Gradually-Expandable Stent for Pediatric Heart Valve Growth
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Solution Overview
Problem
Conventional stents used in the Ross Procedure for heart valve replacement do not grow with the patient, necessitating additional surgical procedures to replace them, which poses risks and may lead to adverse outcomes.
Innovation Solution
A gradually-expandable stent design featuring a base ring and uprights with expansion features that enlarge the central valve-accepting area in response to patient growth over an extended period, allowing the stent to accommodate increasing valve annulus size without the need for repeated surgeries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional fixed-size stent is used, then the stent provides immediate structural support for the pulmonary autograft, but the stent does not grow with the patient, necessitating additional surgical procedures
Solution Approach 1:
The stent incorporates expansion features including telescoping sections and bellows structures that allow the stent to dynamically expand over time. The base ring can increase in diameter from an initial size to a maximum size, accommodating patient growth without requiring additional surgical interventions.
Solution Approach 2:
The stent design allows for parameter changes in its dimensional characteristics. The expansion features enable the stent to transition from a compressed delivery state through intermediate expansion states to a final expanded state, with the base ring diameter capable of increasing by approximately 20-50% over time as the patient grows.
2Adaptability or versatility
If additional surgical procedures are performed to replace the stent as the patient grows, then the stent size can be adjusted, but the patient is exposed to unwanted surgical risks and potential adverse outcomes
Solution Approach 1:
The stent is designed as a single implantable device with built-in expansion capability that eliminates the need for multiple surgical procedures. The gradual expansion mechanism allows the stent to grow with the patient over time, avoiding repeated surgical exposures and their associated risks.
3Adaptability or versatility
If a gradually-expandable stent is used, then the stent can accommodate patient growth over time, but the stent structure becomes more complex with expansion features
Solution Approach 1:
The stent incorporates nested telescoping sections where inner rings are positioned within outer rings, allowing for compact packaging during delivery while enabling gradual expansion to a larger final configuration. The bellows structures are nested within the overall stent framework, providing expansion capability without excessive external complexity.
Solution Approach 2:
The stent is divided into multiple segments including a base ring, multiple telescoping sections, and bellows structures. Each segment can expand independently or in coordination with others, allowing the overall stent to grow while maintaining structural integrity and manageable complexity in each individual component.
Data Source
AI summary
A gradually-expandable stent includes a base ring completely encircling a central valve-accepting area. A plurality of uprights is provided. Each upright includes two longitudinally extending upright struts. Each upright strut has a strut base directly connected to the base ring and a strut tip directly attached to the other strut tip of the upright strut at a rounded upright apex. The upright apex is longitudinally spaced from the base ring. At least one expansion feature is associated with the base ring and gradually expands to enlarge the central valve-accepting area toward a maximum valve-accepting area responsive to growth of the patient over an extended dwell time.