Balloon catheter for delivering branching stents to branching vessels

Abstract

The present invention relates to a balloon catheter for delivering a branching stent to a branching vessel. The balloon catheter includes a hub, a shaft, a single balloon connected to the shaft, and an inflation port of the hub that is in fluid communication with the single balloon, the single balloon including a first distal portion, a second central portion, and a third proximal portion, the delivery configuration being such that the first distal portion of the balloon and the third proximal portion of the balloon are adjacent to each other by bending the first distal portion of the balloon to the third proximal portion of the balloon.

Description

Technical Field

[0001] The present invention relates to medical devices and methods for treating lesions of branched blood vessels. The present invention further relates to a system for treating aortoiliac occlusive disease (AIOD) with a retrograde approach.

Background Art

[0002] Aortoiliac occlusive disease (AIOD) is a stenosis or occlusion of a blood vessel including the portion where the abdominal aorta transitions to two iliac arteries. This stenosis or occlusion is typically caused by the accumulation of plaque in the aorta, aortic bifurcation, and iliac arteries. As a result of the plaque, the diameter of the blood flow lumen in the iliac artery decreases, thereby restricting blood flow to the patient's legs and organs within the pelvis.

[0003] Endovascular procedures for the treatment of AIOD typically involve placing a bare or covered stent within the bifurcation. The stent may be self-expanding or balloon-expandable. Generally, two treatment types are used to treat AIOD including the aortic bifurcation. These include the kissing stent and covered endovascular reconstruction of the aortic bifurcation (CERAB). The kissing stent is a technique in which two stents are placed at the aortic bifurcation and cross each other over the aortic bifurcation. Similarly, covered endovascular reconstruction is a technique in which the main stent graft body is implanted in the aorta over the aortic bifurcation, and separate stent graft branches for each iliac artery are implanted so as to cross each other within the main stent graft body over the aortic bifurcation.

[0004] Both techniques involve the simultaneous placement of two parallel or "kissing" stents across the bifurcation, as well as the placement of a stent or stent graft in the aorta.

[0005] A common drawback of these two techniques is the disruption of natural blood flow through the bifurcation, which can lead to thrombosis, hemolysis, embolism, and restenosis. Another drawback is the need for precise simultaneous placement of two kissing stents and the advanced technical skill set required to perform this procedure. Furthermore, two kissing stents make re-intervention using a retrograde approach (up-and-over technique) extremely difficult. Yet another drawback is that when using a conventional balloon to expand or re-expand a primary stent in the aorta, the balloon bulge, which is inevitably relatively long for a balloon of a suitable diameter for the aorta, forces physicians to maintain a certain distance from the bifurcation to avoid the risk of over-expanding the vessel in this region, thus preventing stent placement in close proximity to the bifurcation. Because the balloon bulge is symmetrical at both ends, this drawback exists in both retrograde and antegrade approaches. Here, the retrograde approach is widely preferred due to fewer complications during the procedure.

[0006] There is a clear need for medical devices and methods for treating AIOD, including the aortoiliac bifurcation, that overcome the aforementioned shortcomings of existing methods. These shortcomings are addressed by the medical devices and methods for treating bifurcation vessels, including the aortoiliac bifurcation, described herein. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2011 / 257722 [Patent Document 2] International Publication No. 2022 / 060994 [Patent Document 3] U.S. Patent Application Publication No. 2023 / 144448 [Patent Document 4] U.S. Patent Application Publication No. 2020 / 030128 [Overview of the Initiative]

[0008] Generally described herein are medical devices and methods for the treatment of any disease involving a bifurcation within a body cavity. In some embodiments, the devices and methods are intended for the treatment of aortoiliac artery occlusion (AIOD). The devices and methods described herein may also be used for the treatment of any other disease in the body involving an aortic aneurysm or a bifurcation within a body cavity.

[0009] For consistency, when describing this device, the direction toward the external end of the catheter outside the body is called the "proximal," and the direction away from the external end of the catheter is called the "distal." The side on which the catheter is inserted into a peripheral artery is called the "ipsilateral," and the opposite side is called the "contralateral." For example, if the catheter is inserted into an artery in the right leg, the right side of the body is called the ipsilateral, and the right iliac artery is called the ipsilateral iliac artery. The left side is called the contralateral, and the left iliac artery is called the contralateral iliac artery.

[0010] In some embodiments, the branching stent includes a main body stent, a first branching stent, and a second branching stent. In other embodiments, the branching stent includes a main body stent and one branching stent. In some embodiments, the branching stent may include two or more branching stents. In some embodiments, the branching stent includes a main body and two non-tubular stent extensions for reaching side branches of a blood vessel.

[0011] The branched stent may be a bare-metal stent. In other embodiments, the branched stent may be a coated stent. In other embodiments, the stent may be a covered stent. This is also called a stent graft or endoprosthesis. In further embodiments, the branched stent may be any combination of a bare stent and / or a coated stent and / or a covered stent. In alternative embodiments, the stent may be made from a polymer material or may be biodegradable.

[0012] The stent may be covered with a layer of polymer or animal tissue. The cover may be made of woven or knitted fibers, polymers, porous materials, or non-porous materials. The cover material may be made of polyurethane, PET (polyethylene terephthalate), non-expanded PTFE (polytetrafluoroethylene), expanded ePTFE, or ultra-high density polyethylene (UHDPE). The cover can be attached to the stent by any suitable means known in the art, such as fibers, sutures, or adhesives, or by clamping the cover between stent struts, sintering, bonding, fusing, joining, or encapsulating the stent with a membrane.

[0013] Stents can be made of metal, metal alloys, polymers, and / or combinations thereof. Stent covers may be made of polymer or mammalian tissue. Branched stents may include a series of stent rings connected via multiple longitudinal struts or a single cover.

