Catheter with lumen occluding means

A catheter for use with the vascular system includes an elongated catheter body which has a side wall defining an interior catheter lumen. A plurality of openings are provided in the side wall at a first distal zone of the catheter body. The openings are adapted for relatively low pressure movement of fluid therethrough. A plurality of normally closed pressure responsive exits are located in a side wall at a second distal zone of the catheter body, the second distal zone being spaced from and positioned proximal of the first distal zone. The pressure responsive exits permit fluid material to exit from the catheter lumen in response to internal fluid pressure which is greater than a predetermined magnitude. An intermediate zone is located between the first and second distal zones. A removable occluding member is adapted to be positioned within the catheter lumen. The occluding member has a sealing element with a collapsed insertion state and an expanded sealing state. When the sealing element is in the sealing state and positioned in the intermediate zone, it can be expanded to contact the inside surface of the side walls of the lumen in order to seal off fluid communications between the first and second distal zones. When the occluding member is in the sealed position, enzymatic fluid material is inserted through the lumen at a pressure greater than the predetermined magnitude to cause it to pass through the pressure responsive exits in order to contact any fibrin built up along the outside surface of the elongated catheter body radially expanding the catheter body causing the fibrin to loosen, dissolve and dissipate.

FIELD OF THE INVENTION 
The present invention relates generally to the field of catheters for long 
term use in delivering and removing fluid material into or from the 
vascular system, and more particularly, to such a catheter having a means 
for occluding a portion of the catheter to enable pressure responsive 
orifices to open in the catheter body in order to facilitate removal of 
fibrin build up on the outside surface of the catheter when the catheter 
is inside the vasculature. 
BACKGROUND OF THE INVENTION 
Elongated catheters for obtaining access to a vascular system are well 
known in the art and have been used in the medical field for many years. 
Such catheters usually have an elongated body with proximal and distal 
ends. A catheter lumen is formed interiorly of the body. A hole or opening 
is located at the distal end of the elongated body so that fluid material 
can either pass from the catheter lumen through the hole into the vascular 
system or so that fluid from the vascular system may be drawn through the 
distal end hole into the catheter lumen to be withdrawn from the vascular 
system. Fluid material which is intended to be infused into the vascular 
system is introduced into the catheter lumen through its proximal end. 
Pressure responsive exits in the form of slits may be arranged in the side 
wall of the catheter body as a means for infusing fluid which is under a 
desired pressure from the catheter lumen into the vascular system at a 
desired rate and at a desired location. 
Catheters of the foregoing type have been used for a variety of purposes. 
While some applications do not require that the catheter remain in the 
vascular system for any significant length of time, other uses or medical 
procedures, such as dialysis, may require that the catheter remain in the 
vascular system for long periods of time. While the typical catheter in 
use today is made of polymeric material, which is biocompatible, such 
materials are not of natural origin. As a result, the longer a catheter 
remains in the vascular system, the more likely it is that deposits of 
fibrin will form on the outside surface of the catheter body. Over time, 
such deposits will build up, forming a fibrin sheath along the outside 
surface of the catheter. The formation of fibrin build up and the creation 
of such a fibrin sheath on the outside surface of a catheter within a 
vascular system can have serious deleterious effects. Fibrin forms an 
attractive environment for the growth of bacteria. Although small amounts 
of bacteria in a human body may not cause serious problems as the natural 
defenses of the human body can combat the effects of such small amounts of 
bacteria, the presence of a fibrin build up or sheath provides an 
environment where bacteria can accumulate and grow. The growth of bacteria 
at such a site may therefore result in infections. The occurrence of such 
an infection will require a course of anti-biotic treatment and usually 
the removal of the catheter in order to overcome the bacterial infection 
and to allow the patient to recover from its effects. Not only will the 
patient now have to overcome the effects of an infection, but the patient 
is not receiving the benefit of the treatment which required the use of 
the catheter in the first place. 
