Component mixing catheter

A component mixing catheter (2) includes a catheter shaft (4) having proximal and distal ends (6, 8) and defining first and second lumens (10, 12). The catheter shaft has an exterior opening (16) at or near its distal end (8) which is fluidly coupled to the first lumen. One or more connecting passages (14) fluidly connect the first and second lumens at a position (30) spaced apart from the exterior opening. The second component passes through the connecting passage and mixes with the first component at a mixing region (25) within the first lumen just prior to exiting the catheter at the exterior opening for maximum therapeutic effect or diagnostic accuracy.

BACKGROUND OF THE INVENTION 
Catheters are used for many different medical reasons. One use is to 
deliver drugs or other substances to a target site within the body in a 
region accessible by the tip of a catheter. However, some compounds are 
not as effective when premixed. For example, they may have a short half 
life or they may need to be mixed at the target site for other reasons to 
achieve maximum therapeutic effect or more accurate diagnostic results. 
Conventional methods for delivering two components via catheter include the 
following. One way is to infuse one substance through an outer or guiding 
catheter and the other through an inner or microcatheter, the distal end 
of the inner catheter extending out past the distal end of the guiding 
catheter. Another method is to infuse the two components alternately 
through the same microcatheter. Finally, two microcatheters could be 
placed side by side and directed to the target site. All of these 
solutions have been proven less than totally satisfying. 
SUMMARY OF THE INVENTION 
The present invention is directed to a catheter and a method for delivering 
a substance to a target site using the catheter by which two or more 
components constituting the substance are mixed at the distal end of the 
catheter just prior to being discharged from an exterior opening at the 
distal end of the catheter to the target site. 
The catheter includes a catheter shaft having proximal and distal ends and 
define first and second lumens. The catheter shaft has an exterior opening 
at or near its distal end which is fluidly coupled to the first lumen. One 
or more connecting passageways fluidly connect the first and second lumens 
at one or more positions spaced apart from the exterior opening. 
Therefore, flowing first and second components through the first and 
second lumens causes the components to combine as the second component 
passes through the passageway to mix with the first component at a mixing 
region within the first lumen prior to exiting the catheter at the 
exterior opening. This way, a substance to be delivered to the target site 
within a patient is mixed just prior to being applied to the target site 
for maximum therapeutic effect or diagnostic accuracy. 
A primary advantage of the invention is its flexibility. Two or more 
individual components can be mixed just prior to delivery to the target 
site through the exterior opening at the distal end of the catheter. The 
time, amount and turbulence of the mixing can be varied by changing the 
size and placement of the connecting passages, the distance from the 
connecting passages to the exterior opening, the placement and shape of 
the exterior opening, the use of turbulence-inducing elements, and other 
such techniques. Also, when three or more components are mixed together, 
mixing can be effected serially or simultaneously, or a combination of the 
two. 
With the present invention, maximum therapeutic effect or diagnostic 
accuracy can be achieved by mixing the components of the substance being 
applied to the target area just prior to their application. For example, 
plasmine can be created using plasminogen and TPA as the first and second 
components mixed just before delivery of the plasmine to the target site. 
This minimizes the time between mixing and delivery which is so important 
for substances, such as plasmine, which have a short half-life. Other 
components may have a complementary physiologic action. Examples of this 
include a drug that disrupts the blood brain barrier, such as RMP-7, a 
chemotherapeutic agent, such as carboplatin, or a two-part epoxy for 
embolic therapy. In such cases, it is necessary or at least desirable to 
mix the components only moments before delivery to the target site. 
Other features and advantages of the invention will appear from the 
following description in which the preferred embodiments have been set 
forth in detail in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 and 2 illustrate a mixing catheter 2 including a dual lumen 
catheter shaft 4 having proximal and distal ends 6 and 8 respectively and 
a length of about 100 to 150 cm (39 to 59 inches), the length, of course, 
being determined by the patient and the procedure. When mixing catheter 2 
is used as a microcatheter for use in procedures such as thrombolysis, 
chemotherapy or embolic therapy, catheter shaft 4 will have an outside 
diameter of about 2 to 5 French (0.67 to 1.67 mm). 
Catheter shaft 4 is a dual lumen, coaxial catheter shaft including a first, 
inner lumen 10 and a second, external lumen 12. External lumen 12 
terminates about 1-10 cm from distal end 8. Lumens 10, 12 are fluidly 
coupled through a number of connecting passages 14. This arrangement 
permits the two components passing through first and second lumens 10, 12 
to mix within first lumen 10 prior to exiting an exterior opening 16 
formed at distal end 8. A portion of the length of first lumen 10 between 
connecting passages 14 and external opening 16 is defined by a coil 18. 
Coil 18 is made of platinum or other radiopaque material and is used to 
give the tip radiopacity during fluoroscopy. 
Proximal end 6 of catheter 4 is connected to a proximal end connector 20 
having a main or coaxial arm 22 through which a guidewire 23 can be 
inserted through first lumen 10 and then, after guidewire 23 has been 
withdrawn, coupled to a source of liquid or other flowable material. 
Connector 20 also includes a side arm 24 fluidly coupled to second lumen 
12 for the passage of liquid or other flowable material through the second 
lumen, through connecting passages 14 and into first lumen for mixing in a 
mixing region 25 of first lumen 10 with the first component. 
In use, once the target site is identified, the tip 26 of catheter shaft 4 
is directed to the target site using guidewire 23 in a conventional 
manner. Once properly located at the target site, guidewire 23 can be 
removed from within first lumen 10 and first and second components can be 
directed through and second lumens 10, 12 for mixing within mixing region 
25 of first lumen 10. Use of mixing catheter 2 permits two different 
components to be mixed just prior to delivery to the target site through 
external opening 16 for maximum therapeutic effect in the case of, for 
example, treatment of thrombosis using plasminogen or TPA or treatment of 
tumors using RMP-7 or carboplatin. 
FIGS. 3 and 3A illustrate an alternative embodiment of the invention in 
which first and second coaxial lumens 10, 12 are replaced by first and 
second side-by-side lumens 10A, 12A, both of which terminate at a position 
spaced apart from external opening 16A at distal end 8A. 
FIGS. 4 and 4A illustrate a three-lumen catheter 4B including first and 
second lumens 10B, 12B and a third lumen 28. Liquid or other flowable 
material is pumped through lumens 10B, 12B which terminate at a position 
30B adjacent distal end 8. However, exterior opening 16B is formed through 
an external wall defining third lumen 28 spaced apart proximally from 
position 30B. As in the embodiments of Figs. 2 and 3, the first and second 
components both have an opportunity to mix within mixing region 25B just 
prior to exiting catheter 4B through external opening 16B. 
FIGS. 5 and 5A illustrate a three-lumen catheter 4C similar to catheter 4B 
of FIG. 4 but adapted to have three different components pumped through 
lumens 10C, 12C and 28C. External opening 16C is at distal end 8 while 
passages 14C coupling first and second lumens 10C, 12C is spaced apart 
proximally from distal end 8 and passages 14C coupling second and third 
lumens 12C, 28C is spaced apart proximally from the passages 14C coupling 
first and second lumens 10C, 12C. This permits the sequential mixing of 
three different components by the staggered placement of connecting 
passages 14C. If desired, other sizing and positioning of connecting 
passages 14C could be used according to the mixing sequence and amounts 
desired. 
Modification and variation can be made to the disclosed embodiments without 
departing from the subject of the invention as defined in the following 
claims. For example, more than one exterior opening 16 can be used. 
Turbulence-inducing structure can be used in mixing region 25.