Venous Filter Detachment Mechanism Using Shape Memory Alloy
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Solution Overview
Problem
Current vena cava filters lack a detachment and retrieval mechanism that allows for longer-term temporary placement and subsequent removal, limiting flexibility in embolic protection and requiring multiple systems for central venous access and filter deployment.
Innovation Solution
A central access venous filter (CAVF) system with a detachment mechanism featuring a catheter body and a moveable outer sheath, where the filter member is coupled to the catheter body via a shape memory material that transitions between states to enable detachment and retrieval, allowing for both embolic protection and central line access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent filter is placed in the vena cava, then embolic protection is provided, but the filter cannot be retrieved and may cause long-term complications
Solution Approach 1:
The filter system transitions from a static permanent filter to a dynamic system with two states: deployed (attached to catheter body) and retrieved (detached from catheter body). The detachment mechanism enables the filter to change its attachment state, providing both permanent protection and retrieval capability.
Solution Approach 2:
The detachment mechanism utilizes shape memory material that changes its mechanical properties in response to temperature changes. The material transitions between a first state (at body temperature) where it allows detachment, and a second state (at elevated temperature) where it secures attachment, enabling controlled state changes.
2Adaptability or versatility
If a retrievable filter is designed with detachment mechanisms, then flexibility for removal is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical detachment systems with a thermally-responsive shape memory material system. Instead of using intricate mechanical locks, springs, or actuation mechanisms, the detachment is achieved through temperature-induced phase changes in the shape memory material, simplifying the overall device structure.
Solution Approach 2:
The shape memory material performs the detachment function automatically in response to temperature changes without requiring complex external actuation mechanisms. The material self-adjusts its properties to enable or prevent detachment based on thermal conditions, reducing the need for additional control systems.
3Reliability
If separate systems are used for central venous access and filter deployment, then each function can be optimized, but the overall procedure requires multiple devices and increases operational complexity
Solution Approach 1:
The patent combines the central venous access catheter and the vena cava filter into a single integrated system. The filter is attached to the catheter body, allowing both central line access and embolic protection functions to be performed by one device, eliminating the need for separate deployment procedures.
Solution Approach 2:
The catheter-filter system serves multiple functions: it provides central venous access for fluid administration, serves as a delivery system for filter deployment, and provides embolic protection. The single system performs what would traditionally require multiple separate devices and procedures.
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
Enables flexible placement and retrieval of the vena cava filter, providing extended embolic protection while maintaining central venous access, and simplifying the process by using a single system for both deployment and retrieval.
Implementation Method 1
The first end comprises a collar made of a shape memory material that is immovably coupled to the catheter body in a first state and movably coupled to the catheter body upon transition to a second state
Data Source
AI summary
A detachment and retrieval mechanism for a central venous access filter includes a catheter body, and an outer sheath concentrically disposed about the catheter body. The outer sheath and the catheter body are moveable relative to one another. A filter member includes a first end coupled to the catheter body and a second end movable relative to the catheter body. The first end may have a collar that is immovably coupled to the catheter body in a first state and movably coupled to the catheter body upon transition to a second state.