Abstract:
An endoluminal tubular prosthesis for use in an open surgical repair comprises a tubular graft having a longitudinal axis, a first tubular section having a plurality of self-expanding stents and extending along the longitudinal axis and a second stent-less tubular section extending from the first tubular section and along the longitudinal axis. The tubular prosthesis can include a plurality of tubular branching members branching therefrom for treating branched arteries without obstructing them, such as the branches from the aortic arch.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to grafts suitable for placement in a human body lumen such as an artery. 
       BACKGROUND OF THE INVENTION 
       [0002]    Tubular prostheses such as stents, grafts, and stent-grafts (e.g., stents having an inner and/or outer covering comprising graft material and which may be referred to as covered stents) have been used to treat abnormalities in passageways in the human body. In vascular applications, these devices often are used to replace or bypass occluded, diseased or damaged blood vessels such as stenotic or aneurysmal vessels. For example, it is well known to use stent-grafts, which comprise biocompatible graft material (e.g., polyester material such as Dacron® fabric, expanded polytetrafluoroethylene (ePTFE) or some other polymer) supported by a framework (e.g., one or more stent or stent-like structures) to treat vascular diseases such as aneurysms. The framework provides mechanical support and the graft material or liner provides a blood conduit. Approaches for making stent-grafts have included sewing one or more stents or annular metallic spring elements, which may have a sinusoidal configuration, to woven or laminated materials such as polyester material such as Dacron®, ePTFE, and other polymers. Many stent-grafts have a bare-spring or crown stent attached to one or both of its ends to enhance fixation between the stent-graft and the vessel where it is deployed. The bare-spring or crown stent can be referred to as an anchoring device. In treating an aneurysm, the graft material typically forms a blood impervious lumen to facilitate endovascular exclusion of the aneurysm. 
         [0003]    In open surgical treatment of a thoracic aortic aneurysm in the ascending aorta or the aortic arch, a surgeon performs a midline sternotomy to get access to the heart and ascending aorta. The surgeon will clamp the aorta to control bleeding, The surgeon will cut an opening in the ascending aorta proximal to the aortic arch to get access to the inside of the ascending aorta and suture a surgical graft into the aorta to exclude the aneurysm. This method of accessing the ascending aorta is also used to repair the aortic valve. When surgical repair of the aortic arch is required, a surgeon may use a graft to bypass or transpose the left common carotid artery, the left subclavian artery and the brachiocephalic artery so that blood can flow from and through the graft and to the patient&#39;s head and arms. The graft, may include a branching member that may be sewn to the left common carotid artery, the left subclavian artery and the brachiocephalic artery. 
         [0004]    When the patient&#39;s aneurysm extends from the aortic arch into the descending aorta. The surgeon will need to make another large incision on the side of the patient due to the lack of access through a the midline sternotomy 
         [0005]    Currently, there are stent grafts that can be used to treat thoracic aneurysms of the descending aorta. The stent graft is delivered to the thoracic aorta through a catheter that is introduced onto the vasculature from the femoral artery. The catheter deploys a stent graft inside the aorta and excluding the aneurysm. However these stent grafts can not be used to exclude an aneurysm in the arch without doing a surgical hybrid procedure. 
         [0006]    The hybrid procedure involves sewing a graft between to the brachiocephalic artery to the left carotid artery and left subclavian artery. Another stent graft is then introduced into the femoral artery deployed across the arch of the aorta starting just distal of the brachiocephalic artery. The stent-graft extends through (spans) the aneurysmal sac and beyond the proximal and distal ends thereof to replace or bypass the weakened portion of the vessel. 
         [0007]    There remains a need to develop alternative prostheses for treating aneurysms and methods of their placement. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention involves improvements in prostheses and/or methods for their placement. 
         [0009]    In one embodiment according to the invention, tubular prosthesis comprises a tubular graft having a longitudinal axis, a first tubular section extending along the longitudinal axis and a second stent-less tubular section being without annular stents, springs, or support members positioned about the longitudinal axis, the second tubular section extending from the first tubular section and along the longitudinal axis; and a plurality of self-expanding stents secured to the first tubular section, wherein the first tubular section forms a self-expanding stent-graft and the second tubular section forms a stent-less tubular graft. 
