Superelastic Valve Clip for Atraumatic Mitral Repair
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Solution Overview
Problem
Current medical devices for treating mitral valve regurgitation, such as the MitraClip fixation device, are complex, stiff, and large, leading to trauma and premature degradation due to extreme deformation during deployment and use, and lack flexibility and multiple size options, posing safety risks and requiring general anesthesia.
Innovation Solution
A simpler, flexible fixation device with superelastic outer and inner arms that gently cinch the annulus, allowing for natural expansion and contraction, and a smaller catheter size, with a lock-less design and improved visualization techniques to facilitate minimally invasive procedures under local anesthesia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stiff fixation device with mechanical locking is used to securely grip valve tissue, then the gripping strength and reliability are improved, but the device complexity increases and the device becomes prone to premature degradation due to extreme deformation during deployment and bailout
Solution Approach 1:
The patent changes the material parameter from traditional stiff metals to shape-memory alloys (nitinol), which exhibit superelasticity. This allows the device to be flexible during deployment for easy positioning, then automatically lock into place through shape memory when actuated, providing reliable gripping without complex mechanical locking mechanisms. The superelastic material can undergo large deformations and return to its original shape, eliminating the need for extreme deformation during bailout.
Solution Approach 2:
The shape-memory alloy arms automatically lock into their gripping position through their inherent shape memory property when actuated, without requiring external mechanical locking mechanisms. The device serves itself by using the material's physical properties to achieve both deployment flexibility and gripping reliability through a single actuation event.
2Ease of operation
If a large catheter is used to deliver the fixation device to the treatment site, then the device can be properly positioned and deployed, but the trauma to the patient increases and the procedure requires general anesthesia
Solution Approach 1:
The device parameters are changed to achieve a compact, low-profile configuration for delivery. The shape-memory alloy arms can be collapsed into a small delivery catheter due to their flexibility in the unactuated state, allowing passage through smaller vessels without requiring large catheters that cause trauma and necessitate general anesthesia.
Solution Approach 2:
The device transitions dynamically from a compressed, flexible delivery configuration to an expanded, rigid gripping configuration upon actuation. This dynamic transformation allows the same device to pass through small catheters during delivery while providing stable gripping at the treatment site, eliminating the need for large catheters.
3Reliability
If the fixation device is made flexible to allow natural expansion and contraction of the annulus, then the physiological compatibility is improved, but the gripping strength and stability during the procedure may be compromised
Solution Approach 1:
The patent utilizes temperature-dependent phase changes in shape-memory alloys to switch between flexible and rigid states. At body temperature, the alloy is in a superelastic state that provides flexibility for physiological movement, but when actuated by a temperature change or mechanical stimulus, it rapidly transforms to a rigid state that provides strong gripping force, thus achieving both flexibility and strength as needed.
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 provides atraumatic tissue grasping and secure fixation with reduced trauma and risk of entanglement, enabling effective mitral valve repair with improved safety and reduced procedural risks, allowing for procedures under local anesthesia and using smaller catheters.
Implementation Method 1
the distal and proximal arms are formed of an elastic-plastic material or rheological material or shape-memory material configured to exhibit superelasticity in a physiological environment
Data Source
AI summary
A clip for immobilizing leaflets of a cardiac or venous valve includes a hub having a pair of tangle resistant spring-biased outer arms coupled to an inferior end of the hub and a pair of tangle resistant spring-biased inner arms adjacent to the outer arms and coupled to a superior end of the hub. A delivery catheter may be used to position the valve clip adjacent a target valve while the outer and inner arms are biased in an opened position relative to each other. After the valve leaflets are located between the opened outer and inner arms, the biasing forces may be released to allow the clip to self-close the clip over the valve leaflets.