Patent Application
20240180698
The present invention relates to the field of medical devices, and in particular to a delivery catheter, an implant delivery system and methods of operation.
Human heart valves include the aortic valve, the pulmonary valve, the mitral valve and the tricuspid valve. All these heart valves function like one-way valves to maintain continual blood flow in the human body in a specific direction, thereby establishing effective blood circulation. However, these heart valves may fail to function due to congenital defects, inflammation, degenerative aging or other reasons, leading to circulatory disorders which may cause severe damage to cardiac blood vessels and organs, or even death. In the current clinical practice, surgical repair or replacement provide the most effective treatment to defective native valves. However, conventional surgical valvuloplasty is much invasive, requires a long time for a patient to recover and tends to be associated with multiple complications. In contrast, interventional valvuloplasty can implant a valve prosthesis or an artificial heart valve at the location of a defective native valve to achieve a therapeutic effect in a less invasive way by delivering it through a large blood vessel in the patient's body.
Transcatheter aortic valve replacement (TAVR) is catheterized intervention procedure involving first crimping an artificial valve into a delivery system outside the patient's body and then delivering the artificial valve to the annulus of the patient's native aortic valve through a vascular or trans-apical access, followed by release of it at the location of the annulus in order to replace the native valve. At present, common artificial valves for use in TAVR applications are mainly self-expanding valves and balloon-expandable valves. Both these types of artificial valves are crimped into a delivery system before being delivery into a human body. During release, a self-expanding valve spontaneously expands to replace a defective native valve by virtue of temperature-dependent phase transitions of a specialized metal such as a nickel-titanium alloy from which a stent in the valve is fabricated. In contrast, a balloon-expandable valve is unfolded to replace a defective native valve by external forces exerted by through a balloon or another expansion tool.
Compared with self-expanding valves, balloon-expandable valves typically exhibit higher radial support and better roundness after release. However, since valve release must resort to external forces, the requirements on the delivery system used to achieve the release are more demanding so as to achieve a good match between the delivery system and prosthetic valve. Despite the rapid development of valve replacement techniques using balloon-expandable valves, there are still some challenges in the design of associated delivery systems. For example, it is difficult to ensure accurate and stable delivery and release of an artificial valve. With the existing designs, during the delivery and release of an artificial valve using a delivery system, there remains a risk of sudden axial movement of valve with respect to the delivery system, which, in severe cases, can possibly lead to incomplete or asymmetric unfolding of the artificial valve, or even damage to the delivery system and dislodgement of the valve.
It is an object of the present invention to provide a delivery catheter, an implant delivery system and methods of operation, which facilitate the resolution of the problem of a risk of sudden axial movement of an implant with respect to a delivery system and risks associated with release of the implant during delivery and release of the implant by the delivery system.
It is another object of the present invention to overcome the problem of a risk of sudden axial movement of an implant with respect to a delivery system and risks associated with release of the implant during delivery and release of the implant by the delivery system.
To this end, the present invention provides a delivery catheter comprising a catheter, a balloon structure and a guidewire tube, the balloon structure disposed at a distal end of the catheter, the guidewire tube inserted within the catheter and the balloon structure, the balloon structure comprising an expandable component and a balloon body, the expandable component disposed within the balloon body so as to be expandable therein, the expandable component disposed at a distal end of the guidewire tube, with an implant being sleeved over the balloon body and being axially restrained over a middle portion of the expandable component during delivery, the expandable component configured to provide a radially outward support force from a middle portion of the balloon body during expansion so as to bring internal environments of the balloon body respectively at distal and proximal end thereof into communication.
Optionally, the implant may comprise an artificial valve.
Additionally, the balloon structure may further comprise a proximal support member and a distal support member, which are both provided within the balloon body, wherein each of the proximal and the distal support members has a same axial direction as the expandable component, the proximal support member sleeved over a proximal end of the expandable component, the distal support member sleeved over a distal end of the expandable component, wherein the artificial valve is axially restrained between the proximal and distal support members during delivery.