         [0010]    In another embodiment according to the invention, tubular prosthesis comprises a tubular graft having a longitudinal axis, a first tubular section extending along the longitudinal axis and a second tubular section extending from the first tubular section and along the longitudinal axis; and a plurality of self-expanding stents secured to the first tubular section, wherein the first tubular section forms a self-expanding stent-graft and the second tubular section forms a tubular graft that is not self-expanding. 
         [0011]    In another embodiment according to the invention, a tubular prosthesis comprises a tubular graft having a longitudinal axis, a first tubular section extending along the longitudinal axis and a second tubular section extending from the first tubular section and along the longitudinal axis, the first tubular section having a length of at least 50 mm and being without an annular support member; and a plurality of stents secured to the first tubular section, wherein the first tubular section forms a self-expanding stent-graft and the second tubular section forms a tubular graft that is not self-expanding. 
         [0012]    In another embodiment according to the invention, tubular prosthesis comprises a tubular graft having a longitudinal axis, a first tubular section and a second tubular section and a plurality of tubular branching members, the first tubular section extending along the longitudinal axis and the second tubular section extending from the first tubular section and along the longitudinal axis, the first tubular section including a plurality of stents secured thereto, the second tubular section being without an annular support member, each of the plurality of tubular branching members including at least one stent secured thereto, and the plurality of tubular branching members branching from the second tubular section an being in fluid communication therewith. 
         [0013]    In another embodiment according to the invention, tubular prosthesis apparatus comprises a tubular graft having a longitudinal axis, a first tubular section, and a second tubular section, the first tubular section extending along the longitudinal axis and the second tubular section extending from the first tubular section and along the longitudinal axis, the first tubular section having a first configuration and a second radially compressed configuration, the second tubular section forming a lumen; a plurality of tubular branching members branching from the second tubular section, each of the branching members having a first configuration and a second radially compressed configuration, each branching member forming a lumen that is in fluid communication with the lumen formed by the second tubular section; and a plurality of sleeves, each one of the sleeves surrounding one of the first tubular section and plurality of tubular branching members and restraining the first tubular section and the plurality of tubular branching members in the radially compressed configurations. 
         [0014]    In another embodiment according to the invention, a method of treating an aneurysm comprises advancing a tubular prosthesis having a restrained first self-expanding tubular section with a plurality of stents and a second tubular stent-less section with the first tubular section in a radially compressed state through a vessel to an unexposed vessel location where the first tubular section spans a target site; unrestraining the first tubular section to allow the first tubular section to radially expand; and securing the second tubular stent-less section of the tubular prosthesis to the vessel at a location where the vessel has been exposed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1A  illustrates one embodiment of a prosthesis according to the invention. 
           [0016]      FIG. 1B  illustrates the embodiment illustrated in  FIG. 1A  in a delivery state with a plurality of deployment mechanisms each having a restraints restraining a portion of the prosthesis in a radially compressed or reduced diameter configuration as compared to the uncompressed configuration shown in  FIG. 1A . 
           [0017]      FIG. 1C  illustrates the bare frame of the core catheter shaft elements of the plurality of deployment mechanisms shown in  FIGS. 1A and 1B  each having hook like prosthesis tip capture elements configured to hold a end portion of the stent graft prosthesis at the end of the shaft of the implanting catheter away from the implanting physician extended in tension and fixed to the end of the respective shaft as its respective sheath is retracted. 
           [0018]      FIG. 2A  is a longitudinal partial sectional view of one restraint mechanism loaded with a section of the prosthesis of  FIG. 1A . 
           [0019]      FIG. 2B  is an end view of the apparatus of  FIG. 2A  taken along line  2 B- 2 B. 
           [0020]      FIG. 2C  diagrammatically shows partial deployment of a section of the prosthesis shown in  FIG. 2A  depicting splitting and withdrawal of the restraint, which is in the form of a sleeve. 
           [0021]      FIG. 2D  diagrammatically shows further deployment of the section of the prosthesis being deployed in  FIG. 2C . 
           [0022]      FIGS. 3A-E  diagrammatically illustrates one method of using the prosthesis shown in  FIGS. 2A and 2B , where  FIG. 3A  diagrammatically illustrates the physician&#39;s view once a midline sternotomy has been performed to expose the heart and its aortic arch,  FIG. 3B  diagrammatically illustrates a side view of the aorta (the descending aorta generally not being visible in the midline sternotomy) and an incision formed in the ascending aorta and the aortic arch,  FIG. 3C  diagrammatically illustrates the prosthesis of  FIG. 1A  with restraints as shown in  FIG. 2B  after one end of the device has been introduced through the ascending aorta incision, through the aortic arch and into the descending aorta,  FIG. 3D  diagrammatically illustrates partial deployment of one section of the prosthesis, and  FIG. 3E  diagrammatically illustrates the prosthesis fully deployed. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    The following description will be made with reference to the drawings where when referring to the various figures, it should be understood that like numerals or characters indicate like elements. 
