CN101247772A

CN101247772A - Artificial graft tubing

Info

Publication number: CN101247772A
Application number: CNA2006800226923A
Authority: CN
Inventors: 科林·杰拉尔德·卡罗
Original assignee: Veryan Medical Ltd
Current assignee: Veryan Medical Ltd
Priority date: 2005-06-24
Filing date: 2006-06-26
Publication date: 2008-08-20
Also published as: GB2427668A; GB0512936D0

Abstract

A method of making artificial graft tubing is disclosed. The method comprises providing a helical mandrel having a centre line following a substantially helical path, providing a generally tubular wall having a longitudinally extending cavity, positioning the helical mandrel inside the tubular wall so that the longitudinally extending cavity has a centre line following a substantially helical path, and causing the tubular wall to retain, at least partly, the shape with the longitudinally extending helical cavity. Another method comprises providing a mandrel having a substantially helical groove, providing a generally tubular wall having a longitudinally extending cavity, positioning the tubular wall at least partly in the groove so that the longitudinally extending cavity has a centre line following a substantially helical path, and causing the tubular wall to retain, at least partly, the shape with the longitudinally extending helical cavity.

Description

Artificial graft tubing

The present invention relates to make the method for artificial graft tubing and the graft tubing of making by this method.

We once propose in the past, and the flow pattern in the tremulous pulse that comprises the vortex type that is caused by its non-planar geometry plays inhibitory action to the development such as the angiopathy of thrombosis, atherosclerosis and neointimal hyperplasia etc.

Recognize that from WO 95/09585 it provides a kind of artificial blood vessel, this artificial blood vessel is included in the section that is generally hollow conduit that two ends have opening, and comprises that nonplanar sweep flows through this sweep to impel the eddy-currents in the blood.As explained in that publication, the eddy-currents that is caused by the deflection of blood flow in described nonplanar sweep has improved flow behavior, and has reduced the probability that forms precipitate and comprise the angiopathy of neointimal hyperplasia.

People such as Caro have explained among the 2P at (1998) J.Physiol.513P how the conduit of non-planar geometry suppresses flow instability.How useful others obtain explaining in J.R.Soc.Interface (2005) 2,261-266 eddy-currents.

From WO 2004/082534, recognize and to make synthetical helical graft by the pipe that twines flexible material around axle, so that this pipe has such shape, be that its longitudinal extension chamber has helical centre, and then pipe carried out heat cure, thereby make it keep helical form at least in part.In a kind of method shown in Figure 12 A to Figure 12 E, axle is formed by being configured as spiral helicine rigid rod.In the other method shown in Figure 13 A and Figure 13 B, axle is made up of straight steel pole, twines and be fixed with steel wire thereon in a spiral manner.In both cases, because graft material is soft and pliable and tough, so in the process of twining, must support flexible pipe so that it keeps its section shape in this process around axle.The supporting of being made up of silicone rubber tube of a kind of flexible graft tubing inside is suggested.Therefore, this method also needs extra assembly except the axle that needs the flexible pipe outside.In addition, must careful operation have shape accurately, and then make screw pitch (pitch) and amplitude that final graft has to be needed to guarantee flexible pipe.The initial winding that flexible pipe is wound on the axle must be carried out exactly, and in curing process, need then it is remained on position accurately along its length.

According to a first aspect of the invention, provide a kind of method of making artificial graft tubing, comprised screw mandrel is provided, it has along the centrage in the path of basic spiral; Common tubular wall is provided, and it has the longitudinal extension chamber; Screw mandrel is placed on tubular wall inside, so that the longitudinal extension chamber has along the centrage in the path of basic spiral; And make tubular wall keep the shape of longitudinal extension helical cavity at least in part.

The benefit of this axle is suitably to limit that tubular wall will adopt will be required spiral-shaped, for example aspect helical angle and amplitude.Tubular wall will be formed the shape that conforms to the reservation shape of axle effectively automatically.

