Support catheters and associated loading components

Abstract

To provide a slit support catheter or the like for assisting in guiding and fixing an interventional device in a blood vessel of a patient during a medical procedure.SOLUTION: Slit support catheters, loading tools, and methods of use are disclosed. A support catheter can include an elongate tubular member and a push member. The tubular member can comprise a longitudinal slit configured to accommodate the exchange of various interventional devices into and out of the lumen defined by the tubular member. A loading tool can comprise a body member, a rod member, or both and can facilitate loading of the support catheter onto one or more interventional devices during a medical procedure. The support catheters can provide intravascular support to various interventional devices and can advantageously be inserted and removed without first removing an interventional device having its distal end at or near a target site within a patient's vasculature.SELECTED DRAWING: Figure 3B

Description

[Technical field]

[0001] [Claim of priority] This U.S. non-provisional patent document claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 149,510, filed February 15, 2021, to Galdonik et al., entitled EXPANDABLE SPLIT SUPPORT CATHETER AND LOADING TOOL DESIGNS, METHODS FOR MANUFACTURE AND METHODS FOR USE, which is incorporated herein by reference in its entirety.

[0002] This patent document relates to medical devices. More specifically, but not exclusively, this patent document relates to a support catheter having attributes configured to support other interventional devices within a patient's vasculature. Also disclosed are accessory devices configured to assemble the support catheter with various interventional devices. [Background technology]

[0003] A guide catheter may be retracted and withdrawn therefrom when an interventional device, such as a guidewire, balloon catheter, stent, or stent catheter, is advanced through a vessel ostium or branch beyond the distal end of the guide catheter. This retraction of the guide catheter may cause the surgeon to lose the ability to further advance the interventional device distally. The interventional device itself may also be unable to access or cross a treatment site, such as a lesion, due to a lack of auxiliary support. A device configured to prevent withdrawal of the guide catheter and provide additional anchoring support for the interventional device should be selected by the surgeon before a medical procedure begins to avoid the need to remove one or more devices from the patient's vasculature during the procedure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 10,173,029 [Patent Document 2] U.S. Patent No. 8,048,032 [Patent Document 3] U.S. Pat. No. 10,751,514 [Patent Document 4] U.S. Pat. No. 10,953,197 Summary of the Invention [Means for solving the problem]

[0005] The inventors recognize that the need to provide increased auxiliary support to an interventional device, such as a guide catheter, during an interventional procedure may be unpredictable. The inventors also recognize that, upon advancement down a vessel during an interventional procedure, a support catheter can increase the success rate of the procedure by "anchoring" the interventional device to the vessel, thereby reducing the likelihood of backing out or dislodging from the target site when advancing another interventional device, such as a balloon or stent delivery system. The inventors also recognize that a support catheter can reduce friction between the interventional device and the surrounding vessel wall, reducing the likelihood of the interventional device getting stuck on calcified and diseased upstream vessel wall tissue. The inventors recognize that support catheters are increasingly used in chronic total occlusion (CTO) and percutaneous coronary intervention (PCI) procedures to increase guide support, as well as provide a target for retrograde wire re-entry. Another useful role for a support catheter recognized by the inventors is to facilitate selective delivery of contrast (e.g., to desired vessel branches), thereby improving angiography with reduced contrast volume.

[0006] The inventors have recognized that currently commercially available support catheters may consist of a proximal handle, a flexible distal tubular structure, and a push rod connecting the handle to the tube. The distal tubular structure may include a radiopaque element such as a round platinum-iridium (Pt-Ir) marker band so that it may be visualized. The distal tube is typically a fully round tube, the wall of which may be composed of an inner lubricious layer (such as a PTFE liner), a support material (such as stainless steel braid), and a polymeric outer layer (such as nylon or Pebax®).

[0007] The inventors further recognize that some existing support catheters have an outer diameter of about 5F, where F is an abbreviation for the French catheter scale (units of measurement catheter diameter (1F=1 / 3 mm)). There are also 4F, 6F, and 7F support catheters on the market. Generally, 4F catheters have an inner diameter greater than or equal to 0.050 inches. Generally, 5F catheters have an inner diameter greater than or equal to 0.059 inches, 6F catheters have an inner diameter greater than or equal to 0.070 inches, and 7F catheters have an inner diameter greater than or equal to 0.078 inches. It is to be appreciated that because the wall thickness of the tubular member of the support catheter can vary, and because of the need for some amount of space between the tubular member of the support catheter and the inner wall of the guide catheter, the inner diameter of the tubular member of the support catheter may vary when the tube does not have a device, such as an interventional cardiac device, inserted therein, and may be smaller than the inner diameter of a correspondingly sized guide catheter. For example, a standard 5F guide catheter may have an inner diameter of 0.059 inches or more, while a 5F support catheter of the present invention may have an inner diameter of about 0.052 inches or less, 0.053 inches, 0.054 inches, 0.055 inches, 0.056 inches, 0.057 inches, 0.058 inches, or 0.059 inches or more in its resting state (with nothing inserted in or through it). When the tubular member of the support catheter is in an expanded state, such as when an interventional cardiac device is inserted therein, the diameter of the tubular member of the support catheter may expand beyond the diameter of the tubular member of the support catheter in its resting state. Certain standard coronary balloon and stent delivery systems can be advanced and withdrawn through the 5F support catheter. Larger catheter systems may be used during rotational atherectomy, bifurcation PCI procedures, and some CTO procedures (e.g., with balloon fixation).The diameter of the support catheter can affect how easily it can be advanced down the coronary arteries, especially given that support catheters are often required for difficult interventional procedures that require navigation through vessels with upstream tortuosity, disease, and calcification.

[0008] The inventors further recognize that to use currently commercially available designs of support catheters, a user must typically first advance the distal tubular structure of the support catheter over the guidewire and into the guide catheter and / or blood vessel. The user must then advance an interventional device (e.g., balloon, stent, etc.) over the guidewire, through the guide catheter, and through the support catheter to reach the target lesion. That is, current market designs do not allow for the support catheter to be inserted after the interventional device, meaning that the user must either preselect when to use the support catheter or completely withdraw the interventional device when the support catheter is needed so that the support catheter can be loaded into the guide catheter first.

[0009] Similarly, the inventors recognize that once a lesion has been treated, the interventional device must then be completely removed in order to remove the support catheter, or both together: the user cannot remove an existing support catheter after its use while leaving the interventional device in the vasculature.

[0010] One reason why current support catheters cannot be directly loaded onto or removed from an interventional device is that these devices typically have a large proximal luer or hub that prevents the tubular support catheter from being loaded onto the proximal end. Thus, the interventional device must be placed after the support catheter is inserted. Related drawbacks to the overall procedure recognized by the inventors include requiring the user to preselect (guess) when a support catheter is needed and to load it first if it is difficult. This approach typically results in a more expensive and longer procedure. If the support catheter is not preselected, the user must withdraw the carefully placed interventional device, load the support catheter, and then reload the interventional device. This also results in a longer and more expensive operation. In addition, after treatment with the interventional device, the support catheter cannot be withdrawn separately, which can complicate the interventional procedure.

[0011] The inventors also recognize that current tubular support catheters often have fixed inner and outer diameters and are not tapered and / or expandable. This means that there will be inherent size differences between the inner diameter of the guide catheter and the outer diameter of the support catheter, and between the inner diameter of the support catheter and the outer diameter of the interventional device. If the size difference between these surfaces is too large, it may result in weak support since the push force applied to the proximal end of the device will not be translated into a 100% forward push. Instead, a typical flexible catheter may meander or even buckle if the radial gap between the devices is too large. The main reason support catheters are used is to constrain the interventional device to ensure that the push force applied proximally will substantially drive the device forward. This also means that current support catheters, since they are not expandable, enter the vessel in their maximum configuration to allow the interventional device to pass, i.e., making it more difficult for the device to track down the cramped vessel.

[0012] The inventors have also recognized that a tension exists between using the smallest diameter support catheter possible so that the interventional device is tightly constrained and the support catheter can be more easily tracked down the cramped vessel versus using the largest possible guide catheter to improve interventional device support. It may be possible to fit the support catheter more tightly over the guidewire or as tightly as possible to the interventional device to improve wire support and pushing. Current support catheters with fixed diameters cannot substantially accommodate guide catheters, interventional devices, and guidewires of different diameters, and do not have the ability to expand in diameter when larger devices are inserted through them.

[0013] The support catheters disclosed herein can be advantageously deployed "on the fly", i.e., without prior selection by the user, after an interventional procedure has begun to provide effective auxiliary support to at least one interventional device already inserted in a blood vessel. A longitudinal slit defined into the distal tubular member of the disclosed support catheter allows the user to insert the support catheter after and over an interventional device by expanding the width of the slit in the distal tubular member of the support catheter and inserting a portion of the interventional device into the distal tubular member. Similarly, the support catheter can be disconnected from the interventional device by pushing the interventional device out of the support catheter through the longitudinal slit in the distal tubular member of the support catheter. Loading the support catheter onto an interventional device after determining that the device requires auxiliary support provides procedural flexibility not available with existing devices, as well as providing for unloading of the support catheter during the procedure. To facilitate the coupling (or mounting) process, accessory devices with a loading tool are also further disclosed herein, along with an optional tying tool that is particularly beneficial for certain interventional procedures.

[0014] Because the support catheters of the present disclosure can be expandable, they may also be used for procedures that typically require catheters with larger diameters. The reduction in device profile can enhance the ease of advancing the catheter down a coronary artery (or other vessel). This may reduce the need for more invasive procedures to distally advance the support catheter, such as balloon anchoring in the distal vessel, which is associated with a higher risk of upstream vessel dissection. The support catheters of the present disclosure may have a reduced diameter only at the distal tip or over the entire length of the elongated tubular member with a longitudinal slit.

[0015] Vascular anchoring provided by the support catheter of the present disclosure may be improved over existing devices primarily because the support catheter can be inserted deeper into the vessel. Stent delivery system protection and support can also be maintained using the support catheter of the present disclosure as the stent on its delivery balloon remains covered around the majority of its circumference.

[0016] Another advantage of the expandable slit support catheter embodiments of the present disclosure is that the catheter can be "clipped" in situ onto the guidewire and balloon / stent delivery catheter shaft, for example, near the Tuohy-Borst hemostatic valve (mounted on the proximal end of the guide catheter), and then advanced down the coronary artery through the guide catheter, all without having to first remove the balloon / stent delivery catheter from the patient.

[0017] The inventors have further recognized that there may be an advantage to quicker and easier removal of the support catheter from the patient. The support catheters of the present disclosure may be removed by withdrawing them from the guidewire and interventional device shaft in a "peel-off" fashion, which may involve withdrawing the tubular member of the support catheter from the guide catheter and peeling the tubular member from the inserted wire / treatment device.

[0018] The support catheter of the present disclosure, in some embodiments, can include a longer distal segment (30-40 cm), a relatively shorter shaft, and an optional additional distal curve to provide directional control within the heart chamber and when crossing the tricuspid valve. These and related embodiments can allow the pacing lead to be delivered to an optimal location within the right atrium and right ventricle, and within the coronary vein accessed through the coronary sinus for left ventricular pacing. This version of the catheter can optionally have a distal curve so that its distal end can be directional controlled. The support catheter can be inserted through a short straight vascular sheath or through a longer sheath with a distal curve designed to engage, for example, the coronary sinus. With the pacing lead fixed in place, the peel-away feature allows for easy removal with minimal risk of lead displacement.

[0019] Various additional improvements to the design, implementation, construction, and / or use of support catheters are described in U.S. Pat. No. 10,173,029, entitled "Deflection Control Catheters, Support Catheters AND Methods of Use," the teachings of which are incorporated herein by reference in their entirety.

[0020] These and other examples and objects of the support catheters, loading components, and related methods of the present invention will be listed in the Detailed Description below. This Summary is intended to provide non-limiting examples of the inventive subject matter, and is not intended to provide an exclusive or comprehensive description. The Detailed Description below is included to provide further information regarding the support catheters, loading components, and related methods of the present invention.

[0021] In the drawings, like numerals may be used to describe like features and components throughout the several views. The drawings illustrate generally, by way of example, and not by way of limitation, various embodiments discussed in this patent document. [Brief description of the drawings]

