KR20030036687A - Distally narrowed vascular grafts - Google Patents

Abstract

The graft 10 of the present invention has a first end 20 adapted for insertion into a blood vessel site for transfusion and a second end 30 adapted for attachment to an arterial site. The graft 10 is preferably made of a material having a generally uniform thickness, and the graft 10 defines a lumen 11 having the same shape as the outer surface of the graft 10. In the graft 10, the distal end 20 defines an orifice 21 and the proximal end 30 defines an orifice 31. The portion of lumen 11 defined by zone 23, also referred to as the “stepped” or “taper” zone, generally decreases gradually from the longitudinally adjacent zone 40. Have a diameter.

Description

Distally narrowed vascular grafts with narrow distal

As a background for vascular grafts used to construct arterial-to-venous connections, over 40,000 new patients are reported to undergo hemodialysis each year. These figures continue to increase at an annual rate of approximately 10%. It is also estimated that doctor and hospital spending in 1998 for initiation and maintenance of hemodialysis approaches amounted to approximately $ 8 million. The term “access” is considered to be the same as the location within the patient's circulatory system specifically configured to serve as a site for supplying blood to the dialysis machine and receiving blood recovered from the dialysis machine. If the patient's condition is acceptable, the preferred approach is to use a graft or fistula, which can be inserted repeatedly to deliver blood to and from the dialyzer during dialysis treatment. A subcutaneous device in fluid communication with a patient's circulatory system.

The most common cause of dialysis patients in hospitals is access-related problems, and obstacles and costs of access failures will continue to increase until solutions to current access-related problems are identified and implemented. Despite this obvious need, progress has been made in the field of hemodialysis approaches over the last three decades. Hamkin and Himmelfarb, in a paper entitled "Hemodialysis Access Failure: A Call to Action", "When it comes to the hemodialysis approach, we can't do the same thing anymore, and ... [our end-stage renal disease] (end stage renal disease)] It is expected that the patient's life will be enhanced or the cost of access treatment will be reduced. ” Hamkin R, Himmelfarb J. Hemodialysis Access Failure: A Call to Action , Kidney International Vol. 54 (1998), pp. 1029-1040. When the access rate doubles, the hundreds of millions of dollars are saved annually, and transplant programs or treatments for kidney disease can be performed in turn. In addition, dialysis patients, especially those suffering from end stage kidney disease ("ESRD"), are able to lead a more productive, healthy and happy life.

For hemodialysis patients, arteriovenous fistula (AVF) is the preferred and most effective long-term approach. AVF is an artificial direct connection between arteries and veins. The large amount of blood flowing through these connections makes the veins larger and the walls of the arteries thicker. Thus, the AVF provides a large amount of blood flow sites that access the circulatory system to perform hemodialysis. For each dialysis two large diameter needles (typically 14 to 16 gauge) are inserted through the skin of the dialysis patient into the AVF on the "arterial" end and the "vein" end. When the tip of the bars is properly positioned inside the access portion, a large amount of blood enters the end of the tubing attached to each needle. Before starting the dialysis treatment, a stopper is removed from each tubing, so that blood fills the tubing, and then saline is injected through each tubing and needle by a syringe. The two needles are then connected to rubber tubing to the inlet (arterial) line and the outlet (vein) line of the dialysis machine, and dialysis is initiated.

Unfortunately, even with careful physical examination and / or Doppler ultrasound or angiography to identify appropriate veins, approximately 40-50% of patients report no vascular structure sufficient to produce primary AVF. It is becoming. In addition, many dialysis professionals who have already failed to use AVF can no longer be considered candidates for primary fistulas.

The next option for long term access is to locate arteriovenous grafts (“AVGs”). AVG is a plastic tube of length, generally made of porous polytetrafluoroethylene ("PTFE") surgically placed subcutaneously, in fluid communication between arteries and veins. Once the graft is positioned, the dialyzer can be fluidically connected to the patient's circulatory system by inserting the needle into the graft and connecting the needle to a dialyzer having tubing as described above in connection with the AVF. However, the term "long-term access" is an inadequate term for AVG, as it is frequently reported that the opening rate after one year is only 40%. to be. Despite graft surveillance and aggressive prevention to prevent thrombosis, primary and secondary open rates remain low; The incidence of additional costs is thought to be very high.

While many factors have a large impact on the limited durability of PTFE grafts, the most detrimental is the gradual development of neointimal hyperplasia (NIH) resulting in narrowing venous anastomotic and thus graft thrombosis. Thrombotic grafts may be surgically or percutaneously removed from clotting, or procedures using elaborate aatherectomy devices, angioplasties, or stents may still be used, but the NIH still recurs as expected. do. Although the graft can be calibrated so that the anastomosis is located proximally, it has also been found that the probability of failure is very high. There is a need to improve the AVG open rate in order to reduce costs and improve the quality of life of patients.

Neointimal hyperplasia can include, for example, damage to the endothelial (endothelium) that increases growth factors, turbulence at the anastomosis site, vibrational force at the anastomosis, shear force, uremia, and other hypothetical etiologies. It is believed to occur due to a number of factors, including. Many researchers have confirmed the development of NIH, which is constantly occurring at the site of venous anastomosis.

Physicians use stepped and tapered grafts, which typically have a gradually increasing diameter from the end of the artery to the end of the vein along a portion of the graft or over the entire length of the graft, having a maximum diameter of the graft. Terminate at the end of the vein with an opening at the point. One example of a tapered graft with a continuously increasing diameter is shown in FIG. 1, wherein the lumen diameter at the venous end 1 is greater than the diameter at the arterial end 2.

A common belief among practitioners is that by further increasing the size of the venous anastomosis, the development of NIH can be prevented or delayed. In an attempt to improve AVG durability, "hooded grafts" with larger venous anastomosis have been used. A representative example of a conventional hooded graft (Venaflo, Impra Company) is shown in FIG. 2 and the vein end 3 has a "hood" shape. However, no significant improvement has been reported using the hood graft. Indeed, it has been found that the Venaflo graft is in some cases shielded faster than a standard stepped graft. In addition, attempts to repair the graft by surgical or non-surgical thrombectomy have been found to be very difficult to achieve and have been found to result in relatively short secondary open rates.

Graft to supply blood from one artery to another by fluidly connecting the two arteries or to bypass a portion of the artery by fluidly connecting the ends of the graft to a single artery in two different locations Similar difficulties may arise when this is used. For example, the graft may be used if a portion of the artery is blocked or damaged, or if it is necessary or desirable to bypass the blood flow for a portion of the artery due to diminished blood flow or other factors. However, it will generally be appreciated that the placement of arterial bypass grafts results in a disruption of natural blood flow in the arteries, thereby exposing a serious risk of neointimal hyperplasia (NIH), distal anastomosis narrowing and graft thrombosis. .

In view of the above, there is a need for an alternative approach in the treatment and care of hemodialysis patients or in the treatment and care of other patients requiring placement of vascular grafts such as arterial bypass grafts. In particular, there is a need for new hemodialysis access grafts and new arterial bypass grafts and methods of surgically positioning the grafts. This need is addressed in the present invention.

This application is incorporated by reference in US Patent Provisional Application No. 60 / 224,392, entitled "ARTERIOVENOUS GRAFTS AND METHODS OF IMPLANTING THE SAME," filed August 10, 2000, which is hereby incorporated by reference in its entirety; US patent application Ser. No. 09 / 704,083, filed November 1, 2000, entitled "ARTERIOVENOUS GRAFTS AND METHODS OF IMPLANTING THE SAME"; United States Patent Provisional Application No. 60 / 297,088, entitled "DISTALLY NARROWED VASCULAR GRAFTS AND METHODS OF USING SAME FOR MAKING ARTERY-TO-VEIN AND ARTERY-TO-ARTERY CONNECTIONS", filed June 8, 2001; And US Patent Provisional Application No. 60 / 297,226, entitled "ARTERIOVENOUS GRAFTS AND RELATED DEVICES AND METHODS OF USING SAME," filed June 8, 2001.