[0014] In some embodiments, the stent can be laser-cut from a metal tube or a polymer tube. In other embodiments, the stent may be formed from a metal wire or a polymer wire. In some embodiments, the main body stent and the two branch stents may be welded together or connected by another mechanism such as, but not limited to, sutures, adhesives, connectors, joints, and / or a combination thereof. In some embodiments, the main body stent and the two branch stents are connected by a material different from the material used to construct the stent.

[0015] A branched stent may include a series of individual stent rings connected by a cover. A branched stent may include at least two overlapping stents, where the proximal segment of each stent forms its respective branch, and the distal segment of each stent forms the main body. In some embodiments, the branched stent includes two or more overlapping stents. In some embodiments, the main body stent and the two branched stents are formed integrally; that is, the branched stent is manufactured as a single unit. In other embodiments, the branched stent is formed from three individual stents joined together by welding.

[0016] A catheter for delivering a branched stent includes a catheter shaft and a single balloon attached to the distal portion of the catheter shaft. In other embodiments, the catheter includes a catheter shaft and two balloons, a first single balloon attached to the distal portion of the catheter shaft and a second balloon attached to the catheter shaft proximal to the first balloon.

[0017] The catheter shaft includes an inflatable lumen that is in fluid communication with a hub at the proximal end of the shaft (outside the patient's body) and with a single balloon.

[0018] In another embodiment in which the catheter includes two balloons, the catheter includes two inflatable lumens. The first inflatable lumen is in fluid communication with a first hub at the proximal end of the shaft and with the first balloon, and the second inflatable lumen is in fluid communication with a second hub at the proximal end of the shaft and with the second balloon. This allows the two balloons to be inflated separately.

[0019] The catheter shaft further includes a guidewire lumen, which connects a first opening in the catheter shaft at the distal end of the catheter to a second opening at the proximal end of the catheter. The guidewire lumen houses a pre-loaded guidewire. The catheter may be in an over-the-wire configuration or may be constructed as a rapid-exchange catheter. In another embodiment, the catheter shaft includes a fixed guidewire. When a fixed guidewire is used, the catheter does not necessarily require a guidewire lumen. Instead or additionally, the guidewire may be integrated into the shaft or, in another embodiment, directly attached to the shaft.

[0020] A single balloon may have any shape. In some embodiments, the balloon may be cylindrical. In other embodiments, the balloon has a first distal portion, a second central portion, and a third proximal portion. The balloon portions are arranged in a line on the catheter shaft so that a single balloon can take a linear configuration. Each portion may have any shape. Each portion may have the same shape as the other two portions, each portion may have an individual shape, or the first and third portions may have the same shape and the second portion may have a different shape. In a preferred embodiment, the balloon includes at least a first waist portion between the first distal portion and the second central portion, and at least a second waist portion between the second central portion and the third proximal balloon portion. In the context of this application, a waist portion is defined as a region of the balloon at both ends of the waist portion with a reduced outer diameter compared to the adjacent balloon portions. The reduction in diameter of the waist portion is at least 50% compared to the adjacent balloon portions. It is explicitly stated that the balloon wall is not attached to the catheter shaft in the region of the waist portion. This means that the balloon has one single lumen and one single inflatable or deflated lumen, i.e., the balloon segments share one single lumen, i.e., the balloon lumen.

[0021] In some embodiments, the individual balloon portions may be of a rotationally symmetric shape, cylindrical, conical, or spherical, or concave or convex, or stepped, or any combination thereof. When an individual balloon portion is stepped, the balloon diameter of the larger balloon portion increases by up to 50% compared to the diameter of the smaller balloon portion along the step. In one embodiment, the proximal portion of the third proximal balloon portion has a diameter that is up to 50% greater than the distal portion of the third proximal balloon portion. In another embodiment, the distal portion of the first distal balloon portion has a diameter that is up to 50% greater than the proximal portion of the first distal balloon portion. In another embodiment. In another embodiment, both the distal portion of the first distal balloon portion and the proximal portion of the third proximal balloon portion have a diameter that is up to 50% greater than the proximal portion of the first distal balloon portion and / or the distal portion of the third proximal balloon portion.

[0022] In some embodiments, the central balloon portion may be spherical. In further embodiments, the central portion itself includes one or more additional waist portions, i.e., portions where the outer diameter is reduced compared to adjacent balloon portions.

[0023] A single balloon may have a first distal portion including at least a first diameter, a second central portion including at least one second diameter, and a third distal segment including a third diameter. In some embodiments, the first diameter is smaller than the second diameter. In other embodiments, the third diameter is smaller than the second diameter. In some embodiments, the first diameter and the third diameter are the same. In some embodiments, the first, second, and third diameters are the same. In further embodiments, each balloon portion may be of an individual shape such as, but not limited to, a rotationally symmetric shape, cylindrical, conical, or spherical, or concave or convex, or stepped, or any combination thereof.

[0024] The catheter can transition from a delivery configuration to a retracted configuration.

[0025] In that delivery configuration, the first distal portion of the single balloon is bent to the third proximal portion of the balloon, whereby the first distal portion and the second proximal portion of the balloon are arranged adjacent to each other. In one embodiment, the first distal portion and the second proximal portion of the balloon are arranged substantially parallel to each other. In one embodiment, the first distal portion and the second proximal portion of the balloon are arranged parallel to each other. In one embodiment, the proximal portion of the distal portion of the balloon and the distal portion of the proximal portion of the balloon are arranged in a configuration parallel to each other. That is, the first distal portion and the third proximal portion of the balloon are arranged in a configuration at least partially parallel to each other. In the delivery configuration of the catheter in which the first distal portion of the balloon is bent to the third proximal portion of the balloon, the central portion of the balloon functions as the bending position of the balloon. The central portion of the balloon allows the balloon to bend 180° without kinking or blocking the balloon lumen.

