Patent ID: 12186509

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Depicted inFIGS.1-24B, is the subject intravascular delivery system10which includes a guide catheter extension sub-system (also referred to herein as an outer catheter or an outer member) and an interventional device delivery sub-system (also referred to herein as an inner catheter or an inner member) cooperating under control of a surgeon during a cardiac procedure. Although the interventional device delivery sub-system may be used for delivery of various cardiac interventional devices, in one of the implementations, as an example only, but not to limit the scope of the subject invention to this particular embodiment, the subject interventional device delivery sub-system will be further described as adapted for delivery of a balloon member for performing the pre-dilatation procedure.

In the exemplary embodiment described herein, the subject system10may be referred to herein as a guide catheter extension/pre-dilatation system which may be used for cardiac procedures in conjunction with a guide wire12and a guide catheter14. As shown inFIG.1, at the initial stage of the cardiac procedure, the guidewire (GW)12is moved by a surgeon into the blood vessel16. The guide catheter14is advanced through the blood vessel16(such as, for example, the aorta) along the guide wire12to a position adjacent to the ostium18of the coronary artery20. The guidewire12may be used during the cardiac procedure to guide the guide catheter14, and, subsequently, the subject guide catheter extension/pre-dilatation system10(inside the guide catheter14) may be extended within the artery20toward a target location22, as will be detailed in following paragraphs.

As shown inFIGS.2A-2C, the subject guide catheter extension/pre-dilatation system10includes a balloon catheter sub-system34(also referred to herein as an inner catheter, inner member, or a pre-dilatation sub-assembly) and a guide catheter extension sub-system36(also referred to herein as an outer catheter). The inner catheter34interacts with the outer catheter36and can be engaged with or disengaged from the outer catheter36, as required by the cardiac procedure.

The subject system10includes a proximal section38, a distal section40, and a middle section42extending between and interconnecting the proximal and distal sections38,40. A pre-dilatation balloon member44is carried at the distal section40of the inner catheter34. The distal section40of the inner catheter34also may be configured with an elongated tapered micro-catheter46, as will be detailed in the following paragraphs.

The subject guide extension/pre-dilatation system10, as shown inFIG.1, is extended within a lumen (internal channel)48of the guide catheter14. In order to reliably reach the target location22, and, in some cases, pass beyond the target location22, the subject guide extension/pre-dilatation system10, is advanced through the guide catheter14beyond a distal end50of the guide catheter14deep into the coronary artery20. The subject system10, by extending beyond the distal end50of the guide catheter14, provides an adequate reachability of the pre-dilatation balloon44to the target location22, and, by extending beyond the ostium18of the coronary artery20, stabilizes the positioning of the guide catheter14and allows for an improved accessibility for the subject system10into the coronary artery20and to the target site22.

As shown inFIGS.1,2A-2B,3C-3D,4,5A-5C, and6A, the guide wire12extends internal the guide catheter extension/pre-dilatation system10, and exits the system10with the distal end of the GW12beyond the outermost end52of the distal section40and with the proximal end of the GW12at the middle section42.

In operation, the inner catheter34and the outer catheter36are coupled one to another to be advanced (as a single unit) along the guide wire12inside the guide catheter14positioned within the blood vessel16, and extend beyond the distal end50of the guide catheter14to reach the target lesion site22. Once the subject balloon catheter sub-system (inner member)34reaches the lesion site22, and the balloon member44is positioned in alignment with the lesion site22, the intended pre-dilatation procedure may be performed. Once the pre-dilatation has been performed, the outer catheter (also referred to herein as outer member)36may be advanced across the lesion as an integral unit with the inner catheter (also referred to herein as an inner member)34, with subsequent disengagement of the inner catheter34from the outer catheter36for withdrawal of the inner catheter from the outer catheter.

Alternatively, after the pre-dilatation procedure has been performed, the inner catheter34may be disengaged from the outer catheter36, while the outer catheter36is advanced across the dilated lesion. In addition, the outer catheter36may be left in proximity to the lesion after the pre-dilatation has been performed and the inner catheter34has been removed.

In any case scenario, the outer member (catheter)36remaining in proximity to the pre-dilated lesion may be used for delivery of a stent inside the outer member (catheter)36to the lesion site. The outer member36is removed from the guide catheter14once the stent is installed (deployed) at the lesion site.

As will be presented in further paragraphs, in the subject system, the inner catheter34is prevented from forward displacement inside the outer catheter36. Exclusively a backward or removal displacement of the inner member34relative to the outer member36is permitted to support retraction of the inner member from the outer member subsequent to the pre-dilatation of the lesion.

Referring toFIGS.2A-2C, the proximal section38of the subject guide extension/pre-dilatation system10is represented by a balloon inflation hub56(best depicted inFIG.2B) of the inner member34and a proximal end58of an outer member36.

Referring toFIGS.2B,3A-3D,4, and5C, the inner member (also referred to herein intermittently as the balloon catheter sub-system or pre-dilatation balloon delivery sub-system)34is configured with an internal inflation channel60extending between the inflation hub56and the pre-dilatation balloon member44. The internal inflation channel60serves as a passage for inflation air between a balloon inflation system62(shown schematically inFIG.2B) and the balloon member44for the controlled inflation/deflation of the balloon member44as prescribed by the cardiac procedure.

The internal inflation channel60is formed by an inflation lumen hypo-tube64and an inflation lumen distal shaft66overlappingly interconnected each to the other in a fluidly sealed manner.

The inflation hub56located at the proximal end68of the inner member34is configured with an internal cone-shaped channel70which is connected by its proximal opening72to the balloon inflation system62(as schematically shown inFIG.2B).

The balloon inflation system62may be a manual or an automatic system. In a preferred automatic embodiment, the balloon inflation system62includes an electronic sub-system, a pneumatic sub-system and control software with a corresponding user interface. The electronic sub-system, under control of the control software, supplies power to solenoid pressure valves (which are fluidly coupled to the balloon inflation hub56) to control the pressurizing/depressurizing of the balloon member44with fluid or air flow.