The present invention provides vascular grafts and methods for transplanting the grafts. The present invention is in various aspects a vascular graft having a downward stepped distal end, a vascular graft having a cuff to assist in attaching the graft to a target vessel, a connector device for constructing connections between ends of the graft and It is about a method. In various embodiments of the invention, the vascular graft can be used to construct an arterial-to-venous connection (herein referred to as an arteriovenous graft) or to construct an arterial-to-arterial connection. .

1 shows a conventional standard tapered graft increasing in diameter from the proximal end 2 to the distal end 1.

2 illustrates a conventional hooded graft.

3 is a side view of an embodiment of a vascular graft in accordance with the present invention.

4 is a side view of another embodiment of a vascular graft in accordance with the present invention.

5 is a side view of another embodiment of a vascular graft in accordance with the present invention.

6 is a side view of another embodiment of a vascular graft in accordance with the present invention.

Figure 7 is a schematic partial cutaway side view of the graft after implantation of the graft of the present invention.

8 is a side view of an embodiment of a cuff according to the present invention.

9 is a side view of another embodiment of a vascular graft in accordance with the present invention.

10 is a side view of another embodiment of a vascular graft in accordance with the present invention.

Figure 11 is a schematic partial cutaway side view of the graft after implantation of the graft of the present invention.

12 is a perspective view of an embodiment of a connector device according to the present invention.

13 is a perspective view of the connector device of FIG. 12 showing the connection of the graft members.

14 is a perspective view of the connector device of FIG. 12 showing the connector device positioned to connect two graft members.

15 is a perspective view of another embodiment of a connector device according to the present invention;

16 is a perspective view of the connector device of FIG. 15 showing that the connector device is used for connection of the graft members.

17 is a perspective view of another embodiment of a connector device according to the present invention.

18 is a perspective view of another embodiment of a connector device according to the present invention.

19 is a perspective view of another embodiment of a connector device according to the present invention.

20 is a perspective view of another embodiment of a connector device according to the present invention.

FIG. 21 is a perspective view of the connector device of FIG. 12 showing the device positioned for connection of two graft members and the distal end of the connected graft located inside the vessel;

The present invention solves the problems associated with hemodialysis access grafts and other vascular grafts known in the art by providing novel grafts and methods for surgically positioning the grafts. Embodiments of the present invention illustrate various preferred aspects.

One form of the invention is a novel vascular graft with a downward stepped distal end. The distal end may comprise a region of generally uniform diameter adjacent to a stepped region generally adjacent to a region of larger uniform diameter. The stepped zone decreases in diameter in the direction of blood flow through the graft, ie in the direction toward the distal end. Optionally, the stepped zone of decreasing diameter may extend from an adjacent zone of larger diameter to the distal end. The stepped zones can vary in length and gradient and can provide a decreasing diameter, generally linear or nonlinear. Another form of the invention is a vascular graft that also has a stepped proximal end. In some embodiments, the graft of the present invention includes an externally detectable indicator, such as, for example, radiopaque marking, wherein the indicator facilitates subsequent identification and positioning of the graft. Facilitate surveillance and interventional therapy.

Another form is a novel vascular graft with a cuff positioned at a distance from the distal end to attach to the wall of the target vessel. The cuff defines a groove for receiving a purse-string suture in the vessel wall. The cuff may be a single unit attached to an outer surface of the graft or may include a plurality of units. In one embodiment, the cuff includes two rings around the circumference of the graft at predetermined locations spaced from each other to provide a groove between the suture and the vessel wall. In other embodiments, for example, at least a portion of the cuff, such as one or two of the rings, includes an externally detectable indicator, such as, for example, a radiopaque indicator, for subsequent identification and positioning of the anastomotic site. This facilitates and thus facilitates the surveillance and interventional treatment required for the graft.

Another aspect of the invention provides a method for making an incision in the wall of a target vessel, inserting the distal end of the graft of the invention into a vessel such that the distal end is located downstream of the incision site and securing the graft to the vessel wall. Vascular graft transplantation method comprising the steps. In an embodiment where a cuffed graft is used, the securing step includes forming a swatch closure that engages the groove of the cuff. In certain embodiments, the method also includes removing the middle portion of the graft to shorten the graft. For example, the middle portion of the graft can be removed by cutting the graft at two predetermined points spaced apart by a distance equal to the length to be removed, thereby providing two cut ends and connecting the cut ends to each other. Thereby providing a shortened graft.

In another aspect of the present invention, a connector device is provided that is advantageously used to assist in the connection of the ends of a plurality of conduits, such as, for example, blood vessels, grafts, and the like. For example, in an embodiment for connecting two conduits, the connector includes a first segment configured to insert at the end of one conduit and a second segment configured to insert at the end of the other conduit. In some embodiments, the device also includes an intermediate segment for maintaining the cut ends in a spaced apart relationship.

It is an object of the present invention to provide novel vascular grafts and methods of transplanting them that provide an alternative to unsatisfactory conventional grafts and methods.

Another object of the present invention is to provide a method and device for shortening a vascular graft by removing an intermediate portion from the graft.

Further forms, embodiments, objects, advantages, advantages, aspects, and features of the invention will become apparent from the accompanying drawings and the description herein.

While the specific forms of the invention are indicated in particular in the patent claims, the present invention and the manner in which it can be used and constructed by reference to the following description taken in conjunction with the accompanying drawings that form part of this application are more apparent. Can be understood.

For understanding of the principles of the present invention, specific embodiments are described with reference to suitable embodiments and specific terminology is used to describe suitable embodiments. It is to be understood that the above embodiments are not intended to limit the scope of the present invention, and that modifications other than the alternative embodiments in the present invention can be made by those skilled in the art.

In one aspect, the present invention provides a graft prosthesis (hereinafter referred to as “graft”) that includes a general tubular conduit that forms a lumen and has a tapered or downward distal end for flowing blood. The distal end is formed for insertion into the target blood vessel through the incision through the incision to direct blood flow away from the incision site and is provided for large laminar flow of blood from the distal end of the graft into the vein or artery and thereby turbulence at the anastomosis site. Decreases.

Referring to FIG. 3, which illustrates one embodiment of the present invention, the graft 10 includes a first end 20 (hereinafter referred to as the “distal end” of the graft) for insertion into a blood receiving conduit site, It has a second end 30 (hereinafter referred to as the "proximal end" of the graft) for attaching to the artery site selected for supplying blood to the graft. It will be understood by those skilled in the art that blood flows in a single direction through the vascular graft. As used herein, the terms "proximal end" and "distal end" are used herein consistently to identify the end of the graft relative to the direction of blood flow. As these terms are used herein, blood flows from the proximal end to the distal end. Blood, on the other hand, passes from the arterial site of the graft to the proximal end, flows through the graft to the distal end of the graft, and then into a transfusion vessel, such as a downstream location of a vein, a second artery or the same artery with fluid attachment to the proximal end. Flow to the site.

Graft 10 is generally made of a material having a uniform thickness, so graft 10 defines a lumen 11 having the same shape as the outer surface of the graft. In the graft 10, the distal end 20 defines an orifice 21 and the proximal end 30 defines an orifice 31. The portion of the graft lumen defined by the zone 22 of the graft 10 and the orifice 21 are less uniform than the diameter of the orifice 31 and the portion of the graft lumen defined by the zone 40 of the graft 10. Have a diameter. The portion of the graft lumen 11 defined by the zone 23, also referred to as the "staircase" zone or the "tapered" zone, is referred to herein as the longitudinal point adjacent zone 22 from the longitudinal point adjacent zone 40. Up to have a gradually increasing diameter, generally described as a continuous taper.

