Device for endovascular treatment

Abstract

There is provided a device (100) for removing a clot from a vessel. The device (100) comprises a catheter body (110), a set of holes (120) and a lumen (130). The catheter body (100) is for insertion into the vessel. The catheter body (110) is attachable to an aspirator at a proximal end (111) of the catheter body (110). The catheter body (110) comprises an interior surface and an exterior surface. The catheter body (110) comprises a lumen (130) extending between the proximal end (111) and a distal end (112). The lumen (130) is configured to receive a guidewire (300). The set of holes (120) is towards the distal end (112) of the catheter body (110) in a distal region. The set of holes (120) is configured to engage the clot by suction. The set of holes (120) is arranged circumferentially on the catheter body (110). The distal region comprises a valve region (114) including a valve (115). The valve (115) is configured to close in response to pressure within the lumen being below a threshold value.

Description

[0001] Device for Endovascular Treatment

[0002] The present disclosure relates to a device for removing a clot from a vessel.

[0003] BACKGROUND

[0004] Each year millions of people suffer from strokes resulting from bloods clots in the brain, leading to death or disability. Pharmaceutical methods have been developed for treating clots. However, some clots are not responsive to known pharmaceutical methods. Therefore, recent years have seen the development of mechanical thrombectomy techniques. Mechanical thrombectomy techniques have the advantage over pharmaceutical methods of being effective after the efficacy window for pharmaceutical methods has passed, for example.

[0005] The two principal mechanical thrombectomy methods are: (i) using a catheter to apply a vacuum to a clot to ingest the clot (aspiration) and (ii) using a stent to snare and extract the clot. Use of a stent may cause trauma to the vessel, especially if the vessel is small. On the other hand, aspiration devices often include catheters that are too large to reach clots in smaller vessels. Catheters that are small enough to reach clots in smaller vessels are typically unable to apply strong enough pressure and / or force to remove the clot. Further, it is not uncommon for the clot to fragment when it is attempted to extract a clot using an aspiration device or using a stent.

[0006] Hence, there is a need for a device that can reach smaller, distal vessels and that is also able to apply a sufficiently strong pressure and / or force to successfully remove clots therefrom without causing fragmentation of the clot.

[0007] SUMMARY

[0008] According to a first aspect there is provided a device for removing a clot from a vessel. The device comprises a catheter body, a set of holes and a lumen. The catheter body is for insertion into the vessel. The catheter body is attachable to an aspirator at a proximal end of the catheter body. The catheter body comprises an interior surface and an exterior surface. The catheter body comprises a lumen extending between the proximal end and a distal end. The lumen is configured to receive a guidewire. The set of holes is towards the distal end of the catheter body in a distal region. The set of holes is configured to engage the clot by suction. The set of holes is arranged circumferentially on the catheter body. The distal region comprises a valve region including a valve. The valve is configured to close in response to pressure within the lumen being below a threshold value.

[0009] At least one of the set of holes may be a frustoconical hole.

[0010] The at least one frustoconical hole may have a greater diameter at the exterior surface of the catheter body compared with at the interior surface of the catheter body.

[0011] The diameter of the at least one of the set of holes at the interior surface may be 0.05 to 0.26 mm and at the exterior surface may be 0.12 to 0.51 mm.

[0012] The distal region may comprise a tapered portion.

[0013] The valve region may comprise a distal aperture, and the distal aperture may be frustoconical.

[0014] The set of holes may be distributed radially with respect to a longitudinal axis of the lumen, and an angular spacing between adjacent holes may be 180 degrees or less.

[0015] The set of holes may be distributed along an engagement zone in the distal region, and the set of holes may have a spatial distribution of 4 to 16 holes per mm of length of the engagement zone.

[0016] The set of holes may form a helicoidal pattern, a double-helicoidal pattern or diamond-shaped pattern.

[0017] The device may further comprise at least one of: a radiopaque element and a hydrophilic coating.

[0018] The set of holes may be distributed along the tapered portion. The set of holes may be proximal to the valve.

[0019] The device may comprise a single lumen.

