WO2020144208A1

WO2020144208A1 - Scoring catheter

Info

Publication number: WO2020144208A1
Application number: PCT/EP2020/050270
Authority: WO
Inventors: Isabel PÉREZ SERRANOS; Luis Duocastella Codina; Marta Duran Priu; Arnau VIDAL PARREU
Original assignee: Life Vascular Devices Biotech, S.L.
Priority date: 2019-01-09
Filing date: 2020-01-08
Publication date: 2020-07-16

Abstract

A scoring catheter (100) for scoring plaque on a body vessel is provided. The scoring catheter comprises a catheter body (110), an inflatable balloon (120), an expandable scoring structure (140) and a resilient structure (130) to compensate a shortening of the scoring structure upon expansion. The expandable scoring structure is arranged on the balloon and comprises a distal end (141), a proximal end (142), a scoring zone (143) to contact the wall of a vessel, and a distal end zone (144). The resilient structure is arranged on the catheter body and proximal with respect to the expandable scoring structure. The resilient structure has a distal end (131) attached to the proximal end of the scoring structure and a proximal end. The scoring structure comprises longitudinal struts (220,320), the number of longitudinal struts in the scoring zone being higher than in the distal end zone. A method for manufacturing a scoring catheter is also provided.

Description

Scoring catheter

The present disclosure relates to scoring catheters, more specifically to scoring catheters deployed by balloon inflation.

The present application claims the benefit and priority of EP 19 382 012.3, filed on January 09, 2019.

BACKGROUND

Occlusion of body vessels such as arteries due to the accumulation of plaque e.g. fatty plaques, cholesterol, calcium etc., on vessel wall progressively leads to a reduction of blood flow and consequently of oxygen. Such obstruction may cause health problems e.g. ischemia, brain injury and even cause death.

Several methods are known to treat such occlusions. In angioplasty procedures the plaque is pushed against the vessel wall by inflating a catheter balloon. As a result, the plaque is compacted and the internal conduit of the vessel is widened, and so the blood flow is increased. The balloon catheters prepare the vessel for further stent implantation

Alternatively, some procedures use a scoring catheter that puts more effectively the plaque against de vessel thereby clearing the conduit and allowing the blood flow to be restored. Some scoring catheters comprise a metallic wire, i.e. a scoring wire, arranged on an inflatable balloon which, upon expansion, causes the wire to move against the plaque, thus eroding the plaque and preparing it for stent implantation.

Due to the sinuous passages of the circulatory system, delivering scoring catheters to be placed at the zone to be treated may be difficult. In addition, the deployment of the balloon and the subsequent scoring may cause a sudden and undesired release of a significant amount of plaque, which may cause thrombosis. Furthermore, a complex scoring wire structure may lead to failures upon expansion, e.g. strut fracture, which may lead to a poor performance of the scoring catheter.

It may be desirable to at least partly reduce the cited drawbacks, for example by facilitating and improving the delivery of scoring catheters, especially through tortuous anatomy passages, and/or reducing the risk of damage to the vessels. SUMMARY

In a first aspect, a scoring catheter for scoring plaque on a body vessel is provided. The scoring catheter comprises a catheter body; an inflatable balloon arranged on the catheter body; an expandable scoring structure and a resilient structure. The expandable scoring structure is arranged on the balloon and comprises a distal end, a proximal end, a scoring zone to contact the wall of a vessel when expanded, and a distal end zone between the scoring zone and the distal end. The resilient structure is arranged on the catheter body and proximal with respect to the expandable scoring structure, to compensate a shortening of the scoring structure upon the expansion of the scoring zone. The resilient structure has a distal end attached to the proximal end of the scoring structure, and a proximal end. The scoring structure comprises longitudinal struts, wherein the number of longitudinal struts in the scoring zone is higher than the number of longitudinal struts in the distal end zone.

