Intravascular delivery system and method for percutaneous coronary intervention including perfusion - Patent Application 20070122997

Abstract

The guide catheter extension / pre-dilatation system includes an outer delivery sheath, an inner member extending within the sheath, and a 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-dilatation balloon member attached to the tapered distal tip proximal to the microcatheter. The outer delivery sheath and inner member are modified for operation of different engagement / disengagement mechanisms. The outer delivery sheath includes one or more holes configured to reduce or eliminate the risk of myocardial ischemia.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 18 / 046,699, filed October 14, 2022, the entire contents of which are incorporated herein by reference. U.S. Patent Application Nos. 16 / 132,878 and 15 / 899,603 are incorporated herein by reference. [Technical Field]

[0002] The present disclosure is directed to minimally invasive devices used for treatments within the human vasculature, such as the coronary arteries, and in particular to a delivery system for percutaneous coronary intervention that is particularly adapted for endovascular balloon angioplasty and coronary stent delivery, enhanced by a pre-dilation guide catheter extension function.

[0003] The present disclosure also relates to medical devices designed for the atraumatic, simple, and rapid delivery of various interventional devices, such as pre-dilation balloons or stents, and catheter exchanges within coronary arteries (or other blood vessels) within a patient's body to facilitate percutaneous revascularization.

[0004] The present disclosure further addresses an intravascular delivery system with a small, tapered, flexible distal tip that allows for practical, atraumatic crossing to the lesion site for treatment, as well as exceptional deliverability of the interventional device that is superior to that of conventional balloon angioplasty catheters.

[0005] The present disclosure also relates to an intravascular guide catheter extension / pre-dilator system that uses an inner member (an interventional device delivery catheter subsystem) positioned in place within an outer member (an outer delivery catheter subsystem), the inner member being formed with a distal coil-reinforced tapered section that meets the slightly tapered distal end of the outer member. These are dimensioned to create a low-profile and substantially "seamless" transition at the junction between the distal end 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 atraumatic and smooth passage of the inner and outer members as a single unit along the diseased vessel.

[0006] Additionally, the present disclosure relates to an intravascular guide catheter extension / pre-dilator system comprised of an outer catheter (member) and an inner catheter (member) displaceable inside and along the outer catheter, wherein the distal tapered soft tip of the outer catheter is formed as an expandable, flexible, low-durometer, elastic member having an inner diameter in a contracted configuration that is smaller than the outer diameter of the distal portion of the inner catheter at the engagement region with the outer catheter. This arrangement achieves reversible elastic engagement between the outer and inner catheters at their distal ends, thereby ensuring that the enlarged distal end of the outer catheter returns to its reduced outer diameter when the inner catheter is detached from the outer catheter, and reducing (or eliminating) a "fish mouth" at the distal junction of the outer and inner members as the system is advanced around a bend in a blood vessel.

[0007] The present disclosure further relates to an intravascular guide catheter extension / pre-dilatation system configured with an outer catheter and an inner catheter that are displaceable relative to one another, wherein the proximal end of the outer catheter has an inlet configuration that provides improved reinforcement for contrast injection fluid, improved mid-shaft stent entry, prevention of stent embolization, increased flexibility, and improved flow rate.

[0008] Additionally, the present disclosure relates to an intravascular guide catheter extension / pre-dilatation system designed with a midshaft interconnection (locking) mechanism that can be activated / deactivated by a physician to (1) controllably engage the inner and outer members for unified movement within the guide catheter along a guidewire, or (2) disengage the inner and outer catheters for retraction of the inner catheter from the outer member (catheter) as required by the endovascular procedure. The inner member may carry an interventional device (e.g., a pre-dilatation 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 midshaft reversible lock also prevents any forward movement of the inner member relative to the outer member during advancement or withdrawal of the system, ensuring that the position of the distal "seamless" transition between the inner and outer catheters remains essentially fixed in place axially during movement of the system.

[0009] Additionally, the present disclosure relates to an intravascular guide catheter extension / pre-dilatation system configured with a tapered coil-reinforced shaft at its distal end for mounting and carrying a balloon member thereon, providing "seamless" entry and smooth delivery of the balloon member, integral with the coil-reinforced delivery sheath of the outer catheter, to a desired treatment site.

[0010] The present disclosure further addresses an intravascular guide catheter extension / pre-dilatation system featuring a monorail microcatheter embodiment with rapid exchange (RX) capability for use with short guidewires, wherein the distal tapered flexible end of the inner catheter is comprised of a coil-reinforced microcatheter that provides additional kink resistance and "pushability" while still maintaining flexibility for navigating tortuous vasculature.

[0011] Additionally, the present disclosure relates to an intravascular guide catheter having an outer catheter formed by a sheath that defines one or more side holes that allow for distal perfusion. [Background technology]

[0012] Coronary artery occlusive disease or other diseases in the peripheral vasculature are often treated with balloon angioplasty and / or stent placement. Advancing a revascularization device, such as an intravascular balloon or stent delivery system, to the treatment site can be difficult for physicians when the vessel is tortuous and / or calcified.

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

[0014] Treating a blocked coronary artery with a stent follows essentially the same steps as other angioplasty procedures, but with an important difference: A compressed stent mounted on a balloon significantly reduces the balloon's flexibility, impairing its smooth advancement through the coronary artery. This can make it difficult or impossible to deliver the stent to the treatment site, and there is a risk of dislodgement of the undeployed stent from its delivery balloon.

[0015] Intravascular imaging can be used to assess the thickness and hardness (calcification) of the lesion, which affects the deliverability of a stent. Cardiologists use this information to decide whether to treat the lesion with a stent, and if so, what type and size of stent to use. Both bare metal and drug-eluting stents are most often sold as units, with the stent in its collapsed (pre-expanded) form mounted on the outside of a balloon catheter.

[0016] Physicians may perform "direct stenting," in which a stent is threaded through the blood vessel to the lesion and expanded. However, to facilitate stent delivery in more difficult lesions, it is common to predilate the occlusion before delivering the stent.

[0017] Pre-dilation is accomplished by penetrating the lesion with a conventional balloon catheter and dilating it to increase the diameter of the lesion. A balloon catheter is a type of "flexible" catheter with an inflatable balloon at its tip that is used during catheterization procedures to enlarge narrow openings or passageways in the body. Following pre-dilation, the pre-dilation balloon is removed, and a stent catheter is threaded through the vessel to the lesion, expanded, and left as a permanent implant to "scaffold" the vessel open at the lesion site.

[0018] Balloon catheters used in angioplasty have either an over-the-wire (OTW) or rapid-exchange (RX) design. The balloon catheter slides into position over a guidewire, which can be loaded onto the balloon catheter via the hub (in over-the-wire modifications) or via the RX port (for rapid-exchange modifications of the balloon catheter). In over-the-wire balloon catheters, a concentric lumen for passing the guidewire extends within the catheter from the proximal hub to the balloon, while in rapid-exchange (RX) balloon catheters, a lumen for passing the guidewire extends from the RX port in the catheter to the balloon, allowing for passage of the guidewire.

[0019] Revascularization devices typically use a guiding (or guide) catheter to deliver such devices to the treatment site. The use of a guide catheter alone to "back up" the advancement of a revascularization device into a coronary artery can be limiting and difficult, especially when a stent is placed using a radial access guiding catheter.

[0020] To facilitate delivery of revascularization devices to the target site, guide catheter extension systems have been designed and used during cardiac procedures.

[0021] For example, guide extension systems such as the "Guideliner™" manufactured by Teleflex are described in U.S. Patent No. 8,292,850 to Root et al., which describes a coaxial guide catheter passing through the lumen of a guide catheter for use with an interventional cardiac device insertable into a branch artery branching off a main artery.

[0022] The Root coaxial guide catheter extends through the lumen of the guide catheter beyond its distal end and is inserted into the branch artery. Root uses a guide extension supported by a tapered inner catheter. The purpose of the inner catheter is to provide an atraumatic tip to avoid vessel injury while advancing the guide extension into the proximal portion of the coronary vessel to provide additional "backup" support for the delivery of a stent or balloon.

[0023] Another guide extension system, such as the "Guidezilla™," is designed and manufactured by Boston Scientific. This guide extension system is described in U.S. Pat. No. 9,764,118, written by Anderson et al. The Anderson guide extension system uses a push 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 that provides a smooth transition between the proximal and distal portions. A distal tubular member is attached to the push member and has an outer diameter larger than the outer diameter of the push member.

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

[0025] The Guideliner™ and Guidezilla™ systems, as well as the Ho system, support the concept of advancing a guide extension system through a guide catheter and partially down a coronary artery to achieve additional “backup” support for delivering a balloon dilatation catheter and / or stent delivery catheter to the intended treatment site.

[0026] The function of these guide extensions is to allow a closer approach to the lesion to provide additional support when crossing the lesion to be treated with an interventional device. However, despite the additional support, the lesion to be treated may still be difficult or nearly impossible to traverse with a pre-dilation balloon catheter or stent delivery system due to fibrosis, calcification, previous stent struts within the lumen, and / or angulation at the lesion site.

[0027] One limitation of currently used guide extension devices is the use of a relatively blunt, large-diameter cylindrical distal end. The relatively high-profile distal edge often limits the deliverability of the guide extension, allowing advancement only to the proximal or mid-portion of the coronary artery to be treated. Even after balloon predilation of the lesion, it is very rare, if ever, for the guide extension to be delivered to the actual lesion to be treated with angioplasty or stenting. These "blunt-end" tubular guide extension devices can fail relatively frequently, potentially resulting in serious dissection complications. Published data demonstrate that "blunt-end" tubular guide extension systems can fail in up to 20% of cases and cause serious coronary artery dissections in approximately 3% of cases.

[0028] U.S. Patent Application Publication No. 2011 / 0301502, written by Gill, describes a catheter with a longitudinal extension that allows the positioning device to be smaller in diameter than the stent delivery system. However, the Gill device does not envision an inner catheter to allow for easy and atraumatic crossing of the lesion to be treated. The Gill system simply acts as a covering for the stent delivery system, which can be removed after advancement of the stent delivery system due to the longitudinal extension.

[0029] While the concept of an inner tapered member of a guide extension catheter is seen in the Root device, prior art systems use a very short taper and do not envision the taper as an elongated, integrated member of the overall system, nor do they envision the ability to attach a pre-dilation balloon to a tapered delivery microcatheter that is delivered to the target treatment area. Additionally, the prior art fails to envision a substantially "flush" interface between the inner catheter and the outer guide extension within the vessel, or that the inner and outer catheter members are reversibly mated or locked together to facilitate easy movement of the entire system as one integrated device. Neither the Root nor other prior art systems describe, predict, or envision a balloon (and / or stent) delivery system with a very low-profile, elongated tip, which would be useful in achieving coaxial delivery of the guide catheter extension / balloon system to and beyond the lesion of interest. Such an embodiment has never been commercially available, and the description of the tapered tip inner device is intended only as a mechanism for proximal delivery of the blunt tip of a guide catheter extension from a guide catheter, and never as a mechanism for delivering a balloon (and / or stent) to and beyond a target treatment area within a blood vessel, nor is the unitary nature and "flush" interconnection of the inner and outer members intended to allow the outer delivery "sheath" member to cross the target lesion.

[0030] Thus, devices and methods that enable delivery of the distal portion of a tubular guide extension system to, or ideally beyond, the lesion to be treated have significant advantages over conventional guide extension devices such as "Guideliner™" (Teleflex) or "Guidezilla™" (Boston Scientific).

[0031] None of the conventional balloon catheters (over-the-wire or rapid-exchange) are integrated with an outer delivery sheath, and none of them use a tapered delivery microcatheter with an interventional device (e.g., a balloon, stent, etc.) secured to the distal end of the catheter for atraumatically advancing the catheter through the blood vessel to and beyond the lesion site. Additionally, none of the conventional balloon catheters are interconnected with the outer delivery sheath (guide catheter extension subsystem) via an interconnection mechanism that is actuated to allow for unitary movement of the conventional balloon catheter and outer delivery sheath as a single unit, and that is deactuated to allow for retraction of the balloon catheter from the outer delivery sheath while preventing forward displacement of the balloon catheter relative to the outer delivery sheath.

[0032] It would be highly desirable and efficient to provide an intravascular delivery system that can deliver an interventional device (e.g., a pre-dilatation balloon) along with a guide catheter extension subsystem (such as an outer delivery sheath) to and across a lesion in a substantially atraumatic and convenient manner.

[0033] It would also be highly desirable to provide an intravascular delivery system having outer and inner catheters both featuring reinforced distal ends with compact, tapered distal tip profiles with "seamless" distal contact points to ensure atraumatic crossing of the system across the lesion for treatment.

[0034] Additionally, it is desirable to facilitate percutaneous revascularization procedures by using a balloon attached to the coil-reinforced tapered distal tip of an inner balloon catheter fitted within the outer delivery sheath of an outer catheter, where the inner balloon catheter is fitted with a distal elongated tapered coil-reinforced microcatheter at the tapered distal tip for carrying an interventional device (pre-dilatation balloon, and / or stent) to and past the lesion to be treated. This represents a substantial improvement over conventional guide catheter extension and pre-dilatation systems. Summary of the Invention [Problem to be solved by the invention]

[0035] It is therefore an object of the present disclosure to provide a medical device for intravascular application that can deliver an interventional device (such as a balloon or stent) to and across a coronary artery occlusion lesion in an efficient and minimally traumatic manner.

