KR20050016954A - Ballon catheter - Google Patents

Abstract

The present invention relates to a shaft comprising a relatively rigid adjacent shaft section that is primarily tubular, and an end shaft section attached to a distal end of the adjacent shaft section and more flexible than the adjacent shaft section, and an expandable portion extending from the distal end of the distal shaft section. A ballon catheter, comprising a balloon, is attached to a distal end of an adjacent shaft section extending into the distal shaft section. The balloon catheter is employed in the field of coronary angioplasty, in particular percutaneous transluminal coronary angioplasty (PTCA).

Description

BALLON CATHETER}

The present invention relates to a shaft comprising a tubular relatively rigid proximal shaft section and a distal shaft section attached to the distal end of the adjacent shaft section and more flexible than the adjacent shaft section, and at the distal end of the distal shaft section. An expandable balloon which extends, wherein the adjacent shaft section and the distal shaft section form an expansion lumen extending therein that is in fluid communication with the interior of the balloon to apply an expansion pressure to the balloon; The distal shaft section includes a guide wire lumen for receiving a guide wire, the guide wire lumen disposed at an end relative to the bolon and the guide wire inlet disposed between the end of the adjacent shaft section and the ballon and of the catheter Guide wire exit to the outside Is, to a, bolrun catheter distal end of adjacent shaft segments which have a flexible transition member is attached extends into the distal shaft segment. In particular, the present invention has a so-called " rapid exchange over-the-, " having a relatively short distal guide wire that extends through part of the distal shaft section, comprising a ballon region. wire) "dilatation ballon catheter. Such balun catheter is widely used in the field of coronary angioplasty, in particular percutaneous transluminal coronary angioplasty (PTCA).

Plastic surgery procedures have been widely recognized as an effective and effective way to treat various types of vascular disease. In particular, the formation technique can be used to treat stenosis in other parts of the body, but is widely used to open stenosis in the coronary arteries. The most widely used form of angioplasty requires an expansion catheter that bears an inflatable balloon on its distal end. Typically, a hollow guide catheter is placed percutaneously initially in the patient's femoral artery and advances down the aorta over the aortic arch and into the upward aorta, which is guided from the heart. The distal end of the guide catheter is specially shaped such that the distal tip of the guide catheter can be easily placed at the entrance to the right or left coronary artery. This guide catheter is used to quickly guide the dilation catheter through the vasculature to a position slightly past the inlet. The physician uses fluoroscopy to guide the dilation catheter to the remaining distance across the largely curved portion of the trajectory through the vasculature until the balloon is positioned intersecting the constriction. The balloon is then inflated by supplying fluid under a predetermined pressure through an expansion lumen extending from the proximal end of the catheter into the balloon. The expansion of the balloon should cause scratches in the arteries and damage within the artery walls, rereeblblishing acceptable blood flow through the arteries.

In order to be able to easily reach the treatment site, the catheter preferably meets a number of opposing requirements. Above all, the catheter must be pushable so that the pushing force exerted on its distal end may actually be delivered to the distal tip. In addition, torque forces need to be transmitted as undisturbed as possible throughout the catheter in order to improve the steering and responsiveness of the device. This transfer of forces is carried out by a rigid and stiff catheter shaft. However, the catheter must also be flexible enough to follow the natural anatomy of the vasculature, particularly the largely curved trajectory in the coronary region and to reach the stenosis. In general, the latter is referred to as the catheter's tracability. In order to comply with all of these requirements, a balun catheter of the kind described at the outset has a terminal section flexible enough to conform to the natural anatomical structure of the coronary artery, providing the required progression, and the required pushability and steering capability. It includes a complex shaft design with a more rigid adjacent shaft section that provides.

A balloon catheter with such a composite catheter is known, for example, from European patent application 580.845. The catheter comprises an adjacent shaft section formed by a tube formed from a hypodermic metal, followed by a distal shaft section consisting of a plastic tubing that is substantially more flexible than the adjacent shaft section. A relatively rigid metal tube can transfer pushing and steering forces with little or no loss from its immediate end to the distal end in an already small profile to provide the catheter's pushability and steering, but is so rigid that it bends significantly Can't follow coronary arteries. In practice, however, only the adjacent shaft section reaches the entrance to the right or left coronary artery with a substantially linear trajectory. On the other hand, the flexible plastic tubing forming the distal shaft section extends beyond the inlet, but is sufficiently bendable to follow the curvature of the coronary vessel.

While the composite shaft design as described above can achieve the required push capability and steering on the one hand and the required progression on the other hand, there is a relatively large difference in the rigidity between the adjacent shaft section and the distal shaft section, The transition between both shaft segments, in particular the guide wire lumen, makes the catheter relatively vulnerable to kinking and buckling in areas that are not supported by the guide wire being inserted. This reduces the responsiveness and push ability of the catheter and can cause significant closure of the expansion lumen from the adjacent shaft section to the distal shaft section. It is clear that the blocked expansion lumen will render the catheter useless.

