Self-expanding stent for introducing a medical device in a body cavity and manufacturing process

p0001The present invention relates to a self-expanding medical device guardian for introducing into inne cavity of a human or animal body, comprising a radially expandable and contractible tubular body between a first diameter, corresponding to a working condition of the guardian, and a second diameter greater than the first, corresponding to a guardian resting state, and axially expandable and retractable between inne first length, corresponding to the working state, and a second smaller length has the first, corresponding to the state of rest , this tubular body comprising first flexible rigid son wound in a first direction about a longitudinal axis of the tubular body, and second flexible rigid son wound in a second sense opposite the first about the longitudinal axis aforesaid, each said wound in a son said directions crossing wound in the other direction according braided innate disposition, son of the above care may arise in the form of at least a multiple caused.

p0002It has long been known that tutors are used as vascular stents, esophageal or other (GB-1205743). These tutors formed of a tubular braid of individual son comprise, in the rest state, son of forming a relatively small angle to inne generatrix of the tube, that is to say a maximum of 30 °. The guardians of this kind do not offer a sufficient radial expansion capacity when released after being radially compressed. Their compressive strength is also insufficient when used in body cavities whose walls have a high radial pressure on the tutor introduced.

p0003therefore it has been sought to remedy these drawbacks by providing a braiding of individual son at a greater angle so that the guardian of the idle state, the son have an angle greater than 45 °, preferably of at least 60 ° with respect to a generatrix of the guardian (US-a-4,655,711 and US-a-4,954,126). However, tutors large braiding angle of great disadvantage. Indeed, the tubular stent to be elongated by 2 to 3 times its original length to be inserted into a vascular introducer. It then occupies 40 to 50% of the length of the latter, by stiffening the complicated and making its passage through the femoral artery through which the introduction into the body is generally initiated. During release, the tubular structure collapses, two to three times in length. It is therefore very difficult to estimate the length that will be deployed in the internal cavity of the body treated and the precise location where the tutor will be anchored, which can cause serious problems. For example, a stent length can extend beyond a vessel bifurcation and thereby cause an undesirable artery closure, when the guardian is covered with a coating, as is the case for the luminal stent. In another case, if the extended length is too short, the aneurysm treaty will not be closed. Finally, it appeared that tutors wide angle braiding and individual son did not have good resistance to blood pressure within the treated aneurysms. Inside the aneurysm, that is to say where the stakes do not undergo more radial compression from the vascular wall, the latter tend to bulge, which promotes sealing losses.

p0004Other tubular braids based son, which are used in devices to be introduced into the human body, are also described in particular in EP-A-0183372, US-A-3509883, US-A-5061275 and US-A 5171262.

p0005In US-A-5061275, in particular, there is provided the possibility to shape the braided tubular body whose ends flare conically relative to the rest of the body which is cylindrical in shape. Without solving the problem of bloating cited in aneurysms, the guardian of the embodiment allows only limited adjustment of the length if treated. As soon as the surgeon cuts an excessive length of one end, for example, a stent provided with such a guardian, this end shows no flaring and lost the advantage conferred by the latter.

p0006Finally, known as tutors expandable tubular braids for prostheses designed to deliver drugs within the vascular system (WO 91/12779). According to one embodiment described herein, the braided filaments are in the form of a multiple thread, three filaments being twisted together respectively in a strand to form the multiple thread. For the average skilled person, it is clear that such an embodiment is impractical. It will introduce a congestion unbearable volume and crossover point between the strands it will produce significant friction. Finally, because of these strands, it will be difficult to sufficiently reduce the guardian of the diameter can be inserted into an introducer. If metal filaments, they will suffer enormously and a case is not excluded.

p0007During son braid of stranded manufacturing trials, it was observed that, during the heat treatment the twisted structure contained particles that remained trapped inside thereof, very difficult particles to be extracted, even by ultrasonic cleaning . However, the cleanliness of the structure that will be in contact with the blood is of utmost importance, and these particles can affect the biocompatibility of the stent.

p0008According to the invention one has solved the problems mentioned above by a self-expanding guardian as described at the outset, wherein each said multiple wire comprises the aforesaid flexible rigid son, which are arranged side by side the at least two following a parallel course in the braided arrangement. Such guardian has a high dimensional and geometric stability, without requiring large braiding angle and, thereby, the precision release this guardian is greatly increased. Moreover, one can easily reduce the diameter of such a guardian to that of a current feeder, multiple son used according to the invention having no obstacle to this.

p0009Advantageously all the aforesaid first son and all the aforesaid second son of the above form multiple son.

p0010For self-expanding guardian is understood that the invention, brought into its working position, that is to say an axially compressed and radially expanded position, guardian, once released, tends to spontaneously recover its position rest, that is to say a radially expanded position and axially contracted.