As shown inFIG.2B, the internal cone-shaped channel70of the balloon inflation hub56is configured with a distal opening74which is coupled to the inflation lumen hypo-tube64. The proximal end of the inflation lumen hypo-tube64is coupled to the distal opening74of the internal cone-shaped channel70of the balloon inflation hub56in a fluidly sealed fashion to support passage of the inflation air between the balloon member44at the inflation system62.

The inflation lumen hypo-tube64extends through the length of the proximal section38and a portion of the middle section42of the subject system10and terminates with its distal end78at the distal section40, as shown inFIGS.2B and4.

As shown inFIG.2B, a flexible serrated member80is provided at the proximal end76of the inflation lumen hypo-tube64which is coupled to the distal end82of the balloon inflation hub56. The serrated flexible member80supports the proximal end76of the inflation lumen hypo-tube64and provides a flexible bending of the structure when manipulated by a surgeon.

As shown inFIGS.2A-2C,3A-3D,4and5C, the inflation lumen distal shaft66extends between the proximal section38along the middle section42and ends at the distal section40.FIG.3Adetails the junction between the inflation lumen hypo-tube64and the inflation lumen distal shaft66. The inflation lumen hypo-tube64does not extend all the way through the inner member34but terminates at its distal end78(as shown inFIGS.2B and4).

Referring toFIGS.3B-3D, the inflation lumen hypo-tube64has a skived distal portion90which is coaxially enveloped by the wall of the inflation lumen distal shaft66so that the inflation lumen hypo-tube64, in conjunction with the inflation lumen distal shaft66, provide a sealed fluid communication between the balloon inflation system62and the internal chamber92of the balloon member44, as shown inFIGS.5A-5C, for controlled inflation/deflation of the balloon member44as required by the cardiac procedure.

FIGS.2B and3C-3Dillustrate that the inflation lumen distal shaft66is configured with a rapid exchange (RX) guidewire (GW) port94at which a GW lumen96begins with its proximal end98. The GW lumen96extends between the RX GW port94inside the inflation lumen distal shaft66through the entire length of the distal section40of the inner catheter34. The GW lumen96forms an internal channel with the proximal end98corresponding to the RX GW port94and a distal end100corresponding to the outermost distal end52of the distal section40of the inner member34. As shown inFIGS.6A-6B, at the distal section40, the GW lumen96extends beyond the distal end102of the inflation lumen distal shaft66. The distal end100of the GW lumen96constitutes a gradually tapered portion104which may be in the form of a delivery micro-catheter46.

Referring toFIGS.2A-2B,5A-5C,6A-6B, and24A-24B, the inner catheter (also referred to herein as a balloon catheter sub-system)34is configured with a tapered distal portion (also intermittently referred to herein as tapered distal tip)162at the distal section40. The tapered distal portion162is equipped with the pre-dilatation balloon member44which is secured onto the tapered distal portion162in close proximity to the micro-catheter46. The pre-dilatation balloon member44is secured to the inner member's tapered distal portion (tip)162for supporting the pre-dilatation/stenting procedure, as required for the cardiac treatment of a patient.

The balloon member44has a proximal portion112and a distal portion114. The balloon member44is attached (secured) at the distal section40in proximity to the delivery micro-catheter46with its proximal portion112coupled to the distal end102of the inflation lumen distal shaft66, and with the distal portion114of the balloon44to the outer surface of the micro-catheter46.

As shown inFIGS.5A-5C, the pre-dilatation balloon44is attached, with its proximal portion112, to the proximal portion204of the distal tip162in bordering juxtaposition with the outer tip164of the sheath120, and, with its distal portion114, to the distal end166of the distal portion (tip)162of the inner member34.

The balloon member44may intermittently assume deflated (folded) and inflated (expanded) configurations. The deflated (folded) configuration is used during insertion and/or withdrawal of the subject system relative to the blood vessel. The balloon is inflated (expanded) when in place (at the target site22) to widen the blood vessel and compress the plaque for pre-dilatation procedure, or for the stenting procedure (when a stent is delivered to the treatment site on a balloon). When inflated, the balloon44assumes the inflated/open configuration shown inFIGS.2A-2B,5A,5C,6A-6B, and24A-24Bfor pre-dilatation of the diseased blood vessel. When deflated, the balloon member44assumes the deflated configuration shown inFIG.5B.

The balloon44may have a smooth surface, or a “chocolate” configuration. The “chocolate” balloon catheter is an over-the-wire balloon dilatation catheter with a braided shaft and an atraumatic tapered tip. The balloon, when expanded, is constrained by a nitinol structure that creates small “pillows” and grooves in the balloon.

Referring now toFIGS.2A,2C,5A-5C,7,8A-8B9A,9C-9D,10A-10G,11C,12B-12C,13A-13B,14B,15A-15D,16A-16B,17A-17B,18A-18B,19B,20A-20B,21, and24A-24B, the outer catheter (also referred to as the guide catheter extension sub-system)36is formed with a cylindrical outer delivery sheath120having an internal channel122extending internally therealong. A coupler mechanism130is formed at the proximal end132of the cylindrical sheath120in encircling relationship therewith.

At the proximal end58, the outer catheter36includes an outer member pusher (also referred to herein as a pusher/puller)134, which, as shown inFIGS.10B-10G,11A-11C,12A-12C,13A-13B,14A-14B,15A-15D,16A-16B,17A-17B,18A-18B,19B, and22, in one embodiment, may be a solid wire which may have a round wire proximal section136, and a flattened distal portion138which may be welded or otherwise fixedly attached to the proximal end132of the sheath130. In another embodiment, the pushing and pulling element134may be configured with a hypo-tube.

Alternatively, a round pusher wire can be welded to a flat wire which, in its turn, is welded or otherwise fixedly secured to the proximal end132of the sheath120.

