Improved Dilator

Abstract

The improved dilator (105) includes a dilator shaft (204) defining a lumen for receiving a functional device (e.g., a puncture device). The dilator shaft includes a proximal portion for manipulation by a user and a distal portion for placement in or near the heart. A dilator hub (202) is coupled to the proximal portion of the dilator shaft and includes a rotational coupling structure for coupling to a corresponding hub of a treatment sheath.

Description

[Technical field]

[0001] The present invention relates generally to methods and devices that can be used to provide therapy to a patient. More specifically, the present invention relates to systems and methods for delivering therapeutic devices to the heart. [Background technology]

[0002] Currently, devices exist for creating punctures, channels, or perforations in tissue within a patient's body. One such device is the Brockenbrough™ needle, which is commonly used to puncture the atrial septum of the heart. This device is a rigid, elongated needle that is adapted to be introduced into the patient's body via the femoral vein and directed toward the heart. This device relies on the use of mechanical force to pass a sharp tip through the septum. Alternatively, radiofrequency perforation devices have been developed whereby septal perforation is achieved by applying focused radiofrequency energy to the septal tissue via an electrode at the distal end of a relatively thin conductive probe.

[0003] Such drilling devices are often used in conjunction with a dilator to help support and guide the drilling device, and such dilators are often used in combination with a treatment sheath adapted to deliver treatment to the patient. Summary of the Invention

[0004] In Example 1, an enhanced dilator includes a dilator shaft defining a lumen for receiving a functional device (e.g., a puncture device) therethrough. The dilator shaft includes a proximal portion for manipulation by a user and a distal portion for placement in or near the heart. A dilator hub is coupled to the proximal portion of the dilator shaft and includes a rotational coupling structure for coupling to a corresponding hub of a treatment sheath, the rotational coupling structure preventing relative rotation between the dilator and the sheath.

[0005] Example 2 is the dilator of Example 1, and the sheath is a treatment sheath. Example 3 is the dilator of Example 1 or 2, and the puncture device is an RF puncture device or a mechanical needle.

[0006] Example 4 is the dilator of any of Examples 1 to 3, wherein the rotational coupling structure includes a protrusion adapted to mate with a recess in the sheath hub. Example 5 is the dilator of any of Examples 1-4, wherein the dilator hub includes an angled disengagement surface adapted to contact a mating surface on the sheath hub, the mating surface configured to generate an axial disengagement force on the disengagement surface.

[0007] Example 6 is the dilator of example 5, wherein the angled disengagement surface includes a first surface that is non-parallel to a second surface associated with the mating surface. Example 7 is the dilator of any one of Examples 1 to 6, wherein the shaft includes a reinforcing member.

[0008] Example 8 is the dilator of any of Examples 1-7, wherein the distal portion includes one or more radiopaque markers. Example 9 is the dilator of any of Examples 1-8, wherein the rotational coupling structure includes a first surface configured to contact a first surface of the recess disposed on the sheath hub.

[0009] Example 10 is the dilator of example 8, wherein the rotational coupling structure includes a second surface configured to contact a second surface of the recess disposed on the sheath hub. Example 11 is an improved dilator for coupling with a therapeutic sheath having a sheath hub. The improved dilator includes a dilator shaft defining a lumen for receiving a puncture device. The dilator shaft is structured to provide support for the puncture device when the puncture device is used to form a puncture in tissue. The dilator shaft includes a proximal portion and a distal portion and includes a dilator hub connected to the proximal portion. The dilator hub includes a resilient coupling system for coupling to the sheath hub.

[0010] Example 12 is the dilator of example 11, wherein the resilient coupling system includes a hexagonal distal end. Example 13 is the dilator of Examples 11 or 12, wherein the dilator shaft includes a reinforcing member for supporting the flexible puncture device.

[0011] Example 14 is the dilator of any of Examples 11 to 13, wherein the distal portion includes a radiopaque marker. Example 15 is the dilator of any of Examples 11-14, wherein the resilient coupling system includes a cylindrical body having an angled proximal end.

[0012] Example 16 is the dilator of any of Examples 11-15, wherein the resilient coupling system includes a plurality of circumferentially arranged protrusions. In Example 17, the system includes a dilator including a shaft defining a lumen adapted to receive and support a puncture device. The shaft includes a proximal portion for manipulation by a user and a distal portion for placement in or near the heart for manipulation by a user. A dilator hub is coupled to the proximal portion of the dilator shaft. The dilator hub includes a rotational coupling structure. The system includes a sheath having a sheath body defining a lumen adapted to receive the dilator. The sheath hub is coupled to the proximal portion of the sheath body. The sheath hub includes a recess for coupling with the rotational coupling structure to inhibit relative rotation between the dilator and the sheath.

[0013] Example 18 is the system of example 17, wherein the rotational coupling structure includes one or more resilient members. Example 19 is the system of examples 17 or 18, wherein the recess includes a generally rectangular shape surrounding a lumen adapted to receive a dilator.

[0014] Example 20 is the system of any of Examples 17-19, wherein the rotational coupling structure includes a first surface configured to contact a first inner portion of the recess and a second surface configured to contact a second inner portion of the recess.

