Dual steerable sheath and method for deployment of medical devices - Patents.com

Abstract

The present invention relates to a dual steerable sheath, a delivery system comprising such a sheath, and a method for the deployment of a medical device, such as a replacement heart valve prosthesis, in a patient's heart.

Description

[Technical field]

[0001] The present invention relates to a dual steerable sheath, a delivery system comprising such a sheath, and a method for the deployment of a medical device, such as a heart valve prosthesis, in a patient's heart.

[0002] Minimally invasive techniques have advanced over the past few decades and are now accepted in many medical disciplines.

[0003] Minimally invasive techniques now allow many medical disciplines to treat patients and allow treatment of patients who would otherwise be unable to be adequately treated due to their physical condition and the risks associated with surgery. Many such minimally invasive procedures employ delivery systems intended to deliver medical devices to a desired target site.

[0004] In particular, in recent years, heart valve diseases and defects have been treated with increasing success, examples being transapical, transjugular and transfemoral procedures for heart valve replacement therapy, such as aortic or mitral heart valve repair.

[0005] In many cases, a stent-based prosthesis having a tissue-based replacement valve is used and implanted to replace the native heart valve. The replacement heart valve is implanted by a catheter or delivery system.

[0006] The replacement heart valve must be crimped and loaded into a delivery system. The delivery system is then introduced, for example, into the patient's vasculature and directed to the target site. At the target site, due to the particular geometry of the patient, the distal portion of the delivery system carrying the replacement heart valve must be positioned very precisely before deployment in order to achieve a flawless deployment. A flawless and precise deployment is crucial for the successful functioning of the implanted device.

[0007] In known delivery systems, various designs have been developed to provide a steerable distal portion for more precise deployment.

[0008] The correct deployment of a medical device is very complicated because not only must the medical device be pushed through the patient's vasculature, but also the medical device must be bent, such as by changing direction or changing angles, and navigated to the target site. Ultimately, not only must the correct site be reached, but it is also desirable to achieve a specific three-dimensional positioning, including, among other things, such a position, a certain angle, and a uniform distance from the natural tissue, for example, within the cavity.

[0009] Thus, there is a need for a device that allows for precise three-dimensional positioning of a distal portion carrying a medical device, and that allows for defined and controlled deployment of the medical device.

[0010] One problem with current delivery systems is the inability to precisely place the medical device at a desired target site.

[0011] In particular, it is problematic to position the distal part of the delivery system such that the positioning of the distal part of the delivery system can be achieved at all desired three-dimensional levels and / or such that an accurate and desired positioning of the capsule carrying the medical device can be achieved for the subsequent deployment step.

[0012] In particular, it is problematic that even the steerable solutions of the prior art are unable to enable the desired and optimal positioning of the replacement device with respect to a certain angle and / or its distance relative to the natural environment and / or the desired angle relative to the deployment plane.

[0013] Thus, known delivery systems do not allow the replacement device within the delivery system to be oriented and positioned in an optimal three-dimensional position prior to the release step, which represents a disadvantage in that the final implantation position may be inaccurate, leading to a non-optimal final positioning within the patient.

[0014] Accordingly, one objective is to provide a means to allow better delivery of the prosthesis and more accurate positioning of said prosthesis at the target site, or at least to reduce or essentially avoid the disadvantages of the prior art.

[0015] Another object is to provide a means for better three-dimensional actuation and positioning of medical replacement devices prior to deployment, or to at least reduce or essentially avoid the disadvantages of the prior art.

[0016] Another object is to provide means, which can be combined with a delivery system, for better three-dimensional actuation and positioning of a medical replacement device prior to deployment, or for at least reducing or essentially avoiding the disadvantages of the prior art.

[0017] Another object is to provide a method for better three-dimensional actuation and positioning of medical replacement devices prior to deployment, or to at least reduce or essentially avoid the disadvantages of the prior art.

[0018] Summary of the Disclosure In one aspect, the present disclosure relates to a sheath designed to be dual-actuatable and dual-bendable in two different directions, eg, essentially counter-bendable and dual-actuatable.

[0019] In another aspect, the present disclosure relates to a delivery system consisting of a dual steerable sheath or an S-shaped steerable sheath and a delivery catheter for a medical device, such as a replacement heart valve.

[0020] In another aspect, the present disclosure relates to a system including a double or S-shaped steerable sheath, a medical device, such as a prosthesis or replacement heart valve, and a catheter.

[0021] In another aspect, the present disclosure relates to a method for three-dimensional positioning of a distal portion of a steering sheath and / or a distal catheter capsule carrying a medical device, such as a heart valve, for improved deployment.