In still another alternative embodiment of the outer member36, a round wire may be welded or otherwise fixedly secured to two flat wires, which in their turn, are welded or otherwise fixedly secured to the proximal end132of the sheath120.

The flattened profile of the pusher wire portion is welded to the proximal coupler130of the outer sheath120so that when the inner member34is inserted in the outer member (catheter)36, the pusher wire does not create an obstacle for the rotational or longitudinal motion of the inner catheter34inside the proximal coupler130and the sheath120of the outer member36, as required by the procedure. The proximal pushing-pulling element134advances with or withdraws the outer tubular sheath120and is preferably flexible (not rigid). The pusher/puller134may be flexible (not rigid) with the flexibility along its longitudinal axis being comparable or exceeding the flexibility of the tubular outer delivery sheath120of the outer catheter36.

The outer catheter's pusher134may be equipped, at the proximal end thereof, with a proximal handle140, shown inFIG.10F, for convenience of a surgeon performing the coronary intervention procedure for manipulation of the outer member36in order to position the outer delivery sheath120along with the balloon delivery sub-system34, at the desired location relative to the lesion22in the diseased blood vessel.

The proximal (wire or hypo-tube configured) pushing/pulling element134connected to the outer member's tubular structure120, by having a miniature profile and being flexible (not “rigid”), attains an enhanced conformability inside the guiding catheter and a lower profile than the rigid “pushing” elements in conventional guide extension catheters (as per Root). This is made possible due to the “pushability” of the “system as a whole”, attained via the locked integral connection between the outer catheter (with its hypo-tube pushing element) and the inner catheter (guide extension tube).

In addition, the inner catheter (inner member)34may be equipped with an inner member's pusher (also referred to herein as a pusher/puller)142(shown inFIG.2A) which may be attached to the inflation hub56to facilitate the withdrawal of the inner member34from the outer member36as required by the coronary intervention procedure, as well as for controlling engagement/disengagement therebetween, for various stages of the cardiac procedure. The inner member's pusher/puller142may be formed with an inner member pusher/puller's handle for convenience of a surgeon performing the procedure.

The handles of the inner and outer members' pushers may be configured with a mechanism (detailed in the U.S. patent application Ser. No. 15/899,603 which is hereby incorporated by reference) which permits an additional releasable locking of the inner and outer members one to the other to enhance the integral cooperation thereof in an engaged mode of operation.

The inner member34may be either of the over-the-wire configuration or of the RX configuration. In one of the embodiments detailed herein, the guide wire12extends through the RX GW port94made at the proximal end of the tubular inflation lumen distal shaft66into and along the internal channel146of the GW lumen96, as shown inFIGS.3C-3D, and4. At the distal section40of the subject system10, the guidewire12extends in the GW lumen along the delivery tapered micro-catheter46(at the tapered portion104), and exits at the distal ends100of the GW lumen96at the outermost end52of the inner member34, as shown inFIGS.2A-2B,5A-5B, and6A-6B.

The outer delivery sheath120of the outer member36is fabricated with a flexible cylindrically shaped tubular body150extending substantially the length of the middle section42of the subject system10. By manipulating the outer member pusher134, a surgeon actuates the integral advancement of the outer delivery sheath120and the inner member34along the guide catheter14. When the pre-dilatation procedure has been performed (as will be detailed in further paragraphs), the surgeon controls a required linear backward displacement of the inner member34with regard to the sheath120of the outer member36by manipulating the outer member pusher134and/or the inner member pusher142.

The interface between the outer tip164of the sheath120and the distal tip162of the inner member34, as shown inFIGS.8A-8B and9A-9D, facilitates displacement of the distal tip162of the inner member34relative to the outer tip164of the sheath120and basically facilitates displacement of the distal tip162relative to the outer tip164of the sheath120as required by the cardiac procedure.

The distal end160, as well as the outer tip164of the sheath120, is formed of a flexible material which permits a simplified retraction of the distal tip162of the inner member34therethrough. The flat wire helical coil may be used for the distal end160and the outer tip164of the sheath120.

At its proximal end132, the sheath120of the outer catheter36, is configured with an entrance “opening” (or a “mouth”)210the circumference of which exceeds the circumference of the outer member flexible tubular sheath120, as shown inFIGS.10A-10G. The entrance210(also referred to herein as a “mouth”) into the internal channel122of the sheath120may be configured in various modifications. For example, as shown inFIG.10A, the entrance210has a funnel shape211with an eccentric opening (as shown inFIG.10A), or contoured with a concentric blunt (as shown inFIGS.10B-10C), or with a concentric bevel (as shown inFIGS.10D-10E), or alternatively, with the concentric concave contour (as shown inFIGS.10F-10G). The pusher134is affixed at a predetermined point of the funnel shape outer catheter's proximal entry210.

As shown inFIGS.2A,2C,7, and8A-8B, the outer delivery sheath120of the outer catheter36extends between its proximal end132at the middle section42and its distal end160at the distal section40of the subject system10. At the distal section40of the subject guide catheter extension/pre-dilatation system10, the inner member34is configured with a tapered configuration104having a distal tapered portion (also referred to herein as a distal tapered tip)162which may be formed with the micro-catheter46, as shown inFIGS.2A-2B,5A-5B,6A-6B,8A,22A-22B, and24A-24B. The micro-catheter46is an elongated thin member with the length in a cm range, for example, 1-3 cm. The micro-catheter46has a tapered cone-contoured configuration with the diameter not exceeding 1 mm at its distal end52. The micro-catheter46may be formed integrally with the tapered distal tip162of the inner member34.

As shown inFIGS.2A,5A-5C,7, and8A-8B, at the distal end160, the outer delivery sheath120is formed with an outer tip164which has a tapered cone-contoured configuration which may be interconnected with the distal tip162of the inner member34. The outer tip164of the outer member36provides a smooth distal taper transition between the distal end160of the sheath120and the distal section40.

