Intravascular delivery system and method for percutaneous coronary intervention

Abstract

To provide a delivery system for percutaneous coronary intervention particularly adapted to intravascular balloon angioplasty and coronary stent delivery.SOLUTION: Provided is a guide catheter extension / pre-dilation system that includes an outer delivery sheath 36, an inner member 34 extending within the sheath 36, and a mechanism for engagement / disengagement of the inner member 34 relative to the sheath 36. The inner member 34 is configured with a tapered distal tip having a delivery microcatheter 46 and a pre-dilatation balloon member 44 attached to the tapered distal tip proximate the microcatheter 46. The outer delivery sheath 36 and inner member 34 may be modified for operation of different engagement / disengagement mechanisms. The delivery microcatheter 46 provides improved mobility of the balloon member 44 to the treatment site in an atraumatic, rapid, and convenient manner.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This PCT patent application claims the priority of U.S. Patent Application No. 16 / 793,120, filed on February 18, 2020, which is currently pending. U.S. Patent Application No. 16 / 793,120 is a Continuation - in - Part (CIP) of U.S. Patent Application No. 16 / 132,878, filed on September 17, 2018, which is currently pending. U.S. Patent Application No. 16 / 132,878 is a Continuation - in - Part (CIP) of U.S. Patent Application No. 15 / 899,603, filed on February 20, 2018, which is currently pending.

[0002] (Incorporation by Reference) U.S. Patent Applications No. 16 / 793,120, 16 / 132,878, and 15 / 899,603, which are currently pending, are hereby incorporated by reference into this specification.

[0003] The present invention relates to minimally invasive devices for use in therapy in the human vascular system, such as coronary arteries, and more particularly to a delivery system for percutaneous coronary intervention (PCI) that is particularly adapted for intravascular balloon angioplasty and coronary stent delivery, and which is enhanced by a pre - dilation guide catheter extension function.

[0004] Furthermore, the present invention relates to a medical device designed for non - invasive, simple, and rapid delivery of various interventional devices, such as pre - dilation balloons or stents, and for catheter exchange in the coronary arteries (or other blood vessels) within a patient's body, in order to facilitate percutaneous revascularization.

[0005] Furthermore, the present invention addresses an intravascular delivery system having a small, tapered, flexible distal tip that enables exceptional deliverability of an interventional device to a target, which is superior to conventional balloon angioplasty catheters, combined with substantially non - invasive maneuverability to a lesion site for treatment.

[0006] Furthermore, the present invention relates to an intravascular guide catheter extension / pre-dilation system that uses an inner member (interventional device delivery catheter subsystem) disposed at a predetermined position inside an outer member (outer delivery catheter subsystem). The inner member is formed with a distal coil-reinforced taper portion that interfaces with a slightly tapered distal end of the outer member. These are dimensioned to form a small outer profile and a substantially "seamless" transition at the interface between the distal ends of the outer member (outer catheter) and the inner member (inner catheter) at the transition point where the distal portion of the inner catheter engages or enters the outer member. This structure is extremely beneficial for smoothly passing the inner and outer members as a single unit along diseased blood vessels without damaging tissue.

[0007] Furthermore, the present invention relates to an intravascular guide catheter extension / pre-dilation system composed of an outer catheter (member) and an inner catheter (member) displaceable along the outer catheter inside the outer catheter. The distal tapered soft tip of the outer catheter is formed as an expandable flexible low durometer elastomer member having an inner diameter smaller than the outer diameter of the distal portion of the inner catheter in the region of engagement with the outer catheter in the contracted state. This configuration achieves a reversible elastic engagement between the outer and inner catheters at the distal end, which ensures that when the inner catheter is removed from the outer catheter, the expanded distal end of the outer catheter returns to its outer diameter in the contracted state, reducing (or eliminating) "fish-mouthing" at the distal junction of the outer and inner members as the system progresses through successive bends in the blood vessel.

[0008] Furthermore, the present invention relates to an intravascular guide catheter extension / pre-dilation system configured with outer and inner catheters displaceable relative to each other. The proximal end of the outer catheter has an inlet configuration that provides enhanced reinforcement, improved access for a stent in the middle of the shaft, prevention of stent embolization, improved flexibility, and improved flow rate of the contrast agent injection fluid.

[0009] Furthermore, the present invention relates to an intravascular guide catheter extension / pre-dilation system designed with a shaft intermediate interconnection (lock) mechanism that can be actuated / deactuated by a physician for either (1) controllably engaging inner and outer members so as to move integrally within a guide catheter along a guide wire, or (2) separating inner and outer catheters to retract an inner catheter from an outer member (catheter) as required in an intravascular procedure. The inner member can carry an intervention device (such as a pre-dilation balloon member or a stent) attached to its distal end reinforced with its tapered coil, and the lock mechanism provides a smooth and reversible engagement / separation procedure. Further, this reversible lock in the shaft intermediate prevents forward movement of the inner member relative to the outer member when advancing or retracting the system, ensuring that the position of the distal "seamless" transition of the inner and outer catheters remains basically fixed axially during movement of the subject system.

[0010] Furthermore, the present invention relates to an intravascular guide catheter extension / pre-dilation system configured with a tapered coil-reinforced shaft at its distal end for attaching and carrying a balloon member, providing "seamless" entry and smooth delivery of the balloon member integral with the coil-reinforced delivery sheath of the outer catheter to a desired treatment site.

[0011] Furthermore, the present invention addresses an intravascular guide catheter extension / pre-dilation system featuring an embodiment of a monorail microcatheter with a rapid exchange (RX) function for use with a short guide wire, and is configured with a coil-reinforced microcatheter where the distal tapered soft tip of the inner catheter provides additional kink resistance and "pushability" while still maintaining flexibility for moving through a tortuous vascular system.

Background Art

[0012] Coronary artery occlusive diseases or other diseases in the peripheral vascular system are often treated by balloon angioplasty and / or stent implantation. Advancing a revascularization device such as a balloon or stent delivery system within a blood vessel to the treatment site can be difficult for a physician when the blood vessel is tortuous and / or calcified.

[0013] Coronary stents are generally used in a procedure called percutaneous coronary intervention (PCI) and are placed in the coronary arteries that supply blood to the heart to keep the arteries open for the treatment of coronary heart disease. Stents have been shown to help improve blood flow in the coronary arteries and relieve chest pain, and to improve survival in cases of acute myocardial infarction.

[0014] Treatment of an occluded coronary artery with a stent follows substantially the same steps as other angioplasty procedures, but there are important differences. A stent in a compressed state attached to a balloon significantly reduces the flexibility of the balloon and makes it difficult to advance smoothly through the coronary artery. This can make it difficult or impossible to deliver the stent to the treatment site and there is a risk that the undeployed stent may detach from the delivery balloon.

[0015] Intravascular imaging can be used to assess the thickness and stiffness (calcification) of lesions that affect stent deliverability. A cardiologist uses this information to decide whether to treat a lesion with a stent and, if so, which type and size of stent to use. Stents, both bare metal stents and drug-eluting stents, are most often sold as a unit with the stent in a folded (pre-expanded) form attached outside a balloon catheter.

[0016] A physician can perform "direct stenting" in which the stent is advanced through the blood vessel to the lesion and expanded. However, it is common to pre-dilate the occlusion before delivering the stent to facilitate stent delivery in more difficult lesions.

[0017] Pre - dilation is achieved by passing a conventional balloon catheter through the lesion and inflating it to increase the diameter of the lesion. A balloon catheter is a type of "soft" catheter having an inflatable balloon at its tip that is used in catheter insertion procedures to expand narrow openings or passages in the body. After pre - dilation, the pre - dilation balloon is removed and a stent catheter is advanced through the blood vessel to the lesion, inflated, and left at the lesion site as a permanent implant to widen the blood vessel as a "scaffold".

[0018] The balloon catheters used in angioplasty have either an over - the - wire (OTW) or a rapid - exchange (RX) design. The balloon catheter is positioned by sliding it over a guide wire that can be threaded into the balloon catheter through a hub (in the case of over - the - wire variants) or an RX port (in the case of the rapid - exchange variant of the balloon catheter). In an over - the - wire type balloon catheter, a concentric lumen for passing the guide wire extends through the catheter from the proximal hub to the balloon, while in a rapid - exchange (RX) type balloon catheter, a lumen for the guide wire passage extends from the RX port through the interior of the catheter to the balloon, allowing the passage of the guide wire.

[0019] Revascularization devices typically use a guiding (or guide) catheter to deliver such a device to the site of treatment. Relying only on the guide catheter to "back - up" the advancement of a revascularization device into the coronary artery can be limited and difficult, especially when stents are deployed using a radial access guiding catheter.

[0020] To facilitate the delivery of a revascularization device to the target site, a guide catheter extension system has been designed and is used in cardiac surgery.

[0021] For example, a guide extension system such as "Guideliner (trademark)" is manufactured by Teleflex. This guide extension system is described in U.S. Patent No. 8,292,850 by Root et al. Root et al. (U.S. Patent No. 8,292,850) describe a coaxial guide catheter that is passed through the lumen of a guide catheter for use with an interventional cardiology device insertable into a branch artery branching from the aorta.

[0022] Root's coaxial guide catheter passes through the lumen of the guide catheter, extends beyond its distal end, and is inserted into the branch artery. Root uses a guide extension supported by a tapered inner catheter. The purpose of the inner catheter is to provide a non-traumatic tip to avoid vessel damage when advancing the guide extension into the proximal portion of the coronary vessel in order to provide additional "backup" support for the delivery of a stent or balloon.

[0023] Another guide extension system such as "Guidezilla (trademark)" is designed and manufactured by Boston Scientific. This guide extension system is described in U.S. Patent No. 9,764,118 by Anderson et al. Anderson's guide extension system uses a push member having a proximal portion with proximal rigidity, a distal portion with a distal rigidity different from the proximal rigidity, and a transition portion providing a smooth transition between the proximal portion and the distal portion. A distal tubular member is attached to the push member and has an outer diameter larger than the outer diameter of the push member.

[0024] U.S. Patent Application Publication No. 2017 / 0028178 by Ho describes a guide extension system that uses a slit catheter that can expand upon insertion of a balloon or stent delivery system. Further, Ho's guide extension uses a rigid push rod to assist in the delivery of the guide extension to the treatment site.

[0025] The "Guideliner (trademark)" and "Guidezilla (trademark)" systems, as well as Ho's system, support the concept of partially advancing a guide extension system through a guiding catheter into the coronary artery to achieve additional "backup" support for delivering a balloon dilation catheter and / or a stent delivery catheter to the intended treatment site.

[0026] The function of these guide extensions is to enable getting closer to the lesion in order to provide additional support when crossing the lesion to be treated with the interventional device. However, despite the additional support, it can still be difficult or nearly impossible for a pre-dilation balloon catheter or a stent delivery system to pass through the lesion to be treated due to fibrosis, calcification, previous stent struts within the lumen, and / or the angulated shape of the lesion site.

[0027] One of the limitations of currently used guide extension devices is that they use a relatively blunt large-diameter cylindrical distal end. Due to the relatively large outer shape of the distal edge, the deliverability of the guide extension is often limited and can only be advanced up to the proximal or middle part of the coronary artery being treated. Even after balloon pre-dilation of the lesion, it is extremely rare, if not impossible, to deliver the guide extension to the actual lesion being treated with angioplasty or stent implantation. These "blunt-tipped" tubular guide extension devices do not work well relatively frequently and can cause serious dissociation complications. Published data indicate that "blunt-tipped" tubular guide extension systems do not work well in up to 20% of cases and have the potential to cause severe coronary artery dissociation in approximately 3% of cases.

[0028] U.S. Patent Application Publication No. 2011 / 0301502 by Gill describes a catheter having a longitudinal extension that enables the diameter of the positioning device to be smaller than that of the stent delivery system. However, Gill's device does not envision an inner catheter that would enable easy and non-damaging crossing of the lesion being treated. Gill's system simply serves as a cover for the stent delivery system and can be removed after advancing the stent delivery system due to its longitudinal extension.

