FIELD OF THE INVENTION

The present invention is directed to medical devices, and particularly, to minimally invasive devices used for treatments within the human vasculature, such as, for example, coronary arteries.

The present invention is further directed to devices designed for atraumatic, fast, simple delivery and replacement of catheters in coronary arteries or other blood vessels in the human body to facilitate percutaneous revascularization.

The present invention is also directed to medical devices for intravascular procedures using a guide catheter extension system equipped with a delivery micro-catheter that permits easy delivery of the distal portion of the tubular guide extension system to, and beyond, a lesion to be stented (treated).

The present invention further is directed to a medical device that includes a thin-walled tubular guide catheter extension system that is delivered co-axially to, and/or beyond, a coronary artery obstruction lesion by virtue of an integrated micro-catheter system to allow the distal delivery of the guide extension device with minimal trauma while passing through a coronary artery.

The present invention is also directed to a guide catheter extension system operating with a co-axial highly flexible tapered delivery micro-catheter positioned at the distal end and fitted within of the catheter extension system specifically designed to track over a guidewire and configured to deliver the guide extension distal end to, and beyond, a lesion of interest. The guide catheter extension system has a miniature profile (at its distal end) with a diameter less than 1 mm, and equipped with a lubricity coating to permit the distal tip to attain the “crossability” that would be superior to that of the distal tip of a conventional balloon angioplasty catheter, and far superior to the distal tubular end of a conventional guide extension device.

Additionally, the present invention is directed to an intravascular guide catheter extension system using an inner member reciprocable internally of an outer member (a sheath), and configured with a tapered micro-catheter at its distal end. A connection sub-system is provided which controllably connects/disconnects (engages/disengages) the inner and outer member for joined motion within a guiding catheter, or relative displacement of the inner and outer member each with respect to another as required by the intravascular procedure.

BACKGROUND OF THE INVENTION

Coronary artery obstruction disease, or a disease in the peripheral vasculature, is often treated by the balloon angioplasty and/or stent placement. The advancement of the revascularization devices, such as balloons or stent delivery systems, within the blood vessels to a treatment site can be challenging in case of tortuosity and/or calcification of the vessels.

Revascularization devices usually use guiding (or guide) catheters for delivery of such devices to the site of treatment. The use of guide catheters alone to “back up” the advancement of the revascularization devices to the coronary arteries may be limited and challenging.

In order to facilitate the revascularization devices delivery to the site of interest, guide catheter extension systems have been designed and used during cardiac procedures.

For example, the guide extension system, such as “Guideliner™,” is produced by Vascular Solutions. This guide extension system is described in U.S. Pat. No. 8,292,850, authored by Root, et al. Root, et al. (U.S. Pat. No. 8,292,850) and describes a coaxial guide catheter to be passed through a lumen of a guide catheter, for use with interventional cardiology devices that are insertable into a branch artery that branches off from a main artery.

The Root coaxial guide catheter is extended through the lumen of the guide catheter and beyond its distal end and inserted into the branch artery. Root uses the 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 a coronary vessel.

Another guide extension system, such as “Guidezilla™”, has been designed and manufactured by Boston Scientific. This guide extension system is described in U.S. Pat. No. 9,764,118, authored by Anderson, et al. Anderson's guide extension system uses a push member having a proximal portion having a proximal stiffness, a distal portion having a distal stiffness different from the proximal stiffness, and a transition portion disposed and providing 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.

U.S. Patent Application Publication #2017/0028178, authored by Ho, describes a guide extension system using a slit catheter which is extendable upon 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.

The systems, “Guideliner™” and “Guidezilla™”, as well as the Ho's system, support the concept of advancing the guide extension system through the guiding catheter, and partially down the coronary artery, in order to achieve additional “back up” support to deliver balloon dilatation catheters and/or stent delivery catheters to the site of intended treatment.

