Expandable intraluminal graft, and apparatus for implanting an expandable intraluminal graft.

DESCRIPTION

The invention relates to a graft or an expandable intraluminal prosthesis according to the preamble of claim 1 and an apparatus for implanting a graft or an expandable intraluminal prosthesis according to the preamble of claim 4.

It has been demonstrated through experimentation that intraluminal endobascular grafting represents a possible alternative to the clarosic vascular surgery. Intraluminal endovascular grafting involves the percutaneous insertion of a tubular prosthetic graft into a blood vessel and its displacement through a catheter to the desired point within the vascular system. Among the advantages of this method compared to conventional vascular surgery was the need to surgically expose, affect, remove, replace, or avoid the defective blood vessel.

WO-83/03752 advocates an intraluminal graft with the characteristics of preamble 1. Also, US-A4553545 describes a helical spring for application in blood vessels. These grafts of the prior art can generally be classified as self-expanding wires, where the graft, once driven to a stenootic point and released, is subjected to a helical or similar tension related to the construction of said grafts to enlarge and open the body duct outside.

The structures previously used as intraluminal vascular grafts include stainless steel spiral springs; coil springs made of thermosensitive expandable material; and expandable stainless steel elements made from zigzag stainless steel wire. In general, the above structures have a main drawback in common. To the extent that these structures have to be positioned at a desired point within a certain sunken body duct, when passing through the body duct there is no effective control of the final expanded configuration of each structure. For example, the expansion of a particular graft of the helical type is given previously by the spring constant and the elastic modulus of the concrete material used to make the structure of the helical spring. These same factors predetermine the degree of expansion of the collapsed elements formed from stainless steel wire in zigzag. In the case of grafts, or prostheses, intraluminaries, made of thermosensitive material that expands when heated, the degree of expansion is also given by the characteristics of the thermic expansion of the specific alloy used in the manufacture of the intraluminal graft.

Thus, once the previous types of intraluminal grafts have been expanded at the desired point within a body duct, such as an artery or vein, the expanded size of the graft cannot be varied. If the diameter of the desired body duct has been miscalculated, a graft lacking in size may not expand enough to contact the inner surface of the body duct, to fix it. In that case, it could move away from the desired point within the body duct. In the same way, an excess size graft could expand in such a way that the tension of the spring, or the force of expansion, exerted by the graft on the body duct, could cause the rupture of the body duct.

Another alternative to conventional vascular surgery has been percutaneous stenosis balloon dilatation, or elliptic vascular obstructions, by using an angioplastic balloon mounted in a catheter. In this procedure, the angioplastic balloon is inflated within the vessel or stenotic body duct in order to tonsure and dismember the components of the vessel wall to obtain an enlarged lumen. As for arteriosclerotic lesions, the relatively incompressible plaque remains unchanged, while the medial and adventitious myastic layers of the body duct stretch around the plaque. This procedure causes the dissection, or dissociation and tearing, of the layers of the wall of the body duct, where the intimate, or inner surface of the artery or body duct, undergoes a cracking. This dissection forms a "skirt" of underlying tissue that can reduce blood flow through the lumen, or obstruct the lumen. Usually, intraluminal dilatation pressure within the body duct can keep the dismembered layer or skirt in place. If the intimate skirt created by the balloon dilatation procedure against the expanded intima is not held, the intimate skirt can fold into the lumen and block it, or it can even detach and penetrate the body duct. When the intimate skirt blocks the body duct, surgery is necessary immediately to amend this problem.

Although the balloon dilation procedure is usually carried out in a hospital's catheterization laboratory, due to the previous problem, it is always necessary to have a surgeon on hand in case the intimate skirt blocks the blood vessel or body duct. In addition, due to the possibility that the intimate skirt will detach from the blood vessel and block the lumen, balloon dilatations cannot be carried out in certain critical body ducts, such as the left main coronary artery leading to the heart. If an intimate skirt formed by the balloon dilation procedure suddenly goes down to block a critical body duct, for example the left main coronary artery, the patient could die before being able to perform a surgical operation.

