Introducer for crossing over kissing stents

Abstract

An introducer (10) for forming a working channel across two kissing stents (106,108) located in the common iliac arteries (102,104), the introducer comprising: an elongate tube (12); a first fixation device (14) mounted on the distal end of the elongate tube and a second fixation device (16) mounted on the proximal end of the elongate tube, the fixation devices being transitionable between a radially compact state and a radially expanded state; one or more channels (20,24) for expanding and contracting the fixation devices, wherein the elongate tube comprises a lumen for providing the working channel allowing a tool to be progressed from the proximal end to the distal end.

Description

[0001] Introducer for Crossing Over Kissing Stents

[0002] Field of the Invention

[0003] An introducer for forming a working channel across two kissing stents is disclosed. A method of providing a working channel across two kissing stents located in the common iliac arteries is also disclosed.

[0004] Background

[0005] Aortoiliac occlusive disease occurs when deposits (e.g., calcium) build up in and around the aortoiliac bifurcation. These deposits can impede blood flow and can lead to numerous symptoms including pain, numbness, or cramping in the lower limbs, and gangrene in the feet.

[0006] One established treatment is to implant kissing stents in the aortoiliac bifurcation. In this procedure, a first stent is implanted crossing from the aorta to one of the right and left common iliac arteries, and a second stent is implanted crossing from the aorta to the other of the right and left common iliac arteries. The superior ends of the two stents are generally positioned to be immediately adjacent one another or touching one another, with said ends located either within the inferior end of the aorta or within the aortoiliac bifurcation itself. In this arrangement, the stents are referred to in the art as “kissing stents”. Two examples of kissing stents are shown in Figures 1A and 1 B, respectively.

[0007] Once kissing stents are implanted within a patient, it is difficult or impossible to perform a crossover operation between the two common iliac vessels. A crossover operation is one in which a tool is inserted through an access in a first of the two common iliac arteries (e.g., the right common iliac) and is then advanced through this first common iliac artery to cross over into the second common iliac artery (e.g. into the left common iliac artery). This procedure is currently difficult or impossible to perform when kissing stents are already present due to the sharp bend that occurs at the aforementioned superior ends of the kissing stents. In this area, both kissing stents typically form two side-by-side apertures, each aperture facing substantially in the superior direction up into the aorta, i.e., towards a patient’s head. As such, any tool inserted from the inferior end of a first of the stents needs to perform a sharp U-turn when it exits from the first stent, in order to enter into the superior end of the other stent. It is desirable to reduce the number of accesses into a patient’s vasculature during surgery, as each access is a further infection risk and a further location that needs to heal after surgery. Thus, there is need in the art for apparatuses and methods by which a crossover operation between the common iliac arteries can be performed when kissing stents are already present within a patient.

[0008] Summary of Invention

[0009] According to a first aspect, there is provided an introducer for forming a working channel across two kissing stents located in the common iliac arteries, the introducer comprising: an elongate tube of non-porous material, the elongate tube having a proximal end and a distal end; a first fixation device mounted on the elongate tube and located proximate the distal end, the first fixation device being transitionable between a radially compact state and an radially expanded state; a second fixation device mounted on the elongate tube and located proximal of the first fixation device, the second fixation device being transitionable between a radially compact state and a radially inflated state; wherein the first fixation device, when in the radially expanded state, is spaced apart from the fixation device, when in the radially expanded state; and one or more channels for radially expanding and radially contracting the first and second fixation devices; wherein the elongate tube comprises a lumen for providing the working channel, the lumen for allowing a tool to be progressed along the tube from the proximal end to the distal end. In use, the lumen may optionally be used to guide a (therapeutic) tool around the relatively-sharp bend between the kissing stents, and allow the tool to access vasculature inferior to the second kissing stent. This may allow treatment on both sides of a patient’s body (i.e., in, or off-from, either common iliac artery) via a single access.

[0010] The introducer discussed above is suitable for forming a working channel across two kissing stents. However, the introducer may also form a working channel across the common iliac arteries even in the absence of kissing stents.

[0011] The first fixation device may be a first balloon, wherein the radially compact state of the first fixation device is a deflated state of the first balloon, wherein the radially expanded state of the first fixation device is an inflated or at least a partially- inflated state of the first balloon, and wherein the one or more channels includes a fluid channel for conveying fluid to and from the first balloon. Alternatively or additionally, the second fixation device may be a second balloon, wherein the radially compact state of the second fixation device is a deflated state of the second balloon, wherein the radially expanded state of the second fixation device is a fully-inflated or at least a partially-inflated state of the second balloon, and wherein the one or more channels includes a fluid channel for conveying fluid to and from the second balloon.

[0012] In use, the fixation devices will be expanded within a vessel to a size where they securely anchor the tube relative to the vessel. This may or may not be the fully expanded size of a balloon. That is, the balloon may be configured to have a maximum size / outer radius when fully inflated outside the body. This maximum outer radius may be larger than the vessel that the balloon is intended to be used within. In that case, in use, the balloon may be transitioned to its inflated state to attain a size sufficient to anchor the balloon within the vessel, and the size of the balloon in this inflated state may be less than its size in the fully inflated state outside the body. Put another way, in some examples, it may be sufficient to transition the balloon to an inflated state that is only partially inflated (i.e. , less than fully inflated).