[0020] The lumen may comprise a first section extending from the proximal end, having a first diameter, and a second section extending from the distal end, having a second diameter different to the first diameter, wherein the first diameter is greater than the second diameter.

[0021] Leaflets of the valve may be thinner than 15 % of a diameter of the base of the valve.

[0022] An effective height of the valve may be 30 to 60 % of the base of the valve.

[0023] The valve may taper towards the distal end.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Non-limiting examples of the present disclosure will be described in the following, with reference to the appended drawings, in which:

[0026] Figure 1 shows a device for removing a clot from a vessel;

[0027] Figure 2 shows a cross section of a part of a distal region of the device of Figure 1 ;

[0028] Figures 3A and 3B show pressure distributions along engagement zones of devices having cylindrical and frustoconical sets of holes, respectively;

[0029] Figures 4A and 4B show a valve of the device;

[0030] Figure 5 shows a flowchart of a method of using a device for removing a clot from a vessel; and

[0031] Figure 6A shows a coaxial thrombectomy system inserted in a vascular system, and Figures 6B and 6C show a device for removing a clot from a vessel in use in the vascular system.

[0032] DETAILED DESCRIPTION OF EXAMPLES

[0033] Figure 1 shows a device 100, which in some examples may be termed a retrieval device, for removing a (blood) clot or thrombus or other occlusion from a vessel. The device comprises a catheter body 110, a set of holes 120 and a lumen 130. The catheter body 110 is for insertion into the vessel (e.g., artery or vein). The catheter body 110 may be a flexible tube. A proximal end 111 of the catheter body 110 is attachable to an aspirator, such as a pump or a syringe, via a connection hub 200. Attaching the proximal end 111 of the catheter body 110 to an aspirator enables, for instance, a negative pressure to be applied at the set of holes 120. In this way, the device 100 may be used to retrieve a clot by engaging the clot by suction. In other words, the clot adheres to the device 100. Advantageously, this technique typically causes less trauma to the vessel from which the clot is removed compared with removing a clot using a stent. Further advantageously, this technique typically reduces the likelihood of fragmentation of the clot during its removal compared with removing a clot using a stent or compared with removing a clot using a conventional aspiration device in which the clot is ingested.

[0034] The catheter body 110 comprises an interior surface and an exterior surface. In one example, the catheter body 110 comprises a plurality of layers. The catheter body 110 may comprise a reinforcing layer. The reinforcing layer may comprise a mesh of wires or braids that, advantageously, reinforce (e.g., strengthen) the catheter body 110. The catheter body 110 may comprise a hydrophilic coating that, advantageously, facilitates insertion of the catheter body 110 into the vessel. For instance, the exterior surface may be coated with a hydrophilic material. The catheter body may comprise a lubricous liner. For instance, the interior surface may be at least partially covered with a lubricous liner. Advantageously, the lubricous liner facilitates movement of a guidewire within the lumen.

[0035] As shown in Figure 1, the set of holes 120 is located towards a distal end 112 in a distal region of the catheter body 110. The distal region may extend between 5 and 30 mm, preferably between 5 and 25 mm, more preferably between 10 and 15 mm, from the distal end 112 towards the proximal end 111. As discussed, the set of holes 120 is configured to engage (e.g., retain) the clot by suction such that the clot adheres to the catheter body 110.

[0036] The set of holes 120 is arranged circumferentially on the catheter body 110. Being arranged circumferentially means that the set of holes 120 is arranged around the perimeter of the catheter body 110. In other words, the arrangement of the set of holes 120 is non-linear. This arrangement is in contrast to the arrangement of holes conventionally seen in catheter bodies, which is usually linear. In one example, the lumen 130 of the catheter body 110 is circular, and the set of the holes 120 is staggered along the circumference of the catheter body 110. For instance, holes of the set of holes 120 may be distributed radially with respect to a longitudinal axis of the lumen, and an angular spacing between adjacent holes 120 may be 180 degrees or less. Advantageously, it has been found that this circumferential arrangement of the holes 120 facilitates adhesion of the clot to the catheter body 110 and enables longitudinal control of the clot. More specifically, irrespective of the orientation of the device 100, because the set of holes 120 is distributed circumferentially, a clot may be retrieved from the vessel. Further advantageously, the set of holes 120 being on a lateral surface of the catheter body 100 creates a greater surface area for engagement. Resultingly, a smaller device 100 (e.g., a catheter body 110 having a smaller diameter) may be used without comprising performance, thereby enabling the 100 device described herein to be used in smaller vessels than conventional aspiration devices.

