Abstract:
An endovascular apparatus is provided for treating the effects of vascular disease including aneurysms and arterial blockages using a percutaneous, minimally invasive technique. In one embodiment the endovascular apparatus includes a tubular sleeve having a cranial end, a first caudal branch, and a second caudal branch such that the tubular sleeve is shaped like an upside down “Y.” The apparatus further includes at least one expandable attachment device attached to the tubular sleeve for securing the endovascular apparatus to an interior wall of a vessel. The at least one expandable attachment device includes a plurality of telescoping segments similar to the telescoping segments of a presentation pointer. Accordingly, during percutaneous insertion of the endovascular apparatus into a patient the attachment device can be collapsed into a small profile. Once positioned at the site of the aneurysm the telescoping attachment device can be expanded to hold the endovascular apparatus in place adjacent the inner lumen wall.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates generally to an endovascular apparatus for the treatment of aneurysms or arterial blockages, and more particularly, to an endovascular apparatus having an expandable attachment device for securing the endovascular apparatus to an interior wall of a lumen.  
         BACKGROUND  
         [0002]    An abdominal aortic aneurysm is an abnormal enlargement or “ballooning out” of the arterial wall of the aorta in a region that passes through the abdominal cavity, usually below the renal arteries and above the common iliac arteries. The aneurysm may also extend into the common iliac arteries. Such aneurysms are typically brought on by the weakening of the arterial wall from vascular disease. Although abdominal aortic aneurysms often do not cause pain, unless treated, an aneurysm may rupture causing a fatal hemorrhage in a patient.  
           [0003]    In the past aortic aneurysms were treated almost exclusively by surgical repair. Specifically, the aneurysm would be resected and replaced by an artificial artery known as a prosthetic graft. Because of the substantial risks associated with such an invasive surgery, however, other treatments for aortic aneurysms have been proposed including endovascular grafting.  
           [0004]    Endovascular grafting involves the placement of a prosthetic graft within the lumen of the artery such that the graft spans the length of the aneurysm. In this manner the aneurysm can be excluded from the circulatory system rather than resected. Using a catheter as a deployment device, the endovascular graft can be introduced into the vascular system percutaneously. Once the graft has been positioned at the site of the aneurysm it can be attached to the vascular wall both above and below the aneurysm using expandable attachment devices to prevent movement of the graft after deployment.  
           [0005]    To introduce an endovascular graft percutaneously, the graft must be collapsible into a small profile for negotiating the vascular system. Upon reaching the site of the aneurysm the graft and its attachment devices can be expanded into a desired shape using an inflating balloon catheter or other actuator. A variety of expandable attachment devices have been proposed for securing an endovascular graft to an interior wall of a vessel most of which use stents with hooks or barbs to penetrate the intima of the vessel. None of the proposed attachment devices, however, have been found to be ideally suited for use with an endovascular graft.  
           [0006]    Accordingly an endovascular apparatus having a new expandable attachment device is desired. The new attachment device ideally should be small with a low profile and should expand to many times its initial diameter. It also should exert enough radial force when expanded to fix into the aorta and thereby reduce blood leaks around the apparatus.  
         SUMMARY  
         [0007]    In a first aspect, an expandable attachment device for securing an endovascular apparatus to an interior wall of a lumen is provided. The expandable attachment device may include a plurality of telescoping arms that are joined together to form an expandable ring. This ring may function similarly to stents. The expandable attachment device may be attached to an endovascular apparatus for the treatment of aneurysms or blockages, such as a graft or stent, or to a heart valve and may include barbs, hooks, or other fasteners about its perimeter for attaching to the interior wall of a lumen. Because the attachment device can be collapsed to a size that can be fed through a vessel, the attachment device and an associated endovascular apparatus can be deployed percutaneously in a patient. Once positioned at the site of an aneurysm or arterial blockage, the telescoping attachment device can be expanded to hold the endovascular apparatus in place adjacent the inner lumen wall.  