[0026] The branched stent may be attached to a catheter including a balloon having three balloon portions by attaching the first branched stent of the branched stent to the first balloon portion, attaching the second branched stent of the branched stent to the third balloon portion, and attaching the main body of the branched stent to the first balloon portion and the third balloon portion. The second central portion of the balloon does not carry any stent. The central portion functions as the bending position of the balloon.

[0027] In its retracted configuration, the first distal portion, the second central portion, and the third proximal portion of the single balloon of the catheter are arranged in a linear configuration along the catheter shaft, i.e., the first distal balloon portion is not bent to the third proximal balloon.

[0028] Thus, the catheter can transition from its delivery configuration, which is a bent configuration, to its retracted configuration, which is a linear configuration of the single balloon of the catheter.

[0029] Multiple methods for stent placement at the aortic-iliac artery bifurcation are also described herein. These methods can utilize the stents, bifurcation stents, and catheters described herein.

[0030] In some embodiments, a method for placing a stent in a blood vessel in direct proximity to a bifurcation of a patient's blood vessel includes: a) attaching a main body stent to a catheter having a single balloon having a first distal portion, a second central portion, and a third proximal portion, wherein the main body stent is pressed against the proximal portion of the first distal portion and the distal portion of the third proximal balloon portion, and the first balloon portion is bent to lie on the third balloon portion; b) advancing the catheter with the stent attached to the balloon through the bifurcation from the ipsilateral vessel; c) placing the stent in the patient's main vessel in direct proximity to the bifurcation of the vessel into the branching vessel by partially retracting the catheter; d) expanding the main body stent in the main vessel by inflating the single balloon; e) deflating the balloon; f) retracting the catheter through the ipsilateral vessel; and g) removing the catheter from the patient.

[0031] In one embodiment, a method for treating a lesion in a branch vessel including a main vessel and two branch vessels includes: a) attaching the first branch of a branch stent to the first balloon portion, attaching the second branch of the branch stent to the third balloon portion, and attaching the main body of the branch stent to both the first and third balloon portions of a balloon catheter; b) advancing the catheter with the stent attached to the balloon portion through the branch from the ipsilateral vessel; c) placing the branch stent at the branch so that the main body is in direct proximity to the branch by partially retracting the catheter; d) expanding the branch stent at the branch by inflating a single balloon; e) deflating the balloon; f) retracting the catheter through the ipsilateral vessel; and g) removing the catheter from the patient.

[0032] In some embodiments, a snare may be advanced from the opposite side to capture the guidewire, facilitating the placement of a second stent in the contralateral vessel, or facilitating the placement of a primary stent in direct proximity to the bifurcation.

[0033] If necessary, post-dilation of the branch stents can be performed to fit the main stent and at least two branch stents to the vessel wall of the main vessel and to each of its branches. The same or similar steps can be used to treat various different branches within the body.

[0034] Furthermore, in certain embodiments, it may be desirable to insert the sheath from the opposite side adjacent to the bifurcation to enable protected placement of the stent graft. Therefore, in further embodiments of the present invention, a catheter equipped with an aligner at the distal end is provided to ensure proper alignment of the tip of the sheath with the opposite portion of the stent graft attached to the balloon, thereby preventing damage to the stent graft. Such an aligner may be a bumper located distal to the distal balloon end, or a bumper located within the distal end of the balloon, or a skirt attached to the catheter at its distal tip and covering the distal portion of the catheter including the distal portion of the opposite portion of the stent graft. Alternatively, the aligner may be an expandable cage provided with a guidewire and positioned adjacent to the distal end of the catheter. [Brief explanation of the drawing]

[0035] [Figure 1A-1B] Figures 1A and 1B show conventional stent placement in the main vessel at a bifurcation. [Figure 2] This invention demonstrates the delivery configuration of a catheter device. [Figure 3] This invention shows the retracted configuration of the catheter device. [Figure 4] Another embodiment of the catheter device described herein is shown. [Figure 5A-5B] Figures 5A and 5B show a medical device according to the present invention. [Figure 6A-6C] Figures 6A to 6C show another embodiment of the medical device according to the present invention. [Figures 7A-7D] Figures 7A to 7D show the medical devices described herein. [Figures 8A-8D] Figures 8A to 8D show another embodiment of the medical device described herein. [Figures 9A-9C] Figures 9A to 9C illustrate another embodiment of the medical device described herein. [Figure 10A-10C] Figures 10A to 10C illustrate another embodiment of the medical device described herein. [Figure 11A-11C] Figures 11A to 11C illustrate another embodiment of the medical device described herein. [Figure 12] This shows various embodiments of catheter devices, including aligners. [Figure 13] This shows various embodiments of catheter devices, including aligners. [Figure 14] This shows various embodiments of catheter devices, including aligners. [Figure 15] This illustrates various embodiments of catheter devices, including aligners. [Figure 16] This illustrates various embodiments of catheter devices, including aligners. [Modes for carrying out the invention]

[0036] Herein, preferred current embodiments of the present invention will be described in detail, with examples shown in the accompanying drawings. The methods and corresponding steps of the present invention will be described in conjunction with a detailed description of the intravascular stent delivery catheter device.

