduces the risk of vascular wall puncturing
2Productivity
If the wire guide is stiffened to enable crossing of the constriction, then the crossing capability improves, but the risk of patient injury increases
Solution Approach 1:
The patent employs a dynamic system where the inner sheath can rotate relative to the outer sheath through the helical coupling. This rotational degree of freedom allows the constriction crossing tip to advance through the constriction dynamically by rotating the outer sheath, rather than requiring the wire guide to be statically stiffened, thereby reducing patient injury risk while maintaining crossing capability
Solution Approach 2:
The patent divides the catheter into multiple segments: an inner sheath, an outer sheath, and a helical coupling connecting them. This segmentation allows independent rotation of the outer sheath to drive axial advancement of the inner sheath through the helical coupling, enabling constriction crossing without requiring the entire wire guide to be stiffened, thereby reducing patient injury risk
3Reliability
If a helical coupling mechanism is added to convert torque to axial force, then the safety and efficiency of constriction crossing improves, but the device complexity increases
Solution Approach 1:
The patent implements a nested structure where the inner sheath is positioned within the outer sheath, and the helical coupling connects them in a compact integrated manner. This nesting allows the helical coupling mechanism to be incorporated within the existing catheter structure without requiring separate external components, thereby improving constriction crossing safety while minimizing the increase in device complexity
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 mechanism enables safe and efficient crossing of vascular constrictions by converting rotational force into axial advancement, reducing the risk of vascular injury and facilitating the navigation of tortuous paths, thereby improving the success rate of percutaneous vascular procedures.
Implementation Method 1
a helical coupling between the first sheath and the second sheath. The helical coupling is configured to convert a torque on the proximal segment of one of the first sheath and the second sheath to an axial force on the first sheath for crossing a vascular constriction with the constriction crossing tip
Data Source
AI summary
A vascular procedure includes sliding a constriction crossing mechanism over a wire guide having a tip positioned at a proximal side of a constriction, and rotating a sheath of the mechanism about an axis relative another sheath of the mechanism. The method further includes helically engaging the sheaths, and guiding an intraluminal treatment device into or past the constriction. The mechanism includes a first sheath and a second sheath, and a tip coupled with the first sheath. The mechanism further includes a helical coupling between the first and second sheaths, which is configured to convert a torque on one of the sheaths to an axial force on the other of the sheaths for crossing a vascular constriction with the tip. An anchoring mechanism coupled with one of the sheaths includes a deployed state resisting displacement of the second sheath within a vascular structure of a patient.