Intravascular delivery system and method for percutaneous coronary intervention

Abstract

The present disclosure directs a catheter extension / pre-dilation system including an outer delivery sheath, an inner member extending within the sheath, and a mechanism for engaging and disengaging the inner member to the sheath. The inner member is configured with a tapered distal tip having a delivery microcatheter and a pre-dilation balloon member attached to the tapered distal tip near the microcatheter. The outer delivery sheath and the inner member are retrofitted for different engagement / disengagement mechanisms. The delivery microcatheter provides improved crossability for the balloon member to the treatment site in a non-invasive, quick and convenient manner. During a cardiac procedure, a guidewire and a guide catheter are advanced to the vicinity of the treatment site within a blood vessel. Subsequently, the inner member and the outer delivery sheath are advanced along the guidewire within the guide catheter to the treatment site in their engaged configuration. Once at the treatment site, the balloon member is inflated for pre-dilation treatment. Subsequently, the inner member is disengaged from the outer delivery sheath and retracted from the outer delivery sheath, and a stent is delivered to the treatment site within the outer delivery sheath.

Description

[0001] Incorporation by reference of related applications

[0002] This PCT patent application claims priority to currently pending U.S. patent application #16 / 793,120 filed on February 18, 2020, which is a continuation-in-part (CIP) of currently pending U.S. patent application #15 / 899,603 filed on February 20, 2018, and a continuation-in-part (CIP) of currently pending U.S. patent application #16 / 132,878 filed on September 17, 2018.

[0003] Currently pending U.S. Patent Application Nos. 16 / 793,120, 16 / 132,878, and 15 / 899,603 are incorporated herein by reference. Technical Field

[0004] The present disclosure relates to minimally invasive devices for treatment within the human vasculature, such as coronary arteries, and more particularly to delivery systems specifically adapted for intravascular balloon angioplasty and coronary stent delivery during percutaneous coronary intervention, enhanced by pre-dilated guide catheter extendability.

[0005] The present disclosure also relates to medical devices designed for non-invasive, convenient, and rapid delivery of various interventional devices, such as pre-dilated balloons or stents, and replacement of catheters in a patient's coronary arteries (or other blood vessels) to facilitate percutaneous revascularization.

[0006] The present disclosure further relates to an intravascular delivery system having a micro-tapered flexible distal tip that enables the interventional device to have exceptional delivery capabilities superior to conventional balloon angioplasty catheters and practical non-invasive crossing capabilities to the site of treatment of lesions.

[0007] The present disclosure also relates to an intravascular guide catheter extension / pre-dilation system that utilizes an inner member (interventional device delivery catheter subsystem) positioned at a predetermined location within an outer member (outer delivery catheter subsystem), wherein the inner member is formed with a distal coil-reinforced tapered portion that abuts against a slightly tapered distal end of the outer member. The inner member is dimensioned to form a micro-contour and substantially "seamless" transition at the junction between the distal ends of the outer member (outer catheter) and the inner member (inner catheter), at the transition point where the distal section of the inner catheter joins or enters the outer member. This configuration greatly facilitates the atraumatic and smooth routing of the inner and outer members as a single unit along the diseased vessel.

[0008] In addition, the present disclosure relates to an intravascular guide catheter extension / pre-expansion system configured with an outer catheter (member) and an inner catheter (member), the inner catheter (member) being movable within and along the outer catheter, wherein the distal tapered soft tip of the outer catheter is formed as an expandable, flexible, low-durometer elastic member having, in its reduced configuration, an inner diameter that is smaller than the outer diameter of the distal section of the inner catheter at the region where it joins the outer catheter. This arrangement achieves a reversible elastic engagement of the outer and inner catheters at their distal ends, which ensures that when the inner catheter has been removed from the outer catheter, the expanded distal end of the outer catheter returns to its reduced outer diameter and reduces (or eliminates) the "fish mouth" defect at the distal junction of the outer and inner members as the system is advanced around the bends of the blood vessel.

[0009] Additionally, the present disclosure relates to an intravascular guide catheter extension / pre-dilation system configured with an outer catheter and an inner catheter that are displaceable relative to one another, wherein the proximal end of the outer catheter has an inlet configuration that provides enhanced reinforcement, enhanced mid-axis stent access, protection against stent embolization, increased flexibility, and improved flow rate of contrast infusion fluid.

[0010] Among other things, the present disclosure relates to an intravascular guide catheter extension / pre-dilation system designed with a mid-axis interconnection (locking) mechanism that is actuated / de-actuated by the physician to either (1) controllably engage an inner member and an outer member for integral movement along a guidewire within the guide catheter, or (2) separate the inner and outer catheters for retracting the inner catheter from the outer member (catheter) as required by the endovascular procedure. The inner member is capable of carrying an interventional device (e.g., a pre-dilation balloon member or stent) attached to its tapered coil-reinforced distal end, and the locking mechanism provides a smooth, reversible engagement / disengagement process. The mid-axis reversible lock also prevents any forward movement of the inner member relative to the outer member during advancement or withdrawal of the system, and ensures that the position of the distal "seamless" transition of the inner and outer catheters remains substantially axially fixed in place during movement of the subject's system.

[0011] In addition, the present disclosure relates to an intravascular guide catheter extension / pre-dilation system, which is configured with a tapered coil-reinforced shaft at its distal end for mounting and carrying a balloon member thereon, and which provides "seamless" access and smooth delivery capability of the balloon member integrated with the coil-reinforced delivery sheath of the external catheter to the desired treatment site.

[0012] The present invention further relates to an intravascular guide catheter extension / pre-dilation system characterized by a single-track microcatheter embodiment with a rapid exchange (RX) feature for applications with short guide wires, wherein the distal tapered soft end of the inner catheter is configured with a coil-reinforced microcatheter that provides additional kink resistance and "pushability" while still maintaining flexibility for navigating tortuous vasculature. Background Art

[0013] Coronary artery obstructive disease or other peripheral vascular diseases are typically treated with balloon angioplasty and / or stent placement. Advancing an intravascular revascularization device (such as a balloon delivery system or stent delivery system) toward the treatment site can be challenging for physicians to detect vessel tortuosity and / or calcification.

[0014] Coronary stents are tube-like devices placed in the coronary arteries supplying blood to the heart to keep the arteries open. They are used to treat coronary artery disease, often called percutaneous coronary intervention (PCI). Stents help improve coronary blood flow, reduce chest pain, and have been shown to improve survival after an acute myocardial infarction.

[0015] Treating blocked coronary arteries with stents essentially follows the same steps as other angioplasty procedures, but with important differences. A compressed stent mounted on a balloon significantly reduces the balloon's flexibility and impairs its smooth advancement through the coronary artery. This can make delivering the stent to the treatment site difficult or impossible and may cause the undeployed stent to fall out of the delivery balloon.

[0016] Intravascular imaging can be used to assess the thickness and hardness (calcification) of the lesion, which will affect the deliverability of the stent. Cardiologists use this information to decide whether to treat the lesion with a stent and, if so, what type and size of stent to use. Bare metal stents and drug-eluting stents are most commonly sold as a whole, with the stent attached to the outside of the balloon catheter in its collapsed (pre-expanded) form.

[0017] Physicians can perform a "primary stent placement," in which a stent is threaded through the blood vessel to the lesion and expanded. However, to facilitate stent delivery in more challenging lesions, the blockage is often pre-dilated before the stent is delivered.

[0018] Pre-dilation is accomplished by piercing the lesion with a standard balloon catheter and dilating it to increase its diameter. A balloon catheter is a flexible tube with an inflatable balloon at its tip, used during the catheterization procedure to widen narrow openings or passages in the body. After pre-dilation, the balloon is removed, and a stent catheter is threaded through the blood vessel to the lesion and expanded, leaving it in place as a permanent implant to "stent" the blood vessel at the lesion.

[0019] Balloon catheters used in angioplasty procedures have either an over-the-wire (OTW) or rapid exchange (RX) design. The balloon catheter is slid into position over a guidewire, which can be inflated through the hub (in the OTW modification) or through the RX port (for the rapid exchange modification of the balloon catheter). In OTW balloon catheters, a concentric lumen for passing the guidewire extends from the proximal hub to the balloon, while in RX-type balloon catheters, a lumen for the passage of the guidewire extends from the RX port within the catheter to the balloon to allow passage of the guidewire.

[0020] Revascularization devices often utilize a guide (or guiding) catheter for delivery of such devices to the treatment site. Advances in using guide catheters alone to "support" coronary revascularization devices can be limited and challenging, particularly when radial access guide catheters are used to place stents.

[0021] To facilitate delivery of revascularization devices to the site of interest, guide catheter extension systems have been designed and used during cardiac surgery.

[0022] For example, guide extension systems such as "Guideliner TM ” manufactured by Teleflex. This guide extension system is described in U.S. Patent #8,292,850 by Root et al. (U.S. Patent #8,292,850) describes a coaxial guide catheter that passes through the lumen of a guide catheter for use in interventional cardiology devices that are insertable into branch arteries branching from the aorta.

[0023] The root coaxial guide catheter is extended through the lumen of the guide catheter and beyond its distal end, and inserted into the branch artery. The root utilizes a guide extension supported by a tapered inner catheter. The inner catheter's purpose is to provide an atraumatic tip to avoid vessel trauma while simultaneously advancing the guide extension into the proximal portion of the coronary vessel to provide additional "support" for stent or balloon delivery.

[0024] Another guide extension system, such as "Guidezilla TM ", designed and manufactured by Boston Scientific. The guide extension system is described in U.S. Patent #9,764,118 authored by Anderson et al. Anderson's guide extension system uses a pusher member having a proximal section with a proximal stiffness and a distal section with a distal stiffness different from the proximal stiffness, and a transition portion that provides a smooth transition between the proximal and distal sections. A distal tubular member is attached to the pusher member and has an outer diameter that is larger than the outer diameter of the pusher member.

[0025] U.S. Patent Application Publication #2017 / 0028178, authored by Ho, describes a guide extension system using a slit catheter that is extendable when inserted into a balloon or stent delivery system. Ho's guide extension also uses a rigid push rod to help deliver the guide extension to the treatment site.

[0026] “Guideliner TM ” system and “Guidezilla TM The system, as well as Ho's, supports the concept of advancing a guided extension system through a guiding catheter and partially down a coronary artery to enable additional "backup" support for delivering a balloon dilatation catheter and / or stent delivery catheter to the intended treatment site.

[0027] The function of these guide extensions is to allow closer access to the lesion to provide additional support when traversing the lesion to be treated with an interventional device. However, despite the additional support, lesions to be treated with pre-dilated balloon catheters or stent delivery systems can still be difficult or nearly impossible to navigate due to fibrosis, calcification, prior stent struts within the lumen, and / or angulation at the lesion site.

[0028] One of the limitations of currently used guide extension devices is that they utilize a relatively blunt and large-caliber cylindrical distal tip. The relatively high-profile distal edge limits the deliverability of the guide extension in many cases and only allows advancement to the proximal or mid-portion of the coronary artery to be treated. Even after balloon pre-dilation of the lesion, it is rarely, if ever, possible to deliver the guide extension to the actual lesion for angioplasty or stent implantation. These “blunt-tip” tubular guide extension devices may fail relatively frequently and may result in serious anatomical complications. Published data indicate that “blunt-tip” tubular guide extension systems may fail in 20% of cases and result in serious coronary artery dissection in approximately 3% of cases.

