Subcutaneous Vascular Assemblies for Blood Flow
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Solution Overview
Problem
Individuals suffering from peripheral artery disease experience insufficient blood flow to extremities due to narrowed arteries, leading to conditions like critical limb ischemia and gangrene, with existing solutions failing to effectively address the issue of impaired blood circulation.
Innovation Solution
A medical device comprising a first graft portion, a second graft portion, and a catheter portion is implanted to create a non-natural flow path by attaching the graft portions to the vasculature above and below the knee, with the catheter portion positioned between them to enhance blood flow to the lower leg or feet, utilizing materials like porous PTFE and nitinol for strength and tissue integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vascular graft is used to bypass narrowed arteries, then blood flow to extremities is improved, but the graft is at risk of collapse and turbulence under compression forces
Solution Approach 1:
The vascular graft is constructed as a composite structure combining Dacron fabric layers with a flexible radiopaque element (such as nitinol mesh or coil) embedded within. This composite design provides both the biocompatibility and porosity of Dacron material and the mechanical strength and crush resistance of the nitinol framework, resolving the contradiction between maintaining blood flow stability and resisting compression forces.
Solution Approach 2:
The radiopaque reinforcement element is strategically positioned within specific regions of the graft where compression forces are most likely to occur, such as in the subcutaneous routing portion. This localized reinforcement provides strength where needed while maintaining the overall flexibility and blood flow characteristics of the graft in other regions.
2Ease of operation
If the catheter portion is made flexible for easy implantation, then ease of operation is improved, but the catheter is prone to collapse under external pressure
Solution Approach 1:
The catheter portion incorporates a flexible radiopaque element (nitinol mesh or coil) within its structure, creating a composite that maintains flexibility for easy implantation while providing structural support to prevent collapse under external compression forces during and after implantation.
3Duration of action of stationary object
If the graft portions are made permanent for long-term durability, then duration of action is improved, but replacement of the catheter portion becomes difficult
Solution Approach 1:
The vascular assembly is divided into distinct segments: permanent Dacron graft portions for long-term durability and a separate catheter portion that can be removed and replaced. The connectors allow for selective replacement of the catheter segment without disturbing the permanently implanted graft portions, resolving the contradiction between durability and ease of repair.
4Adaptability or versatility
If the graft material is made porous for tissue integration, then biocompatibility is improved, but structural strength is reduced
Solution Approach 1:
The graft combines porous Dacron fabric layers with a solid flexible radiopaque element (nitinol mesh or coil). The porous Dacron provides tissue integration and biocompatibility, while the nitinol framework provides the structural strength and crush resistance, resolving the contradiction between porosity for tissue integration and structural integrity.
Data Source
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AI summary
Medical devices and related method for improving blood flow to regions of a patient are described herein. Some medical devices may include a first graft portion, a second graft portion, and a catheter portion disposed between the first graft portion and the second graft portion. The medical device may be implanted into a patient to establish a non-natural flow path.