[0013] The second fixation device may be spaced apart from the first fixation device by a section of the elongate tube, the section of the elongate tube having a length defined between a location where a distalmost end of the second fixation device connects to the elongate tube, and a location where a proximal-most end of the first fixation device connects to the elongate tube, wherein the section has a length greater than or equal to 5 centimetres. This length may ensure that, when the first fixation device is in or distal-of the second stent, the second fixation device is in or proximal-of the first stent. In some arrangements, when the fixation devices are radially expanded, the fixation devices do not touch either of the stents, which may optionally prevent the fixation devices from undesirably deforming the stents.

[0014] The lumen may have an internal diameter of at least 1 .33 mm, such that the lumen can accommodate a tool having a maximum outer diameter of 1.33 mm (4 French). This may optionally increase the range of tools that may be advanced through the lumen, and thereby enable a wider range of therapeutic treatments to be performed.

[0015] The first fixation device may be configured such that, when in the radially expanded state, a first flowpath exists between the first fixation device and an outer surface of the elongate tube for allowing fluid flow past the radially expanded first fixation device. This may optionally enable the introducer to be used for a longer time without negative effects on parts of the body that receive blood that passes through the iliac artery. In cases where the first fixation device is a balloon, the balloon may, for example, be the same design as the balloon used on the True™ Flow Valvuloplasty Perfusion Catheter produced by C.R. Bard, Inc, of New Jersey, USA.

[0016] The second fixation device may be configured such that, when in the radially expanded state, a second flowpath exists between the second fixation device and an outer surface of the elongate tube for allowing fluid flow past the inflated second fixation device. This may optionally enable the introducer to be used for a longer time without negative effects on parts of the body that receive blood that passes through the iliac artery. In cases where the second fixation device is a balloon, the balloon may, for example, be the same design as the balloon used on the True™ Flow Valvuloplasty Perfusion Catheter produced by C.R. Bard, Inc, of New Jersey, USA.

[0017] The elongate tube may be made of a composite material comprising a flexible portion and a reinforcement portion. The flexible portion may optionally allow better bending performance at a given location, while the reinforcement portion helps ensure a desired overall strength of the elongate tube.

[0018] A portion of the elongate tube that is located between the first and second fixation devices may be configured to have increased flexibility compared to the rest of the elongate tube. This may optionally provide better performance of the elongate tube at the location between the superior ends of the kissing stents where, typically, the greatest bending of the tube is required. This may optionally also prevent kinking of the elongate tube in this area.

[0019] The portion of the elongate tube may comprise a polymer material having lower durometer than a material forming the rest of the elongate tube. This may optionally provide easier manufacturing the elongate tube with the increased flexibility in this portion.

[0020] The elongate tube may comprise a fiber reinforced composite material; wherein, in the portion of the elongate tube that is located between the first and second fixation device, fibers of the fiber reinforced composite material are arranged in a first pattern that is different from a second pattern of fibers in another part of the fiber reinforced composite material. The first pattern may, for example, be a helical winding of fiber in the portion, the helix may circumscribe the elongate tube. The second pattern may, for example, be a braid of fibers. A helical winding within a fiber reinforced composite material may result in increased flexibility of the material compared to a fiber reinforced composite material having a braid of fibers. Suitable fibers for use in the fiber reinforced composite material include both metallic and non-metallic fibers. For example, suitable fibers include steel fibers, stainless steel fibers, carbon fibers, aramid fibers, and UHMWPE fibers.

[0021] One or more of the one or more channels may be formed in a wall of the elongate tube. That is, one channel may be formed in a wall of the elongate tube. In cases where one or both of the fixation devices are balloons, this one channel may be for inflating / deflating one of the balloons or for inflating / deflating both of the balloons. In another example, one channel may be formed in a wall of the elongate tube for inflating / deflating one of the balloons, while another channel for inflating / deflating another of the balloons is formed separately. Forming one or more of the channels in a wall of the elongate tube may optionally provide a more space-efficient way of inflating / deflating the balloons.

[0022] According to a second aspect, there is provided a system comprising a steerable dilator and the introducer of any of the above-described aspects; wherein the steerable dilator has a steerable tip. The steerable tip of the steerable dilator may optionally allow the steerable dilator to be more easily navigated around the relatively sharp bend between the superior ends of the kissing stents.

[0023] The steerable dilator may comprise two wires, each wire connected at or adjacent a proximal end of the steerable dilator and the two wires connected on opposite sides of the steerable dilator, the wires for steering the steerable tip. This may optionally provide a simple system for steering the tip, in which a user (e.g., a physician) pulls on one or other of the wires to bend the tip towards the pulled wire.

[0024] The system may further comprise a guidewire, wherein the steerable dilator has a channel configured to receive the guidewire therethrough. The steerable dilator may optionally be used to guide an end of the guidewire such that the guidewire is crossing over the two kissing stents. The introducer of the first aspect and the steerable dilator may then be advanced along the guidewire to the crossover position.

[0025] The steerable dilator may be sized to fit through the lumen of the elongate tube. The steerable dilator may optionally assist in guiding the introducer around the bend between the common iliac arteries at the aortoiliac bifurcation. The steerable dilator may then be removed.

[0026] According to a third aspect, there is provided a system comprising the introducer of any preceding claim and a tool, wherein the tool has a maximum outer diameter of at least 1.3 mm (4 French). The tool may be any kind of therapeutic tool, including tools for: POBA (“Plain Old Balloon Angioplasty”), DCB (“drug coated balloons”), Stents, Stent Grafts, Laser therapy, or Atherectomy. Such tools will typically be much larger than a guidewire and, typically, much less flexible too. The tool may be a bundle of the aforementioned tools. For example, the tool may be a bundle of a POBA tool and one or more stents. Other suitable combinations of the aforementioned tools bundled together into a single tool are also envisaged.