[0029] U.S. Patent Application Publication #2011 / 0301502, authored by Gill, describes a catheter with a longitudinal extension that allows the diameter of a positioning device to be smaller than the diameter of a stent delivery system. However, the Gill device does not contemplate an inner catheter that allows for easy and atraumatic passage through the lesion to be treated. The Gill system serves merely as a cover for the stent delivery system, which, due to the longitudinal extension, can be removed after the stent delivery system has been advanced.

[0030] While the concept of a tapered member within a guide extension catheter is seen in root devices, prior art systems use very short tapered sections and do not envision the tapered member as an elongated, integrated component of the entire system, nor do they envision that a pre-inflation balloon could be attached to a tapered delivery microcatheter for delivery to the target treatment area. Furthermore, the prior art fails to envision a substantially "flush" interface between the inner catheter and the guide extension within the vessel, or that the inner and outer catheter members would reversibly fit or lock together to allow the entire system to be easily moved as a single device.

[0031] The ROOT literature or other prior art systems do not describe, contemplate, or envision a balloon (and / or stent) delivery system having a very low profile, elongated tip and the ability to extend beyond a lesion of interest, where the low profile, elongated tip would facilitate coaxial delivery of a guide catheter extension / balloon system. Such an embodiment has never been commercialized, and the description of the tapered tip inner device only implies a mechanism for delivering the proximal end of the blunt tip of the guide catheter extension out of the guide catheter, but never as a mechanism for delivering a balloon (and / or stent) beyond a target treatment area in a vessel, nor does it envision that the integral nature and "flush" interconnection of the inner and outer members would allow an outer delivery "sheath" member to pass through the lesion of interest.

[0032] Therefore, devices and methods that allow the distal segment of a tubular guide extension system to be delivered to or ideally beyond the lesion to be treated would have significant advantages over conventional guide extension devices such as "Guideliner™" (Teleflex) or "Guidezilla™" (Boston Scientific).

[0033] None of the conventional balloon catheters (over a guidewire or rapid exchange) are integrated with an external delivery sheath, and none of them utilize a tapered delivery microcatheter at the distal end of the catheter to secure an interventional device (such as a balloon or stent) to the catheter, ensuring atraumatic advancement of the device within the vessel to and beyond the lesion site. Furthermore, none of the conventional balloon catheters are interconnected with the external delivery sheath (guide catheter extension subsystem) via an interconnection mechanism that is actuated to allow the conventional balloon catheter and external delivery sheath to move as a single unit, and deactivated to allow the balloon catheter to be retracted from the external delivery sheath while preventing the balloon catheter from moving forward relative to the external delivery sheath.

[0034] It would be highly desirable and effective to provide an intravascular delivery system that can deliver an interventional device (e.g., a pre-dilated balloon) along with a guide catheter extension subsystem (e.g., an outer delivery sheath) to and beyond a lesion in a substantially non-invasive and convenient manner.

[0035] It would also be highly desirable to provide an intravascular delivery system having an outer catheter and an inner catheter, both of which have a reinforced distal end with a micro-tapered distal end profile with a "seamless" distal end interface to ensure non-invasive cross-over capability of the system with the lesion being treated.

[0036] Additionally, it would be desirable to facilitate percutaneous revascularization procedures by using a balloon attached to the coil-reinforced tapered distal tip of an inner balloon catheter fitted within an outer delivery sheath of an outer catheter, wherein the inner balloon catheter is equipped with a distal elongated tapered coil-reinforced microcatheter at the tapered distal tip to carry interventional devices (pre-dilation balloon and / or stent) to and beyond the lesion to be treated. This would represent a substantial improvement over conventional guide catheter extension and pre-dilation systems. Summary of the Invention

[0037] It is therefore an object of the present invention to provide a medical device for intravascular application that can deliver an interventional device, such as a balloon or stent, to and beyond a coronary obstructive lesion in an efficient and minimally invasive manner.

[0038] Another object of the present invention is to provide an intravascular delivery system using a coaxial, highly flexible delivery catheter device, in which the outer catheter and the inner catheter are connected to each other in a "seamless" manner at their distal ends, having a micro-profile, which is conducive to achieving "cross-ability" of pre-dilated balloons (or other interventional devices) and improving the effective and safe distal delivery of the guide extension device.

[0039] Another object of the present invention is to use a highly flexible coil-enhanced distal tapered elongated microcatheter tip to deliver a pre-dilated balloon (or another interventional device) to and / or beyond a target lesion in a diseased human coronary artery to be treated with angioplasty (or stenting).

[0040] Yet another object of the present invention is to provide a guide catheter extension / pre-dilation system that utilizes an outer catheter (external delivery sheath subsystem) and an inner catheter (interventional device delivery subsystem) mounted and interchangeably connected within the outer sheath of the outer catheter, both of which can be delivered to or beyond a lesion within a blood vessel, wherein the inner catheter has a delivery tapered microcatheter at its distal end with a pre-dilation balloon member (or other interventional device) attached thereto, which slides over a guide wire in a substantially atraumatic manner.

[0041] It is also an object of the present invention to provide a guide catheter extension subsystem (external member) integrated with a pre-dilation balloon (or other interventional device) subsystem (internal member), wherein the external member and the internal member are coupled to each other (by a locking mechanism) to be shifted as a whole (as a "whole system") along the guide wire to the lesion site. After the pre-dilation procedure, the guide catheter extension subsystem (configured with an external delivery sheath) is unlocked from the internal member and, if necessary, can be advanced beyond the lesion. Subsequently, the internal member (interventional device delivery subsystem) can be withdrawn. If the surgical procedure requires, the external delivery sheath of the external member can be retained in the guide catheter to enhance the delivery capability of the stent (or other interventional device tapered) to the lesion site within the external delivery sheath. After the stent (or other interventional device) has been delivered to the lesion and deployed for final treatment, the external delivery sheath can be subsequently withdrawn.

[0042] Furthermore, it is an object of the present invention to provide a guide catheter extension / pre-dilation system equipped with a "locking mechanism" operably connected between an inner member and an outer member (outer sheath) to provide integral passage of the inner member and the outer member as a single unit for convenient and safe delivery of the pre-dilation balloon and the outer sheath to and beyond the treatment site.

[0043] It is also an object of the present invention to provide a guide extension system configured with a pre-dilated balloon (or other interventional device) delivery catheter that can be delivered to a treatment site within a vascular structure in an atraumatic manner to facilitate passage of the balloon (or other interventional device) and the guide extension system therethrough, thereby expediting cardiac surgery, allowing percutaneous coronary intervention to be performed with a lower radiation dose than using conventional systems, and with the added advantage of virtually no risk of stent embolization or drug loss from the stent delivery system (when using drug-eluting stents).

[0044] It is also an object of the present invention to provide an intravascular guide catheter extension / pre-dilation system configured with a coaxial inner catheter and outer catheter, displaceable relative to each other and reinforced by coil reinforcements along their length, but with increasing flexibility and capable of achieving improved contrast agent infusion flow rates and embolic prevention, wherein the tapered distal end of the outer catheter can be elastically stretched to form a secure contact with the distal segment of the inner catheter and an almost flush (smooth) outer surface at the interface between the inner catheter and the outer catheter.

[0045] The present system and method address an intravascular delivery system configured for controllable displacement along a guidewire in a vessel of interest. The disclosed system is formed with a proximal segment, a distal segment, and an intermediate segment located between the proximal segment and the intermediate segment. The current system includes an outer member formed by an elongated outer delivery sheath having a flexible, substantially cylindrical profile, which defines a sheath lumen having a proximal end and a distal end. The outer delivery sheath extends between the intermediate segment and the distal segment and is 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 pattern between the distal and proximal edges of the tapered outer tip. The wall of the tapered outer tip has an inner diameter and an outer diameter. The inner and outer diameters of the wall of the tapered outer tip gradually decrease in size from the proximal edge to the distal edge of the tapered outer tip. The proximal (wire or hypodermic tube) element (push or pull) of the tubular structure connected to the outer member can be low profile and "flexible" (not "rigid") to allow for enhanced compliance within the guide catheter and a lower profile than the rigid "push" element (according to the root) in traditional guide extension catheters. This is due to the "pushability" of the "system as a whole" achieved by the locking and integral connection between the outer catheter (and its hypodermic tube push / pull element) and the inner catheter (guide extension tube).

[0046] The disclosed system also includes an inner member (inner catheter) having an elongated body defining an internal passage extending along its longitudinal axis. The inner member extends internally along the sheath lumen of the outer member (outer catheter) in a controlled relationship with the outer delivery sheath. The tapered distal section of the elongated body of the inner member has an outer diameter and is configured with a tapered delivery catheter of the elongated body of a predetermined length. The tapered delivery catheter of the inner member can move beyond the distal end of the outer sheath. Importantly, 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 section of the inner member in the area where the two elements form a distal junction.

[0047] The interconnection mechanism is operably coupled between the inner member and the outer member and controllably actuated to operate the guide catheter extension / pre-expansion subsystem in an engaged or disengaged operating mode. In the engaged operating mode, the inner member and the outer member of the guide catheter extension subsystem are engaged for controllable common displacement along the guide wire. This also allows for enhanced "propulsability" of the subject's system (the outer member is connected and locked to the inner member), even if the connected pusher (push / pull element) of the outer member has a micro-profile and is flexible (as flexible as or softer than the outer tubular sheath of the outer catheter). In the disengaged operating mode, after pre-expansion treatment or stent delivery, the inner member and the outer member are separated to retract the inner member from the outer member.

[0048] The distal section of the inner member engages the inner surface of the tapered outer tip of the sheath lumen at its outer surface. The size transition between the outer diameter of the sheath lumen outer tip and the outer diameter of the distal tip of the inner member forms a substantially flush interface transition therebetween.

[0049] The tapered outer tip of the outer member has a resiliently expandable structure. At its proximal end (also referred to herein as the mid-shaft portion of the outer member), the outer sheath is provided with an entry opening whose circumference exceeds the circumference of the tubular body of the outer sheath. In some embodiments, the entry 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 the distal end of the outer member. The distal soft tip encapsulation material is a flexible, low-durometer elastomeric material having a gradient of hardness values ​​that increases from the distal end to the proximal end of the sheath.

[0051] The outer member also includes a distal lubricious liner sandwiched between the outer surface of the outer sheath and the inner surface of the distal soft tip potting material.

[0052] The delivery catheter is preferably a microcatheter. The microcatheter is formed of a flexible material and may have varying flexibility along its length, wherein the flexibility of the microcatheter increases toward its distal end.

[0053] The balloon member is attached to the tapered distal section of the inner member, adjacent to the tapered delivery microcatheter; and an inflation lumen extends within the inner member between the balloon members at the proximal and distal sections to provide a fluid pathway between the external balloon expansion system and the balloon members. The balloon member can assume an expanded configuration or a collapsed configuration. In the collapsed configuration, the balloon member moves within the blood vessel. After being positioned at least in alignment with the treatment site for a pre-dilation procedure, the balloon member is controllably transitioned to the expanded configuration.

[0054] The elongated body of the inner member and the microcatheter are reinforced along their length by coils.

