Abstract:
A catheter system includes a catheter having a proximal end, a distal end, and a lumen extending therein. An elongate mender slidably disposed in the lumen has a distal end located proximate the distal end of the catheter. An administering tip is disposed at the distal end of the catheter and is configured to express a bolus of liquid in response to positive pressure in a distal portion of the lumen created by movement of the elongate member distally in the lumen. The present invention also includes a method of administering a liquid to a treatment site. The distal end of the catheter is transluminally positioned proximate the treatment site. The catheter is charged by placing a bolus of the liquid in a distal end of the lumen between a distal tip of the catheter and a distal end of the elongate member. The elongate member is then moved distally within the lumen to express the bolus from the distal end of the catheter.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Ser. No. 08/982,220, filed Dec. 1, 1997 and which issued as U.S. Pat. No. 6,050,968. 
     INCORPORATION BY REFERENCE 
     Reference is made to the following patent applications which are hereby fully incorporated by reference: 
     U.S. patent Ser. No. 08/308,025, filed on Sep. 16, 1994 entitled “BALLOON CATHETER WITH IMPROVED PRESSURE SOURCE”, now U.S. Pat. No. 5,545,133. 
     U.S. patent Ser. No. 08/586,514 filed on Jan. 16, 1996 entitled “BALLOON CATHETER WITH IMPROVED PRESSURE SOURCE”, now U.S. Pat. No. 5,695,468 
     U.S. patent Ser. No. 08/619,375 filed on May 21, 1996 entitled “BALLOON CATHETER WITH IMPROVED PRESSURE SOURCE”, now U.S. Pat. No. 5,728,064 and 
     U.S. patent Ser. No. 08/812,390 filed on Mar. 5, 1997 entitled “BALLOON CATHETER WITH IMPROVED PRESSURE SOURCE, now U.S. Pat. No. 5,785,685. 
     All of the above-referenced patent applications are assigned to the same assignee as the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention deals with catheters. More specifically, the present invention deals with delivery of a small bolus of liquid with a catheter. 
     A wide variety of different mechanisms and techniques have been developed in order to treat coronary disease. However, such techniques and devices are typically drawn to the physical manipulation of biological tissues, such as heart tissue, or other vascular tissue within the vascular system. 
     For example, some treatment techniques are drawn to the physical removal or dilation of restrictions (stenoses and total occlusions) in the vasculature. Techniques for dealing with this type of disease have included percutaneous transluminal coronary angioplasty (PTCA) in which an angioplasty balloon catheter is inserted into the body via the femoral artery and positioned across a restriction in an artery. The balloon is inflated to widen the restriction and restore blood flow to portions of the heart muscle previously deprived of oxygenated blood. Implantation of stents using PTCA is also a common technique for opening an arterial restriction. 
     Another technique for dealing with vascular disease includes coronary artery bypass graft (CABG) procedures. Such procedures typically include the placement of a graft at a desired location in the vasculature to supplement blood flow to the area previously deprived of blood for (or provided with reduced blood flow) due to the vascular restriction. One common type of CABG procedure involves placement of a saphenous vein graft (SVG) between the ascending aorta proximal of the restriction, and a region in the restricted vessel distal of the restriction. 
     Another technique for dealing with vascular disease includes an atherectomy procedure. In an atherectomy procedure, an atherectomy device is placed in the vasculature proximate the restriction. The atherectomy device is deployed to physically cut away, abrade, or otherwise physically remove, the occlusive material from the restricted vessel. The portions of the restriction which are severed by the atherectomy device are subsequently removed by aspiration, or by another suitable means. 
     Another technique called transluminal myocardial revascularization is also receiving attention in the medical community as an acceptable therapy. 
     Various drug therapies have also been developed. Such therapies have been used in place of, and in conjunction with, the above mentioned therapies under certain circumstances. For example, during grafting procedures, it may be desirable to deliver drugs to the graft site which inhibit the formation of thrombus. In addition, some drug therapies have been developed which involve the delivery of drugs directly to the heart tissue. With recent advancements in the pharmaceutical industry, other drug therapies have also become desirable. Some such recent pharmaceutical developments include the development of gene therapy drugs, such as growth factors. 