[0029] The concept of a tapered component inside the guide extension catheter is seen in Root's device, but prior art systems use extremely short tapers and do not envision the taper as an elongated integral member of the entire system, nor do they envision attaching a pre-expansion balloon to the tapered delivery microcatheter that is brought to the target treatment area. Furthermore, the prior art does not envision a substantially "step-free" boundary between the inner catheter and the outer guide extension inside the blood vessel, and does not envision reversibly fitting or locking the inner and outer catheter members to easily move the entire system as one integral device.

[0030] Root or other prior art systems do not describe, anticipate, or envision a balloon (and / or stent) delivery system having a very small outer profile with an elongated tip that would be beneficial in achieving coaxial delivery of a guide catheter extension / balloon system to and beyond the target lesion. Such embodiments have not been commercially available to date, and the description of the inner device with a tapered tip is only intended as a mechanism for bringing the blunt tip of the guide catheter extension proximally from the guiding catheter, and is never intended as a mechanism for delivering a balloon (and / or stent) to and beyond the target treatment area within the blood vessel, nor do they envision that the integral nature of the inner and outer members and the "step-free" interconnection would enable passage of the outer delivery "sheath" member across the target lesion.

[0031] Accordingly, an apparatus and method that enable the distal portion of a tubular guide extension system to reach a lesion to be treated and, ideally, to be advanced beyond the lesion to be treated are considered to have significant advantages compared to conventional guide extension devices such as "Guideliner (trademark)" (Teleflex) or "Guidezilla (trademark)" (Boston Scientific).

[0032] Conventional balloon catheters (over-the-wire or rapid-exchange) are not integrated with an outer delivery sheath and do not use a tapered delivery microcatheter at the distal end of the catheter to which an intervention device (e.g., a balloon or stent) is fixed to reach the lesion site within the blood vessel without causing injury and to further advance beyond the lesion site. Further, none of the conventional balloon catheters operate to enable the conventional balloon catheter and the outer delivery sheath to be moved integrally as a single unit, and are not interconnected to the outer delivery sheath (guide catheter extension subsystem) via an interconnection mechanism that is deactivated to prevent forward displacement of the balloon catheter relative to the outer delivery sheath while allowing the balloon catheter to be retracted from the outer delivery sheath.

[0033] It is highly desirable and considered efficient to provide an intravascular delivery system that can deliver an intervention device (e.g., a pre-dilation balloon) to a lesion and further beyond the lesion in a substantially non-invasive and convenient manner, together with a guide catheter extension subsystem (such as an outer delivery sheath).

[0034] Furthermore, it is highly desirable to provide an intravascular delivery system having an outer catheter and an inner catheter, both featuring an enhanced distal end with a small tapered distal tip shape having a "seamless" distal boundary, to ensure that the system can be advanced to the lesion for treatment without causing injury.

[0035] In addition, it is considered desirable to facilitate percutaneous revascularization procedures by using a balloon attached to the coil-reinforced tapered distal tip of an inner balloon catheter housed within the outer delivery sheath of an outer catheter. The inner balloon catheter includes a distal elongated tapered coil-reinforced microcatheter at its tapered distal tip for carrying an intervention device (pre-dilation balloon and / or stent) to and past the lesion to be treated. This is considered to represent a significant improvement over conventional guide catheter extension and pre-dilation systems.

Prior Art Documents

Patent Documents

[0036]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

[0037] Accordingly, an object of the present invention is to provide a medical device for intravascular application that can deliver an intervention device (such as a balloon or stent) to an occlusive lesion in a coronary artery and further past such a lesion in an efficient and minimally traumatic manner.

[0038] Another object of the present invention is to be useful for achieving the "transversality" of a pre - dilation balloon (or other interventional device), having a small outer shape that improves the efficient and safe distal delivery of a guide extension device, and having a coaxial, highly flexible delivery catheter device with an outer catheter and an inner catheter that interface with each other at the distal end in a "seamless" manner, to provide an intravascular delivery system.

[0039] A further object of the present invention is to use a highly flexible coil - reinforced distal - tapered elongated micro - catheter tip to deliver a pre - dilation balloon (or another interventional device) into and / or past a target lesion in a diseased human coronary artery being treated by angioplasty (or stenting).

[0040] A further object of the present invention is to provide a guide catheter extension / pre - dilation system that uses an outer catheter (outer delivery sheath subsystem) and an inner catheter (interventional device delivery subsystem) that is removably connected and housed inside the outer sheath of the outer catheter, both of which are deliverable into or beyond a lesion area for treatment within a blood vessel, and the inner catheter having at its distal end a delivery - tapered micro - catheter to which a pre - dilation balloon member (or other interventional device) that slides substantially non - invasively along a guide wire is attached.

[0041] A further object of the present invention is to provide a guide catheter extension subsystem (outer member) integrated with a pre - dilation balloon (or another intervention device) subsystem (inner member), wherein the outer member and the inner member are coupled to each other (via a locking mechanism) so as to be displaced together (as an "entire system") along a guide wire to a lesion site. After the pre - dilation procedure, the guide catheter extension subsystem (configured with an outer delivery sheath) can be detached from the inner member and advanced past the lesion as needed. Subsequently, the inner member (intervention device delivery subsystem) can be withdrawn. If necessary for the surgery, the outer delivery sheath of the outer member can remain within the guide catheter to enhance the deliverability of a stent (or other intervention device) at the lesion site inside the outer delivery sheath. Thereafter, the outer delivery sheath can be withdrawn after the stent (or other intervention device) has been delivered to the lesion and deployed for final treatment.

[0042] Furthermore, an object of the present invention is to provide a guide catheter extension / pre - dilation system having an operably coupled "locking mechanism" between the inner member and the outer member (outer sheath) so as to integrally pass both the inner member and the outer member as a single unit to conveniently and safely deliver a pre - dilation balloon (or other intervention device) and the outer sheath to and even past the treatment site.

[0043] A further object of the present invention is to provide a guide extension system configured with a pre - dilation balloon (or other intervention device) delivery catheter capable of delivering the interior of the vascular structure to the treatment site in a non - invasive manner to achieve easy passage of the balloon (or other intervention device) and the guide extension system and to speed up cardiac surgery, enabling percutaneous coronary intervention with a lower radiation dose exposure than would be achieved using conventional systems and having the additional advantage that there is substantially no risk of stent embolization or drug loss from the stent delivery system (due to drug - eluting stents).

[0044] A further object of the present invention is to provide a coaxial inner and outer catheter which are displaceable relative to each other, still increasingly flexible, reinforced by coil reinforcement along its length, and capable of achieving improved contrast agent injection flow rate and embolism prevention, and which elastically stretches the tapered distal end of the outer catheter to form a strong contact with the distal portion of the inner catheter and a substantially step-free (smooth) outer surface at the interface between the inner catheter and the outer catheter. An intravascular guide catheter extension / pre-dilation system is provided.

[0045] The present system and method address an intravascular delivery system configured to be controllably displaced along a guide wire within a target vessel. The system is formed with a proximal portion, a distal portion, and an intermediate portion located between the proximal portion and the intermediate portion. The system includes an outer member formed by a flexible, substantially cylindrically contoured elongated outer delivery sheath defining a sheath lumen having a proximal end and a distal end. The outer delivery sheath extends between the intermediate portion and the distal portion and is configured with a tapered outer tip at the distal end of the sheath lumen. The tapered outer tip of the outer member located at the distal end of the outer delivery sheath is configured with a wall extending in a cylindrical aspect between a distal edge and a proximal edge of the tapered outer tip. The wall of the tapered outer tip has an inner diameter and an outer diameter. The inner diameter and the outer diameter of the wall of the tapered outer tip gradually decrease in dimension from the proximal edge to the distal edge of the tapered outer tip. The proximal (wire or hypo tube) element (push or pull) connected to the tubular structure of the outer member may have a small outer shape and be "flexible" (not "rigid") to improve the compatibility of the guide catheter inside and to allow a smaller outer shape than the rigid "push" element in conventional guide extension catheters such as Root. This is made possible by the "pushability" of the "system as a whole" achieved through a locked integral connection between the outer catheter (having a hypo tube push / pull element) and the inner catheter (guide extension tube).

[0046] The system further includes an inner member (inner catheter) having an elongated body defining an internal channel extending along a longitudinal axis. The inner member extends internally along the sheath lumen of an outer member (outer catheter) in a controllable relationship with the outer delivery sheath. The elongated body of the inner member has a tapered distal portion, and the tapered distal portion is configured to include a tapered delivery catheter having an outer diameter and an elongated body of a predetermined length. The tapered delivery catheter of the inner member is displaceable beyond the distal end of the outer sheath. It is important that the inner diameter of the wall of the tapered outer tip of the outer member is smaller than the outer diameter of the tapered distal portion of the inner member in the region where these two elements form a distal junction.

[0047] An interconnection mechanism is operably coupled between the inner member and the outer member and is controllably actuated to operate the guide catheter extension / pre - dilation subsystem in an engagement mode of operation or a separation mode of operation. In the engagement mode of operation, the inner and outer members of the guide catheter extension subsystem engage for controllable common displacement along a guide wire. This enables an improvement in the "pushability" of the system (having an outer member connected and locked to the inner member), even if the connected pusher (push / pull element) of the outer member has a small outer profile and is flexible (as flexible as or more flexible than the outer tubular sheath of the outer catheter). In the separation mode of operation, the inner member and the outer member are separated to retract the inner member from the outer member after a pre - dilation procedure or stent delivery.

[0048] The distal portion of the inner member interfaces on its outer surface with the inner surface of the tapered outer tip of the sheath lumen. The dimensional transition between the outer diameter of the outer tip of the sheath lumen and the outer diameter of the distal tip of the inner member forms a boundary transition with substantially no step between them.

[0049] The tapered outer tip of the outer member has a configuration that can expand elastically. At its proximal end (also referred to herein as the shaft intermediate portion of the outer member), the outer sheath is configured with an inlet opening whose perimeter exceeds the perimeter of the tubular body of the outer sheath. In some embodiments, the inlet opening at the proximal end of the outer sheath is funnel-shaped.

[0050] The outer sheath is preferably reinforced along its length. The outer member includes a distal soft tip encapsulation material that wraps around the reinforced sheath of the outer member at its distal end. The distal soft tip encapsulation material is a flexible low durometer elastomeric material having a durometer value with a gradient that increases from the distal end to the proximal end of the sheath.

[0051] The outer member further includes a distal lubricating liner sandwiched between the outer surface of the outer sheath and the inner surface of the distal soft tip encapsulation material.

[0052] The delivery catheter is preferably a microcatheter. The microcatheter is formed of a flexible material and can have different flexibilities along its length, and the flexibility of the microcatheter increases towards its distal end.

[0053] A balloon catheter is attached to the tapered distal portion of the inner member in proximity to the tapered delivery microcatheter, and an inflation lumen extends within the inner member between the proximal and distal balloon members, providing a fluid passage between an external balloon inflation system and the balloon member. The balloon member can be in an inflated or deflated state. In the deflated state, the balloon member is displaced within the blood vessel. The balloon member is controllably deformed into an inflated configuration after being at least aligned with the treatment site for a pre-dilation procedure.

[0054] The elongate body of the inner member and the microcatheter are reinforced with coils along their lengths.

[0055] The pusher / puller element of the outer catheter configured to have a flat portion at its distal end is fixed to the proximal end of the outer sheath of the outer catheter. Preferably, the pusher / puller of the outer member is configured to have a channel that extends along its length and communicates with the sheath lumen to prevent plugging. This proximal (push and pull) element connected to the outer sheath tubular structure of the outer catheter may have a small outer shape and be "flexible" (not "rigid") to allow for better fit inside the guiding catheter and a smaller outer shape than the rigid "push" element in conventional guide extension catheters (such as Root).

[0056] The interconnect mechanism can include a snap-fit locking mechanism configured with a proximal coupler disposed at the proximal end of the sheath of the outer member (catheter) and a cooperating element disposed on the outer surface of the elongated body of the inner member (catheter). The proximal coupler can include a distal solid ring and an intermediate split ring disposed at a predetermined distance from the solid ring, while the cooperating member includes a member selected from the group including a shift intermediate lock ring, a square annular ring, a snap-fit cage, and other similar members. The cooperating member is attached to the outer surface of the elongated body of the inner member. When the cooperating member engages and locks in a snap-fit manner between the distal solid ring and the intermediate split ring, a locking engagement between the outer member and the inner member is achieved. The pusher / puller element and coupler of the outer catheter are made of a shape memory metal (e.g., nitinol, etc.) to prevent deformation during forward or reverse movement of the outer member and to prevent deformation of the shaft intermediate coupler (also referred to herein as the proximal coupler) when a stent or other device passes through the shaft intermediate portion of the outer catheter.