InFIGS.2A,5A-5B,6A-6B,8A-8B,22A-22B, and24A-24B, the distal tip162of the inner catheter34is shown to have a tapered configuration which changes gradually from the point of interconnection with the outer tip164of the sheath120to the distal end166of the distal tip162. The micro-catheter46extends from the distal end166of the distal tapered portion162of the inner member34(the length of about 1-3 cm) in an integral connection therewith and terminates in the outermost distal end52.

The subject guide catheter extension/pre-dilatation system10may be configured with a differential in micro-catheter flexibility with greater flexibility in the distal portion, by either changing the durometer of the plastic (polymeric) components from the outer delivery sheath's proximal portion to its distal portion (i.e., a higher durometer in the proximal portion when taken with respect to the distal portion), and/or changing the winding frequency (pitch) of the helical coil of wire in the micro-catheter46in the direction from the proximal portion to distal portion, such that the distal portion of the micro-catheter46is more flexible and trackable than the proximal portion of the micro-catheter delivery device, with a substantially lower profile and is more flexible than the distal portion of the guide catheter extension sub-system (outer delivery sheath).

The system10may also include wires that have radio-opacity such that the balloon member44, micro-catheter46, and the outer delivery sheath120are easily visualized using fluoroscopy. It is envisioned that the distal tip162(as shown inFIGS.5A,6A-6B) is provided with radio-opaque markers264,266in proximity to the proximal portion112and the distal portion114of the balloon44. The radio-markers264,266permit the surgeon (operator) to visualize positioning of the balloon member44relative to the lesion location22.

In addition, the outermost distal tip52of the micro-catheter delivery portion46and the tip160of the sheath120may have one or more radio-opaque markers268,270(shown inFIGS.2B and5A) in order to permit the surgeon to distinguish between the radio-markers, which is particularly important as the obstructive lesion is passed by the micro-catheter, and the balloon member carried in proximity to the micro-catheter is held in place.

As detailed inFIG.7, in one embodiment thereof, the outer catheter36is configured with a system of catheter shaft coil reinforcement170disposed on (or embedded in) the internal surface152of the sheath120. Preferably, a lubricious liner172is positioned inside the shaft120. The shaft reinforcement coil170may be installed inside the shaft120in contact with the lubricious liner172, i.e., in encircling relationship with the surface of a lubricious liner172which covers the inner surface152of the shaft120. A distal soft tip jacket174is affixed at the distal end of the outer catheter shaft120along the longitudinal axis176of the outer catheter36.

The distal soft tip jacket174may be glued to the shaft120at the end175(as shown inFIG.7), or may cover some length of the outer surface173of the shaft120.

The distal soft tip jacket174extends at the distal end160of the shaft120beyond the coil reinforcement170and the lubricious liner172, and terminates in the tapered portion178, which has a distal edge184and a proximal edge182.

The lubricious liner172may be formed from the PTFE material. The distal soft tip jacket172may be formed of a very flexible low durometer elastomeric Pebax material which transitions into high durometers along the longitudinal axis176towards the proximal end132of the sheath120.

As shown inFIGS.7and8A-8B, in one of the preferred embodiments, the internal diameter of the sheath120at its inner surface152is approximately 0.048″, while the outer diameter of the shaft120at its outer surface173is 0.058″. The internal diameter of the tapered portion178of the outer catheter36at the distal edge184is 0.045″, while the outer diameter of the tapered portion178at its distal edge184is 0.047″. The gradient between the outer diameter (0.058″) of the sheath120and the outer diameter of the taper178(0.047″) define the outer surface tapering, while the gradient between the inner diameter (0.048″) of the sheath120at the inner diameter (0.045″) of the taper178at its distal edge184define the tapering of its inner surface. The distal wall180of the tapered portion178has a thickness reduction from the interface182(between the sheath120and the tapered portion178) to the outermost edge184of the tapered portion178of the distal soft tip jacket174.

As shown inFIG.7in conjunction withFIGS.8A-8B, the outer diameter of the inner catheter's tapered element104has the outer diameter approximately 0.046″ which is approximately 0.001″ larger than the outer catheter's distal tip internal diameter (0.045″) at the outermost distal edge184. This difference between the outer diameter of the tapered element104of the inner catheter34and the inner diameter at the distal edge184of the outer catheter's outer tip164results in stretching of the distal soft tip jacket174at the tapered portion178thereof when interfering with the inner catheter's tapered element104. Such arrangement provides for a near seamless transition between the distal tip of the inner catheter34and the distal tip of the outer catheter36, as well as a miniature profile of the distal end due to the squeezing of the distal tip of the inner catheter34by the tapered element178of the outer catheter36. Upon removal of the inner catheter34, the distal tip of the elastomeric properties of the distal soft tip jacket174of the outer catheter36permit the tapered portion178to return to its original internal diameter (0.045″).

In the disengaged mode of operation, said inner diameter of the wall180of the tapered outer tip164of the outer member36is smaller than the outer diameter of the inner member34. In the engaged mode of operation, the tapered outer tip164of the outer member36and the inner member34interact such that a dimensional transition between the outer diameter of the tapered outer tip164of the sheath lumen120and the outer diameter of the distal portion of the inner member34forms a substantially flush interface transition therebetween.

Referring further toFIGS.9A-9D, the tapered portion178is contemplated in several embodiments of the expandable tapered designs. As shown inFIG.9A, the elasticity of the outer catheter36at its distal tapered portion178is augmented by an expandable split ring190affixed at the tapered portion178which allows the distal outer tip164to expand (when interfaced with the inner catheter34). The expandable split ring190has a slit192which allows the ring190to expand and contract, depending on the interference between the inner and outer catheters at their distal ends. This structure provides an additional reinforcement to prevent a permanent deformation of the tapered portion178during the inner catheter34removal and delivery of the stent (or the balloon).

Referring toFIG.9B, in an alternative embodiment of the outer catheter36, the tapered portion178may be configured with an expandable tip scaffold194which may be fabricated from NiTi wire and configured with a distal end196and a proximal end198which has a diameter larger than the diameter of the distal end196. Due to its flexibility, the expandable scaffold194, expands and contracts, when needed, and provides additional support to resist a permanent deformation of the jacket174at the tapered portion178during the inner catheter removal and delivery of the stent or the balloon member.