     A transluminal technique for delivering the drugs, along with the various types of known positioning and visualization techniques commonly used with transluminal treatments, can be highly desirable. The drug therapies typically require site-specific administration of the drug. Transluminal techniques can be effectively used to deliver a liquid material to a selected site in the vasculature. 
     However, drug therapies, can be prohibitively expensive. For example, newly developed drugs are commonly extremely expensive and can only be administered in any pragmatic fashion in very low volumes. Typically, such drugs only need to be administered to the vascular site being treated. However, there is no technique available to date by which the site to be treated can be accessed transluminally with a catheter and which enables only a very small quantity of drug to be delivered from the distal tip of the catheter to the treatment site. 
     Rather, conventional transluminal drug delivery catheters require a proximal infusion device which is connected to a proximal end of the infusion catheter and which is used to pressurize a fluid or infusate which contains the drug to be delivered. The catheter is filled with the infusate and the drug is administered at the distal tip of the infusion catheter (upon pressurization of the infusate) after the catheter is inserted and properly positioned. While the internal volume of such infusion catheters is typically small, it is still much too large to make drug delivery with extremely expensive drugs practical. 
     SUMMARY OF THE INVENTION 
     The present invention is drawn to the delivery of a low volume bolus of drug or other treatment material to the myocardium, a vessel, or any other organ or area for which transluminal access is desirable. For example, anti-arrhythmia drugs may be injected into the myocardium using the present invention for electrophysiological therapy. Also, growth factors and other gene therapy substances can be injected into the myocardium for myocardial revascularization. 
     The catheter system includes a catheter having a proximal end, a distal end, and a lumen extending therein. An elongate member slidably disposed in the lumen has a distal end located proximate the distal end of the catheter. An administering tip is disposed at the distal end of the catheter and is configured to express a bolus of liquid in response to positive pressure in a distal portion of the lumen created by movement of the elongate member distally in the lumen. 
     The present invention also includes a method of administering a liquid to a treatment site. A catheter, having a proximal end, a distal end and a lumen extending therein, as well as an elongate member, slidably disposed in the lumen, are provided. The distal end of the catheter is transluminally positioned proximate the treatment site. The catheter is charged by placing a bolus of the liquid in a distal end of the lumen between a distal tip of the catheter and a distal end of the elongate member. The elongate member is then moved distally within the lumen to express the bolus from the distal end of the catheter. 
     Also, the present device should not be limited to implementation using only conventional catheters per se, but also contemplates any steerably, maneuverable syringe structure. Thus, the term catheter should be construed to include both conventional catheters and elongate, maneuverable syringe barrel structures suitable for maneuvering, manipulation, tracking and steering within a vessel. 
     The catheter system can be navigated through several lumens and cavities within the body. Intravascular access by the femoral, brachial and radial arteries is contemplated for accessing target sites within the heart or peripheral vasculature. Alternatively, the catheter may be navigated into the ventricles of the heart by way of the aorta for direct treatment of the heart muscle (myocardium). Yet another alternative for accessing the heart chamber is via the vena cava. Lastly, nonvascular ducts or lumens within the body can be accessed for drug delivery such as for cancer treatment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side sectional view of a catheter system in accordance with one preferred embodiment of the present invention. 
     FIG. 1A illustrates an embodiment of a catheter system of the present invention including a guidewire lumen having a guidewire extending therethrough. 
     FIG. 2 is an enlarged side sectional view of second embodiment of a distal tip of the catheter system in accordance with the present invention. 
     FIG. 3 is an enlarged view of the distal end of a catheter system in accordance with another preferred embodiment of the present invention. 
     FIG. 4 is an enlarged side sectional view of another embodiment of a distal tip of the catheter system in accordance with the present invention. 
     FIG. 5 is an enlarged side sectional view of another embodiment of a distal tip of the catheter system in accordance with the present invention. 
     FIG. 6 is an enlarged side sectional view of another embodiment of a distal tip of the catheter system in accordance with the present invention. 
     FIG. 7 is an enlarged side sectional view of another embodiment of a distal tip of the catheter system in accordance with the present invention. 
     FIG. 8 is a side sectional view of another embodiment of a catheter system in accordance with the present invention. 