[0027] According to a fourth aspect, there is provided a method of providing a working channel across two kissing stents located in the common iliac arteries, the method comprising: advancing a distal end of an elongate tube of an introducer sequentially through a first kissing stent and a second kissing stent until the distal end is located distal of the second kissing stent, the elongate tube having a lumen for providing the working channel; radially expanding a first fixation device located on an outer surface of the elongate tube and proximate the distal end of the elongate tube to fix the distal end of the elongate tube relative to a first one of the common iliac arteries; and radially expanding a second fixation device located on the outer surface of the elongate tube and proximal of the first fixation device to fix a second location of the elongate tube relative to a second one of the common iliac arteries. The elongate tube thereby provides a working channel crossing over the iliac arteries. A tool may then optionally be advanced through the elongate tube, such that the tool can provide therapeutic treatment to a location downstream (with respect to blood flow coming from the heart) of second kissing stent. In this manner, a single access (e.g., in the patient’s leg, inferior to the first kissing stent) may be used to provide treatment on both the right common iliac artery side of the patient and the left common iliac artery side of the patient. Use of a single access may optionally reduce the infection risk and / or healing time for the patient.

[0028] The first fixation device may be a first balloon, wherein radially expanding the first fixation device includes inflating the first balloon. Alternatively or additionally, the second fixation device may be a second balloon, wherein radially expanding the second fixation device includes inflating the second balloon.

[0029] Prior to radially expanding the first fixation device, the elongate tube may be advanced to a position in which the first fixation device is located distal of an inferior end of the second kissing stent, wherein, at this position, the second fixation device is located proximal of an inferior end of the first kissing stent, such that after the first fixation device and second fixation device are radially expanded, the first radially expanded fixation device does not abut against either of the two kissing stents and that second radially expanded fixation device does not abut against either of the two kissing stents. This positioning of the fixation devices may optionally prevent damage to, or unwanted deformation of, either of the kissing stents.

[0030] A steerable dilator may be located in the lumen of the introducer, the steerable dilator having a steerable tip. The method may further comprise removing the steerable dilator after the step of advancing a distal end of an elongate tube of an introducer sequentially through a first kissing stent and a second kissing stent. The steerable dilator may optionally assist in guiding the introducer through the vasculature.

[0031] The step of removing the dilator may be performed after the step of radially expanding the first fixation device. This may optionally prevent undesired migration of the introducer while the steerable dilator is removed, because the introducer is anchored at one end by the first fixation device. The step of removing the dilator may be performed after the step of radially expanding the second fixation device. This may optionally further help prevent undesired migration of the introducer, because the introducer is anchored at two ends by the two fixation devices.

[0032] After the step of radially expanding a first fixation device, and prior to the step of radially expanding a second fixation device, the method may comprise applying pressure directed to advance the elongate tube and inflating the second fixation device while applying the pressure, such that the elongate tube is held in compression between the first radially expanded fixation device and the second radially expanded fixation device. This may optionally improve the rigidity of the elongate tube and thereby improve its performance in guiding the tool to cross over.

[0033] Brief Description of the Figures

[0034] Reference will now be made, by way of example only, to the accompanying drawings in which:

[0035] Figures 1A and 1 B show a known arrangement of kissing stents within the aortoiliac bifurcation;

[0036] Figure 2 shows an introducer;

[0037] Figure 3 shows the introducer advanced through a first kissing stent;

[0038] Figure 4 shows the introducer advanced through first and second kissing stents;

[0039] Figure 5 shows the introducer, crossing both kissing stents, with a first balloon inflated;

[0040] Figure 6 shows the introducer, crossing both kissing stents, with first and second balloons inflated;

[0041] Figure 7 shows a steerable dilator;

[0042] Figure 8 shows an end-on cross-sectional view of an alternative balloon design; and

[0043] Figure 9 shows a side-on cross-sectional view of the alternative balloon design of Figure 8.

[0044] Description

[0045] The terms “distal” and “proximal” used herein take their usual meanings in the art. That is, the “distal” refers to parts / regions located furthest from the care provider and “proximal” refers to parts / regions closest to the care provider. The terms “superior” and “inferior” used herein take their usual meanings in the art. That is, “superior” refers to the direction towards the patient’s head and “inferior” refers to the direction towards the patient’s feet.

[0046] Figures 1A and 1 B both show kissing stents 106,108 located in the aortoiliac bifurcation. In Figure 1A, the superior end of each of the stents 106,108 is located within the aorta 100, i.e., a few millimetres above the aortoiliac bifurcation. In Figure 1 B, the superior end of each stent is located within the aortoiliac bifurcation itself. The exact placement of the kissing stents will be decided by a physician and depends upon clinical indications, such as the degree of occlusion within the last few millimetres of the aorta. A first 106 of the kissing stents extends into the right common iliac artery 102, and a second 108 of the kissing stents extends into the left common iliac artery 104. Note that Figs 1A, 1 B, and 3-6 are all rendered as if the viewer is face-to-face with the patient, and thus the iliac artery depicted on the left-hand side of, for example, Fig 1A (i.e. “left” from the viewer’s perspective) is on the patient’s right hand side, and is thus the patient’s right common iliac artery. The superior direction (i.e., towards the patient’s head) is depicted on Figure 1A as is the inferior direction (i.e. towards the patient’s feet), and these orientations apply equally to all of Figures 1A, 1 B, and 3-6.

