Patent Publication Number: US-2022211483-A1

Title: Endovascular stent-graft with an extravascular extension

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/064,320, filed Aug. 11, 2020, the contents of which are hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention generally relates to medical devices, and more particularly to an endovascular stent-graft with an extravascular extension and a method of providing an endovascular stent-graft with an extravascular extension to a patient. 
     Discussion of the Background 
     There are a variety of surgical procedures, such as those that require access to the aorta, or vena cava, which requires a surgeon to access these blood vessels through the abdomen or the chest. Thus, for example, coronary bypass surgery, in which blood flow is redirected around a section of a blocked or partially blocked artery, is performed by making a long incision in the chest, cutting the center of the chest along the breastbone, spreading the rib cage open to expose the heart, and inserting a healthy blood vessel, often from inside the chest wall or from the lower leg by attaching the ends above and below the blocked artery so that blood flow is redirected around the narrowed part of the diseased artery. Such procedures are highly invasive. 
     On the other hand, there are several procedures that access the heart, but which are much less invasive, such as coronary stent placement. This procedure is performed with a stent delivery apparatus in which a compressed, self-expanding stent is placed in the tip at a distal end of a delivery system. The tip is then inserted into an artery in the groin, arm or wrist area and is directed through the artery and towards the heart. Once the tip reaches the required location, the delivery system is actuated, releasing the compressed stent in the artery, which then expands to sit against the inner walls of the artery near the heart, and the delivery system is removed. 
     Unfortunately, devices used for such non-invasive procedures are not useful for preforming more complicated procedures, such as coronary bypass surgery. 
     There is a need in the art for less invasive surgical procedures and for medical devices that support such procedures. In addition, to coronary bypass procedures, such devices should also be useful in procedures that involve other large blood vessels, such as the vena cava, iliac, or common femoral artery. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention overcomes the disadvantages of prior art by providing an endovascular stent-graft having an extravascular extension, also referred to herein, without limitation, as an “stent-graft with branching graft.” 
     It is one aspect of certain embodiments to provide a stent-graft with branching graft including: a stent-graft having a first end, a second end, and an aperture through the stent-graft between the first end and the second end, and a vascular graft having a first end and a second end, where the first end of the vascular graft extends from the aperture of the stent-graft, where a lumen of the stent-graft with branching graft includes a lumen of the sent-graft and a lumen of the vascular graft. 
     It is another aspect of certain embodiments to provide a method of using a stent-graft with branching graft to perform a medical procedure, where the stent-graft with branching graft includes a stent-graft having a first end, a second end, and an aperture through the stent-graft between the first end and the second end, and a vascular graft having a first end and a second end, where the first end of the vascular graft extends from the aperture of the stent-graft, and where a lumen of the stent-graft with branching graft includes a lumen of the sent-graft and a lumen of the vascular graft. The method includes: incising the skin of the patient to form an incision; puncturing the target vessel of the patient with a needle; providing the stent-graft through the incision, through the puncture of the target vessel, and into the lumen of the target vessel; and expanding the stent-graft such that the stent-graft contacts an inner surface of the target vessel, such that the stent-graft is within the target vessel and such that the vascular graft extends out of the target vessel through the puncture. 
     In certain embodiments, the method provides access to the circulatory system of the patient through the vascular graft, and providers for performing medical procedures on the circulatory system. 
     In certain other embodiments, the target vessel is a vena cava of the patient, and the method provides a graft for performing hemodialysis. 
     These features together with the various ancillary provisions and features which will become apparent to those skilled in the art from the following detailed description, are attained by the endovascular stent-graft with an extravascular extension and method of the present invention, preferred embodiments thereof being shown with reference to the accompanying drawings, by way of example only, wherein: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a side view of a first embodiment endovascular stent-graft; 
         FIG. 2  is a sectional top view  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a side view of a portion of a second embodiment endovascular stent-graft; 
         FIG. 4  is a sectional top view  3 - 3  of  FIG. 3 ; 
         FIGS. 5A and 5B  are a first and second side view, respectively, illustrating the placement of the second embodiment endovascular stent-graft in a target vessel; and 
         FIG. 6  illustrates one use of the endovascular stent-graft. 
     
    
    
     Reference symbols are used in the Figures to indicate certain components, aspects or features shown therein, with reference symbols common to more than one Figure indicating like components, aspects or features shown therein. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description includes the disclosure of an endovascular stent-graft and several minimally invasive interventions enabled by the endovascular stent-graft. In general, as described subsequently, the endovascular stent-graft includes a stent-graft and a vascular graft that branches from the stent-graft and forms an extravascular extension. The endovascular stent-graft with an extravascular extension may be inserted into the body near, for example, the aorta, iliac, or femoral areas, and through an incision in a target vessel, such as an artery or vein, and with the graft extending through the incision to the outside of the target vessel. The graft then provides access to the circulatory system. 
       FIG. 1  is a side view of a first embodiment endovascular stent-graft  100  and  FIG. 2  is a sectional top view  2 - 2  of  FIG. 1 . Endovascular stent-graft  100  includes a stent-graft  110  and a branching vascular graft  120 . 