A scoring structure having less longitudinal struts in the distal end zone provides an increased flexibility to the catheter which facilitates guiding the scoring catheter through sinuous body vessels and reduces the risk of damage caused by friction or punctures. Moreover, a reduced diameter as consequence of having less struts in the distal end zone enables the device to be compacted into a highly compressed state having a low profile and to enhance the crossability of the device, i.e. the ability of the scoring catheter to pass through a reduced vessel passageway formed due to the plaque. Having a lower number of longitudinal struts in the distal end zone of the scoring structure also allows arranging the struts in such a way that they are not distributed all around the cross section of the catheter, so that a large portion of the cross section is strut-free. As a result, the bending capability of the distal end zone of the scoring structure may be improved in at least one direction or orientation. The maneuverability of the scoring catheter may therefore be enhanced, which enables an easier and safer delivery of the catheter to the zone to be treated.

The use of a resilient structure which compensates the shortening of the scoring structure aids the scoring structure to recover the compressed, undeployed shape when the inflatable balloon is deflated.

In an example, the catheter may comprise connectors for connecting longitudinal struts to each other. In an example, the connectors may be U-shaped or S-shaped structures. In an example, connectors between pairs of struts may be joined together to form a circumferential connector with a serpentine ring structure around the balloon. By using connectors a uniform expansion, e.g. an equispaced deployment, of the struts around the balloon may be obtained, avoiding the flaring of the struts. In addition, when the balloon is deflated, the struts may be more easily adapted to the balloon. Similarly, the use of connectors aids the scoring structure to recover the undeployed shape.

In an example, the proximal end of the scoring structure and the distal end of the resilient structure may be coupled together by corresponding matching elements, thereby each structure may be separately manufactured e.g. by injection moulding or by cutting a metallic tube. An independent manufacture of each structure may enable an easier manufacture process.

In an example, the matching elements may be T-shaped elements. In an example, the matching elements may be welded together.

In an example, the resilient structure and the scoring structure are manufactured in a single piece, e.g. they may be laser cut from a tube.

In an example, the internal diameter of the resilient structure may be greater than the internal diameter of the scoring structure in order to allow its elongation during balloon inflation.

In an example, the scoring structure may improve the capacity of the catheter of passing through the obstructed vessel area by having a more reduced diameter at the distal part.

In an example, the proximal end of the resilient structure may be attached to the catheter body and the distal end of the scoring structure is attached to a distal end of the catheter body.

In an example, the scoring structure and resilient structure may be made of a memory shape metal or metal alloy such as Nitinol.

In an example, the scoring structure may comprise a proximal end zone between the scoring zone and the proximal end, and the number of longitudinal struts of the scoring zone may be higher than the number of longitudinal struts in the proximal end zone.

In some examples, the scoring zone may be arranged between two circumferential connectors, each circumferential connector preferably forming a serpentine ring structure around the balloon. The number of longitudinal struts between the two connectors may then be higher than the number of longitudinal struts outside this zone, i.e. outside the scoring zone.

In an example, the scoring zone comprises a connector directly connecting a proximal end zone and the distal end zone and comprising substantially longitudinal struts. In addition, at least part of the area of the distal end and proximal end zones in the proximity of such connector may also provide a scoring effect. That is, the scoring zone may be extended.

In a further aspect, a method for manufacturing a scoring catheter comprising a scoring structure and a resilient structure is provided. The method comprises setting the shape of the scoring structure of the scoring catheter by compressing the scoring structure up to a first diameter smaller than the diameter of the resilient structure and heating the scoring structure during a predetermined period of time.