This axle can also keep the section shape in required longitudinal extension chamber.This can be by axle closely cooperating and guarantee in tubular wall, and for example the diameter of axle is at least 90% cooperation of the internal diameter of tubular wall, and more preferably 95%.

Usually, by being placed on, tubular wall make its shape be modified to helical form on the axle from basic original shapes (preferred basic) for cylindrical.Thereby the shape of the tubular wall that is pre-existing in is revised by being placed on inner axle.Should " inner " axle can be by for example stainless rapid prototyping laser sintered or make by for example stainless cylindrical bar is ground.

The graft tubing of making by method disclosed herein is suitable for using in vivo, in the body of the mankind or animal.This graft tubing is suitable for use as and delivers for example prosthese of the body fluid of blood.For example this conduit can be used as artificial blood vessel.For example for dialysis, this conduit can be used as broken so that blood is extracted and fails back the vascular access graft of type with acupuncture.Therefore this conduit can directly deliver the body fluid that contacts with pipe inner wall.

Alternatively, conduit can be placed on the outside of the natural conduit of human body or animal body, blood vessel for example complete or that transplant.Thereby conduit can be used as external jacket or support to the natural conduit of carrier liquid stream.When using graft tubing, in inserting process, will need sometimes graft tubing is longitudinally cut so that insert the nature conduit in the outside of natural conduit.If doctor's indication, this incision can be by repairings such as stitchings so.

Preferably, tubular wall is carried out heat cure to keep the shape in longitudinal extension chamber at least in part.Because used internal mandrel, so tubular wall can be exposed to the external heated environment equably in curing process.

In a preferred embodiment, tubular wall is made by ePTFE.At this moment, adopting heat cure keeping under the spiral-shaped situation, tubular wall can be heated to 340 to 380 ℃ temperature range, it more preferably is 350 to 370 ℃, time range is 10 to 30 minutes, more preferably is 15 to 25 minutes, thereby the tubular wall thermosetting is turned to helical form.In most preferred method tubular wall be heated to 360 ℃ 20 minutes.

Knownly provide columned PTFE graft, it is subjected to external support by twining polymer filaments spirally.The purpose of this supporting for example is when crossing the node implantation graft, reduces the probability of kink.The helical angle of the graft filament of this external support (being the angle of the graft longitudinal axis) is about 80 ° or bigger.We find that the graft of this class is the suitable raw material that is used to realize the inventive method.Therefore, preferably, tubular wall comprises the supporting that spiral twines.Preferably this supporting is arranged on the outside of tubular wall.The helical angle of the supporting of being twined by spiral preferably is at least 70 °.The supporting that spiral twines can be the form of band or overcoat.

In some preferable methods, when tubular wall is supported by axle, extended part is applied on the tubular wall to extend axially on tubular wall.This extended part is configured to help reduce any probability that the reduction of helical amplitude was stretched also thereby caused to helical graft.If near the extending axially or the two combination that is used in the joint in response to arterial pressure or graft for example is because by fluidic internal pressurization, this probability of stretching can occur.The further reason of stretching can be in inserting process, when graft may be elongated.

In the manufacture method of in WO 2004/082534, describing, be in when cylindrical at pipe, its be deformed turn to helical form with thermosetting before, will be used for this spiral footing of stretching of impedance and be applied to pipe.Yet it is initial when cylindrical when conduit is in, and may be difficult to this spiral footing accurately is applied on the conduit, especially when pipe is material manufacture by relative flexibility.Described similar method in WO 2004/082520, it is used for the conduit of the body fluid flow pipe of outside alternative such as blood vessel about production.

Yet in comprising the embodiments of the present invention of using the elongation reinforcement feature, because tubular wall is internally supported by axle, institute is so that be applied to extended part on the axle.Internal mandrel allows extended part that tubular wall is exerted pressure and can not cause the tubular wall distortion.

Extended part can be forms such as band, pearl, line, filament.The width of extended part (being the size of extended part at the circumferencial direction of tubular wall) can be wide or narrow.One or more extended parts can be set.A plurality of extended parts can be used for providing the ductile additional resistance to graft tubing.

