Implantable Flow Control Cuff for Cardiac Cycle Synchronization
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Solution Overview
Problem
Current aortic-to-pulmonary shunts in pediatric patients with congenital heart disease face challenges in managing excessive pulmonary blood flow, leading to systemic circulation issues and low coronary perfusion, with existing solutions failing to effectively regulate the pulmonary to systemic flow ratio (Qp/Qs) during the cardiac cycle.
Innovation Solution
An implantable medical device with a flow control cuff comprising a stiff outer wall and a deformable inner wall, modulated by a pump and controller, which adjusts its diameter in sync with the cardiac cycle to constrict or relax the shunt, thereby controlling blood flow and maintaining optimal Qp/Qs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a smaller shunt size is used to reduce run-off, then diastolic run-off is reduced, but overall pulmonary blood flow is also reduced
Solution Approach 1:
The patent employs a dynamic flow control device that can change its resistance properties in real-time based on the cardiac cycle phase. The device transitions from a static shunt to an active system that modulates resistance between systole and diastole, allowing optimal pulmonary blood flow during systole while preventing run-off during diastole.
Solution Approach 2:
The device changes the resistance parameter dynamically throughout the cardiac cycle. During systole, resistance is lowered to maximize pulmonary blood flow; during diastole, resistance is increased to prevent run-off. This parameter modulation resolves the contradiction between maintaining flow and preventing backflow.
2Quantity of substance
If shunt size is increased to allow more flow to the lungs during systole, then pulmonary blood flow is improved, but diastolic run-off increases
Solution Approach 1:
The dynamic control mechanism allows the shunt to adapt its resistance based on cardiac phase, enabling a larger effective shunt size during systole for improved pulmonary flow while automatically restricting flow during diastole to prevent run-off.
Solution Approach 2:
The device operates in periodic cycles synchronized with the heartbeat, alternating between high-flow and low-resistance states during systole and high-resistance states during diastole. This periodic modulation enables the shunt to accommodate larger sizing without permanent run-off issues.
3Device complexity
If passive shunt design is used, then device complexity is reduced, but ability to regulate Qp/Qs ratio is insufficient
Solution Approach 1:
The flow control device autonomously regulates the Qp/Qs ratio by sensing cardiac cycle phase and automatically adjusting resistance without requiring external intervention. The system self-regulates based on intrinsic physiological signals, providing adaptive control while maintaining relatively simple implantation.
4Ease of manufacture
If fixed resistance shunt is used, then manufacturing is simplified, but real-time flow control during cardiac cycle is not achieved
Solution Approach 1:
The patent replaces complex mechanical valve mechanisms with a more manufacturable resistance modulation system that achieves flow control through material properties or simplified actuation mechanisms, balancing ease of manufacture with real-time operational capability.
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 effectively regulates blood flow, reducing the need for frequent surgeries and preventing damage to the lungs and systemic circulation by synchronizing with the cardiac cycle to manage excessive flow, thus improving patient outcomes.
Implementation Method 1
a pump configured to modulate a pressure of a second fluid within the interior space, where the deformable inner wall expands toward the central axis when the pressure of the second fluid is increased to apply a constrictive force to a section of the tubing
Implementation Method 2
a deformable inner wall which defines a central opening that extends along a central axis of the flow control cuff... the deformable inner wall expands toward the central axis when the pressure of the second fluid is increased
Data Source
AI summary
A passive implantable medical device for controlling a flow of fluid through a tube within a patient includes a first component and a second component movably coupled to one another and defining a central passage configured for receiving a portion of the tube therethrough. The passive implantable medical device is configured for moving between a first configuration and a second configuration to constrict a portion of the tube. An active implantable medical device for controlling a flow of a first fluid through a tubing includes a flow control cuff comprising a stiff outer wall and a deformable inner wall which defines a central opening sized such that the tubing can extend therethrough. A pump is configured to modulate a pressure of the second fluid within the interior space to apply a constrictive force to a section of the tubing.