[0036] Another object of the present disclosure is to provide an intravascular delivery system that uses a coaxial, highly flexible delivery catheter arrangement with outer and inner catheters that abut at their distal ends in a "seamless" fashion with a compact profile that is useful for achieving "crossability" of a pre-dilatation balloon (or other interventional device) and improves efficient and safe distal delivery of guide extension devices.

[0037] A further object of the present disclosure is to use a highly flexible, coil-reinforced, distally tapered, elongated microcatheter tip to deliver a pre-dilation balloon (or another interventional device) to and / or across a target lesion in a diseased human coronary artery being treated with angioplasty (or stenting).

[0038] It is a further object of the present disclosure to provide a guide catheter extension / pre-dilatation system that uses an outer catheter (outer delivery sheath subsystem) and an inner catheter (interventional device delivery subsystem) that fits within and is interchangeably connected to the outer sheath of the outer catheter, which can be delivered either to or beyond the lesion area for treatment within a blood vessel, wherein the inner catheter has a delivery tapered microcatheter at its distal end, and a pre-dilatation balloon member (or another interventional device) is attached to the delivery tapered microcatheter and slides along the guidewire in a substantially atraumatic manner.

[0039] It is a further object of the present disclosure to provide a guide catheter extension / pre-dilatation system comprising a guide catheter extension subsystem (outer member) integrated with a pre-dilatation balloon (or another interventional device) subsystem (inner member), where the outer and inner members are coupled to one another (via a locking mechanism) and displaced together (as a "whole system") along a guidewire to the lesion site. After the pre-dilatation procedure, the guide catheter extension subsystem (configured with an outer delivery sheath) can be unlocked from the inner member and advanced beyond the lesion as desired. The inner member (interventional device delivery subsystem) can then be withdrawn. If necessary for the surgical procedure, the outer delivery sheath of the outer member may remain within the guide catheter to enhance the delivery of a stent (or other interventional device) to the lesion site inside the outer delivery sheath. The outer delivery sheath may then be withdrawn after the stent (or other interventional device) has been delivered to the lesion and deployed for ultimate treatment.

[0040] It is a further object of the present disclosure to provide a guide catheter extension / pre-dilatation system equipped with a "locking mechanism" operably coupled between the inner member and outer member (outer sheath) to provide integral passage of both the inner and outer members as a single unit to provide convenient and safe delivery of the pre-dilatation balloon and outer sheath to and beyond the treatment site.

[0041] It is a further object of the present disclosure to provide a guide extension system configured with a pre-dilation balloon (or other interventional device) delivery catheter that is atraumatic and deliverable to a treatment site within the vasculature to expedite cardiac procedures, achieving easy passage of the balloon (or other interventional device) and guide extension system, allowing percutaneous coronary interventions to be performed with lower radiation exposure than achieved with conventional systems, with the added advantage of substantially no risk of stent embolization or drug loss (due to drug-eluting stents) from the stent delivery system.

[0042] It is a further object of the present disclosure to provide an intravascular guide catheter extension / pre-dilatation system comprised of coaxial inner and outer catheters that are displaceable relative to one another and strengthened by coil reinforcement along their lengths, yet are flexible enough to achieve improved contrast injection flow rates and embolization prevention, wherein the tapered distal end of the outer catheter can be elastically stretched to create strong contact with the distal portion of the inner catheter and form a nearly flush (smooth) outer surface at the point of contact between the inner and outer catheters.

[0043] Another object of the present disclosure is to provide an outer guide extension catheter having side holes to enable distal coronary perfusion during delivery to distal vessels, tortuous vessels, and / or diseased vessels proximal to the target lesion site. Yet another object of the present disclosure is to provide an outer guide extension catheter having side holes to enable distal coronary perfusion after withdrawal of the inner catheter. The one or more holes can increase distal perfusion, thereby allowing oxygenated blood to flow while the outer catheter is deployed within the vessel. [Means for solving the problem]

[0044] The present system and method address an intravascular delivery system configured for controllable displacement along a guidewire within a blood vessel of a target. The system is formed with a proximal section, a distal section, and a mid-section portion located between the proximal and mid-sections. The system includes an outer member formed by a flexible, substantially cylindrically contoured, elongated outer delivery sheath defining a sheath lumen having a proximal end and a distal end. The outer delivery sheath extends between the mid-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 extending cylindrically between the distal and proximal edges of the tapered outer tip. The wall of the tapered outer tip has an inner diameter and an outer diameter. The inner and outer diameters of the wall of the tapered outer tip gradually decrease in dimension from the proximal to the distal edge of the tapered outer tip. The proximal (wire or hypotube) element (push or pull) connected to the tubular structure of the outer member may be low profile and "flexible" (as opposed to "rigid") to allow for improved fit within the guide catheter and a lower profile than the rigid "push" elements in conventional guide extension catheters (per Root). This is made possible due to the "pushability" of the "whole system" achieved via the locked, integral connection between the outer catheter (with its hypotube push / pull element) and the inner catheter (guide extension tube).

[0045] The system further includes an inner member (inner catheter) having an elongate body defining an internal channel extending along a 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 inner member elongate body has an outer diameter and a tapered distal portion configured with a tapered delivery catheter having an elongate body of a predetermined length. The inner member tapered delivery catheter is displaceable beyond the distal end of the outer sheath. Importantly, the inner diameter of the wall of the tapered outer tip of the outer member is smaller than the outer diameter of the tapered distal portion of the inner member in the region where the two elements form a distal junction.

[0046] An interconnection mechanism is operatively coupled between the inner and outer members and controllably actuated to operate the guide catheter extension / pre-dilatation subsystem in an engaged or disengaged mode of operation. In the engaged mode of operation, the inner and outer members of the guide catheter extension subsystem are engaged for controllable common displacement along the guidewire. This also allows for improved "pushability" of the system (where the outer member is connected and locked to the inner member) even when the connected pusher (push / pull element) of the outer member has a small profile and is flexible (flexible or more flexible than the outer tubular sheath of the outer catheter). In the disengaged mode of operation, the inner and outer members are disengaged to retract the inner member from the outer member after pre-dilatation treatment, or stent delivery.

[0047] The distal portion of the inner member abuts at its outer surface against the inner surface of the tapered outer tip of the sheath lumen, with the dimensional transition between the outer diameter of the outer tip of the sheath lumen and the outer diameter of the distal tip of the inner member forming a substantially flush tangent transition therebetween.

[0048] The tapered outer tip of the outer member has a resiliently expandable configuration. At its proximal end (also referred to herein as the mid-shaft portion of the outer member), the outer sheath is configured with an entrance opening that exceeds the circumference of the tubular body of the outer sheath in its circumference. In some embodiments, the entrance opening at the proximal end of the outer sheath is funnel-shaped.

[0049] The outer sheath is preferably reinforced along its length. The outer member includes a distal soft tip encapsulating material at its distal end that surrounds the reinforced sheath of the outer member. The distal soft tip encapsulating material is a flexible, low durometer, resilient material having a gradient durometer that increases from the distal end to the proximal end of the sheath.

[0050] The outer member also includes a distal lubricious liner sandwiched between the outer surface of the outer sheath and the inner surface of the distal soft tip encapsulant.

[0051] The delivery catheter is preferably a microcatheter, which is formed from a flexible material and may have differential flexibility along its length, with the flexibility of the microcatheter increasing towards its distal end.

[0052] A balloon member is attached to the tapered distal portion of the inner member adjacent to the tapered delivery microcatheter. An inflation lumen extends within the inner member between the balloon member at the proximal and distal sections to provide a fluid passageway between the external balloon inflation system and the balloon member. The balloon member may be in an inflated or deflated configuration. In the deflated configuration, the balloon member is displaced within the vessel. After being positioned at least in alignment with the treatment site for the pre-dilatation procedure, the balloon member is controllably deformed to the inflated configuration.

[0053] The elongate body of the inner member and the microcatheter are coil reinforced along their lengths.

[0054] An outer catheter pusher / puller element, configured with a flattened portion at its distal end, is secured to the proximal end of the outer catheter's outer sheath. Preferably, the outer member pusher / puller is configured with a channel extending along its length in fluid communication with the sheath lumen to prevent embolization. This proximal (pushing and pulling) element, connected to the outer catheter's outer sheath tubular structure, may be low-profile and "flexible" (as opposed to "rigid") to allow for better fit within the guide catheter and a lower profile than the rigid "pushing" elements in conventional guide extension catheters (such as the Root).

[0055] The interconnection mechanism may include a snap-fit ​​locking mechanism including a proximal coupler disposed at the proximal end of the sheath of the outer member (catheter) and a cooperating element disposed on the outer surface of the elongated body of the inner member (catheter). The proximal coupler may include a distal solid ring and an intermediate split ring disposed a predetermined distance from the solid ring, and the cooperating element may include a member selected from the group including an intermediate shift lock ring, a square annular ring, a snap-fit ​​cage, and other similar elements. The cooperating element is secured to the outer surface of the elongated body of the inner member. When the cooperating element is snap-fit ​​engaged and locked between the distal solid ring and the intermediate split 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 may be made from a memory metal (e.g., nitinol, etc.) to prevent deformation during antegrade or retrograde movement of the outer member and to prevent deformation of the midshaft coupler (also referred to herein as the proximal coupler) while a stent or other device is passed through the midshaft portion of the outer catheter.

[0056] The proximal coupler further includes a proximal angled split ring at its proximal end, which reinforces the funnel like proximal inlet of the outer member and prevents damage or permanent deformation of the funnel-shaped proximal inlet caused by displacement of the inner member or stent delivery system within the funnel inlet. The coupler and midshaft inlet may have an inlet opening (or "port") having a circumference greater than the circumference of the flexible tubular outer sheath structure of the outer member.

[0057] The intravascular system further includes a guidewire advanceable within the target vessel at least to the treatment site, and the guide catheter extension subsystem is configured for controllable displacement along the guidewire. In one embodiment of the system, an elastic outer jacket surrounds the inner member at least at its proximal end and the inner member pusher / puller along at least its distal end. The proximal end of the inner member is connected to the pusher / puller by fusing the elastic outer jacket to the length of the proximal end of the inner member and snugly supporting the inner member pusher / puller within the elastic outer jacket.

[0058] The push / pull element of the outer catheter (or its outer jacket) may be color coated to have a distinctive color to distinguish it from the push / pull element of the inner catheter and from the usual gray or silver color of the coronary guidewire. Alternatively, the elastic outer jacket of the inner member may be color coated to distinguish the inner member pusher / puller from the color of other elements in the system for the convenience of the surgeon.

[0059] These and other objects and advantages of the present disclosure will become apparent to those skilled in the art from a reading of the detailed description of the present disclosure in conjunction with the patent drawings. [Brief explanation of the drawings]

[0060] [Figure 1] FIG. 1 is a schematic diagram of the present guide catheter extension / pre-dilatation system advanced to a target site within a coronary artery.

[0061] [Figure 2A] FIG. 1 is a schematic diagram illustrating the guide catheter extension / pre-dilatation system, showing the assembled inner and outer catheters. [Figure 2B] FIG. 1 is a diagram illustrating the guide catheter extension / pre-dilatation system in detail, showing the inner catheter. [Figure 2C] FIG. 1 is a diagram illustrating the guide catheter extension / pre-dilatation system in schematic form, detailing the mid-section of the system.

[0062] [Figure 3A] FIG. 1 is a longitudinal cross-sectional view of an inflation lumen hypotube interconnected with an inflation lumen distal shaft within the inner catheter, depicting the mid-section of the inner catheter of the present invention. [Figure 3B] FIG. 10 is a representation of the mid-section of the inner catheter of the present invention, detailing a longitudinal cross-section of the skived portion of the inflation lumen hypotube. [Figure 3C] FIG. 1 is a longitudinal cross-sectional view of the inner catheter showing the mid-section of the inner catheter of the present invention, showing the RX guidewire (GW) port formed in the inflation lumen distal shaft. [Figure 3D] 3D is an isometric view of the RX port portion of the inner catheter shown in FIG. 3C, showing the mid-section of the inner catheter of the present invention. FIG.

[0063] [Figure 4] FIG. 10 is a longitudinal cross-sectional view of the inner catheter detailing the distal end of the inflation hypotube at the junction with the inflation lumen distal shaft.

[0064] [Figure 5A] FIG. 10 is a diagram of the distal section of the system showing an inflated balloon member. [Figure 5B] FIG. 10 shows the distal section of the system, showing the deflated balloon member. [Figure 5C]FIG. 1 shows the distal section of the system, detailing the inflation lumen / balloon junction.

[0065] [Figure 6A] FIG. 10 is a longitudinal cross-sectional view of the distal section of the inner catheter detailing the 3 mm distal and proximal taper of the balloon. [Figure 6B] FIG. 10 is a longitudinal cross-sectional view of the distal section of the inner catheter detailing the 6 mm distal and proximal taper of the balloon.