Additionally, the expandable component may be an inflatable balloon body comprising a first section, a second section and a third section, that are sequentially connected from its proximal to distal end, the first section inserted within the proximal support member and proximally connected to an inner wall of the catheter, the third section inserted within the distal support member and distally connected to an outer wall of the guidewire tube, the second section located between the proximal and distal support members, wherein the artificial valve is arranged over the second section during delivery.
Additionally, each of the first section and the third section may have at least one indentation stripe arranged circumferentially, wherein the at least one indentation stripe is provided on an outer wall of the inflatable balloon body, and wherein an extension direction of the indentation stripe is as same as an axial direction of the inflatable balloon body.
Additionally, the indentation stripe may comprise at least one indentation spaced axially.
Additionally, the expandable component may be a secondary balloon, a distal end of the secondary balloon is inserted within the distal support member and is connected to the outer wall of the guidewire tube, and wherein a proximal end of the secondary balloon is inserted within the proximal support member and communicates with the catheter.
Additionally, the proximal support member may be a tubular structure open at both ends, a tapered resilient member or a multi-ridge clamp, and the distal support member may be a tubular structure, a resilient member or a multi-ridge clamp.
Additionally, in case of the proximal support member and/or the distal support member being tubular structure(s), a plurality of through-pores may be even distributed on an outer circumferential surface of the tubular structure(s).
In case of the proximal support member and/or the distal support member being tapered resilient member(s), tapered resilient member(s) may comprise a maximum diameter at its end proximal to the artificial valve.
In a second aspect, the present invention provides an implant delivery system comprising the delivery catheter as defined above.
In a third aspect, the present invention provides a method for operating the implant delivery system, in which the expandable component is implemented as the inflatable balloon body as defined above. The method includes:
In a fourth aspect, the present invention provides a method for operating the implant delivery system, in which the expandable component is implemented as the secondary balloon as defined above. The method includes:
Compared with the prior art, the present invention has at least the following benefits:
1. The expandable component provides a radially outward support force from the middle portion of the balloon body during expansion so as to bring the internal environments of the balloon body respectively at the distal and proximal end thereof into communication. This facilitates stable and uniform and hence symmetric expansion of the implant.
2. The implant is axially restrained between the proximal and distal support members and thus prevented from sudden axial movement with respect to a delivery and release once it is crimped onto the expandable component (e.g., the inflatable balloon, or the secondary balloon).
3. The indentations provided in the inflatable balloon on the opposite ends of the implant enable the internal environments of the balloon body respectively at the proximal and distal ends thereof to be brought into communication with each other during release of the implant. In this way, the balloon body can be inflated simultaneously at the proximal and distal ends, avoiding inadvertent dislodgement of the implant due to inflation of the balloon body non-simultaneously at the proximal and distal ends thereof. When the indentations in the expandable component are torn at a high pressure, the inflation fluid will flow into the balloon body through the indentations at the same rate and the same pressure, thereby inflating the balloon body simultaneously at the proximal and distal thereof. This enables stable and uniform and hence symmetric expansion of the implant.
In these figures,
Delivery catheters, implant delivery systems and methods of operation proposed herein will be described in greater detail below. The present invention will be described in greater detail below with reference to the accompanying drawings, which present preferred embodiments of the invention. It would be appreciated that those skilled in the art can make changes to the invention disclosed herein while still obtaining the beneficial results thereof. Therefore, the following description shall be construed as being intended to be widely known by those skilled in the art rather than as limiting the invention.
For the sake of clarity, not all features of actual implementations are described. In the following, description and details of well-known functions and structures are omitted to avoid unnecessarily obscuring the invention. It should be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made to achieve specific goals of the developers, such as compliance with system-related and business-related constrains, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art.