The build-up of a fibrin sheath on the outside wall of a catheter in a 
vascular system may also cause the partial or complete obstruction of 
holes and openings, such as at the distal end of the catheter, thereby 
ihibiting or preventing the passage of fluid material through the holes 
either into the vascular system or from the vascular system. Thus, when 
attempting to infuse or withdraw fluids into or from the vascular system, 
or during such procedures as dialysis, the catheter will not be able to 
handle the required flow rates. 
Heretofore, the solution to the build up of a fibrin sheath has been to 
replace the catheter with a new one, requiring significant cost and time, 
or to physically remove the fibrin from the outside walls of the catheter 
body while the catheter remains in place within the patient's vascular 
system. The procedure to accomplish this removal of the fibrin sheath 
involves an additional entry into the patient's vascular system so that a 
mechanical device, such as an expanding basket or snare, may be inserted 
into the vascular system and manipulated to the site of the catheter. The 
basket or snare is then used to strip the fibrin build up from the outside 
surface of the catheter, thus freeing up the openings to allow fluid to 
pass through the catheter into or from the vascular system and to 
eliminate an environment that would promote the growth of bacteria. Such a 
procedure for stripping the fibrin material from the outside surface of 
the catheter, however, results in the sudden release and availability of 
large amounts of fibrotic material which may travel through the patient's 
vascular system to the lungs with disastrous results. In addition, the use 
of such mechanical devices as a basket or snare, will cause damage to the 
catheter which could result in its subsequent failure. Such a stripping 
procedure is also expensive. 
OBJECTS OF THE INVENTION 
It is accordingly a principal object of the present invention to provide a 
catheter with the means to facilitate removal of fibrin build up on the 
outside walls of a catheter during extended use in a manner which 
overcomes the foregoing disadvantages. 
A more specific object of the invention is to provide a catheter having an 
elongated catheter body with side walls forming an interior lumen. A 
plurality of openings are formed in the side wall in a first distal zone 
of the catheter body through which fluid at relatively low pressure may 
pass into or from the vascular system. The catheter body is also provided 
with a plurality of normally closed pressure responsive exit slits in the 
side wall at a second distal zone located proximal of the first distal 
zone. Means are provided for sealing the lumen between the exit slits and 
openings so that fibrin treating material, such as an enzyme which can 
solubilize the fibrin, may be supplied through the lumen under elevated 
pressure and thus be caused to exit the pressure responsive slits to 
chemically and mechanically remove the fibrin build up along the catheter 
body. 
Another object of the invention is to provide a catheter which will expand 
when fluid under relatively high pressure is inserted into it, thus 
causing fibrin build-up to break up, and which has pressure responsive 
exit slits through which therapeutic fluid under high pressure will exit 
thus also breaking up a fibrin sheath on the outside surface of the 
catheter body. 
Another object of the present invention is to provide a catheter having an 
elongated body formed by side walls and a lumen interiorly of the side 
walls with openings at one distal zone to allow passage of fluid material 
therethrough at a relatively low pressure, and a second distal zone having 
exit slits through which fluid may pass under relatively high pressure, 
and a means for sealing the interior lumen at a location between the first 
and second distal zones to allow passage of therapeutic or fibrinolytic 
material which will come into contact with in order to dissolve and cause 
removal of the fibrin buildup. 
Yet a further object of the invention is to provide a method for removing 
fibrin build up from the outside surface of a catheter within a vascular 
system, while overcoming the disadvantages of prior techniques, by 
injecting into the catheter an enzymatic material capable of solubilizing 
the fibrin so that it can come in contact with the fibrin in order to 
dissolve it. 
