WO2016056929A1

WO2016056929A1 - Intravascular system for protection of blood vessels

Info

Publication number: WO2016056929A1
Application number: PCT/PL2015/000161
Authority: WO
Inventors: Emil PŁOWIECKI; Leszek HUKALA
Original assignee: Balton Sp. Z O.O.
Priority date: 2014-10-07
Filing date: 2015-10-07
Publication date: 2016-04-14
Also published as: PL233561B1; PL409730A1

Abstract

An intravascular system for protection of blood vessels has been presented, comprising a proximal part and distal part with a filtration element, characterised in that the filtration element situated behind the soft tip (12) comprising from the distal side of the system a filtration section (a) followed by an open part (b) is fit onto an inner tube (3), which at least in the area located inside this filtration element is ununiform and comprises at least one elastic distal part (3.1) or a fragment thereof, located in the filtration section (a), at least one rigid part (3.2) located in the transitional area connecting the filtration section (a) to the open part (b) and at least one elastic proximal part (3.3) or a fragment thereof, located in the open part (b).

Description

Intravascular system for protection of blood vessels

The object of the invention is an intravascular system for protection of blood vessels. The invention relates to the field of medical devices (e.g. from the catheter group), introduced percutaneously into the patient's body e.g. via the femoral or radial artery in order to position the system in a location where there is a risk of occurrence of embolic material transported along with biood, possible to block the blood vessels. The intravascular system comprises a filter in the form of a filtration element with usually circular cross-section, due to which protection of blood vessels is ensured by stopping the thrombi inside the filter, along with other embolic elements contained within the blood flowing through the filter.

Currently, when conducting several types of medical procedures, vascular filters are used to prevent strokes. For example, during balloon angioplasty procedures, when filling the balloon, in a narrowed blood vessel may occur detachment of embolic material from the vessel walls, which may subsequently block the clearance of the smaller vessel and cause an embolism. On the other hand, surgical procedures conducted e.g. within the veins of the lower limbs may sometimes cause the occurrence of pulmonary embolism. The use of a vascular filter is also recommended when conducting the procedures of removal of implanted electrodes from the heart, which with time were subject to damage or dislocation or are being replaced by different new electrodes. The removal of an electrode may cause tissue and thrombus particles to be released, which may result in e.g. a pulmonary embolism.

From an international application description WO9833443A1 an intravascular catheter is known, comprising a basket-shaped filter with a filtration membrane for removal of embolic material from the vessels. The catheter has a construction enabling assembly and disassembly of the filter, which is mounted at a distal end of the guidewire right behind a rounded soft ending of the catheter enabiing its prompt, atraumatic insertion into the vessel. From an international application description W09923976A1 (Polish application P.340258), a device for protection of blood vessels against embolic material is known, provided with a foldable filtering element mounted at the guidewire. The filtering element is provided with a body whose inlet end is provided with at least one inlet aperture, with dimensions enabling entry of both blood and embolic material inside it, and the outlet end - with a large number of outlet apertures with dimensions enabling passing of blood and stopping of the embolic material. When the procedure is over, the catheter is moved along the guidewire to the proximal end of the filtering element, closing its inlet apertures to prevent moving onto the remaining part of this element, causing gradual folding of the body of the filtering element from the proximal to the distal end, in order to remove it from the patient's body. The filtering element may be mounted on a tubular cylinder, moved and rotated around the guidewire between the stop and the clamping guidewire ring located apart from each other, due to which it is possible to manipulate the guidewire regardless of the filtering element, preferably within a range amounting to between 100 and 50 mm along the axis of the catheter.

From the USA patent description US6375670B1 a catheter is known provided with a filtering element in the form of a basket woven from metal wires in such a manner that it can easily assume two forms - assembled and disassembled. One end of the filtering element has been woven keeping the openings large to enable the inflow of blood along with the embolic material. The second part of the filtering element is woven more densely and it stops the thrombi. The filtering element can inside comprise a flexible element connecting its two ends.