[0055] The push / pull element of the outer catheter is configured with a flat portion at its distal end that is fixed to the proximal end of the outer sheath of the outer catheter. Preferably, the pusher / puller of the outer member is configured with a channel extending along its length that is in fluid communication with the sheath lumen to prevent embolism. This proximal (push and pull) element connected to the outer sheath tubular structure of the outer catheter can be low-profile and "flexible" (not "rigid") to allow for better compliance inside the guide catheter and a lower profile than rigid "push" elements in traditional guide extension catheters (such as the root).

[0056] The interconnection mechanism may 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 may include a distal uninterrupted ring and an intermediate split ring positioned a predetermined distance from the uninterrupted ring, while the cooperating member includes a member selected from the group consisting of an intermediate shaft locking ring, a square ring, a snap cage, and other similar members. The cooperating member is fixed to the outer surface of the elongated body of the inner member. When the cooperating member engages and locks between the distal uninterrupted ring and the intermediate split ring in a snap-fit ​​manner, a locked engagement between the outer member and the inner member is achieved. The proximal push / pull element and coupler of the outer catheter may be made of a memory metal (e.g., nitinol) to prevent deformation during antegrade or retrograde movement of the outer member and to prevent any deformation of the mid-shaft coupler (also referred to herein as the proximal coupler) during passage of a stent or other device through the mid-shaft portion of the outer catheter.

[0057] The proximal coupler also includes a proximal beveled split ring at its proximal end that reinforces the funnel-shaped proximal inlet of the outer member and prevents damage or permanent deformation of the funnel-shaped proximal inlet due to displacement of the inner components or the stent delivery system within the funnel. The coupler and the mid-shaft inlet can have an access opening (or "mouth") having a circumference greater than the circumference of the flexible tubular outer sheath structure of the outer member.

[0058] The subject's intravascular system also includes a guidewire that is advanceable within a vessel of interest to at least a treatment site, wherein the guide catheter extension subsystem is configured for controllable displacement along the guidewire. In one embodiment of the subject's system, an elastic outer sheath surrounds the inner member at least at its proximal end and surrounds a pusher / puller of the inner member at least at its distal end. The proximal end of the inner member is connected to the pusher / puller by fusing the elastic sheath to the length of the proximal end of the inner member and tightly supporting the pusher / puller of the inner member within the elastic sheath.

[0059] The push / pull element of the outer catheter (or its outer sheath) can be colored to be distinguishable from the push / pull element of the inner catheter and to be a color different from the usual gray or silver, and to be distinguishable from the gray or silver of the coronary guidewire. Alternatively, for the surgeon's convenience, the elastic outer sheath of the inner member can be colored to distinguish the push / pull element of the inner member from the color of other elements in the subject's system.

[0060] These and other objects and advantages of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1schematically illustrates a guide catheter extension / pre-dilation system of the present disclosure being advanced to a target site within a coronary artery;

[0062] Figure 2A-2C The present invention is schematically described as follows: Figure 2A shows the assembled inner and outer conduits, Figure 2B Details of the internal catheter, and Figure 2C The middle section of the disclosed system is described in detail;

[0063] Figures 3A-3D represents the middle section of the disclosed internal conduit, Figure 3A A longitudinal section of a gas-lumen hypodermic tube interconnected with a gas-lumen distal rod in an inner catheter is shown, Figure 3B Detailed illustration of a longitudinal cross section of a cut portion of a gas-filled lumen hypodermic tube. Figure 3C shows a longitudinal section of the inner catheter depicting the RX guidewire port formed in the distal shaft of the inflation lumen, and Figure 3D Shown Figure 3C An isometric view of the RX port portion of the inner catheter shown in;

[0064] Figure 4 showing a longitudinal section of the inner catheter, detailing the distal end of the inflation hypodermic tube at the connection to the distal rod of the inflation lumen;

[0065] Figures 5A-5C depicts a distal section of the disclosed system, Figure 5A Depicting an inflated balloon member, Figure 5B shows the deflated balloon member, and Figure 5C The inflation lumen / balloon connection is described in detail;

[0066] Figure 6A-6B Depicts a longitudinal cross-section of the distal section of the inner catheter of the present disclosure, detailing the 3 mm distal and proximal tapers of the balloon ( Figure 6A ) and the 6 mm distal and proximal tapers of the balloon ( Figure 6B );

[0067] Figure 7 The distal tip of the external catheter is depicted;

[0068] Figure 8A-8B The interface of the inner and outer catheters at their distal ends is detailed, wherein Figure 8A represents the tapered distal end of the inner catheter, Figure 8A represents the tapered distal end of the inner catheter. Figure 8B The connection point between the inner and outer ducts is depicted on a slightly exaggerated scale;

[0069] Figures 9A-9D represents an alternative embodiment of an elastically stretchable distal tip of an outer catheter configured with an expandable split ring ( Figure 9A ), expandable end stent ( Figure 9B ) and slits ( Figures 9C-9D );

[0070] Figures 10A-10G Depicting a side view of an alternative embodiment of a proximal section of an external body catheter ( Figure 10A 、 10B , 10D, 10F) and isometric views ( Figure 10C 、 10E , 10G);

[0071] Figures 11A-11C The design of the coupler on the proximal side of the external catheter is detailed, wherein Figure 11A Depicting an isometric view of a flat hypodermic tube pusher, Figure 11B is a stereoscopic view of the proximal end of the external catheter. Figure 11B is a stereoscopic view of the proximal end of the external catheter. Figure 11C depicts a side view of a coupler having a snap-fit ​​locking mechanism at the proximal end of an outer catheter;

[0072] Figures 12A-12C depicts an alternative embodiment of a proximal section of an external body catheter, Figure 12A is an isometric view of the near-side coupler, Figure 12B is an isometric view of the packaged near-side coupler, and Figure 12B is an isometric view of the packaged near-side coupler, Figure 12C is a side view of the packaged near-side coupler;

[0073] Figures 13A-13B A side view of yet another embodiment of a proximal coupler proximal to an outer catheter is shown ( Figure 13B ) isometric view ( Figure 13A );

[0074] Figures 14A-14B Depicting an embodiment of a weld ring at the proximal inlet of an external catheter, Figure 14A shows a fused ring coupler, Figure 14A shows a fused ring coupler, and Figure 14B An encapsulated fused ring coupler is shown;

[0075] Figures 15A-15D Depicting a further alternative embodiment of a proximal coupler of an outer catheter, Figures 15A-15B The side view and isometric view of the circular outline funnel-shaped window, and Figures 15B-15D They are the side view and isometric view of the triangular funnel-shaped window opening;

[0076] Figures 16A-16C Represents the concept of flushing the lumen of a subcutaneous injection tube pusher. Figure 16A An isometric view depicting the proximal coupler of an external catheter coupled to a pusher, Figure 16B yes Figure 16A An isometric cutaway view depicting the flow path in the propeller. Figure 16C The process of injecting irrigation fluid between the inner and outer catheters is shown.

[0077] Figures 17A-17C The present invention depicts a central rod ring locking mechanism, wherein Figure 17A shows the "lock-to-disengage" mode of operation, Figure 17B shows the "locked engaged" mode of operation, and Figure 17C represents the annular ring in the locking mechanism of the present disclosure;

[0078] Figures 18A-18B Detailed description Figure 17A and 17B The annular ring locking mechanism of the present disclosure shown in Figure 18A Depicts a configuration useful with ( Figure 17C ) annular ring engaging the locking recess of the proximal coupler, and Figure 18B is a longitudinal cross-sectional view of the interlocking inner / outer catheters;

[0079] Figures 19A-19C Depicts an alternative embodiment of the disclosed locking mechanism featuring a mid-bar "square" ring. Figure 19A An inner catheter with an annular locking mechanism is shown, Figure 19B The ring of the inner catheter is shown stuck in the proximal coupler of the outer catheter, and Figure 19C A cross-sectional view of a square ring is depicted;

[0080] Figures 20A-20C Depicts an alternative "snap-cage" style locking mechanism, Figure 20A Shown is an inner catheter with a fused cage lock. Figure 20B The fused cage of the inner catheter is shown locked into the proximal coupler of the outer catheter, and Figure 20C It is a perspective view of the fusion cage element;

[0081] Figure 21 is a side view of another embodiment of a proximal coupler of an outer catheter having two locking grooves;

[0082] Figures 22A-22B A single-track microcatheter embodiment representing the disclosed system. Figure 22A depicts an isometric view of a single-track microcatheter embodiment, and Figure 22B A side view taken along line AA is shown.

[0083] Figures 23A-23C The present invention is described in detail in the embodiment of the single track microcatheter. Figure 23A An isometric view of the proximal section of the inner catheter connected to the inner catheter hypodermic tube pusher is shown, Figure 23B Details of the proximal end of the thruster, at a slightly enlarged scale, and Figure 23C is a side view of a proximal section of an inner catheter connected to a hypodermic tube pusher; and

[0084] Figure 24A and Figure 24B Depicted are an isometric view and a side view, respectively, of an embodiment of a coil-augmented balloon catheter of the disclosed system. DETAILED DESCRIPTION

[0085] like Figure 1-24B As described in the accompanying drawings, the intravascular delivery system 10 includes a guide catheter extension subsystem (also referred to herein as an outer catheter or outer member) and an interventional device delivery subsystem (also referred to herein as an inner catheter or inner member), which cooperate with each other under the control of the surgeon during cardiac surgery. Although the interventional device delivery subsystem can be used to deliver various cardiac interventional devices, in one embodiment, which is merely an example and does not limit the scope of the present invention to this particular embodiment, the interventional device delivery subsystem of the present invention will be further described as being suitable for delivering a balloon member for performing a pre-dilation procedure.

[0086] In the exemplary embodiment described herein, the system 10 may be referred to herein as a guide catheter extension / pre-dilation system, which may be used in conjunction with a guide wire 12 and a guide catheter 14 for cardiac surgery. Figure 1 As shown, in the initial stages of cardiac surgery, the surgeon moves a guidewire (GW) 12 into a blood vessel 16. A guide catheter 14 is advanced along the guidewire 12 through the blood vessel 16 (such as, for example, the aorta) to a position adjacent to an opening 18 of a coronary artery 20. The guidewire 12 can be used to guide the guide catheter 14 during cardiac surgery, and then the guide catheter extension / pre-dilation system 10 (within the guide catheter 14) can be extended within the artery 20 toward a target location 22, as will be described in detail in the following paragraphs.

[0087] like Figure 2A-2C As shown, the guide catheter extension / pre-dilation system 10 includes a balloon catheter subsystem 34 (also referred to herein as an inner catheter, inner member, or pre-dilation subassembly) and a guide catheter extension subsystem 36 (also referred to herein as an outer catheter). The inner catheter 34 interacts with the outer catheter 36 and can be engaged or disengaged with the outer catheter 36 as needed for cardiac surgery.

[0088] The system 10 includes a proximal section 38, a distal section 40, and an intermediate section 42 extending between and interconnecting the proximal and distal sections 38, 40. A pre-expanded balloon member 44 is carried in the distal section 40 of the inner catheter 34. The distal section 40 of the inner catheter 34 may also be configured with an elongated, tapered microcatheter 46, which will be described in detail in the following paragraphs.

[0089] like Figure 1 As shown, the guide extension / pre-dilation system 10 is extended within the lumen (interior passageway) 48 of the guide catheter 14. To reliably reach the target location 22, and in some cases, to pass beyond the target location 22, the guide extension / pre-dilation system 10 is advanced through the guide catheter 14 beyond the distal end 50 of the guide catheter 14 and deep into the coronary artery 20. The system 10 provides sufficient accessibility of the pre-dilation balloon 44 to the target location 22 by extending beyond the distal end 50 of the guide catheter 14, and stabilizes the positioning of the guide catheter 14 by extending beyond the opening 18 of the coronary artery 20, allowing for improved ease of entry into the coronary artery 20 and accessibility of the system 10 to the target location 22.

