Catheter Assembly for Blood Clots Removal

Abstract

An endovascular catheter has an elongate catheter body having a distal portion, a proximal portion, a transition portion and a central lumen extending longitudinally through the catheter body, with the distal portion having a larger central lumen than the proximal portion. A guidewire tube extends through a hole in the transition portion from the proximal end of the distal portion through the central lumen of the distal portion to the distal end of the distal portion.

Claims

1. An endovascular catheter comprising: an elongate catheter body having a distal portion, a proximal portion, a transition portion and a central lumen extending longitudinally through the catheter body, wherein the distal portion has a larger central lumen than the proximal portion, wherein the catheter body comprises an inner wall on the distal portion and an inner wall on the proximal portion, wherein the distal portion has a distal tip having a distal end and an outer wall and wherein the proximal portion has an outer wall; a hole located on the transition portion; a guidewire tube having a distal end, a proximal end and an inner lumen extending longitudinally and wherein the guidewire tube is affixed to the inner wall of the distal portion; and wherein the guidewire tube is extended through the hole in the transition portion from the proximal end of the distal portion through the central lumen of the distal portion and through the distal tip of the distal portion; and wherein the distal end of the guidewire tube is terminated outside of the distal end of distal tip of the distal portion and is the most distal part of the endovascular catheter.

2. The catheter of claim 1, wherein the proximal end of the guidewire tube is affixed to the transition portion of the catheter body.

3. The catheter of claim 1, wherein the distal end of the guidewire tube is affixed to the inner wall of the distal tip of the distal portion.

4-8. (canceled)

9. The catheter of claim 1, wherein the distal end of the catheter body is angulated and has an angle with respect to a longitudinal axis ranging between 20-90 degrees.

10. The catheter of claim 1, wherein a radiopaque marker is located on the distal tip.

11. The catheter of claim 1, wherein the distal end of the guidewire tube is spaced-apart from the distal end of the distal tip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1 illustrates an extension catheter according to one embodiment of the present invention.

[0069] FIG. 2 illustrates an extension catheter according to another embodiment of the present invention.

[0070] FIG. 3 is a cross-sectional view of a catheter assembly for removal of clots incorporating the extension catheter of FIG. 1.

[0071] FIG. 4 is an enlarged sectional view of the distal portion of a guide catheter and the extension catheter of FIG. 1.

[0072] FIG. 5A illustrates another embodiment of the extension catheter with an expandable tip.

[0073] FIG. 5B is an enlarged sectional view of the area C in FIG. 5A.

[0074] FIG. 6A illustrates the expandable tip of the tubular member of FIG. 5A in a compressed configuration inside the distal end of the guiding catheter.

[0075] FIG. 6B shows the distal end of the tubular member of FIG. 6A with the expandable tip expanded and positioned adjacent blood clots that are to be removed.

[0076] FIG. 7A is an enlarged sectional view of one embodiment of the area A/B in FIG. 4.

[0077] FIG. 7B is an enlarged sectional view of another embodiment the area A/B in FIG. 4.

[0078] FIG. 8 shows a cross section of an endovascular catheter having a hybrid reinforcement with a braid surrounding a helical coil.

[0079] FIG. 9 illustrates the outer jacket of the catheter body.

[0080] FIG. 10 shows a device for removing blood clots.

[0081] FIG. 11 shows a distal cross-sectional area of another endovascular catheter having a dual coil reinforcement with an outer coil having a distal end surrounding an inner coil having a distal end.

[0082] FIG. 12 shows a distal cross-sectional area of yet another endovascular catheter having a dual coil reinforcement with an outer coil having surrounding an inner coil and both coils have a conjoint distal end.

[0083] FIG. 13 shows an aspiration catheter with a guidewire tube positioned inside the aspiration lumen of the aspiration catheter and attached to the aspiration catheter on both ends.

[0084] FIG. 14 shows an aspiration catheter with a guidewire tube positioned within the aspiration lumen of the aspiration catheter, with the proximal end of the guidewire tube attached to the aspiration catheter and a distal end not attached to the aspiration catheter.

[0085] FIG. 15 shows the aspiration catheter of FIG. 13 with an angulated distal tip to increase blood clot removal ability.

[0086] FIGS. 16A, 16B, 16C and 16D show the distal ends of alternative embodiments of the aspiration catheters in FIGS. 13, 14 and 15.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0087] FIG. 1 illustrates an extension catheter 100 that includes a tubular portion 101 and a pushing/pulling wire 102. The tubular portion 101 has a distal end 103 and a proximal end 104. The wire 102 is attached to the proximal end 104 of the tubular portion 101 at a connection point 105. The extension catheter 100 has an outer lumen 106 and an inner lumen 107. The tubular portion 101 may also include a reinforced wall 108. One radiopaque marker 109 is located on the distal end 103 of the tubular portion 101, and another radiopaque marker 110 is located on the proximal end 104 of the tubular portion 101. The tubular portion 101 of the extension catheter 100 may be 2-100 cm long, while the attached pushing/pulling wire 102 may have any size and length suitable for interventional procedures.

[0088] The tubular portion 101 may be constructed from any suitable biocompatible plastics and elastomers used in medical devices exhibiting the following characteristics: flexibility, durability, softness, and easily conformable to the shape of the treatment and to minimize risk of harm and trauma.

[0089] The tubular portion 101 may also include an inner liner (not shown). The inner liner may be of a polymeric lubricious composition including but not limited to polytetrafluoroethylene (TFE) polymer to reduce friction. The reinforcement 108 may include but is not limited to braid, coils, laser cut tube, knit and combinations thereof. The materials of choice can be stainless steel, polymers and super-elastic alloys such as Nitinol.

