Intravascular delivery systems and methods for percutaneous coronary interventional therapy including perfusion

Abstract

A guide catheter extension / pre-expansion system of the present disclosure includes: an outer delivery sheath; an inner member extending within the sheath; and an engaging / disengaging mechanism for engaging / disengaging the inner member to / from 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 proximate the microcatheter. The outer delivery sheath and the inner member are modified for different engagement / disengagement mechanism operations. The external delivery sheath includes one or more apertures configured to reduce or eliminate the risk of myocardial ischemia.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Application No. 18 / 046,699, filed on October 14, 2022, the entire content of which is incorporated herein by reference. U.S. Patent Application No. 16 / 132,878 and U.S. Patent Application No. 15 / 899,603 are incorporated herein by reference. Technical field

[0003] The present disclosure relates to minimally invasive devices for the treatment of, such as, coronary arteries within the human vasculature, and more particularly to a delivery system for percutaneous coronary intervention that is specifically adapted for intravascular balloon angioplasty and coronary stent delivery, where intravascular balloon angioplasty and coronary stent delivery are enhanced by pre - dilation guide catheter extension capabilities.

[0004] The present disclosure also relates to a medical device that is designed for: non - invasive, convenient, and rapid delivery of various interventional devices, such as pre - dilation balloons or stents; and, replacement of catheters within the coronary arteries (or other blood vessels) of a patient to facilitate percutaneous revascularization.

[0005] The present disclosure further relates to an intravascular delivery system having a micro - tapered soft distal end that enables the interventional devices of the present disclosure to have exceptional delivery capabilities superior to conventional balloon angioplasty catheters and its actual non - traumatic crossing capabilities at the site of treating lesions.

[0006] The present disclosure also relates to an intravascular guide catheter extension / pre - dilation system using an inner member (interventional device delivery catheter subsystem) that is positioned at a predetermined location inside an outer member (outer delivery catheter subsystem), where the inner member is formed with a distal coil - reinforced tapered portion that butts against a slightly tapered distal end of the outer member. The distal coil - reinforced tapered portion of the inner member and the slightly tapered distal end of the outer member are sized to form a micro - profile and a substantially "seamless" transition at the interface between the distal ends of the outer member (outer catheter) and the inner member (inner catheter), at the transition point where the distal portion of the inner catheter engages or enters the outer member. This configuration is highly beneficial for the inner member and the outer member to pass through diseased blood vessels as a single unit non - invasively and smoothly.

[0007] Additionally, the present disclosure relates to an intravascular guiding catheter extension / pre - dilation system configured with an outer catheter (member) and an inner catheter (member), the inner catheter (member) being capable of displacing within and along the outer catheter, wherein the distal tapered soft tip of the outer catheter is formed as an inflatable flexible low - hardness elastomeric member, and in the reduced configuration of the elastomeric member, the inner diameter of the elastomeric member is smaller than the outer diameter of the distal portion of the inner catheter at the engagement region with the outer catheter. This arrangement enables a reversible elastic engagement between the outer catheter and the inner catheter at their distal ends, which ensures that when the inner catheter has been removed from the outer catheter, the inflated distal end of the outer catheter returns to its reduced outer diameter, and when advancing the system around a bend in a blood vessel, reduces (or eliminates) the "fish - mouth" defect at the distal junction of the outer and inner members.

[0008] Further, the present disclosure relates to an intravascular guiding catheter extension / pre - dilation system configured with an outer catheter and an inner catheter capable of displacing relative to each other, wherein the proximal end of the outer catheter has an inlet configuration that provides enhanced reinforcement, an enhanced central rod support inlet, prevention of stent embolization, increased flexibility, and improved flow rate of contrast agent infusion fluid.

[0009] Moreover, the present disclosure relates to an intravascular guiding catheter extension / pre - dilation system designed with a central rod interconnecting (locking) mechanism, the central rod interconnecting (locking) mechanism being actuated / de - actuated by a physician to (1) controllably engage the inner and outer members for integral movement along a guide wire within the guiding catheter, or (2) disengage the inner catheter and the outer catheter as needed for an intravascular procedure to retract the inner catheter from the outer member (catheter). The inner member may carry an interventional device (such as a pre - dilation balloon member or a stent) attached to its tapered coil - reinforced distal end, and the locking mechanism provides a smooth, reversible engagement / disengagement procedure. This reversible locking of the central rod also prevents any forward movement of the inner member relative to the outer member during system advancement or withdrawal and ensures that the position of the distal "seamless" transition between the inner and outer catheters remains substantially axially fixed in place during movement of the system of the present disclosure.

[0010] Additionally, the present disclosure relates to an intravascular guiding catheter extension / pre - dilation system configured at its distal end with a tapered coil - reinforced rod for mounting and carrying a balloon member thereon and providing a "seamless" entry of the balloon member integrated with the coil - reinforced delivery sheath of the outer catheter and smooth delivery ability to a desired treatment site.

[0011] The present disclosure further relates to an intravascular guiding catheter extension / pre - dilation system featuring a monorail microcatheter embodiment having a rapid exchange (RX) feature for applications with a short guidewire, wherein the distal tapered soft end of the inner catheter is configured with a coil - enhanced microcatheter that provides additional kink resistance and "pushability" while still maintaining flexibility for navigating tortuous vasculature.

[0012] Additionally, the present disclosure relates to an intravascular guiding catheter having an outer catheter formed by a sheath defining one or more side holes that permit distal perfusion. Background Art

[0013] Coronary obstructive disease or other diseases in the peripheral vascular system are typically treated by balloon angioplasty and / or stent placement. Advancing an intravascular vascular reconstruction device, such as a balloon delivery system or a stent delivery system, to the treatment site can be challenging for a physician when the blood vessel is curved and / or calcified.

[0014] A coronary stent is a tubular device placed in the coronary artery that supplies blood to the heart to keep the artery open, for treating coronary heart disease, and is used in a procedure often referred to as percutaneous coronary intervention (PCI). Stents help improve coronary blood flow, relieve chest pain, and have been shown to increase survival in the event of acute myocardial infarction.

[0015] Treating an occluded coronary artery with a stent generally follows the same steps as other angioplasties, but there are important differences. A compressed stent mounted on a balloon significantly reduces the flexibility of the balloon and impairs the smooth advancement of the balloon through the coronary artery. This can make it difficult or impossible to deliver the stent to the treatment site and there may be a risk of an undeployed stent detaching from its delivery balloon.

[0016] Intravascular imaging can be used to evaluate the thickness and stiffness (calcification) of a lesion, which will affect stent deliverability. Cardiologists use this information to decide whether to treat a lesion with a stent and, if so, which type and size of stent to use. Both bare - metal stents and drug - eluting stents are most commonly sold as a unit, where the stent is attached to the outside of a balloon catheter in its folded (pre - inflated) form.

[0017] A physician can perform "direct stent implantation", where the stent is advanced through the blood vessel to the lesion and inflated. However, it is common to pre - dilate the occlusion before delivering the stent to facilitate stent delivery in more challenging lesions.

[0018] Pre - dilation is accomplished by passing a conventional balloon catheter through the lesion and inflating the lesion to increase its diameter. A balloon catheter is a "soft" catheter that has an inflatable balloon at its distal end, and the inflatable balloon is used during catheter insertion procedures to expand a narrow opening or passageway in the body. After pre - dilation, the pre - dilation balloon is removed, and a stent catheter is passed through the blood vessel to the lesion and inflated. The stent catheter remains as a permanent implant to "stent" open the blood vessel at the lesion site.

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

[0020] Vascular reconstruction devices typically use a guiding (or guide) catheter to deliver such devices to the site of treatment. Using a guiding catheter alone to "support" the advancement of a vascular reconstruction device into the coronary artery can be limited and challenging, especially when using a radial access guiding catheter to place a stent.

[0021] To facilitate the delivery of vascular reconstruction devices to the site of interest, guiding catheter extension systems have been designed and used during cardiac procedures.

[0022] For example, a guiding extension system such as "GuidelinerTM" is manufactured by Teleflex. This guiding extension system is described in U.S. Patent #8,292,850 written by Root et al. Root et al. (U.S. Patent #8,292,850) describe a coaxial guiding catheter that passes through the lumen of a guiding catheter and is used with interventional cardiology devices that can be inserted into a branch artery branching off the aorta.

[0023] The Root coaxial guiding catheter extends through the lumen of the guiding catheter and beyond the distal end of the guiding catheter and is inserted into the branch artery. Root uses a guiding extension supported by a tapered inner catheter. The purpose of the inner catheter is to provide an atraumatic tip to avoid vascular injury while advancing the guiding extension into the proximal portion of the coronary artery blood vessel to provide additional "support" for the delivery of a stent or balloon.

[0024] Another guiding extension system, such as "GuidezillaTM", is designed and manufactured by Boston Scientific. This guiding extension system is described in U.S. Patent #9,764,118 written by Anderson et al. Anderson's guiding extension system uses a pusher member having a proximal portion with a proximal stiffness, a distal portion with a distal stiffness different from the proximal stiffness, and a transition portion providing a smooth transition between the proximal and distal portions. A distal tubular member is attached to the pusher member and has an outer diameter greater than that of the pusher member.

[0025] U.S. Patent Application Publication #2017 / 0028178 written by Ho describes a guiding extension system using a slotted catheter that is extensible when inserting a balloon or stent delivery system. Ho's guiding extension also uses a rigid pusher rod to assist in delivering the guiding extension to the treatment site.

[0026] The systems "GuidelinerTM" and "GuidezillaTM" and Ho's system support the concept of advancing a guiding extension system through a guiding catheter and partially down the coronary artery in order to achieve additional "support" to deliver a balloon dilation catheter and / or a stent delivery catheter to the site of intended treatment.

[0027] The function of these guiding extensions is to allow closer access to the lesion to provide additional support when crossing the lesion to be treated with an interventional device. However, despite the additional support, due to fibrosis, calcification, previous stent struts within the lumen, and / or the angle at the lesion site, the lesions to be treated with a pre-dilation balloon catheter or a stent delivery system are still difficult or nearly impossible to cross.

[0028] One of the limitations of currently used guiding extension devices is that these guiding extension devices use relatively blunt and large-caliber cylindrical distal ends. The relatively high-profile distal edge limits the delivery ability of the guiding extension in many cases and only allows advancement to the proximal or middle portion of the coronary artery to be treated. Even after balloon pre-dilation of the lesion, if at all, it is rarely possible to deliver the guiding extension to the actual lesion to be treated with angioplasty or a stent. These "blunt-tipped" tubular guiding extension devices may fail relatively frequently and may cause serious anatomical complications. Published data demonstrate that "blunt-tipped" tubular guiding extension systems may result in a 20% failure rate in cases and cause severe coronary artery dissection in approximately 3% of cases.

[0029] U.S. Patent Application Publication #2011 / 0301502, written by Gill, describes a catheter with a longitudinally extending member, thereby allowing the positioning device to have a diameter smaller than that of the stent delivery system. However, the Gill device does not contemplate that the inner catheter allows for easy and atraumatic passage through the lesion to be treated. The Gill system only serves as a covering for the stent delivery system and can be removed after advancing the stent delivery system due to the longitudinally extending member.

[0030] Although the concept of a tapered member inside the guiding extension catheter is seen in the Root device, prior art systems use a very short taper and do not contemplate the tapered member as an elongate integrated member of the overall system, nor do they contemplate that a pre - dilatation balloon can be attached to the tapered delivery micro - catheter that is to be delivered to the target treatment area. Additionally, the prior art fails to contemplate: a substantially "flush" docking between the inner catheter and the outer guiding extension inside the blood vessel, or that the inner catheter member and the outer catheter member will reversibly assemble or lock together to allow the overall system to be easily moved as a single unit device. The ROOT or other prior art systems do not describe, anticipate, or contemplate a balloon (and / or stent) delivery system with a very low - profile elongate tip and capable of passing beyond the lesion of concern, and a very low - profile elongate tip would be beneficial for achieving coaxial delivery of the guiding catheter extension / balloon system. Such an embodiment has never been commercialized, and the description of the tapered tip inner device only means as a mechanism for proximally delivering the blunt tip of the guiding catheter extension out of the guiding catheter, but never as a mechanism for delivering a balloon (and / or stent) to and beyond the target treatment area in the blood vessel, nor does it contemplate that the integral nature and "flush" interconnection of the inner and outer members will allow the outer delivery "sheath" member to pass through the lesion of concern.

[0031] Therefore, a device and method that will allow the distal portion of a tubular guiding extension system to be delivered to or, ideally, delivered beyond the lesion to be treated will have significant advantages over conventional guiding extension devices, such as "GuidelinerTM" (Teleflex) or "GuidezillaTM" (Boston Scientific), etc.

[0032] Conventional balloon catheters (either wire or rapid exchange) are not integrated with an external delivery sheath, and conventional balloon catheters do not use a tapered delivery microcatheter at the distal end of the catheter. The interventional device (such as a balloon or stent) is to be fixed to the distal end of the catheter to ensure trauma - free advancement into and beyond the lesion site within the blood vessel. Further, none of the conventional balloon catheters are interconnected via an interconnection mechanism to an external delivery sheath (guide catheter extension subsystem), the interconnection mechanism being actuated to permit the conventional balloon catheter and the external delivery sheath to move as a single unit integrally and being de - actuated to permit the balloon catheter to retract from the external delivery sheath while preventing forward displacement of the balloon catheter relative to the external delivery sheath.