In an example, the method further comprises compressing a distal end zone of the scoring structure up to a second diameter smaller than the first diameter and heating said distal end zone during a predetermined period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting examples of the present disclosure will be described in the following, with reference to the appended drawings, in which:

Figure 1 schematically illustrates a simplified view of a scoring catheter according to an example;

Figure 2 schematically illustrates a simplified view of the assembly of a resilient structure and a scoring structure for a scoring catheter, according to an example;

Figure 3A illustrates a scoring structure according to an example; Figures 3B - 3D illustrate different cross-sections of a scoring structure according to an example;

Figures 4A and 4B schematically illustrate a distal end zone of a scoring catheter bent according to examples;

Figure 5 schematically illustrates a flat view of an unrolled scoring structure according to an example;

Figure 6 illustrates a cross-section of a scoring structure according to an example;

Figure 7 schematically illustrates a flat view of an unrolled scoring structure according to an example;

Figure 8 shows in perspective a schematic representation of a complementary coupling between the scoring structure and the resilient structure according to an example; and

Figure 9 illustrates a flow chart of a method for manufacturing a scoring catheter comprising a scoring structure and a resilient structure that comprises setting the shape of the scoring structure, according to an example.

DETAILED DESCRIPTION OF EXAMPLES

Figure 1 depicts a scoring catheter 100 which may comprise a catheter body 110, a resilient structure 130 and a scoring structure 140. The scoring catheter 100 may be introduced into the body vessels and be guided through the circulatory system to a zone to be treated i.e. an occluded vessel.

Figure 2 depicts the scoring structure 140 and the resilient structure 130 of Figure 1 prior to assembling the catheter body 110 therein. Figure 3A depicts an enlarged schematic view the scoring structure 140 of Figure 2.

The catheter body 1 10 may comprise a distal end or tip 170 and an inflatable balloon 120. The inflatable balloon 120 may comprise folds to enhance the expansion upon inflation and/or the recovery of the un-deployed shape during deflation. The inflatable balloon may, upon expansion, be used to deploy the scoring structure 140. The inflatable balloon 120 may be made of a flexible material such as polyethylene terephthalate (PET), Nylon, Pebax, a blend or combination of thereof, etc.

The catheter body 110 may also comprise a main internal conduit (not shown) for e.g. a guide wire lumen to enable the catheter to move above the guide wire, and/or an inflation lumen (not shown) to enable the inflation of the inflatable balloon 120. The catheter body 1 10 may be made of any medically suitable material e.g. Nylon, Pebax, polyurethane, polyethylene, a blend or combination thereof, etc.

In an example, the catheter body 1 10 and the inflatable balloon 120 may be made of the same material and may be manufactured by extrusion and blow molding.

The resilient structure 130 shown in Figures 1 and 2 may comprise a proximal end 132 and a distal end 131 , and it may be arranged on the catheter body 110 and proximal with respect to the expandable scoring structure i.e. placed adjacent to the scoring structure but more remote from the distal end or tip. The resilient structure 130 may comprise any shape, e.g. a coiled structure, which enables compensating a shortening of the scoring structure 140 (upon expansion) and maintaining a relatively constant length of the assembly of scoring catheter and resilient structure: i.e. the resilient structure may stretch in length, for example by the separation of the coils, when the scoring structure expands radially and as a consequence becomes shorter in length. The resilient structure 130 may also be a tube of resilient material with a plurality of cuts, slots, or the like.

The scoring structure 140 of Figures 1 and 2, may be arranged around the distal part of the catheter body 1 10. The scoring structure may comprise a distal end zone 144, a proximal end zone 145 and a scoring zone 143. The scoring zone 143 of the scoring structure is intended to contact the wall of a vessel upon its expansion, and may be arranged between the distal and proximal end zones. The distal end zone 144 may comprise a distal end 141 which may be attached to the distal end tip 170 of the catheter body 110 e.g. by welding, by an adhesive or by any other suitable method.

The proximal end zone 145 may comprise a proximal end 142 which may be coupled to the distal end 131 of resilient structure 130 e.g. by welding or by any other suitable method. Therefore, in an example, the distal end 141 of the scoring structure 140 may be fixed to catheter body 110 while the proximal end 142 may be attached to the resilient structure 130 but not to the catheter body 110. This enables the scoring structure to“float” on the balloon at this end, such that the expansion of the scoring structure 140 is facilitated, and the risk of damage during expansion is reduced.