[0037] The holes 120 may be uniform. In other words, each of the holes 120 may have the same geometry (e.g., dimensions). The set of holes 120 may be arranged to form a helicoidal pattern, a double-helicoidal pattern or diamond-shaped pattern. Advantageously, these patterns may facilitate greater structural integrity of the catheter body 110 by avoiding passing through wires or braids of the reinforcing layer, which are typically arranged to form a grid.

[0038] The part of the catheter body 110 in which the set of holes 120 is arranged may be termed an engagement zone 113. The engagement zone 113 may correspond to a length of 2 to 10 mm of the catheter body 110. The set of holes 120 may have a spatial distribution of 4 to 16 holes per mm of length of the engagement zone 113. Advantageously, this length of the engagement zone 113 and this spatial distribution have been found, in some cases, to enable sufficient pressure to be applied to clots to retrieve them. In other words, a lower spatial distribution of the set of holes 120 may result in application of insufficient pressure for removal of typical clots. On the other hand, in some cases, a higher spatial distribution of the set of holes 120 may significantly impact the structural integrity of the catheter body 11. This length of the engagement zone 113 and this spatial distribution, in combination with the pattern formed by the set of holes 120, may contribute to increased flexibility and resistance to kink deformation.

[0039] Figure 2 shows a cross section of a part of the distal region of the device 100 of Figure 1. As shown in Figure 2, in which the lumen 130 is defined by a wall 131 of the catheter body 110, at least one (e.g., a subset) of the set of holes 120 may be a frustoconical hole. In other words, the term hole is used to mean a duct or passage extending through the wall 131 of the catheter body 110 whose diameter may vary.

[0040] The at least one frustoconical hole may have a greater diameter 121 at the exterior surface of the catheter body 110 compared with a diameter 122 at the interior surface of the catheter body 110. For example, the diameter 122 of the at least one of the set of holes 120 at the interior surface may be 0.05 to 0.26 mm, and the diameter 121 of the at least one of the set of holes 120 at the exterior surface may be 0.12 to 0.51 mm. Advantageously, compared with cylindrical holes, for example, frustoconical holes have been found to achieve better adhesion of the catheter body 110, via the set of holes 120, to a clot due to the Venturi effect. Relatedly, and further advantageously, by using frustoconical holes, due to the Venturi effect, loss of pressure via holes of the set of holes 120 that are not in contact with, for example, the clot or walls or the vessel is reduced.

[0041] The benefit provided by the provision of frustoconical holes compared with cylindrical holes can be understood through Figures 3A and 3B. Figures 3A and 3B show pressure distributions along engagement zones 113 of devices 100 having cylindrical and frustoconical sets of holes 120, respectively. In Figure 3A, the set of holes 120 comprises 24 circumferentially distributed cylindrical holes, each hole having a diameter of 0.254 mm (0.010 inches). In Figure 3B, the set of holes 120 comprises 24 circumferentially distributed frustoconical holes, each hole having a diameter at the interior surface of 0.102 mm (0.004 inches) and a diameter at the exterior surface of 0.254 mm (0.010 inches). A pressure of -80 kPa has been applied in both cases. As can be seen from Figures 3A and 3B, the pressure along the engagement zone shown in Figure 3B is lower that the pressure along the engagement zone 113 shown in Figure 3A. In particular, in contrast to Figure 3A, in Figure 3B a negative pressure is observed along the length of the engagement zone 113.

[0042] The lumen 130, defined by the interior surface, extends between the proximal end 111 and the distal end 112 of the catheter body 110. As alluded to, the lumen 130 is configured to receive a guidewire (the guidewire 300 is shown in Figure 4A and 6B) or any other such device for endovascular treatment. The lumen 130 may be configured to receive a guidewire having a diameter of 0.25 to 0.61 mm. The lumen may be configured to receive a stent- retriever having a diameter up to 4 mm. The lumen 130 may be circular. The diameter of the lumen 130 may be constant or may vary along the length of the catheter body 110.