[0057] The proximal coupler further includes, at its proximal end, a proximal inclined split ring that reinforces the funnel-shaped proximal inlet of the outer member and prevents damage or permanent deformation of the funnel-shaped proximal inlet caused by displacement of the inner member or stent delivery system at the funnel inlet. The coupler and the shaft intermediate inlet can have an inlet opening (or "mouth") that is larger around its perimeter than the perimeter of the flexible tubular outer sheath structure of the outer member.

[0058] The vascular system of interest further includes a guidewire that can be advanced at least into the vasculature of the subject up to the treatment site, and the guide catheter extension subsystem is configured to be displaceable controllably along the guidewire. In one embodiment of the system, an elastic outer jacket wraps the inner member at least at its proximal end and wraps the pusher / puller of the inner member at least along its distal end. The proximal end of the inner member is connected to the pusher / puller by fusing the elastic outer jacket to the length of the proximal end of the inner member and snugly supporting the pusher / puller of the inner member within the elastic outer jacket.

[0059] The push-pull element (or its outer jacket) of the outer catheter may be color-coded to have a distinguishing color for distinguishing from the push-pull element of the inner catheter and from the normal gray or silver color of a coronary guidewire. Alternatively, the elastic outer jacket of the inner member may be color-coded to distinguish the pusher / puller of the inner member from the colors of the other elements of the system of interest for the convenience of the surgeon.

[0060] These and other objects and advantages of the present invention will become apparent to those skilled in the art by considering the detailed description of the present invention in conjunction with the patent drawings.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0062] In FIGS. 1 to 24B, a target intravascular delivery system 10 including a guide catheter extension subsystem (also referred to herein as an outer catheter or an outer member) and an intervention device delivery subsystem (also referred to herein as an inner catheter or an inner member) that cooperate under the control of a surgeon during heart surgery is shown. The intervention device delivery subsystem can be used for delivering various heart intervention devices. However, in one of the embodiments, by way of example only and without limiting the scope of the present invention to this specific embodiment, the target intervention device delivery subsystem will be further described as being configured for delivering a balloon member for performing a pre-dilation procedure.

[0063] In an exemplary embodiment described herein, the subject system 10 can be referred to as a guide catheter extension / pre - dilation system that can be used in heart surgery, along with a guide wire 12 and a guide catheter 14, herein. As shown in FIG. 1, in the initial stage of heart surgery, a guide wire (GW) 12 is moved into a blood vessel 16 by a surgeon. The guide catheter 14 is advanced through the blood vessel 16 (e.g., aorta, etc.) along the guide wire 12 to a position adjacent to the inlet 18 of the coronary artery 20. The guide wire 12 can be used to guide the guide catheter 14 in heart surgery, and then the subject guide catheter extension / pre - dilation system 10 (inside the guide catheter 14) can be extended towards a target position 22 within the artery 20 as detailed in the following paragraphs.

[0064] As shown in FIGS. 2A - 2C, the subject guide catheter extension / pre - dilation system 10 includes a balloon catheter subsystem 34 (also referred to herein as the inner catheter, inner member, or pre - dilation sub - assembly) and a guide catheter extension subsystem 36 (also referred to herein as the outer catheter). The inner catheter 34 can interact with the outer catheter 36 and can be engaged with or disengaged from the outer catheter 36 as required in heart surgery.

[0065] The subject system 10 includes a proximal portion 38, a distal portion 40, and an intermediate portion 42 that extends between the proximal portion 38 and the distal portion 40 and interconnects the proximal portion 38 and the distal portion 40. A pre - dilation balloon member 44 is held at the distal portion 40 of the inner catheter 34. Further, the distal portion 40 of the inner catheter 34 can be configured to include an elongate tapered micro - catheter 46 as detailed in the following paragraphs.

[0066] The subject guide extension / pre - dilation system 10 is advanced within the lumen (inner channel) 48 of the guide catheter 14 as shown in FIG. 1. To reliably reach the target position 22 and, in some cases, pass through the target position 22, the subject guide extension / pre - dilation system 10 is advanced deeply into the coronary artery 20 past the distal end 50 of the guide catheter 14 and through the guide catheter 14. The subject system 10 provides proper access to the pre - dilation balloon 44 to the target position 22 by extending past the distal end 50 of the guide catheter 14, stabilizes the positioning of the guide catheter 14 by extending past the inlet 18 of the coronary artery 20, and enables improved access of the subject system 10 to the coronary artery 20 and the target site 22.

[0067] As shown in FIGS. 1, 2A and 2B, 3C and 3D, 4, 5A - 5C, and 6A, the guide wire 12 extends through the interior of the guide catheter extension / pre - dilation system 10 and exits the system 10 with the distal end of the GW12 past the outermost end 52 of the distal portion 40 and the proximal end of the GW12 in the intermediate portion 42.

[0068] During operation, the inner catheter 34 and the outer catheter 36 are connected to each other and advanced (as a single unit) along the guide wire 12 inside the guide catheter 14 disposed within the blood vessel 16, extending past the distal end 50 of the guide catheter 14 to reach the target lesion site 22. Once the subject balloon catheter subsystem (inner member) 34 reaches the lesion site 22 and the balloon member 44 is aligned and positioned at the lesion site 22, the intended pre - dilation procedure can be performed. Once pre - dilation is performed, the outer catheter (also referred to herein as the outer member) 36 can be advanced across the lesion as an integral unit with the inner catheter (also referred to herein as the inner member) 34, and then the inner catheter 34 can be detached from the outer catheter 36 to withdraw the inner catheter from the outer catheter.

[0069] Alternatively, after performing the pre-dilation treatment, the inner catheter 34 can be detached from the outer catheter 36, while the outer catheter 36 can be advanced across the dilated lesion. Additionally, the outer catheter 36 may be left near the lesion after performing pre-dilation and removing the inner catheter 34.

[0070] In either situation, the outer member (catheter) 36 left near the lesion after pre-dilation can be used to deliver the stent inside the outer member (catheter) 36 to the lesion site. When the stent is placed (deployed) at the lesion site, the outer member 36 is removed from the guide catheter 14.

[0071] As presented in further paragraphs, in the subject system, forward displacement of the inner catheter 34 inside the outer catheter 36 is prevented. Exclusively, rearward displacement or displacement for removal of the inner member 34 relative to the outer member 36 is made possible to support the retraction of the inner member from the outer member after pre-dilation of the lesion.

[0072] Referring to FIGS. 2A - 2C, the proximal portion 38 of the subject guide extension / pre-dilation system 10 is represented by the balloon inflation hub 56 of the inner member 34 (best shown in FIG. 2B) and the proximal end 58 of the outer member 36.

[0073] Referring to FIGS. 2B, 3A - 3D, 4, and 5C, the inner member (also referred to herein as the balloon catheter subsystem or pre-dilation balloon delivery subsystem) 34 is configured to include an internal inflation channel 60 that extends between the inflation hub 56 and the pre-dilation balloon member 44. The internal inflation channel 60 functions as a passage for inflation air between the balloon inflation system 62 (schematically shown in FIG. 2B) and the balloon member 44 for the controlled inflation / deflation of the balloon member 44 as defined by cardiac surgery.

[0074] The inner inflation channel 60 is formed by an inflation lumen hypo-tube 64 and an inflation lumen distal shaft 66 that are overlapped and interconnected with each other in a manner that does not leak fluid.

[0075] The inflation hub 56 located at the proximal end 68 of the inner member 34 is configured to include an internal conical channel 70 that is connected to a balloon inflation system 62 (as schematically shown in FIG. 2B) by a proximal opening 72.

[0076] The balloon inflation system 62 may be a manual or automatic system. In a preferred automatic embodiment, the balloon inflation system 62 includes an electronic subsystem, a pneumatic subsystem, and control software having a corresponding user interface. The electronic subsystem supplies power to a solenoid pressure valve (connected to the balloon inflation hub 56 with respect to fluid) to control the pressurization / de-pressurization of the balloon member 44 by the flow of fluid or air under the control of the control software.

[0077] As shown in FIG. 2B, the internal conical channel 70 of the balloon inflation hub 56 is configured to include a distal opening 74 connected to the inflation lumen hypo-tube 64. The proximal end of the inflation lumen hypo-tube 64 is connected to the distal opening 74 of the internal conical channel 70 of the balloon inflation hub 56 in a manner that does not leak fluid to support the passage of inflation air between the balloon member 44 and the inflation system 62.

[0078] The inflation lumen hypo-tube 64 extends through the entire length of the proximal portion 38 and a part of the intermediate portion 42 of the target system 10 as shown in FIGS. 2B and 4, and ends at a distal end 78 in the distal portion 40.

[0079] As shown in FIG. 2B, a flexible serrated member 80 is provided at the proximal end 76 of the inflation lumen hypo-tube 64 connected to the distal end 82 of the balloon inflation hub 56. The serrated flexible member 80 supports the proximal end 76 of the inflation lumen hypo-tube 64 and provides flexible bending of the structure when operated by a surgeon.

[0080] As shown in FIGS. 2A-2C, 3A-3D, 4, and 5C, the inflation lumen distal shaft 66 extends between the proximal portion 38 along the intermediate portion 42 and ends at the distal portion 40. FIG. 3A shows in detail the junction between the inflation lumen hypo-tube 64 and the inflation lumen distal shaft 66. The inflation lumen hypo-tube 64 does not extend all the way through the inner member 34 and ends at the distal end 78 (as shown in FIGS. 2B and 4).

[0081] Referring to FIGS. 3B-3D, the inflation lumen hypo-tube 64 has a tapered distal portion 90 coaxially enclosed by the wall of the inflation lumen distal shaft 66. Thus, the inflation lumen hypo-tube 64, in cooperation with the inflation lumen distal shaft 66, provides a sealed fluid communication between the balloon inflation system 62 and the inner chamber 92 of the balloon member 44 for the controlled inflation / deflation of the balloon member 44 as required in cardiac surgery, as shown in FIGS. 5A-5C.

[0082] FIGS. 2B and 3C and 3D show that the inflation lumen distal shaft 66 is configured with a rapid exchange (RX) guide wire (GW) port 94 where the GW lumen 96 begins at its proximal end 98. The GW lumen 96 extends between the RX GW port 94 inside the inflation lumen distal shaft 66 over the entire length of the distal portion 40 of the inner catheter 34. The GW lumen 96 forms an internal channel having a proximal end 98 corresponding to the RX GW port 94 and a distal end 100 corresponding to the outermost distal end 52 of the distal portion 40 of the inner member 34. As shown in FIGS. 6A and 6B, at the distal portion 40, the GW lumen 96 extends beyond the distal end 102 of the inflation lumen distal shaft 66. The distal end 100 of the GW lumen 96 constitutes a gradually tapered portion 104 that may be in the form of a delivery microcatheter 46.

[0083] Referring to FIGS. 2A and 2B, FIGS. 5A-5C, FIGS. 6A and 6B, and FIGS. 24A and 24B, an inner catheter (also referred to herein as a balloon catheter subsystem) 34 is configured to include a tapered distal portion (also referred to herein as a tapered distal tip) 162 at a distal portion 40. The tapered distal portion 162 includes a pre-expansion balloon member 44 fixed to the tapered distal portion 162 in proximity to the microcatheter 46. The pre-expansion balloon member 44 is fixed to the tapered distal portion (tip) 162 of the inner member to support a pre-expansion / stent implantation procedure as required for treating a patient's heart.

[0084] The balloon member 44 has a proximal portion 112 and a distal portion 114. The balloon member 44 has its proximal portion 112 coupled to the distal end 102 of the inflation lumen distal shaft 66 and its distal portion 114 coupled to the outer surface of the microcatheter 46 and is attached (fixed) to the distal portion 40 in proximity to the advancing microcatheter 46.

[0085] As shown in FIGS. 5A-5C, the pre-expansion balloon 44 is attached at its proximal portion 112 to the proximal portion 204 of the distal tip 162 arranged adjacent to the outer distal tip 164 of the sheath 120 and at its distal portion 114 to the distal end 166 of the distal portion (tip) 162 of the inner member 34.

