Abstract:
Apparatus for delivering fluids to blood vessels, body cavities and the like, includes a resilient tubular wire for threading lengthwise into the lumen of a catheter and out the distal end thereof to a target location of a body passageway to be treated. The tubular wire has a central lumen and a distal end formed into a coil, which, when straightened, may be threaded lengthwise through the catheter, but when extended out the distal end of the catheter at the target location, resumes its coiled shape. The tubular wire includes openings at least on the outside of the coils for discharging radially outwardly medication carried in the lumen of the wire. In this manner, the medication may be directed toward the wall of the passageway to infuse a diseased area being treated.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to invasive medical devices for delivering medications and therapeutic agents into blood vessels, body cavities, organs, tumors and the like. More particularly, the present invention relates to devices for concentrating the delivery of such medications and agents to the walls of the blood vessels and cavities. 
     2. State of the Art 
     Various vascular diseases involving vessel walls, for example, arterial sclerosis, aneurysm or other weakening of the vessel wall, occlusive lesions, etc., may benefit from the application of medications to the affected area of the vessel wall. This may be done systemically by injecting medication into the vessel and then allowing the blood to carry the medication to the affected area. The problem with this approach is that high dosages of medication are required to ensure that some small portion reaches the affected area, and the high dosage may be harmful to other organs or body parts. This approach is also expensive and not especially effective. Another approach to treating diseases of vessel walls is to place a block before and after the affected area and then inject medications into that portion of the vessel between the two blocks. The problem with this approach is that blood flow is stopped for a certain amount of time and this, in itself, is dangerous; also, it generally cannot be stopped long enough for effective uptake of the medication by the vessel walls. 
     Another prior art approach is to thread a catheter through the blood vessel to the affected area and then either supply the medication through the catheter to the affected area or supply the medication through a needle which itself is threaded through the catheter, pierce the vessel wall with the needle, and then supply the medication (see U.S. Pat. No. 5,354,279). 
     An additional prior art approach to supplying medication to a vessel wall involves the use of an inflatable sleeve positioned adjacent the affected area, where the sleeve includes an annular cavity holding the medication. When the sleeve is inflated to expand outwardly, the medication held in the cavity is placed into contact with the vessel walls and released thereinto. The problem with this approach is that the blood vessel again is blocked for a time and thus a gradual therapeutic regimen is not possible. Other approaches to delivering medication to vessel walls are disclosed in U.S. Pat. Nos. 5,681,281, 5,364,356, and 5,112,305. 
     It would therefore be desirable to have a device for delivering medication, therapeutic agents, and the like efficiently and effectively to a blood vessel wall, body cavity wall, etc. which is non-occlusive and substantially non-inhibiting of blood flow. It would also be desirable to have such a device which delivers medication substantially directly to a vessel wall, and may do so for an extended period of time. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a device for delivering medication, therapeutic agents, and the like efficiently and effectively to a blood vessel wall, body cavity wall, etc. 
     It is also an object of the invention to provide such a device which is non-occlusive and substantially non-inhibiting of blood flow. 
     It is another object of the invention to provide such a device which may be easily deployed through the vascular system and other body cavities to desired target locations for delivering the medication, therapeutic agents, and the like. 
     It is also an object of the invention to provide such a device which is capable of delivering medication substantially directly to a vessel or cavity wall. 
     It is still another object of the invention to provide such a device, in accordance with one aspect thereof, in which the degree to which blood or other cavity fluid mixes with the medication during administration may be controlled. 
     The above and other objects are realized in one illustrative embodiment of the invention which includes a resilient tubular wire for threading into a blood vessel or other body passageway to a target wall location which is to be treated with medication or other therapeutic agent. The tubular wire forms a coil at its distal end, and is configured for straightening and threading lengthwise into, through and out the terminal end of a catheter to the target wall location. The wire resumes the coil shape within the blood vessel or body cavity when its distal end exits the terminal end of the catheter. The wire includes a plurality of cuts or openings at least on the outside of the coils for discharging radially outwardly medication carried in the hollow of the wire. Discharge would occur once the coil was in place at the target location by supplying medication through the proximal end of the tubular wire. An occlusive coating formed, for example, by dip coating could be disposed over the wire and openings and then cuts selectively made in the coating to further control discharge of the medication. 