In one embodiment, the portion of the graft lumen 11 defined by the zone 40 has a diameter that is at least approximately 20% larger than the portion defined by the zone 22. In another embodiment, the portion of the graft lumen 11 defined by the zone 40 has a diameter that is at least approximately 30% larger than the portion defined by the zone 22. In another embodiment, the portion of lumen 11 defined by zone 40 has a diameter at least approximately 40% larger than the portion defined by zone 22. In another embodiment, the portion of the graft lumen 11 defined by the zone 40 has a diameter that is at least approximately 50% larger than the portion defined by the zone 22.

In one embodiment, the portion of lumen 11 defined by zone 22 has an inner diameter of less than approximately 6 mm. In another embodiment, the portion of lumen 11 defined by zone 22 has an inner diameter of less than approximately 5 mm. In another embodiment, the portion of lumen 11 defined by zone 22 has an inner diameter of about 3 mm to about 6 mm, and the portion of lumen 11 defined by zone 40 is about 4 mm to about It has an internal diameter of 8 mm. In another embodiment, the portion of lumen 11 defined by zone 22 has an inner diameter of about 3.5 mm to about 4.5 mm, and the portion of lumen 11 defined by zone 40 is about 5.5 mm to about It has an internal diameter of 7.0 mm.

In one embodiment, the zone 23 extends relative to the graft 10 to a length that is relatively short, for example less than approximately 2 cm. In this embodiment, the zone 23 is preferably located approximately 1 to approximately 10 cm from the distal end 20. In another embodiment, the zone 23 is located approximately 1 to approximately 8 cm from the distal end 20, and in another embodiment the zone 23 is approximately 1 to approximately 6 cm from the distal end 23. Is located in. In another embodiment, the zone 23 extends along the longer length of the graft, for example along a length longer than approximately 2 cm, thus providing a more viscous taper. In one embodiment, the zone 23 extends along the length of the graft from about 1 to about 10 cm.

In another embodiment, as shown in FIG. 4, the graft 10 does not include a region corresponding to the region 22 of FIG. 3, and the tapered region 123 has a larger diameter for the distal end 120. Tapered continuously from zone 140. In one embodiment, the zone 123 extends along the longitudinal axis of the graft 110 from a longitudinal point that is at least approximately 2 cm from the distal end 120. In another embodiment, zone 123 extends from a longitudinal point that is at least approximately 4 cm from distal end 120. In another embodiment, zone 123 extends from a longitudinal point that is approximately 2 cm to approximately 15 cm from distal end 120. In another embodiment, zone 123 extends from a longitudinal point that is about 4 cm to about 15 cm from distal end 120. In another embodiment, zone 123 extends from a longitudinal point that is approximately 2 cm to approximately 10 cm from distal end 120. In another embodiment, zone 123 extends from a longitudinal point that is about 4 cm to about 10 cm from distal end 120.

Referring to FIG. 5, in another embodiment of the present invention, in addition to having a downward stepped distal end portion, the graft 210 also has a downward stepped proximal end portion. Graft 210 has a first end 220 for insertion of a blood vessel site for transfusion and a second end 230 for attachment to an artery site selected for supplying blood to the graft. In the graft 210, the distal end 220 defines an orifice 221 and the proximal end 230 defines an orifice 231. The portion of the graft lumen defined by the region 222 of the graft 210 and the orifice 221 have a generally uniform diameter that is less than the diameter of the portion of the graft lumen defined by the region 240 of the graft 210. In addition, the portion of the graft lumen and orifice 231 defined by the region 232 of the graft 210 has a generally uniform diameter that is less than the diameter of the portion of the graft lumen defined by the region 240 of the graft 210. . The portion of the graft lumen 211 defined by the zone 223, also referred to as the "staircase" zone or the "tapered" zone, generally extends from the longitudinal point adjacent zone 240 to the longitudinal point adjacent zone 222. It has a gradually increasing diameter and is also generally described herein as a continuous taper. Similarly, the portion of graft lumen 211 defined by zone 233, also referred to herein as a “staircase” zone or “tapered” zone, is generally from a longitudinal point adjacent to zone 232. It has a uniformly increasing diameter to the longitudinal point adjacent to zone 240.

In one embodiment, the portion of graft lumen 211 defined by zone 240 has a diameter that is at least approximately 20% larger than the portion defined by zone 222 or zone 232. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a diameter that is at least approximately 30% larger than the portion defined by the zone 222 or the zone 232. In another embodiment, the portion of the graft lumen 211 defined by the region 240 has a diameter that is at least approximately 40% larger than the portion defined by the region 222 or the region 232. In another embodiment, the portion of the graft lumen 211 defined by the region 240 has a diameter that is at least approximately 50% larger than the portion defined by the region 222 or the region 232. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a length that is at least approximately 50% of the graft length. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a length that is at least approximately 60% of the graft length. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a length that is at least approximately 70% of the graft length. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a length that is at least approximately 80% of the graft length. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a length that is at least approximately 90% of the graft length. In another embodiment, the portion of the graft lumen 211 defined by the zone 240 has a length that is at least approximately 95% of the graft length.

In one embodiment, the portion of lumen 211 defined by zone 222 has an inner diameter of less than approximately 6 mm. In another embodiment, the portion of lumen 211 defined by zone 222 has an inner diameter of less than approximately 5 mm. In another embodiment, the portion of lumen 211 defined by zone 232 has an inner diameter of less than approximately 6 mm. In another embodiment, the portion of lumen 211 defined by zone 232 has an inner diameter of less than approximately 5 mm. In another embodiment, the portion or portions of lumen 211 defined by one or both of zones 222 and 232 have an inner diameter of about 3.5 to about 6 mm, and is defined by zone 240. The portion of lumen 211 that is defined has an inner diameter of about 4 to about 8 mm. In another embodiment, the portion or portions of lumen 211 defined by one or both of the zones 222 and 232 have an inner diameter of approximately 3.5 to approximately 4.5 mm, The portion of lumen 211 defined by has an inner diameter of about 5.5 to about 7.5 mm. In another embodiment, the portion or portions of lumen 211 defined by one or both of the zones 222 and 232 have an inner diameter of approximately 3.5 to approximately 4.5 mm, The portion of lumen 211 defined by has an inner diameter of about 5.5 to about 6.5 mm. In another embodiment, the portion or portions of lumen 211 defined by one or both of zones 222 and 232 have an inner diameter of approximately 4 mm and are defined by zone 240. The portion of 211 has an inner diameter of approximately 6 mm.

The zones 223, 233 may extend, for example, with a length of less than approximately 2 cm, for a relatively short length of the graft 210. In this embodiment, the zone 223 is preferably located approximately 1 to approximately 10 cm from the distal end 220, and the zone 233 is preferably approximately 1 to approximately 10 cm from the proximal end 230. Is located at the point. In another embodiment, zone 223 is located approximately 1 to approximately 8 cm from distal end 220, and zone 233 is approximately 1 to approximately 8 cm from proximal end 230. In another embodiment, zone 223 is located approximately 1 to approximately 6 cm from distal end 220, and zone 233 is approximately 1 to approximately 6 cm from proximal end 230. It will be appreciated that the zones 223, 233 can have the same length or different lengths. Optionally, the zones 223 and 233 may each extend along a graft of longer length, for example approximately 2 cm or more, thereby providing a progressive taper. In one embodiment, the zones 223 and 233 extend along the length of the graft, which is approximately 2 to approximately 10 cm each.