Another alternative embodiment of the tapered portion178at the distal end of the sheath120is shown inFIGS.9C-9D, where wall180of the tapered portion178is shaped with slits200which extend longitudinally along the length of the tapered portion178spread apart along its perimeter. When the tapered portion178interfaces with the distal end of the inner member34, the slits200temporarily widen to embrace the distal tip162of the inner catheter34. This design can prevent a permanent deformation of the jacket174at its tapered portion178which may be caused by the inner catheter34removal or during the stent/balloon number delivery.

An important “seamless” aspect of the subject system is that for a transition between the outer diameter of the outer tip164of the sheath120(at the tapered portion178thereof) and the outer diameter of the distal tip162of the inner member34forms substantially gradual (smooth) transition therebetween.

As shown inFIGS.2C,10A-10G,11A-11C,12A-12C,13A-13B,14A-14B, and15A-15D, the subject system is built, at the middle section42, with an interconnection mechanism220which includes the proximal coupler130formed at the proximal end132of the sheath120of the outer member36, and a cooperating mechanism222formed at the outer surface of the inner member34(as depicted inFIGS.17A-17B,18B,19A-19B, and20A-20C).

The subject guide catheter extension/pre-dilatation system10may operate in an inner/outer catheters engagement mode and in an inner/outer catheters disengagement mode, which is accomplished by controlling the interconnection mechanism220. The subject interconnection mechanism220is configured to engage/disengage the inner and outer catheters34,36(as required by the cardiac procedure), as well as to prevent an unwanted forward displacement of the inner member34inside the outer delivery sheath120. The engagement mode of operation allows the enhanced “pushability” of the “system as a whole” (with the outer catheter36connected and locked to the inner catheter34) even with the connected pushing/pulling element134of the outer member36configured as a low profile and flexible element (as flexible or more flexible than the outer tubular sheath120of the outer catheter36).

The interconnection unit220operates based on the interference between the proximal coupler130configured at the proximal end132of the sheath120and the cooperating mechanism222configured at the outer surface224of the inner member34when the inner surface152of the tubular body150of the sheath120(at its proximal end132) engages the outer surface224of the cooperating mechanism222(on the inner member34).

As an example, a number of interconnection mechanisms are envisioned to be applicable in the subject guide catheter extension/pre-dilatation system10. The subject engagement mechanism is configured for controllable engagement/disengagement between the inner member34and the outer member36, as well as to prevent a forward motion of the inner member34relative the outer delivery sheath120beyond a predetermined position.

For example, as depicted inFIGS.11A-11C, a laser cut coupler130may be configured with a proximal open (split) ring240and a pair of distal rings including a solid distal ring242and an open (split) distal ring244. The proximal open ring240, as well as the distal rings242and244, is formed integrally with a coupler base246. The coupler130may be formed from stainless steel or heat set NiTi. The pusher/puller element134of the outer catheter36and the mid-shift coupler (also referred to herein as a proximal coupler)130may be made from a memory metal (such as, for example, nitinol) so as to prevent deformation during antegrade or retrograde movement of the outer member and to prevent any deformation of the mid shaft coupler130during the stent (or other device) passage through the mid shaft portion of the outer catheter36.

The open ring240is correlated with the proximal entry opening, (for example funnel shaped)211of the outer catheter36(shown inFIGS.10A,10D-10E and11C). The proximal open ring240allows for expansion of the entrance211into the funnel210as needed for entrance/removal of the inner catheter34as required by the surgical procedure. As shown inFIGS.10A,10D-10E, and11A-11C, the proximal open ring240provides a support for the proximal opening210of the funnel shaped proximal end of the sheet120. The proximal ring240reinforces the entrance opening (“mouth”)211and prevents from the damage or a permanent deformation of the entrance opening, thus supporting elastic properties of the sheath120at the entrance opening210. The distal rings242,244create a snap-fit lock mechanism separate from the funnel's proximal open ring240. The distal ring242is not expanded (being of a closed circular contour), while the opening of the split ring244expands during the displacement of the inner catheter34relative to the proximal coupler130of the outer catheter36.

The base246of the coupler130, as shown inFIGS.11B-11C, may be flat, or preferably, is slightly arcuated (in the cross-section) to be congruent with the cooperating distal end250of the pusher134which has either flat or crescent (in crossing direction) contour. The pusher134may be fabricated from stainless steel or NiTi. The distal end250of the pusher134is welded (glued, adhered or otherwise affixed) to the base member246of the coupler130. The PTFE liner (also shown inFIG.7)172may encapsulate the coupler130as shown inFIG.11C.

The sheath120is positioned in surrounding relationship with the coupler and the PTFE liner172. The Pebax encapsulation, similar to the distal soft tip jacket174, at the distal end160of the sheath120(shown inFIG.7) may be used at the proximal end132of the sheath120. The catheter shaft coil reinforcement170(also shown inFIG.7) at the distal end of the outer catheter36can extend the length thereof to the proximal end of the outer catheter36.

As shown inFIGS.11A-11C, and17A-17C, and18A-18B, cooperating mechanism222for the specific embodiment shown inFIGS.11A-11Cfurther includes a mid-shaft lock ring252(shown inFIGS.17B-17C and18B) for the snap-fit locking.

Another embodiment of the outer catheter's proximal entry structure shown inFIGS.12A-12C, is similar to the one shown inFIGS.11A-11Cwith certain modifications, including:(a) an added thickness and additional material around the base246of the coupler130;(b) modified surface treatment (e.g., bead blasting) for improving the polymer encapsulation adhesion; and(c) using the hard polymer (such as Nylon) encapsulation to provide additional support to the funnel to prevent damage which may impede the stent passage.