     In accordance with one aspect of the invention, rather than use a tubular wire, a solid wire could be used, again, having a coil shape at its distal end. A plurality of vesicles would be formed on the outside of the coils for holding fluid or dissolvable solids to be delivered toward the vessel or cavity walls. A sheath or membrane may be disposed over the coil wire to cover the vesicles. Such a membrane may be dissolvable in blood or body cavity fluid to release the contents of the vesicles or the membrane may be made of a permeable material through which the medication could pass. 
     In accordance with another aspect of the invention, the spacing between adjacent coils may be selectively varied to either increase the mixing of blood or body cavity fluid with the medication (adjacent coils separated some distance), or decrease the mixing (little or no distance between adjacent coils). 
     In accordance with yet another aspect of the invention, the coiled portion of the tubular wire may be coated with a soft coating of foam, fuzz, or hydrogel to provide a better seal between adjacent wires in the coil and between the coil and the wall of the body passageway. This coating further reduces mixing of the medication and bodily fluids within the passageway. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the invention will become apparent from a consideration of the following detailed description presented in connection with the accompanying drawings in which: 
     FIG. 1 is a side, partially cross-sectional view of a tubular wire fluid delivery device made in accordance with the principles of the present invention; 
     FIG. 2 is a side, partially cross-sectional view of the device of the present invention shown in place in a blood vessel within a stented vessel or duct; 
     FIG. 3 is a side, partially cross-sectional view of an hourglass coil configuration of the present invention in which adjacent coils are in contact with one another; 
     FIG. 4 is a side, partially cross-sectional view of an hourglass coil configuration of the present invention in which adjacent coils are spaced apart; 
     FIG. 5 is a side, cross-sectional view of a solid-wire embodiment of the present invention; and 
     FIG. 6 is a side, partially cross-sectional view of a portion of the fluid delivery device of the present invention in which the outer surface of the wire is coated with a thin layer of fuzz, foam, or hydrogel. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, there is shown a side, cross-sectional view the walls of a blood vessel  4  into which has been deployed the coil portion  8   a  of a tubular wire  8  having a central lumen  10 . A non-coil portion  8   b  of the wire  8  is shown threaded in a catheter  12  which, itself, is shown threaded into the blood vessel  4 . The tubular wire shown in FIG.  1  and subsequent figures is round in cross section. However, it will be apparent that tubular wires of other cross sectional shapes may also be used, and because of their different shape and structural properties may provide distinct advantages in certain circumstances. For example, the cross section of the tubular wire  8  may be round, square, hexagonal, octagonal, rectangular, oval, eliptical, or any other desired shape. 
     The coil portion  8   a  is initially straightened and inserted lengthwise into the catheter  12  for delivery to the target location in the blood vessel  4 , but once the coil portion emerges from the distal end of the catheter, it resumes its coil shape. The threading of catheters into blood vessels and other body cavities, and the threading of wires or other treatment objects through catheters are well known to those skilled in the art. 
     The coil portion  8   a  of the tubular wire  8  is formed with a plurality of cuts or openings  16  on the outside of the coils so that at least when the portion  8   a  is unconstrained to resume the coil shape, the cuts  16  open additionally to allow flow of fluid medications, therapeutic agents, etc from the central lumen  10 . Cuts  16  may also be provided on the inside of the coils as well, to help determine the shape and flexibility of the wire  8 . (see enlarged section of wire at  18 ). However, it will be apparent that these inside cuts will preferably not communicate with the central lumen  10  of the wire  8  because any openings on the inside of the coils will tend to provide medication toward the inside of the coil, which is not desired. Otherwise, some or all of the inward cuts should preferably be sealed with an occlusive coating to prevent inward flow of the medication. 
