An infusion catheter includes a catheter body having a proximal end, a distal end, and two or more lumens extending therethrough. The infusion catheter also includes an infusion tube having a proximal end, a distal end, and one or more ports disposed therethrough. The first lumen of the catheter body is in fluid communication with the lumen of the infusion tube. A central member has a distal end connected to the distal end of the infusion tube, a proximal end, and a proximal portion slidably received in the second lumen of the catheter body. The infusion tube is disposed relative to the central member such that axial advancement of the central member relative to the catheter body radially collapses the infusion tube over the central member and axial retraction of the central member relative to the catheter body radially expands the infusion tube about the central member.

BACKGROUND

1. Technical Field

The present disclosure relates generally to medical devices and methods. More particularly, the present disclosure relates to an infusion catheter and methods for its use in delivering substances to vasculature.

2. Description of the Related Art

Catheters are used for delivering drugs through vasculature and other body lumens for a wide variety of purposes. It is often desirable to deliver thrombolytic and other substances to the peripheral vasculature, in particular the peripheral venous vasculature, in order to lyse and help remove clots in patients suffering from deep vein thrombosis (DVT) and other conditions. A number of catheters have been proposed for this purpose. For example, the catheter illustrated in U.S. Pat. No. 5,554,114 includes a pre-shaped spiral coil at its distal end, where the coil can be reduced to a smaller diameter by axially advancing a core wire to facilitate introduction into the vasculature. Although the benefits of such a pre-shaped coil are clearly evident, since the maximum diameter of the coil is fixed, the coil may be too small to treat relatively large blood vessels and may have difficulty in adequately conforming to and delivering thrombolytic and other agents throughout the length of the vessel to be treated especially in vessels of varying diameters. Thus, it would be desirable to provide alternative and improved catheters and methods for delivering thrombolytic agents to the venous and other vasculature.

SUMMARY

An infusion catheter useful for delivering drugs to the peripheral venous and other vasculature comprises a catheter body, an infusion tube, and a central member. The catheter body has a proximal end, a distal end, and at least a first lumen and a second lumen therethrough. The infusion tube has a proximal end, a distal end, and at least one lumen therethrough, where the proximal end of the infusion tube is connected to the distal end of the catheter body. The infusion tube and catheter body are connected and aligned so that the first lumen of the catheter body is in fluid communication with the lumen of the infusion tube so that substances delivered through the first lumen of the catheter body will flow into and through the lumen of the infusion tube. The infusion tube, in turn, is adapted to deliver liquid agents through its wall, typically having a plurality of perfusion ports formed therethrough. Alternatively, the infusion tube could be porous, perforate, slitted, slotted, or otherwise provided with flow passages adapted to release therapeutic, diagnostic, and other substances through its wall into the blood vessel or other body lumen being treated.

The central member has a distal end and a proximal end, where the distal end of the central member is connected to the distal end of the infusion tube. The proximal portion of the central member is slidably received in the second lumen of the catheter body. In this way, the central member may be axially advanced and retracted in order to lengthen and foreshorten the infusion tube, respectively. The infusion tube may be wrapped around the central member one or more times so that, when the central member is axially extended, the infusion tube will be closely positioned about the outer surface of the central member to facilitate insertion of the infusion catheter into a body lumen. Conversely, when the central member is axially retracted in the proximal direction, the infusion tube will expand radially outwardly. Advantageously, it has been found that the infusion tube will assume a generally helical or spiral configuration against the inner wall of the blood vessel or other body lumen in which it has been radially expanded. The helical or spiral configuration helps distribute the drug being delivered to the luminal wall being treated more uniformly in the radial direction.

In embodiments of the present disclosure, the infusion tube has a generally straight or linear shape or configuration. That is, when left in neither tension nor compression, the infusion tube will assume a generally straight configuration. In embodiments, a straight stiffening wire is provided within the lumen of the infusion tube in order to provide column strength. Usually, the infusion tube will have a polymeric body with a certain degree of stiffness, such as a nylon polymer having a stiffness or hardness in the range from about 50 kpsi to about 800 kpsi. Providing the stiffening wire increases the column strength of the infusion tube. The real advantage, however, is that when the infusion tube is foreshortened, the stiffening wire helps provide a greater hoop strength as the infusion tube assumes its spiral or helical configuration about the central member. Typically, the stiffening wire is a stainless steel wire having a diameter in the range from about 0.08 mm to about 0.7 mm. The stiffening wire is attached at its distal end to the infusion tube at or near the distal end of the infusion tube. The stiffening wire extends through the entire length of the infusion tube and into the first lumen within the catheter body. Still more usually, a proximal end of the stiffening wire will not be attached to the catheter body, i.e. it will be free so that it can move distally and proximally as the catheter body and infusion wire are bent when advanced through the vasculature or other body lumen.