           [0008]    In a second aspect, an endovascular apparatus is provided for treating aneurysms or arterial blockages using a minimally invasive technique. The apparatus includes a tubular sleeve having a cranial end and at least one caudal branch. If the tubular sleeve includes a first caudal branch and a second caudal branch then the tubular sleeve is shaped like an upside down “Y.” Accordingly, for the treatment of abdominal aortic aneurysms the cranial end may be positioned in the infrarenal aorta, the first caudal branch may be positioned in one of the common iliac arteries, and the second caudal branch may be positioned in the other common iliac artery. The tubular sleeve may be made from materials conventionally used to make endovascular grafts including synthetic fabrics or films, DACRON™, or expanded polytetrafluoroethylene (ePTFE) so as to define a lumen and so as to be collapsible during percutaneous insertion into a patient&#39;s vascular system.  
           [0009]    The endovascular apparatus further includes an expandable attachment device attached to the cranial end of the tubular sleeve for securing the apparatus to an interior wall of a vessel above an aneurysm. The expandable attachment device comprises a plurality of telescoping arms that are attached to form an expandable ring. Each telescoping arm is similar to an expandable presentation pointer. Alternatively, each telescoping arm may function like an accordion. Accordingly, during percutaneous insertion of the endovascular apparatus into a patient, the attachment device can be collapsed into a small profile. Once the apparatus is positioned at the site of the aneurysm or blockage, the expandable attachment device can be expanded to hold the endovascular apparatus in place adjacent the inner lumen wall. Fixation components may be positioned around the perimeter of the attachment device and may be partially embedded in the inner wall of the vessel to secure the attachment device.  
           [0010]    The plurality of telescoping arms may be made from materials suitable for use in the human body including stainless steel, plastic, or an alloy of nickel and titanium generally known as NITINOL™. NITINOL is commonly used in the manufacture of medical devices that are to be deployed in a compressed state through a catheter because of its unique thermal memory properties. For example, a NITINOL part may be manufactured in a first condition and then cooled and compressed into a second condition. When heated to the body temperature of the patient the NITINOL part will expand to its original first condition.  
           [0011]    In another aspect one or more expandable attachment devices may be attached to the one or more caudal branches of the tubular sleeve for securing the one or more caudal branches to the interior of the vessel wall.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a schematic illustration of an endovascular apparatus according to a first aspect;  
         [0013]    FIGS.  2 A-D show the endovascular apparatus of FIG. 1 in various states or expansion;  
         [0014]    [0014]FIG. 3 is a schematic illustration of an endovascular apparatus according to a second aspect;  
         [0015]    [0015]FIG. 4A is a top view of an expandable attachment device according to a first aspect in a fully collapsed state;  
         [0016]    [0016]FIG. 4B is a top view of the expandable attachment device of FIG. 4A in a partially expanded state;  
         [0017]    [0017]FIG. 4C is a top view of the expandable attachment device of FIG. 4A in a fully expanded stated;  
         [0018]    [0018]FIG. 5 is a locking mechanism according to a first aspect in a first position;  
         [0019]    [0019]FIG. 6 is the locking mechanism of FIG. 5 in a second position;  
         [0020]    [0020]FIG. 7 is a cross section of a segment of a telescoping arm according to a first aspect;  
         [0021]    [0021]FIG. 8 is an endovascular apparatus according to a third aspect;  
         [0022]    [0022]FIG. 9 is an endovascular apparatus according to a fourth aspect;  
         [0023]    [0023]FIG. 10 is an illustration of a typical abdominal aortic aneurysm located in the infrarenal aorta;  
         [0024]    [0024]FIG. 11 is a catheter for percutaneous introduction of an endovascular apparatus into a body lumen;  
         [0025]    [0025]FIG. 12A is a schematic top view of an expandable attachment device according to a second aspect in a partially expanded state;  
         [0026]    [0026]FIG. 12B is a schematic top view of the expandable attachment device of FIG. 12A in a fully expanded stated;  
         [0027]    [0027]FIG. 12C is a schematic side view of the expandable attachment device of FIG. 12A;  
         [0028]    [0028]FIG. 12D is a schematic side view of the expandable attachment device of FIG. 12B;  
         [0029]    FIGS.  13 A-G are schematic top views of an expandable attachment device according to a third aspect in various states of expansion;  
         [0030]    FIGS.  13 H-N are schematic side views of the expandable attachment device of FIGS.  13 A-G;  
         [0031]    FIGS.  13 O-U are schematic isometric views of the expandable attachment device of FIGS.  13 A-G;  
         [0032]    [0032]FIG. 14 is a schematic illustration of the endovascular apparatus of FIG. 1 having telescoping support columns;  
         [0033]    [0033]FIG. 15 is a schematic illustration of an endovascular apparatus according to another aspect;  
         [0034]    [0034]FIG. 16 is a schematic illustration of an expandable attachment device according to another aspect; and  
         [0035]    [0035]FIG. 17 is a schematic illustration of a telescoping catheter for percutaneous introduction of an endovascular apparatus into a body lumen. 