[0066] [Figure 7] FIG. 1 shows the distal tip of the outer catheter.

[0067] [Figure 8A] FIG. 11 is a diagram detailing the contact point between the inner and outer catheters at their distal ends, showing the tapered distal end of the inner catheter. [Figure 8B] FIG. 11 is a detailed view of the junction between the inner and outer catheters at their distal ends, showing a somewhat enlarged view of the connection point between the inner and outer catheters.

[0068] [Figure 9A] 10A-10C depict an alternative embodiment of an elastically expandable distal tip of an outer catheter configured with an expandable split ring. [Figure 9B] 10A-10D depict an alternative embodiment of an expandable tip scaffold. [Figure 9C] 10A-10C depict alternative embodiments of the slit. [Figure 9D] 10A-10C depict alternative embodiments of the slit.

[0069] [Figure 10A] FIG. 10 is a side view of an alternative embodiment of the proximal portion of the outer catheter. [Figure 10B] FIG. 10 is a side view of an alternative embodiment of the proximal portion of the outer catheter. [Figure 10C]FIG. 10 is an isometric view of an alternative embodiment of the proximal portion of the outer catheter. [Figure 10D] FIG. 10 is a side view of an alternative embodiment of the proximal portion of the outer catheter. [Figure 10E] FIG. 10 is an isometric view of an alternative embodiment of the proximal portion of the outer catheter. [Figure 10F] FIG. 10 is a side view of an alternative embodiment of the proximal portion of the outer catheter. [Figure 10G] FIG. 10 is an isometric view of an alternative embodiment of the proximal portion of the outer catheter.

[0070] [Figure 11A] FIG. 10 is an isometric view of a flattened hypotube pusher showing details of the coupler design at the proximal end of the outer catheter. [Figure 11B] FIG. 10 is an isometric view of the proximal end of the outer catheter showing details of the coupler design at the proximal end of the outer catheter. [Figure 11C] FIG. 10 shows a detailed design of the coupler at the proximal end of the outer catheter. FIG. 11 is a side view of the coupler at the proximal end of the outer catheter, featuring a snap-fit ​​locking mechanism.

[0071] [Figure 12A] FIG. 10 illustrates an alternative embodiment of the proximal portion of the outer catheter, showing an isometric view of the proximal coupler. [Figure 12B] FIG. 10 illustrates an alternative embodiment of the proximal portion of the outer catheter, showing an isometric view of an encapsulated proximal coupler. [Figure 12C] FIG. 10 illustrates an alternative embodiment of the proximal portion of the outer catheter, showing a side view of an encapsulated proximal coupler.

[0072] [Figure 13A] FIG. 10 is an isometric view of yet another embodiment of a proximal coupler at the proximal end of the outer catheter. [Figure 13B] FIG. 10 is a side view of yet another embodiment of a proximal coupler at the proximal end of the outer catheter.

[0073] [Figure 14A] 10A-10C illustrate an embodiment of a weld ring at the proximal inlet of the outer catheter, showing a weld ring coupler. [Figure 14B] 10A-10C show an embodiment of a weld ring at the proximal entrance of the outer catheter, illustrating an encapsulated weld ring coupler.

[0074] [Figure 15A] FIG. 10 is a side view of an additional alternative embodiment of the proximal coupler of the outer catheter, with a circularly contoured funnel fenestration. [Figure 15B] FIG. 10 is an isometric view of a circularly contoured funnel fenestration of an additional alternative embodiment of the proximal coupler of the outer catheter. [Figure 15C] FIG. 10 is a side view of a triangular funnel fenestration of an additional alternative embodiment of the proximal coupler of the outer catheter. [Figure 15D] FIG. 10 is an isometric view of a triangular funnel fenestration;

[0075] [Figure 16A] FIG. 10 is an isometric view of the proximal coupler of the outer catheter coupled with the pusher, illustrating the hypotube pusher single lumen concept. [Figure 16B] FIG. 16B is a cross-sectional isometric view of FIG. 16A showing the flow path within the pusher, illustrating the hypotube pusher single lumen concept. [Figure 16C] FIG. 10 illustrates the hypotube pusher single lumen concept and the procedure for injecting flushing fluid between the inner and outer catheters.

[0076] [Figure 17] 17A and 17B illustrate the intermediate shaft annular rounded ring locking mechanism of the present invention, where FIG. 17A illustrates the "lock disengagement" mode of operation, FIG. 17B illustrates the "lock engage" mode of operation, and FIG. 17C illustrates the annular rounded ring in the locking mechanism of the present invention.

[0077] [Figure 18A] 17A-17B show the present annular rounded circular ring locking mechanism and a proximal coupler configured with a locking pocket for engaging with the annular rounded circular ring (FIG. 17C). [Figure 18B] 17A-17B are longitudinal cross-sectional views of the inner and outer catheters locked together, showing the present annular rounded circular ring locking mechanism.

[0078] [Figure 19] 19A and 19B show an alternative embodiment of a locking mechanism featuring a midshaft "square" annular ring; FIG. 19A shows an inner catheter equipped with a ring-shaped locking mechanism; FIG. 19B shows the ring of the inner catheter snapped onto the proximal coupler of the outer catheter; and FIG. 19C shows a cross-sectional view of the square annular ring.

[0079] [Figure 20A] FIG. 10 illustrates an alternative "snap-fit ​​cage" locking mechanism, showing an inner catheter with a welded cage lock. [Figure 20B] FIG. 10 illustrates an alternative "snap-fit ​​cage" locking mechanism, showing a welded cage lock on the inner catheter snapped onto the proximal coupler of the outer catheter. [Figure 20C] FIG. 10 shows an alternative "snap-fit ​​cage" locking mechanism, an isometric view of the welded cage elements.

[0080] [Figure 21] FIG. 10 is a side view of another embodiment of a proximal coupler of an outer catheter featuring two locking slots.

[0081] [Figure 22] 22A and 22B depict a monorail microcatheter embodiment of the system, where FIG. 22A is an isometric view of the monorail microcatheter embodiment and FIG. 22B is a side view taken along line AA.

[0082] [Figure 23A] FIG. 1B shows details of an embodiment of the present monorail microcatheter, an isometric view of the proximal portion of the inner catheter connected to the inner catheter hypotube pusher. [Figure 23B] FIG. 1B shows details of an embodiment of the present monorail microcatheter, with a somewhat enlarged detail of the proximal end of the pusher. [Figure 23C] FIG. 10 shows a detail of an embodiment of the present monorail microcatheter, showing a side view of the proximal portion of the inner catheter connected to a hypotube pusher.

[0083] [Figure 24A] FIG. 1 is an isometric view of a coil-reinforced balloon catheter embodiment of the system. [Figure 24B] FIG. 1 is a side view of a coil-reinforced balloon catheter embodiment of the system.

[0084] [Figure 25] FIG. 10 is a perspective view of an embodiment of an outer catheter configured with multiple holes in the outer delivery sheath.

[0085] [Figure 26] FIG. 10 is a perspective view of an embodiment of an outer catheter configured with multiple holes in the outer delivery sheath.

[0086] [Figure 27] FIG. 10 is a schematic diagram of an embodiment of an outer catheter configured with multiple holes in the outer delivery sheath in the proximal section.

[0087] [Figure 28] 1 is a schematic diagram of an embodiment of an outer catheter configured with multiple holes in the outer delivery sheath in the proximal and distal sections.

[0088] [Figure 29A]10A-10C show various examples of hole placement within the sheath, including an embodiment having holes in the distal and proximal sections of the sheath. [Figure 29B] 10A-10C show various examples of hole placement within the sheath, including an embodiment having holes in the distal section as well as the middle and proximal sections of the sheath. [Figure 29C] 10A-10C show various examples of hole placement within the sheath, including an embodiment having holes in the proximal, middle, and distal sections of the sheath.

[0089] [Figure 30] FIG. 1 is a perspective view of one embodiment of an outer catheter configured with multiple holes in the outer delivery sheath.

[0090] [Figure 31A] 10A-10C show various examples of hole sizes in the sheath, including an embodiment in which the holes are of substantially uniform diameter. [Figure 31B] 10A-10C show various examples of hole sizes in the sheath, including an embodiment in which the holes are of variable diameter. [Figure 31C] 10A-10C show yet another embodiment of various examples of hole sizes in the sheath, where the holes are of variable diameter.

[0091] [Figure 32A] 10A-10C show various examples of axial spacing between holes in the sheath, including an embodiment in which the holes are axially spaced at substantially uniform axial spacing on the sheath. [Figure 32B] 10A-10C show various examples of axial spacing between holes in the sheath, and another embodiment in which the holes are axially spaced on the sheath at variable axial spacings. [Figure 32C] 10A-10C show various examples of axial spacing between holes in the sheath, including yet another embodiment in which the holes are axially spaced on the sheath at variable axial spacings.

[0092] [Figure 33A]10A-10C show various examples of radial locations of holes in a sheath, including an embodiment in which the holes are arranged at substantially uniform radial locations on the sheath. [Figure 33B] 10A-10C show another embodiment of various examples of radial locations of holes in a sheath, in which holes are positioned at variable radial locations on the sheath. [Figure 33C] 10A-10C show yet another embodiment of various examples of radial locations of holes in a sheath, where there are holes at multiple radial locations at a single axial location on the sheath.

[0093] [Figure 34A] 10A-10C show various non-circular hole embodiments in the sheath, including an embodiment in which the holes are oval. [Figure 34B] 10A-10C show another embodiment of various non-circular shaped hole embodiments in the sheath, in which the holes are oval. [Figure 34C] 10A-10C show yet another embodiment of various non-circular shaped hole embodiments in the sheath, in which the holes are rectangular. DETAILED DESCRIPTION OF THE INVENTION

[0094] 1-24B illustrate the present intravascular delivery system 10, which includes a guide catheter extension subsystem (also referred to herein as an outer catheter or outer member) and an interventional device delivery subsystem (also referred to herein as an inner catheter or inner member) that cooperate under the control of a surgeon during a cardiac procedure. By way of example only, the interventional device delivery subsystem may be used in one implementation in the delivery of various cardiac interventional devices, but without limiting the scope of the invention to this particular embodiment, the present interventional device delivery subsystem is further described as being adapted for the delivery of a balloon member to perform a pre-dilatation procedure.

[0095] In the exemplary embodiment described herein, the present system 10 may be referred to herein as a guide catheter extension / pre-dilatation system that may be used in a cardiac procedure in conjunction with a guide wire 12 and a guide catheter 14. As shown in FIG. 1 , during the initial stages of a cardiac procedure, a guide wire (GW) 12 is moved into a blood vessel 16 by a surgeon. A guide catheter 14 is advanced along the guide wire 12 through the blood vessel 16 (e.g., the aorta) to a position adjacent an ostium 18 of a coronary artery 20. The guide wire 12 may be used during cardiac surgery to guide the guide catheter 14, after which the present guide catheter extension / pre-dilatation system 10 (inside the guide catheter 14) may be extended within the artery 20 toward a target location 22, as described in more detail in the following paragraphs.

[0096] 2A-2C, the present guide catheter extension / pre-dilatation system 10 includes a balloon catheter subsystem 34 (also referred to herein as an inner catheter, inner member, or pre-dilatation subassembly) and a guide catheter extension subsystem 36 (also referred to herein as an outer catheter). The inner catheter 34 interacts with the outer catheter 36 and can engage or disengage from the outer catheter 36 as required by the cardiac procedure.

[0097] The system 10 includes a proximal section 38, a distal section 40, and an intermediate section 42 extending between and interconnecting the proximal and distal sections 38, 40. A pre-dilatation balloon member 44 is carried on the distal section 40 of the inner catheter 34. The distal section 40 of the inner catheter 34 may also be configured with an elongated tapered microcatheter 46, as described in more detail in the following paragraphs.

[0098] The guide extension / pre-dilatation system 10 is expanded within the lumen (internal channel) 48 of the guide catheter 14, as shown in FIG. 1 . To reliably reach, and possibly pass through, the target location 22, the guide extension / pre-dilatation system 10 is advanced through the guide catheter 14 and beyond the distal end 50 of the guide catheter 14 deep into the coronary artery 20. By extending beyond the distal end 50 of the guide catheter 14, the system 10 provides proper accessibility of the pre-dilatation balloon 44 to the target location 22, and by extending beyond the ostium 18 of the coronary artery 20, it stabilizes the positioning of the guide catheter 14 and allows the system 10 improved accessibility within the coronary artery 20 and to the target site 22.

[0099] As shown in Figures 1, 2A-2B, 3C-3D, 4, 5A-5C, and 6A, the guidewire 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 the proximal end of the GW 12 in the intermediate section 42.