In embodiments for the treatment of the peripheral vasculature, the infusion tube typically has a length in the range from about 1 cm to about 100 cm, and a width, typically an outer diameter, in the range from about 0.3 mm to about 2.8 mm. The catheter body, in turn, has a length in the range from about 5 cm to about 150 cm, and a width, typically an outer diameter, in the range from about 0.66 mm to about 4 mm, and the central member has a length in the range from about 10 cm to about 175 cm, and a width, typically a diameter, in the range from about 0.4 mm to about 3.7 mm. In still other embodiments, the infusion tube will have ports for releasing the substance, and the ports will be formed along its length. The ports may be spaced apart by distances in the range from about 2.5 mm to about 50 mm and may have width or diameter dimensions in the range from about 0.01 mm to about 0.25 mm. In still further specific embodiments, the ports may have variable spacing or porosity along the length of the infusion tube, in order to provide or improve uniform distribution.

Thrombolytic and other substances may be delivered to body lumens, particularly the peripheral venous vasculature, using the catheter as described above. For example, the central member may be advanced to draw the infusion tube to a target location within the body lumen, typically a location which is at least partially occluded with thrombus. After being positioned within the treatment region, the central member is drawn proximally to foreshorten the infusion tube and radially deploy the infusion tube outwardly so that it expands toward a wall portion of the body lumen in a helical or spiral geometry, including the regions of thrombus which may be formed along the wall surface. The thrombolytic or other substance may then be introduced into the lumen of the infusion tube so that the substance infuses outwardly through the ports or other release structures toward the wall of the body lumen, typically infusing into the thrombus in order to help break up and dissolve the thrombus or other occlusive materials.

As described above in connection with the apparatus of the present disclosure, the infusion tube will generally have a straight configuration, i.e. will have a certain elasticity which assumes a straight configuration when neither tension nor compression are being applied. The infusion tube may be helically wrapped, coiled or spiraled around the central member to provide for a more compact profile when the central member is in an advanced position. Alternatively, the infusion tube may be substantially axially aligned with the central member when the central member is in an advanced position. The infusion tube of the present disclosure is capable of conforming to regions of widely varying diameter within the body lumen to assure good contact and/or efficient delivery of the thrombolytic and other substances into the lumen. The structure of the present disclosure is also particularly useful for treating very long regions within a body lumen, typically regions extending from about 1 cm to about 100 cm within a peripheral vein.

DETAILED DESCRIPTION

Embodiments of the presently disclosed catheter assembly will now be described in detail with reference to the drawings wherein like reference numerals identify similar or identical elements in each of the several views. In the discussion that follows, the term “proximal” or “trailing” will refer to the portion of a structure that is closer to a user, while the term “distal” or “leading” will refer to the portion of the structure that is farther from the user. In addition, the term spiral as used in association with the infusion tube and the central member means that the infusion tube extends along and at least partially around the central member in a helical, coiled or like configuration.

Referring initially toFIGS. 1-4, a catheter assembly10constructed in accordance with the principles of the present disclosure includes a handle housing50, a movable handle28, a catheter body12, a central member14, and an infusion tube16. Catheter body12extends at least partially into a distal end54of handle housing50and includes a hub18at its proximal end that operates to reinforce the coupling of catheter body12into the distal end54of handle housing50. Hub18may be, for example, flexible shrink wrap tubing encapsulating at least a portion of the distal end54of handle housing50and at least a portion of a proximal end of catheter body12. Handle housing50includes a first connector20at or near its distal end54for attaching to a fluid source such as a source of a thrombolytic agent to be delivered through the catheter body12and a second connector21at or near its distal end54for attaching to saline or other liquid for flushing the catheter body12.

