MULTI-CANNULA CATHETER FOR ADMINISTERING THERAPY TO DISPARATE POINTS IN A VESSEL IN WHICH FLUID FLOW PAST THE CATHETER IS PRECLUDED

Abstract: A multi-cannula catheter assembly for administering different fluids to disparate sites within a body lumen (fig. 1). One aspect of the invention includes an inner catheter that is slidably disposed in at least a portion of an outer catheter so that a distal port on the inner catheter can be positioned at one treatment site within a body lumen and a distal port on the outer catheter positioned at a different site (fig. 1). In addition, a skirt can be deposed on either or both the inner (100) and outer catheter, proximate their distal ends. The skirt (100), for which several different embodiments are disclosed (figs. 4-7, 9-16), is furled after the distal port on the catheter to which the skirt is attached is advanced to a desired site.

Description: MULTI-CANNULA CATHETER FOR ADMINISTERING THERAPY TO DISPARATE POINTS IN A VESSEL IN WHICH FLUID FLOW PAST THE CATHETER IS PRECLUDED Field of the Invention The present invention generally relates to a multi-cannula catheter, and more specifically, to an assembly having a catheter with a distal end that is movable relative to the distal end of another catheter. Background of the Invention A conventional catheter is a flexible tube having one or more lumens extending longitudinally therethrough. The distal end of a catheter is typically inserted into a body lumen, such as a blood vessel, and advanced to a site where a medical treatment is to be administered that often involves the infusion of medicinal fluids, withdrawal of bodily fluids, or the monitoring of pressure via the lumens formed in the catheter. Catheters are also frequently used to support a medical device, such as an angioplasty balloon or a sensor for monitoring pO 2 or pCO 2 . The lumens in a catheter may serve as passages through which electronic leads extend to such a sensor, or can be used for conveying a fluid that inflates a balloon. In addition, fluid can be administered to a specific treatment site within a patient's body through a lumen in a catheter. Certain kinds of diseases of the vascular system are best treated locally rather than systemically. A systemically administered medication can have undesired effects on a patient, particularly if administered in sufficient concentration to be therapeutically effective at the diseased site in a vessel. Once administered systemically, a medication spreads throughout the patient's body and becomes diluted in the blood stream; however, a substance can also become too concentrated in an organ such as the kidney. Clearly, the benefit of a medication will be optimized and its adverse effects minimized if the medication is administered at the site where the therapeutic benefit of the medication is needed most. A conventional catheter is capable of administering a medication to a diseased site in a blood vessel or other body lumen. However, in a blood vessel, the medication is generally not retained at the site where it is administered via the catheter. Instead, once the medication is infused through a lumen in a catheter at the site within the vascular system, the blood flowing through the vessel will cause the medication to be dispersed into other parts of the patient's body. When a vessel has been diseased for some time, it is often the case that concomitant damage will occur in other parts of the body in which blood flowing through the vessel circulates. In such cases, it may be desirable to simultaneously administer different medications to treat both the diseased vessel and the damage to another portion of the patient's body caused by the diseased vessel. Currently, there is no catheter system available that can be advanced through a vessel, particularly a vein, and provide different medicinal fluids to disparate sites within the vessel. As noted above, it would also be desirable to retain the medication delivered to a site through a catheter at the site until the medication can have its beneficial effect. While a balloon disposed adjacent a distal end of a catheter is sometimes used to block blood flow past the catheter during administration of a medication or during some other procedure, the balloon must be inflated with an external source of fluid that is conveyed through one of the lumens of the catheter. In some applications, it will be preferable to minimize the diameter of the catheter, avoid unnecessary dilation of the vessel, and avoid damage to the endothelium of the vessel. Accordingly, an alternative mechanism for blocking blood flow through a vessel around a catheter would be very useful - both on a catheter that enables medicinal fluids to be infused at disparate sites within a body lumen, and on other types of catheters. It would also be desirable to allow the simultaneous delivery of medicinal fluids without mixing these fluids to avoid causing potential reactions (crystallization, for example) in the catheter. Summary of the Invention In accord with the present invention, a catheter assembly is defined that is usable for administering a first liquid to a first site in a body lumen of a patient and a second liquid to a second site in the body lumen, where the second site is substantially spaced apart from the first site. The catheter assembly includes a first tube that is flexible and elongate, having a guide lumen extending at least along part of its length. The first tube has a proximal port adapted to introduce the first liquid into a lumen, and a distal port coupled in fluid communication with the lumen and thus adapted to supply the first liquid to the first site. A second tube that is flexible and elongate has a lumen extending therethrough it, and the lumen couples a proximal port in fluid communication with a distal port on the second tube. The second tube is smaller in cross-sectional size than the guide lumen of the first tube. This configuration enables a position of the distal port of the second tube to be adjusted in the body lumen relative to a position of the distal port of the first tube, by sliding the second tube through the guide lumen to adjust its position relative to the first tube. The first liquid can be administered to the first site through the lumen and the distal port of the first tube, and the second liquid can be administered to the second site through the lumen and the distal port of the second tube. In one embodiment, the distal port of the first tube is disposed in a wall of the first tube. In a different embodiment, the guide tube comprises the lumen through which the first liquid is administered. In this embodiment, the distal port of the first tube comprises a gap defined between the outer surface of the second tube and an inner surface of the guide lumen of the first tube. A seal on the proximal end of the first tube preferably includes an adjustable compression fitting that is engaged to lock the second tube at a desired position in the guide lumen of the first tube. In some forms of the invention, the second tube includes at least one additional lumen extending longitudinally through it. Similarly, in some forms of the invention, the first tube includes at least one additional lumen extending longitudinally through it. In one embodiment, the assembly includes a skirt having a distal end and a proximal end. The proximal end of the skirt is attached in sealing relationship around an outer surface of the first tube, adjacent to its distal end, while the distal end of the skirt is adapted to seal against an internal surface of a body lumen in which the catheter apparatus is inserted, thereby preventing bodily fluid from flowing past the distal end of the first tube in a direction toward the proximal end of the first tube. In several embodiments, the skirt includes a biasing element that acts on the skirt, forcing at least a portion of the skirt radially outward into sealing relationship with the inner surface of the body lumen when the skirt is enabled to unfurl. In one embodiment of the skirt, the biasing element comprises a helical coil spring disposed radially within an interior of the skirt. Another embodiment includes a biasing element that comprises a super elastic alloy having a radially expanded memory shape. In still another embodiment, the skirt is wrapped around the catheter and deploys into a lily-like shape. In yet another embodiment, a plurality of struts extend distally from a distal edge of the skirt and are connected to the outer surface of the catheter to prevent the skirt from prolapsing. Still another embodiment employs a skirt having a generally spherical shape that remains collapsed until released and enabled to expand outwardly into contact with the inner surface of the body lumen. It may be preferable to include a sleeve that encompasses the skirt, keeping the skirt furled about the outer surface of either the first or the second tube while the catheter assembly is being advanced through a body lumen. The sleeve may extend proximally of the patient's body or alternatively, a line can be connected to the sleeve and extend outside the body lumen to enable the sleeve to be pulled from the skirt so that the skirt can unfurl to obstruct the flow of the bodily fluid through the body lumen. The sleeve can be withdrawn from the skirt after the distal port of the first tube or second tube is disposed proximate the corresponding first site or second site. It will be apparent that the skirt can also be used on a catheter assembly that does not include a plurality of cannulas. In another aspect of the present invention, a method for administering first and second fluids respectively to disparate first and second sites within a body lumen is defined. The method includes steps generally corresponding to the functions of the elements discussed above. Brief