The scoring structure 140 may comprise longitudinal struts 220, 320 substantially parallel to the direction of the axis X: see Figures 2 and 3A - 3D, and more specifically Figures 5 which is a schematic view of a scoring structure 340 unrolled and laid out flat, to show its shape and having one of the struts 320 in each zone (indicated with an arrow in broken lines) "split" between the upper and the lower edge of the figure. The proportions in Figures 3A - 3D and 5 may not be realistic, for a better understanding of the structure.

In examples such as the ones shown in Figures 3A - 3D and 5, the scoring structure 140, 340 may comprise a higher number of longitudinal struts 220, 320 in the scoring zone 143, 343 than (at least) in the distal end zone 144, 344. In the examples of Figures 3A - 3D and 5, there are four longitudinal struts 220, 320 in the scoring zone 143, 343; and only two longitudinal struts 220, 320 in the distal end zone 144, 344 and in the proximal end zone 145, 345. Figures 3B - 3D show different cross-sections of the scoring structure of Figure 3A.

The distal end zone 144, 344 may therefore be compressed to a smaller diameter than the scoring zone, and have an increased crossing capacity, which facilitates guiding the scoring catheter through the vascular system. The friction may also be reduced.

In examples such as the ones of Figures 3A - 3D and 5, the number of longitudinal struts 220, 320 may be less in both the distal end zone 144, 344 and in the proximal end zone 145, 345 than in the scoring zone 143, 343. In the examples, the distal end zone 144, 344 and the proximal end zone 145, 345 comprise two longitudinal struts while the scoring zone 143, 343 comprises four longitudinal struts. The number of longitudinal struts may vary, as long as the scoring zone 143, 343 comprises more struts than at least the distal end zone 144, 344.

In an example, the distal end zone 144, 344; the scoring zone 143, 343 and the proximal end zone 145, 345 may comprise two longitudinal struts 220 along two opposite sides of the balloon defining a first plane, while two additional longitudinal struts 220, 320 may be arranged, only in the scoring zone 143, 343 along two opposite sides of the balloon defining a second plane that is perpendicular to the first plane. In such an arrangement, the four longitudinal struts 220, 320 in the scoring zone 143, 343 are distributed around the circumference of the balloon, at a distance of about 90° from each other, while the two longitudinal struts e.g. in the distal end zone are at a distance of about 180° from each other.

It will be understood that in such a scoring structure 240, 340 the bending capability of the distal end zone with respect to an axis lying on the plane of the two struts 220, 320 (wherein the two struts are curved following the same path, parallel to each other) is much higher than the bending ability with respect to an axis perpendicular to the plane of the two struts (wherein one of the struts is on the outside of the bend while the other strut is on the inside of the bend).

Figure 4A and 4B illustrate this effect, in a scoring catheter with a distal end zone 144 with two struts 221 , 222 and a distal end 141 in a curved region. In Figure 4A the scoring catheter is depicted inside a curve in a body vessel 2, with the two struts 221 , 222 arranged such that one is on the outside of the bend while the other strut is on the inside of the bend, while in Figure 4B the struts 221 , 222 are depicted axially rotated 90° with respect to Figure 4A, and are both curved with the same radius. It is obvious from the figures that in the position of Figure 4B the scoring catheter is much more easily bent.

Indeed, upon bending, the struts 221 , 222 of Figure 4B would both bend in the same way. In contrast, the strut 221 of Figure 4A would need to bend and elongate, and at the same time the strut 222 of Figure 4A would need to bend and contract. The bending capability of the distal zone end 144 in the position Figure 4B with respect to the body vessel 2 would therefore be better, thereby improving the navigability of the scoring catheter. In practice, when navigating through a curve of the vascular system, the scoring catheter with two struts in the distal end zone tends to slightly rotate around its longitudinal axis to accommodate a position in which it curves more easily, i.e. the position of Figure 4B.