     
    
     DETAILED DESCRIPTION  
       [0036]    An endovascular apparatus  10  according to a first aspect is shown in FIG. 1. The endovascular apparatus  10  includes a tubular sleeve  12  having a cranial end  14 , a first caudal branch  16 , and a second caudal branch  18 . In other embodiments, termed “uni-iliac” devices, the tubular sleeve  12  may include only a single caudal branch. The tubular sleeve may be made from DACRON, ePTFE, peritoneum, fascia, or other common graft material so as to form a flow path for by-passing an aneurysm.  
         [0037]    The endovascular apparatus  10  further includes a first expandable attachment device  20  attached to the cranial end  14  of the tubular sleeve  12 , a second expandable attachment device  22  attached to the first caudal branch  16  of the tubular sleeve  12 , and a third expandable attachment device  24  attached to the second caudal branch  18  of the tubular sleeve  12 . The expandable attachment devices  20 ,  22 ,  24  may include holes  26  which may be sewn or sutured to the tubular sleeve  12 . Alternatively, in lieu of holes  26 , the expandable attachment devices can be woven into the sleeve.  
         [0038]    In another embodiment, the endovascular apparatus  10  may include a fourth expandable attachment device  28  that is attached to the first expandable attachment device  20  by support columns  30 . The fourth expandable attachment device  28  may be positioned above a patient&#39;s renal arteries, superior mesenteric artery or celiac artery. The support columns  30 , which may be made from NITINOL or stainless steel, may provide columnar support and strength for the endovascular apparatus  10  while permitting blood flow to arteries located between the first expandable attachment device  20  and the fourth expandable attachment device  28 .  
         [0039]    The support columns  30  may be either wires or tubes. If tubular, the support columns  30  may also be telescoping. For example, in another embodiment depicted in FIG. 14, the support columns  31  may comprise a plurality of incrementally sized segments that are slideably engaged and fit within one another. Thus, in this embodiment the endovascular apparatus  10  may be inserted percutaneously into a vessel with the support columns  31  contracted such that the axial distance between the first expandable attachment device  20  and the fourth expandable attachment device  28  is reduced. During deployment of the endovascular apparatus  10  the support columns  31  may be expanded, thereby permitting the first expandable attachment device  20  to be positioned below the renal arteries while the fourth expandable attachment device is positioned above the renal arteries. In yet another embodiment, shown in FIG. 14, the tubular support columns  30 ,  31 , whether telescoping or not telescoping, may contain an adhesive and include ports or apertures  33  such that the adhesive can escape the support columns  30 ,  31  upon deployment to assist in securing the endovascular apparatus  10  to the wall of a vessel.  
         [0040]    As illustrated in FIGS.  2 A- 2 D, the endovascular apparatus  10  is collapsible for easy insertion and navigation through a patient&#39;s vascular system using a catheter. Particularly, as illustrated in FIG. 2A, the attachment devices  20 ,  22 ,  24 , and  28  may be radially collapsed into a profile that is small enough to fit in a catheter sheath. When the attachment devices  20 ,  22 ,  24 ,  28  are deployed from the sheath at body temperature, the devices may be expanded by a balloon or other actuator to a size and shape in which they are able to retain the sleeve  12  against the wall of a vessel.  
         [0041]    The endovascular apparatus  10  according to a second aspect is shown FIG. 3 in which the tubular sleeve  12  is supported by support columns  32 . The support columns  32  may attach the first expandable attachment device  20  to a fifth expandable attachment device  34 . Likewise, the support columns  32  may attach the second and third expandable attachment devices  22 ,  24  to the fifth expandable attachment device  34  which may be located at the juncture of the first caudal branch  16  and the second caudal branch  18  of the tubular sleeve  12 . In addition the support columns  32  may be sewn or sutured to the exterior of the tubular sleeve  12 . This may provide continued columnar support throughout the endovascular apparatus  10  to prevent migration within the vessel. The support columns  32  may be telescoping as described with respect to FIG. 14.  
         [0042]    Referring to FIG. 4A, an expandable attachment device  20  according to a first aspect is shown in a fully collapsed state. The attachment device  20  includes a plurality of fixation components  36  positioned about the perimeter of the device  20 . A port  38  is located at the center of the attachment device  20 . The port  38  is sized so as to receive a balloon or other actuator during deployment. The balloon may be inflated to expand the attachment device  20  after insertion into a vessel. FIG. 4B shows the attachment device  20  in a partially expanded state. FIG. 4C shows the attachment device  20  in a fully expanded state.  
         [0043]    Referring to FIG. 4C, a telescoping arm  40  is used to attach each fixation component  36  to an adjacent fixation component  36 . The telescoping arm  40  may be pivotably attached to a fixation component  36  at one or both ends of the arm  40 . A telescoping arm  40  is made up of a plurality of segments  42 . The segments  42  may be in slideable contact with one another and may be incrementally sized so as to fit within one another. For example, each telescoping arm  40  may be constructed from what is referred to generally as “nested tubes.” When the telescoping arms  40  are fully extended the attachment device  20  may resemble a polygon having fixation components  36  located at its vertices. The fixation components  36  may include barbs or prongs  67  (shown in FIG. 8) for fixation to a vessel wall. In another embodiment shown in FIG. 16, the telescoping arms  40  may contain an adhesive and include ports or apertures  41  such that the adhesive can escape the telescoping arms upon deployment to assist in securing the endovascular apparatus  10  to the wall of a vessel.  
         [0044]    As one of ordinary skill might appreciate, the attachment device may take variety of shapes depending upon the configuration of the telescoping arms  40  and the fixation components  36 . For example, referring to FIGS.  12 A-D, the telescoping arms  40  may be positioned in a single plane. Alternatively, referring to FIGS.  13 A-U, the telescoping arms  40  may be positioned in multiple planes in, for example, what is referred to herein as an “M configuration.” One possible advantage of the M configuration is that it may produce superior radial force for holding the attachment device in position. In addition, the M configuration may produce the same ratio of expansion (i.e., the ratio of the final outer diameter of the attachment device in its expanded state to the initial outer diameter of the attachment device in its collapsed state) as the “single plane configuration” using fewer parts.  
         [0045]    To keep the telescoping arms  40  in their final extended state after deployment in a vessel, a one-way latch may be used to lock adjacent segments  42 . FIG. 5 shows one possible latch  44 , in a first position, for locking the telescoping arms  40 . The latch  44  may consist of a one or more grooves  46  associated with a first segment  48  and a tooth  50  associated with a second, adjacent segment  52 . As the telescoping arm  40  is expanded, the second segment  52  moves in a first direction A relative to the first segment  48 . The tooth  50  and the grooves  46  are aligned so as to engage when the telescoping arm  40  is extended. Once the tooth  50  engages a groove  46 , as shown in FIG. 6, the second segment  52  may not move in a second direction B relative to the first segment  48 . Accordingly, the telescoping arm  40  is free to extend but may not collapse once extended. Of course other one-way latches may be used to lock the segments  42  of the telescoping arms  40 . FIG. 7 illustrates one possible cross-section of a segment  42  of the telescoping arm  40 . This “rail” design permits room for sliding and positioning of a one-way latch, like the one shown in FIG. 5, between segments  42  shown in FIG. 4.  