p0011In the braided disposal son, in some embodiments, a first multiple wire goes, at a crossing with a second multiple wire, get over it and at the next crossing pass below the second then crossed over , And so on. In other embodiments, the first multiple wire passes over a second twine two successive crossings or more and then pass only below a second multiple wire after several successive crossings and so on. Mixed braided provisions may also be provided, as well as braids partially formed son double and monofilaments.

p0012Anyway, multipath son according to the invention is meant that the flexible rigid son, that form, are arranged side by side and follow a parallel course in the braided arrangement. From the moment two neighbors son no longer follow the same route, that is to say for example that one crosses a reverse direction wound wire passing over while the other crosses that same coiled wire reverse passing underneath, this is more than a multiple wire forming son within the meaning of the present invention. The son even forming a multiple thread can be joined or arranged at very short distance of each other.

p0013A medical device to be introduced into a cavity of a human or animal body, means for example luminal stents, catheters, stents, grafts and the like which may be introduced for example into the vascular cavity, esophageal, bladder, ureteral, biliary, and other tubular ducts of the body.

p0014According to a particular embodiment of the invention, at least one of its ends, the tubular body formed of multiple braided son has, in its resting state, a flaring where multiple son follow a spatial spiral with increasing radii. Such embodiment is particularly advantageous for the treatment of aortic aneurysms for example, where there occurs a shrinkage of the neck of the proximal or distal aneurysm. The following guardian the invention, in particular its tapered end, has a crush strength by the arterial wall due to the narrowing of the collar. The radial expansion of the flared portion guardian also promotes the absence of migration along the wall of the cavity which it must be applied.

p0015It is provided, according to a very advantageous embodiment of the invention, a flare at the end of the stent, the generatrices terminate in hyperbola. As discussed later, this embodiment has the advantage of great simplicity of manufacture and perfect reproducibility of the braiding angle.

p0016There is also provided, according to the present invention, that the tubular body comprises guardian in the state of rest, two flared ends of large diameter and, therebetween, a cross section of the tubular body of small diameter and that, from each of the flared ends to the small-diameter section, the tubular body presence in cross section a diameter decreasing continuously. For this embodiment, the guardian opposes any bloat inside an aneurysm while preserving its good bonding properties by its flared ends, when dropping into a tubular cavity of a human body or animal. And that, even if the surgeon is reduced by cutting a part of the length of the tutor. The new formed end still flared from the rest of the guardian. Finally, the radial expansion of the flared portions of the guardian is maintained during the release, and the flared portions, perfectly matching the shapes of the vessel walls where they are dropped effectively prevent migration of the guardian along these walls.

p0017There is provided, according to an advantageous embodiment of the invention, that, for at least one of the flared ends and the cross section of small diameter, the tubular body includes a generatrix in the shape of right. According to a preferred embodiment of the invention, between at least one of the flared ends and the cross section of small diameter, the tubular body includes a generatrix in the form of half-hyperbola. In this case, the guardian has a form of hyperboloid. According to another embodiment of the invention, between at least one of the flared ends and the cross section of small diameter, the tubular body includes a generatrix in the shape of a circular segment.

p0018In the resting state, the tubular body preferably comprises multiple son oriented at an angle, preferably less than, 45 ° with respect to one of its generatrices. According to the invention, the braiding angle does not need to be high to obtain good properties of dimensional stability. Therefore, it follows a significant improvement guardian of dropping into the cavity where it should be applied.

p0019According to another advantageous embodiment of the invention, the tubular body has an outer wall surface and an inner wall surface and comprises on at least one of these two wall surfaces an expandable coating. Such recovery may be applied to the guardian according to any known technique, for example according to the teaching of EP-A-0603959. This allows for example to form luminal endoprostheses 40 mm diameter at rest which recovery is made of polycarbonate-urethane or other fibers with a fiber diameter of 10-20 microns. The diameter of such stents may then be reduced to a diameter of 4 to 5 mm for insertion into an introducer. It is understood that the recovery may be of a different nature and can be achieved by other well known techniques, without departing from the scope of the invention.

p0020The invention also relates to a medical device to be introduced into a cavity of a human or animal body which comprises a self-expanding guardian according to the invention.

p0021There is also provided according to the invention a method of preparing a self-expanding medical device guardian for introducing into a body cavity, comprising a braiding son from time interleaved counter-rotating, so as to form a radially expandable and contractible tubular body between a first diameter, corresponding to a working condition of the guardian, and a second diameter greater than the first, corresponding to a guardian of the idle state, and axially expansible and retractable between a first length, corresponding to the working state, and a second length shorter than the first, corresponding to the rest state, braiding comprising a winding of first flexible rigid son in a first helical direction around a longitudinal axis of the tubular body and a winding of second flexible rigid son in a second helical direction opposite to the first, each wire wound in a helical direction of said crossing multiple son wound in the other helical direction, the aforementioned son can be in the form of at least one multiple thread .