The function of these guide extensions are to permit closer approach to the lesion to provide additional support in crossing the lesion to be treated with an interventional device. However, despite the additional support, the lesion to be treated can still be difficult or nearly impossible to pass through with a stent delivery system, due to fibrosis, calcification, and/or angulation at the lesion site.

One of the limitations of the currently used guide extension devices is that they use a relatively blunt and large caliber cylindrical distal end. Relatively high profile distal edges have a limited deliverability of the guide extension in many cases, and permit the advancement only to the proximal or mid portion of the coronary artery to be treated. Very rarely, if ever, can the guide extension be delivered to the actual lesion to be treated with angioplasty or stenting, even after balloon pre-dilatation of the lesion.

U.S. Patent Application Publication #2011/0301502, authored by Gill, describes a catheter with a longitudinal separation, allowing for the positioning device to be smaller in diameter than the stent delivery system. The Gill device, however, does not envision an inner catheter to permit easy and atraumatic crossing of the lesion to be treated. The Gill system acts merely as a covering for the stent delivery system, which can be removed after advancement of the stent delivery system, due to the longitudinal separation.

Thus, a device and method that would permit a delivery of the distal portion of the tubular guide extension system to, or ideally, beyond, the lesion to be treated, would have significant advantages over conventional guide extension devices, such as the “Guideliner” (Vascular Solutions), or the “Guidezilla” (Boston Scientific), and others.

It would be highly desirable to provide a guide extension system which can be delivered to the vessel and just beyond the actual lesion, and which would be able to act as a sheathing system to allow rapid delivery of the even long, relatively high profile stent delivery systems to the target lesion.

It would also be highly desirable to provide a placement of catheters into coronary arteries, or other arteries in human body in order to facilitate percutaneous revascularization procedures by using a tapered micro-catheter fitted within the guide extension system to guide the extension distal end to, and past, the lesion to be treated. This would represent substantial improvement upon conventional guide extension systems and which would overcome limitations of such systems.

Although a concept of a tapered piece inside a guide extension catheter is envisioned by Root, this system uses a very short taper, and does not envision the taper as a longer integrated member of the whole system, nor does it envision that this inner piece would travel coaxially over a guidewire. Nor does Root describe, anticipate or envision a longer system delivery system, with a very low profile tip which would be beneficial in attaining the coaxial delivery of the guide extension past a lesion of interest. Such an embodiment has never been commercialized, and the description of the tapered tip inner device was only meant as a means for the proximal delivery of the blunt tip of the guide catheter extension out of the guiding catheter.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a medical device for intravascular application that attains delivery of a minimally traumatic thin-walled tubular guide catheter extension system to, and beyond, a coronary artery obstructive lesion by virtue of an integrated micro-catheter system.

It is another object of the present invention to provide a guide catheter extension system using a coaxial, highly flexible, and removable delivery micro-catheter which is specifically configured to track over a 0.009-0.014″ guidewire, which has a diameter at its distal tip of less than 1.0 mm, and is improved with a lubricity coating which permits the “crossability” of the distal tip that is superior to that of a conventional balloon angioplasty catheter.

One of the objects of the subject invention is to use a highly flexible tapered elongated micro-catheter delivery catheter to deliver the distal tip of a guide extension “sheath” to, and beyond, a target lesion to be treated with angioplasty or stenting in a diseased human coronary artery.

It is an additional object of the present invention to provide a guide catheter extension system in which the total length of the tapered micro-catheter delivery system can extend over 1.5 cm (ideally 2-4 cm) beyond the distal tip of the tubular guide extension system, and which can be movably exchanged within the guide extension system (“sheath”) to allow removal of the micro-catheter delivery piece and exchange for a balloon angioplasty or a stent delivery catheter over the same guidewire that was used to deliver the micro-catheter and guide extension system, which allows easy passage to, and beyond, a lesion of interest in a diseased human coronary artery.