Objects and features of the present invention will become more apparent upon reading the following more detailed description thereof made with reference to the accompanying drawings and to particular embodiments. Note that the figures are provided in a very simplified form not necessarily drawn to exact scale and for the only purpose of facilitating easy and clear description of the disclosed embodiments. As used herein, the term “or” is generally employed in the sense of “and/or”, unless the context clearly dictates otherwise. As used herein, the terms “inner”, “outer” and similar terms are merely illustrative and do not represent the only implementation possible. As used herein, the terms “proximal end” and “distal end” are employed to describe relative orientations, relative positions and directions between components of a medical device or actions thereof, as viewed by a physician operating the device. Without wishing to be limiting, a “proximal end” usually refers to an end closer to the operator, and a “distal end” usually refers to an end closer to the heart of a patient, during normal operation of the medical device.
In principle, the present invention seeks to provide a delivery catheter, an implant delivery system and methods of operation. The delivery catheter includes a catheter, a balloon structure and a guidewire tube. The balloon structure is provided at a distal end of the catheter, and the guidewire tube is inserted within the catheter and the balloon structure.
The balloon structure includes an expandable component and a balloon body. The expandable component is disposed within the balloon body and is sleeved over a distal end of the guidewire tube. An implant is arranged on the balloon body and is axially restrained over a middle portion of the expandable component during a delivery process. The expandable component is configured to provide a radially outward support force from the middle portion of the balloon body and thereby bring internal environments of the balloon body respectively at its distal and proximal ends into communication with each other during an expansion process.
When the delivery catheter is an inflatable balloon, a method for use with the implant delivery system includes:
When the delivery catheter is a secondary balloon, a method for use with the implant delivery system includes:
As shown in
The delivery catheter includes a catheter, a guidewire tube and a balloon structure. The guidewire tube is inserted within and through the catheter, and a distal end of the guidewire tube protrudes out of a distal end of the catheter. A diameter of the guidewire tube is smaller than a diameter of the catheter, allowing an inflation fluid to flow into the catheter from a proximal end thereof over the guidewire tube and out of the catheter from the distal end of the catheter. The balloon structure is configured for loading and delivery of the artificial valve and provided at the distal end of the catheter. The balloon structure is sleeved over a distal end of the guidewire tube.
The balloon structure includes a proximal support member, a distal structure, an inflatable balloon and a balloon body. The proximal support member is disposed at the proximal end of the catheter, and the distal structure is provided at the distal end of the guidewire tube. The inflatable balloon is sleeved over the guidewire tube and is proximally inserted within the proximal support member. Moreover, the inflatable balloon is distally inserted within the distal structure. The balloon body is sleeved over the proximal support member, the distal structure and the inflatable balloon, and is proximally fixed to an outer wall of the catheter. Further, the balloon body is distally fixed to an outer wall of the distal structure.
The proximal support member is fixedly connected to the proximal end of the catheter by welding, adhesive bonding or integral injection molding. The proximal support member may be a tubular structure open at both ends. Preferably, multiple through-pores are provided in a circumferential surface of the tubular structure (i.e., a multi-pore tubular structure, as particularly shown in
The distal structure is sleeved over the distal end of the guidewire tube and includes, axially connected together in sequence from its proximal to distal end, a distal support member, a connecting portion and a tapered tip. The tapered tip has a diameter gradually decreasing from its proximal to distal end, which facilitates introduction of the delivery catheter to a blood vessel. Preferably, the balloon body is distally fixed to an outer wall of the tapered tip around the proximal end of the tapered tip. The tapered tip comprises a lumen extending axially therethrough. Both the distal support member and the connecting portion may be tubular structures open at both ends. An outer diameter of the connecting portion may be smaller than an outer diameter of the distal support member, and an inner diameter of the connecting portion may be smaller than an inner diameter of the distal support member and may be slightly greater than an outer diameter of the guidewire tube. An outer surface of the guidewire tube may be adhesively bonded to an inner surface of the connecting portion and terminate at a distal end of the connecting portion. The guidewire tube may be coaxial with the lumen to allowing smooth passage of a guidewire therethrough.