p0022It has long been known in the field of cable manufacture of tubular braids formed of metal son. The issues in this area are, however, totally different and the demands on the braids in cable are quite distinct. A self-expanding stent braiding process is mentioned in US-A-5061275.

p0023According to the invention it is anticipated that the method described above comprises, prior to braiding, a coiling of at least one time by the aforesaid son arranged next to the at least two, to form said at least one wire multiple, and, during winding, the son forming a multiple wire follow a parallel course.

p0024Such a process allows the production of a much more efficient as guardian of the prior art, without having to modify existing equipment, so no additional investment. It does not include either a preliminary step of manufacturing a multifilament, such as a strand, for example.

p0025According to a particular embodiment of the invention, the method comprises a braiding of the tubular body at a diameter greater than the aforementioned second diameter, axial expansion of the plaited tubular body, in particular by introducing it into a predetermined shape inner tube, and a hardening heat treatment of the tubular body thus axially expanded to secure it so that, after this treatment, it is in the idle state when it has a shape corresponding to that of the internal cavity of the tube. This embodiment provides the angles between the son and a generator of reproducible guardian after the tubular body fixing step in form corresponding to the state of rest. The tube may have any suitable shape, for example cylindrical cavity or hyperboloid.

p0026According to an improved embodiment of the invention, after introduction of the plaited tubular body in said tube, at least one of its ends protrudes from the tube, which widens. Thus, after the heat treatment of the aforementioned curing, the guardian may be fixed in the state of rest, with a widening at least at one of its ends. In this embodiment, the flare in question can automatically take such a form that includes a generator in the form of hyperbole segment.

p0027According to yet an embodiment of the invention, the method comprises, after braiding, a threading of the tubular body woven around a suitably shaped mandrel, a voltage at the ends of the tubular body to apply it onto the mandrel, a hardening heat treatment of the tubular body thus axially tensioned to fix it so that, after this treatment, it has in the rest state the shape of the mandrel.

p0028Further details and features of the invention are set forth in the appended claims.

p0029The invention will now be described in more detail in the following description of non limiting embodiments and with reference to the accompanying drawings.

p00301 shows a side view of an end portion of one embodiment of self-expanding guardian according to the invention.

p00311A shows, on an enlarged scale, a detail of the braiding multiple son guardian of Figure 1.

p00322 shows a side view of an end portion of a second embodiment of the invention following guardian.

p00333 shows a side view of an end portion of a third embodiment according guardian embodiment the invention.

p00344 shows a side view of a fourth embodiment self-expanding guardian according to the invention.

p00355 shows a side view of a fifth embodiment according guardian embodiment the invention.

p00366 shows a side view of a sixth form of embodiment according to tutor the invention.

p00377 shows a general diagram of the braiding apparatus and Figure 8 a detail view of the braiding operation.

p00389 shows a partial view of a guardian to the invention the end of production.

p0039In the various figures, identical or similar elements bear the same references.

p0040As is apparent from Figure 1 the self-expanding guardian according to the invention, illustrated partially, is formed by a tubular body 1 having at the end illustrated a cylindrical shape. The tubular body 1 is formed of braided son. It comprises first flexible rigid son, for example 2 and 3, which are arranged side by side, here two in number, and which thus form multiple first son wound in a first helical direction around the longitudinal axis 4 of the body tubular.

p0041It also comprises second rigid son 5 and 6 which are arranged side by side, here two in number, and which thus form multiple second son wound in a second helical direction opposite the first. Obviously we can provide three, four or more son arranged side by side to form a multiple thread according to the invention (see, eg, Figure 5). Note also that the son arranged side by side to form a multiple thread are contiguous over almost their entire length. It is only for reasons of clarity and readability of the drawings that the son forming a multiple thread, as the son 2 and 3 or 5 and 6 respectively, are shown slightly spaced from one another.

p0042As can be seen in Figures 1 to 3, multiple son of the tubular body 1 intersect at a braided arrangement, the braiding method can be variable as already indicated above. It appears particularly in Figure 1A, all hoses son even forming a multiple thread within the meaning of the invention follow a strictly parallel course in the braid.

p0043Multiple son used consist of any material which is suitable for introduction into the human and animal body and which has a sufficient rigidity and flexibility for producing a self-expanding guardian. For example can be provided stainless metal son, biocompatible. Such son meets the standards ISO 5832/7 and / or ASTM F1058-91 are highly desirable. PHYNOX the son can be made, for example to the AFNOR designation: K13 C20 N16 FE15 C7, marketed by the firm Sprint Metal, Paris, France. It is understood that other son metal lic son or of other materials, such as elastic memory plastics can be used.