Extended part can be applied to basically and only longitudinally extend with respect to tubular wall.This will mean that this extended part can be effectively only in tubular wall " side ".If be positioned at the outside of tubular wall, as seen and not extended part will all can disappear in the back of tubular wall along this side.

Preferably, extended part has annulus and longitudinal component.Therefore, one preferred embodiment in, extended part is applied to respect to tubular wall and circumferentially and longitudinally extends.Thereby extended part will have himself helical angle and corresponding pitch.Because helical angle is big more, the axially extended impedance to graft tubing that is provided by extended part is tending towards reducing more, therefore needs the helical angle of extended part not too big usually.When measuring, helical angle is preferably less than 70 ° to (promptly rotating the axle that is centered on respect to the helical centre in longitudinal extension chamber) when the integral shaft with respect to tubular wall.For example, helical angle can be between about 30 ° and 40 °.

Preferably, extended part is applied to along the tubular wall spiral extension, more than or equal to the pitch (being the helical angle that helical angle is less than or equal to helical centre) of the helical centre in longitudinal extension chamber, more preferably its pitch equals the pitch of helical centre to its pitch substantially approximately.

Extended part can be applied on the tubular wall in many ways, for example sew up by using suitable adhesive or passing through.Extended part can be attached on the tubular wall off and on, if attachment point or zone at quantity and density epipodium so that extended part helps tubular wall to keep helical form.Preferably, extended part is attached on the tubular wall continuously along its length.Most preferably be for example extended part to be attached on the tubular wall by heating steps.This can comprise heat-activatable adhesive, or use forms tubular wall and/or extended part in heating to form the material that softens in the bonded process or melt.

In a preferred method, an end of extended part can be fixed on axle or the tubular wall, and when being applied on the tubular wall spirally, can make it bear longitudinal tension force then, to guarantee the degree of contact pressure between extended part and the tubular wall.

Can after initial thermal cure step, apply extended part, can extended part be attached on the tubular wall by further heating or adhesion step.Yet, preferably, can adopt the single heating steps to carry out heat cure so that it keeps the shape in longitudinal extension chamber at least in part extended part is attached on the tubular wall and simultaneously to tubular wall.Thereby inextensible relatively graft tubing can be made by the single heating steps.

A kind of preferable methods comprises by the inside that screw mandrel is placed on tubular wall is shaped tubular wall, thereby makes tubular wall have helical form; When tubular wall is supported by screw mandrel, extended part is applied on the tubular wall, thereby extended part is longitudinally extended about tubular wall; And screw mandrel, tubular wall and extended part heated with the heat cure that causes tubular wall and extended part is attached on the tubular wall.

One preferred embodiment in, tubular wall and extended part are made by ePTFE.For example they can be heated to 0 to 350 ℃ temperature 10 to 15 minutes, so that its thermosetting is turned to helical form, and extended part be attached on the tubular wall.Preferred value is 340 ℃ and 10 minutes.

After the shape of tubular wall has been modified to helical form, on tubular wall, use extended part and be considered to have independently patentable significance.Therefore, according to a second aspect of the invention, provide a kind of method of making artificial graft tubing, described method comprises: the common tubular wall with longitudinal extension chamber is provided; Described tubular wall is shaped so that the longitudinal extension chamber has along the centrage in the path of basic spiral; Make described tubular wall keep the shape of described longitudinal extension helical cavity at least in part; And thereafter described tubular wall is used extended part so that extended part longitudinal extension on described tubular wall.

In case after tubular wall is in spiral status extended part is applied on the tubular wall, tubular wall can be accepted the application of extended part better.

Because extended part is for the tubular wall longitudinal extension, it is tending towards reducing the axially-extending of graft tubing.If the length of graft tubing is reduced, the minimizing of amplitude of helical centre in longitudinal extension chamber and the increase of corresponding screw pitch will be made.By providing extended part to reduce this effect of stretching.