[0086] The balloon member 44 can intermittently assume a contracted (folded) configuration and an expanded (extended) configuration. The contracted (folded) configuration is used during insertion and / or withdrawal of the subject system into the blood vessel. The balloon is expanded (extended) when at a predetermined location (target site 22) to expand the blood vessel and compress plaque for a pre-dilation procedure or a stent implantation procedure (when a stent is delivered to the treatment site on the balloon). When expanded, the balloon 44 assumes the inflated / open configuration shown in FIGS. 2A and 2B, FIGS. 5A, 5C, FIGS. 6A and 6B, and FIGS. 24A and 24B for pre-dilation of the diseased blood vessel. When contracted, the balloon member 44 assumes the contracted configuration shown in FIG. 5B.

[0087] The balloon 44 can have a smooth surface or a "chocolate" configuration. The "chocolate" balloon catheter is an over-the-wire type balloon dilation catheter having a braided shaft and a non-traumatic tapered tip. The balloon is constrained by a nitinol structure that creates small "pillows" and grooves in the balloon when expanded.

[0088] Referring now to FIGS. 2A, 2C, FIGS. 5A-5C, FIGS. 7, 8A and 8B, FIGS. 9A, 9C, and 9D, FIGS. 10A-10G, FIGS. 11C, 12B and 12C, FIGS. 13A and 13B, FIG. 14B, FIGS. 15A-15D, FIGS. 16A and 16B, FIGS. 17A and 17B, FIGS. 18A and 18B, FIG. 19B, FIGS. 20A and 20B, FIG. 21, and FIGS. 24A and 24B, the outer catheter (also referred to as the guide catheter extension subsystem) 36 is formed with a cylindrical outer delivery sheath 120 having an internal channel 122 extending therethrough along its length. A coupler mechanism 130 is formed at the proximal end 132 of the cylindrical sheath 120 in a surrounding relationship therewith.

[0089] At the proximal end 58, the outer catheter 36 includes an outer member pusher (also referred to herein as a pusher / puller) 134, and the outer member pusher 134 can be a solid wire having, in one embodiment, a circular wire proximal portion 136 and a flattened distal portion 138 that can be welded or otherwise fixedly attached to the proximal end 132 of the sheath 130, as shown in FIGS. 10B - 10G, FIGS. 11A - 11C, FIGS. 12A - 12C, FIGS. 13A and 13B, FIGS. 14A and 14B, FIGS. 15A - 15D, FIGS. 16A and 16B, FIGS. 17A and 17B, FIGS. 18A and 18B, FIG. 19B, and FIG. 22. In another embodiment, the push - pull element 134 can be composed of a hypodermic tube.

[0090] Alternatively, a circular pusher wire can be welded to a flat wire, and the flat wire is welded to the proximal end 132 of the sheath 120 or otherwise firmly fixed.

[0091] In yet another alternative embodiment of the outer member 36, a circular wire can be welded or otherwise firmly fixed to two flat wires, and then the two flat wires are welded to the proximal end 132 of the sheath 120 or otherwise firmly fixed.

[0092] The flat outer shape of the pusher - wire portion ensures that when the inner member 34 is inserted into the outer member (catheter) 36, the pusher wire does not create an obstacle to the rotation or longitudinal movement of the inner catheter 34 inside the proximal coupler 130 and sheath 120 of the outer member 36 as required in surgery. The proximal push - pull element 134 moves forward or backward with the outer tubular sheath 120 and is preferably flexible (not rigid). The pusher / puller 134 can be flexible (not rigid), and its flexibility along its longitudinal axis is comparable to or exceeds the flexibility of the tubular outer delivery sheath 120 of the outer catheter 36.

[0093] For a surgeon performing a coronary intervention procedure, it is convenient for the outer member 36 to be manipulated to position the outer delivery sheath 120 together with the balloon delivery subsystem 34 at a desired position relative to the lesion 22 in the diseased blood vessel. Thus, the pusher 134 of the outer catheter can be provided with a proximal handle 140 as shown in FIG. 10F at its proximal end.

[0094] The proximal push / pull element 134 (composed of a wire or a hypo tube) connected to the tubular structure 120 of the outer member has a small outer shape and is flexible (not "rigid"), thereby improving the compatibility of the guide catheter inside and achieving a smaller outer shape than the rigid "push" element in a conventional guide extension catheter (such as Root). This is made possible due to the "pushability" of the "overall system" achieved through a locked and integral connection between the outer catheter (having a hypo tube push element) and the inner catheter (guide extension tube).

[0095] Furthermore, the inner catheter (inner member) 34 can be provided with a pusher (also referred to herein as a pusher / puller) 142 (shown in FIG. 2A) of the inner member that may be attached to the inflation hub 56 to facilitate the withdrawal of the inner member 34 from the outer member 36 as required in various stages of cardiac surgery and in coronary intervention procedures, and to control the engagement / disengagement therebetween. The pusher / puller 142 of the inner member can be formed with a handle of the pusher / puller of the inner member to be convenient for the surgeon performing the procedure.

[0096] The handles of the pushers of the inner and outer members can be configured with a mechanism (detailed in U.S. Patent Application No. 15 / 899,603 incorporated herein by reference) that enables an additional releasable lock between the inner and outer members to enhance the integral cooperation of the inner and outer members in the engagement operation mode.

[0097] The inner member 34 may be either an over-the-wire configuration or an RX configuration. In one of the embodiments detailed herein, the guide wire 12, as shown in FIGS. 3C and 3D and FIG. 4, extends through an RX GW port 94 formed at the proximal end of a tubular expandable lumen distal shaft 66 and into an internal channel 146 of a GW lumen 96, and extends along the internal channel 146 of the GW lumen 96. In the distal portion 40 of the subject system 10, the guide wire 12, as shown in FIGS. 2A and 2B, FIGS. 5A and 5B, and FIGS. 6A and 6B, extends within the GW lumen along a delivery tapered microcatheter 46 (at a tapered portion 104) and exits from the distal end 100 of the GW lumen 96 at the outermost end 52 of the inner member 34.

[0098] The outer delivery sheath 120 of the outer member 36 is fabricated from a flexible cylindrical tubular body 150 that extends substantially over the length of the intermediate portion 42 of the subject system 10. By operating the outer member pusher 134, the surgeon actuates the integral forward movement of the outer delivery sheath 120 and the inner member 34 along the guide catheter 14. When a pre-dilation procedure is performed (as detailed in a further paragraph), the surgeon controls the required linear rearward displacement of the inner member 34 relative to the sheath 120 of the outer member 36 by operating the outer member pusher 134 and / or the inner member pusher 142.

[0099] As shown in FIGS. 8A-8B and FIGS. 9A-9D, the boundary between the outer distal tip 164 of the sheath 120 and the distal tip 162 of the inner member 34 facilitates displacement of the distal tip 162 of the inner member 34 relative to the outer distal tip 164 of the sheath 120 and, essentially, facilitates displacement of the distal tip 162 relative to the outer distal tip 164 of the sheath 120 as required in cardiac surgery.

[0100] The distal end 160 of the sheath 120, as well as the outer distal tip 164, are formed from a flexible material that allows the distal tip 162 of the inner member 34 to be easily retracted therethrough. A flat spiral coil can be used for the distal end 160 and the outer distal tip 164 of the sheath 120.

[0101] At its proximal end 132, the sheath 120 of the outer catheter 36 is configured to include an inlet "opening" (or "mouth") 210 whose outer periphery exceeds the outer periphery of the outer member flexible tubular sheath 120, as shown in FIGS. 10A-10G. The inlet 210 (also referred to herein as the "mouth") to the internal channel 122 of the sheath 120 can be configured with various modifications. For example, as shown in FIG. 10A, the inlet 210 has an eccentric opening (as shown in FIG. 10A), or is contoured with a concentric obtuse angle (as shown in FIGS. 10B and 10C), or has a concentric inclination (as shown in FIGS. 10D and 10E), or has a funnel shape 211 with a concentric concave contour (as shown in FIGS. 10F and 10G). The pusher 134 is attached to a predetermined point of the proximal inlet 210 of the funnel-shaped outer catheter.

[0102] As shown in FIGS. 2A, 2C, 7, and 8A and 8B, the outer delivery sheath 120 of the outer catheter 36 extends between a proximal end 132 located in the middle portion 42 of the target system 10 and a distal end 160 located in the distal portion 40. In the distal portion 40 of the target guide catheter extension / pre-dilation system 10, the inner member 34 is configured in a tapered configuration 104 having a distal tapered portion (also referred to herein as the distal tapered tip) 162 that may be formed with a microcatheter 46, as shown in FIGS. 2A and 2B, 5A and 5B, 6A and 6B, 8A, 22A and 22B, and 24A and 24B. The microcatheter 46 is a long and thin member having a length in the cm range, for example, 1 to 3 cm. The microcatheter 46 has a tapered conical contour shape with a diameter not exceeding 1 mm at its distal end 52. The microcatheter 46 may be integrally formed with the tapered distal tip 162 of the inner member 34.

[0103] As shown in FIGS. 2A, 5A-5C, 7, and 8A and 8B, at the distal end 160, the outer delivery sheath 120 is formed with an outer tip portion 164 having a tapered conical profile that may be interconnected with the distal tip portion 162 of the inner member 34. The outer tip portion 164 of the outer member 36 provides a smooth distal taper transition between the distal end 160 of the sheath 120 and the distal portion 40.

[0104] In FIGS. 2A, 5A and 5B, 6A and 6B, 8A and 8B, 22A and 22B, and 24A and 24B, the distal tip portion 162 of the inner catheter 34 is shown to have a tapered configuration that gradually changes from the point of interconnection with the outer tip portion 164 of the sheath 120 to the distal end 166 of the distal tip portion 162. The microcatheter 46 extends from the distal end 166 of the distal tapered portion 162 of the inner member 34 by an integral connection (a length of about 1-3 cm) and terminates at the outermost distal end 52.

[0105] The subject guide catheter extension / pre-dilation system 10 can be configured to have a difference in flexibility of the microcatheter that is more flexible at the distal portion, by either varying the durometer of the plastic (polymer) components from the proximal portion to the distal portion of the outer delivery sheath (i.e., the durometer is higher in the proximal portion compared to the distal portion), and / or varying the pitch of the helical coil of the wire in the microcatheter 46 in the direction from the proximal portion to the distal portion, such that the distal portion of the microcatheter is more flexible and compliant than the proximal portion of the microcatheter delivery device and has a significantly smaller outer profile and is more flexible than the distal portion of the guide catheter extension subsystem (outer delivery sheath).

[0106] Furthermore, the system 10 can include a wire having radiopacity such that the balloon member 44, the microcatheter 46, and the outer delivery sheath 120 can be easily visualized using fluoroscopy. It is envisioned that the distal tip 162 (as shown in FIGS. 5A, 6A, and 6B) can be provided with radiopaque markers 264, 266 near the proximal portion 112 and the distal portion 114 of the balloon 44. The radiation markers 264, 266 enable a surgeon (operator) to visualize the position of the balloon member 44 relative to the lesion location 22.

[0107] Furthermore, the outermost distal tip 52 of the microcatheter delivery portion 46 and the tip 160 of the sheath 120 can have one or more radiopaque markers 268, 270 (shown in FIGS. 2B and 5A) to enable differentiation of the radiation markers for the surgeon, which is particularly important when the microcatheter passes through an occlusive lesion and the balloon member carried in proximity to the microcatheter is held in a predetermined position.

[0108] As shown in detail in FIG. 7, in one embodiment, the outer catheter 36 is configured to include a catheter shaft coil reinforcement system 170 disposed (or embedded) on the inner surface 152 of the sheath 120. Preferably, a lubricious liner 172 is disposed inside the shaft 120. The shaft reinforcement coil 170 can be installed inside the shaft 120 in contact with the lubricious liner 172, i.e., surrounding the surface of the lubricious liner 172 that covers the inner surface 152 of the shaft 120. A distal soft tip jacket 174 is attached to the distal end of the outer catheter shaft 120 along the longitudinal axis 176 of the outer catheter 36.

