Catheter exchange system

A dilation catheter of the invention is formed of a flexible tube having distal and proximal ends, and a balloon attached to the distal end of the tube. The catheter includes a first opening formed in the tube to communicate with the balloon, and a second opening formed in the tube near the proximal end of the balloon. A partition is located inside the tube to communicate the proximal end of the tube with the first opening. Thus, inflation and deflation of the balloon attached to the tube can be controlled by fluid applied through the tube. A guide wire extends through the tube between the distal end and the second opening.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT 
The present invention relates to angioplasty apparatus for providing a 
dilation catheter to facilitate a quick exchange of the dilation catheter. 
The dilation catheter is introduced into a body of a patient to enlarge 
constrictions in blood vessels and other body cavities. In one of 
conventional dilation catheters, an inner lumen is situated inside an 
outer lumen, and a balloon is attached to the distal end of the outer 
lumen. A guide wire is located inside the inner lumen. 
In this method, firstly, a guide wire is introduced into a desired 
location, and secondly, the inner lumen with the outer lumen over the 
guide wire is pushed over the introduced guide wire to the desired 
location. The inner and outer lumens may be introduced into a blood vessel 
together with the guide wire. 
However, should the need to exchange the introduced catheter, for example 
to change the size of the balloon, the guide wire must be protruded from 
the patient's body by a length greater than the length of the dilation 
catheter. Therefore, an extension wire is attached to the first introduced 
guide wire. When the catheter is changed, the guide wire is held firm in 
location, the dilation catheter in the blood vessel is withdrawn, and the 
new dilation catheter is introduced over the guide wire to complete the 
exchange. The handling of the extended guide wire is very cumbersome 
because of the length of the guide wire. 
In order to solve the above problem, a short inner lumen is attached to a 
long outer lumen to extend from the distal end of the outer lumen. The 
proximal end of the inner lumen is sealingly attached to a side wall of 
the outer lumen near the distal end thereof. An inflatable balloon is 
attached between the distal ends of the inner and outer lumens. The guide 
wire passes through the inner lumen to advance or retract the catheter on 
the guide wire. The outer lumen has a port on the proximal end, and the 
balloon is capable of being inflated or deflated through the outer lumen 
from the proximal end by means of a syringe or other devices. 
In the above improved catheter, since the guide wire passes only through 
the short inner lumen, the catheter can be exchanged easily without using 
the extension guide wire. 
In U.S. Pat. No. 4,762,129, a short tube for guiding the guide wire is 
attached to the distal end of a long tube. A balloon is also attached to 
the distal end of the long tube, and a fluid is introduced into the 
balloon through the long tube. 
Although these improved systems mentioned above may avoid the requirements 
for using the long extended guide wires, the coaxial and dual lumens are 
attached to the proximal end of the balloon, so that the outer diameter 
becomes larger as well as the distal end of the catheter is too stiff to 
follow the bending vessels. Further, in the dual lumen design where the 
short tube is attached to the long tube, the rotation and pushability of 
the dilation catheter are reduced since the inner lumen tracking on the 
guide wire is pushed with the outer lumen in the offset position. 
The same can be said on the coaxial design, since the outer lumen does not 
extend to the distal end of the balloon. Namely, the only common junction 
between the outer and inner lumens is the one where the proximal end of 
the inner lumen is exiting from the outer lumen. 
In the angioplastisy, the above lumens are generally guided by a guide 
catheter, and as the blood vessel becomes a small diameter, the lumens are 
extended from the guide catheter. Thus, the design of the two lumen 
catheters with the guide wire exiting from the guide catheter increases 
the outer diameter of the guide catheter or the total size of the dilation 
catheter to thereby limit the ability of the introduction of two or more 
of the dilation catheters in the same guide catheter of a small size. 
Accordingly, an object of the invention is to provide a dilation catheter 
to obviate the foregoing difficulties. 
Another object of the invention is to provide a dilation catheter as stated 
above, which has a small diameter and can be controlled easily without 
trouble. 