Make tubular wall keep spiral helicine step to comprise at least in part tubular wall is carried out heat cure.Therefore, a kind of preferable methods comprises: first heating steps, and wherein tubular wall is turned to helical form by thermosetting; And second heating steps, after being applied to extended part on the tubular wall, carrying out, extended part is incorporated on the tubular wall in second heating steps.The heating-up temperature of tubular wall is preferably lower than the heating-up temperature of tubular wall in second heating steps in first heating steps.

Shaping that can be by the accomplished in many ways tubular wall is used inner axle so that the longitudinal extension chamber of tubular wall has helical centre and needn't be limited to.In a kind of preferable methods, tubular wall is by being entwined shape around axle.This axle is in " outside " of tubular wall.The material of making tubular wall may be quite soft and pliable and tough, if thereby with it around for example columniform axle winding and keep the section shape of himself simultaneously, then will encounter difficulties.Therefore, axle preferably has the groove of admitting the basic spiral of tubular wall to small part.Be configured as in the spiral helicine process at first and making tubular wall keep at least in part in the process of spiral helicine step at tubular wall, this groove part can be used as the supporting of tubular wall.It can further provide supporting in the process that extended part is applied on the tubular wall, if tubular wall remains on the axle in this step.

Preferably helical groove is set to provide some supporting to the opposite side of tubular wall.It preferably is shaped as corresponding with the outer surface part of contact groove in the tubular wall.This can help to reduce by axle as far as possible stays cutter trade on the tubular wall.Section at tubular wall is configured as under the circular situation, and groove can have the section shape of part circular.Groove can have a pair of sidewall that is separated by diapire.In the latter case, tubular wall can engage so that suitably supported with the first side wall, diapire and second sidewall.Sidewall and diapire can be bending or straight.

By twining around axle in the method that makes the tubular wall shaping, can use interior support keep its section shape in the inside of tubular wall above-mentioned to help tubular wall.Yet, preferably do not use interior support.

Before using extended part, spiral helicine tubular wall can be removed from axle.Yet, preferably when tubular wall is supported by axle, extended part is applied on the tubular wall.This can help for example correctly to use extended part according to required helical angle.If for example tubular wall is by being entwined shape around axle, can under the winding state of tubular wall, contact by making the radial most external of extended part and tubular wall, and extended part is applied on the tubular wall with the helical angle identical with tubular wall so.Screw mandrel is being inserted under the situation of tubulose pars intramuralis, the part that axle is used extended part to tubular wall provides supporting.Therefore, this layout is convenient to use the extended part of common longitudinal extension, and perhaps its helical angle is different from the extended part of the helical angle of tubular wall.

Preferably, extended part is applied in the outside of tubular wall.Therefore, extended part is to the minimum that influences of the section shape in longitudinal extension chamber.When graft is used and directly or when the external jacket of natural blood vessel being delivered body fluid mobile, because may cause comprising the flow disturbance of fluid stagnation in the zone of fin or groove, so need avoid the fin or the groove of any inside.By extended part being applied to the outside of tubular wall, if especially when using extended part on the tubular wall radially inner pressure be minimized, so any inside that is caused by extended part is protruded and can both be avoided substantially.

Various other features about the graft tubing manufacturing described herein can be in conjunction with a second aspect of the present invention, use individually or with any combination.

The axle that use has basic helical groove is considered to have patentable significance to make artificial graft tubing.Therefore, according to a third aspect of the invention we, the invention provides a kind of method of making artificial graft tubing, described method comprises: the axle that the groove with basic spiral is provided; The common tubular wall with longitudinal extension chamber is provided; Described tubular wall is placed in the described groove so that described longitudinal extension chamber at least in part to have along the centrage in the path of basic spiral; And make described tubular wall keep the shape of described longitudinal extension helical cavity at least in part.

As mentioned above, tubular wall is placed at least in part in the groove process and when making it keep helical form at least in part, this helical groove can provide the supporting to tubular wall.Usually, tubular wall will be placed in the helical groove at least in part generally.Thereby in preferred embodiment, the centrage of longitudinal extension helical cavity extends along groove at least.This axle can be with extended part or is not therewith used to help impedance and extend axially.

