Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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COMBlNATION ARTERIAL STENT
Backaround of the Invention
Generally this invention relates to stents for emplacement within
interior body lumens. More particularly, this relates to a combination stent
wherein one stent is of a different size than the other stent.
The use of stents to maintain iumens of the body open in order to
allow the passage of fluids therethrough, has become quite common.
Particularly useful are coronary stents which allow the coronary arteries to
be maintained patent even when there are lesions in these arteries due to
diseases such as arteriosclerosis. These stents are also useful for such as
the aorta or the iliac artery.
One particular area where stents are seen as useful are at the
junction of the iliac arteries into the aorta. However, it can be appreciated
that due to the difference in diameter between the iiiac arteries and the
aorta, it would be a complex problem to create a stent which would hold
open both the aorta at the junction of the arteries and one or both of the
arteries. This invention addresses such a problem.
Summary of the Invention
This invention comprises a stent which may be emplaced into the
lumen of the body. The stent has an expandable first section with a first
diameter and an expanded second diameter larger than its first diameter.
There is also a second section connected to the first section, the second
section contains a third diameter and an expanded fourth diameter which
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is larger than the third diameter. A final criterion to this invention is that
the second diameter is different from the fourth diameter. Thus, the
device may be emplaced between lumens of different sizes.
One particular method of manufacturing this stent is to provided the
stent with a first portion which contains a cylindrical shape and a
longitudinal axis. The cylindrical shape contains an array of slots arranged
around the diameter of the cylinder. The slots have a relaxed dimension
and an enlarged dimension around the circumference of the cylinder. The
enlarged dimension of each of the slots causes the cylindrical shape to
increase in diameter. Also, it causes the slots to decease in lengths so that
the cylindrical diameter of the stent in its first portion enlarges during the
enlargement of the first portion. There is also contained on such a stent
a second portion very similar to the first portion. It too contains an array
of slots arranged around the diameter of a second cylinder. It too contains
an enlarged dimension and a relaxed dimension. However, importantly, in
order to make this invention, the first portion slot lengths are of a
different
size, typically greater than, the second portion slot lengths. Thus, the user
is able once again able to enlarge the first portion to a different size than
the second portion.
One of the important ways of causing such an enlargement is too
provide a balloon catheter which is ideally formulated to create such a
mechanism. The catheter comprises a generally cylindrically expandable
length. The length has first sections, each of which have expanded
diameters. Again, however, each of the first and second expanded
diameters are of different dimensions. Thus, when emplaced on the first
and second stent portions, respectively, the user is again able to enlarge
the first portion to a different diameter than the second portion.
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Ideally, this stent can be placed at the junction at
the aorta and the iliac arteries, where the size of the
lumens are typically different. In use, therefore, the
device provides the surgeon with a useful tool to holding
open junctions of various sized lumens.
In accordance with an aspect, there is provided a
stent for emplacement into a body lumen comprising:
a first portion having a cylindrical shape and a
longitudinal axis, containing an array of slots
arranged around the diameter of said cylinder, said
slots having a relaxed dimension and an enlarged
dimension around the circumference of said cylinder,
whereby in said enlarged dimension, said cylindrical
shape increases in diameter, and said slots having a
predetermined length when said slots are in said
relaxed dimension; and
a second portion connected to said first portion, said
second portion having a cylindrical shape and a
longitudinal axis, containing an array of slots
arranged around the diameter of said cylinder, said
slots having a relaxed dimension and an enlarged
dimension around the circumference of said cylinder,
whereby in said enlarged dimension, said cylindrical
shape increases in diameter, and said slots having a
predetermined length wherein said slots are in said
relaxed dimension; and
whereby said first portion and said second portion are
created from a single thin-walled metallic tube and wherein
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said first portion slot lengths are greater than said
second portion slot lengths.
Description of the Drawings
The invention described above will be better
understood in conjunction with the following drawings
wherein:
Figures la, lb and lc describe the various methods of
manufacture of the stent of the present invention;
Figure 2 shows a stent of the present invention placed
within the body;
Figure 3 shows a balloon useful for placing the stent
of Figure 2 within the body;
Figure 4 shows a placement of two stents of the
present invention within the body;
Figure 5 shows a cross sectional view of Figure 4
taken across lines A-A of Figure 4; and
Figure 6 shows yet another alternate embodiment of the
invention.
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Detaiied Descriotion of the Invention
As seen in the drawings there is contained in this invention an
articulated or stepped stent 10 having two sections. The first second 12
has a given length 11 and a given diameter d1. The second section 14 has
a given second given length I. and a second given diameter d2. Each of
these sections 12, 14 are connected by a connector 16. The first section
12 similariy contains a series of elongated slots 18 of a first length s1.
The second section simiiariy contains a series of elongated slots 20 of a
second length s2. The size of the first length s1 will be different than the
size of the second length s2. Similarly, the stent 10" of Figure 6 contains
similar diameter sections 12", 14", but different length slots 18" (s1), 20"
(s2)' the stent 10" of Figure 6 produces the same result as the stent of
Figures lc and 2, according to this invention.
In use therefore the stent 10 of the present invention may be placed
at the junction of the iliac artery and the aorta as seen in Figure 4. The
size of the first section 12 will be enlarged to accommodate the size of the
aorta. The size of the second section 14 will be enlarged to accommodate
the size of the iliac artery, different than the size of the aorta. It will be
appreciated therefore, that the sizes of the slots 18, 20 when in the
enlarged state will expand to different sizes in order to accommodate the
lumens to which the sections of the stent are emplaced.
Manufacture of the stent of Figure 2 is described below. First, a
piece of stepped tubing 100 is designed so that there is a neckdown
roughiy in the place where the first section 112 is attached to the second
section 114. Then, a cylindrical portion of tubing 114 is removed,
specifically at the area of the neckdown of the stepped tubing forming
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connector 116. Then, slots 118, 120 are emplaced within the first and
second sections 112, 114, wherein the second sections 114 contains
smaller slots 120 than in the first section 112. Thus, when enlarged the
second section 114 cannot be enlarged to be the size of the first section
112. In other words, both sections 112, 114 have different initial and final
sizes.
Similarly, as seen in Figure 3, a stepped balloon 200 is useful to
emplace the stent of this invention. The balloon contains a first section
202 which is useful to be emplaced within the first section 12 of the stent
10 described above. The second section 204 of the balloon 200 is
emplaced within the second section 14 of the stent 10 described above.
When enlarged, the balloon 200 of present invention enlarges each
respective section 12, 14 of the stent 10 to its enlarged size for
emplacement within a lumen of the body.
Finally as seen in Figures 4 and 5 the stents 10, 10' of the present
invention may be useful in combination with a complimentary stent to
enlarge both iliac arteries and the aorta simultaneously. Here, the size of
the first section 12, 12' is roughly one-half the size of the aorta. The size
of the second section 14, 14' of the stents 10, 10' are roughly the size of
an iliac artery. When placed together, these articulating stents hold open
both iliac arteries (by enlargement of both second sections 14, 14' of each
of the stents 10, 10') and also holds open the aorta as seen in Figure 5 (by
enlargement each of the first sections 12, 12' of the stents 10, 10'
described in Figures 4 and 5). Thus, the combination proves quite useful
for one with artherosclerosis in many blood vessels, and also for anchoring
a prosthetic graft to a stent in such procedures.
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It will be appreciated that the above described invention may be
useful with various modifications and minor alterations to the design of the
present invention. Therefore, the scope of the invention in intended to be
encompassed by the appended claims and their equivalents.