[0022] In another aspect, the present disclosure relates to a method of deploying a medical device at a target site within a patient, such as a native heart valve to be replaced. [Brief description of the drawings]

[0023] Preferred embodiments of the present disclosure are illustrated in the figures. [Figure 1] 1A-1C illustrate steerable sheaths with ideal bending compared to the prior art and embodiments according to the present disclosure. Left: The image on the left shows an ideal one-way sheath bending. This bending is targeted to be achieved with a pull wire that runs through the entire length of the steerable sheath, for which a softer material is used at the distal end of the sheath and a harder material is used proximal to the sheath. This would, in theory, only bend the distal end of the sheath. Middle: However, because the pull wire runs through the entire length of the sheath, it also affects the entire sheath (middle image), resulting in not only bending the tip of the sheath, but the entire sheath bowing forward. The proximal side of the sheath bends less due to the stiffer material, but still bows slightly. This causes the tip of the sheath to poke downward and not coincide with the desired target point. Right: The image on the right shows a preferred embodiment according to the present disclosure, where a second, counter-acting bend is introduced, which advantageously achieves straightening of an undesired bend in the proximal end of the sheath, thereby aligning the tip of the sheath with a desired target point at a desired three-dimensional location. [Diagram 2]1 illustrates the bending possibilities of a steerable sheath according to the prior art. The figure shows the range of bending that the sheath can achieve, with the undesirable bending achieved by a single pull wire. This design can only reach one target point per horizontal and vertical plane. [Diagram 3] 1 illustrates a preferred embodiment according to the present disclosure, incorporating a counter action bending mechanism allows both bendings to be adjusted to advantageously reach different target points within one horizontal plane. [Figure 4] 1 illustrates a preferred embodiment according to the present disclosure. By adjusting the distal and proximal bends, many more potential target points can be reached. Additionally, by actuating both bends, a smaller overall radius can be achieved, which advantageously allows for bending in smaller anatomical structures. [Diagram 5] 1 illustrates a preferred embodiment according to the present disclosure. Typically, when deploying an implant, e.g. a heart valve prosthesis, the best position of the delivery system is perpendicular (90°) to the implantation site (104), which may also mean the implantation surface. This ensures that the implant is not deployed at an angle. To allow unhindered deployment by the catheter carrying the intermediate device, i.e. to avoid the implant being deployed within the sheath, a certain pre-defined distance is required between the distal end of the steerable sheath and the implantation site. Thus, the distance "X" is determined, for example, by the contracted length of the medical device within the capsule of the catheter. By dual steering of the sheath (105), the distal end of the steerable sheath (105) can be directed to the desired target point (106). Thus, the present invention advantageously achieves that the catheter with the attached medical device can be pushed distally out of the steerable sheath and positioned without fail at the target surface (104). Moreover, the dual steering sheath according to the present disclosure in turn allows for optimal three-dimensional positioning of the medical device, e.g. a replacement heart valve, as well as sufficient space for easy release and deployment. [Figure 6]5 illustrates a prior art embodiment of a one-way steerable sheath. The limitations of positioning with a one-way sheath are illustrated. (i) centering of the delivery system (102) within the implantation site (104), (ii) perpendicular orientation (90°) to the implantation site, and (iii) a predefined distance (indicated by an "X" in FIG. 5 ) between the distal end of the steerable sheath (101) and the implantation site (104) are important to ensure unhindered deployment of the medical device or implant (103). The lower sheath (101) in the image, including the catheter (102), is centered within the implantation site. However, the distal end of the sheath (101) is exactly at the implantation site, so the medical device (103) will be deployed within the sheath (101), and therefore cannot be deployed without risk if it is not free to be released. Moving the sheath up facilitates the required distance between the distal end of the sheath (101) and the implantation site (104). However, it causes the delivery system (102) to lose its central alignment within the implantation site (104). Further actuation of the bend (not shown in the image) may allow the delivery system to cross through the center of the implantation site, but not at a 90° angle. [Figure 7]FIG. 1 illustrates a preferred embodiment of a dual steerable sheath (upper sheath) according to the present disclosure compared to a one-way sheath (lower sheath) of the prior art. This figure shows a direct comparison between the one-way sheath (101) and the S-shaped steering sheath (105). The one-way sheath (101) can achieve a central positioning within the implantation site. However, due to its bending over its entire length (as described above with respect to the prior art), the distal end of the sheath terminates at the plane of the implantation site. This causes the catheter (102) to not completely leave the distal portion of the sheath (101), and therefore the implant will be deployed within the sheath (101) since the capsule carrying the medical device (103) is still at least partially within the sheath (101). In contrast, the S-shaped steering sheath (105) can achieve a central and vertical alignment with respect to the implantation site (104) or implantation surface, as well as maintain the required distance between its distal end and the implantation site (104), allowing for easier release and improved deployment. [Figure 8]FIG. 1 illustrates a preferred embodiment of a dual steerable sheath (upper sheath) according to the present disclosure, compared to a one-way sheath (lower sheath) of the prior art. This figure shows a single bend sheath (101) that, due to a slight bend along its length, terminates at its distal end at the target point, e.g., the implantation site or surface (104), rather than 20 mm above the annulus when targeting a heart valve. Even though this position is perpendicular and centered to the implantation site (104), the implant (103) is now too low to be deployed. Note that to achieve optimal deployment, the implantation surface (dashed line 104) needs to be in the center of the prosthesis. On a practical level, when the catheter (102) is retracted so that the center of the implant is aligned with the target surface (104) intended for the target, the prosthesis is still at least partially covered by the sheath and cannot be released or deployed. Only by using the dual steering sheath (105) according to the present disclosure can the ends of the steering sheath (105) be positioned at the correct distance with sufficient space to position the catheter (not shown) having a capsule carrying the medical device to be deployed in the proper plane (104) and provide sufficient space to release and deploy the implant. [Figure 9] FIG. 1 illustrates a preferred embodiment of a dual steerable sheath (105) according to the present disclosure compared to a prior art one-way sheath (101). The figure shows that the prior art single bending sheath (101) can be moved up to achieve a distance of 20 mm to the annulus / implantation site / surface (104). However, by doing so, the implant (103) is off-center as the effect of bending over the entire length of the sheath becomes more evident. In contrast, the dual steerable sheath (105) advantageously allows free release and error-free positioning and deployment of the medical device (103) (not shown here) since it can be centered and kept at the required distance to the implantation surface (104). [Figure 10]9 illustrates a preferred embodiment of a dual steerable sheath (105) according to the present disclosure in comparison to a prior art one-way sheath (101). Based on the previous FIG. 9, further actuation of the prior art single bend sheath (101) could bring the prosthesis (103) to the center of the implantation site (104). However, at this point, the prosthesis (103) is not at a right angle (90°) to the implantation site. Thus, the prosthesis (103) cannot be deployed from the catheter (102) or, even if it could, would be deployed at an angle that would have a negative impact on its final positioning within the patient. [Figure 11a] 11a illustrates the attachment of a tension cable (110) at a tension ring (109) fixed in a steerable sheath (105) according to a preferred embodiment of the present disclosure, in which FIG. 11a depicts a tension ring (109) that presents two adjacent holes twice in different parts of the tension ring, one representing the steering point. The cable is inserted into one hole from the proximal side of the tension ring and then looped into the other hole from the distal side of the tension ring, thus creating a double cable in the pulling direction without the need for a fixing means on the tension ring. The tension cable attached to the distal tension ring can pass through the two unused holes on the proximal tension ring. In an alternative embodiment, the tension ring, or at least the proximal tension ring, can be designed as, for example, a 330° ring with two holes in one location and an opening in a second location, advantageously allowing a distal tension cable / wire attached to the distal steering point to pass through without interfering with the proximal tension ring and providing sufficient space for the distal tension cable / wire. However, the tension ring can also be designed as, for example, 270°, or variations between 270° and 330°, for example, 290°, 300°, 310°. [Figure 11b]11a and 11b illustrate the attachment of a tensioning cable (110) to a tensioning ring (109) fixed within a steerable sheath (105) according to a preferred embodiment of the present disclosure, with FIG. 11b depicting a tensioning ring (109) exhibiting two lumens containing tensioning cables (110) that are positioned in opposite directions through the lumens to serve as attachments for pulling the tensioning ring (109) and therefore the steerable sheath in each direction. [Figure 12] FIG. 1 illustrates a preferred embodiment of the present disclosure and the use of different materials (25D, 40D, 72D, Gr) that can be altered to achieve specific bending characteristics in a steerable sheath (S-shaped sheath) that can be tailored to specific bending requirements as desired. Proximal Grilamid® is used because it is a relatively stiff material. Further distally, in defined areas, different stiffnesses of Pebax® are used. 72D, 40D and 25D refer to different stiffness materials, where the material is selected to be increasingly softer in the distal direction. Thus, a polymer jacket is formed and used, including reinforcements that are selected depending on the bending requirements of the device, i.e., bend radius and bend angle. Included distally is a laser cut hypotube (115). Each direction of the S-shaped sheath (105) indicates its specific hypotube depending on the intended bending direction. Distal to each hypotube is a pull ring (109, 111) for connecting a pull wire. The proximal portion of the steerable sheath exhibits braiding. An internal PTFE liner can be added to reduce friction when connecting and manipulating the catheter. [Figure 13]FIG. 1 illustrates two hypotubes and material aspects of a preferred embodiment of the present disclosure. In this case, the cut in one or more hypotubes is at a 180° angle, which allows for a direct counterbend. The cut can be made in one or two hypotubes, which can be joined by, for example, a polymer jacket. The tension rings (distal 109; proximal 111) and respective tension cables (110; 112) are shown. [Figure 14] FIG. 1 illustrates a preferred embodiment hypotube (115) of the present disclosure. Shown is a distal pull ring (109) and a pull wire or cable (110) that runs inside the hypotube (115). [Figure 15a] 15a-c show different bending states of a steerable sheath according to a preferred embodiment of the present disclosure; in FIG. 15a, only the distal bending mechanism is operated, thereby resulting in only distal bending, but the proximal portion also bends as a secondary effect leading to rightward bending in places. [Figure 15b] 15A-15C illustrate different bending states of a steerable sheath in accordance with a preferred embodiment of the present disclosure; in FIG. 15b, the proximal cables are also pulled to some extent to create a partial counterbend. [Figure 15c] 15c shows different bends of the steerable sheath according to a preferred embodiment of the present disclosure, where further pulling with the proximal pull cable can achieve an S-curve (FIG. 15c). The distal portion of the sheath can also be actuated and bent as it can be further pulled by the distal pull cable (110) through the distal pull ring (109) (not shown). [Figure 16] FIG. 1 depicts a preferred embodiment having aspects of a steerable sheath according to the present disclosure connected to a handle having at least two or two actuators (113, 114). These actuators are used to operate the dual steering of the steering sheath. Different materials (25D, 40D, 72D, Gr) and pull rings (109, 111) are represented. [Figure 17] 1 depicts a distal tension ring (109) and a proximal tension ring (111) and a cable (110) of the distal tension ring and a cable (112) of the proximal tension ring, with the cable (110) passing through the open space of the tension ring (111), with the advantage that no additional space is required in the diameter and interference of the cable or wire with the proximal tension ring (111) is avoided. [Figure 18] 17 depicts a hidden edge visualization drawing of the tension ring (109 / 111) of FIG. 17 showing two holes at one location for the attachment of a tension cable and an open space (116) in the tension ring (109 / 111) for passing any cables or wires from distal to proximal, and possibly through the handle of the device, without interference with said tension ring (111).