Description of the Drawing Figures The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: FIGURE 1 is a side view of portions of a catheter assembly including an inner catheter and an outer catheter, in accord with the present invention; FIGURE 2 is an enlarged side view of a portion of the catheter assembly shown in FIGURE 1, at a distal end of the outer catheter; FIGURE 3 is a cross-sectional view of the catheter assembly taken along section line 3-3 in FIGURE 2; FIGURE 3' is an alternative cross-sectional view of the catheter assembly taken along section line 3-3 in FIGURE 2; FIGURE 4 is a side view of portions of an embodiment of a catheter (e.g., the inner catheter) showing a skirt that is unfurled to block blood flow past the catheter in a vessel; FIGURE 5 is a side view of portions of another embodiment of a skirt on a catheter; FIGURE 6 is an enlarged cross-sectional view of a portion of the catheter and the skirt shown in FIGURE 5; FIGURE 7 is an enlarged side view of a different embodiment of the skirt on a portion of a catheter; FIGURE 8 is an enlarged view of the distal end of the embodiment of the skirt and catheter shown in FIGURE 7; FIGURE 9 is an enlarged side view of yet another embodiment of the skirt on a portion of a catheter; FIGURE 10 is an enlarged side view of still another embodiment of the skirt on a portion of a catheter; FIGURE 11 is an enlarged side view of an embodiment of a skirt that includes a helical spring biasing coil and a portion of a catheter; FIGURES 12A and 12B are respectively an enlarged side view and an end view of a portion of a catheter and an embodiment of a skirt that is lily shaped and extends around the catheter; FIGURE 13 is an enlarged view of a portion of a catheter and a generally spherical shaped embodiment of a skirt; FIGURE 14 is a cross-sectional longitudinal view of a blood vessel showing a catheter assembly having an inner and outer catheter being advanced through the blood vessel; FIGURE 15 is a cross-sectional longitudinal view of the blood vessel of FIGURE 14, showing a skirt around the inner catheter unfurled to block blood flow through the blood vessel; and FIGURE 16 is a side view of portions of an alternative embodiment of a multi-cannula catheter assembly, in accord with the present invention. Description of the Preferred Embodiment With reference to FIGURES 1 through 3 and 3', a multi-cannula catheter assembly 20 is illustrated. Multi-cannula catheter assembly 20 includes an inner catheter 22 and an outer catheter 24. While the embodiment of the present invention shown in these Figures depicts inner catheter 22 extending concentrically along the longitudinal axis of outer catheter 24, it will be appreciated that a guide lumen within outer catheter 24 for use in guiding inner catheter 22 may be offset to one side of the longitudinal axis of outer catheter 24, as would likely be the case if the outer catheter includes a plurality of lumens. While not shown in these Figures, it will be apparent that outer catheter 24 can include additional lumens besides the guide lumen through which the inner catheter is slidably disposed. Suitable materials for fabricating these and other catheters discussed below include PEBAX™, high-density polyethylene (HDPE), NYLON™, urethane, and polyvinyl chloride (PVC) plastics. Outer catheter 24 includes an external portion 26 having a side tube 28 that is connected in fluid communication with the guide lumen in this embodiment. If additional lumens are provided in outer catheter 24, corresponding additional side tubes similar to side tube 28 would typically be included, generally one for each of the lumens provided in the catheter that convey a fluid, or through which a lead or some other element is threaded. Side tube 28 includes a female Luer fitting 30 adapting the side tube to connect to a tube set having a corresponding male Luer fitting (not shown). Fluid can either be introduced or withdrawn from the guide lumen (or other lumens provided with similar side tubes) via the side tube that is connected in fluid communication with that lumen. For example, a medicinal fluid can be supplied to a treatment site from an external source of the fluid that is coupled to side tube 28. The fluid is introduced into and conveyed through the lumen to the distal port disposed at the treatment site. A seal 32 is compressively engaged around inner catheter 22, forming a fluid-tight seal that prevents fluid introduced through side tube 28 from leaking past inner catheter 22 where it extends through the seal. Similarly, the proximal portion of inner catheter 22 includes at least one side tube 48, which is provided with a female Luer fitting 50 for engaging a tube having a corresponding male Luer fitting. It will be apparent that fluids can be both withdrawn and administered to a patient via side tube 48 through the lumen of inner catheter 22 and that additional lumens coupled in fluid communication with corresponding additional side tubes can be included. A seal 52 is adapted to compressively engage a guide wire (not shown in FIGURE 1). The guide wire, which is initially inserted into a body lumen and advanced through the body lumen at least to a site where the distal end of the inner catheter will be disposed, is threaded through at least one lumen of the inner catheter and serves to guide the catheter assembly to this site within the body lumen. In most cases, the body lumen will be a blood vessel in a patient's body. Seal 52 prevents fluid in this lumen from leaking proximally past the guide wire. A portion 34 of outer catheter 24, which is adapted to be inserted within a body lumen of a patient, includes a port 36 formed near a distal end 38. Also disposed proximate distal end 38 of the outer catheter is a band 40, which may be visualized using a variety of imaging modalities to assist in monitoring the position of the distal end of the outer catheter relative to a site to which fluid is to be delivered through the outer catheter. Similarly, a distal end 42 of the inner catheter also includes band 40, adjacent a distal port 44 for at least the lumen through which the guide wire is initially threaded. In the enlarged view of the distal end of outer catheter 24, shown in FIGURES 3, and 3', it will be apparent that a gap 60 is formed between the distal portion of the inner catheter and the internal surface of the outer catheter at its distal end 38. Fluid flowing through the guide lumen can thus pass through gap 60. Thus, as indicated by the dash line in FIGURE 2, distal port 36, which is formed in the side wall of the outer catheter, is optional. Also shown in FIGURE 3 is a guide wire 54 disposed within a central lumen 56 at the distal portion of inner catheter 22. In FIGURE 3', an embodiment is shown in which a lumen 56' and a lumen 56" are formed within inner catheter 22 in side-by-side relationship. A guide wire 54' extends through lumen 56' in this embodiment. Gap 60 is again provided to enable fluid passing through the guide lumen of outer catheter 24 to be infused into the body lumen at the distal end of the outer catheter (as an alternative to being infused through distal port 36). It will be apparent that inner catheter 22 can be slidably adjusted within the outer catheter so that the distal end of the inner catheter and its distal port 44 are spaced apart from distal end 38 of outer catheter 24 by a desired extent. The spacing between the distal ends (or distal ports) of the inner and outer catheters is adjustable to enable different fluids to be separately administered to different treatment sites within a body lumen through multi-cannula catheter assembly 20. To adjust the spacing between the distal ports on the inner and outer catheters, one of the catheters is moved relative to the other catheter either before or after the multi-cannula catheter assembly is inserted within the body lumen of a patient's body. If the adjustment is made after insertion of the catheter assembly into the body lumen, the whole assembly will typically be advanced along the guide wire until the distal port of the inner catheter is at its desired site within the body lumen, and then the outer catheter will be drawn back over the inner catheter until the distal port (or distal end) of the outer catheter is disposed at its desired site in the body lumen. Use of bands 40 enable the disposition of the distal ports or ends of the inner and outer catheter to be determined within the patient's body with imaging modalities so that they can be positioned within the body lumen at the desired sites. Each of the catheters may be used to deliver specific drugs, blood, gene therapies, or therapeutic agents to the treatment site where the distal port of each of the respective catheters is ultimately disposed within the patient's body. Further, although only two catheters are disclosed in the drawings, it will be apparent that a third or more catheters can be added and similarly threaded through either a lumen of a concentrically outer catheter, or through a different lumen in outer catheter 24, to treat additional sites within the body lumen at different spaced-apart locations. The disposition of the sites will depend upon the anatomical variations and differences in the disease locations from patient to patient, and the adjustable nature of the multi-cannula catheter assembly permits the fluids to be administered to the appropriate sites. FIGURE 16 illustrates an alternative embodiment of a multi-cannula catheter assembly 150 that includes catheters 152 and 154. In this embodiment, the same components are provided at the proximal ends of the two catheters that remain outside the patient's body as in the embodiment first discussed above. However, in this embodiment a distal end 156 of catheter 152 extends through a relatively short distal portion 158 of catheter 