[0047] After kissing stents 106,108 have been implanted within a patient, it may become necessary to undertake further interventions at a later date. That is, a patient with kissing stents may be readmitted to hospital for further vascular treatment in the vicinity of the aorta 100 and / or common iliac arteries 102,104. It is desirable in certain situations to be able to access both common iliac arteries 102,104 via a single access, i.e., to perform a cross-over procedure. Use of a single access may reduce the infection risk and improve recovery time. However, the presence of kissing stents has heretofore impeded cross-over procedures, crossing from right- to-left or left-to-right common iliac arteries. This difficulty is largely due to the comparatively sharp bend that a tool must navigate around between the superior ends of the two kissing stents.

[0048] Figure 2 depicts an introducer 10 for forming a working channel across two kissing stents, (e.g., across the kissing stents 106,108 shown in Figs 1A or 1 B). The introducer 10 comprises an elongate tube 12 having a first balloon 14 and a second balloon 16 mounted thereon. The first balloon 14 is an example of a first fixation device. The second balloon 16 is an example of a second fixation device. The elongate tube 12 has a wall 12a which defines a lumen 18 which provides the working channel when the introducer 10 has crossed over from one common iliac artery to the other, as described in greater detail below. The elongate tube 12 is flexible. The elongate tube 12 is made of non-porous material, i.e., blood or other fluid cannot flow through the wall 12a of the tube. For example, the tube may be made of PEBA (known under the trade name of Pebax™), which is a polyether block amide. PEBA can be produced with a variety of durometers. Choosing a suitable durometer for all of or for different sections of the elongate tube may allow customisation of the flexibility of (sections of) the elongate tube. The working channel means that a (therapeutic) tool may be inserted into one end of the lumen 18 and advanced through the lumen 18 until it exits the other end of the introducer 12. The lumen 18 guides the tool and, in particular, guides the tool around the sharp bend at the superior ends of the kissing stents.

[0049] The tool may be any kind of tool for providing a type of therapy (e.g., therapy to the patient’s vasculature). The tool may be advanced along a guidewire, such as guidewire 50 depicted in Figures 3-7. It should be noted that guidewires typically have a relatively high level of flexibility in order to initially be navigated around tortuous paths, and further, the guidewire is not typically anchored to the arteries. Thus, if a user advances a relatively-inflexible tool along an (unanchored) guidewire, the guidewire may be pulled out of its position rather than, as desired, guiding the tool around a sharply-curved path. Thus, as described below, the introducer 10 gets anchored within the patient’s vasculature by the balloons 14,16, and the elongate tube 12 is therefore anchored too. This means that a tool that is being advanced through the lumen 18 bears against the wall 12a and, due to the tube 12 being anchored within vasculature by the balloons 14,16, the tool is forced to follow the path defined by the lumen 18.

[0050] Example tools include, but are not limited to, tools for: POBA (“Plain Old Balloon Angioplasty”), DCB (“drug coated balloons”), Stents, Stent Grafts, Laser therapy, Atherectomy, BTK (“below the knee”) therapy etc. The smallest currently available tools for such therapies have a diameter of around 4 French (1.3 mm). Thus, the lumen 18 may have a diameter of greater than 4 French (1.3 mm), so it can accommodate any of the aforementioned tools having a diameter of 4 French and greater. A guidewire 50 is not a tool within the meaning used here, as a guidewire cannot by itself provide any therapeutic effect or treatment, but merely guides tools that can provide therapeutic effect.

[0051] A first inflation lumen 24 may be formed in the wall 12a such that the first inflation lumen 24 is not in fluid communication with the lumen 18. The first inflation lumen 24 extends distally along the tube 12 and connects to the first balloon 14 at a first aperture 26. The first inflation lumen 24 may convey fluid (e.g., air or saline or other suitable fluid) to and from the first balloon 14 to inflate and deflate the first balloon 14. The deflated state of the first balloon is an example of a radially compact state of a first fixation device. The inflated state of the first balloon is an example of a radially expanded state of the first fixation device.

[0052] A second inflation lumen 20 may be formed in the wall 12a such that the second inflation lumen 20 is not in fluid communication with either of the lumen 18 and first inflation lumen 24. The second inflation lumen 20 extends distally along the tube 12 and connects to the second balloon 16 at a second aperture 22. The second inflation lumen 20 may convey fluid (e.g., air or saline or other suitable fluid) to and from the second balloon 16 to inflate and deflate the second balloon 16. The deflated state of the second balloon is an example of a radially compact state of a second fixation device. The inflated state of the second balloon is an example of a radially expanded state of the second fixation device.

[0053] With this configuration, the first and second balloons 14,16 may therefore be independently inflated and deflated.

[0054] The first balloon 14 is located at or close-to a distal end 28 of the introducer 10. That is, the first balloon 14 is located proximate to the distal end 28. For example, a distalmost point 14a of the first balloon 14 where the first balloon 14 connects to the tube 12 may be located either at the distal end 28 of the introducer 10, or may be located slightly proximal of the distal end 28 (e.g., by a few millimetres). The introducer 10 has a proximal end 29 as well, such that the tube 12 extends from the distal end 28 to the proximal end 29.

[0055] The second balloon 16 is located proximal of the first balloon 14 by a significant distance, i.e., the balloons are not immediately adjacent one another. More precisely, there is a region 30 of the tube wall 12a that has a length D measured between a distalmost point 16a of the second balloon 16 where the second balloon 16 connects to the tube 12 and a proximalmost point 14b of the first balloon 14 where the first balloon 14 connects to the tube 12.