[0090] like Figure 1 、 Figure 2A-2B 、 Figure 3C-3D 、 Figure 4 、 Figures 5A-5C and Figure 6A As shown, the guidewire 12 extends inside the guide catheter extension / pre-dilation system 10 and exits the system 10 with the distal end of the GW 12 beyond the distal-most end 52 of the distal section 40 and the proximal end of the GW 12 at the intermediate section 42 .

[0091] In operation, the inner catheter 34 and the outer catheter 36 are connected to each other to advance (as a single unit) along the guide wire 12 within the guide catheter 14 located within the blood vessel 16 and extend beyond the distal end 50 of the guide catheter 14 to the target lesion 22. Once the balloon catheter subsystem (inner member) 34 reaches the lesion 22 and the balloon member 44 is positioned to align with the lesion 22, the intended pre-dilation procedure can be performed. Once the pre-dilation has been performed, the outer catheter (also referred to herein as the outer member) 36 can be advanced through 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 is separated from the outer catheter 36 to be withdrawn from the outer catheter.

[0092] Alternatively, after the pre-dilation procedure has been performed, the inner catheter 34 can be separated from the outer catheter 36 while the outer catheter 36 is advanced through the dilated lesion. Additionally, after the pre-dilation has been performed and the inner catheter 34 has been removed, the outer catheter 36 can be left near the lesion.

[0093] In any case, the outer member (catheter) 36 held near the pre-dilated lesion can be used to deliver the stent inside the outer member (catheter) 36 to the lesion. Once the stent is installed (deployed) at the lesion, the outer member 36 is removed from the guide catheter 14.

[0094] As will be presented in further paragraphs, in the disclosed system, inner catheter 34 is prevented from forward displacement within outer catheter 36. Only rearward or removal displacement of inner member 34 relative to outer member 36 is permitted to support retraction of the inner member from the outer member after lesion pre-dilation.

[0095] refer to Figure 2A-2C The proximal section 38 of the guide extension / pre-expansion system 10 is guided by the balloon inflation hub 56 of the inner member 34 (at Figure 2B ) and the proximal end 58 of the outer member 36 are shown.

[0096] refer to Figure 2B 、 Figures 3A-3D 、 Figure 4 and Figure 5C The inner member (sometimes also referred to herein as a balloon catheter subsystem or pre-expansion balloon delivery subsystem) 34 is configured with an inner inflation channel 60 extending between the inflation hub 56 and the pre-expansion balloon member 44. The inner inflation channel 60 serves as a guide for the balloon inflation system 62 (in the Figure 2B Schematically shown in the figure) and the passage between the balloon member 44 for filling with air to achieve controlled inflation / deflation of the balloon member 44 as prescribed by the cardiac surgery

[0097] The internal inflation channel 60 is formed by an inflation lumen hypodermic tube 64 and an inflation lumen distal stem 66 that are superimposedly connected to each other in a fluid-tight manner.

[0098] The inflation hub 56 at the proximal end 68 of the inner member 34 is provided with an internal tapered channel 70 that is connected to the balloon inflation system 62 (eg, Figure 2B Schematically shown in FIG).

[0099] The balloon inflation system 62 can be a manual or automated system. In a preferred automated embodiment, the balloon inflation system 62 includes an electronic subsystem, a pneumatic subsystem, and control software with a corresponding user interface. Under the control of the control software, the electronic subsystem supplies power to an electromagnetic pressure valve (which is fluidically connected to the balloon inflation hub 56) to control the pressurization / decompression of the balloon member 44 using a fluid or air flow.

[0100] like Figure 2BAs shown, the inner tapered passage 70 of the balloon inflation hub 56 is configured with a distal opening 74 that is coupled to the inflation lumen hypodermic tube 64. The proximal end of the inflation lumen hypodermic tube 64 is coupled to the distal opening 74 of the inner tapered passage 70 of the balloon inflation hub 56 in a fluid-tight manner to support the passage of inflation air between the inflation system 62 and the balloon member 44.

[0101] like Figure 2B and Figure 4 As shown, the inflation lumen hypodermic tube 64 extends along the length of the proximal section 38 and a portion of the intermediate section 42 of the disclosed system 10 and terminates at its distal end 78 in the distal section 40 .

[0102] like Figure 2B As shown, a flexible serrated member 80 is provided at the proximal end 76 of the inflation lumen hypodermic tube 64, which is coupled 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 hypodermic tube 64 and provides flexible bending of the structure when operated by the surgeon.

[0103] like Figure 2A-2C 、 Figures 3A-3D 、 Figure 4 and Figure 5C As shown, the inflation lumen distal rod 66 extends along the intermediate section 42 between the proximal section 38 and the distal section 40 and terminates at the distal section 40 . Figure 3A The connection between the inflation lumen hypodermic tube 64 and the inflation lumen distal rod 66 is detailed. The inflation lumen hypodermic tube 64 does not extend all the way through the inner member 34, but terminates at its distal end 78 (e.g., Figure 2B and Figure 4 shown).

[0104] refer to Figure 3B-3D The inflation lumen hypodermic tube 64 has a cut distal portion 90 that is coaxially enclosed by the wall of the inflation lumen distal rod 66, so that the inflation lumen hypodermic tube 64 and the inflation lumen distal rod 66 together provide sealed fluid communication between the balloon inflation system 62 and the interior chamber 92 of the balloon member 44, as shown in FIG. Figures 5A-5C As shown, it is used to control the inflation / deflation of the balloon member 44 according to the requirements of the cardiac surgery.

[0105] Figure 2B and Figure 3C-3DThe inflation lumen distal rod 66 is shown configured with a rapid exchange (RX) guidewire (GW) port 94, with the proximal end 98 of the GW lumen 96 beginning at the port 94. The GW lumen 96 extends within the inflation lumen distal rod 66 along the entire length of the distal section 40 of the inner catheter 34 between the RX GW port 94 and the distal section 40. The GW lumen 96 forms an internal passageway and corresponds at its proximal end 98 to the RX GW port 94 and at its distal end 100 to the distal-most end 52 of the distal section 40 of the inner member 34. Figures 6A-6B As shown, at the distal section 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 tapered portion 104 that may be in the form of a delivery microcatheter 46.

[0106] refer to Figure 2A-2B 、 Figures 5A-5C 、 Figure 6A-6B and Figures 24A-24B , the inner catheter (also referred to herein as the balloon catheter subsystem) 34 is configured with a tapered distal portion (sometimes referred to herein as a tapered distal tip) 162 at the distal section 40. The tapered distal portion 162 is equipped with a pre-expansion balloon member 44, which is fixed to the tapered distal portion 162 near the microcatheter 46. The pre-expansion balloon member 44 is fixed to the tapered distal portion (tip) 162 of the inner member to support the pre-expansion / stent implantation procedure required for the patient's heart treatment.

[0107] The balloon member 44 has a proximal portion 112 and a distal portion 114. The balloon member 44 is attached (fixed) at the distal section 40 proximate to the delivery microcatheter 46, wherein the proximal portion 112 of the balloon member 44 is coupled to the distal end 102 of the inflation lumen distal shaft 66 and the distal portion 114 of the balloon 44 is connected to the outer surface of the microcatheter 46.

[0108] like Figures 5A-5C As shown, the pre-dilation balloon 44 is attached with its proximal portion 112 to a proximal portion 204 of the distal tip 162 adjacently juxtaposed to the outer tip 164 of the sheath 120 and with its distal portion 114 to the distal end 166 of the distal portion (tip) 162 of the inner member 34 .

[0109] The balloon member 44 can intermittently assume a deflated (collapsed) and inflated (expanded) configuration. The deflated (collapsed) configuration is used during insertion and / or withdrawal of the disclosed system relative to a blood vessel. The balloon is inflated (expanded) when in place (at the target site 22) to dilate the vessel and compress plaque for a pre-dilatation procedure, or (when a stent is delivered to the treatment site on the balloon) for a stent implantation procedure. When inflated, the balloon 44 assumes a Figure 2A-2B 、 Figure 5A 、 Figure 5C 、 Figure 6A-6B and Figures 24A-24B The inflated / opened configuration shown is used for pre-dilation of diseased blood vessels. When deflated, the balloon member 44 presents Figure 5B Deflated configuration shown.

[0110] The balloon 44 can have a smooth surface or a "chocolate" configuration. A "chocolate" balloon catheter is an over-the-counter (OTW) balloon dilation catheter with a braided shaft and an atraumatic, tapered tip. When inflated, the balloon is constrained by the nitinol structure, which forms small pillows and grooves in the balloon.

[0111] Now refer to Figure 2A 、 Figure 2C 、 Figure 5A – Figure 5C 、 Figure 7 、 Figure 8A-8B 、 Figure 9A 、 Figure 9C – Figure 9D 、 Figure 10A – Figure 10G 、 Figure 11C 、 Figure 12B – Figure 12C 、 Figure 13A – Figure 13B 、 Figure 14B 、 Figure 15A – Figure 15D 、 Figure 16A – Figure 16B 、 Figure 17A – Figure 17B 、 Figure 18A – Figure 18B 、 Figure 19B 、 Figure 20A-Figure 20B 、 Figure 21 and Figures 24A-24B As shown, the outer catheter (also referred to as the guide catheter extension subsystem) 36 is formed with a cylindrical outer delivery sheath 120 having an inner channel 122 extending therethrough. A coupling mechanism 130 is formed at a proximal end 132 of the cylindrical sheath 120 in surrounding relation thereto.

[0112] At the proximal end 58, the outer catheter 36 includes an outer member pusher (also referred to herein as a pusher / puller) 134, such as Figure 10B Tu-10G, Figures 11A-11C 、 Figures 12A-12C 、 Figures 13A-13B 、 Figures 14A-14B 、 Figures 15A-15D 、 Figures 16A-16B 、 Figures 17A-17B 、 Figures 18A-18B 、 Figure 19B22 , in one embodiment, the outer member pusher can be an uninterrupted wire comprising: a proximal section 136 that can have a round wire, and a flat distal section 138 that can be welded or otherwise fixedly attached to the proximal end 132 of the sheath 130. In another embodiment, the push-pull element 134 can be configured with a hypodermic tube.

[0113] Alternatively, the round pusher wire may be welded to the flat wire, which in turn is welded or otherwise fixedly secured to the proximal end 132 of the sheath 120 .

[0114] In yet another alternative embodiment of the outer member 36 , the round wire may be welded or otherwise fixedly secured to two flat wires, which in turn are welded or otherwise fixedly secured to the proximal end 132 of the sheath 120 .

[0115] The flat profile of the pusher wire portion is welded to the proximal coupler 130 of the outer sheath 120 so that, as required by the procedure, the pusher wire does not hinder the rotational or longitudinal movement of the inner catheter 34 within the proximal coupler 130 and sheath 120 of the outer member 36 when the inner member 34 is inserted into the outer member (catheter) 36. The proximal push-pull element 134 advances or retracts the outer tubular sheath 120 and is preferably flexible (non-rigid). The pusher / puller 134 can be flexible (non-rigid) with a flexibility along its longitudinal axis comparable to or exceeding the flexibility of the tubular outer delivery sheath 120 of the outer catheter 36.