[0024] Detailed Description In the following description, certain terms of the present disclosure will be defined. Otherwise, technical terms in the context of the present disclosure shall be understood by those of ordinary skill in the relevant art.

[0025] The term "prosthesis" or "medical device" or "implant" in the sense of this disclosure should be understood as any medical device that can be delivered minimally invasively. These terms can be used interchangeably. The prosthesis or medical device or implant can be a stent or a stent-based prosthesis or a stent-based replacement heart valve, such as an aortic, mitral or tricuspid heart valve.

[0026] The term "catheter" or "delivery device" in the sense of the present disclosure should be understood as a device used to deploy a prosthesis at a given site within a patient, for example to replace a heart valve, such as the aortic, mitral or tricuspid heart valve.

[0027] "S-sheath" or "S-shaped sheath" or "steerable sheath" or "dual steerable sheath" or "S-shaped steering sheath" or "S-shaped steerable sheath" or "dual steerable sheath" specifically refers to a steerable sheath that is actuated at at least two points, e.g., two points or two steering points, to achieve specific and directed essentially precise positioning of a replacement medical device. These terms can be used interchangeably. There may also be multiple steering points, e.g., three or four steering points, and thus can be described as a "multiple steerable sheath."

[0028] The term "pulling means" or "pulling wire" or "pulling cable" in the sense of the present disclosure should be understood as any means or part useful for exerting a pulling force, such as for example a wire or cable.

[0029] The term "loading" within the meaning of this disclosure should be understood as positioning the prosthesis in the catheter so that the catheter is ready to begin the delivery and deployment process into the patient.

[0030] The term "useful materials" in the sense of the present disclosure should be understood as any materials that are compatible with each other, can optionally be sterilized, and / or are low-friction materials.

[0031] An "elongate sheath" in the sense of this disclosure is a tube that is biocompatible in the sense that it can be made of different materials and used in medical devices. The sheath can be constructed from a combination of materials that provide the desired stiffness and / or flexibility, as commonly applied in catheter technology and known to those skilled in the art.

[0032] An "actuator" in the sense of this disclosure is a means that allows the manipulation of a distal part from the actuator, for example the actuator is proximal and located in the handle, the part to be manipulated is distal and a means, for example a pull wire, connects the two parts. One actuator can be designed to actuate two parts simultaneously or sequentially or independently of each other. Alternatively, two actuators can each actuate one distal part cooperatively or the two actuators can be linked to actuate multiple distal parts simultaneously or sequentially.

[0033] A "steering point" in the sense of the present disclosure is a target point of a means for connecting an actuator to a distal portion intended to be manipulated. A desired steering point can be fitted with, for example, a pull ring connected to a pull wire which is in turn actuated by an actuator. A steering sheath according to the present disclosure can be provided with two, three or four steering points, which can be positioned according to the desired double bending of the sheath. For example, the steering points can be spaced apart and they can be positioned at a certain angle to each other on the sheath, for example 180° or 90°. If the steerable sheath includes two or three steering points, these steering points can be actuated independently, sequentially or simultaneously by one or two actuators.