[0043] The lumen 130 may comprise a first section having a first inner diameter, a first outer diameter and a second section having a second inner diameter and a second outer diameter different to the first diameter. The first section may extend from the proximal end 111, and the second section may extend from the distal end 112, whereby the first section and the second section converge at a convergence section (i.e., a section where the first diameter and the second diameter coincide). Preferably, the convergence section is tapered. The first section may be 70 to 95% of the total length of the device 100. The second section may be 5 to 30% of the total length of the device 100. The first diameter may be greater than the second diameter, thereby, advantageously, facilitating a greater flow rate while maintaining a diameter of the lumen 130 towards the distal end 112 that is suitable for small vessels. In one example, the first section has a length of 155 to 160 cm, a first inner diameter of 0.89 to 1.14 mm (0.035 to 0.045 inches) and a first outer diameter of 1.27 to 1.52 mm (0.050 to 0.060 inches); the convergence section has a length of 5 to 11 cm; and the second section has a length of 4 to 10 cm, a second inner diameter of 0.36 to 0.69 mm (0.014 to 0.027 inches) and a second outer diameter of 0.61 to 1.02 mm (0.024 to 0.040 inches).

[0044] The distal region may comprise a tapered portion. For example, the tip of the catheter body 110 may be tapered. Advantageously, tapering may improve the effectiveness of the device 100. For example, the tapering portion, on contacting a clot in a vessel, may interact with the clot without causing it to fragment and / or without pushing the clot further along the vessel. By crossing the clot, necessary pressure may be applied to the clot, facilitating its removal. By avoiding fragmenting the clot, which is more likely to occur for a blunt or flat distal region, repeat treatments or periprocedural embolic complications may be avoided.

[0045] The distal region (e.g., the tapered portion) comprises a valve region 114. The valve region 114 is a part of the distal region that includes a valve 115 (see Figures 4A and 4B). The valve region 114 and the engagement zone 113 may form a working zone, which may correspond to the distal region. The valve region 114 may comprise a distal aperture. The valve 115 may comprise a valve distal aperture opposite a base. The base is a foundational structure or surface where, in the case of the valve 115 comprising leaflets, leaflets may be mounted or connected. The valve 115 is arranged such that the valve distal aperture is closer to the distal aperture than the base is to the distal aperture.

[0046] In one example, the distal aperture is frustoconical. In other words, the width of the distal aperture decreases towards the distal end 112 such that the valve region 114 comprises a tapering passage. Advantageously, as described above in relation to the set of holes 120, this frustoconical geometry may reduce pressure losses via the distal aperture when the distal aperture is open. In other examples, the distal aperture is lobular or toroidal.

[0047] The valve 115 may be configured to close in response to pressure within a predetermined range. Advantageously, pressure losses via the distal aperture may be avoided when the device 100 is being used to retrieve a clot by the valve 115 only opening when subject to a pressure outside the predetermined range. In one example, the valve 115 is configured to close when the pressure within the lumen 130 is below a threshold value. For instance, an initial state of the valve 115 is open (state 0) and on applying a pressure (e.g., -10 to -95 kPa) the valve 115 adopts a closed state (state 1). The guidewire, which passes through the distal aperture, may be used to guide the catheter body 110 to the location of a clot in a vessel. On removal of the guidewire, a vacuum may then be applied to the interior of the catheter body 110 (i.e., the lumen) to cause the valve 115 to close prior to retrieving the clot. The valve 115 having an initial open state means that, advantageously, the lumen 130 may be continuously flushed by saline solution (when not applying negative pressure for suction), thereby avoiding blood entering into the lumen 130.

[0048] The device may comprise a control wire configured to engage with the valve 115 to control opening and / or closing of the valve 115. For example, the control wire may be attached to the valve 115 such that pulling the control wire causes the valve 115 to close. The valve 115 may be biased to return to an open state when a force is not exerted on the valve 115 by the control wire.