154 in which the guide lumen is disposed. In addition, catheter 154 includes a much longer section 160 through which a lumen (not specifically shown) extends, in fluid communication with side tube 28. Fluid administered through side tube 28 and flowing through this lumen exits from a distal port 162 of distal portion 158. Included proximal to the distal end of catheter 152 is a skirt 90, the purpose and details of which are discussed below. Fluid administered through side tube 48 of catheter 152 flows through a lumen in the catheter (not separately shown) and exits the lumen through distal port 44, at the distal end of the catheter. Catheter 152 is freely slidable through the guide lumen within distal portion 158 of catheter 154, so that the distal ends and distal ports of each catheter may be spaced apart within a body lumen to deliver different fluids to correspondingly spaced-apart sites through the distal ports of the two catheters. The relatively short guide lumen in distal portion 158 serves the dual function of providing a path for the coaxial delivery of catheter 152 and of serving as a sleeve for keeping skirt 90 furled until the skirt is advanced from within the guide lumen sufficiently to enable the skirt to unfurl. If a skirt is provided on distal portion 158, another sleeve would likely be provided to keep that skirt furled until catheter 154 is disposed at a desired position to administer fluid into the body lumen. Because of the relatively short length of distal portion 158, catheter 152 can be shorter and still enable catheter 154 to be positioned where desired. It will be apparent that additional catheters can be included in multi-cannula catheter assembly 150, by providing an additional guide lumen on the distal portion of catheter 154 for each added catheter, or by providing multiple catheters like catheter 154, each having a distal portion 158 threaded over catheter 152 and disposed at a different position along it. Obstructive Skirt for Preventing Fluid Flow Past a Catheter FIGURES 4 and 9 illustrate an embodiment of a skirt 100 used for preventing or substantially reducing fluid flow past inner catheter 22. While each of the following embodiments of such a skirt are illustrated disposed proximate the distal end of inner catheter 22, it will be understood that each embodiment of the skirt can be included on outer catheter 24, or on distal portion 158 of catheter 154, or on a single catheter that is not part of a multi-cannula catheter system. Although the different embodiments of the skirt illustrated and discussed below have substantially different physical configurations, they are each generically referred to herein and in the claims that follow as a "skirt," since the function and purpose of these embodiments are substantially identical regardless of the configuration of the embodiment. Each skirt has two states, referred to herein as "furled" and "unfurled," respectively. When a skirt is furled, it has a relatively smaller radial extent, being fitted relatively compactly about the outer surface of the catheter to which it is attached. In contrast, when a skirt is unfurled, the radial extent of the skirt is substantially greater than when furled, enabling a distal end of the skirt or some other portion of the skirt to come into contact with an inner surface of the body lumen in which the catheter has been inserted. The function or purpose of the skirt, when unfurled, is to at least partially block the flow of a bodily fluid through the body lumen in which the catheter and skirt are disposed. By threading the catheter through the body lumen while the skirt is furled, it is possible to more readily advance the portion of the catheter on which the skirt is attached through the body lumen without causing any damage to the inner surface of the body lumen or to the skirt. The most common body lumen in which a catheter is used is a blood vessel, although it should be emphasized that the catheter can be used in other types of body lumens that are not blood vessels. Accordingly, when a catheter with a skirt in accord with the present invention is advanced through a blood vessel with the skirt furled, it may be preferable to interrupt the flow of blood through the vessel by applying a standard pressure cuff to a limb of the patient in which the blood vessel extends, as is well known to those of ordinary skill in the medical arts. The pressure cuff applies pressure to the blood vessel, preventing the blood from flowing in a direction opposite that to which the catheter and skirt is advanced through the vessel with the skirt in its furled state. In addition, application of the pressure cuff causes venous valves, if present, to relax in an open position, facilitating easy passage of the catheter through a vein and minimizing risk of trauma to venous valves. Once the catheter has been advanced to a desired position, i.e., with the distal port of the catheter disposed at a site within the body lumen, the skirt is selectively unfurled. When used in a blood vessel, after the skirt is unfurled, the pressure cuff is released to allow blood to again flow within the blood vessel, but flow of the blood past the unfurled skirt is prevented or minimized, since the skirt effectively obstructs (or at least partially obstructs) the blood vessel, preventing most of the blood from flowing past the position on the catheter at which the skirt is disposed. The skirt is normally disposed behind the distal port on the catheter to which the skirt is attached. Therefore, it will be apparent that administration of a medicinal fluid or other liquid into the body lumen through the distal port while the skirt is unfurled will prevent blood or other bodily fluids from washing the fluid away from the site to which it has thus been administered. By increasing the residency time of a therapeutic agent or other medicinal fluid administered through the distal port, the effectiveness of the agent or medicinal fluid at that site can be greatly enhanced, in contrast with the case in which the blood is flowing past the catheter without any obstruction. The diluting effect of a bodily fluid such as blood is minimized by obstructing the flow of the bodily fluid past the catheter. In addition, a therapeutic agent of other medicinal fluid infused under pressure in the retrograde direction through the catheter into the body lumen reaches body tissue that is otherwise not accessible. Also, the microvasculature of diseased tissue has greater permeability characteristics to take up and perfuse a therapeutic agent or medicinal fluid that is delivered in the retrograde direction through the body lumen. The unfurled skirt ensures that the therapeutic agent or medicinal fluid is infused through the body lumen in the retrograde direction, which may be important in treating diseased and/or ischemic tissue. Further details of skirt 100 are illustrated in FIGURE 9. In this particular embodiment, skirt 100 is fabricated from a relatively thin-walled polymer material that is "welded," adhesively bonded, shrink affixed, or otherwise mounted over distal portion 42 of the catheter. Suitable materials for use in fabricating this and other thin-walled skirts described below include polyethylene terephthalate (PET), fluoropolymer, NYLON™, urethane, or PVC plastics. Skirt 100 is formed to have a generally conical shape when unfurled, as shown in FIGURE 9. To provide a biasing force that causes skirt 100 to change from its furled state to its unfurled state, a plurality of thin metal rods or bars 104 are bonded to the inner surface of skirt 100. The metal rods or bars are made of stainless steel, corrosion resistant spring steel, or super-elastic metal, such as Nitinol, or alternatively, may be formed of an elastomeric polymer. These rods or bars create a spring biasing force directed radially outward so as to cause skirt 100 to assume a generally conical shape. The relatively wider diameter or radius of skirt 100 at its distal end brings it into contact with an internal surface of the body lumen in which the catheter is inserted. Flow of bodily fluids such as blood past skirt 100 is prevented by the unfurled state of skirt 100 blocking fluid flow through the body lumen, as will be evident from an exemplary application of a skirt discussed below. Other embodiments of a skirt having a generally conical shape are illustrated in FIGURES 5-8. In FIGURES 5 and 6, a skirt 74 having a conical portion 76 that extends radially outward from the surface of the catheter on which it is mounted is illustrated. In this case, the polymeric material from which the skirt is fabricated has an inherent elastomeric bias that provides a radially outward directed forced tending to cause the skirt to change from its furled to unfurled state so that the distal end of conical portion 76 contacts the inner surface of the body lumen. To minimize the risk of skirt 74 suffering a prolapse or inversion, a plurality of tethers 80 extend distally of skirt 74 and are bonded to the outer surface of the catheter. Alternatively, as shown in FIGURES 7 and 8, a skirt 90 having a conical portion 92 may be formed to include integral tethers 94 that are coupled distally to the outer surface of the catheter and define relatively large openings 96 between adjacent tethers 94 as shown in FIGURES 7 and 8. Skirt 90 is also shown in FIGURE 16. With reference to FIGURE 11, yet another skirt 120 is illustrated having a conical portion 122 that is expanded radially outward by a helical internal coil spring 124 when allowed to unfurl. The helical internal coil spring extends between different sections of distal portion 42 of the catheter and can be fabricated from stainless steel or spring steel, Nitinol, or a suitable elastomeric polymer. Fluid can readily exit the distal portion of the catheter through the coils of