Arteriovenous Graft Embedded Reinforcing Elements
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Solution Overview
Problem
Existing arteriovenous grafts used for hemodialysis often face complications due to weakening of blood vessels from repeated puncturing, necessitating a solution to extend the life of vascular access with minimal complications.
Innovation Solution
An arteriovenous graft with embedded reinforcing elements, made from biocompatible materials like PTFE, featuring surface features that prevent needle puncture and movement, is designed to inhibit needle penetration and enhance stability, comprising flexible and rigid portions for optimal placement and use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard arteriovenous graft is used for hemodialysis, then vascular access is established for blood filtration, but the blood vessels weaken over time due to repeated puncturing
Solution Approach 1:
The graft is divided into multiple segments with alternating flexible and rigid portions. The rigid portions contain reinforcing elements that prevent needle puncture, while the flexible portions allow natural movement and compliance. This segmentation resolves the contradiction by distributing the mechanical stress across different segments, preventing overall vessel weakening.
Solution Approach 2:
Different portions of the graft have different mechanical properties - rigid portions with reinforcing elements for puncture resistance and flexible portions for compliance. This local differentiation allows the graft to provide strength exactly where needed (at puncture sites) while maintaining flexibility in other areas, thus resolving the strength-reliability contradiction.
2Reliability
If reinforcing elements are embedded in the AV graft to prevent needle puncture, then needle movement is inhibited, but the device structure becomes more complex
Solution Approach 1:
The graft combines biocompatible polymeric material with reinforcing elements (such as metal or rigid polymer) to create a composite structure. The reinforcing elements are embedded within the flexible graft material, providing puncture resistance while maintaining overall graft flexibility. This composite approach resolves the contradiction by integrating multiple materials with complementary properties into a unified structure.
Solution Approach 2:
The graft uses a flexible biocompatible polymeric shell that encapsulates the reinforcing elements. This flexible shell maintains the graft's compliance and biocompatibility while the embedded reinforcing elements provide the necessary rigidity for puncture prevention. The flexible shell acts as a mediator that reconciles the conflicting requirements of flexibility and rigidity.
3Ease of operation
If the AV graft is made flexible for optimal placement, then ease of implantation is improved, but resistance to needle puncture is reduced
Solution Approach 1:
The graft is segmented into alternating flexible and rigid portions along its length. The flexible portions enable easy implantation and natural movement, while the rigid portions with reinforcing elements provide puncture resistance. This segmentation allows the graft to simultaneously exhibit both flexibility and strength in different locations, resolving the contradiction between ease of operation and puncture resistance.
Data Source
AI summary
An arteriovenous graft (AV graft) and method of using the AV graft to facilitate dialysis is described. The AV graft includes a tube having two or more embedded reinforcing elements that each extend along a length of the tube and extends circumferentially along a portion of the tube. The reinforcing element is positioned in the patent distal to the skin and assists by minimizing slippage of a hemodialysis needle that might happen to attempt to pierce the back side of the AV graft. The method includes providing the AV graft to the patient and providing hemodialysis to a patient provided with the AV graft.