[0116] like Figure 10F As shown, the pusher 134 of the outer catheter can be equipped with a proximal handle 140 at its proximal end, thereby facilitating the surgeon performing a coronary intervention procedure to manipulate the outer member 36 so as 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 vessel.

[0117] The proximal (wire or hypodermic tube configuration) push-pull element 134 of the tubular structure 120 connected to the outer member achieves enhanced compliance within the guide catheter and a lower profile (according to Root) than the rigid "push" elements in traditional guide extension catheters by being micro-profiled and flexible (not "rigid"). This is due to the "pushability" of the "whole system" achieved by the locking integral connection between the outer catheter (and its hypodermic tube pusher element) and the inner catheter (the guide extension tube).

[0118] In addition, the inner catheter (inner member) 34 can be equipped with an inner member pusher (also referred to herein as a pusher / puller) 142 (e.g., Figure 2A), which can be attached to the inflation hub 56 to facilitate the withdrawal of the inner member 34 from the outer member 36 as needed for coronary intervention surgery, and to control the engagement / disengagement between the inner member 34 and the outer member 36 for various stages of cardiac surgery. In order to facilitate the surgeon in performing the surgery, the inner member pusher 142 can be formed with a handle of the inner member pusher.

[0119] The handles of the pushers for the inner and outer members can be configured with a mechanism that allows additional releasable locking of the inner and outer members to each other (described in detail in U.S. patent application #15 / 899,603, which is incorporated herein by reference) to enhance the overall fit of the inner and outer members in the engaged mode of surgical operation.

[0120] The inner member 34 can be in an OTW configuration or an RX configuration. In one embodiment described in detail herein, the guide wire 12 extends through the RX GW port 94 formed at the proximal end of the tubular inflation lumen distal rod 66, into and along the internal channel 146 of the GW lumen 96, as shown in FIG. Figure 3C-3D and Figure 4 At the distal section 40 of the disclosed system 10, the guidewire 12 extends within the GW lumen along the tapered delivery microcatheter 46 (at the tapered portion 104) and exits the distal end 100 of the GW lumen 96 at the distal-most end 52 of the inner member 34, as shown. Figure 2A – Figure 2B 、 Figure 5A – Figure 5B and Figure 6A – Figure 6B shown.

[0121] The outer delivery sheath 120 of the outer member 36 is made of a flexible cylindrical tubular body 150 that extends substantially along the length of the intermediate section 42 of the system 10. By manipulating the outer member pusher 134, the surgeon actuates the outer delivery sheath 120 and the inner member 34 to advance integrally along the guide tube 14. When a pre-dilation procedure has been performed (described in detail in further paragraphs), the surgeon controls the desired linear rearward displacement of the inner member 34 relative to the sheath 120 of the outer member 36 by manipulating the outer member pusher 134 and / or the inner member pusher 142.

[0122] The interface between the outer end 164 of the sheath 120 and the distal end 162 of the inner member 34 is as shown in FIG. Figure 8A-8B and Figures 9A-9D As shown, displacement of the distal tip 162 of the inner member 34 relative to the outer tip 164 of the sheath 120 is facilitated, and ultimately facilitated, as required for cardiac surgery.

[0123] The distal end 160 and the outer end 164 of the sheath 120 are formed of a flexible material that allows for simplified retraction of the distal end 162 of the inner member 34 therethrough. A flat wire helical coil can be used for the distal end 160 and the outer end 164 of the sheath 120.

[0124] The sheath 120 of the outer catheter 36 is configured with an inlet "opening" (or "mouth") 210 at its proximal end 132, the circumference of which exceeds the circumference of the outer member flexible tubular sheath 120, as shown in FIG. Figures 10A-10G The entrance 210 (also referred to herein as the "mouth") into the internal passage 122 of the sheath 120 can be configured in various modifications. For example, Figure 10A As shown, the inlet 210 has a funnel shape 211 with an eccentric opening (e.g. Figure 10A ), or with a concentric blunt profile (as Figure 10B-10C ), or with concentric slopes (as Figure 10D – Figure 10E ), or alternatively have a concentric concave profile (as Figure 10F – Figure 10G The pusher 134 is fixed at a predetermined point of the proximal entrance 210 of the funnel-shaped outer catheter.

[0125] like Figure 2A 、 Figure 2C 、 Figure 7 and Figure 8A-8B As shown, the outer delivery sheath 120 of the outer catheter 36 extends between a proximal end 132 located at the intermediate section 42 of the system 10 and a distal end 160 located at the distal section 40. At the distal section 40 of the guide catheter extension / pre-dilation system 10, the inner member 34 is configured with a tapered configuration 104 having a distal tapered portion (also referred to herein as a distal tapered tip) 162, which can be formed with a microcatheter 46, as shown. Figure 2A – Figure 2B 、 Figure 5A – Figure 5B 、 Figure 6A – Figure 6B 、 Figure 8A 、 Figure 22A – Figure 22B and Figure 24A – Figure 24B As shown. The microcatheter 46 is an elongated, thin member having a length in the centimeter range, for example, 1-3 cm. The microcatheter 46 has a tapered, conical profile at its distal end 52 with a diameter not exceeding 1 mm. The microcatheter 46 can be integrally formed with the tapered distal tip 162 of the inner member 34.

[0126] like Figure 2A 、 Figures 5A-5C 、 Figure 7and Figures 8A-8B As shown, at the distal end 160, the outer delivery sheath 120 is formed with an outer tip 164 having a tapered conical profile that can interconnect with the distal tip 162 of the inner member 34 of the catheter. The outer tip 164 of the outer member 36 provides a smooth distal tapered transition between the distal end 160 of the sheath 120 and the distal segment 40.

[0127] exist Figure 2A 、 Figure 5A-5B 、 Figure 6A-6B 、 Figure 8A-8B 、 Figures 22A-22B and Figures 24A-24B 1 : The distal tip 162 of the inner catheter 34 has a tapered configuration that gradually changes from the point of interconnection with the distal end 164 of the sheath 120 to the distal end 166 of the distal tip 162. The microcatheter 46 extends from the distal end 166 of the distal tapered portion 162 of the inner member 34 (approximately 1-3 cm in length) in an integral connection with the inner member and terminates at the distal-most end 52.

[0128] The guide catheter extension / pre-dilation system 10 of the present disclosure can be constructed to be more flexible in the distal portion, have a substantially lower profile, and be more flexible in the distal portion of the guide catheter extension subsystem (external delivery sheath) by differentiating the flexibility of the microcatheter, wherein the differentiation of the flexibility of the microcatheter is achieved by the following means: changing the hardness of the plastic (polymer) component from the proximal portion to the distal portion of the external delivery sheath (i.e., adopting a higher hardness in the proximal portion relative to the distal portion), and / or changing the winding frequency (pitch) of the helical coil in the microcatheter 46 in the direction from the proximal portion to the distal portion, so that the distal portion of the microcatheter 46 is more flexible and easier to track than the proximal portion of the microcatheter delivery device.

[0129] The system 10 may also include a radiopaque wire so that the balloon member 44, microcatheter 46, and outer delivery sheath 120 are easily visualized using fluoroscopy. Figure 5A 、 Figure 6A-6B ) are provided with radiopaque markers 264, 266 near the proximal portion 112 and the distal portion 114 of the balloon 44. The markers 264, 266 allow the surgeon (operator) to visualize the positioning of the balloon member 44 relative to the lesion site 22.

[0130] Additionally, the distal-most tip 52 of the microcatheter delivery portion 46 and the distal end 160 of the sheath 120 may have one or more radiopaque markers 268, 270 (e.g., Figure 2B and Figure 5A) to allow the surgeon to distinguish the radioactive marker, which is particularly important when the obstructive lesion is passed through the microcatheter and the balloon member carried by the microcatheter is held in place.

[0131] like Figure 7 As described in detail in

[15] , in one embodiment, the outer catheter 36 is configured with a system of catheter shaft coil reinforcements 170 disposed on (or embedded in) the interior surface 152 of the sheath 120. Preferably, a lubricating liner 172 is located within the interior of the shaft 120. The shaft reinforcement coil 170 can be mounted within the shaft 120 in contact with the lubricating liner 172, i.e., in a surrounding relationship with the surface of the lubricating liner 172 that covers the interior surface 152 of the shaft 120. A distal flexible tip sheath 174 is secured to the distal end of the outer catheter shaft 120 along the longitudinal axis 176 of the outer catheter 36.

[0132] The distal soft tip sheath 174 may be glued to the rod 120 at end 175 (e.g., Figure 7 as shown), or may cover a portion of the length of the outer surface 173 of the rod 120.

[0133] A distal soft tip sheath 174 extends beyond the coil reinforcement 170 and the lubricous liner 172 at the distal end 160 of the shaft 120 and terminates in a tapered portion 178 having a distal edge 184 and a proximal edge 182 .

[0134] The lubricating liner 172 may be formed of a PTFE material. The distal soft tip sheath 172 may be formed of a very flexible, 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 .

[0135] like Figure 7 and Figure 8A-8B As shown, in one of the preferred embodiments, the sheath 120 has an inner diameter of approximately 0.048" at its inner surface 152, while the rod 120 has an outer diameter of 0.058" at its outer surface 173. The tapered portion 178 of the outer catheter 36 has an inner diameter of ~0.045" at the distal edge 184, while the tapered portion 178 has an outer diameter of ~0.047" at the distal edge 184. The gradient between the outer diameter of the sheath 120 (0.058") and the outer diameter of the tapered body 178 (0.047") defines the tapered outer surface, while the gradient between the inner diameter of the sheath 120 (0.048") and the inner diameter of the tapered body 178 at the distal edge 184 (0.045") defines the tapered inner surface. The thickness of the distal wall 180 of the tapered portion 178 decreases from an interface 182 (between the sheath 120 and the tapered portion 178 ) to an outermost edge 184 of the tapered portion 178 of the distal soft tip sheath 174 .

[0136] Combine Figure 7 and Figure 8A-8B As shown, the outer diameter of the tapered element 104 of the inner catheter is approximately 0.046", which is approximately 0.001" larger than the inner diameter of the distal tip of the outer catheter at the outermost distal edge 184 (0.045"). When the tapered element 104 of the inner catheter is interfered with, 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 end 164 of the outer catheter causes the distal soft tip sheath 174 to stretch at the tapered portion 178 thereof. This configuration provides a nearly seamless transition between the distal ends of the inner catheter 34 and the outer catheter 36, as well as a micro-contouring of the distal end due to the compression of the tapered element 178 of the outer catheter 36 against the distal end of the inner catheter 34. Upon removal of the inner catheter 34, the elastomeric distal tip of the soft tip sheath 174 of the outer catheter 36 allows the tapered portion 178 to return to its original inner diameter (0.045").

[0137] In the disengaged mode of operation, the inner diameter of the wall 180 of the tapered outer end 164 of the outer member 36 is less than the outer diameter of the inner member 34. In the engaged mode of operation, the tapered outer end 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 end 164 of the sheath lumen 120 and the outer diameter of the distal portion of the inner member 34 forms a substantially flush interface transition therebetween.