[0034] "Unwanted secondary bending" in the sense of this disclosure is the movement of a sheath or catheter that actively flexes in one direction, resulting in bending of other parts of the sheath or catheter due to that flexing and due to the flexibility of the sheath and / or catheter. Although such secondary bending is usually undesirable, it occurs due to material properties and adversely affects the positioning process and accuracy.

[0035] An "actuator" in the sense of the present disclosure is a means connected to a pull ring, for example by a pull wire, and serves to manipulate the pull ring, for example by applying tension to the pull wire connected to the pull ring, in order to bend the steering sheath in a given direction. One actuator can manipulate one pull ring, and the steering sheath can include a handle with one, two or more actuators, and one actuator can be designed to manipulate one pull ring independently, for example via a pull wire, or one actuator can be designed to manipulate two pull rings and counter-manipulate, for example, two pull rings, for example by pull wires, one of which is independently connected to one pull ring (i.e. at the steering point). The actuator serves to manipulate the steering sheath so that the distal tip is directed to a certain target point on a certain target surface within the target area.

[0036] "Counter-actuation" in the sense of this disclosure relates to a coordinated bending of the steerable sheath, e.g., depending on the placement of the pull rings and the location of the connections to, e.g., pull wires, resulting in bending and counter-bending. For example, if two pull ring connection points with pull wires are positioned at 180° and there is longitudinal space on the steerable sheath, the counter-bending or counter-actuation depicted in FIG. 15c creates an S-curve of the sheath.

[0037] A "target area" within the meaning of this disclosure is the three-dimensional space surrounding or within a native organ, such as a native heart valve, which may be, for example, a tricuspid heart valve.

[0038] A "target surface" in the sense of the present disclosure is a two-dimensional surface toward which a certain portion of either the steering sheath itself or a distal catheter portion, e.g., a capsule carrying a medical device, e.g., a heart valve prosthesis, is intended to be directed by the steering sheath. This "target surface" may be the annulus surface of a native heart valve.

[0039] A "target point" in the sense of this disclosure is a precise point on a target surface at which a particular portion of the catheter and a particular region of the distal portion of the catheter, such as a capsule carrying a medical device, is reached. This "target point" may in certain cases be the point at which the distal end of a steerable sheath is reached.

[0040] A "bend point" within the meaning of this disclosure is a point within the sheath that bends in response to multiple materials and the laser cut hypotube, which may be defined accordingly by the polymer jacket and laser cut pattern, or the material may be any useful material for the purposes of this disclosure, such as any type of reinforcement, such as braiding with different PPI or coils exhibiting different material properties.

[0041] In one aspect, the problem underlying the present application is solved by a steerable sheath comprising an elongated sheath, at least one actuator, at least two different sheath steering points, and means for connecting said at least one actuator to said two different sheath steering points. The steering sheath may also be described as a dual steerable sheath.

[0042] The present invention advantageously achieves positioning of a defined point or region of a steering sheath or / and a defined point or region of a distal portion of a catheter introduced through the steering sheath to a target point in a target region within a patient. Thus, by using a steering sheath according to the present disclosure, it becomes possible to deploy a medical device, such as a heart valve prosthesis, such as a tricuspid heart valve prosthesis, very precisely in three-dimensional space, thus achieving optimal deployment of said medical device within the patient.

[0043] It is therefore possible to precisely orient a certain face or point of a medical device, such as a replacement heart valve, to a certain face of a target site, thereby enabling, for example, the replacement heart valve leaflets fixed to the replacement prosthesis to be aligned with the valve annulus and / or with the leaflets of the native heart valve.

[0044] A steering sheath according to the current disclosure at least partially or essentially completely avoids the disadvantages of known deployment systems for minimally invasive deployment of medical devices.

[0045] The steering sheath according to the current disclosure can be advantageously actuated in various three-dimensional directions within a three-dimensional target region, thus allowing the distal sheath and distal catheter portion carrying the medical device to be manipulated with respect to a desired location, plane and angle relative to the target site, thereby allowing the deployment of the medical device to be achieved in optimal alignment with its target surface, e.g., a natural organ such as a heart valve and a valve annulus, thereby enabling optimal deployment.

[0046] The present invention advantageously achieves positioning of a distal portion of a sheath, or of a catheter pushed distally into a sheath, to a target point in various planes and within a three-dimensional region of a target area. Thus, the present invention allows the distal portion of the sheath or catheter to be essentially directed in three dimensions within a target area. The advantages described with respect to three-dimensional positioning are evident, for example, from Figures 5-10 and 15.

[0047] The distal portion may be actuated by known means, which may be connected to a proximal handle. In a preferred embodiment, the steerable sheath may be connected to at least one actuator, for example, one or more actuators may be part of the handle for easier manipulation. A steerable sheath according to the present disclosure may comprise two, three or four actuators, preferably one actuator independently connected to one sheath steering point, or two independent actuators independently actuating two steering points.