         [0046]    [0046]FIG. 8 shows the endovascular apparatus  10  according to a third aspect. In the embodiment shown in FIG. 8, the endovascular apparatus  10  includes a double-expandable attachment device  60  in the place of the first expandable attachment device  20 . The double-expandable attachment device  60  comprises an upper expandable attachment device  62  and a lower expandable attachment device  64  which are separated by and attached to an o-ring seal  66 . The upper attachment device  62  is angularly offset from the lower attachment device  64  so that the fixation components  36  of each are offset. The fixation components  36  may include prongs or barbs  67  to aid in securing the expandable attachment devices  62 ,  64  to the vessel wall. This design provides for secure attachment to the vessel wall with reduced leakage around the perimeter of the attachment device  60 . The lower expandable attachment device  64  may be attached to the tubular sleeve  12 . The upper expandable attachment device  62  may be attached to the fourth expandable attachment device  28  by support columns  30 .  
         [0047]    Referring to FIG. 9, the endovascular apparatus  10  according to fourth aspect is shown. In this embodiment a plurality of “M springs”  68  are attached to the cranial end  14  of tubular sleeve  12  as graft expanders in order to hold the tubular sleeve  12  open. In this manner the M springs  68  may reduce leakage around the perimeter of the tubular sleeve  12 . M springs  68  may also be used to hold the caudal ends  16 ,  18  of the tubular sleeve  12  open. In the embodiment shown in FIG. 9, the M springs  68  are not attached to the segments  52  of the telescoping arms  40  and are located on the exterior of the tubular sleeve  12 . In another embodiment, the M springs  68  may be located on the interior of the tubular sleeve  12  or attached to the fixation components  36 . Of course, in place of the “M springs”  68 , springs in the shape of a “V” may be used. Alternatively, in another embodiment depicted in FIG. 15, the M springs  68  may be replaced by telescoping arms  40  in an “M configuration.” 
         [0048]    [0048]FIG. 10 illustrates a typical abdominal aortic aneurysm  70  located in the infrarenal aorta  71 . The infrarenal aorta  71  is that portion of the aorta  72  located below the renal arteries  74 ,  76 . As shown in FIG. 10, abdominal aortic aneurysms typically occur below the renal arteries  74 ,  76  and above the common iliac arteries  78 ,  80 . In some cases, the aneurysm includes the common iliac arteries  78 ,  80 . The endovascular apparatus  10  may be used to treat or repair an abdominal aortic aneurysm  70 , like the one shown in FIG. 10, by excluding the weakened aneurysmal aortic wall from pressurized and pulsatile flow. In addition, the endovascular apparatus  10  may be used to treat aneurysms or blockages located in other body lumens such as the thoracic aorta, iliac arteries, subclavian arteries, urinary tract, bile tract, intestinal tract, etc.  
         [0049]    The endovascular apparatus  10  may be deployed at the site of an aneurysm percutaneously using a catheter  82  like the one shown in FIG. 11. The catheter  82  may have an IV port  84 , a sheath  86  and an introducer  88  which can be withdrawn within the sheath  86 . Using the catheter  82 , the device can be introduced percutaneously through either of the femoral arteries. As shown in FIG. 17, using a “nested tube” design similar to the one utilized by the telescoping arms  40  of the attachment device  20 , the catheter  82  may also be made to be telescoping.  
         [0050]    During deployment the first expandable attachment device  20  may be positioned just below the renal arteries  74 ,  76  and seated with an expandable balloon or other actuator. The fourth expandable attachment device  28  may be positioned superior to the renal arteries  74 ,  76 , the mesenteric artery, or the celiac artery and seated with an expandable balloon. After the first attachment device  20  is seated, the second expandable attachment device  22  may be positioned in a first iliac artery  78  and seated with an expandable balloon or other actuator. The third expandable attachment device  24  may be positioned such that it rests at a second iliac artery  80 . To position and seat the third attachment device  24 , access may be obtained percutaneously through the second iliac artery  80 .