BRIEF DESCRIPTION 
The invention is directed to a catheter for use with the vascular system 
which has an elongated catheter body formed by a side wall defining an 
interior catheter lumen. A plurality of openings are provided in the side 
wall in a first distal zone. These openings are adapted for passage of 
fluid material therethrough at relatively low pressures. A plurality of 
normally closed pressure responsive exit slits are also formed in the side 
wall at a second distal zone, which is spaced from and proximal of the 
first distal zone. Fluid material can pass through the pressure responsive 
exit slits as a result of fluid pressure greater than a predetermined 
level. A removable sealing member having a sealing portion with a 
collapsed insertion state and an expanded sealing state is provided for 
insertion into the lumen. The sealing portion of the removable sealing 
member is positioned to occlude a portion of the lumen to prevent passage 
of fluid material through the openings so that fibrin treating material is 
caused to pass through the exit slits and come in contact with any fibrin 
build up on the outside surface of the catheter in order to solubilize the 
fibrin, thus causing removal of the fibrin material. 
The foregoing and other features of the present invention are more fully 
described with reference to the following drawings annexed hereto.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, and with particular reference to FIG. 1, 
reference numeral 10 denotes an in-dwelling catheter assembly formed by 
two identical catheter bodies 11 which may be used together for an 
application such as dialysis. The cross sectional shape of catheter bodies 
11 may be circular or D-shaped in order to fit together. In such use, one 
of the catheter bodies will be used for withdrawing vascular fluid or 
blood and the other catheter body may be used for infusing treated blood 
or other fluid material into the vascular system The two catheter bodies 
are supported together by a coupling sleeve 13. Each catheter body 11 has 
a side wall 14 forming an interior lumen 12 which extends longitudinally 
through the catheter body terminating at distal end 20. A hole 21 is 
located at the distal end of the catheter body for use in passing fluid 
into the vascular system. Each catheter body 11 has a first distal zone 15 
and a second distal zone 16. Distal zone 16 is spaced from and located 
proximal to the first distal zone 15. The space between the first and 
second distal zones 15 and 16 respectively defines a third distal zone 19. 
Within the first distal zone 15 there are a plurality of openings or holes 
17 which extend through the side wall 14 of each catheter body. In a 
preferred design, six such holes, having a diameter of between 0.025 
inches and 0.075 inches and preferably 0.052 inches, are provided. Holes 
17 provide means for additional fluid communication between the vascular 
system and the lumen 12. Fluid material under relatively low pressure can 
easily pass through the holes 17. Vascular fluid material may therefore 
enter the holes 17 into the lumen of one of the catheters for withdrawal. 
Fluid material to be infused into the vascular system will be injected 
into lumen 12 at the proximal end of the catheter body 11 and will pass 
through the lumen of one of the catheters so that it may be introduced 
into the vascular system through holes 17. Because the catheter bodies 11 
are intended to be moved through a vascular pathway which may not be 
straight, the bodies are usually made of a polymeric material for 
flexibility, expandability and chemically compatible for use with a 
variety of fluid materials. 
The second distal zone 16 is spaced from the first distal zone by a 
distance of between about 0.15 inches and 0.25 inches. In a preferred 
design such distance will be 0.197 inches. Distal zone 16 has a plurality 
of pressure responsive exit slits 18 which permit fluid material to exit 
the catheter lumen in response to internal fluid pressure which exceeds a 
predetermined level. Pressure responsive exit slits 18 thereby serve as 
pressure valves for infusion purposes as described more fully in U.S. Pat. 
No. 5,250,034. A compression fitting 30 is assembled with and located at 
the proximal end of each catheter body 11. A tubular extension 36 is 
removably carried by fitting 30. A luer adaptor 37 is supported at the 
proximal end of extension 36 and is adapted to receive means for either 
introducing fluid into the lumen 12 or for withdrawing fluid therefrom, 
such as the hemostasis Y-adapter 31. Y-adapter 31 has a side portion 35 
terminating with side port 34, and a straight portion 32 with proximal 
port 33. Side portion 35 and straight portion 32 each have a lumen for 
fluid communication with lumen 12 of catheter body 11. Fluid material to 
be infused into or withdrawn from the vascular system through catheter 
body 11 will be introduced or withdrawn via side port 34. Clamps 39 are 
carried by the extension 36 in order to close fluid flow therethrough. 