[0138] Further references Figures 9A-9D , the tapered portion 178 is shown in several embodiments of the expandable tapered design. Figure 9A As shown, the elasticity of the outer catheter 36 at its distal tapered portion 178 is enhanced by an expandable split ring 190 fixed at the tapered portion 178, which allows the distal outer tip 164 to expand (when engaged with the inner catheter 34). The expandable split ring 190 has a slit 192 that allows the ring 190 to expand and contract based on the interference of the inner and outer catheters at their distal ends. This structure provides additional reinforcement to prevent permanent deformation of the tapered portion 178 during removal and delivery of the inner catheter 34 of the stent (or balloon).

[0139] refer to Figure 9BIn an alternative embodiment of the outer catheter 36, the tapered portion 178 can be configured with an expandable end stent 194, which can be made of nickel titanium wire and configured with a distal end 196 and a proximal end 198, with the proximal end 198 having a larger diameter than the distal end 196. Due to its flexibility, the expandable stent 194 expands and contracts as needed and provides additional support to resist permanent deformation of the sheath 174 at the tapered portion 178 during removal and delivery of the stent or balloon member by the inner catheter.

[0140] Another alternative embodiment of the tapered portion 178 at the distal end of the sheath 120 is as follows Figures 9C-9D , wherein the wall 180 of the tapered portion 178 is shaped so that slits 200 extending longitudinally along the length of the tapered portion 178 are dispersed along the periphery of the wall. When the tapered portion 178 engages the distal end of the inner member 34, the slits 200 temporarily widen to encompass the distal tip 162 of the inner catheter 34. This design prevents permanent deformation of the sheath 174 at its tapered portion 178, which could be caused by removal of the inner catheter 34 or during stent / balloon delivery.

[0141] The important "seamless" approach of the present system to the transition between the outer diameter of the outer tip 164 of the sheath 120 (at the tapered portion 178) and the outer diameter of the distal tip 162 of the inner member 34 forms a substantially gradual (smooth) transition therebetween.

[0142] like Figure 2C 、 Figures 10A-10G 、 Figures 11A-11C 、 Figures 12A-12C 、 Figures 13A-13B 、 Figures 14A-14B and Figures 15A-15D As shown, the disclosed system has an interconnection mechanism 220 at the intermediate section 42, which includes a proximal end coupler 130 formed at the proximal end 132 of the sheath 120 of the outer member 36, and a cooperating mechanism 222 (e.g., formed on the outer surface of the inner member 34) formed on the outer surface of the inner member 34. Figures 17A-17B 、 Figure 18B 、 Figures 19A-19B and Figures 20A-20C described in detail in ).

[0143] The disclosed guide catheter extension / pre-dilation system 10 can be operated in an inner / outer catheter engaged mode and an inner / outer catheter disengaged mode, which is achieved by controlling the interconnection mechanism 220. The interconnection mechanism 220 is configured to engage / disengage the inner catheter 34 and the outer catheter 36 (as required by the cardiac procedure) and to prevent undesired forward displacement of the inner member 34 within the outer delivery sheath 120. The engaged mode of operation allows for enhanced “pushability” of the “system as a whole” (the outer catheter 36 is connected and locked to the inner catheter 34), even though the connected push / pull element 134 of the outer member 36 is configured as a low-profile and flexible element (equally flexible or more flexible than the outer tubular sheath 120 of the outer catheter 36).

[0144] When the inner surface 152 of the tubular body 150 of the sheath 120 (at its proximal end 132) engages the outer surface 224 of the cooperating mechanism 222 (on the internal member 34), 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 internal member 34.

[0145] By way of example, a plurality of interconnecting mechanisms are contemplated for use with the disclosed guide catheter extension / pre-dilation system 10. The engagement mechanism is configured for controlled engagement / disengagement between the inner member 34 and the outer member 36, and for preventing forward movement of the inner member 34 relative to the outer delivery sheath 120 beyond a predetermined position.

[0146] For example, Figures 11A-11C As described in detail in the accompanying drawings, the laser cut coupler 130 can be configured with a proximal split (split) ring 240, and a pair of distal rings including an uninterrupted distal ring 242 and a split (split) distal ring 244. The proximal split ring 240, as well as the distal rings 242 and 244, are integrally formed with the coupler base 246. The coupler 130 can be formed from stainless steel or thermoset nickel titanium. The push / pull element 134 of the outer catheter 36 and the mid-displacement coupler (also referred to herein as the proximal coupler) 130 can be made of a memory metal (such as, for example, Nitinol) to prevent deformation during antegrade or retrograde movement of the outer member, as well as to prevent any deformation of the mid-shaft coupler 130 during passage of a stent (or other device) through the mid-shaft portion of the outer catheter 36.

[0147] The split ring 240 is associated with the (eg, funnel-shaped) proximal access opening 211 of the outer catheter 36 (eg, Figure 10A 、 Figure 10D-10E and Figure 11C As shown). The proximal opening ring 240 allows the inlet 211 to expand into the funnel 210 as needed to access / remove the inner catheter 34 as required for the surgical procedure. Figure 10A 、 Figure 10D-10E and Figures 11A-11C As shown, a proximal split ring 240 provides support for the proximal opening 210 proximal to the funnel-shaped shaft 120. The proximal ring 240 strengthens the access opening ("mouth") 211 and prevents damage or permanent deformation of the access opening, thereby supporting the elastic properties of the sheath 120 at the access opening 210. Distal rings 242, 244 form a snap-fit ​​locking mechanism that is separate from the proximal split ring 240 of the funnel. The distal ring 242 does not expand (having a closed circular profile), while the opening of the split ring 244 expands during displacement of the inner catheter 34 relative to the proximal coupler 130 of the outer catheter 36.

[0148] The base 246 of the coupler 130, such as Figure 11B-11C As shown, it can be flat or, preferably, slightly arched (in cross section) to mate with the cooperating distal end 250 of the pusher 134 having a flat or (in cross section) crescent-shaped profile. The pusher 134 can be made of stainless steel or nickel titanium. The distal end 250 of the pusher 134 is welded (glued, adhered or otherwise fixed) to the base member 246 of the coupler 130. The PTFE liner (also shown) Figure 7 As shown) 172 can encapsulate the coupler 130, as Figure 11C shown.

[0149] The sheath 120 is positioned in surrounding relation with the coupler and the PTFE liner 172. Figure 7 The Pebax package at the distal end 160 of the outer catheter 36 (also shown) is similar to the distal soft tip sheath 174 and can be used for the proximal end 132 of the sheath 120. Figure 7 shown) can extend its length to the proximal end of the outer catheter 36.

[0150] like Figures 11A-11C 、 Figures 17A-17C and Figures 18A-18B As shown, Figures 11A-11C The cooperating mechanism 222 shown for the particular embodiment also includes a mid-bar locking ring 252 (eg, Figures 17B-17C and Figure 18B shown).

[0151] like Figures 12A-12C Another embodiment of the proximal end inlet structure of the outer catheter is shown in FIG. Figure 11A – Figure 11C Similar to the one shown, with some modifications, including:

[0152] (a) additional thickness and additional material around the base 246 of the coupler 130;

[0153] (b) improved surface treatment (e.g. sandblasting) to improve adhesion of the polymer encapsulation; and

[0154] (c) Encapsulation with a rigid polymer (e.g., nylon) provides additional support to the funnel to prevent damage that could obstruct stent passage.

[0155] Another embodiment of the coupler 130 at the proximal inlet 210 (e.g. Figures 13A-13B ) features split rings (ribs) 256 that reinforce the inlet port 210. A snap-fit ​​lock 260 is represented by at least two split rings 262 at the distal end of the coupler 130. The coupler 130, as shown in Figures 13A-13B The laser cut coupler is preferably formed from stainless steel or heat set nickel titanium.

[0156] The hypodermic tube pusher / puller 134 may be flattened at its distal end 250 and welded to the base 246 of the coupler 130. A PTFE liner 172 extends beneath the coupler 130, and a Pebax encapsulation 174 encapsulates the coupler 130 with the pusher 134 secured thereto. A catheter shaft coil reinforcement structure 170 extends along the shaft 120 of the outer catheter 36 from its distal end to its proximal end. A snap fit lock 260 is provided with the outer catheter 36. Figures 17A-17C 18B cooperates with the ring embodiment of the cooperating mechanism 222. In some embodiments, the package 174 and / or the pusher / puller 134 can be painted different colors, such as Figure 11A 1 and 2. As shown, the outer member pusher / puller 134 is distinguished from the other elements of the disclosed arrangement for the surgeon's convenience and safety of the procedure.

[0157] Additional modifications to coupler 130 are in Figures 14A-14B 130 has separate rings 266, 268 welded to the distal end 250 of the pusher 134. As shown, the locking mechanism 260 is formed by an uninterrupted distal ring 266 and an intermediate split ring 268, each of which is welded to the pusher 134. A proximal beveled split ring 270 is also welded to the pusher 134. This design provides increased flexibility in the size and configuration of each ring 266, 268, and 270, and supports the formation of different funnel shapes / sizes, rather than being limited to a single diameter laser-cut coupler.

[0158] Figures 15A-15B Another modification of the proximal coupler 130 is depicted, featuring a funnel fenestration that increases the contrast agent infusion flow rate by providing an additional open cross-sectional path for fluid flow. Figures 15A-15BAs shown, circular openings 272 are formed in the sheath 120. The openings 272 are positioned in a predetermined pattern so as not to interfere with the proximal and distal split rings 274, 276, 278 of the snap-fit ​​locking structure 280. Figure 15C-15D As shown, the coupler 130 is formed with a triangular shaped opening 282 formed in the sheath 120 that does not interfere with the proximal and distal rings 274 , 278 , 276 of the snap-fit ​​lock 280 .

[0159] Although in 15A- Figure 15D Only circular and triangular openings 272, 282, respectively, are shown in FIG, but other configurations of cutouts in the plastic package to allow infusion of contrast fluid through the cutouts are also contemplated in the disclosed structures.

[0160] refer to Figure 16A 、 Figure 16B and Figure 16C , presents another embodiment of the proximal end of the outer catheter 36 that is specifically designed as a potential solution to prevent unwanted embolic situations when air is inadvertently introduced with the fluid injected between the inner and outer catheters 34, 36. To prevent this, a flush lumen 290 is built into the pusher 134 through a flat hypodermic tube. The Luer hub is coupled to the proximal end of the hypodermic tube (pusher 134), as shown. Figure 16C As shown, the surgeon can inject fluid between the inner and outer catheters through the hypodermic tube 134. When the fluid enters the outer catheter lumen 292 through the channel 290 in the hypodermic tube 134, air bubbles are prevented from entering between the inner and outer catheters.

[0161] In addition, refer to Figures 17A-17C , Figure 11A-Figure 1 1E, Figures 12A-12C 、 Figures 13A-13B 、 Figures 14A-14B and Figures 15A-15D , an interconnection unit 220 between the proximal couplers 130 is presented, comprising a cooperating member 222 in the form of an annular ring 252 (also referred to herein as an intermediate locking ring) formed on the outer surface 224 of the inner catheter 34. The profile of the stainless steel ring 252 has a completely circular surface that allows for minimal reversible engagement / disengagement with the desired split ring feature of the outer catheter coupler 130. Figure 17C The ring 252 shown has a rounded profile on the outer surface 302 for a smooth locking / unlocking action. The inner surface 304 of the ring 252 is also a smooth structure that engages the outer surface 224 of the inner conduit 34.