Preferably, multiple through-pores are provided in a circumferential surface of the distal support member (i.e., a multi-pore tubular structure, as particularly shown in
The inflatable balloon is distally inserted within the distal structure and fixedly connected by welding, bonding or otherwise to an outer wall of the guidewire tube at the distal end thereof so that the inflatable balloon is closed at a distal end of the balloon structure. The inflatable balloon may be proximally inserted within the catheter and fixedly connected by welding, bonding, anchoring or otherwise to an inner wall of the catheter around the distal end thereof, allowing an inflation fluid introduced into the catheter to enter the inflatable balloon from the proximal end of the inflatable balloon and flow distally.
The inflatable balloon may have an elongate shape, particularly such as a cylindrical, lageniform or cuboid shape. The inflatable balloon may have the same axial direction as the guidewire tube. Preferably, the inflatable balloon is cylindrical. The inflatable balloon may be made of a polymeric material, such as PA, PE, PP, PEBAX or silicone rubber. Preferably, the inflatable balloon is made of PA.
As shown in
Each of the first and third sections of the inflatable balloon has at least one indentation stripe on an outer wall thereof. Preferably, there are 2-6 indentation stripes on the outer wall of each of the first and third sections of the inflatable balloon. All the indentation stripes are even spaced apart circumferentially around the first and third sections and extend in the same axial direction as that of the inflatable balloon.
As shown in
During use, at first, as shown in
In a second embodiment, a secondary balloon is used in place of the inflatable balloon in the first embodiment.
During use, an artificial valve is crimped onto the balloon body by an external force. At this stage, the balloon body is brought into a collapsed configuration without any inflation fluid in the secondary balloon. In this configuration, the artificial valve is fully crimped and fit against the outer side of the balloon structure and be axially restrained between the proximal support member and the distal structure. Next, an inflation fluid is introduced from a proximal end of the corresponding catheter to the secondary balloon to inflate the secondary balloon. As a result, the secondary balloon slightly expands the artificial valve outwardly, thereby bringing internal environments of the balloon body at proximal and distal ends thereof into communication with each other. After that, the secondary balloon is deflated. Subsequently, the inflation fluid is introduced from a proximal end of the corresponding catheter to the balloon body to inflate the balloon body until the balloon body is uniformly inflated to its maximum size. This enables stable release of the artificial valve.
In summary, in the delivery catheter, implant delivery system and method of the present invention, through arranging the proximal support member and the distal structure, the risk of sudden axial movement of an implant with respect to the delivery system during delivery and release can be avoided. Moreover, microstructures can be etched in the expandable component to enable the implant to be slightly expanded to bring the internal environments of the balloon body at the proximal and distal ends thereof into communication. This greatly reduces the risk of dislodgement of the implant due to non-simultaneous inflation. Further, the etched portions of the expandable component (e.g., the inflatable balloon or the secondary balloon) can be torn under a high pressure, enabling an inflation fluid to simultaneously enter the internal environments of the balloon body respectively at the proximal and distal ends thereof at the same rate and the same pressure. In this way, the implant can be expanded uniformly in a stable manner, solving the problem of incomplete or asymmetric expansion of the valve during release.
It is to be noted that, as used herein, the terms “first” and “second” are only meant to distinguish various components, elements, steps, etc. from each other rather than indicate logical or sequential orderings thereof, unless otherwise indicated or specified.
It is to be understood that while the invention has been described above with reference to preferred embodiments thereof, it is not limited to these embodiments. In light of the above teachings, any person familiar with the art may make many possible modifications and variations to the disclosed embodiments or adapt them into equivalent embodiments, without departing from the scope of the invention. Accordingly, it is intended that any and all simple variations, equivalent changes and modifications made to the foregoing embodiments based on the substantive disclosure of the invention without departing from the scope thereof fall within this scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202111145941.0 | Sep 2021 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/113498 | 8/19/2022 | WO |