[0033] It would be highly desirable and effective to provide an intravascular delivery system that can deliver an interventional device (such as a pre - dilatation balloon) along with a guide catheter extension subsystem (such as an external delivery sheath) to and beyond a lesion in a substantially trauma - free and convenient manner.

[0034] It would also be highly desirable to provide an intravascular delivery system having both an outer catheter and an inner catheter, both the outer catheter and the inner catheter being characterized by an enhanced distal end having a micro - tapered distal tip profile with a “seamless” distal interface to ensure the system's ability to cross lesions for treatment without trauma.

[0035] Further, it would be desirable to facilitate percutaneous vascular reconstruction procedures by using a balloon with a coiled - enhanced tapered distal tip attached to an inner balloon catheter, the inner balloon catheter being fitted within the outer delivery sheath of the outer catheter, wherein the inner balloon catheter is equipped with a distal elongated tapered coiled - enhanced microcatheter at the tapered distal tip to carry the interventional device (pre - dilatation 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 - dilatation systems. SUMMARY OF THE INVENTION

[0036] Accordingly, an object of the present disclosure is to provide a medical device for intravascular applications that can deliver an interventional device (such as a balloon or stent) to and beyond a coronary obstructive lesion in an effective and minimally invasive manner.

[0037] Another object of the present disclosure is to provide an intravascular delivery system using a coaxial, highly flexible delivery catheter arrangement where the outer catheter and the inner catheter are docked with each other in a “seamless” manner at their distal ends to form a micro - profile, beneficial for achieving the “crossing ability” of a pre - dilatation balloon (or other interventional device) and enhancing the effective and safe distal delivery of the guide extension device.

[0038] An additional object of the present disclosure is to enhance the distal tapered end of a highly flexible coil to deliver a pre - dilatation balloon (or another interventional device) to and / or beyond a target lesion in a diseased human coronary artery to be treated by angioplasty (or stenting).

[0039] A further object of the present disclosure is to provide a guiding catheter extension / pre - dilatation system that uses an outer catheter (outer delivery sheath system) and an inner catheter (interventional device delivery subsystem). The inner catheter (interventional device delivery subsystem) is assembled and interchangeably connectable within the outer sheath of the outer catheter. Both the outer catheter and the inner catheter can be delivered to or beyond the lesion treatment area within a blood vessel. The inner catheter has a delivery tapered micro - catheter at its distal end, and the delivery tapered micro - catheter has a pre - dilatation balloon member (or another interventional device) attached thereto. The pre - dilatation balloon member (or another interventional device) slides along a guide wire in a substantially non - invasive manner.

[0040] A further object of the present disclosure is to provide a guiding catheter extension subsystem (outer member) integrated with a pre - dilatation balloon (or another interventional device) subsystem (inner member), wherein the outer member and the inner member are coupled to each other (via a locking mechanism) to be displaced as a single unit (as the "entire system") along the guide wire to the lesion site. After the pre - dilatation procedure, the guiding catheter extension subsystem (configured with an outer delivery sheath) is unlocked from the inner member and can be advanced beyond the lesion if desired. Subsequently, the inner member (interventional device delivery subsystem) can be withdrawn. If the surgery requires, the outer delivery sheath of the outer member can be retained in the guiding catheter to enhance the delivery ability of a stent (or other interventional device) within the outer delivery sheath to reach the lesion site. After the stent (or other interventional device) has been delivered to the lesion and deployed for final treatment, the outer delivery sheath can be subsequently withdrawn.

[0041] In addition, an object of the present disclosure is to provide a guiding catheter extension / pre - dilatation system equipped with a "locking mechanism" that is operably coupled between the inner member and the outer member (outer sheath) to provide an overall passage for both the inner member and the outer member as a single unit for the convenient and safe delivery ability of the pre - dilatation balloon and the outer sheath to reach and exceed the treatment site.

[0042] A further object of the present disclosure is to provide a guiding extension system configured with a pre - dilatation balloon (or other interventional device) delivery catheter that can be delivered in a non - invasive manner to a treatment site inside a vascular structure to enable easy passage of the balloon (or other interventional device) and the guiding extension system passing through it, thereby accelerating cardiac surgery, which allows performing percutaneous coronary intervention with a lower radiation dose exposure compared to using a conventional system and has the added advantage of having little risk of stent embolization or drug loss of the stent delivery system (using drug - eluting stents).

[0043] A further object of the present disclosure is to provide an intravascular guiding catheter extension / pre - dilatation system configured with coaxial inner and outer catheters that can be displaced relative to each other and are reinforced by coil reinforcements along their lengths, but are increasingly flexible and can achieve improved contrast agent infusion flow rate and embolization prevention, wherein the tapered distal end of the outer catheter can be elastically stretched to form a firm contact with the distal portion of the inner catheter and the nearly flush (smooth) outer surface at the interface between the inner and outer catheters.

[0044] Another object of the present invention is to provide an external guiding extension catheter with side holes to allow distal coronary perfusion during delivery to a distal, tortuous, and / or diseased vessel near the target lesion site. Yet another object of the present disclosure is to provide an external guiding extension catheter with side holes to allow distal coronary perfusion after withdrawing the inner catheter. One or more holes can increase distal perfusion, thereby allowing oxygenated blood flow while the external catheter is deployed within the vessel.

[0045] The present system and method present an intravascular delivery system configured for controlled displacement along a guide wire within a vessel of interest. The system of the present disclosure is formed with a proximal section, a distal section, and an intermediate section located between the proximal section and the intermediate section. The current system includes an outer member formed of an elongated outer delivery sheath having a flexible substantially cylindrical profile that defines a sheath lumen having a proximal end and a distal end. The outer delivery sheath extends between the intermediate section and the distal section 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 that extends in a cylindrical manner 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 decrease in size from the proximal edge to the distal edge of the tapered outer tip. The proximal (wire or subcutaneous tube) element (push or pull) of the tubular structure connected to the outer member can be low-profile and "flexible" (not "rigid") to allow enhanced compliance within the guiding catheter and a lower profile than the rigid "pushing" element in a conventional guiding extension catheter (according to Root). This is facilitated by the "pushability" of the "entire system" achieved through the locking and integral connection between the outer catheter (and its subcutaneous tube push / pull element) and the inner catheter (guiding extension tube).

[0046] The system of the present disclosure further includes an inner member (inner catheter) having an elongated body that defines an inner channel extending along its longitudinal axis. The inner member extends internally along the sheath lumen of the outer member (outer catheter) in a controllable relationship with the outer delivery sheath. The elongated body of the inner member has a tapered distal portion having an outer diameter and is configured with a tapered delivery catheter having an elongated body of a predetermined length. The tapered delivery catheter of the inner member is capable of being displaced 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 less than the outer diameter of the tapered distal portion of the inner member at the region where the two elements form a distal junction.

[0047] The interconnect mechanism is operably coupled between the inner member and the outer member and is controllably actuated to operate the guide catheter extension / pre-dilation subsystem in an engaged or disengaged operating mode. In the engaged operating mode, the inner and outer members of the guide catheter extension subsystem are engaged for controlled co-displacement along the guide wire. This also allows for enhanced "pushability" of the systems of the present disclosure (where the outer member is connected and locked to the inner member), even though the connected pusher (push / pull element) of the outer member has a micro-profile and is flexible (as flexible or more flexible than the outer tubular sheath of the outer catheter). In the disengaged operating mode, after pre-dilation treatment or stent delivery, the inner and outer members are disengaged to retract the inner member from the outer member.

[0048] The distal portion of the inner member abuts the inner surface of the tapered outer end of the sheath lumen at its outer surface. The dimensional transition between the outer diameter of the outer end of the sheath lumen and the outer diameter of the distal end of the inner member forms a substantially flush interface transition therebetween.

[0049] The tapered outer end of the outer member has an elastic expansion configuration. At the proximal end of the outer sheath (also referred to herein as the middle rod member portion of the outer member), the outer sheath is configured with an inlet opening whose circumference exceeds the circumference of the tubular body of the outer sheath. In some embodiments, the inlet opening at the proximal end of the outer sheath is funnel-shaped.

[0050] The outer sheath is preferably reinforced along its length. The outer member includes a distal soft end encapsulation material that encapsulates the reinforced sheath of the outer member at the distal end of the outer member. The distal soft end encapsulation material is a flexible low-hardness elastomeric material having a gradient hardness value that increases from the distal end of the sheath towards the proximal end.

[0051] The outer member further includes a distal lubricious liner that is sandwiched between the outer surface of the outer sheath and the inner surface of the distal soft end encapsulation material.

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

[0053] The balloon member is attached to the tapered distal portion of the inner member near the tapered delivery microcatheter, and an inflation lumen extends within the inner member between a proximal section and the balloon member at the distal section to provide a fluid path between an external balloon inflation system and the balloon member. The balloon member may assume an inflated configuration or a deflated configuration. In the deflated configuration, the balloon member is displaced within the blood vessel. After being positioned at least in alignment with the treatment site for pre-dilation surgery, the balloon member is controllably transformed into the inflated configuration.

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

[0055] The pusher / puller element of the outer catheter, which is configured with a flat portion at its distal side, 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. Such a 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 within the guiding catheter and a lower profile than a rigid "pushing" element (such as a Root) in a conventional guiding extension catheter.

[0056] The interconnect mechanism can include a snap-fit locking mechanism that is configured with a proximal coupler and a mating element, the proximal coupler being disposed at the proximal end of the sheath of the outer member (catheter), and the mating element being disposed at the outer surface of the elongate body of the inner member (catheter). The proximal coupler can include a distal continuous ring and a middle split ring, the middle split ring being positioned a predetermined distance from the continuous ring, and the mating member includes a member selected from the group including a middle displaced locking ring, a square annular member, a snap cage, and other similar members. The mating member is attached to the outer surface of the elongate body of the inner member. When the mating member is snap-fitted and locked between the distal continuous ring and the middle opening ring, a locking engagement between the outer member and the inner member is achieved. The proximal pusher / puller element and coupler of the outer catheter can be made of a memory metal (such as nitinol) to prevent deformation during antegrade or retrograde movement of the outer member and to prevent any deformation of the middle rod coupler (also referred to herein as the proximal coupler) during passage of a stent or other device through the middle rod portion of the outer catheter.

[0057] The proximal coupler further includes a proximal bevel split ring at its proximal end, the proximal bevel split ring enhancing the funnel-shaped proximal inlet of the outer member and preventing damage or permanent deformation of the funnel-shaped proximal inlet caused by displacement of the inner member or stent delivery system within the funnel inlet. The coupler and the middle rod inlet can have an inlet opening (or "mouth"), the perimeter of which is greater than the perimeter of the flexible tubular outer sheath structure of the outer member.

[0058] The intravascular system of the present disclosure further includes a guide wire that can be advanced in a vessel of interest to at least a treatment site, wherein the guide catheter extension subsystem is configured to be controllably displaced along the guide wire. In one of the embodiments of the system of the present disclosure, an elastic outer sheath encapsulates the inner member at least at its proximal end and encapsulates the pusher / puller of the inner member at least along its distal end. The proximal end of the inner member is connected to the pusher / puller by fusing the elastic outer sheath to the length of the proximal end of the inner member and tightly supporting the pusher / puller of the inner member in the elastic outer sheath.

[0059] The push-pull element (or its outer sheath) of the outer catheter may be color-coated to have a unique color that distinguishes the push-pull element (or its outer sheath) of the outer catheter from the push / pull element of the inner catheter, and from the typical gray or silver color of a coronary guide wire. Alternatively, for the convenience of the surgeon, the elastic outer sheath of the inner member may be color-coated to distinguish the pusher / puller of the inner member from the colors of other elements in the system of the present disclosure.