In examples such those of Figures 2, 3A - 3D, and 5, the struts 220, 320 of the proximal end zone 145, 345 may be rotated e.g. 90 degrees with respect to the struts 220 of the distal end zone 144, 344 (see Figures 3B and 3D, and Figure 5) thereby being arranged on the second plane perpendicular to the first plane on which the struts of the distal end zone are arranged. Such configuration homogenizes the stiffness and also balances the navigation ability of the scoring structure. With such scoring structure, when the scoring catheter is navigating through the vascular system, the catheter tends to pivot around its own axis as it proceeds through each curve of the vascular system, in order to arrange the struts of the distal end zone in the most favorable position for navigating through the curve i.e. an orientation having a lower advance resistance as a consequence of having less rigidity with respect to the vessel wall. Alternatively or additionally, the user may manually exert a slight torsion on the catheter, to induce it to pivot into the most favorable orientation. Figures 3B and 3D show cross-sections of the distal end zone 144 and of the proximal end zone 145 taken along lines A-A and C-C of Figure 3A, respectively. Figures 3B and 3D show the angle of about 90° between the struts 220 of Figure 3B (arranged in the vertical plane) and the struts 220 of Figure 3C (arranged in the horizontal plane). In addition, the distance of about 180° between the two struts 220 in each of the Figures 3B and 3D, is similarly visible.

Figure 3C shows a cross-section of the scoring zone 143 taken along line B-B of Figure 3A in which the four struts 220 at an angle of 90° from each other are depicted. Figure 5 depicts an enlarged schematic view of the scoring structure 340 unrolled and laid out flat.

It will thus be understood that with examples of the present scoring structure a scoring operation may be performed efficiently, using a relatively large number of struts, while at the same time the safe delivery of the scoring catheter through the vascular system is facilitated by having a smaller number of struts in the distal end zone.

In some examples, the struts 220 may comprise a cross section having side walls which may be substantially corradial to the radial axis of the scoring catheter (see Figures 3B - 3D) that is, each side wall may extend on a radius of the radial axis.

In other examples, the cross-section of struts 220 may comprise side walls not substantially corradial to the radial axis of the scoring catheter. Figure 6 depicts a cross-sectional view of a scoring structure in which the struts 220b may comprise e.g. a trapezoidal cross-section having the surface to be in contact with the plaque once the scoring catheter is at the zone to be treated may be narrower than the surface to be facing the inflatable balloon. In addition, the surface of the strut to be in contact with the vessel wall, i.e. with the plaque in the zone to be treated, may also be narrower than in other examples and, upon inflation of the balloon, the force exerted by the balloon may be concentrated in a more reduced surface, thereby improving the scoring effect.

Suitable markers, e.g. radiopaque markers, may be provided on the scoring catheter to monitor the position of the struts and control the angular position of the scoring catheter accordingly.

The scoring structure 140, 340 may further comprise connectors 230, 330 (see Figures 2 and 5) that connect at least one longitudinal strut 220, 320 to another, thereby facilitating both the even and orderly expansion of the scoring structure 140, 340 when the inflatable balloon 120 is inflated and the recovery of the compressed, undeployed shape when the inflatable balloon is deflated. In addition, the flaring of the longitudinal struts may be avoided during the delivery of the scoring catheter. In addition, at least the zone of the connectors in the proximity of the scoring zone may also provide a scoring effect i.e. may provide an extended scoring zone.

The connectors 230 may connect two struts or more, and they may be of any suitable shape e.g. S-shaped, U-shaped, sinusoidal, serpentine, etc. or a combination thereof, provided that they enhance and/or facilitate the expansion of the scoring zone e.g. in a uniform manner. Additionally, the connectors may be arranged so as to form circumferential connectors, for example circumferential ring structures 310 (see Figure 5) around the balloon.

The connectors may be a combination of any of the disclosed shapes and examples.

In cases having a balloon length e.g. of about 6 mm and a diameter of about e.g. 1.5 - 3.5 mm, or in examples having a balloon length e.g. of about 8 mm and a balloon diameter of e.g. about 1.5 - 3.5 mm, the scoring structure may comprise a single connector.

