Patent Application
20230201562
The present disclosure relates generally to implantable medical devices, and more specifically, relates to guidewire guides for use in implantable medical devices.
Heart disease is a major health problem that has a high mortality rate. Physicians increasingly use mechanical circulatory support systems for treating heart failure. The treatment of acute heart failure requires a device that can provide support to the patient quickly. Physicians desire treatment options that can be deployed quickly and minimally-invasively.
A Percutaneous Heart Pump (PHP) system is one example of a ventricular assist device that may be used during high-risk percutaneous coronary interventions (PCI) performed electively or urgently in hemodynamically stable patients with severe coronary artery disease, when a heart team, including a cardiac surgeon, has determined high-risk PCI is the appropriate therapeutic option. Use of the PHP system in these patients may prevent hemodynamic instability, which can result from repeat episodes of reversible myocardial ischemia that occur during planned temporary coronary occlusions and may reduce pre-and post-procedural adverse events. PHP systems may also be used to treat cardiogenic shock in certain circumstances.
In at least some embodiments, the PHP system includes a distal septum to prevent blood from entering a fluid lumen of a catheter of the PHP system. In such embodiments, a guidewire guide (GWG) may extend through a distal septum for a period of time (e.g., while the PHP system is being stored), which may impact the sealing capabilities of the distal septum. Accordingly, it would be desirable to provide a GWG that facilitates reducing impacts on the sealing capabilities of the distal septum.
In one aspect of the present disclosure a septum is disclosed for use in a catheter pump. The septum includes a first elastomeric septa disc. The first septa disc is punctured to form an aperture in the first elastomeric disc. The aperture is passable by a guidewire.
In another aspect of the present disclosure, a catheter assembly is disclosed for use in a percutaneous heart pump. The catheter assembly includes a pump assembly that includes an impeller, an impeller tip positioned distal of the impeller, and a distal septum positioned between the impeller and the impeller tip. The catheter assembly also includes a flexible atraumatic tip (FAT) positioned distal of the pump assembly. The catheter assembly also includes a guidewire guide (GWG) coupled between the pump assembly and the FAT where a proximal end of the GWG is positioned distal of the distal septum.
In yet another aspect of the present disclosure, a method of assembling a catheter assembly for use in a percutaneous heart pump (PHP) is disclosed. The method includes coupling a pump assembly to the catheter assembly where assembling the pump assembly includes positioning an impeller in the pump assembly. Assembling the pump assembly also includes positioning an impeller tip in the pump assembly at a position distal of the impeller. Assembling the pump assembly also includes positioning a distal septum between the impeller and the impeller tip. Assembling the catheter assembly also includes positioning a flexible atraumatic tip (FAT) distal of the pump assembly. Assembling the catheter assembly also includes coupling a guidewire guide (GWG) between the pump assembly and the FAT, where the proximal end of the GWG is positioned distal of the distal septum.
The foregoing and other aspects, features, details, utilities, and advantages of the present disclosure will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
The disclosure provides systems and methods for guidewire guides (GWGs) for use in a medical system. In various embodiments disclosed herein, a GWG may be configured to receive a guidewire therethrough. A clinician may maneuver the guidewire to the heart through the patient's vasculature. The clinician may then advance a distal portion of a catheter assembly over the guidewire, using the GWG, to position the distal portion (e.g., including an impeller) in a chamber of the heart. In some embodiments, the GWG may include a central lumen formed along at least a portion of the length of the catheter assembly. The clinician may then withdraw the guidewire from the catheter assembly.
Additional embodiments of this disclosure are directed to apparatuses for improving resistance of fluid flow in the apparatus. For example, in the operative device, a septum may be included at a distal portion of the apparatus through which the GWG is threaded. In particular, various embodiments disclosed herein generally relate to various configurations for a septum at a distal end of a GWG in a catheter assembly. Accordingly, the septum may be comprised of one or more separate septa discs. Each septa disc may be punctured during catheter assembly. Accordingly, the septa discs may include openings or apertures of varying shape and size through which a guidewire or guidewire guide may pass through.