[0056] The second balloon 16 may optionally be located proximate the proximal end 29 of the tube. Alternatively, the second balloon 16 may be located more distant from the proximal end 29. Indeed, the second balloon 16 may be located within the distalmost half of the elongate tube. Put another way, the elongate tube 12 may extend for a significant distance proximal of the second balloon 16 and may even, in use, extend through the access and outside the patient. A haemostatic valve may optionally be connected to an end of the elongate tube 12 outside the patient.

[0057] The aforementioned length D is measured along the tube wall 12a, and so this length D does not substantially change when the tube 12 bends in use (barring any small compression or expansion of the flexible tube along its length during use). When the tube is in an unloaded state, length D will typically be 5 cm or more, and may be greater than 6 cm, greater than 7 cm, greater than 8 cm, or greater than 9 cm. In one example, the length D is greater than 5 cm and less than 20 cm, and preferably less than 15cm.

[0058] The tube 12 is flexible and, before use, is generally straight (unless bent e.g., by a user). As described below, in use, a significant bend will be formed in the region 30 between the two balloons 14,16. The bend may be up to 180 degrees (e.g., a ll-bend). The tube wall 12a may be formed to have increased flexibility in the region 30, either along the entire length D of the region 30, or along a portion of the region 30. The flexibility of the tube wall 12a may be selected in a number of different ways. For example, the elongate tube may be formed of a polymer, such as PEBA (e.g., Pebax™). The elongate tube 12 may be made from a combination of materials. For example, the elongate tube 12 may be made from a low-friction inner liner (such as PTFE) and an outer jacket material (such as Pebax™). Optionally, a reinforcement braiding (such as stainless steel braiding) may be provided radially outward of the low-friction inner liner. Optionally, the outer jacket may be provided over the inner liner and then the jacket and liner may be melted together under heat and pressure. Different durometers of Pebax™ are commercially available. The tube wall 12a may have sections having different durometers from one another. For example, the elongate tube 12 may be configured such that some or all of the region 30 has a lower durometer than other portions of the wall 12a. Lower durometer material typically corresponds closely to greater flexibility of a given item made from that material. Alternatively or additionally, the tube wall 12a may contain a reinforcement material. The reinforcement material may, for example, be strands of high-strength material (such as fibers of steel, stainless steel, aramid, carbon, or UHMWPE) formed into various shapes. Such shapes include, for example, a braid or a spiral. The durometer of a given section of tube wall 12a may be adjusted by modifying the shape of the reinforcement material. For example, a section of wall 12a containing a spiral shape of reinforcement material may have a greater flexibility than a similar section of wall 12a having a braided reinforcement material.

[0059] Use of the introducer 10 in a crossover procedure will now be described in relation to Figures 3 to 6. For ease of description, the described crossover procedure is from the right common iliac artery to the left common iliac (i.e., a “right-to-left crossover”). However, it will be understood that the same steps may be undertaken for crossing over from the left common iliac artery to the right common iliac artery (i.e., a left-to-right crossover).

[0060] Figure 3 depicts the aorta 100, right common iliac artery 102, and left common iliac artery 104. A first kissing stent 106 has a superior end 106a and an inferior end 106b. The inferior end 106b of the first kissing stent 106 is located in the right common iliac artery 102. A second kissing stent 108 has a superior end 108a and an inferior end 108b. The inferior end 108b of the second kissing stent 108 is located in the left common iliac artery 104. In the example shown in Figures 3-6, the superior ends 106a, 108a of the two kissing stents are located within the aortoiliac bifurcation. However, the superior ends 106a, 108a may extend into the aorta 100 (e.g., as shown in Figure 1A).

[0061] First, an access is formed into a location of the right common iliac artery 102 that is inferior of the first kissing stent 106. A guidewire 50 is inserted through the access and advanced through the first kissing stent 106 from the inferior end 106b to the superior end 108. The guidewire 50 is then advanced into the second kissing stent 108 from its superior end 108a and advanced further to extend out of its inferior end 108b. Guidewires are typically far more flexible than catheter tubes, and this flexibility typically allows the guidewire 50 to be guided through the kissing stents 106,108 in this manner. There also exist small guiding catheters, such as angiographic catheters, with various designs of tip that may be used that may assist in guiding the guidewire as it is advanced through the patient’s vasculature. Typically, a steerable dilator or angiographic catheter may be used while inserting the guidewire 50. The guidewire 50 may be any suitable guidewire for and is not limited to any particular design or brand.

[0062] A steerable dilator 40 may optionally be used in situations when there is a larger angle (such as a U-bend) between the two superior ends 106a, 108a of the two stents 106,108. With such large angles, it may be difficult to guide a (non- steerable) guidewire around the sharp bend. In this case, the steerable dilator 40 may be used to direct the guidewire 50 around the sharp bend so that the guidewire 50 may be advanced into the second of the two stents 108.

[0063] Once the guidewire 50 is in place, the introducer 10 is inserted (optionally, along with the steerable dilator 40 as well). The following procedure will be described with reference to the guidewire 50 and introducer 10, but it is to be understood that essentially the same process applies when a steerable dilator 40 is additionally present (e.g., located within the lumen 18 and extending out from a distal end of the introducer 10).

[0064] As shown in Figure 3, the introducer 10 is slid onto the guidewire 50 (i.e., so the lumen 18 surrounds the guidewire 50) outside the patient and then is advanced into the right common iliac 102. It is advanced along the guidewire 50 through the first kissing stent 106, from the inferior end 106b to the superior end 106a.