helical spring 124. When skirt 120 is furled, the coils of helical spring 124 assume a smaller diameter configuration with skirt 120 furled around the outer surface of the helical spring and catheter. Another embodiment of a skirt 110 also has a conical section 112 when unfurled. However, instead of using a spring force to bias the skirt into its unfurled state, it comprises a Malecot type structure that is selectively urged to its unfurled state by a user pulling a proximal end of a line 118 that is coupled to relatively stiff struts 114 and extends beyond the proximal end of the catheter. Struts 114 extend from the distal edge of conical-shaped portion 112 and into slots 116 that are spaced apart around a lumen of the catheter through which line 118 extends. The line may be fabricated from adhesively-bonded fibers of polyethylene, or other suitable thin, high-tensile strength material such as KEVLAR™, polycarbonate, polyether sulfone, polyetheretherketone (PEEK), or aligned PET. When line 1 18 is pulled proximally, struts 114 are forced radially outward, thereby unfurling conical portion 112 of skirt 110 into contact with the inner surface of the body lumen in which the catheter has been inserted. It should be noted that this particular construction for skirt 110 will apply a small dilating force onto the inner surface of the body lumen or blood vessel, depending upon the amount of tension exerted on line 118. Fluid can flow through slots 116 into the body lumen from the internal lumen through which line 118 extends. It should be noted that the embodiment of skirt 1 10 shown in FIGURE 10 is useful in the multi-cannula catheter assembly only upon the inner catheter, or the innermost catheter of an assembly having more than two catheters. FIGURES 12 and 13 illustrate two further embodiments for the skirt. In FIGURE 12, a skirt 130 generally has a shape like a lily when unfurled. The thin polymer material from which the skirt is fabricated includes a supporting rib 132 formed of a metallic wire or appropriate polymer plastic extending around its outer edge. When unfurled, skirt 130 tries to assume the shape shown in FIGURE 12 and thereby readily adapts to the interior cross-sectional dimension of a body lumen such as a blood vessel, sealing against the interior surface of the body lumen to partially obstruct flow of fluid therethrough. This skirt embodiment tends not to dilate the body lumen in which it is used, since any outward force delivered by rib 132 will not be directed radially, in a concentric direction. In FIGURE 13, a skirt 140 is illustrated in its "unfurled" state, a dash line 142 indicating the furled radial extent of skirt 140. Skirt 140 can be fabricated from silicone or other elastic materials that can be deployed without the influence of any surrounding fluid pressure. This embodiment tends to cause minimal dilation of the body lumen with which it is in contact, due to its relatively moderate radially directed elastic force. Referring back to FIGURE 6, an advantage of employing conical-shaped skirt 74 will be evident. If one or more distal ports 82 are provided in the wall of the catheter in the portion of the catheter encompassed by conical portion 76 (or by corresponding conical portions of the other embodiments discussed above), it will be apparent that fluid exiting through distal ports 82 will impinge directly on the inner surface of the conical portion of the skirt and not on the inner surface of the body lumen. Thus, possibility of damage due to the force of the fluid impinging upon the inner surface of the body lumen is substantially reduced. Turning again to FIGURE 16 in which multi-cannula catheter assembly 150 is shown, it will be noted that skirt 90 is included on the distal portion of catheter 152. When catheter 152 is initially inserted into a body lumen, such as a blood vessel, skirt 90 will be furled within distal portion 158 of catheter 154. Once distal port 44 of catheter 150 has been advanced to a desired site within the body lumen, catheter 154 will be drawn back relative to catheter 152, enabling skirt 90 to unfurl, bringing conical portion 92 of the skirt into contact with the interior surface of the body lumen to obstruct the flow of bodily fluid, e.g., blood, past the catheter. If a skirt is included on distal portion 158 of catheter 154, a sleeve (not shown in this Figure) or other retainer will be required to maintain the skirt in its furled state until distal port 162 has been positioned at the site where fluid will be administered to the body lumen. The sleeve can then be withdrawn from the skirt to enable it to unfurl into sealing contact with the interior surface of the body lumen and will preferably be designed to split near side tube 48 upon removal from the patient's body. Exemplary Application of the Present Invention FIGURE 14 illustrates how a multi-cannula catheter assembly 161 that is provided with a skirt 100 around both an inner catheter 164 and an outer catheter 163 is advanced through a blood vessel 151 with both of the skirts in a furled state. In an illustrative application of the present invention, it is used for treating both vascular disease and ischemic tissue of a patient's lower limb and providing treatment of an infected ulcer in the patient's foot due to poor circulation caused by some form of metabolic or vascular disease or associated complications of these diseases. Multi-cannula catheter assembly 161 is inserted into blood vessel 151 through an introducer after blood flow through the blood vessel has been impeded by a pressure cuff (not shown) applied to the patient's leg. When the pressure cuff is inflated, the physiological valves in the veins of the leg will relax in the open position, and blood flow through the vein in which the multi-cannula catheter assembly is inserted will be substantially reduced. Using a standard percutaneous access procedure, a guide wire is threaded in retrograde fashion across valves in the vein and advanced to a site of the intended treatment in the foot. The multi-cannula catheter assembly is advanced coaxially over the guide wire to the furthest distal treatment site in the foot. In FIGURES 14 and 15, the arrow at the left-hand side of the blood vessel indicates the normal direction of blood flow through the vessel. To maintain skirt 100 in its furled state around inner catheter 164, the inner catheter is positioned with conical portion 102 of the skirt substantially within a distal opening 168 of a distal end 166 of the outer catheter. The overlying portion of distal end 166 on the outer catheter maintains conical portion 102 of skirt 100 furled so long as the inner catheter is substantially contained within the guide lumen of outer catheter 163. Skirt 100 on outer catheter 163 is retained in its furled state by use of a sleeve 170 that is slipped over the skirt, generally retaining conical portion 102 of the skirt against the outer surface of outer catheter 163. Sleeve 170 can be sufficiently long to extend proximally outside the patient's body, but in this embodiment is connected to a line 174 where the line is fused to the sleeve at a point 172. Line 174 extends back into outer catheter 163 and through one of the lumens of the outer catheter to a point outside the patient's body. Thus, the multi-cannula catheter assembly is advanced through blood vessel 151 over the guide wire so as to bring distal port 44 of inner catheter 164 to a desired position at the treatment site in the foot, as illustrated in FIGURE 15. The inner catheter is then held constant at that position while the outer catheter and sleeve 170 are drawn back from the inner catheter as a single unit, enabling conical portion 102 of skirt 100 on the inner catheter to achieve its furled state, bringing the distal portion of skirt 100 into contact with the inner surface of blood vessel 151. It should also be noted that although not shown, a sleeve like sleeve 170 can be provided over a skirt disposed on the inner catheter to keep that skirt furled until the sleeve is pulled back from the skirt. Thus, providing a sleeve over the skirt on the inner catheter is an alternative to using the outer catheter to keep the skirt on the inner catheter furled. From the disposition illustrated in FIGURE 15, the outer catheter and sleeve 170 are then drawn back over the inner catheter to the site at the mid-calf in the patient's leg, for example, where vascular disease has occurred in adjacent tissue and is impeding blood flow to the foot, which may be a causative factor in causing the infected foot ulcer. This position is where the fluid is to be administered through distal port 168 on the outer catheter. Once this position is achieved, line 174 is drawn back, pulling sleeve 170 away from skirt 100 on the outer catheter, enabling the conical portion of the skirt to come into contact with the inner surface of blood vessel 151 to prevent any further blood flow past that point within the blood vessel. At this time, the pressure cuff can be released, allowing blood to flow through the blood vessel up to skirt 100 on the inner catheter. Different medicinal fluids can then be separately infused into blood vessel 151 through distal ports 44 and 168, respectively, to administer the fluid to the sites in the foot and in the mid-calf of the leg. For example, an antibiotic can be administered to distal port 44 through the inner catheter to treat the infected foot ulcer, while an appropriate drug is delivered through distal port 168 in outer catheter 163 to treat the vascular disease in the adjacent diseased and/or ischemic tissue. Another lumen in the inner and/or outer catheters can be used for infusing other fluids, such as genetically modified agents or growth factor into same of other treatment sites to aid in the revascularization of the foot and/or leg or to enhance