     FIG. 9 is a side sectional view of the catheter system of FIG. 8, with a modified liquid reservoir configuration. 
     FIG. 10 is a side sectional view of a catheter system in accordance with one aspect of the present invention, deploying a two piston arrangement. 
     FIG. 11 is a side sectional view of a catheter system in accordance with one aspect of the present invention utilizing a bifurcated piston configuration. 
     FIG. 12 is a side sectional view of a catheter system in accordance with one aspect of the present invention utilizing a valve and engageable valve seat configuration. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a side sectional view of a catheter system  10  in accordance with one preferred embodiment of the present invention. Catheter system  10  includes catheter  12  having a distal end  14  and a proximal end  16  and a lumen  18  running therethrough. In the embodiment shown in FIG. 1, distal end  14  is simply an open end providing distal opening  20 , and proximal end  16  is coupled to proximal manifold  22  in any known conventional manner. 
     Manifold  22  preferably has a lumen  24  extending therethrough which is coaxial with lumen  18 . Lumen  24  is also preferably in fluid communication with lumen  18 . 
     System  10  also preferably includes piston rod  26 . Piston rod  26  is preferably an elongate member which extends from a proximal end  28  (which preferably extends to a region proximal of manifold  22 ) to a distal end  30  which is preferably proximate distal end  14  of catheter  12 . Piston rod  26  preferably has an outer diameter which is just smaller than the inner diameter of lumen  18 . Also, piston rod  26  is preferably slidably disposed within lumen  18  such that piston rod  26  can slide in a direction generally parallel to the longitudinal axis of catheter  18 , in the direction indicated by arrow  32 . 
     Piston rod  26  is supported for reciprocal movement within lumen  18  by virtue of its outer dimensions relative to the inner dimensions of lumen  18 , and also be seal arrangement  34 . Seal arrangement  34  is preferably an o-ring type seal which fluidically seals the interior of lumen  18  from the exterior of system  10  through the proximal end of manifold  22 . Thus, seal arrangement  34  preferably includes an o-ring  36  which is disposed within a generally annular depression or recess  38  formed in lumen  24  of manifold  22 . O-ring  36  is preferably formed of a conventional sealing material, such as silicon rubber, and is secured in annular recess  38  utilizing a suitable adhesive. 
     The distal end  30  of rod  26 , when positioned as shown in FIG. 1, preferably cooperates with the inner periphery of the distal end  14  of catheter  12  to form a bolus chamber  37  for containing a bolus of treatment material. The treatment material contained in chamber  37  can be a drug, growth factors, gene therapy materials, radioactive fluid for restenosis or cancer treatment, clot dissolution agent, or any other desired fluid or liquid material. Also, the material can be injected by high pressure, at high velocity, to mechanically break up clots. As described later in the specification, material delivered by system  10  is administered to a desired site in the body by reciprocation of rod  26  in lumen  18 . 
     The proximal end  28  of piston rod  26  is preferably formed in any suitable manner which allows the user to easily grasp and reciprocate rod  26  within lumen  18 . For example, in the above-identified patent applications which are hereby fully incorporated by reference, a number of different proximal grasping and manipulating members are disclosed. In one arrangement, a threadable connection is provided between proximal end  28  of rod  26  and manifold  22 . In this way, the user can rotate rod  26  to cause either proximal or distal reciprocal movement within lumen  18 . In another preferred embodiment, a release mechanism is provided such that the threadable engagement between rod  26  and manifold  22  can be disengaged to simply push or pull rod  26  for quicker longitudinal movement of rod  26 . Then, for finer adjustment of rod  26 , the threaded engagement is re-engaged and rod  26  is rotated to accomplish longitudinal movement. Further, in the references which are incorporated herein, various grasping members are provided to facilitate grasping and manipulation of rod  26  by the user. Also, electromechanical (e.g., solenoid) actuation of rod  26  can also be used. 