A removable occluding or sealing member 60, descnbed in greater detail 
below, is inserted into lumen 12 of the catheter body 11 through straight 
portion 32 of the Y-adapter 31. 
With reference now to FIGS. 2, 3, and 4, one embodiment of the removable 
occluding member 60 is illustrated. Occluding member 60 has a flexible 
polymeric hollow shaft 61 having lumen 66 formed by its hollow interior. 
Located at the proximal end of shaft 61 is a hub 62 and a female luer 
adapter 63 connected with the hub 62. A sealing element in the form of an 
expandable balloon 64, also made of flexible polymeric material, with 
thickness between 0.0005 inches and 0.020inches, but preferably about 
0.010 inches, is carried at the distal end of shaft 61. Shaft 61 is 
arranged to extend through balloon 64. Balloon 64 is secured to shaft 61 
at the points where shaft 61 passes through it such as by adhesive or heat 
bonding bands 65. Distal end 71 of shaft 61 is closed and rounded for easy 
insertion through Y-adapter 31 into lumen 12. FIG. 2 illustrates balloon 
64 in its deflated or collapsed condition. FIGS. 3 and 4 illustrate 
balloon 64 in its inflated or expanded condition. As will be appreciated 
from FIG. 3, the outside diameter of shaft 61 transitions and necks down 
at shoulders 72 in the area where balloon 64 is connected to the shaft 61 
to form a reduced diameter shaft segment 67. The outside diameter of shaft 
61 on both the distal and proximal sides of balloon 64 is preferably a 
number 4 French, while the outside diameter of shaft segment 67 which 
extends through the balloon, will be a number 3 French. In this manner, 
when the balloon is collapsed, the outside diameter of the area between 
shoulders 72 with the balloon covering the reduced diameter shaft segment 
67 will be substantially the same as the outside diameter of shaft 61 on 
either side of the connector bands 65. Shaft 61 with the balloon in its 
deflated condition can thereby easily be inserted into the catheter body 
11 and maneuvered to a desired location without the balloon protruding and 
interfering with such insertion or engaging the inside walls of the 
catheter body, and thus possibly being damaged. 
When the occluding member 60 has been inserted into lumen 12 and it is 
desired to inflate balloon 64 in order to occlude or seal a portion of the 
lumen, a fluid material, such as saline, may be injected through female 
luer adapter 63 into lumen 66 within shaft 61. Exit hole 68 is located in 
the shaft segment 67 of shaft 61. Saline which is introduced into the 
shaft lumen 66 will exit hole 68 into the balloon 64 causing it to expand. 
When occluding member 60 is inserted into catheter body 11 and balloon 64 
is inflated as a result of the injection of saline through shaft 61, 
balloon 64 will, when adequately expanded, engage the inside surface of 
side walls 14 of catheter body 11, thus occluding lumen 12. In order to 
accurately position balloon 64 at a desired location within lumen 12 of 
catheter body 11, a radio-opaque marker 69, such as a band of platinum 
iridium, may be applied to the outside diameter of the shaft segment 67. 
Under fluoroscopic observation, the marker 69 can be observed as it is 
being inserted into the catheter body 11. A similar marker 70 is carried 
on the outside surface of catheter body 11 at a point which will designate 
zone 19 between the first distal zone 15 and the second distal zone 16. By 
lining up markers 69 and 70, balloon 64 can be positioned in the zone 19 
so that when it is inflated and the balloon engages the inside of walls 
14, it will block or occlude fluid communication between distal zones 15 
and 16. In order to remove any fibrin build up on the outside surface of 
catheter body 11, enzymatic material, such as urokinase, is introduced 
through side port 34 of Y-adapter 31, so that it will travel through lumen 
12 under elevated pressure. Distal flow of the enzymatic material will be 
blocked by balloon 64. The enzymatic fluid will cause the body of the 
catheter to radially expand and will be caused to pass from lumen 12 
through exit slits 18 to the outside surface of catheter body 11 where it 
will come in contact with any fibrin build up. As a result of the contact 
of the enzymatic material with the fibrin on the outside surface of 
catheter 11 and as a result of the mechanical effect of the radially 
expanding catheter body 11 caused by the pressurized fluid in lumen 12, 
fibrin will break up, solubilize and be carried away with the blood flow 
in the vascular system surrounding the catheter. As a result of such 
removal of the fibrin on the catheter surface, an environment for 
bacterial growth will be dissipated and the holes 17 and slits 18 will be 
unclogged by any build up of fibrin in these areas. 