p0044In Figure 1, the tubular body is shown in the rest state. In this state it presents, in this embodiment, a diameter D of approximately 28 mm. Its length is chosen according to the use of the tutor. In its working state, that is to say when it will be introduced in a known introducer, not shown, the guardian must present a diameter of up to 3 to 4 mm. The working condition is obtained by radial compression of the guardian and / or by moving the ends of the guardian in the axial direction. In the working state, the guardian therefore has a length greater than its length in the resting state. The arrangement of the multiple son following the invention in any way encumber obtaining this work state guardian.

p0045In this rest state, the son present, in the embodiments illustrated with respect to a generator (7 in Figure 2) guardian an angle at most 45 °, preferably less than one. This offers the great advantage that the tutor, the working state, inserted into its introducer, not excessive length with every drop that raises drawbacks, as already indicated above. Such an angle of 45 °, but is not critical to the invention and may in the circumstances be exceeded.

p0046As can be seen in Figure 1, the tubular body 1 may be coated on its inner surface an 8 shown partially overlap. This covering may be any suitable biocompatible material, in particular for the manufacture of luminal endoprostheses (see EP-A-0603959). A covering on the outer surface may be provided instead of the inner cover 8 or simultaneously thereto. The use of multiple son according to the invention further offers the advantage of a relatively large contact area for better adhesion with such a covering.

p0047In Figure 2, illustrates a guardian following the invention, the tubular body 1 at one end flaring 9. As we can see, at this point, multiple son follow a spatial spiral increasing radii. In this embodiment, the generator 7, in place of the hollow 9, forms a straight line which gradually deviates outwardly from the axis 4. The hollow 9 here is of frustoconical shape.

p0048In Figure 3 is illustrated a guardian which the tubular body 1 has at one end a taper 10 whose generatrix has the shape of hyperbola segment. This widening results in an end 10 of the guardian 1, in form of truncated hyperboloid.

p0049As is apparent from Figure 4, the self-expanding guardian according to the invention is formed of a tubular body 1 having in this example a form of hyperboloid.

p0050In Figure 4, the tubular body 1 is shown in the rest state. In this state it presents, in this embodiment, a first flared end 11 of diameter D₁ and a second flared end 12 of diameter D₂ equal to D₁. Halfway between the two flared ends is located a transverse section 13 of the tubular body whose diameter D₃ is less than D₁ and D₂. The diameter D₃ may for example be about 28 mm, and the diameters D₁ and D₂ for example equal to 58 mm. Between each flared end 11 or 12 and the cross section 13 of smaller diameter, the tubular body 1 has, in cross section, a diameter which decreases continuously. In the case illustrated this decrease is such that the tubular body comprises a generator 7 in the form of a hyperbola.

p0051In the resting state, the son present, in this illustrated embodiment, compared to a 7 of generating a guardian angle α which varies constantly. In its central part, this angle is preferably at most 45 °, preferably less than this value. The flared ends it is obviously much larger. This offers the great advantage that the tutor, the working state, inserted into its introducer, not excessive length with every drop that raises drawbacks, as already indicated above. Moreover, the radial expansion of the ends is excellent and provides good adhesion of the guardian, by preventing migration thereof during or after release.

p0052In Figure 5, there is illustrated a tutor according the invention, the tubular body 1 has a first flared end 11 of diameter D₁ and a second end 12 of diameter D₂ less than D₁. The cross section 13 of small diameter D₃ is here located at a shorter distance from the end 12 than the end 11, which gives rise to a tubular body of asymmetric form. Between each flared end 11 or 12, and the cross section 13 of smaller diameter, the tubular body includes a generatrix in the shape of right, which gradually deviates outwardly from the longitudinal axis 4, which gives rise to a truncated form of diabolo. In this embodiment, the multiple braided son in a helix at increasing radii are shown in a partially broken. Here each multiple thread has 3 son arranged side by side.

p0053In Figure 6, illustrated is a guardian which the tubular body 1 has between its ends a flared generator in form of a circular segment.

p0054Obviously we can provide a range of other generators to achieve a guardian according to the invention, such as a segment of an ellipse, an oval, a hypocycloid, parable, of catenoid, and similar curves.

p0055It should be understood that the generators of each side of the cross section of small diameter may be of different nature and value.