[0060] These and other objects and advantages of the present disclosure will become apparent to those of ordinary skill in the art after reading the detailed description of the present disclosure in conjunction with the patent drawings. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0062] Figures 2A to 2C Schematically describes the guide catheter extension / pre-dilation system of the present disclosure, wherein Figure 2A shows the assembled inner catheter and outer catheter, Figure 2B details the inner catheter, and Figure 2C details an intermediate section of the system of the present disclosure;

[0063] Figures 3A to 3D represents an intermediate section of the inner catheter of the present disclosure, Figure 3A shows a longitudinal section of an inflation lumen subcutaneous injection tube interconnected with an inflation lumen distal rod in the inner catheter, Figure 3B details a longitudinal section of the cut portion of the inflation lumen subcutaneous injection tube, Figure 3C shows a longitudinal section of the inner catheter depicting an RX guide wire (RW) port formed in the inflation lumen distal rod, and Figure 3D shows an isometric view of the RX port portion of the inner catheter shown in Figure 3C ;

[0064] Figure 4 Shows a longitudinal section of the inner catheter, which details the distal end of the inflatable subcutaneous injection tube at the junction with the distal member of the inflation lumen;

[0065] Figures 5A to 5C Depicts the distal section of the system of the present disclosure, Figure 5A Depicts the inflated balloon member, Figure 5B Shows the deflated balloon member, and Figure 5C Details the inflation lumen / balloon junction;

[0066] Figures 6A to 6B Depicts a longitudinal section of the distal section of the inner catheter of the present disclosure, which details 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 Depicts the distal end of the outer catheter;

[0068] Figures 8A to 8B Details the docking of the inner catheter and the outer catheter at their distal ends, wherein, Figure 8A Represents the tapered distal end of the inner catheter, and Figure 8B Depicts the connection point between the inner catheter and the outer catheter at a slightly enlarged scale;

[0069] Figures 9A to 9D Represents an alternative embodiment of the elastically stretchable distal end of the outer catheter, which is configured with an inflatable split ring ( Figure 9A ), an inflatable end stent ( Figure 9B ) and a slit ( Figures 9C to 9D );

[0070] Figures 10A to 10G Depicts a side view ( Figure 10A , Figure 10B , Figure 10D , Figure 10F ) and an isometric view ( Figure 10C , Figure 10E , Figure 10G ) of an alternative embodiment of the proximal portion of the outer catheter of the present disclosure;

[0071] Figures 11A to 11C Details the design of the coupler at the proximal end of the outer catheter, wherein, Figure 11A Depicts an isometric view of the flat subcutaneous injection tube pusher, Figure 11B Is an isometric view of the proximal end of the outer catheter, and Figure 11CDepicts a side view of a coupler at the proximal end of an outer catheter, the coupler featuring a snap-fit locking mechanism;

[0072] Figures 12A to 12C Depicts an alternative embodiment of the proximal portion of the outer catheter of the present disclosure, Figure 12A is an isometric view of the proximal coupler, Figure 12B is an isometric view of the encapsulated proximal coupler, and Figure 12C is a side view of the encapsulated proximal coupler;

[0073] Figures 13A to 13B Shows an isometric view ([ Figure 13A ) and a side view ([ Figure 13B ) of another embodiment of the proximal coupler at the proximal end of the outer catheter;

[0074] Figures 14A to 14B Depicts a welded-ring embodiment of the proximal inlet of the outer catheter, wherein, Figure 14A shows the welded-ring coupler, and Figure 14B shows the encapsulated welded-ring coupler;

[0075] Figures 15A to 15D Depicts additional alternative embodiments of the proximal coupler of the outer catheter, Figures 15A to 15B are a side view and an isometric view, respectively, of a funnel-shaped fenestration with a circular profile, and Figures 15B to 15D are a side view and an isometric view, respectively, of a funnel-shaped fenestration with a triangular profile;

[0076] Figures 16A to 16C Represents the subcutaneous injection tube pusher flushing lumen concept, Figure 16A Depicts an isometric view of the proximal coupler of the outer catheter coupled to the pusher, Figure 16B is Figure 16A an isometric cross-sectional view that depicts the flow channel in the pusher, and Figure 16C shows the procedure for injecting a flushing fluid between the inner catheter and the outer catheter;

[0077] Figures 17A to 17C Depicts the central rod annular ring locking mechanism of the present disclosure, wherein, Figure 17A shows the "lock disengaged" operating mode, Figure 17B shows the "lock engaged" operating mode, and Figure 17C represents the annular ring in the locking mechanism of the present disclosure;

[0078] Figures 18A to 18B Details the annular ring locking mechanism of the present disclosure shown in Figures 17A to 17B wherein, Figure 18A depicts a proximal coupler configured with locking recesses for engaging with ( Figure 17Ccircular ring joint, and Figure 18B is a longitudinal section of internal / external catheters that are locked to each other;

[0079] Figures 19A to 19C depicts an alternative embodiment of the locking mechanism of the present disclosure, which features a middle rod "square" ring; Figure 19A shows an internal catheter equipped with a ring locking mechanism; Figure 19B shows the ring of the internal catheter snapped into the proximal coupler of the external catheter, and Figure 19C depicts a cross-sectional view of the square ring;

[0080] Figures 20A to 20C depicts an alternative "snap-fit cage" type locking mechanism; Figure 20A shows an internal catheter with a welded cage lock; Figure 20B shows the welded cage lock of the internal catheter snapped into the proximal coupler of the external catheter, and Figure 20C is an isometric view of the welded cage element;

[0081] Figure 21 is a side view of another embodiment of the proximal coupler of the external catheter, which features two locking slots;

[0082] Figures 22A to 22B represents a monorail microcatheter embodiment of the system of the present disclosure; Figure 22A depicts an isometric view of the monorail microcatheter embodiment, and Figure 22B shows a side view taken along line A-A;

[0083] Figures 23A to 23C details the monorail microcatheter embodiment of the present disclosure; Figure 23A shows an isometric view of the proximal portion of the internal catheter connected to the subcutaneous injection tube pusher; Figure 23B details the proximal end of the pusher at a slightly enlarged scale, and Figure 23C is a side view of the proximal portion of the internal catheter connected to the subcutaneous injection tube pusher; and

[0084] Figure 24A and Figure 24B respectively depict an isometric view and a side view of a coil-enhanced balloon catheter embodiment of the system of the present disclosure.

[0085] Figure 25 is a perspective view of an embodiment of the external catheter, which is configured with multiple holes in an external delivery sheath.

[0086] Figure 26 is a perspective view of an embodiment of the external catheter, which is configured with multiple holes in an external delivery sheath.

[0087] Figure 27 Schematic diagram of an embodiment of an external catheter, the external catheter being configured with a plurality of holes in a proximal section within an external delivery sheath.

[0088] Figure 28 Schematic diagram of an embodiment of an external catheter, the external catheter being configured with a plurality of holes in proximal and distal sections within an external delivery sheath.

[0089] Figures 29A to 29C Shows various examples of the placement of holes in the sheath. Figure 29A Shows an embodiment having holes in the distal and proximal sections of the sheath. Figure 29B Shows an embodiment having holes in the distal, intermediate, and proximal sections of the sheath. Figure 29C Shows an embodiment having holes in the proximal, intermediate, and distal sections of the sheath.

[0090] Figure 30 Perspective view of an embodiment of an external catheter, the external catheter being configured with a plurality of holes within an external delivery sheath.

[0091] Figures 31A to 31C Shows various examples of the size of the holes in the sheath. Figure 31A Shows an embodiment in which the holes have a substantially uniform diameter. Figure 31B Shows an embodiment in which the holes have a varying diameter. Figure 31C Shows yet another embodiment in which the holes have a varying diameter.

[0092] Figures 32A to 32C Shows various examples of the axial spacing between the holes in the sheath. Figure 32A Shows an embodiment in which the holes are axially spaced apart on the sheath at a substantially uniform axial interval. Figure 32B Shows another embodiment in which the holes are axially spaced apart on the sheath at a varying axial interval. Figure 32C Shows yet another embodiment in which the holes are axially spaced apart on the sheath at a varying axial interval.

[0093] Figures 33A to 33C Shows various examples of the radial position of the holes in the sheath. Figure 33A Shows an embodiment in which the holes are positioned on the sheath at a substantially uniform radial position. Figure 33B Shows another embodiment in which the holes are positioned on the sheath at a varying radial position. Figure 33C Shows another embodiment in which there are holes at multiple radial positions at a single axial position on the sheath.

[0094] Figures 34A to 34C Shows embodiments of various non-circular holes in the sheath.Figure 34A An embodiment is shown in which the hole is oval. Figure 34B Another embodiment is shown in which the hole is oblong. Figure 34C Yet another embodiment is shown in which the hole is rectangular. Detailed Description

[0095] In Figures 1 to 24B the intravascular delivery system 10 of the present disclosure is described. The intravascular delivery system 10 includes a guide catheter extension subsystem (also referred to herein as an external catheter or external member) and an interventional device delivery subsystem (also referred to herein as an internal catheter or internal member). The guide catheter extension subsystem and the interventional device delivery subsystem cooperate with each other under the control of a surgeon during a cardiac operation. Although the interventional device delivery subsystem can be used to deliver various cardiac interventional devices, in one embodiment, by way of example only and not limiting the scope of the invention to this specific embodiment, the interventional device delivery subsystem of the present disclosure will be further described as being adapted to deliver a balloon member for performing a pre-dilation procedure.

[0096] In the exemplary embodiment described herein, the system 10 of the present disclosure can be referred to herein as a guide catheter extension / pre-dilation system. The guide catheter extension / pre-dilation system can be used in combination with a guide wire 12 and a guide catheter 14 for a cardiac operation. As Figure 1 shown, at the initial stage of a cardiac operation, a surgeon moves the guide wire (GW) 12 into a blood vessel 16. The guide catheter 14 is advanced along the guide wire 12 through the blood vessel 16 (such as the aorta) to a position adjacent to the ostium 18 of the coronary artery 20. The guide wire 12 can be used to guide the guide catheter 14 during a cardiac operation, and then the guide catheter extension / pre-dilation system 10 of the present disclosure (inside the guide catheter 14) can extend within the artery 20 toward a target location 22, as will be described in detail in the following paragraphs.

[0097] As Figures 2A to 2C shown, the guide catheter extension / pre-dilation system 10 of the present disclosure includes a balloon catheter subsystem 34 (also referred to herein as an internal catheter, internal member, or pre-dilation subassembly) and a guide catheter extension subsystem 36 (also referred to herein as an external catheter). The internal catheter 34 interacts with the external catheter 36 and can be engaged or disengaged from the external catheter 36 as needed for a cardiac operation.

[0098] The system 10 of the present disclosure includes a proximal section 38, a distal section 40, and an intermediate section 42 that extends between and interconnects the proximal section 38 and the distal section 40. A pre - dilatation balloon member 44 is carried at the distal section 40 of the inner catheter 34. The distal section 40 of the inner catheter 34 may also be configured with an elongate tapered micro - catheter 46, as will be described in detail in the following paragraphs.

[0099] As Figure 1 shown, the guide extension / pre - dilatation system 10 of the present disclosure extends within the lumen (inner passage) 48 of the guide catheter 14. To reliably reach the target location 22 and, in some cases, extend beyond the target location 22, the guide extension / pre - dilatation system 10 of the present disclosure is advanced through the guide catheter 14 beyond the distal end 50 of the guide catheter 14 deep into the coronary artery 20. The system 10 of the present disclosure provides sufficient accessibility of the pre - dilatation 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 ostium 18 of the coronary artery 20, and allows improved ease of entry of the system 10 of the present disclosure into the coronary artery 20 and accessibility to the target site 22.

[0100] As Figure 1 、 Figures 2A to 2B 、 Figures 3C to 3D 、 Figure 4 、 Figures 5A to 5C and Figure 6A shown, the guide wire 12 extends within the guide catheter extension / pre - dilatation system 10 and exits the system 10 with the distal end of the GW 12 beyond the outermost end 52 of the distal section 40 and with the proximal end of the GW 12 at the intermediate section 42.

[0101] In operation, the inner catheter 34 and the outer catheter 36 are coupled to each other to be advanced (as a single unit) along the guide wire 12 within the guide catheter 14 positioned within the blood vessel 16 and extend beyond the distal end 50 of the guide catheter 14 to reach the target lesion site 22. Once the balloon catheter subsystem (inner member) 34 of the present disclosure reaches the lesion site 22 and the balloon member 44 is positioned to align with the lesion site 22, the intended pre - dilatation procedure can be performed. Once the pre - dilatation has been performed, the outer catheter (also referred to herein as the outer member) 36 can be advanced as an integral unit with the inner catheter (also referred to herein as the inner member) 34 through the lesion, and then the inner catheter 34 is disengaged from the outer catheter 36 to withdraw the inner catheter from the outer catheter.

[0102] Alternatively, after a pre-dilation procedure has been performed, the inner catheter 34 can be disengaged from the outer catheter 36 while the outer catheter 36 is advanced through the dilated lesion. Additionally, after pre-dilation has been performed and the inner catheter 34 has been removed, the outer catheter 36 can be left near the lesion.

[0103] In any case, the outer member (catheter) 36 remaining near the pre-dilated lesion can be used to deliver a stent within the outer member (catheter) 36 to the lesion site. Once the stent has been deployed at the lesion site, the outer member 36 is removed from the guiding catheter 14.

[0104] As will be shown in further paragraphs, in the system of the present disclosure, forward displacement of the inner catheter 34 within the outer catheter 36 is prevented. Only backward or removal displacement of the inner member 34 relative to the outer member 36 is permitted to support retraction of the inner member from the outer member after pre-dilation of the lesion.

[0105] Reference Figures 2A to 2C , the proximal section 38 of the guiding extension / pre-dilation system 10 of the present disclosure is represented by the balloon inflation hub 56 of the inner member 34 (best depicted in Figure 2B ) and the proximal end 58 of the outer member 36.

[0106] Reference Figure 2B 、 Figures 3A to 3D 、 Figure 4 and Figure 5C , the inner member (sometimes also referred to herein as the balloon catheter subsystem or pre-dilation balloon delivery subsystem) 34 is configured with an inner inflation channel 60 that extends between the inflation hub 56 and the pre-dilation balloon member 44. The inner inflation channel 60 serves as a passage for inflation air between the balloon inflation system 62 (schematically shown in Figure 2B ) and the balloon member 44 to effect controlled inflation / deflation of the balloon member 44 as prescribed for cardiac procedures.

[0107] The inner inflation channel 60 is formed by an inflation lumen subcutaneous injection tube 64 and an inflation lumen distal rod 66 that are interconnected in a fluid-tight manner with overlapping each other.