     In any case, in a preferred embodiment, catheter  12  is preferably formed of a suitable material to track through desired vasculature and to access a treatment site in the body. Therefore, in operation, prior to being inserted in the vasculature, catheter  12  is preferably filled with a solution, such as saline, such that all areas between rod  26  and the inner wall of lumen  18  are filled with the liquid solution to eliminate any dead space in lumen  18 . A therapeutic drug or other fluid material is then loaded into the distal end  14  of catheter  18 . This may be done, for example, by moving rod  26  to a position in which its distal end  30  is approximately coterminous with the opening  20  in lumen  18  of catheter  12 . Then, distal end  14  of catheter  12  is placed in the liquid solution to be introduced into the vasculature, and rod  26  is withdrawn a desired distance proximally. Withdrawing rod  26  proximally creates a vacuum in chamber  37  of catheter  12  and thus draws some of the liquid solution to be introduced into chamber  37  of catheter  12 . In one preferred embodiment, visual indicia are provided at the proximal end  28  of rod  26  to indicate to the user the total volume of liquid solution which has been drawn into the distal end  14  of catheter  12  based on proximal withdrawal of rod  26 . 
     After catheter  12  has been charged with the treatment solution, distal end  14  of catheter  12  is advanced through the vasculature and positioned proximate a desired treatment site. This can be accomplished in any number of known manners. For example, the distal tip  14  of catheter  12  can be provided as a cutting tip which can be used to pierce the skin and enter the desired vessel. Further, a separate cutting device can be provided which is used in conjunction with (e.g., over the top of) catheter  12  to introduce catheter  12  into the desired vessel. Still further, conventional guidewire or guide catheter assemblies can be used in conjunction with catheter  12  to guide catheter  12  to a desired location in the vasculature. Use of a guidewire with catheter  12  is preferably accomplished by either providing a separate lumen in catheter  12 , separate from lumen  18 , over which catheter  12  can track the guidewire. FIG. 1A illustrates a catheter  12 A including a separate guidewire lumen  18 - 1  having a guidewire  18 - 2  inserted therethrough to track the catheter from a percutaneous insertion position to a treatment site. Alternatively, catheter  12  can be formed as a single-operator-exchange catheter which includes a distal guidewire tube for tracking over the guidewire. Such arrangements are more fully discussed in the above-referenced U.S. patent applications. 
     In any case, distal end  14  of catheter  12  is advanced under suitable visualization, or according to other positioning techniques, until it resides proximate the site to be treated. Once appropriately positioned, the user advances rod  26  distally such that the distal end  30  of rod  26  creates a positive pressure within chamber  37  of lumen  18  at the distal end  14  of catheter  12 . This positive pressure forces the liquid treatment material out the distal opening  20  in catheter  12  so that it is administered at the desired. 
     In a preferred embodiment, the volume of the chamber  37 , which is defined by the interior periphery of catheter  12  and the distal tip of rod  26 , is preferably less than or equal to approximately 1 ml. Thus, it can be seen that the present invention can be used to directly administer a very low volume bolus of drug or other therapeutic material directly to a desired treatment site within the body, using a transluminal technique. 
     The specific materials used in implementing catheter system  10  can be any suitable, and commercially available materials. For example, manifold  22  is preferably made of an injection molded polycarbonate. Recess  38  within which o-ring  36  resides preferably has approximately a 0.123 inch diameter recess formed in manifold  22 , and the inner diameter of lumen  24  in manifold  22  is preferably approximately 0.042 inches. Catheter  12  can be formed of several sections, or only a single section. Catheter  12  can also be made of any suitable materials, depending on the performance characteristics desired. For example, catheter  12  can be made of an extruded polymer tube, stainless steel hypotube, or a composite material such as stainless steel braid encased in polyimide. To impart different characteristics along its length, catheter  12  may incorporate changes in diameter or combine different constructions. For example, catheter  12  may have a composite proximal section combined with a polymer distal section. Other suitable configurations can be used as well. 
     Rod  26  is preferably made of a stainless steel wire surrounded by a Kynar™ tube. The stainless steel wire preferably has a diameter of approximately 0.019 inches and a length of about 50 inches. The tube surrounding the wire preferably has an outside diameter of approximately 0.038 inches and an inside diameter of 0.020 inches. When fully actuated in the distal direction, rod  26  preferably extends such that its distal end  30  is co-terminus with the distal end  14  in catheter  12 . Positive stops (not shown) can optionally be provided at the distal end  14  of catheter  12  to limit the distal movement of rod  26 . 