[0090] The reinforcement 108 may be partially constructed of polymeric fibers or carbon fibers either replacing a portion of the metallic ribbons/wires or polymeric materials or placed in conjunction with a ribbon or wires in the braid. Other metals (e.g., noble metals such as members of the platinum group or gold) may be used in the braid itself in much the same way to impart radiopacity to the braid. To tailor the stiffness of the braid, the braid may first be wound and portions of the ribbon then removed. Also, the reinforcement 108 may be discontinuous leaving polymer alone without reinforcement.

[0091] Ribbons or wires making up the braid and coils can also contain a minor amount of other materials. Fibrous materials, both synthetic and natural, may also be used. In certain applications, particularly smaller diameter catheter sections, more malleable metals and alloys (e.g., bold, platinum, palladium, rhodium, etc.) may be used. A platinum alloy with a few percent of tungsten is sometimes preferred partially because of its radiopacity. Suitable nonmetallic ribbons or wires include materials such as those made of polyaramides (Kevlar), polyethylene terephthalate (Dacron), or carbon fibers.

[0092] The pushing/pulling wire 102 attached to the tubular portion 101 of the extension catheter 100 may have variety of configurations including but not limited to circular, oval, square, flat and combinations thereof. The wire 102 may be made with any suitable metal, preferably Nitinol, and may have a variety of tapered section(s) to provide a proper flexibility and ability to pull and push the tubular portion 101 back and forth within the body or other catheters.

[0093] FIG. 2 shows an alternative configuration for the extension catheter 200. The extension catheter 200 includes the tubular portion 201 and the pushing/pulling wire 202. The tubular portion 201 has a distal end 203 and a proximal end 204. The wire 202 is connected to the proximal end 204 of the tubular portion 201 at a connection point 205 and also is attached to the distal end 203 of the tubular portion 201 at another connection point 206. Such connection of the wire 202 to the distal end 206 and the proximal end 205 of the tubular portion 201 provides an additional internal reinforcement within the tubular portion 201, and provides better pushability of the tubular portion 201 when the extension catheter 200 is introduced into another catheter or navigated inside the body. The extension catheter 200 has an outer lumen 208 and an inner lumen 207. One radiopaque marker 209 is located on the distal end 203 of the tubular portion 201, and another radiopaque marker 210 is located on the proximal end 204 of the tubular portion 201.

[0094] The distal end 203 of the tubular portion 201 and the proximal end 204 of the tubular portion 201 may have one of the following openings, including but not limited to circular, oval, elliptical, angulated, irregular shape or combinations thereof. A largest possible aperture or enlargement of the distal end 203 of the tubular portion 201 and/or on the proximal end 204 of the tubular portion 201 will provide higher suction efficacy and better ability to remove blood clots and other tissue.

[0095] Coating of the external surface 211 of the tubular portion 201 of the extension catheter 200 may also be beneficial to reduce the friction of the extension catheter 200 but also to facilitate a seal between the tubular portion 201 of the extension catheter 200 and a guide catheter (not shown).

[0096] There are two most common coatings that may be used on the surface of the tubular portion 201 of the extension catheter 200: hydrophobic coating and hydrophilic coating. Hydrophobic coatings offer coefficients of friction in the range of approximately 0.15 to 0.3. In contrast, hydrophilic coatings are much more lubricious and have coefficients of friction in the range of 0.005 to 0.2. Hydrophilic coatings, by their nature, must be wet in order to exhibit lubricity, while low friction hydrophobic coatings do not need to be wet. In most cases, a dry hydrophobic coating is more lubricious than a dry hydrophilic coating.

[0097] A primary purpose of hydrophobic coatings such as polytetrafluoroethylene or polyxylylene is to act as a barrier against liquids. If a device must be sealed so that moisture, contrast, saline, blood do not get inside or between, one of these hydrophobic coatings will work well to prevent liquids from or on the device's surface and act as a sealant over areas where liquid can penetrate.

[0098] Hydrophilic coatings imbibe water and most of them are in fact comprised of more than 90% water when wet. However, most medical hydrophilic coatings rely on primer coats or base coats for adhesion to a surface, and these primers tend to be relatively hydrophobic, which could cause them to act as liquid barriers and serve a seal between outer surface of the tubular portion 201 of the extension catheter 200 and another device.

[0099] Given the differences in functions, applications for hydrophobic and hydrophilic coatings are different, and some applications overlap. The present invention may be one of the examples where both coatings may be advantageous.

[0100] It is important to mention that recent development of polymers that include a lubricious component(s) has seen much progress, and such polymers may include a lubricious component (s) like ProPell that significantly improves the lubricity of a medical device.

[0101] FIG. 3 shows a cross sectional view of a catheter assembly 300 for removal of clots and other tissue. The catheter assembly 300 comprises an extension catheter 301, a guide catheter 302 and a seal 303. The extension catheter 301 can be the same as the extension catheter 101 of FIG. 1, and is introduced inside the guide catheter 302 through the Touhy Borst 312. The extension catheter 301 comprises a tubular portion 304 having a distal end 305 and proximal end 306. The pushing/pulling wire 307 is attached to the distal end 305 of the tubular member 304 at the attachment area 308, and in this specific embodiment the wire 307 is attached to the proximal end 306 of the tubular member 304 at the attachment area 309. The manner in which the wire 307 is attached to the tubular member 304 improves pushability of the tubular member 304 when introduced into the guide catheter 302, and any other procedural manipulations to and at the treatment site. The distal end 305 of the tubular member 304 is positioned outside the guide catheter 302 while the proximal end 306 of the tubular member 306 is positioned inside the guide catheter 302. The guide catheter 302 comprises a soft tip 313 located on its distal end, and a Y-connector 310 has an outlet arm 311 that functions for suction attachment and the Touhy Borst 312.