p0056The embodiments of the invention illustrated in Figures 2-6 offer the great advantage of secure mounting guardian upon deployment without further migration into the cavity. The attachment to the wall of the latter is more intensely at the end which is the first dropped, thanks to its flared shape, and this restrains the device dropped in the position that we have imposed. A tutor according to such the invention, having two flared ends, is very advantageous in particular during the introduction of an endoprosthesis for treating an abdominal artery aneurysm. Both ends conform to the shape of the collars of the aneurysm thereby retaining perfectly the stent, which is subjected to this location to the demands of the blood pressure. The central part of the tutor according to Figures 4-6, bent inward and recalled in this sense, is resistant to the pressure inside the aneurysm, where no more radial compression is exerted on the walls by the tutor vascular.

p0057Tutors according to Figures 2 to 6 are also quite suitable for the treatment of arterial aneurysms subclavian, where the tutor can be strongly bent at one end. Instead of crashing by closing this end, as the cylindrical guardians of the prior art, the tutor stays in a wide open position at the end, thanks to the shape thereof.

p0058A disconnecting the stent, and therefore its guardian, the surgeon for a cut to length just before the treatment is safe because the flared ends that remain despite cutting last minute. storage problems of varying lengths stents are thus solved.

p0059The manufacture of a braided tubular body has long been known in the art of cable manufacture and use is made here of this technique is illustrated in Figures 7 and 8 appended. In Figure 7, a support cable 14 is unwound from a coil 15. A guidance system, designated generally by reference 16, guide and bring this power cable 14 which then passes through the braiding machine 17 schematically right here. It comes out of the machine, provided with a braided tubular body and is thus wound on a reel 18 after having been brought under tension by a new guide system 19.

p0060The braiding machine 17 used is shown a bit more detail in Figure 8. As braiding machine of this kind, one can use such a machine model DBH or DB on the market by the firm Spiraltex, Meximieux, La France. The time of such a machine (of which only a few have been shown) are divided into two groups, 20 time zones with a rotating group in the opposite direction of the spindles 21 of the other group around the axis the braid. The carrying cable 14, not shown here, passes vertically through the middle of the braid.

p0061According to the invention, and unlike the prior art concerning the manufacture of self-expanding guardians, multiple son 22 are unwound from each or some of the time. In fact, prior to braiding, several were envidés son simultaneously on at least a portion of time, preferably over all. As already said, these multiple son from the time are almost joined over their entire length and that is why it was impossible to represent in Figure 8 other than in the form of a wire.

p0062The choice of the number of time depends on the diameter of the desired braid 23.

p0063Advantageously, the braided tubular body has at the end of braiding a diameter slightly greater than the diameter (e.g. D or D₃) Finished guardian, the resting state.

p0064May then remove the braided tubular body its bearer cable.

p0065In a common way, it is then threading the plaited tubular body around a mandrel (e.g. 24 in Figure 2 or Figure 9) having the desired shape suitable. In Figure 2, the mandrel thus has the shape of a cylinder of diameter D for example, having a truncated cone at one end. The braided tubular body is then subjected to axial tension, at its ends. It is, for example, as in Figure 9, tied at 26 at one end and then the other, which subjected to voltage. Then the tubular body follows the external shape of the mandrel 24. It is then subjected to a hardening heat treatment which sets the tubular body the dimensions of the mandrel. After this treatment, in the resting state, the tubular body has the shape illustrated in Figure 2 or 4 respectively in FIG.

p0066According to the invention there is also provided alternatively to extend the braided tubular body and inserted into a tube 25, shown in phantom in Figure 3 or Figure 6, which presents an inner diameter equal to the desired diameter finished guardian. It is then subjected to hardening heat treatment. For example one can imagine that a tubular braid 35 mm in diameter is introduced into a tube of 28 mm internal diameter. The yarn undergoes curing at 550 ° C for 3 hours under an inert atmosphere (argon or nitrogen with 5% hydrogen) or a vacuum of 10-5 torr.

p0067Following this treatment, if the tress was completely inserted into the tube 25 illustrated in Figure 3, the finished stent has a cylindrical shape as in the embodiment according to Figure 1. If, as against one or both ends of the braid project beyond the tube 25 according to Figure 3, they will automatically take the shape of a truncated hyperboloid as shown in FIG 3.

p0068The great advantage of this curing process tube is the finished guardians get an angle between multiple son and a generator which is under the same processing conditions, always identical and perfectly reproducible.

p0069The advantages of the invention will now be illustrated with non-limiting comparative examples. The method of measurement in these examples is to assess the resistance to radial compression tutors. A loop of a wire of 0.12 mm diameter wire, attached at one end to a carrier, is passed around the tutor to be examined, approximately in the middle thereof. Different weights are then suspended at the other end of the wire and the throttle level is then measured diameter obtained for each weight suspended from the measuring wire.

example 1

p0070Comparison between two tutors who are trained to the same number of son (son 40 single and 40 double son respectively) and have approximately the same angle between the son and a generator and the same diameter in the resting state. The son of the tutors are the same and have been woven in the same conditions.