It is a further object of the present invention to provide a guide catheter extension system in which an outer member built with a stent delivery catheter “sheath” is guided over a micro-catheter to be advanced over the micro-catheter delivery catheter beyond a lesion of interest to be treated with balloon angioplasty or stenting. Once the guide extension tip of the catheter “sheath” is advanced over the tapered guide extension micro-catheter delivery catheter to a distal position, a rapid exchange, or alternatively, an over-the-wire inner member (micro-catheter delivery device) is removed, while the 0.014″ coronary guidewire is left in place in the more distal portion of the target vessel, and a treatment catheter may be advanced inside of the “sheath” to the treatment site.

It is an additional object of the present invention to provide a guide extension system configured with the stent delivery catheter “sheath” deliverable to the treatment site inside a vascular structure in an atraumatic manner to attain easy passage of the stent system therethrough. This expedites the cardiac procedure and permits percutaneous coronary intervention to be performed with less radiation dose and with virtually no risk of stent embolization from the stent delivery system.

It is a further object of the present invention to provide a guide catheter extension system in which the tubular sheath of the guide catheter extension system may be formed from or reinforced with a flat wire helical coil (with a wire thickness of approximately 1 mil to 3 mils). Such flat wire helical coil is either embedded in the plastic wall of the sheath, or has a very thin coating of plastic placed onto its inner and outer surfaces. This design reduces the wall thickness of the tubular sheath of the guide extension system to less than 7 mils, and, preferably, to around 5 mils. The micro-catheter at the distal end of the inner member is also envisioned as being formed from or reinforced with the flat wire helical coil, which may have a pitch changing along the micro-catheter length to provide a flexibility gradient beneficial for operation and atraumatic qualities of the subject system. Such a novel construction reduces the outside diameter of the subject guide catheter extension compared to existing guide extension systems.

Furthermore, it is an object of the present invention to provide a guide extension system having a shaft which employs a thin-walled, flat wire helical coil fabricated from a shape memory alloy such as Nitinol to prevent the possibility of kinking of the tubular shaft of the guide extension catheter.

Still another object of the invention is to provide a micro-catheter delivery system that has a balloon on its proximal portion to permit balloon expansion, after it has been advanced into the coronary artery and to an area of interest.

Still another object of the invention is to provide an outer member/sheath whose distal end is tapered, and can be stretched during the withdrawal of the inner member, thus allowing a nearly flush outer surface at the point at which the inner member exits the outer member.

In one aspect, the present invention constitutes an intravascular system equipped with a guide catheter extension sub-system cooperating with a guide wire removably advanceable in a blood vessel of interest to or beyond a treatment site and displaceable internally of a guide catheter.

The guide catheter extension sub-system is configured for controllable displacement along the guide wire. The guide catheter extension sub-system has a proximal portion, a distal portion, and a middle junction portion interconnected between the proximal and distal portions of the guide catheter extension sub-system.

The guide catheter extension sub-system comprises:

(a) an outer member formed by a substantially cylindrically contoured elongated flexible sheath defining a sheath lumen having a proximal end and a distal end. The sheath extends between the middle junction and distal portions of the guide catheter extension sub-system;

(b) an inner member having an elongated body defining an internal channel extending along the longitudinal axis thereof. The inner member extends internally along the sheath lumen in a controllably displaceable relationship with the sheath. The inner member has a distal end configured with a tapered delivery micro-catheter having an elongated body of a predetermined length (preferably, exceeding 2 cm). The tapered delivery micro-catheter is displaceable along the guide wire beyond the distal end of the sheath; and

(c) an interconnection mechanism disposed in an operative coupling with the inner and outer members of the guide catheter extension sub-system and controllably actuated to operate the guide catheter extension sub-system in an engaged or disengaged modes of operation.

In the engaged mode of operation, the inner and outer members of the guide catheter extension sub-system are engaged for a controllable common displacement along the guide wire, and in the disengaged mode of operation, the inner and outer members are disengaged for a controllable individual linear or rotational displacement relative one another.