[0100] In operation, the inner catheter 34 and outer catheter 36 are coupled together for advancement (as a single unit) along the guidewire 12 within the guide catheter 14 positioned within the blood vessel 16, extending beyond the distal end 50 of the guide catheter 14 to reach the target lesion site 22. Once the present balloon catheter subsystem (inner member) 34 reaches the lesion site 22 and the balloon member 44 is aligned with the lesion site 22, the intended pre-dilatation procedure may be performed. After pre-dilatation has been performed, the outer catheter (also referred to herein as the outer member) 36 may be advanced across the lesion as a unit with the inner catheter (also referred to herein as the inner member) 34, followed by disengagement of the inner catheter 34 from the outer catheter 36 to withdraw the inner catheter from the outer catheter.

[0101] Alternatively, after the pre-dilation procedure is performed, the inner catheter 34 may be disengaged from the outer catheter 36 as the outer catheter 36 is advanced across the dilated lesion. Additionally, the outer catheter 36 may be left in place near the lesion after the pre-dilation procedure is performed and the inner catheter 34 is removed.

[0102] In either scenario, the outer member (catheter) 36, which remains in proximity to the pre-dilated lesion, may be used to deliver the stent to the lesion site inside the outer member (catheter) 36. Once the stent is placed (deployed) at the lesion site, the outer member 36 is removed from the guide catheter 14.

[0103] As will be presented in a further paragraph, in this system, the inner catheter 34 is prevented from forward displacement inside the outer catheter 36. Only rearward 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 following pre-dilatation of the lesion.

[0104] 2A-2C, the proximal section 38 of the present guide extension / pre-dilatation system 10 is represented by the balloon inflation hub 56 of the inner member 34 (best shown in FIG. 2B) and the proximal end 58 of the outer member 36.

[0105] 2B, 3A-3D, 4, and 5C, inner member (also referred to intermittently herein as the balloon catheter subsystem or pre-dilatation balloon delivery subsystem) 34 is configured with an internal inflation channel 60 extending between inflation hub 56 and pre-dilatation balloon member 44. Internal inflation channel 60 serves as a passageway for inflation air between balloon inflation system 62 (shown schematically in FIG. 2B) and balloon member 44 for controlled inflation / deflation of balloon member 44 as prescribed by the cardiac procedure.

[0106] The internal inflation channel 60 is formed by an inflation lumen hypotube 64 and an inflation lumen distal shaft 66, which overlap and are fluid-tightly interconnected.

[0107] The inflation hub 56, located at the proximal end 68 of the inner member 34, is configured with an internal cone-shaped channel 70 connected by a proximal opening 72 to the balloon inflation system 62 (as shown schematically in FIG. 2B).

[0108] Balloon inflation system 62 may be a manual or automated system. In a preferred automated embodiment, balloon inflation system 62 includes an electronic subsystem, a pneumatic subsystem, and control software with a corresponding user interface. The electronic subsystem provides power to a solenoid pressure valve (fluidically coupled to balloon inflation hub 56) to control the inflation and depressurization of balloon member 44 with a fluid or air flow under the control of the control software.

[0109] 2B, the internal cone-shaped channel 70 of the balloon inflation hub 56 is configured with a distal opening 74 that is coupled to the inflation lumen hypotube 64. The proximal end of the inflation lumen hypotube 64 is coupled to the distal opening 74 of the internal cone-shaped channel 70 of the balloon inflation hub 56 in a fluid-tight manner to support the passage of inflation air between the balloon members 44 in the inflation system 62.

[0110] The inflation lumen hypotube 64 extends the length of the proximal section 38 and part of the mid-section 42 of the system 10, terminating at its distal end 78 in the distal section 40, as shown in FIGS. 2B and 4.

[0111] As shown in Figure 2B, a flexible serrated member 80 is provided at the proximal end 76 of the inflation lumen hypotube 64, which is coupled to the distal end 82 of the balloon inflation hub 56. The serrated flexible member 80 supports the proximal end 76 of the inflation lumen hypotube 64 and provides flexible bending of the structure when manipulated by the surgeon.

[0112] As shown in Figures 2A-2C, 3A-3D, 4, and 5C, the inflation lumen distal shaft 66 extends along the intermediate section 42, between the proximal section 38, and terminates at the distal section 40. Figure 3A details the junction between the inflation lumen hypotube 64 and the inflation lumen distal shaft 66. The inflation lumen hypotube 64 does not extend all the way through the inner member 34, terminating at a distal end 78 (as shown in Figures 2B and 4).

[0113] 3B-3D, the inflation lumen hypotube 64 has a skived distal portion 90 that is coaxially surrounded by the wall of the inflation lumen distal shaft 66, whereby the inflation lumen hypotube 64, together with the inflation lumen distal shaft 66, provides sealed fluid communication between the balloon inflation system 62 and the interior chamber 92 of the balloon member 44, as shown in FIGS. 5A-5C, for controlled inflation / deflation of the balloon member 44 as required by the cardiac procedure.

[0114] 2B and 3C-3D show that the inflation lumen distal shaft 66 is configured with a rapid-exchange (RX) guidewire (GW) port 94 with a GW lumen 96 originating at its proximal end 98. The GW lumen 96 extends between the RX GW ports 94 inside the inflation lumen distal shaft 66 throughout the entire length of the distal section 40 of the inner catheter 34. The GW lumen 96 forms an internal channel with a proximal end 98 corresponding to the RX GW port 94 and a distal end 100 corresponding to the outermost distal end 52 of the distal section 40 of the inner member 34. As shown in FIGS. 6A-6B , in the distal section 40, the GW lumen 96 extends beyond the distal end 102 of the inflation lumen distal shaft 66. The distal end 100 of the GW lumen 96 defines a gradually tapered portion 104, which may be in the form of a delivery microcatheter 46.

[0115] 2A-2B, 5A-5C, 6A-6B, and 24A-24B, the inner catheter (also referred to herein as a balloon catheter subsystem) 34 is configured with a tapered distal portion (also referred to herein intermittently as a tapered distal tip) 162 at the distal section 40. The tapered distal portion 162 is equipped with a pre-dilatation balloon member 44 secured thereon adjacent to the microcatheter 46. The pre-dilatation balloon member 44 is secured to the tapered distal portion (tip) 162 of the inner member to support a pre-dilatation / stenting procedure when needed for cardiac treatment of a patient.

[0116] The balloon member 44 has a proximal portion 112 and a distal portion 114. The balloon member 44 is attached (secured) to the distal section 40 adjacent the delivery microcatheter 46, with the proximal portion 112 coupled to the distal end 102 of the inflation lumen distal shaft 66 and the distal portion 114 of the balloon 44 coupled to the outer surface of the microcatheter 46.

[0117] As shown in Figures 5A to 5C, the pre-expansion balloon 44 has its proximal portion 112 attached to the proximal portion 204 of the distal tip 162 in juxtaposition with and adjacent to the outer tip 164 of the sheath 120, and its distal portion 114 attached to the distal end 166 of the distal portion (tip) 162 of the inner member 34.

[0118] The balloon member 44 may intermittently assume a contracted (folded) configuration and an inflated (expanded) configuration. The contracted (folded) configuration is used during insertion and / or withdrawal of the system from the blood vessel. When in position (target site 22), the balloon is inflated (expanded) to open the blood vessel and compress plaque for a pre-dilatation procedure or stenting procedure (when a stent is delivered to the treatment site on the balloon). When inflated, the balloon 44 assumes the inflated / open configuration shown in FIGS. 2A-2B, 5A, 5C, 6A-6B, and 24A-24B for pre-dilatation of the affected blood vessel. When deflated, the balloon member 44 assumes the contracted configuration shown in FIG. 5B.

[0119] The balloon 44 may have a smooth surface, or a "chocolate" configuration. A "chocolate" balloon catheter is an over-the-wire balloon dilatation catheter with a braided shaft and an atraumatic tapered tip. When inflated, the balloon is constrained by a nitinol structure that creates small "pillows" and grooves in the balloon.

[0120] 2A, 2C, 5A-5C, 7, 8A-8B, 9A, 9C-9D, 10A-10G, 11C, 12B-12C, 13A-13B, 14B, 15A-15D, 16A-16B, 17A-17B, 18A-18B, 19B, 20A-20B, 21, and 24A-24B, outer catheter (also referred to as guide catheter extension subsystem) 36 is formed with a cylindrical outer delivery sheath 120 having an interior channel 122 extending therethrough. A coupler mechanism 130 is formed at and surrounding a proximal end 132 of cylindrical sheath 120.

[0121] At the proximal end 58, the outer catheter 36 includes an outer member pusher (also referred to herein as a pusher / puller) 134, which in one embodiment may be a solid wire, and may have a rounded wire proximal section 136 and a flattened distal portion 138 that may be welded or otherwise fixedly attached to the proximal end 132 of the sheath 130, as shown in Figures 10B-10G, 11A-11C, 12A-12C, 13A-13B, 14A-14B, 15A-15D, 16A-16B, 17A-17B, 18A-18B, 19B, and 22. In another embodiment, the push / pull element 134 may comprise a hypotube.

[0122] Alternatively, the rounded pusher wire can be welded to a flat wire, which is then welded or otherwise fixedly secured to the proximal end 132 of the sheath 120.

[0123] In yet another alternative embodiment of outer member 36, the rounded wire may be welded or otherwise fixedly secured to two flat wires, which are in turn welded or otherwise fixedly secured to proximal end 132 of sheath 120.

[0124] The flat profile of the pusher wire portion is welded to the proximal coupler 130 of the outer sheath 120 so that when the inner member 34 is inserted into the outer member (catheter) 36, the pusher wire does not obstruct rotational or longitudinal movement of the inner catheter 34 inside the proximal coupler 130 and sheath 120 of the outer member 36 as required by the procedure. The proximal push-pull element 134 advances or withdraws the outer tubular sheath 120 and is preferably flexible (not rigid). The pusher / puller 134 may be flexible (not rigid), with flexibility along its longitudinal axis that matches or exceeds that of the tubular outer delivery sheath 120 of the outer catheter 36.

[0125] The outer catheter pusher 134 may be equipped at its proximal end with a proximal handle 140, shown in FIG. 10F, which provides convenience to the surgeon performing the coronary intervention procedure for manipulating the outer member 36 to position the outer delivery sheath 120 together with the balloon delivery subsystem 34 at a desired location relative to the lesion 22 within the affected vessel.

[0126] The proximal (wire or hypotube configuration) push / pull element 134 connected to the outer member tubular structure 120 has a small profile and is flexible (not "rigid") to achieve improved fit within the guide catheter and a lower profile than the rigid "push" elements in conventional guide extension catheters (per Root). This is possible due to the "pushability" of the "whole system" achieved through the locked, integral connection between the outer catheter (with its hypotube push element) and the inner catheter (guide extension tube).

[0127] Additionally, the inner catheter (inner member) 34 may be equipped with an inner member pusher (also referred to herein as a pusher / puller) 142 (shown in FIG. 2A ) that may be attached to the inflation hub 56 to facilitate withdrawal of the inner member 34 from the outer member 36 as required by the coronary intervention procedure, as well as to control the engagement / disengagement therebetween, for various stages of the cardiac procedure. The inner member pusher / puller 142 may be formed with an inner member pusher / puller handle for the convenience of the surgeon performing the procedure.

[0128] The handles of the pushers of the inner and outer members may be configured with a mechanism (as detailed in U.S. Patent Application No. 15 / 899,603, incorporated herein by reference) that allows for additional releasable locking of the inner and outer members relative to one another to enhance the integral cooperation of the inner and outer members in the engaged operating mode.

[0129] The inner member 34 may be in either an over-the-wire or RX configuration. In one of the embodiments detailed herein, the guidewire 12 extends through an RX GW port 94 formed at the proximal end of the tubular inflation lumen distal shaft 66 and into and along the internal channel 146 of the GW lumen 96, as shown in FIGS. 3C-3D and 4. In the distal section 40 of the system 10, the guidewire 12 extends along the delivery tapered microcatheter 46 into the GW lumen (at tapered portion 104) and exits the distal end 100 of the GW lumen 96 at the outermost end 52 of the inner member 34, as shown in FIGS. 2A-2B, 5A-5B, and 6A-6B.

[0130] The outer delivery sheath 120 of the outer member 36 is fabricated using a flexible cylindrical tubular body 150 that extends substantially the length of the mid-section 42 of the system 10. By manipulating the outer member pusher 134, the surgeon actuates the integral advancement of the outer delivery sheath 120 and the inner member 34 along the guide catheter 14. When a pre-dilatation procedure is performed (as will be described in more detail in a further paragraph), the surgeon controls the required linear rearward displacement of the inner member 34 relative to the sheath 120 of the outer member 36 by manipulating the outer member pusher 134 and / or the inner member pusher 142.

[0131] As shown in Figures 8A-8B and 9A-9D, the point of contact between the outer tip 164 of the sheath 120 and the distal tip 162 of the inner member 34 facilitates displacement of the distal tip 162 of the inner member 34 relative to the outer tip 164 of the sheath 120, essentially facilitating displacement of the distal tip 162 relative to the outer tip 164 of the sheath 120 as required by the cardiac procedure.

[0132] The distal end 160, as well as the outer tip 164 of the sheath 120, are formed of a flexible material that allows for simplified retraction of the distal tip 162 of the inner member 34 therethrough. A flat wire helical coil may be used for the distal end 160 and outer tip 164 of the sheath 120.