[0037] When treating aortic-iliac artery occlusion (AIOD) using conventional methods such as the CERAB technique, it is necessary to place a single stent or stent graft in the aorta. To optimize the outcome of the stent placement procedure, it is highly beneficial to place this primary stent as close as possible to the bifurcation site. Firstly, such close placement ensures good patency of the narrowed aorta, and secondly, close placement of the aortic stent at the bifurcation site ensures that the new branch created by the stent placement is as close as possible to the original vascular anatomy. However, the balloons 10 of conventional delivery catheters have relatively large balloon bulges, mainly due to the relatively large size of these balloons. As seen in Figure 1A, due to the balloon bulge, there is a high risk of hyperdilation of the side branch vessels if the stent 60 is too close to the bifurcation. On the other hand, if it is confirmed that the balloon bulge does not hyperdilate the side branch, the distance between the proximal stent end 60b and the bifurcation is too far, making smooth stent placement at the bifurcation unacceptable (see Figure 1B). This issue with the current procedure is independent of whether the treatment is performed retrogradely ("from below") or antegradely ("from above"). This is because the balloon protrusion at the distal end of the stent is similar to the balloon protrusion at the proximal end of the balloon. Due to fewer side effects, physicians generally prefer the retrograde approach.

[0038] According to the present invention, a catheter device is provided that overcomes the above-mentioned problems and enables precise stent placement in branched vessels using a retrograde approach.

[0039] Figure 2 shows the delivery configuration of a catheter device according to the present invention. The balloon catheter 1 for delivering a branch stent to a branch vessel includes a hub 20, a shaft 2, a single balloon 10 connected to the shaft at the distal portion of the shaft, and an inflation port 21 of the hub that is in fluid communication with the balloon. The shaft further has a guidewire lumen 22 that houses a pre-loaded guidewire 80 and extends through the hub, shaft, and balloon. The balloon includes a first distal portion 11, a second central portion 12 or also called a second intermediate portion, and a third proximal portion 13. Here, in the delivery configuration, the first distal portion 11 of the balloon is bent to the third proximal portion 13 of the balloon, so that the first distal portion and the third proximal portion of the balloon are adjacent to each other. Figure 2 shows that the first distal portion 11 and the third proximal portion 13 of the balloon are arranged in a parallel configuration. However, those skilled in the art will readily understand that the first and third balloons may be arranged partially parallel to each other. Here, the distal portion of the third proximal portion and the proximal portion of the first distal portion are arranged adjacent to each other and parallel to one another, while the distal portion of the first distal portion of the balloon and the proximal portion of the third proximal portion of the balloon are arranged at an angle to each other.

[0040] As shown in Figure 2, in the catheter delivery configuration, when the first distal portion 11 of the balloon is bent or folded up to the third proximal portion 13 of the balloon, the second central portion 12 of the balloon functions as the bending point of the balloon. The central or intermediate portion of the balloon allows the balloon to bend 180° without kinking or blocking the guidewire lumen, and without blocking the balloon lumen.

[0041] In general, various inflatable balloon catheters are known and suitable for the stent delivery system of the present invention. Elongated catheters have sizes and configurations for delivery through tortuous anatomical structures. For illustrative purposes only, the catheter shaft 2 embodied herein includes an outer tubular member 24 and an inner tubular member 25. As shown in Figure 2, the inner tubular member 25 defines a guidewire lumen 22 for a pre-loaded guidewire 80. Figure 2 shows the guidewire lumen 22 in an over-the-wire (OTW) configuration, although the guidewire lumen 22 can be configured for rapid exchange (RX) delivery, as is well known in the art. Alternatively, the catheter body may include a fixed guidewire to allow the catheter to be delivered to a vascular location without the use of another guidewire. The fixed guidewire extends beyond the distal end of the balloon. Optionally, the distal end of the guidewire may be formed as a hook.

[0042] An inflatable lumen 30 is defined between the outer tubular member 24 and the inner tubular member 25, extending between the proximal and distal ends of the catheter shaft 2. Specifically, as shown in Figure 2, the coaxial relationship between the inner tubular member 25 and the outer tubular member 24 defines an annular inflatable lumen 30 between them. The balloon 10 is provided to be in fluid communication with the inflatable lumen 30. The inflatable lumen 30 can supply pressurized fluid to expand the balloon 10 to its deployed state and, if desired, can establish negative pressure to deflate the balloon 10. Thus, the inflatable balloon 10 can be inflated and deflated using the inflatable lumen 30. Suitable materials and techniques are well known for constructing the catheter shaft.

[0043] As shown in Figure 2, the single balloon 10 of the balloon catheter of the present invention may include at least a first waist portion 101 between the first distal portion 11 and the second central portion 12, and at least a second waist portion 102 between the second central portion 12 and the third proximal balloon portion 13.

[0044] The waist portion is defined as the region of the balloon whose outer diameter is reduced compared to the adjacent balloon portion. In one embodiment, the waist portion has a diameter that is reduced by at least 50% compared to the adjacent balloon portion. The length of the waist portion is short, and as a result, the waist portion constitutes a contraction or local stenosis. In one embodiment, the length of the waist is up to 4 mm, preferably up to 2 mm, preferably up to 1 mm. It is explicitly stated that the balloon wall is not attached to the catheter shaft in the region of the waist portion. This means that the balloon has one single lumen and one single inflatable or deflated lumen, i.e., the balloon segments share one single lumen i.e., the balloon lumen. The purpose of the waist portions 101, 102 is to increase the bending flexibility of the balloon during inflation. The central portion of the balloon allows the balloon to bend 180° without kinking or blocking the balloon lumen. Also, by the central portion of the balloon acting as a bending element, the balloon according to the present invention maintains its bent delivery configuration during inflation. Even high pressure in the balloon lumen does not force the balloon to bend back to its retracted configuration or force a reduction in the angle at which the first balloon portion bends to the third balloon portion. Furthermore, the second balloon portion or bending element of the balloon catheter provides high torque to the catheter, thereby facilitating the physician to rotate the catheter within the body's blood vessels and correctly position the distal portion of the balloon in the contralateral branch.

