Tri-lumen Sheath with Wire Segments for Cardiac Lead Extraction
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Solution Overview
Problem
Existing devices for removing implanted cardiac leads from biological tissue face challenges such as encapsulation by fibrotic tissue, which makes extraction difficult and often requires complex procedures or leaves leads in the patient, risking complications like thrombosis, arrhythmia, and septicemia.
Innovation Solution
A tri-lumen sheath device with a bending zone and wire segments that alternately compress and expand, allowing the distal end to extend or retract to cut through encapsulating tissue, facilitating the removal of implanted leads with minimal vessel disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional lead removal methods are used, then the lead can be removed from the pacemaker, but the lead becomes difficult to extract due to encapsulation by fibrotic tissue, requiring complex procedures or open heart surgery
Solution Approach 1:
The device employs a nested structure where an inner catheter with cutting elements is contained within an outer sheath. The inner catheter can be advanced through the outer sheath to the encapsulated lead, allowing the cutting elements to engage and sever the fibrotic tissue encapsulation. This nested configuration enables complex extraction capability while maintaining a relatively simple overall device structure that can be delivered through standard vascular access.
Solution Approach 2:
The device performs preliminary action by first delivering the cutting elements to the site of encapsulation before attempting lead extraction. The inner catheter with cutting elements is advanced through the outer sheath to the encapsulated lead, and the cutting elements are deployed to sever the fibrotic tissue before the lead is pulled back through the sheath. This preliminary cutting action facilitates subsequent lead removal without requiring complex open surgery.
2Productivity
If the lead is forcibly removed from encapsulated tissue, then extraction may be achieved, but severe damage or destruction of the vein occurs
Solution Approach 1:
The device extracts only the fibrotic tissue encapsulation from around the lead using cutting elements on the inner catheter. By selectively removing the encapsulating tissue while leaving the vein intact, the lead can be withdrawn through the outer sheath without forcing it through damaged vessel walls. This selective extraction approach enables efficient lead removal while minimizing harm to the blood vessel.
Solution Approach 2:
The outer sheath serves as an intermediary structure that provides a controlled pathway for lead removal. The cutting elements on the inner catheter act as intermediaries to sever the fibrotic encapsulation. This intermediary approach allows the lead to be extracted through a controlled mechanism rather than direct forceful removal, preventing severe vessel damage while maintaining extraction efficiency.
3Device complexity
If multiple leads are left in the patient, then removal complexity is avoided, but complications such as thrombosis, arrhythmia, and septicemia risk increase
Solution Approach 1:
The device replaces the need for complex mechanical open-heart surgical extraction with a less invasive mechanical system. The outer sheath is delivered through vascular access, and the inner catheter with cutting elements mechanically severs the fibrotic encapsulation. This mechanical substitution enables complete lead removal through a simpler procedure, eliminating the need to leave leads in place and thereby reducing complications such as thrombosis, arrhythmia, and septicemia risks.
4Ease of operation
If open heart surgery is performed for lead removal, then complete extraction is achieved, but significant costs, risks, and complications are incurred
Solution Approach 1:
The device employs a disposable single-use configuration where the outer sheath and inner catheter are delivered, used to extract the encapsulated lead, and then discarded. This disposable approach eliminates the need for expensive, complex open-heart surgery while achieving complete lead extraction. The cost and risk associated with surgical procedures are significantly reduced by using a less invasive, single-use device system.
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
Enables effective extraction of encapsulated cardiac leads with reduced risk of vessel damage and complications, allowing for safe removal without the need for open heart surgery.
Implementation Method 1
The sheath wall surface having the first and second lumens disposed therein is alternately compressible and expandable responsive to a bend along the bending zone
Data Source
AI summary
A device for extracting an implanted elongated structure from biological tissue comprises a sheath having a plurality of lumens therein opening to the sheath distal end. First and second lumens are disposed along a wall of the sheath, and a third lumen is dimensioned to receive the elongated structure. The sheath wall having the first and second lumens disposed therein is alternately compressible and expandable responsive to a bend along a bending zone of the sheath. A first wire segment is positioned in the first lumen, and a second wire segment is positioned in the second lumen, wherein the respective proximal ends of the segments are affixed proximal to the bending zone. The respective wire segments extend distally in the respective first or second lumen a first distance beyond the distal end of the sheath when the bend compresses the wall surface generally adjacent the first and second lumens, and extend distally a second distance, less than the first distance, when the bend expands the wall surface.