[0162] Figure 17A The inner conduit 34 is depicted in a separated configuration relative to the outer conduit 36 ​​. Figure 17B1 shows the locked engagement configuration when the inner catheter 34 is received and locked within the opening 210 at the proximal end of the sheath 120, such that the ring 252 engages in the snap-fit ​​lock 306 formed by the distal uninterrupted ring 308 and the middle split ring 310. When in place, the proximal beveled split ring 312 surrounds the inner catheter 34 and the ring 252 locks in the snap-fit ​​lock 306, thereby engaging the inner and outer catheters for surgical manipulation as desired.

[0163] During the longitudinal movement of the inner catheter 34 within the outer catheter 36, as the ring 252 passes through the proximal bevel split ring 312 and the intermediate split ring 310, the ring arms of these rings expand from their original positions to create sufficient space for the ring 252 to pass through. When in place, that is, the ring 252 is received between the rings 308 and 310, the ring arms of the bevel split ring 312 and the split ring 310 return to their original closed positions. The ring 252, which is caught between the rings 308 and 310, is snap-fit ​​locked between the rings 308 and 310, thereby preventing relative displacement of the inner and outer catheters.

[0164] Reference Figures 18A-18B , detailed description Figures 17A-17C The section (recess) 316 of the sheath 120 showing the outer catheter 36 is not reinforced by the coil 170 and deflects when the mid-shaft locking ring 252 is inserted between the uninterrupted distal ring 308 and the mid-split ring 310 of the snap-fit ​​lock 306. The deflected portion 316 of the sheath 120 between the rings 308 and 310 provides additional retention force to keep the inner catheter 34 and the outer catheter 36 in locked engagement.

[0165] The stainless steel circular ring 252 can be attached to the outer surface 224 of the inner catheter shaft 34 by adhesive. The locking ring geometry (all-round surface) allows for smooth, reversible engagement / disengagement with the laser-cut features of the outer catheter coupler 130. The distal ring 308 of the snap-fit ​​lock 306 prevents further distal movement of the inner catheter 34, while the mid-shaft split ring 310 opens and provides a tactile snap when in contact with the mid-shaft locking ring 252. The proximal bevel split ring 312 allows the funnel 211 to open to an inner diameter larger than the inner diameter of the rest of the shaft 120. The proximal bevel split ring 312 also allows for smooth passage of the mid-shaft locking ring 252.

[0166] The interference between the unreinforced rod recess 316 and the mid-rod locking ring 252 holds the inner tube 34 on the outer tube 36 until the user is ready to remove the inner tube 34 from the outer tube 36, thereby disengaging the snap-fit ​​lock therebetween. The force required to release the locking mechanism can be tailored from 0.1 to 2.0 pounds.

[0167] refer to Figures 19A-19C, shows another alternative embodiment of the middle lever lock, which includes a square ring 320 (formed from metal or polymer material). Figures 17A-17C and Figure 18B The ring 252 shown is different in that Figure 19C As shown, the ring 320 has a square cross-section 321. The square ring 320 is secured to the outer surface 224 of the inner conduit 34 by a hot melt Pebax encapsulation 322. Alternatively, it can be glued to the inner conduit outer surface 224. Figure 19B As shown, when the inner catheter is in the locked position, the square ring 320 snaps into the snap-fit ​​lock 324 formed by the uninterrupted ring 326 and the split ring 328 , with the package 322 in contact with the inner surface 152 of the sheath 120 and the ring 320 located between the rings 326 and 328 .

[0168] In another alternative embodiment, Figures 20A-20C As shown, the middle rod locking mechanism 220 and the cooperating member 222 form a cage structure 330 having two nickel titanium rings 332, 334 connected together by a plurality (eg, four) nickel titanium formed wires 336. Figure 20A As shown, the cage 330 is secured to the outer surface 224 of the inner conduit 34 by gluing or by hot-melting a Pebax encapsulation 338. Each wire 336 has an arcuate extension 340 that is not encapsulated, as shown in FIG. Figure 20A and Figure 20B shown.

[0169] like Figure 20B As shown, for the locked configuration, the cage structure 330 snaps into the coupler 130 of the outer conduit. The unencapsulated arcuate portion 340 of each wire 336 extends outside the enclosure 338 and away from the wire 336 of the cage 330. 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 conduit 34 and the outer conduit 36 ​​engage.

[0170] Further references Figure 21 , the proximal coupler 130 of the outer catheter 36 may include two locking grooves 350 , 352 formed by rings 354 and 356 connected together by a connecting element 358 .

[0171] refer to Figure 17A – Figure 17C 、 Figure 18A – Figure 18B 、 Figure 19A – Figure 19B 、 Figure 20A – Figure 20C ,as well as Figure 10A – Figure 10G 、 Figure 11A – Figure 11C 、 Figure 12A – Figure 12B 、 Figure 13A – Figure 13B 、 Figure 14A – Figure 14B 、 Figure 15A – Figure 15D and Figure 21 As the surgeon linearly displaces the inner member 34 within the internal channel 122 of the proximal coupler 130, the snap-fit ​​ring 252, 320, or cage 330 enters the channel 122 between the arms of the proximal rings 240, 312, which flex outward to allow the inner catheter 34 to move forward (toward the distal tip 162). As the snap-fit ​​ring 252, 320, or cage 330 further passes through the snap-fit ​​lock's mid-split rings 244, 262, 268, 310, 328, the arms of the beveled proximal ring return to their original position, but the arms of the mid-split ring flex outward to allow the rings 252, 320 of the cage 330 to reach a position between the distal uninterrupted ring and the mid-split ring. After the rings / cages 252, 320, 330 snap fit between the rings of the snap-fit ​​locking mechanism, the arms of the mid-split ring return to their original position.

[0172] To separate the inner member 34 from the outer member 36, the surgeon pulls the inner member 34 out of the internal passageway of the proximal coupler 130. During the removal of the snap-fit ​​rings / cages 252, 320, 330 from the passageway, the pulling action causes the arms of the central split ring to flex outward to allow the snap-fit ​​rings / cages 252, 320, 330 to pass therebetween, thereby releasing the inner conduit 34 from the proximal coupler 130 of the outer conduit 36.

[0173] return Figure 3D , the inflation lumen distal rod 66 at the intermediate section 42 of the 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 that connects to the cooperating mechanisms 222 of the interconnecting cells 220 of the inner member 34. An RX (rapid exchange) port 94 for passing the guide wire 12 can be formed through the wall of the braided reinforced inflation lumen distal rod 66.

[0174] The braided reinforcement structure 260 can be configured with a metal pattern or wire within the braided reinforced inflation lumen distal rod 66 to prevent kinking, which will provide longitudinal stiffness to the rod 66. The metal braid 260 can be embedded in the braided reinforced rod 66 to increase its flexibility required to retract the inner member 34 relative to the outer delivery sheath 120 during surgery.

[0175] A flat wire helical coil (e.g., made of a shape memory alloy such as Nitinol) having a wire thickness of approximately 1 mil to 3 mils can be embedded in the braid 260. The coil can be formed with a very thin coating of plastic placed on its inner and outer surfaces, which helps reduce the wall thickness of the inflation lumen distal rod 66 to less than 7 mils, and preferably to approximately 5 mils.

[0176] The principle of reinforcing or forming a tubular member by a catheter shaft coil reinforcement 170 in the form of a flat wire helical coil 262 can be applied in a guide catheter extension / pre-dilation system 10 to an outer delivery sheath 120 (e.g., Figure 7 、 Figure 8B 、 Figures 9A-9D 、 Figure 10A 、 Figure 11C 、 Figure 12B-12C 、 Figures 13A-13B 、 Figure 14B 、 Figures 15A-15C 、 Figures 16A-16B 、 Figures 17A-17B 、 Figures 18A-18B 、 Figure 19B 、 Figure 20B and Figure 21 ) as shown, and microcatheter 46 (as Figure 2A-2B 、 Figure 5A , Figure 22 and Figures 24A-24B ). In the outer delivery sheath 120 and / or microcatheter 46, such flat wire helical coils may be embedded at predetermined locations along the length of their walls, such as at the proximal and / or distal ends.

[0177] Alternatively, the entire length of the outer delivery sheath 120 and / or microcatheter 46 can be formed from a flat wire helical coil. The pitch between the coils can be adjusted to provide a gradient of flexibility that increases along the length of the tubular member (sheath 120 and / or microcatheter 46) toward its distal end to facilitate atraumatic operation.

[0178] refer to Figures 22A-22B and Figures 23A-23C Instead of using a standard OTW guidewire lumen, a single-track Rapid Exchange (RX) design of the inner catheter 34' can be implemented to allow the use of a short guidewire. Figure 22A and Figure 22B In the embodiment shown, which represents an isometric view and a side view taken along line AA of a coil-reinforced inner member rod 400, the distal section 40' of the inner member 34' includes a tapered element 402 attached to the outer surface 224 of the inner member 34. The outer rod 400 of the inner member 34' is a coil reinforced with a coil reinforcement structure 404 that extends from a distal tip 406 to a distal end. Figure 2A – Figure 2C and Figure 3C – Figure 3D RX inlet 94 is shown. Distal tip 406 is a tapered, flexible tip that, along with tapered element 402, engages the inner surface of outer catheter 36 when inner catheter 34' is installed in outer catheter 36 as desired for the surgical procedure.

[0179] The distal section 40' includes a concentric guidewire lumen 408 that communicates with the RX access port proximal to the inner catheter 34 (eg, Figure 2A-2C and Figure 3C-3D shown).

[0180] like Figures 23A-23C As shown, the proximal end 412 of the monorail microcatheter embodiment is Figures 22A-22B The use of a cut hypodermic tube pusher 414 is shown. The proximal end 412 of the coil-reinforced inner member shaft 416 and the hypodermic tube pusher 414 are enclosed in a proximal outer sheath 418, which is a tubular member extending from (and including) the proximal end 412 of the coil-reinforced inner member shaft 416 and the hypodermic tube pusher 414. Figures 22A-22B A coil-reinforced inner member rod 416 (serving as the guidewire lumen 408) and a hypodermic tube pusher 414 are shown extending along the proximal end 412 of the monorail microcatheter embodiment of the inner member 34'.

[0181] Figures 23A-23B The depicted embodiment features an RX guidewire "notch" terminal / portal 420, which is created by piercing the proximal outer sheath 418. Subsequently, the coil-reinforced inner member rod 416 is inserted into the proximal outer sheath tube 418 through the RX port "notch" 420. The cut hypodermic tubing 415 is further inserted into the proximal sheath tube 418 through its lumen 422, and the polymers of the coil-reinforced inner member rod 416 and proximal sheath tube 418 are fused together to connect the inner member shaft 416 and the pusher 414, thereby forming the proximal end 412 of the monorail microcatheter inner member 34'.

[0182] For the convenience of the surgeon, the push / pull element 134 of the outer catheter 36 may be colored (colored coated), such as Figure 11A As shown, the push / pull element 414 may be provided with a distinctive color to distinguish it from other elements of the system, such as the push / pull element of the inner catheter 34, and from the typically gray or silver color of a coronary guidewire used for a delivery device or for a stent delivery system. Alternatively, the proximal outer sheath 418 of the push / pull element 414 may be colored to distinguish it from the colors of the other elements of the disclosed system.