[0102] The soft tip 313 provides a sealing feature, which under suction from within the guide catheter 302 when suction is applied at the suction port 311 folds around the tubular member 304 (not shown) and secures closure around the guide catheter 302, thus creating vacuum along the tubular portion 304 of the extension catheter 301 and the guide catheter 302. The seal area 303 is configured to allow a free movement of the tubular portion 304 of the extension catheter 301 within the guide catheter 302. One radiopaque marker 314 is located on the distal end 305 of the tubular portion 304 and another radiopaque marker 315 is located on the proximal end 306 of the tubular portion 304.

[0103] In the spirit of this invention, the tubular portion 304 of the extension catheter 301 is shorter than the length of the guide catheter 302. The length of the tubular member 304 may be within 2-100 cm long, preferably 15-30 cm long.

[0104] Other options to seal the space between the tubular portion 304 of the extension catheter 302 and the guide catheter 302 may include additional member(s) either provided on the outer surface of the tubular portion 304, or within the lumen of the guide catheter 302, or both. Although the seal options have been described above with respect to certain embodiments, it will be appreciated that various changes, modifications and alterations may be made to such above-described seal embodiments without departing from the spirit and scope of the present invention.

[0105] FIG. 4 shows the catheter assembly 400 with an enlarged distal view inside the blood vessel 401. The catheter assembly 400 comprises an extension catheter 402 can be the same as the extension catheter 101 of FIG. 1. The extension catheter 402 is positioned within the distal end of the guide catheter 403. The extension catheter 402 comprises a tubular member 404 and a pushing/pulling wire 405 attached to the tubular member 404 at a proximal attachment area 406 and a distal attachment area 407. A lubricious coating 408 is formed on the outer surface of the tubular member 404. Such coating facilitates movement of the tubular member 404 within the guide catheter 403 and outside of the guide catheter 403 when within the vessel 401. The guide catheter 403 has a soft tip 409 on its distal end which provides a less traumatic interface against vessels and other tissue during introduction of the guide catheter into the body. During the placement of the catheter assembly 400 at the treatment side, when there is no aspiration applied, the soft tip 409 is in an “open” position, as shown in FIG. 7A.

[0106] When aspiration is applied at the proximal end of the guide catheter 403 (at the port 311 as shown in FIG. 3), the aspiration is applied to all inner lumens of the catheter assembly 400 along the guide catheter 403 and the tubular portion 404 of the extension catheter 401, as shown by arrows 410. Aspiration from within the catheter assembly 400 affects the clot 411 surrounding the distal end of the tubular portion 404. Under aspiration from within the catheter assembly 400, the clot 411 begins entering the distal end of the tubular portion 404 of the extension catheter 402 as shown by arrows 410.

[0107] Once aspiration is applied to the proximal end of the guide catheter 403, the clot 411 starts flowing into the distal end of the tubular portion 404 as shown by the arrows 410, and creates suction flow resistance. After blood clot(s) 411/412 enters the tubular portion 404 of the extension catheter 401, vacuum pressure increases. The soft tip 409 folds around the tubular portion 404 of the extension catheter 402 and begins acting like a seal, as shown in FIG. 7B. With higher aspiration pressure within the catheter assembly 400, a better-yielded seal is produced by the soft tip 409 against or around the guide catheter 403. Also, a blood clot within the seal area (not shown) may aid in providing a better seal.

[0108] In addition, the catheter assembly 400 has a unique configuration for the inner aspiration lumens, with a larger inner lumen 413 within the guide catheter 403 than the inner lumen 414 within the tubular portion 404 of the extension catheter 402.

[0109] This unique configuration increases the flow of aspirated clots and improves the efficacy of clot removal.

[0110] FIG. 5A shows an extension catheter 500 according to another embodiment, where the extension catheter 500 comprises a tubular portion 501 and a pushing wire 502. The tubular portion 501 has an expandable tip 503 attached to the main body 504. The pushing wire 502 is attached to the main body 504 of the tubular portion 501 at an attachment area 505. The expandable tip 503 is located on the distal end of the tubular portion 501 and is attached to the tubular portion 501 at an attachment area 506. The expandable tip 503 has a funneled or conical configuration with the very distal end 507 having a larger inner and outer dimension than the proximal end of the expandable tip 503. The expandable tip 503 is shown in an expanded configuration in FIGS. 5A and 5B.

[0111] The expandable tip 503 can be made of a tubular braid 508, is coated and has its complete surface covered with silicone 509, as shown in FIG. 5B. The importance of the expandable tip 503 is the fact that the very distal end 507 has an aperture 510 that has a larger diameter than the diameter of the main body 504. Such larger aperture on the distal end 507 of the tubular member 501 significantly improves the efficacy of blood clot removal.

[0112] The space or voids within the braid 508 are filled up and covered with silicone 509, thus creating a shield that prevents penetration and suction of blood clots through the outer surface of the expandable tip 503. Therefore, it guarantees that the maximum vacuum pressure can be applied at the aperture 510.

[0113] The tubular braid 508 may be made of a plurality of wires having sizes between 0.0005-0.0030 inches and the same or different inner/outer dimensions, and constructed of wire strands made of metals, alloys, polymers, Nitinol, cobalt-chromium alloys, Platinum, Platinum-Iridium alloys, polymers or combinations thereof. The wire strands may be formed into a tubular circular shape, tubular oval shape or any suitable shapes, and may be made using (but not limited to) circular wires, oval wires, flat wires and combinations thereof.