The known catheters for protection of blood vessels, comprising a filtering element, in spite of their varying construction may be inefficient while being closed and drawn out of the vessel, because sometimes escape of the thrombi from the filter is observed (which has been mentioned in the abovementioned publication W09923976A1). Also, precise, central positioning of the filter in the clearance space of a blood vessel is troublesome and may cause incomplete or unsymmetrical opening of the filtering element. Known catheters with a filtering element are often not provided with an inner tube, which constitutes a guidewire channel and it is impossible to control the catheter in an easy and simple manner.

It is therefore desirable to develop an improved construction of the catheter with a filtering element enabling to achieve reliability of the device. It is also recommended to suggest a more complex, universal intravascular system consisting of subassemblies, as a whole serving several functions during the procedure.

The object of the invention is an intravascular system for the protection of blood vessels, comprising a proximal part and a distal part with a filtration element, characterised in that, the filtration element situated behind the soft tip, comprising from the distal side of the system a filtration section followed by an open part, is mounted on an inner tube, which at least in the area located inside this filtration element is ununiform, and comprises at least one elastic distal part or a fragment thereof, located in the filtration section, at least one rigid part located in the transitional area connecting the filtration section to the open part, and at least one elastic proximal part or a fragment thereof, located within the open part.

The filtration element is mounted on the inner tube by means of a distal mounting cylinder, which is connected to the distal elastic part of the inner tube, and a proximal mounting cylinder, which is connected to the proximal elastic part of the inner tube.

The filtration section has the form of a filtration mesh composed of multiple wires opening out from the proximal side of the system into an open part created by the arms of the filtration mesh.

The outer tube is positioned along the whole system, and along with the through inlet channel created in the soft tip and the outlet channel creates a channel for the guidewire.

There are markers located in the area where the filtering part opens out into an open part of the filtering element.

The system comprises an inlet tube with a smaller diameter and an outlet tube with a larger diameter, situated coaxially one inside another.

The outlet tube is slidingly fit on the inlet tube, which constitutes a support for the outlet tube. The rigid part of the inner tube is situated in the marker location area within the filtration element, when it assumes the folded position in the inlet tube.

An embodiment of the object of the invention has been presented in a drawing, where fig. 1 presents a general view of the system with the filtration element in the form of an open basket projecting from the inlet tube, fig. 2 shows a magnified transverse section A-A of the system (referenced in fig. 1 ) with a visible section of the concentrically situated inner tube, inlet tube and outlet tube, fig. 3 presents a magnified distal part of the system comprising the unfolded filtration element comprising the filtration mesh, and fig. 4 presents a magnified distal part of the system with the filtration element comprising an embolic element intercepted in the blood vessel.

The intravascular system 1 for protection of blood vessels comprises a proximal part and a distal part with a filtration element (referenced in fig. 3 as area a+b), which according to the invention is situated behind the atraumatic soft tip 12, in its direct vicinity. The filtration element has the form of a foldable basket and comprises from the distal side of the system, i.e. from the side which is the first to enter the patient's body, a filtration section a, preferably shaped as a spherical sector or half of a sphere or in a rounded shape, followed by the open part b, which has no filtration function and in which are located the arms 2.1 supporting the filtration mesh 2. The open part b fixes and/or stabilises the filtration section a. The filtration element is fixed at its two ends, from the outside to the inner tube 3, which at least along the segment located inside the filtration element is ununiform and comprises in area a+b at least three parts - in sequence: the elastic distal part 3.1 (or at least a fragment thereof), located in the filtration section a, the rigid part 3.2 located between the filtration section a and the open part b as well as the elastic proximal part 3.3 (or at least a fragment thereof), located in the open part b of the filtration element. The term that at least fragments of the elastic parts 3.1 and 3.3 are located in the area of the filtration section a and the open part b, means that the elastic parts may extend outside the filtration element, so that they terminate only in a place located outside of the filtration element. The elastic segments of the tube 3 preferably have the form of a flexible spiral (spring), which may in a reversible manner change its length (be expanded) and bend. Ununiformness of the tube 3 along the segment located inside the filtration element may be therefore obtained by processing the outlet tube in such a manner that elastic i.e. spiral areas will be created. The inner tube 3 may be ununiform in such a manner that along its length it comprises several elastic areas, which improves the abilities of operating the whole system and the guidewire inside the tube 3, the tube 3 preferably comprising at least one elastic part located in the area of the filtration section and in the open part as well as in the transitional segment, located between these parts, comprising at least one rigid part. It is however possible that the inner tube 3 in the area, where the filtration element is located, comprises interchangeably several elastic 3.1 , 3.3 and rigid 3.2 areas.