[0045] Figure 2 shows the balloon catheter of the present invention in a bent configuration. The bent configuration is intended to deliver the balloon to the treatment site, as well as to allow the balloon to be inflated for the treatment of lesions in branched vessels. Figure 3 shows one embodiment of the balloon catheter 1 in its deflated configuration. Here, to illustrate the construction principle, the single balloon 10 is shown to be substantially straight. The balloon catheter takes this configuration when it is removed from the branched vessel during deflation.

[0046] As can be seen in more detail in Figure 3, in one embodiment of the present application, the balloon catheter includes a catheter shaft 2 and a single balloon 10 connected to the shaft at the distal portion of the catheter. The catheter shaft 2 includes an outer tubular member 24 and an inner tubular member 25. The inner tubular member 25 defines a guidewire lumen 22 for a guidewire (not shown). An inflatable lumen 30 extends between the outer tubular member 24 and the inner tubular member 25, between the proximal and distal portions of the catheter shaft 2. The distal end of balloon 16 is liquid-tightly attached to the distal end of the inner tubular member 25 to form the catheter tip 40. The proximal end of balloon 17 is liquid-tightly attached to the distal end of the outer tubular member 24.

[0047] As shown in Figures 2 and 3, the coaxial relationship between the inner tubular member 25 and the outer tubular member 24 defines an annular inflatable lumen 30 between them. Therefore, the balloon 10 is provided to be in fluid communication with the inflatable lumen 30. The balloon 10 of the balloon catheter shown in Figure 3 includes a first waist portion 101 between the first distal balloon portion 11 and the second central balloon portion 12, and a second waist portion 102 between the second central balloon portion 12 and the third proximal balloon portion 13.

[0048] Figure 3 shows the retracted configuration of the catheter device according to the present invention. In this linear retracted configuration, the first distal portion 11, the second central portion 12, and the third proximal portion 13 of the single balloon 10 of the catheter 1 are arranged in a linear configuration along the catheter shaft 2.

[0049] As shown in Figure 3, the waist portions 101 and 102 are regions where the balloon diameter is reduced. The diameter reduction is at least 50%. The balloon is attached to the catheter shaft only at its distal 16 and proximal 17 ends. The balloon's waist portion is not attached to the catheter shaft (or the inner or outer tubular member).

[0050] In this configuration, the second central portion 12 of the balloon is bordered by at least one waist portion 101 distal to the second central balloon portion and at least one waist portion 102 proximal to the second central balloon portion, which allows the balloon to be bent or folded 180° in its central portion without stretching the balloon or deflating the inflated lumen. Thus, a single balloon can be easily and quickly inflated and deflated.

[0051] As described above, individual balloon sections may have a rotationally symmetrical shape, cylindrical shape, conical shape, stepped shape, or tapered shape. For the central balloon section 12, a spherical shape is preferred. In some further embodiments, the central balloon section 12 may include one or more additional waist sections, i.e., sections with a reduced outer diameter compared to adjacent balloon sections. As shown as an example in Figure 3, the central balloon section may consist of a series of short balloon sections interrupted by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more additional waist sections, but is not limited thereto. The short balloon sections may be spherical or take other suitable shapes that allow for non-contracting bending or folding of the balloon.

[0052] During the placement of branch stents in branch vessels, regardless of the system or technique applied, the proximal portion of the main stent or aortic stent is often retrogradely expanded using a balloon with a larger diameter. This is done to improve contact between the main stent portion and the vessel wall to ensure smooth transition and avoid turbulence, blood coagulation, and restenosis in this region. This procedure requires an additional balloon.

[0053] To address this need, further embodiments of the present invention include a balloon catheter according to the present invention, as described in detail above, the balloon catheter further includes a second additional balloon positioned proximal to the first balloon and attached to the catheter shaft. The second balloon is in fluid communication with a second inflation lumen and a second inflation port of a hub at the proximal end of the shaft.

[0054] In one embodiment shown in Figure 4, a balloon catheter 1 for delivering a stent to a branched vessel includes a proximal hub 20, a shaft 2, a single balloon 10 connected to the shaft at the distal portion of the shaft, and a first inflation port 21 of the hub that is in fluid communication with the balloon. The shaft further houses a pre-loaded guidewire 80 and has a guidewire lumen 22 extending through the hub, shaft, and balloons 10, 210. The single balloon includes a first distal balloon portion 11, a second central balloon portion 12, and a third proximal balloon portion 13. Here, in the delivery configuration, the first distal portion 11 of the balloon is bent to the third proximal portion 13 of the balloon 10, so that the first distal portion and the third proximal portion of the balloon are adjacent to each other (Figure 4 shows a catheter in an unbent configuration). The catheter further includes one additional balloon 210 positioned proximal to the first single balloon 10 and attached to the catheter shaft. The second balloon 210 is in fluid communication with the second expansion lumen 230 and the second expansion port 221 at the hub of the proximal end of the shaft.

[0055] The second balloon 210 has an outer diameter larger than the maximum diameter of the single balloon 10. In another embodiment, the outer diameter of the second additional balloon is equal to or greater than the outer diameters of the first distal portion and the third proximal portion of the balloon in the bent configuration.

[0056] As described above, several methods for placing stents or stent grafts at the aortoiliac artery bifurcation are also described herein. These methods can utilize the stents, stent grafts, bifurcation stents or bifurcation stent grafts and catheters described herein.

[0057] In some embodiments, a method for placing a stent or stent graft in a blood vessel in direct proximity to a bifurcation of a patient's blood vessel includes: a) attaching a main body stent to a catheter having a single balloon having a first distal portion, a second central portion, and a third proximal portion, wherein the main body stent is pressed against the proximal portion of the first distal portion and the distal portion of the third proximal balloon portion, and the first balloon portion is bent to lie on the third balloon portion; b) advancing the catheter with the stent or stent graft attached to the balloon retrogradely through the bifurcation; c) placing the stent in the patient's main vessel in direct proximity to the bifurcation of the blood vessel into the branching vessel by partially retracting the catheter; d) expanding the main body stent in the main vessel by inflating the single balloon; e) deflating the balloon; f) retracting the catheter; and g) removing the catheter from the patient.