In another embodiment shown in FIG. 6, the graft 310 does not include a region corresponding to the regions 222, 232 of FIG. 5. Rather, the tapered region 323 is generally tapered continuously from the larger diameter region 340 to the distal end 320, and the tapered region 333 is generally larger than the proximal end 330. It is characterized by a continuous increase in diameter up to zone 340 in diameter. One or both of the zones 323, 333 typically extend along the longitudinal axis of the graft 310 to a longitudinal point at least approximately 2 cm away from each end 320, 330. In other embodiments, one or both of these zones 323, 333 extends to a longitudinal point at least approximately 4 cm away from each end 320, 330. In other embodiments, one or both of these zones 323, 333 extends to longitudinal points approximately 2 cm to 15 cm away from each end 320, 330. In other embodiments, one or both of these zones 323, 333 extends to longitudinal points approximately 4 cm to 15 cm away from each end 320, 330. In other embodiments, one or both of these zones 323, 333 extends to longitudinal points approximately 2 cm to 10 cm from each end 320, 330. In other embodiments, one or both of these zones 323, 333 extends to longitudinal points approximately 4 cm to 10 cm away from each end 320, 330.

The graft described herein is usually made of polytetrafluoroethylene (PTFE), but the material of the graft in the present invention is not limited thereto. Grafts can be made from a wide range of biocompatible materials that are known so far or will be improved in the future as long as physical properties such as flexibility are acceptable.

According to the present invention, there is also provided a method of implanting a graft surgically. In order to install the graft according to the invention, an incision is made to the blood vessel at a location selected for receiving blood from the graft and the distal end of the graft is introduced into the vessel from the incision and installed at a predetermined location downstream of the incision. In the incision, the graft is secured to the wall of the vessel. The shape of the graft relative to the target vessel after installation is shown in FIG. 7, wherein the distal end 360 of the graft 365 is the target at the incision 380 downstream position for the natural flow of blood in the vessel 370. Disposed in the blood vessel 370.

In one embodiment, attaching the distal end of the graft of the present invention to the target vessel comprises (a) dissecting the wall of the target vessel at a predetermined point, and (b) distal end of the graft with the first end downstream of the incision. Inserting into the vessel through the incision through the incision, (c) securing the graft to the vessel in the incision, and (d) anastomizing the proximal end to the preselected artery site. In one embodiment, the distal end of the graft can be advantageously secured to the target vessel using a bag closure. In one embodiment of the invention, the ssam suture may be inserted prior to incision into the wall of the target vessel. In another embodiment, the insert includes inserting the distal end of the graft through the incision into the blood vessel and passing it through at least approximately 1 cm downstream of the incision. In another embodiment, the insert comprises inserting the distal end of the graft through the incision into the blood vessel and passing it to a point approximately 1-4 cm downstream of the incision. In another embodiment, the insert comprises inserting the distal end of the graft through the incision into the blood vessel and passing it through at least approximately 1 to 3 cm downstream of the incision. Inserting the distal end of the graft into the blood vessel flows blood away from the incision and thus reduces the violent flow of blood at the anastomotic site.

One advantage of the present invention is that the distal end of the graft can be placed in transfusion vessels of various sizes, including vessels that were previously considered inadequate due to size limitations. In one embodiment of the invention, the transfusion vessels at the target attachment location selected for anastomosis have a diameter of less than approximately 1.5 cm. In another embodiment, the selected transfusion blood vessel at the target attachment location has a diameter of approximately 0.4-1.5 cm. In another embodiment, the selected transfusion blood vessel at the target attachment location has a diameter of less than about 1.4 cm. In another embodiment, the selected transfusion vessel at the target attachment location has a diameter of less than approximately 1.3 cm. In another embodiment, the selected transfusion blood vessel at the target attachment location has a diameter of less than approximately 2 cm. It is also contemplated that the present invention can be used to install the graft of the present invention in large vessels, such as those in the legs of a patient. Thus, in another embodiment, the selected transfusion vessel at the target attachment location has a diameter of up to approximately 3.0 cm.

In another aspect, the present invention provides a graft with a cuff positioned at a distance from the distal end of the graft, wherein the cuff receives the bagged suture at the incision during surgical installation of the graft to repair the damaged endothelial at the incision. It acts to isolate from the intravascular portion of the anastomosis. In this regard, in one aspect of the invention, a graft with a cuff attached to its outer surface is provided, the cuff defining a groove shaped to receive the swatch closure for anastomosis. It is to be understood that the present invention contemplates the use of such cuffs with grafts having tapered or downward stepped distal ends as described herein, as well as standard grafts such as grafts that do not taper at the distal end.

In one embodiment, the cuff is shaped such that the groove is disposed on a plane perpendicular to the longitudinal axis of the graft. This arrangement makes it easy to see that when the graft is sutured to the vessel wall, the graft will pass through the vessel at a 90 ° angle to the vein. In another embodiment, the cuff is shaped such that the grooves are disposed on a plane at an angle to the longitudinal axis of the graft, as shown in FIGS. 9 and 10. In other embodiments, the grooves are disposed on a plane having an angle of approximately 45 ° with respect to the longitudinal axis of the graft, but the present invention contemplates various angles.

In one embodiment, the cuff has a single structure forming a groove. For example, FIG. 8 shows the cuff 650 to be attached to the outer surface of the graft. Cuff 650 defines a lumen 651 sized to engage the outer surface of the graft at the desired location. The cuff 650 also includes a first ridge 652 and a second ridge 653, which ridges extend around the cuff and form grooves 655 therebetween. The cuff 650 may be attached to the graft at a location using a biocompatible adhesive or may be integrally formed with the graft.

In another embodiment, the cuff may have two ring structures extending around the graft and forming a groove therebetween. Referring now to FIGS. 9 and 10, the grafts 410 and 510 have cuffs 450 and 550 attached or integrally molded to their outer surfaces, respectively. Each of the cuffs 450, 550 has two ring structures 452, 453, 552, 553, each shaped to receive a bag closure for venous or arterial anastomosis.

In one embodiment, the groove is disposed at least approximately 1 cm from the distal end. In another embodiment, the groove is disposed approximately 1-5 cm from the distal end. In another embodiment, the groove is disposed approximately 1 to 3 cm from the distal end. It will be readily understood that the distance from the distal end affects the length of the graft remaining in the target vessel after completion of the graft transplant. In one embodiment, for example, the cuff is positioned such that the groove defined by the cuff is located approximately 1 to 3 cm from the distal end of the graft. In another embodiment the cuff is positioned such that the groove defined by the cuff is located approximately 1.5-2.5 cm from the distal end of the graft. In another embodiment the cuff has two ring structures, as shown in FIGS. 9 and 10, with one ring disposed approximately 1.75 cm from the distal end of the graft and the other ring approximately 2.25 cm from the distal end. It is disposed in, and forms a groove therebetween.

In another embodiment of the present invention, at least a portion of the graft is coated and / or impregnated with an antithrombogenic material. In one embodiment, the surface of the graft in contact with blood is coated and / or impregnated with an antithrombogenic material. The presence of an antithrombotic agent on the surface of the graft has the advantage of inhibiting coagulation or adhesion of blood on the surface. In accordance with an embodiment of the invention the surface on which the antithrombogenic material can be coated and / or impregnated is the surface of the graft lumen and the distal end to be inserted into the target transfusion vessel (ie, between the cuff and the distal end in a graft having a cuff). The outer surface of the portion of the cuff and the cuff portion (ie, the cuff portion closest to the distal end of the graft) to be placed in the lumen of the target vessel, if present. Suitable antithrombogenic materials that can be used to coat and / or impregnate the graft surface include, for example, carbon, heparin, silicone.

In another embodiment, at least a portion of the cuff has an externally detectable display such as, for example, a radiopaque display. The presence of such indicators allows the position of the cuff to be externally determined using radiation or other means, and thus the position and / or location of the graft's diameter change based on the relative position of the cuff on the graft. It allows you to determine where blood vessels enter. This knowledge facilitates post-installation surveillance or interventional treatment that the graft may require. In some particular embodiments, one or both of the ridges or rings of the cuff include externally detectable indicators. In another embodiment, one or two ends of the graft include an externally detectable indicator to facilitate subsequent methods for externally identifying the location of one or more ends of the graft. In one embodiment, the vein end is indicated by an externally detectable indicator.

