Patent Application
20090171272
a. Field of the Invention
The present invention relates to a deflectable sheath and assembly, including a deflectable sheath access device or introducer, wherein the deflection and movement of the sheath access device is controlled through the relative movement of a plurality of sheaths with respect to one another. Moreover, the present invention relates to catheter assemblies designed for increased flexibility.
b. Background Art
Many medical procedures require the introduction of specialized medical devices into and/or around the human heart. In particular, there are a number of medical procedures that require the introduction of specialized devices including, but not limited to, catheters, dilators, and needles to areas, such as into the atria or ventricles to access the inner surface of the heart, or into the pericardial sac surrounding the heart to access the epicardial or outer surface of the heart. Catheters and access sheaths or introducers have been used for medical procedures for a number of years. It is typically necessary for introducers and catheters to exhibit a degree of flexibility to be able to maneuver through the vasculature of a patient during the performance of cardiac procedures. In additional, various configurations of introducers are necessary for the treatment of different cardiac conditions.
Traditional catheters and access devices, such as introducers, access endocardial areas through a rigid elongated body that includes a curved portion for accessing areas of the heart and related vasculature for ablation. Conventional sheaths, introducers, and catheters are commonly configured with pull wires to control the movement and relative curvature of the devices. The movement of these deflectable devices is primarily controlled by at least one pull wire that is provided about or within the wall of the devices. The pull wires extend along the length of the sheath and are coupled and/or connected to a control mechanism, such as, for example, a knob that can be rotated, which results in the defection of the elongated body of the sheath, introducer or catheter.
For some applications, a steerable sheath (or other access device) comprise an elongated body that may become difficult to control as the elongated is extended and becomes longer. In particular, the pull wires that extend along the length of the sheath are commonly controlled by a mechanism that is provided within a handle at or about the proximal end of the sheath. In various procedures, such as in the treatment of atrial fibrillation or ventricular tachycardia, it is necessary to place this access sheath within the right or left atrium for insertion of a catheter. Accordingly, the movement of the sheath in combination with the catheter must be controlled to a high degree of precision due to the sensitivity of the procedures. One problem often encountered with prior access sheaths and access devices is that once the sheath or device becomes deflected, it may become difficult to apply torque to the sheath or access device without whipping the pull wires provided in or along the wall of the sheath.
In addition to the more rigid deflectable access sheaths and introducers, catheter assemblies provided within the access sheath for access to the target tissue are provided with a tip portion that is traditionally more rigid in order to be manipulated into place. During an intra-cardial procedure, such as those used to treat atrial fibrillation or ventricular tachycardia, there is always a risk for dissection of the tissue with the catheters and the tools being used to perform the procedure. In addition, with the increased use of robotic manipulation systems for the catheters, it can become necessary to provide distal tip sections that are safe to deploy as a user may no longer have direct feedback provided by sensations associated with touch. Currently, there are some catheters that employ a removable inner member to stiffen the catheter for easier insertion through the introducer. Such a stiffer inner member can be removed to soften the distal portion of the catheter. One challenge associated with these types of catheters is that the removable inner member may take up valuable room inside the catheter device and ultimately an extra component must be dealt with by the user and eventually disposed of.
Current access sheath devices and catheter assemblies attempt to maintain control and rigidity through the use of known control mechanisms, i.e., for example, pull wires. Each of these traditional devices may present challenges with being maneuvered and providing catheter tips that are rigid enough to be manipulated into place while at the same time being readily deflectable and soft enough to prevent damage to the sensitive tissue.
The present invention is directed to deflectable access sheaths or introducers, including a deflectable sheath access device. The present invention includes a deflectable sheath access device or introducer in which the deflection and movement of the sheath access device can be controlled via the relative movement of a plurality of sheaths to one another. In particular, the deflectable sheath access device of the present invention includes a primary sheath, a secondary sheath, and a controller that operably work together to control the positioning and movement of the access device.
Accordingly, embodiments of the present invention provide a deflectable sheath access device. The device includes a primary sheath having a proximal portion and a distal portion having a distal end. The primary sheath further includes a lumen that extends through the length of the primary sheath. The distal portion of the primary sheath further includes a fixed curve. The secondary sheath of the present invention is defined by a longitudinal axis and further includes a proximal end. The secondary sheath (which may also be referred to as a “secondary straight sheath”) is disposed about the proximal portion of the primary sheath. The device of the present invention further includes a controller that includes a control member coupled to the proximal end of the secondary sheath, and controls the relative axial movement of the secondary sheath along the longitudinal axis of the secondary sheath to control the movement of the secondary sheath relative to the primary sheath.
The present invention further provides a deflectable access assembly. The assembly may be used to performing a number of medical procedures. The assembly includes a deflectable sheath access device having a primary sheath, a secondary sheath, and a controller. The primary sheath includes a proximal portion and a distal portion having a distal end. The primary sheath further includes a lumen that extends through the length of the primary sheath. The distal portion of the primary sheath may further include a fixed curve. The secondary sheath of the present invention includes a longitudinal axis and a proximal end. The secondary sheath is disposed about the proximal portion of the primary sheath. The device of the present invention further includes a controller having a control member that is coupled to the proximal end of the secondary sheath and controls the relative axial movement of the secondary sheath along the longitudinal axis of the secondary sheath. This axial movement enables the secondary sheath to move relative to the active movement of the primary sheath. The assembly further includes a catheter comprising a catheter shaft having a distal end portion and a proximal portion, wherein an ablation electrode is coupled to the distal portion of the shaft, for insertion into the passageway defined by the deflectable sheath access device.