Preferably, the micro-catheter is formed of a flexible material having differential flexibility along its length. The flexibility of the micro-catheter increases towards its distal end. In one embodiment, the micro-catheter is configured with a flat wire helical coil extending along the predetermined length of the micro-catheter. The pitch of the flat wire helical coil changes along the length of the micro-catheter to increase the flexibility of the micro-catheter towards its distal end.

It is of importance that the predetermined length of the micro-catheter exceeds 2 cm, and a diameter of the micro-catheter at its distal end does not exceed 1 mm.

The sheath, at its distal end, is configured with a tapered outer tip, and the inner member, at its distal end, is configured with a tapered distal tip. The tapered distal tip of the inner member interfaces, at its outer surface, with an inner surface of the tapered outer tip of the sheath. It is of a paramount importance that a dimensional transition between the outer diameter of the outer tip of the sheath and the outer diameter of the distal tip of the inner member does not exceed 0.006″ in order to form a substantially flush transition therebetween and provide a smooth outer surface at the distal portion of the subject guide catheter extension sub-system.

The subject guide catheter extension sub-system further comprises an inner member pusher which is coupled, at its distal end, to a proximal end of the inner member, and an outer member pusher which is coupled, at its distal end, to the proximal end of the outer member. The inner and outer member pushers are actuated by a surgeon (operator) to control the displacement of the inner and outer member along the guide wire, as well as a linear and/or rotational displacement of the inner and outer members relative one another.

The guide catheter extension sub-system further includes an inner member pusher handle, and an outer member pusher handle. The inner member pusher is attached, at its proximal end, to the inner member pusher handle, and the outer member pusher is attached, at its proximal end, to the outer member pusher handle.

The interconnection mechanism in the subject guide catheter extension sub-system is envisioned in a number of alternative embodiments. For example, in one embodiment, the interconnection mechanism is operatively coupled to the inner and outer member pusher handles, and includes tabs extending at opposite sides of one of the inner and outer member pusher handles, and notches formed at respective sides of another one of the inner and outer member pusher handles. The tabs disengageably cooperate with the notches, thus forming a snap-based interconnection mechanism.

In an alternative embodiment, the interconnection mechanism is a friction-based mechanism created between an outer surface of the inner member and an inner surface of the sheath of the outer member at at least one area along their interfacing length.

In yet another embodiment, the interconnection mechanism is configured as a threaded engagement/disengagement mechanism which includes at least one engagement button extending above an external surface of the inner member, and at least one engagement slot configured at least at the proximal end of the sheath of the outer member. The engagement button is removably engaged (by operating the inner and/or outer member pushers) in the engagement slot in the engaged mode of operation for locking the inner and outer member one to another.

In a further alternative embodiment, the subject interconnection mechanism includes:

(a) a pull-away sheath formed with a substantially cylindrically shaped body having a wall defining an internal channel for receiving the inner and outer member pushers therein in the engaged mode of operation. The wall is pre-treated at predetermined areas for collapsing therealong; and

(b) a cord in operative coupling, at one end thereof, with the wall. In the disengaged mode of operation, the cord is pullable to collapse the wall, thus disengaging the inner member pusher from the outer member pusher, for unlocking the inner member from the outer member.

Preferably, the subject guide catheter extension sub-system is configured with a flat wire helical coil member forming at least a portion of respective walls of the sheath and/or the micro-catheter.

The inner member includes, at its proximal end, a tubular member having a proximal opening formed in the tubular member's wall and an internal channel aligned with the inner channel of the inner member. The tubular member of the inner member may include a reinforced portion formed with a flat wire helical coil embedded in its wall and extended circumferentially around the internal channel of the tubular member.

In one implementation of the subject guide catheter extension sub-system, where the inner and outer member pushers are formed as solid wires with tapered distal ends, the guide wire and the tapered distal end of the inner member pusher are received in the internal channel of the tubular member through the proximal opening for extending along the internal channel of the tubular member substantially in parallel relationship.

