Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent combined with surgical delivery system
Reexamination Certificate
2000-12-18
2004-07-20
Pellegrino, Brian E. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent combined with surgical delivery system
C606S108000, C606S191000
Reexamination Certificate
active
06764503
ABSTRACT:
TECHNICAL FIELD
This invention relates to a device for safely locating a stent or stent graft at a diseased site in order to treat a stenotic and expansive disease such as an aneurysm of an artery and other disease conditions.
BACKGROUND ART
An aneurysm which grows due to hardening or inflammation of an artery, when left untreated expands gradually and fatally ruptures creating a disease condition that has no prognosis. Medicine has little effect on this type of disease condition. Therefore, in order to cure an aneurysm, a surgical operation using an artificial blood vessel, e.g. an operation involving removal of cancer tissue and of replacement by the artificial blood vessel has traditionally been performed. However, this type of disease condition is often experienced by old which increases the likelihood of multiple organ failure such as disorders of the brain, heart the kidneys, etc. In addition, the surgical operation is often excessively invasion. Thus, a surgical operation for this disease condition that is limited to safe technique which can avoid the danger of these difficulties is desired. Accordingly, much attention has been paid to the treatment of blood vessels using catheters which is less invasion.
A stent is an artificial tubular structure that is inserted into an internal tubular organ such as a blood vessel for the purpose of supporting it. When an internal tubular organ such as a blood vessel, gallbladder, esophagus, intestines, urethra, etc. suffers stenosis or deformation, stent is inserted into the internal tubular organ to support it so that the stenosis and deformation are prevented. A stent which has been widely applied clinically in order to treat an arterial stenotic disease is a cylinder formed of a wire mesh or spring made of stainless steel or a shape memory alloy (NiTi). The cylinder is formed to be shrinkable or expandable repeatedly in a radial direction. A stent graft is a polyester or Teflon artificial blood vessel in which a stent cylinder formed of mesh or a spring made of stainless or nickel titanium is sewed therein. Stent grafts have effectively been used to treat aneurysms. Such stents and stent grafts are disclosed in JP-A-7-24072, JP-A-7-47134, JP-A-7-500272 (PCT), JP-A-8-299456 (PCT), JP-A-8-502428 (PCT) and JP-A-8-511487 (PCT).
Stents and stent grafts are located in diseased portions of blood vessels through catheters. Specifically, the stent or stent graft is compressed to have a diameter smaller than the inner diameter of a fine catheter and is housed in the catheter. The stent or stent graft is inserted from an incised part of a peripheral artery such as a femoral artery into the diseased portion of the blood vessel. The stent or stent graft is extruded from the catheter and expanded to a prescribed diameter in a radial direction. The stent or stent graft is further located in the diseased portion of the blood vessel, thereby expanding an artery stenotic disease and closing the aneurysm while reconstructing a blood flow. The treatment using the stent or stent graft is acceptably invasive. Therefore, it can reduce the burden imposed on a patient, and can be also applied to aneurysm diseases. Thus, this treatment is effective for patients suffering from arterial stenotic diseases and expansive diseases.
However, conventional stents and stent grafts cannot be contracted again after they have been discharged from a catheter to expand and located in a blood vessel. Therefore, when a disorder of the blood stream and internal organ happen because of erroneous positioning of the stent or stent grafts, they cannot be moved or recovered.
Further, in order to ensure closure of an aneurysm conventional stent grafts must be located over a wider range including not only the aneurysm but also the normal artery on the central and peripheral sides of the aneurysm so that the contact between the stent graft and the internal face of the artery is assured. However, in this case, a problem is created when the stent graft also closes the main artery which branches from the vicinity of the aneurysm to generate organ disorder (hereinafter referred to as “position abnormality”). For example, in the case of an abdominal aortic aneurysm, when the artery such as a renal artery, inferior mesenteric artery, internal iliac artery, etc. is closed, there can be renal failure or colon ischemia. Likewise, in the case of a thoracic aortic aneurysm, when an intercostal artery is closed, there can be spinal cord ischemia, leading to serious complication of paralysis of a lower half of a patient's body.
The inventor of the present invention supposed as follows. It is assumed that a stent or stent graft which can recovered from the body can be located temporarily at a diseased portion of a blood vessel before the conventional stent or stent graft is located at the diseased part. In this case, if a dangerous portion where a blood flow disorder may occur when the conventional stent or stent graft is located in the blood vessel and a safe portion where no blood flow disorder exits are taken beforehand as video information, the conventional stent can be located at the safe point of the blood vessel. On the basis of this idea, the inventor of the present invention proposed a temporarily locating type stent or stent graft which can be recovered from the body after it is temporarily located (JP application No 9-151372).
Hereinafter, in the specification, a stent or stent graft which can be located temporarily at a diseased portion of a blood vessel is referred to as a “temporarily locating type stent or stent graft”. On the other hand, the conventional stent or stent graft, which is permanently located at the diseased portion should be referred to as “permanently locating type stent or stent graft, but will be referred to as simply “stent or stent graft” as they are traditionally called.
In
FIG. 12
, reference numeral
111
denotes a temporarily locating type stent proposed by the inventor of the present invention. The temporarily locating type stent
111
is composed of a stent body
112
at the front and mast lines
118
at the rear. The stent body
112
has three elastic rings
114
each formed in a ring shape by a metallic wire bent in a zigzag manner. Each elastic ring
114
is made of a material such as stainless steel, titanium, shape memory alloy, etc. Around the elastic ring
114
, eight coupling wires
115
are arranged at regular intervals in a circumferential direction of the ring. These coupling wires
115
are welded or soldered on the elastic rings
114
at their points of intersection of them to form an elastic cylindrical body
114
. The elastic cylindrical body
113
is aligned with parallel portions
116
of the coupling wires
115
. The mast lines
113
whose tips
119
are connected to the parallel portions
116
in the stent body
112
extend rearward as bundle. The coupling wires
115
and mast wires
11
S are made of continuous shape memory alloy. The bundle of the mast wires
113
has a diameter which is slightly smaller than the inner diameter of a catheter
131
. The mast wires
11
S have a length sufficient to penetrate through the catheter
131
and to be operable outside the body when the stent body
112
is located at a prescribed position in a blood vessel. The stent body
112
and the mast wires
118
are sufficiently rigid to endure extrusion from the catheter
131
by manipulation from outside of the body and to be pulled into the catheter
131
. The catheter
131
is equipped, at its outlet with an R-shape so that the stent body
112
can be contracted smoothly and received in the body.
The temporarily locating type stent or stent graft can be used to determine beforehand, as video information, the dangerous part where the blood flow disorder may happen in the diseased portion in e.g. the blood vessel, and a safe port where no blood flow disorder exists. This temporarily locating type stent permits the permanent locating type stent to be located on the safe point of the diseased portion. However, the temporarily locating type stent ta
Butzel Long
Ishimaru Shin
Pellegrino Brian E.
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