Nested Stent Kit for Adjustable Blood Flow Reduction
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Solution Overview
Problem
Current stents for reducing pulmonary blood flow are not adjustable after implantation, limiting their effectiveness in managing conditions like Eisenmenger's syndrome and pulmonary hypertension, particularly in developing countries where surgical interventions are not feasible.
Innovation Solution
A kit of stents comprising a first reduction stent with a narrowed section and an expandable dilatation stent, along with a second reduction stent, allows for adjustable blood flow by altering the cross-sectional area within the stent, enabling adjustments even months or years after implantation through the insertion of dilatation or second reduction stents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed stent is implanted to reduce pulmonary blood flow, then blood flow reduction is achieved, but the stent cannot be adjusted after implantation limiting effectiveness
Solution Approach 1:
The patent employs nested stents where an inner adjustable stent is placed within an outer fixed stent. The inner stent can be independently manipulated to adjust the blood flow cross-section without removing the outer stent, enabling post-implantation adjustment while maintaining the structural support of the fixed outer stent.
Solution Approach 2:
The inner stent is designed with dynamic adjustment capabilities, allowing the blood flow cross-section to be modified after implantation. This dynamic feature enables the system to adapt to changing patient needs and physiological conditions, transforming a static blood flow reduction system into a dynamic one.
2Reliability
If surgical pulmonary artery banding is performed to reduce pulmonary blood flow, then blood flow reduction is achieved, but the procedure is not feasible in many developing countries
Solution Approach 1:
The patent replaces the complex surgical mechanical system (open-heart surgery with pulmonary artery banding) with a less invasive interventional system using catheter-based stent implantation. This substitution reduces the technical complexity and resource requirements, making the procedure feasible in developing countries without specialized surgical centers.
Solution Approach 2:
The stent system acts as an intermediary device that achieves blood flow reduction without requiring direct surgical manipulation of the pulmonary artery. The stent provides a minimally invasive alternative that bridges the gap between complex surgery and simple banding procedures.
3Ease of operation
If the stent cross-section is fixed at implantation, then implantation simplicity is maintained, but adjustments cannot be made months or years later
Solution Approach 1:
The stent system is segmented into an outer fixed stent and an inner adjustable stent. The outer stent provides stable, simple implantation, while the inner stent offers long-term adjustability. This segmentation allows each component to fulfill its specific function independently, combining simplicity with extended adjustability.
Solution Approach 2:
The outer stent is implanted first to establish the structural framework, followed by the inner stent that enables future adjustments. This preliminary action of implanting the outer stent creates a stable base that facilitates subsequent adjustments without complicating the initial implantation procedure.
4Device complexity
If a single stent design is used, then device complexity is reduced, but adaptability to different blood flow requirements is limited
Solution Approach 1:
The inner stent serves multiple functions: it can be adjusted to different diameters, removed if needed, and allows for future interventions. This multi-functionality compensates for the increased number of components, as the inner stent performs several roles that would otherwise require multiple different devices.
Data Source
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AI summary
A kit of stents for adjustable interventional reduction of blood flow in a blood vessel, the kit comprising : a first reduction stent (20) having in an expanded conformation at least one widened section (21) and a narrowed section (22), the narrowed section defining a central lumen (4) providing reduced fluid communication between an upstream end (2') and a downstream end (1') of the first reduction stent (20); at least one expandable dilatation stent (30) having a tubular form insertable into and expandable in the central lumen (4) of the first reduction stent (20) in order to define an enlarged central lumen (34); at least one second reduction stent (40) having a narrowed tubular section (43) insertable into the central lumen (4) of the first reduction stent (20) or the central lumen (34) of the dilatation stent (30) in order to define an reduced central lumen (44), and having anchoring means (41) at its upstream end. The invention further relates to an adjustable multi-lumen stent for interventional reduction of blood flow in a blood vessel.