For the needs of the present invention the term "ununiform" means that the inner tube 3 comprises areas of varying physical properties, i.e. elastic areas of variable length (reversib!y expandable) and rigid areas in the form of an unprocessed tube.

The inner tube 3 may be made of metal or plastic, and also have areas made of metal connected to areas made of plastic.

The filtration element in the form of a basket is fixedly mounted onto the pipe 3 on its two ends (distal and proximal) by means of two mounting cylinders: distal 5.1 , which is connected to the distal elastic part 3.1 of the tube 3, and proximal 5.2, which is connected to the proximal elastic part 3.3 of the tube 3. Mounting cylinders 5.1 and 5.2 may be mounted on the elastic ends of parts 3.1 and 3.3 of the tube 3, i.e. parts 3.1 and 3.3 of the tube 3 are elastic only to the mounting place of the cylinders 5.1 and 5.2, inside the filtration element, or, more preferably, parts 3.1 and 3.3 remain elastic outside of the mounting place of the cylinders 5.1 and 5.2 (outside of the area of filtration element a+b), meaning that the elastic properties of the tube 3 are retained in a certain part, also outside of the mounting place of the abovementioned cylinders. The tube 3 may be in two mounting places of the filtration element (in mounting places of cylinders 5.1 and 5.2) specifically for this purpose adjusted due to its construction, e.g. it may comprise concave channels or apertures for fixing wires constituting the components of the filtration element.

Fixed mounting of the filtration element on the tube 3 means that free movement of the filtration element in relation to the tube 3 is impossible at any degree. In other words, folding and unfolding of the filtration element is possible only via interaction with the inner tube 3, by the movement of its elastic parts.

The filtration element, meaning the filtration mesh 2 and its arms 2.1 is preferably made of materials belonging to the group of materials exhibiting the shape memory effect, for example of interwoven nitinol wires. Other materials may be also used, e.g. steel and/or other metals not exhibiting the shape memory effect, as well as plastic. The arms 2.1 may be made of other material than the filtration mesh 2. Either both these parts or one of them may be made of many interconnected materials, e.g. the mesh 2 may comprise a frame made of metal wires, on which the plastic filtration material may be mounted.

The interwoven wires (or fibres of other material) of adequate weaving density (mesh density) form a filtration mesh 2 shaped as a bowl. The mesh 2 size is different in individual parts of this mesh 2 and the densest weave (smallest mesh size) is reached at the top of the filtration mesh 2, in its distal part, at the greatest distance from the arms 2,1 ,

An example of the bowl weave has been shown in fig. 3, where six wires forming the arms 2,1 of the mesh 2 in its open part (referenced in fig. 3 as part b) diverge into twelve wires (each of the six arms 2.1 is connected to two wires), and subsequently each of the twelve wires diverges again into two wires, which in total allows obtaining a structure made of twenty four wires. The mesh 2 therefore has gradually increasing density towards its distal end. The proximal part of the filtration element has eyelets of the largest size and remains open for the embolic material, which from this side enables free inflow of blood which is filtrated in the filtration section (referenced in fig. 3 as part a), particularly on its top, with the highest density of the eyelets. The presented structure of the filtration element is only an example and different construction may be anticipated, e.g. other arrangement of nitinoi wires is possible, and the mesh 2 may be supported by 3 to 10 arms 2.1, which radially fix it to the inner tube 3. It is also possible to form a filtration element from a separate part of other kind of filtration material, which would be supported by several arms 2.1.