[0108] The inflation hub 56 located at the proximal end 68 of the inner member 34 is configured with an inner tapered channel 70 that is connected to the balloon inflation system 62 through its proximal opening 72 (as schematically shown in Figure 2B ).

[0109] The balloon inflation system 62 can be a manual or an 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 (the electromagnetic pressure valve is fluidly coupled to the balloon inflation hub 56) to control the pressurization / de-pressurization of the balloon member 44 using a fluid or air flow.

[0110] As Figure 2B shown, the internal tapered channel 70 of the balloon inflation hub 56 is configured with a distal opening 74, and the distal opening 74 is coupled to the inflation lumen subcutaneous injection tube 64. The proximal end of the inflation lumen subcutaneous injection tube 64 is fluidly sealed to the distal opening 74 of the internal tapered channel 70 of the balloon inflation hub 56 to support the passage of inflation air between the balloon member 44 and the inflation system 62.

[0111] The inflation lumen subcutaneous injection tube 64 extends through the length of the proximal section 38 and a portion of the intermediate section 42 of the system 10 of the present disclosure, and terminates at the distal section 40 with the distal end 78 of the inflation lumen subcutaneous injection tube 64, as Figure 2B and Figure 4 shown.

[0112] As Figure 2B shown, a flexible serrated member 80 is provided at the proximal end 76 of the inflation lumen subcutaneous injection tube 64, and the flexible serrated member 80 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 subcutaneous injection tube 64 and provides structural flexible bending when manipulated by the surgeon.

[0113] As Figures 2A to 2C , Figures 3A to 3D , Figure 4 and Figure 5C 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 Details the junction between the inflation lumen subcutaneous injection tube 64 and the inflation lumen distal rod 66. The inflation lumen subcutaneous injection tube 64 does not extend all the way through the internal member 34, but terminates at the distal end 78 of the inflation lumen subcutaneous injection tube 64 (as Figure 2B and Figure 4 shown).

[0114] Refer to Figures 3B to 3D, the inflation lumen subcutaneous injection tube 64 has a cut distal portion 90, and the cut distal portion 90 is coaxially encapsulated by the wall of the inflation lumen distal rod 66, such that the inflation lumen subcutaneous injection tube 64 together with the inflation lumen distal rod 66 provides a sealed fluid communication between the balloon inflation system 62 and the inner chamber 92 of the balloon member 44, as Figures 5A to 5C shown, for controlling the inflation / deflation of the balloon member 44 according to the needs of cardiac surgery.

[0115] Figure 2B and Figures 3C to 3D shows that the inflation lumen distal rod 66 is configured with a rapid exchange (RX) guide wire (GW) port 94, and the GW lumen 96 starts at its proximal end 98 at the port 94. The GW lumen 96 extends through the entire length of the distal section 40 of the inner catheter 34 between the RX GW ports 94 inside the inflation lumen distal rod 66. The GW lumen 96 forms an internal channel that has a proximal end 98 and a distal end 100, the proximal end 98 corresponding to the RX GW port 94, and the distal end 100 corresponding to the outermost distal end 52 of the distal section 40 of the inner member 34. As Figures 6A to 6B shown, at the distal section 40, the GW lumen 96 extends beyond the distal end 102 of the inflation lumen distal rod 66. The distal end 100 of the GW lumen 96 constitutes a tapered portion 104, and the tapered portion 104 can be in the form of a delivery microcatheter 46.

[0116] Referring to Figures 2A to 2B , Figures 5A to 5C , Figures 6A to 6B and Figures 24A to 24B , the inner catheter (also referred to herein as the balloon catheter subsystem) 34 is configured with a tapered distal portion (sometimes also referred to herein as the tapered distal tip) 162 at the distal section 40. The tapered distal portion 162 is equipped with a pre - dilatation balloon member 44, and the pre - dilatation balloon member 44 is fixedly attached to the tapered distal portion 162 near the microcatheter 46. The pre - dilatation balloon member 44 is fixed to the tapered distal portion (tip) 162 of the inner member for supporting the pre - dilatation / stent implantation procedure required for the patient's cardiac treatment.

[0117] The balloon member 44 has a proximal portion 112 and a distal portion 114. The balloon member 44 is attached (fixed) near the delivery microcatheter 46 at the distal section 40, wherein the proximal portion 112 of the balloon member 44 is coupled to the distal end 102 of the inflation lumen distal rod 66, and the distal portion 114 of the balloon 44 is coupled to the outer surface of the microcatheter 46.

[0118] As Figures 5A to 5CAs shown, the pre - dilatation balloon 44 has its proximal portion 112 attached to the proximal portion 204 of the distal end 162 adjacent and juxtaposed to the outer end 164 of the sheath 120, and its distal portion 114 attached to the distal end 166 of the distal portion (end) 162 of the inner member 34.

[0119] The balloon member 44 can intermittently assume a deflated (folded) configuration and an inflated (expanded) configuration. The deflated (folded) configuration is used during insertion and / or withdrawal of the system of the present disclosure relative to a blood vessel. The balloon is inflated (expanded) when in position (at the target site 22) to widen the blood vessel and compress plaque for pre - dilatation procedures, or (when a stent is delivered to the treatment site on the balloon) for stent implantation procedures. When inflated, the balloon 44 assumes the inflated / open configuration shown in Figures 2A to 2B 、 Figure 5A 、 Figure 5C 、 Figures 6A to 6B and Figures 24A to 24B for pre - dilatation of diseased blood vessels. When deflated, the balloon member 44 assumes the deflated configuration shown in Figure 5B .

[0120] The balloon 44 can have a smooth surface or a "chocolate" configuration. A "chocolate" balloon catheter is a wire - mounted balloon dilatation catheter having a braided shaft and a non - traumatic tapered tip. The balloon is restricted by a nitinol structure when inflated, which forms small "pillows" and grooves in the balloon.

[0121] Now referring to Figure 2A 、 Figure 2C 、 Figures 5A to 5C 、 Figure 7 、 Figures 8A to 8B 、 Figure 9A 、 Figures 9C to 9D 、 Figures 10A to 10G 、 Figure 11C 、 Figures 12B to 12C 、 Figures 13A to 13B 、 Figure 14B 、 Figures 15A to 15D 、 Figures 16A to 16B 、 Figures 17A to 17B 、 Figures 18A to 18B 、 Figure 19B 、 Figures 20A to 20B 、 Figure 21 and Figures 24A to 24B , the outer catheter (also referred to as the guiding catheter extension subsystem) 36 is formed with a cylindrical outer delivery sheath 120 having an internal channel 122 extending along its interior. A coupler mechanism 130 is formed at the proximal end 132 of the cylindrical sheath 120 in a circumferential relationship with the cylindrical sheath 120.

[0122] At the proximal end 58, the outer catheter 36 includes an outer member pusher (also referred to herein as a pusher / puller) 134, as Figure 10B FIGS. Figure 10G , Figures 11A to 11C , Figures 12A to 12C , Figures 13A to 13B , Figures 14A to 14B , Figures 15A to 15D , Figures 16A to 16B , Figures 17A to 17B , Figures 18A to 18B , Figure 19B and FIG. 22 illustrate. In one embodiment, the outer member pusher 134 can be an unbroken line that can have a circular wire proximal section 136 and a flat distal section 138, and the flat distal section 138 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.

[0123] Alternatively, the circular pusher wire can be welded to the flat wire, which in turn is welded or otherwise fixedly attached to the proximal end 132 of the sheath 120.

[0124] In yet another alternative embodiment of the outer member 36, the circular wire can be welded or otherwise fixedly attached to two flat wires, which in turn are welded or otherwise fixedly attached to the proximal end 132 of the sheath 120.

[0125] The flat profile of the pusher wire portion is welded to the proximal coupler 130 of the outer sheath 120 such that, as required for the surgery: when the inner member 34 is inserted within the outer member (catheter) 36, the pusher wire does not impede the rotational or longitudinal movement of the inner catheter 34 within the proximal coupler 130 of the outer member 36 and within the sheath 120. The proximal push-pull element 134 advances or retracts with the outer tubular sheath 120 and is preferably flexible (non-rigid). The pusher / puller 134 can be flexible (non-rigid), and the flexibility along the longitudinal axis of the pusher / puller 134 is equivalent to or exceeds the flexibility of the tubular outer delivery sheath 120 of the outer catheter 36.

[0126] As Figure 10F illustrates, the pusher 134 of the outer catheter can be equipped with a proximal handle 140 at its proximal end to facilitate a surgeon performing a coronary intervention procedure to manipulate the outer member 36 in order to position the outer delivery sheath 120, together with the balloon delivery subsystem 34, at a desired location relative to the lesion 22 in the diseased blood vessel.

[0127] The push / pull element 134 (of a wire or subcutaneous injection tube configuration) proximal to the tubular structure 120 connected to an external member achieves enhanced compliance inside the guiding catheter and a lower profile than the rigid "pushing" element (as per Root) in a conventional guiding extension catheter by having a micro-profile and flexibility (not "rigid"). This is due to the "pushability" of the "entire system" achieved through a locking integral connection between the external catheter (and the subcutaneous injection tube pushing element of the external catheter) and the internal catheter (guiding extension tube).

[0128] In addition, the internal catheter (internal member) 34 can be equipped with a pusher of the internal member (also referred to herein as a pusher / puller) 142 (as Figure 2A shown), and the pusher 142 of the internal member can be attached to the inflation hub 56 to facilitate withdrawal of the internal member 34 from the external member 36 as needed for coronary intervention procedures, and to control the engagement / disengagement between the internal member 34 and the external member 36 for various stages of cardiac surgery. The pusher / puller 142 of the internal member can be formed with a handle of the internal member pusher / puller to facilitate the surgeon in performing the surgery.

[0129] The handles of the pushers of the internal member and the external member can be configured with mechanisms (detailed in U.S. Patent Application #15 / 899,603, which is incorporated herein by reference) that permit additional releasable locking between the internal member and the external member to enhance the overall fit between the internal member and the external member in the engagement operating mode.

[0130] The internal member 34 can be a wire-on construction or an RX construction. In one of the embodiments detailed herein, the guide wire 12 extends through the RX GW port 94 formed at the proximal end of the distal member 66 of the tubular inflation lumen, enters the internal channel 146 of the GW lumen 96, and extends along the internal channel 146 of the GW lumen 96, as Figures 3C to 3D and Figure 4 shown. At the distal section 40 of the system 10 of the present disclosure, the guide wire 12 extends along the delivery tapered microcatheter 46 (at the tapered portion 104) in the GW lumen and exits the distal end 100 of the GW lumen 96 at the outermost end 52 of the internal member 34, as Figures 2A to 2B 、 Figures 5A to 5B and Figures 6A to 6B shown.

[0131] 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 of the present disclosure. 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 catheter 14. When a pre-dilation procedure has been performed (as will be detailed 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.

[0132] As Figures 8A to 8B and Figures 9A to 9D shown, the docking between the outer end 164 of the sheath 120 and the distal end 162 of the inner member 34 facilitates the displacement of the distal end 162 of the inner member 34 relative to the outer end 164 of the sheath 120 and, depending on the needs of the cardiac procedure, fundamentally facilitates the displacement of the distal end 162 relative to the outer end 164 of the sheath 120.

[0133] The distal end 160 and the outer end 164 of the sheath 120 are formed of a flexible material that permits the 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.

[0134] The sheath 120 of the outer catheter 36 is configured at its proximal end 132 with an inlet “opening” (or “mouth”) 210, the perimeter of which exceeds the perimeter of the outer member flexible tubular sheath 120, as Figures 10A to 10G shown. The inlet 210 (also referred to herein as the “mouth”) to the inner channel 122 of the sheath 120 can be configured in various variations. For example, as Figure 10A shown, the inlet 210 has a funnel shape 211 that has an eccentric opening (as Figure 10A shown), or has a concentric blunt profile (as Figures 10B to 10C shown), or has a concentric bevel (as Figures 10D to 10E shown), or alternatively has a concentric concave profile (as Figures 10F to 10G shown). The pusher 134 is attached at a predetermined point on the proximal inlet 210 of the funnel-shaped outer catheter.

[0135] As Figure 2A 、 Figure 2C 、 Figure 7 and Figures 8A to 8BAs shown, the outer delivery sheath 120 of the outer catheter 36 extends between the proximal end 132 of the outer delivery sheath 120 at the intermediate section 42 and the distal end 160 of the outer delivery sheath 120 at the distal section 40 of the system 10 of the present disclosure. At the distal section 40 of the guiding catheter extension / pre - dilation system 10 of the present disclosure, the inner member 34 is configured with a tapered structure 104 having a distal tapered portion (also referred to herein as the distal tapered tip) 162, and the distal tapered portion 162 can be formed with a micro - catheter 46, as Figures 2A to 2B , Figures 5A to 5B , Figures 6A to 6B , Figure 8A , Figures 22A to 22B and Figures 24A to 24B shown. The micro - catheter 46 is an elongated and slender member with a length in the range of cm, such as 1 - 3 cm. The micro - catheter 46 has a tapered conical profile structure with a diameter not exceeding 1 mm at its distal end 52. The micro - catheter 46 can be integrally formed with the tapered distal tip 162 of the inner member 34.