the healing factors at the different treatment sites. It should be noted that the infusion of fluid through the outer catheter into the vein within the mid-calf, in this example, appears to be conveyed through intervening tissue in retrograde flow to reach the diseased vasculature in the adjacent tissue. The unfurled skirts increase the residence time of the medicinal fluids that are infused to encourage such microcirculatory migration of the medicinal fluids. After use of the catheter has been completed, the inner catheter is drawn back through blood vessel 151 until sleeve 100 on the inner catheter is encompassed within distal port 168, again causing sleeve 100 on the inner catheter to be furled within the outer catheter. In contrast, sleeve 100 on outer catheter 163 is not furled, but instead, is drawn back through the blood vessel in its furled state, since sleeve 170 cannot be readily forced back over skirt 100 on the outer catheter. In the event that the skirt on the outer catheter is not required, it should be noted that skirt 100 on the inner catheter can be again drawn back into distal port 168 on the outer catheter to furl the skirt, thereby enabling the multi-cannula catheter assembly to be repositioned to a different site within blood vessel 151. Once the new position for the distal port of the inner catheter is achieved, the outer catheter can again be drawn back from the skirt, enabling the skirt on the inner catheter to unfurl and obstruct blood flow through blood vessel 151. It should be noted that when blood flow through blood vessel 151 is interrupted by application of the pressure cuff to the leg, the natural physiological valves 176 within the blood vessel tend to open and thus provide little resistance to the passage of the various elements of the multi-cannula catheter assembly through the blood vessel (vein). There are several advantages to a multi-cannula catheter assembly in accord with the present invention. It is possible to deliver medical agents or fluids in veins, avoiding the need to cross arterial diseased sites with the catheter tip. Further, the fluids can be delivered through the distal ports of the different catheters even though ischemic degradation of an artery has caused circulation to be substantially reduced in the veins that convey blood back to the heart. The obstructive skirts can be deployed and then again furled, leaving no shaφ edges exposed, producing a low-profile cross section for the catheter assembly when it is necessary to move it within the body lumen. It is unnecessary to provide an inner lumen on the catheter assembly to convey an inflation fluid to deploy an obstructive element such as a balloon, as in prior art devices. Most of the embodiments for the skirt discussed above do not cause dilation of the body lumen and are not abrasive to the endothelial layer within a blood vessel or other body lumen, thereby minimizing the risk of damage to the vessel and reducing the likelihood of thrombus formation. Also, since the skirts are generally conformal, they do not require sizing for different applications to minimize the risk of vessel dilation. Although the present invention has been described in connection with the preferred form of practicing it, those of ordinary skill in the art will understand that many modifications can be made thereto within the scope of the claims that follow. Accordingly, it is not intended that the scope of the invention in any way be limited by the above description, but instead be determined entirely by reference to the claims that follow.

Claims: The invention in which an exclusive right is claimed is defined by the following: 1. A catheter assembly that is usable for administering a first liquid to a first site in a body lumen of a patient and a second liquid to a second site in the body lumen, the second site being substantially spaced apart from the first site, comprising: (a) a first tube that is flexible and elongate, said first tube having a lumen and a proximal port adapted to introduce the first liquid into the lumen, and a distal port coupled in fluid communication with the lumen and thus adapted to supply the first liquid to the first site; (b) a guide lumen extending along at least a portion of a length of the first tube; and (c) a second tube that is flexible and elongate, having a lumen extending therethrough, said lumen coupling a proximal port in fluid communication with a distal port, said second tube being smaller in cross- sectional size than the guide lumen of the first tube, enabling: (i) a position of the distal port of the second tube to be adjusted in the body lumen relative to a position of the distal port of the first tube; (ii) the first liquid to be administered to the first site through the lumen and the distal port of the first tube; and (iii) the second liquid to be administered to the second site through the lumen and the distal port of the second tube. 2. The catheter assembly of Claim 1 , wherein the distal port of the first tube is disposed in a wall of the first tube. 3. The catheter assembly of Claim 1, wherein the lumen of the first tube through which the first liquid is administered to the first site is the guide lumen. 4. The catheter assembly of Claim 3, wherein the distal port of the first tube comprises a gap defined between the outer surface of the second tube and an inner surface of the guide lumen of the first tube. 5. The catheter assembly of Claim 1, further comprising a seal disposed at a proximal end of the guide lumen, said seal being sized to fit sealingly around an exterior surface of the second tube so that said second tube readily slides through the guide lumen and including an adjustable compression fitting that is engaged to lock the second tube at a desired position in the guide lumen. 6. The catheter assembly of Claim 1, wherein the second tube includes at least one additional lumen extending longitudinally therethrough. 7. The catheter assembly of Claim 1, wherein the first tube includes at least one additional lumen extending longitudinally therethrough. 8. The catheter assembly of Claim 1, further comprising a skirt that includes a distal end and a proximal end, the proximal end of the skirt being attached in sealing relationship around an outer surface of at least one of the first tube and the second tube, adjacent to its distal end, the distal end of the skirt being adapted to seal against an internal surface of a body lumen in which the catheter apparatus is inserted, to at least partially prevent body fluid from flowing proximally past the distal end of said at least one of the first tube and the second tube. 9. The catheter assembly of Claim 8, wherein the skirt includes a biasing element that acts on the skirt, causing a portion of the skirt to expand radially outward into sealing relationship with the inner wall of the body lumen when the skirt is enabled to unfurl. 10. The catheter assembly of Claim 8, further comprising a sleeve that encompasses the skirt, keeping the skirt furled about the outer surface of said at least one of the first tube and the second tube while the catheter assembly is being advanced through a body lumen, said sleeve being withdrawn from the skirt so that the skirt then unfurls and the distal end of the skirt is able to form a sealing relationship with the inner surface of the body lumen. 11. A method for administering first and second fluids respectively to disparate first and second sites within a body lumen, comprising the steps of: (a) providing a catheter assembly that includes a first tube that is flexible and has a guide lumen in which is disposed a second tube that is flexible and includes a lumen, each of said first and second tubes including a proximal port and a distal port; (b) inserting distal ends of the first tube and the second tube into the body lumen and advancing the catheter assembly through the body lumen, bringing the distal port of the first tube proximate the first site within the body lumen; (c) either before or after step (b), sliding the second tube through the guide lumen of the first tube so that the distal port of the second tube is advanced substantially beyond the distal port of the first tube and so that a spacing between the distal ports of the first and second tubes is substantially equal to that between the first site and the second site in the body lumen; (d) infusing the first liquid to the first site through the guide lumen and distal port of the first tube; and (e) infusing the second liquid to the second site through the lumen and distal port of the second tube. 12. The method of Claim 11, wherein the step of advancing the catheter assembly through the body lumen comprises the steps of: (a) advancing a guide wire through the body lumen until a distal end of the guide wire is proximate the second site; and (b) advancing the catheter assembly into the body lumen along the guide wire, the guide wire passing through the lumen of the second catheter. 13. The method of Claim 12, further comprising the steps of: (a) substantially interrupting bodily fluid flow through the body lumen while the catheter assembly is being advanced through the body lumen; and (b) enabling the flow of the bodily fluid through the body lumen after the distal port of the first tube is disposed proximate the first site and the distal port of the second tube is disposed proximate the second site. 14. The method of Claim 13, further comprising the step of enabling deployment of an obstructive skirt included on the catheter assembly to block the flow of the bodily fluid through the body lumen past at least one of a distal end of the first tube and a distal end of the second tube, after the step of advancing the catheter assembly through the body lumen. 