The present invention further provides various embodiment of catheter assemblies. In particular, the present invention provides embodiments of catheter assemblies that may be used in connection with the access device of the present invention. Moreover, the catheter assembly, as provided by the present invention, have increased flexibility for use in connection with an access device. The catheter shaft of the present invention includes a distal end portion and a proximal portion. The distal portion may have a durometer less than the proximal portion of the catheter shaft. Furthermore, the present invention may further provide a catheter shaft comprised of a material having a durometer less than traditional catheters, therein providing a flexible or floppy tipped catheter.
Accordingly, deflectable sheath access devices as provided by the present invention, as well as the related assemblies, may be provided to enhance and perform the method of ablating epicardial surface for the treatment of atrial fibrillation and ventricular tachycardia, while readily controlling the movement of the access sheath assembly.
The foregoing and other aspects, features, details, utilities, and advantages of embodiments of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.
In general, the present invention relates to a deflectable sheath access device or introducer for use in epicardial procedures, such as those used for the treatment of atrial fibrillation and ventricular tachycardia. Furthermore, the present invention relates to a catheter assembly for use with the deflectable sheath access device that includes a relatively flexible tip portion. The deflectable access device provides a primary sheath and a secondary sheath for controlling movement and relative positioning of the deflectable sheath access device, for example, to epicardial surfaces for performing ablation. For purposes of this description, similar features among the various embodiments described herein will be referred to by the same reference number. As will be appreciated, however, the structure of the various aspects may differ with respect to alternate embodiments.
The deflectable access device, or introducer, of the present invention is configured such that pull wires are not necessary to control the relative movement and positioning of the access device. Even with the absence of pull wires, the present invention enables a degree of curvature of the access device to be maintained and modified through the relative movement of access sheaths to one another.
As generally shown in the embodiment illustrated in
In accordance with an embodiment, as generally illustrated in
Access device 10 further includes a secondary sheath 22 that is defined by a longitudinal axis. Secondary sheath 22 further includes a proximal end 30. The secondary sheath is substantially straight (and, hence, is also referred to as a “secondary straight sheath” or a “straight sheath”) and the secondary sheath maintains its relative rigidity through the operation and movement of access device 10, as described below. The term “straight” is meant to include substantially or relatively straight in relation to any curved portion or part of primary sheath 20. Secondary sheath 22 may be disposed about proximal portion 26 of primary sheath 20. Accordingly, as illustrated in
Device 10 may further include locking mechanism 36 to secure the relative position through the use of friction of primary sheath 20 and secondary sheath 22. Locking mechanism 36 may be provided at the proximal end 40 of device 10, or, as illustrated in connection with
As can be seen in
Variations in size and shape of primary sheath 20 may be used and are intended to encompass all applicable uses. It is recognized that based on the application and/or use of device 10, the length of primary sheath 20 may vary slightly. Primary sheath 20, in accordance with the present invention, is generally configured to be shorter than the length of traditional catheter assemblies, so that the distal end of the catheter including the electrode may be disposed out of distal tip portion 28, as illustrated in
As generally illustrated in
As previously described and shown in
As further shown in
In addition to various embodiments of access device 10 as previously described, the present invention further provide access assembly 12 as shown in
In accordance with embodiments of the present invention and in connection with the use of the access device 10, it may be desirable to have a catheter shaft 16 and in particular a distal end portion 46 of catheter shaft 16 that has increased flexibility (i.e. floppy) compared to traditional catheter assemblies. In particular, it may be desirable to use softer, more desirable material while at the same time meeting industry standards regarding the rigidity and tensile strength of catheter shafts. Various modifications may be made to provide flexible or floppy tip catheters that perform in accordance with softer materials, while at the same time meeting the tensile strength standards of the industry, as well as any other applicable standards.
Catheter assembly 14, in accordance with an embodiment of the present invention, may provide a catheter shaft 16 that is comprised of a material that has a soft durometer, i.e., for example 25-40 durometer, therein exhibiting increased flexibility in the catheter shaft. Overall, the distal end portion 46 of catheter shaft 16 may have a stiffness range of approximately 0.005 lbs to 0.100 lbs when measured using a 1 inch long section supported at one end and the relative displacement of distal tip section 46 to the longitudinal axis of catheter shaft 16 may be approximately 0.500 inches.
Moreover, as generally illustrated in
In an embodiment, as generally shown in
As further illustrated in
Another embodiment of catheter assembly 14, as generally shown in
Although not illustrated, each of the provided embodiment of catheter shaft 16 may further include a reinforced section that may, for example, be provided within distal section 46 of catheter 16. Such a reinforced section (or segment) may employ or include a glass fiber braid that has extremely high tensile strength and increase flexibility. The glass fiber braid may be selected form various fibers, including Vectran®. Moreover, catheter assemblies having tip electrodes may use an auxiliary wire fastened to the electrode tip for safety. In order to maintain tensile strength in the flexible (or floppy) catheters while at the same time keeping the wire flexible, a braided safety wire can be used. A braided safety wire may be braided from 0.0010-0.0015″ metal wire to make a high flexible high tensile strength braided assembly.
Embodiments of flexible catheters, including those with catheter shafts as generally illustrated and discussed above, may be readily incorporated with an access device 10 for performing ablative procedures. Other types of energy sources may also be used in connection with access sheath device 10 of the present invention, such as ultrasound (e.g. HIFU), laser, or other energy used for performing ablative procedures. Additional electrode tips may be used and configured, such as a closed loop cooled tip, for incorporation with the shorted catheter assembly for insertion within access sheath device 10.
An assembly or kit for use in treating various conditions, may include deflectable access sheath device 10 and catheter assembly 14, as such described in accordance with the multiple embodiments of the present invention.
Although a number of embodiments of this invention have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.