[0022] [Figure 1A] FIG. 1 is a cutaway cross-sectional side view of a support catheter constructed in accordance with at least one embodiment. [Figure 1B] FIG. 1B is a plan view of the support catheter shown in FIG. 1A. [Figure 1C] FIG. 1B is a cutaway side view of a push member contained within the support catheter shown in FIG. 1A. [Figure 1D] FIG. 1B is an enlarged cross-sectional view of the support catheter taken along line AA of FIG. 1A. [Figure 1E] FIG. 1C is an enlarged side view of a distal portion of the tubular member of the support catheter taken at detail A of FIG. 1B. [Figure 1F] 1B is an enlarged cross-sectional view of the support catheter taken along line AA of FIG. 1A showing the layers and dimensions of the tubular member wall and inner lumen. [Figure 1G] FIG. 1B is a side view of a marker band contained within the support catheter shown in FIG. 1A. [Figure 1H] FIG. 1C is a cross-sectional side view of the marker band shown in FIG. 1G. [Figure 1I] FIG. 1C is a cross-sectional side view of a portion of a distal tubular member including a marker band shown in FIG. 1H. [Figure 2A] FIG. 1 is a fragmentary plan view of a support catheter including a tapered tubular member constructed in accordance with at least one embodiment. [Figure 2B] FIG. 2B is an enlarged cross-sectional view of the support catheter taken at line AA in FIG. 2A. [Figure 2C] FIG. 2B is an enlarged cross-sectional view of the support catheter taken at line BB in FIG. 2A. [Figure 2D] FIG. 2B is an enlarged cross-sectional view of an embodiment of the support catheter taken at line BB of FIG. 2A. [Figure 2E]2B is an enlarged cross-sectional view of another embodiment of a support catheter taken at line BB of FIG. 2A. [Figure 3A] FIG. 1 is a perspective view of a support catheter including a tubular member in a narrow configuration when constructed in accordance with at least one embodiment. [Figure 3B] FIG. 3B is a perspective view of the support catheter of FIG. 3A in an expanded configuration. [Figure 4A] FIG. 1 is a fragmentary plan view of a support catheter that includes a short longitudinal slit when constructed in accordance with at least one embodiment. [Figure 4B] FIG. 4B is an enlarged cross-sectional view of the support catheter taken at line AA of FIG. 4A. [Figure 4C] FIG. 4B is an enlarged cross-sectional view of the support catheter taken at line BB in FIG. 4A. [Figure 5A] FIG. 2 is an enlarged cross-sectional view of a tubular member of a support catheter constructed in accordance with at least one embodiment. [Figure 5B] FIG. 13 is an enlarged cross-sectional view of another tubular member of a support catheter constructed in accordance with at least one embodiment. [Figure 5C] FIG. 5B is an enlarged cross-sectional view of the tubular member of FIG. 5A after insertion of an interventional device. [Figure 5D] FIG. 5C is an enlarged cross-sectional view of the tubular member of FIG. 5B after insertion of an interventional device. [Figure 6] FIG. 1 is a perspective view of a support catheter including a tubular member of variable durometer when constructed in accordance with at least one embodiment. [Figure 7] FIG. 1 is a perspective view of another support catheter constructed in accordance with at least one embodiment. [Figure 8A] FIG. 1 is a perspective view of a support catheter including a cut longitudinal slit as constructed in accordance with at least one embodiment. [Figure 8B] FIG. 8B is an enlarged cross-sectional view of the support catheter taken at line AA of FIG. 8A. [Figure 8C] FIG. 8B is a perspective view of the support catheter of FIG. 8A when detached from the interventional device. [Figure 9]FIG. 1 is a perspective view of a support catheter having a distal tubular structure that defines a proximal side opening when configured in accordance with at least one embodiment. [Figure 10] FIG. 1 is a fragmentary plan view of another support catheter constructed in accordance with at least one embodiment. [Figure 11] FIG. 1 is a perspective view of a support catheter that includes a curved distal end when configured in accordance with at least one embodiment. [Figure 12A] FIG. 1 is an enlarged cross-sectional view of a distal end of a support catheter constructed in accordance with at least one embodiment. [Figure 12B] FIG. 13 is an enlarged cross-sectional view of a distal end of another support catheter constructed in accordance with at least one embodiment. [Figure 12C] FIG. 13 is an enlarged cross-sectional view of a distal end of another support catheter constructed in accordance with at least one embodiment. [Figure 13A] FIG. 1 is a cross-sectional side view of a support catheter including a braided structure when constructed in accordance with at least one embodiment. [Figure 13B] FIG. 13B is an enlarged cross-sectional view of the support catheter taken at detail A of FIG. 13A. [Figure 13C] FIG. 13B is a side view of the support catheter shown in FIG. 13A. [Figure 13D] FIG. 13D is an enlarged cross-sectional view of the support catheter taken at detail B of FIG. 13C. [Figure 14A] 1A-1C illustrate an initial stage of a method of forming a support catheter according to at least one embodiment. [Figure 14B] FIG. 2 illustrates the next step in the method described above. [Figure 14C] FIG. 2 illustrates the next step in the method described above. [Figure 14D] FIG. 2 illustrates the next step in the method described above. [Figure 15A] FIG. 1 is a cross-sectional side view of a support catheter including a metal support structure when constructed in accordance with at least one embodiment. [Figure 15B] FIG. 15B is a perspective view of the support catheter shown in FIG. 15A. [Figure 16A]FIG. 1 is a perspective view of a tubular member of a support catheter that includes a metal support frame when constructed in accordance with at least one embodiment. [Figure 16B] FIG. 16B is a cross-sectional view of the tubular member shown in FIG. 16A. [Figure 16C] FIG. 16B is a plan view of a metal support frame for the tubular member shown in FIG. 16A. [Figure 16D] 16B is a plan view of an alternative embodiment of a metal support frame that may be included within the tubular member shown in FIG. 16A. [Figure 16E] 16B is a plan view of an alternative embodiment of a metal support frame that may be included within the tubular member shown in FIG. 16A. [Figure 16F] 16B is a plan view of an alternative embodiment of a metal support frame that may be included within the tubular member shown in FIG. 16A. [Figure 16G] 16B is a plan view of an alternative embodiment of a metal support frame that may be included within the tubular member shown in FIG. 16A. [Figure 16H] FIG. 13 is a plan view of an alternative embodiment of a metal support frame that may be included within the tubular member of the support catheter. [Figure 16I] FIG. 16C is an enlarged perspective view of a portion of the tubular member including the metal support frame shown in FIG. 16H. [Figure 16J] FIG. 16C is a fragmentary plan view of a portion of the metal support frame shown in FIG. 16H. [Figure 16K] FIG. 13 is a plan view of an alternative embodiment of a metal support frame that may be included within the tubular member of the support catheter. [Figure 17] FIG. 1 is a perspective view of a tubular member of a support catheter including an embedded metal band when constructed in accordance with at least one embodiment. [Figure 18A] FIG. 1 is a perspective view of a support catheter constructed in accordance with at least one embodiment. [Figure 18B] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18C] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18D] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18E] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18F] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18G] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18H] 18B is an enlarged cross-sectional view taken along line AA of a push member that may be included within the support catheter of FIG. 18A. [Figure 18I] FIG. 13 is a perspective view of a support catheter that includes another embodiment of a push member when constructed in accordance with at least one embodiment. [Figure 19A] FIG. 1 is a perspective view of a support catheter including a partially embedded push member when constructed in accordance with at least one embodiment. [Figure 19B] FIG. 13 is a perspective view of another support catheter that includes a partially embedded push member when constructed in accordance with at least one embodiment. [Figure 20A] FIG. 1 is a perspective view of a support catheter including a bifurcated push member when constructed in accordance with at least one embodiment. [Figure 20B] FIG. 20B is an enlarged cross-sectional view of the support catheter shown in FIG. 20A taken along line AA. [Figure 21] FIG. 1 is a perspective view of a support catheter and a compatible interventional device constructed in accordance with at least one embodiment. [Figure 22A] 1A-1C illustrate overview snapshots of a method of using a support catheter and associated interventional device constructed in accordance with at least one embodiment. [Figure 22B]FIG. 22B shows an overview snapshot of the proximal portion of the support catheter and associated interventional device during the method shown in FIG. 22A. [Figure 23] FIG. 13 is a perspective view of a location where a support catheter configured in accordance with at least one embodiment is disconnected from an interventional device. [Figure 24A] FIG. 1 is a perspective view of a technique for loading an interventional device into a support catheter constructed in accordance with at least one embodiment. [Figure 24B] FIG. 13 is a perspective view of another technique for loading an interventional device into a support catheter constructed in accordance with at least one embodiment. [Figure 25A] FIG. 1 is a schematic diagram of a support catheter coupling with an interventional device as constructed in accordance with at least one embodiment. [Figure 25B] FIG. 1 is a schematic diagram of a support catheter coupling with an interventional device as constructed in accordance with at least one embodiment. [Figure 26] FIG. 13 is a close-up view of a distal portion of a support catheter approaching a portion of an interventional device configured in accordance with at least one embodiment. [Figure 27] 1A-1C illustrate a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 28A] FIG. 1 illustrates a perspective view of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 28B] FIG. 28B is a plan view of the loading tool shown in FIG. 28A. [Figure 28C] FIG. 28B is a side view of the loading tool shown in FIG. 28A. [Figure 28D] FIG. 28B is another side view of the loading tool shown in FIG. 28A. [Figure 28E] FIG. 28B is an enlarged side view of the loading tool shown in FIG. 28A taken at detail A of FIG. 28D. [Figure 28F] FIG. 28B is a longitudinal side view of the loading tool shown in FIG. 28A. [Figure 29A]FIG. 1 illustrates a perspective view of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 29B] FIG. 29B is a plan view of the loading tool shown in FIG. 29A. [Figure 29C] FIG. 29B is a side view of the loading tool shown in FIG. 29A. [Figure 29D] FIG. 29B is an enlarged side view of the loading tool shown in FIG. 29A taken at detail A of FIG. 29C. [Figure 30A] FIG. 1 illustrates a perspective view of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 30B] FIG. 30B is a plan view of the loading tool shown in FIG. 30A. [Figure 30C] FIG. 30B is a side view of the loading tool shown in FIG. 30A. [Figure 30D] FIG. 30B is a side view of the loading tool shown in FIG. 30A. [Figure 30E] FIG. 30B is an enlarged side view of the loading tool shown in FIG. 30A taken at detail A of FIG. 30D. [Figure 30F] FIG. 30B is a longitudinal side view of the loading tool shown in FIG. 30A. [Figure 31A] FIG. 1 illustrates a perspective view of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 31B] FIG. 31B is a plan view of the loading tool shown in FIG. 31A. [Figure 31C] FIG. 31B is a longitudinal side view of the loading tool shown in FIG. 31A. [Figure 31D] FIG. 31B is another side view of the loading tool shown in FIG. 31A. [Figure 32A] FIG. 1 is a plan view of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 32B] FIG. 32B is a cross-sectional view of the loading tool shown in FIG. 32A taken along line AA. [Figure 32C]FIG. 32C is an enlarged cross-sectional view taken at Detail B of the loading tool shown in FIG. 32B. [Figure 33A] FIG. 1 is a plan view of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 33B] FIG. 33B is a cross-sectional view of the loading tool shown in FIG. 33A taken along line AA. [Figure 33C] FIG. 33C is an enlarged cross-sectional view taken at detail B of the loading tool shown in FIG. 33B. [Diagram 34] FIG. 13 is a perspective view of another loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Diagram 35] FIG. 13 is a perspective view of another loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Diagram 36] FIG. 13 is a perspective view of a portion of a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 37] FIG. 13 is a perspective view of another loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 38A] 1A-1C illustrate a loading tool configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Figure 38B] FIG. 38B is a cross-sectional view of a portion of the loading tool shown in FIG. 38A. [Figure 38C] FIG. 38B is a cross-sectional view of a portion of an alternative version of the loading tool shown in FIG. 38A. [Figure 38D] FIG. 38B is a cross-sectional view of a portion of an alternative version of the loading tool shown in FIG. 38A. [Figure 38E] FIG. 38B is a cross-sectional view of a portion of an alternative version of the loading tool shown in FIG. 38A. [Figure 38F]FIG. 38B is a cross-sectional view of a portion of an alternative version of the loading tool shown in FIG. 38A. [Figure 38G] FIG. 38B is a cross-sectional view of a portion of an alternative version of the loading tool shown in FIG. 38A. [Figure 39] 1A-1C illustrate a loading tool comprising a trough and a rod configured to facilitate coupling of a support catheter to an interventional device when configured in accordance with at least one embodiment. [Diagram 40] FIG. 13 illustrates a support catheter approaching a loading tool with a rod when configured in accordance with at least one embodiment. [Diagram 41] FIG. 13 illustrates a support catheter approaching a loading tool that includes a rod and a handle when configured in accordance with at least one embodiment. [Diagram 42] FIG. 1 illustrates a loading tool that includes a ring-like feature for user handling when configured in accordance with at least one embodiment. [Diagram 43] FIG. 1 illustrates a bundling tool coupled to a guidewire and an interventional device when configured in accordance with at least one embodiment. [Diagram 44] FIG. 1 illustrates another strapping tool as constructed in accordance with at least one embodiment. [Diagram 45] FIG. 1 illustrates another strapping tool as constructed in accordance with at least one embodiment. [Diagram 46] FIG. 1 illustrates a loading tool comprising an integral bundling feature coupled to a guidewire and an interventional device when constructed in accordance with at least one embodiment. [Figure 47] FIG. 1 illustrates a loading tool comprising a rod and a bundling tube when constructed in accordance with at least one embodiment. [Figure 48] FIG. 1 illustrates a loading tool that includes a single tube when constructed in accordance with at least one embodiment. [Figure 49] 1 illustrates a loading tool including a countersink channel when configured in accordance with at least one embodiment. [Figure 50A]1 is a schematic diagram of a method of inserting a pacemaker lead into a vascular target site according to an embodiment of the disclosure. [Figure 50B] FIG. 50B is a schematic diagram of the next stage of the method shown in FIG. 50A. [Figure 50C] FIG. 50C is a schematic diagram of the next stage of the method shown in FIG. 50B. [Figure 50D] FIG. 50D is a schematic diagram of the next stage of the method shown in FIG. 50C. [Figure 50E] FIG. 50F is a schematic diagram of the next step in the method shown in FIG. 50E. [Figure 50F] FIG. 50F is a schematic diagram of the next step in the method shown in FIG. 50E. [Figure 50G] FIG. 50F is a schematic diagram of the next step in the method shown in FIG. [Figure 51A] FIG. 1 is a schematic diagram of a method for treating a bifurcation lesion according to an embodiment of the present disclosure. [Figure 51B] FIG. 51B is a schematic diagram of the next stage of the method shown in FIG. 51A. [Figure 51C] FIG. 51C is a schematic diagram of the next step in the method shown in FIG. 51B. [Fig. 51D] FIG. 51D is a schematic diagram of the next step in the method shown in FIG. 51C. [Figure 51E] FIG. 51E is a schematic diagram of the next step in the method shown in FIG. 51D. [Fig. 51F] FIG. 1 is a schematic diagram of a guide catheter and a support catheter inserted through an introducer sheath. [Figure 51G] FIG. 51F is a schematic diagram of the next step in the method shown in FIG. 51F. [Fig. 51H] FIG. 51C is a schematic diagram of the next step in the method shown in FIG. 51G. [Fig. 51I] FIG. 51C is a schematic diagram of the next step in the method shown in FIG. 51H. [Figure 52A] 1 is a schematic diagram of a method for inflating a treatment balloon according to an embodiment of the present disclosure. [Figure 52B] FIG. 52B is a schematic diagram of the next stage of the method shown in FIG. 52A. [Figure 52C] FIG. 52C is a schematic diagram of the next step in the method shown in FIG. 52B. [Fig. 52D]FIG. 52D is a schematic diagram of the next step in the method shown in FIG. 52C. [Figure 52E] FIG. 52E is a schematic diagram of the next step in the method shown in FIG. 52D. [Figure 53A] FIG. 13 is a schematic diagram of a support catheter being reloaded onto an interventional device. [Figure 53B] FIG. 1 is a schematic diagram of a support catheter and an interventional device within a guide catheter.

[0023] The drawings are not necessarily to scale: certain features and components may be shown exaggerated in scale or in schematic form and some details may not be shown for purposes of clarity and conciseness. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Various embodiments and aspects of the present disclosure will be described below with reference to the details discussed below, and the accompanying drawings will illustrate these various embodiments. The following description and drawings are generally illustrative of the present disclosure and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the various embodiments of the present disclosure. However, in certain instances, well-known or conventional details are not described to provide a concise discussion of the embodiments of the present disclosure.

[0025] In particular, this patent document discloses a support catheter to be placed within a guide catheter to provide support and guidance in a blood vessel when percutaneously advancing an interventional device, such as a guidewire, balloon catheter, stent, or stent catheter. The support catheter can be inserted into a blood vessel after determining that one or more already inserted interventional devices require or may benefit from additional support. An accessory device for loading the support catheter over a placed interventional device is also disclosed. The support catheter of the present invention has applications in the coronary vasculature, peripheral vasculature, and other vasculature systems.

[0026] The support catheters disclosed herein may comprise a guide extension catheter configured to pass through the main lumen of the guide catheter such that a distal end portion thereof can extend beyond the distal end of the guide catheter, as described, for example, in U.S. Pat. Nos. 8,048,032 (and related cases) and 10,751,514, the entire contents of which are incorporated herein by reference.

[0027] As used herein, an "interventional device" is any device that is inserted into a patient's vasculature to treat a medical condition. An interventional device can provide therapy and / or procedural support. For example, an interventional device can be used to treat a health problem, such as a vascular occlusion or stenotic lesion, and / or can be used to guide another interventional device to a treatment site, where the interventional device can fixate or position the other device. For these purposes, an interventional device is generally an elongated device having a diameter small enough to fit within a patient's blood vessel. An interventional device deployed to treat a vascular lesion can include, for example, a treatment catheter carrying a treatment structure, such as an inflatable balloon, a stent, and / or a distal threaded portion configured to pierce the lesion. An interventional device can include an interventional cardiology device in some embodiments. Additional non-limiting and non-exhaustive examples of interventional devices contemplated herein include stents, stent delivery devices, balloon catheters, balloon delivery devices, and / or pacemaker leads. In this specification, merely for purposes of consistency and simplicity of illustration, "interventional device" and "support catheter" refer to separate devices.

[0028] As used herein, a "user" may be defined as an individual who guides the support catheters and interventional devices of the present disclosure into and out of a patient's vasculature during a medical procedure. Non-limiting examples of users contemplated herein include medical personnel such as treating clinicians, nurses, physicians, interventional cardiologists, and / or physician assistants.

[0029] As used herein, a "blood vessel" may be defined as any vessel within a patient's vascular system, non-limiting examples of which may include the various arteries and veins, including the vascular branches and ostia contained therein. A particular example may include the coronary arteries, but it should be understood that the support catheter may also be used to treat diseased non-coronary vessels, peripheral vasculature, neurovasculature, or other hollow structures throughout the patient's body (such as, for example, bile ducts, ureters, etc.) in which an interventional device is or may be deployed.

[0030] The support catheters described herein (sometimes referred to herein as "expandable slit support catheters," "slit support catheters," or "guide extension catheters") help guide and secure elongated interventional devices within a patient's vasculature during various medical procedures, such as percutaneous procedures directed to difficult to reach vessel branches. A medical device delivery system can include at least one interventional device and a support catheter configured to couple to and rest on the interventional device in an over-the-wire or rapid exchange configuration. When coupled to the interventional device, the support catheter can help resist axial and shear forces that have a tendency to dislodge the interventional device from a seated position that may include the ostium of an arterial branch.

[0031] One embodiment 100 of an expandable support catheter according to the principles of the present disclosure is shown in Figures 1A-1F. Among other features, the support catheter includes an expandable longitudinal slit that extends the entire length of its distal tubular member. The slit can accommodate the insertion and removal of various interventional devices into the tubular member such that the support catheter can be coupled with an interventional device inside the blood vessel after the interventional device has already been inserted into the vessel. When the support catheter is no longer needed, it can simply be withdrawn from the treatment site and disconnected from the interventional device. As described in more detail herein, the configuration of the slit can be varied to accommodate the needs of the user, and the configuration of the tubular member that defines the slit can be varied as well. Although the distal tubular portion is referred to as a "member" throughout this specification, it should be understood that "member" refers to a longitudinal segment or portion, as appropriate, and is not limited to separate structures; rather, one of skill in the art reading this disclosure will understand that these portions of the claimed support catheters can be monolithic, unitary, composed of one, two, or more components or materials, or combinations thereof (oriented longitudinally and / or axially), and that, unless otherwise specified, the term "member" is not intended to limit how the device is constructed.

[0032] The support catheter 100, shown in longitudinal cross section in FIG. 1A, includes a rapid exchange device 102 comprised of a distal sheath or tubular member 104 defining a longitudinal slit 106 and an angled proximal port 108 opposite a distal end opening 110. An internal lumen 111 defined by the tubular member 104 connects the proximal port 108 to the distal end opening 110. The support catheter 100 further includes a push member 112, e.g., a connecting wire or rod, which can be eccentrically coupled to the tubular member 104 at one end and eccentrically coupled to an optional handle member 114 at an opposite proximal end accessible to a user outside the patient's body. The push member 112 can transmit pushing and pulling forces applied by a user to slidably advance or retract the support catheter 100 during a medical procedure without occluding the lumen of the guide catheter, thereby advancing an interventional device together with the push member 112 and further into the tubular member 104 through the proximal port 108. The longitudinal slit 106 can accommodate loading and unloading of the support catheter 100 onto and from various interventional devices during a medical procedure, respectively, which can be accomplished by an expansion of the width of the slit 106 caused by pressing the interventional device through the slit 106 with or without a loading tool, as recited and described in more detail below.

[0033] The handle member 114 can be formed from any material that a user can grip, such as a polycarbonate material. Together with the push member 112, the handle member 114 can allow a user to push the tubular member 104 through a patient's vasculature (or body) to the area of ​​interest. The handle member 114 can be sized or shaped such that it is inhibited from passing through a hemostasis valve that can be attached to the proximal end of a guide catheter into which a portion of the support catheter is inserted.

[0034] The length of the support catheter 100 can vary. In some embodiments, as shown in FIG. 1A, the support catheter has a length of about 150 cm. In additional embodiments, the length of the support catheter 100 can be less than about 50 cm, or about any of 50 cm, 60 cm, 70 cm, 80 cm, 90 cm, 100 cm, 110 cm, 120 cm, 130 cm, 140 cm, 150 cm, 160 cm, 170 cm, 180 cm, 190 cm, 200 cm, or any length greater or between these lengths. The length of the support catheter 100 can be such that the tubular member 104 can reach the distal end or distal portion of an interventional device disposed at a vascular target site. Thus, the support catheter 100 can have a length approximately equal to or slightly less than the length of the interventional device. When adapted for use with a guide catheter or sheath, the support catheter 100 can have a length greater than that of the guide catheter or sheath.

[0035] The length of the tubular member 104 can also vary. In the illustrated example, the tubular member 104 is approximately 17 cm long. Additional examples can feature the tubular member 104 having a length of about 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm, 30 cm, or any length greater or between these lengths. When adapted for use with a guide catheter or sheath, the tubular member 104 can have a length shorter than that of the guide catheter or sheath.