[0133] At its proximal end 132, the sheath 120 of the outer catheter 36 is configured with an inlet "opening" (or "port") 210 having a circumference that exceeds the circumference of the outer member flexible tubular sheath 120, as shown in FIGS. 10A-10G. The inlet 210 (also referred to herein as the "port") to the interior channel 122 of the sheath 120 may be configured in a variety of variations. For example, as shown in FIG. 10A, the inlet 210 has a funnel shape 211 with an eccentric opening (as shown in FIG. 10A), or is concentrically smooth (as shown in FIGS. 10B-10C), or concentrically sloped (as shown in FIGS. 10D-10E), or alternatively, is contoured with a concentric concave profile (as shown in FIGS. 10F-10G). A pusher 134 is attached to a predetermined point on the funnel-shaped outer catheter proximal inlet 210.

[0134] As shown in FIGS. 2A, 2C, 7, and 8A-8B, the outer delivery sheath 120 of the outer catheter 36 extends between its proximal end 132 at the intermediate section 42 of the system 10 and its distal end 160 at the distal section 40. In the distal section 40 of the guide catheter extension / pre-dilatation system 10, the inner member 34 is configured with a tapered configuration 104 having a distal tapered portion (also referred to herein as a distal tapered tip) 162, which may be formed with a microcatheter 46, as shown in FIGS. 2A-2B, 5A-5B, 6A-6B, 8A, 22A-22B, and 24A-24B. The microcatheter 46 is an elongated, thin member having a length in the centimeter range, e.g., 1-3 cm. The microcatheter 46 has a tapered, conical profile configuration at its distal end 52 with a diameter not exceeding 1 mm. The microcatheter 46 may be integrally formed with the tapered distal tip 162 of the inner member 34 .

[0135] 2A, 5A-5C, 7, and 8A-8B, at its distal end 160, the outer delivery sheath 120 is formed with an outer tip 164 having a tapered conical profile that may be interconnected with a distal tip 162 of the inner member 34. The outer tip 164 of the outer member 36 provides a smooth distal tapered transition between the distal end 160 of the sheath 120 and the distal section 40.

[0136] 2A, 5A-5B, 6A-6B, 8A-8B, 22A-22B, and 24A-24B, the distal tip 162 of the inner catheter 34 is shown as having a tapered configuration that gradually changes from the point of interconnection with the outer tip 164 of the sheath 120 to the distal end 166 of the distal tip 162. The microcatheter 46 extends integrally therewith from the distal end 166 of the distal tapered portion 162 of the inner member 34 (approximately 1-3 cm in length) and terminates at the outermost distal end 52.

[0137] The present guide catheter extension / pre-dilatation system 10 may be configured to provide differential microcatheter flexibility with greater flexibility in the distal portion by either varying the durometer of the plastic (polymer) components from the proximal portion of the outer delivery sheath to its distal portion (i.e., having a higher durometer in the proximal portion relative to the distal portion) and / or by varying the winding frequency (pitch) of the helical coil of wire within the microcatheter 46 from the proximal portion to the distal portion so that the distal portion of the microcatheter 46 is more flexible and trackable than the proximal portion of the microcatheter delivery device, has a substantially lower profile, and is more flexible than the distal portion of the guide catheter extension subsystem (outer delivery sheath).

[0138] The system 10 may also include radiopaque wires to facilitate visualization of the balloon member 44, microcatheter 46, and outer delivery sheath 120 using fluoroscopy. It is envisioned that the distal tip 162 will be provided with radiopaque markers 264, 266 adjacent the proximal and distal portions 112, 114 of the balloon 44 (as shown in FIGS. 5A and 6A-6B). The radiopaque markers 264, 266 allow the surgeon (operator) to visualize the positioning of the balloon member 44 relative to the lesion location 22.

[0139] Additionally, the outermost distal tip 52 of the microcatheter delivery portion 46 and the tip 160 of the sheath 120 may have one or more radiopaque markers 268, 270 (shown in FIGS. 2B and 5A) to allow the surgeon to distinguish the radiopaque markers, which is particularly important when the microcatheter is passed through an occlusive lesion and a balloon member carried adjacent to the microcatheter is held in place.

[0140] 7 , in one embodiment, the outer catheter 36 is configured with a catheter shaft coil reinforcement system 170 disposed on (or embedded in) the inner surface 152 of the sheath 120. Preferably, a lubricious liner 172 is disposed inside the shaft 120. The shaft reinforcement coil 170 may be disposed inside the shaft 120 in contact with the lubricious liner 172, i.e., surrounding the surface of the lubricious liner 172 that covers the inner surface 152 of the shaft 120. A distal soft tip jacket 174 is attached to the distal end of the outer catheter shaft 120 along a longitudinal axis 176 of the outer catheter 36.

[0141] The distal soft tip jacket 174 may be adhered to the shaft 120 at the end 175 (as shown in FIG. 7) or may cover a length of the outer surface 173 of the shaft 120 .

[0142] Distal soft tip jacket 174 extends beyond coil stiffener 170 and lubricious liner 172 at distal end 160 of shaft 120 and terminates in a tapered portion 178 having a distal edge 184 and a proximal edge 182 .

[0143] The lubricious liner 172 may be formed from a PTFE material. The distal soft tip jacket 172 may be formed from a highly flexible, low durometer elastomeric Pebax material that transitions to a higher durometer along the longitudinal axis 176 toward the proximal end 132 of the sheath 120.

[0144] As shown in Figures 7 and 8A-8B, in one preferred embodiment, the inner diameter of the sheath 120 at the inner surface 152 is approximately 0.048 inches, and the outer diameter of the shaft 120 at the outer surface 173 is 0.058 inches. The inner diameter of the tapered section 178 of the outer catheter 36 at its distal edge 184 is approximately 0.045 inches, while the outer diameter of the tapered section 178 at its distal edge 184 is approximately 0.047 inches. The slope between the outer diameter of the sheath 120 (0.058 inches) and the outer diameter of the taper 178 (0.047 inches) defines the taper of the outer surface, while the slope between the inner diameter of the sheath 120 (0.048 inches) at the inner diameter of the taper 178 at its distal edge 184 (0.045 inches) defines the taper of its inner surface. The distal wall 180 of the tapered portion 178 has a thickness decrease from the junction 182 (between the sheath 120 and the tapered portion 178 ) to the outermost edge 184 of the tapered portion 178 of the distal soft tip jacket 174 .

[0145] 7 in conjunction with FIGS. 8A-8B, the outer diameter of the tapered element 104 of the inner catheter has an outer diameter of approximately 0.046 inches, which is approximately 0.001 inch larger than the inner diameter (0.045 inches) of the distal tip of the outer catheter at its outermost distal edge 184. This difference between the outer diameter of the tapered element 104 of the inner catheter 34 and the inner diameter of the distal edge 184 of the outer catheter outer tip 164 causes the distal soft tip jacket 174 to stretch at its tapered portion 178 when it interferes with the tapered element 104 of the inner catheter. Such an arrangement provides a nearly seamless transition between the distal tip of the inner catheter 34 and the distal tip of the outer catheter 36, as well as a compact distal profile due to compression of the distal tip of the inner catheter 34 by the tapered element 178 of the outer catheter 36. Upon removal of the inner catheter 34, the elastomeric distal tip of the distal soft tip jacket 174 of the outer catheter 36 allows the tapered section 178 to return to its original inner diameter (0.045 inches).

[0146] In the disengaged mode of operation, the inner diameter of the wall 180 of the tapered outer tip 164 of the outer member 36 is smaller than the outer diameter of the inner member 34. In the engaged mode of operation, the tapered outer tip 164 of the outer member 36 and the inner member 34 interact such that the dimensional transition between the outer diameter of the tapered outer tip 164 of the sheath lumen 120 and the outer diameter of the distal portion of the inner member 34 forms a substantially flush tangent transition therebetween.

[0147] 9A-9D, the tapered section 178 is contemplated in some embodiments as an expandable tapered design. As shown in FIG. 9A, the resilience of the outer catheter 36 at its distal tapered section 178 is enhanced by an expandable split ring 190 secured to the tapered section 178, thereby allowing the distal outer tip 164 to expand (when contacted by the inner catheter 34). The expandable split ring 190 has slits 192 that allow the ring 190 to expand and contract in response to interference between the inner and outer catheters at their distal ends. This structure provides additional reinforcement to prevent permanent deformation of the tapered section 178 during removal of the inner catheter 34 and delivery of a stent (or balloon).

[0148] 9B, in an alternative embodiment of the outer catheter 36, the tapered section 178 may be configured with an expandable tip scaffold 194 that may be fabricated from NiTi wire and have a distal end 196 and a proximal end 198 that has a diameter larger than that of the distal end 196. Due to its flexibility, the expandable scaffold 194 expands and contracts as needed, providing additional support at the tapered section 178 to resist permanent deformation of the jacket 174 during removal of the inner catheter and delivery of the stent or balloon member.

[0149] Another alternative embodiment of the tapered portion 178 at the distal end of the sheath 120 is shown in Figures 9C-9D, in which the wall 180 of the tapered portion 178 is shaped with slits 200 that extend longitudinally along the length of the tapered portion 178 and flare apart along the periphery. When the tapered portion 178 contacts the distal end of the inner member 34, the slits 200 temporarily expand to encase the distal tip 162 of the inner catheter 34. This design can prevent permanent deformation of the jacket 174 at the tapered portion 178, which may be caused by removal of the inner catheter 34 or during stent / balloon delivery.

[0150] An important "seamless" aspect of the present system is that the transition between the outer diameter of the outer tip 164 of the sheath 120 (at its tapered portion 178) and the outer diameter of the distal tip 162 of the inner member 34 forms a substantially gradual (smooth) transition therebetween.

[0151] As shown in Figures 2C, 10A-10G, 11A-11C, 12A-12C, 13A-13B, 14A-14B, and 15A-15D, the system is constructed in the intermediate section 42 with an interconnection mechanism 220 including a proximal coupler 130 formed at the proximal end 132 of the sheath 120 of the outer member 36 and a cooperating mechanism 222 formed on the outer surface of the inner member 34 (as shown in Figures 17A-17B, 18B, 19A-19B, and 20A-20C).

[0152] The present guide catheter extension / pre-dilating system 10 may operate in an inner / outer catheter engagement mode and an inner / outer catheter disengagement mode, which is achieved by controlling the interconnection mechanism 220. The present interconnection mechanism 220 is configured to engage / disengage the inner and outer catheters 34, 36 (as required by the cardiac procedure) and to prevent undesired forward displacement of the inner member 34 inside the outer delivery sheath 120. The engagement mode of operation allows for improved "whole system" "pushability" (where the outer catheter 36 is connected and locked to the inner catheter 34), even with the connected push / pull element 134 of the outer member 36 configured as a low-profile, flexible element (flexible or more flexible than the outer tubular sheath 120 of the outer catheter 36).

[0153] The interconnection unit 220 operates based on interference between the proximal coupler 130 configured at the proximal end 132 of the sheath 120 and the cooperating mechanism 222 configured on the outer surface 224 of the inner member 34 when the inner surface 152 of the tubular body 150 of the sheath 120 (at the proximal end 132) engages with the outer surface 224 of the cooperating mechanism 222 (on the inner member 34).

[0154] By way of example, several interconnection mechanisms are envisioned as being applicable to the present guide catheter extension / pre-dilatation system 10. The engagement mechanism of the present invention is configured for controllable engagement / disengagement between the inner member 34 and the outer member 36, as well as to prevent forward movement of the inner member 34 relative to the outer delivery sheath 120 beyond a predetermined position.

[0155] 11A-11C, the laser-cut coupler 130 may be configured with a proximal open (split) ring 240 and a pair of distal rings including a solid distal ring 242 and an open (split) distal ring 244. The proximal open ring 240 and the distal rings 242 and 244 are integrally formed with a coupler base 246. The coupler 130 may be formed from stainless steel or heat-set NiTi. The pusher / puller element 134 of the outer catheter 36 and the mid-shift coupler (also referred to herein as the proximal coupler) 130 may be made from a memory metal (e.g., Nitinol, etc.) to prevent deformation during antegrade or retrograde movement of the outer member and to prevent any deformation of the mid-shaft coupler 130 while a stent (or other device) is passing through the mid-shaft portion of the outer catheter 36.

[0156] The release ring 240 correlates with the proximal inlet opening (e.g., funnel-shaped) 211 of the outer catheter 36 (shown in FIGS. 10A, 10D-10E, and 11C). The proximal release ring 240 allows for the enlargement of the inlet 211 into the funnel 210 as needed for entry / removal of the inner catheter 34 when required by the surgical procedure. As shown in FIGS. 10A, 10D-10E, and 11A-11C, the proximal release ring 240 provides support for the proximal opening 210 at the proximal end of the funnel shape of the sheet 120. The proximal ring 240 reinforces the inlet opening ("mouth") 211, preventing damage or permanent deformation of the inlet opening, and 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 that is separate from the proximal release ring 240 of the funnel. The distal ring 242 is not expanded (is of a closed circular contour), but the openings of the split rings 244 expand during displacement of the inner catheter 34 relative to the proximal coupler 130 of the outer catheter 36 .