As used herein, the term "externally detectable" is intended to refer to a state of a material, whereby the material is a fluoroscopy instrument, x-ray instrument, CT instrument, MRI instrument, ultrasound instrument, and other forms of remote imaging. It can be imaged with imaging equipment such as equipment. Various medical imaging equipment is commercially available. As used herein, the term "externally detectable" includes not only radiopaque materials, but also materials that can be detected by medical imaging equipment due to different densities or other properties than the surrounding material. For example, fluoroscopy can be used in the case of radiopaque materials. The radiopaque material selected for use according to the invention may be a barium mixture, for example barium sulfate, for example a metal component such as tantalum or other radiopaque material. Those skilled in the art will be able to select a radiopaque material suitable for use with the present invention. Optionally, MRI or ultrasound may be used to detect materials that differ in density from the human body and other surrounding materials.

An externally detectable indicator may be used, for example, by injecting an externally detectable inert material into the paint, or by applying another coating to a portion or cuff or portion of the graft, such as the graft end; By making a portion or cuff or portion thereof from an externally detectable material; Alternatively, externally detectable material may be provided by injecting a portion of the graft or polymer used to form the cuff or portion thereof.

The invention also provides, in certain embodiments, a method for noninvasive monitoring of a patient having a subcutaneous graft of the invention. The method according to one embodiment, in the formation of the graft of the present invention, the externally detectable material is added, in the case of radiopaque material, x-ray or fluoroscopic imaging, or in the case of a material having a density difference Examining the location and / or patency of the graft by examining the patient using non-invasive techniques such as MRI or ultrasound scanning.

Also provided is a method of implanting a graft of the invention having a cuff as described herein in accordance with the present invention. For placement of the graft having a cuff according to the present invention, an incision is made in the target vessel and the distal end of the graft is introduced into the vessel, whereby the cuff is positioned so that the groove receives the vessel wall in the incision position. And the vessel wall is fixed to the graft. A representative structure of the cuff graft for the target vessel after placement is shown in FIG. 11, where the distal end 460 of the graft 465 is at a position downstream from the incision position relative to the natural blood flow of the vessel 470. It is arranged in the target blood vessel 470. Cuff 480 is positioned so that the groove thus formed receives the vessel wall in the incision position.

In one embodiment, the anastomosis is (1) making an incision in the wall of the desired target vessel; (2) inserting the distal end of the cuff-shaped graft into the vessel through this incision so that the groove is positioned to receive the vessel wall and suture; (3) fix the wall to the cuff; (4) Achievement is achieved by fixing the second end to a predetermined target artery position. In one embodiment, the distal end of the graft can be secured appropriately to the blood receiving vessel location using a bag closure. In one manner of practicing the present invention, the ssam suture is inserted into the wall of the target vessel prior to making an incision, and the fixation may include securing the vascular wall to the cuff using the ssam suture. Furthermore, in addition to bypassing blood flow from the incision site, reducing the force of the graft on the anastomotic location, and forming a thinner blood flow, the use of the present invention can reduce the amount of damage to the vascular endothelium produced by the incision and suture. It can be significantly reduced. In addition, constructing an anastomosis using cuff and wedge closure in accordance with the present invention allows for isolation of the incision itself (ie, the cut edge of the vessel wall) from the interior of the vessel. Thus, the blood in the graft and blood vessels does not contact the incision site.

It is also to be understood that the present invention also encompasses the use of cuffs in conjunction with standard grafts, ie, grafts whose distal ends are not tapered. Additionally, although embodiments including cuffs are shown and described herein, the invention is not limited to grafts with cuffs, and certain embodiments of the invention as described above also provide structures that do not include cuffs. do. In the absence of cuffs, the graft may be anastomated in the blood receptive vascular location using other techniques known in the art, and the graft may optionally be an alternative for attachment to the vascular location as known in the art. It may include a suture.

Looking at other useful features of the present invention, one of ordinary skill in the art will readily understand that graft placement typically involves a change in the length of the implant to be placed. As an example, arteriovenous grafts are typically made to have an excess length that can be removed if necessary. One reason for having this excess length is to provide a graft that can be used for patients of all sizes. In addition, this provides the surgeon placing the graft with the freedom in selecting an appropriate subcutaneous route through which the graft will be placed from the target arterial position to the target venous position. Thus, during placement of the arteriovenous graft, the portion of the graft determined to be left is generally removed by cutting the appropriate length from one end of the graft. In this regard, during placement of the arteriovenous graft, the graft may proceed tunneling subcutaneously from a point near the target venous anastomosis location to the point near the arterial anastomosis location (or vice versa). The excess length is then cut from one or both ends as needed to provide an end of the graft that is properly positioned for attachment to each vessel. Similar techniques are commonly used in procedures for arterial-aortic-arterial placement.

It is evident that the procedure described above is inadequate for implant placement procedures having specially required structures, such as tapered or stepped distal ends and tapered or stepped proximal ends, in accordance with certain aspects of the present invention. . In the placement of this type of graft, it is usually not acceptable to reduce the length of the graft by simply cutting a certain length from one end of the graft. Thus, to reduce the length of the graft, it is necessary to remove a predetermined length from the center of the graft, and then connect the two cut ends end to end to provide a continuous graft conduit. In addition to the above, it is necessary to achieve end-to-end connection of the two members of the graft even when existing arteriovenous grafts such as bypass grafts have to be retrofitted. This type of modification typically involves carrying out end-to-end connection of the graft member. However, for either new or modified arteriovenous graft, sealing the two members of the PTFE graft together is time consuming, cumbersome, and can lead to ingrowth of the wound and / or tissue at the junction. Thus, suturing the graft member together in an end-to-end manner can lead to stenosis that can lead to thrombosis or destruction of the graft if it is significantly larger. Additionally, suturing the two ends of the PTFE graft together may result in significant bleeding at the anastomotic position, additionally increasing surgical time and cost.

In another aspect of the invention, a connector device is provided that is suitably used to assist in the connection of the end of the graft member. The connector device of the present invention is suitably used, if necessary, to reduce the length of the arteriovenous graft by removing the central part therefrom. In certain embodiments of the present invention, after the central portion is removed, the two cut ends of the graft are connected using the connector device of the present invention. Of course, the present invention is not limited to connecting two cut ends of the arteriovenous catheter. The connector device of the present invention can be used to connect a wide variety of conduits in an end-to-end manner.

In one embodiment shown in FIG. 12, the connector 710 is generally tubular and in fluid with lumens 761, 762 or other conduits 771, 772 of the graft connected as shown in FIGS. 13 and 14. The lumen 750 is configured to be in communication. The connector 710 is configured to be inserted into the first end segment 720 configured to be inserted into the end 773 of the first graft or other conduit 771 and into the end 774 of the second graft or other conduit 772. A second end segment 740 and a larger outer diameter central segment 730 configured to hold the graft member ends 773, 774 in a spaced apart relationship.

In another embodiment, the connector 710 also includes means for attaching the graft members 771, 772 to the connector 710. In one embodiment, for example, an adhesive composition is provided on the outer surfaces of the first end segment 720 and the second end segment 740 such that the connector is placed in place after the connector is placed in contact with the graft members 771, 772. 710). In another embodiment shown in FIG. 15, each of the first end segment 720 and the second end segment 740 may be a fastener such as, for example, a clamp, a clip, a tie filament, or the like. Grooves 781 and 782 are formed for receiving. 16 illustrates a representative example of a connector 710 according to the present embodiment connected to graft members 771 and 772 by tie filaments 771 and 792 positioned to engage grooves 781 and 782. In another embodiment shown in FIG. 17, one or both of the grooves are formed between ridges or rings 783, 784, 785, 786 formed around the segments 720 and / or 740. Of course, the ridge or ring may be configured to form a groove therebetween, but it is understood that it is appropriate that it is not large enough to make insertion of this segment into the graft end difficult. In another embodiment, shown in FIG. 18, one or each of the first end segment 720 and the second end segment 740 is configured to engage fasteners such as, for example, clamps, clips, tie filaments, and the like. Or rings 788 and 789. The connector of this embodiment inserts the segments 720 and 740 into the graft ends, so that the graft ends extend over the ridges 788 and 789, and then place the selected fixture in a position proximate the ridge to place the graft from the end segment of the connector. It can be secured to the graft end by preventing the end from slipping. Of course, it is of course possible to understand that the connector of the present invention may be attached to the graft member in other ways that one skilled in the art can perform.