Various other features about the graft tubing manufacturing described herein can be in conjunction with a third aspect of the present invention, use individually or with any combination.

Aspect all, tubular part can be made by various biocompatible materialses of the present invention.Can use woven or non-woven fabric, preferably make by macromolecular material.A kind of suitable material is expanded PTFE (ePTFE), and it can use separately or combine with other polymer or additive.Another kind of suitable biocompatible materials is a polyester, for instance, as is called as the knitted polyester yarn of the polyethylene terephthalate of Dacron (trade mark).

Extended part (if providing) also can be made by various for example above-mentioned biocompatible materialses.A kind of suitable material that is used for extended part can be polypropylene.

The type of tubular wall can be carried out externally reinforced for twined (with very large near 90 ° of helical angles) stiffener by a plurality of circular stiffeners or spiral.A kind of stiffener of form can be band, band, outer housing etc., thus its vascular access graft that will laterally pierce through repeatedly by pin when being suitable for being made into to use.The stiffener of another kind of form is a pearl etc., and it is radially outward outstanding from tubular wall, and has longitudinal separation usually between adjacent pearl ring or coil.This conduit is used in the prosthese that is subjected to outer bend power, for example passes the joint as knee, and pearl helps to keep circular section.In some cases, pearl etc. uses with band, band, outer housing etc.

Having tubular wall that circle or spiral twine stiffener,---for example to use the method for the shape of internal mandrel---for method described herein be suitable starting point.In the embodiment that the present invention includes this stiffener that extended part additionally is provided, except the stiffener of circle or spiral, also used extended part.Have big relatively helical angle (as 70 the degree or more than) stiffener the character that is for example fitly pierced through or resist transverse compression or kink can be provided.Extended part with relatively little helical angle (for example less than 40 degree) can be resisted extending axially of graft tubing and therefore resist the tendency of any minimizing helical amplitude.

In description, helical amplitude refers to the degree of the displacement from the mean place to the lateral extreme, therefore, has at tubular wall under the situation in the longitudinal extension chamber of containing helical centre, and amplitude is half of whole transverse widths of helical centre.

Graft tubing can be manufactured to along its length has essentially identical amplitude and helical angle.When using graft tubing, may have little variation, this variation is that the elongation of the graft tubing that caused by tensile load or contraction cause or is caused by torque load.Yet, may exist to make graft tubing have the helical angle of variation and/or the situation of amplitude, in order to adapt to spatial restriction or to optimize flox condition.This can realize by suitable customization axle (no matter being outside or internal type).

For the simplification of making, preferably graft tubing is fabricated to and has chamber longitudinally, this chamber has the substantially invariable hatch region along its length.In addition, may have the variation that causes by the load on the graft tubing during use.The section shape of graft tubing lumen is preferably produced and is circle.

The helix wall can only form the part of the whole length of graft tubing, or extends on its whole length substantially.

The helix wall can experience an entire volume around a part, for example reel 1/4th, half or 3/4ths.Preferably, graft tubing partly experiences at least one coiling.More preferably, a plurality of at least coilings.Spiral will help to guarantee to produce and keep vortex flow along the coiling repeatedly of tubular wall.

The present invention also extends to the graft tubing of being made by method described herein, and this graft tubing is in human body or the intravital use of animal.

Can in multiple biomedicine, use by the graft tubing that the method for this paper announcement is made, for example in various tremulous pulsies (as at femur, coronary artery and renal artery), vein and non-cardiovascular, use, as in gastrointestinal tract (as bile or pancreatic duct), urogenital (as ureter or urethra) or respiratory system (pulmonary respiration road).Thereby the present invention extends to the manufacturing of the graft tubing that is used for the body fluid except blood, and it is used for directly delivering fluid or is used for (intact or transplant) fluid conduit systems around nature.