     Stent-graft  110  has an outer surface  115  and an inner surface  117  and includes a stent  113 , which is a metal framework or mesh, covered by a graft  111 , which is a thin fabric formed from a polyester, such as expanded polytetrafluoroethylene (ePTFE). Stent  113  of stent-graft  110  is a collapsible and self-expanding structure formed from a metal alloy such as nickel titanium, which also known as nitinol, and graft  111  of the stent-graft is a barrier to the flow fluids, such as blood. 
     The expanded shape of stent-graft  110  is generally cylindrical, with a centerline A, a diameter Ds, and a length, Xs, between a first end  112  and a second end  114 , and a lumen Vs. Stent-graft  110  differs from commercially available stent-grafts in that it includes an aperture  116 . As discussed subsequently, the shape of aperture  116  matches that vascular graft  120 . In certain embodiments, aperture  116  is located midway between first end  112  and second end  114 , as shown in the Figures. In certain other embodiments, aperture  116  is closer to one of first end  112  or second end  114 . 
     Vascular graft  120  has an outer surface  121  and an inner surface  123 , and is generally cylindrical and extends from a first end  122  to a second end  124 . The material of vascular graft  120  may, for example and without limitation, be ePTFE. Vascular graft  120  is generally cylindrical in shape, with a centerline B, diameter Dg, and a length, Lg, between first end  122  and second end  124 , and a lumen V G . 
     First end  112  of vascular graft  120  extends from aperture  116 , such that a lumen of the endovascular stent-graft  100  includes a lumen of the stent-graft  110  and a lumen of the vascular graft  120 . In one embodiment, first end  116  is joined to aperture  116  of stent-graft  110  by a suture  121 , by which may be a conventional medical suture. In other embodiments, stent-graft  110  and branching vascular graft  120  are joined by bonding, such a by an adhesive, or are formed as a single piece in the manufacturing process. 
     In certain embodiments, it is preferred that the portion of sent-graft  110  near aperture  116  includes a sufficient amount of stent  113  material so as to provide an outwards radial force so that the stent-graft maintains the circular shape of the aperture. 
     In certain embodiments, the diameter of stent-graft  110 , Ds, is from 1 to 5 cm, the length of the stent-graft, Ls, is from 15 to 40 cm. Typically, the diameter Ds is selected to be slightly larger that the target vessel into which is to be inserted. The diameter of vascular graft  120 , Dg, is from 5 to 10 cm, and the length of vascular graft  120 , Lg, is from 3 to 70 cm. 
     By way of example, a commercially available stent-graft which is similar to stent-graft  110  is, without limitation, a GORE® VIABAHN® VBX Balloon Expandable Endoprosthesis (see https://www.goremedical.com/products/vbx), manufactured by W. L. Gore &amp; Associates, Inc. (Newark, Del.). Further, by way of example, a commercially available grafts which is similar to vascular graft  120  is, without limitation, a GORE-TEX® Stretch Vascular Graft (see https://www.goremedical.com/products/vgstretch), manufactured by W. L. Gore &amp; Associates, Inc. (Newark, Del.). 
       FIG. 3  is a detailed side view of a second embodiment endovascular stent-graft  300  and  FIG. 4  is a sectional top view  4 - 4  of  FIG. 3 . Endovascular stent-graft  300  is generally similar to endovascular stent-graft  100 , except as explicitly noted. 
     Endovascular stent-graft  300  includes stent-graft  110  and graft  120 , as discussed above, and also includes a sealing assembly  310  including a first portion  311  attached to inner surface  115  of graft  111 , a second portion  313  attached to outer surface  123  of vascular graft  120 , a balloon  315 , and a tube  317  in fluid communication with the balloon and which is used for inflating/deflating the balloon. An end of tube  317  that is not attached to balloon  315  may be attached to a pump and/or a sealing mechanism to maintain inflation of the balloon. First portion  311  and inner surface  115 , and second portion  313  and outer surface  123  are attached, for example and without limitation, with suture  122 . Alternative, one or both of these attachments may be manufactured as one piece. Balloon  315  may be inflated using tube  317  to force the balloon is against graft  111 . 
     Endovascular stent-graft  100  or  300  may be used for any one of a number of procedures the require access to the circulatory system including, but not limited to, bypassing the aorta, bypassing the distal iliac-femoral-popliteal bypass, providing dialysis grafts, and providing access to the heart for certain medical procedures. 
     The first steps of using endovascular stent-graft  100  and  300  is to deliver stent-graft  110  of the endovascular stent-graft into the target vessel. Stent-graft  110  is generally similar to conventional stent-grafts, and may utilize conventional stent-graft delivery systems. One example of a stent-graft delivery system is, without limitation, a Valiant Thoracic Stent-graft with the Captivia Delivery System (https://www.medtronic.com/us-en/healthcare-professionals/products/cardiovascular/aortic-stent-grafts/valiant-thoracic-stent-graft-with-captivia-delivery-system.html), manufactured by Medtronic (Fridley, Minn.). 