[0114] The angle of the tubular braid 508 (i.e., angle between two crossing filaments of the braid—not shown) plays an important role of easing the expanding and collapsing braid. An easier-collapsing braid requires less force for pushing the braid through other restrictive tubes when in the collapsed configuration; for example, pushing through the guiding catheter. A small braid angle of less than 30 degrees in the collapsed configuration and less than 70 degrees in the expanded configuration will be more amenable and would create less friction during introduction and manipulations within and outside of the guide catheter.

[0115] The radial size of the overall braid 508 in the expanded configuration may have dimensions in any range between 0.5 mm-50 mm to assure proper fit into the treatment area. The braid 508 of the expandable tip may have between 8 and 144 strands, and a variety of wire configurations including, but not limited, to: one wire on one wire (1/1); one wire on two wires 1/2); two wires on two wires (2/2); two wires on one wire (2/1) and other suitable combinations.

[0116] Silicone or silicone rubbers are synthetic polymers containing silicon together with carbon, hydrogen, oxygen, and are commonly used in medical devices and implants. One of the most unique mechanical properties of silicone rubbers are excellent elongation of 1000% or more, flexibility and a durometer range of 5 to 80 Shore A. Such elongation and durometer ranges will provide the braid 508 with a shield in the expanded and collapsed configurations. It is important to mention that softer forms of silicone have the ability to retain their softness indefinitely.

[0117] The most common assembly methods for joining silicone components include insert molding and bonding. While insert molding process involves injection molding around an existing part, bonding normally entails joining silicone components with other polymers with adhesives. In the present invention, the silicone coat 509 is preferably applied on braid 508 and within the braid 508 strands by dipping. Other silicone covering methods may include but are not limited to tipping and cuffing.

[0118] FIG. 6A shows an extension catheter 600 having a tubular member 601 comprising an expandable tip 602 connected to a pushing wire 603 at a connection area 604. The extension catheter 600 is shown inside the guiding catheter 605, and the extension catheter 600 can be the same as the extension catheter 201 in FIG. 2. A soft tip 606 is located on the distal end 607 of the guiding catheter 605. The tubular member 601 is shown within the guiding catheter 605 before deployment to the treatment site. The expandable tip 602 of the tubular member 601 is in a compressed configuration and exhibits a tubular shape. Once the expandable tip 602 is pushed distally using the pusher wire 603 outside of the guiding catheter 605 and leaves the distal end 607, the expandable tip 602 will assume its expanded configuration 608 as shown in FIG. 6B.

[0119] FIG. 6B shows the extension catheter 600 as in FIG. 6A but partially outside the distal end 607 of the guiding catheter 605. The expandable tip 602 is in the expanded configuration and has an enlarged distal aperture 609. The distal aperture 609 of the expandable tip 602 is positioned at clots 610 to be removed from the vessel 611. Upon activation of aspiration at the proximal end of the guiding catheter 605 (not shown), suction of clots 610 begins inside the aperture 609 and along the extension catheter 600 and the guide catheter 605.

[0120] Once suction of the clots 610 starts, vacuum pressure shown by arrows 612 increases inside the extension catheter 600 and the guiding catheter 605. Suction activation will cause the soft tip 606 of the guiding catheter 605 to encircle the outer surface of the extension catheter 600, and create a seal.

[0121] The distal expandable tip 602 opens to a larger inner lumen 609 than its normal lumen size upon release from the guide catheter 605 when inside the guiding catheter 605. The tubular member 601 with a larger lumen 609 of the expandable tip 602 will increase the efficacy of clot removal.

[0122] The tubular member 601 of the extension catheter 600 is configured to be pushed through and out of the guide catheter 605, and retrieved back into the guide catheter 605 using the pushing wire 603, before blood clot removal, during blood clot removal, after clot removal and during removal at combinations of these times.

[0123] The expandable tip 602 having a tubular braid and coated with silicone is suitable to assume a pre-set expanded shape of any desired conical configuration when pushed outside of the guide catheter 605.

[0124] The extension catheter with an expandable tip that is made of a tubular braid and coated with silicone may be embodied in other forms and configurations without departing from the spirit of the present invention. Furthermore, the embodiments of the expandable tip illustrated in the present invention should be considered in all aspects as illustrative and not restrictive and such expandable tip may also be implemented in a conventional catheter and micro-catheter for any suitable use to treat endovascular and outside of endovascular diseases, illnesses or disorders.

[0125] Braided and coiled shafts (also known as braid and coil reinforced shafts) have been a trending topic in the world of medical catheters recently. With the growing popularity of complex minimally invasive surgeries and the rising demands of the procedural requirements, the need for shafts with tighter tolerances and improved characteristics has increased drastically. By utilizing braiding, coiling, multiple braiding, multiple coiling, or combinations of the above, for reinforcements, shafts can be provided with thinner walls while also improving the pushability, steerability, torque, and non-kinking features that non-reinforced shafts lack. With all approaches to tighten the wall of the catheters, a new challenge with catheter compression has arisen and needs to be resolved. More specifically, when the catheter is pushed percutaneously from outside the body to remote locations within the body, often times more than 100 cm from the distal end of the catheter, it often causes a very distal portion of the catheter to compress or create an “accordion” which limits the catheter aspiration and other performance abilities. To address this challenge, a new catheter wall structure is proposed.

