Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Having pleats
Reexamination Certificate
2002-03-22
2004-08-10
Reip, David O. (Department: 3731)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Having pleats
C623S001130
Reexamination Certificate
active
06773457
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority of European Patent Application No. 01610036.4 filed Mar. 27, 2001.
TECHNICAL FIELD
The present invention relates to a medical device and, in particular, to an aorta graft device.
BACKGROUND OF THE INVENTION
An aorta graft is an endovascular prosthesis for placement in aorta in a weakened area, such as at an aneurysm of the abdominal aorta. An aortic aneurysm is an abnormal dilation or enlargement of the arterial wall of the aorta. If the aneurysm is not treated, it can rupture and abruptly cause a fatal blood loss out of aorta into the abdominal or thoracic cavity of patient.
The aorta graft is normally made of a tube of pliable material provided with a stent for anchoring the graft in its intended position within the blood vessel by exerting an outwardly directed radial pressure against the surrounding aortic wall. This requires in the area of the stent a relatively healthy aortic wall that can withstand the radial pressure for years. Patients diagnosed with aortic aneurysms are often in poor health due to other illnesses which increase the risk of complications associated with an operation. Most prior art aorta grafts are for the repair of abdominal aortic aneurysms (AAA) involving the pararenal and infrarenal aorta. Examples of such grafts are described in U.S. Pat. Nos. 5,984,955 and 6,016,810. Many of these grafts are bifurcated and extend into the iliac arteries. Aortic grafts of these types can typically be placed using transluminal, minimally invasive procedures where the graft is percutaneously introduced via a femoral puncture site, and the entire procedure can be performed using local anaesthesia.
With respect to aortic grafts for the repair of thoracoabdominal aortic aneurysms (aneurysms in the descending thoracic aorta) and thoracic aortic aneurysms (aneurysms in the ascending thoracic aorta including the aortic arch) only a few proposals for minimally invasive procedures have been made.
U.S. Pat. No. 6,099,548 proposes to advance the graft into the ascending thoracic aorta and to lock it to the aortic wall by expanding a stent in the proximal end of the graft. However, adjacent the heart the flow rate of blood through aorta is so high that the risk of dislocation of the proximal stent is considerable.
In a particularly lethal kind of aortic aneurysms the aortic wall is dissected to form a bogus lumen that establishes a parallel flow path for blood. The only method of repair is open surgery. In a so-called elephant trunk procedure a stented distal end of a secondary graft part is fixed in the descending aorta, and the proximal end of the secondary graft part is sutured to a primary graft part that is placed in the ascending aorta and anastomosed to the branch arteries carotis communis, subclavia and truncus brachiocephalicus.
During the operation the patient is subjected to cardiac arrest and systemic circulatory arrest, and although the patient has been cooled to a very low body temperature, such as 16° C., and selective cerebral perfusion is performed, the duration of the operation is a critical factor.
Dissections of type A where the aortic wall dissection is initiated in the ascending aorta pose a particular problem. With the prior art techniques the mortality is 75% within 24 hours of initiation of the condition and 90% within one week. The surgeon thus has extremely short time to prepare and perform the surgery.
SUMMARY OF THE INVENTION
A purpose of the present invention is to improve the efficiency of the surgical repair of implanting the aortic graft device.
With a view to this the aortic graft device according to the invention is characterized in that the primary graft part has an anchoring area positioned between an ascending portion extending to said proximal end and a descending portion extending to said distal opening, that the ascending portion is corrugated, and that the descending portion is at least partially non-corrugated.
The positioning and anchoring of the primary graft part can begin immediately after cardiac arrest has been obtained. The corrugations on the ascending portion of the graft facilitates setting of the ascending portion in a curvature following the path of the ascending aorta in the particular patient. This saves some time. A further major time saving is obtained in that the primary graft part is the first one to be positioned in the patient. After anchoring the primary graft part to the aortic wall, the ascending portion of the graft can be located in the ascending aorta and the descending portion of the primary graft part can be left hanging loose in the descending aorta. Time consuming suturing of the secondary graft part to the primary graft part is avoided which markedly reduces the duration of the critical part of the operation in which cardiac arrest and systemic circulatory arrest are required.
The non-corrugated area on the descending portion makes it possible to connect the descending portion of the graft to a secondary graft part or to the aortic wall at a subsequent operation. When the surgeon has performed the anchoring of the primary graft part he is aware of the time consumed and he can decide to insert a secondary graft part right away if time allows this, or to postpone placement of a secondary graft part or an alternative connection of the distal end of the primary graft part to the aortic wall to another operation. The surgeon also fixes the proximal end of the primary graft part to the desired site of the aortic wall in the ascending aorta.
The anchoring area positioned between the ascending and the descending portions of the primary graft part make it possible for the graft to be fixed to a portion of the aortic wall in vicinity of the three branch arteries on the aortic arch. The anchoring can be made to the distal side of the arteria subclavia at least at the upper portion of the aortic arch and possibly in an annular pattern following the aortic wall.
In an illustrative embodiment, the descending portion of the primary graft part is non-corrugated at least at said first connecting means, and preferably along its full length from said anchoring area to said distal opening. The non-corrugated area makes it easier to obtain a blood tight connection between the primary graft part and the tubular member connected to it.
The descending portion of the primary graft part is provided with at least one stent, and preferably provided with at least two stents, which are located near the anchoring area and at the distal opening, respectively. The stent resiliently acts on the descending portion to keep it open and non-kinking.
In a further embodiment the descending portion of the primary graft has a distal end area which is uncorrugated and unstented and has a length of at least 20 mm. The distal end area can be utilized to couple the primary graft to either a secondary graft or to the aortic wall. It is possible to perform suturing in the distal end area, but it is likewise possible to use the smooth surface character in the distal end area to obtain a pressure-tight sealing between the primary graft and the secondary graft.
The descending portion of the primary graft part is preferably supported by a stent at least along the majority of its length. By stenting, the descending portion is kept fully open, also when it is subjected to compressing or kinking actions on the exterior of the descending portion which is hanging freely floating in the aortic vessel downstream of the anchoring area. This is particularly useful when a secondary graft part is to be connected to the primary graft part at separate surgery.
In order to facilitate handling and placement of the primary graft at least the ascending portion of the primary graft part is precurved. The precurved shape reduces the size of bending forces required to keep the ascending portion in position during suturing of the anchoring area and thus minimizes the time spent on correcting the location of the primary graft part during suturing.
In a preferred embodiment, a wedge-shaped area of graft
Ivancev Krasnodar
Koul Bansi Lal
Godlewski Richard J.
Reip David O.
William Cook Europe ApS
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