As shown in the cross section ofFIG. 2, the catheter body12defines a first lumen22that receives the thrombolytic or other agent through the port20and delivers it to a proximal end24of the infusion tube16. The proximal end24of infusion tube16may be shrink wrapped (not explicitly shown) and heated to bond the proximal end24of infusion tube16to first lumen22of catheter body12at a mid-joint60(FIG. 1) via shrink wrap tubing (not explicitly shown). Catheter body12includes a second lumen26which slidably receives the central member14which is typically a polymeric tube or the like operably coupled to the handle28at its proximal end. Using the handle28, a physician can axially advance (seeFIG. 5) and proximally retract (seeFIG. 7) the central member14in order to control deployment of the infusion tube16, as will be described in more detail with reference toFIGS. 3,5, and7.

The infusion tube16is straight in its “free” configuration, i.e. where no tension or compression is being applied to the infusion tube16. In certain embodiments, the polymeric material (e.g., nylon-12) from which the infusion tube16is made may possess sufficient stiffness and elasticity without reinforcement to perform as described herein. Alternatively, as illustrated inFIG. 4, a stiffening member or wire35that extends through at least a portion of the lumen of the infusion tube16may be provided to provide added rigidity to infusion tube16. In this scenario, a distal end of the stiffening member or wire35is attached at or near its distal end to the distal end of the infusion tube16and attached at its proximal end to the catheter body12within the infusion lumen22, as best seen inFIG. 2. In other embodiments, however, a proximal end of the stiffening wire35is unattached at its proximal end so that the proximal portion of the stiffening wire may move freely within the lumen22of the catheter body as the catheter itself is advanced through a body lumen.

As best seen inFIGS. 1 and 3, a one-way valve36(e.g., a duckbill valve) may be provided at or near the distal end34of the central member14in order to prevent back-bleed, i.e., blood flow into central member14. One-way valve36may be, for example, shrink wrapped or heat-sealed to central member14to reduce the cross-sectional profile of catheter assembly10and enable catheter assembly10to be introduced into a blood vessel or other body lumen. One way valve36also facilitates the introduction of a guide wire38(seeFIG. 3A) or a medical fluid into vasculature via central member14.

The infusion tube16defines a lumen17(seeFIG. 3) along its length and further includes a plurality of release ports30which serve to release fluid from the lumen17into a blood vessel BV or other luminal wall.

Relative to infusion tube16, the material from which the central member14is made is more rigid or stiff. For example, central member14may be made from a polymer such as a polyimide or polyetheretherketone (“PEEK”). A distal end32of the infusion tube16is attached near distal end34of the central member14so that axial advancement of the central member14operates to lengthen or elongate the infusion tube16, as shown inFIG. 1, in order to reduce the cross-sectional profile of the infusion tube16to enable the infusion tube16to be introduced into a blood vessel or other body lumen.

Conversely, proximal retraction of the central member14, as shown inFIG. 3, radially expands the infusion tube16so that it moves outwardly toward the inner wall W of the blood vessel BV or other body lumen. The infusion tube16may be spirally or helically wrapped around the central member14in its deployment configuration, as shown inFIGS. 1 and 3A.

As shown inFIGS. 1,3and3B, one or more radio-opaque markers or bands19may be disposed on the catheter body, central member, and/or infusion tube16and/or16ato allow for clear visualization of the treatment region using fluoroscopic imaging. In addition, to promote visualization of the treatment region, the infusion tube16may be comprised of a radiopaque filler such as barium sulfate, for example.

Referring now toFIGS. 5-8, central member14extends proximally from catheter body12at least partially within handle housing50and is operably coupled to a distal end42of movable handle28. Distal end42of movable handle28is configured to axially reciprocate within proximal end52of handle housing50to control movement of central member14. More specifically and as shown inFIG. 5, as movable handle28is axially advanced, as depicted by directional arrow “A”, tension in central member14is substantially reduced or eliminated such that infusion tube16is lengthened or elongated, as shown inFIG. 1. As best shown in the cross-section ofFIG. 8, distal end42of movable handle28includes an annular bushing45having an outer surface for sliding engagement with an inner surface of handle housing50. Annular bushing45operates to coaxially stabilize movable handle28centrally within handle housing50during axial retraction and advancement of handle28. In addition, annular busing45acts as a seal to allow pressurized flushing of the annular space between central member14and catheter body12through second connector21.

As shown inFIG. 7, as movable handle28is axially retracted within handle housing50, as depicted by directional arrow “B”, infusion tube16is compressed by central member14such that infusion tube16shortens and radially expands toward the inner wall W of the blood vessel BV or other body lumen.