     The cuts or openings  16 , whether on the inside or outside of the coil, may be formed non-uniform in size, shape, or spacing so as to vary the flexibility and stiffness of the wire  8 . It will be apparent to those skilled in the art that the shape, size, and spacing of cuts formed on an elongate member will have a direct effect on the ultimate shape, flexibility, and stiffness of the member. For example, widely spaced openings  16  will make the wire  8  less flexible than more closely spaced openings. Similarly, deeper or wider openings  16  will make the wire  8  more flexible. Thus, where a tighter coil is desired, the cuts may be placed closer together, or made deeper or wider, and where it is desired that the coil have a larger diameter, the cuts or openings may be made shallower or at a greater spacing. 
     It will also be apparent that the geometry of the cuts on the inside of the coil, if any, will preferably vary from that of the cuts or openings on the outside of the coil. As noted above, the cuts on the inside of the coil preferably are not as deep as the cuts on the outside of the coil, and do not communicate with the lumen  10  of the tubular wire. Thus, the spacing, size, and shape, of the cuts or openings may be non-uniform between the outside and inside of the coil, as well as varying along the length of the tubular wire. 
     Since cuts or openings  16  which communicate with the lumen  10  of the tubular wire are formed on the outside of the coils, when medication is transmitted through the lumen  10  of the tubular wire  8  and out the openings  16 , the medication is caused to flow radially outwardly toward the walls of the blood vessel  4 . In this manner, medication can be delivered directly toward a diseased portion of the wall of the blood vessel  4  to better infuse the diseased portion with the medication. Of course, if the coil portion  8   a  has been dimensioned to press outwardly against the walls of the blood vessel  4 , any medication emerging from the openings  16  would come in direct contact with the wall. 
     Preferably, the tubular wire  8  is made of nickel-titanium alloy, but may also be made of various polymers, stainless steel, composites, or other suitable materials and combinations of these. The cuts or openings  16  are preferably made by saw cutting or grinding (see co-pending U.S. patent application, Ser. No. 08/714,555, filed Sep. 16, 1996, now issued as U.S. Pat. No. 6,014,919, such as with an abrasive blade, but may also be formed by chemical etching, laser cutting, electro-discharge machining (EDM) or other method suitable for making micro cuts or openings. The preferred saw cutting method uses a micromachining process which allows very accurate longitudinal, depth, width, and angular position control of the cuts on the very fine tubular wire. This method has been found to be superior to other methods in controlling the quality and consistency of cuts, and is also far more economical than other methods, such as EDM. 
     In use, the catheter  12  is threaded through the blood vessel  4  until the distal end of the catheter reaches a target location in the blood vessel to be treated. Then, the tubular wire  8  is threaded through the lumen of the catheter  12  and out the distal end thereof to enable the coil portion  8   a  to resume the coil shape. The medication may be supplied through the lumen  10  of the tubular wire  8  to exit the cuts or openings  16  and thereby treat the diseased portion of the blood vessel  4 . 
     After delivery of the medication, the tubular wire  8  may then be retracted back through the catheter  12 . Alternatively, the tubular wire  8  could include a discontinuity  20  which, when mechanically stressed, would cause severance at the location of the discontinuity. By this means, the substantially linear proximal portion of the tubular wire  8  may be advantageously detached from the distal coiled portion  8   a  so as to leave it in place in the blood vessel  4  to act as a stent to maintain the blood vessel patency (see co-pending U.S. patent application, Ser. No. 09/023,806, filed Feb. 13, 1998), now issued as U.S. Pat. No. 6,022,369. The entire disclosure of U.S. Pat. No. 6,022,369 is hereby incorporated by reference. 
     A polyurethane or similar plastic coating  21  (shown in the enlarged view  18  of FIG. 1) may be applied to selected parts of the coil portion  8   a  to better control the outflow of medication through the openings  16 . For example, if only one side of the vessel wall were to be treated, a polyurethane coating could be applied to all but those portions of the coils which were to be in contact or adjacent to the side of the blood vessel wall to be treated. The coating  21  will block the exit of medication from the openings  16  which are covered, while allowing the exit of medication through openings that are not covered. Alternatively, the entire coil portion  8   a  could be covered with a plastic coating (for example, by dip coating), and then cuts made selectively in the coating, to allow discharge of medication from the tubular wire  8  only from selected locations along the tubular wire. 