[0049] In the case of the valve 115 comprising leaflets, the valve 115 may be defined by various dimensions that are shown in the zoom of the valve 115 in Figure 4A. These dimensions include geometric height 115-1 , effective height 115-2, base diameter 115-3 and coaptation height 115-4. The geometric height 115-1 is an anatomical distance from a lowest leaflet attachment point to a midpoint of a free edge of the leaflet along the surface of the leaflet itself. The effective height 115-2 is a perpendicular (vertical) distance from the base 115-3 to the midpoint of the free edge of a closed leaflet. Coaptation height 115-4 is a vertical distance (or overlap) between leaflets (cusps) of a valve when the leaflets are closed. The coaptation height 115-4 may be less than 50% of the effective height 115-2. A thickness of a single leaflet may vary. For example, leaflets may be thicker at the base and thinner at the edge (leaflet tip / valve cuspid). As illustrated in Figures 4A and 4B, the base may be circular, defining the base diameter 115-3, leaflets extending therefrom to form a lobular shape.

[0050] The effective height 115-2 may be 30 to 60 % of the base diameter 115-3. Advantageously, these proportions minimise stiffness towards the distal end 112 for smooth navigation of delicate vessels. The effective height 115-2 may be from 0.1 to 0.42 mm. In one example, the base diameter 115-3 is 0.43 mm and the effective height 115-2 is 0.26 mm.

[0051] In one example, the valve 115 is orientated such that it tapers towards the distal end 112. In another example, the valve 115 is orientated such that it tapers away from the distal end 112. Advantageously, the valve 115 being orientated such that it tapers away from the distal end 112 promotes automatic closure of the valve 115 upon fluid injection, meaning that the fluid exits through the holes 120, but, in contrast to the example in which the valve 115 is orientated such that it tapers towards the distal end, not via the distal aperture.

[0052] In one example, the valve 115 is a trileaflet valve. An initial state of the trileaflet valve may be open or closed. In the case that the initial state of the trileaflet valve is open and is configured to close in response to pressure within a predetermined range, the diameter of the valve distal aperture may be equal to or less than the diameter of the holes 120 in the engagement zone 113, and leaflets of the trileaflet valve may be thinner than 15 % of the diameter of the base of the valve 115. Advantageously, this thickness maintains the integrity of the valve 115 while not inhibiting flushing of the valve 115 (e.g., with a saline solution) necessary to clear air bubbles before use of the device 100 and maintain patency of the device lumen to prevent complications like blood clotting during the use of the device 100. The base diameter 115-3 may be 0.43mm, the diameter 122 at the interior surface of the catheter body 110 may be 0.1 mm, a thickness of the leaflets may be 10 microns, a diameter of the valve distal aperture may be 25 pm. In the case that the initial state of the trileaflet valve is closed and the guidewire is used to open the valve 115, leaflets of the trileaflet valve may be thinner than 15 % of the diameter of the base. In another example, the valve 115 is a duckbill valve. In the case that the initial state of the duckbill valve is closed and the guidewire is used to open the valve 115, leaflets of the duckbill valve are thinner than 15 % of the diameter of the base. For instance, the diameter of the base may be 0.43 mm, and each leaflet may have a thickness from 10 to 65 pm; the diameter of the base may be 1 mm, and each leaflet may have a thickness no more than 150 pm. Advantageously, this thickness maintains the integrity of the valve 115 while not inhibiting flushing of the valve 115 (e.g., with a saline solution) necessary to clear air bubbles before use of the device 100 and maintain patency of the device lumen to prevent complications like blood clotting during the use of the device 100.

[0053] The trileaflet valve and the duckbill valve may comprise a material of a low durometer scale (shore O or shore A scale). For example, the trileaflet valve and the duckbill aperture may comprise polyurethane, polyurethane with additives or gel-based polymers.

