BALLOON CATHETERS

Description

[0001] The invention relates to a balloon catheter for TIPS procedures, comprising a stepped balloon, a lead-in line in the catheter to the balloon which allows the balloon to be pressurized, and a central lumen for a guide wire.

[0002] Balloon catheters have been used for many years to dilate stents in blood vessels. To dilate a stent, it is crimped onto the balloon catheter, which then dilates and positions the stent at the desired implantation site. The balloon catheter is then removed from the vessel without the stent.

[0003] Stents are also used with the help of balloon catheters in connections between two blood vessels (so-called shunts), for example in the liver when creating a TIPS (Transjugular Intrahepatic Portosystemic Shunt) in case of narrowing of the portal vein or high blood pressure in the liver.

[0004] In angioplasty, balloon catheters are used to mechanically widen a narrowed vessel and to press plaques formed there against the vessel wall.

[0005] A particular problem arises when, in the area of ​​vascular bifurcations, both the main branch and the branch itself need to be stented. In this case, a fenestrated stent is first inserted into the main branch and implanted so that the fenestration is located at the bifurcation. Then, another stent is placed into the bifurcation, dilated, and expanded to match the stent in the main branch. This usually requires several separate steps, especially if the branching vessel narrows along its course, necessitating a staged expansion. Furthermore, the stent in the branch must be adapted to the fenestration and the course of the stent in the main branch.

[0006] This adjustment can be achieved by using several balloons of different diameters, inserted sequentially. Alternatively, a so-called "balloon-within-a-balloon" technique is employed, in which two balloons are coupled together so that they can be pressurized separately and used for different expansions. The disadvantage of using multiple separate balloons is the increased effort involved.

[0007] Various catheters with stepped balloons are known from the publications US2014 / 277062A1, US2006 / 265041A1, DE3779539T2, WO97 / 17101A1, US2014 / 276585A1 and US2002 / 120320A1.

[0008] The object of the invention is to provide a balloon catheter with which stents can be precisely placed in branching vessels or shunts and to provide a balloon catheter for TIPS procedures.

[0009] This problem is solved with a balloon catheter according to claim 1, wherein the segments are each individual balloons that are directly adjacent to neighboring individual balloons and that are connected to each other at their end faces via weld points, and wherein the proximal balloon is spherical, wherein the distal balloon has a smaller diameter than the proximal balloon.

[0010] The balloon catheter according to the invention comprises a catheter shaft, a stepped balloon, a lumen for pressurizing the balloon, and a lumen for a guide wire. The balloon itself is stepped, such that at least one region has a larger diameter than another region. In this context, "stepped" means that the individual segments, such as the proximal and distal regions, transition into one another with a step, the step occurring within a relatively narrow range.

[0011] The balloons of the balloon catheters according to the invention have two or more sections with different diameters. For example, the proximal section can have a larger diameter than the distal section, which is advantageous for the placement of stents in side branches of a main vessel.

[0012] Furthermore, balloon catheters according to the invention can also have several stages along their entire length, which is advantageous, for example, in constricting vessels, or a central area with a reduced diameter compared to the proximal and distal areas. The latter variant is suitable, for example, for placing stents in shunts, such as during TIPS placement, where it is important to fit the stent precisely into the shunt without over-expanding it in order to regulate flow.

[0013] The balloon catheter according to the invention can be used both for the dilation of vessels without placing stents and for the placement of stents. For this purpose, the stents are crimped onto the balloon, and they can extend over the entire length of the balloon or only over a portion of it. For example, when placing a stent in a vessel branch, the stent is crimped onto the balloon so that it extends into the area of ​​the step and, as the balloon expands, widens at this end into a trumpet shape, thus conforming to the wall of the main vessel or to a stent placed within a main vessel.

[0014] The balloon sections of the balloon catheter according to the invention represent individual segments corresponding to the stages. These segments can be connected to each other or separated from each other by walls.

[0015] The balloon, for example, has an expanded proximal and a reduced distal section. The distal section is kept relatively slender. It may have a uniform diameter along its length, but it can also taper further towards the distal end of the catheter to accommodate narrowing side branches.

[0016] The proximal region of the balloon in the balloon catheter according to the invention has a significantly larger diameter compared to the proximal region. In particular, the diameter is increased by approximately 50 to 100%.

[0017] Between the proximal and distal sections of the balloon, there may be a middle section with a diameter intermediate between that of the proximal and distal sections. In this case, the balloon has a three-stage design. A four-stage design is also possible, with the diameters of the individual segments decreasing from proximal to distal.

[0018] In this variant, the balloon typically has a diameter (in expanded state) of 5 to 14 mm in the proximal area and 2 to 6 mm in the distal area.

[0019] If the balloon has a proximally expanded area, its flanks exhibit a relatively steep slope, preferably uniform on both sides—that is, the slope from the catheter shaft on one side and the slope from the proximal part of the balloon on the other. Advantageously, the slope is 45 to 75° (not specified), relative to the catheter axis. A steep slope of the expanded zone is beneficial for the trumpet-shaped expansion of the stent at the branch inlet and for its adaptation to the stent placed in the main branch or to the main vessel from which the branch originates.

[0020] The balloon of the balloon catheter according to the invention can thus be divided into several segments, each segment having a separate supply line for pressurization. The individual segments are each individual balloons that directly adjoin neighboring individual balloons. In this case, the individual balloons are expediently connected to one another.

[0021] The individual segments expediently correspond to the aforementioned proximal, distal, and, if applicable, middle regions, i.e., the individual steps. If individual balloons are used, they are glued together at the points of contact, i.e., where the steps are located, or spot-welded together according to the invention. The connection of the individual balloons is important for uniform expansion.

