Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent combined with surgical delivery system
Reexamination Certificate
2001-07-18
2003-12-30
Milano, Michael J. (Department: 3731)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent combined with surgical delivery system
C606S194000
Reexamination Certificate
active
06669718
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to a device and method for delivering an expandable endoluminal prosthetic device, such as a stent, and more particularly to a device and method for placing a bifurcated stent such that only a single incision into a patient need be made.
Expandable surgical devices, such as stents and angioplasty balloons, are used in a variety of places in the human body to support various anatomical lumens, such as blood vessels, respiratory ducts, gastrointestinal ducts and the like. Conventionally, these devices are deployed in regions of stenosis or constriction in the target body lumen to hold the lumen open, thus obtaining a patent lumen and preventing immediate or future occlusion or collapse of the lumen and the resultant obstruction of fluids flowing therethrough. Because stent and balloon implantation is a relatively non-invasive procedure, it has proven to be a favorable alternative to surgery in, for example, certain cases of vascular stenosis. Bifurcated devices, with their trunk and branching configuration, are particularly well-suited for use in branching body lumen systems, such as in the coronary vasculature (which include the right, left common, left anterior descending and circumflex arteries and their branches) and the peripheral vasculature (including branches of the carotid, aorta, femoral, popliteal, and related arteries). Placement of such a bifurcated device can be rather complicated, often involving approaching the bifurcated section of the artery through at least two side branches or through the trunk plus one side branch. This procedure can be not only time-consuming, but also lead to more incision sites in the patient's body, as well as necessitate more complicated maneuvers for the surgeon. Procedures for placement of a bifurcated stent are described in U.S. Pat. No. 5,720,735 to Dorros, entitled “Bifurcated Endovascular Catheter” and U.S. Pat. No. 4,994,071 to MacGregor, entitled “Bifurcating Stent Apparatus and Method”. In these patents, which are representative of the state of the art, each of the branches has a dedicated guide wire to guide the placement of balloons, stents, stent grafts or grafts into a bifurcated anatomical lumen. This redundancy can lead to increases in the overall size, cost and complexity of delivery devices.
Accordingly, there exists a need for an apparatus used to place bifurcated stents and related surgical devices into a body lumen such that simpler surgical procedures are enabled, with a concomitant decrease in incision number or size and related invasive steps, thereby reducing patient trauma associated with complex medical procedures.
SUMMARY OF THE INVENTION
This need is met by the present invention, where the placement of a stent becomes simplified by the use of a single delivery catheter, using only a single incision in only one location. The present apparatus and method allow for placing non-bifurcating stents in a side branch of a bifurcating lumen, as well as for placement of all kinds of bifurcating stents anywhere in the body, with or without a graft. While it can be readily appreciated that the device described herein is applicable for use in numerous endoluminal devices, and in a variety of bifurcated body lumens, much of the subsequent discussion is limited to the example of a bifurcated stent for use in preventing an abdominal aortic aneurysm (hereinafter referred to as triple A), where such a device is commonly known as a triple A graft stent. Such a stent includes a near side branch section, far side branch section, and a trunk section joined to adjacent, or hinged ends of the two branch sections. Furthermore, it will be appreciated that the expansion of the triple A graft stent and related stents can be effected by plastic deformation due to balloon pressure, or triggering of elastically stored energy in the stent (such as with bistable stents or elastic or superelastic expansion).
According to an embodiment of the present invention, a catheter for inserting, deploying and removing a bifurcated surgical device is disclosed, where preferable surgical devices include bifurcated endoluminal stents, stent-grafts, grafts and balloon angioplasty mechanisms. The catheter, with an elongate hollow body, narrow proximal end and widened distal end is insertable into a single percutaneous incision site. The hollow body houses a central catheter wire that is used to deploy a stent mounted to the catheter. The distal end of the elongated body includes a flanged, exaggerated generally cylindrical portion configured to sheath the ends of the branch sections of the bifurcated stent, thus ensuring a small cross-sectional area for the entire as-inserted combination. The central catheter wire includes two leg portions connected at a common end to a trunk portion. The two leg portions of the central catheter wire are biased to a closed position, so that they are in a substantially side-by-side, parallel relationship, both effectively parallel with the trunk portion. This bias is important for establishing a small cross sectional area of the wire once the stent has been deployed. In stents that rely on balloons for expansion, this bias in the central catheter wire also helps to bring the deflated balloons together for improved ease of catheter removal. Prior to the deployment of the bifurcated surgical device, the bias is designed to be overcome by inherent spring forces in the branches of the bifurcated surgical device, which needs to expand to approximate the angle formed between the main and branching body lumens. This bias in the bifurcating surgical device is such that a substantially Y-shaped intersection is formed, which also induces the catheter to assume such a shape upon unsheathing of the bifurcating surgical device.
The coaxial arrangement between the components of the present system and the stent, as well as the relative axial movement between them permit both simple operation coupled with unobtrusive cross-sectional dimensions. Operability is further enhanced by the inclusion of position-indicating markers with steerable features. In addition to providing indicia of stent axial (or translational) position relative to the catheter, these markers provide readily-apparent indicia of the angular position of the device vis-à-vis the body lumen to enable accurate positioning of the stent. To enhance patient safety, the catheters of each of this and the following embodiments may optionally include a flexible housing that can follow the angular movements between the branches easily, while it smoothens the functioning of the device.
Alternately, the apparatus can be adapted to accept self-expanding stents, where the bifurcated balloon is replaced by multiple travelling sheaths that work in cooperation with tension and pushing elements within the catheter for removal of the sheaths from the stent surface. In this configuration, an additional wire, called a sheath deployment wire, is disposed adjacent the central catheter wire in the same hollow portion of the elongate body. The two wires work in conjunction with one another, as the sheath deployment wire is used to push the self-expanding stent and one or more of the stent-restraining travelling sheaths farther into the aorta such that the stent and sheaths are entirely beyond the body lumen bifurcation point. As previously discussed, the stent branches are of such spring bias that their tendency to splay is greater than the ability of the central catheter wire leg portions to stay together. This bifurcation allows one of the stent branches to be positioned in each of the iliac arteries upon partial pullback of the stent. Once the pullback has been accomplished, and the stent sheaths have been seated adjacent the body lumen bifurcation point, the central catheter wire, which now includes a series of mechanical stops along its trunk section, can be translated relative the stent such that it engages the travelling sheaths surrounding the far side branch and the trunk, moving them away from their corresponding ste
Baxter Jessica R
Dinsmore & Shohl LLP
Milano Michael J.
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