[0065] As shown in Figure 4, the introducer 10 is then advanced further along the guidewire 50, bending primarily in the region 30 between the two balloons 14,16, so that the distal end 28 of the introducer 10 advances through the second kissing stent 108 from its superior end 108a to its inferior end 108b. The introducer 10 is advanced until the entire first balloon 14 has passed fully through the second kissing stent 108. In this position, there is a significant bend B in the elongate tube 12, and this bend B is in the region 30 between the two balloons 14,16 and between the superior ends 106a, 108a of the kissing stents 106,108. In the example shown, the elongate tube 12 has bent slightly more than 90 degrees. That is, the tube 12 follows a generally straight line through the first kissing stent 106 and then is bent off from this straight line by slightly more than 90 degrees, in order to extend through the second kissing stent 108.

[0066] The inferior end of the aorta has a diameter that is typically around 30mm or less in a full-grown adult. Thus, the introducer 10 must be flexible enough to accommodate a bend of (in the case depicted in the figures) more than 90 degrees within a space of less than 30 mm.

[0067] As shown in Figure 4, when the first balloon 14 is located distal of the second kissing stent 108, the second balloon 16 is located proximal of the first kissing stent 106. Put another way, when the proximalmost end 14b of the first balloon 14 is located inferior to the inferior end 108b of the second kissing stent 108, the distalmost end 16a of the second balloon 16 is located inferior to the inferior end 106b of the first kissing stent 106. This positioning of the balloons 14,16 relative to the kissing stents 106,108 may be ensured by selecting an appropriate length D. The appropriate length D may be determined for a given patient by first knowing the length of the two kissing stents 106,108 (which may be measured by imaging or may be already known from the patient’s medical records) and adding a suitable length to accommodate the path that the bent length of the tube 12 will take between the superior ends 106a, 108a of the kissing stents 106,108. The user (e.g., physician) may then select an introducer having a length D equal to or greater than the length so-determined.

[0068] The next step is shown in Figure 5. The first balloon 14, which is now located distal of the inferior end 108b of the second kissing stent 108, is inflated, e.g., via the first inflation lumen 24. The first balloon 14 is sized such that, when it is fully inflated, it loads against the walls of the left common iliac artery 104. Thus, when the first balloon 14 is inflated, the distal end 28 of the introducer 10 is anchored (at a first point) in the left common iliac artery. In an alternative, not shown, the first balloon 14 may be inflated within the second kissing stent 108.

[0069] At this point, the user (e.g., physician) either inflates the second balloon 16 immediately or, alternatively, may advance the introducer 10 slightly before inflating the second balloon 16. If the user chooses to advance the introducer 10 slightly in this manner, there will be a slight compressive stress along the length of the tube 12 between the two balloons 14,16. This may give the tube 12 greater resistance to bending (i.e. to appear more rigid) when a tool is inserted therethrough and thus the tube 12 may provide a greater guiding force on the tool. The second balloon 16 is sized such that, when it is fully inflated, it loads against the walls of the right common iliac artery 102. Thus, when the second balloon 16 is inflated, the introducer 10 is anchored in the right common iliac artery 102. The second balloon 16 therefore provides a second anchor point fixing the tube 12 between the two common iliac arteries 102,104. In an alternative, not shown, the second balloon 16 may be inflated within the first kissing stent 106.

[0070] In an alternative, both balloons 14,16 may be inflated / deflated via a common inflation channel, such that the balloons are inflated / deflated simultaneously with one another. In this case, the balloons are inflated when the first balloon has been advanced to the desired location within, or inferior to, the second kissing stent. This alternative may optionally allow a simpler design of the elongate tube 12 to only have one inflation channel.

[0071] Once the introducer 10 is anchored by the two balloons 12,14, it provides a working channel between the two common iliac arteries 102,104. This means that a user can insert a tool via the same access site as was used by the introducer (i.e. in the right common iliac artery 102) and the user may advance the tool along the right common iliac artery 102, through the lumen 18 of the introducer 10, and into the left common iliac artery 104. The wall 12 of the lumen 18 guides the tool and provides sufficient resistance so that the tool bends around the bend B. This resistance from the wall 12a that guides the tool around the bend B can be much greater than the guiding force provided by a guidewire 50, because the introducer 10 is anchored to the two common iliac arteries 102,104. That is, the guidewire 50 requires a relatively high level of flexibility in order to initially be navigated around the bend B (optionally, with the assistance of a steerable dilator 40). The guidewire 50 is not anchored to the arteries 102,104. Thus, if a user advances a relatively- inflexible tool along an unanchored guidewire 50, the guidewire 50 may be pulled out of the second kissing stent(s) rather than the guidewire 50 guiding the tool around the bend B, as desired.

[0072] Put another way, the process described above first involves inserting a steerable or otherwise highly-flexible instrument (i.e., guidewire 50 and, optionally steerable dilator 40) through the kissing stents 106,108. The process then involves inserting the introducer 10 through the kissing stents 106,108, the introducer 10 being somewhat less flexible / less steerable than the aforementioned initial instrument. The introducer 10 then gets anchored in the iliac arteries 102,104 by the balloons 14,16. Finally an even-less-flexible tool may be inserted and may cross over the iliac arteries 102,104, this tool being guided along its path by the tube 12 of the (anchored) introducer 10.

