Patent Application
20060259127
Not applicable.
Not Applicable
1. Field of the Invention
The present invention relates generally to the field of minimally invasive techniques using endoluminal prostheses, such as stents, grafts, stent-grafts, filters, and the like for treatment of arterial or venous disease, including the repair of aneurysms and prevention of embolic events. More particularly, the present invention provides methods, systems, and devices for anchoring an endoluminal prosthesis, particularly where the lumen to be treated does not have sufficient landing area for anchoring the endoluminal prosthesis at the proximal or distal portion. The present invention also provides methods, systems and devices for anchoring an endoluminal prosthesis where the vasculature is tortuous near the diseased region, or the vasculature changes tortuosity with time.
2. Background of the Invention
A number of medical procedures involve or can be supplemented with the placement of an endoluminal prosthesis, such as a stent, graft, stent-graft, filter, or combination thereof. These endoluminal prostheses, commonly referred to as devices, can be implanted in a lumen, such as a blood vessel or other natural pathway of a patient's body. In order to provide delivery to the treatment location, such devices are typically placed in a small diameter delivery system and then advanced through the body lumen to the site where the device is to be placed. Upon delivery to the treatment location, known devices employ techniques such as plastic deformation, elastic recovery, superelastic recovery, thermal recovery, or balloon expansion to expand the device to a larger diameter. This expansion allows the device to engage the inner wall of the body lumen and anchor the device. In addition, the device may engage the inner wall of the body lumen with hooks or barbs.
A disadvantageous characteristic that many prostheses have in common is a requirement of a region of healthy tissue in which to place the device so as to provide appropriate anchoring forces. Of particular relevance for the present invention, is treatment of vascular aneurysms and treatment of occlusive disease.
Vascular aneurysms are an abnormal dilation of a blood vessel, resulting from a weakening of the arterial wall due to disease or genetic predisposition. Vascular aneurysms can occur in any blood vessel, although most occur in the aorta and peripheral arteries. The majority of aortic aneurysms occur in the abdominal aorta (commonly referred to as “abdominal aortic aneurysms”), usually beginning below the renal arteries and often extending into one or both of the iliac arteries. Aneurysms also occur in the thoracic aorta, usually beginning near the aortic arch, and extending peripherally to the renal arteries. All aneurysms, in both the aortic and peripheral arteries exhibit the possibility of rupture when the vessel wall becomes too thin to tolerate vascular loading. In the case of thoracic and abdominal aortic aneurysms, rupture is often fatal.
Treatment of an aneurysm occurring near a branched region presents numerous difficulties in device design. This is because the zone of healthy tissue between the branching arteries and the aneurysm is reduced by the progression of the disease. In advanced cases the aneurysm may be so large as to have almost reached the branched arteries, thereby providing an anchoring region that is too small to sufficiently anchor the device. Therefore, it would be desirable to have a device that could anchor in a region of healthy tissue remote from the diseased region.
In addition, progression of disease may cause increased tortuosity or angulations of the aneurysm relative to the anchoring region. This change in vascular orientation makes anchoring the device difficult, because the increased tortuosity or angulation tends to pull and twist the device. In some cases this can result in dislodgement of the device from the anchoring region. Therefore, it would be desirable to have a device, which could accommodate changes in vessel orientation while maintaining adequate anchoring forces.
Similar phenomena occur in occlusive disease. In occlusive disease, the vessel becomes narrow as a result of the build-up of plaque and other occlusive materials. For example, in occlusive disease occurring in the iliac artery, a stenosis, or narrowing of the artery may occur near the bifurcation of the common iliac. Placement of a device in this region can be difficult because the disease state is such that placement of a stent or stent-graft in the common iliac or external iliac may prevent blood flow to the internal iliac. Therefore, it would be desirable to have a device that could anchor in a region of healthy tissue remote from the diseased region.
Arterial or venous disease can also occur in regions of high curvature, where placement and anchoring of a device can be particularly difficult. For example, in the thoracic arch, it can be very difficult to place a device with sufficient anchoring force. Similarly, placement of arterial or venous filters can also occur in regions of high curvature.
In view of the foregoing, it would be desirable to provide a prosthetic device and method of deploying and anchoring a device that overcomes drawbacks of previously known stent, stent-graft, and filtering systems. It is an object of the present invention to provide a device and method that can anchor in a region of healthy tissue that is remote from the disease location. It is a further object of the present invention to provide a device and method that is readily deployable in tortuous vessels where the region to be treated is in a region of high curvature. Moreover, it is an object of the present invention to provide a device and method that accommodates changes in the tortuosity of the vessel over time. In addition, it is an object of the present invention to provide a device and method that can be deployed in sequence, whereby the anchoring body is deployed prior to positioning of the main body, which may comprise a stent, stent-graft, filter, or other device. Moreover, it is an object of the present invention to provide a device and method with a first body that may be deployed in a vessel having a large diameter, and a second body that may be deployed in a branch vessel having a smaller diameter or vice versa.