[0136] As Figure 2A , Figures 5A to 5C , Figure 7 and Figures 8A to 8B shown, at the distal end 160, the outer delivery sheath 120 is formed with an outer tip 164 having a tapered conical profile structure, and the tapered conical profile structure can be interconnected with the distal tip 162 of the inner member 34. The outer tip 164 of the outer member 36 provides a smooth distal taper transition between the distal end 160 of the sheath 120 and the distal section 40.

[0137] In Figure 2A , Figures 5A to 5B , Figures 6A to 6B , Figures 8A to 8B , Figures 22A to 22B and Figures 24A to 24B , the distal tip 162 of the inner catheter 34 is shown to have a tapered structure that gradually changes from the interconnection point with the outer tip 164 of the sheath 120 to the distal end 166 of the distal tip 162. The micro - catheter 46 extends (with a length of about 1 - 3 cm) from the distal end 166 of the distal tapered portion 162 of the inner member 34 in a manner integrally connected to the inner member, and terminates at the outermost distal end 52.

[0138] The guiding catheter extension / pre - dilation system 10 of the present disclosure can be configured to be more flexible in the distal portion, have a substantially lower profile, and be more flexible in the distal portion of the guiding catheter extension subsystem (outer delivery sheath) through the differentiation of the flexibility of the micro - catheter, wherein the differentiation of the flexibility of the micro - catheter is achieved by the following means: changing the hardness of the plastic (polymer) component from the proximal portion to the distal portion of the outer delivery sheath (i.e., using 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 micro - catheter 46 in the direction from the proximal portion to the distal portion, such that the distal portion of the micro - catheter 46 is more flexible and more tractable than the proximal portion of the micro - catheter delivery device.

[0139] The system 10 may further include radiopaque wires such that the balloon member 44, the micro - catheter 46, and the outer delivery sheath 120 are easily visualized using fluoroscopy. It is contemplated that the distal tip 162 (as Figure 5A , Figures 6A to 6B shown) is provided with radiopaque markers 264, 266 near the proximal portion 112 and the distal portion 114 of the balloon 44. The radiological markers 264, 266 allow the surgeon (operator) to visualize the positioning of the balloon member 44 relative to the lesion location 22.

[0140] In addition, the outermost distal tip 52 of the micro - catheter delivery portion 46 and the tip 160 of the sheath 120 may have one or more radiopaque markers 268, 270 (as Figure 2B and Figure 5A shown) in order to allow the surgeon to distinguish the radiological markers, which is particularly important when an obstructive lesion is traversed by the micro - catheter and the balloon member carried near the micro - catheter is held in place.

[0141] As detailed in Figure 7 , in one of its embodiments, the outer catheter 36 is configured with a system of catheter rod coil reinforcements 170, and the catheter rod coil reinforcements 170 are disposed on the inner surface 152 of the sheath 120 (or embedded in the inner surface 152 of the sheath 120). Preferably, a lubricious liner 172 is positioned inside the rod 120. The rod reinforcement coil 170 can be disposed inside the rod 120 in contact with the lubricious liner 172, i.e., in a circumferential relationship with the surface of the lubricious liner 172 that covers the inner surface 152 of the rod 120. The distal soft tip sheath 174 is attached to the distal end of the outer catheter rod 120 along the longitudinal axis 176 of the outer catheter 36.

[0142] The distal soft tip sheath 174 can be glued to the rod 120 at the end 175 (as Figure 7 shown), or can cover a portion of the length of the outer surface 173 of the rod 120.

[0143] The distal flexible end sheath 174 extends beyond the coil reinforcement 170 and the lubricious 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.

[0144] The lubricious liner 172 may be formed of a PTFE material. The distal flexible end 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.

[0145] As Figure 7 and Figures 8A to 8B shown, in one of the preferred embodiments, the inner diameter of the sheath 120 at its inner surface 152 is approximately 0.048", while the outer diameter of the shaft 120 at its outer surface 173 is 0.058". The inner diameter of the tapered portion 178 of the outer catheter 36 at the distal edge 184 is ~0.045", while the outer diameter of the tapered portion 178 at its distal edge 184 is ~0.047". The gradient between the outer diameter of the sheath 120 (0.058") and the outer diameter of the tapered portion 178 (0.047") defines a tapered outer surface, while the gradient between the inner diameter of the sheath 120 (0.048") and the inner diameter of the tapered portion 178 at its distal edge 184 (0.045") defines a tapered inner surface. The thickness of the distal wall 180 of the tapered portion 178 decreases from the interface 182 (between the sheath 120 and the tapered portion 178) to the outermost edge 184 of the tapered portion 178 of the distal flexible end sheath 174.

[0146] As Figure 7 combined with Figures 8A to 8B 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 distal end inner diameter (0.045") of the outer catheter at its outermost distal edge 184. This difference between the outer diameter of the tapered element 104 of the inner catheter 34 and the inner diameter at the distal edge 184 of the outer end 164 of the outer catheter causes stretching of the distal flexible end sheath 174 at its tapered portion 178 when the tapered element 104 of the inner catheter is interfered with. This arrangement provides a nearly seamless transition between the distal end of the inner catheter 34 and the distal end of the outer catheter 36, as well as a micro-profile of the distal end due to the squeezing of the distal end of the inner catheter 34 by the tapered element 178 of the outer catheter 36. When the inner catheter 34 is removed, the elastomeric properties of the distal end of the distal flexible end sheath 174 of the outer catheter 36 permit the tapered portion 178 to return to its original inner diameter (0.045").

[0147] In the detachment operating mode, 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 engagement operating mode, 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.

[0148] Further reference Figures 9A to 9D , the tapered portion 178 is contemplated in several embodiments of the expandable tapered design. As Figure 9A shown, the elasticity of the outer catheter 36 at its distal tapered portion 178 is enhanced by an expandable split ring 190 attached at the tapered portion 178, and the expandable split ring 190 allows the distal outer end 164 to expand (when docking with the inner catheter 34). The expandable split ring 190 has a slit 192 that allows the ring 190 to expand and contract depending on the interference between the inner catheter and the outer catheter at their distal ends. This structure provides additional reinforcement during removal and delivery of the inner catheter of the stent (or balloon) to prevent permanent deformation of the tapered portion 178.

[0149] Reference Figure 9B , in an alternative embodiment of the outer catheter 36, the tapered portion 178 may be configured with an expandable end stent 194, and the expandable end stent 194 may be made of NiTi wire and configured with a distal end 196 and a proximal end 198, and the diameter of the proximal end 198 is greater than the diameter of the distal end 196. Due to the flexibility of the expandable stent 194, the expandable stent 194 expands and contracts when needed and provides additional support to resist permanent deformation of the sheath 174 at the tapered portion 178 during removal of the inner catheter and delivery of the stent or balloon member.

[0150] In Figures 9C to 9D is shown another alternative embodiment of the tapered portion 178 at the distal end of the sheath 120, wherein the wall 180 of the tapered portion 178 is shaped such that slits 200 longitudinally extending along the length of the tapered portion 178 are spread out along the periphery of the wall. When the tapered portion 178 docks with the distal end of the inner member 34, the slits 200 temporarily widen to surround the distal end 162 of the inner catheter 34. This design can prevent permanent deformation of the sheath 174 at its tapered portion 178, which may be caused by removal of the inner catheter 34 or during stent / balloon delivery.

[0151] The important "seamless" aspect of the transition between the outer diameter of the outer end 164 of the sheath 120 (at the tapered portion 178) and the outer diameter of the distal end 162 of the inner member 34 of the system of the present disclosure forms a substantially gradual (smooth) transition therebetween.

[0152] As Figure 2C , Figures 10A to 10G , Figures 11A to 11C , Figures 12A to 12C , Figures 13A to 13B , Figures 14A to 14B and Figures 15A to 15D shown, the system of the present disclosure is constructed with an interconnection mechanism 220 at an intermediate section 42. The interconnection mechanism 220 includes a proximal coupler 130 and a mating mechanism 222. The proximal coupler 130 is formed at a proximal end 132 of a sheath 120 of an outer member 36, and the mating mechanism 222 is formed at an outer surface of an inner member 34 (as detailed in Figures 17A to 17B , Figure 18B , Figures 19A to 19B and Figures 20A to 20C ).

[0153] The guiding catheter extension / pre - dilation system 10 of the present disclosure can operate in an inner / outer catheter engagement mode and an inner / outer catheter disengagement mode, which is accomplished by controlling the interconnection mechanism 220. The interconnection mechanism 220 of the present disclosure is configured to: engage / disengage the inner catheter 34 and the outer catheter 36 (as required for cardiac surgery), and prevent an undesired forward displacement of the inner member 34 inside the outer delivery sheath 120. The engagement operation mode allows enhanced "pushability" of the "entire system" (where 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 compared to the outer tubular sheath 120 of the outer catheter 36).

[0154] When an inner surface 152 of a tubular body 150 of the sheath 120 (at its proximal end 132) engages an outer surface 224 of the mating mechanism 222 (on the inner member 34), the interconnection unit 220 operates based on interference between a proximal coupler 130 configured at the proximal end 132 of the sheath 120 and the mating mechanism 222 configured at the outer surface 224 of the inner member 34.

[0155] By way of example, several interconnection mechanisms can be conceived as being applicable to the guiding catheter extension / pre - dilation system 10 of the present disclosure. The engagement mechanism of the present disclosure is configured for controllable engagement / disengagement between the inner member 34 and the outer member 36, and is configured to prevent forward movement of the inner member 34 relative to the outer delivery sheath 120 beyond a predetermined position.

[0156] For example, as in Figures 11A to 11CAs depicted, the laser cutting coupler 130 can be configured with a proximal opening (slit) ring 240 and a pair of distal rings, the pair of distal rings including a continuous distal ring 242 and an opening (slit) distal ring 244. The proximal opening ring 240, and the distal rings 242 and 244, are integrally formed with the coupler base 246. The coupler 130 can be formed of stainless steel or heat-set NiTi. The pusher / puller element 134 of the outer catheter 36 and the middle displacement coupler (also referred to herein as the proximal coupler) 130 can be made of a memory metal such as nitinol to prevent deformation during antegrade or retrograde movement of the outer member and to prevent any deformation of the middle rod coupler 130 during passage of a stent (or other device) through the middle rod portion of the outer catheter 36.

[0157] The opening ring 240 is associated with the (e.g., funnel-shaped) proximal inlet opening 211 of the outer catheter 36 (shown in Figure 10A , Figures 10D to 10E and Figure 11C ). The proximal opening ring 240 allows the inlet 211 to expand into the funnel 210 as needed for surgical access / removal of the inner catheter 34. As shown in Figure 10A , Figures 10D to 10E and Figures 11A to 11C , the proximal opening ring 240 provides support to the proximal opening 210 of the funnel-shaped proximal end of the sheath 120. The proximal ring 240 reinforces the inlet opening ("mouth") 211 and prevents damage or permanent deformation of the inlet opening, thus supporting the elastic properties of the sheath 120 at the inlet opening 210. The distal rings 242, 244 form a snap-fit locking mechanism separate from the proximal opening ring 240 of the funnel. The distal ring 242 is not expanded (has a closed circular profile), while the opening of the slit ring 244 expands during displacement of the inner catheter 34 relative to the proximal coupler 130 of the outer catheter 36.

[0158] As Figures 11B to 11C shown, the base 246 of the coupler 130 can be flat or, preferably, (in cross-section) slightly bowed to mate with the mating distal end 250 of the pusher 134 having a flat or (in the cross-sectional direction) crescent-shaped profile. The pusher 134 can be made of stainless steel or NiTi. The distal end 250 of the pusher 134 is welded (glued, adhered, or otherwise attached) to the base member 246 of the coupler 130. A PTFE lining (also shown in Figure 7 ) 172 can encapsulate the coupler 130, as shown in Figure 11C .

[0159] The sheath 120 is positioned to surround the coupler and the PTFE lining 172. At the distal end 160 of the sheath 120 (in Figure 7A Pebax encapsulation similar to the distal flexible tip sheath 174 (also shown in Figure 7 ) can be used at the proximal end 132 of the sheath 120. The catheter rod coil reinforcement 170 (also shown in

[0160] As Figures 11A to 11C , Figures 17A to 17C and Figures 18A to 18B shown, the mating mechanism 222 for a particular embodiment shown in Figures 11A to 11C also includes a middle rod locking ring 252 (as shown in Figures 17B to 17C and Figure 18B ), and the middle rod locking ring 252 is used for snap - fit locking.