The present disclosure also provides a scoring catheter for scoring plaque on a body vessel, with a catheter body, an inflatable balloon arranged on the catheter body, an expandable scoring structure arranged on the balloon and comprising a distal end, a proximal end, a scoring zone to contact the wall of a vessel, and a distal end zone between the scoring zone and the distal end, and a resilient structure arranged on the catheter body and proximal with respect to the expandable scoring structure to compensate a shortening of the scoring structure upon expansion, the resilient structure having a distal end attached to the proximal end of the scoring structure, and a proximal end, wherein the scoring structure comprises substantially longitudinal struts, and wherein the number of struts in the scoring zone is higher than the number of struts in the distal end zone, and wherein the scoring zone comprises a connector directly connecting a proximal end zone and the distal end zone.

Examples of this scoring catheter may be provided with any of the features disclosed herein for other example scoring catheters, provided these features are compatible with this device.

Figure 7 depicts a scoring structure 440 according to this example, comprising a distal end zone 444, a proximal end zone 445 and a scoring zone 443. The scoring zone of the example may comprise a single connector 430 for directly connecting the proximal end zone 445 and the distal end zone 444. The connector 430 may comprise substantially longitudinal struts 450 which may have rounded ends connected to the struts of the distal and proximal end zones. The struts of the connector may extend in a substantially longitudinal direction but be slanted, as in Figure 7, so each strut 450 of the connector has one end coupled to a strut 421 or 422 of the proximal end zone, and the other end coupled to a strut 423 or 424 of the distal end zone, where the struts 421 , 422 of the proximal end zone are not aligned with the struts 423, 424 of the distal end zone. In the figure, the struts 422, 423 in proximal and distal end zones respectively (indicated with an arrow in broken lines) are shown "split" between the upper and the lower edge of the figure. As in other disclosed examples, the number of struts in the scoring zone may be greater than at least in the distal end zone. The proportions in Figure 7 may not be realistic, for a better understanding of the structure.

In addition to the connector, the scoring effect may also be provided by part of the distal and proximal end zones in the proximity of the connector, thereby providing an extended scoring zone.

In other examples, wherein the balloon length is about 10 - 15 mm and the balloon diameter about 1.5 - 3.5 mm, the scoring structure may comprise two connectors. In addition, the scoring structure may also comprise two struts in examples comprising a balloon length of about 8 mm and a balloon diameter about 1.5 - 3.5 mm. In an example, the scoring structure 140 and the resilient structure 130 may comprise different internal diameter i.e. the internal diameter of the resilient structure 130 may be greater than the internal diameter of the scoring structure 140. In an example, the external diameter of the resilient structure may be greater that the external diameter of the scoring structure

The internal diameter of the scoring structure 140 may be any diameter which enables a catheter body comprising a deflated balloon to be arranged within. Besides, the internal diameter of the resilient structure 130 may be any that enables a catheter body 1 10 to be arranged within. In an example, the distal part of scoring structure 141 may comprise an outer diameter of about 0.7 mm and the scoring zone 143 may comprise an outer diameter of about 0.9 mm, while the resilient structure 130 may have an outer diameter of about 1.2 mm. A scoring catheter having a more reduced outer diameter at distal part 141 and scoring zone 140 than at the resilient structure 130 facilitates passing through the occluded vessel as the crossing profile is decreased.

In an example, the diameter difference between the scoring and the resilient structures may create a gradual gradient e.g. a funnel shape gradient.

In an example, the scoring and resilient structures 140, 130 may be manufactured, e.g. from a tube, as a single piece or element. The tube may be laser-cut to form the desired shape of the scoring structure and the resilient structure.

In an alternative example, the resilient structure 130 and the scoring structure 140 may be independently or separately manufactured and then attached together by any suitable method e.g. welding, adhering, etc., thus obtaining a single piece. The scoring structure and the resilient structure may be attached by joining the proximal end 142 of the scoring structure 140 and the distal end 131 of the resilient structure 130.