In the exemplary embodiment, the septa discs include offset openings respective of one another. When housed within the catheter assembly, the septa discs are in alignment and, accordingly, the openings in each respective disc are disaligned from each other respective septa disc.
Embodiments of pump assemblies, such as pump assembly 100 (shown in
GWG 102 may be made of flexible alloys, such as nitinol, a grade of stainless steel, and/or advanced polymers such as polyamide, HDPE, LLDPE, FEP, PET, Pebax, etc. Any of these materials may include a pattern cut into them to improve flexibility and prevent kinking. GWG 102 may also include a reinforced sheath (e.g., a thin braid structure) that also improves flexibility and prevents kinking (particularly in embodiments where GWG 102 rotates during operation of pump assembly 100).
As shown in
As cannula 110 is sheathed, FAT 112 moves distally, for example, by approximately 0.25 inches, relative to impeller tip 106. To accommodate this, in the embodiment shown in
In some embodiments, before inserting pump assembly 100 into a patient, a clinician may insert a guidewire through the patient's vascular system to the heart to prepare a path for the operative device to the heart. In some embodiments, pump assembly 100 may include a GWG tube that may pass through a central internal lumen of pump assembly 100 from proximal guidewire opening in the distal end of FAT 112. The GWG tube may be pre-installed in pump assembly 100 to provide the clinician with a preformed pathway along which to insert a guidewire. Thus, in this embodiment, the guidewire may be advanced through a central lumen extending through the length of pump assembly 100. Other embodiments may include different types of guide features, as explained herein.
In one approach, the guidewire is first placed in a conventional way, e.g., through a needle into a peripheral blood vessel, and along the path between that blood vessel and the heart and into a heart chamber (e.g., into the left ventricle). Thereafter, a distal end opening of pump assembly 100 and/or a GWG tube may be advanced over a proximal end of the guidewire to enable delivery to pump assembly 100. After the proximal end of the guidewire is urged proximally within pump assembly 100 and emerges from a proximal guidewire opening and/or the GWG tube, pump assembly 100 may be advanced into the patient. In one method, the guidewire is withdrawn proximally while holding the catheter assembly.
Alternatively, the clinician may insert the guidewire through a proximal guidewire opening and urge the guidewire along the GWG tube until the guidewire extends from a distal guidewire opening (not shown) in the distal end of pump assembly 100. The clinician may continue urging the guidewire through the patient's vascular system until the distal end of the guidewire is positioned in the desired chamber of the patient's heart. A proximal end portion of the guidewire may extend from proximal the guidewire opening. Once the distal end of the guidewire is positioned in the heart, the clinician may maneuver a pump assembly over the guidewire until pump assembly reaches the distal end of the guidewire in the heart. The clinician may remove the guidewire and the GWG tube. In some embodiments, the GWG tube may also be removed before or after the guidewire is removed. Other embodiments for inserting a guidewire through different types of guide features are explained in more detail below.
After removing at least the guidewire, the clinician may activate a motor to rotate the impeller and begin operation of pump assembly 100. In some instances, when using the guidewire to guide the operative device to the heart, a central lumen or tube (e.g., a GWG) is typically formed to provide a path for the guidewire.
As shown in
In addition, GWG 102 may extend through a central lumen of pump assembly 100. Thus, GWG 102 may pass through the impeller shaft (not shown in
In some embodiments, GWG 102 does not extend distally past the end of the distal tip member at distal end 114. Rather, the central lumen passing through the distal tip member may include a proximal lumen and a distal lumen. The proximal lumen may have an inner diameter larger than an inner diameter of the distal lumen. A stepped portion or shoulder may define the transition between the proximal lumen and the distal lumen. The inner diameter of the proximal lumen is sized to accommodate GWG 102 as it passes through a portion of the distal tip member. However, the inner diameter of the distal lumen is sized to be smaller than the outer diameter of GWG 102 such that GWG 102 is too large to pass through the distal lumen of the distal tip member. In some embodiments, the thickness of GWG 102 may be made smaller than the height of the stepped portion or shoulder (e.g., smaller than the difference between the inner diameter of the proximal lumen and the inner diameter of the distal lumen). By housing GWG 102 against a shoulder, the shoulder may protect the outer coating of a guidewire when the guidewire is inserted proximally from the distal lumen to the proximal lumen.