     Generally, connections between the various polymer components may be made utilizing suitable grade medical adhesives or thermal bonds which are well known to those skilled in the art. Connections between metallic components are preferably made, for example, by utilizing solder, by brazing, welding, or other suitable techniques. 
     FIG. 2 is an enlarged view of a distal end portion  14  of catheter  12 . Some items shown in FIG. 2 are similar to those shown in FIG. 1, and are correspondingly numbered. However, FIG. 2 illustrates that, rather than rod  26  simply having distal end  30 , a plunger  40  is coupled to distal end  30  of rod  26 . Plunger  24  has an outer diameter which is approximately the same as, or just smaller than, the inner diameter of lumen  18 . Thus, when rod  26  is actuated in the distal direction, plunger  40  and rod  26  act much like a conventional syringe in that the distal chamber  37  defined by the distal end  14  of catheter  12  and plunger  40 , is pressurized. This forces the bolus of treatment material out through the distal opening  20  in catheter  12 . However, since plunger  40  is provided, the outer periphery of the remainder of actuating rod  26  need not be approximately the same as, or just smaller than, the interior periphery of lumen  18 . Instead, it can be much smaller. This significantly reduces the frictional forces acting on rod  26  as it is reciprocated within lumen  18 . It should be noted that plunger  40  can be a separate member attached to the distal end  30  of rod  26 , or it can be formed integrally with rod  26  simply by broadening out the distal end  30  of rod  26 . 
     FIG. 3 is another enlarged view of the distal end of rod  26 . Some items are similar to those shown in FIG. 2, and are similarly numbered. However, rather than having simply plunger  40 , the embodiment shown in FIG. 3 includes plunger head  42 . Plunger head  42  includes a pair of discs  44  and  46  which are mounted about the outer periphery of the distal end  30  of rod  26 . The discs  44  and  46  are preferably separated by an o-ring  48  formed of silicone or other suitable material and sized to fluidically seal lumen  18 . Discs  44  and  46  are also preferably formed of silicon rubber material, or other suitable material, or can be formed integrally with rod  26 . 
     FIG. 4 is an enlarged side sectional view of the distal end  14  of catheter  12  in accordance with another aspect of the present invention. Some items are similar to those shown in FIG.  2  and are correspondingly numbered. However, rather than simply having a distal opening  20  in the distal end  14  of catheter  12 , FIG. 4 illustrates that a separable seal  50  is provided in distal end  14 . Separable seal  50  preferably includes a rubber or polymer material inserted into the distal end  14  of catheter  12  and connected thereto with a suitable adhesive. 
     Separable seal  50  preferably includes a seam  52  therein. Seam  52  is simply formed by the abutment of the surfaces of seal  50  against one another, but those portions are not adhesively or otherwise sealed to one another (other than through friction). This arrangement allows the introduction of a conventional, small diameter, needle which is attached to a syringe containing the treatment solution into the distal end  14  (and hence chamber  37 ) of catheter  12 , and through seam  52 . Thus, the treatment solution can be injected into chamber  37  of catheter  12 , as plunger  40  is withdrawn in the proximal direction to draw the treatment solution therein. 
     Once the distal end  14  of catheter  12  is placed at the treatment site in the vasculature, distal actuation of rod  26  causes plunger  40  to create a pressure behind seal  50  causing seal  50  to separate at seam  52  and thus release the treatment solution at the desired location. In another preferred embodiment, seal  50  is a rolling diaphragm type of seal, or another suitable type of seal configuration. 
     FIG. 5 is an enlarged side sectional view of distal end  14  of catheter  12  in accordance with another aspect of the present invention. Similar items are similarly numbered to those shown in previous figures. However, FIG. 5 illustrates that the distal tip of catheter  12  is provided with a needle having a plurality of apertures  54  therein. Apertures  54  allow the treatment solution  37  to be withdrawn into the distal end  14  of catheter  12 , and to be forced out through the distal end thereof. 
     FIG. 6 illustrates yet another embodiment in accordance with the present invention. FIG. 6 is similar to FIG. 5 except that, rather than having uniformly spaced apertures  54  at the distal tip of catheter  12 , the distal tip or nozzle region is provided with side ports  56  which allow the treatment solution in chamber  37  to be directionally administered in the direction in which side ports  56  are disposed. 