Other drawbacks related to balloon dilatation of elastic vascular stenoyses is that many fail due to the elliptical stealitic lesion recoil. This usually occurs due to a fibrochogenic content in the lesion and is sometimes due to certain mechanical characteristics of the area to be dilated. Thus, although the body duct can be initially expanded successfully by balloon dilatation, premature restonoísis may occur later due to re2

020 502 fragment of the wall of the body duct, which reduces the size of the previously expanded lumen of the body duct. For example, it is known that stenosis of the renal artery in the ostium is related to balloon dilation because dilatation forces are applied to the wall of the aorta instead of the renal artery itself. Vascular stenosis caused by neointimal fibrosis, such as those seen in the dialysis access fistulas, have been shown to be difficult to dilate, requiring high dilatation pressures and greater deglobo diameters. Similar difficulties have been observed in angioplasts of anastomotic strictures of artery graft and recurrent stenoisis of postendarterectomy. The percutaneous angioplast of Takaysu arteritis and arterial stenosiosis of neurofibromatosis may have a poor initial response and reappear what is believed to be due to the fibrotic nature of these lesions.

Thus, an object of the invention is to provide a graft, or a prosthesis, such as the one mentioned in the preamble of claim 1 and a corresponding apparatus that can be inserted through controlled expansion so that it fits properly to the body duct.

This objective is achieved with the characteristics set forth in claims 1 and 4.

According to the invention, the above advantages are achieved with the present expandable intraluminal vascular graft. The present invention includes a tubular shaped element with a first and a second end and a wall surface disposed between both ends, whose wall surface was formed by a plurality of intersecting elongated elements, some of whose elongated elements intersect each other. both first and second ends of the tubular element; the tubular element has a first diameter that allows the intraluminal positioning of said tubular element to a body duct with a lumen; and the tubular element has a second expanded diameter, after the application of a force from inside the tubular element that projects radially outward, whose second diameter is susceptible to variation, following the amount of force applied to the tubular shaped element, whereby the tubular element can expand to expand the lumen of the body duct.

Accordingly, prior to the development of the present invention, there was no expandable intraluminal vascular graft, and method and apparatus for expanding the lumen of a body duct, which: prevents the reappearance of stenoisis in the body duct; can be used for critical body ducts, such as the left main coronary artery of a patient's heart; prevent recoil of the body duct wall; and allow the intraluminal graft to expand to a variable size to prevent displacement of the graft from the desired point; and to prevent the rupture of the body duct by the expanded graft. Thus, the technique has sought an expandable intraluminal vascular graft, and method and apparatus for expanding the lumen of a body duct that: prevents the reoccurrence of stenoisis in the body duct; It is believed to be used for critical body ducts, such as the left main coronary artery of the corazoin; prevent recoil of the body duct; and can be expanded to a variable size within the body duct to prevent displacement of the graft from the desired point; and to prevent the rupture of the body duct by the expanded graft.

Another feature of the present invention is that the plurality of elongated elements can be a plurality of wires, and the wires can be secured together where the wires intersect with each other. Another characteristic of the present invention is that the plurality of elongated elements may be a plurality of thin bars that secure each other where they intersect. And yet another characteristic of the present invention is that the tubular shaped element may be provided with a biologically inert coating on the surface of its wall and that that coating may carry a means for anchoring the tubular element to the body duct.

According to the invention, the above advantages are also achieved with the present method of expanding the lumen of a body duct.

The method of the present invention comprises the following steps: inserting an intraluminal graft, arranged on a catheter, into the body duct by moving it to a desired point within the body duct; and expanding a portion of the catheter so that the intraluminal graft expands radially outwardly until it contacts the body duct until the lumen of the body duct at the desired point of such duct has expanded, thereby preventing the intraluminal graft from sinking the body duct and the size of the expanded lumen is reduced.

Another feature of the present invention is that the portion of the catheter that was in contact with the intraluminal graft can be sunk, and the catheter removed from the body duct. Another feature of mine of the present invention is that a catheter with an expandable and inflatable portion associated therewith can be used; and the expansion of the intraluminal graft and the portion of the catheter is achieved by swelling the expandable and inflatable portion of the catheter.

Another feature of mine of the present invention is that a metalic fabric tube can be used as an intraluminal graft, whose metal fabric tube has a first predetermined depressed diameter that allows the tube to be introduced into the body duct and positioned at the desired point . And another feature of the present invention is that the metalic fabric tube can be expanded to a second diameter within the body duct; whose second expanded diameter is variable and is determined based on the desired expanded internal diameter of the body duct, whereby the expanded metal fabric tube could not move from the desired point within the body duct and the expansion of the intraluminal graft does not cause the rupture of the body duct

In accordance with this invention, the above advantages are also achieved through the pre3

020 502 sente apparatus to reinforce a body duct intraluminarily. The present invention includes: an expandable tubular prosthesis with a first end and a second end and a wall surface disposed between both first and second ends, whose wall surface is formed based on a plurality of elongate intersecting elements; and a catheter, with an expandable and inflatable portion associated therewith and that includes a means for assembling and retaining the expandable tubular prosthesis on the expandable and inflatable portion, thereby swelling the expandable and inflatable portion of the catheter, the prosthesis It is forced radially outwardly into contact with the body duct. Another feature of the present invention is that the mounting and retaining means can comprise an annular retaining element disposed on the catheter adjacent to the expandable and inflatable portion and adjacent to each end of the expandable and tubular prosthesis.