[0058] In one embodiment, a method for treating a lesion in a branch vessel including a main vessel and two branch vessels includes: a) attaching a first branch of a branch stent or stent graft to a first balloon portion, attaching a second branch of the branch stent to a third balloon portion, and attaching the main body of the branch stent to both the first and third balloon portions of a balloon catheter; b) advancing the catheter with the stent attached to the balloon portion retrogradely from the ipsilateral vessel through the branch; c) placing the branch stent or stent graft in the branch such that the main body is in direct proximity to the branch, with the catheter partially retracted so that the first branch is located in the ipsilateral vessel and the second branch is located in the contralateral vessel; d) expanding the branch stent or stent graft in the branch by inflating a single balloon; e) deflating the balloon; f) retracting the catheter through the ipsilateral vessel; and g) removing the catheter from the patient.

[0059] In some embodiments, a snare may be advanced from the contralateral side to capture the guidewire of the balloon catheter, facilitating the placement of a second branch into the contralateral vessel, or facilitating the placement of the main body of a branch stent in direct proximity to the bifurcation.

[0060] Furthermore, in certain embodiments, such as when the contralateral vessel contains a narrow lesion, but not limited thereto, it may be preferable to introduce the sheath into the contralateral vessel before deploying the stent or stent graft, thereby enabling protected delivery of the stent or stent graft by the contralateral sheath.

[0061] Here, we refer to Figures 5A and 5B, which show a medical device according to an embodiment of the present application. The medical device includes a catheter and a stent mounted thereon according to the present invention.

[0062] Figure 5A shows a medical device system for treating lesions in branched vessels, the system comprising a main body 65 and a stent 60 comprising the catheter of the present invention for delivering the stent in a branched vessel.

[0063] The catheter includes a single balloon having a first distal portion 11, a central portion 12, and a third proximal portion 13. Here, the main body of the stent 65 is crimped onto both the proximal portion of the first distal portion and the distal portion of the third balloon portion. Here, the first balloon portion 11 is bent and rests on the third balloon portion 13. Thus, the first distal balloon portion and the third proximal balloon portion are positioned side by side, and the main body of the stent is crimped onto both the first and third balloon portions.

[0064] As shown in Figure 5B, the medical device in Figure 5A is shown to be placed and expanded near the bifurcation of a branched vessel. Using a folded or bent balloon in a retrograde delivery approach allows for the proper placement of the main stent portion within the main vessel near the bifurcation without the risk of over-dilation of the branch. Therefore, the balloon catheter of the present invention enables accurate, precise, and non-damaging delivery of a stent to a main artery adjacent to a branch of a branched vessel.

[0065] In another preferred embodiment of the present invention, the stent 60 is a branch stent comprising a main body stent 65, a first branch stent 63, and a second branch stent 61, which is attached to the balloon catheter of the present invention for delivery to a branch vessel. Figure 6A shows a medical device for treating a lesion in a branch vessel. The system comprises a branch stent comprising a main body stent portion, a first branch stent portion 63, and a second branch stent portion 61, and a catheter for delivering the branch stent to a branch vessel, the catheter comprising a single balloon having a first distal portion, a second central portion, and a third proximal portion. Here, the first branch stent 63 is crimped to the distal portion of the first distal portion 11, the second branch stent 61 is crimped to the proximal portion of the third proximal portion 13, and the main body stent 65 is crimped to both the proximal portion of the first distal portion and the distal portion of the third proximal portion. Here, the first balloon section is bent and rests on the third balloon section.

[0066] As shown in Figure 6B, the medical device is delivered to the bifurcation of the vessel through a single ipsilateral access. Once the balloon catheter is deflated and removed, the bifurcation stent completely covers the bifurcation of the treated vessel (see Figure 6C).

[0067] Alternative devices and approaches for treating lesions in branched vessels are shown in Figures 7A to 7D. The device shown in Figure 7A corresponds to the device shown and described in Figure 5. The main stent 65 is placed adjacent to the bifurcation using a balloon catheter of the present invention and a single ipsilateral access site. To further cover the leg of the bifurcation, a first leg stent 161 is used for the first side branch using ipsilateral access, and a second leg stent 163 is used for the second side branch using contralateral access. The leg stents may be placed adjacent to the main stent or in a configuration that overlaps with the proximal portion of the main stent.

[0068] A similar approach is shown in Figures 8A to 8D. The main stent of this embodiment differs from the main stent shown in Figures 7A to 7D in that the main stent 65 of this alternative embodiment includes two wing-like structures 69a, 69b at its proximal end. Each of these wings reaches one of the lateral branches of the bifurcation, thereby increasing wall coverage and support in the transition region between the main body stent 65 and the lateral branch. When the lateral branch stents 161, 163 are used in the two subsequent delivery steps in the same manner as described in the embodiments of Figures 7A to 7D, the wings overlap with the distal portions of the lateral branch stents, thereby increasing wall coverage and support in the transition region between the main body stent 65 and the lateral branch stents 161, 163.

[0069] In other embodiments, a branch stent attached to the balloon catheter of the present invention includes a main body stent 65 and a branch stent 61 integrally formed with it. As shown in Figures 9A to 9C, the stent, including the main body stent 65 and the branch stent, is loaded into the balloon catheter by attaching the main body of the stent 65 to both the proximal portion of the first distal portion 11 and the distal portion of the third balloon portion 13, where the first balloon portion is bent onto the third balloon portion. The branch stent is then crimped to the proximal portion of the third proximal portion of the balloon so as to cover the branch of the bifurcation, i.e., the ipsilateral vessel, where the branch stent is used as the catheter access site.