[0126] FIG. 8 shows a cross section of an endovascular catheter 800. The catheter 800 has an elongate flexible catheter body 801 having a distal end 802, a proximal end 803, an inner central lumen 804 extending longitudinally through the catheter body 801, and a catheter wall 805. The catheter wall 805 comprises a tubular inner liner 806, a hybrid reinforcement 807 and a variable durometer outer jacket 808, positioned in this order radially from the central lumen 804 to the exterior. A radiopaque marker 809 is located at the proximity of the distal end 802, and a soft tip 810 is located at the very distal end 802 of the catheter 800.

[0127] The distal tip 810 of the catheter body 801 is configured to be relatively atraumatic when it engages with tissue (e.g., vascular walls) of the patient, yet stiff enough to allow at least the distal opening 811 to substantially maintain its cross-sectional shape, or otherwise resist geometric deformation as the distal tip is maneuvered over a guidewire or another device (e.g., another catheter). The outer jacket 808 of the catheter 800 defines an angled outer surface 813 that tapers very distally from a diameter of the outer jacket 808 to a smaller outer diameter 812 at the distal end 802 of the catheter 800. The angled outer surface 813 of the tip 810 is often referred to as a soft tip, and helps to guide the distal tip 810 of catheter body 800 along a curved vascular wall and may help reduce adverse interactions between the distal tip 810 of catheter body 800 and the vascular wall.

[0128] The radiopaque marker 809 is at least partially embedded in the outer jacket 808 and adhered to the distal end 814 of the hybrid reinforcement 807. This arrangement prevents the distal end 814 of the hybrid reinforcement from being exposed outside the outer jacket 808. The radiopaque marker 809 may be bonded, welded, fused or heat shrink to the distal end 814 of the hybrid reinforcement 807 and/or fused or heat shrunk to the inner liner 806. The hybrid reinforcement 807 may also be bonded, fused or heat shrunk to the inner liner 806. The radiopaque marker 809 may be formed from any suitable material, and may be in the form of a continuous ring, a discontinuous ring, a ring with one or more radial slits, or multiple segments that extend around the perimeter of the catheter body 801. The radiopaque marker 809 is positioned to indicate the location of the distal tip 810 of the catheter body 801 and is located at the proximity of the distal opening 811.

[0129] The inner tubular liner 806 may be formed by dip coating on a removable mandrel or may be in the form of a tubular liner made of PTFE. Optionally, a tie layer surrounding the inner layer 806 (not shown) may be added to provide a better bond when heat shrinking or bonding layers of the catheter wall 805. The tie layer may be made of polyurethane and have a wall thickness of no more than about 0.004 inches, and may extend along at least 3 cm or more from the distal end 809 of the catheter body 801.

[0130] The inner liner 806 may be comprised of two or more longitudinal segments (not shown). The first distal segment of the inner liner 806 may be made of PTFE to provide distal inner lubricity, while at least one proximally adjacent segment may be made of, but is not limited to, urethane or polyurethane elastomer or other polymers, to increase the stiffness of the proximal portion of the catheter 800. The length of the distal segment of the inner liner 806 may be 1-25 inches, and the length of the proximally adjacent segment of the inner liner 806 may have a length of 1-80 inches. Alternatively, the inner liner 806 may be terminated before the distal end of the catheter 800 to improve the flexibility of the distal end of the catheter 800. The inner liner 806 may be made of, but is not limited to, urethane, polyurethane or other similar materials. The length of the distal segment of the inner liner 806 may be between 5-50 cm, and preferably 10-20 cm.

[0131] The hybrid reinforcement 807 comprises a helical coil 815 and a braid 816 overlying each other. The helical coil 815 surrounds the inner liner 806 when viewed radially from the inner liner 806 towards the outer jacket 808. The braid 816 encircles or overlaps the helical coil 815. The helical coil 815 may be made or formed from a stainless steel or a shape memory alloy (SMA) wire, rounded or flat, with a constant or variable pitch and the desired diameters, and include a tapered configuration if needed. Also, the helical coil 815 may be made of a wire bundle that includes two, three or more wires wound together. The layout of the helical coil 815 may be adjusted to achieve the desired pitch profile (e.g., the change in pitch over the length). The SMA is an alloy that “remembers” its original shape and when deformed returns to its pre-deformed shape when heated. The SMA preferably comprises an Austenite state at body temperature.

[0132] The braid 816 may be formed from a plurality of wire strands having a dimension that is between about 0.0003 inches and about 0.010 inches, and made of one of the following materials: metals, alloys, shape memory material (e.g., Nitinol), cobalt-chromium alloys, Platinum, Platinum-Iridium alloys, polymers (e.g., Nylon, Polyester, etc.), or any combination thereof. The braid 816 may include strands of the same dimensions or of different dimensions that are braided using a circular wire, oval wire, flat wire or any other suitable wire configuration.

[0133] The configurations for the hybrid reinforcement 807 may include any desirable structure made of both its components (coil and braid). For example, the configurations for the helical coil 815 may include variable pitch, variable wire size, different outside diameter dimensions, or tapered configuration. The braid 816 may be made in any desirable configuration as listed in the paragraph above. Alternatively, the hybrid reinforcement may have the same structure along the entire length of the catheter 800 with the same helical coil configuration and the same braid.

[0134] FIG. 8 shows the hybrid reinforcement 807 comprising the helical coil 815 surrounding the inner liner 806 and the braid 816 surrounding the helical coil 815, Alternatively, the structure of the hybrid reinforcement 807 may be reversed with the braid 816 surrounding the inner liner 806 and the helical coil 815 surrounding the braid 816 (not shown)

[0135] The distal end of the coil 815 and the distal end of the braid 816 may be covered by the distal marker 809. The distal end of the coil 815 may be terminated more distally than the overlapping braid or more proximally than overlapping braid (not shown).