An additional embodiment of the coupler130at the proximal entry210(shown inFIGS.13A-13B) features open rings (ribs)256which reinforce the entrance port210. The snap-fit lock260is represented by at least two open rings262at the distal end of the coupler130. The coupler130, as shown in the modification presented inFIGS.13A-13B, is preferably a laser cut coupler formed either from a stainless steel or heat set NiTi.

The hypo-tube pusher/puller134may be flattened at its distal end250and is welded to the base246of the coupler130. The PTFE liner172extends underneath the coupler130, and the Pebax encapsulation174envelopes the coupler130with the pusher134affixed thereto. The catheter shaft coil reinforcement structure170extends along the shaft120of the outer catheter36from the distal to the proximal end thereof. The snap-fit lock260cooperates with the round ring embodiment of the cooperating mechanism222shown inFIGS.17A-17C and18B. In some embodiments, the encapsulation174and/or the pusher/puller134may be color coated with a distinct color, as shown inFIG.11A, to distinguish the outer member's pusher/puller134from other elements of the subject arrangement for the surgeon convenience and safety of the procedure.

An additional modification of the coupler130is presented inFIGS.14A-14Bwhere the coupler130has individual rings266,268welded to the distal end250of the pusher134. As shown, the locking mechanism260is formed by the solid distal ring266, and the mid split ring268, with each ring266,268welded to the pusher134. The proximal bevel split ring270is also welded to the pusher134. This design offers an increased flexibility in terms of the size and configuration of each ring266,268and270, and supports the formation of different funnel shapes/dimensions, as opposed to the laser cut coupler limited to a single diameter.

FIGS.15A-15Bdepict another modification of the proximal coupler130which features funnel fenestrations which improve the contrast infusion flow rate by providing an additional open cross-sectional path for the fluid flow. As shown inFIGS.15A-15B, circular openings272are formed in the sheath120. The openings272are positioned in a predetermined pattern in a non-obstructive fashion with the proximal split ring274and the distal rings276,278of the snap-fit lock structure280. Shown inFIGS.15C-15D, the coupler130is formed with triangular openings282formed in the sheaths120in the non-obstructive fashion with the proximal ring274and distal rings278,276of the snap-fit lock280.

Although only circular and triangular openings272,282, respectively, are shown inFIGS.15A-15D, other configurations of the cutouts in the plastic encapsulation are also contemplated in the subject structure to allow the passage of an injected contrast fluid through the cutouts.

Referring toFIGS.16A,16B, and16C, another embodiment of the proximal end of the outer catheter36is presented which is specifically designed as a potential solution to prevent an unwanted embolization situation when air is inadvertently entered with the fluid injected between the inner and outer catheters34,36. In order to prevent this, a flush lumen290is built into the pusher134via a flattened hypo-tube. A Luer hub is coupled to the proximal end of the hypo-tube (pusher134) as shown inFIG.16C, so that a surgeon can inject the fluid between the inner and outer catheters via the hypo-tube134. When the fluid is entered into the outer catheter lumen292via the channel290in the hypo-tube134, the entrance of air bubbles between the inner and outer catheters is prevented.

Further, referring toFIGS.17A-17C, the interconnection unit220between the proximal coupler130presented inFIGS.11A-11E,12A-12C,13A-13B,14A-14B, and15A-15D, includes the cooperating member222in the form of an annular round ring252(also referred to herein as a mid lock ring) formed on the outer surface224of the inner catheter34. The stainless steel annular ring252is contoured with a full round surface which permits for smallest reversible engagement/disengagement from the need split-ring feature of the outer catheter coupler130. The ring252as shown inFIG.17Chas a rounded contour on the outer surface302for smooth locking/unlocking action. The inner surface304of the ring252is also a smooth structure which is engaged with the outer surface224of the inner catheter34.

FIG.17Adepicts the disengaged configuration of the inner catheter34relative to the outer catheter36.FIG.17Bis representative of the lock engaged configuration when the inner catheter34is received and locked inside of the opening210at the proximal end of the sheath120so that the ring252is engaged in the snap-fit lock306formed by the distal solid ring308and the mid split ring310. While in position, the proximal bevel split ring312encircles the inner catheter34, and the ring252is locked in the snap-fit lock306, thus engaging the inner and outer catheters for surgical manipulation as required by a surgical procedure.

During the longitudinal motion of the inner catheter34inside the outer catheter36, while the ring252passes through the proximal bevel split ring312and the mid split ring310, the arms of these rings are expanded from the original position to create a sufficient room for the ring252to pass. When in position, i.e., the ring252is received between the rings308and310, the arms of the bevel split ring312and the split ring310return to their original closed position. The ring252, being trapped between the rings308,310, is snap-fit locked therebetween, thus preventing the inner and outer catheters relative displacement.

Referring toFIGS.18A-18B, detailing the structure shown inFIGS.17A-17C, it is shown that the section (pocket)316of the sheath120of the outer catheter36is not reinforced by the coils170and deflects when the mid shaft lock ring252is inserted between the solid distal ring308and the mid split ring310of the snap-fit lock306. The deflected portion316of the sheath120between the rings308and310provides additional retention force to maintain the inner and outer catheters34,36in locking engagement.

The stainless steel annular ring252may be attached to the outer surface224of the inner catheter shaft34via an adhesive. The lock ring geometry (full round surface) allows for a smooth reversible engagement/disengagement from the laser cut features of the outer catheter's coupler130. The distal ring308of the snap-fit lock306prevents further distal motion of the inner catheter34, while the mid-split ring310opens upon contact with the mid shaft lock ring252and provides the tactile snap. The proximal bevel split ring312allows for the funnel211to be opened to an internal diameter larger than the internal diameter of the rest of the shaft120. It also allows for a smooth passage of the mid-shaft lock ring252.

The interference between the unreinforced shaft pocket316and the mid shaft lock ring252provides retention of the inner catheter34to the outer catheter36until the user is ready to remove the inner catheter34from the outer catheter36, thus disengaging the snap fit lock therebetween. The force required to disengage the lock mechanism can be tailored from 0.1 to 2.0 lbs.