p0071The guardian of the prior art present in the resting state a diameter of 32.77 mm and a 52 ° angle.

p0072The guardian of the invention has the resting state a diameter of 31.4 mm and an angle of 51 °.

p0073Reduced diameter (mm) of the tutor according to the mass suspended measuring wire. <tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="center">Weight (gr)</entry><entry namest="col2" nameend="col2" align="center">Double wire</entry><entry namest="col3" nameend="col3" align="center">single wire</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">0</entry><entry namest="col2" nameend="col2" align="center">31.40</entry><entry namest="col3" nameend="col3" align="center">32.77</entry></row><row><entry namest="col1" nameend="col1" align="center">5</entry><entry namest="col2" nameend="col2" align="center">31,03</entry><entry namest="col3" nameend="col3" align="center">31.34</entry></row><row><entry namest="col1" nameend="col1" align="center">10</entry><entry namest="col2" nameend="col2" align="center">30.77</entry><entry namest="col3" nameend="col3" align="center">30.56</entry></row><row><entry namest="col1" nameend="col1" align="center">20</entry><entry namest="col2" nameend="col2" align="center">30.56</entry><entry namest="col3" nameend="col3" align="center">29,19</entry></row><row><entry namest="col1" nameend="col1" align="center">thirty</entry><entry namest="col2" nameend="col2" align="center">27.94</entry><entry namest="col3" nameend="col3" align="center">27.61</entry></row><row><entry namest="col1" nameend="col1" align="center">50</entry><entry namest="col2" nameend="col2" align="center">26,10</entry><entry namest="col3" nameend="col3" align="center">22.87</entry></row><row><entry namest="col1" nameend="col1" align="center">100</entry><entry namest="col2" nameend="col2" align="center">20,90</entry><entry namest="col3" nameend="col3" align="center">12.68</entry></row><row><entry namest="col1" nameend="col1" align="center">150</entry><entry namest="col2" nameend="col2" align="center">15,39</entry><entry namest="col3" nameend="col3" align="center">8.23</entry></row><row><entry namest="col1" nameend="col1" align="center">180</entry><entry namest="col2" nameend="col2" align="center">11.99</entry><entry namest="col3" nameend="col3" align="center">3.38</entry></row><row><entry namest="col1" nameend="col1" align="center">200</entry><entry namest="col2" nameend="col2" align="center">7.99</entry><entry namest="col3" nameend="col3" align="center">3.13</entry></row></tbody></tgroup></table></tables>

p0074It is clear from these measurement results that from 50g, that is to say, corresponding to physiological conditions in the arteries, significantly more favorable resistances are obtained from the son double tutor.

example 2

p0075Comparison of three tutors who are trained to the same number of son (son 40 single and 40 double son respectively) and have approximately the same diameter in the resting state. The angle of the son with respect to a generatrix of 66 ° to the guardian according to the prior art, it is 49 ° for a guardian X according to the invention and for a 44 ° Y guardian following the invention.

p0076In the resting state, the three guardians have examined the same length, that is to say, about 10 cm. then introduced the guardian of the prior art and the Y tutor in Balt introducer of the type ID5 (5 mm internal diameter) with a length of 50 cm. The guardian of the prior art occupies a length of 44 cm, the guardian Y a length of 18 cm.