[0048] A steerable sheath according to the present disclosure can be combined with a proximal handle, with the actuator being combined with the proximal handle.

[0049] The handle can be equipped with actuators and mechanisms known to those skilled in the art, such as screws and levers, for actuating pull wires or any other known useful pulling mechanism. The steerable sheath according to the present disclosure can exhibit a useful number of steering points for actuating the sheath independently or simultaneously or sequentially in at least two directions, as desired, with at least two sheath steering points located distally. The steering point locations are selected to achieve bidirectional bending, which are essentially counter bending to each other to compensate for undesired secondary bending. Additionally, the inventive concept of at least two steering points allows for precise actuation of the distal portion of the sheath within a target region in three-dimensional space.

[0050] The steerable sheath according to preferred aspects of the present disclosure may be constructed from one or more materials. Multiple materials may be combined to advantageously assist in the desired bending and counter bending of the sheath. The elongated sheath may be made from materials selected from biocompatible materials, polytetrafluoroethylene (PTFE), polymers with different durometers, stainless steel, Nitinol, PEBAX®, and / or polyamides, such as Grilamid®, or may comprise combinations thereof.

[0051] A combination of softer and harder materials may be used to support the desired function of deflecting the sheath and the catheter contained therein. A steerable sheath according to the present disclosure may be designed such that a softer material is used at the distal end of the sheath and a harder material, preferably stainless steel, PEBAX®, preferably Grilamid®, is used proximally of the sheath.

[0052] In a particular embodiment according to the present disclosure, the invention relates to a steerable sheath with two actuators, two steering sheath points, and two means for independently connecting each actuator to one of the sheath steering points.

[0053] A steerable sheath according to the present disclosure can use any means compatible with other parts and components to actuate and manipulate the distal steering point, such means for connecting being, for example, a wire, e.g., a flat wire, a round wire, a cable, a filament, or a fabric.

[0054] Each steering point can be connected to one actuator, preferably two, three or four actuators, i.e., each steering point can be connected to an actuator in a different way, and by pulling each steering point, the steerable sheath can be actuated in various directions or combinations of directions, using two, three or four steering points as is useful for manipulating the sheath, and thus directing a defined point on the steering sheath and / or the catheter contained therein to a desired target point. Steerable sheaths according to the present disclosure can include a means for connecting that can be pulled proximally by one or more actuators.

[0055] As discussed above, the steering points can be advantageously positioned to achieve a particular deflection. A steerable sheath according to the present disclosure can include at least two, and up to several, steering points, where the at least two different sheath steering points are spaced apart circumferentially or / and longitudinally along the sheath.

[0056] In certain embodiments of the present disclosure, the steerable sheath may comprise or exhibit two, three, or four sheath steering points, preferably two sheath steering points.

[0057] It may be advantageous to design a particular pattern of steering points into the steerable sheath. A steerable sheath according to the present disclosure may have at least two or two different sheath steering points, the steering points being spaced apart by angles of 10°, 20°, 30°, 45°, 90°, 120°, 140°, 160°, or 180°.

[0058] Additionally, in a steerable sheath according to the present disclosure, at least two or two different sheath steering points are spaced apart by a distance of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 cm, which spacing can be combined with angular, circumferential or longitudinal distances as described above.

[0059] Thus, a preferred embodiment of the present disclosure is a steerable sheath in which the at least two different sheath steering points are spaced apart by a combination of an angle of 180° and a distance of about 15-40 cm, more preferably 15-20 cm.

[0060] It has been shown to be advantageous if the steerable sheath according to the present disclosure exhibits two different sheath steering points positioned at an angle of 180° or at an angle of 180° and spaced 5-10 cm apart, preferably 7 cm or 8 cm apart.

[0061] The steering points during actuation move in unison. A steerable sheath according to the present disclosure is characterized in that the two different sheath steering points are counter-actingly movable by the two actuators.

[0062] It has proven to be very advantageous to design the steerable sheath according to the present disclosure such that two counter-acting actuators allow reaching various target points, preferably in one horizontal plane, or one target point, by adjusting the bending of both of the two actuators.

[0063] In one aspect, the problem underlying the present application is solved by a catheter system for deployment of a medical device, such as a replacement heart valve, comprising a steerable sheath according to the present disclosure. It may be possible to incorporate the steerable sheath into the catheter shaft or to incorporate the sheath steering points into the catheter outer shaft.

[0064] The catheter includes all the components necessary for its operation, which are well known to those skilled in the art and need not be described in detail here.

[0065] The catheter portion carrying the medical device (distal, possibly within a capsule) must be pushed distally out of the distal end of the steerable sheath in order to be able to release the medical device, so that the portion carrying the medical device (e.g. a heart valve prosthesis loaded within a capsule) is positioned in the correct plane of the native valve.