Mode that below will be by example also describes some of the preferred embodiment of the invention with reference to the accompanying drawings, wherein:

Fig. 1 shows the axle in tubular wall inside to be placed;

Fig. 2 shows the tubular wall of the axle of having inserted Fig. 1 therein;

Fig. 3 shows by the axle supporting, also application thereon has the tubular wall of extended part;

Graft after Fig. 4 shows axle with Fig. 1 and removes;

Fig. 5 shows another graft of making the axle that Fig. 1 is arranged;

Fig. 6 shows the axle for the treatment of to twine around it tubular wall;

Fig. 7 shows the axle of tubular wall Fig. 6 in position;

Fig. 8 shows axle and the tubular wall of Fig. 7 and is applied to extended part on the tubular wall; And

Fig. 9 shows the graft after the axle with Fig. 6 removes.

Fig. 1 shows a kind of instrument with form of axle 10. Axle be have spiral helicine Stainless steel. In this embodiment, this axle by the rose cutter in the CNC milling machine by circle The cylindrical stainless steel bar is made. Draft coordinate so that required spiral to be provided at CAD/CAM system Pitch and amplitude. Be the inside that is inserted into tubular wall 6 with central spindle design, in order to revise the vertical of pipe To the chamber so that it meets the shape of this screw mandrel. This point can be found out in Fig. 2.

Fig. 3 shows the stage after a while, and this moment, form was that the extended part of band 8 is employed To pipe 6, thus with pipe 6 identical helical angles and pitch along pipe 6 longitudinal extensions.

Graft after Fig. 4 shows axle with Fig. 1 and removes.

Another graft after Fig. 5 shows axle with Fig. 1 and removes. Outside this graft has Section's spiral supporting band 20.

Fig. 6 shows the instrument that a kind of form is axle 2, and axle 2 is formed with along its length The helical groove 4 that extends. In this concrete embodiment, axle is passed through in the CNC milling machine Ball nose gouge bit milling cutter is made by cylindrical stainless steel. Draft seat at CAD/CAM system Be marked with the screw pitch and the amplitude that provide required. Amplitude is determined by cutting depth.

As shown in Figure 7, the diameter of groove is suitable for admitting tubular wall or manages 6. In this case, This pipe is traditionally as the type of graft, and its form is the cylindrical of standard and by ePTFE Make. The common rectilinear form of this Guan Congqi is configured as along the helical groove 4 of axle 2 then Shape.

In Fig. 8, the extended part of band 8 forms is applied on the pipe 6. Band 8 along Pipe is longitudinal extension in spiral, and described spiral has with helical groove and (and is shaped by groove Pipe) identical pitch.

Fig. 9 shows graft 12, and it is by spiral tubular wall and externally be attached to this pipe Band 8 on the shape wall forms. This graft has its center line along the spiral path longitudinal extension Chamber 14. Rely on the band 8 of longitudinal extension, no matter in the process of for example being inserted by the surgeon Or in the surgical procedure in human body or animal body, graft all tends to opposing and extends axially.

Embodiment 1

Used traditional columniform pipe of making by ePTFE, can be used as artificial blood vessel.The internal diameter of this pipe is about 6mm and external diameter is about 7mm.The axle of Fig. 1 is inserted in this pipe.The external diameter of axle is about 5.8mm.The internal diameter of this pipe is about 6mm to guarantee that it is closely cooperated with axle.As shown in Figure 2, initial cylindrical tube is deformed into helical form.To be flattened to zonal ePTFE filament twines around the pipe on the axle then, the pitch that band twines is identical with the pitch of axle.Be fixed on the axle end of band and the longitudinal stretching band.Because band is twined around curved surface, so this longitudinal stretching makes this band apply normal force (or pressure), guaranteed band and graft closely and put.

Then black box was placed in 330 ℃ the baking oven 10 minutes.This makes the ePTFE of pipe and band fully soften so that it is bonded to each other.This assembly is cooled off in room temperature.Thereby produce graft as shown in Figure 8.