p0077guardian of the diameter reduction based on the sprung mass to the measuring wire. <tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="4" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="39.37mm" /><colspec colnum="2" colname="col2" colwidth="39.37mm" /><colspec colnum="3" colname="col3" colwidth="39.37mm" /><colspec colnum="4" colname="col4" colwidth="39.37mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col3" align="center"><b>Double wire</b></entry><entry namest="col4" nameend="col4" align="center"><b>single wire</b></entry></row><row><entry namest="col1" nameend="col1" align="center">Weight (gr)</entry><entry namest="col2" nameend="col2" align="center">Tutor X measured diameter (mm)</entry><entry namest="col3" nameend="col3" align="center">Tutor Y measured diameter (mm)</entry><entry namest="col4" nameend="col4" align="center">Measured diameter (mm)</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">0</entry><entry namest="col2" nameend="col2" align="center">27.50</entry><entry namest="col3" nameend="col3" align="center">27.3</entry><entry namest="col4" nameend="col4" align="center">27.50</entry></row><row><entry namest="col1" nameend="col1" align="center">5</entry><entry namest="col2" nameend="col2" align="center">27.22</entry><entry namest="col3" nameend="col3" align="center">26.98</entry><entry namest="col4" nameend="col4" align="center">27,30</entry></row><row><entry namest="col1" nameend="col1" align="center">10</entry><entry namest="col2" nameend="col2" align="center">27,00</entry><entry namest="col3" nameend="col3" align="center">26.59</entry><entry namest="col4" nameend="col4" align="center">27,10</entry></row><row><entry namest="col1" nameend="col1" align="center">20</entry><entry namest="col2" nameend="col2" align="center">25.37</entry><entry namest="col3" nameend="col3" align="center">26,31</entry><entry namest="col4" nameend="col4" align="center">25.33</entry></row><row><entry namest="col1" nameend="col1" align="center">thirty</entry><entry namest="col2" nameend="col2" align="center">24,80</entry><entry namest="col3" nameend="col3" align="center">25,12</entry><entry namest="col4" nameend="col4" align="center">25.04</entry></row><row><entry namest="col1" nameend="col1" align="center">50</entry><entry namest="col2" nameend="col2" align="center">22.58</entry><entry namest="col3" nameend="col3" align="center">23.46</entry><entry namest="col4" nameend="col4" align="center">23.50</entry></row><row><entry namest="col1" nameend="col1" align="center">100</entry><entry namest="col2" nameend="col2" align="center">16.76</entry><entry namest="col3" nameend="col3" align="center">15.74</entry><entry namest="col4" nameend="col4" align="center">16,20</entry></row><row><entry namest="col1" nameend="col1" align="center">150</entry><entry namest="col2" nameend="col2" align="center">12.92</entry><entry namest="col3" nameend="col3" align="center">12.75</entry><entry namest="col4" nameend="col4" align="center">11,73</entry></row><row><entry namest="col1" nameend="col1" align="center">180</entry><entry namest="col2" nameend="col2" align="center">9.40</entry><entry namest="col3" nameend="col3" align="center">8.36</entry><entry namest="col4" nameend="col4" align="center">9.02</entry></row><row><entry namest="col1" nameend="col1" align="center">200</entry><entry namest="col2" nameend="col2" align="center">7.16</entry><entry namest="col3" nameend="col3" align="center">6.19</entry><entry namest="col4" nameend="col4" align="center">5.60</entry></row></tbody></tgroup></table></tables>

p0078It is clear from this example that a double son guardian with a braiding angle significantly lower than that used in some prior art tutors offer resistance to compression equivalent without the release of previously reported problems.

example 3

p0079Comparison of three tutors who are trained, one (stent C) of 72 individually wrapped son as in the prior art, and the other two 36 double son of the invention.