[0015] While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. [Brief description of the drawings]

[0016] [Figure 1A] 1 is a schematic diagram of a medical procedure within a patient's heart utilizing a transseptal access system in accordance with an embodiment of the present invention. [Figure 1B] 1 is a schematic diagram of a medical procedure within a patient's heart utilizing a transseptal access system in accordance with an embodiment of the present invention. [Figure 1C] 1 is a schematic diagram of a medical procedure within a patient's heart utilizing a transseptal access system in accordance with an embodiment of the present invention. [Figure 2A] FIG. 2 is a perspective view of a dilator and a sheath according to an embodiment of the present invention. [Figure 2B] FIG. 2 is a perspective view of a dilator and a sheath according to an embodiment of the present invention. [Figure 2C] FIG. 2 is a perspective view of a dilator and a sheath according to an embodiment of the present invention. [Figure 2D] FIG. 2 is a perspective view of a dilator and a sheath according to an embodiment of the present invention. [Diagram 3] FIG. 1 illustrates an improved dilator according to one embodiment of the present invention. [Figure 4A]1A-1C show a transseptal assembly with an improved dilator according to one embodiment of the present invention. [Figure 4B] 1A-1C show a transseptal assembly with an improved dilator according to one embodiment of the present invention. [Figure 4C] FIG. 1 illustrates an improved dilator according to one embodiment of the present invention. [Figure 5A-5C] 13A-13C show an improved dilator according to an additional alternative embodiment of the present invention. [Figures 6A-6C] FIG. 1 illustrates a resilient connection system according to one embodiment of the present invention. [Figure 7A-7B] 1 illustrates a sheath hub and an improved dilator being inserted into the sheath hub in accordance with an embodiment of the present invention. [Figure 8] 13A-13C illustrate a resilient coupling system disposed within a sheath hub, according to one embodiment of the present invention. [Figure 9] 1 shows a dilator hub of an improved dilator according to one embodiment of the present invention. [Figure 10] 1 illustrates a method for performing a therapeutic termination procedure in the left atrium of a patient. [Figure 11] 1 illustrates a method of using an improved workflow when performing a therapy termination procedure in a patient's left atrium. [Figure 12A-12B] FIG. 13 is a perspective view of a dilator inserted into a sheath and a dilator hub engaging a sheath hub in accordance with an embodiment of the present invention. [Figure 13A-13B] FIG. 13A is a perspective view of a sheath hub and FIG. 13B is a top view of a portion of a dilator hub that mates with the sheath hub, in accordance with an embodiment of the present invention. [Figure 14A-14B] FIG. 14A is a cross-sectional view of a dilator hub mating with a sheath hub, and FIG. 14B is a perspective view of the dilator hub, in accordance with an embodiment of the present invention. [Figure 15A-15B] FIG. 15A is a perspective view of a dilator hub and FIG. 15B is a cross-sectional view of the dilator hub mating with a sheath hub in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. However, the invention is not limited to the described embodiments. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

[0018] 1A-1C are schematic diagrams of a medical procedure 10 within a patient's heart 20 utilizing a transseptal access system 50 in accordance with an embodiment of the present disclosure. As is known, the human heart 20 has four chambers: a right atrium 55, a left atrium 60, a right ventricle 65, and a left ventricle 70. Separating the right atrium 55 from the left atrium 60 is an interatrial septum 75, and separating the right ventricle 65 from the left ventricle 70 is an interventricular septum 80. As is further known, deoxygenated blood from the patient's body is returned to the right atrium 55 via an inferior vena cava (IVC) 85 or a superior vena cava (SVC) 90.

[0019] A variety of medical procedures have been developed to diagnose or treat physiological disorders occurring within the left atrium 60 and associated structures. Exemplary such procedures include, but are not limited to, placement of a diagnostic or mapping catheter within the left atrium 60 for use in generating an electroanatomical map or diagnostic image thereof. Other exemplary procedures include endocardial catheter-based ablation (e.g., radiofrequency ablation, pulsed field ablation, cryoablation, laser ablation, radiofrequency ultrasound ablation, etc.) of target sites within the heart chambers or adjacent blood vessels (e.g., pulmonary veins and their ostia) to terminate cardiac arrhythmias such as atrial fibrillation and atrial flutter. Still other exemplary procedures may include placement of a left atrial appendage (LAA) closure device. Of course, the foregoing examples of procedures within the left atrium 60 are merely illustrative and in no way limiting with respect to the present disclosure.

[0020] The medical procedure 10 shown in FIGS. 1A-1C is an exemplary embodiment for providing access to the left atrium 60 using a transseptal access system 50 for subsequent placement of the aforementioned diagnostic and / or therapeutic devices therein. As shown in FIGS. 1A-1C, the target tissue site may be defined by tissue on the atrial septum 75. In the illustrated embodiment, the target site is accessed via the IVC 85, e.g., through the femoral vein, in accordance with conventional catheter insertion techniques. In other embodiments, access to the target site on the atrial septum 75 may be achieved using a superior approach of advancing the transseptal access system 50 via the SVC 90 into the right atrium 55.

[0021] In the illustrated embodiment, the transseptal access system 50 includes an introducer sheath 100, a dilator 105 having a dilator body 107 and a tapered distal tip portion 108, and a piercing device (e.g., a radio frequency (RF) piercing device) 110 having a distal end portion 112 terminating in a tip electrode 115. As illustrated, in the assembled use state shown in FIGS. 1A-1C, the RF piercing device 110 may be disposed within the dilator 105, which itself may be disposed within the sheath 100. In one embodiment where the transseptal access system 50 is disposed within the right atrium 55 via the IVC 105, the user introduces a guidewire (not shown) into the femoral vein, typically the right femoral vein, and advances it towards the heart 20. The sheath 100 is then introduced over the guidewire into the femoral vein and advanced towards the heart 20. In one embodiment, the distal end of the guidewire and sheath 100 are then disposed within the SVC 90. These steps may be performed with the aid of an imaging system (e.g., fluoroscopy or ultrasound imaging). The dilator 105 is then introduced into the sheath 100 and over the guidewire and advanced through the sheath 100 and into the SVC 90. Alternatively, the dilator 105 may be fully inserted into the sheath 100 before entering the body and both advanced simultaneously towards the heart 20. Once the guidewire, sheath 100 and dilator 105 are positioned within the SVC 90, the guidewire is removed from the body and the sheath 100 and dilator 105 are retracted such that their distal ends are positioned within the right atrium 55. The RF perforation device 110 described above is then introduced into the dilator 105 and advanced towards the heart 20.