     Thus, for example, stent-graft  110  is compressed and provided into the tip of the delivery system (not shown). Next, a surgeon makes an incision of the patient&#39;s body, directs a need to the location in the target vessel where the endovascular stent-graft  100  or  300  is to be delivered, and punctures the target vessel with the needle. In certain embodiments, the patient is placed on their abdomen and the first incision is made through the patient&#39;s back using a trans-lumbar approach. 
     Next, the surgeon inserts a guide wire through the needle and into the target vessel, and then removes needle leaving the guide wire in place. 
     Next, the dilator and sheath are passed together, over the guide wire, and into the blood vessel, where the tapered tip of the dilator acts to stretch the opening in the blood vessel to allow for the insertion of the larger sheath. The dilator is then removed, leaving only the sheath and guide wire in blood vessel, where the sheath provides a port into the blood vessel. 
     Next, the surgeon guides the tip of the delivery system, with or without the aid of a computerized tomography (CT) scan, through the sheath and into the target vessel. With the compressed stent-graft  110  inside the target vessel, and with vascular graft  120 , and optionally tube  307 , extending outside of the target vessel, the surgeon operates the delivery system to release stent-graft  110 , and then removes the delivery system from the patient. 
     Placing endovascular stent-graft with an extravascular extension  300  requires an extra step, as illustrated for example in  FIGS. 5A and 5B , which are a first and second side view, respectively, illustrating the placement of the endovascular stent-graft  300  in a target vessel, V. 
       FIG. 5A  illustrates the initial placement of endovascular stent-graft with an extravascular extension  300  in a target blood vessel, V, having a tunica intima, TI, and a tunica externa, TE. The expanded stent-graft  110  contacts tunica intima, TI with vascular graft  120  extending though a puncture P of target vessel, V. This figure also illustrates the placement of an expanded endovascular stent-graft with an extravascular extension  100  in target vessel, V. 
     In a next step,  FIG. 5B  illustrates the use of tube  317  to inflate balloon  315 . A portion of balloon  315  expands towards and provides a force against tunica externa, TE, compressing target vessel, V, between the balloon and stent-graft  110 . The resulting compression force acts to secure endovascular stent-graft  300  to the target vessel, V, and reduce the likelihood of a leak of blood from the target vessel. 
     Once stent-graft  110  of endovascular stent-graft  100  or  300  is released from the delivery system, the stent-graft expands and seats against the inner surface of target vessel. At this time, endovascular stent-graft  100  or  300  is in place, and vascular graft  120  is either attached to a second target vessel or uses the graft to access the circulatory system, as described subsequently. 
     Several specific uses of endovascular stent-graft with an extravascular extension  100  or  300  are now presented. These uses are illustrative and are not meant to limit the scope of the present invention. The first steps are those discussed above, which describe the placement of the endovascular stent-graft with an extravascular extension in the target vessel. If length Lg of vascular graft  120  is not sufficient for the intended use of endovascular stent-graft with an extravascular extension  100  or  300 . then an additional length of graft may be sutured to end  124 , effectively increasing the length of lumen of the vascular graft. 
     A first use of endovascular stent-graft with an extravascular extension  100  or  300  is to allow external access to the heart, for example, to perform a heart valve repair procedure, as illustrated in  FIG. 6 , which illustrates the use of the method on a patient P have a back B and an artery (for example aorta or vena cava).  FIG. 6  also shows the location of a site of an incision, I, in the patient&#39;s back and the puncture, P, in the target vessel V. Once endovascular stent-graft with an extravascular extension  100  or  300  is in place in target vessel V, the second end  124  of vascular graft  120  is left open and external to the patient. The surgeon then inserts devices for providing minimally invasive surgery, as are known in the art, into send end  124 , through the aorta or vein, and to the heart. Once the heart valve is repaired and the device for effecting the repair are removed from endovascular stent-graft  100  or  300 , vascular graft  120  is tied off and incision I is sutured. This method has the advantage over the prior art in that the surgeon minimally invasively enters the patent through their back. 
     A second use of endovascular stent-graft  100  or  300  is for a aortobifemoral bypass. For this use, the target vessel is an artery, and the second end  124  of vascular graft  120  is attached elsewhere in the circulatory system of the patient, such as the leg, to provide a bypass. Once endovascular stent-graft  100  or  300  is thus placed, incision I is sutured. This method has the advantage over the prior art, where the surgeon accesses the target vessel though the abdomen, in that the surgeon minimally invasively enters the patient through their back. 
     A third use of endovascular stent-graft  100  or  300  is for hemodialysis. For this use, the target vessel is the vena cava the second end  124  of vascular graft  120  is attached, under the skin, to the femoral artery. Once endovascular stent-graft  100  or  300  is thus placed, incision I is sutured. Dialysis is then provided using vascular graft  120 . which is located under the skin. 
     A fourth use of endovascular stent-graft  100  or  300  is to provide access to the aorta for any intra-aortic procedure when the lower part of the aorta is blocked. 
     A fifth use of endovascular stent-graft  100  or  300  is to bypass blockages in the iliac or femoral arteries to the popliteal artery. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments. 
     Similarly, it should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.