In another embodiment of the present invention shown in FIG. 19, there is no middle segment of larger outer diameter, and the connector 710 has a first segment 720 configured to be inserted into an end of the first conduit, And a second segment configured to be inserted into the end. The connector 710 forms a groove 781 for receiving a fastener such as, for example, a clamp, clip, tie filament, or the like.

The connector of the present invention is suitably made of a relatively rigid biomaterial. While the robustness of the connector of the present invention may vary, the connector may be a graft member and the force of a filament clip or other device used to secure the graft member to the connector. Suitable enough to withstand the handling and insertion into the interior. Of course, it is also important that the connector is strong enough to prevent twisting or collapse at the connecting position. It is also important to use materials that prevent the connector from biologically deteriorating in the environment in which it is placed. As an example, the connectors used for connection of the absence of arteriovenous grafts or arterial bypass grafts should be made of a suitable material that does not degrade in the presence of blood under physiological conditions. The selection of suitable materials can be made well in the field of those skilled in the art, and various suitable materials are commercially available.

The connector of the invention is suitably sized to fit tightly at the end of the conduit to be connected. The tight fit prevents the formation of spaces or gaps between the connector and each graft end and facilitates securing the connector to the graft end. Thus, it will be appreciated that connectors of different dimensions are suitable for connection of grafts of different dimensions. In a particular embodiment of the present invention as shown in FIG. 20, the connector 710 includes tapered end portions 721 and 741 to facilitate insertion of the connector end into each graft end. Of course, the ends are suitable not to cause significant turbulence in the blood flow through the graft and the connector after placement of the connector, or to have a level of taper to occlude the blood flow. It is possible to select taper dimensions that achieve good results of the present invention within the scope of those skilled in the art. In addition, the insertion of the connector of the present invention into the graft end can be further facilitated, if necessary, by bringing the surface of the connector wet with saline to lubricate the connector prior to insertion. Of course, alternative biocompatible fluids can be used to wet and / or lubricate the connector, and those skilled in the art can select a fluid suitable to achieve this result.

The connector of the present invention is expected to be widely used for connecting graft members having a substantially uniform inner diameter. In one embodiment of the invention, the outer diameter of the first end segment and the outer diameter of the second end segment are approximately the same. Many arteriovenous grafts have internal diameters of, for example, about 5 to about 8 mm. Thus, in one preferred embodiment, the outer diameter of the first end segment and the outer diameter of the second end segment are approximately 5 to approximately 8 mm. Of course, it will be appreciated that the connector of the present invention may be used to connect graft members or other conduits with different inner diameters. The connector used to connect this graft has, of course, a first end segment with an outer diameter different from the second end segment. In a preferred embodiment, the diameter of the first end segment and the diameter of the second end segment are each within approximately 0.5 mm of the inner diameter of the target graft member.

The connector device of the present invention does not need to form a straight lumen as shown in the figure. Rather, in certain embodiments, the connector of the present invention is curved.

Thus, in one embodiment of the present invention, a catheter graft is provided, which comprises: (1) a distal end that is adapted for placement in a blood transfusion vessel and forms a first orifice having a first diameter; (2) a proximal end adapted for attachment to an artery location; (3) a first tubular portion forming a portion of a lumen having a substantially constant second diameter greater than the first diameter; (4) It is clear from this specification that a conduit graft is provided that includes a first tapered portion between the first tubular portion and the distal end, having a diameter that decreases substantially gradually along the first tapered portion. In another embodiment, the graft includes a second tubular portion between the distal end and the first tapered end, the second tubular portion forming a portion of a lumen having a substantially constant diameter corresponding to the first diameter.

In another embodiment, the proximal end of the graft defines a second orifice having a third diameter less than the second diameter, the graft having a second taper zone between the proximal end and the first tubular zone, and the second taper zone Generally have a uniformly increasing diameter. In another embodiment, the graft has a third tubular section between the proximal end and the second tapered section, the third tubular section defining a portion of the lumen having a generally constant diameter corresponding to the third diameter.

In another embodiment, the cuff is attached to the outer surface of the graft at least about 1 cm from the distal end, the cuff defining a groove configured to receive the swatch closure for anastomosis. In another embodiment, the groove is generally located on a plane that is at an angle of approximately 45 ° with respect to the longitudinal axis of the graft. In one embodiment the cuff has a tubular member defining a lumen dimensioned to engage an outer surface of the graft and a first and second ridge extending around the member and defining a groove therebetween. In another embodiment, the cuff has a first ring member attached to the graft and a second ring member attached to the graft, the first and second ring members defining grooves therebetween.

In another embodiment, the other portion of the cuff or graft has an externally detectable indicator. In certain embodiments, the externally detectable indicator is a radiopaque indicator, and in other embodiments, the externally detectable indicator comprises a material having a different density from that of the patient's body. In certain embodiments, the cuff or other portion of the graft is coated with other coating composition including paint or externally detectable material.

Another aspect of the present invention includes the steps of (1) forming an incision in the wall of a predetermined target blood vessel; (2) providing a vascular graft according to the present invention; (3) inserting the distal end of the graft through the incision into the blood vessel such that the distal end passes through a downstream point of the incision; (4) securing the graft to the vessel wall; And (5) anastomizing the proximal end of the graft at the desired target artery site.

In another form of the invention, the graft is secured to the blood vessel using a wrapper suture. In another form of the present invention, the wrapper suture is inserted into the wall of the target blood vessel before forming the incision. In another aspect of the invention, the inserting step includes inserting the distal end into the blood vessel through the incision such that the distal end passes at least about 1 cm on the downstream side of the incision. In another embodiment of the present invention, the graft has a cuff attached to the outer surface of the graft at least approximately 1 cm from the distal end, the cuff defining a groove formed to receive the bag closure for anastomosis. In this embodiment, the inserting step includes inserting the distal end of the graft through the incision into the vessel in such a way that the groove is arranged to receive the vessel, wherein the securing step includes securing the vessel wall to the cuff. In another manner of practicing the present invention, the bagging suture is inserted into the wall of the target blood vessel prior to making the incision, and the fixing step includes drawing the bagging suture into the groove.

In another aspect of the invention, the method comprises the steps of: (1) anastomizing a first end of a vascular graft into a first blood vessel; (2) anastomosis of the second end of the graft into the second blood vessel; (3) cutting the graft at two locations between the first and second ends to remove the intermediate portion of the graft, thereby providing a first graft member comprising the first end and a second graft member comprising the second end; step; (4) providing a generally tubular connector device having a first end segment configured to be inserted into the lumen of the first graft member and a second end segment configured to be inserted into the lumen of the second graft member, thereby defining the lumen step; And (5) connecting the first and second graft members to the first and second portions of the connector device. In certain embodiments, the connector device also has an intermediate segment configured to hold the graft member end in a spaced apart relationship. In another embodiment, each of the first and second end segments defines a groove or one or more rings for receiving clips, clamps, tie filaments, and the like for attachment of the segments to the first and second graft members. In another embodiment, the first and second end segments are coated with an adhesive composition to attach the segments to the first and second graft members. In another embodiment, the connection comprises: (1) inserting a first portion into the lumen of the first graft member; (2) securing the second portion to the second graft member; (3) inserting a second portion into the lumen of the second graft member; (4) achieved by securing the second portion to the second graft member.

