Patent Application
20220387768
The present disclosure relates generally to catheters, and more particularly to balloon catheters and methods of manufacturing the same.
Various forms of balloon catheters are used in a wide range of medical procedures, such as percutaneous transluminal coronary angioplasty (PTCA), endovascular exclusion of abdominal aortic aneurysm (AAA) using stent grafts, and others. Balloon catheters can include two separate lumens, namely a guidewire lumen for traveling across a guidewire to and from a desired location within the artery, and a fluid lumen (e.g., air lumen) for delivering airflow to inflate the balloon. During a procedure, the balloon catheter is inserted and guided along the guidewire. The balloon catheter has an inflatable balloon at its tip. Once inserted, air can be pumped into the balloon to enlarge a narrow opening or passage within the vasculature.
According to one embodiment, a method of manufacturing a balloon catheter comprises: providing a fluid tube between an inner surface of a catheter tube and an outer surface of the catheter tube, wherein the fluid tube defines an fluid lumen therein extending along a longitudinal direction of the catheter tube; and shearing a portion of the catheter tube and the fluid tube to create a hole in the catheter tube that allows fluid communication between the fluid lumen to a balloon external to the outer surface of the catheter tube, wherein the shearing is performed in a direction lateral to the longitudinal direction of the catheter tube.
According to an embodiment, a method of manufacturing a balloon catheter comprises: providing a fluid tube between an inner surface of a catheter tube and an outer surface of the catheter tube, wherein the fluid tube defines a fluid lumen therein, and wherein the catheter tube extends along a central axis that lies on a bisecting plane; and shearing a portion of the catheter tube and the fluid tube to create a hole in the catheter tube that allows fluid communication between the fluid lumen and a balloon external to the outer surface of the catheter tube, wherein the shearing is performed in a direction parallel to the bisecting plane.
According to an embodiment, a balloon catheter comprises: a catheter tube having an inner surface and an outer surface, wherein the catheter tube defines a main lumen therein extending along a main axis, and wherein the catheter tube defines a hole therein that extends through the outer surface; and a fluid tube located between the inner surface of the catheter tube and the outer surface of the catheter tube, wherein the fluid tube defines a fluid lumen extending parallel to the main axis, and wherein the hole fluidly connects the fluid lumen to a balloon located outside the outer surface of the catheter tube; wherein a cross section of the catheter tube at the hole is in a circular segment shape.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
Directional terms used herein are made with reference to the views and orientations shown in the exemplary figures. A central axis is shown in the figures and described below. Terms such as “outer” and “inner” are relative to the central axis. For example, an “outer” surface means that the surfaces faces away from the central axis, or is outboard of another “inner” surface. Terms such as “radial,” “diameter,” “circumference,” etc. also are relative to the central axis. The terms “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made.
Unless otherwise indicated, for the delivery system the terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to a treating clinician. “Distal” and “distally” are positions distant from or in a direction away from the clinician, and “proximal” and “proximally” are positions near or in a direction toward the clinician. For the stent-graft prosthesis, “proximal” is the portion nearer the heart by way of blood flow path while “distal” is the portion of the stent-graft further from the heart by way of blood flow path.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description is in the context of treatment of blood vessels such as the aorta, coronary, carotid and renal arteries, the invention may also be used in any other body passageways where it is deemed useful.
Various forms of balloon catheters are used in a wide range of medical procedures. Such procedures include, for example, angioplasty, such as percutaneous transluminal coronary angioplasty (PTCA), endovascular exclusion of abdominal aortic aneurysm (AAA) using stent grafts, and others. Balloon catheters can include two separate lumens, namely a guidewire lumen (also referred to as a main lumen) for traveling across a guidewire to and from a desired location within the artery, and a fluid lumen (e.g., air lumen) for delivering airflow to inflate the balloon. During a procedure, the balloon catheter is inserted and guided along the guidewire. The balloon catheter has an inflatable balloon at its tip. Once inserted, fluid such as air or saline can be pumped into the balloon to enlarge a narrow opening or passage within the vasculature.
During a process of endoluminal AAA repair using a stent graft (as an example), a balloon catheter can be used to appropriately seat the stent graft in a desired location within the vasculature. In general, stent grafts for treatment of vascular aneurysm and blood vessel walls which have been thinned or thickened by disease (endoluminal repair or exclusion). Many stents and stent grafts are “self-expanding” in that they may be inserted into the vasculature in a constricted configuration, and are biased to expand radially outwardly once an outer sheath containing the stent graft is removed. To avoid endoleaks, a balloon on a balloon catheter can be used to properly seat the stent-graft against the blood vessel wall or walls.