Referring toFIG.19A-19C, another alternative embodiment of the mid shaft lock is presented which includes a square annular ring (formed of a metallic or a polymeric material)320. Unlike the ring252, shown inFIGS.17A-17C and18B, the ring320has a square cross-section321, shown inFIG.19C. The square annular ring320is affixed to the outer surface224of the inner catheter34with a heat fused Pebax encapsulation322. Alternatively, it may be glued to the inner catheter outer surface224. As shown inFIG.19B, when the inner catheter is in locked position, the square annular ring320snaps into the snap-fit lock324formed by the solid ring326and split ring328, with the encapsulation322in contact with the internal surface152of the sheath120and with the ring320positioned between the rings326and328.

In a further alternative embodiment, shown inFIGS.20A-20C, the mid-shaft lock mechanism220is formed with the cooperating member222in the form of a cage shaped structure330having two NiTi rings332,334connected together through a number (for example, 4) of NiTi shape-set wires336. As shown inFIG.20A, the cage330is affixed to the outer surface224of the inner catheter34either by gluing or by heat fused Pebax encapsulation338. Each of the wires336has an arcuated extending portion340which is left free from the encapsulation338as shown inFIGS.20A and20B.

As shown inFIG.20B, for the locking configuration, the cage structure330snaps into the outer catheter's coupler130. The un-encapsulated arcuated portion340of each wire336extends outside the encapsulation338and away from the wires336of the cage330. When the cage330is received between the rings342and split ring344of the snap fit mechanism346, the locking mechanism346is actuated, and the inner and outer catheters34,36are engaged.

Referring further toFIG.21, the proximal coupler130of the outer catheter36may include two locking slots350,352which are formed by connected rings354and356with a connecting element358.

Referring toFIGS.17A-17C,18A-18B,19A-19B,20A-20C, as well as10A-10G,11A-11C,12A-12B,13A-13B,14A-14B,15A-15D, and21, when a surgeon linearly displaces the inner member34within the internal channel122of the proximal coupler130, the snap-fit annular ring252,320, or the cage330enters the channel122between the arms of the proximal ring240,312, which are flexibly bent outwardly to permit forward motion of the inner catheter34(towards the distal tip162). When the snap-fit annular ring252,320or the cage330passes further through the mid split ring244,262,268,310,328of the snap-fit lock, the arms of the bevel proximal ring return to their original position, but the arms of the mid split ring are flexibly bent outwardly to allow the ring252,320of the cage330to the position between the distal solid ring and the mid split ring. After the ring/cage252,320,330is snap-fit between the rings of the snap-fit locking mechanisms, the arms of the mid-split ring return to their original position.

In order to disengage the inner member34from the outer member36, the surgeon pulls the inner member34from the internal channel of the proximal coupler130. During the removal of the snap-fit annular ring/cage252,320,330from the channel, the pulling action causes the arms of the mid-split ring to bend outwardly to permit the passage of the snap-fit annular ring/cage252,320,330therebetween, thus freeing the inner catheter34from the proximal coupler130of the outer catheter36.

Returning toFIG.3D, the inflation lumen distal shaft66at the middle section42of the subject guide catheter/pre-dilatation extension system10may be manufactured with braid reinforcement structure260. The braid reinforcement member260creates a somewhat flexible tubing connected to the cooperating mechanism222of the interconnection unit220of the inner member34. The RX (Rapid Exchange) port94for passing the guide wire12may be formed through the wall of the braid reinforced inflation lumen distal shaft66.

The braid reinforcement structure260may be configured with metallic patterns or wires within the braid reinforced inflation lumen distal shaft66to prevent kinking, which would give the shaft66a longitudinal stiffness. The metal braid260may be embedded in the braid reinforced shaft66to add increased flexibility thereto required for retraction of the inner member34relative to the outer delivery sheath120during the procedure.

A flat wire helical coil (made, for example, from a shape memory alloy, such as Nitinol) with a wire thickness of approximately 1 mil to 3 mils may be embedded in the braid260. This coil may be formed with a very thin coating of plastic placed onto its inner and outer surfaces, which facilitates the reduction of the wall thickness of the inflation lumen distal shaft66to less than 7 mils and preferably to approximately 5 mils.

The principles of reinforcing the tubular members by the catheter shaft coil reinforcement170in a form of a flat wire helical coil262or forming the tubular members from the flat wire helical coil may be applied in the subject guide catheter extension/pre-dilatation system10to the outer delivery sheath120(as shown inFIGS.7,8B,9A-9D,10A,11C,12B-12C,13A-13B,14B,15A-15C,16A-16B,17A-17B,18A-18B,19B,20B, and21, as well as to the micro-catheter46(as shown inFIGS.2A-2B,5A,22, and24A-24B). In the outer delivery sheath120and/or the micro-catheter46, such flat wire helical coil may be embedded in predetermined positions along the length of the walls thereof, for example, at the proximal and or distal ends.

Alternatively, the entire length of the outer delivery sheath120and/or micro-catheter46may be formed with the flat wire helical coil. The pitch between the coils may be adjusted to provide the flexibility gradient along the length of the tubular member (sheath120and or micro-catheter46) increasing towards the distal end thereof to facilitate atraumatic operation.

Referring toFIGS.22A-22B and23A-23C, rather than utilizing a standard over-the-wire (OTW) guidewire lumen, a monorail Rapid Exchange (RX) design of the inner catheter34′ may be implemented to allow for the use of short guidewires. In the embodiment shown inFIGS.22A and22B, which represent the isometric view of the subject coil reinforced inner member shaft400and the side view taken along lines A-A thereof, the distal section40′ of the inner member34′ includes a tapered element402attached to the outer surface224of the inner member34. The outer shaft400of the inner member34′ is a coil reinforced with coil reinforcement structure404extending from the distal tip406to the RX entry port94shown inFIGS.2A-2C and3C-3D. The distal tip406is a tapered soft tip which, along with the tapered element402, interfaces with inner surface of the outer catheter36when the inner catheter34′ is charged in the outer catheter36, as required by the surgical procedure.