[0157] The base 246 of the coupler 130 may be flat, as shown in Figures 11B-11C, or preferably is slightly arcuate (in cross section) to match the cooperating distal end 250 of the pusher 134, which has a flat or crescent-shaped (cross-sectional) profile. The pusher 134 may be fabricated from stainless steel or NiTi. The distal end 250 of the pusher 134 is welded (glued, adhesively bonded, or otherwise attached) to the base member 246 of the coupler 130. A PTFE liner 172 (also shown in Figure 7) may encapsulate the coupler 130, as shown in Figure 11C.

[0158] The sheath 120 is disposed in surrounding relationship with the coupler and a PTFE liner 172. A Pebax encapsulation similar to the distal soft tip jacket 174 at the distal end 160 of the sheath 120 (shown in FIG. 7) may be used at the proximal end 132 of the sheath 120. A catheter shaft coil reinforcement 170 (also shown in FIG. 7) at the distal end of the outer catheter 36 may extend its length to the proximal end of the outer catheter 36.

[0159] As shown in Figures 11A-11C, 17A-17C, and 18A-18B, the cooperating mechanism 222 for the particular embodiment shown in Figures 11A-11C further includes a mid-shaft locking ring 252 (shown in Figures 17B-17C and 18B) for a snap-fit ​​lock.

[0160] Another embodiment of the outer catheter proximal inlet configuration shown in FIGS. 12A-12C is similar to that shown in FIGS. 11A-11C, with certain modifications including the following.

[0161] (a) additional thickness and additional material around the base 246 of the coupler 130;

[0162] (b) modified surface treatments (e.g., bead blasting) to improve polymer encapsulation adhesion, and

[0163] (c) The use of a hard polymer (e.g., nylon) encapsulation to provide additional support to the funnel and prevent damage that may prevent stent passage.

[0164] An additional embodiment of coupler 130 at the proximal inlet 210 (shown in FIGS. 13A-13B) features open rings (ribs) 256 that reinforce the inlet port 210. A snap-fit ​​lock 260 is represented by at least two open rings 262 at the distal end of coupler 130. Coupler 130, as shown in the modified form presented in FIGS. 13A-13B, is preferably a laser-cut coupler formed from either stainless steel or heat-set NiTi.

[0165] The hypotube pusher / puller 134 may be flattened at its distal end 250 and welded to the base 246 of the coupler 130. A PTFE liner 172 extends beneath the coupler 130, and a Pebax enclosure 174 surrounds the coupler 130 with the pusher 134 attached. A catheter shaft coil reinforcement structure 170 extends along the shaft 120 of the outer catheter 36 from its distal end to its proximal end. A snap-fit ​​lock 260 cooperates with the rounded ring embodiment of the cooperating feature 222 shown in FIGS. 17A-17C and 18B. In some embodiments, the enclosure 174 and / or the pusher / puller 134 may be color-coated with different colors, as shown in FIG. 11A, to distinguish the outer member pusher / puller 134 from other elements of the arrangement for the surgeon's convenience and procedural safety.

[0166] A further modification of coupler 130 is shown in Figures 14A-14B, where coupler 130 has individual rings 266, 268 welded to the distal end 250 of pusher 134. As shown, locking mechanism 260 is formed by a solid distal ring 266 and an intermediate split ring 268, with each ring 266, 268 welded to pusher 134. A proximal angled split ring 270 is also welded to pusher 134. This design allows for greater flexibility in the size and configuration of each ring 266, 268, and 270, and supports the formation of different funnel shapes / dimensions, as opposed to laser-cut couplers, which are limited to a single diameter.

[0167] 15A-15B show another variation of the proximal coupler 130 featuring funnel fenestrations that improve contrast injection flow rates by providing additional open cross-sectional paths for fluid flow. As shown in FIGS. 15A-15B, circular openings 272 are formed in the sheath 120. The openings 272 are non-occlusively arranged in a predetermined pattern with the proximal split ring 274 and distal rings 276, 278 of the snap-fit ​​locking structure 280. As shown in FIGS. 15C-15D, the coupler 130 is formed with a triangular opening 282 formed in the sheath 120 in a non-occlusive manner by the proximal split ring 274 and distal rings 278, 276 of the snap-fit ​​locking structure 280.

[0168] Although only circular and triangular openings 272, 282 are shown in Figures 15A-15D, respectively, other configurations of the cutouts within the plastic enclosure are also contemplated in this structure to allow injected contrast fluid to pass through the cutouts.

[0169] 16A, 16B, and 16C, another embodiment of the proximal end of the outer catheter 36 is shown, specifically designed as a potential solution to prevent undesirable embolization situations when air inadvertently enters between the inner and outer catheters 34, 36 along with the injected fluid. To prevent this, a flush lumen 290 is incorporated into the pusher 134 via a flat hypotube. A luer hub is coupled to the proximal end of the hypotube (pusher 134), as shown in FIG. 16C, allowing the surgeon to inject fluid between the inner and outer catheters via the hypotube 134. Once fluid enters the outer catheter lumen 292 via the channel 290 in the hypotube 134, the ingress of air bubbles between the inner and outer catheters is prevented.

[0170] 17A-17C, the interconnection unit 220 between the proximal couplers 130 presented in FIGS. 11A-11E, 12A-12C, 13A-13B, 14A-14B, and 15A-15D includes a cooperating member 222 in the form of an annular, rounded ring 252 (also referred to herein as a central locking ring) formed on the outer surface 224 of the inner catheter 34. The stainless steel annular ring 252 is contoured with a fully rounded surface that allows for minimal reversible engagement / disengagement from the required split ring mechanism of the outer catheter coupler 130. The ring 252 shown in FIG. 17C has a rounded contour on its outer surface 302 for a 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.

[0171] Figure 17A shows the disengaged configuration of the inner catheter 34 relative to the outer catheter 36. Figure 17B depicts the locked and engaged configuration when the inner catheter 34 is received and locked inside the opening 210 at the proximal end of the sheath 120 such that the ring 252 engages the snap-fit ​​lock 306 formed by the distal solid ring 308 and the middle split ring 310. While in place, the proximal angled split ring 312 surrounds the inner catheter 34 and the ring 252 is locked into the snap-fit ​​lock 306, thus engaging the inner and outer catheters for surgical manipulation as required by the surgical procedure.

[0172] During longitudinal movement of the inner catheter 34 within the outer catheter 36, as the ring 252 passes through the proximal angled split ring 312 and the middle split ring 310, the arms of these rings expand from their original positions to create enough 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 arms of the angled split ring 312 and the split ring 310 return to their original closed positions. The ring 252 is captured between the rings 308 and 310 and is snap-fit ​​locked therebetween, thus preventing relative displacement of the inner and outer catheters.

[0173] 18A-18B, which detail the structure shown in Figures 17A-17C, show that a section (pocket) 316 of the sheath 120 of the outer catheter 36 is not reinforced by the coil 170 and will deflect when the mid-shaft locking ring 252 is inserted between the solid distal ring 308 and the mid-split ring 310 of the snap-fit ​​lock 306. The deflecting portion 316 of the sheath 120 between the rings 308 and 310 provides additional retention force to maintain the inner and outer catheters 34, 36 in locked engagement.

[0174] The stainless steel annular ring 252 may be attached to the outer surface 224 of the inner catheter shaft 34 via adhesive. The locking ring's shape (fully rounded surface) allows for smooth, reversible engagement / disengagement from the laser-cut features of the outer catheter coupler 130. The distal ring 308 of the snap-fit ​​lock 306 prevents further distal movement of the inner catheter 34, while the middle split ring 310 opens upon contact with the mid-shaft locking ring 252, providing a tactile snap. The proximal angled split ring 312 allows the funnel 211 to open to a larger inner diameter than the rest of the shaft 120. It also allows for smooth passage of the mid-shaft locking ring 252.

[0175] The interference between the unreinforced shaft pocket 316 and the mid-shaft locking ring 252 provides retention of the inner catheter 34 relative to the outer catheter 36 until the user is ready to remove the inner catheter 34 from the outer catheter 36, thus releasing the snap-fit ​​lock therebetween. The force required to disengage the locking mechanism can be adjusted from 0.1 to 2.0 pounds.

[0176] 19A-19C, another alternative embodiment of a midshaft lock is shown, including a square annular ring 320 (formed of a metal or polymeric material). Unlike ring 252 shown in FIGS. 17A-17C and 18B, ring 320 has a square cross section 321, as shown in FIG. 19C. Square annular ring 320 is secured to the outer surface 224 of inner catheter 34 using a heat-sealed Pebax encapsulation 322. Alternatively, it may be glued to the inner catheter outer surface 224. As shown in FIG. 19B, when the inner catheter is in the locked position, square annular ring 320 snaps into snap-fit ​​lock 324 formed by solid ring 326 and split ring 328, with encapsulation 322 contacting the inner surface 152 of sheath 120 and ring 320 positioned between rings 326 and 328.

[0177] In a further alternative embodiment shown in Figures 20A-20C, the midshaft locking mechanism 220 is formed with a cooperating member 222 in the form of a cage-shaped structure 330 having two NiTi rings 332, 334 connected to one another via several (e.g., four) NiTi shape-setting wires 336. As shown in Figure 20A, the cage 330 is secured to the outer surface 224 of the inner catheter 34 by either adhesive or heat-sealed Pebax encapsulations 338. Each of the wires 336 has an arcuate extension 340 that is left free of the encapsulation 338, as shown in Figures 20A and 20B.

[0178] 20B, in the locked configuration, the cage structure 330 snaps onto the coupler 130 of the outer catheter. An unenclosed arcuate portion 340 of each wire 336 extends away from the wire 336 of the cage 330 outside of the enclosed portion 338. When the cage 330 is received between the ring 342 and split ring 344 of the snap-fit ​​mechanism 346, the locking mechanism 346 is actuated, and the inner and outer catheters 34, 36 are engaged.

[0179] Still referring to FIG. 21, the proximal coupler 130 of the outer catheter 36 may include two locking slots 350 , 352 formed by rings 354 and 356 connected with a connecting element 358 .

[0180] 17A-17C, 18A-18B, 19A-19B, 20A-20C, as well as 10A-10G, 11A-11C, 12A-12B, 13A-13B, 14A-14B, 15A-15D, and 21, when the surgeon linearly displaces the inner member 34 within the internal channel 122 of the proximal coupler 130, the snap-fit ​​annular ring 252, 320 or cage 330 enters the channel 122 between the arms of the proximal rings 240, 312, and the arms are flexibly bent outward to allow forward movement (towards the distal tip 162) of the inner catheter 34. When the snap-fit ​​annular ring 252, 320 or cage 330 passes further through the intermediate split ring 244, 262, 268, 310, 328 of the snap-fit ​​lock, the arms of the angled proximal ring return to their original position, while the arms of the intermediate split ring flex outward, allowing the ring 252, 320 of the cage 330 to assume a position between the distal solid ring and the intermediate split ring. The arms of the intermediate split ring return to their original position once the ring / cage 252, 320, 330 is snapped between the rings of the snap-fit ​​locking mechanism.

[0181] To disengage the inner member 34 from the outer member 36, the surgeon pulls the inner member 34 from the interior channel of the proximal coupler 130. During removal of the snap-fit ​​annular rings / cages 252, 320, 330 from the channel, the pulling action bends the arms of the middle split ring outward to allow passage of the snap-fit ​​annular rings / cages 252, 320, 330 therebetween, thus releasing the inner catheter 34 from the proximal coupler 130 of the outer catheter 36.

[0182] 3D, the inflation lumen distal shaft 66 of the intermediate section 42 of the present guide catheter / pre-dilatation extension system 10 may be manufactured with a braided reinforcement structure 260. The braided reinforcement member 260 creates a somewhat flexible tubing that is connected to a cooperating feature 222 of the interconnect unit 220 of the inner member 34. An RX (rapid exchange) port 94 for passage of a guidewire 12 may be formed through the wall of the braided reinforced inflation lumen distal shaft 66.

[0183] The braided reinforcement structure 260 may be configured with a metal pattern or wire within the braided reinforced inflation lumen distal shaft 66 to prevent kinking, thereby providing longitudinal stiffness to the shaft 66. The metal braid 260 may be embedded within the braided reinforced shaft 66 to add the increased flexibility necessary to retract the inner member 34 relative to the outer delivery sheath 120 during the procedure.

[0184] A flat wire helical coil (e.g., made from a shape memory alloy such as Nitinol) having a wire thickness of about 1 mil to 3 mils may be embedded in the braid 260. This coil may be formed with a very thin coating of plastic disposed on its inner and outer surfaces, which facilitates reducing the wall thickness of the inflation lumen distal shaft 66 to less than 7 mils, preferably about 5 mils.