In order to solve these problems associated with the transition between the relatively rigid, metal adjacent shaft section and the remarkably more flexible end shaft section, the known catheter is a transition member in the form of a core wire for connecting the gap between the adjacent shaft section and the guide wire lumen. It includes. This core wire provides support to the other unsupported portion of the distal shaft section. If the guide wire is received in the guide wire lumen so that the catheter can be substantially supported along its entire length, the remaining portion of the distal shaft section will be supported by the guide wire. This significantly reduces its tendency to bend or buckle in certain areas. However, in order to connect the core wire to the adjacent shaft section, it is slightly inserted into the distal end of the metal tube and soldered to its inner wall. As such, when it extends within the expansion lumen that extends through the metal tube, it presents a significant obstacle to the expansion fluid. Moreover, adjacent portions of the core wire extending in the metal tube are very difficult to use soldering, which leads to poor bonding and poor connection reliability.

1 is a longitudinal cross-sectional view of one embodiment of a balloon expansion catheter according to the present invention;

2 is a detailed view of a portion of the catheter of FIG. 1;

3 is a detailed cross-sectional view of the transition element applied in the catheter of FIG. 1;

4 is a perspective view of the transition element of FIG. 3.

It is to be understood that the drawings are not drawn to scale. In particular, some dimensions may have been somewhat exaggerated to aid in understanding. In the figures, corresponding or similar parts are generally indicated with the same reference numerals.

In essence, the object of the present invention is of the kind described above at the outset, without the problems described above with respect to known catheters and with a reduced tendency of bending, kinks or buckling inside the guiding catheter during the course of the patient's body. To provide a balloon catheter.

According to the invention, a ballon catheter of the kind described at the outset is characterized in that the distal end of the adjacent shaft section is skived and the transition member is secured to the adjacent shaft section substantially along all of the skived portions of the distal end of the adjacent shaft. It features. The skived ends of the adjacent shaft sections provide a very easily accessible connection area to promote reliable bonding between the transition member and the adjacent shaft section. Since the inflation fluid is generally free to flow around and past the transition in the region, the inflation fluid does not suffer noticeable disturbances while the balloon is expanded at the distal tip of the catheter. The transition member significantly offsets the twisting and buckling of the catheter by supporting the catheter shaft over other unsupported areas between adjacent shaft sections and guide wire lumens. As such, the catheter in accordance with the present invention provides an extended catheter of a sleek profile with special mechanical and dynamic features.

In a preferred embodiment, the catheter according to the invention is characterized in that the adjacent end of the transition member extends inside the tubular portion of the adjacent shaft section, while the adjacent end of the transition member contacts the inner wall of the tubular portion of the adjacent shaft section. It is characterized by having a cross section smaller than the portion of the transition member disposed at the distal end. Thus, the transition member provides a continuous, integral support of the weakened skived portion of the adjacent shaft section to avoid twisting the catheter in the region. The particular cross-sectional profile of the transition member adjacent end reduces the obstacles that may be produced by the transition member inside the tubular portion of the adjacent shaft section. Nevertheless, as a result, expansion fluid can flow freely past the transition member. In another preferred embodiment, the catheter according to the present invention is characterized in that the transition member comprises a core wire, wherein a notch is provided at a proximal end of the core wire across the inner wall of the tubular portion of the adjacent shaft segment. It is characterized by. This notch reduces the flow resistance of the expansion fluid while maintaining the contact area between the core wire and the adjacent shaft section.

In order to facilitate a gradual increase in the flexibility of the distal shaft section, a preferred embodiment of the catheter according to the invention is characterized in that at least the distal end of the transition member has a diameter that generally dissipates in the distal direction. In general, the generally dissipated diameter is adapted to progressively dissipate the firmness of the portion of the catheter shaft. As such, sudden changes in robustness should be avoided or else may cause some vulnerability to buckling and kink again. The distal end of the transition member is preferably disposed at the distal end rather than the inlet to the guide wire lumen so that the transition member loses its rigidity too much and the guide wire is taken over the support of the catheter shaft which is difficult to accomplish the purpose.

Although the transition member and the adjacent shaft section are connected in different ways, very good results have also been obtained by the particular embodiment of the catheter, in which the transition member and the distal end of the adjacent shaft section are joined together.

The invention will now be described in more detail with reference to examples and accompanying drawings.

The catheter of FIG. 1 comprises, at its nearest end, an adjacent shaft section 10 carrying a so-called Luer fitting 1 which connects the catheter to the expansion mechanism in a conventional manner. The instrument allows for proper delivery of the inflation fluid under pressure guided into the inflation balloon 23 provided at the distal end of the catheter via an inflation lumen 2 extending in the catheter.