[0136] Alternatively, the hybrid reinforcement 807 may comprise a braid surrounding the inner layer, and a helical coil surrounding the braid (not shown). The braid may be terminated more distally than the overlapping coil or more proximally than the overlapping coil (not shown).

[0137] The structure of the catheter 800, especially the construction of the hybrid reinforcement 807, provides all needed catheter performance characteristics, such as: strength, flexibility, kink resistance, torque, shape retention, and compression resistance. The structure also provides a good integrity of the overall catheter 800 with the overall catheter 800 having a tensile strength higher than 2 lbs., as well as a true 1:1 push/pull while tracking through tortuous anatomy. It is also important to maintain a large inner diameter defined by the catheter wall thickness ratio: the inner diameter to the outer diameter of the catheter 800. It is desirable that the catheter wall thickness ratio is 0.80 or higher.

[0138] FIG. 9 illustrates the outer jacket 808 of the catheter body 801. While the outer jacket 808 may be formed of multiple segments, the catheter 800 shown in FIG. 9 is made of five discrete tubular segments, as an example. The segment 51 is the most flexible and may be made from Pebax 2533, among other possible materials. The segment 51 may also extend to a very distal end of the catheter body 801 and provide a soft tip 810 at the very distal end. The other segments 52, 53 and 54 are all preferably made from Pebax 3533, although other materials are also possible. The segment 55 is also preferably made from Pebax 6533 or 7533, although other materials are also possible. The outer jacket may be formed from at least two, and as many as twenty or more, discrete tubular segments. The difference in durometer between the tubular segments may be at least about 5 D. The durometer difference between the very proximal and the very distal tubular segments may be at least about 30 D.

[0139] The outer jacket 808 is made of polymers with several segments of a variable durometer, with a lower durometer segment usually located on the distal end and higher durometer segments located progressively proximally along the catheter length. The segments of variable flexibility may be made from, but are not limited to, the following materials: Tecoflex EG-80A; Tecoflex EG-85A; Pebax 2533, Pebax 3533, Pebax MX1205; Pebax5533, Pebax 6433; Pebax 7233, Nylon 6, Nylon 12 and any combination thereof.

[0140] For increasing the tension resistance in the distal zone of the catheter 800, a support filament may be carried between the inner liner 806 and the hybrid reinforcement 807, or within the helical coil 815 and the braid 816 (not shown). The axially extending filament may increase the tensile strength of the catheter 800 to at least three or more pounds. The filament material may include, but is not limited to, Vectren, Dacron or Kevlar fibers.

[0141] FIG. 10 shows another aspect of the present invention, where a device 1000 includes an aspiration catheter 1001 having a distal end 1002 and a proximal end 1003; and a liquid aspiration pump 1004 attached via a tube 1005 to the proximal end 1003 of the aspiration catheter 1001. The liquid aspiration pump 1004 is attached to the blood collecting bag 1006. The liquid aspiration pump 1004 functions to directly remove blood clots and other tissue from the body, unlike commonly-used air aspiration pumps that use air suction from inside the blood container to aspirate clots and other tissue. Cycling of the liquid aspiration pump 1004 may further enhance efficacy to remove clots. Higher clot recanalization rates may be achieved by cyclic aspiration at 3-10 Hz, which in experimental work has outperformed static aspiration when liquid medium is used to aspirate clots.

[0142] To secure maximum clot removal efficacy, the aspiration catheter 1001 should have the largest inner diameter and a thin wall to be compliant with the limiting inner diameters of introducer sheaths and guiding catheters that are commonly used in the most interventional procedures. However, to secure catheter performance characteristics and compatibility with introducer sheaths and guiding catheter, it is advantageous that the ratio R of the catheter inner lumen diameter ID to the catheter outer lumen diameter OD should be more than 0.80.

[0143] The liquid aspiration pump 1004 has mechanically actuated positive displacement powered by a rotating motor incorporated in the pump assembly (not shown) and may be powered by line power or battery. It is desirable to cycle the rotating motor at less than 10 Hz frequency while maintaining the motor speed below 2000 RPM to achieve the best efficacy to remove clots and other liquids. Cycling of the liquid aspiration pump 1004 will cause the pump aspiration pressure to continuously change up and down, and produce a pulsating effect on blood clots to be removed. Such blood clot pulsation will disrupt or break the structure of blood clots and prevent the aspiration catheter 1001 from clogging. The logic behind this approach is that cycling pressure/forces will induce fatigue on the blood clots or other tissue to be removed, thereby enabling the removal of more entrenched blood clots and prevent catheter clogging.

[0144] FIG. 11 shows a distal cross-sectional area of another endovascular catheter 1100. The catheter 1100 has a variable flexibility outer jacket 1101 having a distal end 1102, an inner central lumen 1103 extending longitudinally through the catheter 1100, and a catheter wall 1104. The catheter wall 1104 includes a tubular inner liner 1105, a dual coil reinforcement 1106, a radiopaque marker 1107 and the variable flexibility outer jacket 1101 positioned in this order, radially from the central lumen 1103 to the exterior. The radiopaque marker 1107 is located at the proximity of the distal end 1102, and a soft tip 1108 is located at the very distal end 1102 of the catheter 1100. The soft tip 1108 may be an integral part of the variable flexibility outer jacket 1101.