[0109] The distal soft tip jacket 174 can be adhered to the shaft 120 at the end 175 (as shown in FIG. 7) or can cover a certain length of the outer surface 173 of the shaft 120.

[0110] The distal soft tip jacket 174 extends beyond the coil reinforcement 170 and the lubricious liner 172 at the distal end 160 of the shaft 120 and terminates at a tapered portion 178 having a distal edge 184 and a proximal edge 182.

[0111] The lubricious liner 172 may be formed from a PTFE material. The distal soft tip jacket 172 may be formed from a very low durometer elastomeric Pebax material that transitions to a high durometer along the longitudinal axis 176 toward the proximal end 132 of the sheath 120.

[0112] As shown in FIGS. 7 and 8A and 8B, in one of the preferred embodiments, the inner diameter of the sheath 120 at the inner surface 152 is about 0.048 inches while the outer diameter of the shaft 120 at the outer surface 173 is 0.058 inches. The inner diameter at the distal edge 184 of the tapered portion 178 of the outer catheter 36 is about 0.045 inches while the outer diameter at the distal edge 184 of the tapered portion 178 is about 0.047 inches. The gradient between the outer diameter of the sheath 120 (0.058 inches) and the outer diameter of the taper 178 (0.047 inches) defines the outer taper, while the gradient between the inner diameter of the sheath 120 (0.048 inches) and the inner diameter of the taper 178 at the distal edge 184 (0.045 inches) defines the inner taper. The distal wall 180 of the tapered portion 178 has a thickness reduction from the boundary 182 (between the sheath 120 and the tapered portion 178) to the outermost edge 184 of the tapered portion 178 of the distal soft tip jacket 174.

[0113] As shown in FIGS. 7 in combination with FIGS. 8A and 8B, the outer diameter of the tapered element 104 of the inner catheter has an outer diameter of approximately 0.046 inches, which is approximately 0.001 inches larger than the inner diameter (0.045 inches) of the distal tip of the outer catheter at its outermost distal edge 184. This difference between the outer diameter of the tapered element 104 of the inner catheter 34 and the inner diameter at the distal edge 184 of the outer tip 164 of the outer catheter results in the expansion of the distal soft tip jacket 174 in the tapered portion 178 when interfering with the tapered element 104 of the inner catheter. Such a configuration provides a substantially seamless transition between the distal tip of the inner catheter 34 and the distal tip of the outer catheter 36, as well as a small outer shape at the distal end due to the compression of the distal tip of the inner catheter 34 by the tapered element 178 of the outer catheter 36. When the inner catheter 34 is removed, the elastomeric properties of the distal tip of the distal soft tip jacket 174 of the outer catheter 36 allow the tapered portion 178 to return to its original inner diameter (0.045 inches).

[0114] In the non-engaged mode of operation, the inner diameter of the wall 180 of the tapered outer tip 164 of the outer member 36 is smaller than the outer diameter of the inner member 34. In the engaged mode of operation, the tapered outer tip 164 of the outer member 36 and the inner member 34 interact such that the dimensional transition between the outer diameter of the tapered outer tip 164 of the sheath lumen 120 and the outer diameter of the distal portion of the inner member 34 forms a boundary transition portion with substantially no step therebetween.

[0115] Referring further to FIGS. 9A - 9D, for the tapered portion 178, several embodiments of an expandable tapered design are contemplated. As shown in FIG. 9A, the elasticity in the distal tapered portion 178 of the outer catheter 36 is increased by an expandable split ring 190 attached to the tapered portion 178 that allows the distal outer tip 164 to expand (when interfacing with the inner catheter 34). The expandable split ring 190 has a slit 192 that allows the ring 190 to expand and contract in response to interference at the distal end between the inner and outer catheters. This structure provides additional reinforcement to prevent permanent deformation of the tapered portion 178 during removal of the inner catheter 34 and insertion of the stent (or balloon).

[0116] Referring to FIG. 9B, in an alternative embodiment of the outer catheter 36, the tapered portion 178 may be configured with an expandable tip scaffold 194, which may be made of NiTi wire and may be configured with a distal end 196 and a proximal end 198 having a diameter larger than the diameter of the distal end 196. Due to its flexibility, the expandable scaffold 194 expands and contracts as needed, providing additional support to resist permanent deformation of the jacket 174 in the tapered portion 178 during removal of the inner catheter and insertion of the stent or balloon member.

[0117] Another alternative embodiment of the tapered portion 178 at the distal end of the sheath 120 is shown in FIGS. 9C and 9D, where the wall 180 of the tapered portion 178 is formed with a slit 200 that extends longitudinally along the length of the tapered portion 178 that spreads apart along its perimeter. When the tapered portion 178 interfaces with the distal end of the inner member 34, the slit 200 temporarily expands to receive the distal tip 162 of the inner catheter 34. This design can prevent permanent deformation of the jacket 174 in the tapered portion 178 that may be caused by removal of the inner catheter 34 or during insertion of the stent / balloon.

[0118] An important "seamless" aspect of the system in question is that the transition between the outer diameter of the outer tip 164 of the sheath 120 (at its tapered portion 178) and the outer diameter of the distal tip 162 of the inner member 34 forms a substantially gradual (smooth) transition therebetween.

[0119] As shown in FIGS. 2C, 10A-10G, 11A-11C, 12A-12C, 13A and 13B, 14A and 14B, and 15A-15D, the system in question is constructed in an intermediate portion 42 by an interconnection mechanism 220 including a proximal coupler 130 formed at the proximal end 132 of the sheath 120 of the outer member 36, and a cooperating mechanism 222 formed on the outer surface of the inner member 34 (as shown in FIGS. 17A and 17B, 18B, 19A and 19B, and 20A-20C).

[0120] The guide catheter extension / pre-dilation system 10 in question can operate in an inner / outer catheter engagement mode and an inner / outer catheter disengagement mode, which is achieved by controlling the interconnection mechanism 220. The interconnection mechanism 220 in question is configured to engage / disengage the inner and outer catheters 34, 36 (as required in cardiac surgery) and prevent unwanted forward displacement of the inner member 34 inside the outer delivery sheath 120. The engagement operation mode enables improvement in the "pushability" of the "entire system" (having the outer catheter 36 connected to and locked to the inner catheter 34), even if the connected push / pull element 134 of the outer member 36 is configured as a flexible element of small outer shape (as flexible as or more flexible than the outer tubular sheath 120 of the outer catheter 36).

[0121] The interconnection unit 220 operates based on the interference between the proximal coupler 130 configured at the proximal end 132 of the sheath 120 and the cooperating mechanism 222 configured on the outer surface 224 of the inner member 34 when the inner surface 152 of the tubular body 150 of the sheath 120 (at the proximal end 132) engages the outer surface 224 of the cooperating mechanism 222 (on the inner member 34).

[0122] As an example, several interconnection mechanisms applicable to the target guide catheter extension / pre - dilation system 10 are envisioned. The target engagement mechanism is configured to provide controllable engagement / disengagement between the inner member 34 and the outer member 36 and to prevent forward movement of the inner member 34 relative to the outer delivery sheath 120 beyond a predetermined position.

[0123] For example, as shown in FIGS. 11A - 11C, a laser - cut coupler 130 can be formed of a proximal open (split) ring 240 and a pair of distal rings including a solid distal ring 242 and an open (split) distal ring 244. The proximal open ring 240, and the distal rings 242 and 244 are formed integrally with a coupler base 246. The coupler 130 can be formed from stainless steel or heat - set NiTi. The pusher / puller element 134 of the outer catheter 36 and the shift intermediate coupler (also referred to herein as the proximal coupler) 130 are made of a shape - memory metal (e.g., nitinol, etc.) to prevent deformation during forward or reverse movement of the outer member and to prevent deformation of the shaft intermediate coupler 130 when a stent (or other device) passes through the shaft intermediate portion of the outer catheter 36.

[0124] The proximal opening ring 240 is correlated with the proximal inlet opening 211 (e.g., funnel-shaped) of the outer catheter 36 (shown in FIGS. 10A, 10D, 10E, and 11C). The proximal opening ring 240 enables the expansion of the inlet 211 into the funnel 210 as required for the insertion / removal of the inner catheter 34 as required in the surgery. As shown in FIGS. 10A, 10D, 10E, and 11A - 11C, the proximal opening ring 240 provides support for the proximal opening 210 of the funnel-shaped proximal end of the sheet 120. The proximal ring 240 reinforces the inlet opening ("mouth") 211, prevents damage or permanent deformation of the inlet opening, and supports the elastic properties of the sheath 120 at the inlet opening 210. The distal rings 242, 244 form a snap-fit locking mechanism separate from the proximal opening ring 240 of the funnel. The distal ring 242 does not expand (it has a closed circular contour), but the opening of the split ring 244 widens upon displacement of the inner catheter 34 relative to the proximal coupler 130 of the outer catheter 36.

[0125] The base 246 of the coupler 130 may be flat or preferably slightly arcuate (in cross-section) so as to match the cooperating distal end 250 of the pusher 134 having a contour of either flat or crescent (in the transverse direction) as shown in FIGS. 11B and 11C. The pusher 134 can be manufactured from stainless steel or NiTi. The distal end 250 of the pusher 134 is welded (attached by adhesion, attachment, or other means) to the base member 246 of the coupler 130. A PTFE liner 172 (also shown in FIG. 7) can surround the coupler 130 as shown in FIG. 11C.

[0126] The sheath 120 is disposed in a surrounding relationship around the coupler and the PTFE liner 172. A Pebax-based encapsulation similar to the distal soft tip jacket 174 of the distal end 160 of the sheath 120 (shown in FIG. 7) can be used at the proximal end 132 of the sheath 120. The length of the catheter shaft coil reinforcement 170 (also shown in FIG. 7) at the distal end of the outer catheter 36 can be extended to the proximal end of the outer catheter 36.

[0127] As shown in FIGS. 11A-11C, FIGS. 17A-17C, and FIGS. 18A and 18B, the cooperation mechanism 222 for the specific embodiment shown in FIGS. 11A-11C further includes a shaft intermediate locking ring 252 (shown in FIGS. 17B, 17C, and 18B) for a snap-fit lock.

[0128] Another embodiment of the proximal inlet structure of the outer catheter shown in FIGS. 12A-12C is similar to that shown in FIGS. 11A-11C, but with certain modifications including the following. (a) Additional thickness and additional material around the base 246 of the coupler 130, (b) A modified surface treatment (e.g., bead blasting) to improve the adhesion of the polymer encapsulation, and (c) The use of encapsulation with a rigid polymer (such as nylon) to provide additional support to the funnel to prevent damage that may interfere with the passage of the stent.

[0129] An additional embodiment of the coupler 130 at the proximal inlet 210 (shown in FIGS. 13A and 13B) features an open ring (rib) 256 that reinforces the inlet port 210. The snap-fit lock 260 is represented by at least two open rings 262 at the distal end of the coupler 130. The coupler 130 is preferably a laser-cut coupler formed from either stainless steel or heat-set NiTi, as shown in the variants shown in FIGS. 13A and 13B.

[0130] The hypo tube pusher / puller 134 may be flattened at its distal end 250 and welded to the base 246 of the coupler 130. The PTFE liner 172 extends below the coupler 130, and the Pebax encapsulation 174 wraps the coupler 130 to which the pusher 134 is attached. The catheter shaft coil reinforcement structure 170 extends along the shaft 120 of the outer catheter 36 from its distal end to its proximal end. The snap fit lock 260 cooperates with the circular ring embodiment of the cooperating mechanism 222 shown in FIGS. 17A-17C and 18B. In some embodiments, the encapsulation 174 and / or the pusher / puller 134 may be color-coded in a prominent color, as shown in FIG. 11A, to distinguish the pusher / puller 134 of the outer member from the other elements of the configuration for the convenience of the surgeon and the safety of the surgery.

[0131] Further variations of the coupler 130 are shown in FIGS. 14A and 14B, where the coupler 130 has individual rings 266, 268 welded to the distal end 250 of the pusher 134. As shown, the locking mechanism 260 is formed by a solid distal ring 266 and an intermediate split ring 268, and each ring 266, 268 is welded to the pusher 134. The proximal inclined split ring 270 is also welded to the pusher 134. This design provides improved flexibility regarding the size and configuration of each of the rings 266, 268, and 270, and supports the formation of various funnel shapes / dimensions, as opposed to a laser cut coupler limited to a single diameter.