[0161] In Figures 12A to 12C Another embodiment of the proximal inlet structure of the outer catheter shown in Figures 11A to 11C is similar to the structure shown in

[0162] , with certain modifications, including:

[0163] (a) Increased thickness and additional material around the base 246 of the coupler 130;

[0164] (b) Improved surface treatment (such as sandblasting) to enhance polymer encapsulation adhesion; and

[0165] (c) Using a hard polymer (such as nylon) encapsulation to provide additional support to the funnel to prevent damage that may impede stent access. Figures 13A to 13B Another embodiment of the coupler 130 at the proximal inlet 210 (shown in Figures 13A to 13B ) features a strengthened opening ring (rib) 256 of the inlet port 210. The snap - fit lock 260 is represented by at least two opening rings 262 at the distal end of the coupler 130. As shown in the modifications presented in

[0166] The subcutaneous injection tube pusher / puller 134 can be flat at its distal end 250 and is welded to the base 246 of the coupler 130. The PTFE liner 172 extends under the coupler 130, and the Pebax encapsulation 174 encapsulates the coupler 130 with the pusher 134 attached to it. The catheter rod coil reinforcement structure 170 extends along the rod 120 of the outer catheter 36 from its distal end to its proximal end. The snap - fit lock 260 mates with the one in Figures 17A to 17C18B and the ring embodiment of the mating mechanism 222. In some embodiments, the packaging member 174 and / or the pusher / puller 134 can be colored with different colors, such as Figure 11A As shown, the pusher / puller 134 of the outer member is distinguished from other elements of the arrangement of the present disclosure for the convenience and safety of the surgeon's procedure.

[0167] exist Figures 14A to 14B , wherein the coupler 130 has separate rings 266, 268 that are 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 a central split ring 268, each of which is welded to the pusher 134. A proximal bevel 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 laser cut coupler of a single diameter.

[0168] Figures 15A to 15B Another modification of the proximal coupler 130 is depicted, which features a funnel fenestration that increases the contrast agent infusion flow rate by providing an additional open cross-sectional path for fluid flow. Figures 15A to 15B As shown, a circular opening 272 is formed in the sheath 120. The opening 272 is positioned in a predetermined pattern with the proximal split ring 274 and distal rings 276, 278 of the snap-fit ​​locking structure 280 in a non-obstructive manner. Figures 15C to 15D As shown, the coupler 130 is formed with a triangular opening 282 that is formed in a non-obstructive manner with the proximal and distal rings 274 , 278 , 276 of the snap-fit ​​lock 280 in the sheath 120 .

[0169] Although 15A to Figure 15D Only circular and triangular openings 272, 282, respectively, are shown in FIG. 1 , but other configurations of cutouts in the plastic package are contemplated in the disclosed structures to allow infused contrast fluid to pass through the cutouts.

[0170] refer to Figure 16A , Figure 16B and Figure 16C, shows another embodiment of the proximal end of the outer catheter 36, which is specifically designed as a potential solution to prevent unwanted embolism situations when air inadvertently enters together with the fluid injected between the inner catheter 34 and the outer catheter 36. To prevent this, the flush lumen 290 is built into the pusher 134 via a flat subcutaneous injection tube. The Luer hub is coupled to the proximal end of the subcutaneous injection tube (pusher 134), as Figure 16C shown, so that the surgeon can inject fluid between the inner catheter and the outer catheter via the subcutaneous injection tube 134. When the fluid enters the outer catheter lumen 292 through the channel 290 in the subcutaneous injection tube 134, air bubbles are prevented from entering between the inner catheter and the outer catheter.

[0171] Further, referring to Figures 17A to 17C , in Figures 11A to 1 1E, Figures 12A to 12C , Figures 13A to 13B , Figures 14A to 14B and Figures 15A to 15D shows the interconnect unit 220 between the proximal couplers 130. The interconnect unit 220 includes a mating member 222 in the form of an annular ring 252 (also referred to herein as the middle locking ring), and the annular ring 252 is formed on the outer surface 224 of the inner catheter 34. The profile of the stainless - steel annular member 252 has a full - circular surface that permits a minimum reversible engagement / disengagement with the required split - ring feature of the outer catheter coupler 130. As Figure 17C shown, the ring 252 has a circular profile on the outer surface 302 for smooth locking / unlocking action. The inner surface 304 of the ring 252 is also a smooth structure that engages with the outer surface 224 of the inner catheter 34.

[0172] Figure 17A depicts the disengaged configuration of the inner catheter 34 relative to the outer catheter 36. Figure 17B represents the locked engagement configuration when the inner catheter 34 is received and locked inside the opening 210 at the proximal end of the sheath 120, such that the ring 252 is engaged in the snap - fit lock 306 formed by the distal continuous 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 is locked in the snap - fit lock 306, thereby engaging the inner catheter and the outer catheter for surgical operations as required by the surgery.

[0173] During longitudinal movement of the inner catheter 34 within the outer catheter 36, as the ring 252 passes through the proximal beveled split ring 312 and the middle 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, i.e., when the ring 252 is received between the rings 308 and 310, the ring arms of the beveled split ring 312 and the split ring 310 return to their original closed positions. The ring 252 trapped between the rings 308, 310 is snap-fit locked between the rings 308, 310, thereby preventing relative displacement between the inner catheter and the outer catheter.

[0174] Reference Figures 18A to 18B , details the structure shown in Figures 17A to 17C . A section (recess) 316 of the sheath 120 of the outer catheter 36 is shown not to be reinforced by the coil 170 and deflects when the middle rod locking ring 252 is inserted between the continuous distal ring 308 of the snap-fit lock 306 and the middle split ring 310. The deflected portion 316 of the sheath 120 between the rings 308 and 310 provides additional holding force to maintain the inner catheter 34 and the outer catheter 36 in a locked engagement.

[0175] The stainless-steel ring 252 can be attached to the outer surface 224 of the inner catheter rod 34 via an adhesive. The locking ring geometry (fully circular surface) allows for smooth reversible engagement / disengagement with the laser-cut features of the coupler 130 of the outer catheter. The distal ring 308 of the snap-fit lock 306 prevents further distal movement of the inner catheter 34, while the middle split ring 310 opens upon contact with the middle rod locking ring 252 and provides a tactile snap. The proximal beveled split ring 312 allows the funnel 211 to be opened to an inner diameter larger than the inner diameter of the remainder of the rod 120. The proximal beveled split ring 312 also allows for smooth passage of the middle rod locking ring 252.

[0176] Interference between the unreinforced rod recess 316 and the middle rod locking ring 252 provides retention of the inner catheter 34 to the outer catheter 36 until the user is ready to remove the inner catheter 34 from the outer catheter 36, thereby disengaging the snap-fit lock between the outer catheter 36 and the inner catheter 34. The force required to disengage the locking mechanism can be formulated from 0.1 pound to 2.0 pounds.

[0177] Reference Figures 19A to 19C , shows another alternative embodiment of the middle rod lock, which includes a square ring 320 (formed of a metal or polymer material). Different from the ring 252 shown in Figures 17A to 17C and Figure 18B as shown in Figure 19CAs shown, the ring 320 has a square cross-section 321. The square ring 320 is attached to the outer surface 224 of the inner conduit 34 by a heat-fused Pebax encapsulant 322. Alternatively, the square ring 320 can be glued to the outer surface 224 of the inner conduit. As Figure 19B shown, when the inner conduit is in the locked position, the square ring 320 snaps into a snap-fit lock 324 formed by the continuous ring 326 and the split ring 328, where the encapsulant 322 contacts the inner surface 152 of the sheath 120 and the ring 320 is positioned between the rings 326 and 328.

[0178] In another alternative embodiment, as Figures 20A to 20C shown, the central rod locking mechanism 220 and the mating member 222 form a cage structure 330 having two NiTi rings 332, 334 that are connected together by several (e.g., 4) NiTi forming wires 336. As Figure 20A shown, the cage 330 is attached to the outer surface 224 of the inner conduit 34 by gluing or by a heat-fused Pebax encapsulant 338. Each of the wires 336 has an arcuate extension 340 that is not encapsulated by the encapsulant 338, as Figure 20A and Figure 20B shown.

[0179] As Figure 20B shown, for the locking configuration, the cage structure 330 snaps into the coupler 130 of the outer conduit. The unencapsulated arcuate portion 340 of each wire 336 extends beyond the encapsulant 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 are engaged.

[0180] Further referring to Figure 21 , the proximal coupler 130 of the outer conduit 36 can include two locking slots 350, 352 formed by a ring 354 and a ring 356 connected by a connecting element 358.

[0181] Referring to Figures 17A to 17C , Figures 18A to 18B , Figures 19A to 19B , Figures 20A to 20C , and Figures 10A to 10G , Figures 11A to 11C , Figures 12A to 12B , Figures 13A to 13B , Figures 14A to 14B , Figures 15A to 15D and Figure 21, when the surgeon linearly displaces the inner member 34 within the inner channel 122 of the proximal coupler 130, the snap - fit rings 252, 320 or cage 330 enter the channel 122 between the ring arms of the proximal rings 240, 312, and the ring arms of the proximal rings 240, 312 are flexibly bent outward to permit forward movement of the inner catheter 34 (toward the distal end 162). When the snap - fit rings 252, 320 or cage 330 further pass through the central split rings 244, 262, 268, 310, 328 of the snap - fit lock, the ring arms of the beveled proximal rings return to their original positions, while the ring arms of the central split rings are flexibly bent outward to allow the rings 252, 320 of the cage 330 to reach the position between the distal continuous ring and the central split ring. After the rings / cage 252, 320, 330 are snap - fit between the rings of the snap - fit locking mechanism, the ring arms of the central split rings return to their original positions.

[0182] To disengage the inner member 34 from the outer member 36, the surgeon pulls the inner member 34 out of the inner channel of the proximal coupler 130. During removal of the snap - fit rings / cage 252, 320, 330 from the channel, the pulling action bends the ring arms of the central split rings outward to permit the snap - fit rings / cage 252, 320, 330 to pass between the ring arms of the central split rings, thereby releasing the inner catheter 34 from the proximal coupler 130 of the outer catheter 36.

[0183] Returning to Figure 3D , the inflation lumen distal rod 66 at the intermediate section 42 of the guiding catheter / pre - dilatation extension system 10 of the present disclosure can be manufactured with a braided reinforcement structure 260. The braided reinforcement member 260 forms a slightly flexible tube of the mating mechanism 222 of the interconnect unit 220 that is connected to the inner member 34. The RX (rapid exchange) port 94 for passing the guide wire 12 can be formed through the wall of the braided reinforcement inflation lumen distal rod 66.

[0184] The braided reinforcement structure 260 can be configured with a metal pattern or wire within the braided reinforcement inflation lumen distal rod 66 to prevent kinking, which will give the rod 66 longitudinal stiffness. The metal braid 260 can be embedded in the braided reinforcement rod 66 to increase its flexibility during the procedure for retracting the inner member 34 relative to the outer delivery sheath 120.

[0185] A flat - wire helical coil (e.g., made of a shape - memory alloy such as nitinol) having a wire thickness of about 1 mil to 3 mils can be embedded in the braid 260. The coil can be formed with very thin plastic coatings placed on its inner and outer surfaces, which facilitates reducing the wall thickness of the inflation lumen distal rod 66 to less than 7 mils and preferably to about 5 mils.

[0186] The principle of strengthening a tubular member by a catheter member coil reinforcement 170 in the form of a flat wire helical coil 262 or forming a tubular member from a flat wire helical coil can be applied in the guiding catheter extension / pre - dilation system 10 of the present disclosure to an outer delivery sheath 120 (such as Figure 7 , Figure 8B , Figures 9A to 9D , Figure 10A , Figure 11C , Figures 12B to 12C , Figures 13A to 13B , Figure 14B , Figures 15A to 15C , Figures 16A to 16B , Figures 17A to 17B , Figures 18A to 18B , Figure 19B , Figure 20B and Figure 21 ) as shown, and to a micro - catheter 46 (such as Figures 2A to 2B , Figure 5A , Figure 22 and Figures 24A to 24B as shown). In the outer delivery sheath 120 and / or the micro - catheter 46, such a flat wire helical coil can be embedded at a predetermined position along the length of its wall, for example, at the proximal end and / or the distal end.

[0187] Alternatively, the entire length of the outer delivery sheath 120 and / or the micro - catheter 46 can be formed from a flat wire helical coil. The pitch between the coils can be adjusted to provide an increasing flexibility gradient along the length of the tubular member (sheath 120 and / or micro - catheter 46) towards the distal end of the tubular member to facilitate atraumatic operation.

[0188] Referring to Figures 22A to 22B and Figures 23A to 23C , a monorail rapid - exchange (RX) design of the inner catheter 34' can be implemented instead of using a standard on - wire (OTW) guide wire lumen to allow the use of a short guide wire. In the Figure 22A and Figure 22B shown embodiment, which shows an isometric view of the coil - reinforced inner member rod 400 of the present disclosure and a side view of the coil - reinforced inner member rod 400 taken along line A - A, the distal section 40' of the inner member 34' includes a tapered element 402, and the tapered element 402 is 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, and the coil reinforcement structure 404 extends from the distal end 406 to the RX inlet port 94 shown in Figures 2A to 2C and Figures 3C to 3D . The distal end 406 is a tapered soft end, which, when the inner catheter 34' is inserted into the outer catheter 36 as required by the surgery, mates with the inner surface of the outer catheter 36 together with the tapered element 402.

[0189] The distal section 40' includes a concentric guide wire lumen 408 that communicates with an RX entry port at the proximal end of the inner catheter 34 (shown in Figures 2A to 2C and Figures 3C to 3D ).

[0190] As Figures 23A to 23C shown, the proximal end 41 of the monorail microcatheter embodiment shown in Figures 22A to 22B utilizes a cut hypodermic tube pusher 414. The proximal end 412 of the coil-reinforced inner member rod 416 and the hypodermic tube pusher 414 are encapsulated in a proximal outer sheath 418 that extends as a tube from (and includes) the coil-reinforced inner member rod 416 (serving as the guide wire lumen 408) and the hypodermic tube pusher 414 shown in Figures 22A to 22B along the proximal end 412 of the monorail microcatheter embodiment of the inner member 34'.