[0022] The user then positions the distal end of the dilator 105 against the atrial septum 75, which may be done under imaging guidance. The RF perforation device 110 is then positioned so that the electrode 115 is aligned with or slightly protrudes from the distal end of the dilator 105. The dilator 105 and the RF perforation device 110 are dragged along the atrial septum 75, for example, positioned against the fossa ovalis of the atrial septum 75 under imaging guidance. Various additional steps may be performed, such as measuring one or more characteristics of the target site, for example, electrogram or ECG (electrocardiogram) tracing and / or pressure measurement, or delivering a substance to the target site, for example, delivering a contrast agent. Such steps may facilitate localization of the tip electrode 115 at the desired target site. In addition, tactile feedback provided by the medical RF perforation device 110 may be used to facilitate positioning of the tip electrode 115 at the desired target site.

[0023] With the tip electrode 115 and dilator 105 positioned at the target site, energy is delivered from an energy source (e.g., an RF generator) through the RF perforation device 110 to the tip electrode 115 and the target site. In some embodiments, the energy is delivered at a power of at least about 5 W at a voltage of at least about 75 V (peak-to-peak) and serves to vaporize cells in the vicinity of the tip electrode 115, thereby forming a void or perforation through the tissue at the target site. The user then applies a force to the RF perforation device 110 to advance the tip electrode 115 at least partially through the perforation. In these embodiments, the delivery of energy is stopped when the tip electrode 115 has passed through the target tissue, i.e., reached the left atrium 60. In some embodiments, the step of delivering energy occurs for a period of about 1 second to about 5 seconds.

[0024] With the tip electrode 115 of the RF perforation device 110 crossing the atrial septum 75, the dilator 105 can be advanced forward, with the tapered distal tip portion 108 operating to gradually enlarge the perforation so that the distal end of the sheath 100 can be advanced into the left atrium 60.

[0025] In some embodiments, the distal end portion 112 of the RF perforation device 110 may be preformed to assume an atraumatic shape, such as a J-shape (as shown in FIGS. 1B-1C), a pigtail shape, or other shape selected to direct the tip electrode 115 away from the endocardial surface of the left atrium 60. Examples of such RF perforation devices may be found, for example, in U.S. Patent Application No. 16 / 445,790 and U.S. Patent Application No. 16 / 346,404, both of which are assigned to Baylis Medical Company, Inc. The aforementioned preformed shapes may advantageously function to minimize the risk of unintended contact between the tip electrode 115 and tissue within the left atrium 60, and may also operate to anchor the distal end portion 112 within the left atrium 60 during subsequent procedural steps. For example, in embodiments, the RF perforation device 110 may be structurally configured to function as a delivery rail for placement of a relatively large inner diameter therapeutic delivery sheath and associated dilator(s). In such embodiments, the dilator 105 and sheath 100 are withdrawn following placement of the distal end portion 112 of the RF perforation device 110 into the left atrium 60. The anchoring feature of the preformed distal end portion 112 inhibits unintentional retraction of the distal end portion 112 and corresponding loss of access to the perforation site on the atrial septum 75 during such withdrawal.

[0026] A variety of medical procedures have been developed to diagnose or treat physiological disorders occurring within the left atrium 60 and associated structures. Exemplary such procedures include, but are not limited to, placement of a diagnostic or mapping catheter within the left atrium 60 for use in generating an electroanatomical map or diagnostic image thereof. Other exemplary procedures include endocardial catheter-based ablation (e.g., radiofrequency ablation, pulsed field ablation, cryoablation, laser ablation, radiofrequency ultrasound ablation, etc.) of target sites within the heart chambers or adjacent blood vessels (e.g., pulmonary veins and their ostia) to terminate cardiac arrhythmias such as atrial fibrillation and atrial flutter. Still other exemplary procedures may include placement of a left atrial appendage (LAA) closure device. Of course, the foregoing examples of procedures within the left atrium 60 are merely illustrative and in no way limiting with respect to the present disclosure.

[0027] In some embodiments, catheters, therapeutic devices, and sheaths may be deployed through the sheath 100 after the sheath 100 is successfully deployed into the desired heart chamber (e.g., the left atrium). In other embodiments, the therapeutic device (e.g., mapping catheter, therapeutic sheath, medical device, etc.) is part of the sheath 100 and forms the therapeutic sheath.

[0028] 2A-2B are perspective views of a dilator and sheath according to some embodiments of the present disclosure. As shown, the dilator 105 is partially inserted into the lumen of the sheath 100. The dilator 105 includes a handle 201, a dilator hub 202, and a dilator shaft 204. The sheath 100 includes a sheath hub 206 and a sheath body 208.

[0029] The releasable coupling mechanism 300 is configured to releasably couple two corresponding members, such as a first mating member 101 associated with a sheath hub 206 and a second mating member 200 associated with a dilator hub 202. Specifically, the releasable coupling system comprises a coupling mechanism 300 including a coupling member 1000, a first mating member 101, and a second mating member 200 receivable by the first mating member 101 (e.g., through an opening 113) to be coupled to the first mating member 101 by the coupling member 1000. In conventional systems, the coupling member 1000 is configured to couple corresponding first and second mating members having specified materials and dimensions to each other. In such cases, each of the first and second mating members is designed to accommodate the other member. For example, a conventional sheath hub is designed for a corresponding dilator hub, and the dimensions and material selection are optimized for the corresponding dilator hub. Additionally, the dimensions and material selection of the dilator hub are optimized for the corresponding sheath hub.

[0030] 3 illustrates one embodiment of the dilator 105, also referred to as an improved dilator 105, configured to support a crossing device and configured to removably couple to a sheath 100, such as a treatment sheath. The improved dilator 105 includes a dilator hub 202 that includes a resilient coupling system 229.

[0031] In some embodiments, as shown in FIGS. 4A and 4B, the improved dilator 105 is configured to support a flexible puncture or punch device 110. In some embodiments, the flexible puncture or punch device 110 is a radiofrequency (RF) wire having a distal electrode 115 (FIG. 4A). In some embodiments, the RF wire is a 0.035 inch (0.889 mm) wire. In some such examples, the RF wire includes a J-tip wire, or in the alternative, the RF wire includes a pigtail wire. In other embodiments, the flexible puncture or punch device 110 is a mechanical puncture wire including a sharpened distal tip 116 (FIG. 4B). Additionally, it should be understood that the distal end of the improved dilator 105 may include a variety of tips and configurations without departing from the intended scope of the present invention.