[0036] The proximal port 108 defines a proximal opening of the lumen 111. In the illustrated embodiment, the proximal port 108 includes an angled opening or cutout portion defined by a sloped wall, collar, or concave track that extends from the push member 112 to a full cylindrical portion marking the proximal end 115 of the tubular member 104. In some embodiments, the proximal port 108 may be considered a portion or extension of the push member 112 and / or tubular member 104, particularly if the port 108 is sloped, stepped, or otherwise angled. In some examples, the proximal port 108 may be considered a separate component of the support catheter 100 that is coupled between or integral to the proximal end 115 of the tubular member 104 and the distal end of the push member 112. The metal or polymer structure forming the proximal port 108 can be less stiff or more flexible in the proximal to distal direction to provide a gradual flexibility transition between the stiffer push member 112 and the generally more flexible tubular member 104.

[0037] The shape, angle, and configuration of the port 108 can vary. For example, the proximal port 108 can define a smooth expansion of the circumference (in the distal direction) or a stepped expansion of the circumference defined by one or more flat sections. For example, FIG. 1A illustrates a proximal port 108 having a substantially non-tilted region separated by two sloping regions. In some examples, the proximal port 108 can include a full circumferential portion (which can be the proximal end of the tubular member 104), a semi-cylindrical portion, and an arc-shaped portion from distal to proximal, similar to the tubular portion of the guide extension catheter described in U.S. Pat. No. 8,048,032. In yet other embodiments, the proximal port 108 may not be sloping, but instead define a blunt transverse opening perpendicular to the longitudinal axis of the tubular member 104. The proximal port 108 may have one or more slopes or no slope (i.e., approximately vertical) as desired.

[0038] 1B, the support catheter 100 can include at least one radiopaque marker band 116 within the tubular member 104 to allow visualization and tracking of the catheter within the patient's vasculature. In some embodiments, the support catheter 100 or a portion thereof, such as the distal tubular member 104, can be formed from a radiopaque material. Radiopaque or depth markers can be included on the push member 112.

[0039] 1B further provides a top view of the proximal port 108 showing the full circumference portion 118, the greater than 180° portion 120, and the less than 180° portion 122. The greater than 180° portion 120 can include, for example, structure that forms approximately 300° of the circumference of the tubular member 104. The less than 180° portion 122 can include, for example, structure that forms approximately 90° of the circumference of the tubular member 104.

[0040] 1C illustrates a fragmentary side view of the push member 112. In certain embodiments, the push member 112 can include multiple segments or portions having different hardness and flexibility profiles to provide the support catheter 100 with a desired combination of pushing force and intravascular placement functionality. In this particular embodiment, the push member 112 is tapered distally such that the distal portion 132 has a narrower diameter than the intermediate portion 134, which has a narrower diameter than the proximal portion 136. Alternatively, the push member 112 can have a generally uniform thickness and / or cross-sectional shape along its length. Alternatively, the distal portion of the push member 112 can taper narrower near or adjacent the tubular member 104 and / or have a different cross-sectional shape than the cross-sectional shape of one or more portions of the push member 112 proximal to the region near or adjacent to the tubular member 104.

[0041] The push member 112 can include a flexible rod, wire, or tubular element having a relatively small cross-sectional diameter or other dimension to substantially push the tubular member 104 of the support catheter 100 through the vasculature of the patient while also preventing occlusion of the blood vessel and allowing passage of various interventional devices along with the push member 112. Examples can include a push member 112 with at least one segment comprised of wire only and / or another segment comprised of wire and hypotube, with an optional hypotube cover. An embodiment can also include at least one segment comprised of hypotube to which a wire segment is crimped. For example, the push member 112 can include a proximal portion formed of a hypotube crimped wire adjacent to a wire only segment that extends to and optionally beyond the proximal end 115 of the tubular member 104. Multiple solid core wires of steel or nitinol and one solid core wire wound into a thin wire coil or braid can be used. Alternatively, the push member 112 may have one or more pores that are either fully or partially discrete, intermittent, or continuous along some or all of its length. In general, the push member 112 may comprise an elongated solid wire or rod of fixed or variable dimensions and may comprise a polymeric material or a metallic material such as high tensile stainless steel (e.g., 304V, 304L, or 316LV), mild steel, nickel-titanium alloy, nickel-chromium-molybdenum alloy, nickel-copper alloy, nickel-tungsten alloy, or tungsten alloy. The push member 112 may be coated with a hydrophilic silicone or other friction reducing material. The push member 112 may be made of a hypotube, where the interior of such hypotube is open at both ends and such interior would be too small to allow passage of a balloon or stent catheter along its length.

[0042] 1C, the distal portion 132 of the push member 112 has a cross-sectional diameter of about 0.006 inches, the intermediate portion 134 has a cross-sectional diameter of about 0.008 inches, and the proximal portion 136 has a cross-sectional diameter of about 0.018 inches. The cross-sectional diameters mentioned above are non-limiting and cross-sectional diameters along the push member 112 may range from less than about 0.001 inches to about 0.03 inches or more. Any suitable diameter or diameters that do not interfere with the function or operation of the support catheter 100 may be used.

[0043] The push member 112 can be attached to at least the proximal end of the tubular member and can extend proximally from this attachment to the optional handle member 114, so that the length of the push member 112 can vary depending in part on the length and configuration of the support catheter 100. The push member can be at least partially embedded within or coupled to at least a portion of the tubular member 104. The example shown in FIG. 1C has a length of about 146 cm such that the push member 112 spans nearly the entire length of the support catheter 100. In additional examples, the push member 112 may only extend to or near the proximal end 115 of the tubular member 104. In various embodiments, the length of the push member 112 can be less than about 50 cm, or about 50 cm, 60 cm, 70 cm, 80 cm, about 90 cm, 100 cm, 110 cm, 120 cm, 130 cm, 140 cm, 150 cm, 160 cm, 170 cm, 180 cm, 190 cm, 200 cm, or more, or any length between these lengths. For example, in a specific non-limiting embodiment suitable for deployment in a coronary artery, the push member 112 can have a length of about 95 cm and the tubular member 104 can have a length of about 15 cm. With such an embodiment, the inner diameter of the tubular member 104 can fit over a 4F to 4.5F catheter and the outer diameter can fit within a 6F guide catheter with sufficient clearance between it and the inner diameter of the guide catheter, as discussed below.

[0044] Figure 1D is a cross-sectional side view of support catheter 100 taken along line AA of Figure 1A showing push member 112, angled proximal port 108, and distal tubular member 104. Distal tubular member 104 can have a substantially circular cross-section defining a lumen 111 sized to accommodate the passage of various interventional devices.

[0045] FIG. 1E is an enlarged view of the distal portion of the distal tubular member 104 taken in Detail A of FIG. 1A showing the marker band 116 and the distal portion of the longitudinal slit 106. As shown, the slit 106 can include a straight portion 124 and at least one tapered or curved portion 126 distal thereto (with respect to the longitudinal axis of the tubular member 104). In embodiments, the support catheter 100 can have a continuous straight slit or a slit that is radially curved in one or more locations. In some embodiments, the slit can be curved near its distal end, for example, over the distal 0.25 cm to 3 cm of the tubular member 104. This configuration of the slit 106 can facilitate navigation of the support catheter 100 through tight bends in the vasculature by preventing the slit from opening before it is needed. Although a curved slit 106 is shown, a variety of other non-straight slit configurations can be used for similar purposes. In yet additional embodiments, for example, the tubular member 104 can have a spiral, zigzag, serpentine, or other irregular configuration or a zipper-like longitudinal slit to allow for easy loading over an interventional device while also providing high resistance to accidental cutting of the device.

[0046] The cylindrical wall defining the tubular member 104 may include an outer layer 128 and an inner layer 130 that defines the cross-sectional diameter of the tubular member 104 as shown in the cross-sectional side view of Figure IF. As described in more detail herein, the outer and inner layers 128, 130 may include extrusions of various materials and may be reinforced with a metal framework, braid, or coil.

[0047] In some examples, the support catheter 100 can have a nominal 4F size throughout the entire length of the tubular member 104, thereby allowing such catheter to be inserted through a 5F, 6F, 7F, or 8F guide catheter. The diameter and overall design of the tubular member 104 can be smaller or larger depending on the end use and indication. The inner diameter of the tubular member 104 shown in FIG. 1F is 0.052 inches and the outer diameter is 0.068 inches. In general, the lumen 111 of the tubular member 104 can be sized and shaped to accommodate the passage of one or more interventional devices therethrough. In some embodiments, the inner diameter of the lumen 111 of the tubular member 104 is no more than about 1 French smaller than the inner diameter of the lumen of the guide catheter / sheath through which the support catheter is extended during a medical procedure.

[0048] In general, the tubular member 104 can have an outer cross-sectional dimension that allows it to slide coaxially (i.e., in a tube-in-tube configuration over approximately the same longitudinal axis with room between the tubes) into and through the guide catheter. As shown in FIG. 2B, when the longitudinal edges of the slits are in contact with each other or very close (e.g., within about 1 mm), the following discussion applies to the tubular member 104. For example, in the case of a 6F guide catheter, the tubular member 104 can have an inner diameter about the inner diameter of a 5F guide catheter or any suitable desired diameter. In some embodiments, the inner diameter of the tubular member 104 may be no more than about 1 French smaller than the inner diameter of the guide catheter with which it is used. The difference between the inner diameter of the tubular member 104 and the inner diameter of the guide catheter is related to their respective wall thicknesses and the gap between the outer diameter of the tubular member 104 and the inner diameter of the guide catheter, where the gap must be sufficient to allow the tubular member 104 to be advanced within the guide catheter. For example, the gap between the inner diameter of the guide catheter and the outer diameter of the tubular member 104 can be a distance less than 0.001 inches in cross-sectional diameter, and / or about 0.001 inches, 0.002 inches, 0.003 inches, 0.004 inches, or 0.005 inches, or any distance between these distances. In certain embodiments, the cross-sectional diameter gap can range from about 0.002 to 0.003 inches, or about 0.002 to 0.0035 inches. The diametric gap between the outer diameter of tubular member 104 and the inner diameter of the guide catheter can be approximately continuous along a significant portion or majority of the length of tubular member 104 in some embodiments, or this gap and / or the difference between the inner diameter of tubular member 104 and the inner diameter of the guide catheter can vary along the length of tubular member 104, for example, in one embodiment, a distal portion of tubular member 104 can be tapered. In various embodiments, guide catheters having any diameter can be used.The length of the tubular member 104 can be substantially shorter than the length of the guide catheter, but the tubular member 104 can be designed to have any length according to the desired application, such as anywhere between 6 to 45 cm, 10 to 35 cm, 14 to 25 cm, or 18 to 20 cm, or any other desired length. Although the above discussion has been presented in the context of the slit edges of the tubular member 104 touching or very close to each other (e.g., within about 1 mm), it should be understood that these examples also apply when the slit edges overlap as shown in FIG. 2E, with or without an interventional device inside the tubular member 104, and further when the longitudinal edges of the slits are in an expanded configuration as shown in FIG. 5D due to an interventional device.

[0049] Optional marker bands 116 of the support catheter 100 are shown in Figures 1G and 1H, with the cross-sectional view in Figure 1I showing optional placement of the marker bands 116 relative to the distal tubular member 104. Figure 1G is a side view of the marker bands 116 showing the variable length L. In some embodiments, the length L of the marker bands 116 can be about 0.04 cm. As mentioned above, the tubular member 104 itself can comprise a radiopaque material such that separate marker bands are not included. Other embodiments as shown include one or more individual marker bands having a defined length that may range from less than or about 0.01 cm, or anywhere near 0.02 cm, 0.03 cm, 0.04 cm, 0.05 cm, 0.06 cm, 0.07 cm, 0.08 cm, 0.10 cm or more, or any length between these lengths.

[0050] The marker band 116 can have a substantially cylindrical configuration that extends around the circumference of the tubular member 104. The marker band 116 in FIG. 1H spans approximately 270° around the tubular member 104, leaving approximately 90° (plus or minus approximately 30°) of the tubular member unmarked through which the longitudinal slit 106 extends. In embodiments, the marker band 116 may extend less than or more than 270° around the tubular member 104, for example, near any of 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, 360°, or any value between these values.

[0051] As further seen in FIG. 1H, the cross-sectional thickness of the marker band 116 can be reduced in comparison to the cross-sectional thickness of the wall of the tubular member 104. The inner diameter of the marker band 116 can be about 0.054 inches, plus or minus about 0.0002 inches, and the outer diameter can be about 0.056 inches, again plus or minus about 0.0002 inches. As shown in FIG. 1I, the marker band 116 can be symmetrical or nearly symmetrical (e.g., plus or minus 10 degrees) about the slit 106. The marker band 116 can comprise platinum-iridium, platinum-tungsten, or alloys thereof. Alternatively, one or more marker bands can be formed by impregnating a portion of the tubular member 104 with a radiopaque filter material, such as barium sulfate, bismuth trioxide, bismuth carbonate, tungsten powder, tantalum powder, or the like. The marker band 116 can be of any desired flexibility or rigidity.

[0052] Support catheters, including the support catheter 100 disclosed herein, can be formed from biocompatible materials, non-limiting examples of which include metals such as stainless steel or alloys, e.g., Nitinol, or polymers such as polyether-amide block copolymers (Pebax®), nylon (polyamide), polyolefins, polytetrafluoroethylene, polyester, nylon, polyurethane, polycarbonate, or other suitable biocompatible polymers or composites, and / or combinations thereof. In general, different sections of the support catheter can be formed from different materials than other sections, and multiple sections of the catheter can include multiple materials at different locations and / or specific locations. For example, the proximal extension rod / wire can be formed from a metal such as stainless steel. With respect to the tubular members, one material of particular interest can include a thermoplastic polymer with embedded reinforcements such as wires, braids, or coils that can be metals, suitable polymers, or other materials. Suitable polymer layer materials for the tubular members include, for example, polyamides, i.e., nylon, or Pebax®. The wire can be braided, coiled, or otherwise placed over a polymer tube liner under some tension. A polymer jacket is then placed over the top. After heating above the softening temperature of the polymer and subsequent cooling, the wire becomes embedded in the polymer. The liner and jacket can be the same or different materials. Wires suitable for embedding in polymers include, for example, flat stainless steel wire. The wire adds additional mechanical strength while maintaining a moderate amount of flexibility.

[0053] The materials can be molded, extruded, or the like, for example, according to processing techniques known in the art. The materials can be joined by softening one material and embedding the other material into the softened material, and / or by using mechanical reinforcements, clamps, brackets, or the like. Medical grade materials suitable for adaptation to form the structures described herein are generally commercially available. Curvature can be introduced into the polymeric material by softening the polymer and hardening the polymer over the curved material, or the like.

[0054] As shown in Table 1 below, the components included in the embodiments of the support catheters disclosed herein, such as the outer extrusion of the tubular member, the hypotube, and the marker bands, can each be constructed from one or more optional materials, including, by way of example only, thermoplastic elastomers (e.g., HYTREL SSD 20% BaSO4), stainless steel (e.g., 304SS), and alloys (e.g., Pt10%Ir).

[0055] TIFF2025039774000002.tif51151

[0056] In some embodiments, the expandable support catheters of the present disclosure can be characterized by the proximal end of the tubular member being of a larger diameter than the distal portion. For example, as shown in FIGS. 2A-2C, the support catheter 200 can include a distal tubular member 202 defining a longitudinal slit 204 extending from an angled proximal port 206 to a distal end opening 208. The tubular member 202 tapers distally such that the proximal portion 210 has a larger diameter than the distal portion 212. Additionally or alternatively, it may be desirable for the proximal end 210 to fan out to a larger diameter than the remainder of the tubular member 202. The tubular member 202 can taper from the proximal portion 210 to the distal portion 212 by any desired amount, for example, from just over 0 inches to about 1F to about 2F or more. In an embodiment where the support catheter 200 is specifically configured for use with a 6F guide catheter, the proximal portion 210 of the support catheter 200 can have an outer diameter of 5F and the distal portion 212 can have an outer diameter of 4F. The length of each individual diameter portion can vary along the length of the tubular member 202. For example, the outer diameter could be approximately 5F over the proximal 90mm, taper from approximately 5F to 4F over the next 90mm, and approximately 4F over the distal 90mm of the tubular member 202. A support catheter suitable for use with a 7F guide catheter could similarly taper distally from 6F to 4F throughout its length. In some embodiments, the distal portion 212 of the support catheter can taper less, for example, to 4.5F, or more, for example, to 3.0F or 3.5F. However, in some cases, 4F can be an optimal balance between flatness / delivery capability and reliable stent / balloon delivery system coverage. In some cases, it may be advantageous to taper the tubular member 202 so that the distal tip 214 of the tubular member 202 is only slightly larger than the diameter of the guidewire (e.g., about 0.014 inches, suitable for coronary vascular use), which may have a solid structure or may have an internal structure such as a hollow lumen or core wire.

[0057] The outer diameter of the larger proximal portion 210 of the support catheter 200 fits closely within the inner diameter of the guide catheter or sheath inserted through the support catheter 200, thereby maximizing the diameter of the lumen defined by the tubular member 202 and improving the overall support provided by the support catheter 200 while accommodating the unhindered passage of interventional devices and contrast media therethrough. The lower profile of the distal portion 212 of the tubular member 202 can facilitate delivery of the guide extension down narrow, tortuous vessels. The cross-sectional views of Figures 2B and 2C illustrate the larger cross-sectional diameter of the proximal portion 210 compared to the distal portion 212 along with the longitudinal slit 204.

[0058] The configuration of the tubular member 202 and its longitudinal slit 204 can vary. In some embodiments, the slit 204 can be defined by the parallel juxtaposition of opposing blunt edges or lips 216, 218 of the tubular member 202 such that the space between these lips defines the width of the slit 204. In other examples, the lips 216, 218 can overlap in a pre-use (insertion) configuration prior to coupling with an interventional device, as shown in FIG. 2E. Such an embodiment allows the lips 216, 218 of the slit 204 to either not overlap significantly or to return to the non-overlapping configuration shown in FIG. 2D during or after insertion of an interventional device through the tubular member 202.

