Bifurcated Stent Assembly With Pre-Cannulation Passage
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Solution Overview
Problem
Current medical devices for treating bifurcated vessel lesions face challenges in preserving blood flow through both main and side branches, achieving sufficient radial strength to overcome calcified lesions, and maintaining flexibility to navigate vessel curvatures during delivery, while also being resistant to fracture and requiring a diameter difference between inflow and outflow vessels.
Innovation Solution
A bifurcated balloon-expandable stent catheter assembly comprising three interconnected stents with varying diameters, where the first and second stents are arranged along a longitudinal axis with a pre-cannulation means to accommodate a third stent, allowing for simultaneous deployment and maintaining flexibility to navigate tortuous anatomy, and a method involving a two-step balloon system for precise placement and expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single stent design is used to treat bifurcated vessel lesions, then the device structure is simple, but it cannot preserve blood flow through both main and side branches simultaneously
Solution Approach 1:
The stent is divided into multiple segments: a first stent portion for the main vessel and a second stent portion for the side branch, allowing independent deployment and blood flow preservation in both branches simultaneously
Solution Approach 2:
The second stent portion is nested within the first stent portion during delivery, with the distal portion of the second stent overlapping the proximal portion of the first stent, enabling compact delivery while maintaining functional separation
2Strength
If a stent with large diameter is used to overcome calcified lesions, then radial strength is sufficient, but flexibility to navigate vessel curvatures is reduced
Solution Approach 1:
The stent is segmented into multiple portions with different diameters - the first stent portion has a larger diameter for radial strength in the main vessel, while the second stent portion has a smaller diameter for flexibility in the side branch
Solution Approach 2:
Different portions of the stent have different diameters and structural properties optimized for their specific locations - the proximal portion has larger diameter for strength, while the distal portion has smaller diameter for adaptability
3Reliability
If multiple stents are used to treat bifurcated vessels, then blood flow preservation and radial strength are improved, but the risk of stent fracture increases
Solution Approach 1:
The second stent portion is nested within the first stent portion with overlapping segments, creating a continuous structural support that reduces stress concentration and fracture risk compared to separate stents
Solution Approach 2:
The stent is pre-cannulated during manufacturing to provide a passage from the interior of the second stent to the exterior of the first stent, allowing guidewire passage and reducing the need for additional interventions that could cause fracture
4Ease of operation
If a stent assembly is designed with pre-cannulation means, then guidewire passage and device navigation are improved, but the device complexity increases
Solution Approach 1:
The pre-cannulation means is integrated into the stent structure itself, merging the cannulation function with the stent framework rather than adding separate components
Solution Approach 2:
The stent is pre-cannulated during manufacturing to provide a ready-made passage for guidewires, eliminating the need for additional cannulation steps during the procedure
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 solution effectively treats bifurcated vessel lesions by preserving blood flow, providing sufficient radial strength, and maintaining flexibility, thereby addressing the limitations of existing devices in deliverability and strength, while ensuring the stent assembly can be accurately positioned and expanded within the bifurcation.
Implementation Method 1
an inflatable balloon mounted to the shaft at the distal end, the balloon having a distal portion having a first outer diameter and a proximal portion having a second outer diameter
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a medical device, the medical device comprising a balloon catheter, a first stent, and a second stent; the balloon catheter having a shaft and an inflatable balloon mounted to the shaft at the distal end the balloon having a distal portion having a first outer diameter and a proximal portion having a second outer diameter, wherein the first diameter is smaller than the second diameter and a transition region located between the distal portion and the proximal portion, a first stent having a first nominal diameter mounted on the distal portion of the balloon and a second stent having a second nominal diameter mounted on the proximal portion of the balloon, a distal portion of the second stent overlapping a proximal portion of the first stent, wherein the proximal end of the first stent is positioned proximal to the distal end of the second stent, the medical device further comprising a pre-cannulation means providing a passage from the interior of the second stent to the exterior of the first stent passing the stent overlapping portion between the inner surface of the second stent and the outer surface of the first stent.