15. The method of Claim 14, wherein the step of enabling deployment of the obstructive skirt comprises the step of releasing the obstructive skirt so that a biasing force acting on the obstructive skirt causes it to unfurl within the body lumen, the obstructive skirt being attached to said at least one of the distal end of the first tube and the distal end of the second tube, said obstructive skirt forming a seal against an inner surface of the body lumen to interrupt the flow of the bodily fluid through the body lumen. 16. The method of Claim 15, further comprising the step of maintaining the obstructive skirt in a furled state so that it is retained against an outer surface of said at least one of the first tube and the second tube during the step of advancing the catheter assembly through the body lumen, said obstructive skirt being enabled to unfurl from around said outer surface after at least the distal port of the first tube is disposed proximate the first site. 17. The method of Claim 16, wherein the step of maintaining the obstructive skirt in the furled state comprises the step of encompassing the obstructive skirt furled within a sleeve; and wherein the step of releasing the obstructive skirt comprises the step of pulling the sleeve away from the furled obstructive skirt, enabling said skirt to unfurl. 18. The method of Claim 16, wherein the obstructive skirt is attached to the second tube, and wherein the step of maintaining the obstructive skirt in the furled state comprises the step of encompassing the obstructive skirt furled within the guide lumen, said step of releasing the obstructive skirt comprising the step of withdrawing the first tube relative to the second tube, until the obstructive skirt is released from within the guide lumen and enabled to unfurl. 19. The method of Claim 18, further comprising the step of advancing the first tube over the obstructive skirt, causing it to furl within the guide lumen, to enable the second tube to be repositioned within the body lumen by moving the catheter assembly. 20. An adjustable catheter assembly for administering fluids to disparate treatment sites within a body lumen, comprising: (a) an outer catheter having a guide lumen defining a fluid path extending between a proximal port and a distal port of the outer catheter; (b) an inner catheter having a lumen defining a fluid path extending between a proximal port and a distal port of the inner catheter, said inner catheter being disposed within the guide lumen of the outer catheter and slidably movable through the guide lumen to vary a spacing between the distal port of the outer catheter and the distal port of the inner catheter, said inner catheter being positionable in the guide lumen so that the spacing between the distal ports of the inner and the outer catheters is substantially equal to that between the disparate treatment sites; and (c) a skirt that is attached at least at a proximal end thereof to an outer surface of the outer catheter, adjacent to, but proximal of the distal port of the outer catheter, said skirt having another portion that is biased to expand radially outward into sealing contact with an inner surface of the body lumen to at least partially obstruct a flow of bodily fluid through the body lumen, so that fluids delivered through the distal ports are not flushed from the treatment sites by bodily fluid flowing through the body lumen. 21. The adjustable catheter assembly of Claim 20, wherein the distal port in the outer catheter is disposed in a wall of the outer catheter. 22. The adjustable catheter assembly of Claim 21, wherein the distal port is encompassed by the skirt so that the fluid flowing from the distal port into the body lumen is directed against an inner surface of the skirt and does not directly impact an interior surface of the body lumen. 23. The adjustable catheter assembly of Claim 20, wherein the distal port in the outer catheter comprises a gap between an outer surface of the inner catheter and an inner surface of the outer catheter. 24. The adjustable catheter assembly of Claim 20, further comprising an elastomeric spring that biases the other portion of the skirt radially outward. 25. The adjustable catheter assembly of Claim 24, wherein the elastomeric spring comprises a helical coil disposed radially within an interior of the skirt. 26. The adjustable catheter assembly of Claim 24, wherein the elastomeric spring comprises a super elastic alloy having a radially expanded shape. 27. The adjustable catheter assembly of Claim 20, wherein the skirt has a lily-like shape into which the skirt is deployed by a stiffening member that extends at least around a portion of an edge of the skirt, an outer surface of the skirt then sealing against the inner surface of the body lumen to at least partially obstruct the flow of the bodily fluid through the body lumen without causing substantial radial dilation of the body lumen. 28. The adjustable catheter assembly of Claim 20, further comprising a plurality of struts that extend distally from a distal edge of the skirt and are connected to the outer surface of the outer catheter, said plurality of struts preventing the skirt from prolapsing. 29. The adjustable catheter assembly of Claim 20, further comprising an expandable rib structure coupled to a distal end of the skirt, said expandable rib structure being coupled to a line that extends through a lumen in the outer catheter and out from the proximal end of the outer catheter, a force exerted to pull said line from the outer catheter causing the distal end of the skirt to be forced radially outward into contact with the interior surface of the body lumen. 30. The adjustable catheter assembly of Claim 20, wherein the skirt comprises a generally spherically shaped structure that is collapsed until released and enabled to expand outwardly into contact with the inner surface of the body lumen. 31. The adjustable catheter assembly of Claim 20, further comprising a sleeve that is disposed around the skirt to retain the skirt in a furled state, said sleeve keeping the skirt furled closely around the outer surface of the outer catheter while the outer catheter is advanced through the body lumen, said sleeve including a line that is adapted to extend outside the body lumen, enabling the sleeve to be pulled back from the skirt so that the biasing force causes the skirt to unfurl, obstructing the flow of the bodily fluid through the body lumen. 32. The adjustable catheter assembly of Claim 20, further comprising a seal disposed around the inner catheter at a proximal end of the guide lumen, said seal enabling the inner catheter to be slidably moved while sealing against fluid flow from the guide lumen. 33. An adjustable catheter assembly for administering fluids to disparate treatment sites within a body lumen, comprising: (a) an outer catheter having a guide lumen defining a fluid path extending between a proximal port and a distal port of the outer catheter; (b) an inner catheter having a lumen defining a fluid path extending between a proximal port and a distal port of the inner catheter, said inner catheter being disposed within the guide lumen of the outer catheter and slidably movable through the guide lumen to vary a spacing between the distal port of the outer catheter and the distal port of the inner catheter, said inner catheter being positionable in the guide lumen so that the spacing between the distal ports of the inner and the outer catheters is substantially equal to that between the disparate treatment sites; and (c) a skirt that is attached at a proximal end thereof to an outer surface of the inner catheter, adjacent to, but proximal of the distal port of the inner catheter, said skirt having a distal end that is biased to expand radially outward into sealing contact with an inner surface of the body lumen to at least partially obstruct a flow of bodily fluid through the body lumen, so that fluids delivered through the distal ports are not flushed from the treatment sites by bodily fluid flowing through the body lumen. 34. The adjustable catheter assembly of Claim 33, wherein the distal port in the inner catheter is disposed in a wall of the inner catheter, adjacent to a distal end of the inner catheter. 35. The adjustable catheter assembly of Claim 34, wherein the distal port is encompassed by the skirt so that the fluid flowing from the distal port into the body lumen is directed against an inner surface of the skirt and does not directly impact an interior surface of the body lumen. 36. The adjustable catheter assembly of Claim 33, wherein the distal port in the outer catheter comprises a gap between an outer surface of the inner catheter and an inner surface of the outer catheter. 37. The adjustable catheter assembly of Claim 33, further comprising an elastomeric spring that biases the other portion of the skirt radially outward. 38. The adjustable catheter assembly of Claim 37, wherein the elastomeric spring comprises a helical coil disposed radially within an interior of the skirt. 39. The adjustable catheter assembly of Claim 37, wherein the elastomeric spring comprises a super elastic alloy having a radially expanded shape. 40. The adjustable catheter assembly of Claim 33, wherein the skirt has a lily-like shape into which the skirt is deployed by a stiffening member that extends at least around a portion of an edge of the skirt, an outer surface of the skirt then sealing against the inner surface of the body lumen to at least partially obstruct the flow of the bodily fluid through the body lumen without causing substantial radial dilation of the body lumen. 41. The adjustable catheter assembly of Claim 33, further comprising a plurality of struts that extend distally from a distal edge of the skirt and are connected to the outer surface of the inner catheter, said plurality of struts preventing the skirt from prolapsing. 