[0059] For example, the support catheter 300 shown in Figures 3A and 3B includes a tubular member 302 defining a longitudinal slit 304 configured to be formed and potentially expanded until a gap of variable width is provided between previously overlapping lips 306, 308. Such expansion can occur when an interventional device is being inserted into or removed from the lumen 310 of the tubular member 302. When the slit 304 of the support catheter 300 opens, sufficient circumferential coverage of the interventional device is maintained to retain the interventional device within the lumen 310. This particular configuration can allow for rolling to a very small diameter when navigating tight vessels and / or when used to advance an interventional device that is of an outer diameter significantly smaller than the inner diameter of the tubular member 302. This configuration can be advantageous during medical procedures that include tracking the support catheter 300 directly over a guidewire, as the tightly rolled configuration of the tubular member around the guidewire can prevent the guidewire from being pulled out of the lumen 310 of the tubular member 302 and through the slit 304. In an additional example, the edges or lips of the slit can be interlocked, such as with a barbed configuration, to prevent accidental disengagement of an interventional device inserted within the tubular member.

[0060] In some embodiments, a support catheter of the present disclosure (e.g., any of the support catheters described herein) can incorporate a longitudinal slit that does not travel the entire length of the tubular member. For example, the support catheter 400 shown in Figures 4A-4C includes a tapered tubular member 402 and a longitudinal slit 404 having a proximal end 406 distal to its proximal port, such that there is no slit in the intervening section of the tubular member 402, as shown in the cross-sectional view of Figure 4B. The proximal end 406 of the slit 404 begins near the beginning of the tapered portion of the tubular member 402 (cross-sectional view shown in Figure 4C) and extends all the way to the distal end 410 of the tubular member 402, such that the slit 406 spans approximately two-thirds of the length of the tubular member 402. The length of the slit 404 relative to the length of the tubular member 402 can vary. In some examples, the slit 404 may span at least about 50% of the length of the tubular member, or at least about 60%, 70%, 80%, 90%, 95%, greater than 95%, or any length in between. Such partial slit embodiments may be advantageous in situations where a distal portion of the support catheter is inserted deeper into a vessel of decreasing size, where the slit overlaps between opposing lips to provide a tapered tubular member of smaller size.

[0061] Non-limiting exemplary cross-sectional diameters of the tubular members of the present disclosure near the insertion of an interventional device are depicted in Figures 5A-5D. The 5F tubular member 500a shown in Figure 5A can have an outer diameter 502a of about 0.067 inches and an inner diameter 504a of about 0.056 inches. The 4F tubular member 500b shown in Figure 5B has an outer diameter 502b of about 0.053 inches and an inner diameter 504a of 0.046 inches. Upon insertion of an interventional device 506 through the 5F tubular member 500a, the slit 508a defined by the tubular member 500a can maintain the same or substantially the same width. Insertion of the same interventional device 506 through the tubular member 500b of a 4F catheter may cause the width of the catheter slit 508b to expand. The degree of expansion may vary depending on the number and cross-sectional size of the interventional devices and / or the material composition of the tubular member. In the example shown in FIG. 5D, the reception of the interventional device 506 can expand the slit 508b of the tubular member 500b until the tubular member 500b surrounds about 80% of the circumference of the interventional device 506. In other embodiments, the circumferential coverage of the tubular member remaining after the interventional device is inserted therein can vary over a range of about 50% or more, such as 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or more, or any value between these values. Due in large part to the hoop strength of the tubular member, the circumferential coverage of the interventional device provided by the surrounding tubular member after the insertion of the interventional device therethrough can be sufficient to hold the interventional device within the lumen defined by the tubular member. This residual coverage can be sufficient to efficiently transfer (from the support catheter to the interventional device) the pushing force applied to the proximal end of the support catheter.

[0062] Additionally or alternatively, a support catheter of the present disclosure (e.g., any of the support catheters described herein) may be characterized by a distal end of the distal tubular member shown in FIG. 6 being more flexible than the proximal end, thereby improving maneuverability of the catheter within the patient's vasculature. As shown, the support catheter 600 may include a longitudinal slit 602 across at least a portion of the distal tubular member 604, including a distal portion 606 that is softer than a proximal portion 608. The distal portion 606 may be constructed of a polymer having a durometer hardness of about 25D to about 63D (such as HYTREL, Nylon 12, or Pebax). The distal portion 606 may be constructed of a polymer having a durometer hardness of about 63D to about 72D (such as HYTREL, Nylon 12, or Pebax).

[0063] The number of sections along the tubular member having different durometer hardness may vary over a range of, for example, two, three, four, five, six or more sections. Additional embodiments may include a tubular member having a soft or medium durometer polymer from the proximal end to the distal end, followed by a harder durometer polymer, followed by a soft or medium durometer polymer. In some embodiments, the durometer hardness may vary in a substantially seamless and continuous manner along the length of the distal tubular member 604 such that multiple discrete regions of uniform hardness cannot practically be delineated. In some embodiments, the cross-section of the distal tubular member may comprise multiple materials having different durometer hardness values. In terms of the cross-section of the tubular member, for example, the bottom of the circular cross-section may be made of a softer durometer polymer than the top of the circular cross-section (where the slit is included) to resist unintentional deformation along each side of the slit. Tubular member 604 can have sufficient hoop strength to resist undesired opening along slits 602 as it is advanced through curves and bends in the vasculature.

[0064] In terms of flexural modulus, embodiments of the support catheter may include a first section beginning at the distal end having a flexural modulus of about 13,000 PSI plus or minus 5000 PSI, a second section having a flexural modulus of about 29,000 PSI plus or minus 10,000 PSI, a third section having a flexural modulus of about 49,000 PSI plus or minus 10,000 PSI, and a fourth section having a flexural modulus of about 107,000 PSI plus or minus 20,000 PSI. As will be apparent to one of ordinary skill in the art based on a reading of this disclosure, any number of stiffnesses may be used along the length of some or all portions of the device.

[0065] In yet additional embodiments, the tip of the tubular member can be tapered and flexible such that it can fold back into the lumen of its distal portion upon interaction with an interventional device. The fold back of the distal tip can improve the support of the interventional device provided by the support catheter, which can be advantageous after the interventional device reaches its target site. Thus, the proximal fold back of the distal tip can embody a transition of the primary function of the support catheter from assisting in catheter manipulation to supporting the interventional device. An embodiment can include a flexible tapered distal tip configured to fold back onto the outer surface of the distal portion of the tubular member.

[0066] In some embodiments, the expandable support catheters of the present disclosure (e.g., any of the support catheters described herein) can incorporate a longitudinal slit that varies in cross section along the length of the tubular member. Particular examples can include a longitudinal slit that forms or incorporates one or more enlarged cutout regions, as reflected by the non-limiting example of FIG. 7. The illustrated support catheter 700 includes a distal tubular section 702 opposite an optional handle 704, between which a push member 706 is disposed. A longitudinal slit 708 defined by the tubular member 702 includes a first cutout region 710a proximal to a second distal cutout region 710b, between which narrower regions 712a, 712b, and 712c are disposed. The support catheter 700 can better facilitate clipping of the support catheter over an interventional device. An embodiment may feature only one cutout area, or more than two, for example, four, five, six, or more than six cutout areas.

[0067] In some embodiments, the expandable support catheters of the present disclosure (e.g., any of the support catheters described herein) can incorporate a "second" slit that is fabricated to extend without 100% through the wall of the distal tubular member, as reflected by the non-limiting examples in Figures 8A, 8B, and 8C. The support catheter 800 includes a distal tubular member 802 having a longitudinal slit 804. A cross-sectional view of the distal tubular member 802 along line AA shown in Figure 8B shows a wedge-shaped slit 804 that does not extend through the wall of the tubular member 802 into the inner lumen 806 such that the inner surface of the tubular member 802 remains completely intact. By having a slit that begins to extend but does not extend through the entire wall, a user may be able to use the support catheters of the present invention in the same way as support catheters currently on the market (which are either loaded directly over a guidewire or with the distal end of a guidewire, or reloaded onto an interventional device before introducing the interventional device into the guide catheter). The cut slits allow the support catheter of the present invention to function in the same way as support catheters currently on the market, but unlike current support catheters, the support catheter of the present invention can be removed by tearing the slits and peeling the tubular member away from the interventional device after the support catheter is no longer needed. Additionally or alternatively, it is believed that a support catheter with a perforated slit can be used in a similar manner. FIG. 8C illustrates where an interventional device 808 is removed from the distal tubular member 802 of the support catheter 800 through a slit 804 that tears in a proximal to distal direction during separation of the support catheter 800 and the interventional device 808. In some cases, the support catheter 800 with the cut slit 804 may need to be placed before the interventional device 808. When a cut slit is used, the frangible, intact, and membranous portion of the tube can be on the inner surface, the outer surface, or between them. Alternatively, the slits can be a series of perforations.Where the frangible intact portion of the tube is on the outer wall, it may be formed by molding the tubular portion over a mandrel with appropriately shaped ridges formed longitudinally along its length, such that when the tubular portion is molded over the ridges, the ridges leave cuts along their length in the tubular portion.

[0068] The embodiments of the support catheters disclosed herein can feature a tubular member that defines at least one side port. The support catheter 900 shown in FIG. 9, for example, includes a proximal push member 901 and a tubular member 902. The tubular member 902 defines a distal end opening 904, a proximal port 906, and a side port 908. In addition to preventing backout, the support catheter 900 can deflect an interventional device, such as the illustrated guidewire 910, into an intended vessel branch within a patient's vasculature, as described in more detail in U.S. Pat. No. 10,173,029.

[0069] The side port 908 can be sized and shaped to facilitate the exit of the distal tip 912 of the interventional device therethrough. In some examples, the side port 908 has a longitudinal length greater than at least twice the diameter of the guidewire, for example. At least a portion of the tubular member 902 can have a durometer value approximately equal to or greater than the durometer value of the interventional device 910 to support the device as it is pushed through the side port 908. The tubular member 902 can be flexible enough to open and close over the interventional device 910 while also being rigid enough to remain covering the device 910 as it is pushed into position within the vessel. The longitudinal slit 914 can be formed with intersecting overlapping sections and / or various locking sections.

[0070] In a particular example, the side port 908 has a longitudinal length of about 8 mm. The length of the tubular member distal to the distal end of the side port can be about 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or more, or any length in between these lengths. The support catheter 900 can have one or more curved sections that deflect the side port 908 away from the longitudinal axis of the tubular member 902 that extends from the proximal port 906 to the distal end opening 904.

[0071] In some embodiments, the step of adding slits to the tubular element of the support catheter may require a change to the metal braid or coil co-extrusion in the distal tubular portion according to aspects of the present disclosure. Similarly, there may be a change to radiopaque markers from the ring-marker bands used in some embodiments described herein.

[0072] There are multiple catheter construction options contemplated by the present disclosure. One or more versions of the support catheter discussed above may utilize some or all of these construction methods. In some embodiments, the distal tubular member of the support catheter may be extruded without metal braid or coil reinforcement. This approach allows the polymer used to form the tubular member to be reflowed onto an inner tubular liner (either a polymer such as PTFE or a lubricious one). The durometer of the polymer may vary along the shaft of the support catheter, with the lowest durometer segment generally being near the distal tip (e.g., as reflected by the non-limiting examples in Figures 1A, 1B, and 6). Additionally, the inner and / or outer surfaces of the tubular member may be provided with a slippery coating (hydrophilic or silicone coating) to reduce friction during use. As discussed above, at least a portion of the support catheter can be made radiopaque (visible under x-ray) by loading the polymer with a radio-opacifying agent such as bismuth subcarbonate or barium sulfate, and / or a suitable flexible split marker band is used, in which the Pt-Ir marker includes a split and is embedded into the polymer near the distal tip (within 1 cm, preferably within 0.250 inches to 0.025 inches) (e.g., as reflected by the non-limiting example in FIG. 1E).

[0073] It may be advantageous to tapered or flatten at least a distal portion of the push member, which in some instances may comprise metal or other suitably rigid push shaft material, and attach it to the tubular member, to a reinforcement within the tubular member, and / or to a marker band on the tubular member by welding, adhesive, or bonding, for example, to improve the tensile strength of the assembly shown in the support catheter 1000 of FIG. 10 where the distal portion of the push member is connected to the marker band. In one embodiment, the support catheter 1000 includes a distal tubular member 1002 having a distal marker band 1004 defining a longitudinal slit 1006 opposite a proximal portion of the push member 1008 that includes a wire. The push wire 1008 includes an elongated flat portion 1010 having a ribbon-like cross-sectional shape and which may extend to or near a distal end 1012 of the tubular member 1002. The support catheter 1000 further includes a proximal transition portion 1014, which may be defined by an arc or half-pipe shape, which may be glued, welded, or otherwise secured to the proximal-most flat portion of the push wire 1016. By having a flat ribbon shape and extending the length of the tubular member 1002, the flat portion 1010 of the push wire 1008 can provide a supporting "spine" for the tubular member 1002 and a large area for anchoring the tubular member 1002. The flat portion 1010 can provide tensile strength to the tubular member 1002.

[0074] In one embodiment, the tubular member of the support catheter can be molded to have a curve, for example, by heating and / or cooling to impart a curve to the tubular member into a curved shape (e.g., as reflected by the non-limiting example in FIG. 11), or heated and cooled into a tapered configuration (e.g., as shown in FIGS. 4A-4C). The curved catheter 1100 shown in FIG. 11 includes a distal tubular member 1102 having a curved portion 1104 and a longitudinal slit 1106. A proximal push member 1108 and an optional handle 1110 are also included. The slit can be on the inside of the curve, thereby preventing or inhibiting an interventional device from accidentally exiting the lumen of the tubular member through the slit during use, such as when the tubular member is navigating a tortuous blood vessel. Different embodiments can include multiple curved portions at various points along the distal tubular member.

[0075] The tubular members of the various support catheters can have radiused edges at the distal and / or proximal ends to facilitate the entry and exit of an interventional device (e.g., as reflected by the non-limiting examples in FIGS. 12A-12C). In particular, the distal and / or proximal ends of the tubular members can have radiused outer surfaces, radiused inner surfaces, or radiused inner and outer surfaces. The circumferential wall 1202 of the distal end 1204 of the tubular member in FIG. 12A, for example, has a radiused outer surface 1206. The circumferential wall 1208 of the distal end 1210 of the tubular member shown in FIG. 12B has a radiused outer surface 1212 and an inner surface 1214. The circumferential wall 1216 of the distal end 1218 of the tubular member shown in FIG. 12C has a radiused inner surface 1220. Liners, split radiopaque and / or metallic marker bands, hydrophilic coatings, curves, and tapers are additional features that may be used in combination or not at all for this and all design configurations. Edges may be rounded by heating, removing material, folding the end back on itself, adding material (different or the same), or by other methods.

[0076] In some optional embodiments, the distal tubular member of the support catheter can include one or more polymer layers and a reinforcing member, such as a braid or coil, such that the tubular member includes a layered circumferential wall. In some embodiments, the braid (or coil, longitudinal support, or other reinforcing layer or reinforcing material) can be loaded onto the liner and reflowed with an outer polymer so that the braid (or other reinforcing material) is encapsulated. The assembly is then slit as generally reflected by the longitudinal cross-sectional view of FIG. 13A. The support catheter 1300 includes a distal tubular member 1302 formed according to such an embodiment. The tubular member 1302 defines an inner lumen 1303, and the support catheter 1300 includes a push member 1304 proximal to the distal tubular member 1302. The braided layer 1306 of the tubular member 1302 is encapsulated within an inner liner 1308 and an outer polymer 1310, as shown in more detail in the enlarged view of detail A in FIG. 13B. The inner liner 1308 can be a polymer layer constructed of or coated with silicone, polytetrafluoroethylene (PTFE), or another lubricious material to provide a slippery surface for received interventional devices. The outer polymer 1310 can be a polymer layer constructed of one or more flexible materials such as polyurethane, polyethylene, or polyolefin of sequentially decreasing durometer hardness along the length of the tubular member, which can be coated with a friction-reducing material (e.g., a hydrophilic material or a silicone material) to facilitate insertion and trackability through the vasculature and guide catheter or sheath. The braided layer can comprise, for example, stainless steel or a platinum alloy, and can extend between the polymer layers along at least a portion of the tubular member. As will be recognized by those of skill in the art upon reading this disclosure, any suitable polymer, metal, composite, or other suitable material, or combination thereof, may be used for any desired component, embodiment, portion or portions of the support catheter.

[0077] The side view of Figure 13C shows the longitudinal slit 1312 of the support catheter 1300, and Figure 13D provides an enlarged view of Detail B showing one edge 1314 of the slit 1312 and revealing a cross-section of the braided layer 1306 that is exposed when the tubular member 1302 is cut flush to form the slit 1312.

[0078] 14A-14D depict a braided catheter manufacturing process 1400 performed with at least one mandrel. As shown in FIG. 14A, the process 1400 may involve inserting a first mandrel 1402 through a preliminary unslit distal tubular member 1404 of a catheter 1406 opposite a push member 1408. The distal tubular member 1404 includes a first polymer layer 1410 reflowed onto a cylindrical braid 1412 and an inner liner 1414, all of which define an internal lumen having a diameter smaller than the target diameter of the final distal tubular member. The distal tubular member 1404 is then slit and loaded onto a second, larger mandrel 1416, which expands a slit 1418. A second outer polymer layer 1420 is then reflowed over the braid 1412 to encapsulate the braid and cover the slits 1418, as shown in Figure 14C. The tubular member 1406 is then cut again to form the final slits 1422, as shown in Figure 14D. An optional goal of all embodiments is to ensure that there are no sharp metal braid edges protruding through the polymer surface. It may be advantageous to tape the metal push rod shaft and attach it to the braid and / or marker bands to improve the tensile strength of the assembly.