[0132] Figures 15A and 15B show another variant of the proximal coupler 130 featuring a funnel window that improves the contrast agent injection flow rate by providing an additional open cross-sectional path for the fluid flow. As shown in Figures 15A and 15B, a circular opening 272 is formed in the sheath 120. The opening 272 is arranged in a predetermined pattern in such a manner that it is not obstructed by the proximal split ring 274 and the distal rings 276, 278 of the snap-fit lock structure 280. As shown in Figures 15C and 15D, the coupler 130 is formed with a triangular opening 282 formed in the sheath 120 in such a manner that it is not obstructed by the proximal ring 274 and the distal rings 278, 276 of the snap-fit lock 280.

[0133] Only the circular and triangular openings 272, 282 are shown in Figures 15A - 15D, but other configurations of the plastic encapsulation notch are also conceivable in the structure of interest such that the injected contrast fluid can pass through the notch.

[0134] Referring to Figures 16A, 16B, and 16C, another embodiment of the proximal end of the outer catheter 36 is shown, which is particularly designed as a potential solution to prevent an undesirable plugging situation when air accidentally enters the fluid injected between the inner and outer catheters 34, 36. To prevent this, a flush lumen 290 is incorporated into the pusher 134 via a flat hypo tube. A luer hub is connected to the proximal end of the hypo tube (pusher 134) as shown in Figure 16C, and thus, the surgeon can inject fluid between the inner and outer catheters via the hypo tube 134. When the fluid enters the outer catheter lumen 292 through the channel 290 in the hypo tube 134, the entry of air bubbles between the inner and outer catheters is prevented.

[0135] Further, referring to FIGS. 17A-17C, the interconnect unit 220 between the proximal couplers 130 shown in FIGS. 11A-11E, FIGS. 12A-12C, FIGS. 13A and 13B, FIGS. 14A and 14B, and FIGS. 15A-15D includes a cooperating member 222 in the form of an annular circular ring 252 (also referred to herein as an intermediate lock ring) formed on the outer surface 224 of the inner catheter 34. The stainless steel annular ring 252 is contoured with a perfectly round surface that allows for minimal reversible engagement / disengagement from the required split ring mechanism of the outer catheter coupler 130. The ring 252 shown in FIG. 17C has a rounded contour on the outer surface 302 for a smooth lock / lock release operation. The inner surface 304 of the ring 252 is also a smooth structure that engages the outer surface 224 of the inner catheter 34.

[0136] FIG. 17A shows the separated configuration of the inner catheter 34 with respect to the outer catheter 36. FIG. 17B represents the locked engagement configuration when the inner catheter 34 is received and locked inside the opening 210 at the proximal end of the sheath 120 such that the ring 252 engages a snap-fit lock 306 formed by the distal solid ring 308 and the intermediate split ring 310. In this position, the proximal inclined split ring 312 surrounds the inner catheter 34 and the ring 252 is locked within the snap-fit lock 306, thus engaging the inner and outer catheters for surgical manipulation as required in a surgical procedure.

[0137] When the inner catheter 34 moves longitudinally inside the outer catheter 36, as the ring 252 passes through the proximal inclined split ring 312 and the intermediate split ring 310, the arms of these rings spread from their original positions to create sufficient space for the passage of the ring 252. When in a predetermined position, i.e., when the ring 252 is received between the rings 308 and 310, the arms of the inclined split ring 312 and the split ring 310 return to their original closed positions. The ring 252 is captured between the rings 308 and 310 and locked therebetween by snap fit, thus preventing relative displacement between the inner and outer catheters.

[0138] Referring to FIGS. 18A and 18B, which show in detail the structure shown in FIGS. 17A - 17C, a portion (pocket) 316 of the sheath 120 of the outer catheter 36, which is not reinforced by the coil 170, is shown to flex when the shaft intermediate lock ring 252 is inserted between the solid distal ring 308 of the snap fit lock 306 and the intermediate split ring 310. The flexed portion 316 of the sheath 120 between the rings 308 and 310 provides additional holding force to maintain the inner catheter 34 and the outer catheter 36 in a locked engagement state.

[0139] The stainless - steel annular ring 252 can be attached to the outer surface 224 of the inner catheter shaft 34 by an adhesive. The shape of the lock ring (a complete circular surface) allows for smooth reversible engagement / disengagement with the laser - cut features of the coupler 130 of the outer catheter. The distal ring 308 of the snap fit lock 306 prevents further distal movement of the inner catheter 34, while the intermediate split ring 310 opens when it contacts the shaft intermediate lock ring 252, providing a tactile snap. The proximal inclined split ring 312 allows the funnel 211 to open to an inner diameter larger than the inner diameter of the remaining portion of the shaft 120. It also allows for the smooth passage of the shaft intermediate lock ring 252.

[0140] Interference between the non-reinforced shaft pocket 316 and the shaft intermediate locking ring 252 results in the retention of the inner catheter 34 to the outer catheter 36 until the user attempts to remove the inner catheter 34 from the outer catheter 36 and thus break the snap-fit lock between the two. The force required to disengage the locking mechanism can be adjusted to 0.1 - 2.0 pounds.

[0141] Referring to FIGS. 19A - 19C, another alternative embodiment of a shaft intermediate lock is shown that includes a square annular ring 320 (formed of a metal or polymeric material). Different from the ring 252 shown in FIGS. 17A - 17C and FIG. 18B, the ring 320 has a square cross-section 321 as shown in FIG. 19C. The square annular ring 320 is attached to the outer surface 224 of the inner catheter 34 using a heat-sealed Pebax encapsulation 322. Alternatively, it may be adhered to the outer surface 224 of the inner catheter. As shown in FIG. 19B, when the inner catheter is in the locked position, the square annular ring 320 fits into a snap-fit lock 324 formed by a solid ring 326 and a split ring 328, the encapsulation 322 contacts the inner surface 152 of the sheath 120, and the ring 320 is positioned between the rings 326 and 328.

[0142] In a further alternative embodiment shown in FIGS. 20A - 20C, the shaft intermediate locking mechanism 220 is formed with a cooperating member 222 in the form of a cage-like structure 330 having two NiTi rings 332, 334 connected to each other via several (e.g., four) NiTi shape-setting wires 336. As shown in FIG. 20A, the cage 330 is attached to the outer surface 224 of the inner catheter 34 by either adhesion or a heat-sealed Pebax encapsulation 338. Each of the wires 336 has an arcuate extension portion 340 left free from the encapsulation 338 as shown in FIGS. 20A and 20B.

[0143] As shown in FIG. 20B, in the locked configuration, the cage structure 330 fits into the coupler 130 of the outer catheter. The unencapsulated arcuate portion 340 of each wire 336 extends away from the wire 336 of the cage 330 outside the encapsulation 338. When the cage 330 is received between the ring 342 and the split ring 344 of the snap - fit mechanism 346, the locking mechanism 346 is actuated and the inner and outer catheters 34, 36 are engaged.

[0144] Referring further to FIG. 21, the proximal coupler 130 of the outer catheter 36 can include two lock slots 350, 352 formed by rings 354 and 356 connected by a connecting element 358.

[0145] Referring to FIGS. 17A - 17C, FIGS. 18A and 18B, FIGS. 19A and 19B, FIGS. 20A - 20C, and FIGS. 10A - 10G, FIGS. 11A - 11C, FIGS. 12A and 12B, FIGS. 13A and 13B, FIGS. 14A and 14B, FIGS. 15A - 15D, and FIG. 21, when the surgeon linearly displaces the inner member 34 within the inner channel 122 of the proximal coupler 130, the snap - fit annular rings 252, 320, or the cage 330 enters the channel 122 between the arms of the proximal rings 240, 312 that are flexibly bent outward to allow forward movement of the inner catheter 34 (towards the distal tip 162). As the snap - fit annular rings 252, 320, or the cage 330 further pass through the intermediate split rings 244, 262, 268, 310, 328 of the snap - fit lock, the arms of the inclined proximal rings return to their original positions, but the arms of the intermediate split rings are flexibly bent outward to allow the rings 252, 320 of the cage 330 to be positioned between the distal solid ring and the intermediate split ring. When the ring / cage 252, 320, 330 snap - fits between the rings of the snap - fit locking mechanism, the arms of the intermediate split ring return to their original positions.

[0146] To separate the inner member 34 from the outer member 36, the surgeon pulls the inner member 34 from within the inner channel of the proximal coupler 130. When removing the snap-fit annular rings / cages 252, 320, 330 from the channel, the pulling action bends the arms of the intermediate split ring outward so that the snap-fit annular rings / cages 252, 320, 330 can pass therebetween, and thus the inner catheter 34 is released from the proximal coupler 130 of the outer catheter 36.

[0147] Returning to FIG. 3D, the expandable lumen distal shaft 66 of the intermediate portion 42 of the subject guide catheter / pre-dilation extension system 10 can be manufactured with a braided reinforcement structure 260. The braided reinforcement member 260 forms a somewhat flexible tube connected to the cooperating mechanism 222 of the interconnecting unit 220 of the inner member 34. An RX (rapid exchange) port 94 for passing the guide wire 12 therethrough can be formed through the wall of the braided and reinforced expandable lumen distal shaft 66.

[0148] The braided reinforcement structure 260 can be composed of a metal pattern or wire within the braided and reinforced expandable lumen distal shaft 66 to prevent kinks that are thought to impart longitudinal stiffness to the shaft 66. The metal braid 260 can be embedded in the braided and reinforced shaft 66 to add the high flexibility required for the retraction of the inner member 34 relative to the outer delivery sheath 120 during surgery.

[0149] A flat wire helical coil having a wire thickness of about 1 mil to 3 mils (e.g., made from a shape memory alloy such as nitinol) can be embedded in the braid 260. This coil can be formed with a very thin plastic coating disposed on its inner and outer surfaces, which facilitates reducing the wall thickness of the expandable lumen distal shaft 66 to less than 7 mils, preferably about 5 mils.

[0150] The principle of reinforcing a tubular member with a catheter shaft coil reinforcement 170 in the form of a flat spiral coil 262, or forming a tubular member from a flat spiral coil, can be applied to the outer delivery sheath 120 (as shown in FIGS. 7, 8B, 9A-9D, 10A, 11C, 12B and 12C, 13A and 13B, 14B, 15A-15C, 16A and 16B, 17A and 17B, 18A and 18B, 19B, 20B, and 21) and the microcatheter 46 (as shown in FIGS. 2A and 2B, 5A, 22, and 24A-24B) in the targeted guide catheter extension / pre-dilation system 10. In the outer delivery sheath 120 and / or the microcatheter 46, such flat spiral coils can be embedded at predetermined positions along the length of their walls, such as the proximal end and / or the distal end.

[0151] Alternatively, the entire length of the outer delivery sheath 120 and / or the microcatheter 46 can be formed with flat spiral coils. The pitch between the coils can be adjusted to provide a flexibility gradient along the length of the tubular member (sheath 120 and / or microcatheter 46) that increases towards the distal end to facilitate non-invasive surgery.

[0152] Referring to FIGS. 22A and 22B and FIGS. 23A-23C, instead of utilizing a standard over-the-wire (OTW) guide wire lumen, a monorail rapid exchange (RX) design of the inner catheter 34' can be implemented to enable the use of a short guide wire. In the embodiment shown in FIGS. 22A and 22B, which represent an isometric view of the target coil-reinforced inner member shaft 400 and a side view obtained along its line A-A, the distal portion 40' of the inner member 34' includes a tapered element 402 attached to the outer surface 224 of the inner member 34. The outer shaft 400 of the inner member 34' is a coil reinforced with a coil reinforcement structure 404 extending from the distal tip 406 to the RX inlet port 94 shown in FIGS. 2A-2C and FIGS. 3C and 3D. The distal tip 406 is a tapered soft tip that interfaces with the inner surface of the outer catheter 36 together with the tapered element 402 when the inner catheter 34' is loaded into the outer catheter 36 as required in surgery.

[0153] The distal portion 40' includes a concentric guide wire lumen 408 that communicates with the RX inlet port at the proximal end of the inner catheter 34 (shown in FIGS. 2A-2C and FIGS. 3C and 3D).

