Interventional Blood Pump With Radially Expandable Catheter
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Solution Overview
Problem
Existing interventional blood pumps face issues with instability during high-speed rotation, uncertainty in impeller unfolding, significant pressure loss, and complications due to long flexible shafts, which affect pumping efficiency and vascular integrity.
Innovation Solution
The design incorporates a rigid impeller within a rigid impeller outer cylinder, a radially expandable catheter, and a shortened flexible shaft with a driving unit positioned inside the body, along with a mesh inlet bracket and outlet brackets to enhance stability and reduce vascular damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a soft shaft is used to drive the impeller at high speed, then the flexibility and ease of insertion are improved, but the stability during high-speed rotation deteriorates
Solution Approach 1:
The shaft is divided into two distinct segments: a flexible shaft portion for insertion and a rigid shaft portion for stable rotation. The flexible shaft (comprising flexible outer shaft and inner shaft) enables easy insertion through blood vessels, while the rigid shaft (with rigid outer shaft and inner shaft) provides stability during high-speed impeller rotation. This segmentation resolves the contradiction by assigning different mechanical properties to different functional zones of the shaft system.
Solution Approach 2:
The shaft system transitions from a purely flexible configuration to a hybrid flexible-rigid structure. The flexible shaft portion maintains dynamic adaptability for navigation through curved vessels, while the rigid shaft portion provides static stability for high-speed rotation. This dynamic design allows the system to exhibit appropriate mechanical characteristics for each operational phase.
2Ease of operation
If the impeller and impeller outer cylinder are folded for delivery, then the ease of insertion is improved, but the reliability of full unfolding at the operating position deteriorates
Solution Approach 1:
The impeller and impeller outer cylinder are pre-configured in a folded state within the delivery catheter for easy insertion. Once positioned at the target site, they are deployed to their functional configuration. This preliminary folding action enables minimally invasive delivery while ensuring reliable deployment at the operating position.
Solution Approach 2:
The impeller is nested within the impeller outer cylinder, which itself is nested within the delivery catheter. This nested configuration allows the components to be compressed to a small diameter for delivery through narrow vessels, while enabling full expansion at the destination for optimal pumping function.
3Ease of operation
If a long flexible shaft is used to connect the impeller to the driving unit outside the body, then the ease of operation is improved, but the harmful factors to blood vessels (vascular complications) increase
Solution Approach 1:
The driving unit is extracted from the external position and relocated to the proximal end of the delivery catheter, positioned within or adjacent to the body. This extraction eliminates the need for a long flexible shaft extending outside the body, thereby reducing vascular complications while maintaining operational ease through the catheter-based delivery system.
Solution Approach 2:
The delivery catheter serves as an intermediary structure that houses both the shortened flexible shaft and the driving unit. This intermediary configuration allows the driving unit to be positioned within the body without requiring a long external shaft, thus reducing vascular trauma while maintaining the ability to drive the impeller effectively.
4Object-affected harmful factors
If the catheter is made slender to reduce vascular damage, then the harmful factors to blood vessels are reduced, but the pressure loss increases and pumping efficiency deteriorates
Solution Approach 1:
The catheter is designed with dynamic expandability, transitioning from a compressed state during delivery to an expanded state at the operating position. In the compressed state, the catheter has a small outer diameter to minimize vascular damage during insertion. At the destination, it expands to provide a larger internal diameter for reduced pressure loss and improved pumping efficiency.
Solution Approach 2:
The catheter structure utilizes radial expansion to change its dimensional characteristics. The catheter wall expands radially outward at the operating position, increasing the internal diameter and cross-sectional area for blood flow. This dimensional change allows the catheter to maintain a slender profile during delivery while providing adequate flow capacity during operation.
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 design ensures stable high-speed rotation, reduces vascular complications, improves pumping efficiency, and minimizes damage to blood vessels by maintaining a large blood flow area and effective heat dissipation.
Implementation Method 1
a radially expandable catheter arranged outside the flexible shaft and extending in at least one part of the length of the flexible shaft
Implementation Method 2
a rotatable rigid impeller configured to provide power for the flow of blood
Implementation Method 3
When the motor drives the impeller to rotate, the blood is delivered from the inlet of the blood pumping catheter to the outlet
Implementation Method 4
A proximal end of the impeller is connected to a distal end of the driving unit through a flexible shaft
Implementation Method 5
improves pumping efficiency, and minimizes damage to blood vessels by maintaining a large blood flow area and effective heat dissipation
Data Source
AI summary
Disclosed is an interventional blood pump, including a pump body and a driving unit. The pump body includes a blood inlet and blood outlets. The pump body includes: a rotatable rigid impeller configured to increase power for the flow of blood and accommodated in a rigid impeller outer cylinder, a proximal end of the impeller being connected to a distal end of the driving unit through a flexible shaft, wherein a distal end of the impeller outer cylinder communicates with the blood inlet, and a proximal end of the impeller outer cylinder includes an impeller outlet; and a radially expandable catheter arranged outside the flexible shaft, a distal end of the radially expandable catheter being hermetically connected to the impeller outer cylinder and covering the impeller outlet, and a proximal end of the radially expandable catheter being provided with the blood outlets.