Turning now to FIG. 5, an alternate embodiment of an occluding member is 
illustrated. In this embodiment, reduced diameter shaft segment 87 of 
shaft 81 will extend from transition shoulder 92 to the distal end 93. 
Balloon 84, which may be a non-compliant balloon made of expandable 
polymeric material having a preferred thickness in this embodiment of 
about 0.001 inches, serving as the sealing element will be secured to 
shaft 81 by adhesive or thermal bonding welded bands 85 so that balloon 84 
extends over a longitudinal distance larger than the longitudinal distance 
of zone 15. Radio opaque marker 89 can be observed under fluoroscopy 
during insertion in order to locate marker 89 at approximately the distal 
end 20 of catheter body 11 without the need for a marker on body 11 to 
line it up with. Distal end 93 of reduced diameter segment 87 will 
protrude through end hole 21 of body 11. When saline is injected through 
lumen 86 of shaft 81 it will exit hole 88 to fill up balloon 84 causing it 
to expand. When so expanded, balloon 84 will engage the inside surface of 
wall 14. In the case of the embodiment shown in FIG. 5, because the 
balloon 84 extends at least the entire length of zone 15, the inflated 
balloon will cover all of the holes 17 within the zone 15. Enzymatic fluid 
introduced into lumen 12 will again be caused to exit slits 18 in order to 
contact any fibrin material which may have built up on the outside surface 
of catheter body 11 in order to dissolve it. 
A further embodiment of an expandable occluding or sealing member is 
illustrated in FIGS. 6 and 7. In this embodiment, occluding member 110 
includes a flexible hollow polymeric shaft 111. The sealing element of 
this embodiment is a flexible covered mesh basket 112, which can be made 
either of metal or plastic. The basket 112 is attached to the distal end 
113 of the shaft 111. Basket 112 has a polymeric flexible covering 114. An 
adjusting wire 115 extends through the hollow center of the shaft 111 and 
is connected to the distal end 116 of basket 112. A handle 117 for 
gripping is located at the proximal end of wire 115. FIG. 6 illustrates 
wire mesh basket 112 in its collapsed state. Longitudinal movement of wire 
115 in the proximal direction will cause distal end 116 to move toward 
connection point 113 causing basket 112 to expand in a radial direction as 
illustrated in FIG. 7. In this manner, outer covering 114 of the wire mesh 
basket 112 is caused to engage the inside surface of walls 14 of catheter 
body 11 when the occluding member 110 is inserted into the lumen 12. A 
radio opaque marker may also be carried by the occluding device 110, in a 
manner similar to that described with respect to the embodiments of FIGS. 
2 and 5, in order to be able to locate the expandable covered wire mesh 
basket at a desired location within the catheter body 11. Moving wire 115 
in a distal direction will cause distal end 116 to move in a distal 
direction away from connection point 113 causing the covered wire mesh 
basket 112 to collapse into its collapsed state so that the occluding 
device 110 may be removed or repositioned within the lumen 12 of catheter 
body 11. 