[0070] As shown in Figures 10A to 10C, the stent, which includes a main body stent 65 and one branch stent 63, is loaded into the balloon catheter by attaching the main body of the stent 65 to both the proximal portion of the first distal portion 11 and the distal portion of the third balloon portion 13. Here, the first balloon portion is bent onto the third balloon portion. Here, the one branch stent 63 is crimped to the distal portion of the first distal portion of the balloon so that the side branch stent 63 covers the contralateral branch vessel, i.e., the vessel, of the bifurcation. In the second step, the second branch stent 161 may be deployed into the ipsilateral vessel using the same access site in the procedure.

[0071] In further embodiments of the present invention (Figures 11A to 11C), a first stent including a main body stent 65a and a first branch stent 63, and a second stent including a main body stent 65b and a second branch stent 61 are loaded into a balloon catheter by attaching the main bodies 65a and 65b of the first and second stents to both the proximal portion of the first distal portion 11 and the distal portion of the third balloon portion 13 so that they overlap. Here, the first balloon portion is bent onto the third balloon portion. Here, the first branch stent 63 of the first stent is pressed against the distal portion of the first distal portion 11 of the balloon. Here, the second branch stent 61 of the second stent is pressed against the proximal portion of the third proximal portion 13 of the balloon.

[0072] Herein, we refer to Figures 12 to 16 illustrating various embodiments of further aspects of the present invention. As described above, in some embodiments, a snare can be advanced from the contralateral side to capture the device's guidewire, facilitating the placement of the distal end of the stent or stent graft into the contralateral vessel. In certain embodiments, it is also preferable to introduce a sheath into the contralateral vessel, pass through the lesion, and place the tip of the sheath to allow contralateral sheath protection delivery of the stent or stent graft branch before deployment of the stent graft.

[0073] When the distal balloon portion supporting the stent or stent graft is retracted into the contralateral vessel by pulling the distal end of the guidewire, it is preferable that the first distal balloon portion supporting the stent and the sheath are aligned along their axes to ensure smooth entry of the distal balloon portion supporting the stent or stent graft, thereby avoiding damage to the stent or stent graft when entering the sheath. Such alignment of the first balloon portion and the sheath can be reinforced or ensured by an aligner. Accordingly, the present invention also relates to a balloon catheter for supporting a stent or stent graft, which includes an aligner distal to the distal end of the crimped stent or stent graft.

[0074] In some embodiments, such an aligner is attached to the distal portion of the catheter shaft. As shown in Figure 12, in the first embodiment, the aligner 200 is a bumper 201 attached to the catheter shaft 2 below the distal end of the distal balloon portion 11, which is distal to the distal end of the stent 63.

[0075] Figure 13 discloses an alternative embodiment of the aligner 200. The bumper 202 is attached to the catheter tip 40 distal to the distal end of the balloon 11. In both embodiments, the bumpers 201, 202 are dimensioned such that the outer diameter of the bumper is substantially the same as the outer diameter of the distal end portion of the stent or stent graft 63 crimped to the balloon. The diameter of the bumper may be the same as the diameter of the distal end of the crimped stent or stent graft, or it may be up to 10% larger or up to 20%, preferably 10%, preferably 5% smaller than the diameter of the distal end of the crimped stent or stent graft. The bumper may have any shape that is smooth enough to guide the catheter of the present invention smoothly into a vascular lesion or sheath, and the bumper may have a particularly spherical shape. The bumper may be fixedly attached to the catheter shaft and may be made from any suitable material having a surface smooth enough to ensure proper balloon and catheter function. Preferred materials are polymers or metal alloys.

[0076] In an alternative embodiment shown in Figure 14, the aligner 200 may be in the form of a skirt 203 attached to the distal portion of the catheter tip 40 at the distal end of the balloon 11. The skirt covers the distal balloon cone and the distal portion of the stent or stent graft 63 pressed against the balloon. The skirt may be made of a highly flexible material to ensure proper expansion of the stent during balloon inflation, or in an alternative embodiment (not shown), the skirt may have one or more longitudinal perforations that serve as predetermined break points to allow smooth and complete expansion of the stent.

[0077] In a further alternative embodiment, the catheter aligner 200 may be provided with guidewires 80, 500 that are pre-fixed or pre-loaded onto the catheter. As shown in Figure 15, the guidewire 500 includes a slotted tube that expands under tension to form a cage 205 around the guidewire. This cage is positioned adjacent to the distal end of the catheter and functions as the aligner 200.

[0078] Such a “caging” guidewire generally comprises a first proximal guidewire portion, a second distal guidewire portion, and a cage portion including a slotted tube. Here, the distal end of the proximal guidewire portion is fixedly attached to the distal end of the slotted tube, and the proximal end of the distal guidewire portion is fixedly attached to the proximal end of the slotted tube. In this way, the slotted tube cages out when the ends of the guidewire are pulled apart from each other. It is also possible to form the slotted tube using a shape memory metal alloy to ensure that the cage returns to its original flat structure when the tensile force is released. In an alternative embodiment, a metal spring may be fixed to the end of the slotted tube to ensure the cage elongates when the tensile force is released.

[0079] For example, one embodiment of a guidewire including such an aligner is shown in Figure 16, which is not an exhaustive example.

[0080] The guide wire 500 includes a metal core 501 that determines the individual stiffness of the guide wire, and an ePTFE-coated spring 502 surrounding the metal core. The spring and core are welded together at the proximal end of the guide wire 402. Furthermore, a proximal metal flat wire 505 is welded to the proximal end of the guide wire, and the proximal metal flat wire extends through the spring 502 parallel to the guide wire core 501.