[0022] When using the balloon catheter according to the invention, which is divided into several segments or individual balloons and has an expanded proximal region, the distal region is dilated first for stent placement, followed by the middle region, if present, and finally the proximal region, which requires the greatest dilation and where the stent must be adapted to the fenestration of the stent in the main branch or to the shape of the bifurcation in the branching region. If it is a simple balloon without division into individually dilatable segments, the dilation occurs uniformly over the entire length.

[0023] In principle, it is possible to surround the balloon catheter with an outer balloon that fits snugly against the underlying inner balloon or balloons. In one variant, the outer balloon serves a safety function; that is, it is not dilated separately but expands along with the expansion of the underlying balloon or its segments or balloons. Alternatively, it is possible to also dilate the outer balloon to create a pre-expansion and then achieve final expansion via the inner balloon. In either case, the contours of the outer balloon and the inner balloon or balloon segments or balloons are precisely matched.

[0024] The balloon catheter according to the invention is manufactured in the usual manner. The materials used are also standard materials for this field. The only difference from the prior art lies in the design of the balloons.

[0025] Conventional materials can be used for the balloons. Preferably, a non-compliant material with limited elasticity, such as polyamide 12, PET, or nylon, is used for the inner balloon, and a compliant or semi-compliant material, such as silicone rubber, Pebax, PA 11, or a mixture of Pebax and PA 11, is used for the outer balloon.

[0026] The invention is explained in more detail by the accompanying drawings. They show: Fig. 1: An overall view of a balloon catheter; Fig. 2: A sectional drawing through the balloon catheter of Figure 1 ; Fig. 3: a second variant of a balloon catheter in section; and Fig. 4: a sectional drawing of a double balloon for TIPS procedures.

[0027] Figure 1Figure 1 shows a balloon catheter 1 with a significantly enlarged proximal region P with steep flanks 7 towards the catheter and 6 towards the distal region D, and a relatively slender distal region D that tapers distally to the catheter diameter. The catheter 2 passes through the balloon construct 4 and terminates distal to the balloon construct 4.

[0028] For use, a stent is crimped onto the balloon catheter, which is expanded by the inflation of the balloons and placed in a blood vessel. The illustration shows catheter 1 with an expanded balloon.

[0029] Figure 2 shows a cross-sectional drawing through the balloon catheter 1 according to Figure 1 with the catheter 2, a free lumen 3 for a guide wire for placing the catheter and the balloon 4.

[0030] Balloon 4 is differentiated into the proximal region P, the distal region D, the middle region M and the terminal region T.

[0031] The proximal region P is significantly wider than the distal region D. The middle region M is smaller in diameter than the proximal region P, but has a larger diameter than the distal region D. The transitions from the proximal region P to the middle region M and from the middle region M to the distal region D, as well as in the terminal region T, are formed by relatively steep flanks 6, 8, and 9. Flank 6 is crucial for the adaptation of a stent to the fenestration of a stent in the main branch, or for the adaptation to the vessel wall in the main branch during stent placement.

[0032] In the terminal region T, the balloon narrows and seals tightly before the end of the catheter 2. The channels used to fill the balloons with fluid are conventional and are not shown in the drawing.

[0033] Figure 3Figure 1 shows a variant of the double balloon in which balloon 4 is surrounded by an outer balloon 5. The outer balloon 5 provides greater safety and, if a separate expansion via another lumen is present, allows for more precise and targeted dilation and adaptation of the stent to the vessel's course. Otherwise, balloon 1 corresponds to... Figure 3 the representation in Figure 2 .

[0034] Figure 4Figure 1 shows a balloon catheter 1 according to the invention for TIPS procedures, comprising a proximal balloon 11 with an expanded diameter and a distal balloon 10 with a smaller diameter. Both balloons are separately expandable, as required for TIPS procedures in the liver. The two balloons are connected to each other via adhesive or weld points 12, so that they form a unit when expanded. The lumens for the separate inflation of the balloons are not shown. The lumen 3 for a guide wire for positioning the device 1 is shown.

[0035] It is understood that there are numerous variations in the design of the proximal and distal regions. According to the invention, the proximal region is spherical. The distal region is shown with the same diameter (not claimed), however, it is readily possible to provide a further step or tapering towards the terminal end of the catheter. For example, the distal region can have a 40% reduction in diameter along its length towards the terminal end, whereby this tapering can be continuous or stepwise.

Claims

1. Stepped balloon catheter for TIPS procedures, being provided with a balloon (4), supply lines in the catheter leading to the balloon (4), which allow the balloon (4) to be pressurized, and a central lumen (3) for a guidewire, wherein the balloon (4) is subdivided into several segments, and each segment having a separate supply line for pressurization purposes and wherein the balloon in its expanded state comprises at least two areas (P, D) of different diameter, with these areas (P, D) merging into one another by forming a step, characterized in that each of the segments are single balloons that are directly adjacent to neighboring single balloons and are connected to each other via weld spots at their end faces, and in that the proximal balloon has a spherical-like shape, wherein the distal balloon has a smaller diameter than the proximal balloon.

2. Balloon catheter according to claim 1, characterized in that the proximal area (P) of the balloon (4) has an enlarged diameter by 50% to 100% relative to the distal region (D).

3. Balloon catheter according to claim 1 or 2, characterized in that the enlarged area has steeply rising flanks (6, 7).

4. Balloon catheter according to any one of the preceding claims, characterized in that the balloon (4) is surrounded by an external balloon (5).

5. Balloon catheter according to any one of the preceding claims, characterized in that a stent is crimped on the balloon.