In an example (see Figure 8), the distal end 131 of the resilient structure 130 and the proximal end 142 of the scoring structure 140 may comprise T-shaped complementary couplings.

Figure 8 shows an example of a detail in perspective of one side of the connection between distal end 131 of the resilient structure and the proximal end 142 of the scoring structure which comprise T-shaped complementary couplings. The figure is schematic and only shows the zone of the coupling, cut from the rest of the device. In the example, the distal end 131 of the resilient structure may comprise a T-shaped recess 138 while the proximal end 142 of the scoring structure may comprise a protruding T-shaped portion 148. In order to strengthen the coupling between the resilient structure and the scoring structure, the complementary coupling may be welded together after matching the complementary couplings. The scoring structure 140 and resilient structures 130 may be provided with a pair of complementary couplings arranged at opposite sides.

The scoring structure 140 and the resilient structure 130 may be made of a memory shape material, e.g. a metal or metal alloy such as Nitinol. In an example, at least the scoring structure 140 may additionally be coated e.g. with a drug eluting coating.

The catheter body 110 may be arranged within the resilient and scoring structures 130, 140 by introducing the distal part of the catheter body along the length of the resilient structure 130 and up to the distal end 141 of the scoring structure 140 as in the example of Figure 1. In examples having an internal diameter difference between the scoring structure and the resilient structure, the reduced diameter of the scoring structure facilitates crossing the occluded zone of the vessel, i.e. due to the plaque, as the crossing profile of the catheter is reduced.

The distal end 141 of the scoring structure 140, and the proximal end 132 of the resilient structure 130 may then be attached to the catheter body 1 10, and the scoring catheter 100 may be compressed to a suitable condition to be delivered to a treatment site in the vascular system.

In a method for scoring plaque on a vessel, the compressed scoring catheter 100 may be introduced into a body vessel and guided through the vascular system to a zone to be treated, i.e. an occluded vessel.

In the navigation to the treatment site, for example when the tip 170 of the catheter body reaches a curve in a blood vessel, the scoring catheter 100 may slightly pivot into an angle around its own longitudinal axis, until the struts 220 of the distal end zone 144 of the scoring structure 140 are placed in a favorable position according to the direction of the curve of the blood vessel, for facilitating bending of the distal end zone 144 of the scoring structure in the direction of the curve.

Once the catheter is placed in the zone to be treated, the inflatable balloon 120 may be inflated thereby causing the scoring structure 140 to expand and the longitudinal struts 220 to score the plaque on the wall of the vessel. The scoring zone 143 of the scoring structure 140 may therefore contact the vessel wall and score the plaque thereby creating new paths or broadening the existing conduit for increasing the blood flow. The obstruction may thereby be reduced and the occlusion zone may be prepared for a possible subsequent treatment e.g. by deploying a stent or by compressing the plaque with an expandable balloon. Upon the expansion and consequent shortening of the scoring structure 140, the resilient structure 130 may adapt its length, i.e. it may stretch, to compensate the shortening of the scoring structure 140 and maintain the same length of the assembly.

In some examples of the method, several inflation/deflation cycles of the balloon 120 may be carried out in order to prepare the plaque for a subsequent treatment. Once the scoring of the plaque is prepared for a subsequent post-treatment, the balloon may be deflated, such that the scoring structure returns to a compressed condition and the scoring catheter 100 may be removed from the body vessel.

In a manufacturing method, the scoring and resilient structures 140, 130 may be cut simultaneously in a single piece e.g. from a metallic tube, or they may be cut separately and then coupled together e.g. by welding, by adhesion or by any other suitable method. A shape-setting thermic treatment may then be carried out for defining the shape of the scoring structure 140 and/or the resilient structure 130.

Figure 9 is a flow chart of the steps of a shape-setting thermic treatment in a manufacturing method. In block 901 , the scoring structure 140 may be compressed up to a first diameter e.g. of about 0.9 mm and then, in block 902, heated during a predetermined period of time of e.g. about 2 minutes, at e.g. 500 - 600 °C.

