Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-07-20
2003-05-06
Casler, Brian L. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S525000
Reexamination Certificate
active
06558368
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to catheters adapted to be inserted into the cardiovascular system of a living body and, more particularly, to a preshaped catheter having an improved distal end portion for providing more precise access to the right main coronary artery of the cardiovascular system.
Catheters are often used in the performance of medical procedures such as coronary angiography for injecting dye, or the like, into the cardiovascular system for diagnosis; and angioplasty to widen the lumen of a coronary artery which has become at least partially blocked by a stenotic lesion causing an abnormal narrowing of the artery due to injury or disease. In these techniques the distal end of a therapeutic catheter is introduced into the aorta by way of the femoral artery. The proximal end of the catheter is then manipulated so its distal end is inserted into the lumen of a selected coronary artery branching off from the aorta. A typical treatment procedure would involve initially inserting a guiding catheter into the cardiovascular system in the above manner, followed by the introduction of a suitable therapeutic device, such as a dilating catheter, a laser catheter, an atherectomy catheter, or the like. The therapeutic catheter is guided through the guiding catheter until its distal end portion is positioned adjacent the stenotic lesion in the coronary artery for use in reducing the blockage in the artery. In all such medical procedures, it is absolutely essential that the guiding catheter has the appropriate shape for proper alignment of its distal end relative to the coronary artery.
The most common catheter used in treatment of the right main coronary artery is what is often referred to as a “Judkins” catheter, which has a specially shaped distal end portion for facilitating insertion and engagement into the right coronary artery. However, there are some significant disadvantages to the “Judkins” catheter, such as its frequent inability to align perfectly coaxially with the selected artery and thus permit optimal treatment, and its inability to adequately support other therapeutic devices such as balloon catheters. Also, the Judkins catheter requires a 180 degree rotation and adroit manipulation to selectively engage its distal end in the right main coronary artery, which makes it more difficult to use effectively and efficiently.
In
FIGS. 1A and 1B
of the drawings, the reference numerical
10
refers, in general, to a well known prior art catheter, commonly referred to as a “Judkins” catheter. The catheter
10
is in the form of an elongated tubular member having a straight portion
12
(shown partially in
FIGS. 1A and 1B
) and a distal end portion. The distal end portion consists of a tertiary curved portion
14
, a secondary curved portion
16
, a primary curved portion
18
, and a tip portion
20
. The tertiary curved portion
14
extends from the straight portion
12
and is bent to form a curve of approximately 30°. The secondary curved portion
16
extends from the tertiary curved portion
14
and is bent in the opposite direction to the tertiary curved portion
14
to form a curve of approximately 30°. The primary curved portion
18
extends from the curved portion
16
and is bent to form a curve of approximately 90° and the tip portion
20
extends from the curved portion
18
. According to a typical Judkins catheter the curved portions
14
and
16
would have a radius of curvature of 10 and 5 centimeters (“cm.”), respectively, and the tip portion
20
would have a length of 1 cm. The catheter
10
is usually fabricated of a plastic material selected to exhibit flexibility and softness yet permit adequate “torque control” (i.e., the ability to transmit twisting forces along its length) so that it can be located and maneuvered precisely within a cardiovascular system by skilled manipulation of its proximal end, as will be described.
A typical cardiovascular system is shown in
FIGS. 1C and 1D
and is referred to, in general, by the reference numeral
22
. The system
22
includes an aorta
24
comprised of a descending aorta
24
a
, an ascending aorta
24
b
, and an aortic arch
24
c
which extends from the descending aorta
24
a
to the ascending aorta
24
b
over a curve of approximately 180°. The ascending aorta
24
b
then branches through a right ostium
26
and a left ostium
27
into a right coronary artery
28
and a left coronary artery
30
, respectively. An aortic valve
32
extends between the right coronary artery
28
and the left coronary artery
30
and is connected to the heart (not shown). As better shown in
FIG. 1D
, the right coronary artery
28
and the left coronary artery
30
are normally angularly spaced approximately 120°.
The prior art Judkins catheter
10
of
FIGS. 1A and 1B
is designed for use as a diagnostic catheter in the right coronary artery
28
but is also used as a guiding catheter for treatment of stenotic lesions, or the like. To this end, the catheter
10
is inserted into the system
22
and is manipulated so that, ideally, the tip portion
20
of the catheter
10
is positioned through the ostium
26
and into the lumen of the right coronary artery
28
and used to guide other therapeutic devices such as balloon, laser or atherectomy catheters, or the like (not shown) into the right coronary artery
28
.
To assist in advancing the catheter
10
through the system
22
, a relatively stiff wire is initially inserted into the catheter
10
to straighten it. After the catheter is inserted into the ascending aorta
24
b
, the wire is withdrawn, causing the catheter to position itself along the wall of the ascending aorta
24
b
, 1 to 2 cm. above the ostium
27
of the left coronary artery
30
. As a result, the tip portion
20
of the Judkins catheter
10
points away from the ostium
26
of the right coronary artery
28
and must be rotated 180°. During this rotation, the catheter
10
will suddenly descend about 3 cm. until the tip portion
20
hopefully aligns with the ostium
26
of the right coronary artery
28
in a coaxial relationship as shown in FIG.
1
C.
However, due to the particular configuration of the Judkins catheter
10
, the tip portion
20
is often misaligned with the ostium
26
of the right coronary artery
28
and is not located coaxially with the latter artery. Thus, when an inner catheter or therapeutic device such as a balloon catheter (not shown) is passed through the catheter
10
, the former often strikes the wall of the ascending aorta
24
b
or the right coronary artery
28
increasing the risk of damage. Also, due to the fact that the curved portion
18
is positioned adjacent to the wall of the ascending aorta
24
b
which contains the ostium
26
of the right coronary artery
28
and is a considerable distance from the wall of the ascending aorta
24
b
opposite the ostium
26
, the catheter
10
does not provide support for other catheters or devices that are passed through the catheter
10
. This problem is described in depth in Danforth U.S. Pat. No. 4,909,787. Due to the lack of support, when axial forces are exerted on the tip portion
20
, such as when a dilation balloon is advanced, the tip portion
20
has a tendency to push back from the ostium
26
causing the tip portion
20
to dislodge from the lumen of the right coronary artery
28
and the therapeutic device to prolapse in the ascending aorta
24
b
. Thus, the therapeutic device loses its preferred orientation within the ascending aorta and right coronary artery. After this occurs, further advancement of the therapeutic device becomes nearly impossible because the Judkins catheter no long provides adequate support to the highly flexible shaft of the therapeutic device as one attempts to push the therapeutic device across the tight stenosis.
The lack of “backup” support happens because the Judkins catheter was not originally intended to serve as a conduit for other therapeutic devices into a patient's arterial system. Rather, the Judkins catheter was designed and configured merely to prov
Casler Brian L.
Crompton Seager & Tufte LLC
Thissell Jeremy
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