In operation, an occluding member such as member 60 of the embodiments 
illustrated in FIGS. 1 or 2, or the occluding member 110 of the embodiment 
illustrated in FIGS. 6 and 7, is inserted through port 33 of the straight 
portion 32 of the Y-adapter 31 when it is desired to remove any build up 
of fibrin on the outside surface of the catheter body 11. In a catheter 
design which has zone 15, with holes 17, and zone 16, with slits 18, the 
sealing element of the occluding member is placed proximal of the first 
hole 17, within the area of zone 19 by fluoroscopically observing the 
radio opaque markers. The sealing element of the occluding member will 
then be expanded to engage the inside surface of walls 14 thus blocking 
any fluid flow distally of the sealing element. Enzymatic fluid is then 
injected via side port 34 into the lumen 12 of catheter body 11 under 
appropriate pressure so that it will exit lumen 12 through exit slits 18 
in order to come into contact with fibrin build up causing the fibrin to 
dissolve and dissipate. The introduction of the enzymatic fluid under 
appropriate pressure into lumen 12 will also cause catheter body 11 to 
radially expand enough to mechanically disrupt and cause a break up of the 
fibrin sheath on the outside surface of the catheter body. In addition, 
the mechanical effect of fluid exiting slits 18 will also result in 
breaking up the fibrin sheath. Accordingly, even if enzymatic fluid were 
not used but another therapeutic fluid or non-reactive fluid (such as 
saline) were used instead, the foregoing mechanical actions would be 
effective in facilitating removal of the fibrin. 
In the case of the embodiment shown in FIG. 2, when properly located, the 
balloon 64 can be inflated by the introduction of saline through lumen 66 
of shaft 61 until the balloon is fully inflated engaging the inside 
surface of side walls 14 thus blocking passage of any enzymatic fluid 
distally beyond the location of the balloon. After the enzymatic material 
or other therapeutic fluid has been injected and exited through the slits 
18, saline can be removed from the balloon by drawing it back out through 
the shaft 61. The occluding member 60 can then either be removed from the 
catheter body 11 by withdrawing it out of the Y-adapter 31, or its sealing 
element may be repositioned within the catheter body. If the catheter body 
11 is of a design without any side holes, the sealing element of the 
occluding member may be advanced to the distal end of the catheter. Once 
in place, the expandable sealing element of the occluding member is 
expanded or deployed, thus sealing off any flow in the catheter distally 
of the expanded sealing element. 
If the holes 17 of the catheter body also need to be cleared of fibrin 
material, this can be accomplished by collapsing the sealing element of 
the occluding member and repositioning it distally of zone 15, expanding 
it once again and reintroducing enzymatic material so that it may pass 
through the holes 17, thus dissolving any fibrin material within the holes 
17. 
After the outside surface of the catheter and the holes 17 are cleared of 
fibrin by the administration of enzymatic or other therapeutic material, 
the occluding member is removed from the catheter body and the catheter 
reused in its intended fashion. 
The present invention can thus be used to quickly and easily remove any 
fibrin build up or sheath which may be formed on the outside surface of 
the catheter body without having to mechanically strip the fibrin from the 
outside surface by using snares or baskets. Use of the present invention 
thus provides a means to eliminate the sudden release of fibrotic material 
which may travel to the patient's lungs and avoids the requirement of an 
additional entry site created in the body of the patient in order to 
insert snares or other mechanical devices needed to scrape the outside 
surface of the catheter body. Use of the present invention also eliminates 
possible damage to the catheter body, thus extending its useful life. 
Elimination of fibrin build up on the outside surface of the catheter body 
in a manner described in accordance with the present invention will reduce 
or eliminate possibilities of infection which would be promoted by the 
environment of a fibrin build up. 
This invention has been described and illustrated in connection with 
certain preferred embodiments which are illustrative of the principles of 
the invention. However, it should be understood that various modifications 
and changes may readily occur to those skilled in the art, and it is not 
intended to limit the invention to the constructions and operation of the 
embodiments shown and described herein. Accordingly, additional 
modifications and equivalents may be considered as falling within the 
scope of the invention as defined by the claims herein below. 
The embodiments of the invention in which an exclusive property or 
privilege is claimed are defined as follows: