INTRAVASCULAR CATHETER HAVING AN ADJUSTABLE LENGTH INFUSION SECTION TO DELIVERY THERAPEUTIC FLUID
BACKGROUND OF THE INVENTION
This invention generally relates to a vascular catheter which delivers therapeutic fluid to a desired location within a patient's vasculature.
Therapeutic fluids such as those containing uroki- 10 nase, streptokinase, tissue plasminogen activator (TPA) have been found effective in many instances in the treatment of vascular thrombosis. The systemic administration of such therapeutic agents is not always desirable because the entire body of the patient must be medi- 15 cated in order to treat small vascular sites. Delivery of therapeutic fluids through vascular catheters directly to a desired treatment site is usually more effective and, moreover, with direct delivery higher concentrations of the therapeutic agent may be used in the treating solu- 20 tion.
In the direct delivery of therapeutic fluid to a thrombotic region in the patient's vasculature, it is highly desirable to limit the application of the therapeutic fluid only to the treatment site to limit the amount of thera- 25 peutic agent used (which can be very expensive) and to avoid over medicating the patient. Frequently, there are multiple treatment sites of various lengths which require the use of multiple catheters having at the distal end thereof drug delivery sections of various lengths to 30 effectively deliver the treatment fluid only to the treatment site. In these instances, either a separate catheter must be used at each treatment site, which increases the time and the inconvenience of the procedure, or inefficient application of the treatment fluid must be ac- 35 cepted.
What has been needed is a catheter delivery system which can deliver therapeutic fluids to one or more thrombotic sites with means to adjust the effective length of drug delivery section of the catheter body, 40 particularly after the catheter has been inserted into the patient's blood vessels. The present invention provides a catheter which satisfies this need.
SUMMARY OF THE INVENTION 45
The present invention is directed to a catheter for the intravascular delivery of drugs or therapeutic agents wherein the effective length of the catheter section which delivers the treatment fluid can be adjusted after the catheter is inserted into the patient's vascular sys- 50 tern.
The catheter assembly in accordance with the invention has an elongated catheter body with an inner lumen which extends from the proximal end thereof to an infusion section in the distal portion thereof having 55 passageways in the wall thereof for discharging fluid from the lumen. Longitudinally movable means such as a sheath is provided to adjust the effective length of the infusion section.
In one presently preferred embodiment, a snugly 60 fitting sheath is slidably mounted onto the exterior of the catheter body so that longitudinal or axial movement of the sheath with respect to the catheter body blocks or unblocks a greater or lesser number of fluid flow passageways in the wall of the infusion section. In 65 another presently preferred embodiment, a tubular sheath snugly fits within the interior of the catheter body and is adapted to be slidable therein so that a
greater or lesser number of fluid flow passageways passing through the wall of the infusion section are blocked or unblocked to thereby control the effective length of the infusion section.
The elongated catheter body generally has an outer tubular element and an inner tubular element coaxially disposed within the outer tubular element with the distal ends of these tubular members sealingly bonded together to prevent loss of therapeutic fluids therefrom. An annular lumen which is defined between the inner and outer tubular element directs therapeutic fluids from an adapter provided on the proximal end of the catheter body to the distal portion thereof having the infusion section. The length of the infusion section in the distal portion of the catheter which is effective in infusing therapeutic fluid may be adjusted prior to or after inserting the catheter into a patient's vascular system. These adjustments are performed from the proximal end of the catheter which normally extends out of the patient during the vascular procedure.
These and other advantages of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view partially in section of a drug delivery catheter embodying features of the invention;
FIG. 2 is an enlaged view of the distal end of the catheter shown in FIG. 1 partially in section;
FIG. 3 is a transverse cross-sectional view of the catheter shown in FIG. 1 taken along the lines 2-2;
FIG. 4 is an elevational view of another drug delivery catheter embodying features of the invention;
FIG. 5 is an enlarged sectional view of the distal end of the catheter shown in FIG. 4 taken along the lines 5—5 shown in FIG. 4
FIG. 6 is a cross-sectional view of the drug delivery catheter shown in FIG. 4 taken along the lines 6—6; and
FIG. 7 is a partial longitudinal view in section of a distal section of a drug delivery system similar to that shown in FIG. 1 with a porous section to discharge fluid through the wall of the catheter.
DETAILED DESCRIPTION OF THE
Reference is made to FIGS. 1-3 which illustrate a catheter assembly for the intravascular delivery of therapeutic fluids. The catheter assembly 10 generally includes an elongated catheter body 11 having an outer tubular element 12 and an inner tubular element 13 concentrically disposed therein, an adapter 14 on the proximal end of the catheter body, and an elongated sheath 15 mounted for slidable movement on the exterior of the catheter body 11.
The inner and outer tubular elements 13 and 12, respectively, define therebetween an annular lumen 16 for directing treatment fluid to the infusion section 17 in the distal portion of the catheter body 11 wherein fluid flow passageways 18 provided in the wall 19 of the outer tubular element 12. The distal ends of the inner and outer tubular elements 13 and 12 are sealingly bonded such as by adhesive, heat shrinking, or other suitable means to prevent loss of the treatment fluid therefrom. The inner tubular element 13 is provided with an inner lumen 20 adapted to receive a guidewire (not shown)