The expandable intraluminal vascular graft, the method for expanding the lumen of a body duct, and the apparatus for reinforcing an intraluminarily body duct of the present invention, when compared with intraluminal grafts, methodologies for implanting them, and the balloon dilatation technique of the proposed prior art, they have the following advantages: prevention of the recurrence of stenoosis; it is believed that it allows implantation of grafts in crotic body ducts, such as the left main coronary artery of the corazoon; prevention of recoil of the body duct wall; and allow the expansion of the intraluminal graft to a size that varies according to the conditions of the body duct.

In the drawings:

Figure 1A is a perspective view of a graft, or a prosthesis, intraluminal vascular for a body duct, with a first diometer that allows graft positioning, or prosthesis, in the body duct;

Figure 1B is a perspective view of the graft, or prosthesis, of Figure 1A, in its expanded configuration disposed within a body duct;

Figure 2A is a perspective view of another embodiment of a graft, or an expandable, intraluminal vascular prosthesis for a body duct, with a first diameter that allows intraluminal positioning of the graft, or the prosthesis, in the body duct; Y

Figure 2B is a perspective view of the graft, or prosthesis, of Figure 2A, depicted in its expanded configuration disposed within a body duct.

Although the invention will be described in relation to its preferred embodiment, it should be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is proposed to cover all alternatives, modifications or equivalences that may be included within the spirit and scope of the invention, as defined in the appended claims.

Figures 1A and 1B illustrate an expandable intraluminal vascular graft or expandable prosthesis for a body duct, 70. It should be understood that the terms "expandable intraluminal vascular graft" and "expandable prosthesis" are used interchangeably to some extent when describing this invention, since the methods, apparatus, and structures of the present invention can be used not only in relation to a graft. expandable intraluminal vascular to expand partially clogged segments in a blood vessel, or body duct, They can also be used for many other purposes as an expandable prosthesis for many other types of body ducts. For example, expandable prostheses 70 may also be used for purposes such as:

(1) placement of support grafts within open blocked arteries by transluminal recanalization, but which could very possibly sink in the absence of an internal support;

(2) similar use after passage of the catheter through mediastinal veins or other obstructed by canons that cannot be operated; (3) reinforcement of intrahepatic communications created with catheter between the portal and hepatic veins in patients suffering from hypertension in the portal;

(4) placement of support grafts in the narrowing of the esophagus, intestine, ureters, urethra; and (5) reinforcement with support grafts of blocked bile ducts. Accordingly, the use of the term "prosthesis" encompasses the previous uses within the different types of body ducts, and the use of the term "intraluminal vascular graft" encompasses the use to expand the lumen of a body duct. Likewise, in this sense, the term "body duct" encompasses any existing duct within the human body, as described above, as well as any vein, artery or blood vessel within the human vascular system.

Following Figure 1A, the graft, or the prosthesis, intraluminal vascular, 70, is generally depicted as a tubular shaped element 71 with first and second ends, 72, 73, and a wall surface 74 disposed between both first and first ends. second 72, 73. Preferably, the wall surface 74 was formed based on a plurality of elongate elements 75, 76 intersecting with each other between the two first and second ends 72, 73 of the tubular element 71, as illustrated in the intersection points 77. The tubular element 71 has in the first diode, d, which will be described in detail below, which allows the intraluminal positioning of the tubular element 71 within a body duct provided with a lumen. Turning to Figure 1B, once a radial force extending outwardly applied, which was described in detail below, has been applied, the tubular element 71 has a second, expanded, diameter d ', whose second diameter d' can vary in size according to the amount of force applied to the tubular shaped element 71.