[0145] The dual coil reinforcement 1106 has an inner coil 1109 and an outer coil 1110 overlying each other when viewed radially from the inner liner 1105 towards the outer jacket 1101. The inner coil 1109 and the outer coil 1110 may be made or formed from a stainless steel or a shape memory alloy (SMA) wire, can be rounded or flat, with a constant or variable pitch and the desired diameters, and include a tapered configuration if needed. Also, the coils 1109 and 1110 may be wound together by using multiple wires to form a combined helical coil. The layout of the helical coils may be adjusted to achieve the desired pitch profile (e.g., the change in pitch over the length). The SMA is an alloy that “remembers” its original shape and when deformed returns to its pre-deformed shape when heated. The SMA preferably comprises an Austenite state at body temperature.

[0146] The inner coil 1109 has a distal end 1111, and the outer coil 1110 has a distal end 1112. The distal end 1111 of the inner coil 1109 and the distal end 1112 of the outer coil 1110 may be covered by the distal radiopaque marker 1107. The distal end 1111 of the inner coil 1109 and the distal end 1112 of the outer coil 1110 may be terminated flush under the radiopaque marker 1107 and between the distal and proximal ends of the radiopaque marker 1107. Alternatively, the distal end 1111 of the inner coil 1109 may be terminated more distally than the distal end 1112 of the outer coil 1110 under the radiopaque marker 1107 and between the distal and proximal ends of the radiopaque marker (not shown). Also, the distal end 1111 of the inner coil 1109 may be terminated more proximally than the distal end 1112 of the outer coil 1110 under the radiopaque marker 1107 and between the distal and proximal ends of the radiopaque marker (not shown).

[0147] The radiopaque marker 1107 may be bonded to the dual coil reinforcement and/or to the inner liner 1105 using any conventional methods, including but not limited to glueing, heat shrinking, and squeezing (not shown).

[0148] For increasing the tension resistance in the distal zone of the catheter 1100, at least one support filament may be carried between the inner liner 1105 and the inner coil 1109 (not shown), between the inner coil 1109 and the outer coil 1110 (not shown) or between the outer coil 1110 and the outer jacket 1101. The axially extending filament may be placed in all these locations if needed. The filament material may include, but is not limited to, Vectren, Dacron or Kevlar fibers.

[0149] It is known in the art that for catheter reinforcement structures that include dual coils, the inner coil and the outer coil may have only one common distal end. Such a dual-coil reinforcement configuration may be fabricated by winding a wire in the first direction starting from the proximal end to the distal end to create the inner coil, and then using the same wire to continue winding back from the distal end to the proximal end to create the outer coil. In such a pattern, the very distal end of both coils will be conjoined.

[0150] FIG. 12 shows a distal cross section of another endovascular catheter 1200. The catheter 1200 has a variable flexibility outer body 1201, a distal end 1202, an inner central lumen 1203 extending longitudinally through the catheter 1200 and a catheter wall 1204. The catheter wall 1204 includes a tubular inner liner 1205, a dual coil reinforcement 1206 and a variable flexibility outer jacket 1201 positioned in this order, radially from the central lumen 1203 to the exterior. A radiopaque marker 1207 is located at the proximity of the distal end 1202, and a soft tip 1208 is located at the very distal end 1202 of the catheter 1200.

[0151] The dual coil reinforcement 1206 has an inner coil 1209 and an outer coil 1210 overlying each other when viewed radially from the inner liner 1205 towards the outer jacket 1201. The inner coil 1209 and the outer coil 1210 have a conjoined or distal end 1211. The distal end 1211 is located under the radiopaque marker 1207 and between the distal and proximal ends of the radiopaque marker 1207.

[0152] The flexible outer jackets 1101 and 1201 may be similar to that which is shown in FIG. 9.

[0153] FIG. 13 shows an endovascular catheter 1300 comprising an elongate catheter body having a distal portion 1301, a proximal portion 1302, and a transition portion 1303 between the distal portion 1301 and the proximal portion 1302. A first central lumen 1304 extends through the distal portion 1301, and a second central lumen 1305 extends through the proximal portion 1302. The two lumens 1304 and 1305 communicate longitudinally with each other and can also be considered as one lumen having varying dimensions. The distal portion 1301 has a larger cross-sectional dimension than the proximal portion 1302. The central lumen 1304 located within the distal portion 1301 has an inner wall 1306. The central lumen 1305 located within the proximal portion 1302 has an inner wall 1307. The distal portion 1301 of the catheter 1300 has a circular distal opening 1308. A distal tip 1309 is located adjacent the distal circular opening 1308 of the distal portion 1301. The distal tip 1309 may be made of a softer polymer than the remainder of the distal portion 1301 to make the distal tip 1309 atraumatic when navigating endovascular areas. A radiopaque marker 1310 is provided on the distal end of the distal portion 1301 in proximity to the distal opening 1308. A hole 1311 is located within the transition portion 1303. The hole 1311 can be made by drilling, cutting, or puncturing the transition portion 1303, or other techniques known in art.

[0154] A guidewire tube 1312 which provides for guidewire placement has a distal end 1313, a proximal end 1314 and an inner lumen 1315 extending longitudinally therethrough. The guidewire tube 1312 may be made of any suitable polymer, and also may comprise of any reinforcement components known in art. The guidewire tube 1312 is positioned inside the inner lumen 1306 of the distal portion 1301 of the catheter 1300. The proximal end 1314 of the guidewire tube 1312 extends through the hole 1311. The distal end 1313 of the guidewire tube 1312 is extended beyond the plane of the distal opening 1308. The proximal end 1314 of the guidewire tube 1312 is affixed to the catheter 1300 around the hole 1311 at the location 1316 using glue or any other methods for attaching polymers, including but not limited to, fusing, stretching, expanding, or shrinking. The guidewire tube 1312 may also be affixed to the inner wall 1306 of the distal portion 1301 at location 1318 which is at the distal circular opening 1308. In addition, the guidewire tube 1312 may be affixed to the inner wall 1306 at location 1317, or at any location along the inner wall 1306 of the distal portion 1301. Attachment of the guidewire tube 1312 to the inner wall 1306 at the distal portion 1301 of the catheter 1300 may be accomplished using any suitable attachment methods known in the art.