Indeed, the catheter advances to the entrance of one of the coronary arteries through an intraocular catheter (not shown) inside the patient's vasculature. The adjacent shaft section 10 of the catheter extends approximately along the entire length of the guide catheter. In order to improve pushability and steerability, the catheter is relatively rigid and stiff so that the forces exerted on its adjacent end can be transferred to the distal end with little or no loss. Is preferred. Thus, according to the invention, a metal tubular member 11 is used at the adjacent shaft end of the catheter. In this embodiment, the member 11 is a hypodermic metal, coated with a lubricity coating 12 to reduce the amount of friction between the inner wall of the guide catheter and the dilatation catheter, so-called Made of hypotubes. This coating is a thin layer of Teflon Or other lubricating plastics or polymers, but other materials are feasible within the scope of the present invention. This hypotube assembly significantly reduces the catheter's tendency to bend or buckle inside the guide catheter while the catheter is being pushed forward. However, the bending properties of smaller coronary arteries require much greater flexibility to allow the catheter to flow through the natural anatomy of these vessels.

Thus, the catheter includes a much more flexible end shaft section 20 to provide so-called trackability. In this embodiment, the distal shaft section comprises an intermediate sleeve segment 21 and a balloon segment 22. Both parts 21 and 22 of the end shaft section 20 are made of low density polyethylene, polyvinylchloride, nylon or other suitable plastics, which are flexible enough to cope with any bending in the coronary arteries. . The intermediate sleeve segment is connected directly to the adjacent shaft section 10 and into the guidewire lumen 30 extending inside the distal shaft section 20 of the catheter parallel to or in this case with the expansion lumen, Adjacent entry port 31. This portion of the catheter is shown in more detail in FIG. 2 of the drawings.

The guidewire lumen 30 receives, in use, a guide wire 3, the majority of which extends alongside the adjacent shaft section 10 of the catheter and the remainder extending inside the guidewire lumen 30. The guidewire (3) enters the guidewire lumen (30) through the guidewire lumen inlet (31) in an intermediate sleeve section (21) disposed between the distal end of the adjacent shaft section (11) and the ballon centrifugal (22), Exit the catheter through the guidewire lumen exit 32 at the distal end of the catheter. The guidewire 3 is used to quickly replace the catheter with another if necessary. Once the guidewire 3 is held in place, the catheter can be pulled back to be replaced by another and relatively quickly moved to the treatment spot by simply sliding it across the guidewire. As a result, the guidewire 3 directly guides the catheter to the right position. Because of this feature, the current type of catheter is often referred to as a rapid exchange over-the-wire catheter.

The balloon section carries the inflatable balloon 23. The interior of the balloon 23 is in fluid communication with the expansion lumen 2 extending entirely downward from the Luer fitting 1 into the balloon segment 22 of the catheter end section 20 via adjacent shaft sections and intermediate sleeve sections. . The balloon is made from a suitably preformed plastic sleeve that can withstand large internal pressures. Upon application of inflation pressure, the balloon is expanded to a predetermined inflation diameter and correspondingly the tube is widened. A metallic stent member (not shown) may be provided throughout the balloon and expands with the balloon to be left behind in the tube to provide continuous support of the tube wall after treatment.

In order to prevent kinky catheter at the transition from the relatively rigid adjacent shaft section 10 to the more flexible distal shaft section 20, a transition member 40 is provided to provide the hypotube 11 and the guide. Support other unsupported areas of the catheter between the wire lumen inlets 31. When the guidewire 3 is inserted into the guidewire lumen 30, the transition member 40 connects the gap in the catheter shaft between the metal hypotube 11 and the metal guidewire 3. In this embodiment, the transition member 40 comprises a metal core wire that is generally flexible between that of the adjacent shaft section 10 and the distal shaft section 20. The core wire 40 is firmly connected to the hypotube 11 by soldering, gluing or other suitable means. Core wire 40, having a length of approximately 286 mm, is ground beyond the guidewire lumen inlet 31.

According to the invention, the hypotube 11 is skived at its distal end, providing a sufficient contact area for reliable bonding between the core wire 40 and the hypotube 11. The skived portion of the hypotube extends over a predetermined length between approximately 60 mm and 70 mm to accommodate the adjacent end of the core wire 40. The skived end of the hypotube not only provides the required contact area, but also exposes the contact area so that it is easily accessible for the connection technique to be used. In this embodiment, the core wire 40 is adhered to the hypotube 11 by a UV curling adhesive. Due to the skived portion, the entire contact area can be exposed to UV curing radiation. Moreover, since the expansion fluid is no longer confined to the interior of hypotube 11 in the skived region, it can flow freely past core wire 40. As a result, the core wire 40 does not provide a substantial obstacle to the inflation fluid while the balloon 23 is being inflated.

