Expandable Sleeve Inflow Cannula for VAD Thrombus Prevention
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Solution Overview
Problem
Inflow cannulas for ventricular assist devices (VADs) often result in areas of low blood flow or stasis around the cannula, leading to potential thrombus formation within the heart.
Innovation Solution
An expandable sleeve is integrated with the inflow cannula, deployable from a stored configuration to a radial configuration that engages and conforms to the endocardial surface of the heart, occupying areas of low blood flow and preventing thrombi detachment into the bloodstream, while promoting tissue reendothelialization and maintaining an open flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inflow cannula is implanted within the left ventricle to supply blood from the ventricle to the pump, then blood circulation is improved, but areas of low blood flow or stasis are created around the cannula which can lead to thrombus formation
Solution Approach 1:
The patent applies a flexible expandable sleeve made of biocompatible material that conforms to the endocardial surface. This flexible shell structure creates a smooth transition between the cannula and heart tissue, eliminating sharp edges and protrusions that cause flow disruption and thrombus formation, while maintaining improved blood circulation through the cannula.
Solution Approach 2:
The patent transitions from a simple tubular cannula structure to a three-dimensional solution by adding an expandable sleeve that extends radially outward from the cannula surface. This dimensional addition creates a larger smooth surface area that redirects blood flow and eliminates stagnant zones around the cannula, preventing thrombus formation while preserving circulation benefits.
2Reliability
If the cannula protrudes into the heart ventricle to ensure adequate blood intake, then pump function is maintained, but tissue overgrowth and healing complications occur
Solution Approach 1:
The expandable sleeve acts as a flexible barrier that promotes proper tissue healing by providing a smooth interface between the cannula and endocardial surface. This prevents excessive tissue overgrowth and fibrosis around the cannula, ensuring reliable pump function while reducing healing complications.
Solution Approach 2:
The expandable sleeve serves as an intermediary structure between the cannula and the heart tissue. It mediates the interaction by providing a biocompatible surface that reduces direct tissue-cannula contact, thereby preventing harmful tissue overgrowth while maintaining adequate blood intake for pump function.
3Stability of the object's composition
If the cannula is secured to the heart to prevent displacement, then device stability is improved, but areas of low blood flow are created leading to thrombus formation
Solution Approach 1:
The expandable sleeve provides device stability through friction and tissue ingrowth while simultaneously eliminating flow disruption zones. The smooth flexible surface prevents thrombus formation even as the sleeve anchors the cannula securely to the heart, resolving the contradiction between stability and thrombus prevention.
Data Source
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AI summary
Disclosed herein is an inflow cannula for an implantable blood pump assembly. The inflow cannula includes a tubular body that extends from a proximal end to a distal end. The tubular body includes a proximal portion adapted for connection to a pump housing, and a distal portion adapted for positioning within an opening formed in a heart. The inflow cannula further includes an expandable sleeve coupled to an exterior surface of the distal portion. The sleeve has a first portion coupled to the distal portion of the tubular body, and a second portion extending from the distal end of the tubular body. The second portion is deployable from a first, stored configuration to a second, deployed configuration in which the second portion expands radially to engage and conform to an endocardial surface of the heart.