[0073] The introducer 10 therefore may be designed to have sufficient flexibility, particularly in the region 30, such that it bends to follow the guidewire 50 during advancement through the two kissing stents 106,108, rather than pull out the guidewire 50 from the second kissing stent 108. The introducer 10 then gets anchored by the balloons 14,16 and the material of the wall 12a provides sufficient bending force on a tool so as to properly guide the tool around the bend B. As discussed above, the first balloon 14 is distal of the second kissing stent and the second balloon 16 is proximal of the first kissing stent. This means that the balloons 14,16 do not load against the kissing stents 106,108, which could disrupt the stents’ position and / or shape. The tube 12 provides a barrier between the stents 106,108 and the tool, which may protect the stents and the tool from interfering with or damaging one another.

[0074] Alternatively, in some circumstances, it may be desired to inflate the first balloon 14 within the second kissing stent 108 and / or to inflate the second balloon 16 within the first kissing stent 106. The kissing stents are already implanted in the patient and so inflating one or both of the balloons within a respective stent may anchor the elongate tube relative to that stent and thereby anchor the introducer 10 relative to that common iliac artery. This may optionally allow a shorter length D between the two balloons 14,16.

[0075] Figure 7 depicts a steerable dilator 40. The steerable dilator may be used in addition to the guidewire 50. The steerable dilator 40 may be sized to fit inside the lumen 18 of the introducer 10. In use, the steerable dilator 40 may thus be located inside the introducer 10 and may assist with guiding the introducer 10 around the bend so that the introducer 10 crosses over the two stents 106,108. The steerable dilator 40 has a tip 42 and two wires 44a, 44b. A first of the two wires 44a is connected to a first side of the tip 42, and a second of the two wires 44b is connected to a second side of the tip 42, opposite the first side. Each of the wires 44a, 44b extends in a respective channel 46a, 46b along the dilator 40. In use, the tip 42 is the proximal end of the steerable dilator 40 and the wires 44a, 44b extend distally. Pulling on the first wire 44a bends the tip in one direction (towards the first wire) and pulling on the second wire 44b bends the tip in the opposite direction. In this manner, the tip of the steerable dilator 40 can be bent at will. This allows the steerable dilator 40 to navigate through vessels in a controllable manner. In particular, through use of the wires 44a, b, the steerable dilator 40 can be navigated to bend around the bend B to pass from the first kissing stent 106 to the second kissing stent 108. The steerable dilator 40 may be used, for example, to help steer the guidewire 50 around the sharp bend at the superior ends of the two stents 106,108. The guidewire 50 may then be advanced in the inferior direction through the second stent 108. The steerable dilator 40 and introducer 10 may then be advanced along the guidewire 50 through the second stent 108. In this process, the steerable dilator may assist in guiding the introducer 10 smoothly around the bend between the two stents 106,108 and through the second stent 108.

[0076] The steerable dilator may be longer than the introducer 10. The steerable dilator 10 may be arranged such that steerable dilator 40 is inside the lumen 18 of the introducer 10 and the tip 42 of the steerable dilator 40 is distal of the distal end of the introducer 10. That is, in one example, the steerable dilator 40 shown in Figure 7 may fit inside the lumen 18 of the introducer shown in Figure 2. This combination of steerable dilator 40 and introducer 10 may be used in the same manner as depicted for just the introducer 10 (and guidewire 50) in Figures 3-6.

[0077] Once the steerable dilator 40 and introducer 10 have been navigated through the two kissing stents 106,108, the balloons 14,16 may be inflated, as described above. The steerable dilator 40 may also be removed at this point.

[0078] The first balloon 14 may be configured to allow blood flow past the balloon when in the inflated state. That is, in the inflated state, there may be a flowpath between an outer surface of the elongate tube 12 and an inner side of the balloon 14. One example of such a balloon is shown in Figure 8.

[0079] Alternatively or additionally, the second balloon 16 may be configured to allow blood flow past the balloon when in the inflated state. That is, in the inflated state, there may be a flowpath between an outer surface of the elongate tube 12 and an inner side of the balloon 16. One example of such a balloon is shown in Figure 8.

[0080] That is, the design of balloon shown in Figure 8 may be used for either the first balloon 14, or for the second balloon 16, or for both of the first and second balloons 14,16.

[0081] Figure 8 depicts an end-on view of the elongate tube 12 and the lumen 18. A plurality of balloon units 60a-n are connected to one another to form (in the inflated state) a generally annular configuration. The plurality of balloon units 60a-n are enclosed in a sheath 64 that forms the outermost surface of the balloon, i.e. the surface that, in use, contacts a vascular wall. Each balloon unit 60a-n is connected via a unit inflation lumen 62a-n to the elongate tube 12. The unit inflation lumens 62a-n are fed from a common source, such as first inflation lumen 24 or second inflation lumen 20 (or a common inflation lumen for both balloons), such that all balloon units 60a-n of a given balloon inflate simultaneously. When the balloon of Figure 8 is inflated, there is a flow path 66 that allows fluid (e.g. blood) to flow between the balloon and the outer surface of the tube 12. Figure 9 depicts a sideview of the balloon of Figure 8.

Claims

CLAIMS:

1. An introducer for forming a working channel across two kissing stents located in the common iliac arteries, the introducer comprising: an elongate tube of non-porous material, the elongate tube having a proximal end and a distal end; a first fixation device mounted on the elongate tube and located proximate the distal end, the first fixation device being transitionable between a radially compact state and a radially expanded state; a second fixation device mounted on the elongate tube and located proximal of the first balloon, the second fixation device being transitionable between a radially compact state and a radially expanded state; wherein the first fixation device, when in the radially expanded state, is spaced apart from the second fixation device, when in the radially expanded state; and one or more channels for radially expanding and radially contracting the first and second fixation devices; wherein the elongate tube comprises a lumen for providing the working channel, the lumen for allowing a tool to be progressed along the tube from the proximal end to the distal end.