         [0024]    In one embodiment according to the invention, a tubular prosthesis comprises a tubular graft having a longitudinal axis, a first tubular section having a plurality of self-expanding stents and extending along the longitudinal axis and a second stent-less tubular section extending from the first tubular section and along the longitudinal axis. With this configuration, an antegrade approach can be used to treat an aneurysm (e.g., a thoracic aortic aneurysm that extends along the descending aorta) where a physician advances the first tubular section through an opening in an exposed vessel (e.g., an opening formed in the ascending aorta after a midline sternotomy) while the first tubular section is in a radially compressed state, and through the vessel to an unexposed vessel location (e.g., the descending aorta after a midline sternotomy) where it spans a target site where the first tubular section is allowed to expand and the second tubular section sewn to the vessel at a location where the vessel has been exposed (e.g., along the ascending aorta that has been exposed during a midline sternotomy). Other advantages will become apparent from the following description. 
         [0025]    Referring to  FIG. 1A , one prosthesis embodiment according to the invention is shown and generally indicated with reference numeral  100 . Prosthesis  100  includes a tubular graft (member)  102  having a longitudinal axis “A” and first and second tubular sections  104  and  106 . First tubular section  104  includes a plurality of stents and second tubular section  106  has no stents. In other words, first tubular section  104  forms or corresponds to a stent-graft or covered stent and second tubular section  106  forms or corresponds to a stent-less tubular graft. In the embodiment illustrated in  FIG. 1A , second tubular section  106  is without any annular support such as an annular stent or an annular spring such as a sealing spring. Tubular graft  102  can be made from any suitable material such as polyester, PTFE, ePTFE, UHMWPE, PET, Kevlar® fiber, Dacron® fabric, or PEEK material. First tubular section  104  of tubular graft  102  has secured thereto stents  108   a ,  108   b ,  108   c ,  108   d ,  108   e ,  108   f , and  108   g  which are secured to the graft using any known techniques such as suturing. However, more or fewer stents can be used depending on the application and desired length of section  104 . First tubular section  104  also can provided with a sealing spring, such as sealing spring  110 , which similarly can be sutured to the tubular graft. A bare spring such as bare spring  112 , which can be referred to as a crown stent and which assists in anchoring the prosthesis in a vessel, also is optional and can be secured to first tubular section  104  adjacent to sealing spring  110 . The stents, sealing spring, and bare spring are annular members that have undulating configurations and can be formed from nitinol or any other suitable material. 
         [0026]    First tubular section  104  of tubular graft  102  has an exposed first end  104   a  and a blind second end  104   b . Second tubular section  106  of tubular graft  102  similarly has an exposed first end  106   a  and a blind second end  106   b . Sections  104  and  106  can be integrally formed from a single piece of graft material or separately formed and secured to one another at blind ends  104   b  and  106   b  using any known technique such as suturing or they can be interwoven. For example, first tubular section  104  can be constructed as a stent-graft (or covered stent) and then secured to tubular graft section  106 , which in the illustrative embodiment is without any annular support structure such as an annular stent or an annular spring such as a sealing spring. 
         [0027]    Prosthesis  100  also includes three tubular branch or branching members, which in the illustrative embodiment correspond to stent-grafts (or covered stents)  120 ,  130 , and  130 , branching from second tubular section  106 . Tubular member  102  forms a lumen and each branch member or stent-graft  120 ,  130 , and  130  forms a lumen that is in fluid communication with the lumen formed by tubular member  102 . Stent-graft  120  includes a tubular graft  122 , annular undulating stents  124   a ,  124   b , and  124   c  secured (e.g., stitched) thereto, sealing spring  126  secured (e.g., stitched) thereto, and bare spring (or crown stent)  128  secured (e.g., stitched) thereto. Stent-graft  130  includes a tubular graft  132 , annular undulating stents  134   a ,  134   b , and  134   c  secured (e.g., stitched) thereto, sealing spring  136  secured (e.g., stitched) thereto, and bare spring (or crown stent)  138  secured (e.g., stitched) thereto. Stent-graft  140  includes a tubular graft  142 , annular undulating stents  144   a ,  144   b , and  144   c  secured (e.g., stitched) thereto, sealing spring  146  secured (e.g., stitched) thereto, and bare spring (or crown stent)  148  secured (e.g., stitched) thereto. Stent-grafts  120 ,  130 , and  140  can be stitched or sutured to second tubular section  106  of tubular member  102 . Although three branching members are shown secured to second tubular section  106  of tubular member  102 , fewer branching members may be used depending on the application (e.g., the prosthesis can include one or no branching members). 
