Angiography catheter

The invention relates to an angiography catheter comprising a hose-like body with at least one lumen debouching at the distal end in an end opening, wherein the distal end has a permanent curvature and a number of openings is arranged in the wall. At least some of the openings are herein arranged in the curvature in a side of the wall remote from the end opening. The angiography catheter can be of the so-called "pigtail" type, with a circular curvature through substantially 360.degree., wherein openings are arranged in the first 180.degree. of the curvature in the outward facing portion of the wall.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to an angiography catheter comprising a hose-like 
body with at least one lumen debouching in an end opening at the distal 
end. The distal end has a permanent curvature and a number of openings is 
arranged in the wall of the catheter. 
2. Description of the Related Art Including Information Disclosed Under 37 
CFR .sctn.1.97-1.99 
Such a catheter is, for example, a diagnostic cardiac catheter which is 
guided via a blood vessel into the heart. A contrast liquid can be 
introduced via the lumen so that the contours of, for example, a ventricle 
of the heart of a patient can be made visible on an X-ray screen in a 
catheter laboratory. In accordance with the area of the blood vessel 
system of the patient to be examined, a catheter is used with a specific 
curvature, which curvature is designed such that the distal end of the 
catheter will assume a stable position in the intended area. 
With known angiography catheters of this type, the curvature can deform 
quite considerably during injection of the contrast liquid as a result of 
the reaction forces of the contrast liquid flowing in the curvature and 
spurting outward from the end opening. This can endanger the stable 
position of the end portion of the catheter. 
The invention now has for its object to improve a catheter of the type 
described in the preamble such that it also has a stable position during 
injection of the contrast liquid. 
This objective is achieved with an angiography catheter, as characterized 
in claim 1. Due to the openings arranged in the curvature in a side of the 
wall remote from the end opening, a quantity of liquid is discharged and 
the reaction forces resulting from the remaining liquid become accordingly 
smaller. The pressure in the curvature is thereby also lower whereby the 
"uncurling", as a result of a Bourdon spring effect, is likewise reduced. 
Moreover, a reaction force is herein generated which attempts to bend the 
catheter in a direction opposite to that in which the catheter is bent by 
the reaction force of the liquid coming out of the end opening. These 
effects largely cancel each other out so that during injection of the 
contrast liquid, even if this takes place at high pressure a very limited 
deformation, at most, of the permanent curvature of the catheter occurs. 
The angiographic examination can hereby take place more rapidly and 
accurately. 
The invention can be applied particularly well with an angiography catheter 
of the so-called "pigtail" type. The curvature herein is a circular 
curvature through practically 360.degree.. In the known "pigtail" 
catheter, the curvature is bent outward by the reaction force of the 
liquid spurting out from the end opening, whereby the desired shape of the 
curvature is disturbed and the direction in which the contrast liquid 
spurts out is moreover considerably altered. With the catheter according 
to the invention of the type, openings are arranged in the first 
180.degree. of the curvature in the outward facing portion of the wall. 
These openings drain off a portion of the liquid, whereby the forces in 
and on the curvature become smaller because the quantity of liquid and the 
pressure thereof in the curvature decrease. The liquid flowing outward 
through the openings causes a reaction force which results in 
strengthening of the curvature of the catheter and, thus, counteracts the 
"uncurling". 
The placing of the openings in the manner according to the invention 
moreover has the advantage that contrast liquid is better directed towards 
the apex of the heart ventricle under examination, so that the whole 
action of the catheter is improved. 
The openings arranged in the curvature are preferably additional to the 
usual openings in the portion of the basic body lying in advance of the 
curvature. The number of openings in the catheter, according to the 
invention, is thus larger than in a catheter according to the prior art, 
so that a more uniform egress of contrast liquid over a larger area is 
achieved. This moreover achieves that the total quantity of liquid coming 
out of the end opening is smaller and the pressure of the jet coming out 
of he end opening of the wall of the heart ventricle toward which this jet 
is directed during the examination, can decrease greatly. Heart arrhythmia 
occurring with catheters of this type, according to the prior art, are 
hereby avoided.