42. The adjustable catheter assembly of Claim 33, further comprising a Malecot structure coupled to a distal end of the skirt, said Malecot structure including a line that extends through a lumen in the inner catheter and out from the proximal end of the inner catheter, a force exerted to pull said line from the inner catheter causing the distal end of the skirt to be forced radially outward into contact with the interior surface of the body lumen. 43. The adjustable catheter assembly of Claim 33, wherein the skirt comprises a generally spherically shaped structure that is collapsed until released and enabled to expand outwardly into contact with the inner surface of the body lumen. 44. The adjustable catheter assembly of Claim 33, wherein the guide lumen encloses the skirt, keeping the skirt furled until the inner catheter is advanced relative to the outer catheter sufficiently far so that the skirt is released and is unfurled by the biasing force. 45. The adjustable catheter assembly of Claim 33, further comprising a seal disposed around the inner catheter at a proximal end of the guide lumen, said seal enabling the inner catheter to be slidably moved while sealing against fluid flow from the guide lumen. 46. A catheter for infusing a liquid into a body lumen, comprising: (a) a tube that is elongate and flexible, said tube having a lumen coupling a proximal port and a distal port in fluid communication, the liquid being applied through the proximal port and administered into the body lumen through the distal port; and (b) a skirt comprising a generally flexible sheet of a material having a proximal end that is attached around an outer surface of the tube, proximate but adjacent to the distal port, another portion of said skirt being adapted to seal against an inner surface of the body lumen to at least partially obstruct a flow of a bodily fluid therethrough, said skirt preventing the liquid from being washed away from the distal port by the bodily fluid flowing through the body lumen so that the liquid is retained at a site generally proximate to the distal port. 47. The catheter of Claim 46, wherein the distal port in the lumen is disposed in a wall of the catheter, adjacent to a distal end of the catheter. 48. The catheter of Claim 47, wherein the distal port is encompassed by the skirt so that the fluid flowing from the distal port into the body lumen is directed against an inner surface of the skirt and does not directly impact an interior surface of the body lumen. 49. The catheter of Claim 46, further comprising an elastomeric spring that biases the other portion of the skirt radially outward. 50. The catheter of Claim 49, wherein the elastomeric spring comprises a helical coil disposed radially within an interior of the skirt. 51. The catheter of Claim 49, wherein the elastomeric spring comprises a super elastic alloy having a radially expanded shape. 52. The catheter of Claim 46, wherein the skirt has a lily-like shape, an outer surface of the skirt comprising the other portion of the skirt that seals against the inner surface of the body lumen to at least partially obstruct the flow of the bodily fluid through the body lumen without causing substantial radial dilation of the body lumen. 53. The catheter of Claim 46, further comprising a plurality of struts that extend distally from a distal edge of the skirt and are connected to the outer surface of the catheter, said plurality of struts preventing the skirt from prolapsing. 54. The catheter of Claim 46, further comprising a Malecot structure coupled to a distal end of the skirt, said Malecot structure including a line that extends through a lumen in the catheter and out from the proximal end of the catheter, a force exerted to pull said line from the catheter causing the distal end of the skirt to be forced radially outward into contact with the interior surface of the body lumen. 55. The catheter of Claim 46, wherein the skirt comprises a generally spherically shaped structure that is collapsed until released and enabled to expand outwardly into contact with the inner surface of the body lumen. 56. The catheter of Claim 46, further comprising a sleeve that is disposed over the skirt while the catheter is being advanced through the body lumen, said sleeve retaining the skirt closely against the outer surface of the catheter. 57. The catheter of Claim 56, further comprising a line connected to the sleeve, said line being adapted to extend outside the body lumen to enable the sleeve to be pulled from the skirt, thereby enabling the skirt to unfurl so that it obstructs the flow of the bodily fluid through the body lumen. 58. The catheter of Claim 46, further comprising an additional lumen extending through the catheter. AMENDED CLAIMS [received by the International Bureau on 12 January 2001 (12.01.01) original claims 1, 8, 33, 37, 41-42, 46, 49 and 53-54 amended; new claim 59 added; remaining claims unchanged (6 pages)] The invention in which an exclusive right is claimed is defined by the following: 1. A catheter assembly that is usable for administering a first liquid to a first site in a body lumen of a patient and a second liquid to a second site in the body lumen, the second site being substantially spaced apart from the first site, comprising: (a) a first tube that is flexible and elongate, said first tube having a lumen and a proximal port adapted to introduce the first liquid into the lumen, and a distal port coupled in fluid communication with the lumen and thus adapted to supply the first liquid to the first site; (b) a guide lumen extending along at least a portion of a length of the first tube; (c) a second tube that is flexible and elongate, having a lumen extending therethrough, said lumen coupling a proximal port in fluid communication with a distal port, said second tube being smaller in cross- sectional size than the guide lumen of the first tube, enabling: (i) a position of the distal port of the second tube to be adjusted in the body lumen relative to a position of the distal port of the first tube; (ii) the first liquid to be administered to the first site through the lumen and the distal port of the first tube; and (iii) the second liquid to be administered to the second site through the lumen and the distal port of the second tube; and (d) means for preventing said first liquid and said second liquid from mixing. 2. The catheter assembly of Claim 1, wherein the distal port of the first tube is disposed in a wall of the first tube. 3. The catheter assembly of Claim 1, wherein the lumen of the first tube through which the first liquid is administered to the first site is the guide lumen. 4. The catheter assembly of Claim 3, wherein the distal port of the first tube comprises a gap defined between the outer surface of the second tube and an inner surface of the guide lumen of the first tube. 5. The catheter assembly of Claim 1, further comprising a seal disposed at a proximal end of the guide lumen, said seal being sized to fit sealingly around an exterior surface of the second tube so that said second tube readily slides through the guide lumen and including an adjustable compression fitting that is engaged to lock the second tube at a desired position in the guide lumen. 6. The catheter assembly of Claim 1, wherein the second tube includes at least one additional lumen extending longitudinally therethrough. 7. The catheter assembly of Claim 1, wherein the first tube includes at least one additional lumen extending longitudinally therethrough. 8. The catheter assembly of Claim 1, wherein said means comprises a skirt that includes a distal end and a proximal end, the proximal end of the skirt being attached in sealing relationship around an outer surface of at least one of the first tube and the second tube, adjacent to its distal end, the distal end of the skirt being adapted to seal against an internal surface of a body lumen in which the catheter apparatus is inserted, to at least partially prevent body fluid from flowing proximally past the distal end of said at least one of the first tube and the second tube, thereby preventing said first liquid and said second liquid from mixing. 9. The catheter assembly of Claim 8, wherein the skirt includes a biasing element that acts on the skirt, causing a portion of the skirt to expand radially outward into sealing relationship with the inner wall of the body lumen when the skirt is enabled to unfurl. 10. The catheter assembly of Claim 8, further comprising a sleeve that encompasses the skirt, keeping the skirt furled about the outer surface of said at least one of the first tube and the second tube while the catheter assembly is being advanced through a body lumen, said sleeve being withdrawn from the skirt so that the skirt then unfurls and the distal end of the skirt is able to form a sealing relationship with the inner surface of the body lumen. 11. A method for administering first and second fluids respectively to disparate first and second sites within a body lumen, comprising the steps of: (a) providing a catheter assembly that includes a first tube that is flexible and has a guide lumen in which is disposed a second tube that is flexible and includes a lumen, each of said first and second tubes including a proximal port and a distal port; (b) inserting distal ends of the first tube and the second tube into the body lumen and advancing the catheter assembly through the body lumen, bringing the distal port of the first tube proximate the first site within the body lumen; (c) either before or after step (b), sliding the second tube through the guide lumen of the first tube so that the distal port of the second tube is advanced substantially beyond the distal port of the first tube and so that a spacing between the distal ports of the first and second tubes is substantially equal to that between the first site and the second site in the body lumen; (d) infusing the first liquid to the first site through the guide lumen and distal port of the first tube; and (e) infusing the second liquid to the second site through the lumen and distal port of the second tube. sleeve keeping the skirt furled closely around the outer surface of the outer catheter while the outer catheter is advanced through the body lumen, said sleeve including a line that is adapted to extend outside the body lumen, enabling the sleeve to be pulled back from the skirt so that the biasing force causes the skirt to unfurl, obstructing the flow of the bodily fluid through the body lumen. 