Some embodiments may assist the clinician in inserting the guidewire into the distal end of pump assembly 100. For example, GWG 102 may be inserted through the central lumen of pump assembly 100. For example, GWG 102 may pass distally through a portion of the motor, the catheter body, the pump assembly, and cannula 110, and through the proximal lumen of the distal tip member. GWG 102 may be urged further distally until the distal end of GWG 102 reaches the shoulder. When the distal end of GWG 102 reaches the shoulder, the shoulder may prevent further insertion of GWG 102 in the distal direction (e.g., the shoulder may have a smaller diameter that the diameter of GWG 102). Because the inner diameter of the distal lumen is smaller than the outer diameter of GWG 102, the distal end of GWG 102 may be disposed just proximal of the. The shoulder may be made of a flexible material, which may result in expansion when a distal end of GWG 102 is pushed against the shoulder. In some embodiments, the shoulder may be coupled to a rigid ring that forms a non-deformable ledge. The ring facilitates maintaining the diameter of the shoulder and prevents GWG 102 from expanding the shoulder and moving beyond the shoulder.
The clinician may insert the proximal end of the guidewire proximally through a distal lumen passing through a rounded tip at the distal end of distal tip member. Because the distal tip member is flexible, the clinician may easily bend or otherwise manipulate the distal end of the distal tip member to accommodate the small guidewire. Unlike GWG 102, which may be generally stiffer than the distal tip member, the clinician may easily deform the distal tip member to urge the guidewire into the distal lumen. Once the guidewire is inserted into the distal lumen, the clinician may urge the guidewire proximally past stepped portion or shoulder and into larger GWG 102, which may be positioned within proximal to the lumen. Furthermore, since most commercial guidewires include a coating (e.g. a hydrophilic or antimicrobial coating, or PTFE coating), GWG 102 and the shoulder advantageously avoids damaging or removing the coating. When the wall thickness of GWG 102 is less than the height of the step or shoulder, the shoulder may substantially prevent GWG 102 from scraping the exterior coating off of the guidewire. Instead, the guidewire easily passes from the distal lumen to the proximal lumen. The guidewire may then be urged proximally through the impeller and catheter assembly until the guidewire protrudes from the proximal end of the system, such as through a proximal guidewire opening.
The GWG features may include a central lumen passing through pump assembly 100 along its length. In some embodiments, it may be desirable to omit the central lumen through pump assembly 100. For example, removing the central lumen from the drive cable and motor assembly may advantageously simplify the manufacturing process and may reduce the profile (e.g., diameter) of pump assembly 100.
As described herein, GWG 102 may include various embodiments of a distal portion of a GWG 102. As described above, GWG 102 may include a GWG tube (also referred to herein as a hypotube). The hypotube may include a relatively rigid hypodermic tubing made of stainless steel. The distal tip of the hypotube may be formed in different shapes and/or with varying angles. For example, the distal end of the hypotube may be narrower than other portions of the hypotube. The hypotube may include a polymeric sleeve or flexible tubular lumen, thereby making the distal end of the GWG tube (which contacts the inner lumen of sealing septum 108 and/or rigid transition, as shown in
The hypotube may include a sleeve (e.g., a polymeric sleeve or flexible tubular lumen) that may be extruded or constructed from any of a number of polymeric materials similar to a tip of a balloon, such as polyamide elastomers (similar to inner members of balloon catheters), polyethylene copolymers, PTFE blends, or combination thereof. The sleeve may be compliant, expandable, electrospun, braided, mesh-like, webbing-like, and/or similar to a wrap or tubular lumen. The sleeve may also be coated to further reduce friction between contact components such as distal septum 108. The coating may include silicone or mineral oil based materials, hydrophobic materials, hydrophilic materials, or other materials suitable for the coating sleeve to function, as described herein. Further, in some embodiments, the sleeve may include an end terminus that may include an oval or circular lumen that may expand during a guidewire insertion, for example, through GWG 102. The sleeve may also be straight-cut or angled to reduce the total surface area of material around the guidewire, potentially that would enlarge the distal septum during storage post-manufacturing prior to use.