Due to the skived structure, the hypotube 11 loses a significant amount of its stiffness in its distal region. In order to avoid any kinks in the skived ends of the hypotubes, the core wire 40 extends slightly inside the tubular portion, i.e. the bisking portion of the hypotubes, to provide overall support. In this embodiment, the proximal end of the core wire 40 lies over about 3-5 mm inside the tubular portion of the adjoining shaft section 10. In order to eliminate substantial obstruction of the inflation fluid, which may be caused in this manner, a notch 41 is provided at an adjacent end of the core wire 40 (see FIGS. 3 and 4). The notch 41 is approximately 5-7 mm and clears up to approximately 50% of the cross-sectional area of the core wire so that the expansion fluid is not disturbed from the Luer fitting 1 to the ballon 23 or vice versa. Enough to allow unflowable flow. The notches 41 are provided across the side from the contact area between the inner wall of the adjacent shaft section 10 and the core wire 40 to maintain a sufficient area of reliable joint. Also, instead of the notch 41, a transition member 40, which is adapted to extend slightly inside the tubular portion of the adjacent shaft section 10, with a cross-sectional area smaller than the portion disposed at the distal end, followed by another bulk reduction actuator. It is also possible to provide an adjacency of. From a hydrodynamic point of view, it is desirable that the proximal portion be given a gradual profile, such as that of a notch or skive, to avoid substantial disturbances of the inflation fluid during the expansion or contraction of the balloon 23.

The transition member 40 preferably provides a smooth transition from the metal adjacent shaft section to the plastic end shaft section. For this reason, the core wire 40 is tapered gradually downward in the terminal direction. In this example, the core wire has an end diameter d1 on the order of 0.31 mm, tapering downwards to an end diameter d2 on the order of 0.13 mm at its distal tip over a length of approximately 279 mm (see FIG. 3). Since this cross-sectional area gradually disappears, the softness of the core wire 40 gradually increases, so that a very smooth transition to the plastic end tubing can be obtained.

As a result, the catheter of the present embodiment can go through the vasculature of patients with very good push ability and steerability while maintaining high progression, without being substantially susceptible to buckling or kink.

Although the invention has been described in more detail in accordance with only a single embodiment, it should be understood that the invention is in no way limited to the above embodiments. On the contrary, many modifications and other embodiments are possible to those skilled in the art without departing from the scope and spirit of the invention. As such, the materials and dimensions used in the preceding embodiments may be replaced with other existing materials and dimensions or newly developed materials and other dimensions to provide the best practical performance. In addition, very good results can be achieved with the core wire of the above example, but other kinds of transition elements may be used.

Claims (9)

A predominantly tubular relatively rigid adjacent shaft section and a shaft attached to the distal end of the adjacent shaft section and including a distal shaft section that is more flexible than the adjacent shaft section, and an inflatable ballon extending from the distal end of the distal shaft section. In a balloon catheter, The adjacent shaft section and the distal shaft section form an expansion lumen extending therein that is in fluid communication with the interior of the balloon to exert an inflation pressure into the balloon, wherein the distal shaft section is a guide for receiving a guide wire. A wire lumen, the guide wire lumen having a guide wire inlet disposed between the end of the adjacent shaft section and the bowl and a guide wire outlet disposed distal to the bolon and directed out of the catheter, the end shaft A flexible transition member is attached to the distal end of the adjacent shaft segment extending into the segment, the distal end of the adjacent shaft section being skived, and the transition member being secured along substantially all of the skived distal ends of the adjacent shaft section. Characterized by a balun Catheter. The method of claim 1, The skived end of the distal shaft section has a predetermined length. The method of claim 1, An adjacent end of the transition member extends inside the tubular portion of the adjacent shaft section, and the adjacent end of the transition member contacts the inner wall of the tubular portion of the adjacent shaft section, while of the transition member disposed at a more distal end. A balloon catheter having a cross section smaller than the portion. The method of claim 3, And said transition member comprises a core wire, said notched end of said core wire being provided with a notch across a side from an inner wall of said tubular portion of said adjacent shaft segment. The method according to any one of claims 1 to 4, At least a distal end of the transition member has a diameter that gradually dissipates in the distal direction. The method of claim 5, And said distal end of said transition member has a predetermined length. The method according to any one of claims 1 to 6, And a distal end of said transition member and said adjacent shaft section are glued together. The method according to any one of claims 1 to 7, The transition member is a balloon catheter, characterized in that having a length of 20 to 30cm. The method according to any one of claims 1 to 8, The transition member is a balloon catheter, characterized in that having a maximum diameter between 0.25 and 0.35mm.