[0079] Alternatively, a non-metallic material, such as a layer of woven Dacron or carbon fiber (or similar material), can be used in place of the metal braid or coil. According to such an embodiment, a slit can be cut through a tube containing the Dacron or carbon fiber layer.

[0080] In other embodiments, instead of or in addition to a metal braid, a metal "ribbon" or "coil" is added to the distal tubular member. For example, FIG. 15A illustrates a support catheter 1500 including a distal tubular member 1502 having a metal ribbon or coil 1504 surrounding an inner liner 1506. Also included within the tubular member 1502 is a split distal marker band 1508. It is contemplated that one or more proximal metal collars could be attached to the ribbon or coil. Additionally, the perspective view of FIG. 15B illustrates a longitudinal slit 1510 in the tubular member 1502 and the metal ribbon or coil 1504 exposed at the edges of the slit.

[0081] In other embodiments, metal stainless steel tubes can be cut into a pattern and then reflowed into a tubular assembly to provide flexibility. The patterns can be connected end-to-end and stacked to allow for co-extrusion. The metal structure can be cut to extend around approximately 80-90% of the circumference of the distal tube to provide a longitudinal slit in the area lacking the metal structure. This method of production can be slightly more complicated than providing a metal braid, but offers several potential advantages. For example, laser cutting a stent from a 316SS tube using this technique can be relatively inexpensive. Many cutting patterns can be used to form the tubular member, including the option of providing a "spine" to the extruded tubular member. The flexibility of the tube can be varied over the length of the tube by having a row of stent-like frames with different patterns by changing the thickness of the struts (tubes) or by varying the width of the struts. Additional components such as distal marker bands, as well as cuffs and segments for attaching push wires to the proximal end, can be laser cut as part of their respective patterns. These patterns can be designed to interdigitate and align when rows of patterned metal structures are stacked on top of one another. Different alloys such as cobalt chrome or platinum chrome can be used for some or all of the stent to enhance radiopacity. One such design creates radial flexibility but prevents longitudinal compression and / or elongation. Non-limiting examples of optional patterned tubes are presented in the figures of Figures 16A-16J and described below.

[0082] 16A-16C illustrate a support catheter 1600a having a distal tubular member 1602a comprised of a ladder-like metal frame 1603a defined by a number of parallel ribs 1604a with interleaved gaps 1606a therebetween. A longitudinal "spine" 1607a runs the length of the frame 1603a and is integral with and connects the projections 1604a. As shown in the perspective view of FIG. 16A and the plan view of FIG. 16C, the distal end 1608a of the frame 1603a can have a larger area than each of the individual projections 1604a, among other things, to accommodate placement of marker bands. The proximal end 1610a can be attached to or integrally formed with another frame having the same or a different pattern. In the cross-sectional view of FIG. 16B, the slits 1612a in the tubular member 1602a can be seen. The slits 1612a, in some embodiments, can be located approximately opposite the spine 1607a.

[0083] 16D illustrates a snake-like frame 1603b that can be used to form the distal tubular member of the support catheter in a similar manner. The snake-like frame 1603b can be defined, for example, by a series of longitudinal metal segments 1604b connected by a number of transverse metal segments 1606b that terminate at a distal end 1608b having a wide face for integration of a marker band. Similar to frame 1603a, frame 1603b can be stacked with another frame at its proximal end 1610b.

[0084] 16E shows the construction of a stent-like metal frame 1603c that can be cut from a metal tube and used for a tubular member. The frame 1603c includes a series of box-like sections 1604c each defining a central opening 1606c. A series of relatively short longitudinal segments 1608c connect these box-like sections 1604c and provide a longitudinal "spine" for the frame 1603c. The pattern of the frame 1603c can be repeated to increase the longitudinal dimension of the tubular member formed thereby, and / or the frame 1603c can be attached end-to-end with one or more additional frames to form an elongated tubular member composed of a series of individual frames.

[0085] The stent-like frame 1603d shown in Figure 16F also defines a series of box-like structures 1604d with lateral gaps 1606d between them, with successive gaps 1606d alternating between openings on the left and right sides of the structure 1603d with respect to the plan view orientation shown.

[0086] Figure 16G illustrates five additional examples of stent-like frames that may be utilized to form the tubular member of a support catheter according to the present disclosure. The specific configuration of each frame may vary, and as specified by Figure 16G, the frames may comprise a series of repeating features that together define a unitary structure. These frames may or may not include distinct spine features that extend substantially parallel to the longitudinal axis of the resulting tubular member.

[0087] 16H-16J show an embodiment of a stent-like frame with interdigitating features. Frame 1603e shown in FIG. 16H includes a series of stent-like sections 1604e arranged in a row. These sections 1604e are connected through interdigitating features 1606e, which align the stent-like sections 1604e. FIG. 16I illustrates a perspective view of a distal portion of distal tubular member 1602a comprised of frame 1603e formed after rolling the frame into a cylindrical shape. Gaps 1607e left between opposing lateral ends of each frame section 1604e provide space for subsequent formation of longitudinal slits. FIG. 16J is an enlarged view of section 1604e of frame 1603e showing first interdigitating component 1608e opposite complementary interdigitating component 1610e. To stack two or more sections 1604e in series, a first interdigitating projection 1608e can be inserted between two parallel projections 1612e, 1614e that make up a complementary interdigitating component 1610e.

[0088] FIG. 16K shows an additional configuration of patterned frame 1603f that can be used to form the distal tubular member of the support catheter. Frame 1603f includes opposing rounded ends 1404f that resemble coiled wire or springs. These ends, which can overlap, can prevent withdrawal of an interventional device through the longitudinal slit of the support catheter. Frame 1603f differs from frame designs that feature overlapping sides of longitudinal slits, for example, in that the non-overlapping slit sides can expand or maximize the inner diameter of the tubular member formed by the tubular member. The design of FIG. 16K is similar to FIG. 16D in that it can be a continuous (or discontinuous, if desired) material, but can be formed from metal wire formed into a serpentine configuration, or cut or formed from nylon or other polymeric material that is then wrapped, folded, or otherwise formed into the distal tubular member.

[0089] In some embodiments, the support catheter of the present disclosure may incorporate one or more metal split bands of any desired flexibility (or stiffness) throughout the length of the distal tubular member, as shown, for example, in FIG. 17. The support catheter 1700 includes a distal tubular member 1702 comprised of multiple steel bands 1704 embedded within an outer polymer layer 1706 that radially surrounds an inner liner 1708. The bands 1704 may comprise radiopaque materials such as platinum-iridium, steel (e.g., 316SS), or combinations thereof to ensure visibility in some areas and greater clamshell (radial) strength in other areas. Adding metal bands to the tubular member 1702 may improve its radial strength (ensuring that the tubular member resists buckling or twisting) and may force the slits 1710 into a closed configuration. By adding one or more bands 1704 along the length of tubular member 1702, a manufacturer can advantageously control the areas requiring more radial force or force to keep the slits closed.

[0090] As disclosed in more detail herein, a push member can be included within the support catheter, for example, support catheter 1800a shown in FIG. 18A includes distal tubular member 1802a and push rod 1804a. Push rod 1804a can generally be a metallic structure, a polymeric structure, or other suitable rigid structure, or combinations thereof, integral with and / or connected to distal tubular member 1802a, and can optionally include one or more features described in more detail herein.

[0091] The cross-sectional shape of the push rod 1804a can be substantially round (FIG. 18B), elliptical (FIG. 18C), square (FIG. 18D), rectangular (FIG. 18E), semi-lunar concave (FIG. 18F), or flat (FIG. 18G). A possible goal is to provide sufficient force for pushing, but still provide flexibility for the distal tubular member 1802a to pass through various vessel curves and bends. Similarly, it may be desirable to provide as much cross-sectional space as possible between the outer diameter of the interventional device and the inside of the guide catheter. The cross-sectional shape of the push rod 1804a can vary along the length of the rod, for example, the push rod 1804a can be round at the proximal portion (as shown in FIG. 18B) and concave at the distal portion (as shown in FIG. 18F). Other configurations and combinations can be used (e.g., it is contemplated that one or more portions of the push rod 1804a can be in the configuration of FIG. 18H, discussed below).

[0092] FIG. 18H shows another possible cross-sectional shape of at least a portion of the push member, the proximal portion of which is illustrated with a guide catheter 1802b. The illustrated push member 1804b can be defined by an arc-shaped first surface 1806b and a second surface 1808b disposed opposite the first surface. The arc-shaped first surface 1806b can have an outer curvature that matches the inner surface 1807b of the guide catheter. The second surface 1808b can be flat or substantially flat and can be spaced furthest from the first surface 1806b at its center point. Two side surfaces 1810b, 1812b of the arc connect the first surface and the second surface. As described in more detail in U.S. Patent No. 10,751,514, the arcuate or curved shape of the first surface 1806b tracks the inner surface 1807b of the guide catheter 1802b to allow smooth relative movement between the two components. The arcuate shape of the first surface 1806b can enhance or maximize the axial or buckling strength of the push member 1804b. The cross-sectional configuration of the push member 1804b shown generally can improve push force capability and torque control compared to a flat rectangular push member.

[0093] 18I is a perspective view of a support catheter 1800c having a distal tubular member 1802c coupled to a push member 1804c at its distal end 1806c. Surrounding the push member 1804c is a removable support member 1808c that may include a longitudinal slit 1810c extending along its length. The slit 1810c may be formed to be resiliently closed such that the slit 1810c may be peeled open by force to remove the removable support member 1808c from the push member 1804c. The distal end of the removable support member may include a stop or lip member 1812c that may comprise a substantially soft, elastic, or otherwise depressible material configured to affect the tubular member 1802c without damaging it during insertion of the support catheter 1800c into a blood vessel, as described in more detail in U.S. Pat. No. 10,953,197, the entire contents of which are incorporated herein by reference. In some embodiments, the push member can be at least partially attached to the distal tubular member of the support catheter using adhesive bonding, thermal bonding, welding, brazing, etc. In general, the tubular member and the push member can be bonded in a manner that provides a smooth transition between the members. The arrangement or configuration of this bond can vary. For example, the tubular member can include an opening formed in its circumferential wall, and the push member can be disposed within the opening. Insertion of the push member into the opening can result in a mechanical bond between the members, or alternative bonds can be utilized.

[0094] In some embodiments, the push member can vary in size and / or properties (e.g., stiffness) in the region where it interfaces with the tubular member. For example, it may be desirable to increase the flexibility of the push member and extend into the polymeric tubular member wall, as reflected by the diagrams in Figures 19A and 19B. The support catheter 1900a shown in Figure 19A includes a tubular member 1902a and a push member 1904a. An embedded portion 1906a of the push member 1904a is embedded into the circumferential wall of the tubular member 1902a radially separated from the longitudinal slit 1908a. The length of the embedded portion can vary and can extend less than about 5% of the length of the tubular member 1902a, or 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or more, or any amount between these values.

[0095] 19B, the support catheter 1900b can include a push member 1904b having a substantially flat portion 1906b radially separated from a longitudinal slit 1908b. The flat portion 1906b extends approximately the entire length of the tubular member 1902b and terminates in a distally disposed marker band 1910b. The flat portion 1906b of the push member 1904b can be attached directly to the marker band 1910b of the tubular member 1902b or to another metallic component.

[0096] The push member can be attached to any of the aforementioned stiffeners present in the tubular member. Generally, it is desirable to attach the push member to the distal tubular member on the opposite side of the slit, but alternatively, the push member can be attached in a manner that allows it to be on the same side as the slit or at another radial location. FIGS. 20A and 20B, for example, illustrate perspective and cross-sectional views, respectively, of a support catheter 2000 including a tubular member 2002 and a push member 2004. Near the proximal end of the tubular member 2002, the push member 2004 is split longitudinally, thereby forming a fork 2005 comprised of a first protrusion 2006 and a second protrusion 2008, both of which can extend and be attached or embedded within the tubular portion 2002 to form a first embedded protrusion 2010 and a second embedded protrusion 2012. Each embedded protrusion 2010, 2012 can support a side of a longitudinal slit 2014 defined by the tubular member 2002. As shown more clearly in the cross-sectional view of FIG. 20B, the first embedded projection 2010 can be adjacent one side of the slit 2014 and the second embedded projection 2012 can be adjacent the opposite side of the slit 2014, both projections being embedded in the outer polymer layer 2016 surrounding the inner liner 2018. Alternatively or additionally, the push member 2004 can be manufactured of separate longitudinal members that are melted, bonded, or held or fixed together along the length of the push member 2004 until the push member 2004 is close enough to the tubular member 2002 that they are separately attached to the tubular member 2002. The length of each embedded projection 2010, 2012 can vary. In general, the integrity of the slit 2014 can be improved by increasing the length of the projections 2010, 2012 within the tubular member 2002. It should be noted that the slit in this embodiment can be used to further increase the force holding the slit closed by shape memory of the material, relying on magnetic action, or by mechanical engagement features which ensure that both sides of the slit and / or split push member can engage with each other.In some embodiments, the embedding projections 2010, 2012 can be attached with one or more reinforcing structures, such as braids, coils, and / or marker bands. The forks 2005 can be configured to provide a radial closing force against the slits 2014 to prevent the slits 2014 from expanding when undesired. The cross-sectional shape and width of the push member 2004, including the projections 2006, 2008, 2010, 2012, can vary. In some examples, all or at least a portion of the push member 2004 can have a flat and / or tapered cross-sectional configuration.

[0097] The push member may or may not have or be attached to a handle member positioned on the proximal portion or end. Preferably, the handle member would have a larger diameter or other dimension than the push member alone. Optionally, the handle member may be arranged to provide a working length (length from the distal tip of the tubular member to the beginning of the handle) of at least about 110 cm, for example, according to the non-limiting embodiment of FIG. 1A and FIG. 1B. In some embodiments, the push member may have at least one marker positioned along its shaft, which indicates to the user that the distal tip of the support catheter is close to the distal tip of the inserted guide catheter when it approaches the proximal end of the guide catheter. In such an embodiment, preferably, the marker may be positioned at about 100 cm to about 110 cm from the most distal tip of the support catheter, as reflected, for example, by FIG. 21, which shows a support catheter 2100 comprised of a distal tubular member 2102 and a proximal push member 2104. The tubular member 2102 defines a longitudinal slit 2106 and the push member 2104 includes a marker 2108. An interventional device 2110 is shown fitting adjacent to the support catheter 2100. The marker 2108 of the support catheter 2100 is positioned such that when the distal tip of the support catheter 2100 and the distal tip of the interventional device 2110 are aligned, the marker 2108 approximately aligns with a proximal end of the interventional device 2110, which may be defined by the proximal end of the luer / valve 2112.

[0098] Some aspects of the present disclosure relate to various techniques and / or tools that are advantageous for loading and unloading the support catheter of the present disclosure onto and from various interventional devices, respectively. It will be understood that in some instances, one or more combinations of the loading / unloading features described herein may be used with each other. Loading the support catheter according to the present disclosure is described as coupling the support catheter to the interventional device. Coupling may involve inserting the interventional device through a longitudinal slit in the tubular member of the support catheter into a lumen defined by the tubular member. Unloading the support catheter is described as disconnecting the support catheter from the interventional device by removing the interventional device from the lumen of the tubular member of the support catheter through the longitudinal slit. Advantageously, loading and / or unloading the support catheter of the present disclosure can be accomplished without first removing the interventional device from the blood vessel. Loading tools, described below, can facilitate the loading and unloading processes.

[0099] With regard to the unloading method, as described above, the expandable slit support catheter can be unloaded from the guidewire by first withdrawing the interventional device from the guide catheter, then withdrawing and disconnecting the interventional device from the guidewire, and thereafter withdrawing and disconnecting the expandable slit support catheter from the guidewire. Alternatively, it is contemplated that the expandable slit support catheter and interventional device can be removed from each other at the same time, or the support catheter can be removed from the interventional device while the interventional device remains fully or partially disposed within the guide catheter.

[0100] One non-limiting example of the placement of these devices prior to performing these techniques is reflected by the diagrams of Figures 22A and 22B. Figure 22A illustrates the positioning of the guidewire 2202, interventional device 2204, support catheter 2206, and distal end 2200 of guide catheter / sheath 2208 within blood vessel 2210 during the performance of a medical procedure. Guide catheter / sheath 2208 can surround support catheter 2206, which can surround a portion of interventional device 2204 inserted over guidewire 2202. Figure 22B illustrates the positioning of the guidewire 2202, interventional device 2204, and proximal end 2212 of support catheter 2206. The proximal end of support catheter 2206, including a portion of push member 2214 and optional handle 2216, protrudes from the proximal end of access sheath 2218. The proximal end of the guidewire 2202 protrudes from the proximal end of the interventional device 2204 , which may include a proximal luer or proximal hub 2220 .

[0101] In other embodiments, the longitudinal slits of the support catheter of the present disclosure provide an additional option to unload the support catheter from an interventional device, for example, from a guide catheter and / or a therapy delivery catheter shaft and / or guidewire already in place in the coronary artery. As shown in FIG. 23, due to the large hub on the proximal end of some interventional devices, the support catheter 2300 can be unloaded by peeling it through its longitudinal slit 2306 and away from the side of the shaft of the interventional device 2302 and / or the guidewire 2304. This unloading can be accomplished by simply pressing the slit 2306 to open and withdrawing the support catheter 2300 from these components until the shaft of the interventional device 2302 and / or the shaft of the guidewire 2304 is fully removed. More specifically, it may be advantageous to remove the support catheter 2300 from the interventional device 2304 by first pulling the tubular member 2308 and the push member 2310 of the support catheter 2300 away from the shaft of the interventional device 2302 such that the shaft of the interventional device 2302 first exits the proximal-most portion 2312 of the slit 2306, and then continues to be removed in a proximal-to-distal direction, with full removal being achieved when the distal-most portion 2314 of the slit 2306 is removed. This sequence may be performed for one or more versions of the support catheter disclosed herein, including embodiments in which the slit does not initially cut through the entire wall of the tubular member (e.g., FIGS. 8A-8C). In this case, pulling first from the proximal end of the tubular member may tear the slit through the entire wall of the tubular member until the interventional device can be removed, and this tearing will continue in a distal direction until the support catheter is completely separated.