In another aspect of the invention, there is provided a generally tubular connector device defining a through lumen, the device comprising: (1) a first end segment configured to be inserted into a lumen of a first graft member; (2) a second end segment configured to be inserted into the lumen of the second graft member; And (3) an intermediate segment configured to hold the graft member end in a spaced apart relationship, wherein the first and second end segments are coated with an adhesive composition to attach the segment to the first and second graft members.

In another aspect, the present invention provides a generally tubular connector device defining a lumen therethrough, the device comprising: (1) a first end segment configured to be inserted into a lumen of a first graft member; And (2) a second end segment configured to be inserted into the lumen of the second graft member, each of the first and second end segments each having a clip, clamp for attachment of the segment to the first and second graft members. Define a groove or one or more rings for receiving tie filaments and the like.

In another aspect, the present invention provides a generally tubular connector device defining a lumen therethrough, the device comprising: (1) a first end segment configured to be inserted into a lumen of a first graft member; (2) a second end segment configured to be inserted into the lumen of the second graft member; And (3) an intermediate segment configured to hold the graft member end in a spaced apart relationship, wherein each of the first and second end segments each includes a clip, clamp, tie for attachment of the segment to the first and second graft member. Define a groove or one or more rings for receiving a filament or the like. In certain embodiments, the groove or ring is configured to receive a bag closure.

In certain embodiments, the lumen of the connector device is substantially straight. In another embodiment, the connector is not straight.

As noted above, one advantage of the present invention is the use of a graft having a tapered or downward stepped distal end to reduce the size of the incision, which reduces endothelial damage and reduces NIH-induced falls. It is expected to make. Moreover, in embodiments having a cuff on the graft, the wrap suture may exclude the damaged endothelial from the vascular portion of the anastomosis. The cuff can also prevent slipping or dislodgement of the swatch closure, which can cause a clearly dangerous result. Reducing the diameter of the graft at the outlet also serves to suppress turbulence and make the flow more laminar.

While it is evident that the taper formation of the distal end can affect blood flow rate and pressure in the graft of the present invention, the graft of the present invention is considered to exhibit good long-term flow rate characteristics and also exhibit other advantages apparent from the description of the present invention. . Indeed, researchers conducting a graft examination study reported that a large proportion of functional AVGs had anastomosis or other constrictions larger than 50% of their original diameter. Other researchers reported that "the critical stenosis for thrombosis is approximately 70% of the diameter." Hakim and Himmelfarb (1998). In the graft of the present invention having a 4 mm distal end stepped downward from the 6 mm zone, the diameter is actually reduced at the distal end, but only by 33%. In addition, in embodiments tapered at each end (ie, distal end and proximal end), the volume flow rate through the graft may not be so changed by having a downward stepped distal end.

It is anticipated that the resistance to flow rate caused by having a tapered distal end can cause a decrease in flow rate in the portion of the graft with the larger diameter. Flow rates greater than 800 ml / min have been reported to be critical for the thrombosis of the present invention. Hakim and Himmelfab (1998). For the reasons mentioned above, the graft of the present invention may remain in the patient for an acceptable time with appropriate blood pressure and arterial inflow. Although thrombosis of the large diameter portion of the graft of the invention resulting from reduced flow rate may be a problem for the use of the graft of the invention, the increased tendency to thrombosis if present is an anticoagulant and / or antiplatelet It can be treated by using medicine.

In addition, Lumsden reported that the length of the 4 mm diameter zone on the step graft in the arterial anastomosis may adversely affect the opening rate if it is more than 2 cm. This difference is not explained in statistically significant cases, but is consistent with Poisel's law and in agreement with the results of the studies of Hakim and Himmelfab with flow rates. If we apply the Hagen-Poisel law,

If other variables are constant, if the radius R of the tube is reduced, the volume flow rate Q is decreased but not linearly reduced. As the length L (of the narrow region) increases, the flow rate Q also decreases. Rumsden's findings can be similarly applied to the distal end. Thus, one embodiment of the present invention has a downward stepped distal end having dimensions (ie, the radius and length of the downward stepped portion) that do not significantly increase the risk of thrombosis of the graft. In one preferred embodiment, the downward stepped distal end has a length of about 3 cm or less. In another embodiment, the downward stepped distal end has a length of about 2 cm or less. In another embodiment, the downward stepped distal end has a length of less than approximately 1 cm.

As mentioned above, widespread confidence and current trend is to implant grafts with relatively large venous anastomosis. This conviction and tendency is the fact that distal end graft occlusion may be delayed in grafts with large venous anastomosis because a greater degree of stenosis may be required to narrow the venous anastomosis beyond the critical size needed for opening rate. Are considered to result from. One skilled in the art does not find motivation in the prior art using AVG with smaller distal ends, and indeed one skilled in the art concludes that smaller anastomosis can cause accelerated points of critical stenosis and occlusion. Can be lowered. It is contemplated that smaller anastomosis in the conventional manner (from end to side) may cause a more rapid “critical stenosis” along with the formation of NIH and thrombosis, but the present invention is directed to an AVG having a downward stepped or tapered distal end. Provided are novel devices and methods that allow for deployment.

All references, including publications, patents, and patent applications cited or listed herein, are hereby incorporated by reference as if each individual reference were specifically and individually described herein in their entirety by reference. Coalesced by In addition, any theory, operation mechanism consistent with the purpose, or findings referred to herein is merely to aid the understanding of the present invention, and in any way limits the present invention to an operation mechanism consistent with the theory, purpose, or discovery. It is not intended to be. Although the invention has been shown and described in detail in the drawings and foregoing description, it should be considered that the invention is only for the purpose of illustration and not of limitation, the above preferred embodiments are only for illustration and description. It will be understood that all modifications, equivalents, and modifications which do not depart from the spirit of the invention as defined by the claims should be protected.

Claims (64)