[0183] Further references Figures 24A-24B, represents an additional coil-reinforced balloon catheter embodiment 500 of the inner catheter, which combines the reinforcing rod characteristics of the microcatheter 46 with the rod characteristics of the dilation balloon 44, and has the following properties:

[0184] a. The coil-reinforced rod 502 provides additional kink resistance and pushability while still maintaining flexibility for navigating tortuous vasculature; and

[0185] b. The longer distal end 504 of the construct contains a low-profile, tapered soft tip to facilitate passage through narrow and tight lesions.

[0186] like Figures 24A-24B As shown, the distal section 504 of the structure 500 includes an inner member rod 500 reinforced with a helical reinforcement structure 506 that extends the length of the inner member rod 500. A distal tapered element 508 is positioned on the inner member rod 500 and extends between ends 510 and 512 in surrounding relation to the inner member rod 500. The distal tapered flexible tip 514 can be in the form of a microcatheter 46 positioned at the end of the coil-reinforced shaft 500.

[0187] Similar to Figures 22A-22B , the balloon member 44 is located on the inner member shaft 500, and the radiopaque markers 264 and 266 are located 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 tapered element 178 of the outer member sheath 120. At the distal end 518, the balloon member 44 tightly surrounds the shaft 500.

[0188] Back to Figure 1-24B In operation, to perform a cardiac procedure, particularly a pre-dilatation procedure, the proximal end of the coronary guidewire 12 enters the RX port 94 formed in the inflation lumen distal rod 66, extends through the interior passageway (GW lumen 96) of the inner member 34 toward the distal end 52 of the microcatheter 46, and extends beyond the distal end 52 of the microcatheter 46. Thereafter, the guide catheter 14 is advanced into the vessel 16 of interest.

[0189] Subsequently, the outer delivery sheath 120 of the outer member 36, with the inner member 34 locked therein, is first placed in the interior channel 48 of the guide catheter 14 together with the microcatheter 46, and the inner and outer members 34, 36 are integrally advanced within the guide catheter 14 toward the treatment site 22 as a unit. The outer member sheath 120 and the inner member 34 can be integrally displaced by pushing the outer member pusher 134. This action causes the microcatheter 46 of the inner member 34 to slide along the GW 12 together with the outer member 36 until they extend beyond the distal end 50 of the guide catheter 14 and reach the lesion site 92. At this step of the procedure, the balloon member 44 is in its deflated configuration.

[0190] A guide wire 12 extending beyond the distal end 50 of the guide catheter 14 serves as a guide, and the microcatheter 46 (with the deflated balloon 44 attached to the distal tip 162 ) is slid along the guide wire 12 toward the treatment site 26 .

[0191] The balloon member 44 (positioned at the treatment site 22 ) is then inflated by a balloon inflation system 62 connected to the inflation hub 56 via an inflation lumen formed by an inflation lumen distal rod 66 and an inflation lumen hypodermic tube 64 to compress the plaque and widen the blood passage within the blood vessel 16 .

[0192] Subsequently, once the lesion has expanded, the balloon 44 is deflated and the outer delivery sheath 120 can be advanced through the lesion 22 with the inner member 34 as an integral unit (in an engaged operating mode), and the inner member can then be detached (unlocked) from the outer delivery sheath 120 and removed from the sheath 120.

[0193] Alternatively, the inner member 34 may be detached and withdrawn from the sheath 120 directly after dilation of the lesion, while the outer member 36 is advanced through the lesion 22 .

[0194] The sheath 120 may be left in place adjacent the treatment site (immediately following dilation of the lesion).

[0195] After pulling the inner member 34, the stent can be delivered to the site 22. The stent in its closed configuration can be introduced into the blood vessel 16 within the sheath 120. When in place, the stent support balloon (not shown) can be inflated to open the stent. Subsequently, the outer delivery sheath 120 is removed, leaving the opened stent in the blood vessel 16.

[0196] While the present invention has been described in conjunction with specific forms and embodiments thereof, it should be understood that various modifications in addition to those described above may be employed without departing from the spirit or scope of the invention as defined in the appended claims. For example, functionally equivalent elements may be substituted for those specifically shown and described, certain features may be used independently of other features, and in some cases, the specific positions of elements, steps, or processes may be reversed or inserted, all without departing from the spirit or scope of the invention as defined in the appended claims.

Claims

1. An intravascular delivery system having a proximal segment, a distal segment, and an intermediate segment located between the proximal segment and the distal segment, and configured to be controllably displaceable within a blood vessel of interest, the intravascular delivery system comprising: an outer member formed of 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 section and the distal section and configured with a tapered outer tip, wherein the proximal end of the outer delivery sheath of the outer member is configured with a mouth, wherein the mouth includes a funnel-shaped access opening; wherein 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 fashion between a distal edge and a proximal edge of the tapered outer tip, wherein the wall has an inner diameter and an outer diameter, and wherein the inner and outer diameters of the wall gradually decrease in a direction from the proximal edge to the distal edge of the tapered outer tip; an inner member having an elongated body defining an internal passageway extending along a longitudinal axis thereof, the inner member extending internally along the sheath lumen of the outer member in a controlled relationship with the outer delivery sheath, wherein the elongated body of the inner member has a proximal end and a tapered distal portion having an outer diameter and configured with a tapered delivery catheter having an elongated body of a predetermined length, the tapered delivery catheter being displaceable beyond the distal end of the outer delivery sheath, wherein the wall of the tapered outer end of the outer member is configured to engage the distal portion of the inner member, and wherein at a junction between the wall of the tapered outer end of the outer member and the distal portion of the inner member, the inner diameter of the wall of the tapered outer end of the outer member is less than the outer diameter of the distal portion of the inner member; and an interconnection mechanism controllably actuated to operate the inner member and the outer member in an engaged mode of operation or a disengaged mode of operation, wherein the interconnection mechanism comprises a proximal coupler formed at a proximal end of an outer delivery sheath of the outer member, and a cooperating mechanism formed on an outer surface of the inner member, wherein the proximal coupler comprises a proximal split ring and a pair of distal rings, the pair of distal rings comprising a distal uninterrupted ring and a distal split ring, wherein the proximal split ring is associated with the funnel-shaped mouth, wherein the distal uninterrupted ring and the distal split ring form a snap-fit ​​locking mechanism that is disengaged from the proximal split ring; wherein, in the engaged mode of operation, the inner and outer members are engaged for controlled joint displacement along a guide line, and when engaged, the inner member is prevented from independent displacement relative to the outer member, and Wherein, in the separation operation mode, the inner member and the outer member are separated for retracting the inner member from the outer member.

2. The intravascular delivery system according to claim 1, in, The tapered distal portion of the inner member engages at its outer surface the inner surface of the tapered outer tip, wherein said tapered outer end of said outer member comprises an elastomeric material, wherein, in the separated mode of operation, the inner diameter of the wall of the tapered outer end of the outer member is smaller than the outer diameter of the inner member, and Wherein, in the engaged operating mode, the tapered outer end of the outer member and the inner member interact so that the dimensional transition between the inner diameter of the wall of the tapered outer end and the outer diameter of the inner member forms a substantially flush engaged transition between the inner diameter of the wall of the tapered outer end and the outer diameter of the inner member.

3. The intravascular delivery system according to claim 1, wherein: The outer delivery sheath is reinforced along its length, wherein the outer member further comprises a distal soft tip encapsulation material, the distal soft tip encapsulation material encapsulating the outer delivery sheath of the outer member at the distal end of the outer member, wherein the distal soft tip encapsulation material is a flexible low hardness elastomeric material having a gradient hardness value that increases from the distal end to the proximal end of the outer delivery sheath.

4. The intravascular delivery system according to claim 3, wherein: The outer member also includes a distal lubricious lining sandwiched between an outer surface of the outer delivery sheath and an inner surface of the distal soft tip encapsulation material.

5. The intravascular delivery system according to claim 1, wherein: The tapered delivery catheter is a tapered delivery microcatheter, further comprising: a balloon member attached to the tapered distal portion of the inner member proximate the tapered delivery microcatheter; and An inflation lumen extends within the inner member between the proximal section and the balloon member at the distal section to provide a fluid pathway between an external balloon inflation system and the balloon member.

6. The intravascular delivery system according to claim 5, wherein: The balloon member has a proximal portion having a proximal diameter that exceeds a distal diameter at a distal portion of the balloon member.

7. The intravascular delivery system according to claim 5, wherein: The balloon member assumes an inflated configuration and a deflated configuration, wherein in the deflated configuration the balloon member is displaced within a blood vessel, and wherein the balloon member controllably transitions to the inflated configuration after the balloon member is positioned at least in alignment with a treatment site for a pre-dilation procedure.

8. The intravascular delivery system according to claim 5, wherein: The elongated body of the inner member and the microcatheter are reinforced along their lengths by coils.

9. The intravascular delivery system according to 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 located at the distal end of the outer delivery sheath and the proximal end of the outer delivery sheath, and wherein at the proximal end of the outer delivery sheath, the outer delivery sheath is configured with an entry opening having a second predetermined circumference, the second predetermined circumference of the entry opening exceeding the first predetermined circumference of the tubular body of the outer delivery sheath.

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

11. The intravascular delivery system according to claim 2, further comprising: An outer member pusher is configured with a flat portion at a distal end and is secured to the proximal end of the outer delivery sheath of the outer member, wherein the outer member pusher is configured with a channel extending along its length in fluid communication with the sheath lumen.

12. The intravascular delivery system according to claim 11, wherein: The outer delivery sheath of the outer member is a flexible outer delivery sheath having a first flexibility along its length, wherein the outer member pusher is a flexible member having a second flexibility along its length, the second flexibility being substantially equal to or exceeding the first flexibility.

13. The intravascular delivery system according to claim 1, wherein: The cooperating mechanism includes a member selected from the group consisting of a mid-bar locking ring, a square ring, and a snap cage, the cooperating mechanism being secured to an outer surface of the elongated body of the inner member.

14. The intravascular delivery system according to claim 13, wherein: The cooperating mechanism is secured to the outer surface of the inner component in surrounding relation thereto.

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

16. The intravascular delivery system according to claim 5, wherein: The microcatheter is formed of a flexible material having varying flexibility along its length, wherein the flexibility of the microcatheter increases toward its distal end.

17. The intravascular delivery system according to claim 16, wherein: The microcatheter includes a flat wire helical coil extending along a predetermined length of the microcatheter, and wherein a pitch of the flat wire helical coil varies along the length of the microcatheter to increase flexibility of the microcatheter toward the distal end thereof.

18. The intravascular delivery system of claim 1 further comprising a flat wire helical coil member forming at least a portion of a corresponding wall of a member selected from the group consisting of: the outer delivery sheath of the outer member, the delivery catheter, the elongated body of the inner member, and combinations thereof, wherein the flat wire helical coil is formed of a shape memory alloy comprising nitinol or a radiopaque material.

19. The intravascular delivery system according to claim 1, wherein: The tapered delivery catheter is a microcatheter having a longitudinally extending lumen formed therein for sliding along the guide wire, and further comprising: an inner member pusher coupled at its distal end to the proximal end of the inner member; and an outer member pusher coupled at a distal end thereof to the proximal end of the elongated body of the outer member; The outer member pusher is colored, the color of the colored coating being different from the color of the guide wire and different from the color of the inner member and the inner member pusher.

20. The intravascular delivery system according to claim 1, wherein The cooperating mechanism includes a ring.

21. The intravascular delivery system according to claim 1, wherein: The distal uninterrupted ring does not expand, while the opening of the distal split ring expands during displacement of the inner member relative to the proximal coupler of the outer delivery sheath.

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

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