     FIG. 7 illustrates another preferred embodiment in accordance with the present invention. Similar items are similarly numbered to those shown in previous figures. However, the distal end of catheter  12 , rather than being provided as a solid member with apertures therein, is provided as a porous needle portion  58 . Porous needle portion  58  can be provided as a microporous membrane, as a selectively porous membrane, or as any other suitable porous or capillary type material, suitable for the introduction of treatment solution from chamber  37  to the treatment site. 
     FIG. 8 is a side sectional view of a catheter system  60  in accordance with another preferred embodiment of the present invention. Some items are similar to those shown in FIGS. 1-7, and are similarly numbered. However, catheter  12  is also provided with a treatment fluid reservoir  62  defined by wall  64  which is preferably arranged about an exterior portion of catheter  12 . Reservoir  62  extends from a distal end  66  which is arranged just proximal of administration tip (or nozzle)  68 , to a proximal end  70  which is provided with a suitable fitting for receiving the treatment solution. 
     In operation, the treatment solution is preferably injected, using a standard syringe, through proximal portion  70  of reservoir  62 . A flapper valve  72  is preferably provided at distal end  66  of reservoir  62  to fluidically separate lumen  18  in catheter  12  from reservoir  62 . In the preferred embodiment, flapper valve  72  is arranged such that it pivots generally in a direction indicated by arrow  74  and is hingedly attached by hinge  76  to the wall of catheter  12 . Flapper valve  72  has a distal end  78  which engages a positive stop  80  on the inside of lumen  18  of catheter  12 . 
     Therefore, when plunger  40  is withdrawn proximally, this creates a vacuum or low pressure area within chamber  37 , relative to reservoir  62 . This causes flapper valve  72  to lift upwardly to allow fluid to escape from reservoir  62  into chamber  37 . Then, when plunger  40  is advanced distally, this creates a high pressure region in lumen  18  relative to reservoir  62  so that flapper valve  72  closes and the distal end  78  of flapper valve  72  abuts positive stop  80 . 
     As plunger  40  continues to be advanced distally, the treatment solution in chamber  37  is passed through administering tip  68  to the desired site. In the preferred embodiment, administering tip  68  is provided with very small apertures, or pores, or valved openings, such that a greater pressure differential is required between the interior lumen  18  and the exterior of catheter  12  to cause liquid material to pass through administering tip  68  than is required to lift flapper valve  72 . Therefore, as plunger  40  is withdrawn proximally, flapper valve  72  opens to allow the treatment material in chamber  62  to enter lumen  18 , but no fluid, or very little fluid, is drawn into lumen  18  from outside catheter  12 . Then, as plunger  40  is advanced distally, flapper valve  72  closes and a great enough pressure is built within chamber  37  to cause the treatment material to pass through administering tip  68  to the desired position. 
     It will thus be appreciated that the embodiment disclosed in FIG. 8 allows the user to position distal tip  14  of catheter  12  at the desired location within the body before chamber  37  is charged with the bolus of treatment material to be injected at the treatment site. 
     FIG. 9 shows another embodiment of the distal end  14  of catheter  12  in catheter system  60 . Similar items are similarly numbered to those shown in FIG.  8 . However, rather than providing reservoir  62  extending all the way from distal end  66  thereof to proximal end  70  thereof, reservoir  62  is maintained only at a distal portion of catheter  12 . Reservoir  62  is also provided with a suitable introduction valve  82  which can preferably be used in conjunction with a conventional syringe, to introduce the bolus of treatment material into reservoir  62 . By not requiring reservoir  62  to extend all the way to the proximal end  70 , the internal volume of reservoir  62  can be kept very small. This facilitates utilizing only a needed volume of treatment material. No extra material is required to fill the internal volume of reservoir  62 , since that volume is so small. 