     Another approach to controlling release of medication through the openings  16  in the tubular wire  8  would be to include in the lumen  10  of the tubular wire  8  an inner liner  22  (shown in the enlarged view  18  of FIG. 1) which itself has very small perforations (or porosity) selectively positioned along its length to control the medication discharge, for example, to provide more uniform distribution of medication discharge along the coil portion  8   a . The liner material might illustratively be polysulfone. 
     FIG. 2 shows a side, partially cross-sectional view of a blood vessel  24  in which is disposed a conventional stent  26  for holding the blood vessel or duct open. Shown disposed within the conventional stent  26  is the coil portion of a tubular wire  28  through which medication is to be delivered to the walls of the blood vessel  24 . Note that the coils of the coil portion of the tubular wire  28  are in intimate contact with one another so that medication released toward the walls of the blood vessel  24  cannot be greatly diluted by blood flowing through the coil interior of the tubular wire. Rather, the tight coil configuration of the tubular wire  28  tends to hold the medication between the exterior of the coil and the vessel walls to better medicate the target locations of the blood vessel being treated. The presence of the regular stent  26  may also inhibit the flow of blood adjacent to the blood vessel walls and this further inhibits dilution of the medication. 
     FIG. 3 is a side, partially cross-sectional view of a blood vessel  34  in which is disposed the coil portion of a tubular wire  38 , with the coil portion having an hourglass shape as shown. The coils located at the ends of the coil portion have a greater diameter and are in contact with the walls of the blood vessel  34  while the coils located centrally are smaller in diameter and are out of contact with the walls, to define an annular space  40  between the coils of the tubular wire  38  and the walls of the blood vessel. The medication is released into this annular space  40  to contact the walls of the blood vessel  34 , with little interference from blood flowing in the blood vessel. In particular, the combination of adjacent coils of the tubular wire  38  being in contact with one another and the end most coils of the coil portion contacting the walls of the blood vessel  34 , work to stagnate fluid located in the annular space  40  so that medication released into the space is not washed away. 
     FIG. 4 shows a similar hourglass configuration of the coil portion of a tubular wire  48  (as in FIG.  3 ), but here the adjacent coils are spaced apart so that the annular space  50  is less isolated and protected from the flow of blood in the blood vessel  44 . In this configuration, of course, more blood would mix with the medication and dilute it. By controlling the spacing between adjacent coils of the coil portion of the tubular wire  48 , the amount of mixing of the released medication and blood can be controlled. 
     FIG. 5 shows an alternative embodiment, in cross-sectional view, of a solid wire  54  delivery device, shown disposed against a vessel or cavity wall  58 . Formed on the side of the wire  54  adjacent the wall  58  are a plurality of vesicles or cavities  62  in which fluid medication, pellets, capsules, or similar medicaments are disposed. By positioning the wire  54  tightly against the wall  58 , the medication in the vesicle  62  migrates therefrom to the vessel wall. 
     Advantageously, a membrane or sheath  64  is disposed about the wire  54  (formed, for example, by dip coating) to hold the medication in place in the vesicles  62  until the wire is deployed to the desired target location. The sheath  64  may be made of a blood dissolvable material such as polyvinyl alcohol or a permeable material such as polysulfone, to allow the discharge of the medication from the vesicles either upon dissolution of the sheath or through the sheath, as the case may be. 
     Shown in FIG. 6 is yet another alternative embodiment of the fluid delivery device of the present invention. FIG. 6 provides a side, partially cross-sectional view of a portion of the coil section  8   a  of the tubular wire  8  disposed against the inner surface of a blood vessel wall  4 . In this embodiment, the wire  8  having lumen  10  is advantageously coated on its outside with a thin coating  70  of fuzz, foam, or hydrogel to help prevent mixing of blood or other bodily fluids with the therapeutic fluid being delivered. This layer  70  of soft fuzz, foam, or hydrogel provides an improved seal between adjacent coils, and between the coils and the vessel wall  4 . With this embodiment, the therapeutic fluid may be more completely isolated from the surrounding bodily fluids, and prevented from mixing therewith, thus improving the efficacy of treatment and reducing the required dosage. It will be apparent that this coating  70  may be included with several of the previous embodiments of the invention as described above. 
     It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention and the appended claims are intended to cover such modifications and arrangements.