         [0028]    The dimensions of the prosthesis will depend on the application. When used in antegrade deployment from the ascending aorta to the descending aorta during open heart surgery, second tubular section  106  will have a length “L 2 ” measured along longitudinal axis “A” of at least 50 mm, which corresponds to the minimal length of the aortic arch plus an additional length to cut from outside the aorta after the first tubular section is deployed and trimmed after first end  106   a  of second tubular section  106  or a section adjacent thereto has been sutured to the ascending aorta. In this application, first tubular section  104  typically will have a length “L 1 ” measured along longitudinal axis “A” of 100 mm to about 500 mm and typically will be about 200 mm. The stent-graft branching members are configured for placement in the brachiocephalic artery, left common carotid artery, and left subclavian artery and typically will have a length from about 20 mm to about 80 mm. In another example, the prosthesis is placed to treat an aneurysm or stenosis in the _superficial femoral artery _. In this example, prosthesis  100  has no branching members. A cut is made at the groin of the patient down to the femoral artery, the femoral artery is clamped, and an incision made in the femoral artery. The prosthesis is introduced into the femoral artery, advanced down the entire superficial femoral artery to the popliteal artery. In other words, the prosthesis is placed from the hip to the knee of the patient. The first tubular section restraint is released to allow the first tubular section to expand and the second tubular section, which typically will be without any annular support such as an annular stent or an annular spring such as a sealing spring, is cut outside the femoral artery, sutured to the femoral artery near the groin, and trimmed. In this application, second tubular section  106  will have a length “L 2 ” measured along the longitudinal axis “A” of least 100 mm and up to about 1,000 mm. First tubular section  104  of tubular graft  102  (the section having stents) will have a length “L 1 ” measured along the longitudinal axis “A” of at least 30 mm, which typically corresponds to a stent-graft having two or three stents. 
         [0029]    Referring to  FIG. 1B , prosthesis  100  is shown in a delivery state with first tubular section  104  and branching members  120 ,  130 , and  140  radially compressed and restrained in deployment mechanisms or devices  200 ,  300 ,  400 , and  500 . In this embodiment, each of first tubular section  104  and branching members  120 ,  130 , and  140  is a self-expanding stent-grafts. Each deployment mechanism or device includes a restraint, which in the illustrative embodiment is in the form of a tubular splittable sleeve  202 ,  302 ,  402 , and  502 , to restrain a portion of the prosthesis in a radially compressed or reduced diameter configuration for advancement through a vessel or endolumenal advancement. More specifically, splittable sleeves  202 ,  302 ,  402 , and  502  restrain stent-grafts (or covered stents)  104 ,  120 ,  130 , and  140  in a radially compressed state about distal end portions of inner tubes  208 ,  308 ,  408 , and  508 . 
         [0030]    Referring to  FIG. 1C , only the core elements of the delivery catheter elements are shown picturing the end stent capture fingers  209 ,  309 ,  409 ,  509 . These fingers function to prevent the prosthesis section contained in the respective surrounding sleeve from moving back with the surrounding sleeve, as it is split and retracted. These fingers assure the fully extension of the graft material and stent graft element in its respective surrounding lumen. 
