Locking Guide Catheter Hubs for Preventing Sheath Retraction
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Solution Overview
Problem
Conventional systems for delivering implantable medical devices (IMDs) suffer from issues such as the sheath slipping during navigation, leading to potential exposure of the helix and inadequate sealing, which can compromise the secure implantation of the device.
Innovation Solution
A delivery device with a locking hub system featuring a compressible clamping gasket and actuator mechanism that secures the outer shaft to the inner shaft in a locked condition, providing a liquid-tight seal and preventing unintended sheath retraction, while allowing sliding motion in the unlocked condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hemostasis seal is used in the delivery device, then the device can be navigated through vasculature, but the seal may not grip the catheter tightly enough, causing the sheath to slip backwards and expose the helix
Solution Approach 1:
The sealing system is divided into two distinct components: a hemostasis seal for fluid sealing and a locking seal for mechanical gripping. This segmentation allows each component to be optimized for its specific function without compromise - the locking seal provides tight gripping capability while the hemostasis seal maintains fluid sealing, preventing sheath slippage during catheter manipulation
Solution Approach 2:
The locking seal acts as an intermediary component between the outer shaft and the inner shaft/catheter assembly. This intermediate locking mechanism transfers and secures the mechanical connection, ensuring that forces during manipulation are properly distributed and the sheath remains firmly positioned without exposing the helix
2Adaptability or versatility
If the sheath is made retractable for device deployment, then the IMD can be delivered to target location, but unintended retraction may occur during navigation, exposing the helix
Solution Approach 1:
The locking seal engages in advance during the navigation phase to firmly secure the sheath to the catheter assembly. This preliminary locking action prevents any unintended retraction before the actual deployment is intended. The operator can then deliberately control sheath retraction only after proper positioning, ensuring the helix remains protected throughout navigation
3Ease of operation
If the delivery device allows sliding motion for sheath retraction, then device deployment is enabled, but the seal may not maintain fixed position, compromising implantation precision
Solution Approach 1:
The delivery device employs a dynamic locking mechanism where the locking seal can transition between engaged and disengaged states. During navigation, the locking seal is engaged to maintain fixed positioning and precision. During deployment, the operator can disengage the lock to allow controlled sheath retraction. This dynamic capability provides both operational flexibility and precision when needed
Solution Approach 2:
The dual-seal system provides mechanical feedback to the operator about the sheath-catheter connection status. The locking seal's engagement state gives tactile and visual feedback, allowing the operator to confirm proper locking before navigation and controlled disengagement only when ready for deployment, maintaining precision throughout the procedure
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 locking hub system ensures stable and secure implantation of IMDs by maintaining a fixed longitudinal position during navigation, preventing unintended sheath retraction and ensuring a reliable seal, thereby enhancing the implantation process.
Implementation Method 1
a compressible clamping gasket that prevents relative longitudinal motion between the outer shaft and the inner shaft
Implementation Method 2
a hemostasis gasket that provides a liquid-tight seal against the inner shaft
Data Source
AI summary
A delivery device for an implantable medical device may include an inner shaft configured to retain the implantable medical device at its distal end, an outer shaft slidably disposed about the inner shaft, and a locking hub affixed to the outer shaft. The locking hub may include a housing, a piston element in the housing, an actuator operatively coupled to the piston element, and a clamping gasket made of a compressible material and disposed in the housing. The actuator may be movable relative to the housing between unlocked and locked conditions. The clamping gasket may have a lumen defining a first diameter with the actuator in the unlocked condition and a second diameter with the actuator in the locked condition, the second diameter being less than the first diameter. The outer shaft and the locking hub may be fixed to the inner shaft with the actuator in the locked condition.