The hypotube may also include a lased sleeve that may be constructed from a flexible alloy, such as nitinol or a grade of stainless steel (with exemplary compositions of 16% to 25% chromium and between 6% to 25% nickel). The lased sleeve may be cut with different patterns and may include a coating for reduced friction, in particular when in contact with distal septum 108. The lased sleeve may also include an end terminus that employs a cylindrical collar to ensure that no snagging on other components occurs. The lased sleeve may include a relatively smaller outer diameter at the end terminus and/or may include segments having different expansion capabilities.
GWG 102 may, in some embodiments, include combinations of expandable sleeves and lased transitions. For example, the hypotube may include a sleeve having both an expandable braided sleeve and a lased transition section. In some embodiments, the hypotube may include a lased expandable sleeve.
The hypotube described herein is more “septum friendly” than at least some known GWG tubes, since the hypotube has a distal tip that is more flexible and/or has a reduced footprint (e.g., smaller outer diameter), reducing friction between the hypotube and other components (e.g. tail, nose, distal septum 108, cannula 110, FAT 112, distal end 114 of the impeller (all shown in
Additionally, the hypotube may include diameters or gauge sizes smaller or larger than existing GWG tube outer diameters and/or inner diameters, in order to accommodate guidewires of varied dimensions dependent on coronary, peripheral, neurovascular, biliary, or alternate anatomies. For example, the dimensions of the hypotube may include an outer diameter ranging from 0.0120-0.0125 inches, a wall thickness of approximately 0.002 inches, and an inner diameter ranging from 0.0075-0.0090 inches.
In some embodiments, the hypotube includes a lased sleeve that may be constructed from a flexible alloy, such as nitinol, a grade of stainless steel, or advanced polymers, such as polyamide, HDPE, LLDPE, FEP, PET, Pebax, etc. The lased sleeve may be cut with different patterns and may include a coating for reduced friction, in particular when in contact with distal septum 108. The diameter of the lased sleeve may decrease across distal septum 108, allowing septum 108 to substantially close. In some embodiments, if distal septum 108 includes two or more elastomeric discs, the lased sleeve may also accommodate slight movement and/or deformation of the discs. Once the lased sleeve exits distal septum 108 distally, the lased sleeve expands back out to a larger diameter (which may be the same as or smaller than a diameter of portions of the associated hypotube that are proximal of distal septum 108).
Septa discs 210 and 230 may consist of a uniform elastomeric material capable of being easily punctured to form an aperture or opening. In some embodiments, more than one elastomeric material may be used. In some cases, two elastomeric materials of varying densities may be used. The specific type of material used may be determined by cost, manufacturing capability, pliability, and flexibility, among other considerations. In some embodiments, septa discs 210 and 230 are made of different materials. In some embodiments, septa discs 210 and 230 may be formed via shells with varying density internally such as a gel or gel-like substance.
Puncture tools of varying widths corresponding to the width of the guidewire and/or GWG 102 may be used to create a sufficient passageway. During storage of distal septum 108, GWG 102 remains in place across distal septum 108. One problem with a long storage shelf life is that for certain materials, such as a silicone elastomer, the material may creep such that when the GWG and/or guidewire are removed, distal septum 108 may not assume its original shape.
To minimize the effect of deformation in septa discs 210 and 230, puncture points at apertures 220 and 240 in each septa disc 210 and 230 through which the guidewire and/or GWG 102 are threaded facilitates improved impedance of fluid flow when septa discs 210 and 230 are positioned within the catheter assembly. As shown in
The embodiments described herein provide systems and methods for guidewire guides in implantable medical devices. Although certain embodiments of this disclosure 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 disclosure. 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 disclosure, and do not create limitations, particularly as to the position, orientation, or use of the disclosure. 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 disclosure as defined in the appended claims.
When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above constructions without departing from the scope of the disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
This application claims the benefit of priority to U.S. Provisional Patent Application No. 63/294,625, filed Dec. 29, 2021, the entire contents of which are hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 63294625 | Dec 2021 | US |