In fig. 3 an example has been presented for the construction of the filtration element, in which the mesh 2 weave (bowl) has been connected in six points along its perimeter with the six arms 2.1 , and in the connection areas markers 4 visible in X-Ray have been used in the form of clamping cylinders, in the location of subsequent divergences of wires forming the mesh 2 may be located markers 4' placed in a long row (in the proximal part of the mesh 2). In a preferable embodiment of the invention both ends of nitinoi wires forming the filtration element are connected to each other (pressed together) and to the inner tube 3, along its outer perimeter, with mounting cylinders 5.1 and 5.2. It is also possible to connect the filtration element directly to the individual parts of the inner tube 3, without the use of cylinders 5.1 and 5.2 e.g. via a glued or welded connection.

The inner tube 3 constitutes a channel for guidewire 14, it is extended along the whole length of the system and is ended at the distal side with an inlet channel 13.1 constituting a through opening in the soft tip 12 and an outlet channel 13.2 at the proximal side of the system (at the operator's side), constituting a through opening in the cap 11. It is possible that the tube 3 is made of one piece of material, but it is also possible that it would be obtained by connecting elastic parts to rigid parts.

The system is introduced into a blood vessel in a position where the filtration element has the smallest diameter, it is closed (folded) and in its entirety placed in the inlet tube 6. In such configuration the elastic distal part 3.1 and elastic proximal part 3.3 of the tube 3 expand and increase their length, due to which the filtration mesh 2 along with the arms 2.1 concurrently folds and elongates so that all its elements adjoin the tube 3. The markers 4 and 4' are then located in the area of the rigid part 3.2 of the tube 3. The rigid part 3.2 neutralises the pressure of the abovementioned markers against the guidewire located in the inner tube 3. The term that the markers 4, 4' are located in the rigid part "area" 3.2 is to be understood as any location of the markers along the rigid part 3.2.

Such construction of the filtration element enables efficient folding and unfolding of the filtration mesh 2. The filtration element has in its central segment (corresponding to the locations of the rigid part 3.2 of the tube 3) the most complicated construction, i.e. in this part are located the divergences (weaves) of the filtration mesh and the markers 4, 4', therefore the smooth, straight and rigid part 3.2 of the tube 3 eliminates the risk of tangling the filtration mesh while unfolding it. Due to the rigid part 3.2, introducing the guidewire 14 into and drawing it out of the system is also facilitated, since a too long elastic segment of the tube 3 could obstruct the moves of the guidewire.

After a performed procedure, the filtration mesh 2 comprises inside an embolic element 15 and the filtration element often cannot again return to its default size, which is why the system is also provided with an outlet tube 7 with a larger diameter than the inlet tube 6. The tubes 6 and 7 are slidingly fit, and the tube 6 with smaller diameter comprises a support for the exit tube 7 (tube 6 supports tube 7). The filtration element is drawn out of the blood vessel in the tube 7 and the tube 6 during this stage of the procedure remains in a position which it assumed while releasing the filtration element. Fig. 4 presents the stage of drawing the system out of the vessel, in which the tube 7 is fit from the proximal side, i.e. from the side of the arms 2.1 , onto the filtration element filled with the embolic material.

In the proximal part, located during the procedure outside of the patient's body, the system is provided with caps for the operator, which enable operation of individual parts, i.e. components of the system. The system according to the invention preferably may consist of three assemblies, but in the simplified type it may lack the outlet system of the filtration element.

The inlet assembly of the filtration element comprises an inlet tube 6, a cap 10 of the inlet assembly and a "Y" cap 9.2 of the inlet assembly. The outlet assembly of the filtration element comprises an outlet tube 7, a cap 8 of the outlet assembly and a "Y" cap 9.1 of the outlet assembly. The assembly of the filtration element comprises the filtration element fit onto the inner tube 3 and a cap 11 of the filtration element assembly.

In the system according to the invention, mounting cylinders 5.1 and 5.2 may be used, made of material visible in X-Ray. Also the soft tip 12 may be made of such material visible in X-Ray. The inlet tube 6 and the outlet tube 7 may at their distal ends comprise markers visible in X-Ray.