     FIG. 10 shows another preferred embodiment of the catheter system  84  in accordance with the present invention. Catheter system  84  is similar to catheter system  60  shown in FIG. 8, and similar items are similarly numbered. However, catheter system  84  includes a modified form of treatment reservoir  62 . Rather than terminating in its proximal area at proximal end  70 , the proximal end of reservoir  62  in catheter system  84  extends all the way through proximal manifold  22  in the same fashion as lumen  24 . Also, reservoir  62  is provided with a reciprocally mounted rod  86  and plunger  88 . Further, rod  86  is sealably mounted within manifold  22  by seal configuration  90  which is similar to seal configuration  34  discussed with respect to FIG.  1 . The proximal ends of rods  26  and  86  can optionally be either connected to one another, or separate from one another for separate actuation by the user. 
     In any case, in order to introduce the bolus of treatment material into reservoir  62 , rod  86  and plunger  88  are advanced to the distal-most actuation point in which they abut a second flapper valve arrangement  92 . Flapper valve  92  is biased to normally close an aperture  94  against an inner portion  96  of the distal end of reservoir  62 . Then, the distal tip  14  of catheter  12  and reservoir  62  are placed in the drug solution to be administered. Rod  86  and plunger  88  are then withdrawn distally a desired amount such that flapper valve  92  opens to allow the fluid to be administered to enter reservoir  62  through aperture  94 . When the distal tip  14  of catheter  12  is appropriately positioned in the vasculature, rod  86  and plunger  88  are then advanced distally to charge catheter  12  by introducing the material to be administered from reservoir  62 , through flapper valve arrangement  72 , and into chamber  37  in catheter  12 . Once charged, catheter  12  is ready to administer the treatment solution. Thus, the user advances rod  26  and plunger  40  such that the bolus of treatment solution is injected from chamber  37  through the administering tip of catheter  12  to the desired site. 
     FIG. 11 shows another catheter system  98  in accordance with another preferred embodiment of the present invention. Similar items are similarly numbered to those shown in previous figures. Catheter system  98  is similar to catheter system  84  and similar items are correspondingly numbered. However, rather than providing two rods  26  and  86 , as in FIG. 10, catheter system  98  includes bifurcated rod  100 . Bifurcated rod  100  includes first leg portion  102  which is connected to plunger  40  and which resides within lumen  18  of catheter  12 . Bifurcated rod  100  also includes second leg portion  104  which is connected to plunger  88  and lies in reservoir  62 . Catheter system  98  shown in FIG. 11 is also preferably provided with a valve arrangement similar to valve arrangement  82  shown in FIG. 9 by which the treatment material is inserted into reservoir  62 . 
     In the embodiment shown in FIG. 11, the treatment material is simultaneously introduced from reservoir  62  into chamber  37  distal of plunger  40 , and it the bolus of material is injected at the desired site, as the user advances bifurcated rod  100  distally. Plunger  82  causes high pressure in reservoir  62  to move the bolus of treatment material from reservoir  62  into chamber  37  distal of plunger  40 . At the same time, plunger  40  causes high pressure to be developed in chamber  37  such that the bolus of material is advanced through the administering tip to the desired site. 
     FIG. 12 is similar to FIGS. 10 and 11, and similar items are similarly numbered. However, reservoir  62  is provided with different valve arrangements. Rather than flapper valve  72 , a simple aperture  106  is provided between reservoir  62  and lumen  18 . A plunger  108  is sized to completely cover aperture  106  when it is advanced to its distal most position (shown in phantom in FIG.  12 ). Thus, the operator can advance plunger  108  within reservoir  62  to charge lumen  18  with a bolus of material. The operator can, either simultaneously or separately, advance plunger  40  to administer the material through the tip of the catheter, once chamber  37  has been charged with the bolus. 
     Thus, it can be seen that the present invention provides a number of advantages over prior art infusion techniques. The present invention can be utilized to transluminally access a site to be treated within the body. The present invention can also be utilized to administer a therapeutic solution, or any desired solution, at that site. Further, the present invention can be utilized to administer only a very small volume bolus of material, preferably less than 1 milliliter at the site. This allows the pragmatic administration of even very expensive drugs in an efficient and accurate manner. 
     It should also be noted, of course, that the distal tip of the catheter can be arranged to provide any sort of nozzle configuration. The distal tip can be valved, it can have apertures uniformly distributed thereabout, it can have apertures directionally distributed thereabout, and it can have apertures which provide desired injection or dispersion characteristics. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.