Variable curve catheter

Inventors

Karmarkar, ParagLederman, Robert J.

Assignees

Health and Human Services NIHUS Department of Health and Human Services

Publication Number

US-7918819-B2

Publication Date

2011-04-05

Expiration Date

2023-11-14

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Abstract

Disclosed is a deflectable tip guiding device, such as a catheter, that enables a physician, or other health care personnel, to vary the radius of curvature of the tip of the device. In one embodiment, a guiding device includes an elongate body and a deflectable distal tip. An elongate stiffener tube is coupled to the body for longitudinal movement relative thereto and has a distal end spaced a variable distance from the distal end of the tip, thereby serving as a fulcrum for the tip. Longitudinal movement of the stiffener tube relative to the body varies the distance between the distal ends of the tip and tube, which in turn causes a corresponding increase or decrease in the radius of curvature of the tip.

Core Innovation

The invention relates to a deflectable tip guiding device, such as a catheter, that allows a user to vary the radius of curvature of the device's tip while positioned in or being steered through a patient's body. In one embodiment, the guiding device includes an elongate body and a deflectable distal tip, with a curvature-adjustment mechanism that provides a variable fulcrum to change the tip's bending radius.

The problem addressed arises from conventional deflectable catheters that have fixed-fulcrum tips with fixed radii of curvature. These fixed radii limit the deflectable segment length and consequently restrict navigation capabilities through tortuous pathways or access to certain anatomical walls, such as myocardial walls from a transaortic approach. Thus, there is a need for guiding devices that provide increased flexibility and variable curvature for enhanced navigation and access.

The invention provides a guiding device whose deflectable tip fulcrum can be axially displaced to vary the radius of curvature, allowing variation of the deflectable segment’s length or reach. This variable fulcrum enables access to or navigation along more complex trajectories, exemplified by applications like myocardial injection guiding catheters or endolumen-traversal systems. The curvature-adjustment mechanism typically involves an elongate stiffener tube slidable longitudinally relative to the catheter body, with the distal end of the stiffener tube serving as a moveable fulcrum for the tip, thereby varying its radius of curvature.

Claims Coverage

The independent claims introduce three main inventive features related to the catheter's structure and functionality.

Variable radius of curvature via curvature-adjustment mechanism

A catheter comprising an elongate body and a distal section deflectable by a pull wire, with a longitudinally extending inner lumen adapted for delivering agents into a subject. It includes a curvature-adjustment mechanism that provides a variable fulcrum for the distal section, enabling adjustment of the radius of curvature of the tip.

Slidable elongate stiffener tube acting as variable fulcrum

The curvature-adjustment mechanism comprises an elongate stiffener tube slidable longitudinally relative to the catheter body. The stiffener tube's distal end is spaced at a variable distance from the distal end of the distal section, thereby serving as a movable fulcrum. Longitudinal movement of this tube varies the radius of curvature of the distal section.

Catheter distal section with slotted tube for controlled deflection

The catheter’s distal section includes a slotted tube with longitudinally spaced slots on one side to reduce resistance to bending. A pull wire is operatively connected to the distal end of the slotted tube on the slotted side and extends proximally to allow user-controlled deflection. The stiffener tube can be concentrically disposed either inside or outside the slotted tube or the catheter body, forming part of the curvature-adjustment mechanism.

Together, these inventive features provide a catheter with a deflectable tip whose radius of curvature can be varied in vivo by longitudinal movement of a stiffener tube or sleeve acting as a variable fulcrum, supported by a slotted tube distal section controlled via a pull wire to enable versatile and adjustable navigation and therapeutic delivery capabilities.

Stated Advantages

Enables variation of the radius of curvature and length of the deflectable distal section to access more complex anatomical trajectories and reach areas not accessible by fixed-fulcrum catheters.

Permits better direct access to all endomyocardial walls from a transaortic approach and improves navigation through tortuous passages.

Compatible with various imaging methods including MRI, and can incorporate an imaging antenna for active tracking.

Provides multiple degrees of freedom including axial displacement, axial rotation, tip deflection, and variable length of deflecting tip, enhancing maneuverability.

Documented Applications

Use as a myocardial injection guiding catheter to access all endomyocardial walls from a transaortic approach.

Employment in endolumen-traversal systems or neolumen-creation devices for navigating complex geometric pathways.

Delivery of diagnostic, prophylactic, or therapeutic agents including pharmaceuticals, biologicals, chemicals, mechanical devices, and radiant energy into various anatomical structures such as heart, arteries, veins, lymphatics, oropharynx, bronchial tree, genitourinary system, gastrointestinal lumens, central nervous system, and potential spaces.

Delivery, manipulation, and actuation of mechanical agents like thermometers, sensors, cameras, probes, needles, electrocautery snares, biopsy forceps, and suction tubes proximal to target anatomical structures.

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