Implantable Flow Restrictor with Biodegradable Linkages
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Solution Overview
Problem
Abrupt restoration of blood flow after an interventional procedure can cause reperfusion injury to downstream tissue due to sudden increases in oxidative and shear stresses, leading to damage and complications such as apoptosis.
Innovation Solution
An implantable medical device with a self-expanding annular member and biodegradable linkages that initially restrict and then gradually expand to allow controlled restoration of blood flow, transforming from a frustoconical to a cylindrical shape to prevent tissue overload, using biodegradable materials that dissolve over time to facilitate gradual expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blood flow is abruptly restored after an interventional procedure, then patency is restored to the blood vessel, but reperfusion injury occurs to downstream tissue due to sudden oxidative and shear stresses
Solution Approach 1:
The flow restrictor device transitions from a static flow restriction to a dynamic gradual expansion mechanism. The biodegradable linkages progressively dissolve over time, allowing the annular member to dynamically expand and increase blood flow incrementally. This dynamic transformation enables the device to adapt its flow restriction level as healing progresses, preventing sudden reperfusion injury while maintaining initial flow control.
Solution Approach 2:
The device utilizes parameter changes in the biodegradable linkage material over time. As the linkages degrade and dissolve, the structural parameters of the device change, transitioning from a constrained frustoconical shape to an expanded cylindrical shape. This parameter evolution controls the blood flow rate progressively, allowing tissue adaptation to increasing flow without abrupt changes that would cause reperfusion injury.
2Object-affected harmful factors
If a flow restrictor device is used to gradually restore blood flow, then reperfusion injury is prevented, but the device structure becomes more complex with additional components
Solution Approach 1:
The flow restrictor device merges multiple functions into a single integrated structure. The annular member combines flow restriction, gradual expansion capability, and structural support functions. The biodegradable linkages integrate the timing mechanism and expansion actuation without requiring separate control systems. This merging approach achieves gradual flow restoration while minimizing device complexity compared to mechanically controlled expansion systems.
Solution Approach 2:
The device employs self-service through the automatic biodegradation of the linkages. The material inherently degrades over time without requiring external intervention, surgical removal, or active control mechanisms. The dissolution process naturally drives the expansion sequence, eliminating the need for complex actuation systems while achieving the desired gradual flow restoration and reperfusion injury prevention.
3Duration of action of moving object
If the annular member is initially constrained to reduce blood flow, then tissue adaptation time is provided, but the constraining linkages must be temporary and require dissolution or removal
Solution Approach 1:
The biodegradable linkages utilize parameter changes in their material properties over time. The material transitions from an intact load-bearing state to a degraded dissolved state through controlled biodegradation. This parameter evolution provides the necessary temporary constraint duration for tissue adaptation while ultimately eliminating the need for surgical removal, as the linkages naturally dissolve after serving their flow control function.
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 device reduces the risk of reperfusion injury by allowing tissue to adapt to increasing blood flow, minimizing damage and complications by controlling the restoration of blood flow over time, thereby ensuring safer vascular recovery post-procedure.
Implementation Method 1
the linkages are biodegradable and dissolve in vivo
Implementation Method 2
the linkages are biodegradable and dissolve in vivo
Implementation Method 3
A self-expanding annular member is attached to the outlet
Data Source
AI summary
An implantable flow restrictor device is disclosed for initially restricting, then gradually restoring blood flow through a body vessel after an interventional procedure. A self-expanding annular member having a constricted diameter gives the device a frustoconical configuration that reduces blood flow therethrough upon initial deployment at a treatment site. The annular member is constricted by a plurality of linkages that operate to allow the annular member to gradually expand, thereby transforming the flow restrictor device to a cylindrical configuration that allows unimpeded blood flow therethrough. In one embodiment, expansion of the annular member is achieved via biodegradation of the linkages. In another embodiment, expansion of the annular member is achieved via creep deformation of the linkages. The flow restrictor device may be attached to an endoluminal prosthesis, or may be a separate complementary component that is delivered during an interventional procedure.