A further object of the invention is to provide a dilation catheter as 
stated above, which can be easily manufactured. 
Further objects and advantages of the invention will be apparent from the 
following description of the invention. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a dilation catheter is formed of 
a flexible tube, and a balloon attached to the distal end of the tube. A 
first opening is formed in the tube to communicate with the balloon, and a 
second opening is formed in the tube near the proximal end of the balloon. 
A partition is located inside the tube to communicate the proximal end of 
the tube with the first opening. Thus, the inflation and deflation of the 
balloon attached to the tube can be controlled by fluid applied through 
the tube. A guide wire for leading the catheter passes through the tube 
between the distal end and the second opening. 
In the invention, the tube constitutes a single lumen to facilitate quick 
exchange capability as! well as to provide a better axial force and torque 
transmission. The use of the partition with the single lumen minimizes the 
over all size or thickness, resulting in a better flexibility and 
transition of force applied to the lumen. As a result, the catheter can be 
lead smoothly to tight lesions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In the typical angioplasty treatment, a guide catheter, not shown in the 
drawing, having a diameter of several millimeters and a length of about 
one meter, is introduced from a patient's right groin throughout the 
length of the artery to the aorta. A guide wire 8 in FIG. 1, which is 
slightly longer than the guide catheter, is introduced through the guide 
catheter and advanced to pass the lesion in the patient's vessel. The 
guide wire 8 is used to track or guide the dilatation catheter. 
The dilation catheter is formed of a single lumen 1, a balloon 2 attached 
to the lumen 1, and a partition 3 situated inside the lumen 1, as shown in 
FIG. 1. The lumen 1 further includes openings 10, 12. The partition 3 
sealingly divides the inside of the lumen 1 into first and second channels 
7, 9. 
The first channel 7 communicates with an interior 4 of the balloon 2 
through the opening 10, while the second channel 9 communicates with the 
opening 12. The first channel 7 is used to inflate and deflate the balloon 
2, and the second channel 9 is used to track the guide wire 8. The channel 
7 is completely sealed from the channel 9 by the partition 3. 
The balloon 2 is formed of an outer envelope and is sealed to the lumen 1 
at a distal end 11 and a proximal end 5 to complete the sealed enclosure. 
The balloon 2 is inflated and deflated through the opening 10 when fluid 
is introduced or withdrawn through the first channel 7 from a port at the 
proximal end of the lumen 1. 
In use, the dilation catheter is assembled with the guide wire 8 such that 
the guide wire 8 passes through the second channel 9 from the opening 6 
and exits at the opening 12. The catheter may be advanced in the vessel of 
the patient by securing the position of the guide wire 8 relative to the 
guide catheter. When the distal end of the lumen 1 is arrived at the 
desired location, fluid is supplied to inflate the balloon 2 for the 
dilation of the lesion. Thereafter, when the catheter is withdrawn, the 
fluid inside the balloon 2 is discharged through the lumen 1. Then, the 
guide wire 8 is held and the single lumen catheter is removed along the 
guide wire 8. 
When the dilation catheter is exchanged while using, e.g. for changing the 
size of the balloon, the guide wire 8 is held in position, and the 
dilation catheter is taken out of the blood vessel along the guide wire 8. 
Then, a different dilation catheter is placed over the guide wire 8, and is 
advanced along the guide wire 8. 
In the invention, since the channel 9 in the lumen 1 is short, the dilation 
catheter can be easily exchanged without using a long guide wire. Also, 
since the size or thickness of the lumen 1 is small, the dilation catheter 
can be advanced to a small blood vessel. 
FIG. 5 shows an alternative embodiment of the dilation catheter of the 
invention, wherein the proximal end of the balloon 2 is attached to the 
lumen I in an offset condition. Thus, it is possible to form a large hole 
10 to thereby easily and quickly inflate and deflate the balloon. 
While the invention has been explained with reference to the specific 
embodiments of the invention, the explanation is illustrative and the 
invention is limited only by the appended claims.