[0066] The dual steerable sheath has dimensions in diameter and length to accommodate the prosthesis and other components, such as a catheter, suitable for manipulating the device and for effecting delivery and deployment of the prosthesis.

[0067] In one embodiment, the dual steerable sheath has an outer diameter of 40 French or less, preferably 30 or 20 French or less, or the outer diameter is 18 French. One advantage of the steerable sheath of the present disclosure is that it can achieve the function of reliable deployment of medical devices, such as heart valve prostheses.

[0068] It will be appreciated that the larger dimensions in diameter and length of a medical device that is to be manipulated and bent in different directions within a patient's vasculature present a challenge in that it requires greater forces to manipulate the medical device. Furthermore, the parts that are subject to pushing, pulling and bending forces must be able to withstand such increased forces. The larger the dimensions of the device, the greater the forces that are exerted on the components of the steerable sheath.

[0069] Moreover, in the disclosed devices which exhibit double bending or S-steering characteristics, forces acting in different or counter acting directions further exacerbate this problem.

[0070] It was therefore unexpected that the dual steering sheath of the present disclosure could be manipulated without any significant issues and that the system was capable of accomplishing the task and maneuverability of steering a medical device such as a heart valve prosthesis under increased force requirements in sizes up to 40 French.

[0071] Of particular advantage is that functionality is achieved in dual steering sheaths having outer diameters up to 40 French or up to 30 French. Such steerable sheaths of the present disclosure include a cable as a tensioning means, the tensioning cable being looped through a tensioning ring at the distal portion of the steerable sheath to form a tensioning means operated by an actuator located in the handle.

[0072] Such steerable sheaths according to the present disclosure are advantageously and surprisingly maneuverable and designed to maintain functionality for deployment of medical devices, such as heart valve prostheses, with all components designed and advantageously working together to be fully functional without significant quality issues or component failure.

[0073] In particular, the steerable sheath of the present disclosure accomplishes the task of reliable deployment of a medical device. In one embodiment, the steerable sheath includes a cable looped through one or more tension rings, and the sheath includes a hypotube for performing a predetermined bending direction. The components and combinations of components of the steerable sheath according to the present disclosure, such as the hypotube, also allow for a reduction in bending forces or forces required to direct the distal portion of the steerable sheath and / or the catheter contained therein. The steerable sheath and other components can advantageously withstand and support forces applied to the steerable sheath components associated with pulling and pushing actions, angular bending, positioning of the medical device at the target site, and stability of the sheath during deployment, and the steerable sheath components exhibit good reliability during use of the steerable sheath.

[0074] Thus, the selected combination of steering sheath components of the present disclosure achieves advantageous and reliable deployment of, for example, a heart valve prosthesis.

[0075] In one aspect, the problem underlying the present application is solved by a method for deployment of a heart valve prosthesis, in which a steerable sheath according to the present disclosure is used and predefined catheter points are actuated to predefined target points.

[0076] The method according to the current disclosure advantageously achieves positioning of the distal portion of the sheath, and therefore the introduced catheter, in various three-dimensional orientations within a three-dimensional target region. Thus, the distal sheath and distal catheter portion carrying the medical device can be manipulated with respect to a desired location, plane and angle relative to the target site. Thus, it allows deployment of the medical device to be achieved with optimal alignment with the native organ, e.g., the heart valve, and preferably the valve annulus or target surface, allowing optimal deployment.

[0077] In a method according to the present disclosure, the actuators are counter-actuated to reach different target points in a plane or in three-dimensional space by adjusting each actuator in a counter direction, as illustrated, for example, in Figure 15c.

[0078] In one aspect of the method according to the present disclosure, the sheath steering points can be actuated as needed to cause the distal portion of the steerable sheath or distal catheter portion to reach the desired target point for a correct and desired deployment and release position, and the actuators are counter actuated to essentially effect an S-shaped sheath or S-shaped steering sheath geometry.

[0079] In one aspect of the method according to the present disclosure, the target point can be targeted such that the prosthesis or medical device within the catheter is perpendicular to the implantation plane at the implantation site.

[0080] In one aspect of the method according to the present disclosure, the prosthesis or medical device to be deployed, e.g., a replacement heart valve, is deployed essentially in the center of the native annulus and / or essentially perpendicular to the plane of the native annulus.

[0081] In one aspect, the present disclosure relates to a method for the deployment of a heart valve prosthesis, in which the heart valve is deployed using a steerable sheath according to the present disclosure and / or a catheter system as described above or known to one of skill in the art.

[0082] Working Example The following describes preferred aspects of the present disclosure and should not be construed as limiting in any manner or manner. Moreover, those skilled in the art will understand that any of the above and below aspects and features of the present disclosure can be used and combined with any of the remaining features disclosed in the present disclosure. It should be understood that the present disclosure can combine any such feature with any other feature disclosed in the present disclosure without being bound or limited in any way with respect to the combination of features.

[0083] Example 1 In a preferred embodiment, the steerable sheath may comprise an outer portion of the sheath that comprises several polymers with different durometers. A higher durometer material is used proximally of the sheath, while the durometer of the material decreases closer to the distal end. The softer material at the distal end makes the sheath easier to bend. The sheath includes a PTFE liner on the inside, which reduces friction for the catheter traveling through the sheath. Between the PTFE liner and the polymer jacket, the reinforcing structure further influences the behavior of the sheath. Possible reinforcing materials are braids, coils and laser cut hypotubes. Common materials are metals, mostly stainless steel, but polymer monofilaments can also be used. The design of the reinforcing material determines the desired bend radius and bend angle in the distal section and generally the stiffness in each section. The distance between the two steering points is 15-90 mm, preferably 70 or 80 mm. [Explanation of symbols]

[0084] Material stiffness of 25D Pebax® (= Polyether-Block-Amide-Block-Copolymer = Thermoplastic Elastomer) Material stiffness of 40D Pebax® (= Polyether-Block-Amide-Block-Copolymer = Thermoplastic Elastomer) Material stiffness of 72D Pebax® (=Polyether-Block-Amide-Block-Copolymer = Thermoplastic Elastomer) 101 One-way sheath 102 Delivery Systems / Catheters 103 Implants / Prostheses 104 Implant Site 105 S-shaped sheath (double steerable sheath) 106 Target point at distal end of sheath (perpendicular to implantation site, distance X away) 107 Distal Bending 108 Proximal Bending 109 Distal Tension Ring 110 Distal tension ring cable 111 Proximal tension ring 112 Proximal tension ring cable 113 (first actuator that actuates the cable of the distal tension ring) 114 (a second actuator that actuates the cable of the proximal tension ring) 115 Laser cut hypotube 116 Tension ring opening Gr Grilamid (registered trademark) (= polyamide)

Claims

1. A long, thin sheath, At least two actuators; at least two different sheath steering points; means for connecting the at least two actuators to the two different sheath steering points; the actuator is coupled to a proximal handle, at least two different sheath steering points are spaced apart circumferentially and along the length of the sheath, the two different sheath steering points are counter-actingly movable by the two actuators, and the sheath includes at least two hypotubes having 180° angle cuts on opposite sides to be counter-bendable and dual-actuable; one of the two different steering points is located distal to the two hypotubes, and the other of the two different steering points is located between the two hypotubes; Each of the two different sheath steering points is formed by a tension ring fixed in the sheath, the tension ring having two sets of holes adjacent to each other in different parts, the means for connecting is formed by two cables attached to the tension ring by inserting the cables from the proximal side of the tension ring into one of the two holes and looping them from the distal side of the tension ring into the other hole, the cable attached to the set of two holes of the distal one of the two tension rings passes through the set of two holes not used in the proximal tension ring, and the two tension rings forming the two different sheath steering points have the same configuration. Steerable sheath.

2. The steerable sheath of claim 1 comprising two, three or four of said actuators.

3. The steerable sheath of claim 1 , wherein the at least two sheath steering points are distally located.

4. 2. The steerable sheath of claim 1, wherein the elongate sheath is made from a material selected from biocompatible materials, polytetrafluoroethylene (PTFE), polymers with different durometers, stainless steel, Nitinol, PEBAX®, and / or polyamides, such as Grilamid®, or a combination thereof.

5. The steerable sheath of claim 1 , wherein a softer material is used at a distal end of the sheath and a harder material is used at a proximal side of the sheath.

6. Two of the actuators; Two of said sheath steering points; 2. The steerable sheath of claim 1, further comprising: two means for connecting.

7. The steerable sheath of claim 1 , wherein the means for connecting is a wire, a cable, a filament, or a fabric.

8. The steerable sheath of claim 1 , wherein the means for connecting is capable of being pulled proximally by one or more of the actuators.

9. The steerable sheath of claim 1 comprising two, three, or four of said sheath steering points.

10. 2. The steerable sheath of claim 1, wherein two of the at least two different sheath steering points are spaced apart by an angle of 10°, 20°, 30°, 45°, 90°, 120°, 140°, 160°, or 180°.

11. 2. The steerable sheath of claim 1, wherein two of the at least two different sheath steering points are separated by a distance of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 cm.

12. The steerable sheath of claim 1 , wherein two of the at least two different sheath steering points are spaced apart by a combination of the angle of claim 10 and the distance of claim 11 .

13. 2. The steerable sheath of claim 1, wherein the two different sheath steering points are located at an angle of 180 degrees or at an angle of 180 degrees and a distance of 5-10 cm.

14. The steerable sheath of claim 1 , wherein the two counter-acting actuators allow reaching different target points in a horizontal plane by adjusting both bendings of the two actuators.

15. A catheter system for the deployment of a heart valve prosthesis comprising a steerable sheath according to any one of claims 1 to 14.

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