Found to make band be adhered to securely on the outside of pipe by this process.And the inside of graft can not produce observable ridge or groove.As the result of this process, it is not extensible fully that graft becomes.Yet graft can be bent into to have and be about 1/3 curvature (radius/radius of curvature of pipe), for example U type pipe.

Do not reduce the inextensibility of graft with the broken band that adheres to of acupuncture (contingent when being used to the kidney dialysis patient) when graft.Even on the whole width of band, pierce through repeatedly, also find only have partial effect and graft is made the as a whole inextensibility that still keeps satisfactorily so that it is cut off effectively.

As mentioned above, finished the manufacturing of the graft of the spiral reinforcing in single heating steps.

Embodiment 2

The axle of Fig. 1 is inserted into the pipe as embodiment 1 described same-type.The diameter of pipe is set to make it to guarantee closely to cooperate with axle.As shown in Figure 2, being initially columniform pipe is deformed into and has spiral type.In this example, band is not twined around this pipe.All components was placed in 330 ℃ the baking oven 10 minutes, and made its cooling then.Axle is removed from become spiral helicine pipe.

Embodiment 3

In this example, used the internal diameter made by ePTFE pipe as 6mm.Pipe is cylindrical and is provided with external helicoid support outer housing or is with 20 with what the helical angles that are about 80 degree were twined.In the axle insertion tube with Fig. 1.As shown in Figure 2, initial cylindrical tube is deformed into and has spiral type.Band 8 (as used among the embodiment 1) is not twined around pipe.All components was placed in 360 ℃ the baking oven 20 minutes, and made its cooling then.Axle is removed from become spiral helicine pipe.The helical form graft of making is shown in Figure 5.When graft is applied tensile load, find that graft demonstrates axially extended gratifying resistance.

Embodiment 4

The axle of Fig. 1 is inserted into the pipe as embodiment 1 described same-type.The diameter of pipe is set to make it to guarantee closely to cooperate with axle.As shown in Figure 2, being initially columniform pipe is deformed into and has spiral type.Pipe and axle were placed in 275 ℃ the baking oven one hour, in the air of room temperature, make its cooling then.As the band of making by ePTFE of embodiment 1 described same type, by to be applied on the pipe with the same helical angle of pipe.This goes up to guarantee close contact, fixedly to finish so that keep its position at the two ends of band by anchor clamps then by band is wound into pipe with little tension force.With the combined heated of axle, pipe and band to about 350 to 360 ℃ 30 minutes.This will manage and the ePTFE of band fully softens so that it is bonded to each other.Be produced with graft like the graft type shown in Fig. 9.

Embodiment 5

Used the pipe of making by as embodiment 1 described same type, the pipe of the traditional cylindrical of promptly making, can be used as artificial blood vessel by ePTFE, its internal diameter is about 6mm and external diameter is about 7mm.The helical groove 4 that is about 8mm along width twines pipe around axle as shown in Figure 7.Pipe was placed in 275 ℃ the baking oven one hour, and cooled off with its taking-up and then in the air of room temperature then.This heating steps is a thermal cure step, and the shape of pipe is set to by the definite general spiral type of helical groove thus.

When pipe is still on axle, will be applied on the pipe by the band that ePTFE makes.Thereby band is wound into the distortion minimum that pipe is gone up the section that makes pipe with a spot of tension force, guarantees simultaneously to contact closely with pipe.Band is placed on approx the center of the groove on the radially outmost surface of pipe, so that it has the helical angle identical with pipe.By anchor clamps the two ends of band are fixed so that it is kept in position.Then the combination of axle, pipe and band was placed in about 350 to 360 ℃ baking oven 30 minutes.This is with the ePTFE pipe and band is fully softening and it is bonded to each other.This is combined in to cool off in the air of room temperature removes from axle then.So just, formed the graft shown in Fig. 9.The width of band 8 is about 1.3mm and thickness is about 0.3mm.