The distal section40′ contains a concentric guidewire lumen408, which communicates with the RX entry port at the proximal end of the inner catheter34(shown inFIGS.2A-2C, and3C-3D).

Shown inFIGS.23A-23C, the proximal end412of the monorail micro-catheter embodiment shown inFIGS.22A-22Butilizes a skived hypo-tube pusher414. The proximal end412of the coil reinforced inner member shaft416and the hypo-tube pusher414are encapsulated in the proximal outer jacket418, which extends as a tube along the proximal end412of the monorail micro-catheter embodiment of the inner member34′, from (and including) the coil reinforced inner member shaft416(which serves as a guidewire lumen)408shown inFIGS.22A-22Band the hypo-tube pusher414.

The embodiment depicted inFIGS.23A-23Bfeatures an RX guidewire “notch” termination/entry420which is fabricated by piercing the proximal outer jacket418. Subsequently, the coil reinforced inner member shaft416is inserted into the proximal outer jacket tube418via the RX entry “notch”420. The skived hypo-tube415is further inserted into the proximal outer jacket tube418via its lumen422, and the polymers of the coil reinforced inner member shaft416and the proximal outer jacket tube418are fused together to connect the inner member shaft416and the pusher414and, thus, to form the proximal end412of the monorail micro catheter inner member34′.

For convenience of the surgeon, the pushing/pulling element134of the outer catheter36may be colored (color coated), as shown inFIG.11A, to have a distinguished color to differentiate it from other elements of the system, such as the pushing/pulling element of the inner catheter34, as well as from the usual gray or silver color of a coronary guidewire used to deliver the device or a stent delivery system. Alternatively, the proximal outer jacket418of the pushing-pulling element414may be color coated to distinguish its color from the colors of other elements in the subject system.

Referring further toFIGS.24A-24B, representative of an additional coil reinforced balloon catheter embodiment 500 of the inner catheter, the structure combines the reinforced shaft properties of the micro-catheter46with that of the dilatation balloon44with the following attributes:a. Coil reinforced shaft502provides an additional kink resistance and pushability while still maintaining flexibility for navigating tortuous vasculature; andb. The structure's longer distal tip504contains low profile, tapered soft tip to facilitate crossing the stenosis and tight lesions.

As shown inFIGS.24A-24B, the distal section504of the subject structure500includes the inner member shaft500reinforced with the coil reinforcement structure506which extends the length of the inner member's shaft500. The distal tapered element508is positioned on the inner member shaft500and extends between the ends510and512in encircling relationship with the inner member shaft500. The distal tapered soft tip514may be in the form of the micro catheter46which is positioned at the end of the coil reinforced shaft500.

Similar to the embodiment presented inFIGS.22A-22B, the balloon member44is positioned on the inner member shaft500with the radio opaque markers264and266positioned on the inner member shaft500within the balloon member44. At its proximal end516, the balloon member44interferes with the outer tip164of the proximal tapered element178of the outer member sheath120. At the distal end518, the balloon member44snugly embraces the shaft500.

Returning toFIGS.1-24B, in operation, for performing the cardiac procedure, and specifically the pre-dilatation routine, a proximal end of the coronary guidewire12is entered into the RX port94formed in the inflation lumen distal shaft66, and is extended through the inner channel (GW lumen96) of the inner member34towards and beyond the outermost distal end52of the micro-catheter46. Subsequent thereto, the guide catheter14is advanced into the blood vessel16of interest.

Subsequently, the outer delivery sheath120of the outer member36locked with the inner member34therewithin, are placed first with the micro-catheter46in the internal channel48of the guide catheter14, and both inner and outer members34,36as a single unit, are integrally advanced within the guide catheter14towards the treatment site22. The outer member's sheath120and the inner member34may be integrally displaced by pushing the outer member pusher134. This action causes the micro-catheter46of the inner member34to slide along the GW12along with the outer member36until they extend beyond the distal end50of the guide catheter14, and reach the lesion site92. In this step of the procedure, the balloon member44is in its deflated configuration.

The guidewire12which extends beyond the distal end50of the guide catheter14, serves as a guide along which the micro-catheter46(with the deflated balloon44attached to the distal tip162) slides towards the treatment site26.

Subsequently, the balloon member44(which is positioned at the treatment site22) is inflated by the balloon inflation system62connected to the inflation hub56through the inflation lumen formed by the inflation lumen distal shaft66and the inflation lumen hypotube64in order to compress the plaque and to widen the blood passage inside the blood vessel16.

Subsequently, once the lesion has been dilated, the balloon44is deflated, and the outer delivery sheath120may be advanced across the lesion22either as an integral unit with the inner member34(in the engaged mode of operation), and the inner member may be subsequently disengaged (unlocked) from the outer delivery sheath120and removed from the sheath120.

Alternatively, the inner member34may be disengaged and withdrawn from the sheath120directly after the lesion dilatation, while the outer member36is advanced across the lesion22.

The sheath120may be left in place (directly after the dilatation of the lesion) proximal to the treatment site.

Subsequent to pulling the inner member34, the stent can be delivered to the site22. The stent, in its closed configuration, may be introduced into the blood vessel16inside the sheath120. When in place, the stent supporting balloon (not shown) may be expanded, thus opening the stent. Subsequently, the outer delivery sheath120is removed, leaving the opened stent in the blood vessel16.

Although this invention has been described in connection with specific forms and embodiments thereof, it will be appreciated that various modifications other than those discussed above may be resorted to without departing from the spirit or scope of the invention as defined in the appended claims. For example, functionally equivalent elements may be substituted for those specifically shown and described, certain features may be used independently of other features, and in certain cases, particular locations of elements, steps, or processes may be reversed or interposed, all without departing from the spirit or scope of the invention as defined in the appended claims.