[0185] The principle of reinforcing a tubular member with or forming a tubular member from a catheter shaft coil reinforcement 170 in the form of a flat wire helical coil 262 is shown in the present guide catheter extension / pre-dilatation system 10 (FIGS. 7, 8B, 9A-9D, 10A, 11C, 12B-12C, 13A-13B, 14B, 15A-15C, 16A-16B, 17A-17B, 18A-18C, 19A-19D, 20A-20C, 21A-21B, 22A-22C, 23A-23B, 24B, 25A-25C, 26A-26B, 27A-27B, 28A-28C, 29A-29D, 30A-30C, 31A-31B, 32A-32C, 33A-33B, 34A-34C, 35A-35C, 36A-36B, 37A-37B, 38A-38C, 39A-40C, 41A-41B, 42A-42B, 43A-43B, 44A-44B, 45A-45C, 46A-46B, 47A-47B, 48A-48C, 49A-49B, 50A-50B, 51A-51C, 52A-52B, 53A-53B, 54A-54C, 55A-55C, 56A-56B, 57A-57B, 58A-58C, 59A-59B, 60A 8B, 19B, 20B, and 21, and to the microcatheter 46 (as shown in FIGS. 2A-2B, 5A, 22, and 24A-24B). In the outer delivery sheath 120 and / or microcatheter 46, such flat wire helical coils may be embedded at predetermined locations along the length of their walls, for example, at the proximal and / or distal ends.

[0186] Alternatively, the entire length of the outer delivery sheath 120 and / or microcatheter 46 may be formed with flat wire helical coils. The pitch between the coils may be adjusted to provide an increasing flexibility gradient along the length of the tubular member (sheath 120 and / or microcatheter 46) toward the distal end to facilitate atraumatic manipulation.

[0187] 22A-22B and 23A-23C, rather than utilizing a standard over-the-wire (OTW) guidewire lumen, a monorail rapid exchange (RX) design of the inner catheter 34' may be implemented to allow for the use of a short guidewire. In the embodiment shown in FIGS. 22A and 22B, which depict an isometric view of a coil-reinforced inner member shaft 400 of the present invention and a side view thereof along line AA, the distal section 40' of the inner member 34' includes a tapered element 402 attached to the outer surface 224 of the inner member 34. The outer shaft 400 of the inner member 34' is a coil reinforced with a coil reinforcement structure 404 that extends from a distal tip 406 to the RX inlet port 94 shown in FIGS. 2A-2C and 3C-3D. The distal tip 406 is a tapered soft tip that, together with the tapered element 402, abuts the inner surface of the outer catheter 36 when the inner catheter 34' is loaded into the outer catheter 36 as required by the surgical procedure.

[0188] The distal section 40' includes a concentric guidewire lumen 408, which communicates with the RX inlet port at the proximal end of the inner catheter 34 (shown in Figures 2A-2C and 3C-3D).

[0189] As shown in Figures 23A-23C, the proximal end 412 of the monorail microcatheter embodiment shown in Figures 22A-22B utilizes a skived hypotube pusher 414. The proximal end 412 of the coil-reinforced inner member shaft 416 and the hypotube pusher 414 are enclosed within a proximal outer jacket 418, which extends as a tube from (and including) the coil-reinforced inner member shaft 416 and hypotube pusher 414 (which functions as a guidewire lumen) 408 shown in Figures 22A-22B along the proximal end 412 of the monorail microcatheter embodiment of the inner member 34'.

[0190] 23A-23B features an RX guidewire "notch" termination / entrance 420 fabricated by puncturing the proximal outer jacket 418. The coil-reinforced inner member shaft 416 is then inserted into the proximal outer jacket tubing 418 through the RX entry "notch" 420. The skived hypotube 415 is further inserted into the proximal outer jacket tubing 418 via its lumen 422, and the polymers of the coil-reinforced inner member shaft 416 and the proximal outer jacket tubing 418 are fused together to connect the inner member shaft 416 and the pusher 414, and thus form the proximal end 412 of the monorail microcatheter inner member 34'.

[0191] For the convenience of the surgeon, the push / pull element 134 of the outer catheter 36 may be color coated, as shown in Figure 11A, to have a distinctive color to distinguish it from other elements of the system, such as the push / pull element of the inner catheter 34, as well as the usual gray or silver color of the coronary guidewire used to deliver the device or stent delivery system. Alternatively, the proximal outer jacket 418 of the push / pull element 414 may be color coated to distinguish its color from the colors of other elements in the system.

[0192]

[00111] With further reference to Figures 24A-24B, which depicts an additional coil-reinforced balloon catheter embodiment 500 of the inner catheter, this structure combines the reinforced shaft characteristics of the microcatheter 46 with the reinforced shaft characteristics of the dilatation balloon 44, which has the following properties:

[0193] a. The coil reinforced shaft 502 provides additional kink resistance and pushability while still maintaining flexibility for navigating tortuous vasculature.

[0194] b. The longer distal tip 504 of the structure includes a low profile tapered soft tip to facilitate crossing strictures and narrow lesions.

[0195] 24A-24B, the distal section 504 of the structure 500 includes an inner member shaft 500 reinforced with a coil reinforcement structure 506 that extends the length of the inner member shaft 500. A distal tapered element 508 is disposed on the inner member shaft 500 and extends between ends 510 and 512 in surrounding relationship therewith. A distal tapered soft tip 514 may be in the form of a microcatheter 46 disposed at the end of the coil reinforced shaft 500.

[0196] 22A-22B, balloon member 44 is disposed over inner member shaft 500 with radiopaque markers 264 and 266 disposed on inner member shaft 500 within balloon member 44. At its proximal end 516, balloon member 44 interferes with outer tip 164 of proximal tapered element 178 of outer member sheath 120. At its distal end 518, balloon member 44 snugly encases shaft 500.

[0197] 1-24B , in operation, to perform a cardiac procedure, specifically a pre-dilatation routine, the proximal end of the coronary guidewire 12 enters the RX port 94 formed in the inflation lumen distal shaft 66 and extends through the inner channel (GW lumen 96) of the inner member 34 toward and beyond the outermost distal end 52 of the microcatheter 46. The guide catheter 14 is then advanced into the blood vessel 16 of the target.

[0198] Subsequently, the outer delivery sheath 120 of the inner member 34 and locked outer member 36 is first positioned within the inner channel 48 of the guide catheter 14 along with the microcatheter 46, and both the inner member 34 and outer member 36 are advanced together as a single unit within the guide catheter 14 toward the treatment site 22. The outer member sheath 120 and inner member 34 may be displaced together by pushing the outer member pusher 134. This action causes the microcatheter 46 of the inner member 34, along with the outer member 36, to extend beyond the distal end 50 of the guide catheter 14 and slide along the GW 12 until they reach the lesion site 92. At this step of the procedure, the balloon member 44 is in its deflated configuration.

[0199] The guidewire 12 extending beyond the distal end 50 of the guide catheter 14 acts as a guide along which the microcatheter 46 (with the deflated balloon 44 attached to its distal tip 162) slides toward the treatment site 26.

[0200] The balloon member 44 (positioned at the treatment site 22) is then inflated by a balloon inflation system 62 connected to the inflation hub 56 through an inflation lumen formed by the inflation lumen distal shaft 66 and the inflation lumen hypotube 64 to compress the plaque and widen the blood passageway within the blood vessel 16.

[0201] Subsequently, once the lesion has been dilated, the balloon 44 may be deflated and the outer delivery sheath 120 may be advanced across the lesion 22 as a unit with the inner member 34 (in the engaged actuation mode), and the inner member may then be disengaged (unlocked) from the outer delivery sheath 120 and removed from the sheath 120.

[0202] Alternatively, inner member 34 may be disengaged and withdrawn from sheath 120 immediately after lesion dilation while outer member 36 is advanced across lesion 22 .

[0203] The sheath 120 may be left in place (immediately after dilation of the lesion) proximal to the treatment site.

[0204] After retracting inner member 34, the stent can be delivered to site 22. The stent may be introduced into vessel 16 inside sheath 120 in its closed configuration. Once in place, a stent support balloon (not shown) may be expanded, thus opening the stent. Outer delivery sheath 120 is then removed, leaving the open stent in vessel 16.

[0205] 25-35C, the outer catheter (also referred to herein as a guide catheter extension subsystem) 36 may be configured with one or more holes 600. The outer catheter 36 may be formed with a cylindrical outer delivery sheath 120 having an internal channel 122 extending along its interior. The outer delivery sheath 120 of the outer member 36 may be manufactured with a flexible, cylindrical tubular body. The outer delivery sheath 120 may include a proximal end 132 and a distal end 160, as shown in FIG. 29A. The outer catheter 36 may have any of the features of the outer catheter 36 described herein.

[0206] The one or more holes 600 can facilitate the passage of fluid through the circulatory or lymphatic system. The one or more holes 600 can aid in distal perfusion. The one or more holes 600 can aid in continuity of flow rate during a procedure. The one or more holes 600 can aid in consistency of blood flow rate during a procedure. Perfusion must be maintained during a surgical procedure. Hemodynamic management can be important to the success of the procedure.

[0207] The one or more holes 600 can have several advantages. The one or more holes 600 can reduce or eliminate the risk of myocardial ischemia in interventions within distal arteries. Myocardial ischemia can occur when blood flow to a patient's heart is reduced. Because an artery in the heart is partially blocked, the heart muscle does not receive enough oxygen. The one or more holes 600 can increase blood perfusion, allowing oxygenated blood to reach the heart muscle while the outer catheter is deployed within the affected coronary artery.

[0208] In some embodiments, the outer delivery sheath 120 of the outer member 36 can be modified to include one or more holes 600. The one or more holes 600 can function as perfusion holes. In some embodiments, the one or more holes 600 can be located at or near the proximal end of the outer member 36. In some embodiments, the one or more holes 600 can be located at or near the midsection of the outer member 36. In some embodiments, the one or more holes 600 can be located at or near the distal end of the outer member 36. In some embodiments, there can be segments without perfusion holes, such as segments between the proximal and distal ends. The proximal segment of the outer member 36, including the proximal side holes 600, can seat in a coronary artery or possibly other artery. The proximal segment of the outer member 36 can be subjected to arterial pressure. This blood pressure can allow blood to enter the one or more proximal holes 600 and exit the one or more distal holes 600. If no distal holes are provided, blood pressure can allow blood to enter one or more proximal holes 600 and exit the distal end 160 of the outer catheter 36 .

[0209] 25 is a perspective view of an embodiment of an outer catheter 36 configured with multiple holes 600 in the outer delivery sheath 120. The one or more holes 600 can be laser cut. The one or more holes 600 can be machined or drilled. The one or more holes 600 can be formed in the sheath 120 during manufacturing of the sheath 120. The one or more holes 600 can be formed in the sheath 120 after manufacturing of the sheath 120.

[0210] The one or more holes 600 can be formed in the coiled or braided catheter structure of the sheath 120. The sheath 120 can be reinforced with a braid. The sheath 120 can be reinforced with a braid with a coil. The sheath 120 can be reinforced with a structure embedded in a polymer matrix. The one or more holes 600 can extend completely through the coiled or braided catheter structure of the sheath 120. The one or more holes 600 can extend completely through the sheath 120 into the inner channel 122.

[0211] Two or more holes 600 can have the same diameter or cross-sectional dimension. Two or more holes 600 can have different diameters or cross-sectional dimensions. Figure 25 shows three holes 600 with different diameters. In some embodiments, the diameter of the holes 600 can be 25 micrometers, 50 micrometers, 75 micrometers, 100 micrometers, 125 micrometers, 150 micrometers, 175 micrometers, 200 micrometers, 225 micrometers, 250 micrometers, 275 micrometers, 300 micrometers, 325 micrometers, 350 micrometers, 375 micrometers, 400 micrometers, 425 micrometers, 450 micrometers, 475 micrometers, 500 micrometers, 600 micrometers, 700 micrometers, 800 micrometers, 900 micrometers, 1000 micrometers, 1100 micrometers, 1200 micrometers, a value between two of the foregoing values, or any range.

[0212] FIG. 26 is a perspective view of an embodiment of an outer catheter 36 configured with multiple holes 600 in the outer delivery sheath 120. In some embodiments, one or more holes 600 are aligned. In FIG. 26, the multiple holes 600 are aligned. The multiple holes 600 can include a first set of holes having a first, larger diameter. The multiple holes 600 can include a second set of holes having a second, smaller diameter. The number of holes 600 in the first set and the second set can be the same. The number of holes 600 in the first set and the second set can be different. The size of the holes 600 in the first set and the second set can be the same. The size of the holes 600 in the first set and the second set can be different.

[0213] FIG. 27 is a schematic diagram of an embodiment of an outer catheter 36 configured with multiple holes 600 in the outer delivery sheath 120 in the proximal section. The outer catheter 36 can be positioned within a blood vessel. The proximal section of the outer catheter 36 can be within the proximal blood vessel. The multiple holes 600 can be considered proximal perfusion holes. The multiple holes 600 can receive blood flow from a blood vessel, such as an artery. The blood vessel can be reduced along the length of the outer catheter 36. There can be a reduction in blood vessel size. The blood vessel can branch. The blood vessel can be tortuous. The blood vessel can be reduced in size due to disease. The distal blood vessel can have a smaller cross-section than the proximal blood vessel. Blood can flow from the distal end 160 of the sheath 120. The direction of blood flow is indicated by the arrows. The multiple holes 600 can function as perfusion holes. The multiple 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 proximal to distal vessels. The plurality of holes 600 can reduce or eliminate the risk of myocardial ischemia by promoting blood flow.