In Figures 1A and 1B, the elongate elements 75, 76 that form the wall surface 74 of the tubular element 71, can be made from any material that is indicated and is compatible with the human body and body fluids (which is not show) with those who

020 502 can bump the graft, or the prosthesis, vascular 70. The elongate elements 75, 76 must also be manufactured based on a material provided with the strength and elasticity characteristics necessary to allow the tubular element 71 to expand from the configuration shown in Figure 1A to the configuration shown in Figure 1B and also allow the tubular element 71 to maintain its expanded configuration with the enlarged diameter d 'shown in Figure 1B. Among the materials indicated to manufacture the tubular element 71 would be silver, tantalum, stainless steel, gold, titanium, any suitable plastic material with the necessary characteristics mentioned above. Preferably, the elongate elements 75, 76 illustrated in Figures 1A and 1B are stainless steel wires of cylindrical section. Of course, it should be understood that each elongate element 75, 76 could have other sectional configurations, such as triangular, square, rectangular, hexagonal, etc. Likewise, it is preferable that the plurality of elongate elements 75, 76 intersect each other, as at the intersection points 77. The elongate elements 75, 76 could be secured together in any conventional manner, such as welding, tin welding, or glue, such as with a suitable epoxy glue; however, it is preferable that the intersection points 77 are welded with silver. By securing the elongate elements 75, 76 together, it is achieved that the tubular element 71 has a relatively high resistance to radial sinking, and that the tubular element 71 can maintain its enlarged diode, d ', as shown in Figure 1B. It is preferable that the tubular element 71 is manufactured based on continuous stainless steel wire woven in an interwoven manner to form what could be termed generically a tube of metal fabric.

When fabricating the tubular element, or the metal cloth tube, 71, it can initially be manufactured with the configuration shown in Figure 1A with the diameter, d. On the contrary, it can be manufactured with a diameter larger than the initial diameter d, once it has been manufactured, carefully lower the tubular element 71 to the diameter d shown in Figure 1A. When lowering the tubular element, or tube of metallic fabric, 71, care must be taken to ensure that the adjacent elongated element 75, 76 is not avoided. Of course, it should be understood that by expanding the tubular element, or tube of metallic fabric, 71 , until the configuration shown in Figure 1B, the distance between the first and second ends 72 and 73 was evidently reduced.

Figures 2A and 2B illustrate another embodiment of the expandable intraluminal vascular graft, or prosthesis. The same reference numbers are used, applicable to the elements described above in Figures 1A and 1B. The intraluminal vascular graft, or prosthesis, 70 of Figures 2A and 2B differs from that described above in Figures 1A and 1B, in that the plurality of elongate elements 75 and 76 are a plurality of thin bars 78, 79 that are preferably secure each other at the points where bars 78, 79 intersect with each other. It is preferable that the bars 78, 79 have a thin rectangular sectional configuration, and can be joined together by any conventional method, such as welding, brassing, welding with tin, or they can be formed jointly. It is preferable that the tubular element 71 is initially a thin-walled stainless steel tube, and that the openings 82 between the intersecting bars 78 and 79 be formed by a conventional method of selective erosion, for example electromechanical or laser erosion, with which the resulting structure is a tubular element 71 with a plurality of elongate intersecting elements 78, 79. The implementation of the graft, or prosthesis, 70 of Figure 2A may also assume an expanded configuration as shown in Figure 2B and as previously described in relation to Figure 1B, after application from inside the tubular element 71 of a radial force projecting outward. Likewise, it should be understood that the realization of the vascular graft, or prosthesis, 70, of Figures 2A and 2B could also be described generically as a tube of metalic fabric.

The methods and apparatus of the present invention will be described in detail. Once more, it should be understood that the methods and apparatus of the present invention no longer serve only to expand the lumen of a body duct, such as an artery, vein, or blood vessel of the human vascular system, but also serve to carry Perform the procedures described above to intraluminarily reinforce other body ducts or channels, as described. An expandable intraluminal vascular graft, oprotic, 70, which may be of the type previously described in Figures 1A or 2A, is disposed or mounted on a catheter. The catheter is provided with an expandable and inflatable portion associated therewith. The catheter has a means to mount and retain the expandable intraluminal vascular graft, or prosthesis, 70, in the expandable and inflatable portion, 70, of said catheter.

