Microcatheter Balloon Anchoring for Crossing Chronic Total Occlusions
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Solution Overview
Problem
Conventional guidewires face challenges in crossing chronic total occlusions (CTOs) due to buckling at the proximal cap and difficulty in navigating through long, tortuous lesions while minimizing force on the vessel wall, leading to low procedural success rates in endovascular interventions.
Innovation Solution
A microcatheter system with a distal crosser unit and actuator that uses a proximal balloon to longitudinally expand, anchoring the guidewire and microcatheter to the tissue, allowing sequential advancement across the occlusion, minimizing insertion force and preventing buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional guidewires are used to cross CTOs, then the procedure can be performed with simple equipment, but the guidewire buckles at the proximal cap and procedural success rate is low
Solution Approach 1:
The guidewire system is divided into multiple functional segments: a microcatheter for delivery and support, a guidewire with specific tip geometry for penetrating the proximal cap, and a distal anchor member for stabilization. This segmentation allows each component to be optimized for its specific function while working together to overcome the CTO lesion.
Solution Approach 2:
The microcatheter is advanced and positioned proximal to the CTO lesion before the guidewire is deployed. The guidewire is then advanced through the microcatheter to the proximal cap, and the distal anchor member is deployed into the distal true lumen before attempting to cross the occlusion. These preliminary positioning actions ensure proper support and alignment before the critical crossing maneuver.
2Productivity
If force is applied to push the guidewire through the proximal cap, then the guidewire can cross the occlusion, but the guidewire buckles and vessel wall damage occurs
Solution Approach 1:
The microcatheter serves as an intermediary device that provides continuous support to the guidewire from the proximal vessel through the CTO lesion. This support mechanism distributes the pushing force along the guidewire length rather than concentrating it at the tip, preventing buckling and reducing the risk of vessel wall damage while maintaining crossing efficiency.
Solution Approach 2:
The guidewire tip is designed with specific geometric parameters (angled tip, controlled stiffness) that allow it to penetrate the fibrocalcific proximal cap with minimal force. The distal anchor member is designed to engage the distal true lumen and provide mechanical advantage, changing the force dynamics from direct pushing to leveraged advancement, thereby reducing vessel wall stress.
3Stability of the object's composition
If the guidewire is made stiffer to prevent buckling, then buckling resistance improves, but the guidewire cannot navigate tortuous CTO lesions
Solution Approach 1:
The guidewire exhibits different mechanical properties at different locations: the proximal portion within the microcatheter is supported and stabilized, the tip portion has optimized stiffness and geometry for penetrating the proximal cap, and the distal portion is flexible enough to navigate tortuous anatomy. This local differentiation of mechanical properties allows the guidewire to simultaneously achieve stability where needed and adaptability where required.
Solution Approach 2:
The guidewire system transitions from a static, uniformly flexible conventional design to a dynamic system where the microcatheter provides active support that can be adjusted during advancement. The distal anchor member can be deployed at different positions depending on the lesion morphology, allowing the system to adapt its mechanical characteristics to the specific anatomical challenges encountered.
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 system effectively navigates through CTOs by maintaining guidewire stability, improving the likelihood of successful crossing and reducing vessel wall damage, enhancing procedural success rates.
Implementation Method 1
a proximal balloon attached to both the microcatheter and the guidewire, wherein the proximal balloon is configured to longitudinally expand
Implementation Method 2
a distal anchor member present on the guidewire
Data Source
AI summary
A microcatheter system for crossing total occlusions including a distal crosser unit and an actuator is disclosed. The distal crosser unit comprises: a microcatheter having a guidewire lumen; a guidewire present in the guidewire lumen and extending beyond the distal end of the microcatheter; a proximal balloon attached to both the microcatheter and the guidewire, wherein the proximal balloon is configured to longitudinally expand; and a distal anchor member present on the guidewire. And the actuator is configured to sequentially inflate and deflate the proximal balloon such that the distal crosser unit progressively moves across a chronic total occlusion.