[0054] Figures 4A and 4B show the valve 115 in situ in more detail. The valve 115 shown in Figure 4A tapers towards the distal end 112. The upper part of Figure 4A shows the valve 115 in an open state and also shows the guidewire 300. The lower part of Figure 4B shows the valve 300 in a closed state, the guidewire 300 having been removed. Figure 4B shows various examples of the valve 115 as a trileaflet valve. In Figure 4B(i), the valve distal aperture is 0.01 mm, and the thickness of the leaflets is 0.01 mm. In Figure 4B(ii), the valve distal aperture is 0.025 mm, and the thickness of the leaflets is 0.01 mm. In Figure 4B(iii), the valve distal aperture is 0.05 mm, and the thickness of the leaflets is 0.01 mm. In Figure 4B(iv), the valve distal aperture is 0.1 mm, and a thickness of the leaflets is 0.01 mm.

[0055] The distal region (e.g., the tapered portion) may comprise a collapse-prone region. The collapse-prone region may form part of the valve region 114 and / or valve 115. For example, advantageously, the collapse-prone region may facilitate closing of the valve 115 by collapsing in response to pressure changes (e.g., pressure decreases) in the lumen. The collapse-prone region may comprise one or more of polytetrafluoroethylene, polyethylene or polypropylene. The thickness of the wall 131 of the catheter body 110 in the collapse-prone region may be less than a thickness of the wall 131 of the catheter body 110 in the rest of the device 100. For example, the thickness of the wall 131 of the catheter body 110 in the collapse-prone region 116 may be less than or equal to 200 pm (e.g., from 150 to 200 pm or as thin as 100 pm).

[0056] The distal region may comprise an antithrombic material and / or an antithrombic additive. Advantageously, the inclusion of an antithrombic material and / or an antithrombic additive in the distal region may reduce or prevent clotting around the valve 115.

[0057] The device 100 may comprise a single lumen 130. Existing aspiration devices often comprise more than one lumen. For example, some existing devices have a first lumen that is involved in aspiration of clots and a second lumen that is for receiving the guidewire. The reason for having two lumen is because there is a permanent opening at the distal end 112 through which the guidewire passes, through which pressure may be lost, for example. However, having more than more lumen negatively impacts performance. Having more than one lumen increases the volume and rigidity of the catheter body. Consequently, devices that comprise a catheter body that has more than one lumen are typically too large and inflexible to reach small vessels that may be occluded by a clot.

[0058] The device 100 may comprise a radiopaque element. For instance, the exterior surface may comprise a radiopaque material. Advantageously, use of one or more radiopaque elements may allow visualization of all or part of the device 100 during use (i.e., under fluoroscopy).

[0059] Figure 5 shows a flowchart of a method of using a device, such as the device 100 of Figure 1. The method shown in Figure 5 is best understood when considered in conjunction with Figures 6A, 6B and 6C.

[0060] The method comprises inserting S1 the guidewire (the guidewire 300 is shown in Figure 6B) and the catheter body 110 into a vascular system (e.g., a cerebral artery). As mentioned, the guidewire 300 passes through the catheter body 110 to aid guiding of the catheter body 110 to the location of the clot or thrombus.

[0061] Figure 6A shows a coaxial thrombectomy system 400 inserted in a vascular system 1000 in which a clot 1001 is located. The coaxial thrombectomy system 400 is unable to reach the clot 100 due to, for instance, the narrowing of the vessels at the location of the clot. The process of inserting S1 the catheter body 110 into the vascular system 1000 in which a clot 1001 is located is shown in Figure 6B. The method comprises advancing S2 the guidewire 300 and the catheter body 110 towards the site of the clot. In the case that the valve 115 is initially closed, the method may comprise pushing the valve 115 open using the guidewire 300.

[0062] As shown in Figure 6B, the method comprises engaging S3 (e.g., contacting) the clot 1001 with the distal region of the catheter body 110. For example, engaging S3 the clot 1001 with the distal region of the catheter body 110 may comprise crossing the site of the clot 1001 with the tapered portion of the catheter body 110. Advantageously, because the set of holes 120 is distributed circumferentially, contacting the clot 1001 with the distal region of the catheter body 110 does not require rotation of the catheter body 110.