[0154] As shown in FIGS. 23A-23C, the proximal end 412 of the monorail microcatheter embodiment shown in FIGS. 22A and 22B utilizes a machined hypo tube pusher 414. The proximal end 412 of the coil-reinforced inner member shaft 416 and the hypo tube pusher 414 are enclosed within a proximal outer jacket 418 that extends along (and includes) the coil-reinforced inner member shaft 416 (functioning as the guide wire lumen 408) and the hypo tube pusher 414 shown in FIGS. 22A and 22B as a tube along the proximal end 412 of the monorail microcatheter embodiment of the inner member 34'.

[0155] The embodiment shown in FIGS. 23A and 23B features an RX guide wire “notch” termination / entry 420 that is manufactured by puncturing the proximal outer jacket 418. Subsequently, the coil-reinforced inner member shaft 416 is inserted into the proximal outer jacket tube 418 through the RX entry “notch” 420. The tapered hypo tube 415 is further inserted into the proximal outer jacket tube 418 through its lumen 422, and the polymers of the coil-reinforced inner member shaft 416 and the proximal outer jacket tube 418 are fused together to connect the inner member shaft 416 and the pusher 414, thus forming the proximal end 412 of the monorail microcatheter inner member 34'.

[0156] For the convenience of the surgeon, the push / pull element 134 of the outer catheter 36 can be colored (color-coded) as shown in FIG. 11A to distinguish it from other elements of the system such as the push / pull element of the inner catheter 34, as well as the normal gray or silver color of the coronary guide wire or stent delivery system used for the delivery of the device. Alternatively, the proximal outer jacket 418 of the push / pull element 414 may be color-coded such that its color is distinguishable from the colors of the other elements within the system of interest.

[0157] Referring further to FIGS. 24A and 24B, which depict an embodiment 500 of an additional coil-reinforced balloon catheter for the inner catheter, this configuration combines the reinforcing shaft characteristics of the microcatheter 46 with those of an expandable balloon 44 having the following attributes. a. The coil-reinforced shaft 502 provides additional kink resistance and pushability while still maintaining flexibility to navigate tortuous vasculature. b. The longer distal tip 504 of the structure includes a small-profile tapered soft tip for easily crossing stenoses and narrow lesions.

[0158] As shown in FIGS. 24A and 24B, the distal portion 504 of the target structure 500 includes an inner member shaft 500 reinforced by a coil reinforcement structure 506 extending along the length of the shaft 500 of the inner member. A distal taper element 508 is disposed on the inner member shaft 500 and extends between ends 510 and 512 in a relationship surrounding the inner member shaft 500. The distal tapered soft tip 514 may be in the form of a microcatheter 46 disposed at the end of the coil reinforcement shaft 500.

[0159] Similar to the embodiments shown in FIGS. 22A and 22B, the balloon member 44 is disposed on the inner member shaft 500, and the radiopaque markers 264 and 266 are disposed on the inner member shaft 500 within the balloon member 44. At its proximal end 516, the balloon member 44 interferes with the outer tip 164 of the proximal taper element 178 of the outer member sheath 120. At the distal end 518, the balloon member 44 closely surrounds the shaft 500.

[0160] Returning to FIGS. 1 - 24B, in the operation for performing a heart surgery, particularly a pre - dilation routine, the proximal end of the coronary guide wire 12 is passed into the RX port 94 formed in the dilation lumen distal shaft 66 and directed through the inner channel (GW lumen 96) of the inner member 34 to the outermost distal end 52 of the microcatheter 46 and extended beyond the outermost distal end 52 of the microcatheter 46. Thereafter, the guide catheter 14 is advanced into the target blood vessel 16.

[0161] Subsequently, the outer delivery sheath 120 of the outer member 36 with the inner member 34 locked inside is first placed inside the internal channel 48 of the guide catheter 14 together with the microcatheter 46, and both the inner and outer members 34, 36 as a single unit are advanced integrally through the guide catheter 14 towards the treatment site 22. The sheath 120 of the outer member and the inner member 34 can be displaced integrally by pushing the outer member pusher 134. By this operation, the microcatheter 46 of the inner member 34 slides along the GW12 together with the outer member 36 until it extends past the distal end 50 of the guide catheter 14 and reaches the lesion site 92. At this stage of the procedure, the balloon member 44 is in a contracted configuration.

[0162] The guide wire 12 extending past the distal end 50 of the guide catheter 14 functions as a guide for sliding the microcatheter 46 (with the balloon 44 in a contracted state attached to the distal tip 162) towards the treatment site 26.

[0163] Subsequently, the balloon member 44 (located at the treatment site 22) is inflated by a balloon inflation system 62 connected to the inflation hub 56 via an inflation lumen formed by the inflation lumen distal shaft 66 and the inflation lumen hypo tube 64 in order to compress the plaque and widen the blood passage in the blood vessel 16.

[0164] Subsequently, once the lesion is expanded, the balloon 44 is deflated and the outer delivery sheath 120 can be advanced across the lesion 22 as a unit integral with the inner member 34 (in the engagement operation mode), and then the inner member can be detached (unlocked) from the outer delivery sheath 120 and removed from the sheath 120.

[0165] Alternatively, the inner member 34 can be detached from the sheath 120 and withdrawn immediately after the lesion is expanded, while the outer member 36 can be advanced across the lesion 22.

[0166] The sheath 120 may be left at a predetermined position proximal to the treatment site (immediately after the expansion of the lesion).

[0167] After pulling the inner member 34, the stent can be delivered to site 22. The stent can be introduced inside the sheath 120 into the blood vessel 16 in its closed configuration. When at a predetermined position, a stent support balloon (not shown) can be inflated to open the stent. Thereafter, the outer delivery sheath 120 is removed and the opened stent is left in the blood vessel 16.

[0168] Although the present invention has been described in connection with its specific forms and embodiments, it will be understood that various modifications other than those described above can be relied upon without departing from the spirit or scope of the invention as defined in the appended claims. For example, specifically illustrated and described elements can be replaced with functionally equivalent elements, specific features can be used independently of other features, and in certain cases, the specific positions of elements, steps, or processes can be reversed or intervened, and none of these depart from the spirit or scope of the invention as defined in the appended claims. [Appendix 1] An intravascular delivery system having a proximal portion, a distal portion, and an intermediate portion located between the proximal portion and the intermediate portion, and configured to be controllably displaced within a target blood vessel, Formed by a flexible, substantially cylindrically contoured elongated outer delivery sheath defining a sheath lumen having a proximal end and a distal end, the outer delivery sheath extending between the intermediate portion and the distal portion, and the outer member configured with a tapered outer tip at the distal end of the sheath lumen, The tapered outer tip of the outer member at the distal end of the outer delivery sheath is configured with a wall extending in a cylindrical aspect between a distal edge and a proximal edge of the tapered outer tip, the wall having an inner diameter and an outer diameter, and the inner diameter and the outer diameter of the wall gradually decreasing in a direction from the proximal edge to the distal edge of the tapered outer tip, the outer member, It has an elongated body defining an internal channel extending along the longitudinal axis, and is an inner member extending along the inside of the sheath lumen of the outer member in a controllable relationship with the outer delivery sheath, The elongated body of the inner member has an outer diameter and has a tapered distal portion configured with a tapered delivery catheter having an elongated body of a predetermined length. The tapered delivery catheter is displaceable beyond the distal end of the sheath. The wall of the tapered outer tip of the outer member interfaces, at least temporarily, with the distal portion of the inner member. At the interface between the wall of the tapered outer tip of the outer member and the distal portion of the inner member, the inner diameter of the wall of the tapered outer tip of the outer member is smaller than the outer diameter of the distal portion of the inner member. An inner member, An interconnect mechanism operably coupled to the inner and outer members and controllably actuated to operate the guide catheter extension / pre-dilation subsystem in an engagement mode of operation or a separation mode of operation, Comprising, In the engagement mode of operation, the inner and outer members of the guide catheter extension subsystem engage to be controllably displaced together along the guide wire. The inner member cannot be displaced independently relative to the outer member during engagement. In the separation mode of operation, the inner and outer members are disengaged to retract the inner member from the outer member. An intravascular delivery system. [Appendix 2] The tapered distal portion of the inner member interfaces, on its outer surface, with the inner surface of the tapered outer tip of the sheath lumen. The tapered outer tip of the outer member is an elastomeric tapered outer tip. In the separation mode of operation, the inner diameter of the wall of the tapered outer tip of the outer member is smaller than the outer diameter of the inner member. In the engagement operation mode, the outer tapered distal end portion of the sheath lumen and the distal portion of the inner member interact such that the transition of the dimension between the outer diameter of the outer tapered distal end portion and the outer diameter of the distal portion of the inner member forms an interface substantially free of a step therebetween. The intravascular system according to appended claim 1. [Appended claim 3] The sheath is reinforced along its length, and the outer member further includes a distal soft tip encapsulation material at its distal end that encapsulates the reinforced sheath of the outer member. The distal soft tip encapsulation material is a flexible low durometer elastomeric material having a durometer value with a gradient that increases from the distal end to the proximal end of the sheath. The system according to appended claim 1. [Appended claim 4] The outer member further includes a distal lubricating liner sandwiched between the outer surface of the sheath and the inner surface of the distal soft tip encapsulation material. The system according to appended claim 3. [Appended claim 5] The delivery catheter is a microcatheter. A balloon member attached to the tapered distal portion of the inner member in proximity to the tapered delivery microcatheter. An inflation lumen extending between the proximal portion and the distal portion of the balloon member inside the inner member and providing a fluid passage between an external balloon inflation system and the balloon member. The system according to appended claim 1, further comprising. [Appended claim 6] The balloon member has a proximal portion having a proximal diameter that exceeds the distal outer diameter at its distal portion. The intravascular system according to appended claim 5. [Appended claim 7] The balloon member is in an inflated state and a deflated state. In the deflated state, the balloon member is displaced within the blood vessel. The balloon member is controllably changed to the inflated state after being disposed at least aligned with the treatment site for a pre-dilation procedure. The intravascular system according to appended claim 5. [Appended claim 8] The elongated body of the inner member and the microcatheter are reinforced with a coil along their lengths, and the tapered distal portion of the inner member comprises a distal taper element disposed on the coil-reinforced elongated body, the system according to appended claim 5. [Appended Note 9] The outer delivery sheath of the outer member has a tubular body having a first predetermined outer circumference, and the tubular body of the outer member extends between the tapered outer tip at the distal end of the outer delivery sheath and the proximal end, at which proximal end the outer delivery sheath is configured to include an inlet opening having a second predetermined outer circumference, the second predetermined outer circumference of the inlet opening exceeding the first outer circumference of the tubular body of the outer delivery sheath, the system according to appended claim 2. [Appended Note 10] The tapered outer tip of the outer member has a configuration that can elastically expand, and the inlet opening at the proximal end of the outer sheath is contoured in a funnel shape, the system according to appended note 9. [Appended Note 11] An outer member pusher configured to include a flattened portion at the distal end and fixed to the proximal end of the sheath of the outer member further comprising The outer member pusher is configured to include a channel extending along its length, the channel communicating with the sheath lumen, the intravascular system according to appended claim 2. [Appended Note 12] The outer sheath of the outer member is a flexible sheath having a first flexibility along its length, and the outer member pusher is a flexible member having a second flexibility along its length, the second flexibility being substantially the same as or exceeding the first flexibility, the intravascular system according to appended note 11. [Appended Note 13] The interconnecting mechanism includes a snap - fitting mechanism. The snap - fitting mechanism is configured to include a proximal coupler disposed at the proximal end of the sheath of the outer member and a cooperating element disposed on the outer surface of the elongated body of the inner member. The proximal coupler includes a distal solid ring and an intermediate split ring disposed at a predetermined distance from the solid ring. The cooperating member includes a member selected from the group including a shaft intermediate lock ring, a square annular ring, and a snap - fitting cage. The cooperating member is attached to the outer surface of the elongated body of the inner member and is releasably locked in a snap - fitting manner between the distal solid ring and the intermediate split ring to engage the outer and inner members. The intravascular system according to Appendix 1. [Appendix 14] The cooperating member is fixed to the outer surface of the inner member in a surrounding relationship therewith. The proximal coupler further includes a proximal inclined split ring at its proximal end. The intravascular system according to Appendix 13. [Appendix 15] The system according to Appendix 14, further including a window system formed at the proximal end of the sheath. [Appendix 16] The micro - catheter is formed of a flexible material having varying flexibility along its length, and the flexibility of the micro - catheter increases towards its distal end. The intravascular system according to Appendix 5. [Appendix 17] The micro - catheter includes a flat - angled helical coil extending along the predetermined length of the micro - catheter, and the pitch of the flat - angled helical coil varies along the length of the micro - catheter such that the flexibility of the micro - catheter increases towards its distal end. The intravascular system according to Appendix 16. [Appendix 18] The intravascular system according to appended note 1, further comprising a flat helical coil member forming at least a part of the wall of each member selected from the group consisting of the outer feed sheath of the outer member, the feed catheter, the elongated body of the inner member, and combinations thereof, wherein the flat helical coil is formed of a shape memory alloy such as nitinol or is formed of a radiopaque material. [Appended note 19] The tapered feed catheter structure is a microcatheter formed with a longitudinally extending lumen for sliding along a guide wire. An inner member pusher coupled to the proximal end of the inner member at its distal end, And an outer member pusher coupled to the proximal end of the outer member at its distal end Further comprising, The outer member pusher is color - coated, and the color coating has a color distinguishable from the color of the guide wire and the colors of the inner member and the inner member pusher. The intravascular system according to appended note 1. [Appended note 20] An intravascular system comprising a guide catheter extension subsystem cooperating with a guide wire, A guide catheter extension subsystem having a proximal portion, a distal portion, and an intermediate connecting portion interconnected between the proximal and distal portions Comprising, The guide catheter extension subsystem, An outer member formed by a flexible, substantially cylindrically contoured elongated sheath, the sheath having a reinforcing structure along the sheath, the sheath defining a sheath lumen having a proximal end and a distal end, the sheath extending between the intermediate connecting portion and the distal portion of the guide catheter extension subsystem, the outer member having a distal soft elastic tip disposed at the distal end of the sheath lumen, the distal soft elastic tip being configured with a cylindrical wall having a thickness decreasing from a proximal edge to a distal edge of the distal soft elastic tip, the wall having an inner diameter at the distal edge. The outer member, An inner member having an elongated body reinforced by a coil defining an internal channel extending along a longitudinal axis, the inner member extending inwardly along the sheath lumen in a controllably displaceable relationship with the sheath, the inner member having a tapered distal portion of the distal end configured with a tapered delivery catheter structure, the tapered distal portion of the inner member having an elongated body reinforced by a coil of a predetermined length, the elongated body of the inner member having an outer diameter that exceeds the inner diameter of the wall of the distal soft elastic tip of the outer member, the tapered distal portion of the inner member elastically interfacing with the inner surface of the distal soft elastic tip of the sheath on its outer surface, the tapered delivery catheter structure being displaceable beyond the distal end of the sheath, the inner member and An interconnect mechanism operably coupled to the inner and outer members of the guide catheter extension subsystem and controllably actuated to operate the guide catheter extension subsystem in an intermittent engagement mode or a separation mode of operation, in the engagement mode of operation, the outer surface of the tapered distal tip of the inner member and the outer surface of the wall of the distal soft elastic tip of the outer member forming a substantially smooth transition therebetween, the interconnect mechanism and Comprising In the engagement mode of operation, the inner and outer members of the guide catheter extension subsystem engage to be controllably displaced together along the guide wire In the separation mode of operation, the inner and outer members are separated for controllable individual linear or rotational displacement relative to each other, an intravascular system. [Appendix 21] The sheath is configured at its proximal end with an inlet opening having an outer perimeter that exceeds the outer perimeter of the tubular body of the sheath, the inlet opening being reinforced by an inclined split ring element attached in proximity to the inlet opening, the system according to Appendix 20. [Appendix 22] Further comprising a guide wire capable of advancing at least to a treatment site within a target blood vessel The guide catheter extension subsystem is configured to be controllably displaced along the guide wire, an inner member pusher coupled at its distal end to the proximal end of the inner member, an outer member pusher coupled at its distal end to the proximal end of the outer member, an elastic jacket that wraps the inner member at least at its proximal end and wraps the inner member pusher at least along its distal end and includes, The intravascular system according to appendix 20, wherein the tapered delivery catheter structure is a microcatheter formed with a longitudinally extending lumen for sliding along the guide wire. [Appendix 23] The intravascular system according to appendix 22, wherein the outer member pusher is color-coated, and the color coating has a color distinguishable from the color of the guide wire and the color of the elastic jacket that wraps the inner member and the inner member pusher.