[0102] 24A and 24B show two loading techniques that can be implemented with the device of the present disclosure. As shown in FIG. 24A, an expandable slit support catheter 2400a can be loaded onto the guidewire 2402a by threading the distal tubular member 2404a onto the proximal end of the guidewire 2402a, advancing the tubular member 2404a through a hemostasis valve 2405a coupled to the guide catheter 2406a, and moving the support catheter 2400a distally through the guide catheter / sheath 2406a. This loading can be done when it is known in advance that a support catheter will be needed. Alternatively, as shown in FIG. 24B, the distal end of the interventional device 2408b and / or treatment structure can be preloaded into the proximal end of the support catheter 2400b, and the assembly can be extended in unison over the guidewire 2402b and through the guide catheter / sheath 2406b, which can be coupled to the proximal hemostasis valve 2405b, to the target location within the blood vessel.

[0103] In other embodiments, as reflected by the views of, for example, Figures 25A and 25B, the longitudinal slits provide an additional option to load the expandable slit support catheter over an interventional device already positioned in the coronary artery, such as a balloon / stent delivery catheter shaft and guidewire. A support catheter 2500a and guidewire 2502a are shown with a distal tubular member 2504a and longitudinal slit 2505a that expands over the interventional device 2506a when the support catheter 2500a is pushed distally toward the guide catheter / sheath 2508a. Due to the large hub 2510a on the proximal end of the interventional device 2506a, the slit expandable support catheter 2500a must be loaded over the side of the shaft of the interventional device 2506a and / or guidewire 2502a. This loading can be done by simply pressing the slit 2505a to open and advancing the expandable slit support catheter 2500a over these components until the shaft of the interventional device 2506a and / or the shaft of the guidewire 2502a fit completely into the tubular member 2504a. More specifically, it is advantageous to load the support catheter 2500a over the interventional device 2506a by first loading and advancing the tubular member 2504a and the push member proximally to provide full loading when the proximal-most region of the slit 2505a is loaded. It should be noted that this loading can be performed for both over-the-wire interventional devices where the guidewire is placed inside the interventional device from the tip to the hub, and for rapid exchange interventional devices where the guidewire is placed inside the distal end of the interventional device but outside on the proximal end. 25B shows where a support catheter is loaded onto a rapid exchange device, such as an interventional device. The support catheter 2500b is loaded onto a guidewire 2502b through a tubular member 2504b. The distal portion of the guidewire 2502b is inserted into a rapid exchange interventional device 2506b, which is inserted into a guide catheter / sheath 2508b.

[0104] 25A and 25B further illustrate optional loading tool zones A, B. In some embodiments, a dedicated loading tool can be an advantageous auxiliary device to facilitate the loading process of the support catheter onto one or more interventional devices. When provided, the loading tool of the present disclosure can facilitate clipping the expandable split support catheter onto the shaft of the interventional device (such as balloon, stent), and optionally over the guidewire (for interventional devices of rapid exchange design). The loading tool is designed to make loading quick and easy, and also to ensure that this operation can be performed by one user. In general, all versions of the loading tool design of the present disclosure facilitate one or more of the following:

[0105] Some loading tools of the present disclosure can facilitate alignment by providing axial or coaxial rails that introduce the lumens of the expandable split support catheter into the shaft of the interventional catheter (optionally the shaft of the guidewire) such that all lumens and shafts are supported and introduced in a similar plane. It may be advantageous to introduce the lumens of the expandable split support catheter into the shaft of the interventional catheter so that the radial center of the lumens coincides with the radial center of the shaft. For example, it may be advantageous to introduce the lumens into the shaft at an angle less than 90° or greater than 0°, as shown in FIG. 26, which shows where the support catheter 2600 approaches the interventional device 2602 in the direction of the arrow at an angle α less than 90°. The radial center A of the support catheter 2600 and the radial center B of the interventional device 2602 are preferably in the same plane so that the two devices are aligned to facilitate the loading process.

[0106] The loading tool embodiments described herein may include some variations of axial or coaxial rail guides. For example, the rail guide may take the form of at least one loading structure, such as a channel, rod, or trough, that provides external support and guidance to the support catheter and the interventional device. As shown in FIG. 27, the loading tool 2700 may include a block or body member 2702 that defines a branch channel 2704 that intersects with an angled loading channel 2708 configured to receive and guide the support catheter and is comprised of a straight delivery channel 2706 configured to receive and guide the interventional device. The intersection 2710 of these two channels, where the support catheter is loaded onto the interventional device, defines a boundary between a proximal portion 2712 of the loading channel and a distal portion 2714 of the loading channel. In some embodiments, the delivery channel 2706 intersects at the midpoint of the loading channel 2708 such that the length of the proximal portion 2712 of the loading channel is equal or substantially equal to the length of the distal portion 2714 of the loading channel. The angle α subtended by the proximal side of the intersection 2710 between the delivery channel and the loading channel can be a variety of angles ranging from about 5° to about 85° or any angle between these angles, for example, about 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°.

[0107] 28A and 28B includes a body 2802 defining a branching channel 2804 made up of a straight delivery channel 2806 and an angled loading channel 2808. The angle α defined by the intersection 2810 of the delivery channel 2806 and the loading channel 2808 is approximately 60°, although any suitable angle can be used. The loading channel 2808 includes a proximal portion 2812 and a distal portion 2814 defined by the location of the intersection 2810.

[0108] 28B and 28D, the width w1 of the body member 2802 can be about 1.25 cm, the length l can be about 2.5 cm, and the thickness t can be about 0.25 cm. The cross-sectional width w2 of the delivery channel 2806 can be about 0.04 cm to accommodate an interventional device, and the width w3 of the loading channel 2808 can be about 0.07 cm to accommodate a support catheter. Because the cross-sectional width of the support catheter can be greater than the combined cross-sectional width of the other interventional devices, the width w4 of the distal portion 2814 of the loading channel 2808 can be the same or substantially the same as the proximal portion 2812, which in the illustrated embodiment is 0.07 cm.

[0109] As shown in FIG. 28C, the depth d1 of the delivery channel 2806 can be about 0.07 cm, and the depth d2 of the distal portion 2814 of the loading channel 2808 can be less. In particular, the close-up view of Detail A in FIG. 28E illustrates that the delivery channel 2806 defines a trench-like rail 2816 having a greater depth than the shallower and wider rails 2818 of the loading channel 2808. As shown in more detail in FIG. 28E and FIG. 28F, the depth d2 of the wider rail 2818 of the loading channel 2808 can be less than about 0.015 cm than the trench-like rail 2816 of the delivery channel 2806. Both the delivery channel and the loading channel can have variations in the arc-shaped cross-sectional shape. Additionally, any suitable dimensions can be used with these and other loading tools described herein.

[0110] 29A and 29B provide different views of another loading tool 2900 that includes a body 2902 that defines a branching channel 2904 comprised of a straight delivery channel 2906 configured to receive and guide an interventional device and an angled loading channel 2908 configured to receive and guide a support catheter. The intersection 2910 of these two channels, where the support catheter is loaded onto the interventional device, defines a boundary between a proximal portion 2912 of the loading channel and a distal portion 2914 of the loading channel. The angle α defined by the proximal side of the intersection 2910 can vary and is about 30° in this particular embodiment. In additional embodiments, the angle α may range from about 5° to about 85°, or any angle between these angles, such as any of the following: 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°.

[0111] 29B and 29C, the width w1 of the body member 2902 can be 1.25 cm, the length l can be 2.5 cm, and the thickness t of the body member 2902 can be 0.125 cm. The width w2 of the delivery channel 2906 can be about 0.04 cm to accommodate an interventional device, and the width w3 of the loading channel 2908 can be about 0.07 cm to accommodate a support catheter. Because the cross-sectional width of the support catheter inserted into the loading channel 2908 can be greater than the combined cross-sectional width of the other interventional devices inserted into the delivery channel 2906, the width w4 of the distal portion 2914 of the loading channel 2908 can be the same or substantially the same as the proximal portion 2912, which in the illustrated embodiment is 0.07 cm.

[0112] As shown in more detail in Figures 29C and 29D, the depth of the delivery channel 2906 can be greater than the depth of the loading channel 2908. The close-up of Detail A in Figure 29D illustrates that the delivery channel 2906 defines trench-like rails 2916 that have a greater depth than the shallower and wider rails 2918 of the loading channel 2908. Both the delivery channel and the loading channel can have variations in their arcuate cross-sectional shapes.

[0113] The length of the proximal portion 2912 of the loading channel 2908 may be approximately 1.287 cm, and the length of the delivery channel 2906 and the length of the distal portion 2914 of the loading channel may both be approximately 1.25 cm. The length of each channel may vary and may depend at least in part on the angle α of the intersection 2910.

[0114] 30A and 30B provide different views of another loading tool 3000 comprising a body 3002 defining a branch channel 3004 made up of a straight delivery channel 3006 and an angled loading channel 3008. The intersection 3010 of these two channels defines a boundary between a proximal portion 3012 of the loading channel and a distal portion 3014 of the loading channel. The angle α measured from the proximal side defined by the intersection 3010 of the two channel portions is about 15° in this particular example. In additional embodiments, the angle α may range from about 5° to about 85° or any angle between these angles, for example, any of the following: 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°.

[0115] 30B-30D, the width w1 of the body 3002 can be about 1.25 cm, the length l can be about 2.5 cm, and the thickness t can be about 0.125 cm. The cross-sectional width w2 of the delivery channel can be about 0.045 cm to accommodate an interventional device, and the width w3 of the loading channel can be about 0.08 cm to accommodate a support catheter. The width w4 of the distal portion 3014 of the loading channel 3008 can be the same or substantially the same as the proximal portion 3012.

[0116] Similar to loading tools 2800 and 2900, the delivery channel 3006 defines a narrow trench-like rail 3016, the bottom of which has a greater depth than the shallower and wider rail 3018 of the loading channel 3008. As shown in the cross-sectional view of FIG. 30F, the depth of the rail 3016 of the delivery channel 3006 can extend approximately 0.01 cm below the bottom of the rail 3018 of the loading channel 3008.

[0117] The proximal portion 3012 of the loading channel 3008 may be approximately 1.223 cm long, the distal portion 3014 may be approximately 1.319 cm long, and the delivery channel 3006 may be approximately 1.19 cm long. The length of each channel may vary and may depend at least in part on the angle α of the intersection 3010.

[0118] 30C, the proximal end 3020 of the delivery channel 3006 and the proximal end 3022 of the loading channel 3008 are both exposed proximal 3024 of the body member 3002. The length l2 of the intersection 3010 is significantly greater in this embodiment due to the smaller angle α between the delivery channel 3006 and the proximal portion 3012 of the loading channel 3008. The greater length l2 can facilitate smooth loading and unloading between the support catheter and one or more interventional devices.

[0119] 31A-31D provide views of another loading tool 3100 including a body member 3102 that defines a branching channel 3104, in this case made up of a curved delivery channel 3106 and a curved loading channel 3108. The intersection 3110 of these two channels, where the support catheter is loaded onto the interventional device, defines a boundary between a proximal portion 3112 of the loading channel 3108 and a distal portion 3114 of the loading channel. In some embodiments, the proximal portion 3116 of the loading channel 3108 can be straight or substantially straight, as can the distal portion 3118 of the loading channel.

[0120] 31B-31D, the width w1 of the body member 3102 can be about 2.0 cm, the length l can be about 2.5 cm, and the thickness t can be about 0.125 cm. The cross-sectional width w2 of the distal portion 3114 of the loading channel can be the same or substantially the same as the proximal portion 3112, which in the illustrated embodiment is 0.08 cm.

[0121] 32A-32C provide views of another loading tool 3200 including a body 3202 defining a branching channel 3204 made up of a curved delivery channel 3206 and a curved loading channel 3208. The intersection 3210 of the two channels defines a proximal portion 3212 of the loading channel 3208 and a distal portion 3214 of the loading channel. In some embodiments, the proximal portion 3216 of the loading channel 3208 can be straight or substantially straight, as can the distal portion 3218 of the loading channel.

[0122] As shown in more detail in FIGS. 32A-32C , the proximal portion 3212 of the loading channel 3208 can include an internal lip or rail 3220 that projects into the lumen of the channel 3208, where the internal lip or rail 3220 can maintain the longitudinal slit 3222 of the support catheter 3224 in an open configuration ready to receive an interventional device at the intersection 3210 as the support catheter 3224 slides therealong. The cross-sectional width of the distal portion 3214 can taper distally. In some embodiments, the taper can occur over an extent of about 1 inch. Such an internal lip or rail 3220 can be used on any of the loading tools described herein.

[0123] 33A-33D provide views of another loading tool 3300 including a body member 3302 defining a branch channel 3304 made up of a curved delivery channel 3306 and a curved loading channel 3308. The intersection 3310 of the two channels defines a proximal portion 3312 of the loading channel 3308 and a distal portion 3314 of the loading channel. In some embodiments, the proximal portion 3316 of the loading channel 3308 can be straight or substantially straight, as can the distal portion 3318 of the loading channel. Any desired curvature, angle, straightness, or combinations thereof can be used.

[0124] As shown in more detail in FIGS. 33A-33C, the proximal portion 3312 of the loading channel 3308 can include a rail 3320 with a lip that can be an internal spherical lip or other suitable structure that extends into the lumen of the channel. A longitudinal slit 3322 in the support catheter 3324 slides along the rail 3320, which allows the slit 3322 to be maintained in an expanded position configured to readily accommodate one or more interventional devices when contacted at the intersection 3310. The rail 3320 can taper along the distal portion 3314 of the loading channel 3308 until it no longer protrudes beyond the inner wall of the channel. In some embodiments, the complete taper can occur over about a 1 inch spread of the distal portion 3314 of the loading channel. Because the rail 3320 fits within the support catheter, the maximum outer diameter of the rail 3320 is at least slightly smaller than the inner diameter of the support catheter. In some examples, the outer diameter of the rail 3320 can be about 0.05 inches. The inclusion of the protruding rail 3320 can eliminate the need for the quadrant 3326 of the body member when included in the loading tool described above.

[0125] The cross-sectional diameter of these channels can be about the same as or slightly larger than the outer diameter dimensions of the expandable split support catheter and interventional device (optionally including the guidewire and wire tie features). Similarly, the internal support features can have an outer diameter similar to or larger than the inner diameter of the lumen of the split support catheter (or larger to facilitate opening of the slit). Similarly, as reflected, for example, by FIG. 34, it may be desirable for the support catheter to have a loading structure, e.g., an elongated shaft or rod, be tapered, and / or have an elongated wedge-shaped protrusion, such that it can be easily loaded onto the loading structure and subsequently expand the longitudinal slit as the slit tubular member approaches the shaft of the interventional device (other shapes can be used).

[0126] 34 illustrates a loading tool 3400 comprising a body member 3402 defining a branch channel 3404, again featuring a delivery channel 3406 and a loading channel 3408 that connect at an intersection 3410, the intersection 3410 defining a proximal portion 3412 of the loading channel 3408 and a distal portion 3414 of the loading channel. The proximal portion 3412 of the loading channel defines an inner protrusion or inner wedge 3416 that is thinner at point A than at point B. Upon actuation, the longitudinal slit of the support catheter expands and opens to a diameter equal to or greater than the shaft of an associated interventional device being inserted through the delivery channel 3406 as the support catheter is advanced along the inner wedge 3416 toward point B.

[0127] 35 illustrates a loading tool 3500 comprising a body member 3502 defining a branch channel 3504, again featuring a delivery channel 3506 and a loading channel 3508 that connect at an intersection 3510, the intersection 3510 defining a proximal portion 3512 of the loading channel 3508 and a distal portion 3514 of the loading channel. As shown, the cross-sectional diameter of the distal portion 3514 of the loading channel 3508 tapers distally to close the longitudinal slit of the support catheter around the interventional device and provide a tighter connection between the two components as they are extended through the distal portion 3514 of the loading channel.

[0128] In embodiments, for example, as reflected by Figure 36, the trough or channel of the loading tool may be larger at the intersection between the loading and delivery channels, allowing room for the support catheter to unobstructedly encapsulate the interventional device. The loading tool channel shown includes a branching channel 3604 having a delivery channel 3606 and a loading channel 3608 that meet at an intersection 3610. As shown, the diameter of the delivery channel 3606 at point B is smaller than the diameter of the distal portion 3614 of the loading channel 3608 at point A.

[0129] 37 is a perspective view of another loading tool 3700 featuring an elongated body 3702 or rod defining a longitudinal gap 3704 configured to receive, in this case, a support catheter. The body 3702 includes an arcuate wall 3706 defining a receiving space 3708 configured to receive one or more interventional devices. The unidirectional extension of the support catheter and interventional device along the length of the body 3702 facilitates coupling of the two components as they are extended beyond the end of the body 3702 toward the treatment site. This configuration can facilitate withdrawal of the loading tool from the guide extension wire shaft.

[0130] The axial or coaxial rail guide can take the form of a shaft or rod that provides internal support and guidance, for example, as reflected by the diagram in FIG. 38A. The cross section of the shaft or rod can be circular as shown, but can be non-circular (triangular wedge shaped as reflected by FIGS. 38B-G, square, rectangular, oval, C-shaped, or any desired regular or irregular configuration, etc. or combinations thereof). A combination of multiple cross-sectional shapes can be included within a single loading device. The cross-sectional shapes can vary along the length of the loading tool channel or rod.