[0191] In Figures 23A to 23B the depicted embodiment features an RX guide wire "notch" terminal / entry 420 that is created by piercing the proximal outer sheath 418. Subsequently, the coil-reinforced inner member rod 416 is inserted into the proximal outer sheath 418 via the RX entry "notch" 420. The cut hypodermic tube 415 is further inserted into the proximal outer sheath 418 via the lumen 422 of the proximal outer sheath 418, and the polymer of the coil-reinforced inner member rod 416 and the proximal outer sheath 418 is fused together to connect the inner member rod 416 and the pusher 414 and thereby form the proximal end 412 of the monorail microcatheter inner member 34'.

[0192] For the convenience of the surgeon, the push / pull element 134 of the outer catheter 36 can be colored (colored coating), as Figure 11A shown, so as to have a distinguishing color to distinguish the push / pull element 134 of the outer catheter 36 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 the coronary guide wire for a delivery device or stent delivery system. Alternatively, the proximal outer sheath 418 of the push / pull element 414 can be colored to distinguish the color of the proximal outer sheath 418 of the push / pull element 414 from the colors of other elements in the system of the present disclosure.

[0193] Further referring to Figures 24A to 24B , an additional coil-reinforced balloon catheter embodiment 500 representative of the inner catheter that combines the enhanced rod characteristics of the microcatheter 46 with the enhanced rod characteristics of the dilation balloon 44 has the following properties:

[0194] a. The coil-reinforced member 502 provides additional kink resistance and pushability while still maintaining the flexibility for navigating tortuous vascular systems; and

[0195] b. The longer distal end 504 of the structure includes a low-profile, tapered soft tip to facilitate passage through narrow and tight lesions.

[0196] As Figures 24A to 24B shown, the distal section 504 of the structure 500 of the present disclosure includes an inner member shaft 500, which is reinforced by a coil reinforcement structure 506 that extends the length of the inner member shaft 500. The distal tapered element 508 is positioned on the inner member shaft 500 and extends between ends 510 and 512, in a surrounding relationship with the inner member shaft 500. The distal tapered soft tip 514 can be in the form of a microcatheter 46, which is positioned at the end of the coil-reinforced member 500.

[0197] Similar to the embodiment shown in Figures 22A to 22B , a balloon member 44 is positioned on the inner member shaft 500, and radiopaque markers 264 and 266 are positioned on the inner member shaft 500 within the balloon member 44. At the proximal end 516 of the balloon member 44, the balloon member 44 interferes with the outer end 164 of the proximal tapered element 178 of the outer member sheath 120. At the distal end 518, the balloon member 44 closely surrounds the shaft 500.

[0198] Returning to Figures 1 to 24B , in operation, to perform a cardiac procedure, and particularly a pre-dilation procedure, the proximal end of the coronary guidewire 12 enters the RX port 94 formed in the distal shaft 66 of the inflation lumen and extends through the inner channel (GW lumen 96) of the inner member 34 towards the outermost distal end 52 of the microcatheter 46 and beyond the outermost distal end 52 of the microcatheter 46. After this, the guiding catheter 14 is advanced into the vessel 16 of interest.

[0199] Subsequently, the outer delivery sheath 120 of the outer member 36, which is locked to the inner member 34 within the outer member, is first placed together with the microcatheter 46 in the inner channel 48 of the guiding catheter 14, and the inner member 34 and the outer member 36 are advanced as a single unit within the guiding catheter 14 towards the treatment site 22. The sheath 120 of the outer member and the inner member 34 can be displaced integrally by pushing the outer member pusher 134. This action causes the microcatheter 46 of the inner member 34 to slide along the GW 12 together with the outer member 36 until the microcatheter 46 of the inner member 34 and the outer member 36 extend beyond the distal end 50 of the guiding catheter 14 and reach the lesion site 92. At this step of the procedure, the balloon member 44 is in its deflated configuration.

[0200] The guide wire 12 that extends beyond the distal end 50 of the guide catheter 14 serves as a guide, and the microcatheter 46 (with the inflated balloon 44 attached to the distal tip 162) slides along this guide towards the treatment site 26.

[0201] Subsequently, the balloon member 44 (positioned at the treatment site 22) is inflated by a balloon inflation system 62 that is connected through an inflation lumen formed by an inflation lumen distal rod 66 and an inflation lumen subcutaneous tube 64 to an inflation hub 56, in order to compress the plaque and widen the blood passage inside the blood vessel 16.

[0202] Subsequently, once the lesion has been dilated, the balloon 44 is deflated, and the outer delivery sheath 120 can be advanced through the lesion 22 as an integral unit with the inner member 34 (in the engagement operating mode), and the inner member can subsequently be disengaged (unlocked) from the outer delivery sheath 120 and removed from the sheath 120.

[0203] Alternatively, the inner member 34 can be directly disengaged from and withdrawn from the sheath 120 after the lesion is dilated, while the outer member 36 is advanced through the lesion 22.

[0204] The sheath 120 can be left in place near the treatment site (directly after the lesion is dilated).

[0205] 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 inside the sheath 120. When in place, the stent (not shown) supporting the balloon can be expanded to open the stent. Subsequently, the outer delivery sheath 120 is removed, leaving the open stent in the blood vessel 16.

[0206] Reference Figure 25 To FIGS. 35C, the outer catheter (also referred to herein as the guide catheter extension subsystem) 36 can be configured with one or more holes 600. The outer catheter 36 can be formed with a cylindrical outer delivery sheath 120 that has an inner channel 122 extending along its interior. The outer delivery sheath 120 of the outer member 36 can be made of a flexible cylindrical tubular body. The outer delivery sheath 120 can include a proximal end 132 and a distal end 160, as Figure 29A shown. The outer catheter 36 can have any of the features of the outer catheter 36 described herein.

[0207] One or more holes 600 may facilitate fluid passage through the circulatory or lymphatic system. One or more holes 600 may assist with distal perfusion. One or more holes 600 may assist with the continuity of the flow rate during surgery. One or more holes 600 may assist with the consistency of blood flow during surgery. During a surgical procedure, perfusion must be maintained. Hemodynamic management may be crucial for the success of the surgical procedure.

[0208] One or more holes 600 may have several advantages. One or more holes 600 may reduce or eliminate the risk of myocardial ischemia in interventional treatments in the distal artery. Myocardial ischemia may occur when blood flow to the patient's heart is reduced. Due to partial blockage of the arteries of the heart, the myocardium cannot receive sufficient oxygen. One or more holes 600 may increase blood perfusion, allowing oxygenated blood to reach the myocardium while deploying an external catheter in the diseased coronary artery.

[0209] In some embodiments, the outer delivery sheath 120 of the outer member 36 may be modified to have one or more holes 600. One or more holes 600 may be used as perfusion holes. In some embodiments, one or more holes 600 may be located at or near the proximal end of the outer member 36. In some embodiments, one or more holes 600 may be located at or near the middle portion of the outer member 36. In some embodiments, one or more holes 600 may be located at or near the distal end of the outer member 36. In some embodiments, there may be segments that do not have perfusion holes, such as the segment between the proximal end and the distal end. The proximal segment of the outer member 36 that includes the proximal holes 600 may be seated in the coronary artery or possibly other arteries. The proximal segment of the outer member 36 may be affected by arterial blood pressure. This blood pressure may allow blood to rush into one or more proximal holes 600 and out of one or more distal holes 600. If no distal holes are provided, the blood pressure may allow blood to rush into one or more proximal holes 600 and out of the distal end 160 of the outer catheter 36.

[0210] Figure 25 is a perspective view of an embodiment of the outer catheter 36, which is configured with a plurality of holes 600 in the outer delivery sheath 120. One or more holes 600 may be laser cut. One or more holes 600 may be machined or drilled. One or more holes 600 may be formed in the sheath 120 during the manufacture of the sheath 120. One or more holes 600 may be formed in the sheath 120 after the manufacture of the sheath 120.

[0211] One or more holes 600 may be formed in the coiled or braided catheter structure of the sheath 120. The sheath 120 may be reinforced with a braid. The sheath 120 may be reinforced with a braid having coils. The sheath 120 may be reinforced with a structure embedded in a polymer matrix. One or more holes 600 may extend completely through the coiled or braided catheter structure of the sheath 120. One or more holes 600 may extend completely through the sheath 120 into the internal channel 122.

[0212] Two or more holes 600 may have the same diameter or cross-sectional dimension. Two or more holes 600 may have different diameters or cross-sectional dimensions. Figure 25 Three holes 600 having different diameters are shown. In some embodiments, the diameter of the holes 600 may be 25 microns, 50 microns, 75 microns, 100 microns, 125 microns, 150 microns, 175 microns, 200 microns, 225 microns, 250 microns, 275 microns, 300 microns, 325 microns, 350 microns, 375 microns, 400 microns, 425 microns, 450 microns, 475 microns, 500 microns, 600 microns, 700 microns, 800 microns, 900 microns, 1000 microns, 1100 microns, 1200 microns, between two of the foregoing values, or any range of two of the foregoing values.

[0213] Figure 26 is a perspective view of an embodiment of the outer catheter 36, which is configured with a plurality of holes 600 in the outer delivery sheath 120. In some embodiments, one or more holes 600 are aligned. In Figure 26 , a plurality of holes 600 are aligned. The plurality of holes 600 may include a first set of holes having a first larger diameter. The plurality of holes 600 may include a second set of holes having a second smaller diameter. The number of holes 600 in the first set and the second set may be the same. The number of holes 600 in the first set and the second set may be different. The sizes of the holes 600 in the first set and the second set may be the same. The sizes of the holes 600 in the first set and the second set may be different.

[0214] Figure 27FIG. 0 is a schematic view of an embodiment of an outer catheter 36 that is configured with a plurality of holes 600 in a proximal section within an outer delivery sheath 120. The outer catheter 36 can be disposed intravascularly. The proximal section of the outer catheter 36 can be within a proximal blood vessel. The plurality of holes 600 can be considered proximal perfusion holes. The plurality of holes 600 can receive blood flow from a blood vessel, such as an artery. The blood vessel can decrease in size along the length of the outer catheter 36. The size of the blood vessel can be decreased. The blood vessel can bifurcate. The vessel can be tortuous. The size of the blood vessel is decreased due to disease. The cross-section of the distal blood vessel can be smaller than the cross-section of the proximal blood vessel. Blood can flow out of the distal end 160 of the sheath 120. The direction of blood flow is shown by arrows. The plurality of holes 600 can be used as perfusion holes. The plurality of holes 600 can be drilled or laser cut into the proximal section of the sheath 120. The plurality of holes 600 can increase blood flow from the proximal blood vessel to the distal blood vessel. The plurality of holes 600 can reduce or eliminate the risk of myocardial ischemia by facilitating blood flow.

[0215] Figure 28 FIG. 4 is a schematic view of an embodiment of an outer catheter 36 that is configured with a plurality of holes 600 in both a proximal section and a distal section within an outer delivery sheath 120. The proximal section of the outer catheter 36 can be within a proximal blood vessel. The plurality of holes 600 can be considered proximal perfusion holes. The distal section of the outer catheter 36 can be within a distal blood vessel. The plurality of holes 600 can be considered distal perfusion holes. The plurality of proximal holes 600 can receive blood flow from a blood vessel, such as an artery. Blood can flow out of the plurality of distal holes 600 and the distal end 160 of the sheath 120. The direction of blood flow is shown by arrows. The plurality of proximal holes 600 can be circumferentially disposed. The plurality of proximal holes 600 can form one or more circumferential rings. The plurality of proximal holes 600 can be equally spaced around the sheath 120. The plurality of proximal holes 600 can be longitudinally disposed. The plurality of proximal holes 600 can form one or more longitudinal lines. The plurality of proximal holes 600 can be axially arranged. Each of the plurality of proximal holes 600 can have the same size. The plurality of proximal holes 600 can have different sizes.

[0216] The plurality of distal holes 600 can be circumferentially disposed. The plurality of distal holes 600 can form one or more circumferential rings. The plurality of distal holes 600 can be equally spaced around the sheath 120. The plurality of distal holes 600 can be longitudinally disposed. The plurality of distal holes 600 can form one or more longitudinal lines. The plurality of distal holes 600 can be axially arranged. Each of the plurality of distal holes 600 can have the same size. The plurality of distal holes 600 can have different sizes.

[0217] The plurality of proximal holes 600 and the plurality of distal holes 600 may have the same pattern or arrangement. The plurality of proximal holes 600 and the plurality of distal holes 600 may have different patterns or arrangements. Each of the plurality of proximal holes 600 and the plurality of distal holes 600 may have the same size or shape. The plurality of proximal holes 600 and the plurality of distal holes 600 may have different sizes or shapes. The plurality of proximal holes 600 and the plurality of distal holes 600 may have the same number of holes. The plurality of proximal holes 600 and the plurality of distal holes 600 may have different numbers of holes.