As best shown in the cross-section ofFIG. 6, movable handle28includes a pair of longitudinal recesses48a,48bdisposed at least partially along opposing sides of the distal end42of movable handle28. A pair of pins46a,46bare disposed through opposing sides of handle housing50. Pins46aand46bare configured to be received within longitudinal recesses48a,48b, respectively, of a movable handle28. A plurality of indents44are incrementally formed within longitudinal recesses48asuch that upon axial translation of handle28, pin,46bis configured to be brought into and out of registration with indents44. Indents44may be axially spaced apart in a substantially uniform manner such that proximal retraction and/or axial advancement of movable handle28may be incrementally controlled to provide controlled radial expansion and contraction of infusion tube16within a blood vessel or other body lumen. In this way, infusion tube16may be manipulated in a controlled manner to conform to blood vessels or body lumens of various sizes. In one embodiment, pin46bis configured to receive a spring-loaded ball or detent46cwhich allows for distinct engagement with indents44. Alternatively, other known flexible or resilient engagement devices may be provided to releasably retain movable handle28at fixed positions in relation to handle housing50.

One or both of pins46a,46bmay be, for example, a dowel pin, a threaded fastener, a spring plunger, or the like, and may be adjusted (i.e., advanced into handle housing50or retracted from handle housing50) as needed. In this manner, the size (e.g., circumference) of the housing and/or handle utilized may be varied without compromising interaction between pins46a,46band longitudinal recesses48a,48b.

As can be seen inFIGS. 5 and 6, longitudinal recesses48a,48binclude a pair of distal travel limiting stops49a,49b, respectively. In use, movable handle28may be advanced until pins46a,46bengage distal travel limiting stops49a,49b, respectively. Similarly, as can be seen inFIG. 7, longitudinal recesses48a,48binclude a pair of proximal travel limiting stops49c(only one is illustrated) which engage pins46a,46bto limit or prevent further axial retraction of movable handle28.

As movable handle28is moved proximally, as illustrated by directional arrow “B” inFIG. 7, the central member14is retracted to cause the infusion tube16to radially expand into a generally spiral configuration, as shown inFIGS. 3 and 3B. Since the infusion tube16is not pre-shaped, however, the spiral will only form as the infusion tube engages the wall surface W of blood vessel BV, thus allowing the infusion tube to conform to a variety of different diameters and irregularities within and along the surface of the wall surface W of blood vessel. Thus, it would not necessarily be expected that the infusion tube16will actually achieve the uniform spiral as illustrated inFIG. 3, instead, it will more often achieve a generally helical or spiral shape which can adapt to match the topography of the wall being engaged.

As shown inFIG. 3B, catheter10, in certain embodiments, may include a second infusion tube16ain addition to infusion tube16. In this scenario, infusion tube16aoperates substantially as described above with respect to infusion tube16. Infusion tube16amay be spirally wrapped around the central member14to interweave with infusion tube16in the deployed state (not explicitly shown) and to radially expand with infusion tube16into a generally spiral configuration upon retraction of movable handle28(FIG. 1), as shown inFIG. 3B.

After deployment as shown inFIGS. 3 and 3B, the thrombolytic or other agent may be released into the first connector20so that it flows through lumen22(FIG. 2) and into the infusion tube16and/or16afor release into the blood vessel BV or other body lumen. Saline may be delivered through second connector21prior to any procedure to flush lumen26.

As shown inFIGS. 1,5, and7, the proximal end40of movable handle28includes a female luer39that provides access to a lumen29(FIG. 5) defined through movable handle28. Lumen29communicates with the lumen defined by central member14. A male-type cap43may be removably fastened (e.g., via threading, snap-fit, slide-fit, etc.) into female luer39to prevent access or seal the proximal end of lumen29. Upon removal of cap43, a fluid source may be removably coupled to female luer39to introduce fluid such as saline into movable handle28and central member14. Further, a guide wire38(seeFIG. 3A) may be inserted through lumen29, and into central member14, and through one-way valve36to facilitate introduction of infusion lumen16(and/or16a) and central member14into the blood vessel BV or other body lumen.

Although the specific features of the disclosure are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the disclosure.

It will be understood that various modifications may be made to the embodiments of the presently disclosed delivery catheters. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure.