Expandable Cryogenic Balloon for Wide Atrial Ablation
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Solution Overview
Problem
Current methods for ablating myocardial tissue, particularly in the left atrium, face challenges such as difficulty in maintaining device position due to moving tissue and flowing blood, and the creation of narrow, irregular lesions, especially in the pulmonary veins, which can lead to adverse effects like RF energy-related complications.
Innovation Solution
A cryogenic ablation system with a catheter having an expandable ablation element, such as a balloon, that conforms to the uneven cardiac tissue surface, allowing for large-area tissue ablation by freezing, which adheres to the tissue and reduces the need for precise alignment, thereby creating wide-area lesions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a catheter-based device is used to ablate myocardial tissue, then the procedure can be performed minimally invasively, but the device is difficult to maintain in a selected position and orientation due to moving tissue and flowing blood
Solution Approach 1:
The ablation catheter employs a flexible balloon element that can conform to the irregular tissue surface. The balloon's flexibility allows it to adapt to tissue movement while maintaining contact, solving the position stability issue without compromising the minimally invasive nature of the procedure.
Solution Approach 2:
The catheter system incorporates dynamic positioning capabilities where the balloon can be inflated or deflated to adjust its shape and contact area with the tissue. This dynamic adjustment allows the device to maintain reliable positioning despite tissue movement and blood flow during the procedure.
2Manufacturing precision
If a narrow ablation element is used to ablate tissue, then precise alignment is required, but it is very difficult to achieve such precision in moving tissue
Solution Approach 1:
The invention transitions from a narrow linear ablation element to a two-dimensional balloon surface that can be inflated to create a large contact area. This dimensional change eliminates the need for precise linear alignment while still achieving accurate ablation of the target tissue area through surface conformal contact.
Solution Approach 2:
The balloon element merges multiple potential contact points into a single expanded surface that simultaneously contacts multiple tissue locations. This combining approach ensures comprehensive tissue coverage without requiring precise positioning of individual ablation points, solving the alignment difficulty in moving tissue.
3Shape
If microwave or RF ablation is used to create uniform circular lesions, then the intended result is a substantially uniform circle of ablated tissue, but the actual lesions are relatively narrow and irregular
Solution Approach 1:
The flexible balloon element conformally contacts the irregular tissue surface, distributing the ablation energy uniformly across the entire contact area. This creates wide, uniform lesions that match the intended shape, overcoming the narrow and irregular lesion formation associated with traditional microwave or RF ablation methods.
Solution Approach 2:
The invention changes the ablation parameter from concentrated thermal energy (microwave/RF) to cryogenic freezing. This parameter change, combined with the expanded balloon surface area, produces wide uniform lesions with consistent dimensions, eliminating the variability and narrow width problems of traditional ablation methods.
4Area of stationary object
If an expandable balloon is used to increase ablation area, then large-area tissue contact is achieved, but the device complexity increases
Solution Approach 1:
The balloon element is nested within the catheter body in a compressed state for delivery, then expanded at the target site to achieve large ablation surface area. This nesting approach allows the device to transition from a compact deliverable form to a large functional form without requiring excessive structural complexity in the delivery catheter.
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 cryogenic ablation system effectively modifies electrophysiological properties by creating large, contiguous lesions in the left atrium, reducing the risk of adverse effects associated with RF ablation and improving the treatment of atrial fibrillation by ablating regions beyond the ostium, enhancing clinical efficacy and safety.
Implementation Method 1
A cryogenic ablation system with a catheter having an expandable ablation element, such as a balloon, that conforms to the uneven cardiac tissue surface, allowing for large-area tissue ablation by freezing
Data Source
AI summary
The present invention advantageously provides a method and system for cryogenically ablating large areas of tissue within the left atrium. In an exemplary embodiment a cryotherapy device includes a catheter body having a substantially fixed diameter, a proximal end and a distal end; a first lumen for permitting passage of a cooling fluid from the proximal end to the distal end; a second lumen permitting return of the cooling fluid from the distal end to the proximal end; and an ablation element expandable from a first diameter that is substantially the same as the diameter of the catheter body to a second diameter that is at least twice the diameter of the catheter body, the ablation element having a surface portion that conforms to the uneven surface topography of the cardiac tissue. The ablation element can include one or more balloon and/or a flexible element that is deformed by moving the distal end of the catheter toward the proximal end of the catheter. The surface of the balloon can further be shaped by regulation of pressure within the one or more balloons. In an exemplary method a tissue ablation device is provided and tissue in the antrum of the left atrium is ablated with the device. In an exemplary method, only tissue in the antrum is ablated, and the ablation is created by freezing tissue.