In a vascular graft that defines a lumen for blood passage, A distal end adapted to be positioned within the blood vessel for transfusion through the wall of the vessel and defining a first orifice having a first diameter; A proximal end adapted to attach to the arterial site, A first tubular zone positioned between the distal end and the proximal end and defining a portion of the lumen having a uniform second diameter greater than the first diameter; And a first taper zone positioned between the first tubular zone and the distal end, the taper zone having a gradually decreasing diameter. The vascular graft of claim 1 wherein the second diameter is at least approximately 20% greater than the first diameter. The vascular graft of claim 1 wherein the second diameter is at least approximately 30% greater than the first diameter. The vascular graft of claim 1 wherein the first diameter is less than approximately 6 mm. The vascular graft of claim 1 wherein the first diameter is less than approximately 5 mm. The vascular graft of claim 1 wherein the first diameter is about 3.5 to about 4.5 mm and the second diameter is about 5.5 to about 7.0 mm. The apparatus of claim 1, further comprising a second tubular zone between the distal end and the first taper zone, the second tubular zone defining a portion of the lumen having a uniform diameter corresponding to the first diameter. Vascular grafts. 8. The vascular graft of claim 7 wherein the longitudinal length of the first tapered region is less than approximately 2 cm. 8. The vascular graft of claim 7 wherein the first tapered zone is located approximately 1 to approximately 10 cm from the distal end. The vascular graft of claim 1 wherein the longitudinal length of the first tapered region is approximately 2 to approximately 10 cm. The vascular graft of claim 1 wherein the first tapered region extends from the distal end to a longitudinal point that is at least approximately 4 cm from the distal end. The vascular graft of claim 1 wherein the first tapered zone extends from the distal end to the distal end from a longitudinal point that is approximately 4 to about 15 cm. 2. The proximal end of claim 1, wherein the proximal end defines a second orifice having a third diameter less than the second diameter, and the graft further includes a second taper zone between the proximal end and the first tubular zone. And the second tapered zone has a uniformly increasing diameter. 14. The apparatus of claim 13, further comprising a third tubular zone between the proximal end and the second tapered zone, wherein the third tubular zone defines a portion of a lumen having a uniform diameter corresponding to the third diameter. Vascular grafts. 15. The vascular graft of claim 14 wherein said second diameter is at least approximately 20% greater than said third diameter. 15. The vascular graft of claim 14 wherein said third diameter is less than approximately 6 mm. 15. The vascular graft of claim 14 wherein the first diameter is about 3.5 to about 4.5 mm, the second diameter is about 5.5 to about 6.5 mm, and the third diameter is about 3.5 to about 4.5 mm. 14. The vascular graft of claim 13 wherein the first tubular zone has a length that is at least approximately 60% of the graft length. The vascular graft of claim 13 wherein the first tubular zone has a length that is at least approximately 70% of the graft length. The vascular graft of claim 13 wherein the first tubular zone has a length that is at least approximately 80% of the graft length. The vascular graft of claim 13 wherein the first tubular zone has a length that is at least approximately 95% of the graft length. 10. The article of claim 1, comprising a cuff attached to an outer surface of the graft at least approximately 1 cm from the distal end, wherein the cuff is a wrappable seal inside the vessel wall for anastomosis. vascular graft defining a groove configured to receive a string suture. 23. The vascular graft of claim 22 wherein the groove is located on a plane that is approximately 45 degrees with respect to the longitudinal axis of the graft. 23. The vascular graft of claim 22 wherein the cuff is located approximately 1 to approximately 10 cm from the distal end. 23. The vascular graft of claim 22 wherein the cuff is located about 1 to about 5 cm from the distal end. The cuff of claim 22, wherein the cuff is A tubular member defining a lumen sized to engage an outer surface of the graft, And a first and second ridge extending around said member and defining a groove therebetween. The cuff of claim 22, wherein the cuff is A first ring member attached to the graft, A second ring member attached to the graft, And the first and second ring members define a groove therebetween. 28. The vascular graft of claim 27 wherein the first ring is located approximately 1.5 to approximately 2 cm from the distal end and the second ring is approximately 2 to approximately 2.5 cm from the distal end. 28. The vascular graft of claim 27 wherein the first ring is located approximately 1.75 cm from the distal end and the second ring is located approximately 2.25 cm from the distal end. Making an incision in the wall of the target blood vessel, Providing a vascular graft defining a lumen through which blood passes, The graft; A distal end adapted to be positioned within the blood vessel through the incision and defining a first orifice having a first diameter; Proximal end adapted to attach to the artery; A first tubular zone positioned between the distal end and the proximal end and defining a portion of a lumen having a uniform second diameter greater than the first diameter; And A first taper zone located between the first tubular zone and the distal end and having a gradually decreasing diameter, Inserting the distal end into the blood vessel through the incision such that the distal end passes to a downstream point of the incision; Securing the graft to the vessel wall; And grafting the proximal end of the graft to a desired target arterial site. 33. The method of claim 30, wherein said graft is secured to said vessel wall using a swatch suture. 32. The method of claim 31, wherein said bag closure is inserted into a wall of said target blood vessel prior to forming said incision. 31. The method of claim 30, wherein the step of inserting includes inserting the distal end into the blood vessel through the incision such that the distal end passes at least approximately 1 cm downstream of the incision. 31. The method of claim 30, wherein said blood vessel has a diameter of less than approximately 1.5 cm. 31. The method of claim 30, wherein said blood vessel has a diameter of less than approximately 1.4 cm. 31. The method of claim 30, wherein said blood vessel has a diameter of less than about 1.3 cm. 33. The method of claim 30, wherein said blood vessel has a diameter of up to approximately 3 cm. 31. The graft of claim 30 wherein the graft includes a cuff attached to an outer surface of the graft at least approximately 1 cm from the distal end, the cuff defining a groove configured to receive a bag closure for anastomosis, The inserting step includes inserting the distal end of the graft through the incision into the blood vessel such that the groove is positioned to receive the blood vessel wall, And the securing step comprises securing the vessel wall to the cuff. 39. The method of claim 38, wherein said vascular wall is secured to said cuff using a bag closure. 40. The method of claim 39, wherein the sachet suture is inserted into a wall of the target blood vessel prior to forming the incision, and the securing step includes pulling the sachet suture into the groove. The vascular graft of claim 1 wherein the graft comprises an externally detectable marking. The vascular graft of claim 1 wherein the cuff comprises an externally detectable indicator. 42. The vascular graft of claim 41 wherein the externally detectable indicator is a radiopaque marking. 42. The blood vessel graft of claim 41 wherein the externally detectable indicator comprises a material having a density different from that of the patient's body. 42. The vascular graft of claim 41 wherein the externally detectable indicator is a paint or a coating comprising an externally detectable substance. 42. The vascular graft of claim 41 wherein at least a portion of the cuff comprises an externally detectable substance. 33. The method of claim 30, wherein said graft comprises an externally detectable indicator. 39. The method of claim 38, wherein said cuff comprises an externally detectable indicator. Fixing the first end of the vascular graft to the first blood vessel, Anastomosis a second end of the graft into a second vessel; By removing the intermediate portion of the graft by cutting the graft at two locations between the first end and the second end, a second graft comprising the first end member and the second end including the first end is removed. Providing a member, Providing a tubular connector device defining a through lumen and having a first end segment configured to insert into the lumen of the first graft member and a second end segment configured to insert into the lumen of the second graft member; Connecting the first and second graft members to the first and second portions of the connector device. 50. The method of claim 49, wherein the connector device further comprises an intermediate segment configured to maintain the graft member ends in a spaced apart relationship. 50. The method of claim 49 wherein the segment or both segments of one of the first and second end segments are clipped, clamped to attach to one or both members of the first and second graft members. Or a vascular graft transplant method that defines a groove for receiving a tie filament. 50. The method of claim 49, wherein one or both segments of the first and second end segments are coated with an adhesive composition for attachment to one or both of the first and second graft members. . 50. The device of claim 49, wherein one or both segments of the first and second end segments receive clips, clamps or tie filaments for attachment to one or both members of the first and second graft members. A vascular graft transplant method comprising two rings defining a groove therebetween. 50. The device of claim 49, wherein one or both segments of the first and second end segments receive clips, clamps or tie filaments for attachment to one or both members of the first and second graft members. A vascular graft transplant method comprising a ring. 50. The method of claim 49, wherein one or both segments of the first and second end segments define a tapered end. 56. The method of any of claims 49 to 55, wherein the linking step comprises: Inserting the first portion into the lumen of the first graft member; Securing the second portion to the second graft member; Inserting the second portion into the lumen of the second graft member; Securing the second portion to the second graft member. A first end segment configured to insert into the lumen of the first graft member, A second end segment configured to insert into the lumen of the second graft member, A tubular connector device defining a through lumen comprising an intermediate segment configured to maintain the graft member ends in a spaced apart relationship. 59. The tubular connector device of claim 57, wherein one or both segments of one of the first and second end segments are coated with an adhesive composition to attach the segments to the first and second graft members. 58. The device of claim 57, wherein one or both segments of the first and second end segments receive clips, clamps or tie filaments for attachment to one or both members of the first and second graft members. Tubular connector device defining a groove. 58. The device of claim 57, wherein one or both segments of the first and second end segments receive clips, clamps or tie filaments for attachment to one or both members of the first and second graft members. A tubular connector device comprising two rings defining a groove therebetween. 58. The device of claim 57, wherein one or both segments of the first and second end segments receive clips, clamps or tie filaments for attachment to one or both members of the first and second graft members. Tubular connector device comprising a ring. 59. The tubular connector device of claim 57, wherein one or both segments of the first and second end segments define a tapered end. A first end segment configured to insert into the lumen of the first graft member, A tubular connector device defining a through lumen comprising a second end segment configured to insert into a lumen of a second graft member, Each of the first and second end segments define a groove for receiving a suture to attach the segments to the first and second graft members. 64. A tubular connector device according to any of claims 57 to 63, wherein said lumen of said connector device is straight.