It is a further object of the present invention to provide a device capable of being deployed in a bifurcated or branched vessel that enables a first body of the anchoring system to be deployed in a trunk vessel having a first longitudinal axis, and a second body of the anchoring system to be deployed in one or more branch vessels having longitudinal axes forming an angle with the first longitudinal axis.
It is a further object of the present invention to provide endoluminal prostheses which accept variations in geometry along body lumens without compromising their therapeutic effectiveness. It is a further object of the present invention to provide a device and methods for its placement which would allow flow to side branches and bifurcated regions while providing sufficient anchoring force to support the device. It is a further object to provide adaptable prostheses and methods for their placement which would facilitate effective treatment of widely varying luminal system geometries without requiring an excessive inventory of prostheses to chose from.
The present invention is an endoluminal prothesis consisting of an anchor body and a main body for the treatment of vascular disease, especially when such disease requires the ability to anchor in a region remote from the diseased tissue. Methods of deploying a stent, stent-graft, or filtering system constructed in accordance with the present invention are also provided.
The foregoing and other objects and advantages of the invention will be appreciated more fully from the following description thereof, with reference to the accompanying drawings wherein:
In the preferred embodiment the device consists of two separate bodies, an anchor body (1) as shown in
An anchor body (1) is shown in
The tapered section (104) is made of thin longitudinal members (105) and terminates in a straight tube section (106). In the preferred embodiment, the straight tube section (106) is a section of the original tube stock that the entire anchor body (1) is made from. In an alternate embodiment, longitudinal members (105) can be similar in form to diagonal members (103) so long as they taper to straight tube section (106). In a further alternate embodiment, straight tube section (106) could have the same cut pattern as cylindrical section (102) but has not been fully expanded so that in the deployed configuration it remains at a reduced radius from cylindrical section (102).
The main body (2) is shown in
Tapered section (204) is made of thin longitudinal members (205) and terminates in an intermediate straight tube section (206) that is a section of the original tube stock that the entire anchor body (1) is made from. In an alternate embodiment, longitudinal members (205) can be similar in construction to diagonal members (203) so long as they taper to straight tube section (206). In a further alternate embodiment, tube section (206) could have the same diagonal cut pattern as cylindrical section (202) but has not been treated to expand so that in the deployed configuration it remains at a reduced radius from cylindrical section (202). The intermediate tube section (206) transitions to a partially expanded spherical section (207) made of a lattice of slender diagonal members (208) that can be expanded in the radial direction. In an alternate embodiment the partially expanded section (207) could be oval in shape and mate with an oval shaped tube section (106). In this alternate embodiment, this would reduce the rotational freedom of the interface about the long axis of the device and therefore prescribe the angular orientation between the two. Radiopaque markers could then be used to verify an certain angular orientation at deployment. Again, the pattern of the diagonal members (208) can be varied and depends on the application, material, and desired stiffness. In the preferred embodiment they are simply shown as a diamond pattern, but utilization of alternate patterns such as “U,” “V”, “W”, or “S” shapes to provide the ability for radial expansion will be apparent to one skilled in the art.
Spherical section (207) transitions into an end straight tube section (209). End straight tube section (209) may have cut slots in it giving a diagonal brace pattern, but it is substantially unexpanded and is most conveniently the radius of the original tube stock from which the device is manufactured.
In the preferred embodiment, anchor body (1) is installed through a catheter and deployed into the vessel at a location of relatively healthy tissue that is proximal to the damaged tissue. Once the Anchor body is satisfactorily located and deployed for example via a catheter delivery system, Main body (2) is inserted into Anchor body (1) and then the spherical section (207) is allowed to expand within Anchor body (1) as shown in
In use with a bifurcated vessel (310), as shown in
In use with a tortuous geometry (410) as shown in
In the application to vessels with side branches (510) as shown in
The application to bifurcated vessels (610) may require two or more main bodies (2) for treatment of two or more damaged vessels is shown in
In an alternate embodiment, an intermediate anchor body (7) is shown in
The foregoing description of the present invention describes an apparatus and method for excluding aneurysms occurring in the thoracic or abdominal aorta or for treating occlusive disease in the peripheral vasculature. It should be understood however, that the methods and apparatus of the present invention are equally applicable elsewhere in the human body where it is desired to repair a bifurcated vessel or organ, or to treat highly tortuous or angulated lumens. While preferred illustrative embodiments of the present invention are described above, it will be obvious to one skilled in the art that various changes and modifications may be made therein without departing from the invention and it is intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.