It is preferable that the mounting and retention means consist of annular retaining elements arranged in the catheter adjacent to the expandable and inflatable portion of the catheter; and an annular retaining element disposed adjacent each end 72, 73 of the intraluminal vascular graft, or prosthesis, 70. It is preferable that as long as the annular retention elements are in solidarity with the catheter and the annular retention element adjacent to the tip of said catheter has an upward slope away from said catheter tip in order to protect and retain the graft, or prosthesis, 70 as it is introduced into the lumen of the body duct, as described in detail below, the other annular retaining elements have a downward slope away from said tip of the catheter to ensure easy removal of said catheter from the body duct. Once the expandable intraluminal graft, or prosthesis, 70, is disposed on the catheter as described above, the graft, or prosthesis, 70, and said catheter are introduced into a body duct by catheterization.

020 502 of the body duct, conventionally.

Conventional placement of the catheter and graft, or prosthesis, 70 is carried out in the desired position of the body duct where it is desired to expand the lumen of the body duct 80 by intraluminal graft 70, or where it is desired to implant the prosthesis, 70 Fluoroscopy or any other conventional technique can be used to ensure that catheter 83 and graft, or prosthesis, 70 are positioned at the desired point within the body duct. Next, the prosthesis, or the graft, 70 is expanded by expanding the expandable and inflatable portion of said catheter, whereby the prosthesis, or the graft, 70, is projected radially outwardly to contact the body duct. In this sense, the expandable and inflatable portion of said catheter can be a conventional angioplast balloon.

After performing the desired expansion of the prosthesis, or graft, 70, said angioplastic balloon can be folded down, or deflated, and the catheter can be removed in a conventional manner from the body duct.

If desired, the catheter with the graft, or the prosthesis, 70 disposed thereon, may be initially wrapped in a Tefloon sheath, which is detached from the prosthesis, or the graft, 70, before the expansion of the prosthesis , or the graft, 70.

It should be meant that the tubular element 71 of the prosthesis, or the graft, 70, initially has the predetermined diode d depressed as described in relation to Figures 1A and 2A, in order to allow the introduction of the metal fabric tube , or tubular element, 71, in the body duct, as described above. When it is desired to implant the prosthesis 70 into a body duct for the purposes described above, the metal cloth tube, or the prosthesis 70 expands to the second diode d ', and the second expanded diode d' is variable and is determined by the internal diameter of the body duct 80. Accordingly, the expanded prosthesis, 70, when the angioplastic balloon was deflated, could not move away from the desired position within the body duct, 80, nor was it likely that the expansion of the prosthesis 70 caused a rupture of the body duct.

When it is desired to use an intraluminal graft, 70, to expand the lumen of a body duct with an area of ​​stenosis, the expansion of the intraluminal vascular graft, 70, by means of the angioplastic balloon, allows controlled dilatation of the stenootic area and, at the instead, controlled expansion of the vascular graft, 70, whereby the vascular graft, 70, prevents the body duct from sinking and reducing the size of the previously expanded lumen.

Once more, the second expanded diameter d 'of the intraluminal vascular graft, 70, is variable and is determined by the expanded internal diameter of the body duct. Thus, the expandable intraluminal graft, 70, did not shift from the desired positioning within the body duct when the angioplast balloon was deflated, nor was it likely that the expansion of the intraluminal graft, 70, caused the rupture of the body duct. Likewise, in case of forming an onset skirt, or a fissure, in the body duct at the point where the graft is located, 70, the graft, 70, guaranteed that such an intimate skirt cannot be folded into the body duct, nor detached and move through the body duct. In the situation in which the graft is used, 70, in the manner described above, to expand the lumen of a portion of the left main artery, it is believed that the last skirt could not penetrate the heart, causing death to the patient .

As it is only necessary to swell said angioplastic balloon once to expand the graft, 70, it is believed that a greater amount of endothelium, or innermost layer of the intima, or internal surface of the body duct was preserved, since the degree of endothelial denudation during the transluminate angioplast is related to the balloon inflation time. In theory, in theory, the amount of preserved endothelium should be large since in the expanded graft configuration, 70, potentially the endothelium is exposed through graft openings, 70. Astronomy is believed, that intact areas of endothelium between elongated elements 75, 76, 78, 79 of the graft, 70, can produce a multicentric endotheliolization model such as experimental studies show.

It should be understood that the invention is not limited to the exact details indicated and described with respect to construction, operation, exact materials or realization, since the modifications or equivalences would be obvious to those skilled in the art. For example, the means of expanding the prosthesis or graft could be a plurality of logic elements arranged in a catheter and hydraulically activated, or a plurality of angioplastic balloons could be used to expand the prosthesis or graft. Accordingly, the invention should be limited only by the scope of the appended claims.

020 502