For elucidation of the principle of the invention FIG. 1 and FIG. 2 show 
next to each other, an angiography catheter of the "pigtail" type 
according to the prior art (FIG. 1) and according to the invention (FIG. 
2). 
The catheter 1 according to the prior art shown in FIG. 1 has, in the usual 
manner, a basic body 6 with a lumen. In FIG. 1 only the distal end is 
drawn which, as shown here, has a circular curvature 2 through slightly 
less than 360.degree.. The end of the lumen debouches into an end opening 
3. Arranged in the portion of the basic body 6 lying in advance of the 
curvature 2 is a number of openings 5 which connect the lumen to the 
environment. 
During use a contrast liquid is injected into the proximal end of the 
catheter, which liquid comes out at the distal end shown in FIG. 1 through 
the end opening 3 and the openings 5. The jet 4 coming out of the end 
opening 3 causes a reaction force on the curvature 2 which results in the 
"unrolling" of curvature 2. This situation is indicated with dashed lines. 
During the examination the catheter thus moves as a result of this 
unrolling effect so that the position thereof is not stable. 
The catheter 11 according to the invention shown in FIG. 2 likewise 
comprises a basic body 16 with a curvature 12 on the end thereof which is 
substantially a circular curvature through 360.degree.. Here the lumen 
also forms an end opening 13 out of which comes a jet 14 of contrast 
liquid during use. 
As shown in FIG. 2, in the first 180.degree. of the curvature, taken from 
the basic body, openings 17 are arranged in the side of the wall facing 
away from the end opening 13, that is, in the outward facing portion of 
the wall. During use of the catheter, jets 18 of contrast liquid egress 
through these openings 17. These jets 18 cause a reaction force which 
attempts to enhance the curvature 12 and thus acts counter to the reaction 
force caused by the jet 14. The effect is that the curvature 14 deforms to 
a limited degree at most, whereby a considerably more stable position of 
the curvature is obtained. 
The catheter shown in FIG. 2 is a preferred embodiment wherein the openings 
17 are additional to the openings 15 arranged in the conventional manner 
in the portion of the basic body 16 lying in advance of the curvature. 
These openings 15 correspond to the openings 5 in the catheter 1 according 
to the prior art. 
In this preferred embodiment, the number of openings in the distal end of 
the catheter is thus increased, so that the jet 14 finally coming out of 
the end opening 13 is considerably less powerful than according to the 
prior art. This also reduces the "unrolling" effect of the jet 14. 
As FIG. 3 shows, the jet 14 is usually oriented to the wall of the heart 
ventricle 21 during the examination of the heart 20 of a patient. Since in 
the preferred embodiment of the invention the strength of jet 14 is 
reduced, the irritation of the wall of the heart ventricle 21 is limited, 
so that the heart rhythm is not disturbed or much less so. 
FIG. 3 also shows that the catheter of the "pigtail" type described here is 
carried via the aorta 22 into the ventricle 21. Due to the specific shape 
of the curvature, the end portion of the catheter remains lying stably in 
the ventricle 21 in the manner shown. During injection of the contrast 
liquid the catheter, according to the invention, also retains its 
position. 
An additional advantage of the openings 17 arranged in the curvature is 
that the jets 18 of contrast liquid coming out therethrough penetrate well 
into the apex 23 of the heart ventricle 21 so that on an X-ray screen a 
clear image of the contours of the ventricle 21 can be obtained. 
Although the invention can be applied particularly favorably in the case of 
the described angiography catheter of the "pigtail" type, the invention 
is not limited to use with this type of catheter. In all angiography 
catheters with a curved end, openings can be arranged according to the 
invention in the wall of the curvature, in a side of the wall facing away 
from the end opening, in order to obtain the described effect of 
counteracting the deformation of the curvature by the jet coming out of 
the end opening.