[0032] In an embodiment in which the improved dilator 105 is configured to support a flexible puncture or perforation device 110, the improved dilator 105 includes a reinforcing member 34, such as a stainless steel hypotube, extending longitudinally within one or more polymer layers. In one example, the reinforcing member 34 is disposed within the polymer layers 35, 37, as shown in FIG. 4C. Thus, the reinforcing member 34 defines an inner lumen of the dilator 105. In another example, the reinforcing member 34 is substantially covered by one or more polymer layers 35, 37 such that the reinforcing member 34 is disposed between the inner polymer layer 35 and the outer polymer layer 37. In other words, the reinforcing member 34 (e.g., a stainless steel hypotube) is sandwiched or disposed between two polymer layers. In some such examples, the inner polymer layer 35 and the outer polymer layer 37 are made of high density polyethylene (HDPE). In alternative embodiments, the outer layer 37 may be made of Pebax®, low density polyethylene (LDPE), or medium density polyethylene (MDPE).

[0033] In some such embodiments, the improved dilator 105 provides sufficient stiffness to the puncture device 110, such as an RF wire, to allow for sufficient force transmission to allow for force transmission from the proximal end to the distal end of the assembly. Thus, the improved dilator provides sufficient stiffness to the puncture device to allow torque applied by a user to be transmitted to the distal end of the assembly.

[0034] In some such examples, the reinforcing member 34 provides sufficient rigidity to the improved dilator to allow for sufficient force transmission to allow for force transmission from the proximal end to the distal end of the assembly 50. More specifically, the reinforcing member 34 provides sufficient rigidity to the assembly 50 such that the substantially flexible puncture or punch device 110 (such as an RF wire) together with the dilator 105 can transmit sufficient force to allow a force applied by a user to be transmitted to the distal end of the assembly 50 (thus allowing for force transmission to the distal end of the substantially flexible puncture or punch device 110).

[0035] The reinforcing member 34 can thus provide the substantially flexible RF wire with force transmission capabilities, such that when the RF wire is used with the improved dilator 105, for example, a force applied by a user can be transmitted to the distal end of the assembly 50 to act on tissue at a target tissue site. In this manner, the reinforcing member 34 functions as a force transmission portion of the assembly 50. Additionally, the reinforcing member 34 provides sufficient stiffness to allow torque to be transmitted to the distal end of the assembly 50. Thus, the reinforcing member 34 provides sufficient stiffness to the assembly as a whole, and the substantially flexible puncture or punch device 110, together with the improved dilator 105, provide sufficient stiffness to the assembly 50 to allow torque applied by a user to be transmitted to the distal end of the assembly 50 (and thus allow torque to be transmitted to the distal end of the substantially flexible puncture or punch device 110).

[0036] In some embodiments of the present invention, the force transfer portion of the assembly 50 has a force of at least about 0.0085 Nm 2 , for example, about 0.0115 Nm 2 In some embodiments of the invention, the force transfer portion of the assembly has a bending stiffness of at least about 0.0115 Nm to allow sufficient force transfer to allow force to be transferred to the distal end of the assembly 50. 2 In some such examples, the improved dilator 105 has a stiffness or hardness having a bending stiffness value of about 0.0085 Nm 2 ~ approx. 0.0145Nm 2 In one such example, the improved dilator 105 has a bending stiffness of at least about 0.0085 Nm 2 , for example, about 0.0115 Nm 2 In a specific example, the improved dilator 210 has a bending stiffness of about 0.0085 Nm 2 ~ approx. 0.0145Nm 2 Such values ​​provided herein are illustrative of various embodiments of the present invention, however, bending stiffness may vary according to a given implementation of the invention. In some embodiments, the reinforcing member 34 is moldable to allow the shape to be altered to modify the curvature of the improved dilator 105 to optimize the position of the assembly 50 relative to a target tissue site, such as the fossa of the septum of the heart.

[0037] In some embodiments, as shown in FIG. 3, the dilator hub 202 of the improved dilator 105 includes a resilient coupling system 229. FIGS. 10A and 10B show one embodiment of the resilient coupling system 229. The resilient coupling system 229 includes a distal end 231. An outer surface of the distal end 231 engages an inner surface of the sheath hub. In some embodiments, the distal end 231 couples with the sheath hub via a press fit. In an alternative embodiment, the distal end 231 couples with the sheath hub via a snap fit.

[0038] In some cases, the sheath hub specifications may be unknown. This may be due to unpredictable variations in the manufacturing process or working with a sheath manufactured by a third party. In one example, the sheath 310 has a sheath hub 320 that includes a circular opening 322 for a corresponding circular dilator hub. Figures 7A and 7B show a treatment sheath 310 having a sheath hub 320 with a circular opening 322. However, the circular sheath hub 320 and its corresponding circular dilator hub require small tolerances to ensure that when the sheath and dilator are mated, the dilator hub is not too large to fit with the sheath hub or too small to cause insufficient retention of the dilator hub in the sheath hub.

[0039] In such cases, an improved dilator 105 including a hub 202 with a resilient coupling system 229 may be used to accommodate greater tolerances or variability in the sheath hub. In the embodiment of FIGS. 6A-6C, the distal end 231 includes a hexagonal shape and is configured to couple with a circular sheath hub 320. The hub 202 includes a cylindrical body 233 extending proximally of the distal end 231 and includes an angled proximal end 239. The hub 202 further includes a first side 235 and a second side 237 opposite the first side 235. The distal end 231 is made from a resilient material, such as a thermoplastic. In some embodiments, the resilient material is acrylonitrile butadiene styrene (ABS). In alternative embodiments, the resilient material is polycarbonate, high density polyethylene (HDPE), nylon styrene, polypropylene, acetal, or polyethylene terephthalate glycol (PETG). In such embodiments, the outer hexagonal diameter of the hexagonal distal end 231 corresponds to the larger of the tolerances of the sheath hub opening, as shown in FIG.

[0040] In the embodiment of FIG. 8, the hexagonal distal end 231 includes a rounded edge 234 for contacting the inner surface of the sheath hub and a flat portion 336 that forms a gap 360. The gap 360 formed by the flat portion 336 of the hexagon allows space for the material to flex. If the sheath hub is manufactured with a smaller opening, the hexagonal distal end 231 made from an elastic material can flex to accommodate the smaller opening. This is accomplished by the elastic hexagon utilizing the gap 360 to allow the elastic distal end 231 to flex into the gap 360 to allow the hexagonal distal end 231 with a larger outer diameter to fit into a smaller circular sheath hub. In an alternative embodiment, the sheath hub includes a hexagonal opening and the elastic coupling system of the dilator hub includes an elastic circular distal end. In this embodiment, the gap is formed from the flat portion of the sheath hub opening. Similarly, if the sheath hub is manufactured with a smaller opening, the resilient circular distal end may flex towards the gap to accommodate the smaller opening.

[0041] In a particular embodiment, the hexagonal distal end 231 of FIG. 10B has an outer diameter of about 6.5 mm. The resilient coupling system 229 of FIG. 6B fits with a sheath hub having a circular hub with a diameter of about 6.471 mm. In one embodiment, the distal end 231 is press fit into the circular sheath hub. In an alternative embodiment, the distal end 231 may be snap fit into the sheath hub. In some embodiments, the dilator hub 202 comprises a clam shell and the resilient coupling system 229 is disposed at the distal end of the clam shell, as illustrated in FIG. 9.

[0042] In one embodiment, as shown in FIG. 7A, the sheath 310 is a treatment sheath that is part of a treatment assembly that is not configured to support a flexible puncture device. In this example, the improved dilator 105 can be used to support a flexible puncture or punch device 110 while being adapted to be coupled to the treatment sheath 310 via an elastic coupling assembly 229. The workflow of using the improved dilator 105 to support the flexible puncture or punch device 110 and the treatment sheath 310 is described below. FIG. 7B shows a dilator hub 202 with a hexagonal distal end 231 being inserted into a sheath hub 320 with a circular opening 322.

[0043] In some embodiments, the improved dilator 105 includes one or more radiopaque markers. In a particular example, as shown in FIGS. 5A, 5B, and 5C, the radiopaque marker 42 includes a radiopaque coil 142 embedded in the polymer of the improved dilator 105, such as in one or more polymer layers 38 (forming the polymer shaft 39) at the distal tip of the improved dilator 105. In a more particular example, the radiopaque coil 142 is embedded in one or more polymer layers such that the one or more polymer layers extend distally beyond the radiopaque coil 142. In some embodiments, the coil 142 is echogenic and can be visualized using ultrasound imaging. In some embodiments, such as the embodiment shown in FIGS. 4C and 4D, the radiopaque marker 42 can take the form of a ring disposed near the distal tip 143 of the dilator 105.

[0044] In some embodiments of the present invention, a substantially flexible puncture or punching device 110 (such as an RF guidewire) is provided that includes one or more device radiopaque markers (or, in other words, one or more device radiopaque markers) at its distal end. In some such embodiments, as described above, the improved dilator 105 also includes a radiopaque marker at its distal end (as shown in FIGS. 5A-5C). In some such embodiments, the one or more device radiopaque markers are configured to cooperate with the improved dilator radiopaque marker 42 to indicate the relative position of the substantially flexible puncture or punching device 110 (such as an RF guidewire).

[0045] In some embodiments, the reinforcing member 34, such as a metal shaft or hypotube, is also radiopaque. Additionally, in some such embodiments, the polymer forming the improved dilator 105 may include a polymeric radiopaque filler, such as barium sulfate 20%, to provide contrast with the one or more markers 42 at the distal tip. In other words, this allows the user to see the improved dilator 105 under imaging in comparison to the flexible puncture or punch device 110 and whether the flexible puncture or punch device 110 is disposed inside or outside the improved dilator 105 (i.e., whether the distal portion of the flexible puncture or punch device 110 is distal to the improved dilator 105). In an alternative embodiment, the improved dilator 105 includes an echogenic coil at the distal end that can be visualized using ultrasound imaging.

[0046] In some embodiments of the present invention, the improved dilator 105 includes a substantially blunt distal tip or edge 144, as shown in FIG. 4A, to provide a substantially atraumatic distal tip 143 while providing the advantages of a substantially rigid or hard improved dilator 105 (such as by providing a reinforcing member 34). In some such embodiments, as described above, with reference again to FIG. 4A, an improved dilator 105 is provided. The improved dilator 105 includes, in some cases, a substantially blunt distal tip or edge 144 to provide a substantially atraumatic distal tip 144. In some such embodiments, the improved dilator 105 includes a substantially thick distal wall along the distal tip 144, where the distal tip 144 is formed by a substantially rounded distal tip edge. In some such embodiments, the improved dilator 105 provides the benefits of a dilator by providing a substantially atraumatic distal tip to provide trackability and ease of crossing, as well as a tapered profile at the distal tip, while providing the benefits associated with providing a substantially rigid body by including substantially rigid components (such as the reinforcing member 34 therein) in addition to allowing the use of a flexible puncture or punch device 110 for one or more of positioning, tracking device, puncture, and anchoring. As previously discussed, the improved dilator of the present invention provides support for the puncture device and is compatible with the treatment sheath.

[0047] This improves the efficiency of procedures by eliminating several steps from the workflow in procedures that may require specialized therapy devices, such as specialized therapy sheaths, to be used to deliver end therapy devices after gaining access to the left atrium. Some examples of procedures that require specialized therapy devices are cryoablation, left atrial appendage occlusions (LAAO), transcatheter aortic valve replacement (TAVR), transcatheter mitral valve repair, transcatheter mitral valve placement, pulsed field ablation, and RF ablation. These procedures generally require the use of end therapy devices that can only be delivered using sheaths with larger inner diameters than the sheaths used during transseptal puncture. This is because such end therapy devices are larger in size than transseptal puncture devices such as mechanical needles, RF needles, and RF guidewires. Specifically, conventional transseptal puncture sheaths range from 8 to 13 French. Most sheaths are approximately 12.5 French in diameter, although some specialty sheaths, such as those used for cryoablation and LAAO, are sized at 11.5 French or larger. Due to the difference in sheath size between the termination device and the transseptal puncture device, multiple exchanges are typically required to both perform the transseptal procedure (i.e., a procedure to puncture the septum) and deliver the termination device to the left atrium.

[0048] An example of a current conventional workflow for these procedures is shown in FIG. 10. As a general overview, the method involves: (i) obtaining percutaneous venous access, for example to the femoral vein, using a conventional access procedure such as the Seldinger technique 800; (ii) inserting a guidewire into the femoral vein 802; (iii) advancing the guidewire to the superior vena cava (SVC) or right atrium 804. The guidewire is anchored in the SVC or right atrium and serves as a guide rail for advancing other devices; (iv) advancing a dilator and sheath over the guidewire into the SVC or right atrium 806; (v) removing the guidewire 808. The sheath and dilator serve to form a channel through which a puncture device can be advanced; (vi) inserting and advancing a puncture device through the sheath and dilator assembly 810; (vii) the distal tip of the puncture device remains within the lumen of the dilator while (vii) positioning the assembly at a target location on the fossa ovalis (FO) 812. The puncture site may be determined using various visualization methods such as fluoroscopy, electroanatomical mapping, or echogenic markers. The distal tip of the dilator is used to tent the FO, and the puncture device is advanced so that the distal tip of the puncture device contacts the FO, and (viii) punctures the FO in step 814, and the puncture device is advanced so that the distal tip is located within the left atrium. Once puncture is complete, the physician may confirm access into the left atrium via various methods such as fluoroscopy, electroanatomical mapping, pressure differential, contrast injection, or echogenic markers. (xi) Advance the dilator to extend the transseptal puncture across the septum, and cross the septum with a sheath in step 816. (x) Remove the puncture device in step 820, followed by (xi) insert and advance a guidewire into the left atrium in step 822. (xii) Step 824 is performed in which the sheath and dilator are removed, leaving the guidewire behind to act as a guide rail for advancing the specialized device into the left atrium.(xiii) Step 826 is performed to advance a special sheath and dilator over the guidewire. (xiv) Step 828 is performed to widen the puncture with the special dilator to allow advancement of the special sheath. (xv) Step 830 is performed to cross the septum with the special sheath through the enlarged puncture. (xvi) Step 832 is performed to remove the guidewire and special dilator and insert a treatment termination device to complete the procedure.

[0049] Using the device of the present invention, steps of current conventional procedures such as removing the guidewire (step (v), 808), inserting the puncture device (step (vi), 810), withdrawing the puncture device (step (x), 820), and inserting the guidewire (step (xi), 822) can be omitted. Because the RF guidewire has the characteristics of a guidewire and functions as a puncture device, the present invention avoids the need for an additional puncture device and upon completion of the puncture, the RF guidewire can simply be advanced into the left atrium without the need for replacement.

[0050] Another advantage is that the stiffness and exchange length of the RF guidewire provide the necessary support to allow the use of a larger specialized sheath when performing a transseptal puncture. An improved dilator having an inner diameter that accommodates the RF guidewire and an outer diameter that is close to the inner diameter of the larger specialized sheath can be used with the larger sheath. In other words, the dilator is sized to fill the gap between the RF guidewire and the sheath. As a result, the physician can avoid the step of removing the transseptal sheath and the dilator (step (xii), 824), and instead use the larger specialized treatment sheath with the improved dilator to both perform the puncture and deliver the treatment termination device.

[0051] FIG. 11 shows an example of a workflow improved by the use of the present invention. In this method, the following steps are performed: (i) Step 900 of obtaining percutaneous venous access, for example to the femoral vein, using a conventional access procedure such as the Seldinger technique; (ii) Step 902 of inserting a flexible puncture device into the femoral vein; (iii) Step 904 of advancing the flexible puncture device to the SVC or right atrium. The flexible puncture device is anchored in the SVC or right atrium and serves as a guide rail for advancing other devices; (iv) Step 906 of advancing a special treatment sheath and an improved dilator that accommodates the larger outer diameter of the treatment sheath and supports the flexible puncture device over the flexible puncture device into the SVC or right atrium; (v) Step 908 of positioning the assembly at a target location on the FO, during which the distal tip of the flexible puncture device is retracted so that it is located within the lumen of the dilator. The puncture site may be determined using various visualization methods such as fluoroscopy, electroanatomical mapping, or echogenic markers. Step 910 is performed by tenting the FO using the distal tip of the improved dilator, advancing the flexible puncture device so that the distal tip of the RF guidewire contacts the FO, and (vi) puncturing the FO (e.g., by energizing the RF wire if the flexible puncture device is an RF wire) and advancing the flexible puncture device through the septum so that the distal tip is in the left atrium. Once puncture is complete, the physician may confirm access into the left atrium via various methods such as fluoroscopy, electroanatomical mapping, pressure differential, contrast injection, or echogenic markers. Step 912 is performed by advancing the improved dilator across the septum to enlarge the puncture. Step 914 is performed by crossing the septum with a special treatment sheath through the enlarged puncture. (ix) Step 916 is performed in which the flexible puncture device and the improved dilator are removed and a treatment completion device is inserted to complete the procedure.Thus, the number of steps is reduced (i.e., reduced from 16 steps to 9 steps), and the steps of removing the guidewire (step (v), 808), inserting the puncture device (step (vi), 810), removing the puncture device (step (x), 820), reinserting the guidewire (step (xi), 822), and removing the transseptal sheath and dilator (step (xii), 824) are omitted. Since it is no longer necessary to exchange the initial guidewire for a puncture device before puncturing the septum, it is no longer necessary to exchange the puncture device for a guidewire after puncture is completed, and it is no longer necessary to exchange the transseptal sheath and dilator for a special sheath and dilator, the number of exchanges is reduced (i.e., from three exchanges to no exchanges). Finally, the number of devices is reduced (i.e., from six devices to three devices) and with improved workflow there is no separate guidewire and puncture device, and no need for separate transseptal sheaths and dilators as well as specialized sheaths and dilators.