The scoring structure may later be cooled or allowed to cool. As a result, the scoring structure may maintain a compression diameter which facilitates guiding the scoring catheter 100 through the circulatory system.

In an example, the shape setting process may further comprise a step, in block 903, in which the distal end zone 144 of the scoring structure is processed e.g. so as to adapt to the inflatable balloon. The distal end zone 144 may be compressed up to a second diameter e.g. of about 0.7 mm and heated during a predetermined period of time e.g. 2 minutes, at e.g. around 500 - 600 °C. Although only a number of examples have been disclosed herein, other alternatives, modifications, uses and/or equivalents thereof are possible. Furthermore, all possible combinations of the described examples are also covered. Thus, the scope of the present disclosure should not be limited by particular examples, but should be determined only by a fair reading of the claims that follow. If reference signs related to drawings are placed in parentheses in a claim, they are solely for attempting to increase the intelligibility of the claim, and shall not be construed as limiting the scope of the claim.

Claims

1. A scoring catheter for scoring plaque on a body vessel, comprising:

a catheter body,

an inflatable balloon arranged on the catheter body,

an expandable scoring structure arranged on the balloon and comprising a distal end, a proximal end, a scoring zone to contact the wall of a vessel, and a distal end zone between the scoring zone and the distal end, and

a resilient structure arranged on the catheter body and proximal with respect to the expandable scoring structure to compensate a shortening of the scoring structure upon expansion, the resilient structure having a distal end attached to the proximal end of the scoring structure, and a proximal end,

wherein the scoring structure comprises longitudinal struts, and wherein the number of longitudinal struts in the scoring zone is higher than the number of longitudinal struts in the distal end zone.

2. The scoring catheter according to claim 1 , further comprising connectors for connecting longitudinal struts to each other.

3. The scoring catheter according to claim 2, wherein the connectors are U-shaped or S-shaped.

4. The scoring catheter according to any of claims 2 or 3, wherein the connectors form serpentine ring structures around the balloon.

5. The scoring catheter according to any of claims 1 - 4, wherein the proximal end of the scoring structure and the distal end of the resilient structure are coupled together by corresponding matching elements.

6. The scoring catheter according to claim 5, wherein the matching elements are T- shaped elements.

7. The scoring catheter according to any of claims 1 - 3, wherein the resilient structure and the scoring structure are manufactured in a single piece.

8. The scoring catheter according to any of claims 1 - 7, wherein the proximal end of the resilient structure is attached to the catheter body and the distal end of the scoring structure is attached to a distal end of the catheter body.

9. The scoring catheter according to any of claims 1 - 8, wherein the scoring structure and resilient structure are made of a memory shape metal or metal alloy, preferably Nitinol.

10. The scoring catheter according to any of claims 1 - 9, wherein the scoring structure comprises a proximal end zone between the scoring zone and the proximal end, and wherein the number of longitudinal struts of the scoring zone is higher than the number of longitudinal struts in the proximal end zone.

1 1. The scoring catheter according claim 10, wherein the scoring zone comprises four struts and the distal and proximal end zones comprise two struts.

12. The scoring catheter according to any of claims 2 - 11 , wherein the scoring zone is arranged between two circumferential connectors, each circumferential connector preferably forming a serpentine ring structure around the balloon.

13. The scoring catheter according to any of claims 1 or 4 - 12, wherein the scoring zone comprises a connector directly connecting a proximal end zone and the distal end zone and comprising substantially longitudinal struts.

14. A method for manufacturing a scoring catheter comprising an expandable scoring structure and a resilient structure, the distal end of the resilient structure being attached to the proximal end of the expandable scoring structure, the method comprising setting the shape of the scoring structure of the scoring catheter, by:

compressing the scoring structure up to a first diameter smaller than the diameter of the resilient structure; and

heating the scoring structure during a predetermined period of time.

15. The method according to claim 14, further comprising compressing a distal end zone of the scoring structure up to a second diameter smaller than the first diameter, and heating said distal end zone during a predetermined period of time.