The system with the filtration element, according to the invention, is preferably introduced along the guidewire, which highly facilitates precise and safe operation of the device during the whole procedure. The guidewire is the first to be guided through blood vessels, it is therefore possible to introduce the system even through narrowed segments of the vessels. The elements of the system, particularly the construction of the filtration element have been adjusted to interact with the guidewire. The presented construction of the system also ensures stable, central positioning of the filtration element. Due to the inner tube used in the system, ununiform in its properties, comprising an elastic section (reversibly expandable) in the mounting area of the filtration element, this element easily reaches during operation its intended unfolded position. The inner tube is adjusted in its structure to the structure of the filtration element, and at the same time it may also constitute a channel for guidewire. The assembly of two inlet and outlet tubes, placed one inside the other, enables drawing the system out of the vessel with the filled filtration element in a casing of larger diameter, making the dangerous in its effects releasing of the thrombi back into the vessel impossible. Preferable effects are also obtained due to the fact that the system according to the invention is compact, i.e. it comprises the inlet assembly and the outlet assembly of the filtration element interacting with each other and there is no necessity to introduce and draw out two separate systems during the procedure, which in the area where the procedure is conducted may cause unwanted side effects and secondary release of the embolic material.

The soft, atraumatic distal tip, used in the system, enables precise and safe introduction of the system into the blood vessel.

References on drawings: 1 Intravascular system with filtration element for protection of blood vessels

2 Filtration mesh

2.1 Arms of the filtration mesh

3 Inner tube

3.1 Elastic distal part of the inner tube

3.2 Rigid part of the inner tube

3.3 Elastic proximal part of the inner tube

4 Marker

4' Second row marker

5.1 Distal mounting cylinder

5.2 Proximal mounting cylinder

6 Inlet tube

7 Outlet tube

8 Outlet assembly cap

9.1 Outlet assembly Ύ" cap

9.2 Inlet assembly Ύ" cap

10 Inlet assembly cap

11 Filtering element assembly cap

12 Soft tip

13.1 Inlet channel of the guidewire

13.2 Outlet channel of the guidewire

14 Guidewire

15 Embolic element

a Filtration section of the filtration element

b Open part of the filtration element

Claims

1. intravascular system for protection of blood vessels comprising a proximal part and a distal part with a filtration element, characterised in that the filtration element situated behind the soft tip (12), comprising from the distal side of the system a filtration section (a) followed by an open part (b) is fit onto an inner tube (3), which at least in the area located inside this filtration element is ununiform, and comprises at least one elastic distal part (3.1 ) or a fragment thereof, located in the filtration section (a), at least one rigid part (3.2) located in the transitional area, connecting the filtration section (a) to the open part (b) and at least one elastic proximal part (3.3) or a fragment thereof, located in the open part (b).

2. Intravascular system according to claim 1 , characterised in that the filtration element is fit onto a tube (3) by means of a distal mounting cylinder (5.1), which is connected to the distal elastic part (3.1) of the tube (3) and the proximal mounting cylinder (5.2), which is connected to the proximal elastic part (3.3) of the inner tube (3).

3. Intravascular system according to claim 1 or 2, characterised in that the filtration section (a) has the form of a filtration mesh (2) composed of multiple wires opening out from the proximal side of the system into an open part (b) created by the arms (2.1) of the filtration mesh (2).

4. Intravascular system according to claim 1 or 2 or 3, characterised in that the inner tube (3) is positioned along the whole system and along with the through inlet channel (13.1) created in the soft tip (12) and the outlet channel (13.2) creates a channel for the guidewire (14).

5. Intravascular system according to claim 1 or 2 or 3 or 4, characterised in that there are markers (4, 4') located in the area where the filtering part (a) opens out into an open part (b) of the filtering element,.

6. Intravascular system according to any of the claims 1 to 5, characterised in that it comprises an inlet tube (6) with a smaller diameter and an outlet tube (7) with a larger diameter, situated coaxially one inside the other.

7. Intravascular system according to any of the claims 1 to 6, characterised in that the outlet tube (7) is slidingly fit on the inlet tube (6), which constitutes a support for the tube (7).

8. Intravascular system according to any of the claims 1 to 7, characterised in that the rigid part (3.2) of the inner tube (3) is situated in the location area of the markers (4, 4') in the filtration element, when it assumes the folded position in the in!et tube (6).