[0052] Reducing the number of required exchanges in this manner provides numerous benefits and advantages in performing these procedures. First, the proposed method does not require any exchanges, so the physician avoids the possibility of misalignment throughout the procedure. In addition, crossing the septum is more efficient, as the physician does not need to dilate the transseptal puncture using a smaller sheath and dilator prior to the passage of a larger sheath and dilator, which also avoids potential difficulties in crossing the atrial septum. Furthermore, since the number of exchanges performed during a procedure is associated with an increased risk of embolism, a reduction in the number of exchanges provides a clinical benefit. In addition, fewer steps or exchanges generally also results in a shorter procedure time.

[0053] In some embodiments, a mechanical puncture guidewire or power wire may be used instead of an RF guidewire. In another embodiment, a movable needle may perform the puncture, but this does not provide any advantage when used as a guidewire. Once the puncture is completed, the movable needle must be removed and replaced with a guidewire. In some embodiments of the present invention, the special treatment sheath may be a fixed curve sheath, while in other embodiments, it may be a sheath that can be steered in one or multiple directions. Alternatively, in some embodiments, multiple telescoping sheaths may be used to improve target site selection.

[0054] The dilator may be an improved dilator 105 that allows the physician to readjust the shape of the dilator during the procedure to optimize the positioning of the distal tip on the FO. The reinforced dilator 105 may include a radiopaque marker 42 disposed at the distal tip. The radiopaque marker 42 may be in the form of a radiopaque band or coil embedded in one of the polymer layers. The radiopaque marker 42 allows the physician to visualize the distal tip of the improved dilator 105 throughout the procedure. The shaft of the improved dilator 105 is dimensioned to accommodate a flexible puncture device and a specialized treatment sheath. Specifically, the inner diameter of the improved dilator 105 corresponds to the outer diameter of the RF guidewire, and the outer diameter of the improved dilator 105 corresponds to the inner diameter of the specialized treatment sheath. In some embodiments, the inner diameter of the shaft may range from 0.035 inches (0.889 mm) to 0.050 inches (1.27 mm), and in some embodiments, the inner diameter may range from 0.038 inches (0.9652 mm) to 0.044 inches (1.1176 mm). The outer diameter of the shaft must be sized to accommodate the special sheath, for example, in some procedures, the outer diameter of the shaft may be 0.151 inches (3.8354 mm) (11.5 Fr) or larger. The wall thickness of the improved dilator 105 varies with the outer diameter. The inner diameter may remain constant, and thus the wall thickness may increase as the outer diameter increases. In some embodiments, the wall thickness may range from 0.056 inches (1.4224 mm) to 0.059 inches (1.4986 mm). The shaft may include a reinforcing member 34 covered with one or more polymer layers. The stiffening member 34 provides rigidity to the assembly, which supports the flexible puncture device during puncture. In addition, the stiffening member 34 supports the special treatment sheath during puncture and while crossing the septum. This is an advantage over current use in the field, as less rigid dilators are currently used that are constructed of softer polymeric materials, which lack the support to puncture and cross the septum.Additionally, due to the softer material, skiving may occur, which forms particulates within the inner lumen. These particulates may be released into the body during the procedure, increasing the risk of embolism. The reinforcing member 34 allows the improved dilator 105 to be shaped either before or during the procedure. The shape-adjusting feature of the improved dilator 105 allows the physician to improve positioning on the septum while increasing the reach of the distal tip (i.e., increasing the distance of the distal tip). Alternatively, the physician can withdraw the improved dilator 105 from the system, shape the improved dilator 105 to a desired curvature, and reinsert the improved dilator 105. Alternatively, the physician may induce the curvature prior to the procedure. Thus, the exemplary workflow described above may include an additional step of shaping the improved dilator 105, either before the start of the procedure or at any time during the puncture. The proximal end of the improved dilator 105 includes a handle 201. The handle 201 includes a hub 202 that is operable to be coupled to the hub of a special sheath.

[0055] In some embodiments, the hub 202 of the improved dilator 105 includes an elastic coupling system 229. The elastic coupling system 229 provides an additional advantage of being able to be detachably coupled to a specialized therapeutic sheath with large or unknown manufacturing tolerances. When the elastic coupling system 229 of the dilator hub 202 couples to the sheath hub of the specialized therapeutic sheath, the improved dilator 105 and the therapeutic sheath can be operated and handled as a single device by the physician. This allows for better control of the improved dilator 105 and the specialized therapeutic sheath during step 906 of advancing into the SVC or right atrium and during step 908 of positioning on the fossa ovalis. Once the puncture is complete, the improved dilator 105 and the therapeutic sheath cross the septum in steps 912, 914. Once the therapeutic sheath crosses the septum, the improved dilator 105 is detached from the therapeutic sheath. Once separated, the treatment sheath and the improved dilator 105 function as two separate devices, and step 916 is performed to remove the improved dilator 105 along with the flexible puncture device, leaving the treatment sheath in the left atrium. Once the improved dilator 105 and the flexible puncture or punch device 110 are removed, a treatment device may be inserted into the treatment sheath and a treatment procedure may begin. Thus, in some embodiments, the system of the present invention provides a workflow that may reduce device exchanges, promote reproducibility, improve dilator-to-sheath coupling, provide proper anchoring, and improve safety.