[0131] The loading tool can have a combination of loading structures. The embodiments can include at least one elongated rod, channel, and / or trough configured to receive and axially or coaxially slide over a tubular member of a support catheter. Additionally, these loading tool embodiments can include features, such as channels, troughs, rods, wedges, elongated protrusions, rails, or inner shaft / rod combinations, that are specifically configured to open a longitudinal slit in the support catheter, for example, as shown in FIG. 39, which depicts a loading tool 3900 having an internal and external support or guide, such as a combination of rods and troughs. The loading tool 3900 includes a loading rod 3902 attached to a delivery channel or trough 3904. The delivery trough 3904 is configured to receive and guide one or more interventional devices, and the loading rod 3902 is configured to receive and guide a support catheter. The delivery trough 3904 and the loading rod 3902 can be sized to receive and accommodate axial or coaxial sliding of the interventional device and the support catheter, respectively. In some embodiments, it may be advantageous to provide the loading tool 3900 as a multi-component, unassembled device. For example, it may be advantageous to have an inner rod that can be inserted into the distal end of the support catheter until a longitudinal slit in the support catheter scallops open, and to fit this assembly into a body member or block that defines one or more delivery troughs.

[0132] Another optional feature provided by some of the loading tools of the present disclosure is a feature that opens the slits in the support catheter. A feature can be added to the tool that opens the slits and allows them to slide easily over the shaft of the interventional device (e.g., balloons, stents as well as guidewires and optional wire tie features (described below)). An example of this feature is a wedge that is designed to fit into the trough of an axial or coaxial rail so that the slits expand and widen when interacting with the wedge, thereby allowing them to slide over the shaft of the interventional device (e.g., balloons, stents as well as guidewires and optional wire tie features (described below)). Similarly, the internal support feature can have a shaft or rod with an outer diameter sized to be similar to or larger than the inner diameter of the lumen of the split support catheter to facilitate opening of the slits. It may be desirable to have a tapered shaft or rod that can be easily loaded and then begin to expand the slits. 40 includes a loading rod 4000 having a proximal end 4006 and a distal end 4008. The proximal end 4006 has a smaller cross-sectional diameter than the distal end 4008. As the support catheter 4002 is advanced distally along the rod 4000, the longitudinal slit 4010 expands until it intersects with the interventional device 4004. It is contemplated that the tip of the wedge can start small (same as the width of the slit feature) and the largest portion of the wedge can be equal to or larger than the diameter of the interventional device (optionally including a guidewire and optional wire tie features, described below).

[0133] In some embodiments, since the loading tool is designed to allow for use by one single operator, it may be advantageous to have features that free hands and provide stability during loading. For example, the loading tool of the present disclosure can have a flat base to achieve stability. A portion of the block style is designed to be placed face down on a table and is of sufficient length, width, and thickness to ensure stability, for example, as in Figures 34, 35, and 39.

[0134] In some embodiments, the tools of the present disclosure can incorporate handles or other gripping features to allow the user to stabilize the tool with one hand while advancing the support catheter with the other. This can be particularly advantageous for designs that rely on an inner rail to follow a slitted tubular member. In this design, it can be advantageous to have a member protruding from the area that opens the slit so that the tool can be gripped. FIG. 41 provides an example where a loading tool 4100 includes a handle 4102 protruding from the side of a loading rod 4104. The handle 4102 can be substantially flat or wedge-shaped or any other desired shape and can pass through a longitudinal slit 4106 defined by a tubular member 4108 of the support catheter when the tubular member 4108 is inserted over the rod 4104 as long as the slit 4106 and the handle 4102 are in the same plane.

[0135] The loading tool can be configured to be suitable for wearing on a user's finger with a ring-like device attached thereto. For example, FIG. 42 illustrates a loading tool 4200 comprising an elongated rod 4202 and a ring feature 4204 protruding therefrom.

[0136] As mentioned above, there are instances when an expandable split support catheter is loaded over both the balloon shaft and the wire. An interventional procedure may have the simultaneous use of two or more rapid exchange devices. In these applications, a separate temporary split tube may be used to tie the balloon shaft and the wire together, as reflected by FIG. 43, which shows a temporary tie sleeve 4300 including a longitudinal slit 4302, whereby the split support catheter may be loaded over the tie, after which the temporary tube may be removed and optionally discarded. The tie sleeve 4300 may be loaded over the interventional device 4304 and the guidewire 4306, and may further include a handle 4308 to facilitate removal of the sleeve.

[0137] Optionally, the bundling device can have a clamshell design, as shown, for example, in Figures 44 and 45. The bundling device 4400 of Figure 44 includes a first lid 4402, a second lid 4404, and a connection 4406 therebetween. The first and second portions 4402, 4404, when nested or otherwise closed together, form an internal delivery tube 4408 and a cross-loading tube 4410 for receipt of an interventional device and a support catheter, respectively.

[0138] The strapping device 4500 shown in Figure 45 has a "clamshell" configuration featuring a first lid 4502 and a second lid 4504 connected by a longitudinal hinge 4506. The strapping device 4500 further includes a locking mechanism comprised of a lip 4508 configured to engage a corresponding overhanging feature 4510 when the first and second portions 4502, 4504 are folded together through the longitudinal hinge 4506. The particular locking mechanism may vary and may include, for example, a snap-type, clamp-type, or lock-and-key mechanism.

[0139] As shown in more detail in FIG. 45, the bundling device 4500 can include an internal angled surface 4512 configured to expand a longitudinal slit in the support catheter as it approaches the interventional device. Looking at the exterior of the device, the angled surface 4512 can resemble a valley of variable width extending into the device 4500. The configuration of the bundling device 4500 can facilitate removal of the device from the wire shaft and from a manufacturing standpoint may be easy to manufacture, for example, by injection molding. An optional cover or clamshell style lid can be used to help ensure that the device remains in the trough.

[0140] The bundling device can be a separate tool (completely separate from the main loading tool) or can be an integral part of the loading tool, as shown, for example, in FIG. 46. As shown, the loading tool 4600 can include an elongated shaft or rod 4602 that defines a bundling tube 4604 at its distal end. The bundling tube 4604 is configured to receive and hold together various interventional devices, such as a guidewire 4608 and a treatment device 4610. The bundling device can be loaded onto the wires and the shaft of the interventional device and can be removable. Thus, the bundling tube 4604 can include a slit 4612 running parallel to the interventional device that can be clipped onto the interventional device and then removed in a similar manner. The loading and unloading of the slitted bundling tube can be performed in a similar manner to the loading / unloading process used to load / unload the slit support catheters described herein, but on a much smaller scale. The inside diameter of the bundling tube can be about 0.020 inches to 0.070 inches. The outer diameter can be about 0.030 to 0.080 inches. The length of the portion of the slitted tie tube that is loaded over the guidewire and treatment device is about 0.050 cm minimum to about 35 cm maximum, with a preferred length of about 0.5 cm to 10 cm.

[0141] In some embodiments, there can be features that temporarily clip the loading tool onto the shaft of the treatment device (and guidewire shaft or tie). These features can include clips, magnets, or apposition features that result in locking the loading tool to the shaft in a temporary manner, some examples of which are illustrated as components of the loading tool 4700 in FIG. 47. The loading tool 4700 includes a clamshell loading rod 4702 comprised of a first portion 4704 and a second portion 4706 with a connection 4708 therebetween. A tie tube 4710 is coupled or integrally formed with the loading rod 4702. Additionally, the tie tube 4710 can have a clamshell configuration that features a first portion 4712 and a second portion 4714 with a gap or connection 4716 therebetween. A locking mechanism 4718 is configured to lock the first and second portions of the rod together to tie the tubes together. Non-limiting examples of the locking mechanism 4718 may include a magnetic mechanism, a spring force clip, a mechanical lock, or a combination thereof.

[0142] In some embodiments, the loading tool can include a single tube that is a slit and can enclose a hole and an optional handle (e.g., a single tubular loading tool). For example, the loading tool 4800 shown in FIG. 48 includes an angled tube 4802 made up of a proximal loading tube 4804 and a slit tube 4806 that defines a longitudinal slit 4808. The slit tube 4806 can be configured to clip onto an interventional device that is inserted through a through hole 4810 defined thereby. The length of the loading tube 4804 can be longer than the slit tube 4806 to allow for grasping as the loading tube 4804 extends from the slit tube 4806. The loading tube 4804 can also include a longitudinal slit 4812. Additionally or alternatively, an optional handle 4814 can be included for grasping. Although the handle 4812 is shown near the proximal end of the loading tube 4804, in additional embodiments, it can be positioned on the slit tube 4806.

[0143] In some embodiments, the troughs sized to receive the interventional device and support catheter can each include countersinks configured to prevent these devices from easily dislodging from the trough. An example of such a device 4900 is shown in Figure 49. The device 4900 includes a block-shaped body member 4902 that defines a bifurcated trough 4904 made up of a delivery trough 4906 and a loading trough 4908, both of which can be countersinks.

[0144] In addition or in the alternative, one or more of the above-mentioned accessory devices may be provided with or may replace a disposable loading device including a clip member, which allows a user to use the clip member to clip the support catheter onto the interventional device in place and then remove it.

[0145] The support catheters of the present disclosure can be useful in performing a variety of medical procedures, including minimally invasive cardiac interventions, many of which involve the use of guidewires and guide catheters. Guidewires can include an elongated small diameter member designed to navigate a blood vessel to reach a diseased site or vessel segment of interest. Guidewires are available in a variety of configurations, including, for example, a solid core wire of steel or nitinol, and / or a solid core wire encased with a smaller wire coil or braid. A guide catheter or sheath can include an elongated tubular member defining a main lumen along its length. A guide catheter can be formed of polyurethane and can be shaped, for example, along its distal portion to facilitate advancement to a coronary vessel ostium (or other area of ​​interest within a patient). Any suitable size guide catheter, such as a 6F, 7F, or 8F guide catheter, can be inserted in the femoral or radial artery and advanced through the aorta to a position adjacent the ostium of the coronary artery.

[0146] One non-limiting example of an interventional medical procedure that can be performed using the devices disclosed herein in connection with pacemaker lead delivery is described below. Optimal cardiac pacing increasingly requires precise positioning of pacemaker leads into the right heart chambers and / or vascular branches of the coronary venous system. Typically, pacemaker leads are delivered through standard or preformed guide sheaths placed through the cephalic or subclavian veins. Often, these sheaths are designed to be cut or split and stripped when the lead is in place. The electrical connections of a typical pacemaker lead are often significantly larger than the shafts of various existing guide extension catheters. The expandable slit support catheter of the present disclosure, with its distal end located near the desired lead anchoring site, can support optimal positioning and anchoring of the lead. The support catheter of the present disclosure can be particularly advantageous when deploying a pacemaker into the left ventricle through the patient-specific, anatomically variable coronary sinus.

[0147] In some embodiments, a method of delivering a pacemaker lead of the present disclosure includes introducing a guide catheter or sheath 5000 into a blood vessel 5002 and advancing a distal end thereof toward a region of interest 5003, as shown in Figure 50A. By way of example, the blood vessel 5002 can include an aortic arc and the region of interest 5003 can include a cavity of the heart.

[0148] The guide sheath 5000, an elongated tubular member defining a lumen, can have an internal volume of 8F, 7F, or 6F and is commonly used in interventional cardiac procedures. An expandable split support catheter 5004 having a full length longitudinal slit and with or without a distal preset shape can be positioned within the standard or pre-shaped guide sheath 5000 as shown in FIG. 50B and extended through the guide sheath 5000 until the distal end of the support catheter 5004 is at or near the region 5003 of interest. At least one guidewire 5006 having a shaped distal end can be advanced through the sheath 5000 and the support catheter 5004 as shown in FIG. 50C. Alternatively, the guidewire 5006 can be pre-loaded into the support catheter 5004 outside the patient's body and both devices can be introduced together.

[0149] A smaller diameter catheter or "microcatheter" (straight or curved) 5008 can be loaded over the guidewire 5006 and manipulated to the desired location within the region of interest 5003. The expandable split support catheter 5004 can be advanced over the guidewire 5006 and loaded over the smaller diameter catheter 5008 near the desired location, as shown in FIG. 50D. The smaller diameter catheter 5008 can be loaded over the guidewire 5006 and support catheter 5004 outside the patient's body, and these devices can be introduced together.

[0150] Once the target location has been reached, the guidewire 5006 and smaller diameter catheter 5008 can be withdrawn and removed, as shown in Fig. 50E. The pacemaker lead 5012 can then be advanced through the guide sheath 5000 and the expandable split support catheter 5004 to the desired target location 5010 within the region 5003, as shown in Fig. 50F. Further manipulation of the expandable split support catheter 5004 can support final lead positioning and lead fixation. Once the pacemaker lead 5012 is fixed in place, the expandable split support catheter 5004 can be withdrawn and removed, for example, in a peel-off manner as described above, as shown in Fig. 50G. The pacemaker lead 5012 can remain seated at the target location 5010 to complete the interventional procedure.

[0151] In some embodiments, the disclosed method may be relevant for bifurcation lesion PCI procedures. With some bifurcation PCI procedures, it is desirable to simultaneously inflate two treatment structures (e.g., balloons) in a coronary artery (or other vessels in non-coronary procedures) to address bifurcation vessel stenosis that may be caused by a lesion and affect the aorta and adjacent side branches. The treatment structure may include, in some instances, two angioplasty balloons, two stent delivery balloons, or one angioplasty balloon paired with one stent delivery balloon. To treat some lesions with at least two treatment balloons, a support catheter may be required to deliver the first angioplasty balloon or stent delivery balloon to the lesion. Compared to a guide catheter, the support catheter may reduce the luminal cross-sectional area available for delivering and inflating the two treatment balloons. For example, two angioplasty balloons or stent delivery balloons may not be advanceable through current tubular (non-split) 6F-in-5F guide support catheters. Due to the space constraints associated with using a non-split support catheter, once a first angioplasty or stent delivery balloon has been successfully delivered through the support catheter to the lesion, the support catheter must be completely removed from the guide catheter before a second angioplasty or stent delivery balloon can be advanced through the guide catheter. When the first angioplasty or stent delivery balloon is positioned at the lesion, only a short length of the proximal balloon shaft can remain outside of the guide catheter. When the non-split support catheter is pulled back leaving the first angioplasty or stent delivery balloon positioned at the lesion, there may be insufficient proximal balloon shaft length to completely withdraw the support catheter from the guide catheter. The only way to remove the non-split support catheter (without first withdrawing the angioplasty or stent delivery balloon) and allow advancement of the second angioplasty or stent delivery balloon may involve disconnecting the support catheter from the proximal balloon shaft.

[0152] A support catheter in the form of a guide extension catheter having a full length longitudinal slit of the present disclosure can solve the above problems by allowing for easy removal of the support catheter between delivery of a first angioplasty or stent delivery balloon and delivery of a second angioplasty or stent delivery balloon in a tear-away manner. For example, in some embodiments, a method of the present disclosure may involve introducing a guide catheter 5100 through an introducer or access sheath 5102 and advancing the guide catheter 5100 through a blood vessel 5104 toward a blood vessel branch 5106 containing a lesion, as shown in FIG.

[0153] As shown in FIG. 51B, a first guidewire 5108 can be introduced through the access sheath 5102 and extended through the guide catheter 5100 to the branch vessel 5106 and further distally within the branch's aorta 5110.

[0154] 51C, a second guidewire 5112 can be introduced into the guide catheter 5100 and extended distally within a side branch artery 5114 of the branch 5106. Alternatively, the first guidewire 5108 can be inserted prior to or with the guide catheter 5100, with the second guidewire 5112 optionally being inserted partially or subsequently into the guide catheter 5100.

[0155] Next, a first balloon or stent delivery catheter 5116, which may not be configured to be easily advanced to the target site, can be extended over the first guidewire 5108, as reflected by FIG. 51D.

[0156] As shown in FIG. 51E, an expandable split support catheter 5118 can be introduced and inserted distally over both wires 5108, 5112 and the first balloon or stent delivery catheter 5116 within the artery 5104 until the distal end of the support catheter 5118 is near the branch 5106.

[0157] A second balloon or stent delivery catheter can be introduced over one of the guidewires (the first guidewire 5108 in this example) and extended distally to the bifurcation lesion in the aorta 5110, and is shown in FIG. 51F waiting for inflation or stent deployment. If simultaneous inflation of two balloons, two stent delivery catheters, or one balloon and one stent delivery catheter is desired, the second balloon or stent delivery catheter cannot be advanced with the guide extension catheter 5118 due to guide extension inner diameter constraints. Advantageously, the guide extension catheter 5118 can be completely removed by withdrawing it from the guide catheter 5100 and pulling it away from the proximal catheter shaft of the first balloon or stent delivery catheter 5116 and the first guidewire 5108 through the slit, as shown in FIG. 51G. As shown in Figure 51H, a second balloon or stent delivery catheter 5120 can be advanced over the second guidewire 5112 and extended distally to the bifurcation lesion. Simultaneous balloon inflation is performed as shown in Figure 51I. Both balloons 5116, 5120 can then be withdrawn.

[0158] The methods of the present disclosure may further relate to PCI or peripheral intervention to treat one or more lesions. In some embodiments, the methods of the present disclosure may allow for treatment of lesions where the need for a support catheter is not predicted before the procedure begins. Such a method may involve first introducing a guide catheter 5200 into a blood vessel 5204 through an access sheath 5202, as shown in FIG. 52A. As shown in FIG. 51B, a guidewire 5206 may be placed near or extend beyond a target lesion 5208. As reflected by FIG. 52A, a treatment device 5210 may be inserted over the guidewire 5206, thereby attempting therapy.

