Ventricular Assist Pump Structure for Low-Hemolysis Blood Flow
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Solution Overview
Problem
Current ventricular assist devices face challenges in efficiently pumping blood while minimizing hemolysis and preventing structural damage from entering the device.
Innovation Solution
The ventricular assist device incorporates a frame with a smooth inner lining to reduce hemolysis, a pump-outlet tube with strategically designed blood-inlet openings to prevent structural damage, and a protective braid to block unwanted structures from entering the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the frame uses a standard configuration without smooth inner lining, then manufacturing is simpler, but hemolysis increases during blood pumping
Solution Approach 1:
The patent applies a smooth inner lining (thin film) to the frame's internal surface to reduce hemolysis. This lining creates a blood-friendly surface that minimizes mechanical damage to blood cells during pumping, directly addressing the harmful effect while adding minimal manufacturing complexity through coating or lining processes.
2Productivity
If the pump-outlet tube has large blood-inlet openings, then blood flow efficiency improves, but structural damage from heart structures entering the device increases
Solution Approach 1:
The patent implements different opening sizes at different locations of the pump-outlet tube. Larger openings are positioned to optimize blood flow efficiency, while smaller openings or restricted areas are strategically placed to prevent heart structures from entering the frame. This local variation in opening quality resolves the contradiction between flow efficiency and structural protection.
3Volume of moving object
If the frame struts are positioned closely together, then device size is reduced, but blood flow efficiency decreases
Solution Approach 1:
The patent optimizes the three-dimensional arrangement of frame struts to create adequate blood flow channels while maintaining a compact overall device size. By strategically positioning struts in different spatial dimensions and creating optimized cell geometries, the design allows sufficient blood flow pathways without increasing the device's external dimensions, thus resolving the contradiction between size and flow efficiency.
4Reliability
If the protective braid is positioned further from the frame, then it blocks more structures, but it increases the risk of the braid moving during crimping
Solution Approach 1:
The patent embeds the protective braid within the frame structure during the crimping process. The braid is positioned and secured within the frame's cellular structure, allowing it to extend far enough to block heart structures while being mechanically anchored to prevent movement during crimping. This nested arrangement provides both protective coverage and positional stability.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An apparatus, comprising: a ventricular assist device (20) comprising: a frame (34) comprising struts that define a plurality of cells, the frame (34) being configured such that, in a non-radially-constrained configuration of the frame (34), the frame (34) comprises a generally cylindrical central portion (38); a pump-outlet tube (24) that defines one or more blood outlet openings (109), a portion of the pump-outlet tube (24) being disposed outside the frame (34) and coupled to the generally cylindrical central portion (38) of the frame (34), such that the portion of the pump-outlet tube (24) conforms with a structure of struts of the frame; an inner lining (39) coupled to an inside of the generally cylindrical central portion (38) of the frame (34), such as to provide the generally cylindrical portion (38) of the frame (34) with a smooth inner surface; an impeller (50) disposed at least partially inside the generally cylindrical central portion (38) of the frame (34) and configured to pump blood through the tube (24) and out of the one of more blood outlet openings (109); and a protective braid (150) disposed over a distal portion (40) of the frame (34) and configured to block structures from the subject's left ventricle from entering into the frame (34), a proximal end of the protective braid (150) being embedded between the pump-outlet tube (24) and the inner lining (39), such that, during crimping of the frame (34), the protective braid (150) becomes crimped with the pump-outlet tube (24) and the inner lining (39), thereby preventing the protective braid (150) from moving with respect to pump-outlet tube (24) or the inner lining (39).