In control experiment, the deformability of having found pipe makes and to be difficult to obtain required having the band that homogeneous contact with pipe, is difficult to before managing heat cure band is applied on the pipe when therefore stating the ePTFE pipe in the use.Yet in embodiment 5, process is owing to being after thermal cure step on the surface that band is applied to pipe, and therefore pipe is not yielding, thereby is convenient to place band so that it contacts closely with pipe.This makes that band and pipe have good binding in second heating steps.Found in forming step or used in the step of band need the supporting insertion tube inside.

Claims

1. a method of making artificial graft tubing comprises screw mandrel is provided, and it has along the centrage in the path of basic spiral; Common tubular wall is provided, and it has the longitudinal extension chamber; Described screw mandrel is placed on described tubular wall inside, so that described longitudinal extension chamber has along the centrage in the path of basic spiral; And make described tubular wall keep the shape of described longitudinal extension helical cavity at least in part.

2. the method for claim 1, wherein said tubular wall is initial to be cylindrical substantially.

3. method as claimed in claim 1 or 2, wherein said tubular wall are heat cured so that it keeps the shape in described longitudinal extension chamber to small part.

4. as claim 1,2 or 3 described methods, wherein said tubular wall comprises the supporting that spiral twines.

5. any described method in the claim as described above comprises when described tubular wall during by described axle supporting, extended part is applied on the described tubular wall in case on described tubular wall longitudinal extension.

6. method as claimed in claim 5, wherein said extended part are applied to about described tubular wall extends circumferentially and longitudinally.

7. method as claimed in claim 6 comprises when being applied to described extended part on the described tubular wall, at one end described extended part is fixed and is made it be subjected to stretching longitudinally.

8. as claim 6 or 7 described methods, wherein said extended part is applied to along described tubular wall and extends spirally, and its pitch equates with the pitch of described helical centre substantially.

9. as claim 5,6,7 or 8 described methods, wherein described extended part is attached on the described tubular wall by heating steps.

10. method as claimed in claim 9, wherein said heating steps is independent heating steps, is used for described extended part is attached on the described tubular wall and to described tubular wall carrying out heat cure so that described tubular wall to small part keeps the shape in described longitudinal extension chamber.

11. a method of making artificial graft tubing, described method comprises: the common tubular wall with longitudinal extension chamber is provided; Described tubular wall is shaped so that described longitudinal extension chamber has along the centrage in the path of basic spiral; Make described tubular wall keep the shape of described longitudinal extension helical cavity at least in part; And thereafter described tubular wall is used extended part with longitudinal extension on described tubular wall.

12. being applied to about described tubular wall, method as claimed in claim 11, wherein said extended part extend circumferentially and longitudinally.

Extend spirally 13. method as claimed in claim 12, wherein said extended part are applied to along described tubular wall, its pitch equates with the pitch of described helical centre substantially.

14., wherein make described tubular wall keep spiral helicine step to comprise at least in part described tubular wall carried out heat cure as claim 11,12 or 13 described methods.

15., wherein described extended part is attached on the described tubular wall by heating steps as any described method in the claim 11 to 14.

16. as any described method in the claim 11 to 15, wherein by described tubular wall is twined so that described tubular wall is shaped around axle.

17. method as claimed in claim 16, wherein said axle has the groove of basic spiral, and described tubular wall is contained in the described groove at least in part.

18., wherein be placed on described tubular wall inside described tubular wall be shaped by axle with basic spiral as any described method in the claim 11 to 15.

19., wherein when described tubular wall is supported by described axle, described extended part is applied on the described tubular wall as claim 16,17 or 18 described methods.

20., wherein described extended part is applied to the outside of described tubular wall as any described method in the claim 11 to 19.

21. a method of making artificial graft tubing, described method comprises: the axle that the groove with basic spiral is provided; The common tubular wall with longitudinal extension chamber is provided; Described tubular wall is placed in the described groove so that described longitudinal extension chamber at least in part to have along the centrage in the path of basic spiral; And make described tubular wall keep the shape of described longitudinal extension helical cavity at least in part.