Needle-injection Catheter with Penetration Limiting Elements
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Solution Overview
Problem
Current medical delivery systems for intracardiac delivery of cells, drugs, and other therapeutic agents face challenges in accessing the heart via a radial artery approach, particularly in providing a guide catheter that can navigate small diameters and bends without damaging the vasculature, and in preventing the loss of injected material due to heart contraction.
Innovation Solution
The development of systems and methods for intracardiac, trans-endocardial infusion using guide catheters with pre-shaped or steerable distal ends, and needle-injection catheters with penetration limiting elements that self-deploy to prevent excessive penetration into the myocardium, allowing for the delivery of large cellular aggregations and high viscosity therapeutic agents while minimizing the risk of embolism and material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a small diameter guide catheter is used for radial artery access, then the risk of vascular damage is reduced and patient recovery is improved, but the ability to navigate bends with angles greater than 70 degrees is compromised
Solution Approach 1:
The guide catheter is divided into multiple segments with different stiffness characteristics. The proximal portion has higher stiffness for pushability, while the distal portion has lower stiffness for flexibility and navigation. This segmentation allows the catheter to navigate sharp bends while maintaining structural integrity and minimizing vascular damage risk.
Solution Approach 2:
The guide catheter incorporates a shape memory alloy wire that can dynamically change its shape in response to temperature changes or mechanical activation. This allows the catheter to transition from a straight configuration during insertion to a pre-shaped configuration for navigating specific anatomical pathways, improving both navigation capability and safety.
2Strength
If a stiff distal region is used in the delivery catheter, then the ability to penetrate the endocardial wall is improved, but the risk of perforating the heart is increased
Solution Approach 1:
The delivery catheter is designed with non-uniform stiffness distribution along its length. The distal region has increased stiffness for effective endocardial penetration, while the proximal region maintains flexibility for safe navigation through the vasculature. This local quality differentiation allows the catheter to perform its penetration function while minimizing the risk of heart perforation through controlled flexibility in other regions.
Solution Approach 2:
The guide catheter is pre-shaped with a specific curvature that positions the delivery catheter's distal tip at the optimal location on the endocardial wall before penetration occurs. This preliminary positioning action ensures that the stiff distal region engages the tissue at the correct angle and location, reducing the risk of inadvertent perforation while maintaining effective penetration capability.
3Quantity of substance
If a large bore needle is used for delivering cellular aggregates, then the delivery capacity is improved, but the profile of the delivery system is increased
Solution Approach 1:
The delivery catheter with its large bore needle is nested within the guide catheter. The guide catheter provides a protective sheath that conceals the larger profile of the delivery catheter during navigation through the vasculature. Once positioned at the target site, the delivery catheter can be deployed to deliver cellular aggregates through its large bore needle, thus achieving high delivery capacity while maintaining a small overall profile during the procedure.
Data Source
AI summary
A needle-injection catheter includes a catheter body having a distal end, a proximal end, a stiff proximal portion, a flexible distal portion, and a delivery lumen extending therethrough. In a first embodiment, a straight injection needle extends coaxially from a distal tip of the flexible portion of the catheter body, and a plurality of penetration limiting elements positioned circumferentially about a base of the straight injection needle and configured to fold radially inwardly against a shaft of the needle when constrained in a tubular lumen and to extend radially outwardly when unconstrained. In a second embodiment, a helical needle extends from the distal tip of the flexible portion of the catheter body. The helical needle has at least one helical delivery lumen connected to receive an injectable substance from the delivery lumen of the catheter body.