[0063] The method comprises removing S4 the guidewire 300 from the lumen 130 of the catheter body 110. As described above, by removing S4 the guidewire 300 from the catheter body 110, it becomes possible to close the distal aperture at the distal end 112 through which the guidewire 300 passes. Consequently, the magnitude of the (negative) pressure applied by the device 100 through the engagement zone 113 can be maximised.

[0064] The method comprises attaching S5 the proximal end 111 of the catheter body 110 to an aspirator and initiating suction. Initiating aspiration may comprise closing the valve 115 by changing the pressure within the catheter body 110 to be within the predetermined range. As described above, and as illustrated in Figure 6C, closing the valve 115 by changing the pressure within the catheter body 110 may be implemented by a collapse-prone region of the distal region. Relatedly, the method may comprise controlling (i.e., opening and / or closing) the valve 115 using a control wire (see above). The process of initiating suction is shown in Figure 6C according to one example. In Figure 6C, the valve 115 is closed. Curved arrows indicate pressure vectors.

[0065] The method comprises withdrawing S6 the catheter body 110 to retrieve the clot.

[0066] In the case that the device 100 comprises a radiopaque element. The method may comprise aligning the radiopaque element with a proximal face of the clot. The radiopaque element enables optimal positioning of the device 100 relative to the clot. In summary, there is provided a device and a method of using a device that enables retrieval of clots, including from small vessels, with improved performance compared with conventional devices and methods, inter alia, due to the presence of features that maximise the strength of clot retention by the retrieval device.

[0067] For completeness, various aspects of the present disclosure are set out in the following numbered clauses:

[0068] Clause 1 : A device 100 for removing a clot from a vessel, the device 100 comprising: a catheter body 110 for insertion into the vessel, wherein the catheter body 110 is attachable to an aspirator at a proximal end 111 of the catheter body 110, wherein the catheter body 110 comprises an interior surface and an exterior surface, wherein the catheter body 110 comprises a lumen 130 extending between the proximal end 111 and a distal end 112, and wherein the lumen 130 is configured to receive a guidewire 300; and a set of holes 120 towards the distal end 112 of the catheter body 110 in a distal region, wherein the set of holes 120 is configured to engage the clot by suction, and wherein the set of holes 120 is arranged circumferentially on the catheter body 110.

[0069] Clause 2: The device 100 of clause 1 , wherein at least one of the set of holes 120 is a frustoconical hole.

[0070] Clause 3: The device 100 of clause 2, wherein the at least one frustoconical hole has a greater diameter at the exterior surface of the catheter body 110 compared with at the interior surface of the catheter body 110.

[0071] Clause 4: The device 100 of clause 3, wherein the diameter of the at least one of the set of holes 120 at the interior surface is 0.05 to 0.26 mm and at the exterior surface is 0.12 to 0.51 mm.

[0072] Clause 5: The device 100 of any preceding clause, wherein the distal region comprises a tapered portion.

[0073] Clause 6: The device 100 of any preceding clause, wherein the distal region comprises a valve region 114 including a valve 115. Clause 7: The device 100 of any preceding clause, wherein the distal region comprises a collapse-prone region.

[0074] Clause 8: The device 100 of clause 6 or 7, wherein the valve region 114 comprises a distal aperture, and wherein the distal aperture is frustoconical.

[0075] Clause 9: The device 100 of any of clauses 6 to 8, wherein an initial state of the valve 115 is open, and the valve 115 is configured to close in response to pressure within the lumen 130 being within a predetermined range.

[0076] Clause 10: The device 100 of any of clauses 6 to 8, wherein an initial state of the valve 115 is closed, and the valve 115 is configured to open in response to pressure within the lumen 130 being within a predetermined range.

[0077] Clause 11: The device 100 of any preceding clause, wherein the set of holes 120 is distributed radially with respect to a longitudinal axis of the lumen 130, and wherein an angular spacing between adjacent holes is 180 degrees or less.

[0078] Clause 12: The device 100 of any preceding clause, wherein the set of holes 120 is distributed along an engagement zone 113 in the distal region, and wherein the set of holes 120 has a spatial distribution of 4 to 16 holes per mm of length of the engagement zone 113.

[0079] Clause 13: The device 100 of any preceding clause, wherein the set of holes 120 forms a helicoidal pattern, a double-helicoidal pattern or diamond-shaped pattern.