A balloon catheter 10 is shown in
The inner layer 24 may be annular in shape to define the main lumen 28 therein. The inner layer 24 may be made of a polymeric material, for example, a synthetic tetrafluoroethylene such as polytetrafluoroethylene (PTFE). The inner layer 24 may also be provided with a braid structure for structural rigidity and support. The braid may be made of metal, such as stainless steel, for example.
The outer layer 26, also referred to as an outer jacket, may be annular in shape and fully encapsulate or circumscribe the inner layer 24. The outer layer 26 may be made of a thermoplastic elastomer (TPE) such as a polyether block amide (PEBA). One example of PEBA is known under the tradename PEBAX. The outer layer may include two materials bonded together at a connection 30. In particular, the outer layer 26 may include a first material 32 made of TPE such as PEBA, and a second material 34 made of TPE such as PEBA. The first material 32 is located more towards the distal end of the balloon catheter 10 and therefore may be thicker and/or less rigid than the second material 34 to provide proper flexibility at the tip of the balloon catheter 10 which may be beneficial during insertion through the vasculature.
The balloon catheter 10 also includes a fluid tube, also referred to as an air tube 36. While references herein are made to “air” being delivered through the air lumen 36, it should be understood that any other suitable fluid—either liquid or gaseous—can be used to inflate the balloon depending on the particular device and medical procedure used. The structure described herein can be implemented in both an air balloon or a fluid (e.g., saline) balloon, and references to an air lumen or air balloon are not intended to be limited to requiring the use of air to inflate the balloon 18.
The air tube 36 defines an air lumen therein configured to deliver air to the balloon 18 from, e.g., the balloon inflation device 12. The air tube 36 may be made of a high-performance plastic or polymer, such as polyimide. The air tube 36 may be embedded within the outer layer 26 of the main tube 22, and may be at least partially circumscribed by the outer layer 26. In other embodiments, the air tube 36 is an air lumen formed by removing material from the outer layer 26 of the main tube 22. In other words, the air tube can be defined within the material of the main tube 22 rather than being a separate component embedded within the main tube 22.
At a distal end of the air tube 36 are a plurality of holes 38. The holes 38 allow the air from the air tube 36 to inflate the balloon 18. In other words, the holes 38 extend through a portion of the outer layer 26 and into air tube 36 to expose the air tube 36 to the environment outside of the main tube 22. Therefore, as air is forced into the air tube 36, it escapes the air tube 36 into the balloon 18 via the holes 38.
During manufacturing, the inner layer 24 and the air tube 36 may be joined together by lamination, overmolding, or co-molding of the outer layer 26. This embeds the air tube 36 within the outer layer 26. Due to this manufacturing process, the holes 38 are then later cut or formed into the outer layer 26. However, this can be challenging because cutting the holes 38 at a direction toward the center of the air tube 36 requires an extremely fine depth control so as to not pierce through to the main lumen 28. Additionally, direct cutting or piercing involves risks of the removed material becoming caught in the air tube 36, potentially causing a blockage.
Therefore, according to various embodiments described herein, the holes 38 are formed by cutting in a lateral direction.
Referring to
Due to the direction of cutting at 40, the main tube 22 of the balloon catheter generally assumes a circular segment shape (although as described above, the outer layer 26 may not be a perfect circle). In particular, the cutting direction 40 creates cutting surfaces 46 on either lateral side of the air tube 36. The cutting surface 46 appear to be flat when viewing from a cross-sectional view as shown in
The transverse cutting—e.g., cutting across the length of the main tube 22 such as parallel to a tangent of the main tube 22—can create uniform depth along the cutting direction. In other words, the height of the outer layer 26 can be uniform along any line that is parallel to the cutting direction. Referring to
The balloon catheter 10 can therefore be said to be manufactured as follows, according to an embodiment. The air tube can be embedded (laminated, overmolded, co-molded, wrapped, etc.) within the outer layer 26 of the catheter tube 16 (or main tube 22), between the inner surface 42 of the catheter tube 16 and the outer surface 44 of the catheter tube 16. Thereafter, an operator or machinery can cut or shear a portion of both the catheter tube 16 and the air tube 36 along a direction 40 that is lateral to the longitudinal direction of the catheter tube 16.
The cutting that removes the material above line 48 can be performed by any number of suitable tools. In one embodiment, a drill cutter having a rotating bit with a sharpened point can be activated to spin and press into the outer layer 26 to remove the material. In other embodiments, blades or the like can be used to cut a straight, flat cutting edge.
Referring to
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