[0155] A guidewire 1319 is shown for reference and is extended through the lumen 1315 of the guidewire tube 1312. It is desirable that the combined outside dimension C of the proximal portion 1302 and outside dimension D of the guidewire 1319 be similar to the distal outside dimension B of the distal portion 1301 of the catheter 1300. Having C+D to be about the same as B allows for the inner lumen of a medical device such as a guiding catheter or sheath to be able to accommodate, the entire endovascular catheter 1300 (including the guidewire 1319.

[0156] The distal portion 1301 and the proximal portion 1302 of the catheter 1300 can be made as one continuous piece using techniques that are well-known in art, such as a tapered extrusion or lamination over the tapered mandrel. The distal portion 1301 and the proximal portion 1302 of the catheter 1300 may also be made of two separate tubes and then affixed together. The catheter body 1300 and the guidewire tube 1312 may be made of any polymer, with or without reinforcement.

[0157] FIG. 14 shows a catheter 1400 which is the same as the catheter 1300 in FIG. 13 (so the same numerals are used in both FIGS. 13 and 14 to designate the same elements) with the exception that the guidewire tube 1312 is not attached to the inner wall 1306 of the distal portion 1301, but is only attached to the transition portion 1303 at location 1316. As a result, the distal end 1313 of the guidewire tube 1312 is positioned in a free orientation in that it is not fixed with respect to the distal tip 1309 of the catheter 1300.

[0158] FIG. 15 shows a catheter 1500 which is the same as the catheter 1300 in FIG. 13 (so the same numerals are used in both FIGS. 13 and 15 to designate the same elements) with the exception that the very distal end 1501 of the catheter 1500 is angulated. Such angulation of the distal end 1501 creates an oval-shaped aperture 1502 that provides a larger cross-sectional area compared to a circular distal opening, such as the circular distal opening 1308 shown in FIG. 13 and FIG. 14. The larger cross-sectional area provided by such an oval-shaped opening increases the clot aspiration forces of the catheter 1500 and its ability to remove blood clots. The angulated distal end 1501 of the catheter 1500 has an angle A (with respect to a longitudinal axis) which may be between 10 degrees to 80 degrees, and preferably between 30 to 60 degrees. The degree of angulation A may vary depending on the clinical application.

[0159] FIG. 16A shows the distal tip 1309 of the catheter 1300 as shown in FIG. 13 except that the distal end 1313 of the guidewire lumen 1312 is terminated flush with the circular distal opening 1308 of the catheter 1300.

[0160] FIG. 16B shows the distal tip 1309 of the catheter 1400 as shown in FIG. 14 except that the distal end 1313 of the guidewire lumen 1312 is terminated flush with the circular distal opening 1308 of the catheter 1300.

[0161] FIG. 16C shows the distal tip 1309 of the catheter 1500 as shown in FIG. 15 except that the distal end 1313 of the guidewire lumen 1312 is terminated flush with the very distal end of the oval opening 1308.

[0162] FIG. 16D shows the distal tip 1309 of the catheter 1300 as shown in FIG. 13 except that the distal end 1313 of the guidewire lumen 1312 is terminated inside the circular distal opening 1308 of the catheter 1300. Such an option of terminating the distal end 1313 of the guidewire tube 1312 within the catheter's distal opening can also be implemented in the catheter 1400 of FIG. 14 (not shown) and in the catheter 1500 of FIG. 15 (not shown).

[0163] While the location of the distal end 1313 of the guidewire tube 1312 within the catheter's distal end as shown in FIGS. 13S 14, 15, 16A, 16B, 16C, 16D varies, it will have a minor impact on the catheter's ability to remove clot. However, these alternatives provide different options to the interventionalist to suit their personal preference.

[0164] Each catheter 1300, 1400 and 1500 has a separate guidewire tube 1312 located inside the enlarged central lumen 1304 of the distal portion 1301. This arrangement provides a larger cross-sectional area of the central lumen 1304 of the distal portion 1301 that is dedicated for aspiration compared to prior aspiration catheters. The overall outside dimension of the catheters shown in FIGS. 13, 14 and 15 (including the guidewire 1319) needs to fit into an introduction or location placement catheter, such as a guiding catheter or sheath. Practically, there is no room to increase the outside dimensions of the catheters shown in FIGS. 13, 14 and 15. By providing a separate guidewire tube 1312 located inside the central lumen 1304 of a distal portion 1301 that functions as an aspiration portion, the catheters 1300, 1400 and 1500 provide a larger cross-sectional area of the central lumen 1304 at the distal tip 1309 that can be used for improving aspiration by guaranteeing stronger aspiration power, while maintaining other required catheter characteristics for access, safety, and durability. This is contrasted with the central lumen 1305 of the proximal portion 1302, which can have a smaller cross-sectional area to allow for the guidewire 1319 to run longitudinally outside the proximal portion 1302. Thus, the configuration of the catheters 1300, 1400 and 1500 provide an overall outside dimension (including the guidewire 1319) that allows the entire assembly (i.e., the catheter 1300, 1400 or 1500, plus the guidewire 1319) to be accommodated within a guiding catheter or sheath.

[0165] Although this invention has been described with reference to preferred embodiments and examples, those having ordinary skill in this art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention as found in the claims which follow.