[0081] A slotted tube 510 is provided, which can form a cage under tension that provides an alignment for the catheter. The tube may have 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or more slots. The slots may be arranged symmetrically around the tube or at irregular distances from one another.

[0082] The proximal end of the slotted tube is welded to the distal end of the proximal ePTFE-coated spring 502, and also to the proximal end of the metal spring 520 located below the slotted tube 510 and to the proximal end of the distal flat wire 506 at welding point 403. The metal core 501 and the proximal flat wire 305 extend through the tube and spring. The guidewire core extends further beyond the distal portion of the slotted tube 510. The distal end of the slotted tube 510 is welded to the proximal end of the distal ePTFE-coated spring 503, and to the distal end of the metal spring 520 and to the distal end of the proximal flat wire 505 at welding point 407. The distal end of the distal flat wire 506 is welded to the distal end of the distal end of the distal ePTFE-coated spring 503 at welding point 409.

[0083] In this configuration, when the guidewire is pulled at its distal end while its proximal end is fixed, the slotted tube 510 is compressed, forming a cage-like structure.

[0084] Due to the metal spring 520 located beneath the slotted tube 510, the slotted tube is stretched and flattened when the tensile force at the distal end is no longer present. The metal core 501 of the guidewire terminates immediately after the distal end of the tube. Thus, accidental pulling of the metal core is avoided. Furthermore, the metal core 501 moves within the slotted tube 510 and the distal ePTFE-coated spring 503.

[0085] This embodiment discloses, for example, one possible mechanism by which such a guidewire cage aligner may be implemented, but is not limited thereto. However, those skilled in the art will readily recognize any variations and modifications thereof.

[0086] It should be noted that any embodiment of the aligner described above can be used alone or in any combination thereof. Accordingly, the present invention relates to a balloon catheter comprising one or more aligners positioned distal to the distal end of a stent attached to a balloon.

[0087] The above is a complete description of preferred embodiments of the present invention, but various substitutions, modifications, and equivalents may be used. Various features of the embodiments disclosed herein can be combined or substituted for one another. Therefore, the above description should not be construed as limiting the scope of the present invention as defined by the appended claims. Furthermore, any combination in all possible variations of the elements described above is encompassed by the present invention unless otherwise indicated herein or unless it is clearly inconsistent with the context. It should be understood that the embodiments of the present invention are illustrative of the principles of the present invention. Other modifications that may be adopted are also within the scope of the present invention. Therefore, as an example, but not limiting, alternative configurations of the present invention may be used in accordance with the teachings herein.

Claims

1. A balloon catheter for delivering a branching stent to a branching vessel, The device includes a hub, a shaft, a single balloon connected to the shaft, and an expansion port of the hub that is in fluid communication with the single balloon. A balloon catheter comprising a single balloon including a first distal portion, a second central portion, and a third proximal portion, wherein in its delivery configuration, the first distal portion of the balloon is bent to the third proximal portion of the balloon so that the first distal portion and the third proximal portion of the balloon are adjacent to each other.

2. The balloon catheter according to claim 1, wherein the balloon catheter includes a guidewire lumen for housing a pre-loaded guidewire, and the guidewire lumen extends through the hub, the shaft, and the balloon.

3. The balloon catheter according to claim 1, wherein the balloon catheter includes a fixing guidewire that extends beyond the distal end of the balloon.

4. The single balloon is At least a first waist portion located between the first distal portion and the second central portion, At least the second waist portion between the second central portion and the third proximal balloon portion and A balloon catheter according to any one of claims 1 to 3, including the balloon catheter described in any one of claims 1 to 3.

5. The balloon catheter according to any one of claims 1 to 4, wherein the first distal portion and the third proximal portion of the single balloon are rotationally symmetrical and / or cylindrical and / or conical and / or stepped cylindrical.

6. The balloon catheter according to any one of claims 1 to 5, wherein the shape of the second central balloon portion of the single balloon is spherical.

7. The balloon catheter according to any one of claims 1 to 5, wherein the second central balloon portion of the single balloon is formed from a series of spherical balloon portions interrupted by one to ten waist portions.

8. The balloon catheter according to any one of claims 1 to 7, wherein the single balloon maintains its bent configuration when inflated in the branched blood vessel.

9. The balloon catheter according to any one of claims 1 to 8, wherein the balloon catheter includes a second balloon attached to the catheter shaft proximal to the single balloon, the second balloon having fluid communication with the second inflatable lumen.

10. The balloon catheter according to claim 9, wherein the second balloon has an outer diameter larger than the maximum diameter of the single balloon.

11. A balloon catheter according to any one of claims 1 to 10, wherein a stent is attached to the single balloon, and the main body of the stent is attached to both the proximal portion of the first distal portion and the distal portion of the third balloon portion while the first balloon portion is bent and resting on the third balloon portion.

12. A balloon catheter according to any one of claims 1 to 10, wherein a branch stent including a main body stent, a first branch stent, and a second branch stent is attached to the single balloon, the first branch stent is attached to the distal portion of the first distal portion, the second branch stent is attached to the proximal portion of the third proximal portion, and the main body of the stent is attached to both the proximal portion of the first distal portion and the distal portion of the third balloon portion while the first balloon portion is bent and rests on the third balloon portion.

13. The balloon catheter according to claim 12, wherein the main body stent portion, the first branch stent portion, and the second branch stent portion of the stent are integrally formed, or the main body stent portion, the first branch stent portion, and the second branch stent portion of the stent are each formed by a single stent.

14. The balloon catheter according to any one of claims 1 to 13, wherein the stent is a stent graft.

15. The balloon catheter according to any one of claims 11 to 14, wherein the balloon catheter includes one or more aligners positioned distal to the distal end of the stent attached to the balloon.

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