         [0031]    Referring to  FIG. 2A , deployment mechanism or device  200  is shown in partial section. Since deployment mechanisms  200 ,  300 ,  400 , and  500  all have the same construction, only deployment mechanism  200  will be described in detail. Deployment mechanism  200  includes outer splittable restraint or sleeve  202  having annular hub portion  204  extending therefrom tabs  206   a  and  206   b  extending radially from hub portion  204  all of which can be integrally formed as a single piece construction. Annular hub portion  204  has reduced thickness sections  204   a  and  204   b  that extend the full extent of hub portion  204  in the longitudinal direction. Sleeve  202  and sleeve hub portion and  206  are relatively soft plastic material such as polyethylene. so that when tabs  206   a  and  206   b  are pulled apart, the reduced sections split and the diametrically opposed splits formed in sleeve  202  continue to run along sleeve  202  as one continues to pull the tabs. An inner tube  208  is disposed inside sleeve  202  through which optional guidewire  600  can be slidably disposed. Integrally formed with tube  208  is tapered tip  210  and attached thereto are retaining fingers  209 , one finger to engage each crown of an end stent of the prosthesis section to be deployed. First portion  104  of tubular member  102  is radially compressed and inserted over tube  208  with the end stent&#39;s crowns being engaged and captured by the retaining fingers  209 . The first portion  104  is positioned between tube  208  and sleeve  202 . Tube  208  is sufficiently long so that a physician or operator can hold tube  208  which in turn transmits a compressive force to retaining fingers  209 ′ while tabs  206   a  and  206   b  are pulled apart in a radial direction to maintain tube  208  stationary so that the sleeve will split and retract.  FIGS. 2C and 2D  are illustrative of how the sleeve is split to deploy section  104 . Referring to  FIG. 2C , the physician or operator holds tube  208  stationary. Another physician or operator can pull tabs  206   a  and  206   b  to simultaneously spit and retract sleeve  202  so that first tubular section  104  begins to deploy as shown in  FIG. 2C . As the tabs are further pulled, the sleeve is further withdrawn as shown in  FIG. 2D  until the sleeve is fully split and first tubular section fully deployed (see  FIG. 3E ). 
         [0032]    Referring to  FIGS. 3A-E , one method of using prosthesis  100  is diagrammatically shown.  FIG. 3A  diagrammatically illustrates a midline sternotomy where a patient&#39;s heart  10  and a portion of aorta  20  is shown. Generally speaking, the portion of the aorta distal to the left subclavian artery (i.e., the descending aorta) is not visible or accessible for surgery from the outside thereof without turning the patient on the patient&#39;s side and cracking ribs on a side of the patient and cutting down to the descending aorta.  FIG. 3B  diagrammatically illustrates a side view of aorta  20 , which extends from aortic root  22  and includes ascending aorta  24 , aortic arch  26 , and descending aorta  28 , to show how prosthesis  100  will be introduced into the descending aorta to bypass an aneurysm “A,” which extends from an area proximal to the aortic arch to the region of the aorta distal to the left subclavian artery  50 . The physician makes an incision  24   i  in ascending aorta  24  for introduction of the prosthesis into the aorta and longitudinal incision  26   i  in aortic arch  26 , which can be flapped back so that the physician can insert the prosthesis branching members into branch arteries  30  (brachiocephalic),  40  (left common carotid), and  50  (left subclavian) and manipulate tabs  206   a  and  206   b  as will be described in more detail below.  FIG. 3C  diagrammatically illustrates prosthesis  100  in its delivery state as described above with reference to  FIG. 1B  and after it has been introduced through incision  24   i  with first tubular section  104 , which is in deployment mechanism or device  200 , positioned in descending aorta  28 , and branching stent-grafts  120 ,  130 , and  140 , which are in deployment mechanisms or devices  300 ,  400 , and  500 , positioned in brachiocephalic artery  30 , left common carotid artery  40 , and left subclavian artery  50 . If optional guidewire  600  is used, it placed through incision  24   i  and into the descending aorta and then prosthesis  100  is tracked over the guidewire. Referring to  FIG. 3D , tube  208  is held so that it and the portion of the prosthesis contained therein to be deployed is axially restrained and tabs  206   a  and  206   b  pulled to split and retract sleeve  202 . After sleeve  202  is fully split into two separate pieces and stent-graft section  104  fully deployed, sleeve  202 , guidewire  600 , and tube  208  are removed. Then sleeves  302 ,  402 , and  502  are split and retracted in the same manner to release branching stent-grafts  120 ,  130 , and  140 . Sleeves  302 ,  402 , and  502  and tubes  308 ,  408 , and  508  are removed. The proximal end of tubular graft  102 , which is the end closest to the heart, is sutured to the aorta as depicted with line “S” and the incisions sutured closed as shown in  FIG. 3E . Incisions  24   i  and  26   i  are sutured closed as indicated with reference numerals  24   s  and  26   s.    
         [0033]    Any feature described in any one embodiment described herein can be combined with any other feature or features of any of the other embodiments or features described herein. Furthermore, variations and modifications of the devices and methods disclosed herein will be readily apparent to persons skilled in the art.