[0159] The expandable split support catheter 5212 having a full length longitudinal slit 5214, with or without a distal preset shape, can be loaded onto the treatment catheter shaft 5216 extending proximally of the guide catheter 5200 or sheath 5202 as shown in FIG. 52B without having to first remove the treatment device 5210. The step of loading the expandable support catheter 5212 can be performed by pushing open the slit 5214 and loading the entire support catheter tubular member 5218 therethrough onto the treatment device shaft 5216. It may be necessary to load the expandable split support catheter onto both the treatment device and the guidewire if the treatment device is a rapid exchange device. A loading tool can be used during this process.

[0160] The support catheter 5212 is extended to the target lesion 5208 such that the proximal end 5220 of the tubular member 5218 remains within the guide catheter 5200. As shown in FIG. 52C, the distal end 5222 of the tubular member 5218 can be positioned near or beyond the lesion 5208, e.g., proximal to the lesion, and the distal end 5224 of the treatment device 5210 can be pushed across the lesion. When the distal end 5222 of the tubular member 5218 is advanced through and across the lesion 5208, it is partially pulled back with the treatment device 5210 remaining across the lesion. Therapy is then performed by expanding a balloon (with an optional stent) at the distal end of the interventional device, e.g., as in FIG. 52D. The expandable split support catheter 5212 can be withdrawn so that the split tubular member 5218 extends partially or completely outside the proximal end of the guide catheter 5200 or sheath, and the support catheter is stripped or removed from the treatment shaft 5216 and guidewire 5206, as shown in FIG. 52E. The treatment device 5210 can be used again (with the same lesion or another) or removed. At the end of the procedure, the guidewire 5206, guide catheter 5200, and access sheath 5202 are removed (or the guiding sheath is removed).

[0161] In other embodiments, the methods of the present disclosure may allow for treatment of a lesion where the use of a support catheter is anticipated and may include first introducing an access sheath / guide catheter or guiding sheath as shown in Figure 51 A. A guidewire is extended to a location near or beyond the lesion as shown in Figure 51 B.

[0162] The support catheters described herein can provide flexibility to interventional medical procedures in a manner that improves the efficiency and speed of the procedure while also reducing the difficulties commonly associated with procedures that require navigation through tortuous portions of a patient's vasculature. In general, the disclosed support catheters can be deployed during procedures that include, for example, inserting a treatment device through a guide catheter after a guidewire has been extended beyond a vascular lesion. In this case, a user performing a medical procedure may recognize that auxiliary support is required. Rather than removing the treatment device from the patient to make room for the support catheter as has been done in the past, the disclosed support catheters can be inserted over the shaft of the treatment device and advanced through the guide catheter, optionally covering the treatment device completely or partially. As a result, the support catheters of the present invention can rapidly provide sufficient auxiliary support to allow the treatment device to be advanced distally to locations that were inaccessible before the insertion of the support catheter of the present invention.

[0163] In some examples, the support catheter can be reloaded onto an interventional device during a medical procedure. FIG. 53A depicts reloading of a support catheter 5300. As shown, the support catheter 5300 includes a tubular member 5302 that defines a full-length longitudinal slit 5304 and may or may not have a distal preset shape. The support catheter 5300 can be reloaded onto the distal end 5306 of a treatment catheter 5308, after which the two devices can be introduced into the target lesion relative to one another.

[0164] Alternatively, as shown in FIG. 53B, the support catheter 5300 can be introduced over the guidewire 5312 into the guide catheter 5310, and then the treatment device 5308 can be loaded and inserted through the support catheter 5300 and the guide catheter 5310. As reflected by FIG. 52C, the interventional device 5308 can be extended with the support catheter 5300 to the target lesion such that the proximal end 5314 of the tubular member 5302 remains within the distal end 5316 of the guide catheter 5310 near the lesion. The therapy is then performed, for example, as in FIG. 52D. The support catheter 5300 can then be withdrawn such that the split tubular member 5302 extends partially or completely outside the proximal end 5318 of the guide catheter or sheath, for example, as shown in FIG. 52E, and the support catheter is stripped or removed from the treatment shaft and guidewire. Again, the treatment device can be used or removed. At the end of the procedure, the guidewire, guiding catheter, and access sheath are removed (or the guiding sheath is removed).

[0165] Working Example Although the present disclosure has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure. Thus, the above-described "Detailed Description of the Invention" is intended to be illustrative and not restrictive. The above-described embodiments (or one or more features or components thereof) can be used in various combinations with each other unless expressly stated to the contrary. For example, those skilled in the art can use other embodiments after reading the above-described "Detailed Description of the Invention". Similarly, various features or components have been grouped together to streamline the disclosure of the invention. Features of the present disclosure that are not claimed should not be construed as intended to be essential to any claim. Rather than being essential, the subject matter of the invention may reside in less than all features of a particular embodiment disclosed. Thus, the following examples of claims, each of which stands as a separate and distinct embodiment in its own right, are incorporated into this "Detailed Description of the Invention". EXAMPLES

[0166] In Example 1, a device suitable for use with a support catheter and at least one interventional device can include a body with an elongated delivery channel sized to receive the interventional device and accommodate axial sliding of the interventional device. The device can also include an elongated loading structure sized to receive a tubular member of the support catheter and accommodate axial sliding of the tubular member of the support catheter. A distal end of the elongated loading structure intersects the elongated delivery channel along a length of the elongated delivery channel. EXAMPLES

[0167] In Example 2, the device of Example 1 can be optionally configured such that the elongated loading structure comprises a channel having a wedge-shaped protrusion extending along its length, the cross-sectional dimension of the wedge-shaped protrusion varying along the length of the wedge-shaped protrusion. EXAMPLES

[0168] In Example 3, the device of Example 1 or Example 2 can optionally be configured such that a distal portion of the elongate delivery channel tapers to a smaller width than a proximal portion of the elongate delivery channel. EXAMPLES

[0169] In Example 4, a device suitable for use with a support catheter and at least one interventional device can include an elongate loading rod sized to be inserted into a tubular member of the support catheter. The elongate loading rod also has a distal end configured to couple with a shaft of the interventional device. The distal end of the elongate loading rod has a larger dimension than the proximal end of the elongate loading rod. EXAMPLES

[0170] In Example 5, the device of Example 4 can be optionally configured to further include a handle protruding from a side of the elongate loading rod and configured for user interaction. EXAMPLES

[0171] In Example 6, the device of Example 4 or Example 5 can optionally be configured such that the distal end of the elongate loading rod defines a cylindrical portion configured to bundle one or more interventional devices together. EXAMPLES

[0172] In Example 7, the device of any one or any combination of Examples 4-6 can be optionally configured to further include two longitudinal components defining an interface therebetween. The two longitudinal components can be configured to separate along their lengths, thereby creating a longitudinal gap therebetween. The device can further include a locking mechanism configured to reduce a width of the longitudinal gap by bringing the longitudinal components closer together along their lengths. EXAMPLES

[0173] In Example 8, a method of delivering two elongate medical devices to a lesion at a vessel bifurcation in a patient includes positioning a first guidewire and a second guidewire in a guide catheter and extending the first guidewire and the second guidewire to the vessel bifurcation. The method further includes positioning a first elongate medical device in the guide catheter over the first guidewire and extending the first elongate medical device to the vessel bifurcation. The method further includes positioning a support catheter comprising a tubular member including a longitudinal slit over the first and second guidewires by pushing a portion of the elongate medical device into a lumen defined by the tubular member. The method further includes advancing the first elongate medical device distally until a distal treatment structure of the first elongate medical device is positioned at the lesion. EXAMPLES

[0174] In Example 9, a method of treating a lesion in a blood vessel with an elongate medical device includes positioning a first guidewire within a guide catheter and extending the first guidewire distally past the lesion. The method further includes positioning a first elongate medical device within the guide catheter over the guidewire and extending the first elongate medical device until a distal treatment structure of the first elongate medical device is positioned proximal to the lesion. The method further includes positioning a support catheter comprising a tubular member including a longitudinal slit over a proximal or intermediate portion of the elongate medical device over the first guidewire by pushing the proximal or intermediate portion of the elongate medical device into a lumen defined by the tubular member. EXAMPLES

[0175] In Example 10, the method of Example 9 may be optionally configured to further include the steps of advancing the tubular member of the support catheter along the elongate medical device until the tubular member is positioned proximal to the treatment structure on the proximal side of the lesion, and advancing the treatment structure of the elongate medical device distally to or beyond the lesion. EXAMPLES

[0176] In Example 11, the method of Example 10 can optionally be configured to further include inflating a balloon of the treatment structure. EXAMPLES

[0177] In Example 12, the method of Example 11 can be optionally configured to further include removing the support catheter by withdrawing the tubular member proximally and peeling the tubular member away from the proximal or intermediate portion of the elongate medical device through the longitudinal slit. EXAMPLES

[0178] In Example 13, a guide extension catheter suitable for use with a guide catheter includes an elongate tubular member having or coupled to an angled proximal port, defining a longitudinal slit and a lumen, and having an outer diameter smaller than the lumen of the guide catheter. Additionally, the guide extension catheter includes a push member coupled eccentrically with respect to an axis of the tubular member and extending proximally of the tubular member for slidably positioning the tubular member within the guide catheter and partially beyond the distal end of the guide catheter. EXAMPLES

[0179] In Example 14, the guide extension catheter of Example 13 can be optionally configured to be tapered distally such that the outer diameter of the elongated tubular member is smaller at a distal portion of the elongated tubular member than at a proximal portion of the elongated tubular member. EXAMPLES

[0180] In Example 15, the guide extension catheter of Example 14 can be optionally configured such that the distal portion of the elongate tubular member includes a flexible tapered distal tip configured to fold back proximally therein. EXAMPLES

[0181] In Example 16, the guide extension catheter of any one or any combination of Examples 13-15 can optionally be configured such that the width of the longitudinal slit varies along the length of the longitudinal slit. EXAMPLES

[0182] In Example 17, the guide extension catheter of Example 16 can optionally be configured such that the longitudinal slit includes two or more cut-out portions, each having a width that is greater than the remainder of the longitudinal slit. EXAMPLES

[0183] In Example 18, the guide extension catheter of any one or any combination of Examples 13 to 17 can be optionally configured such that the push member includes a flattened portion embedded within at least a portion of the elongated tubular member. EXAMPLES

[0184] In Example 19, the guide extension catheter of any one or any combination of Examples 13-18 can optionally be configured such that the distal portion of the elongate tubular member is curved. EXAMPLES

[0185] In Example 20, the guide extension catheter of any one or any combination of Examples 13 to 19 can be optionally configured to include at least one stent-like metal frame, the elongated tubular member having a first interfitting component at a first end and a second interfitting component at a second end, the first interfitting component being complementary to the second interfitting component.

[0186] Concluding notes The above Detailed Description includes reference to the accompanying drawings, which form a part hereof. The Detailed Description should be read with reference to the drawings. The drawings illustrate specific embodiments in which the support catheters, loading components, and related methods of the present invention may be practiced. These embodiments are also referred to herein as "Examples."

[0187] Certain terms are used throughout this patent document to refer to particular features or components. As one of ordinary skill in the art will recognize, different people may refer to the same feature or component by different names. This patent document does not intend to distinguish between components or features that differ in name but not function.

[0188] For the following defined terms, certain definitions shall apply unless a different definition is provided elsewhere in this patent document. "a," "an," and "the" are used to include one or more than one of the term, regardless of other instances or uses of either "at least one" or "one or more than one." The term "or" is used to mean an open-ended or, such as "A or B" including "A but not B," "B but not A," and "A and B." All numerical values ​​are intended to be modified by the term "about," whether or not expressly indicated. In general, the term "about" refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the term "about" can include numbers that are rounded to the nearest significant figure. The recitation of numerical ranges by endpoints includes all numbers and subranges delimiting that range (e.g., 1 to 4 includes 1, 1.5, 1.75, 2, 2.3, 2.6, 2.9, etc., as well as 1 to 1.5, 1 to 2, 1 to 3, 2 to 3.5, 2 to 4, 3 to 4, etc.). The terms "patient" and "subject" are intended to include mammals, such as for human or veterinary use. The terms "distal" and "proximal" are used to refer to a location or direction relative to the treating clinician. "Distal" and "distally" refer to a location or direction away from the treating clinician. "Proximal" and "proximally" refer to a location or direction closer to or toward the treating clinician.

[0189] The scope of the present invention should be determined by reference to the claims, along with the full scope of equivalents to which such claims are entitled. Within the claims, the terms "comprises" and "wherein" are used as readily equivalent to the respective terms "comprises" and "wherein". Similarly, in the following claims, the terms "comprises" and "comprises" are open-ended, i.e., in a claim, a device, kit, or method that includes features or components other than those recited preceding such terms, is still deemed to comply with the scope of that claim. Furthermore, in the following claims, the terms "first", "second", "third", etc. are used merely as labels, and these terms are not intended to impose numerical requirements on their objects.

[0190] The Abstract is provided to enable the reader to quickly ascertain the nature of the technical disclosure of the present invention. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. [Explanation of symbols]

[0191] 302 Tubular members 304 Longitudinal slit 306, 308 Lip 310 Lumen

Claims

1. A device for use with a support catheter and at least one interventional device, comprising: a body including an elongated delivery channel sized to receive an interventional device and accommodate axial sliding movement of the interventional device, and an elongated loading structure sized to receive a tubular member of the support catheter and accommodate axial sliding movement of the support catheter; A device, comprising: a distal end of said elongated loading structure intersecting said elongated delivery channel along the length of said elongated delivery channel.

2. The elongated loading structure comprising a channel having a wedge-shaped protrusion extending along its length; The device of claim 1 , wherein the cross-sectional dimension of the wedge-shaped protrusion varies along its length.

3. The device of claim 1, wherein a distal portion of the elongated delivery channel is tapered to have a narrower width than a proximal portion of the elongated delivery channel.

4. A device for use with a support catheter and at least one interventional device, comprising: an elongated loading rod sized to be inserted into a tubular member of the support catheter, the elongated loading rod having a distal end configured to couple with a shaft of an interventional device; A device, wherein the distal end of the elongated loading rod has a larger dimension than the proximal end of the elongated loading rod.

5. The device of claim 4, further comprising a handle protruding from a side of the elongated loading rod and configured for user manipulation.

6. The device described in claim 4, wherein the distal end of the elongated loading rod defines a cylindrical portion configured to fasten one or more interventional devices together.

7. The elongated loading rod is two longitudinal components forming an interface therebetween, the two longitudinal components being configured to separate along their lengths, thereby creating a longitudinal gap between the two longitudinal components; a locking mechanism configured to reduce a width of the longitudinal gap by drawing the longitudinal components closer together along their lengths; The device of claim 4 further comprising:

8. A system for use with at least one interventional device, comprising: a support catheter for use with a guide catheter, the support catheter comprising an elongated tubular member having a longitudinal slit, a lumen, and an outer diameter smaller than the lumen of the guide catheter, the elongated tubular member further comprising or coupled to a proximal port; a push member eccentrically coupled to the axis of the elongated tubular member and extending proximally of the elongated tubular member to slidably position the elongated tubular member within the guide catheter and partially beyond the distal end of the guide catheter; a device configured to couple the support catheter to at least one interventional device; A system comprising:

9. An elongated delivery channel sized to receive the at least one interventional device and accommodate axial sliding of the at least one interventional device; an elongated loading structure sized to receive the elongated tubular member of the support catheter and accommodate axial sliding movement of the support catheter; A body including: The system of claim 8 , wherein a distal end of the elongated loading structure intersects the elongated delivery channel along a length of the elongated delivery channel.

10. An elongated loading rod sized to be inserted into the elongated tubular member of the support catheter, the elongated loading rod having a distal end configured to couple with a shaft of the at least one interventional device; The system of claim 8 , wherein the distal end of the elongate loading rod has a larger dimension than a proximal end of the elongate loading rod.

11. The system described in claim 8, wherein the outer diameter of the elongated tubular member tapers distally such that the outer diameter is smaller at a distal portion of the elongated tubular member than at a proximal portion of the elongated tubular member.

12. The system described in claim 8, wherein the width of the longitudinal slit varies along the length of the elongated tubular member.

13. The system described in claim 8, wherein the distal portion of the elongated tubular member has a flexible, tapered distal tip configured to fold back proximally into the lumen of the elongated tubular member.

14. The system described in claim 8, wherein the longitudinal slit has two or more cutout portions, each having a width greater than a non-cutout portion of the longitudinal slit.

15. The system of claim 8, wherein the push member comprises a flattened portion embedded in at least a portion of the elongated tubular member.

16. The system described in claim 8, wherein a distal portion of the elongated tubular member is curved.

17. The system described in claim 8, wherein the elongated tubular member comprises at least one stent-like metal frame having a first interfitting component at a first end and a second interfitting component at a second end, the first interfitting component being complementary to the second interfitting component.

18. The system described in claim 8, wherein the longitudinal slit is configured to allow the at least one interventional device to be exchanged inside or outside the lumen of the elongated tubular member.

19. The system described in claim 8, wherein the longitudinal slit includes a straight portion and at least one oblique or curved portion relative to the axis of the elongated tubular member, the at least one oblique or curved portion being located distal to the straight portion.

20. The system described in claim 8, wherein the longitudinal slit extends without penetrating 100% through the wall of the elongated tubular member such that the inner surface of the elongated tubular member is completely intact.

21. The system of claim 8, wherein the elongated tubular member includes a frame defined by a longitudinal spine and a plurality of protrusions extending from the longitudinal spine.

22. The system described in claim 8, wherein the elongated tubular member includes a snake-like frame defined by a series of longitudinal segments connected by transverse segments.

23. The system of claim 8, wherein the proximal port is defined and angled by a sloped wall, collar, or concave track extending from the push member to the fully cylindrical portion of the elongated tube member.

24. The system of claim 8, wherein the push member extends along substantially the entire length of the elongated tube member.

25. The system of claim 8, wherein the push member is coupled to the elongated tube member at a position opposite the position of the longitudinal slit.

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