The distal end of the outer member pusher preferably has a tapered arcuated configuration cooperating with a contour of the inner member at its proximal end. The distal end of the outer member pusher is fixedly attached to the proximal end of the sheath.

The flat wire helical coil which may be embedded in the wall of the tubular member, as well as in the walls of the sheath and/or micro-catheter, is formed of a radio-opaque material, preferably including a shape memory alloy, such as Nitinol.

It is envisioned that radio-opaque markers are attached to the distal ends of the sheath and the micro-catheter to facilitate a surgeon in performing the cardiac procedure.

In another alternative embodiment, the inner member pusher is formed in a tubular configuration having an internal channel extending along the longitudinal axis of the inner member pusher. In this embodiment, the inner member pusher handle includes an entrance channel communicating with the internal channel of the inner member pusher, and the guide wire enters into the internal channel of the inner member at its proximal end through the entrance channel of the inner member pusher handle in communication with the internal channel of the inner member pusher.

In another aspect, the present invention constitutes a method for intravascular treatment using a guide catheter extension system in cooperation with a guide wire and guide catheter. The subject method comprises the following steps:

(a) assembling a guide catheter extension system having:an outer member formed by a flexible substantially cylindrically contoured elongated sheath defining a sheath lumen having a proximal end and a distal end,an inner member having an elongated body defining an internal channel extending along its longitudinal axis. The inner member has a distal end configured with a tapered delivery micro-catheter having an elongated body of a predetermined length (preferably, longer than 2-3 cm). The inner member is extended in the sheath lumen in a controllably displaceable relationship with the sheath, andan interconnection mechanism disposed in an operative coupling with the inner and outer members of the guide catheter extension system and controllably actuated (by a surgeon) to operate the guide catheter extension system in an engaged or disengaged modes of operation.

In the engaged mode of operation, the inner and outer members of the guide catheter extension system are engaged for a controllable common displacement along the guide wire and inside the guide catheter, and in the disengaged mode of operation, the inner and outer members are disengaged for a controllable individual linear and/or rotational displacement relative to one another, as well as for switching between the engaged and disengaged modes of operation.

The method further includes the following steps:(b) upon assembling the guide catheter extension system, extending a guide wire along the internal channel of the inner member with a proximal end of the guide wire extending beyond a proximal end of the internal body, and a distal end of the guide wire extending beyond a distal end of the delivery micro-catheter;(c) advancing the distal end of the guide wire into a blood vessel of interest towards a treatment site;(d) controlling the interconnection mechanism to establish the engaged mode of operation;(e) advancing the guide catheter extension system, in the engaged operational mode, within the guide catheter and along the blood vessel of interest with the micro-catheter sliding along the guide wire towards the treatment site until the micro-catheter is brought at least in alignment with or beyond the treatment site.

The subject method further advances to:(f) controlling the interconnection mechanism to switch to the disengaged mode of operation to disengage the inner and outer members one from another; and(g) subsequently thereto, advancing the sheath (remaining within the guide catheter) along the micro-catheter until the distal end of the sheath is brought in substantial alignment with the distal end of the micro-catheter and is brought in at least alignment or beyond the treatment site.

Subsequent to bringing the distal end of the sheath to a desired position, the subject method continues with the following procedures:(h) removing the inner member from the sheath, yet leaving the sheath inside the blood vessel (within the guide catheter) with the distal end of the sheath in alignment with or beyond the treatment site; and(i) advancing a treatment system (such as, for example, a balloon delivery system or a stent catheter) to or beyond the treatment site inside the sheath lumen for a required treatment of the blood vessel.

These and other objects and advantages of this invention will become obvious to a person of ordinary skill in this art upon reading the detailed description of the subject invention in conjunction with the patent drawings presented herein.