[0214] FIG. 28 is a schematic diagram of an embodiment of an outer catheter 36 configured with multiple holes 600 in the outer delivery sheath 120 in the proximal and distal sections. The proximal section of the outer catheter 36 can be in a proximal blood vessel. The multiple holes 600 can be considered proximal perfusion holes. The distal section of the outer catheter 36 can be in a distal blood vessel. The multiple holes 600 can be considered distal perfusion holes. The multiple proximal holes 600 can receive blood flow from a blood vessel, such as an artery. Blood can flow from the multiple distal holes 600 and the distal end 160 of the sheath 120. The direction of blood flow is indicated by arrows. The multiple proximal holes 600 can be arranged circumferentially. The multiple proximal holes 600 can form one or more circumferential rings. The multiple proximal holes 600 can be equally spaced around the sheath 120. The multiple proximal holes 600 can be arranged longitudinally. The plurality of proximal holes 600 can form one or more longitudinal lines. The plurality of proximal holes 600 can be arranged axially. Each of the plurality of proximal holes 600 can have the same size. Each of the plurality of proximal holes 600 can have different sizes.

[0215] The multiple distal holes 600 can be arranged circumferentially. The multiple distal holes 600 can form one or more circumferential rings. The multiple distal holes 600 can be equally spaced around the sheath 120. The multiple distal holes 600 can be arranged longitudinally. The multiple distal holes 600 can form one or more longitudinal lines. The multiple distal holes 600 can be arranged axially. Each of the multiple distal holes 600 can have the same size. The multiple distal holes 600 can have different sizes.

[0216] The plurality of proximal holes 600 and the plurality of distal holes 600 can have the same pattern or arrangement. The plurality of proximal holes 600 and the plurality of distal holes 600 can have different patterns or arrangements. Each of the plurality of proximal holes 600 and the plurality of distal holes 600 can have the same size or shape. The plurality of proximal holes 600 and the plurality of distal holes 600 can have different sizes or shapes. The plurality of proximal holes 600 and the plurality of distal holes 600 can have the same number of holes. The plurality of proximal holes 600 and the plurality of distal holes 600 can have different numbers of holes.

[0217] 29A-29D show various example arrangements of holes 600 within the sheath 120 of the outer catheter 36. As shown in FIGS. 29A-29C, the sheath 120 may include a proximal section 610, a distal section 620, and a middle section 630. The middle section 630 may extend between and interconnect the proximal section 610 and the distal section 620. The proximal section 610 is near the proximal end 132. The distal section 620 is near the distal end 160.

[0218] 29A shows an embodiment of an outer catheter 36 having holes 600 in the sheath 120. The distal section 620 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range between two of the aforementioned values. The proximal section 610 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range between two of the aforementioned values. The distal section 620 can include a hole in combination with the proximal section 610 that includes a hole. The distal section 620 can include two or more holes in combination with the proximal section 610 that includes a hole. The distal section 620 can include a hole in combination with the proximal section 610 that includes two or more holes. The distal section 620 can include two or more holes in combination with the proximal section 610 that includes two or more holes. The distal section 620 can include two or more holes in combination with the proximal section 610 that includes two or more holes. The ratio of holes in the distal section 620 to holes in the proximal section 610 can 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 can include one or more holes 600 over 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 or more of the aforementioned values. The proximal section 610 can include one or more holes 600 over 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 or more of the aforementioned values. The middle section 630 may include an area without holes 600 .

[0219] 29B shows another embodiment of an outer catheter 36 having holes 600 in the sheath 120. The distal section 620 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The distal end of the mid-section 630 can include a region without holes. The mid-section 630 and the proximal section 610 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The proximal end of the proximal section 610 can include a region without holes. The proximal section 610 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The mid-section 630 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The proximal section 610 can include a hole in combination with the mid section 630 that includes a hole. The proximal section 610 can include two or more holes in combination with the mid section 630 that includes a hole. The proximal section 610 can include a hole in combination with the mid section 630 that includes two or more holes. The proximal section 610 can include two or more holes in combination with the mid section 630 that includes two or more holes. The ratio of holes in the proximal section 610 to holes in the mid section 630 can 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.

[0220] The mid-section 630 can include a hole in combination with the distal section 620 including a hole. The mid-section 630 can include two or more holes in combination with the distal section 620 including a hole. The mid-section 630 can include a hole in combination with the distal section 620 including two or more holes. The mid-section 630 can include two or more holes in combination with the distal section 620 including two or more holes. The ratio of holes in the mid-section 630 to holes in the distal section 620 can 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] 29C illustrates yet another embodiment of an outer catheter 36 having holes 600 in the sheath 120. The proximal section 610 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The middle section 630 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The distal section 620 can include one or more holes, such as one hole, two holes, three holes, four holes, five holes, or any range of two of the aforementioned values. The proximal section 610 can include one or more holes, in combination with the middle section 630 including one or more holes and the distal section 620 including one or more holes. The ratio of holes in the proximal section 610 to holes in the middle section 630 and the distal section 620 can be any suitable ratio. The holes 600 may be continuous along the length of the sheath 120 or a portion thereof.

[0222] The holes 600 in the sheath 120 may allow fluid flow. For example, the holes 600 in the sheath 120 may allow blood to flow substantially from the proximal section 610 of the sheath 120 in a direction substantially toward the distal section 620 of the sheath 120.

[0223] In one embodiment, the operative outer catheter 36 may be positioned within a patient such that the patient's arterial pressure causes blood to flow into the holes 600 in the proximal section 610 and out the holes 600 in the distal section 620. In another embodiment, the operative outer catheter 36 may be positioned within a patient such that the patient's arterial pressure causes blood to flow into the holes 600 in the proximal section 610 and out the holes 600 in the mid-section 630. In yet another embodiment, the operative outer catheter 36 may be positioned within a patient such that the patient's arterial pressure causes blood to flow into the holes 600 in the mid-section 630 and out the holes 600 in the distal section 620. The outer catheter 36 may be configured in any other configuration to allow blood to flow substantially from the proximal section 610 of the sheath 120 to substantially toward the distal section 620 of the sheath 120.

[0224] 30 is a perspective view of one embodiment of the outer catheter 36 configured with multiple holes 600 in the outer delivery sheath 120. The holes 600 can be of the same diameter or cross-sectional size. The holes 600 can be arranged along a line. The holes 600 can be in any portion of the sheath 120 described herein.

[0225] 31A-31C show various example sizes of the holes 600. FIG. 31A shows an embodiment in which the holes 600 are substantially uniform in diameter. FIG. 31B shows an embodiment in which the holes 600 are of variable diameter. Two or more holes 600 can have the same diameter. Two or more holes can have different diameters. FIG. 31C shows yet another embodiment in which the holes 600 are of variable diameter. The holes 600 can gradually decrease in diameter toward the distal end 160. The holes 600 can gradually decrease in diameter toward the proximal end 132.

[0226] The diameter of the pores 600 may be sized to allow blood to flow in or out of the pores 600. In one embodiment, the diameter or cross-sectional dimension of each pore 600 may be between 25 μm and 400 μm. In another embodiment, the diameter or cross-sectional dimension of each pore 600 may be between 100 μm and 200 μm. In yet another embodiment, the diameter or cross-sectional dimension of each pore 600 may be greater than 8 μm.

[0227] 32A-32C show various examples of axial spacing between holes 600. FIG. 32A shows an embodiment in which the holes 600 are axially spaced on the sheath 120 at substantially uniform axial spacing. The holes 600 can be equally spaced. FIG. 32B shows another embodiment in which the holes 600 are axially spaced on the sheath 120 at various variable axial spacings. The holes 600 can be non-uniformly spaced. FIG. 32C shows yet another embodiment in which the holes 600 are axially spaced on the sheath 120 at variable axial spacings.

[0228] The axial spacing between axially adjacent holes 600 may be any length. In one embodiment, the axial spacing between axially adjacent holes 600 may be between 1 mm and 10 mm. In another embodiment, the axial spacing between axially adjacent holes 600 may be between 1 mm and 5 mm.

[0229] 33A-33C show various examples of radial locations of holes 600. FIG. 33A shows an embodiment in which holes 600 are disposed at substantially uniform radial locations on sheath 120. In one embodiment, the radial variance between axially adjacent holes may be about 0 degrees. Holes 600 can be coaxial. Holes 600 can be along the same circumferential location.

[0230] FIG. 33B illustrates another embodiment in which the holes 600 are disposed at variable radial positions on the sheath 120. The radial dispersion between axially adjacent holes may be any suitable amount between about 0 degrees and 360 degrees. In one embodiment, the radial dispersion between axially adjacent holes may be between about 0 degrees and 180 degrees. In another embodiment, the radial dispersion between axially adjacent holes may be between about 0 degrees and 90 degrees. In yet another embodiment, the radial dispersion between axially adjacent holes may be between about 0 degrees and 45 degrees. The holes 600 may be circumferentially offset. The holes 600 may be disposed along a helix. The holes 600 may be disposed along a helical distribution. The helical distribution may reduce the likelihood of kinking of the outer catheter 36.

[0231] FIG. 33C illustrates yet another embodiment in which holes 600 are present at multiple radial locations at a single axial location on the sheath 120. The holes 600 can be located at two circumferential locations. The holes 600 can be located at three circumferential locations. The holes 600 can be located at four circumferential locations. The holes 600 can be located at five circumferential locations. The holes 600 can be located at six circumferential locations. In one embodiment, the single axial location 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 between two of the aforementioned values. The holes 600 at a single axial location on the sheath 120 can be located at any suitable radial locations. In one embodiment, the holes 600 at a single axial location can be separated by approximately 180 degrees. In another embodiment, the holes 600 at a single axial location can be separated by approximately 120 degrees. In another embodiment, the holes 600 at a single axial location may be separated by about 90 degrees. In another embodiment, the holes 600 at a single axial location may be separated by about 72 degrees. In another embodiment, the holes 600 at a single axial location may be separated by about 60 degrees. Figure 30C shows an embodiment in which there are four holes 600 at a single axial location, each of the four holes separated by about 90 degrees.

[0232] Figures 34A-34C show various non-circular shaped embodiments of holes 600. Figure 34A shows an embodiment in which holes 600 are elliptical. Figure 34B shows another embodiment in which holes 600 are oval. Figure 34C shows yet another embodiment in which holes 600 are rectangular. For example, holes 600 may be shaped and sized to allow blood to flow in and out of holes 600.

[0233] The holes 600 in the sheath 120 may be formed using any suitable method. In one embodiment, the holes 600 may be cut from the sheath 120 using a laser cutting technique. In another embodiment, the holes 600 may be drilled from the sheath 120. In yet another embodiment, the holes 600 may be formed by the structure of the sheath 120.

[0234] While the present invention has been described with reference to particular forms and embodiments thereof, it will be understood that various modifications other than those discussed above may be made without departing from the spirit or scope of the invention as defined in the appended claims. For example, functionally equivalent elements may be substituted for elements specifically shown and described, certain features may be used independently of other features, and in certain cases, the location of certain elements, steps, or processes may be reversed or inserted, all without departing from the spirit or scope of the invention as defined in the appended claims.

Claims

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

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

3. The sheath a proximal section, a distal section, and an intermediate section extending between the proximal section of the sheath and the distal section of the sheath and interconnecting the proximal section of the sheath and the distal section of the sheath; the one or more holes are disposed within the proximal section of the sheath. The intravascular system of claim 1 .

4. The sheath a proximal section, a distal section, and an intermediate section extending between the proximal section of the sheath and the distal section of the sheath and interconnecting the proximal section of the sheath and the distal section of the sheath; one or more holes disposed in the proximal section of the sheath and one or more holes disposed in the distal section of the sheath; The intravascular system of claim 1 .

5. The sheath a proximal section, a distal section, and an intermediate section extending between the proximal section of the sheath and the distal section of the sheath and interconnecting the proximal section of the sheath and the distal section of the sheath; one or more holes disposed in the intermediate section of the sheath and one or more holes disposed in the distal section of the sheath; The intravascular system of claim 1 .

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

7. The intravascular system of claim 1 , wherein the one or more holes are circular in shape.

8. The intravascular system of claim 1 , wherein the one or more holes comprise a plurality of holes, and a single axial location on the sheath comprises the plurality of holes.

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

10. The intravascular system of claim 1 , wherein the one or more holes comprise a plurality of circumferentially arranged holes.

11. The intravascular system of claim 1 , wherein the one or more holes comprise a plurality of longitudinally arranged holes.

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

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

14. The intravascular system of claim 1 , wherein the sheath comprises a solid midsection.

15. The intravascular system of claim 1 , wherein the sheath comprises a non-porous proximal section.

16. The intravascular system of claim 1 , wherein the sheath comprises a non-porous distal section.

17. The intravascular system of claim 1 , wherein the sheath comprises continuous holes.

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

19. The intravascular system of claim 1 , wherein the one or more holes promote perfusion.

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

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

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

Images