p0080AC guardians have a diameter to 32 mm idle state. The son guardians A and B have an angle relative to a generator of 53.75 ° and 53.25 °, those guardian C a 55 ° angle.<tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="7" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="22.50mm" /><colspec colnum="2" colname="col2" colwidth="22.50mm" /><colspec colnum="3" colname="col3" colwidth="22.50mm" /><colspec colnum="4" colname="col4" colwidth="22.50mm" /><colspec colnum="5" colname="col5" colwidth="22.50mm" /><colspec colnum="6" colname="col6" colwidth="22.50mm" /><colspec colnum="7" colname="col7" colwidth="22.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" rowsep="0" align="center">Weight (gr)</entry><entry namest="col2" nameend="col7" align="center"><b>measured reduced diameter (mm)</b></entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">AT</entry><entry namest="col3" nameend="col3" align="center">% (AT)</entry><entry namest="col4" nameend="col4" align="center">B</entry><entry namest="col5" nameend="col5" align="center">% (B)</entry><entry namest="col6" nameend="col6" align="center">C</entry><entry namest="col7" nameend="col7" align="center">% (C)</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="center">0</entry><entry namest="col2" nameend="col2" align="char" char=",">32.86</entry><entry namest="col3" nameend="col3" align="center">0,000</entry><entry namest="col4" nameend="col4" align="char" char=",">33.49</entry><entry namest="col5" nameend="col5" align="center">0,000</entry><entry namest="col6" nameend="col6" align="char" char=",">32.99</entry><entry namest="col7" nameend="col7" align="center">0,000</entry></row><row><entry namest="col1" nameend="col1" align="center">10</entry><entry namest="col2" nameend="col2" align="char" char=",">32,10</entry><entry namest="col3" nameend="col3" align="center">2,307</entry><entry namest="col4" nameend="col4" align="char" char=",">32.23</entry><entry namest="col5" nameend="col5" align="center">3,762</entry><entry namest="col6" nameend="col6" align="char" char=",">32.41</entry><entry namest="col7" nameend="col7" align="center">1,752</entry></row><row><entry namest="col1" nameend="col1" align="center">20</entry><entry namest="col2" nameend="col2" align="char" char=",">31.14</entry><entry namest="col3" nameend="col3" align="center">5,229</entry><entry namest="col4" nameend="col4" align="char" char=",">31.43</entry><entry namest="col5" nameend="col5" align="center">6.151</entry><entry namest="col6" nameend="col6" align="char" char=",">31.25</entry><entry namest="col7" nameend="col7" align="center">5,269</entry></row><row><entry namest="col1" nameend="col1" align="center">thirty</entry><entry namest="col2" nameend="col2" align="char" char=",">29.76</entry><entry namest="col3" nameend="col3" align="center">9,428</entry><entry namest="col4" nameend="col4" align="char" char=",">30.93</entry><entry namest="col5" nameend="col5" align="center">7.644</entry><entry namest="col6" nameend="col6" align="char" char=",">30.47</entry><entry namest="col7" nameend="col7" align="center">7.633</entry></row><row><entry namest="col1" nameend="col1" align="center">50</entry><entry namest="col2" nameend="col2" align="char" char=",">27,56</entry><entry namest="col3" nameend="col3" align="center">16.124</entry><entry namest="col4" nameend="col4" align="char" char=",">28.91</entry><entry namest="col5" nameend="col5" align="center">13.676</entry><entry namest="col6" nameend="col6" align="char" char=",">29.24</entry><entry namest="col7" nameend="col7" align="center">11,362</entry></row><row><entry namest="col1" nameend="col1" align="center">70</entry><entry namest="col2" nameend="col2" align="char" char=",">26,12</entry><entry namest="col3" nameend="col3" align="center">20.506</entry><entry namest="col4" nameend="col4" align="char" char=",">26.65</entry><entry namest="col5" nameend="col5" align="center">20.424</entry><entry namest="col6" nameend="col6" align="char" char=",">27.17</entry><entry namest="col7" nameend="col7" align="center">17.637</entry></row><row><entry namest="col1" nameend="col1" align="center">100</entry><entry namest="col2" nameend="col2" align="char" char=",">23.54</entry><entry namest="col3" nameend="col3" align="center">28.358</entry><entry namest="col4" nameend="col4" align="char" char=",">24.63</entry><entry namest="col5" nameend="col5" align="center">26.456</entry><entry namest="col6" nameend="col6" align="char" char=",">23.98</entry><entry namest="col7" nameend="col7" align="center">27.307</entry></row><row><entry namest="col1" nameend="col1" align="center">130</entry><entry namest="col2" nameend="col2" align="char" char=",">20.27</entry><entry namest="col3" nameend="col3" align="center">38.310</entry><entry namest="col4" nameend="col4" align="char" char=",">21,29</entry><entry namest="col5" nameend="col5" align="center">36.429</entry><entry namest="col6" nameend="col6" align="char" char=",">20,05</entry><entry namest="col7" nameend="col7" align="center">39.220</entry></row><row><entry namest="col1" nameend="col1" align="center">150</entry><entry namest="col2" nameend="col2" align="char" char=",">17,58</entry><entry namest="col3" nameend="col3" align="center">46.497</entry><entry namest="col4" nameend="col4" align="char" char=",">19.61</entry><entry namest="col5" nameend="col5" align="center">41.445</entry><entry namest="col6" nameend="col6" align="char" char=",">19.43</entry><entry namest="col7" nameend="col7" align="center">41,100</entry></row><row><entry namest="col1" nameend="col1" align="center">170</entry><entry namest="col2" nameend="col2" align="char" char=",">17,02</entry><entry namest="col3" nameend="col3" align="center">48.201</entry><entry namest="col4" nameend="col4" align="char" char=",">18,45</entry><entry namest="col5" nameend="col5" align="center">44.909</entry><entry namest="col6" nameend="col6" align="char" char=",">16.37</entry><entry namest="col7" nameend="col7" align="center">50.376</entry></row><row><entry namest="col1" nameend="col1" align="center">200</entry><entry namest="col2" nameend="col2" align="char" char=",">16.18</entry><entry namest="col3" nameend="col3" align="center">50.758</entry><entry namest="col4" nameend="col4" align="char" char=",">16.77</entry><entry namest="col5" nameend="col5" align="center">49.925</entry><entry namest="col6" nameend="col6" align="char" char=",">12.59</entry><entry namest="col7" nameend="col7" align="center">61.835</entry></row></tbody></tgroup></table></tables>

p0081It is clear from this example that gets a compression resistance equivalent, if not better, guardians of the invention compared to the tutor made in the prior art. It should be noted that, to make the guardian C, it was necessary to use an apparatus comprising a braiding machine 72 spindles, which is exceptional (and expensive) and is much more complex to handle. Such a machine is also cumbersome, and much noisier.

p0082Rather guardians A and B can be manufactured on the same braiding machines as those used so far (eg to 36 zones).

p0083It should be understood that the present invention is in no way limited to the forms and embodiments described above and that many modifications can be made thereto without departing from the scope of the appended claims.