2. The introducer according to claim 1 , wherein the first fixation device is a first balloon, wherein the radially compact state of the first fixation device is a deflated state of the first balloon, wherein the radially expanded state of the first fixation device is an inflated or at least a partially-inflated state of the first balloon, and wherein the one or more channels includes a fluid channel for conveying fluid to and from the first balloon; and / or wherein the second fixation device is a second balloon, wherein the radially compact state of the second fixation device is a deflated state of the second balloon, wherein the radially expanded state of the second fixation device is a fully-inflated or at least a partially-inflated state of the second balloon, and wherein the one or more channels includes a fluid channel for conveying fluid to and from the second balloon.

3. The introducer according to any preceding claim, wherein the second fixation device is spaced apart from the first fixation device by a section of the elongate tube, the section of the elongate tube having a length defined between a location where a distalmost end of the second fixation device connects to theelongate tube, and a location where a proximal-most end of the first fixation device connects to the elongate tube, wherein the section has a length greater than or equal to 5 centimetres.

4. The introducer according to any preceding claim, wherein the lumen has an internal diameter of at least 1.33 mm (4 French), such that the lumen can accommodate a tool having an outer diameter of 1 .33 mm (4 French).

5. The introducer according to any preceding claim, wherein the first fixation device is configured such that, when in the radially expanded state, a first flowpath exists between the first fixation device and an outer surface of the elongate tube for allowing fluid flow past the inflated first fixation device.

6. The introducer according to any preceding claim, wherein the second fixation device is configured such that, when in the radially expanded state, a second flowpath exists between the second fixation device and an outer surface of the elongate tube for allowing fluid flow past the inflated second fixation device.

7. The introducer according to any preceding claim wherein the elongate tube is made of a composite material comprising a flexible portion and a reinforcement portion.

8. The introducer according to any preceding claim wherein a portion of the elongate tube that is located between the first and second fixation devices is configured to have increased flexibility compared to the rest of the elongate tube.

9. The introducer according to claim 8, wherein the portion of the elongate tube comprises a polymer material having lower durometer than a material forming the rest of the elongate tube.

10. The introducer according to claim 8 or 9, wherein the elongate tube comprises a fiber reinforced composite material; wherein, in the portion of the elongate tube that is located between the first and second fixation device, fibers of the fiber reinforced composite material are arranged in a first pattern that is different from a second pattern of fibers in another part of the fiber reinforced composite material.11 . The introducer of any preceding claim, wherein one or more of the one or more channels for radially expanding and radially contracting the first and second fixation device is formed in a wall of the elongate tube.

12. A system comprising a steerable dilator and the introducer of any preceding claim; wherein the steerable dilator has a steerable tip.

13. The system according to claim 12, wherein the steerable dilator comprises two wires, each wire connected at or adjacent a proximal end of the steerable dilator and the two wires connected on opposite sides of the steerable dilator, the wires being for steering the steerable tip.

14. The system of any of claims 12 or 13, further comprising a guidewire, wherein the steerable dilator has a channel configured to receive the guidewire therethrough.

15. The system of any of claims 12 to 14, wherein the steerable dilator is sized to fit through the lumen of the elongate tube.

16. A system comprising the introducer of any preceding claim and a tool, wherein the tool has a maximum outer diameter of at least 1 .3 mm (4 French).

17. A method of providing a working channel across two kissing stents located in the common iliac arteries, the method comprising: advancing a distal end of an elongate tube of an introducer sequentially through a first kissing stent and a second kissing stent until the distal end is located distal of the second kissing stent, the elongate tube having a lumen for providing the working channel; radially expanding a first fixation device located on an outer surface of the elongate tube and proximate the distal end of the elongate tube to fix the distal end of the elongate tube relative to a first one of the common iliac arteries; and radially expanding a second fixation device located on the outer surface of the elongate tube and proximal of the first fixation device to fix a second location of the elongate tube relative to a second one of the common iliac arteries.

18. The method according to claim 17, wherein the first fixation device is a first balloon, wherein radially expanding the first fixation device includes inflating the first balloon; and / or wherein the second fixation device is a second balloon, wherein radially expanding the second fixation device includes inflating the second balloon.

19. The method according to claim 17 or 18, wherein, prior to expanding the first fixation device, the elongate tube is advanced to a position in which the first fixation device is located distal of an inferior end of the second kissing stent, wherein, at this position, the second fixation device is located proximal of an inferior end of the first kissing stent, such that after the first fixation device and second fixation device are inflated, the first inflated fixation device does not abut against either of the two kissing stents and that second radially expanded fixation device does not abut against either of the two kissing stents.

20. The method according to any of claims 17 to 19, wherein a steerable dilator is located in the lumen of the introducer, the steerable dilator having a steerable tip the method further comprising removing the steerable dilator after the step of advancing a distal end of an elongate tube of an introducer sequentially through a first kissing stent and a second kissing stent.

21. The method according to claim 20, wherein the step of removing the dilator is performed after the step of radially expanding the first fixation device, or wherein the step of removing the dilator is performed after the step of radially expanding the second fixation device.

22. The method according to any of claims 17 to 21 , wherein, after the step of radially expanding a first fixation device, and prior to the step of radially expanding a second fixation device, the method comprises applying pressure directed to advance the elongate tube and radially expanding the second fixation device while applying the pressure, such that the elongate tube is held in compression between the first radially expanded fixation device and the second radially expanded fixation device.

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