32. The adjustable catheter assembly of Claim 20, further comprising a seal disposed around the inner catheter at a proximal end of the guide lumen, said seal enabling the inner catheter to be slidably moved while sealing against fluid flow from the guide lumen. 33. An adjustable catheter assembly for administering fluids to disparate treatment sites within a body lumen, comprising: (a) an outer catheter having a guide lumen defining a fluid path extending between a proximal port and a distal port of the outer catheter; (b) an inner catheter having a lumen defining a fluid path extending between a proximal port and a distal port of the inner catheter, said inner catheter being disposed within the guide lumen of the outer catheter and slidably movable through the guide lumen to vary a spacing between the distal port of the outer catheter and the distal port of the inner catheter, said inner catheter being positionable in the guide lumen so that the spacing between the distal ports of the inner and the outer catheters is substantially equal to that between the disparate treatment sites; and (c) means for ensuring that fluids delivered through the distal ports are not flushed from the treatment sites by bodily fluid flowing through the body lumen, said means comprising a skirt that is attached at a proximal end thereof to an outer surface of the inner catheter, adjacent to, but proximal of the distal port of the inner catheter, said skirt having a distal end that is biased to expand radially outward into sealing contact with an inner surface of the body lumen to at least partially obstruct a flow of bodily fluid through the body lumen, so that fluids delivered through the distal ports are not flushed from the treatment sites by bodily fluid flowing through the body lumen. 34. The adjustable catheter assembly of Claim 33, wherein the distal port in the inner catheter is disposed in a wall of the inner catheter, adjacent to a distal end of the inner catheter. 35. The adjustable catheter assembly of Claim 34, wherein the distal port is encompassed by the skirt so that the fluid flowing from the distal port into the body lumen is directed against an inner surface of the skirt and does not directly impact an interior surface of the body lumen. 36. The adjustable catheter assembly of Claim 33, wherein the distal port in the outer catheter comprises a gap between an outer surface of the inner catheter and an inner surface of the outer catheter. 37. The adjustable catheter assembly of Claim 33, wherein said means further comprises an elastomeric spring that biases the other portion of the skirt radially outward. 38. The adjustable catheter assembly of Claim 37, wherein the elastomeric spring comprises a helical coil disposed radially within an interior of the skirt. 39. The adjustable catheter assembly of Claim 37, wherein the elastomeric spring comprises a super elastic alloy having a radially expanded shape. 40. The adjustable catheter assembly of Claim 33, wherein the skirt has a lily-like shape into which the skirt is deployed by a stiffening member that extends at least around a portion of an edge of the skirt, an outer surface of the skirt then sealing against the inner surface of the body lumen to at least partially obstruct the flow of the bodily fluid through the body lumen without causing substantial radial dilation of the body lumen. 41. The adjustable catheter assembly of Claim 33, wherein said means further comprises a plurality of struts that extend distally from a distal edge of the skirt and are connected to the outer surface of the inner catheter, said plurality of struts preventing the skirt from prolapsing. 42. The adjustable catheter assembly of Claim 33, wherein said means further comprises a Malecot structure coupled to a distal end of the skirt, said Malecot structure including a line that extends through a lumen in the inner catheter and out from the proximal end of the inner catheter, a force exerted to pull said line from the inner catheter causing the distal end of the skirt to be forced radially outward into contact with the interior surface of the body lumen. 43. The adjustable catheter assembly of Claim 33, wherein the skirt comprises a generally spherically shaped structure that is collapsed until released and enabled to expand outwardly into contact with the inner surface of the body lumen. 44. The adjustable catheter assembly of Claim 33, wherein the guide lumen encloses the skirt, keeping the skirt furled until the inner catheter is advanced relative to the outer catheter sufficiently far so that the skirt is released and is unfurled by the biasing force. 45. The adjustable catheter assembly of Claim 33, further comprising a seal disposed around the inner catheter at a proximal end of the guide lumen, said seal enabling the inner catheter to be slidably moved while sealing against fluid flow from the guide lumen. 46. A catheter for infusing a liquid into a body lumen, comprising: (a) a tube that is elongate and flexible, said tube having a lumen coupling a proximal port and a distal port in fluid communication, the liquid being applied through the proximal port and administered into the body lumen through the distal port; and (b) means for preventing the liquid being applied from being washed away from said distal port by a bodily fluid flowing through the body lumen, said means comprising a skirt, said skirt comprising a generally flexible sheet of a material having a proximal end that is attached around an outer surface of the tube, proximate but adjacent to the distal port, another portion of said skirt being adapted to seal against an inner surface of the body lumen to at least partially obstruct a flow of a bodily fluid therethrough, said skirt preventing the liquid from being washed away from the distal port by the bodily fluid flowing through the body lumen so that the liquid is retained at a site generally proximate to the distal port. 47. The catheter of Claim 46, wherein the distal port in the lumen is disposed in a wall of the catheter, adjacent to a distal end of the catheter. 48. The catheter of Claim 47, wherein the distal port is encompassed by the skirt so that the fluid flowing from the distal port into the body lumen is directed against an inner surface of the skirt and does not directly impact an interior surface of the body lumen. 49. The adjustable catheter assembly of Claim 46, wherein said means further comprises an elastomeric spring that biases the other portion of the skirt radially outward. 50. The catheter of Claim 49, wherein the elastomeric spring comprises a helical coil disposed radially within an interior of the skirt. 51. The catheter of Claim 49, wherein the elastomeric spring comprises a super elastic alloy having a radially expanded shape. 52. The catheter of Claim 46, wherein the skirt has a lily-like shape, an outer surface of the skirt comprising the other portion of the skirt that seals against the inner surface of the body lumen to at least partially obstruct the flow of the bodily fluid through the body lumen without causing substantial radial dilation of the body lumen. 53. The catheter of Claim 46, wherein said means further comprises a plurality of struts that extend distally from a distal edge of the skirt and are connected to the outer surface of the catheter, said plurality of struts preventing the skirt from prolapsing. 54. The catheter of Claim 46, wherein said means further comprises a Malecot structure coupled to a distal end of the skirt, said Malecot structure including a line that extends through a lumen in the catheter and out from the proximal end of the catheter, a force exerted to pull said line from the catheter causing the distal end of the skirt to be forced radially outward into contact with the interior surface of the body lumen. 55. The catheter of Claim 46, wherein the skirt comprises a generally spherically shaped structure that is collapsed until released and enabled to expand outwardly into contact with the inner surface of the body lumen. 56. The catheter of Claim 46, further comprising a sleeve that is disposed over the skirt while the catheter is being advanced through the body lumen, said sleeve retaining the skirt closely against the outer surface of the catheter. 57. The catheter of Claim 56, further comprising a line connected to the sleeve, said line being adapted to extend outside the body lumen to enable the sleeve to be pulled from the skirt, thereby enabling the skirt to unfurl so that it obstructs the flow of the bodily fluid through the body lumen. 58. The catheter of Claim 46, further comprising an additional lumen extending through the catheter. 59. The catheter assembly of Claim 1 , wherein said means comprises a portion of the second tube having a length that enables the distal port of the second tube to be positioned sufficiently far away the distal port of the first tube so as to ensure that no mixing of said first liquid and said second liquid occurs.

Inventors: GORDON MARY JO, WILCOX ROBERT L, GORDON, MARY, JO, WILCOX, ROBERT, L.
Applicants: PHARMASPEC CORP, PHARMASPEC CORPORATION
Application year: 2000
Main classification: A61M5
IPC codes: A61B17, A61M25