[0080] Clause 14: The device 100 of any of clauses 5 to 13, wherein the set of holes 120 is distributed along the tapered portion.

[0081] Clause 15: The device 100 of any preceding clause, wherein the device 100 comprises a single lumen.

[0082] Clause 16: The device 100 of any preceding clause, wherein the lumen 130 comprises a first section extending from the proximal end 111 , having a first diameter, and a second section extending from the distal end 112, having a second diameter different to the first diameter, wherein the first diameter is greater than the second diameter.

[0083] Clause 17: The device 100 of any of clauses 6 to 16, wherein leaflets of the valve 115 are thinner than 15 % of a diameter of the base of the valve 115.

[0084] Clause 18: The device 100 of any of clauses 6 to 17, wherein an effective height of the valve (115) is 30 to 60 % of the base of the valve 115.

[0085] Clause 19: The device 100 of any of clauses 6 to 18, wherein the valve 115 tapers towards the distal end 112.

[0086] Clause 20: The device 100 of any of clauses 6 to 19, wherein the valve 115 tapers away from the distal end 112.

Claims

CLAIMS1. A device (100) for removing a clot from a vessel, the device (100) comprising: a catheter body (110) for insertion into the vessel, wherein the catheter body (110) is attachable to an aspirator at a proximal end (111) of the catheter body (110), wherein the catheter body (110) comprises an interior surface and an exterior surface, wherein the catheter body (110) comprises a lumen (130) extending between the proximal end (111) and a distal end (112), and wherein the lumen (130) is configured to receive a guidewire (300); and a set of holes (120) towards the distal end (112) of the catheter body (110) in a distal region, wherein the set of holes (120) is configured to engage the clot by suction, and wherein the set of holes (120) is arranged circumferentially on the catheter body (110) wherein the distal region comprises a valve region (114) including a valve (115), wherein in an initial state the valve (115) is open, wherein the valve (115) is configured to close in response to a pressure within the lumen (130) being below a threshold value.

2. The device (100) of claim 1, wherein at least one of the set of holes (120) is a frustoconical hole.

3. The device (100) of claim 2, wherein the at least one frustoconical hole has a greater diameter at the exterior surface of the catheter body (110) compared with at the interior surface of the catheter body (110).

4. The device (100) of claim 3, wherein the diameter of the at least one of the set of holes (120) at the interior surface is 0.05 to 0.26 mm and at the exterior surface is 0.12 to 0.51 mm.

5. The device (100) of any preceding claim, wherein the distal region comprises a tapered portion.

6. The device (100) of any preceding claim, wherein the valve region (114) comprises a distal aperture, and wherein the distal aperture is frustoconical.

7. The device (100) of any preceding claim, wherein the set of holes (120) is distributed radially with respect to a longitudinal axis of the lumen (130), and whereinan angular spacing between adjacent holes is 180 degrees or less.

8. The device (100) of any preceding claim, wherein the set of holes (120) is distributed along an engagement zone (113) in the distal region, and wherein the set of holes (120) has a spatial distribution of 4 to 16 holes per mm of length of the engagement zone (113).

9. The device (100) of any preceding claim, wherein the set of holes (120) forms a helicoidal pattern, a double-helicoidal pattern or diamond-shaped pattern.

10. The device (100) of any of claims 5 to 9, wherein the set of holes (120) is distributed along the tapered portion.

11. The device (100) of any preceding claim, wherein the device (100) comprises a single lumen.

12. The device (100) of any preceding claim, wherein the lumen (130) comprises a first section extending from the proximal end 111 , having a first diameter, and a second section extending from the distal end 112, having a second diameter different to the first diameter, wherein the first diameter is greater than the second diameter.

13. The device (100) of any preceding claim, wherein leaflets of the valve (115) are thinner than 15 % of a diameter of the base of the valve (115).

14. The device (100) of any preceding claim, wherein an effective height of the valve (115) is 30 to 60 % of a diameter of the base of the valve (115).

15. The device (100) of any preceding claim, wherein the valve (115) tapers towards the distal end (112).

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