[0056] 12A and 12B are perspective views of a dilator 105 and a sheath 100 having a mechanism for preventing or inhibiting relative rotation between the dilator 105 and the sheath 100. FIG. 12A and 12B show the dilator 105 inserted into the sheath (FIG. 12A) so that the dilator hub 202 engages with the sheath hub, and the dilator 105 partially inserted into the sheath (FIG. 12B), according to an embodiment of the present invention. As shown, the dilator hub 202 is adapted to mate with the sheath hub 206 when the dilator is fully inserted into the sheath. The hubs 202 and 206 are shaped to prevent or inhibit relative rotation of the dilator 105 with respect to the sheath 100. As shown in FIG. 12A, the tapered surfaces on the hubs 202, 206 guide the dilator hub 202 into the proper engagement orientation when the dilator hub 202 is inserted into the sheath hub 206.

[0057] FIG. 13A is a perspective view of a sheath hub and FIG. 13B is a plan view of a portion of a dilator hub that mates with a sheath hub, according to an embodiment of the present invention. As shown in FIG. 13A, the sheath hub 206 has a generally rectangular opening 210 surrounding a lumen 212 adapted to receive a dilator shaft. As shown in FIG. 13B, the dilator hub 202 has an outer surface 216 shaped to mate and contact with the opening 210 of the sheath hub 206 when the dilator 105 is inserted longitudinally into the sheath. In this mating configuration, the mating surface 217 of the opening 210 and the outer surface 216 contact each other to prevent relative rotation of the components. In various embodiments, the opening 210 has an axially tapered or funnel shape. Additionally, the opening 210 may include one or more curved edges.

[0058] FIG. 14A is a cross-sectional view of a dilator hub mating with a sheath hub, and FIG. 14B is a perspective view of the dilator hub, according to an embodiment of the present invention. As shown in FIG. 14A, the dilator is fully inserted into the sheath, such that the dilator hub 202 is fully engaged with the sheath hub 206. In FIG. 14B, the dilator shaft is omitted to better show the internal features of the dilator hub 202. As shown, the distal end of the dilator hub 202 includes an axial locking feature 220 that includes a series of circumferentially arranged protrusions 224. As shown in FIG. 14A, these protrusions 224 are adapted to engage with corresponding shoulders 236 on the sheath hub 206. The interaction between the protrusions 224 and the shoulders 236 provides resistance to an axial disengagement force, and axially secures the dilator hub 202 within the sheath hub 206. The dilator hub 202 further includes opposing longitudinal faces 230 and 232 extending along the longitudinal axis of the hub, and opposing lateral faces 240 and 242 extending radially outward and generally perpendicular to the longitudinal axis. As shown in FIG. 14A, when the dilator hub 202 is mated with the sheath hub 206, the opposing longitudinal faces 230 and 232 engage corresponding faces of the sheath hub to resist or prevent relative rotation. The corresponding portions may be portions inside the opening 210.

[0059] 15A is a perspective view of a dilator hub and FIG. 15B is a cross-sectional view of the dilator hub mating with a sheath hub, according to an embodiment of the present invention. As shown, the dilator hub 202 includes an angled disengagement surface 250. This surface 250 mates with a corresponding surface 252 on the sheath hub 206. The two surfaces may have slightly different angles or may share a common angle, but are positioned non-parallel to the axis of the dilator, so that upon rotation of the dilator hub 202, the surface 252 generates an axial force against the disengagement surface 250. This axial force causes the dilator hub 202 to disengage from the sheath hub 206. By varying the angle of these surfaces, the amount of torque and degree of rotation required for disengagement can be adjusted.

[0060] Various modifications and additions can be made to the exemplary embodiments described without departing from the scope of the present invention. For example, while the above-described embodiments refer to certain features, the scope of the present invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations that are within the scope of the claims, together with all equivalents thereof.

Claims

1. 1. A system for facilitating access to a patient's heart, comprising: a dilator having a dilator shaft defining a lumen for receiving a puncture device, the dilator shaft being structured to provide support for the puncture device when the puncture device is used to form a puncture in tissue, the dilator shaft having a proximal portion and a distal portion; a dilator hub connected to the proximal portion of the dilator shaft, the dilator hub including a connection system for connecting to a sheath hub.

2. The system of claim 1 , wherein the connection system comprises a resilient connection system.

3. The system of claim 2 , wherein the resilient coupling system includes a hexagonal distal end.

4. The system of claim 2 or 3, wherein the resilient coupling system includes a cylindrical body having an angled proximal end.

5. The system of claim 2 , wherein the resilient coupling system includes a plurality of circumferentially disposed protrusions.

6. The system of claim 1 , wherein the dilator shaft includes a reinforcing member.

7. The system of claim 1 , wherein the distal portion includes a radiopaque marker.

8. a sheath including a sheath body defining a lumen adapted to receive the dilator; 6. The system of claim 1, further comprising a sheath hub coupled to a proximal portion of the sheath body, the sheath hub including a recess for coupling with the connection system to prevent relative rotation between the dilator and the sheath.

9. The system of claim 8 , wherein the recess comprises a generally rectangular shape surrounding the lumen adapted to receive the dilator.

10. 9. The system of claim 8, wherein the coupling system includes a first surface configured to contact a first interior portion of the recess and a second surface configured to contact a second interior portion of the recess.

11. The system of claim 1 , wherein the sheath is a therapeutic sheath.

12. The system of claim 1 , wherein the lancing device is an RF lancing device or a mechanical lancing device.

13. The system of claim 8 , wherein the connection system includes a protrusion adapted to mate with the recess in the sheath hub.

14. 14. The system of claim 8, wherein the dilator hub includes an angled disengagement surface adapted to contact a mating surface on a sheath hub, the mating surface configured to generate an axial disengagement force on the disengagement surface.

15. The system of claim 14 , wherein the angled disengagement surface includes a first surface that is non-parallel to a second surface associated with the mating surface.

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