[0218] Figure 29A Figures 29D through 29D illustrate various examples of the placement of holes 600 in the sheath 120 of the outer catheter 36. As depicted in Figures 29A to 29C the sheath 120 may include a proximal section 610, a distal section 620, and an intermediate section 630. The intermediate section 630 may extend between the proximal section 610 and the distal section 620 and interconnect the proximal section 610 and the distal section 620. The proximal section 610 is located near the proximal end 132. The distal section 620 is located near the distal end 160.

[0219] Figure 29AAn embodiment of an outer catheter 36 having holes 600 on a sheath 120 is shown. The distal section 620 may include one or more holes, for example, one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The proximal section 610 may include one or more holes, for example, one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The distal section 620 may include one hole, in combination with the proximal section 610 including one hole. The distal section 620 may include two or more holes, in combination with the proximal section 610 including one hole. The distal section 620 may include one hole, in combination with the proximal section 610 including two or more holes. The distal section 620 may include two or more holes, in combination with the proximal section 610 including two or more holes. The ratio of the holes in the distal section 620 to the holes in the proximal section 610 may be 1:1, 1:2, 1:3, 1:4, 1:5, 2:1, 3:1, 4:1, 5:1, or any range of two or more values. The distal section 620 may include one or more holes 600 having a length of 0.25 cm, 0.5 cm, 0.75 cm, 1 cm, 1.25 cm, 1.5 cm, 1.75 cm, 2 cm, 2.25 cm, 2.5 cm, 2.75 cm, 3 cm, or any range of two of the foregoing values. The proximal section 610 may include one or more holes 600 having a length of 0.25 cm, 0.5 cm, 0.75 cm, 1 cm, 1.25 cm, 1.5 cm, 1.75 cm, 2 cm, 2.25 cm, 2.5 cm, 2.75 cm, 3 cm, or any range of two of the foregoing values. The intermediate section 630 may include a region 600 without holes.

[0220] Figure 29BAnother embodiment of the outer catheter 36 having a hole 600 in the sheath 120 is shown. The distal section 620 may include one or more holes, e.g., one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The distal end of the intermediate section 630 may include an area without holes. The intermediate section 630 and the proximal section 610 may include one or more holes, e.g., one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The proximal end of the proximal section 610 may include an area without holes. The proximal section 610 may include one or more holes, e.g., one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The intermediate section 630 may include one or more holes, e.g., one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The proximal section 610 may include one hole, in combination with the intermediate section 630 including one hole. The proximal section 610 may include two or more holes, in combination with the intermediate section 630 including one hole. The proximal section 610 may include one hole, in combination with the intermediate section 630 including two or more holes. The proximal section 610 may include two or more holes, in combination with the intermediate section 630 including two or more holes. The ratio of the holes of the proximal section 610 to the holes of the intermediate section 630 may be 1:1, 1:2, 1:3, 1:4, 1:5, 2:1, 3:1, 4:1, 5:1, or any range of two or more values.

[0221] The intermediate section 630 may include one hole, in combination with the distal section 620 including one hole. The intermediate section 630 may include two or more holes, in combination with the distal section 620 including one hole. The intermediate section 630 may include one hole, in combination with the distal section 620 including two or more holes. The intermediate section 630 may include two or more holes, in combination with the distal section 620 including two or more holes. The ratio of the holes of the intermediate section 630 to the holes of the distal section 620 may be 1:1, 1:2, 1:3, 1:4, 1:5, 2:1, 3:1, 4:1, 5:1, or any range of two or more values.

[0222] Figure 29CAnother embodiment of the external catheter 36 with a hole 600 in the sheath 120 is shown. The proximal section 610 may include one or more holes, for example, one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The intermediate section 630 may include one or more holes, for example, one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The distal section 620 may include one or more holes, for example, one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The proximal section 610 may include one or more holes in combination with the intermediate section 630 including one or more holes and the distal section 620 including one or more holes. The ratio of the holes in the proximal section 610 to the holes in the intermediate section 630 and the holes in the distal section 620 may be any suitable ratio. The holes 600 may be continuous along the length of the sheath 120 or a portion of the sheath 120.

[0223] The holes 600 in the sheath 120 may permit fluid flow. For example, the holes 600 in the sheath 120 may permit blood to flow in a direction generally from the proximal section 610 of the sheath 120 generally toward the distal section 620 of the sheath 120.

[0224] In one embodiment, the external catheter 36 in operation may be positioned within a patient such that the patient's arterial blood pressure causes blood to flow into the holes 600 of the proximal section 610 and out of the holes 600 of the distal section 620. In another embodiment, the external catheter 36 in operation may be positioned within a patient such that the patient's arterial blood pressure causes blood to flow into the holes 600 of the proximal section 610 and out of the holes 600 of the intermediate section 630. In yet another embodiment, the external catheter 36 in operation may be positioned within a patient such that the patient's arterial blood pressure causes blood to flow into the holes 600 of the intermediate section 630 and out of the holes 600 of the distal section 620. The external catheter 36 may be configured in any other arrangement to permit blood to flow in a direction generally from the proximal section 610 of the sheath 120 generally toward the distal section 620 of the sheath 120.

[0225] Figure 30 is a perspective view of an embodiment of the external catheter 36 configured with a plurality of circular holes 600 in the external delivery sheath 120. The holes 600 may have the same diameter or cross-sectional dimension. The holes 600 may be arranged along a line. The holes 600 may be located in any portion of the sheath 120 described herein.

[0226] Figures 31A to 31C Various examples of the size of the holes 600 are shown. Figure 31A An embodiment is shown in which the holes 600 have a generally uniform diameter. Figure 31BAn embodiment is shown in which the holes 600 have varying diameters. Two or more holes 600 can have the same diameter. Two or more holes can have different diameters. Figure 31C Another embodiment is shown in which the holes 600 have varying diameters. The diameter of the holes 600 can gradually decrease towards the distal end 160. The diameter of the holes 600 can gradually decrease towards the proximal end 132.

[0227] The diameter of the holes 600 can be sized such that blood can flow into or out of the holes 600. In one embodiment, the diameter or cross-sectional size of each hole 600 can be from 25 μm to 400 μm. In another embodiment, the diameter or cross-sectional size of each hole 600 can be between 100 μm and 200 μm. In yet another embodiment, the diameter or cross-sectional size of each hole 600 can be greater than 8 μm.

[0228] Figures 32A to 32C Various examples of the axial spacing between the holes 600 are shown. Figure 32A An embodiment is shown in which the holes 600 are axially spaced on the sheath 120 at a substantially uniform axial interval. The holes 600 can be equally spaced. Figure 32B Another embodiment is shown in which the holes 600 are axially spaced on the sheath 120 at a varying axial interval. The holes 600 can be unequally spaced. Figure 32C Yet another embodiment is shown in which the holes 600 are axially spaced on the sheath 120 at a varying axial interval.

[0229] The axial interval between axially adjacent holes 600 can have any length. In one embodiment, the axial interval between axially adjacent holes 600 can be from 1 mm to 10 mm. In another embodiment, the axial interval between axially adjacent holes 600 can be from 1 mm to 5 mm.

[0230] Figures 33A to 33C Various examples of the radial position of the holes 600 are shown. Figure 33A An embodiment is shown in which the holes 600 are positioned on the sheath 120 at a substantially uniform radial position. In one embodiment, the radial variation between axially adjacent holes can be approximately 0 degrees. The holes 600 can be coaxial. The holes 600 can be along the same circumferential position.

[0231] Figure 33BAnother embodiment is shown in which the holes 600 are positioned on the sheath 120 at varying radial positions. The radial variation between axially adjacent holes can be any suitable amount from about 0 degrees to 360 degrees. In one embodiment, the radial variation between axially adjacent holes can be from about 0 degrees to 180 degrees. In another embodiment, the radial variation between axially adjacent holes can be from about 0 degrees to 90 degrees. In yet another embodiment, the radial variation between axially adjacent holes can be from about 0 degrees to 45 degrees. The holes 600 can be circumferentially offset. The holes 600 can be arranged along a helix. The holes 600 can be arranged along a helical distribution. The helical distribution can reduce the likelihood of kinking of the outer catheter 36.

[0232] Figure 33C Yet another embodiment is shown in which there are holes 600 at multiple radial positions at a single axial position on the sheath 120. The holes 600 can be arranged in two circumferential positions. The holes 600 can be arranged in three circumferential positions. The holes 600 can be arranged in four circumferential positions. The holes 600 can be arranged in five circumferential positions. The holes 600 can be arranged in six circumferential positions. In one embodiment, a single axial position on the sheath 120 can include one or more holes, e.g., one hole, two holes, three holes, four holes, five holes, or any range of two of the foregoing values. The holes 600 at a single axial position on the sheath 120 can be positioned at any suitable radial position. In one embodiment, the holes 600 at a single axial position can be separated by about 180 degrees. In another embodiment, the holes 600 at a single axial position can be separated by about 120 degrees. In another embodiment, the holes 600 at a single axial position can be separated by about 90 degrees. In another embodiment, the holes 600 at a single axial position can be separated by about 72 degrees. In another embodiment, the holes 600 at a single axial position can be separated by about 60 degrees. Figure 30 Embodiment C shows an embodiment in which there are four holes 600 at a single axial position, with each of the four holes separated by about 90 degrees.

[0233] Figures 34A to 34C Embodiments of various non-circular holes 600 are shown. Figure 34A An embodiment is shown in which the hole 600 is elliptical. Figure 34B Another embodiment is shown in which the hole 600 is oblong. Figure 34C Another embodiment is shown in which the hole 600 is rectangular. For example, the shape and size of the hole 600 can be such that blood can flow into or out of the hole 600.

[0234] The hole 600 in the sheath 120 can be formed using any suitable method. In one embodiment, the hole 600 can be cut out of the sheath 120 using laser cutting techniques. In another embodiment, the hole 600 can be drilled from the sheath 120. In yet another embodiment, the hole 600 can be formed by the construction of the sheath 120.

[0235] Although the invention has been described in connection with its specific forms and embodiments, it will be understood that various modifications other than those discussed above can be made without departing from the spirit or scope of the invention as defined in the appended claims. For example, functionally equivalent elements may replace those specifically shown and described, certain features may be used independently of other features, and in some cases, elements, steps or procedures may be reversed or inserted at particular locations, all without departing from the spirit or scope of the invention as defined in the appended claims.

Claims

1. An intravascular delivery system, comprising: An outer member formed by a sheath that defines a sheath lumen having a proximal end and a distal end, wherein the sheath includes one or more holes; An inner member having an elongate body, wherein the inner member is configured to extend internally along the sheath lumen of the outer member.

2. The intravascular system according to claim 1, wherein, The one or more holes extend from an outer surface to the sheath lumen of the sheath.

3. The intravascular system according to claim 1, wherein, The sheath includes: A proximal section, a distal section, and an intermediate section that extends between the proximal section and the distal section of the sheath and interconnects the proximal section and the distal section of the sheath, wherein the one or more holes are located in the proximal section of the sheath.

4. The intravascular system according to claim 1, wherein, The sheath includes: A proximal section, a distal section, and an intermediate section that extends between the proximal section and the distal section of the sheath and interconnects the proximal section and the distal section of the sheath, wherein the one or more holes are located in the proximal section of the sheath and the one or more holes are located in the distal section of the sheath.

5. The intravascular system according to claim 1, wherein, The sheath includes: A proximal section, a distal section, and an intermediate section that extends between the proximal section and the distal section of the sheath and interconnects the proximal section and the distal section of the sheath, wherein the one or more holes are located in the intermediate section of the sheath and the one or more holes are located in the distal section of the sheath.

6. The intravascular system according to claim 1, wherein, The one or more holes are located to permit fluid to flow in a direction generally from the proximal section of the sheath substantially toward the distal section of the sheath.

7. The intravascular system according to claim 1, wherein, The one or more holes are circular.

8. The intravascular system according to claim 1, wherein, The one or more holes include a plurality of holes, wherein a single axial position on the sheath includes the plurality of holes.

9. The intravascular system according to claim 1, wherein, The one or more holes include a plurality of holes having the same diameter or cross-sectional dimension.

10. The intravascular system according to claim 1, wherein, The one or more holes include a plurality of holes arranged circumferentially.

11. The intravascular system according to claim 1, wherein, The one or more holes include a plurality of holes arranged longitudinally.

12. The intravascular system according to claim 1, wherein, The one or more holes include a plurality of holes in the proximal section of the sheath.

13. The intravascular system according to claim 1, wherein, The one or more holes include a plurality of holes in the distal section of the sheath.

14. The intravascular system according to claim 1, wherein, The sheath includes an intermediate section without any holes.

15. The intravascular system according to claim 1, wherein, The sheath includes a proximal section without any holes.

16. The intravascular system according to claim 1, wherein, The sheath includes a distal section without any holes.

17. The intravascular system according to claim 1, wherein, The sheath includes continuous holes.

18. The intravascular system according to claim 1, wherein, The one or more holes are configured to reduce or eliminate the risk of myocardial ischemia.

19. The intravascular system according to claim 1, wherein, The one or more holes promote perfusion.

20. The intravascular system according to claim 1, wherein, The tapered outer end of the outer member is an elastomeric tapered outer end.

21. The system according to claim 1, wherein, The sheath is reinforced along the length of the sheath.

22. The system according to claim 1, wherein, The inner member further includes a balloon member attached to the tapered distal portion of the inner member near a tapered delivery microcatheter.

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