Shape-Memory Annuloplasty Ring for Delayed Tricuspid Resizing
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Solution Overview
Problem
Existing treatments for tricuspid valve regurgitation, such as transcatheter valve replacement and annuloplasty procedures, face challenges including the risk of blood clotting, embolism, and the need for invasive surgery, while percutaneous annuloplasty rings are complex and time-consuming with mixed clinical success.
Innovation Solution
An annuloplasty ring system with a shape-memory frame and biodegradable connectors that gradually reduces the tricuspid valve annulus diameter after secure implantation, utilizing a skirt for tissue ingrowth and a sizing device for shape adaptation, allowing for transcatheter implantation without immediate size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transcatheter replacement valve is implanted in a large dilated annulus, then the tricuspid valve regurgitation is treated, but the risk of blood clotting and embolism increases due to foreign material in low-flow areas
Solution Approach 1:
The annulus is resized before valve implantation through annuloplasty procedure. The ring is implanted first to reshape and reduce the annulus diameter, creating a smaller, more appropriate geometry for subsequent valve deployment. This preliminary action ensures that the replacement valve will be positioned in an optimized environment that promotes proper blood flow patterns and reduces thrombosis risk.
Solution Approach 2:
The treatment is divided into two distinct phases: first the annuloplasty ring is implanted to resize the annulus, then the replacement valve is deployed in the remodeled geometry. This segmentation allows each component to perform its specific function optimally without the complications that arise from implanting a large valve in a dilated annulus.
2Shape
If a rigid annuloplasty ring is sutured during open heart surgery, then the annulus is forced to resize and reshape, but the procedure becomes highly invasive
Solution Approach 1:
The traditional mechanical suture-based annuloplasty performed during open heart surgery is replaced with a transcatheter-delivered self-expanding or balloon-expandable ring system. The ring is delivered through catheters via the femoral vein and deployed in the right atrium, eliminating the need for sternotomy, cardiopulmonary bypass, and direct surgical manipulation of the annulus.
Solution Approach 2:
A delivery catheter system serves as an intermediary to transport the annuloplasty ring from the external environment to the implantation site within the heart. The catheter allows percutaneous access and precise positioning of the ring without requiring open surgical exposure of the annulus.
3Ease of operation
If a percutaneous annuloplasty ring is implanted, then invasive surgery is avoided, but the procedure becomes highly complex and time consuming with mixed clinical success
Solution Approach 1:
The annuloplasty ring and the replacement valve are combined into a single integrated implantable assembly. The ring is positioned first to resize the annulus, then the valve is deployed within the same catheter delivery system, consolidating two separate procedures into one coordinated intervention that reduces overall procedural complexity and time.
Solution Approach 2:
The annuloplasty ring is deployed first as a preliminary step to prepare the annulus geometry, creating an optimized foundation for subsequent valve implantation. This staged approach within a single procedure simplifies the overall process by establishing the correct anatomical configuration before introducing the valve component.
4Reliability
If a prosthetic heart valve is implanted in a large annulus, then tricuspid valve regurgitation is treated, but the frame inhibits desirable remodeling of the right ventricle
Solution Approach 1:
The annulus is resized and reshaped through annuloplasty before the replacement valve is implanted. This preliminary remodeling of the annular geometry creates a smaller, more normal configuration that allows the right ventricle to remodel favorably over time, while still providing a stable platform for the prosthetic valve to function effectively.
Solution Approach 2:
The treatment addresses the annular pathology and the valve replacement as separate but coordinated steps. By first correcting the annular dilation and then implanting the valve in the remodeled geometry, the solution allows physiological ventricular remodeling to occur while maintaining reliable valve 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 system effectively reduces tricuspid valve regurgitation by gradually resizing the annulus over months, enhancing leaflet coaptation and avoiding invasive surgery, with biocompatibility and flexibility minimizing complications.
Implementation Method 1
The frame may be formed of a shape-memory material and may be shape-set to a final condition in which the frame has a final diameter. The plurality of biodegradable connectors may maintain the frame in an initial condition having an initial diameter, the initial diameter being larger than the final diameter.
Implementation Method 2
The frame may be configured to transition from the initial condition to the final condition upon degradation of the biodegradable sutures. The biodegradable sutures may be configured to maintain the frame in the initial condition for more than about one month following implantation of the annuloplasty ring into a patient.
Implementation Method 3
the skirt 160a, and thus the frame 120a, become more and more securely fixed to the native valve annulus. Preferably, the connectors 140a are selected so that they do not significantly degrade until significant tissue ingrowth has occurred and the frame 120a and skirt 160a are very securely fixed to the native annulus.
Data Source
AI summary
An annuloplasty ring system may include an annuloplasty ring. The annuloplasty ring may include a frame having a plurality of cells, the plurality of cells forming a circumferential ring. The annuloplasty ring may also include a skirt coupled to a bottom surface of the frame, and a plurality of biodegradable connectors, each of the plurality of biodegradable connectors connecting two portions of a corresponding one of the plurality of cells. The frame may be formed of a shape-memory material and may be shape-set to a final condition in which the frame has a final diameter. The plurality of biodegradable connectors may maintain the frame in an initial condition having an initial diameter, the initial diameter being larger than the final diameter.