Claims

1. 1. An intravascular delivery system configured for controllably displacing a blood vessel of a subject, the delivery system having a proximal portion, a distal portion, and an intermediate portion located between the proximal portion and the distal portion, the delivery system comprising: an outer member formed by a flexible, substantially cylindrically contoured, elongated outer delivery sheath defining a sheath lumen having a proximal end and a distal end, the outer delivery sheath extending between the intermediate portion and the distal portion and configured with a tapered outer tip, the proximal end of the outer member outer delivery sheath configured to have a mouth, the mouth configured with a funnel shape having an off-center opening; an outer member, the tapered outer tip of the outer member at the distal end of the outer delivery sheath comprising a wall extending in a cylindrical manner between distal and proximal edges of the tapered outer tip, the wall having an inner diameter and an outer diameter, the inner diameter and the outer diameter of the wall gradually decreasing in a direction from the proximal edge to the distal edge of the tapered outer tip; an inner member having an elongate body defining an interior channel extending along a longitudinal axis and extending along an interior of the sheath lumen of the outer member in controllable relationship with the outer delivery sheath, an inner member, the elongate body of the inner member having a proximal end and a tapered distal portion configured with a tapered delivery catheter having an outer diameter and an elongate body length, the tapered delivery catheter being displaceable past the distal end of the outer delivery sheath, the wall of the tapered outer tip of the outer member at least temporarily interfaces with the distal portion of the inner member, and the inner diameter of the wall of the tapered outer tip of the outer member at the interface between the wall of the tapered outer tip of the outer member and the distal portion of the inner member is less than the outer diameter of the distal portion of the inner member; an interconnection mechanism controllably actuable to operate the inner and outer members in an engaged or separated mode of operation, the interconnection mechanism including a proximal coupler formed at the proximal end of the outer delivery sheath of the outer member and a cooperating mechanism formed on an outer surface of the inner member, the proximal coupler including a proximal split ring and a pair of distal rings including a solid distal ring and a split distal ring, the proximal split ring correlating with a mouse funnel shape, the solid distal ring and the split distal ring forming a snap-fit ​​locking mechanism separate from the proximal split ring; It is equipped with in the engaged mode of operation, the inner and outer members are engaged for controllably displacing together along a guidewire, the inner member being unable to independently displace relative to the outer member when engaged; An intravascular delivery system, wherein in the separated mode of operation, the inner and outer members are separated to retract the inner member from the outer member.

2. the tapered distal portion of the inner member interfaces at its outer surface with an inner surface of the tapered outer tip; the tapered outer tip of the outer member comprises an elastomeric material; in the separated mode of operation, the inner diameter of the wall of the tapered outer tip of the outer member is smaller than the outer diameter of the inner member; 2. The intravascular delivery system of claim 1, wherein in the engaged mode of operation, the tapered outer tip of the outer member and the inner member interact such that a dimensional transition between the inner diameter of the wall of the tapered outer tip and the outer diameter of the inner member forms a substantially step-free interface therebetween.

3. 2. The intravascular delivery system of claim 1, wherein the outer delivery sheath is reinforced along its length, and the outer member further comprises a distal soft tip encapsulating material at its distal end that encapsulates the outer delivery sheath of the outer member, the distal soft tip encapsulating material being a flexible, low durometer elastomeric material having an increasing gradient of durometer from the distal end to the proximal end of the outer delivery sheath.

4. The intravascular delivery system of claim 3 , wherein the outer member further comprises a distal lubricous liner sandwiched between an exterior surface of the outer delivery sheath and an interior surface of the distal soft tip encapsulation material.

5. the tapered delivery catheter is a microcatheter; a balloon member attached to the tapered distal portion of the inner member proximate to the tapered delivery microcatheter; an inflation lumen extending within the inner member between the balloon members of the proximal and distal portions and providing a fluid passage between an external balloon inflation system and the balloon members; The intravascular delivery system of claim 1 , further comprising:

6. The intravascular delivery system of claim 5 , wherein the balloon member has a proximal portion having a proximal diameter that is greater than a distal outer diameter at a distal portion thereof.

7. 6. The intravascular delivery system of claim 5, wherein the balloon member has an inflated state and a deflated state, in which the balloon member is displaced within the blood vessel, and the balloon member is controllably changed to the inflated state after being positioned at least in alignment with a treatment site for a pre-dilatation procedure.

8. The intravascular delivery system of claim 5 , wherein the elongate body of the inner member and the microcatheter are reinforced with coils along their lengths.

9. 3. The intravascular delivery system of claim 2, wherein the outer delivery sheath of the outer member has a tubular body having a first predetermined circumference, the tubular body of the outer member extending between the tapered outer tip at the distal end and the proximal end of the outer delivery sheath, at the proximal end where the outer delivery sheath is configured with an entrance opening having a second predetermined circumference, the second predetermined circumference of the entrance opening exceeding the first predetermined circumference of the tubular body of the outer delivery sheath.

10. The intravascular delivery system of claim 9 , wherein the tapered outer tip of the outer member has a resiliently expandable configuration.

11. an outer member pusher configured with a flattened portion at a distal end and secured to the proximal end of the outer delivery sheath of the outer member; Further equipped with The intravascular delivery system of claim 2 , wherein the outer member pusher is configured with a channel extending along its length, the channel communicating with the sheath lumen.

12. 12. The intravascular delivery system of claim 11, wherein the outer delivery sheath of the outer member is a flexible outer delivery sheath having a first flexibility along its length and the outer member pusher is a flexible member having a second flexibility along its length, the second flexibility being substantially the same as or greater than the first flexibility.

13. 2. The intravascular delivery system of claim 1, wherein the cooperating mechanism includes a member selected from the group including a mid-shaft locking ring, a square annular ring, and a snap-fit ​​cage, and the cooperating mechanism is attached to the outer surface of the elongate body of the inner member.

14. The intravascular delivery system of claim 13 , wherein the cooperating feature is secured to the outer surface of the inner member in surrounding relationship therewith.

15. The intravascular delivery system of claim 14, further comprising a fenestration system formed in the outer delivery sheath at a proximal end thereof.

16. 6. The intravascular delivery system of claim 5, wherein the microcatheter is formed of a flexible material having differential flexibility along its length, the flexibility of the microcatheter increasing towards its distal end.

17. 17. The intravascular delivery system of claim 16, wherein the microcatheter includes a rectangular wire helical coil extending along the length of the microcatheter, the pitch of the rectangular wire helical coil varying along the length of the microcatheter such that the flexibility of the microcatheter increases toward its distal end.

18. 2. The intravascular delivery system of claim 1, further comprising a rectangular wire helical coil member forming at least a portion of a wall of each of the members selected from the group consisting of the outer delivery sheath of the outer member, the delivery catheter, the elongate body of the inner member, and combinations thereof, wherein the rectangular wire helical coil is formed of a shape memory alloy such as Nitinol or is formed of a radiopaque material.

19. the tapered delivery catheter being a microcatheter formed with a longitudinally extending lumen for sliding along a guidewire; an inner member pusher coupled at a distal end thereof to the proximal end of the inner member; an outer member pusher coupled at a distal end thereof to the proximal end of the elongate body of the outer member; Further comprising: The intravascular delivery system of claim 1 , wherein the outer member pusher is color coated, the color coating having a color distinct from the color of the guidewire and the color of the inner member and the inner member pusher.

20. The intravascular delivery system of claim 1 , wherein the cooperating mechanism includes an annular ring.

21. The intravascular delivery system of claim 1 , wherein the solid distal ring is not expanded and the opening of the split distal ring widens upon relative displacement of the inner member to the proximal coupler of the outer delivery sheath.

22. The intravascular delivery system of claim 1 , wherein the proximal split ring provides a funnel-shaped support for the mouse at the proximal end of the outer delivery sheath.

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