3D Adjustable Annuloplasty Ring for Precise Mitral Valve Sizing
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Solution Overview
Problem
Current annuloplasty rings face challenges in achieving precise sizing during mitral valve repair procedures, leading to complications such as residual mitral regurgitation and systolic anterior motion due to imprecise sizing, necessitating potential reoperation on-pump to adjust the annulus size.
Innovation Solution
An adjustable 3D mitral annuloplasty ring system with a ratcheting mechanism and elastic-plastic inner core, allowing for real-time adjustments on a beating heart to optimize the annular size and shape, using a delivery system with adjustment filaments and tension adjusters to fine-tune the AP diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed-size annuloplasty ring is implanted during mitral valve repair, then the surgical procedure is simpler and faster, but the sizing precision is insufficient leading to residual mitral regurgitation or systolic anterior motion
Solution Approach 1:
The annuloplasty ring is designed with dynamic adjustability, allowing the AP diameter to be modified after implantation. The ring includes adjustment mechanisms such as cables, pulleys, or shape memory alloy elements that enable real-time resizing under echocardiographic guidance, transforming a static device into a dynamic one that adapts to actual valve function
Solution Approach 2:
The ring's geometric parameters, specifically the AP diameter, can be changed post-implantation through external adjustment mechanisms. This allows modification of the ring's dimensional parameters based on observed valve performance, enabling precise customization without requiring device replacement
2Reliability
If the annuloplasty ring size is reduced to improve leaflet coaptation, then mitral regurgitation is reduced, but the risk of systolic anterior motion increases
Solution Approach 1:
The adjustment mechanism incorporates real-time feedback through echocardiographic monitoring during the adjustment process. This allows the surgeon to observe the effect of each adjustment on valve function and reverse or modify adjustments if adverse effects like SAM are observed, enabling safe optimization of coaptation
Solution Approach 2:
The ability to dynamically adjust the ring size allows for incremental modifications rather than committing to a fixed size reduction. This dynamic approach enables the surgeon to find the optimal balance between improving coaptation and avoiding SAM by making small, reversible adjustments
3Productivity
If the surgeon makes an educated guess on ring size during implantation, then the procedure is completed efficiently, but the risk of poor repair outcome increases
Solution Approach 1:
The ring is pre-adjusted to a preliminary size during implantation based on standard sizing protocols, allowing the surgery to proceed efficiently. Subsequent fine-tuning adjustments are made after the patient is weaned from bypass, combining the benefits of efficient initial implantation with reliable post-operative optimization
Solution Approach 2:
Real-time echocardiographic feedback during the post-bypass adjustment period allows the surgeon to objectively assess repair quality and make data-driven adjustments rather than relying solely on preoperative estimates, significantly improving outcome reliability
4Ease of operation
If a larger annuloplasty ring is implanted to maintain annular perimeter, then the surgical procedure is simpler, but leaflet coaptation is insufficient leading to residual mitral regurgitation
Solution Approach 1:
The ring allows for post-implantation reduction of the AP diameter to achieve proper leaflet coaptation while maintaining the surgical simplicity of initial implantation. The dynamic adjustment capability enables the ring to transition from a larger implantation size to an optimized smaller functional size
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 precise customization of the annuloplasty ring size and shape post-implantation, reducing the need for reoperation and minimizing complications by allowing adjustments under direct visualization, thus improving surgical outcomes.
Implementation Method 1
an inner core formed of an elastic-plastic material
Implementation Method 2
The anterior and posterior segments define a ratchet mechanism at overlapped regions on opposite sides
Data Source
Figure 1~2
Figure 3A~3E
Figure 4
AI summary
An annuloplasty ring for repair of mitral valves whose shape can be altered remotely to perform post-implant size and/or shape adjustments. On version of the annuloplasty ring has a size-adjustable remodeling inner core within an outer suture-permeable interface for attaching the ring to an annulus. The inner core has an arcuate anterior segment that overlaps an arcuate posterior segment on opposite sides, with the segments being shaped in three dimensions to conform to the mitral annulus. The overlapping sides may have a ratchet mechanism with teeth on one engaging a detent on the other, or mating undulating bumps that can be adjusted in increments. A pair of adjustment filaments that pass through a delivery system and through channels in one segment may act on the other segment to adjust the peripheral shape of the annuloplasty ring.